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xfs: don't assert fail with AIL lock held

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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: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
This commit is contained in:
Dave Chinner 2018-05-09 07:49:09 -07:00 committed by Darrick J. Wong
parent e632a5690c
commit d686d12d23
1 changed files with 32 additions and 11 deletions
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43
fs/xfs/xfs_trans_ail.c
View File

@ -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_ail *ailp,
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)