block: resize backing image during active layer commit, if needed
If the top image to commit is the active layer, and also larger than
the base image, then an I/O error will likely be returned during
block-commit.
For instance, if we have a base image with a virtual size 10G, and a
active layer image of size 20G, then committing the snapshot via
'block-commit' will likely fail.
This will automatically attempt to resize the base image, if the
active layer image to be committed is larger.
Signed-off-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block/mirror.c b/block/mirror.c
index 05758e5..2a43334 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -631,11 +631,49 @@
BlockDriverCompletionFunc *cb,
void *opaque, Error **errp)
{
+ int64_t length, base_length;
+ int orig_base_flags;
+
+ orig_base_flags = bdrv_get_flags(base);
+
if (bdrv_reopen(base, bs->open_flags, errp)) {
return;
}
+
+ length = bdrv_getlength(bs);
+ if (length < 0) {
+ error_setg(errp, "Unable to determine length of %s", bs->filename);
+ goto error_restore_flags;
+ }
+
+ base_length = bdrv_getlength(base);
+ if (base_length < 0) {
+ error_setg(errp, "Unable to determine length of %s", base->filename);
+ goto error_restore_flags;
+ }
+
+ if (length > base_length) {
+ if (bdrv_truncate(base, length) < 0) {
+ error_setg(errp, "Top image %s is larger than base image %s, and "
+ "resize of base image failed",
+ bs->filename, base->filename);
+ goto error_restore_flags;
+ }
+ }
+
bdrv_ref(base);
mirror_start_job(bs, base, speed, 0, 0,
on_error, on_error, cb, opaque, errp,
&commit_active_job_driver, false, base);
+ if (error_is_set(errp)) {
+ goto error_restore_flags;
+ }
+
+ return;
+
+error_restore_flags:
+ /* ignore error and errp for bdrv_reopen, because we want to propagate
+ * the original error */
+ bdrv_reopen(base, orig_base_flags, NULL);
+ return;
}
