From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49162) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Ys8gE-00048R-4l for qemu-devel@nongnu.org; Tue, 12 May 2015 07:48:58 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Ys8gC-0006Es-5j for qemu-devel@nongnu.org; Tue, 12 May 2015 07:48:58 -0400 From: Fam Zheng Date: Tue, 12 May 2015 19:48:31 +0800 Message-Id: <1431431315-32079-3-git-send-email-famz@redhat.com> In-Reply-To: <1431431315-32079-1-git-send-email-famz@redhat.com> References: <1431431315-32079-1-git-send-email-famz@redhat.com> Subject: [Qemu-devel] [PATCH v3 2/6] block: Fix dirty bitmap in bdrv_co_discard List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Kevin Wolf , qemu-block@nongnu.org, Jeff Cody , Stefan Hajnoczi , pbonzini@redhat.com, jsnow@redhat.com, wangxiaolong@ucloud.cn Unsetting dirty globally with discard is not very correct. The discard may zero out sectors (depending on can_write_zeroes_with_unmap), we should replicate this change to destinition side to make sure that the guest sees the same data. Calling bdrv_reset_dirty also troubles mirror job because the hbitmap iterator doesn't expect unsetting of bits after current position. So let's do it the opposite way which fixes both problems: set the dirty bits if we are to discard it. Reported-by: wangxiaolong@ucloud.cn Signed-off-by: Fam Zheng --- block/io.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/block/io.c b/block/io.c index 1ce62c4..809688b 100644 --- a/block/io.c +++ b/block/io.c @@ -2343,8 +2343,6 @@ int coroutine_fn bdrv_co_discard(BlockDriverState *bs, int64_t sector_num, return -EROFS; } - bdrv_reset_dirty(bs, sector_num, nb_sectors); - /* Do nothing if disabled. */ if (!(bs->open_flags & BDRV_O_UNMAP)) { return 0; @@ -2354,6 +2352,8 @@ int coroutine_fn bdrv_co_discard(BlockDriverState *bs, int64_t sector_num, return 0; } + bdrv_set_dirty(bs, sector_num, nb_sectors); + max_discard = MIN_NON_ZERO(bs->bl.max_discard, BDRV_REQUEST_MAX_SECTORS); while (nb_sectors > 0) { int ret; -- 2.4.0