[RESEND PATCH] dm-ebs: Mark full buffer dirty even on partial write

Uladzislau Rezki (Sony)
2025-10-14T14:47:35Z

When performing a read-modify-write(RMW) operation, any modification
to a buffered block must cause the entire buffer to be marked dirty.

Marking only a subrange as dirty is incorrect because the underlying
device block size(ubs) defines the minimum read/write granularity. A
lower device can perform I/O only on regions which are fully aligned
and sized to ubs.

This change ensures that write-back operations always occur in full
ubs-sized chunks, matching the intended emulation semantics of the
EBS target.

Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
---
drivers/md/dm-ebs-target.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/md/dm-ebs-target.c b/drivers/md/dm-ebs-target.c
index 6abb31ca9662..b354e74a670e 100644
--- a/drivers/md/dm-ebs-target.c
+++ b/drivers/md/dm-ebs-target.c
@@ -103,7 +103,7 @@ static int __ebs_rw_bvec(struct ebs_c *ec, enum req_op op, struct bio_vec *bv,
} else {
flush_dcache_page(bv->bv_page);
memcpy(ba, pa, cur_len);
- dm_bufio_mark_partial_buffer_dirty(b, buf_off, buf_off + cur_len);
+ dm_bufio_mark_buffer_dirty(b);
}

dm_bufio_release(b);
--
2.47.3