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linux-next/fs/overlayfs/dir.c

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overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
/*
*
* Copyright (C) 2011 Novell Inc.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published by
* the Free Software Foundation.
*/
#include <linux/fs.h>
#include <linux/namei.h>
#include <linux/xattr.h>
#include <linux/security.h>
#include <linux/cred.h>
#include <linux/posix_acl.h>
#include <linux/posix_acl_xattr.h>
#include <linux/atomic.h>
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
#include "overlayfs.h"
void ovl_cleanup(struct inode *wdir, struct dentry *wdentry)
{
int err;
dget(wdentry);
VFS: (Scripted) Convert S_ISLNK/DIR/REG(dentry->d_inode) to d_is_*(dentry) Convert the following where appropriate: (1) S_ISLNK(dentry->d_inode) to d_is_symlink(dentry). (2) S_ISREG(dentry->d_inode) to d_is_reg(dentry). (3) S_ISDIR(dentry->d_inode) to d_is_dir(dentry). This is actually more complicated than it appears as some calls should be converted to d_can_lookup() instead. The difference is whether the directory in question is a real dir with a ->lookup op or whether it's a fake dir with a ->d_automount op. In some circumstances, we can subsume checks for dentry->d_inode not being NULL into this, provided we the code isn't in a filesystem that expects d_inode to be NULL if the dirent really *is* negative (ie. if we're going to use d_inode() rather than d_backing_inode() to get the inode pointer). Note that the dentry type field may be set to something other than DCACHE_MISS_TYPE when d_inode is NULL in the case of unionmount, where the VFS manages the fall-through from a negative dentry to a lower layer. In such a case, the dentry type of the negative union dentry is set to the same as the type of the lower dentry. However, if you know d_inode is not NULL at the call site, then you can use the d_is_xxx() functions even in a filesystem. There is one further complication: a 0,0 chardev dentry may be labelled DCACHE_WHITEOUT_TYPE rather than DCACHE_SPECIAL_TYPE. Strictly, this was intended for special directory entry types that don't have attached inodes. The following perl+coccinelle script was used: use strict; my @callers; open($fd, 'git grep -l \'S_IS[A-Z].*->d_inode\' |') || die "Can't grep for S_ISDIR and co. callers"; @callers = <$fd>; close($fd); unless (@callers) { print "No matches\n"; exit(0); } my @cocci = ( '@@', 'expression E;', '@@', '', '- S_ISLNK(E->d_inode->i_mode)', '+ d_is_symlink(E)', '', '@@', 'expression E;', '@@', '', '- S_ISDIR(E->d_inode->i_mode)', '+ d_is_dir(E)', '', '@@', 'expression E;', '@@', '', '- S_ISREG(E->d_inode->i_mode)', '+ d_is_reg(E)' ); my $coccifile = "tmp.sp.cocci"; open($fd, ">$coccifile") || die $coccifile; print($fd "$_\n") || die $coccifile foreach (@cocci); close($fd); foreach my $file (@callers) { chomp $file; print "Processing ", $file, "\n"; system("spatch", "--sp-file", $coccifile, $file, "--in-place", "--no-show-diff") == 0 || die "spatch failed"; } [AV: overlayfs parts skipped] Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-01-29 20:02:35 +08:00
if (d_is_dir(wdentry))
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
err = ovl_do_rmdir(wdir, wdentry);
else
err = ovl_do_unlink(wdir, wdentry);
dput(wdentry);
if (err) {
pr_err("overlayfs: cleanup of '%pd2' failed (%i)\n",
wdentry, err);
}
}
struct dentry *ovl_lookup_temp(struct dentry *workdir, struct dentry *dentry)
{
struct dentry *temp;
char name[20];
static atomic_t temp_id = ATOMIC_INIT(0);
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
/* counter is allowed to wrap, since temp dentries are ephemeral */
snprintf(name, sizeof(name), "#%x", atomic_inc_return(&temp_id));
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
temp = lookup_one_len(name, workdir, strlen(name));
if (!IS_ERR(temp) && temp->d_inode) {
pr_err("overlayfs: workdir/%s already exists\n", name);
dput(temp);
temp = ERR_PTR(-EIO);
}
return temp;
}
/* caller holds i_mutex on workdir */
static struct dentry *ovl_whiteout(struct dentry *workdir,
struct dentry *dentry)
{
int err;
struct dentry *whiteout;
struct inode *wdir = workdir->d_inode;
whiteout = ovl_lookup_temp(workdir, dentry);
if (IS_ERR(whiteout))
return whiteout;
err = ovl_do_whiteout(wdir, whiteout);
if (err) {
dput(whiteout);
whiteout = ERR_PTR(err);
}
return whiteout;
}
int ovl_create_real(struct inode *dir, struct dentry *newdentry,
struct kstat *stat, const char *link,
struct dentry *hardlink, bool debug)
{
int err;
if (newdentry->d_inode)
return -ESTALE;
if (hardlink) {
err = ovl_do_link(hardlink, dir, newdentry, debug);
} else {
switch (stat->mode & S_IFMT) {
case S_IFREG:
err = ovl_do_create(dir, newdentry, stat->mode, debug);
break;
case S_IFDIR:
err = ovl_do_mkdir(dir, newdentry, stat->mode, debug);
break;
case S_IFCHR:
case S_IFBLK:
case S_IFIFO:
case S_IFSOCK:
err = ovl_do_mknod(dir, newdentry,
stat->mode, stat->rdev, debug);
break;
case S_IFLNK:
err = ovl_do_symlink(dir, newdentry, link, debug);
break;
default:
err = -EPERM;
}
}
if (!err && WARN_ON(!newdentry->d_inode)) {
/*
* Not quite sure if non-instantiated dentry is legal or not.
