1 files changed, 337 insertions, 0 deletions
diff --git a/fs/xfs/scrub/health.c b/fs/xfs/scrub/health.c
new file mode 100644
index 000000000000..3c0f25098b69
--- /dev/null
+++ b/fs/xfs/scrub/health.c
@@ -0,0 +1,337 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2019-2023 Oracle.  All Rights Reserved.
+ * Author: Darrick J. Wong <djwong@kernel.org>
+ */
+#include "xfs.h"
+#include "xfs_fs.h"
+#include "xfs_shared.h"
+#include "xfs_format.h"
+#include "xfs_trans_resv.h"
+#include "xfs_mount.h"
+#include "xfs_btree.h"
+#include "xfs_ag.h"
+#include "xfs_health.h"
+#include "xfs_rtgroup.h"
+#include "scrub/scrub.h"
+#include "scrub/health.h"
+#include "scrub/common.h"
+
+/*
+ * Scrub and In-Core Filesystem Health Assessments
+ * ===============================================
+ *
+ * Online scrub and repair have the time and the ability to perform stronger
+ * checks than we can do from the metadata verifiers, because they can
+ * cross-reference records between data structures.  Therefore, scrub is in a
+ * good position to update the online filesystem health assessments to reflect
+ * the good/bad state of the data structure.
+ *
+ * We therefore extend scrub in the following ways to achieve this:
+ *
+ * 1. Create a "sick_mask" field in the scrub context.  When we're setting up a
+ * scrub call, set this to the default XFS_SICK_* flag(s) for the selected
+ * scrub type (call it A).  Scrub and repair functions can override the default
+ * sick_mask value if they choose.
+ *
+ * 2. If the scrubber returns a runtime error code, we exit making no changes
+ * to the incore sick state.
+ *
+ * 3. If the scrubber finds that A is clean, use sick_mask to clear the incore
+ * sick flags before exiting.
+ *
+ * 4. If the scrubber finds that A is corrupt, use sick_mask to set the incore
+ * sick flags.  If the user didn't want to repair then we exit, leaving the
+ * metadata structure unfixed and the sick flag set.
+ *
+ * 5. Now we know that A is corrupt and the user wants to repair, so run the
+ * repairer.  If the repairer returns an error code, we exit with that error
+ * code, having made no further changes to the incore sick state.
+ *
+ * 6. If repair rebuilds A correctly and the subsequent re-scrub of A is clean,
+ * use sick_mask to clear the incore sick flags.  This should have the effect
+ * that A is no longer marked sick.
+ *
+ * 7. If repair rebuilds A incorrectly, the re-scrub will find it corrupt and
+ * use sick_mask to set the incore sick flags.  This should have no externally
+ * visible effect since we already set them in step (4).
+ *
+ * There are some complications to this story, however.  For certain types of
+ * complementary metadata indices (e.g. inobt/finobt), it is easier to rebuild
+ * both structures at the same time.  The following principles apply to this
+ * type of repair strategy:
+ *
+ * 8. Any repair function that rebuilds multiple structures should update
+ * sick_mask_visible to reflect whatever other structures are rebuilt, and
+ * verify that all the rebuilt structures can pass a scrub check.  The outcomes
+ * of 5-7 still apply, but with a sick_mask that covers everything being
+ * rebuilt.
