xfs: clear BAD_SUMMARY if unmounting an unhealthy filesystem

If we know the filesystem metadata isn't healthy during unmount, we want
to encourage the administrator to run xfs_repair right away.  We can't
do this if BAD_SUMMARY will cause an unclean log unmount to force
summary recalculation, so turn it off if the fs is bad.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>

fs/xfs/libxfs/xfs_health.h

@@ -118,6 +118,8 @@ void xfs_inode_mark_healthy(struct xfs_inode *ip, unsigned int mask);
 void xfs_inode_measure_sickness(struct xfs_inode *ip, unsigned int *sick,
 		unsigned int *checked);
 
+void xfs_health_unmount(struct xfs_mount *mp);
+
 /* Now some helpers. */
 
 static inline bool

fs/xfs/xfs_health.c

@@ -19,6 +19,80 @@
 #include "xfs_trace.h"
 #include "xfs_health.h"
 
+/*
+ * Warn about metadata corruption that we detected but haven't fixed, and
+ * make sure we're not sitting on anything that would get in the way of
+ * recovery.
+ */
+void
+xfs_health_unmount(
+	struct xfs_mount	*mp)
+{
+	struct xfs_perag	*pag;
+	xfs_agnumber_t		agno;
+	unsigned int		sick = 0;
+	unsigned int		checked = 0;
+	bool			warn = false;
+
+	if (XFS_FORCED_SHUTDOWN(mp))
+		return;
+
+	/* Measure AG corruption levels. */
+	for (agno = 0; agno < mp->m_sb.sb_agcount; agno++) {
+		pag = xfs_perag_get(mp, agno);
+		xfs_ag_measure_sickness(pag, &sick, &checked);
+		if (sick) {
+			trace_xfs_ag_unfixed_corruption(mp, agno, sick);
+			warn = true;
+		}
+		xfs_perag_put(pag);
+	}
+
+	/* Measure realtime volume corruption levels. */
+	xfs_rt_measure_sickness(mp, &sick, &checked);
+	if (sick) {
+		trace_xfs_rt_unfixed_corruption(mp, sick);
+		warn = true;
+	}
+
+	/*
+	 * Measure fs corruption and keep the sample around for the warning.
+	 * See the note below for why we exempt FS_COUNTERS.
+	 */
+	xfs_fs_measure_sickness(mp, &sick, &checked);
+	if (sick & ~XFS_SICK_FS_COUNTERS) {
+		trace_xfs_fs_unfixed_corruption(mp, sick);
+		warn = true;
+	}
+
+	if (warn) {
+		xfs_warn(mp,
+"Uncorrected metadata errors detected; please run xfs_repair.");
+
+		/*
+		 * We discovered uncorrected metadata problems at some point
+		 * during this filesystem mount and have advised the
+		 * administrator to run repair once the unmount completes.
+		 *
+		 * However, we must be careful -- when FSCOUNTERS are flagged
+		 * unhealthy, the unmount procedure omits writing the clean
+		 * unmount record to the log so that the next mount will run
+		 * recovery and recompute the summary counters.  In other
+		 * words, we leave a dirty log to get the counters fixed.
+		 *
+		 * Unfortunately, xfs_repair cannot recover dirty logs, so if
+		 * there were filesystem problems, FSCOUNTERS was flagged, and
+		 * the administrator takes our advice to run xfs_repair,
+		 * they'll have to zap the log before repairing structures.
+		 * We don't really want to encourage this, so we mark the
+		 * FSCOUNTERS healthy so that a subsequent repair run won't see
+		 * a dirty log.
+		 */
+		if (sick & XFS_SICK_FS_COUNTERS)
+			xfs_fs_mark_healthy(mp, XFS_SICK_FS_COUNTERS);
+	}
+}
+
 /* Mark unhealthy per-fs metadata. */
 void
 xfs_fs_mark_sick(

fs/xfs/xfs_mount.c

@@ -1070,6 +1070,7 @@ xfs_mountfs(
 	 */
 	cancel_delayed_work_sync(&mp->m_reclaim_work);
 	xfs_reclaim_inodes(mp, SYNC_WAIT);
+	xfs_health_unmount(mp);
  out_log_dealloc:
 	mp->m_flags |= XFS_MOUNT_UNMOUNTING;
 	xfs_log_mount_cancel(mp);
@@ -1152,6 +1153,7 @@ xfs_unmountfs(
 	 */
 	cancel_delayed_work_sync(&mp->m_reclaim_work);
 	xfs_reclaim_inodes(mp, SYNC_WAIT);
+	xfs_health_unmount(mp);
 
 	xfs_qm_unmount(mp);
 

fs/xfs/xfs_trace.h

@@ -3461,8 +3461,10 @@ DEFINE_EVENT(xfs_fs_corrupt_class, name,	\
 	TP_ARGS(mp, flags))
 DEFINE_FS_CORRUPT_EVENT(xfs_fs_mark_sick);
 DEFINE_FS_CORRUPT_EVENT(xfs_fs_mark_healthy);
+DEFINE_FS_CORRUPT_EVENT(xfs_fs_unfixed_corruption);
 DEFINE_FS_CORRUPT_EVENT(xfs_rt_mark_sick);
 DEFINE_FS_CORRUPT_EVENT(xfs_rt_mark_healthy);
+DEFINE_FS_CORRUPT_EVENT(xfs_rt_unfixed_corruption);
 
 DECLARE_EVENT_CLASS(xfs_ag_corrupt_class,
 	TP_PROTO(struct xfs_mount *mp, xfs_agnumber_t agno, unsigned int flags),
@@ -3488,6 +3490,7 @@ DEFINE_EVENT(xfs_ag_corrupt_class, name,	\
 	TP_ARGS(mp, agno, flags))
 DEFINE_AG_CORRUPT_EVENT(xfs_ag_mark_sick);
 DEFINE_AG_CORRUPT_EVENT(xfs_ag_mark_healthy);
+DEFINE_AG_CORRUPT_EVENT(xfs_ag_unfixed_corruption);
 
 DECLARE_EVENT_CLASS(xfs_inode_corrupt_class,
 	TP_PROTO(struct xfs_inode *ip, unsigned int flags),