* VFS doesn't seem to care so check and warn here.
*/
err = -ENOENT;
}
return err;
}
static int ovl_set_opaque(struct dentry *upperdentry)
{
return ovl_do_setxattr(upperdentry, OVL_XATTR_OPAQUE, "y", 1, 0);
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
}
static void ovl_remove_opaque(struct dentry *upperdentry)
{
int err;
err = ovl_do_removexattr(upperdentry, OVL_XATTR_OPAQUE);
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
if (err) {
pr_warn("overlayfs: failed to remove opaque from '%s' (%i)\n",
upperdentry->d_name.name, err);
}
}
static int ovl_dir_getattr(struct vfsmount *mnt, struct dentry *dentry,
struct kstat *stat)
{
int err;
enum ovl_path_type type;
struct path realpath;
const struct cred *old_cred;
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
type = ovl_path_real(dentry, &realpath);
old_cred = ovl_override_creds(dentry->d_sb);
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
err = vfs_getattr(&realpath, stat);
revert_creds(old_cred);
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
if (err)
return err;
stat->dev = dentry->d_sb->s_dev;
stat->ino = dentry->d_inode->i_ino;
/*
* It's probably not worth it to count subdirs to get the
* correct link count. nlink=1 seems to pacify 'find' and
* other utilities.
*/
if (OVL_TYPE_MERGE(type))
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
stat->nlink = 1;
return 0;
}
/* Common operations required to be done after creation of file on upper */
static void ovl_instantiate(struct dentry *dentry, struct inode *inode,
struct dentry *newdentry, bool hardlink)
{
ovl_dentry_version_inc(dentry->d_parent);
ovl_dentry_update(dentry, newdentry);
if (!hardlink) {
ovl_inode_update(inode, d_inode(newdentry));
ovl_copyattr(newdentry->d_inode, inode);
} else {
WARN_ON(ovl_inode_real(inode, NULL) != d_inode(newdentry));
inc_nlink(inode);
}
d_instantiate(dentry, inode);
}
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
static int ovl_create_upper(struct dentry *dentry, struct inode *inode,
struct kstat *stat, const char *link,
struct dentry *hardlink)
{
struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
struct inode *udir = upperdir->d_inode;
struct dentry *newdentry;
int err;
if (!hardlink && !IS_POSIXACL(udir))
stat->mode &= ~current_umask();
inode_lock_nested(udir, I_MUTEX_PARENT);
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
newdentry = lookup_one_len(dentry->d_name.name, upperdir,
dentry->d_name.len);
err = PTR_ERR(newdentry);
if (IS_ERR(newdentry))
goto out_unlock;
err = ovl_create_real(udir, newdentry, stat, link, hardlink, false);
if (err)
goto out_dput;
ovl_instantiate(dentry, inode, newdentry, !!hardlink);
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
newdentry = NULL;
out_dput:
dput(newdentry);
out_unlock:
inode_unlock(udir);
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
return err;
}
static int ovl_lock_rename_workdir(struct dentry *workdir,
struct dentry *upperdir)
{
/* Workdir should not be the same as upperdir */
if (workdir == upperdir)
goto err;
/* Workdir should not be subdir of upperdir and vice versa */
if (lock_rename(workdir, upperdir) != NULL)
goto err_unlock;
return 0;
err_unlock:
unlock_rename(workdir, upperdir);
err:
pr_err("overlayfs: failed to lock workdir+upperdir\n");
return -EIO;
}
static struct dentry *ovl_clear_empty(struct dentry *dentry,
struct list_head *list)
{
struct dentry *workdir = ovl_workdir(dentry);
struct inode *wdir = workdir->d_inode;
struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
struct inode *udir = upperdir->d_inode;
struct path upperpath;
struct dentry *upper;
struct dentry *opaquedir;
struct kstat stat;
int err;
if (WARN_ON(!workdir))
return ERR_PTR(-EROFS);
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
err = ovl_lock_rename_workdir(workdir, upperdir);
