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ovl: invalidate readdir cache on changes to dir with origin

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The test in ovl_dentry_version_inc() was out-dated and did not include
the case where readdir cache is used on a non-merge dir that has origin
xattr, indicating that it may contain leftover whiteouts.

To make the code more robust, use the same helper ovl_dir_is_real()
to determine if readdir cache should be used and if readdir cache should
be invalidated.

Fixes: b79e05aaa1 ("ovl: no direct iteration for dir with origin xattr")
Link: https://lore.kernel.org/linux-unionfs/CAOQ4uxht70nODhNHNwGFMSqDyOKLXOKrY0H6g849os4BQ7cokA@mail.gmail.com/
Cc: Chris Murphy <lists@colorremedies.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This commit is contained in:
Amir Goldstein 2021-04-11 12:22:23 +03:00 committed by Miklos Szeredi
parent 708fa01597
commit 65cd913ec9
3 changed files with 36 additions and 37 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

30
fs/overlayfs/overlayfs.h
View File

@ -319,9 +319,6 @@ int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
enum ovl_xattr ox, const void *value, size_t size,
int xerr);
int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry);
void ovl_set_flag(unsigned long flag, struct inode *inode);
void ovl_clear_flag(unsigned long flag, struct inode *inode);
bool ovl_test_flag(unsigned long flag, struct inode *inode);
bool ovl_inuse_trylock(struct dentry *dentry);
void ovl_inuse_unlock(struct dentry *dentry);
bool ovl_is_inuse(struct dentry *dentry);
@ -335,6 +332,21 @@ char *ovl_get_redirect_xattr(struct ovl_fs *ofs, struct dentry *dentry,
int padding);
int ovl_sync_status(struct ovl_fs *ofs);
static inline void ovl_set_flag(unsigned long flag, struct inode *inode)
{
set_bit(flag, &OVL_I(inode)->flags);
}
static inline void ovl_clear_flag(unsigned long flag, struct inode *inode)
{
clear_bit(flag, &OVL_I(inode)->flags);
}
static inline bool ovl_test_flag(unsigned long flag, struct inode *inode)
{
return test_bit(flag, &OVL_I(inode)->flags);
}
static inline bool ovl_is_impuredir(struct super_block *sb,
struct dentry *dentry)
{
@ -439,6 +451,18 @@ int ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt,
struct dentry *dentry, int level);
int ovl_indexdir_cleanup(struct ovl_fs *ofs);
/*
* Can we iterate real dir directly?
*
* Non-merge dir may contain whiteouts from a time it was a merge upper, before
* lower dir was removed under it and possibly before it was rotated from upper
* to lower layer.
*/
static inline bool ovl_dir_is_real(struct dentry *dir)
{
return !ovl_test_flag(OVL_WHITEOUTS, d_inode(dir));
}
/* inode.c */
int ovl_set_nlink_upper(struct dentry *dentry);
int ovl_set_nlink_lower(struct dentry *dentry);

12
fs/overlayfs/readdir.c
View File

@ -319,18 +319,6 @@ static inline int ovl_dir_read(struct path *realpath,
return err;
}
/*
* Can we iterate real dir directly?
*
* Non-merge dir may contain whiteouts from a time it was a merge upper, before
* lower dir was removed under it and possibly before it was rotated from upper
* to lower layer.
*/
static bool ovl_dir_is_real(struct dentry *dir)
{
return !ovl_test_flag(OVL_WHITEOUTS, d_inode(dir));
}
static void ovl_dir_reset(struct file *file)
{
struct ovl_dir_file *od = file->private_data;

31
fs/overlayfs/util.c
View File

@ -422,18 +422,20 @@ void ovl_inode_update(struct inode *inode, struct dentry *upperdentry)
}
}
static void ovl_dentry_version_inc(struct dentry *dentry, bool impurity)
static void ovl_dir_version_inc(struct dentry *dentry, bool impurity)
{
struct inode *inode = d_inode(dentry);
WARN_ON(!inode_is_locked(inode));
WARN_ON(!d_is_dir(dentry));
/*
* Version is used by readdir code to keep cache consistent. For merge
* dirs all changes need to be noted. For non-merge dirs, cache only
* contains impure (ones which have been copied up and have origins)
* entries, so only need to note changes to impure entries.
* Version is used by readdir code to keep cache consistent.
* For merge dirs (or dirs with origin) all changes need to be noted.
* For non-merge dirs, cache contains only impure entries (i.e. ones
* which have been copied up and have origins), so only need to note
* changes to impure entries.
*/
if (OVL_TYPE_MERGE(ovl_path_type(dentry)) || impurity)
if (!ovl_dir_is_real(dentry) || impurity)
OVL_I(inode)->version++;
}
@ -442,7 +444,7 @@ void ovl_dir_modified(struct dentry *dentry, bool impurity)
/* Copy mtime/ctime */
ovl_copyattr(d_inode(ovl_dentry_upper(dentry)), d_inode(dentry));
ovl_dentry_version_inc(dentry, impurity);
ovl_dir_version_inc(dentry, impurity);
}
u64 ovl_dentry_version_get(struct dentry *dentry)
@ -638,21 +640,6 @@ int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry)
return err;
}
void ovl_set_flag(unsigned long flag, struct inode *inode)
{
set_bit(flag, &OVL_I(inode)->flags);
}
void ovl_clear_flag(unsigned long flag, struct inode *inode)
{
clear_bit(flag, &OVL_I(inode)->flags);
}
bool ovl_test_flag(unsigned long flag, struct inode *inode)
{
return test_bit(flag, &OVL_I(inode)->flags);
}
/**
* Caller must hold a reference to inode to prevent it from being freed while
* it is marked inuse.