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-rw-r--r--block.c48
-rw-r--r--include/block/block_int.h5
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;