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-rw-r--r--fs/xfs/xfs_log.c48
1 files changed, 29 insertions, 19 deletions
diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index a2dea108071a..613ed9414e70 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -1000,27 +1000,34 @@ xfs_log_space_wake(
}
/*
- * Determine if we have a transaction that has gone to disk
- * that needs to be covered. To begin the transition to the idle state
- * firstly the log needs to be idle (no AIL and nothing in the iclogs).
- * If we are then in a state where covering is needed, the caller is informed
- * that dummy transactions are required to move the log into the idle state.
+ * Determine if we have a transaction that has gone to disk that needs to be
+ * covered. To begin the transition to the idle state firstly the log needs to
+ * be idle. That means the CIL, the AIL and the iclogs needs to be empty before
+ * we start attempting to cover the log.
*
- * Because this is called as part of the sync process, we should also indicate
- * that dummy transactions should be issued in anything but the covered or
- * idle states. This ensures that the log tail is accurately reflected in
- * the log at the end of the sync, hence if a crash occurrs avoids replay
- * of transactions where the metadata is already on disk.
+ * Only if we are then in a state where covering is needed, the caller is
+ * informed that dummy transactions are required to move the log into the idle
+ * state.
+ *
+ * If there are any items in the AIl or CIL, then we do not want to attempt to
+ * cover the log as we may be in a situation where there isn't log space
+ * available to run a dummy transaction and this can lead to deadlocks when the
+ * tail of the log is pinned by an item that is modified in the CIL. Hence
+ * there's no point in running a dummy transaction at this point because we
+ * can't start trying to idle the log until both the CIL and AIL are empty.
*/
int
xfs_log_need_covered(xfs_mount_t *mp)
{
- int needed = 0;
struct xlog *log = mp->m_log;
+ int needed = 0;
if (!xfs_fs_writable(mp))
return 0;
+ if (!xlog_cil_empty(log))
+ return 0;
+
spin_lock(&log->l_icloglock);
switch (log->l_covered_state) {
case XLOG_STATE_COVER_DONE:
@@ -1029,14 +1036,17 @@ xfs_log_need_covered(xfs_mount_t *mp)
break;
case XLOG_STATE_COVER_NEED:
case XLOG_STATE_COVER_NEED2:
- if (!xfs_ail_min_lsn(log->l_ailp) &&
- xlog_iclogs_empty(log)) {
- if (log->l_covered_state == XLOG_STATE_COVER_NEED)
- log->l_covered_state = XLOG_STATE_COVER_DONE;
- else
- log->l_covered_state = XLOG_STATE_COVER_DONE2;
- }
- /* FALLTHRU */
+ if (xfs_ail_min_lsn(log->l_ailp))
+ break;
+ if (!xlog_iclogs_empty(log))
+ break;
+
+ needed = 1;
+ if (log->l_covered_state == XLOG_STATE_COVER_NEED)
+ log->l_covered_state = XLOG_STATE_COVER_DONE;
+ else
+ log->l_covered_state = XLOG_STATE_COVER_DONE2;
+ break;
default:
needed = 1;
break;
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