Commit 65cd913e authored by Amir Goldstein's avatar Amir Goldstein Committed by Miklos Szeredi
Browse files

ovl: invalidate readdir cache on changes to dir with origin 

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: b79e05aa ("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: default avatarAmir Goldstein <amir73il@gmail.com>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
parent 708fa015

fs/overlayfs/overlayfs.h

+27 −3
Original line number Diff line number Diff line
@@ -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);

fs/overlayfs/readdir.c

+0 −12
Original line number Diff line number Diff line
@@ -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;

fs/overlayfs/util.c

+9 −22
Original line number Diff line number Diff line
@@ -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.