Plumb in the pieces necessary to make the "repair" subfunction of
the scrub ioctl actually work.
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
fs/xfs/xfs_error.h | 4 ++
fs/xfs/xfs_scrub.c | 95 +++++++++++++++++++++++++++++++++++++++++++++++++---
2 files changed, 93 insertions(+), 6 deletions(-)
diff --git a/fs/xfs/xfs_error.h b/fs/xfs/xfs_error.h
index 05f8666..4c22d9a 100644
--- a/fs/xfs/xfs_error.h
+++ b/fs/xfs/xfs_error.h
@@ -96,7 +96,8 @@ extern void xfs_verifier_error(struct xfs_buf *bp);
#define XFS_ERRTAG_REFCOUNT_FINISH_ONE 25
#define XFS_ERRTAG_BMAP_FINISH_ONE 26
#define XFS_ERRTAG_AG_RESV_CRITICAL 27
-#define XFS_ERRTAG_MAX 28
+#define XFS_ERRTAG_FORCE_SCRUB_REPAIR 28
+#define XFS_ERRTAG_MAX 29
/*
* Random factors for above tags, 1 means always, 2 means 1/2 time, etc.
@@ -129,6 +130,7 @@ extern void xfs_verifier_error(struct xfs_buf *bp);
#define XFS_RANDOM_REFCOUNT_FINISH_ONE 1
#define XFS_RANDOM_BMAP_FINISH_ONE 1
#define XFS_RANDOM_AG_RESV_CRITICAL 4
+#define XFS_RANDOM_FORCE_SCRUB_REPAIR 1
#ifdef DEBUG
extern int xfs_error_test_active;
diff --git a/fs/xfs/xfs_scrub.c b/fs/xfs/xfs_scrub.c
index ca1bc8b..7e03c54 100644
--- a/fs/xfs/xfs_scrub.c
+++ b/fs/xfs/xfs_scrub.c
@@ -54,6 +54,7 @@
#include "xfs_attr_leaf.h"
#include "xfs_attr.h"
#include "xfs_symlink.h"
+#include "xfs_error.h"
#include <linux/posix_acl_xattr.h>
#include <linux/xattr.h>
@@ -121,6 +122,23 @@
* the metadata is correct but otherwise suboptimal, there's a "preen"
* flag to signal that. Finally, if we were unable to access a data
* structure to perform cross-referencing, we can signal that as well.
+ *
+ * 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. "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.
*/
/* Buffer pointers and btree cursors for an entire AG. */
@@ -171,6 +189,24 @@ struct xfs_scrub_context {
struct xfs_scrub_ag sa;
};
+/* Fix something if errors were detected and the user asked for repair. */
+static inline bool
+xfs_scrub_should_fix(
+ struct xfs_scrub_metadata *sm)
+{
+ return (sm->sm_flags & XFS_SCRUB_FLAG_REPAIR) &&
+ (sm->sm_flags & (XFS_SCRUB_FLAG_CORRUPT | XFS_SCRUB_FLAG_PREEN));
+}
+
+/* Clear the corruption status flags. */
+static inline bool
+xfs_scrub_reset_corruption_flags(
+ struct xfs_scrub_metadata *sm)
+{
+ return sm->sm_flags &= ~(XFS_SCRUB_FLAG_CORRUPT | XFS_SCRUB_FLAG_PREEN |
+ XFS_SCRUB_FLAG_XREF_FAIL);
+}
+
/*
* Grab a transaction. If we're going to repair something, we need to
* ensure there's enough reservation to make all the changes. If not,
@@ -186,6 +222,9 @@ xfs_scrub_trans_alloc(
uint flags,
struct xfs_trans **tpp)
{
+ if (sm->sm_flags & XFS_SCRUB_FLAG_REPAIR)
