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vfs: fix vfs_rename_dir for FS_RENAME_DOES_D_MOVE filesystems 

vfs_rename_dir() doesn't properly account for filesystems with
FS_RENAME_DOES_D_MOVE.  If new_dentry has a target inode attached, it
unhashes the new_dentry prior to the rename() iop and rehashes it after,
but doesn't account for the possibility that rename() may have swapped
{old,new}_dentry.  For FS_RENAME_DOES_D_MOVE filesystems, it rehashes
new_dentry (now the old renamed-from name, which d_move() expected to go
away), such that a subsequent lookup will find it.  Currently all
FS_RENAME_DOES_D_MOVE filesystems compensate for this by failing in
d_revalidate.

The bug was introduced by: commit 349457ccf2
"[PATCH] Allow file systems to manually d_move() inside of ->rename()"

Fix by not rehashing the new dentry.  Rehashing used to be needed by
d_move() but isn't anymore.

Reported-by: Sage Weil <sage@newdream.net>
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Miklos Szeredi 2011-05-24 13:06:10 -07:00 committed by Al Viro
parent 5c5d3f3b87
commit b5afd2c406
1 changed files with 0 additions and 2 deletions
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2
fs/namei.c
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@ -2989,8 +2989,6 @@ static int vfs_rename_dir(struct inode *old_dir, struct dentry *old_dentry,
dont_mount(new_dentry); dont_mount(new_dentry);
} }
mutex_unlock(&target->i_mutex); mutex_unlock(&target->i_mutex);
if (d_unhashed(new_dentry))
d_rehash(new_dentry);
} }
if (!error) if (!error)
if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE)) if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE))