From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Plumb in the pieces necessary to make the "scrub" subfunction of
the scrub ioctl actually work. This means that we make the IFLAG_REPAIR
flag to the scrub ioctl actually do something, and we add an errortag
knob so that xfstests can force the kernel to rebuild a metadata
structure even if there's nothing wrong with it.
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
fs/xfs/Kconfig | 18 +++++
fs/xfs/Makefile | 7 ++
fs/xfs/libxfs/xfs_errortag.h | 4 +
fs/xfs/libxfs/xfs_fs.h | 9 ++
fs/xfs/scrub/repair.c | 65 ++++++++++++++++
fs/xfs/scrub/repair.h | 33 ++++++++
fs/xfs/scrub/scrub.c | 168 ++++++++++++++++++++++++++++++++++++++++--
fs/xfs/scrub/scrub.h | 3 +
fs/xfs/xfs_error.c | 3 +
9 files changed, 301 insertions(+), 9 deletions(-)
create mode 100644 fs/xfs/scrub/repair.c
create mode 100644 fs/xfs/scrub/repair.h
diff --git a/fs/xfs/Kconfig b/fs/xfs/Kconfig
index 46bcf0e6..457ac9f 100644
--- a/fs/xfs/Kconfig
+++ b/fs/xfs/Kconfig
@@ -85,6 +85,24 @@ config XFS_ONLINE_SCRUB
If unsure, say N.
+config XFS_ONLINE_REPAIR
+ bool "XFS online metadata repair support"
+ default n
+ depends on XFS_FS && XFS_ONLINE_SCRUB
+ help
+ If you say Y here you will be able to repair metadata on a
+ mounted XFS filesystem. This feature is intended to reduce
+ filesystem downtime by fixing minor problems before they cause the
+ filesystem to go down. However, it requires that the filesystem be
+ formatted with secondary metadata, such as reverse mappings and inode
+ parent pointers.
+
+ This feature is considered EXPERIMENTAL. Use with caution!
+
+ See the xfs_scrub man page in section 8 for additional information.
+
+ If unsure, say N.
+
config XFS_WARN
bool "XFS Verbose Warnings"
depends on XFS_FS && !XFS_DEBUG
diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile
index b03c77e..9175d51 100644
--- a/fs/xfs/Makefile
+++ b/fs/xfs/Makefile
@@ -169,4 +169,11 @@ xfs-y += $(addprefix scrub/, \
xfs-$(CONFIG_XFS_RT) += scrub/rtbitmap.o
xfs-$(CONFIG_XFS_QUOTA) += scrub/quota.o
+
+# online repair
+ifeq ($(CONFIG_XFS_ONLINE_REPAIR),y)
+xfs-y += $(addprefix scrub/, \
+ repair.o \
+ )
+endif
endif
diff --git a/fs/xfs/libxfs/xfs_errortag.h b/fs/xfs/libxfs/xfs_errortag.h
index bc1789d..d47b916 100644
--- a/fs/xfs/libxfs/xfs_errortag.h
+++ b/fs/xfs/libxfs/xfs_errortag.h
@@ -65,7 +65,8 @@
#define XFS_ERRTAG_LOG_BAD_CRC 29
#define XFS_ERRTAG_LOG_ITEM_PIN 30
#define XFS_ERRTAG_BUF_LRU_REF 31
-#define XFS_ERRTAG_MAX 32
+#define XFS_ERRTAG_FORCE_SCRUB_REPAIR 32
+#define XFS_ERRTAG_MAX 33
/*
* Random factors for above tags, 1 means always, 2 means 1/2 time, etc.
@@ -102,5 +103,6 @@
#define XFS_RANDOM_LOG_BAD_CRC 1
#define XFS_RANDOM_LOG_ITEM_PIN 1
#define XFS_RANDOM_BUF_LRU_REF 2
+#define XFS_RANDOM_FORCE_SCRUB_REPAIR 1
#endif /* __XFS_ERRORTAG_H_ */
diff --git a/fs/xfs/libxfs/xfs_fs.h b/fs/xfs/libxfs/xfs_fs.h
index faf1a4e..dddc75e 100644
--- a/fs/xfs/libxfs/xfs_fs.h
+++ b/fs/xfs/libxfs/xfs_fs.h
@@ -542,13 +542,20 @@ struct xfs_scrub_metadata {
/* o: Metadata object looked funny but isn't corrupt. */
#define XFS_SCRUB_OFLAG_WARNING (1 << 6)
+/*
+ * o: IFLAG_REPAIR was set but metadata object did not need fixing or
+ * optimization and has therefore not been altered.
