xfs: track metadata health status

Add the necessary in-core metadata fields to keep track of which parts
of the filesystem have been observed and which parts were observed to be
unhealthy, and print a warning at unmount time if we have unfixed
problems.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>

1 files changed, 183 insertions, 0 deletions

diff --git a/fs/xfs/libxfs/xfs_health.h b/fs/xfs/libxfs/xfs_health.h
new file mode 100644
index 000000000000..95053564a0d5
--- /dev/null
+++ b/fs/xfs/libxfs/xfs_health.h
@@ -0,0 +1,183 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2019 Oracle.  All Rights Reserved.
+ * Author: Darrick J. Wong <darrick.wong@oracle.com>
+ */
+#ifndef __XFS_HEALTH_H__
+#define __XFS_HEALTH_H__
+
+/*
+ * In-Core Filesystem Health Assessments
+ * =====================================
+ *
+ * We'd like to be able to summarize the current health status of the
+ * filesystem so that the administrator knows when it's necessary to schedule
+ * some downtime for repairs.  Until then, we would also like to avoid abrupt
+ * shutdowns due to corrupt metadata.
+ *
+ * The online scrub feature evaluates the health of all filesystem metadata.
+ * When scrub detects corruption in a piece of metadata it will set the
+ * corresponding sickness flag, and repair will clear it if successful.  If
+ * problems remain at unmount time, we can also request manual intervention by
+ * logging a notice to run xfs_repair.
+ *
+ * Each health tracking group uses a pair of fields for reporting.  The
+ * "checked" field tell us if a given piece of metadata has ever been examined,
+ * and the "sick" field tells us if that piece was found to need repairs.
+ * Therefore we can conclude that for a given sick flag value:
+ *
+ *  - checked && sick  => metadata needs repair
+ *  - checked && !sick => metadata is ok
+ *  - !checked         => has not been examined since mount
+ */
+
+struct xfs_mount;
+struct xfs_perag;
+struct xfs_inode;
+
+/* Observable health issues for metadata spanning the entire filesystem. */
+#define XFS_SICK_FS_COUNTERS	(1 << 0)  /* summary counters */
+#define XFS_SICK_FS_UQUOTA	(1 << 1)  /* user quota */
+#define XFS_SICK_FS_GQUOTA	(1 << 2)  /* group quota */
+#define XFS_SICK_FS_PQUOTA	(1 << 3)  /* project quota */
+
+/* Observable health issues for realtime volume metadata. */
+#define XFS_SICK_RT_BITMAP	(1 << 0)  /* realtime bitmap */
+#define XFS_SICK_RT_SUMMARY	(1 << 1)  /* realtime summary */
+
+/* Observable health issues for AG metadata. */
+#define XFS_SICK_AG_SB		(1 << 0)  /* superblock */
+#define XFS_SICK_AG_AGF		(1 << 1)  /* AGF header */
+#define XFS_SICK_AG_AGFL	(1 << 2)  /* AGFL header */
+#define XFS_SICK_AG_AGI		(1 << 3)  /* AGI header */
+#define XFS_SICK_AG_BNOBT	(1 << 4)  /* free space by block */
+#define XFS_SICK_AG_CNTBT	(1 << 5)  /* free space by length */
+#define XFS_SICK_AG_INOBT	(1 << 6)  /* inode index */
+#define XFS_SICK_AG_FINOBT	(1 << 7)  /* free inode index */
+#define XFS_SICK_AG_RMAPBT	(1 << 8)  /* reverse mappings */
+#define XFS_SICK_AG_REFCNTBT	(1 << 9)  /* reference counts */
+
+/* Observable health issues for inode metadata. */
+#define XFS_SICK_INO_CORE	(1 << 0)  /* inode core */
+#define XFS_SICK_INO_BMBTD	(1 << 1)  /* data fork */
+#define XFS_SICK_INO_BMBTA	(1 << 2)  /* attr fork */
