All new accounts created on Gitlab now require administrator approval. If you invite any collaborators, please let Flux staff know so they can approve the accounts.

Commit 72706ea4 authored by Jeff Cody's avatar Jeff Cody Committed by Kevin Wolf

block: resize backing file image during offline commit, if necessary

Currently, if an image file is logically larger than its backing file,
committing it via 'qemu-img commit' will fail.

For instance, if we have a base image with a virtual size 10G, and a
snapshot image of size 20G, then committing the snapshot offline with
'qemu-img commit' will likely fail.

This will automatically attempt to resize the base image, if the
snapshot image to be committed is larger.
Signed-off-by: default avatarJeff Cody <>
Reviewed-by: default avatarFam Zheng <>
Reviewed-by: default avatarEric Blake <>
Reviewed-by: default avatarBenoit Canet <>
Signed-off-by: default avatarKevin Wolf <>
parent 031fd1be
......@@ -2030,10 +2030,10 @@ int bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix)
int bdrv_commit(BlockDriverState *bs)
BlockDriver *drv = bs->drv;
int64_t sector, total_sectors;
int64_t sector, total_sectors, length, backing_length;
int n, ro, open_flags;
int ret = 0;
uint8_t *buf;
uint8_t *buf = NULL;
char filename[PATH_MAX];
if (!drv)
......@@ -2058,7 +2058,29 @@ int bdrv_commit(BlockDriverState *bs)
total_sectors = bdrv_getlength(bs) >> BDRV_SECTOR_BITS;
length = bdrv_getlength(bs);
if (length < 0) {
ret = length;
goto ro_cleanup;
backing_length = bdrv_getlength(bs->backing_hd);
if (backing_length < 0) {
ret = backing_length;
goto ro_cleanup;
/* If our top snapshot is larger than the backing file image,
* grow the backing file image if possible. If not possible,
* we must return an error */
if (length > backing_length) {
ret = bdrv_truncate(bs->backing_hd, length);
if (ret < 0) {
goto ro_cleanup;
total_sectors = length >> BDRV_SECTOR_BITS;
for (sector = 0; sector < total_sectors; sector += n) {
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment