linux/fs/btrfs/acl.c
Linus Torvalds 815409a12c overlayfs update for 5.15
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Merge tag 'ovl-update-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs

Pull overlayfs update from Miklos Szeredi:

 - Copy up immutable/append/sync/noatime attributes (Amir Goldstein)

 - Improve performance by enabling RCU lookup.

 - Misc fixes and improvements

The reason this touches so many files is that the ->get_acl() method now
gets a "bool rcu" argument.  The ->get_acl() API was updated based on
comments from Al and Linus:

Link: https://lore.kernel.org/linux-fsdevel/CAJfpeguQxpd6Wgc0Jd3ks77zcsAv_bn0q17L3VNnnmPKu11t8A@mail.gmail.com/

* tag 'ovl-update-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
  ovl: enable RCU'd ->get_acl()
  vfs: add rcu argument to ->get_acl() callback
  ovl: fix BUG_ON() in may_delete() when called from ovl_cleanup()
  ovl: use kvalloc in xattr copy-up
  ovl: update ctime when changing fileattr
  ovl: skip checking lower file's i_writecount on truncate
  ovl: relax lookup error on mismatch origin ftype
  ovl: do not set overlay.opaque for new directories
  ovl: add ovl_allow_offline_changes() helper
  ovl: disable decoding null uuid with redirect_dir
  ovl: consistent behavior for immutable/append-only inodes
  ovl: copy up sync/noatime fileattr flags
  ovl: pass ovl_fs to ovl_check_setxattr()
  fs: add generic helper for filling statx attribute flags
2021-09-02 09:21:27 -07:00

163 lines
3.3 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2007 Red Hat. All rights reserved.
*/
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/xattr.h>
#include <linux/posix_acl_xattr.h>
#include <linux/posix_acl.h>
#include <linux/sched.h>
#include <linux/sched/mm.h>
#include <linux/slab.h>
#include "ctree.h"
#include "btrfs_inode.h"
#include "xattr.h"
struct posix_acl *btrfs_get_acl(struct inode *inode, int type, bool rcu)
{
int size;
const char *name;
char *value = NULL;
struct posix_acl *acl;
if (rcu)
return ERR_PTR(-ECHILD);
switch (type) {
case ACL_TYPE_ACCESS:
name = XATTR_NAME_POSIX_ACL_ACCESS;
break;
case ACL_TYPE_DEFAULT:
name = XATTR_NAME_POSIX_ACL_DEFAULT;
break;
default:
return ERR_PTR(-EINVAL);
}
size = btrfs_getxattr(inode, name, NULL, 0);
if (size > 0) {
value = kzalloc(size, GFP_KERNEL);
if (!value)
return ERR_PTR(-ENOMEM);
size = btrfs_getxattr(inode, name, value, size);
}
if (size > 0)
acl = posix_acl_from_xattr(&init_user_ns, value, size);
else if (size == -ENODATA || size == 0)
acl = NULL;
else
acl = ERR_PTR(size);
kfree(value);
return acl;
}
static int __btrfs_set_acl(struct btrfs_trans_handle *trans,
struct user_namespace *mnt_userns,
struct inode *inode, struct posix_acl *acl, int type)
{
int ret, size = 0;
const char *name;
char *value = NULL;
switch (type) {
case ACL_TYPE_ACCESS:
name = XATTR_NAME_POSIX_ACL_ACCESS;
break;
case ACL_TYPE_DEFAULT:
if (!S_ISDIR(inode->i_mode))
return acl ? -EINVAL : 0;
name = XATTR_NAME_POSIX_ACL_DEFAULT;
break;
default:
return -EINVAL;
}
if (acl) {
unsigned int nofs_flag;
size = posix_acl_xattr_size(acl->a_count);
/*
* We're holding a transaction handle, so use a NOFS memory
* allocation context to avoid deadlock if reclaim happens.
*/
nofs_flag = memalloc_nofs_save();
value = kmalloc(size, GFP_KERNEL);
memalloc_nofs_restore(nofs_flag);
if (!value) {
ret = -ENOMEM;
goto out;
}
ret = posix_acl_to_xattr(&init_user_ns, acl, value, size);
if (ret < 0)
goto out;
}
if (trans)
ret = btrfs_setxattr(trans, inode, name, value, size, 0);
else
ret = btrfs_setxattr_trans(inode, name, value, size, 0);
out:
kfree(value);
if (!ret)
set_cached_acl(inode, type, acl);
return ret;
}
int btrfs_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
struct posix_acl *acl, int type)
{
int ret;
umode_t old_mode = inode->i_mode;
if (type == ACL_TYPE_ACCESS && acl) {
ret = posix_acl_update_mode(mnt_userns, inode,
&inode->i_mode, &acl);
if (ret)
return ret;
}
ret = __btrfs_set_acl(NULL, mnt_userns, inode, acl, type);
if (ret)
inode->i_mode = old_mode;
return ret;
}
int btrfs_init_acl(struct btrfs_trans_handle *trans,
struct inode *inode, struct inode *dir)
{
struct posix_acl *default_acl, *acl;
int ret = 0;
/* this happens with subvols */
if (!dir)
return 0;
ret = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
if (ret)
return ret;
if (default_acl) {
ret = __btrfs_set_acl(trans, &init_user_ns, inode, default_acl,
ACL_TYPE_DEFAULT);
posix_acl_release(default_acl);
}
if (acl) {
if (!ret)
ret = __btrfs_set_acl(trans, &init_user_ns, inode, acl,
ACL_TYPE_ACCESS);
posix_acl_release(acl);
}
if (!default_acl && !acl)
cache_no_acl(inode);
return ret;
}