From 76196ca1133605fa60365b6d00eff5b97fa758ea Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Fri, 18 Oct 2013 08:14:35 +0200 Subject: [PATCH 10/81] qemu-img: always probe the input image for allocated sectors RH-Author: Paolo Bonzini Message-id: <1382084091-16636-11-git-send-email-pbonzini@redhat.com> Patchwork-id: 54993 O-Subject: [RHEL 7.0 qemu-kvm PATCH 10/26] qemu-img: always probe the input image for allocated sectors Bugzilla: 989646 RH-Acked-by: Stefan Hajnoczi RH-Acked-by: Max Reitz RH-Acked-by: Kevin Wolf qemu-img convert can assume "that sectors which are unallocated in the input image are present in both the output's and input's base images". However it is only doing this if the output image returns true for bdrv_has_zero_init(). Testing bdrv_has_zero_init() does not make much sense if the output image is copy-on-write, because a copy-on-write image is never initialized to zero (it is initialized to the content of the backing file). There is nothing here that makes has_zero_init images special. The input and output must be equal for the operation to make sense, and that's it. Reviewed-by: Eric Blake Signed-off-by: Paolo Bonzini (cherry picked from commit e4a86f88cc6b214c37b4abe9160e41f0338ce4cd) --- qemu-img.c | 40 +++++++++++++++++++--------------------- 1 file changed, 19 insertions(+), 21 deletions(-) Signed-off-by: Miroslav Rezanina --- qemu-img.c | 40 +++++++++++++++++++--------------------- 1 files changed, 19 insertions(+), 21 deletions(-) diff --git a/qemu-img.c b/qemu-img.c index 28efb4f..71cbc59 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -1476,28 +1476,26 @@ static int img_convert(int argc, char **argv) n = bs_offset + bs_sectors - sector_num; } - if (has_zero_init) { - /* If the output image is being created as a copy on write image, - assume that sectors which are unallocated in the input image - are present in both the output's and input's base images (no - need to copy them). */ - if (out_baseimg) { - ret = bdrv_is_allocated(bs[bs_i], sector_num - bs_offset, - n, &n1); - if (ret < 0) { - error_report("error while reading metadata for sector " - "%" PRId64 ": %s", - sector_num - bs_offset, strerror(-ret)); - goto out; - } - if (!ret) { - sector_num += n1; - continue; - } - /* The next 'n1' sectors are allocated in the input image. Copy - only those as they may be followed by unallocated sectors. */ - n = n1; + /* If the output image is being created as a copy on write image, + assume that sectors which are unallocated in the input image + are present in both the output's and input's base images (no + need to copy them). */ + if (out_baseimg) { + ret = bdrv_is_allocated(bs[bs_i], sector_num - bs_offset, + n, &n1); + if (ret < 0) { + error_report("error while reading metadata for sector " + "%" PRId64 ": %s", + sector_num - bs_offset, strerror(-ret)); + goto out; + } + if (!ret) { + sector_num += n1; + continue; } + /* The next 'n1' sectors are allocated in the input image. Copy + only those as they may be followed by unallocated sectors. */ + n = n1; } else { n1 = n; } -- 1.7.1