From d6a03733e6755d4b59f8009239af8f0a3e12c171 Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Tue, 3 Dec 2013 14:02:23 +0100 Subject: [PATCH 13/37] block: Introduce bdrv_aligned_pwritev() Message-id: <1392117622-28812-14-git-send-email-kwolf@redhat.com> Patchwork-id: 57178 O-Subject: [RHEL-7.0 qemu-kvm PATCH v2 13/37] block: Introduce bdrv_aligned_pwritev() Bugzilla: 748906 RH-Acked-by: Laszlo Ersek RH-Acked-by: Stefan Hajnoczi RH-Acked-by: Max Reitz This separates the part of bdrv_co_do_writev() that needs to happen before the request is modified to match the backend alignment, and a part that needs to be executed afterwards and passes the request to the BlockDriver. Signed-off-by: Kevin Wolf Reviewed-by: Max Reitz Reviewed-by: Benoit Canet (cherry picked from commit b404f72036716ab8ace04b83a8f0a93be4739a6a) Conflicts: block.c Conflict because RHEL 7 still has the old I/O throttling code. Signed-off-by: Kevin Wolf --- block.c | 62 +++++++++++++++++++++++++++++++++++++++++--------------------- 1 file changed, 41 insertions(+), 21 deletions(-) --- block.c | 62 +++++++++++++++++++++++++++++++++++++++++--------------------- 1 files changed, 41 insertions(+), 21 deletions(-) diff --git a/block.c b/block.c index ce3edb0..e6b6ed4 100644 --- a/block.c +++ b/block.c @@ -2982,34 +2982,20 @@ static int coroutine_fn bdrv_co_do_write_zeroes(BlockDriverState *bs, } /* - * Handle a write request in coroutine context + * Forwards an already correctly aligned write request to the BlockDriver. */ -static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs, - int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, - BdrvRequestFlags flags) +static int coroutine_fn bdrv_aligned_pwritev(BlockDriverState *bs, + int64_t offset, unsigned int bytes, QEMUIOVector *qiov, int flags) { BlockDriver *drv = bs->drv; BdrvTrackedRequest req; int ret; - if (!bs->drv) { - return -ENOMEDIUM; - } - if (bs->read_only) { - return -EACCES; - } - if (bdrv_check_request(bs, sector_num, nb_sectors)) { - return -EIO; - } - - /* throttling disk write I/O */ - if (bs->io_limits_enabled) { - bdrv_io_limits_intercept(bs, true, nb_sectors); - } + int64_t sector_num = offset >> BDRV_SECTOR_BITS; + unsigned int nb_sectors = bytes >> BDRV_SECTOR_BITS; - if (bs->copy_on_read_in_flight) { - wait_for_overlapping_requests(bs, sector_num, nb_sectors); - } + assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0); + assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0); tracked_request_begin(&req, bs, sector_num, nb_sectors, true); @@ -3039,6 +3025,40 @@ static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs, return ret; } +/* + * Handle a write request in coroutine context + */ +static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs, + int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, + BdrvRequestFlags flags) +{ + int ret; + + if (!bs->drv) { + return -ENOMEDIUM; + } + if (bs->read_only) { + return -EACCES; + } + if (bdrv_check_request(bs, sector_num, nb_sectors)) { + return -EIO; + } + + if (bs->copy_on_read_in_flight) { + wait_for_overlapping_requests(bs, sector_num, nb_sectors); + } + + /* throttling disk I/O */ + if (bs->io_limits_enabled) { + bdrv_io_limits_intercept(bs, true, nb_sectors); + } + + ret = bdrv_aligned_pwritev(bs, sector_num << BDRV_SECTOR_BITS, + nb_sectors << BDRV_SECTOR_BITS, qiov, flags); + + return ret; +} + int coroutine_fn bdrv_co_writev(BlockDriverState *bs, int64_t sector_num, int nb_sectors, QEMUIOVector *qiov) { -- 1.7.1