Messages in this thread Patch in this message | | | Date | Mon, 4 Aug 2008 13:16:31 -0700 | From | Greg KH <> | Subject | [patch 33/33] vfs: fix lookup on deleted directory |
| |
2.6.25-stable review patch. If anyone has any objections, please let us know.
------------------
From: Miklos Szeredi <mszeredi@suse.cz>
commit d70b67c8bc72ee23b55381bd6a884f4796692f77 upstream
Lookup can install a child dentry for a deleted directory. This keeps the directory dentry alive, and the inode pinned in the cache and on disk, even after all external references have gone away.
This isn't a big problem normally, since memory pressure or umount will clear out the directory dentry and its children, releasing the inode. But for UBIFS this causes problems because its orphan area can overflow.
Fix this by returning ENOENT for all lookups on a S_DEAD directory before creating a child dentry.
Thanks to Zoltan Sogor for noticing this while testing UBIFS, and Artem for the excellent analysis of the problem and testing.
Reported-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Tested-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- fs/namei.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-)
--- a/fs/namei.c +++ b/fs/namei.c @@ -514,7 +514,14 @@ static struct dentry * real_lookup(struc */ result = d_lookup(parent, name); if (!result) { - struct dentry * dentry = d_alloc(parent, name); + struct dentry *dentry; + + /* Don't create child dentry for a dead directory. */ + result = ERR_PTR(-ENOENT); + if (IS_DEADDIR(dir)) + goto out_unlock; + + dentry = d_alloc(parent, name); result = ERR_PTR(-ENOMEM); if (dentry) { result = dir->i_op->lookup(dir, dentry, nd); @@ -523,6 +530,7 @@ static struct dentry * real_lookup(struc else result = dentry; } +out_unlock: mutex_unlock(&dir->i_mutex); return result; } @@ -1313,7 +1321,14 @@ static struct dentry *__lookup_hash(stru dentry = cached_lookup(base, name, nd); if (!dentry) { - struct dentry *new = d_alloc(base, name); + struct dentry *new; + + /* Don't create child dentry for a dead directory. */ + dentry = ERR_PTR(-ENOENT); + if (IS_DEADDIR(inode)) + goto out; + + new = d_alloc(base, name); dentry = ERR_PTR(-ENOMEM); if (!new) goto out; --
| |