Commit d686d12d authored by Dave Chinner's avatar Dave Chinner Committed by Darrick J. Wong
Browse files

xfs: don't assert fail with AIL lock held 



Been hitting AIL ordering assert failures recently, but been unable
to trace them down because the system immediately hangs up onteh
spinlock that was held when this assert fires:

XFS: Assertion failed: XFS_LSN_CMP(prev_lip->li_lsn, lip->li_lsn) <= 0, file: fs/xfs/xfs_trans_ail.c, line: 52

Move the assertions outside of the spinlock so the corpse can
be dissected. Thanks to Brian Foster for supplying a clean
way of doing this.

Signed-Off-By: default avatarDave Chinner <dchinner@redhat.com>
Reviewed-by: default avatarBrian Foster <bfoster@redhat.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
parent e632a569

fs/xfs/xfs_trans_ail.c

+32 −11
Original line number Diff line number Diff line
@@ -32,30 +32,51 @@ 
#ifdef DEBUG

/*

 * Check that the list is sorted as it should be.

 *

 * Called with the ail lock held, but we don't want to assert fail with it

 * held otherwise we'll lock everything up and won't be able to debug the

 * cause. Hence we sample and check the state under the AIL lock and return if

 * everything is fine, otherwise we drop the lock and run the ASSERT checks.

 * Asserts may not be fatal, so pick the lock back up and continue onwards.

 */

STATIC void

xfs_ail_check(

	struct xfs_ail		*ailp,

	xfs_log_item_t	*lip)

	struct xfs_log_item	*lip)

{

	xfs_log_item_t	*prev_lip;

	struct xfs_log_item	*prev_lip;

	struct xfs_log_item	*next_lip;

	xfs_lsn_t		prev_lsn = NULLCOMMITLSN;

	xfs_lsn_t		next_lsn = NULLCOMMITLSN;

	xfs_lsn_t		lsn;

	bool			in_ail;





	if (list_empty(&ailp->ail_head))

		return;



	/*

	 * Check the next and previous entries are valid.

	 * Sample then check the next and previous entries are valid.

	 */

	ASSERT(test_bit(XFS_LI_IN_AIL, &lip->li_flags));

	prev_lip = list_entry(lip->li_ail.prev, xfs_log_item_t, li_ail);

	in_ail = test_bit(XFS_LI_IN_AIL, &lip->li_flags);

	prev_lip = list_entry(lip->li_ail.prev, struct xfs_log_item, li_ail);

	if (&prev_lip->li_ail != &ailp->ail_head)

		ASSERT(XFS_LSN_CMP(prev_lip->li_lsn, lip->li_lsn) <= 0);



	prev_lip = list_entry(lip->li_ail.next, xfs_log_item_t, li_ail);

	if (&prev_lip->li_ail != &ailp->ail_head)

		ASSERT(XFS_LSN_CMP(prev_lip->li_lsn, lip->li_lsn) >= 0);

		prev_lsn = prev_lip->li_lsn;

	next_lip = list_entry(lip->li_ail.next, struct xfs_log_item, li_ail);

	if (&next_lip->li_ail != &ailp->ail_head)

		next_lsn = next_lip->li_lsn;

	lsn = lip->li_lsn;



	if (in_ail &&

	    (prev_lsn == NULLCOMMITLSN || XFS_LSN_CMP(prev_lsn, lsn) <= 0) &&

	    (next_lsn == NULLCOMMITLSN || XFS_LSN_CMP(next_lsn, lsn) >= 0))

		return;



	spin_unlock(&ailp->ail_lock);

	ASSERT(in_ail);

	ASSERT(prev_lsn == NULLCOMMITLSN || XFS_LSN_CMP(prev_lsn, lsn) <= 0);

	ASSERT(next_lsn == NULLCOMMITLSN || XFS_LSN_CMP(next_lsn, lsn) >= 0);

	spin_lock(&ailp->ail_lock);

}

#else /* !DEBUG */

#define	xfs_ail_check(a,l)