if (err)
goto out;
ovl_path_upper(dentry, &upperpath);
err = vfs_getattr(&upperpath, &stat);
if (err)
goto out_unlock;
err = -ESTALE;
if (!S_ISDIR(stat.mode))
goto out_unlock;
upper = upperpath.dentry;
if (upper->d_parent->d_inode != udir)
goto out_unlock;
opaquedir = ovl_lookup_temp(workdir, dentry);
err = PTR_ERR(opaquedir);
if (IS_ERR(opaquedir))
goto out_unlock;
err = ovl_create_real(wdir, opaquedir, &stat, NULL, NULL, true);
if (err)
goto out_dput;
err = ovl_copy_xattr(upper, opaquedir);
if (err)
goto out_cleanup;
err = ovl_set_opaque(opaquedir);
if (err)
goto out_cleanup;
inode_lock(opaquedir->d_inode);
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
err = ovl_set_attr(opaquedir, &stat);
inode_unlock(opaquedir->d_inode);
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
if (err)
goto out_cleanup;
err = ovl_do_rename(wdir, opaquedir, udir, upper, RENAME_EXCHANGE);
if (err)
goto out_cleanup;
ovl_cleanup_whiteouts(upper, list);
ovl_cleanup(wdir, upper);
unlock_rename(workdir, upperdir);
/* dentry's upper doesn't match now, get rid of it */
d_drop(dentry);
return opaquedir;
out_cleanup:
ovl_cleanup(wdir, opaquedir);
out_dput:
dput(opaquedir);
out_unlock:
unlock_rename(workdir, upperdir);
out:
return ERR_PTR(err);
}
static struct dentry *ovl_check_empty_and_clear(struct dentry *dentry)
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
{
int err;
struct dentry *ret = NULL;
enum ovl_path_type type = ovl_path_type(dentry);
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
LIST_HEAD(list);
err = ovl_check_empty_dir(dentry, &list);
if (err) {
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
ret = ERR_PTR(err);
goto out_free;
}
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
/*
* When removing an empty opaque directory, then it makes no sense to
* replace it with an exact replica of itself.
*
* If no upperdentry then skip clearing whiteouts.
*
* Can race with copy-up, since we don't hold the upperdir mutex.
* Doesn't matter, since copy-up can't create a non-empty directory
* from an empty one.
*/
if (OVL_TYPE_UPPER(type) && OVL_TYPE_MERGE(type))
ret = ovl_clear_empty(dentry, &list);
out_free:
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
ovl_cache_free(&list);
return ret;
}
static int ovl_set_upper_acl(struct dentry *upperdentry, const char *name,
const struct posix_acl *acl)
{
void *buffer;
size_t size;
int err;
if (!IS_ENABLED(CONFIG_FS_POSIX_ACL) || !acl)
return 0;
size = posix_acl_to_xattr(NULL, acl, NULL, 0);
buffer = kmalloc(size, GFP_KERNEL);
if (!buffer)
return -ENOMEM;
size = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
err = size;
if (err < 0)
goto out_free;
err = vfs_setxattr(upperdentry, name, buffer, size, XATTR_CREATE);
out_free:
kfree(buffer);
return err;
}
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
struct kstat *stat, const char *link,
struct dentry *hardlink)
{
struct dentry *workdir = ovl_workdir(dentry);
struct inode *wdir = workdir->d_inode;
struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
struct inode *udir = upperdir->d_inode;
struct dentry *upper;
struct dentry *newdentry;
int err;
struct posix_acl *acl, *default_acl;
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
if (WARN_ON(!workdir))
return -EROFS;
if (!hardlink) {
err = posix_acl_create(dentry->d_parent->d_inode,
&stat->mode, &default_acl, &acl);
if (err)
return err;
}
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
err = ovl_lock_rename_workdir(workdir, upperdir);
if (err)
goto out;
newdentry = ovl_lookup_temp(workdir, dentry);
err = PTR_ERR(newdentry);
if (IS_ERR(newdentry))
goto out_unlock;
upper = lookup_one_len(dentry->d_name.name, upperdir,
dentry->d_name.len);
err = PTR_ERR(upper);
if (IS_ERR(upper))
goto out_dput;
err = ovl_create_real(wdir, newdentry, stat, link, hardlink, true);
