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author | Paolo Bonzini <pbonzini@redhat.com> | 2020-01-08 15:55:55 +0100 |
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committer | Stefan Hajnoczi <stefanha@redhat.com> | 2020-01-30 20:59:41 +0000 |
commit | 18fbd0dec7e05183d7fef636155cd9b3e2ac5013 (patch) | |
tree | 3ef00a36df11e96aa31df46fdcd30cdb720ab7cf /block/io.c | |
parent | c53cb427695214a9cb53e8ace4307c91a6b6e406 (diff) | |
download | qemu-18fbd0dec7e05183d7fef636155cd9b3e2ac5013.zip qemu-18fbd0dec7e05183d7fef636155cd9b3e2ac5013.tar.gz qemu-18fbd0dec7e05183d7fef636155cd9b3e2ac5013.tar.bz2 |
block/io: wait for serialising requests when a request becomes serialising
Marking without waiting would not result in actual serialising behavior.
Thus, make a call bdrv_mark_request_serialising sufficient for
serialisation to happen.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1578495356-46219-3-git-send-email-pbonzini@redhat.com
Message-Id: <1578495356-46219-3-git-send-email-pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'block/io.c')
-rw-r--r-- | block/io.c | 40 |
1 files changed, 17 insertions, 23 deletions
@@ -41,6 +41,7 @@ #define MAX_BOUNCE_BUFFER (32768 << BDRV_SECTOR_BITS) static void bdrv_parent_cb_resize(BlockDriverState *bs); +static bool coroutine_fn bdrv_wait_serialising_requests(BdrvTrackedRequest *self); static int coroutine_fn bdrv_co_do_pwrite_zeroes(BlockDriverState *bs, int64_t offset, int bytes, BdrvRequestFlags flags); @@ -715,7 +716,7 @@ static void tracked_request_begin(BdrvTrackedRequest *req, qemu_co_mutex_unlock(&bs->reqs_lock); } -void bdrv_mark_request_serialising(BdrvTrackedRequest *req, uint64_t align) +bool bdrv_mark_request_serialising(BdrvTrackedRequest *req, uint64_t align) { int64_t overlap_offset = req->offset & ~(align - 1); uint64_t overlap_bytes = ROUND_UP(req->offset + req->bytes, align) @@ -728,18 +729,7 @@ void bdrv_mark_request_serialising(BdrvTrackedRequest *req, uint64_t align) req->overlap_offset = MIN(req->overlap_offset, overlap_offset); req->overlap_bytes = MAX(req->overlap_bytes, overlap_bytes); -} - -static bool is_request_serialising_and_aligned(BdrvTrackedRequest *req) -{ - /* - * If the request is serialising, overlap_offset and overlap_bytes are set, - * so we can check if the request is aligned. Otherwise, don't care and - * return false. - */ - - return req->serialising && (req->offset == req->overlap_offset) && - (req->bytes == req->overlap_bytes); + return bdrv_wait_serialising_requests(req); } /** @@ -823,7 +813,7 @@ void bdrv_dec_in_flight(BlockDriverState *bs) bdrv_wakeup(bs); } -bool coroutine_fn bdrv_wait_serialising_requests(BdrvTrackedRequest *self) +static bool coroutine_fn bdrv_wait_serialising_requests(BdrvTrackedRequest *self) { BlockDriverState *bs = self->bs; BdrvTrackedRequest *req; @@ -1455,10 +1445,10 @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child, * it ensures that the CoR read and write operations are atomic and * guest writes cannot interleave between them. */ bdrv_mark_request_serialising(req, bdrv_get_cluster_size(bs)); + } else { + bdrv_wait_serialising_requests(req); } - bdrv_wait_serialising_requests(req); - if (flags & BDRV_REQ_COPY_ON_READ) { int64_t pnum; @@ -1851,13 +1841,19 @@ bdrv_co_write_req_prepare(BdrvChild *child, int64_t offset, uint64_t bytes, assert(!(flags & ~BDRV_REQ_MASK)); if (flags & BDRV_REQ_SERIALISING) { - bdrv_mark_request_serialising(req, bdrv_get_cluster_size(bs)); + waited = bdrv_mark_request_serialising(req, bdrv_get_cluster_size(bs)); + /* + * For a misaligned request we should have already waited earlier, + * because we come after bdrv_padding_rmw_read which must be called + * with the request already marked as serialising. + */ + assert(!waited || + (req->offset == req->overlap_offset && + req->bytes == req->overlap_bytes)); + } else { + bdrv_wait_serialising_requests(req); } - waited = bdrv_wait_serialising_requests(req); - - assert(!waited || !req->serialising || - is_request_serialising_and_aligned(req)); assert(req->overlap_offset <= offset); assert(offset + bytes <= req->overlap_offset + req->overlap_bytes); assert(end_sector <= bs->total_sectors || child->perm & BLK_PERM_RESIZE); @@ -2019,7 +2015,6 @@ static int coroutine_fn bdrv_co_do_zero_pwritev(BdrvChild *child, padding = bdrv_init_padding(bs, offset, bytes, &pad); if (padding) { bdrv_mark_request_serialising(req, align); - bdrv_wait_serialising_requests(req); bdrv_padding_rmw_read(child, req, &pad, true); @@ -2122,7 +2117,6 @@ int coroutine_fn bdrv_co_pwritev_part(BdrvChild *child, if (bdrv_pad_request(bs, &qiov, &qiov_offset, &offset, &bytes, &pad)) { bdrv_mark_request_serialising(&req, align); - bdrv_wait_serialising_requests(&req); bdrv_padding_rmw_read(child, &req, &pad, false); } |