From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
When scanning a metadata btree block, cross-reference the block location
with the free space btree and the reverse mapping btree to ensure that
the rmapbt knows about the block and the bnobt does not. Add a
mechanism to defer checks when we happen to be scanning the bnobt/rmapbt
itself because it's less efficient to repeatedly clone and destroy the
cursor.
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
fs/xfs/scrub/btree.c | 92 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 92 insertions(+)
diff --git a/fs/xfs/scrub/btree.c b/fs/xfs/scrub/btree.c
index 36cff8f..9151499 100644
--- a/fs/xfs/scrub/btree.c
+++ b/fs/xfs/scrub/btree.c
@@ -362,6 +362,80 @@ xfs_scrub_btree_block_check_siblings(
return error;
}
+struct check_owner {
+ struct list_head list;
+ xfs_daddr_t daddr;
+ int level;
+};
+
+/*
+ * Make sure this btree block isn't in the free list and that there's
+ * an rmap record for it.
+ */
+STATIC int
+xfs_scrub_btree_check_block_owner(
+ struct xfs_scrub_btree *bs,
+ int level,
+ xfs_daddr_t daddr)
+{
+ struct xfs_scrub_ag sa = { 0 };
+ struct xfs_scrub_ag *psa;
+ xfs_agnumber_t agno;
+ int error = 0;
+
+ agno = xfs_daddr_to_agno(bs->cur->bc_mp, daddr);
+
+ if (bs->cur->bc_flags & XFS_BTREE_LONG_PTRS) {
+ error = xfs_scrub_ag_init(bs->sc, agno, &sa);
+ if (!xfs_scrub_btree_xref_process_error(bs->sc, bs->cur,
+ level, &error))
+ return error;
+ psa = &sa;
+ } else {
+ psa = &bs->sc->sa;
+ }
+
+ if (psa == &sa)
+ xfs_scrub_ag_free(bs->sc, &sa);
+
+ return error;
+}
+
+/* Check the owner of a btree block. */
+STATIC int
+xfs_scrub_btree_check_owner(
+ struct xfs_scrub_btree *bs,
+ int level,
+ struct xfs_buf *bp)
+{
+ struct xfs_btree_cur *cur = bs->cur;
+ struct check_owner *co;
+
+ if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) && bp == NULL)
+ return 0;
+
+ /*
+ * We want to cross-reference each btree block with the bnobt
+ * and the rmapbt. We cannot cross-reference the bnobt or
+ * rmapbt while scanning the bnobt or rmapbt, respectively,
+ * because we cannot alter the cursor and we'd prefer not to
+ * duplicate cursors. Therefore, save the buffer daddr for
+ * later scanning.
+ */
+ if (cur->bc_btnum == XFS_BTNUM_BNO || cur->bc_btnum == XFS_BTNUM_RMAP) {
+ co = kmem_alloc(sizeof(struct check_owner),
+ KM_MAYFAIL | KM_NOFS);
+ if (!co)
+ return -ENOMEM;
+ co->level = level;
+ co->daddr = XFS_BUF_ADDR(bp);
+ list_add_tail(&co->list, &bs->to_check);
+ return 0;
+ }
+
+ return xfs_scrub_btree_check_block_owner(bs, level, XFS_BUF_ADDR(bp));
+}
+
/*
* Grab and scrub a btree block given a btree pointer. Returns block
* and buffer pointers (if applicable) if they're ok to use.
@@ -398,6 +472,14 @@ xfs_scrub_btree_get_block(
}
/*
+ * Check the block's owner; this function absorbs error codes
+ * for us.
+ */
+ error = xfs_scrub_btree_check_owner(bs, level, *pbp);
+ if (error)
+ return error;
+
+ /*
* Check the block's siblings; this function absorbs error codes
* for us.
*/
@@ -468,6 +550,8 @@ xfs_scrub_btree(
struct xfs_btree_block *block;
int level;
struct xfs_buf *bp;
+ struct check_owner *co;
+ struct check_owner *n;
int i;
int error = 0;
@@ -559,6 +643,14 @@ xfs_scrub_btree(
}
out:
+ /* Process deferred owner checks on btree blocks. */
+ list_for_each_entry_safe(co, n, &bs.to_check, list) {
+ if (!error)
+ error = xfs_scrub_btree_check_block_owner(&bs,
+ co->level, co->daddr);
+ list_del(&co->list);
+ kmem_free(co);
+ }
return error;
}
--
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