+ */
+#define XFS_SCRUB_OFLAG_NO_REPAIR_NEEDED (1 << 7)
+
#define XFS_SCRUB_FLAGS_IN (XFS_SCRUB_IFLAG_REPAIR)
#define XFS_SCRUB_FLAGS_OUT (XFS_SCRUB_OFLAG_CORRUPT | \
XFS_SCRUB_OFLAG_PREEN | \
XFS_SCRUB_OFLAG_XFAIL | \
XFS_SCRUB_OFLAG_XCORRUPT | \
XFS_SCRUB_OFLAG_INCOMPLETE | \
- XFS_SCRUB_OFLAG_WARNING)
+ XFS_SCRUB_OFLAG_WARNING | \
+ XFS_SCRUB_OFLAG_NO_REPAIR_NEEDED)
#define XFS_SCRUB_FLAGS_ALL (XFS_SCRUB_FLAGS_IN | XFS_SCRUB_FLAGS_OUT)
/*
diff --git a/fs/xfs/scrub/repair.c b/fs/xfs/scrub/repair.c
new file mode 100644
index 0000000..69ffb94
--- /dev/null
+++ b/fs/xfs/scrub/repair.c
@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2018 Oracle. All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+#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_defer.h"
+#include "xfs_btree.h"
+#include "xfs_bit.h"
+#include "xfs_log_format.h"
+#include "xfs_trans.h"
+#include "xfs_sb.h"
+#include "xfs_inode.h"
+#include "xfs_icache.h"
+#include "xfs_alloc.h"
+#include "xfs_alloc_btree.h"
+#include "xfs_ialloc.h"
+#include "xfs_ialloc_btree.h"
+#include "xfs_rmap.h"
+#include "xfs_rmap_btree.h"
+#include "xfs_refcount.h"
+#include "xfs_refcount_btree.h"
+#include "xfs_extent_busy.h"
+#include "xfs_ag_resv.h"
+#include "xfs_trans_space.h"
+#include "scrub/xfs_scrub.h"
+#include "scrub/scrub.h"
+#include "scrub/common.h"
+#include "scrub/trace.h"
+#include "scrub/repair.h"
+
+/*
+ * Repair probe -- userspace uses this to probe if we're willing to repair a
+ * given mountpoint.
+ */
+int
+xfs_repair_probe(
+ struct xfs_scrub_context *sc)
+{
+ int error = 0;
+
+ if (xfs_scrub_should_terminate(sc, &error))
+ return error;
+
+ return 0;
+}
diff --git a/fs/xfs/scrub/repair.h b/fs/xfs/scrub/repair.h
new file mode 100644
index 0000000..660ab3a
--- /dev/null
+++ b/fs/xfs/scrub/repair.h
@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2018 Oracle. All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+#ifndef __XFS_SCRUB_REPAIR_H__
+#define __XFS_SCRUB_REPAIR_H__
+
+#ifdef CONFIG_XFS_ONLINE_REPAIR
+
+int xfs_repair_probe(struct xfs_scrub_context *sc);
+
+#else
+
+#define xfs_repair_probe (NULL)
+
+#endif /* CONFIG_XFS_ONLINE_REPAIR */
+
+#endif /* __XFS_SCRUB_REPAIR_H__ */
diff --git a/fs/xfs/scrub/scrub.c b/fs/xfs/scrub/scrub.c
index 26c7596..888ab2a 100644
--- a/fs/xfs/scrub/scrub.c
+++ b/fs/xfs/scrub/scrub.c
@@ -42,11 +42,16 @@
#include "xfs_refcount_btree.h"
#include "xfs_rmap.h"
#include "xfs_rmap_btree.h"
+#include "xfs_errortag.h"
+#include "xfs_error.h"
+#include "xfs_log.h"
+#include "xfs_trans_priv.h"
#include "scrub/xfs_scrub.h"
#include "scrub/scrub.h"
#include "scrub/common.h"
#include "scrub/trace.h"
#include "scrub/btree.h"
+#include "scrub/repair.h"
/*
* Online Scrub and Repair
@@ -120,6 +125,24 @@
* XCORRUPT flag; btree query function errors are noted by setting the
* XFAIL flag and deleting the cursor to prevent further attempts to
* cross-reference with a defective btree.
+ *
+ * If a piece of metadata proves corrupt or suboptimal, the userspace
+ * program can ask the kernel to apply some tender loving care (TLC) to
+ * the metadata object by setting the REPAIR flag and re-calling the
+ * scrub ioctl. "Corruption" is defined by metadata violating the
+ * on-disk specification; operations cannot continue if the violation is
+ * left untreated. It is possible for XFS to continue if an object is
+ * "suboptimal", however performance may be degraded. Repairs are
+ * usually performed by rebuilding the metadata entirely out of
+ * redundant metadata. Optimizing, on the other hand, can sometimes be
+ * done without rebuilding entire structures.
