From: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com>
The comments states, that on misaligned request we should have already
been waiting. But for bdrv_padding_rmw_read, we called
bdrv_mark_request_serialising with align = request_alignment, and now
we serialise with align = cluster_size. So we may have to wait again
with larger alignment.
Note, that the only user of BDRV_REQ_SERIALISING is backup which issues
cluster-aligned requests, so seems the assertion should not fire for
now. But it's wrong anyway.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com>
Reviewed-by: Paolo Bonzini <pbonz...@redhat.com>
Message-Id: <20201021145859.11201-3-vsement...@virtuozzo.com>
Signed-off-by: Max Reitz <mre...@redhat.com>
---
block/io.c | 11 +----------
1 file changed, 1 insertion(+), 10 deletions(-)
diff --git a/block/io.c b/block/io.c
index 24205f5168..27370107b2 100644
--- a/block/io.c
+++ b/block/io.c
@@ -1827,7 +1827,6 @@ bdrv_co_write_req_prepare(BdrvChild *child, int64_t
offset, uint64_t bytes,
BdrvTrackedRequest *req, int flags)
{
BlockDriverState *bs = child->bs;
- bool waited;
int64_t end_sector = DIV_ROUND_UP(offset + bytes, BDRV_SECTOR_SIZE);
if (bs->read_only) {
@@ -1839,15 +1838,7 @@ bdrv_co_write_req_prepare(BdrvChild *child, int64_t
offset, uint64_t bytes,
assert(!(flags & ~BDRV_REQ_MASK));
if (flags & BDRV_REQ_SERIALISING) {
- waited = bdrv_mark_request_serialising(req, bdrv_get_cluster_size(bs));
- /*
- * For a misaligned request we should have already waited earlier,
- * because we come after bdrv_padding_rmw_read which must be called
- * with the request already marked as serialising.
- */
- assert(!waited ||
- (req->offset == req->overlap_offset &&
- req->bytes == req->overlap_bytes));
+ bdrv_mark_request_serialising(req, bdrv_get_cluster_size(bs));
} else {
bdrv_wait_serialising_requests(req);
}
--
2.29.2
