tree c15055c81f21b7863318e1e6f8a9620afaeb3327
parent a048d3aff8b828b6c0fa7ddd90a531248ab4e0f9
author Miklos Szeredi <mszeredi@suse.cz> 1215027015 +0200
committer Al Viro <viro@zeniv.linux.org.uk> 1217119985 -0400

[patch] vfs: fix lookup on deleted directory

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>