From 971e56af33f89b4e11a2e6b07b389d729756b9ed Mon Sep 17 00:00:00 2001 From: Kevin Wolf <kwolf@redhat.com> Date: Tue, 3 Dec 2013 14:55:55 +0100 Subject: [PATCH 17/37] block: Allow waiting for overlapping requests between begin/end Message-id: <1392117622-28812-18-git-send-email-kwolf@redhat.com> Patchwork-id: 57182 O-Subject: [RHEL-7.0 qemu-kvm PATCH v2 17/37] block: Allow waiting for overlapping requests between begin/end Bugzilla: 748906 RH-Acked-by: Laszlo Ersek <lersek@redhat.com> RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com> RH-Acked-by: Max Reitz <mreitz@redhat.com> 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 <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net> (cherry picked from commit 65afd211c71fc91750d8a18f9604c1e57a5202fb) Conflicts: block.c Conflicts because in RHEL 7 write notifiers don't exist. Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 36 +++++++++++++++++++----------------- 1 file changed, 19 insertions(+), 17 deletions(-) --- block.c | 36 +++++++++++++++++++----------------- 1 files changed, 19 insertions(+), 17 deletions(-) diff --git a/block.c b/block.c index 09bb127..645bcd0 100644 --- a/block.c +++ b/block.c @@ -2129,7 +2129,7 @@ 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; @@ -2147,6 +2147,9 @@ 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 @@ -2744,10 +2747,10 @@ 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; @@ -2762,11 +2765,9 @@ 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; @@ -2813,8 +2814,6 @@ 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--; } @@ -2830,6 +2829,8 @@ 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; @@ -2880,9 +2881,11 @@ 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); @@ -3001,10 +3004,10 @@ 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; @@ -3014,11 +3017,9 @@ 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); - if (flags & BDRV_REQ_ZERO_WRITE) { ret = bdrv_co_do_write_zeroes(bs, sector_num, nb_sectors, flags); } else { @@ -3040,8 +3041,6 @@ 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; } @@ -3052,6 +3051,7 @@ 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) { @@ -3070,7 +3070,9 @@ static int coroutine_fn bdrv_co_do_pwritev(BlockDriverState *bs, bdrv_io_limits_intercept(bs, true, bytes >> BDRV_SECTOR_BITS); } - 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; } -- 1.7.1