- assert the alignment on return if the allocation has to stop (at the start of a running allocation) - make use of const specifiers for local variables
Signed-off-by: Anton Nefedov <anton.nefe...@virtuozzo.com> Signed-off-by: Denis V. Lunev <d...@openvz.org> --- block/qcow2-cluster.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index 3dafd19..95e8862 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -900,15 +900,15 @@ out: * Check if there already is an AIO write request in flight which allocates * the same cluster. In this case we need to wait until the previous * request has completed and updated the L2 table accordingly. - * * Returns: * 0 if there was no dependency. *cur_bytes indicates the number of * bytes from guest_offset that can be read before the next - * dependency must be processed (or the request is complete) + * dependency must be processed (or the request is complete). + * *m is not modified * - * -EAGAIN if we had to wait for another request, previously gathered - * information on cluster allocation may be invalid now. The caller - * must start over anyway, so consider *cur_bytes undefined. + * -EAGAIN if we had to wait for another request. The caller + * must start over, so consider *cur_bytes undefined. + * *m is not modified */ static int handle_dependencies(BlockDriverState *bs, uint64_t guest_offset, uint64_t *cur_bytes, QCowL2Meta **m) @@ -919,10 +919,10 @@ static int handle_dependencies(BlockDriverState *bs, uint64_t guest_offset, QLIST_FOREACH(old_alloc, &s->cluster_allocs, next_in_flight) { - uint64_t start = guest_offset; - uint64_t end = start + bytes; - uint64_t old_start = l2meta_cow_start(old_alloc); - uint64_t old_end = l2meta_cow_end(old_alloc); + const uint64_t start = guest_offset; + const uint64_t end = start + bytes; + const uint64_t old_start = l2meta_cow_start(old_alloc); + const uint64_t old_end = l2meta_cow_end(old_alloc); if (end <= old_start || start >= old_end) { /* No intersection */ @@ -939,6 +939,8 @@ static int handle_dependencies(BlockDriverState *bs, uint64_t guest_offset, * and deal with requests depending on them before starting to * gather new ones. Not worth the trouble. */ if (bytes == 0 && *m) { + /* start must be cluster aligned at this point */ + assert(start == start_of_cluster(s, start)); *cur_bytes = 0; return 0; } -- 2.7.4