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[PATCH v3 06/12] block: introduce BDRV_REQ_NO_WAIT flag
From: |
Vladimir Sementsov-Ogievskiy |
Subject: |
[PATCH v3 06/12] block: introduce BDRV_REQ_NO_WAIT flag |
Date: |
Mon, 17 Aug 2020 12:15:47 +0300 |
Add flag to make serialising request no wait: if there are conflicting
requests, just return error immediately. It's will be used in upcoming
preallocate filter.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
include/block/block.h | 9 ++++++++-
block/io.c | 13 ++++++++++++-
2 files changed, 20 insertions(+), 2 deletions(-)
diff --git a/include/block/block.h b/include/block/block.h
index b8f4e86e8d..877fda06a4 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -67,8 +67,15 @@ typedef enum {
* written to qiov parameter which may be NULL.
*/
BDRV_REQ_PREFETCH = 0x200,
+
+ /*
+ * If we need to wait for other requests, just fail immediately. Used
+ * only together with BDRV_REQ_SERIALISING.
+ */
+ BDRV_REQ_NO_WAIT = 0x400,
+
/* Mask of valid flags */
- BDRV_REQ_MASK = 0x3ff,
+ BDRV_REQ_MASK = 0x7ff,
} BdrvRequestFlags;
typedef struct BlockSizes {
diff --git a/block/io.c b/block/io.c
index 96b1b9cf5f..fc6d44d302 100644
--- a/block/io.c
+++ b/block/io.c
@@ -1911,9 +1911,20 @@ bdrv_co_write_req_prepare(BdrvChild *child, int64_t
offset, uint64_t bytes,
assert(!(bs->open_flags & BDRV_O_INACTIVE));
assert((bs->open_flags & BDRV_O_NO_IO) == 0);
assert(!(flags & ~BDRV_REQ_MASK));
+ assert(!((flags & BDRV_REQ_NO_WAIT) && !(flags & BDRV_REQ_SERIALISING)));
if (flags & BDRV_REQ_SERIALISING) {
- bdrv_make_request_serialising(req, bdrv_get_cluster_size(bs));
+ qemu_co_mutex_lock(&bs->reqs_lock);
+
+ tracked_request_set_serialising(req, bdrv_get_cluster_size(bs));
+
+ if ((flags & BDRV_REQ_NO_WAIT) && bdrv_find_conflicting_request(req)) {
+ return -EBUSY;
+ }
+
+ bdrv_wait_serialising_requests_locked(req);
+
+ qemu_co_mutex_unlock(&bs->reqs_lock);
} else {
bdrv_wait_serialising_requests(req);
}
--
2.18.0
- [PATCH v3 00/12] preallocate filter, Vladimir Sementsov-Ogievskiy, 2020/08/17
- [PATCH v3 01/12] block: simplify comment to BDRV_REQ_SERIALISING, Vladimir Sementsov-Ogievskiy, 2020/08/17
- [PATCH v3 02/12] block/io.c: drop assertion on double waiting for request serialisation, Vladimir Sementsov-Ogievskiy, 2020/08/17
- [PATCH v3 03/12] block/io: split out bdrv_find_conflicting_request, Vladimir Sementsov-Ogievskiy, 2020/08/17
- [PATCH v3 05/12] block: bdrv_mark_request_serialising: split non-waiting function, Vladimir Sementsov-Ogievskiy, 2020/08/17
- [PATCH v3 06/12] block: introduce BDRV_REQ_NO_WAIT flag,
Vladimir Sementsov-Ogievskiy <=
- [PATCH v3 04/12] block/io: bdrv_wait_serialising_requests_locked: drop extra bs arg, Vladimir Sementsov-Ogievskiy, 2020/08/17
- [PATCH v3 07/12] block: introduce preallocate filter, Vladimir Sementsov-Ogievskiy, 2020/08/17
- [PATCH v3 09/12] iotests.py: add filter_img_check, Vladimir Sementsov-Ogievskiy, 2020/08/17
- [PATCH v3 10/12] iotests: add 298 to test new preallocate filter driver, Vladimir Sementsov-Ogievskiy, 2020/08/17
- [PATCH v3 11/12] block: add bdrv_is_file_on_fuse helper, Vladimir Sementsov-Ogievskiy, 2020/08/17