+#define XFS_SICK_INO_BMBTC	(1 << 3)  /* cow fork */
+#define XFS_SICK_INO_DIR	(1 << 4)  /* directory */
+#define XFS_SICK_INO_XATTR	(1 << 5)  /* extended attributes */
+#define XFS_SICK_INO_SYMLINK	(1 << 6)  /* symbolic link remote target */
+#define XFS_SICK_INO_PARENT	(1 << 7)  /* parent pointers */
+
+/* Primary evidence of health problems in a given group. */
+#define XFS_SICK_FS_PRIMARY	(XFS_SICK_FS_COUNTERS | \
+				 XFS_SICK_FS_UQUOTA | \
+				 XFS_SICK_FS_GQUOTA | \
+				 XFS_SICK_FS_PQUOTA)
+
+#define XFS_SICK_RT_PRIMARY	(XFS_SICK_RT_BITMAP | \
+				 XFS_SICK_RT_SUMMARY)
+
+#define XFS_SICK_AG_PRIMARY	(XFS_SICK_AG_SB | \
+				 XFS_SICK_AG_AGF | \
+				 XFS_SICK_AG_AGFL | \
+				 XFS_SICK_AG_AGI | \
+				 XFS_SICK_AG_BNOBT | \
+				 XFS_SICK_AG_CNTBT | \
+				 XFS_SICK_AG_INOBT | \
+				 XFS_SICK_AG_FINOBT | \
+				 XFS_SICK_AG_RMAPBT | \
+				 XFS_SICK_AG_REFCNTBT)
+
+#define XFS_SICK_INO_PRIMARY	(XFS_SICK_INO_CORE | \
+				 XFS_SICK_INO_BMBTD | \
+				 XFS_SICK_INO_BMBTA | \
+				 XFS_SICK_INO_BMBTC | \
+				 XFS_SICK_INO_DIR | \
+				 XFS_SICK_INO_XATTR | \
+				 XFS_SICK_INO_SYMLINK | \
+				 XFS_SICK_INO_PARENT)
+
+/* These functions must be provided by the xfs implementation. */
+
+void xfs_fs_mark_sick(struct xfs_mount *mp, unsigned int mask);
+void xfs_fs_mark_healthy(struct xfs_mount *mp, unsigned int mask);
+void xfs_fs_measure_sickness(struct xfs_mount *mp, unsigned int *sick,
+		unsigned int *checked);
+
+void xfs_rt_mark_sick(struct xfs_mount *mp, unsigned int mask);
+void xfs_rt_mark_healthy(struct xfs_mount *mp, unsigned int mask);
+void xfs_rt_measure_sickness(struct xfs_mount *mp, unsigned int *sick,
+		unsigned int *checked);
+
+void xfs_ag_mark_sick(struct xfs_perag *pag, unsigned int mask);
+void xfs_ag_mark_healthy(struct xfs_perag *pag, unsigned int mask);
+void xfs_ag_measure_sickness(struct xfs_perag *pag, unsigned int *sick,
+		unsigned int *checked);
+
+void xfs_inode_mark_sick(struct xfs_inode *ip, unsigned int mask);
+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);
+
+/* Now some helpers. */
+
+static inline bool
+xfs_fs_has_sickness(struct xfs_mount *mp, unsigned int mask)
+{
+	unsigned int	sick, checked;
+
+	xfs_fs_measure_sickness(mp, &sick, &checked);
+	return sick & mask;
+}
+
+static inline bool
+xfs_rt_has_sickness(struct xfs_mount *mp, unsigned int mask)
+{
+	unsigned int	sick, checked;
+
+	xfs_rt_measure_sickness(mp, &sick, &checked);
+	return sick & mask;
+}
+
+static inline bool
+xfs_ag_has_sickness(struct xfs_perag *pag, unsigned int mask)
+{
+	unsigned int	sick, checked;
+
+	xfs_ag_measure_sickness(pag, &sick, &checked);
+	return sick & mask;
+}
+
+static inline bool
+xfs_inode_has_sickness(struct xfs_inode *ip, unsigned int mask)
+{
+	unsigned int	sick, checked;
+
+	xfs_inode_measure_sickness(ip, &sick, &checked);
+	return sick & mask;
+}
+
+static inline bool
+xfs_fs_is_healthy(struct xfs_mount *mp)
+{
+	return !xfs_fs_has_sickness(mp, -1U);
+}
+
+static inline bool
+xfs_rt_is_healthy(struct xfs_mount *mp)
+{
+	return !xfs_rt_has_sickness(mp, -1U);
+}
+
+static inline bool
+xfs_ag_is_healthy(struct xfs_perag *pag)
+{
+	return !xfs_ag_has_sickness(pag, -1U);
+}
+
+static inline bool
+xfs_inode_is_healthy(struct xfs_inode *ip)
+{
+	return !xfs_inode_has_sickness(ip, -1U);
+}
+
+#endif	/* __XFS_HEALTH_H__ */