From c659199f9bf37c798bd741ddd151db213d5d73f8 Mon Sep 17 00:00:00 2001 From: Jeffrey Cody Date: Tue, 11 Feb 2014 16:14:25 +0100 Subject: [PATCH 19/28] block: resize backing file image during offline commit, if necessary RH-Author: Jeffrey Cody Message-id: <54cb47d8cd589585e9788df80b9612ea527e193d.1392134912.git.jcody@redhat.com> Patchwork-id: 57215 O-Subject: [RHEL7 qemu-kvm PATCH 1/6] block: resize backing file image during offline commit, if necessary Bugzilla: 1047254 RH-Acked-by: Kevin Wolf RH-Acked-by: Markus Armbruster RH-Acked-by: Miroslav Rezanina 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 (cherry picked from commit 72706ea4cd38bfcb151265df0178ba21863d7518) --- block.c | 28 +++++++++++++++++++++++++--- 1 file changed, 25 insertions(+), 3 deletions(-) Signed-off-by: Miroslav Rezanina --- block.c | 28 +++++++++++++++++++++++++--- 1 files changed, 25 insertions(+), 3 deletions(-) diff --git a/block.c b/block.c index 1b57236..c7aa285 100644 --- a/block.c +++ b/block.c @@ -1947,10 +1947,10 @@ 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) @@ -1975,7 +1975,29 @@ 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) { -- 1.7.1