mirror of https://github.com/proxmox/mirror_qemu
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: Jeff Cody <jcody@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net> Signed-off-by: Kevin Wolf <kwolf@redhat.com>master
parent
031fd1be56
commit
72706ea4cd
28
block.c
28
block.c
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@ -2030,10 +2030,10 @@ int bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix)
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int bdrv_commit(BlockDriverState *bs)
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int bdrv_commit(BlockDriverState *bs)
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{
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{
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BlockDriver *drv = bs->drv;
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BlockDriver *drv = bs->drv;
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int64_t sector, total_sectors;
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int64_t sector, total_sectors, length, backing_length;
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int n, ro, open_flags;
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int n, ro, open_flags;
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int ret = 0;
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int ret = 0;
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uint8_t *buf;
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uint8_t *buf = NULL;
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char filename[PATH_MAX];
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char filename[PATH_MAX];
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if (!drv)
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if (!drv)
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@ -2058,7 +2058,29 @@ int bdrv_commit(BlockDriverState *bs)
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}
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}
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}
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}
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total_sectors = bdrv_getlength(bs) >> BDRV_SECTOR_BITS;
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length = bdrv_getlength(bs);
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if (length < 0) {
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ret = length;
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goto ro_cleanup;
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}
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backing_length = bdrv_getlength(bs->backing_hd);
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if (backing_length < 0) {
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ret = backing_length;
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goto ro_cleanup;
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}
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/* If our top snapshot is larger than the backing file image,
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* grow the backing file image if possible. If not possible,
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* we must return an error */
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if (length > backing_length) {
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ret = bdrv_truncate(bs->backing_hd, length);
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if (ret < 0) {
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goto ro_cleanup;
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}
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}
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total_sectors = length >> BDRV_SECTOR_BITS;
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buf = g_malloc(COMMIT_BUF_SECTORS * BDRV_SECTOR_SIZE);
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buf = g_malloc(COMMIT_BUF_SECTORS * BDRV_SECTOR_SIZE);
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for (sector = 0; sector < total_sectors; sector += n) {
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for (sector = 0; sector < total_sectors; sector += n) {
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