if (err)
goto out_dput2;
/*
* mode could have been mutilated due to umask (e.g. sgid directory)
*/
if (!hardlink &&
!S_ISLNK(stat->mode) && newdentry->d_inode->i_mode != stat->mode) {
struct iattr attr = {
.ia_valid = ATTR_MODE,
.ia_mode = stat->mode,
};
inode_lock(newdentry->d_inode);
err = notify_change(newdentry, &attr, NULL);
inode_unlock(newdentry->d_inode);
if (err)
goto out_cleanup;
}
if (!hardlink) {
err = ovl_set_upper_acl(newdentry, XATTR_NAME_POSIX_ACL_ACCESS,
acl);
if (err)
goto out_cleanup;
err = ovl_set_upper_acl(newdentry, XATTR_NAME_POSIX_ACL_DEFAULT,
default_acl);
if (err)
goto out_cleanup;
}
if (!hardlink && S_ISDIR(stat->mode)) {
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
err = ovl_set_opaque(newdentry);
if (err)
goto out_cleanup;
err = ovl_do_rename(wdir, newdentry, udir, upper,
RENAME_EXCHANGE);
if (err)
goto out_cleanup;
ovl_cleanup(wdir, upper);
} else {
err = ovl_do_rename(wdir, newdentry, udir, upper, 0);
if (err)
goto out_cleanup;
}
ovl_instantiate(dentry, inode, newdentry, !!hardlink);
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
newdentry = NULL;
out_dput2:
dput(upper);
out_dput:
dput(newdentry);
out_unlock:
unlock_rename(workdir, upperdir);
out:
if (!hardlink) {
posix_acl_release(acl);
posix_acl_release(default_acl);
}
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
return err;
out_cleanup:
ovl_cleanup(wdir, newdentry);
goto out_dput2;
}
static int ovl_create_or_link(struct dentry *dentry, struct inode *inode,
struct kstat *stat, const char *link,
struct dentry *hardlink)
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
{
int err;
const struct cred *old_cred;
struct cred *override_cred;
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
err = ovl_copy_up(dentry->d_parent);
if (err)
return err;
old_cred = ovl_override_creds(dentry->d_sb);
err = -ENOMEM;
override_cred = prepare_creds();
if (override_cred) {
override_cred->fsuid = inode->i_uid;
override_cred->fsgid = inode->i_gid;
if (!hardlink) {
err = security_dentry_create_files_as(dentry,
stat->mode, &dentry->d_name, old_cred,
override_cred);
if (err) {
put_cred(override_cred);
goto out_revert_creds;
}
}
put_cred(override_creds(override_cred));
put_cred(override_cred);
if (!ovl_dentry_is_whiteout(dentry))
err = ovl_create_upper(dentry, inode, stat, link,
hardlink);
else
err = ovl_create_over_whiteout(dentry, inode, stat,
link, hardlink);
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
}
out_revert_creds:
revert_creds(old_cred);
if (!err) {
struct inode *realinode = d_inode(ovl_dentry_upper(dentry));
WARN_ON(inode->i_mode != realinode->i_mode);
WARN_ON(!uid_eq(inode->i_uid, realinode->i_uid));
WARN_ON(!gid_eq(inode->i_gid, realinode->i_gid));
}
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
return err;
}
static int ovl_create_object(struct dentry *dentry, int mode, dev_t rdev,
const char *link)
{
int err;
struct inode *inode;
struct kstat stat = {
.rdev = rdev,
};
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
err = ovl_want_write(dentry);
if (err)
goto out;
err = -ENOMEM;
inode = ovl_new_inode(dentry->d_sb, mode, rdev);
if (!inode)
goto out_drop_write;
inode_init_owner(inode, dentry->d_parent->d_inode, mode);
stat.mode = inode->i_mode;
err = ovl_create_or_link(dentry, inode, &stat, link, NULL);
if (err)
iput(inode);
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
out_drop_write:
ovl_drop_write(dentry);
out:
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
return err;
}
static int ovl_create(struct inode *dir, struct dentry *dentry, umode_t mode,
bool excl)
{
return ovl_create_object(dentry, (mode & 07777) | S_IFREG, 0, NULL);
}
static int ovl_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
{
return ovl_create_object(dentry, (mode & 07777) | S_IFDIR, 0, NULL);
