xfs: track the number of blocks in each buftarg

Add a bt_nr_sectors to track the number of sector in each buftarg, and
replace the check that hard codes sb_dblock in xfs_buf_map_verify with
this new value so that it is correct for non-ddev buftargs.  The
RT buftarg only has a superblock in the first block, so it is unlikely
to trigger this, or are we likely to ever have enough blocks in the
in-memory buftargs, but we might as well get the check right.

Fixes: 10616b806d1d ("xfs: fix _xfs_buf_find oops on blocks beyond the filesystem end")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>

1 files changed, 23 insertions, 19 deletions

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index 8360e77b3215..773d959965dc 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -387,8 +387,6 @@ xfs_buf_map_verify(
 	struct xfs_buftarg	*btp,
 	struct xfs_buf_map	*map)
 {
-	xfs_daddr_t		eofs;
-
 	/* Check for IOs smaller than the sector size / not sector aligned */
 	ASSERT(!(BBTOB(map->bm_len) < btp->bt_meta_sectorsize));
 	ASSERT(!(BBTOB(map->bm_bn) & (xfs_off_t)btp->bt_meta_sectormask));
@@ -397,11 +395,10 @@ xfs_buf_map_verify(
 	 * Corrupted block numbers can get through to here, unfortunately, so we
 	 * have to check that the buffer falls within the filesystem bounds.
 	 */
-	eofs = XFS_FSB_TO_BB(btp->bt_mount, btp->bt_mount->m_sb.sb_dblocks);
-	if (map->bm_bn < 0 || map->bm_bn >= eofs) {
+	if (map->bm_bn < 0 || map->bm_bn >= btp->bt_nr_sectors) {
 		xfs_alert(btp->bt_mount,
 			  "%s: daddr 0x%llx out of range, EOFS 0x%llx",
-			  __func__, map->bm_bn, eofs);
+			  __func__, map->bm_bn, btp->bt_nr_sectors);
 		WARN_ON(1);
 		return -EFSCORRUPTED;
 	}
@@ -1720,26 +1717,30 @@ xfs_configure_buftarg_atomic_writes(
 int
 xfs_configure_buftarg(
 	struct xfs_buftarg	*btp,
-	unsigned int		sectorsize)
+	unsigned int		sectorsize,
+	xfs_rfsblock_t		nr_blocks)
 {
-	int			error;
+	struct xfs_mount	*mp = btp->bt_mount;
 
-	ASSERT(btp->bt_bdev != NULL);
+	if (btp->bt_bdev) {
+		int		error;
 
-	/* Set up metadata sector size info */
-	btp->bt_meta_sectorsize = sectorsize;
-	btp->bt_meta_sectormask = sectorsize - 1;
+		error = bdev_validate_blocksize(btp->bt_bdev, sectorsize);
+		if (error) {
+			xfs_warn(mp,
+				"Cannot use blocksize %u on device %pg, err %d",
+				sectorsize, btp->bt_bdev, error);
+			return -EINVAL;
+		}
 
-	error = bdev_validate_blocksize(btp->bt_bdev, sectorsize);
-	if (error) {
-		xfs_warn(btp->bt_mount,
-			"Cannot use blocksize %u on device %pg, err %d",
-			sectorsize, btp->bt_bdev, error);
-		return -EINVAL;
+		if (bdev_can_atomic_write(btp->bt_bdev))
+			xfs_configure_buftarg_atomic_writes(btp);
 	}
 
-	if (bdev_can_atomic_write(btp->bt_bdev))
-		xfs_configure_buftarg_atomic_writes(btp);
+	btp->bt_meta_sectorsize = sectorsize;
+	btp->bt_meta_sectormask = sectorsize - 1;
+	/* m_blkbb_log is not set up yet */
+	btp->bt_nr_sectors = nr_blocks << (mp->m_sb.sb_blocklog - BBSHIFT);
 	return 0;
 }
 
@@ -1749,6 +1750,9 @@ xfs_init_buftarg(
 	size_t				logical_sectorsize,
 	const char			*descr)
 {
+	/* The maximum size of the buftarg is only known once the sb is read. */
+	btp->bt_nr_sectors = (xfs_daddr_t)-1;
+
 	/* Set up device logical sector size mask */
 	btp->bt_logical_sectorsize = logical_sectorsize;
 	btp->bt_logical_sectormask = logical_sectorsize - 1;