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, 24 insertions, 6 deletions

diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index 08d4fe4..7ce278d 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -700,6 +700,7 @@ xfs_log_mount(
 		if (error) {
 			xfs_warn(mp, "log mount/recovery failed: error %d",
 				error);
+			xlog_recover_cancel(mp->m_log);
 			goto out_destroy_ail;
 		}
 	}
@@ -740,18 +741,35 @@ out:
  * it.
  */
 int
-xfs_log_mount_finish(xfs_mount_t *mp)
+xfs_log_mount_finish(
+	struct xfs_mount	*mp)
 {
 	int	error = 0;
 
-	if (!(mp->m_flags & XFS_MOUNT_NORECOVERY)) {
-		error = xlog_recover_finish(mp->m_log);
-		if (!error)
-			xfs_log_work_queue(mp);
-	} else {
+	if (mp->m_flags & XFS_MOUNT_NORECOVERY) {
 		ASSERT(mp->m_flags & XFS_MOUNT_RDONLY);
+		return 0;
 	}
 
+	error = xlog_recover_finish(mp->m_log);
+	if (!error)
+		xfs_log_work_queue(mp);
+
+	return error;
+}
+
+/*
+ * The mount has failed. Cancel the recovery if it hasn't completed and destroy
+ * the log.
+ */
+int
+xfs_log_mount_cancel(
+	struct xfs_mount	*mp)
+{
+	int			error;
+
+	error = xlog_recover_cancel(mp->m_log);
+	xfs_log_unmount(mp);
 
 	return error;
 }