linux/fs/ufs
Arjan van de Ven 5c81a4197d [PATCH] lockdep: annotate the quota code
The quota code plays interesting games with the lock ordering; to quote Jan:

| i_mutex of inode containing quota file is acquired after all other
| quota locks. i_mutex of all other inodes is acquired before quota
| locks. Quota code makes sure (by resetting inode operations and
| setting special flag on inode) that noone tries to enter quota code
| while holding i_mutex on a quota file...

The good news is that all of this special case i_mutex grabbing happens in the
(per filesystem) low level quota write function.  For this special case we
need a new I_MUTEX_* nesting level, since this just entirely outside any of
the regular VFS locking rules for i_mutex.  I trust Jan on his blue eyes that
this is not ever going to deadlock; and based on that the patch below is what
it takes to inform lockdep of these very interesting new locking rules.

The new locking rule for the I_MUTEX_QUOTA nesting level is that this is the
deepest possible level of nesting for i_mutex, and that this only should be
used in quota write (and possibly read) function of filesystems.  This makes
the lock ordering of the I_MUTEX_* levels:

I_MUTEX_PARENT -> I_MUTEX_CHILD -> I_MUTEX_NORMAL -> I_MUTEX_QUOTA

Has no effect on non-lockdep kernels.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Jan Kara <jack@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-03 15:27:08 -07:00
..
balloc.c [PATCH] ufs: truncate should allocate block for last byte 2006-07-01 09:56:03 -07:00
cylinder.c [PATCH] ufs: easy debug 2006-06-25 10:01:03 -07:00
dir.c [PATCH] ufs: little directory lookup optimization 2006-06-25 10:01:03 -07:00
file.c [PATCH] ufs: truncate should allocate block for last byte 2006-07-01 09:56:03 -07:00
ialloc.c [PATCH] ufs: ubh_ll_rw_block cleanup 2006-06-25 10:01:04 -07:00
inode.c [PATCH] ufs: truncate should allocate block for last byte 2006-07-01 09:56:03 -07:00
Makefile Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
namei.c [PATCH] ufs: easy debug 2006-06-25 10:01:03 -07:00
super.c [PATCH] lockdep: annotate the quota code 2006-07-03 15:27:08 -07:00
swab.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
symlink.c [PATCH] Fix up symlink function pointers 2005-08-19 18:08:21 -07:00
truncate.c [PATCH] ufs: truncate should allocate block for last byte 2006-07-01 09:56:03 -07:00
util.c [PATCH] ufs: truncate should allocate block for last byte 2006-07-01 09:56:03 -07:00
util.h [PATCH] ufs: truncate should allocate block for last byte 2006-07-01 09:56:03 -07:00