+ *
+ * Generally speaking, the repair code has the following code structure:
+ * Lock -> scrub -> repair -> commit -> re-lock -> re-scrub -> unlock.
+ * The first check helps us figure out if we need to rebuild or simply
+ * optimize the structure so that the rebuild knows what to do. The
+ * second check evaluates the completeness of the repair; that is what
+ * is reported to userspace.
*/
/*
@@ -155,7 +178,10 @@ xfs_scrub_teardown(
{
xfs_scrub_ag_free(sc, &sc->sa);
if (sc->tp) {
- xfs_trans_cancel(sc->tp);
+ if (error == 0 && (sc->sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR))
+ error = xfs_trans_commit(sc->tp);
+ else
+ xfs_trans_cancel(sc->tp);
sc->tp = NULL;
}
if (sc->ip) {
@@ -180,6 +206,7 @@ static const struct xfs_scrub_meta_ops meta_scrub_ops[] = {
.type = ST_NONE,
.setup = xfs_scrub_setup_fs,
.scrub = xfs_scrub_probe,
+ .repair = xfs_repair_probe,
},
[XFS_SCRUB_TYPE_SB] = { /* superblock */
.type = ST_PERAG,
@@ -379,15 +406,98 @@ xfs_scrub_validate_inputs(
if (!xfs_sb_version_hasextflgbit(&mp->m_sb))
goto out;
- /* We don't know how to repair anything yet. */
- if (sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR)
- goto out;
+ /*
+ * We only want to repair read-write v5+ filesystems. Defer the check
+ * for ops->repair until after our scrub confirms that we need to
+ * perform repairs so that we avoid failing due to not supporting
+ * repairing an object that doesn't need repairs.
+ */
+ if (sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR) {
+ error = -EOPNOTSUPP;
+ if (!xfs_sb_version_hascrc(&mp->m_sb))
+ goto out;
+
+ error = -EROFS;
+ if (mp->m_flags & XFS_MOUNT_RDONLY)
+ goto out;
+ }
error = 0;
out:
return error;
}
+/*
+ * Attempt to repair some metadata, if the metadata is corrupt and userspace
+ * told us to fix it. This function returns -EAGAIN to mean "re-run scrub",
+ * and will set *fixed to true if it thinks it repaired anything.
+ */
+STATIC int
+xfs_repair_attempt(
+ struct xfs_inode *ip,
+ struct xfs_scrub_context *sc,
+ bool *fixed)
+{
+ int error = 0;
+
+ trace_xfs_repair_attempt(ip, sc->sm, error);
+
+ /* Repair needed but not supported, just exit. */
+ if (!sc->ops->repair) {
+ error = -EOPNOTSUPP;
+ trace_xfs_repair_done(ip, sc->sm, error);
+ return error;
+ }
+
+ xfs_scrub_ag_btcur_free(&sc->sa);
+
+ /* Repair whatever's broken. */
+ error = sc->ops->repair(sc);
+ trace_xfs_repair_done(ip, sc->sm, error);
+ switch (error) {
+ case 0:
+ /*
+ * Repair succeeded. Commit the fixes and perform a second
+ * scrub so that we can tell userspace if we fixed the problem.
+ */
+ sc->sm->sm_flags &= ~XFS_SCRUB_FLAGS_OUT;
+ *fixed = true;
+ return -EAGAIN;
+ case -EDEADLOCK:
+ case -EAGAIN:
+ /* Tell the caller to try again having grabbed all the locks. */
+ if (!sc->try_harder) {
+ sc->try_harder = true;
+ return -EAGAIN;
+ }
+ /*
+ * We tried harder but still couldn't grab all the resources
+ * we needed to fix it. The corruption has not been fixed,
+ * so report back to userspace.
+ */
+ return -EFSCORRUPTED;
+ default:
+ return error;
+ }
+}
+
+/*
+ * Complain about unfixable problems in the filesystem. We don't log
+ * corruptions when IFLAG_REPAIR wasn't set on the assumption that the driver
+ * program is xfs_scrub, which will call back with IFLAG_REPAIR set if the
+ * administrator isn't running xfs_scrub in no-repairs mode.
+ *
+ * Use this helper function because _ratelimited silently declares a static
+ * structure to track rate limiting information.
