From 1ebda71843b6a6ab1431d932f048d2ca8f77dc01 Mon Sep 17 00:00:00 2001 Message-Id: <1ebda71843b6a6ab1431d932f048d2ca8f77dc01.1379425497.git.minovotn@redhat.com> In-Reply-To: References: From: Paolo Bonzini Date: Fri, 6 Sep 2013 18:12:35 +0200 Subject: [PATCH 15/25] qemu-img: always probe the input image for allocated sectors 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 Signed-off-by: Stefan Hajnoczi (cherry picked from commit e4a86f88cc6b214c37b4abe9160e41f0338ce4cd) Signed-off-by: Michal Novotny --- qemu-img.c | 40 +++++++++++++++++++--------------------- 1 file changed, 19 insertions(+), 21 deletions(-) diff --git a/qemu-img.c b/qemu-img.c index bfc2ff3..217246f 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -1126,28 +1126,26 @@ 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; } -- 1.7.11.7