+ */
+
+/* Map our scrub type to a sick mask and a set of health update functions. */
+
+enum xchk_health_group {
+	XHG_NONE = 1,
+	XHG_FS,
+	XHG_AG,
+	XHG_INO,
+	XHG_RTGROUP,
+};
+
+struct xchk_health_map {
+	enum xchk_health_group	group;
+	unsigned int		sick_mask;
+};
+
+static const struct xchk_health_map type_to_health_flag[XFS_SCRUB_TYPE_NR] = {
+	[XFS_SCRUB_TYPE_PROBE]		= { XHG_NONE,  0 },
+	[XFS_SCRUB_TYPE_SB]		= { XHG_AG,  XFS_SICK_AG_SB },
+	[XFS_SCRUB_TYPE_AGF]		= { XHG_AG,  XFS_SICK_AG_AGF },
+	[XFS_SCRUB_TYPE_AGFL]		= { XHG_AG,  XFS_SICK_AG_AGFL },
+	[XFS_SCRUB_TYPE_AGI]		= { XHG_AG,  XFS_SICK_AG_AGI },
+	[XFS_SCRUB_TYPE_BNOBT]		= { XHG_AG,  XFS_SICK_AG_BNOBT },
+	[XFS_SCRUB_TYPE_CNTBT]		= { XHG_AG,  XFS_SICK_AG_CNTBT },
+	[XFS_SCRUB_TYPE_INOBT]		= { XHG_AG,  XFS_SICK_AG_INOBT },
+	[XFS_SCRUB_TYPE_FINOBT]		= { XHG_AG,  XFS_SICK_AG_FINOBT },
+	[XFS_SCRUB_TYPE_RMAPBT]		= { XHG_AG,  XFS_SICK_AG_RMAPBT },
+	[XFS_SCRUB_TYPE_REFCNTBT]	= { XHG_AG,  XFS_SICK_AG_REFCNTBT },
+	[XFS_SCRUB_TYPE_INODE]		= { XHG_INO, XFS_SICK_INO_CORE },
+	[XFS_SCRUB_TYPE_BMBTD]		= { XHG_INO, XFS_SICK_INO_BMBTD },
+	[XFS_SCRUB_TYPE_BMBTA]		= { XHG_INO, XFS_SICK_INO_BMBTA },
+	[XFS_SCRUB_TYPE_BMBTC]		= { XHG_INO, XFS_SICK_INO_BMBTC },
+	[XFS_SCRUB_TYPE_DIR]		= { XHG_INO, XFS_SICK_INO_DIR },
+	[XFS_SCRUB_TYPE_XATTR]		= { XHG_INO, XFS_SICK_INO_XATTR },
+	[XFS_SCRUB_TYPE_SYMLINK]	= { XHG_INO, XFS_SICK_INO_SYMLINK },
+	[XFS_SCRUB_TYPE_PARENT]		= { XHG_INO, XFS_SICK_INO_PARENT },
+	[XFS_SCRUB_TYPE_RTBITMAP]	= { XHG_RTGROUP, XFS_SICK_RG_BITMAP },
+	[XFS_SCRUB_TYPE_RTSUM]		= { XHG_RTGROUP, XFS_SICK_RG_SUMMARY },
+	[XFS_SCRUB_TYPE_UQUOTA]		= { XHG_FS,  XFS_SICK_FS_UQUOTA },
+	[XFS_SCRUB_TYPE_GQUOTA]		= { XHG_FS,  XFS_SICK_FS_GQUOTA },
+	[XFS_SCRUB_TYPE_PQUOTA]		= { XHG_FS,  XFS_SICK_FS_PQUOTA },
+	[XFS_SCRUB_TYPE_FSCOUNTERS]	= { XHG_FS,  XFS_SICK_FS_COUNTERS },
+	[XFS_SCRUB_TYPE_QUOTACHECK]	= { XHG_FS,  XFS_SICK_FS_QUOTACHECK },
+	[XFS_SCRUB_TYPE_NLINKS]		= { XHG_FS,  XFS_SICK_FS_NLINKS },
+	[XFS_SCRUB_TYPE_DIRTREE]	= { XHG_INO, XFS_SICK_INO_DIRTREE },
+	[XFS_SCRUB_TYPE_METAPATH]	= { XHG_FS,  XFS_SICK_FS_METAPATH },
+	[XFS_SCRUB_TYPE_RGSUPER]	= { XHG_RTGROUP, XFS_SICK_RG_SUPER },
+	[XFS_SCRUB_TYPE_RTRMAPBT]	= { XHG_RTGROUP, XFS_SICK_RG_RMAPBT },
+	[XFS_SCRUB_TYPE_RTREFCBT]	= { XHG_RTGROUP, XFS_SICK_RG_REFCNTBT },
+};
+
+/* Return the health status mask for this scrub type. */
+unsigned int
+xchk_health_mask_for_scrub_type(
+	__u32			scrub_type)
+{
+	return type_to_health_flag[scrub_type].sick_mask;
+}
+
+/*
+ * If the scrub state is clean, add @mask to the scrub sick mask to clear
+ * additional sick flags from the metadata object's sick state.