+ return xfs_trans_alloc(mp, resp, blocks, rtextents, flags, tpp);
+
return xfs_trans_alloc_empty(mp, tpp);
}
@@ -1472,7 +1511,10 @@ xfs_scrub_teardown(
if (sc->ag_lock.agmask != sc->ag_lock.__agmask)
kmem_free(sc->ag_lock.agmask);
sc->ag_lock.agmask = NULL;
- xfs_trans_cancel(sc->tp);
+ if (error == 0 && (sc->sm->sm_flags & XFS_SCRUB_FLAG_REPAIR))
+ error = xfs_trans_commit(sc->tp);
+ else
+ xfs_trans_cancel(sc->tp);
sc->tp = NULL;
if (sc->ip != NULL) {
xfs_iunlock(sc->ip, XFS_ILOCK_EXCL);
@@ -4673,6 +4715,7 @@ xfs_scrub_metadata(
struct xfs_mount *mp = ip->i_mount;
const struct xfs_scrub_meta_fns *fns;
bool deadlocked = false;
+ bool already_fixed = false;
int error = 0;
trace_xfs_scrub(ip, sm->sm_type, sm->sm_agno, sm->sm_ino, sm->sm_gen,
@@ -4686,12 +4729,18 @@ xfs_scrub_metadata(
sm->sm_flags &= ~XFS_SCRUB_FLAGS_OUT;
if (sm->sm_flags & ~XFS_SCRUB_FLAGS_IN)
goto out;
- if (sm->sm_flags & XFS_SCRUB_FLAG_REPAIR)
- goto out;
error = -ENOTTY;
if (sm->sm_type > XFS_SCRUB_TYPE_MAX)
goto out;
fns = &meta_scrub_fns[sm->sm_type];
+ if ((sm->sm_flags & XFS_SCRUB_FLAG_REPAIR) &&
+ (fns->repair == NULL || !xfs_sb_version_hascrc(&mp->m_sb)))
+ goto out;
+
+ error = -EROFS;
+ if ((sm->sm_flags & XFS_SCRUB_FLAG_REPAIR) &&
+ (mp->m_flags & XFS_MOUNT_RDONLY))
+ goto out;
/* Do we even have this type of metadata? */
error = -ENOENT;
@@ -4731,8 +4780,44 @@ xfs_scrub_metadata(
} else if (error)
goto out_teardown;
- if (sm->sm_flags & XFS_SCRUB_FLAG_CORRUPT)
- xfs_alert_ratelimited(mp, "Corruption detected during scrub.");
+ /* Let debug users force us into the repair routines. */
+ if ((sm->sm_flags & XFS_SCRUB_FLAG_REPAIR) && !already_fixed &&
+ XFS_TEST_ERROR(false, mp,
+ XFS_ERRTAG_FORCE_SCRUB_REPAIR,
+ XFS_RANDOM_FORCE_SCRUB_REPAIR)) {
+ sm->sm_flags |= XFS_SCRUB_FLAG_CORRUPT;
+ }
+
+ if (!already_fixed && xfs_scrub_should_fix(sm)) {
+ xfs_scrub_ag_btcur_free(&sc.sa);
+
+ /* Ok, something's wrong. Repair it. */
+ error = fns->repair(&sc);
+ if (error)
+ goto out_teardown;
+
+ /*
+ * Commit the fixes and perform a second dry-run scrub
+ * so that we can tell userspace if we fixed the problem.
+ */
+ error = xfs_scrub_teardown(&sc, ip, error);
+ if (error)
+ goto out_teardown;
+ xfs_scrub_reset_corruption_flags(sm);
+ already_fixed = true;
+ goto retry_op;
+ }
+
+ if (sm->sm_flags & XFS_SCRUB_FLAG_CORRUPT) {
+ char *errstr;
+
+ if (sm->sm_flags & XFS_SCRUB_FLAG_REPAIR)
+ errstr = "Corruption not fixed during online repair. "
+ "Unmount and run xfs_repair.";
+ else
+ errstr = "Corruption detected during scrub.";
+ xfs_alert_ratelimited(mp, errstr);
+ }
out_teardown:
error = xfs_scrub_teardown(&sc, ip, error);
--
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