block: Use blk_make_empty() after commits

bdrv_commit() already has a BlockBackend pointing to the BDS that we
want to empty, it just has the wrong permissions.

qemu-img commit has no BlockBackend pointing to the old backing file
yet, but introducing one is simple.

After this commit, bdrv_make_empty() is the only remaining caller of
BlockDriver.bdrv_make_empty().

Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200429141126.85159-5-mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[kwolf: Fixed up reference output for 098]
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Max Reitz 2020-04-29 16:11:26 +02:00 committed by Kevin Wolf
parent 2b7bbdbdef
commit 2d97fde439
3 changed files with 27 additions and 16 deletions

View file

@ -414,7 +414,9 @@ int bdrv_commit(BlockDriverState *bs)
}
ctx = bdrv_get_aio_context(bs);
src = blk_new(ctx, BLK_PERM_CONSISTENT_READ, BLK_PERM_ALL);
/* WRITE_UNCHANGED is required for bdrv_make_empty() */
src = blk_new(ctx, BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED,
BLK_PERM_ALL);
backing = blk_new(ctx, BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL);
ret = blk_insert_bs(src, bs, &local_err);
@ -492,14 +494,14 @@ int bdrv_commit(BlockDriverState *bs)
}
}
if (drv->bdrv_make_empty) {
ret = drv->bdrv_make_empty(bs);
if (ret < 0) {
goto ro_cleanup;
}
blk_flush(src);
ret = blk_make_empty(src, NULL);
/* Ignore -ENOTSUP */
if (ret < 0 && ret != -ENOTSUP) {
goto ro_cleanup;
}
blk_flush(src);
/*
* Make sure all data we wrote to the backing device is actually
* stable on disk.