Message ID | 585bd77683536672b18b96b3c3c1b8ad0ff81fa5.1390516414.git.jcody@redhat.com |
---|---|
State | New |
Headers | show |
Am 23.01.2014 um 23:45 hat Jeff Cody geschrieben: > 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> > --- > block.c | 23 ++++++++++++++++++++--- > 1 file changed, 20 insertions(+), 3 deletions(-) > > diff --git a/block.c b/block.c > index 64e7d22..dea7591 100644 > --- a/block.c > +++ b/block.c > @@ -1876,10 +1876,10 @@ 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) > @@ -1904,7 +1904,24 @@ int bdrv_commit(BlockDriverState *bs) > } > } > > - total_sectors = bdrv_getlength(bs) >> BDRV_SECTOR_BITS; > + length = bdrv_getlength(bs); > + backing_length = bdrv_getlength(bs->backing_hd); > + > + if (length < 0 || backing_length < 0) { > + goto ro_cleanup; > + } ret is initialised to 0, so this returns success despite not having committed anything to the backing file. Kevin
diff --git a/block.c b/block.c index 64e7d22..dea7591 100644 --- a/block.c +++ b/block.c @@ -1876,10 +1876,10 @@ 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) @@ -1904,7 +1904,24 @@ int bdrv_commit(BlockDriverState *bs) } } - total_sectors = bdrv_getlength(bs) >> BDRV_SECTOR_BITS; + length = bdrv_getlength(bs); + backing_length = bdrv_getlength(bs->backing_hd); + + if (length < 0 || backing_length < 0) { + 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; buf = g_malloc(COMMIT_BUF_SECTORS * BDRV_SECTOR_SIZE); for (sector = 0; sector < total_sectors; sector += n) {