}
static int ovl_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
dev_t rdev)
{
/* Don't allow creation of "whiteout" on overlay */
if (S_ISCHR(mode) && rdev == WHITEOUT_DEV)
return -EPERM;
return ovl_create_object(dentry, mode, rdev, NULL);
}
static int ovl_symlink(struct inode *dir, struct dentry *dentry,
const char *link)
{
return ovl_create_object(dentry, S_IFLNK, 0, link);
}
static int ovl_link(struct dentry *old, struct inode *newdir,
struct dentry *new)
{
int err;
struct inode *inode;
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
err = ovl_want_write(old);
if (err)
goto out;
err = ovl_copy_up(old);
if (err)
goto out_drop_write;
inode = d_inode(old);
ihold(inode);
err = ovl_create_or_link(new, inode, NULL, NULL, ovl_dentry_upper(old));
if (err)
iput(inode);
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
out_drop_write:
ovl_drop_write(old);
out:
return err;
}
static int ovl_remove_and_whiteout(struct dentry *dentry, bool is_dir)
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
{
struct dentry *workdir = ovl_workdir(dentry);
struct inode *wdir = workdir->d_inode;
struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
struct inode *udir = upperdir->d_inode;
struct dentry *whiteout;
struct dentry *upper;
struct dentry *opaquedir = NULL;
int err;
int flags = 0;
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
if (WARN_ON(!workdir))
return -EROFS;
if (is_dir) {
opaquedir = ovl_check_empty_and_clear(dentry);
err = PTR_ERR(opaquedir);
if (IS_ERR(opaquedir))
goto out;
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
}
err = ovl_lock_rename_workdir(workdir, upperdir);
if (err)
goto out_dput;
upper = lookup_one_len(dentry->d_name.name, upperdir,
dentry->d_name.len);
err = PTR_ERR(upper);
if (IS_ERR(upper))
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
goto out_unlock;
err = -ESTALE;
if ((opaquedir && upper != opaquedir) ||
(!opaquedir && ovl_dentry_upper(dentry) &&
upper != ovl_dentry_upper(dentry))) {
goto out_dput_upper;
}
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
whiteout = ovl_whiteout(workdir, dentry);
err = PTR_ERR(whiteout);
if (IS_ERR(whiteout))
goto out_dput_upper;
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
if (d_is_dir(upper))
flags = RENAME_EXCHANGE;
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
err = ovl_do_rename(wdir, whiteout, udir, upper, flags);
if (err)
goto kill_whiteout;
if (flags)
ovl_cleanup(wdir, upper);
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
ovl_dentry_version_inc(dentry->d_parent);
out_d_drop:
d_drop(dentry);
dput(whiteout);
out_dput_upper:
dput(upper);
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
out_unlock:
unlock_rename(workdir, upperdir);
out_dput:
dput(opaquedir);
out:
return err;
kill_whiteout:
ovl_cleanup(wdir, whiteout);
goto out_d_drop;
}
static int ovl_remove_upper(struct dentry *dentry, bool is_dir)
{
struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
struct inode *dir = upperdir->d_inode;
struct dentry *upper;
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
int err;
inode_lock_nested(dir, I_MUTEX_PARENT);
upper = lookup_one_len(dentry->d_name.name, upperdir,
dentry->d_name.len);
err = PTR_ERR(upper);
if (IS_ERR(upper))
goto out_unlock;
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
err = -ESTALE;
if (upper == ovl_dentry_upper(dentry)) {
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
if (is_dir)
err = vfs_rmdir(dir, upper);
else
err = vfs_unlink(dir, upper, NULL);
ovl_dentry_version_inc(dentry->d_parent);
}
dput(upper);
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
/*
* Keeping this dentry hashed would mean having to release
* upperpath/lowerpath, which could only be done if we are the
* sole user of this dentry. Too tricky... Just unhash for
* now.
