From: Dave Chinner <dchinner@xxxxxxxxxx>
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@xxxxxxxxxx>
---
fs/xfs/xfs_trans_ail.c | 43 +++++++++++++++++++++++++++++++-----------
1 file changed, 32 insertions(+), 11 deletions(-)
diff --git a/fs/xfs/xfs_trans_ail.c b/fs/xfs/xfs_trans_ail.c
index 50611d2bcbc2..41e280ef1483 100644
--- a/fs/xfs/xfs_trans_ail.c
+++ b/fs/xfs/xfs_trans_ail.c
@@ -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)
--
2.17.0
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