[PATCH v2 12/13] xfs: make the calculation generic in xfs_sb_validate_fsb_count()

From: Pankaj Raghav (Samsung)
Date: Fri Mar 01 2024 - 11:54:45 EST


From: Pankaj Raghav <p.raghav@xxxxxxxxxxx>

Instead of assuming that PAGE_SHIFT is always higher than the blocklog,
make the calculation generic so that page cache count can be calculated
correctly for LBS.

Signed-off-by: Pankaj Raghav <p.raghav@xxxxxxxxxxx>
---
fs/xfs/xfs_mount.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index aabb25dc3efa..9cf800586da7 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -133,9 +133,16 @@ xfs_sb_validate_fsb_count(
{
ASSERT(PAGE_SHIFT >= sbp->sb_blocklog);
ASSERT(sbp->sb_blocklog >= BBSHIFT);
+ uint64_t max_index;
+ uint64_t max_bytes;
+
+ if (check_shl_overflow(nblocks, sbp->sb_blocklog, &max_bytes))
+ return -EFBIG;

/* Limited by ULONG_MAX of page cache index */
- if (nblocks >> (PAGE_SHIFT - sbp->sb_blocklog) > ULONG_MAX)
+ max_index = max_bytes >> PAGE_SHIFT;
+
+ if (max_index > ULONG_MAX)
return -EFBIG;
return 0;
}
--
2.43.0