diff options
| -rw-r--r-- | block.c | 48 | ||||
| -rw-r--r-- | include/block/block_int.h | 5 |
2 files changed, 32 insertions, 21 deletions
diff --git a/block.c b/block.c index 0a391bd80f..493c75f33e 100644 --- a/block.c +++ b/block.c @@ -2208,6 +2208,10 @@ int bdrv_commit_all(void) */ static void tracked_request_end(BdrvTrackedRequest *req) { + if (req->serialising) { + req->bs->serialising_in_flight--; + } + QLIST_REMOVE(req, list); qemu_co_queue_restart_all(&req->wait_queue); } @@ -2222,10 +2226,11 @@ static void tracked_request_begin(BdrvTrackedRequest *req, { *req = (BdrvTrackedRequest){ .bs = bs, - .offset = offset, - .bytes = bytes, - .is_write = is_write, - .co = qemu_coroutine_self(), + .offset = offset, + .bytes = bytes, + .is_write = is_write, + .co = qemu_coroutine_self(), + .serialising = false, }; qemu_co_queue_init(&req->wait_queue); @@ -2233,6 +2238,14 @@ static void tracked_request_begin(BdrvTrackedRequest *req, QLIST_INSERT_HEAD(&bs->tracked_requests, req, list); } +static void mark_request_serialising(BdrvTrackedRequest *req) +{ + if (!req->serialising) { + req->bs->serialising_in_flight++; + req->serialising = true; + } +} + /** * Round a region to cluster boundaries */ @@ -2285,26 +2298,31 @@ static bool tracked_request_overlaps(BdrvTrackedRequest *req, return true; } -static void coroutine_fn wait_for_overlapping_requests(BlockDriverState *bs, - BdrvTrackedRequest *self, int64_t offset, unsigned int bytes) +static void coroutine_fn wait_serialising_requests(BdrvTrackedRequest *self) { + BlockDriverState *bs = self->bs; BdrvTrackedRequest *req; int64_t cluster_offset; unsigned int cluster_bytes; bool retry; + if (!bs->serialising_in_flight) { + return; + } + /* If we touch the same cluster it counts as an overlap. This guarantees * that allocating writes will be serialized and not race with each other * for the same cluster. For example, in copy-on-read it ensures that the * CoR read and write operations are atomic and guest writes cannot * interleave between them. */ - round_bytes_to_clusters(bs, offset, bytes, &cluster_offset, &cluster_bytes); + round_bytes_to_clusters(bs, self->offset, self->bytes, + &cluster_offset, &cluster_bytes); do { retry = false; QLIST_FOREACH(req, &bs->tracked_requests, list) { - if (req == self) { + if (req == self || (!req->serialising && !self->serialising)) { continue; } if (tracked_request_overlaps(req, cluster_offset, cluster_bytes)) { @@ -2923,12 +2941,10 @@ static int coroutine_fn bdrv_aligned_preadv(BlockDriverState *bs, /* Handle Copy on Read and associated serialisation */ if (flags & BDRV_REQ_COPY_ON_READ) { - bs->copy_on_read_in_flight++; + mark_request_serialising(req); } - if (bs->copy_on_read_in_flight) { - wait_for_overlapping_requests(bs, req, offset, bytes); - } + wait_serialising_requests(req); if (flags & BDRV_REQ_COPY_ON_READ) { int pnum; @@ -2977,10 +2993,6 @@ static int coroutine_fn bdrv_aligned_preadv(BlockDriverState *bs, } out: - if (flags & BDRV_REQ_COPY_ON_READ) { - bs->copy_on_read_in_flight--; - } - return ret; } @@ -3179,9 +3191,7 @@ static int coroutine_fn bdrv_aligned_pwritev(BlockDriverState *bs, assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0); assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0); - if (bs->copy_on_read_in_flight) { - wait_for_overlapping_requests(bs, req, offset, bytes); - } + wait_serialising_requests(req); ret = notifier_with_return_list_notify(&bs->before_write_notifiers, req); diff --git a/include/block/block_int.h b/include/block/block_int.h index bcdd98c503..c1153cb3ab 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -60,6 +60,7 @@ typedef struct BdrvTrackedRequest { int64_t offset; unsigned int bytes; bool is_write; + bool serialising; QLIST_ENTRY(BdrvTrackedRequest) list; Coroutine *co; /* owner, used for deadlock detection */ CoQueue wait_queue; /* coroutines blocked on this request */ @@ -302,8 +303,8 @@ struct BlockDriverState { /* Callback before write request is processed */ NotifierWithReturnList before_write_notifiers; - /* number of in-flight copy-on-read requests */ - unsigned int copy_on_read_in_flight; + /* number of in-flight serialising requests */ + unsigned int serialising_in_flight; /* I/O throttling */ ThrottleState throttle_state; |