xfs: standardize ondisk to incore conversion for refcount btrees

Create a xfs_refcount_check_irec function to detect corruption in btree
records.  Fix all xfs_refcount_btrec_to_irec callsites to call the new
helper and bubble up corruption reports.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

Author: Darrick J. Wong

fs/xfs/libxfs/xfs_refcount.c

@@ -120,6 +120,30 @@ xfs_refcount_btrec_to_irec(
 	irec->rc_refcount = be32_to_cpu(rec->refc.rc_refcount);
 }
 
+/* Simple checks for refcount records. */
+xfs_failaddr_t
+xfs_refcount_check_irec(
+	struct xfs_btree_cur		*cur,
+	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;
+
+	if (!xfs_refcount_check_domain(irec))
+		return __this_address;
+
+	/* check for valid extent range, including overflow */
+	if (!xfs_verify_agbext(pag, irec->rc_startblock, irec->rc_blockcount))
+		return __this_address;
+
+	if (irec->rc_refcount == 0 || irec->rc_refcount > MAXREFCOUNT)
+		return __this_address;
+
+	return NULL;
+}
+
 /*
  * Get the data from the pointed-to record.
  */
@@ -132,33 +156,25 @@ xfs_refcount_get_rec(
 	struct xfs_mount		*mp = cur->bc_mp;
 	struct xfs_perag		*pag = cur->bc_ag.pag;
 	union xfs_btree_rec		*rec;
+	xfs_failaddr_t			fa;
 	int				error;
 
 	error = xfs_btree_get_rec(cur, &rec, stat);
 	if (error || !*stat)
 		return error;
 
 	xfs_refcount_btrec_to_irec(rec, irec);
-	if (irec->rc_blockcount == 0 || irec->rc_blockcount > MAXREFCEXTLEN)
-		goto out_bad_rec;
-
-	if (!xfs_refcount_check_domain(irec))
-		goto out_bad_rec;
-
-	/* check for valid extent range, including overflow */
-	if (!xfs_verify_agbext(pag, irec->rc_startblock, irec->rc_blockcount))
-		goto out_bad_rec;
-
-	if (irec->rc_refcount == 0 || irec->rc_refcount > MAXREFCOUNT)
+	fa = xfs_refcount_check_irec(cur, irec);
+	if (fa)
 		goto out_bad_rec;
 
 	trace_xfs_refcount_get(cur->bc_mp, pag->pag_agno, irec);
 	return 0;
 
 out_bad_rec:
 	xfs_warn(mp,
-		"Refcount BTree record corruption in AG %d detected!",
-		pag->pag_agno);
+		"Refcount BTree record corruption in AG %d detected at %pS!",
+		pag->pag_agno, fa);
 	xfs_warn(mp,
 		"Start block 0x%x, block count 0x%x, references 0x%x",
 		irec->rc_startblock, irec->rc_blockcount, irec->rc_refcount);
@@ -1871,7 +1887,8 @@ xfs_refcount_recover_extent(
 	INIT_LIST_HEAD(&rr->rr_list);
 	xfs_refcount_btrec_to_irec(rec, &rr->rr_rrec);
 
-	if (XFS_IS_CORRUPT(cur->bc_mp,
+	if (xfs_refcount_check_irec(cur, &rr->rr_rrec) != NULL ||
+	    XFS_IS_CORRUPT(cur->bc_mp,
 			   rr->rr_rrec.rc_domain != XFS_REFC_DOMAIN_COW)) {
 		kfree(rr);
 		return -EFSCORRUPTED;

fs/xfs/libxfs/xfs_refcount.h

@@ -117,6 +117,8 @@ extern int xfs_refcount_has_record(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,
+		const struct xfs_refcount_irec *irec);
 extern int xfs_refcount_insert(struct xfs_btree_cur *cur,
 		struct xfs_refcount_irec *irec, int *stat);
 

fs/xfs/scrub/refcount.c

@@ -340,24 +340,16 @@ xchk_refcountbt_rec(
 {
 	struct xfs_refcount_irec irec;
 	xfs_agblock_t		*cow_blocks = bs->private;
-	struct xfs_perag	*pag = bs->cur->bc_ag.pag;
 
 	xfs_refcount_btrec_to_irec(rec, &irec);
-
-	/* Check the domain and refcount are not incompatible. */
-	if (!xfs_refcount_check_domain(&irec))
+	if (xfs_refcount_check_irec(bs->cur, &irec) != NULL) {
 		xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
+		return 0;
+	}
 
 	if (irec.rc_domain == XFS_REFC_DOMAIN_COW)
 		(*cow_blocks) += irec.rc_blockcount;
 
-	/* Check the extent. */
-	if (!xfs_verify_agbext(pag, irec.rc_startblock, irec.rc_blockcount))
-		xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
-
-	if (irec.rc_refcount == 0)
-		xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
-
 	xchk_refcountbt_xref(bs->sc, &irec);
 
 	return 0;