*/
if (!err)
d_drop(dentry);
out_unlock:
inode_unlock(dir);
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
return err;
}
static int ovl_do_remove(struct dentry *dentry, bool is_dir)
{
enum ovl_path_type type;
int err;
const struct cred *old_cred;
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
err = ovl_want_write(dentry);
if (err)
goto out;
err = ovl_copy_up(dentry->d_parent);
if (err)
goto out_drop_write;
type = ovl_path_type(dentry);
old_cred = ovl_override_creds(dentry->d_sb);
if (OVL_TYPE_PURE_UPPER(type))
err = ovl_remove_upper(dentry, is_dir);
else
err = ovl_remove_and_whiteout(dentry, is_dir);
revert_creds(old_cred);
if (!err) {
if (is_dir)
clear_nlink(dentry->d_inode);
else
drop_nlink(dentry->d_inode);
}
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
out_drop_write:
ovl_drop_write(dentry);
out:
return err;
}
static int ovl_unlink(struct inode *dir, struct dentry *dentry)
{
return ovl_do_remove(dentry, false);
}
static int ovl_rmdir(struct inode *dir, struct dentry *dentry)
{
return ovl_do_remove(dentry, true);
}
static int ovl_rename(struct inode *olddir, struct dentry *old,
struct inode *newdir, struct dentry *new,
unsigned int flags)
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
{
int err;
enum ovl_path_type old_type;
enum ovl_path_type new_type;
struct dentry *old_upperdir;
struct dentry *new_upperdir;
struct dentry *olddentry;
struct dentry *newdentry;
struct dentry *trap;
bool old_opaque;
bool new_opaque;
bool cleanup_whiteout = false;
bool overwrite = !(flags & RENAME_EXCHANGE);
VFS: (Scripted) Convert S_ISLNK/DIR/REG(dentry->d_inode) to d_is_*(dentry) Convert the following where appropriate: (1) S_ISLNK(dentry->d_inode) to d_is_symlink(dentry). (2) S_ISREG(dentry->d_inode) to d_is_reg(dentry). (3) S_ISDIR(dentry->d_inode) to d_is_dir(dentry). This is actually more complicated than it appears as some calls should be converted to d_can_lookup() instead. The difference is whether the directory in question is a real dir with a ->lookup op or whether it's a fake dir with a ->d_automount op. In some circumstances, we can subsume checks for dentry->d_inode not being NULL into this, provided we the code isn't in a filesystem that expects d_inode to be NULL if the dirent really *is* negative (ie. if we're going to use d_inode() rather than d_backing_inode() to get the inode pointer). Note that the dentry type field may be set to something other than DCACHE_MISS_TYPE when d_inode is NULL in the case of unionmount, where the VFS manages the fall-through from a negative dentry to a lower layer. In such a case, the dentry type of the negative union dentry is set to the same as the type of the lower dentry. However, if you know d_inode is not NULL at the call site, then you can use the d_is_xxx() functions even in a filesystem. There is one further complication: a 0,0 chardev dentry may be labelled DCACHE_WHITEOUT_TYPE rather than DCACHE_SPECIAL_TYPE. Strictly, this was intended for special directory entry types that don't have attached inodes. The following perl+coccinelle script was used: use strict; my @callers; open($fd, 'git grep -l \'S_IS[A-Z].*->d_inode\' |') || die "Can't grep for S_ISDIR and co. callers"; @callers = <$fd>; close($fd); unless (@callers) { print "No matches\n"; exit(0); } my @cocci = ( '@@', 'expression E;', '@@', '', '- S_ISLNK(E->d_inode->i_mode)', '+ d_is_symlink(E)', '', '@@', 'expression E;', '@@', '', '- S_ISDIR(E->d_inode->i_mode)', '+ d_is_dir(E)', '', '@@', 'expression E;', '@@', '', '- S_ISREG(E->d_inode->i_mode)', '+ d_is_reg(E)' ); my $coccifile = "tmp.sp.cocci"; open($fd, ">$coccifile") || die $coccifile; print($fd "$_\n") || die $coccifile foreach (@cocci); close($fd); foreach my $file (@callers) { chomp $file; print "Processing ", $file, "\n"; system("spatch", "--sp-file", $coccifile, $file, "--in-place", "--no-show-diff") == 0 || die "spatch failed"; } [AV: overlayfs parts skipped] Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-01-29 20:02:35 +08:00
bool is_dir = d_is_dir(old);
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
bool new_is_dir = false;
struct dentry *opaquedir = NULL;
const struct cred *old_cred = NULL;
err = -EINVAL;
if (flags & ~(RENAME_EXCHANGE | RENAME_NOREPLACE))
goto out;
flags &= ~RENAME_NOREPLACE;
/* Don't copy up directory trees */
old_type = ovl_path_type(old);
err = -EXDEV;
if (OVL_TYPE_MERGE_OR_LOWER(old_type) && is_dir)
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
goto out;
if (new->d_inode) {
