xfs: standardize ondisk to incore conversion for inode btrees

Create a xfs_inobt_check_irec function to detect corruption in btree
records.  Fix all xfs_inobt_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>

fs/xfs/libxfs/xfs_ialloc.c

@@ -95,6 +95,33 @@ xfs_inobt_btrec_to_irec(
 	irec->ir_free = be64_to_cpu(rec->inobt.ir_free);
 }
 
+/* Simple checks for inode records. */
+xfs_failaddr_t
+xfs_inobt_check_irec(
+	struct xfs_btree_cur			*cur,
+	const struct xfs_inobt_rec_incore	*irec)
+{
+	uint64_t			realfree;
+
+	if (!xfs_verify_agino(cur->bc_ag.pag, irec->ir_startino))
+		return __this_address;
+	if (irec->ir_count < XFS_INODES_PER_HOLEMASK_BIT ||
+	    irec->ir_count > XFS_INODES_PER_CHUNK)
+		return __this_address;
+	if (irec->ir_freecount > XFS_INODES_PER_CHUNK)
+		return __this_address;
+
+	/* if there are no holes, return the first available offset */
+	if (!xfs_inobt_issparse(irec->ir_holemask))
+		realfree = irec->ir_free;
+	else
+		realfree = irec->ir_free & xfs_inobt_irec_to_allocmask(irec);
+	if (hweight64(realfree) != irec->ir_freecount)
+		return __this_address;
+
+	return NULL;
+}
+
 /*
  * Get the data from the pointed-to record.
  */
@@ -106,38 +133,25 @@ xfs_inobt_get_rec(
 {
 	struct xfs_mount		*mp = cur->bc_mp;
 	union xfs_btree_rec		*rec;
+	xfs_failaddr_t			fa;
 	int				error;
-	uint64_t			realfree;
 
 	error = xfs_btree_get_rec(cur, &rec, stat);
 	if (error || *stat == 0)
 		return error;
 
 	xfs_inobt_btrec_to_irec(mp, rec, irec);
-
-	if (!xfs_verify_agino(cur->bc_ag.pag, irec->ir_startino))
-		goto out_bad_rec;
-	if (irec->ir_count < XFS_INODES_PER_HOLEMASK_BIT ||
-	    irec->ir_count > XFS_INODES_PER_CHUNK)
-		goto out_bad_rec;
-	if (irec->ir_freecount > XFS_INODES_PER_CHUNK)
-		goto out_bad_rec;
-
-	/* if there are no holes, return the first available offset */
-	if (!xfs_inobt_issparse(irec->ir_holemask))
-		realfree = irec->ir_free;
-	else
-		realfree = irec->ir_free & xfs_inobt_irec_to_allocmask(irec);
-	if (hweight64(realfree) != irec->ir_freecount)
+	fa = xfs_inobt_check_irec(cur, irec);
+	if (fa)
 		goto out_bad_rec;
 
 	return 0;
 
 out_bad_rec:
 	xfs_warn(mp,
-		"%s Inode BTree record corruption in AG %d detected!",
+		"%s Inode BTree record corruption in AG %d detected at %pS!",
 		cur->bc_btnum == XFS_BTNUM_INO ? "Used" : "Free",
-		cur->bc_ag.pag->pag_agno);
+		cur->bc_ag.pag->pag_agno, fa);
 	xfs_warn(mp,
 "start inode 0x%x, count 0x%x, free 0x%x freemask 0x%llx, holemask 0x%x",
 		irec->ir_startino, irec->ir_count, irec->ir_freecount,
@@ -2690,6 +2704,9 @@ xfs_ialloc_count_inodes_rec(
 	struct xfs_ialloc_count_inodes	*ci = priv;
 
 	xfs_inobt_btrec_to_irec(cur->bc_mp, rec, &irec);
+	if (xfs_inobt_check_irec(cur, &irec) != NULL)
+		return -EFSCORRUPTED;
+
 	ci->count += irec.ir_count;
 	ci->freecount += irec.ir_freecount;
 

fs/xfs/libxfs/xfs_ialloc.h

@@ -93,6 +93,8 @@ union xfs_btree_rec;
 void xfs_inobt_btrec_to_irec(struct xfs_mount *mp,
 		const union xfs_btree_rec *rec,
 		struct xfs_inobt_rec_incore *irec);
+xfs_failaddr_t xfs_inobt_check_irec(struct xfs_btree_cur *cur,
+		const struct xfs_inobt_rec_incore *irec);
 int xfs_ialloc_has_inodes_at_extent(struct xfs_btree_cur *cur,
 		xfs_agblock_t bno, xfs_extlen_t len, bool *exists);
 int xfs_ialloc_has_inode_record(struct xfs_btree_cur *cur, xfs_agino_t low,

fs/xfs/libxfs/xfs_ialloc_btree.c

@@ -608,7 +608,7 @@ xfs_iallocbt_maxlevels_ondisk(void)
  */
 uint64_t
 xfs_inobt_irec_to_allocmask(
-	struct xfs_inobt_rec_incore	*rec)
+	const struct xfs_inobt_rec_incore	*rec)
 {
 	uint64_t			bitmap = 0;
 	uint64_t			inodespbit;

fs/xfs/libxfs/xfs_ialloc_btree.h

@@ -53,7 +53,7 @@ struct xfs_btree_cur *xfs_inobt_stage_cursor(struct xfs_perag *pag,
 extern int xfs_inobt_maxrecs(struct xfs_mount *, int, int);
 
 /* ir_holemask to inode allocation bitmap conversion */
-uint64_t xfs_inobt_irec_to_allocmask(struct xfs_inobt_rec_incore *);
+uint64_t xfs_inobt_irec_to_allocmask(const struct xfs_inobt_rec_incore *irec);
 
 #if defined(DEBUG) || defined(XFS_WARN)
 int xfs_inobt_rec_check_count(struct xfs_mount *,

fs/xfs/scrub/ialloc.c

@@ -119,15 +119,6 @@ xchk_iallocbt_chunk(
 	return true;
 }
 
-/* Count the number of free inodes. */
-static unsigned int
-xchk_iallocbt_freecount(
-	xfs_inofree_t			freemask)
-{
-	BUILD_BUG_ON(sizeof(freemask) != sizeof(__u64));
-	return hweight64(freemask);
-}
-
 /*
  * Check that an inode's allocation status matches ir_free in the inobt
  * record.  First we try querying the in-core inode state, and if the inode
@@ -431,24 +422,17 @@ xchk_iallocbt_rec(
 	int				holecount;
 	int				i;
 	int				error = 0;
-	unsigned int			real_freecount;
 	uint16_t			holemask;
 
 	xfs_inobt_btrec_to_irec(mp, rec, &irec);
-
-	if (irec.ir_count > XFS_INODES_PER_CHUNK ||
-	    irec.ir_freecount > XFS_INODES_PER_CHUNK)
-		xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
-
-	real_freecount = irec.ir_freecount +
-			(XFS_INODES_PER_CHUNK - irec.ir_count);
-	if (real_freecount != xchk_iallocbt_freecount(irec.ir_free))
+	if (xfs_inobt_check_irec(bs->cur, &irec) != NULL) {
 		xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
+		return 0;
+	}
 
 	agino = irec.ir_startino;
 	/* Record has to be properly aligned within the AG. */
-	if (!xfs_verify_agino(pag, agino) ||
-	    !xfs_verify_agino(pag, agino + XFS_INODES_PER_CHUNK - 1)) {
+	if (!xfs_verify_agino(pag, agino + XFS_INODES_PER_CHUNK - 1)) {
 		xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
 		goto out;
 	}