From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53279) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W6kV7-0003q1-Rf for qemu-devel@nongnu.org; Fri, 24 Jan 2014 12:25:10 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1W6kV2-00083E-Pp for qemu-devel@nongnu.org; Fri, 24 Jan 2014 12:25:05 -0500 Received: from mx1.redhat.com ([209.132.183.28]:32953) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W6kV2-000835-Gi for qemu-devel@nongnu.org; Fri, 24 Jan 2014 12:25:00 -0500 From: Kevin Wolf Date: Fri, 24 Jan 2014 18:21:44 +0100 Message-Id: <1390584136-24703-62-git-send-email-kwolf@redhat.com> In-Reply-To: <1390584136-24703-1-git-send-email-kwolf@redhat.com> References: <1390584136-24703-1-git-send-email-kwolf@redhat.com> Subject: [Qemu-devel] [PULL 61/93] block: resize backing file image during offline commit, if necessary List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: anthony@codemonkey.ws Cc: kwolf@redhat.com, qemu-devel@nongnu.org From: Jeff Cody 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 Reviewed-by: Fam Zheng Reviewed-by: Eric Blake Reviewed-by: Benoit Canet Signed-off-by: Kevin Wolf --- block.c | 28 +++++++++++++++++++++++++--- 1 file changed, 25 insertions(+), 3 deletions(-) diff --git a/block.c b/block.c index 18c0a8d..72bccb1 100644 --- a/block.c +++ b/block.c @@ -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; buf = g_malloc(COMMIT_BUF_SECTORS * BDRV_SECTOR_SIZE); for (sector = 0; sector < total_sectors; sector += n) { -- 1.8.1.4