VFS: (Scripted) Convert S_ISLNK/DIR/REG(dentry->d_inode) to d_is_*(dentry) Convert the following where appropriate: (1) S_ISLNK(dentry->d_inode) to d_is_symlink(dentry). (2) S_ISREG(dentry->d_inode) to d_is_reg(dentry). (3) S_ISDIR(dentry->d_inode) to d_is_dir(dentry). This is actually more complicated than it appears as some calls should be converted to d_can_lookup() instead. The difference is whether the directory in question is a real dir with a ->lookup op or whether it's a fake dir with a ->d_automount op. In some circumstances, we can subsume checks for dentry->d_inode not being NULL into this, provided we the code isn't in a filesystem that expects d_inode to be NULL if the dirent really *is* negative (ie. if we're going to use d_inode() rather than d_backing_inode() to get the inode pointer). Note that the dentry type field may be set to something other than DCACHE_MISS_TYPE when d_inode is NULL in the case of unionmount, where the VFS manages the fall-through from a negative dentry to a lower layer. In such a case, the dentry type of the negative union dentry is set to the same as the type of the lower dentry. However, if you know d_inode is not NULL at the call site, then you can use the d_is_xxx() functions even in a filesystem. There is one further complication: a 0,0 chardev dentry may be labelled DCACHE_WHITEOUT_TYPE rather than DCACHE_SPECIAL_TYPE. Strictly, this was intended for special directory entry types that don't have attached inodes. The following perl+coccinelle script was used: use strict; my @callers; open($fd, 'git grep -l \'S_IS[A-Z].*->d_inode\' |') || die "Can't grep for S_ISDIR and co. callers"; @callers = <$fd>; close($fd); unless (@callers) { print "No matches\n"; exit(0); } my @cocci = ( '@@', 'expression E;', '@@', '', '- S_ISLNK(E->d_inode->i_mode)', '+ d_is_symlink(E)', '', '@@', 'expression E;', '@@', '', '- S_ISDIR(E->d_inode->i_mode)', '+ d_is_dir(E)', '', '@@', 'expression E;', '@@', '', '- S_ISREG(E->d_inode->i_mode)', '+ d_is_reg(E)' ); my $coccifile = "tmp.sp.cocci"; open($fd, ">$coccifile") || die $coccifile; print($fd "$_\n") || die $coccifile foreach (@cocci); close($fd); foreach my $file (@callers) { chomp $file; print "Processing ", $file, "\n"; system("spatch", "--sp-file", $coccifile, $file, "--in-place", "--no-show-diff") == 0 || die "spatch failed"; } [AV: overlayfs parts skipped] Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-01-29 20:02:35 +08:00
if (d_is_dir(new))
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
new_is_dir = true;
new_type = ovl_path_type(new);
err = -EXDEV;
if (!overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir)
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
goto out;
} else {
if (ovl_dentry_is_opaque(new))
new_type = __OVL_PATH_UPPER;
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
else
new_type = __OVL_PATH_UPPER | __OVL_PATH_PURE;
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
}
err = ovl_want_write(old);
if (err)
goto out;
err = ovl_copy_up(old);
if (err)
goto out_drop_write;
err = ovl_copy_up(new->d_parent);
if (err)
goto out_drop_write;
if (!overwrite) {
err = ovl_copy_up(new);
if (err)
goto out_drop_write;
}
old_opaque = !OVL_TYPE_PURE_UPPER(old_type);
new_opaque = !OVL_TYPE_PURE_UPPER(new_type);
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
old_cred = ovl_override_creds(old->d_sb);
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
if (overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir) {
opaquedir = ovl_check_empty_and_clear(new);
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
err = PTR_ERR(opaquedir);
if (IS_ERR(opaquedir)) {
opaquedir = NULL;
goto out_revert_creds;
}
}
if (overwrite) {
if (old_opaque) {
if (!ovl_dentry_is_whiteout(new)) {
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
/* Whiteout source */
flags |= RENAME_WHITEOUT;
} else {
/* Switch whiteouts */
flags |= RENAME_EXCHANGE;
}
} else if (is_dir && ovl_dentry_is_whiteout(new)) {
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
flags |= RENAME_EXCHANGE;
cleanup_whiteout = true;
}
}
old_upperdir = ovl_dentry_upper(old->d_parent);
new_upperdir = ovl_dentry_upper(new->d_parent);
trap = lock_rename(new_upperdir, old_upperdir);
olddentry = lookup_one_len(old->d_name.name, old_upperdir,
old->d_name.len);
err = PTR_ERR(olddentry);
if (IS_ERR(olddentry))
goto out_unlock;
err = -ESTALE;
if (olddentry != ovl_dentry_upper(old))
goto out_dput_old;
newdentry = lookup_one_len(new->d_name.name, new_upperdir,
new->d_name.len);
err = PTR_ERR(newdentry);
if (IS_ERR(newdentry))
goto out_dput_old;
err = -ESTALE;
if (ovl_dentry_upper(new)) {
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
if (opaquedir) {
if (newdentry != opaquedir)
goto out_dput;
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
} else {
if (newdentry != ovl_dentry_upper(new))
goto out_dput;
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
}
} else {
if (!d_is_negative(newdentry) &&
(!new_opaque || !ovl_is_whiteout(newdentry)))
goto out_dput;
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
}
if (olddentry == trap)
