| Message ID | 1431431315-32079-3-git-send-email-famz@redhat.com |
|---|---|
| State | New |
| Headers | show |
On 12/05/2015 13:48, Fam Zheng wrote: > 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 <famz@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> > --- > 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; >
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;
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 <famz@redhat.com> --- block/io.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)