+ */
+static void
+xfs_repair_failure(
+ struct xfs_mount *mp)
+{
+ xfs_alert_ratelimited(mp,
+"Corruption not fixed during online repair. Unmount and run xfs_repair.");
+}
+
/* Dispatch metadata scrubbing. */
int
xfs_scrub_metadata(
@@ -397,6 +507,7 @@ xfs_scrub_metadata(
struct xfs_scrub_context sc;
struct xfs_mount *mp = ip->i_mount;
bool try_harder = false;
+ bool already_fixed = false;
int error = 0;
BUILD_BUG_ON(sizeof(meta_scrub_ops) !=
@@ -446,9 +557,52 @@ xfs_scrub_metadata(
} else if (error)
goto out_teardown;
- if (sc.sm->sm_flags & (XFS_SCRUB_OFLAG_CORRUPT |
- XFS_SCRUB_OFLAG_XCORRUPT))
- xfs_alert_ratelimited(mp, "Corruption detected during scrub.");
+ if ((sc.sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR) && !already_fixed) {
+ bool needs_fix;
+
+ /* Let debug users force us into the repair routines. */
+ if (XFS_TEST_ERROR(false, mp, XFS_ERRTAG_FORCE_SCRUB_REPAIR))
+ sc.sm->sm_flags |= XFS_SCRUB_OFLAG_CORRUPT;
+
+ needs_fix = (sc.sm->sm_flags & (XFS_SCRUB_OFLAG_CORRUPT |
+ XFS_SCRUB_OFLAG_XCORRUPT |
+ XFS_SCRUB_OFLAG_PREEN));
+ /*
+ * If userspace asked for a repair but it wasn't necessary,
+ * report that back to userspace.
+ */
+ if (!needs_fix) {
+ sc.sm->sm_flags |= XFS_SCRUB_OFLAG_NO_REPAIR_NEEDED;
+ goto out_nofix;
+ }
+
+ /*
+ * If it's broken, userspace wants us to fix it, and we haven't
+ * already tried to fix it, then attempt a repair.
+ */
+ error = xfs_repair_attempt(ip, &sc, &already_fixed);
+ if (error == -EAGAIN) {
+ if (sc.try_harder)
+ try_harder = true;
+ error = xfs_scrub_teardown(&sc, ip, 0);
+ if (error) {
+ xfs_repair_failure(mp);
+ goto out;
+ }
+ goto retry_op;
+ }
+ }
+
+out_nofix:
+ /*
+ * Userspace asked us to repair something, we repaired it, rescanned
+ * it, and the rescan says it's still broken. Scream about this in
+ * the system logs.
+ */
+ if ((sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR) &&
+ (sm->sm_flags & (XFS_SCRUB_OFLAG_CORRUPT |
+ XFS_SCRUB_OFLAG_XCORRUPT)))
+ xfs_repair_failure(mp);
out_teardown:
error = xfs_scrub_teardown(&sc, ip, error);
diff --git a/fs/xfs/scrub/scrub.h b/fs/xfs/scrub/scrub.h
index 0d92af8..9ab8ef8 100644
--- a/fs/xfs/scrub/scrub.h
+++ b/fs/xfs/scrub/scrub.h
@@ -38,6 +38,9 @@ struct xfs_scrub_meta_ops {
/* Examine metadata for errors. */
int (*scrub)(struct xfs_scrub_context *);
+ /* Repair or optimize the metadata. */
+ int (*repair)(struct xfs_scrub_context *);
+
/* Decide if we even have this piece of metadata. */
bool (*has)(struct xfs_sb *);
diff --git a/fs/xfs/xfs_error.c b/fs/xfs/xfs_error.c
index a63f508..7975634 100644
--- a/fs/xfs/xfs_error.c
+++ b/fs/xfs/xfs_error.c
@@ -61,6 +61,7 @@ static unsigned int xfs_errortag_random_default[] = {
XFS_RANDOM_LOG_BAD_CRC,
XFS_RANDOM_LOG_ITEM_PIN,
XFS_RANDOM_BUF_LRU_REF,
+ XFS_RANDOM_FORCE_SCRUB_REPAIR,
};
struct xfs_errortag_attr {
@@ -167,6 +168,7 @@ XFS_ERRORTAG_ATTR_RW(drop_writes, XFS_ERRTAG_DROP_WRITES);
XFS_ERRORTAG_ATTR_RW(log_bad_crc, XFS_ERRTAG_LOG_BAD_CRC);
XFS_ERRORTAG_ATTR_RW(log_item_pin, XFS_ERRTAG_LOG_ITEM_PIN);
XFS_ERRORTAG_ATTR_RW(buf_lru_ref, XFS_ERRTAG_BUF_LRU_REF);
+XFS_ERRORTAG_ATTR_RW(force_repair, XFS_ERRTAG_FORCE_SCRUB_REPAIR);
static struct attribute *xfs_errortag_attrs[] = {
XFS_ERRORTAG_ATTR_LIST(noerror),
@@ -201,6 +203,7 @@ static struct attribute *xfs_errortag_attrs[] = {
XFS_ERRORTAG_ATTR_LIST(log_bad_crc),
XFS_ERRORTAG_ATTR_LIST(log_item_pin),
XFS_ERRORTAG_ATTR_LIST(buf_lru_ref),
+ XFS_ERRORTAG_ATTR_LIST(force_repair),
NULL,
};
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