From 455a0cc4e93815b2cd2741554076029f2c365e25 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Fri, 18 Oct 2013 08:14:36 +0200 Subject: [PATCH 11/81] block: make bdrv_has_zero_init return false for copy-on-write-images RH-Author: Paolo Bonzini Message-id: <1382084091-16636-12-git-send-email-pbonzini@redhat.com> Patchwork-id: 54994 O-Subject: [RHEL 7.0 qemu-kvm PATCH 11/26] block: make bdrv_has_zero_init return false for copy-on-write-images Bugzilla: 989646 RH-Acked-by: Stefan Hajnoczi RH-Acked-by: Max Reitz RH-Acked-by: Kevin Wolf This helps implementing is_allocated on top of get_block_status. Reviewed-by: Eric Blake Signed-off-by: Paolo Bonzini (cherry picked from commit 11212d8fa08a4e5bd56bb4f6877f9a4c0439a02b) --- block.c | 5 +++++ qemu-img.c | 9 +-------- 2 files changed, 6 insertions(+), 8 deletions(-) Signed-off-by: Miroslav Rezanina --- block.c | 5 +++++ qemu-img.c | 9 +-------- 2 files changed, 6 insertions(+), 8 deletions(-) diff --git a/block.c b/block.c index d838a3c..f5d6658 100644 --- a/block.c +++ b/block.c @@ -2998,6 +2998,11 @@ int bdrv_has_zero_init(BlockDriverState *bs) { assert(bs->drv); + /* If BS is a copy on write image, it is initialized to + the contents of the base image, which may not be zeroes. */ + if (bs->backing_hd) { + return 0; + } if (bs->drv->bdrv_has_zero_init) { return bs->drv->bdrv_has_zero_init(bs); } diff --git a/qemu-img.c b/qemu-img.c index 71cbc59..a9aabd5 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -1511,14 +1511,7 @@ static int img_convert(int argc, char **argv) should add a specific call to have the info to go faster */ buf1 = buf; while (n > 0) { - /* If the output image is being created as a copy on write image, - copy all sectors even the ones containing only NUL bytes, - because they may differ from the sectors in the base image. - - If the output is to a host device, we also write out - sectors that are entirely 0, since whatever data was - already there is garbage, not 0s. */ - if (!has_zero_init || out_baseimg || + if (!has_zero_init || is_allocated_sectors_min(buf1, n, &n1, min_sparse)) { ret = bdrv_write(out_bs, sector_num, buf1, n1); if (ret < 0) { -- 1.7.1