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qcow2: Split upgrade/downgrade paths for amend

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If the image version should be upgraded, that is the first we should do;
if it should be downgraded, that is the last we should do. So split the
version change block into an upgrade part at the start and a downgrade
part at the end.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Max Reitz 2015-07-27 17:51:35 +02:00 committed by Kevin Wolf
parent 164e0f89cc
commit 1038bbb803
1 changed files with 16 additions and 15 deletions
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31
block/qcow2.c
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@ -3006,20 +3006,13 @@ static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts,
desc++;
}
if (new_version != old_version) {
if (new_version > old_version) {
/* Upgrade */
s->qcow_version = new_version;
ret = qcow2_update_header(bs);
if (ret < 0) {
s->qcow_version = old_version;
return ret;
}
} else {
ret = qcow2_downgrade(bs, new_version, status_cb, cb_opaque);
if (ret < 0) {
return ret;
}
/* Upgrade first (some features may require compat=1.1) */
if (new_version > old_version) {
s->qcow_version = new_version;
ret = qcow2_update_header(bs);
if (ret < 0) {
s->qcow_version = old_version;
return ret;
}
}
@ -3034,7 +3027,7 @@ static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts,
if (s->use_lazy_refcounts != lazy_refcounts) {
if (lazy_refcounts) {
if (s->qcow_version < 3) {
if (new_version < 3) {
error_report("Lazy refcounts only supported with compatibility "
"level 1.1 and above (use compat=1.1 or greater)");
return -EINVAL;
@ -3070,6 +3063,14 @@ static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts,
}
}
/* Downgrade last (so unsupported features can be removed before) */
if (new_version < old_version) {
ret = qcow2_downgrade(bs, new_version, status_cb, cb_opaque);
if (ret < 0) {
return ret;
}
}
return 0;
}