+ */
+void
+xchk_mark_healthy_if_clean(
+	struct xfs_scrub	*sc,
+	unsigned int		mask)
+{
+	if (!(sc->sm->sm_flags & (XFS_SCRUB_OFLAG_CORRUPT |
+				  XFS_SCRUB_OFLAG_XCORRUPT)))
+		sc->healthy_mask |= mask;
+}
+
+/*
+ * If we're scrubbing a piece of file metadata for the first time, does it look
+ * like it has been zapped?  Skip the check if we just repaired the metadata
+ * and are revalidating it.
+ */
+bool
+xchk_file_looks_zapped(
+	struct xfs_scrub	*sc,
+	unsigned int		mask)
+{
+	ASSERT((mask & ~XFS_SICK_INO_ZAPPED) == 0);
+
+	if (sc->flags & XREP_ALREADY_FIXED)
+		return false;
+
+	return xfs_inode_has_sickness(sc->ip, mask);
+}
+
+/*
+ * Scrub gave the filesystem a clean bill of health, so clear all the indirect
+ * markers of past problems (at least for the fs and ags) so that we can be
+ * healthy again.
+ */
+STATIC void
+xchk_mark_all_healthy(
+	struct xfs_mount	*mp)
+{
+	struct xfs_perag	*pag = NULL;
+	struct xfs_rtgroup	*rtg = NULL;
+
+	xfs_fs_mark_healthy(mp, XFS_SICK_FS_INDIRECT);
+	while ((pag = xfs_perag_next(mp, pag)))
+		xfs_group_mark_healthy(pag_group(pag), XFS_SICK_AG_INDIRECT);
+	while ((rtg = xfs_rtgroup_next(mp, rtg)))
+		xfs_group_mark_healthy(rtg_group(rtg), XFS_SICK_RG_INDIRECT);
+}
+
+/*
+ * Update filesystem health assessments based on what we found and did.
+ *
+ * If the scrubber finds errors, we mark sick whatever's mentioned in
+ * sick_mask, no matter whether this is a first scan or an
+ * evaluation of repair effectiveness.
+ *
+ * Otherwise, no direct corruption was found, so mark whatever's in
+ * sick_mask as healthy.
+ */
+void
+xchk_update_health(
+	struct xfs_scrub	*sc)
+{
+	struct xfs_perag	*pag;
+	struct xfs_rtgroup	*rtg;
+	unsigned int		mask = sc->sick_mask;
+	bool			bad;
+
+	/*
+	 * The HEALTHY scrub type is a request from userspace to clear all the
+	 * indirect flags after a clean scan of the entire filesystem.  As such
+	 * there's no sick flag defined for it, so we branch here ahead of the
+	 * mask check.
+	 */
+	if (sc->sm->sm_type == XFS_SCRUB_TYPE_HEALTHY &&
+	    !(sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)) {
+		xchk_mark_all_healthy(sc->mp);
+		return;
+	}
+
+	bad = (sc->sm->sm_flags & (XFS_SCRUB_OFLAG_CORRUPT |
+				   XFS_SCRUB_OFLAG_XCORRUPT));
+	if (!bad)
+		mask |= sc->healthy_mask;
+	switch (type_to_health_flag[sc->sm->sm_type].group) {
+	case XHG_NONE:
+		break;
+	case XHG_AG:
+		if (!mask)
+			return;
+		pag = xfs_perag_get(sc->mp, sc->sm->sm_agno);
+		if (bad)
+			xfs_group_mark_corrupt(pag_group(pag), mask);
+		else
+			xfs_group_mark_healthy(pag_group(pag), mask);
+		xfs_perag_put(pag);
+		break;
+	case XHG_INO:
+		if (!sc->ip)
+			return;
+		/*
+		 * If we're coming in for repairs then we don't want sickness
+		 * flags to propagate to the incore health status if the inode
+		 * gets inactivated before we can fix it.
