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authorMax Reitz <mreitz@redhat.com>2015-07-27 17:51:35 +0200
committerKevin Wolf <kwolf@redhat.com>2015-12-18 14:34:43 +0100
commit1038bbb803b1630a5d9b91d185b5957a25d4710d (patch)
treea33b854a9ebd215b8ab93ef06257829de4072ac0 /block/qcow2.c
parent164e0f89cc825bf2a83b20451643db333d2891a7 (diff)
qcow2: Split upgrade/downgrade paths for amend
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>
Diffstat (limited to 'block/qcow2.c')
-rw-r--r--block/qcow2.c31
1 files changed, 16 insertions, 15 deletions
diff --git a/block/qcow2.c b/block/qcow2.c
index 381b4f7ed3..07a4f0bab2 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -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;
}