From 65afd211c71fc91750d8a18f9604c1e57a5202fb Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Tue, 3 Dec 2013 14:55:55 +0100 Subject: block: Allow waiting for overlapping requests between begin/end Previously, it was not possible to use wait_for_overlapping_requests() between tracked_request_begin()/end() because it would wait for itself. Ignore the current request in the overlap check and run more of the bdrv_co_do_preadv/pwritev code with a BdrvTrackedRequest present. Signed-off-by: Kevin Wolf Reviewed-by: Max Reitz Reviewed-by: Benoit Canet --- block.c | 38 ++++++++++++++++++++------------------ 1 file changed, 20 insertions(+), 18 deletions(-) (limited to 'block.c') diff --git a/block.c b/block.c index a32c81d644..1591649731 100644 --- a/block.c +++ b/block.c @@ -2286,7 +2286,7 @@ static bool tracked_request_overlaps(BdrvTrackedRequest *req, } static void coroutine_fn wait_for_overlapping_requests(BlockDriverState *bs, - int64_t offset, unsigned int bytes) + BdrvTrackedRequest *self, int64_t offset, unsigned int bytes) { BdrvTrackedRequest *req; int64_t cluster_offset; @@ -2304,6 +2304,9 @@ static void coroutine_fn wait_for_overlapping_requests(BlockDriverState *bs, do { retry = false; QLIST_FOREACH(req, &bs->tracked_requests, list) { + if (req == self) { + continue; + } if (tracked_request_overlaps(req, cluster_offset, cluster_bytes)) { /* Hitting this means there was a reentrant request, for * example, a block driver issuing nested requests. This must @@ -2906,10 +2909,10 @@ err: * implemented by the caller. */ static int coroutine_fn bdrv_aligned_preadv(BlockDriverState *bs, - int64_t offset, unsigned int bytes, QEMUIOVector *qiov, int flags) + BdrvTrackedRequest *req, int64_t offset, unsigned int bytes, + QEMUIOVector *qiov, int flags) { BlockDriver *drv = bs->drv; - BdrvTrackedRequest req; int ret; int64_t sector_num = offset >> BDRV_SECTOR_BITS; @@ -2924,11 +2927,9 @@ static int coroutine_fn bdrv_aligned_preadv(BlockDriverState *bs, } if (bs->copy_on_read_in_flight) { - wait_for_overlapping_requests(bs, offset, bytes); + wait_for_overlapping_requests(bs, req, offset, bytes); } - tracked_request_begin(&req, bs, offset, bytes, false); - if (flags & BDRV_REQ_COPY_ON_READ) { int pnum; @@ -2975,8 +2976,6 @@ static int coroutine_fn bdrv_aligned_preadv(BlockDriverState *bs, } out: - tracked_request_end(&req); - if (flags & BDRV_REQ_COPY_ON_READ) { bs->copy_on_read_in_flight--; } @@ -2992,6 +2991,8 @@ static int coroutine_fn bdrv_co_do_preadv(BlockDriverState *bs, BdrvRequestFlags flags) { BlockDriver *drv = bs->drv; + BdrvTrackedRequest req; + /* TODO Lift BDRV_SECTOR_SIZE restriction in BlockDriver interface */ uint64_t align = MAX(BDRV_SECTOR_SIZE, bs->request_alignment); uint8_t *head_buf = NULL; @@ -3042,9 +3043,11 @@ static int coroutine_fn bdrv_co_do_preadv(BlockDriverState *bs, bytes = ROUND_UP(bytes, align); } - ret = bdrv_aligned_preadv(bs, offset, bytes, + tracked_request_begin(&req, bs, offset, bytes, false); + ret = bdrv_aligned_preadv(bs, &req, offset, bytes, use_local_qiov ? &local_qiov : qiov, flags); + tracked_request_end(&req); if (use_local_qiov) { qemu_iovec_destroy(&local_qiov); @@ -3163,10 +3166,10 @@ static int coroutine_fn bdrv_co_do_write_zeroes(BlockDriverState *bs, * Forwards an already correctly aligned write request to the BlockDriver. */ static int coroutine_fn bdrv_aligned_pwritev(BlockDriverState *bs, - int64_t offset, unsigned int bytes, QEMUIOVector *qiov, int flags) + BdrvTrackedRequest *req, int64_t offset, unsigned int bytes, + QEMUIOVector *qiov, int flags) { BlockDriver *drv = bs->drv; - BdrvTrackedRequest req; int ret; int64_t sector_num = offset >> BDRV_SECTOR_BITS; @@ -3176,12 +3179,10 @@ static int coroutine_fn bdrv_aligned_pwritev(BlockDriverState *bs, assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0); if (bs->copy_on_read_in_flight) { - wait_for_overlapping_requests(bs, offset, bytes); + wait_for_overlapping_requests(bs, req, offset, bytes); } - tracked_request_begin(&req, bs, offset, bytes, true); - - ret = notifier_with_return_list_notify(&bs->before_write_notifiers, &req); + ret = notifier_with_return_list_notify(&bs->before_write_notifiers, req); if (ret < 0) { /* Do nothing, write notifier decided to fail this request */ @@ -3204,8 +3205,6 @@ static int coroutine_fn bdrv_aligned_pwritev(BlockDriverState *bs, bs->total_sectors = MAX(bs->total_sectors, sector_num + nb_sectors); } - tracked_request_end(&req); - return ret; } @@ -3216,6 +3215,7 @@ static int coroutine_fn bdrv_co_do_pwritev(BlockDriverState *bs, int64_t offset, unsigned int bytes, QEMUIOVector *qiov, BdrvRequestFlags flags) { + BdrvTrackedRequest req; int ret; if (!bs->drv) { @@ -3234,7 +3234,9 @@ static int coroutine_fn bdrv_co_do_pwritev(BlockDriverState *bs, bdrv_io_limits_intercept(bs, bytes >> BDRV_SECTOR_BITS, true); } - ret = bdrv_aligned_pwritev(bs, offset, bytes, qiov, flags); + tracked_request_begin(&req, bs, offset, bytes, true); + ret = bdrv_aligned_pwritev(bs, &req, offset, bytes, qiov, flags); + tracked_request_end(&req); return ret; } -- cgit v1.2.1