+		 */
+		if (sc->sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR)
+			mask |= XFS_SICK_INO_FORGET;
+		if (!mask)
+			return;
+		if (bad)
+			xfs_inode_mark_corrupt(sc->ip, mask);
+		else
+			xfs_inode_mark_healthy(sc->ip, mask);
+		break;
+	case XHG_FS:
+		if (!mask)
+			return;
+		if (bad)
+			xfs_fs_mark_corrupt(sc->mp, mask);
+		else
+			xfs_fs_mark_healthy(sc->mp, mask);
+		break;
+	case XHG_RTGROUP:
+		if (!mask)
+			return;
+		rtg = xfs_rtgroup_get(sc->mp, sc->sm->sm_agno);
+		if (bad)
+			xfs_group_mark_corrupt(rtg_group(rtg), mask);
+		else
+			xfs_group_mark_healthy(rtg_group(rtg), mask);
+		xfs_rtgroup_put(rtg);
+		break;
+	default:
+		ASSERT(0);
+		break;
+	}
+}
+
+/* Is the given per-AG btree healthy enough for scanning? */
+void
+xchk_ag_btree_del_cursor_if_sick(
+	struct xfs_scrub	*sc,
+	struct xfs_btree_cur	**curp,
+	unsigned int		sm_type)
+{
+	unsigned int		mask = (*curp)->bc_ops->sick_mask;
+
+	/*
+	 * We always want the cursor if it's the same type as whatever we're
+	 * scrubbing, even if we already know the structure is corrupt.
+	 *
+	 * Otherwise, we're only interested in the btree for cross-referencing.
+	 * If we know the btree is bad then don't bother, just set XFAIL.
+	 */
+	if (sc->sm->sm_type == sm_type)
+		return;
+
+	/*
+	 * If we just repaired some AG metadata, sc->sick_mask will reflect all
+	 * the per-AG metadata types that were repaired.  Exclude these from
+	 * the filesystem health query because we have not yet updated the
+	 * health status and we want everything to be scanned.
+	 */
+	if ((sc->flags & XREP_ALREADY_FIXED) &&
+	    type_to_health_flag[sc->sm->sm_type].group == XHG_AG)
+		mask &= ~sc->sick_mask;
+
+	if (xfs_group_has_sickness((*curp)->bc_group, mask)) {
+		sc->sm->sm_flags |= XFS_SCRUB_OFLAG_XFAIL;
+		xfs_btree_del_cursor(*curp, XFS_BTREE_NOERROR);
+		*curp = NULL;
+	}
+}
+
+/*
+ * Quick scan to double-check that there isn't any evidence of lingering
+ * primary health problems.  If we're still clear, then the health update will
+ * take care of clearing the indirect evidence.
+ */
+int
+xchk_health_record(
+	struct xfs_scrub	*sc)
+{
+	struct xfs_mount	*mp = sc->mp;
+	struct xfs_perag	*pag = NULL;
+	struct xfs_rtgroup	*rtg = NULL;
+	unsigned int		sick;
+	unsigned int		checked;
+
+	xfs_fs_measure_sickness(mp, &sick, &checked);
+	if (sick & XFS_SICK_FS_PRIMARY)
+		xchk_set_corrupt(sc);
+
+	while ((pag = xfs_perag_next(mp, pag))) {
+		xfs_group_measure_sickness(pag_group(pag), &sick, &checked);
+		if (sick & XFS_SICK_AG_PRIMARY)
+			xchk_set_corrupt(sc);
+	}
+
+	while ((rtg = xfs_rtgroup_next(mp, rtg))) {
+		xfs_group_measure_sickness(rtg_group(rtg), &sick, &checked);
+		if (sick & XFS_SICK_RG_PRIMARY)
+			xchk_set_corrupt(sc);
+	}
+
+	return 0;
+}