[PATCH 01/43] xfs: factor out a xfs_rt_check_size helper

Christoph Hellwig
2025-02-06T06:45:16Z

Add a helper to check that the last block of a RT device is readable
to share the code between mount and growfs. This also adds the mount
time overflow check to growfs and improves the error messages.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
---
fs/xfs/xfs_rtalloc.c | 62 ++++++++++++++++++++++----------------------
1 file changed, 31 insertions(+), 31 deletions(-)

diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c
index d8e6d073d64d..bc18b694db75 100644
--- a/fs/xfs/xfs_rtalloc.c
+++ b/fs/xfs/xfs_rtalloc.c
@@ -1248,6 +1248,34 @@ xfs_grow_last_rtg(
mp->m_sb.sb_rgextents;
}

+/*
+ * Read in the last block of the RT device to make sure it is accessible.
+ */
+static int
+xfs_rt_check_size(
+ struct xfs_mount *mp,
+ xfs_rfsblock_t last_block)
+{
+ xfs_daddr_t daddr = XFS_FSB_TO_BB(mp, last_block);
+ struct xfs_buf *bp;
+ int error;
+
+ if (XFS_BB_TO_FSB(mp, daddr) != last_block) {
+ xfs_warn(mp, "RT device size overflow: %llu != %llu",
+ XFS_BB_TO_FSB(mp, daddr), last_block);
+ return -EFBIG;
+ }
+
+ error = xfs_buf_read_uncached(mp->m_rtdev_targp, daddr,
+ XFS_FSB_TO_BB(mp, 1), 0, &bp, NULL);
+ if (error)
+ xfs_warn(mp, "cannot read last RT device sector (%lld)",
+ last_block);
+ else
+ xfs_buf_relse(bp);
+ return error;
+}
+
/*
* Grow the realtime area of the filesystem.
*/
@@ -1259,7 +1287,6 @@ xfs_growfs_rt(
xfs_rgnumber_t old_rgcount = mp->m_sb.sb_rgcount;
xfs_rgnumber_t new_rgcount = 1;
xfs_rgnumber_t rgno;
- struct xfs_buf *bp;
xfs_agblock_t old_rextsize = mp->m_sb.sb_rextsize;
int error;

@@ -1302,15 +1329,10 @@ xfs_growfs_rt(
error = xfs_sb_validate_fsb_count(&mp->m_sb, in->newblocks);
if (error)
goto out_unlock;
- /*
- * Read in the last block of the device, make sure it exists.
- */
- error = xfs_buf_read_uncached(mp->m_rtdev_targp,
- XFS_FSB_TO_BB(mp, in->newblocks - 1),
- XFS_FSB_TO_BB(mp, 1), 0, &bp, NULL);
+
+ error = xfs_rt_check_size(mp, in->newblocks - 1);
if (error)
goto out_unlock;
- xfs_buf_relse(bp);

/*
* Calculate new parameters. These are the final values to be reached.
@@ -1444,10 +1466,6 @@ int /* error */
xfs_rtmount_init(
struct xfs_mount *mp) /* file system mount structure */
{
- struct xfs_buf *bp; /* buffer for last block of subvolume */
- xfs_daddr_t d; /* address of last block of subvolume */
- int error;
-
if (mp->m_sb.sb_rblocks == 0)
return 0;
if (mp->m_rtdev_targp == NULL) {
@@ -1458,25 +1476,7 @@ xfs_rtmount_init(

mp->m_rsumblocks = xfs_rtsummary_blockcount(mp, &mp->m_rsumlevels);

- /*
- * Check that the realtime section is an ok size.
- */
- d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_rblocks);
- if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_rblocks) {
- xfs_warn(mp, "realtime mount -- %llu != %llu",
- (unsigned long long) XFS_BB_TO_FSB(mp, d),
- (unsigned long long) mp->m_sb.sb_rblocks);
- return -EFBIG;
- }
- error = xfs_buf_read_uncached(mp->m_rtdev_targp,
- d - XFS_FSB_TO_BB(mp, 1),
- XFS_FSB_TO_BB(mp, 1), 0, &bp, NULL);
- if (error) {
- xfs_warn(mp, "realtime device size check failed");
- return error;
- }
- xfs_buf_relse(bp);
- return 0;
+ return xfs_rt_check_size(mp, mp->m_sb.sb_rblocks - 1);
}

static int
--
2.45.2