goto out_dput;
if (newdentry == trap)
goto out_dput;
if (WARN_ON(olddentry->d_inode == newdentry->d_inode))
goto out_dput;
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
if (is_dir && !old_opaque && new_opaque) {
err = ovl_set_opaque(olddentry);
if (err)
goto out_dput;
}
if (!overwrite && new_is_dir && old_opaque && !new_opaque) {
err = ovl_set_opaque(newdentry);
if (err)
goto out_dput;
}
if (old_opaque || new_opaque) {
err = ovl_do_rename(old_upperdir->d_inode, olddentry,
new_upperdir->d_inode, newdentry,
flags);
} else {
/* No debug for the plain case */
BUG_ON(flags & ~RENAME_EXCHANGE);
err = vfs_rename(old_upperdir->d_inode, olddentry,
new_upperdir->d_inode, newdentry,
NULL, flags);
}
if (err) {
if (is_dir && !old_opaque && new_opaque)
ovl_remove_opaque(olddentry);
if (!overwrite && new_is_dir && old_opaque && !new_opaque)
ovl_remove_opaque(newdentry);
goto out_dput;
}
if (is_dir && old_opaque && !new_opaque)
ovl_remove_opaque(olddentry);
if (!overwrite && new_is_dir && !old_opaque && new_opaque)
ovl_remove_opaque(newdentry);
ovl: ignore lower entries when checking purity of non-directory entries After rename file dentry still holds reference to lower dentry from previous location. This doesn't matter for data access because data comes from upper dentry. But this stale lower dentry taints dentry at new location and turns it into non-pure upper. Such file leaves visible whiteout entry after remove in directory which shouldn't have whiteouts at all. Overlayfs already tracks pureness of file location in oe->opaque. This patch just uses that for detecting actual path type. Comment from Vivek Goyal's patch: Here are the details of the problem. Do following. $ mkdir upper lower work merged upper/dir/ $ touch lower/test $ sudo mount -t overlay overlay -olowerdir=lower,upperdir=upper,workdir= work merged $ mv merged/test merged/dir/ $ rm merged/dir/test $ ls -l merged/dir/ /usr/bin/ls: cannot access merged/dir/test: No such file or directory total 0 c????????? ? ? ? ? ? test Basic problem seems to be that once a file has been unlinked, a whiteout has been left behind which was not needed and hence it becomes visible. Whiteout is visible because parent dir is of not type MERGE, hence od->is_real is set during ovl_dir_open(). And that means ovl_iterate() passes on iterate handling directly to underlying fs. Underlying fs does not know/filter whiteouts so it becomes visible to user. Why did we leave a whiteout to begin with when we should not have. ovl_do_remove() checks for OVL_TYPE_PURE_UPPER() and does not leave whiteout if file is pure upper. In this case file is not found to be pure upper hence whiteout is left. So why file was not PURE_UPPER in this case? I think because dentry is still carrying some leftover state which was valid before rename. For example, od->numlower was set to 1 as it was a lower file. After rename, this state is not valid anymore as there is no such file in lower. Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Reported-by: Viktor Stanchev <me@viktorstanchev.com> Suggested-by: Vivek Goyal <vgoyal@redhat.com> Link: https://bugzilla.kernel.org/show_bug.cgi?id=109611 Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Cc: <stable@vger.kernel.org>
2016-01-31 21:17:53 +08:00
/*
* Old dentry now lives in different location. Dentries in
* lowerstack are stale. We cannot drop them here because
* access to them is lockless. This could be only pure upper
* or opaque directory - numlower is zero. Or upper non-dir
* entry - its pureness is tracked by flag opaque.
*/
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
if (old_opaque != new_opaque) {
ovl_dentry_set_opaque(old, new_opaque);
if (!overwrite)
ovl_dentry_set_opaque(new, old_opaque);
}
if (cleanup_whiteout)
ovl_cleanup(old_upperdir->d_inode, newdentry);
ovl_dentry_version_inc(old->d_parent);
ovl_dentry_version_inc(new->d_parent);
out_dput:
dput(newdentry);
out_dput_old:
dput(olddentry);
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
out_unlock:
unlock_rename(new_upperdir, old_upperdir);
out_revert_creds:
revert_creds(old_cred);
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
out_drop_write:
ovl_drop_write(old);
out:
dput(opaquedir);
return err;
}
const struct inode_operations ovl_dir_inode_operations = {
.lookup = ovl_lookup,
.mkdir = ovl_mkdir,
.symlink = ovl_symlink,
.unlink = ovl_unlink,
.rmdir = ovl_rmdir,
.rename = ovl_rename,
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
.link = ovl_link,
.setattr = ovl_setattr,
.create = ovl_create,
.mknod = ovl_mknod,
.permission = ovl_permission,
.getattr = ovl_dir_getattr,
.listxattr = ovl_listxattr,
.get_acl = ovl_get_acl,
.update_time = ovl_update_time,
overlay filesystem Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24 06:14:38 +08:00
};