[PATCH AUTOSEL 6.12 18/20] iomap: avoid avoid truncating 64-bit offset to 32 bits

Sasha Levin
2025-01-13T18:35:07Z

From: Marco Nelissen <marco.nelissen@gmail.com>

[ Upstream commit c13094b894de289514d84b8db56d1f2931a0bade ]

on 32-bit kernels, iomap_write_delalloc_scan() was inadvertently using a
32-bit position due to folio_next_index() returning an unsigned long.
This could lead to an infinite loop when writing to an xfs filesystem.

Signed-off-by: Marco Nelissen <marco.nelissen@gmail.com>
Link: https://lore.kernel.org/r/20250109041253.2494374-1-marco.nelissen@gmail.com
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/iomap/buffered-io.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 3ffd9937dd51..49da74539fb3 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -1138,7 +1138,7 @@ static void iomap_write_delalloc_scan(struct inode *inode,
start_byte, end_byte, iomap, punch);

/* move offset to start of next folio in range */
- start_byte = folio_next_index(folio) << PAGE_SHIFT;
+ start_byte = folio_pos(folio) + folio_size(folio);
folio_unlock(folio);
folio_put(folio);
}
--
2.39.5