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[PULL 10/30] block: introduce BDRV_REQ_NO_WAIT flag
From: |
Max Reitz |
Subject: |
[PULL 10/30] block: introduce BDRV_REQ_NO_WAIT flag |
Date: |
Fri, 18 Dec 2020 16:12:29 +0100 |
From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
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>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20201021145859.11201-7-vsementsov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
include/block/block.h | 9 ++++++++-
block/io.c | 11 ++++++++++-
2 files changed, 18 insertions(+), 2 deletions(-)
diff --git a/include/block/block.h b/include/block/block.h
index a3f3dcc88f..a193545b6a 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -77,8 +77,15 @@ 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 fadfed3ab8..95b1c56c06 100644
--- a/block/io.c
+++ b/block/io.c
@@ -1858,9 +1858,18 @@ 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_LOCK_GUARD(&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);
} else {
bdrv_wait_serialising_requests(req);
}
--
2.29.2
- [PULL 00/30] Block patches, Max Reitz, 2020/12/18
- [PULL 02/30] block: bdrv_set_perm() drop redundant parameters., Max Reitz, 2020/12/18
- [PULL 01/30] block: add bdrv_refresh_perms() helper, Max Reitz, 2020/12/18
- [PULL 03/30] block: bdrv_child_set_perm() drop redundant parameters., Max Reitz, 2020/12/18
- [PULL 04/30] block: drop tighten_restrictions, Max Reitz, 2020/12/18
- [PULL 07/30] block/io: split out bdrv_find_conflicting_request, Max Reitz, 2020/12/18
- [PULL 06/30] block/io.c: drop assertion on double waiting for request serialisation, Max Reitz, 2020/12/18
- [PULL 09/30] block: bdrv_mark_request_serialising: split non-waiting function, Max Reitz, 2020/12/18
- [PULL 08/30] block/io: bdrv_wait_serialising_requests_locked: drop extra bs arg, Max Reitz, 2020/12/18
- [PULL 05/30] block: simplify comment to BDRV_REQ_SERIALISING, Max Reitz, 2020/12/18
- [PULL 10/30] block: introduce BDRV_REQ_NO_WAIT flag,
Max Reitz <=
- [PULL 11/30] block: bdrv_check_perm(): process children anyway, Max Reitz, 2020/12/18
- [PULL 13/30] qemu-io: add preallocate mode parameter for truncate command, Max Reitz, 2020/12/18
- [PULL 14/30] iotests: qemu_io_silent: support --image-opts, Max Reitz, 2020/12/18
- [PULL 12/30] block: introduce preallocate filter, Max Reitz, 2020/12/18
- [PULL 17/30] scripts/simplebench: fix grammar: s/successed/succeeded/, Max Reitz, 2020/12/18
- [PULL 19/30] scripts/simplebench: use standard deviation for +- error, Max Reitz, 2020/12/18
- [PULL 18/30] scripts/simplebench: support iops, Max Reitz, 2020/12/18
- [PULL 20/30] simplebench: rename ascii() to results_to_text(), Max Reitz, 2020/12/18
- [PULL 22/30] simplebench/results_to_text: improve view of the table, Max Reitz, 2020/12/18
- [PULL 24/30] simplebench/results_to_text: make executable, Max Reitz, 2020/12/18