xfs: convert log tail checking to a warning

[deliverable/linux.git] / fs / xfs / xfs_log.c

diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index 24643169e63203347b450ffaff60e52279d4462e..b612ce4520aebef7cbc38a066b48133d37f2636d 100644 (file)
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -3407,6 +3407,17 @@ xlog_verify_dest_ptr(
                xfs_emerg(log->l_mp, "%s: invalid ptr", __func__);
 }
 
+/*
+ * Check to make sure the grant write head didn't just over lap the tail.  If
+ * the cycles are the same, we can't be overlapping.  Otherwise, make sure that
+ * the cycles differ by exactly one and check the byte count.
+ *
+ * This check is run unlocked, so can give false positives. Rather than assert
+ * on failures, use a warn-once flag and a panic tag to allow the admin to
+ * determine if they want to panic the machine when such an error occurs. For
+ * debug kernels this will have the same effect as using an assert but, unlinke
+ * an assert, it can be turned off at runtime.
+ */
 STATIC void
 xlog_verify_grant_tail(
        struct log      *log)
@@ -3414,17 +3425,22 @@ xlog_verify_grant_tail(
        int             tail_cycle, tail_blocks;
        int             cycle, space;
 
-       /*
-        * Check to make sure the grant write head didn't just over lap the
-        * tail.  If the cycles are the same, we can't be overlapping.
-        * Otherwise, make sure that the cycles differ by exactly one and
-        * check the byte count.
-        */
        xlog_crack_grant_head(&log->l_grant_write_head, &cycle, &space);
        xlog_crack_atomic_lsn(&log->l_tail_lsn, &tail_cycle, &tail_blocks);
        if (tail_cycle != cycle) {
-               ASSERT(cycle - 1 == tail_cycle);
-               ASSERT(space <= BBTOB(tail_blocks));
+               if (cycle - 1 != tail_cycle &&
+                   !(log->l_flags & XLOG_TAIL_WARN)) {
+                       xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES,
+                               "%s: cycle - 1 != tail_cycle", __func__);
+                       log->l_flags |= XLOG_TAIL_WARN;
+               }
+
+               if (space > BBTOB(tail_blocks) &&
+                   !(log->l_flags & XLOG_TAIL_WARN)) {
+                       xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES,
+                               "%s: space > BBTOB(tail_blocks)", __func__);
+                       log->l_flags |= XLOG_TAIL_WARN;
+               }
        }
 }