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block: Error out on load_vm with active dirty bitmaps

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Loading a snapshot invalidates the bitmap. Just marking all blocks dirty
is not a useful response in practice, instead the user needs to be aware
that we switch to a completely different state. If they are okay with
losing the dirty bitmap, they can just explicitly delete it.

This effectively reverts commit 04dec3c3ae.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: John Snow <jsnow@redhat.com>
This commit is contained in:
Kevin Wolf 2017-11-20 15:41:31 +01:00
parent 2b624fe079
commit 70a5afedd6
1 changed files with 3 additions and 12 deletions
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15
block/snapshot.c
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@ -182,25 +182,16 @@ int bdrv_snapshot_goto(BlockDriverState *bs,
{
BlockDriver *drv = bs->drv;
int ret, open_ret;
int64_t len;
if (!drv) {
error_setg(errp, "Block driver is closed");
return -ENOMEDIUM;
}
len = bdrv_getlength(bs);
if (len < 0) {
error_setg_errno(errp, -len, "Cannot get block device size");
return len;
if (!QLIST_EMPTY(&bs->dirty_bitmaps)) {
error_setg(errp, "Device has active dirty bitmaps");
return -EBUSY;
}
/* We should set all bits in all enabled dirty bitmaps, because dirty
* bitmaps reflect active state of disk and snapshot switch operation
* actually dirties active state.
* TODO: It may make sense not to set all bits but analyze block status of
* current state and destination snapshot and do not set bits corresponding
* to both-zero or both-unallocated areas. */
bdrv_set_dirty(bs, 0, len);
if (drv->bdrv_snapshot_goto) {
ret = drv->bdrv_snapshot_goto(bs, snapshot_id);