From d74fe175d34c1b8ef69a8b11a585ffa87fbd69b0 Mon Sep 17 00:00:00 2001 From: Fam Zheng Date: Mon, 13 Jul 2015 03:27:22 +0200 Subject: [PATCH 04/58] block: Fix dirty bitmap in bdrv_co_discard Message-id: <1436758047-4639-5-git-send-email-famz@redhat.com> Patchwork-id: 66962 O-Subject: [RHEL-7.2 qemu-kvm-rhev PATCH 4/9] block: Fix dirty bitmap in bdrv_co_discard Bugzilla: 1242316 RH-Acked-by: Jeffrey Cody RH-Acked-by: Stefan Hajnoczi RH-Acked-by: Paolo Bonzini 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 destination 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 Reviewed-by: Paolo Bonzini Reviewed-by: Eric Blake Signed-off-by: Stefan Hajnoczi (cherry picked from commit 508249952c0ea7472c62e17bf8132295dab4912d) Signed-off-by: Fam Zheng Signed-off-by: Miroslav Rezanina --- block.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/block.c b/block.c index 0b92ecb..84aab22 100644 --- a/block.c +++ b/block.c @@ -5351,8 +5351,6 @@ 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; @@ -5362,6 +5360,8 @@ 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; -- 1.8.3.1