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