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[Qemu-devel] [PATCH v2 12/15] qcow2-cluster: slightly refactor handle_de
From: |
Anton Nefedov |
Subject: |
[Qemu-devel] [PATCH v2 12/15] qcow2-cluster: slightly refactor handle_dependencies() |
Date: |
Thu, 1 Jun 2017 18:14:30 +0300 |
- 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 <address@hidden>
Signed-off-by: Denis V. Lunev <address@hidden>
---
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
- Re: [Qemu-devel] [PATCH v2 05/15] qcow2: do not COW the empty areas, (continued)
- [Qemu-devel] [PATCH v2 03/15] blkdebug: support BDRV_REQ_ALLOCATE, Anton Nefedov, 2017/06/01
- [Qemu-devel] [PATCH v2 07/15] qcow2: set inactive flag, Anton Nefedov, 2017/06/01
- [Qemu-devel] [PATCH v2 10/15] qcow2: handle_prealloc(): find out if area zeroed by earlier preallocation, Anton Nefedov, 2017/06/01
- [Qemu-devel] [PATCH v2 06/15] qcow2: preallocation at image expand, Anton Nefedov, 2017/06/01
- [Qemu-devel] [PATCH v2 08/15] qcow2: truncate preallocated space, Anton Nefedov, 2017/06/01
- [Qemu-devel] [PATCH v2 09/15] qcow2: check space leak at the end of the image, Anton Nefedov, 2017/06/01
- [Qemu-devel] [PATCH v2 11/15] qcow2: fix misleading comment about L2 linking, Anton Nefedov, 2017/06/01
- [Qemu-devel] [PATCH v2 12/15] qcow2-cluster: slightly refactor handle_dependencies(),
Anton Nefedov <=
- [Qemu-devel] [PATCH v2 13/15] qcow2-cluster: make handle_dependencies() logic easier to follow, Anton Nefedov, 2017/06/01
- [Qemu-devel] [PATCH v2 15/15] iotest 046: test simultaneous cluster write error case, Anton Nefedov, 2017/06/01
- [Qemu-devel] [PATCH v2 14/15] qcow2: allow concurrent unaligned writes to the same clusters, Anton Nefedov, 2017/06/01
- Re: [Qemu-devel] [PATCH v2 00/15] qcow2: space preallocation and COW improvements, John Snow, 2017/06/01