xfs: don't leave EFIs on AIL on mount failure

Log recovery occurs in two phases at mount time. In the first phase,
EFIs and EFDs are processed and potentially cancelled out. EFIs without
EFD objects are inserted into the AIL for processing and recovery in the
second phase. xfs_mountfs() runs various other operations between the
phases and is thus subject to failure. If failure occurs after the first
phase but before the second, pending EFIs sit on the AIL, pin it and
cause the mount to hang.

Update the mount sequence to ensure that pending EFIs are cancelled in
the event of failure. Add a recovery cancellation mechanism to iterate
the AIL and cancel all EFI items when requested. Plumb cancellation
support through the log mount finish helper and update xfs_mountfs() to
invoke cancellation in the event of failure after recovery has started.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

1 files changed, 59 insertions, 4 deletions

diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
index 05c0cc83f9a4..fd1ae47de511 100644
--- a/fs/xfs/xfs_log_recover.c
+++ b/fs/xfs/xfs_log_recover.c
@@ -3791,10 +3791,10 @@ abort_error:
  */
 STATIC int
 xlog_recover_process_efis(
-	struct xlog	*log)
+	struct xlog		*log)
 {
-	xfs_log_item_t		*lip;
-	xfs_efi_log_item_t	*efip;
+	struct xfs_log_item	*lip;
+	struct xfs_efi_log_item	*efip;
 	int			error = 0;
 	struct xfs_ail_cursor	cur;
 	struct xfs_ail		*ailp;
@@ -3818,7 +3818,7 @@ xlog_recover_process_efis(
 		/*
 		 * Skip EFIs that we've already processed.
 		 */
-		efip = (xfs_efi_log_item_t *)lip;
+		efip = container_of(lip, struct xfs_efi_log_item, efi_item);
 		if (test_bit(XFS_EFI_RECOVERED, &efip->efi_flags)) {
 			lip = xfs_trans_ail_cursor_next(ailp, &cur);
 			continue;
@@ -3838,6 +3838,50 @@ out:
 }
 
 /*
+ * A cancel occurs when the mount has failed and we're bailing out. Release all
+ * pending EFIs so they don't pin the AIL.
+ */
+STATIC int
+xlog_recover_cancel_efis(
+	struct xlog		*log)
+{
+	struct xfs_log_item	*lip;
+	struct xfs_efi_log_item	*efip;
+	int			error = 0;
+	struct xfs_ail_cursor	cur;
+	struct xfs_ail		*ailp;
+
+	ailp = log->l_ailp;
+	spin_lock(&ailp->xa_lock);
+	lip = xfs_trans_ail_cursor_first(ailp, &cur, 0);
+	while (lip != NULL) {
+		/*
+		 * We're done when we see something other than an EFI.
+		 * There should be no EFIs left in the AIL now.
+		 */
+		if (lip->li_type != XFS_LI_EFI) {
+#ifdef DEBUG
+			for (; lip; lip = xfs_trans_ail_cursor_next(ailp, &cur))
+				ASSERT(lip->li_type != XFS_LI_EFI);
+#endif
+			break;
+		}
+
+		efip = container_of(lip, struct xfs_efi_log_item, efi_item);
+
+		spin_unlock(&ailp->xa_lock);
+		xfs_efi_release(efip);
+		spin_lock(&ailp->xa_lock);
+
+		lip = xfs_trans_ail_cursor_next(ailp, &cur);
+	}
+
+	xfs_trans_ail_cursor_done(&cur);
+	spin_unlock(&ailp->xa_lock);
+	return error;
+}
+
+/*
  * This routine performs a transaction to null out a bad inode pointer
  * in an agi unlinked inode hash bucket.
  */
@@ -4610,6 +4654,17 @@ xlog_recover_finish(
 	return 0;
 }
 
+int
+xlog_recover_cancel(
+	struct xlog	*log)
+{
+	int		error = 0;
+
+	if (log->l_flags & XLOG_RECOVERY_NEEDED)
+		error = xlog_recover_cancel_efis(log);
+
+	return error;
+}
 
 #if defined(DEBUG)
 /*