block: Add blk_new_with_bs() helper

There are several callers that need to create a new block backend from
an existing BDS; make the task slightly easier with a common helper
routine.

Suggested-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200424190903.522087-2-eblake@redhat.com>
[mreitz: Set @ret only in error paths, see
 https://lists.nongnu.org/archive/html/qemu-block/2020-04/msg01216.html]
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200428192648.749066-2-eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
This commit is contained in:
Eric Blake
2020-04-28 14:26:46 -05:00
committed by Max Reitz
parent 52ea799e96
commit a3aeeab557
14 changed files with 75 additions and 59 deletions

View File

@@ -2711,7 +2711,6 @@ void qmp_block_resize(bool has_device, const char *device,
BlockBackend *blk = NULL;
BlockDriverState *bs;
AioContext *aio_context;
int ret;
bs = bdrv_lookup_bs(has_device ? device : NULL,
has_node_name ? node_name : NULL,
@@ -2734,14 +2733,13 @@ void qmp_block_resize(bool has_device, const char *device,
goto out;
}
blk = blk_new(bdrv_get_aio_context(bs), BLK_PERM_RESIZE, BLK_PERM_ALL);
ret = blk_insert_bs(blk, bs, errp);
if (ret < 0) {
blk = blk_new_with_bs(bs, BLK_PERM_RESIZE, BLK_PERM_ALL, errp);
if (!blk) {
goto out;
}
bdrv_drained_begin(bs);
ret = blk_truncate(blk, size, false, PREALLOC_MODE_OFF, 0, errp);
blk_truncate(blk, size, false, PREALLOC_MODE_OFF, 0, errp);
bdrv_drained_end(bs);
out: