[PATCH 36/67] xfs: repair refcount btrees

Darrick J. Wong
2024-03-13T02:02:25Z

From: Darrick J. Wong <djwong@kernel.org>

Source kernel commit: 9099cd38002f8029c9a1da08e6832d1cd18e8451

Reconstruct the refcount data from the rmap btree.

Link: https://docs.kernel.org/filesystems/xfs-online-fsck-design.html#case-study-rebuilding-the-space-reference-counts
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
libxfs/xfs_ag.h | 1 +
libxfs/xfs_btree.c | 26 ++++++++++++++++++++++++++
libxfs/xfs_btree.h | 2 ++
libxfs/xfs_refcount.c | 8 +++-----
libxfs/xfs_refcount.h | 2 +-
libxfs/xfs_refcount_btree.c | 13 ++++++++++++-
6 files changed, 45 insertions(+), 7 deletions(-)

diff --git a/libxfs/xfs_ag.h b/libxfs/xfs_ag.h
index f16cb7a174d4..67c3260ee789 100644
--- a/libxfs/xfs_ag.h
+++ b/libxfs/xfs_ag.h
@@ -87,6 +87,7 @@ struct xfs_perag {
* verifiers while rebuilding the AG btrees.
*/
uint8_t pagf_repair_levels[XFS_BTNUM_AGF];
+ uint8_t pagf_repair_refcount_level;
#endif

spinlock_t pag_state_lock;
diff --git a/libxfs/xfs_btree.c b/libxfs/xfs_btree.c
index 97962fc16ec4..0022bb641bee 100644
--- a/libxfs/xfs_btree.c
+++ b/libxfs/xfs_btree.c
@@ -5209,3 +5209,29 @@ xfs_btree_destroy_cur_caches(void)
xfs_rmapbt_destroy_cur_cache();
xfs_refcountbt_destroy_cur_cache();
}
+
+/* Move the btree cursor before the first record. */
+int
+xfs_btree_goto_left_edge(
+ struct xfs_btree_cur *cur)
+{
+ int stat = 0;
+ int error;
+
+ memset(&cur->bc_rec, 0, sizeof(cur->bc_rec));
+ error = xfs_btree_lookup(cur, XFS_LOOKUP_LE, &stat);
+ if (error)
+ return error;
+ if (!stat)
+ return 0;
+
+ error = xfs_btree_decrement(cur, 0, &stat);
+ if (error)
+ return error;
+ if (stat != 0) {
+ ASSERT(0);
+ return -EFSCORRUPTED;
+ }
+
+ return 0;
+}
diff --git a/libxfs/xfs_btree.h b/libxfs/xfs_btree.h
index e0875cec4939..d906324e25c8 100644
--- a/libxfs/xfs_btree.h
+++ b/libxfs/xfs_btree.h
@@ -738,4 +738,6 @@ xfs_btree_alloc_cursor(
int __init xfs_btree_init_cur_caches(void);
void xfs_btree_destroy_cur_caches(void);

+int xfs_btree_goto_left_edge(struct xfs_btree_cur *cur);
+
#endif /* __XFS_BTREE_H__ */
diff --git a/libxfs/xfs_refcount.c b/libxfs/xfs_refcount.c
index 45f8134e4314..3377fac1283b 100644
--- a/libxfs/xfs_refcount.c
+++ b/libxfs/xfs_refcount.c
@@ -122,11 +122,9 @@ xfs_refcount_btrec_to_irec(
/* Simple checks for refcount records. */
xfs_failaddr_t
xfs_refcount_check_irec(
- struct xfs_btree_cur *cur,
+ struct xfs_perag *pag,
const struct xfs_refcount_irec *irec)
{
- struct xfs_perag *pag = cur->bc_ag.pag;
-
if (irec->rc_blockcount == 0 || irec->rc_blockcount > MAXREFCEXTLEN)
return __this_address;

@@ -178,7 +176,7 @@ xfs_refcount_get_rec(
return error;

xfs_refcount_btrec_to_irec(rec, irec);
- fa = xfs_refcount_check_irec(cur, irec);
+ fa = xfs_refcount_check_irec(cur->bc_ag.pag, irec);
if (fa)
return xfs_refcount_complain_bad_rec(cur, fa, irec);

@@ -1898,7 +1896,7 @@ xfs_refcount_recover_extent(
INIT_LIST_HEAD(&rr->rr_list);
xfs_refcount_btrec_to_irec(rec, &rr->rr_rrec);

- if (xfs_refcount_check_irec(cur, &rr->rr_rrec) != NULL ||
+ if (xfs_refcount_check_irec(cur->bc_ag.pag, &rr->rr_rrec) != NULL ||
XFS_IS_CORRUPT(cur->bc_mp,
rr->rr_rrec.rc_domain != XFS_REFC_DOMAIN_COW)) {
kfree(rr);
diff --git a/libxfs/xfs_refcount.h b/libxfs/xfs_refcount.h
index 783cd89ca195..5c207f1c619c 100644
--- a/libxfs/xfs_refcount.h
+++ b/libxfs/xfs_refcount.h
@@ -117,7 +117,7 @@ extern int xfs_refcount_has_records(struct xfs_btree_cur *cur,
union xfs_btree_rec;
extern void xfs_refcount_btrec_to_irec(const union xfs_btree_rec *rec,
struct xfs_refcount_irec *irec);
-xfs_failaddr_t xfs_refcount_check_irec(struct xfs_btree_cur *cur,
+xfs_failaddr_t xfs_refcount_check_irec(struct xfs_perag *pag,
const struct xfs_refcount_irec *irec);
extern int xfs_refcount_insert(struct xfs_btree_cur *cur,
struct xfs_refcount_irec *irec, int *stat);
diff --git a/libxfs/xfs_refcount_btree.c b/libxfs/xfs_refcount_btree.c
index bc8bd867eee7..ac1c3ab868e0 100644
--- a/libxfs/xfs_refcount_btree.c
+++ b/libxfs/xfs_refcount_btree.c
@@ -225,7 +225,18 @@ xfs_refcountbt_verify(

level = be16_to_cpu(block->bb_level);
if (pag && xfs_perag_initialised_agf(pag)) {
- if (level >= pag->pagf_refcount_level)
+ unsigned int maxlevel = pag->pagf_refcount_level;
+
+#ifdef CONFIG_XFS_ONLINE_REPAIR
+ /*
+ * Online repair could be rewriting the refcount btree, so
+ * we'll validate against the larger of either tree while this
+ * is going on.
+ */
+ maxlevel = max_t(unsigned int, maxlevel,
+ pag->pagf_repair_refcount_level);
+#endif
+ if (level >= maxlevel)
return __this_address;
} else if (level >= mp->m_refc_maxlevels)
return __this_address;