qemu-img: rebase: Reuse in-chain BlockDriverState

If a chain was detected, don't open a new BlockBackend from the target
backing file which will create a new BlockDriverState. Instead, create
an empty BlockBackend and attach the already open BlockDriverState.

Permissions for blk_new() were copied from blk_new_open() when
flags = 0.

Reviewed-by: Karl Heubaum <karl.heubaum@oracle.com>
Reviewed-by: Eyal Moscovici <eyal.moscovici@oracle.com>
Signed-off-by: Sagi Amit <sagi.amit@oracle.com>
Co-developed-by: Sagi Amit <sagi.amit@oracle.com>
Signed-off-by: Sam Eiderman <shmuel.eiderman@oracle.com>
Message-id: 20190523163337.4497-4-shmuel.eiderman@oracle.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
This commit is contained in:
Sam Eiderman 2019-05-23 19:33:37 +03:00 committed by Max Reitz
parent 863cc78f1b
commit 330c729571

View file

@ -3358,16 +3358,29 @@ static int img_rebase(int argc, char **argv)
* in its chain.
*/
prefix_chain_bs = bdrv_find_backing_image(bs, out_real_path);
blk_new_backing = blk_new_open(out_real_path, NULL,
options, src_flags, &local_err);
g_free(out_real_path);
if (!blk_new_backing) {
error_reportf_err(local_err,
"Could not open new backing file '%s': ",
out_baseimg);
ret = -1;
goto out;
if (prefix_chain_bs) {
g_free(out_real_path);
blk_new_backing = blk_new(BLK_PERM_CONSISTENT_READ,
BLK_PERM_ALL);
ret = blk_insert_bs(blk_new_backing, prefix_chain_bs,
&local_err);
if (ret < 0) {
error_reportf_err(local_err,
"Could not reuse backing file '%s': ",
out_baseimg);
goto out;
}
} else {
blk_new_backing = blk_new_open(out_real_path, NULL,
options, src_flags, &local_err);
g_free(out_real_path);
if (!blk_new_backing) {
error_reportf_err(local_err,
"Could not open new backing file '%s': ",
out_baseimg);
ret = -1;
goto out;
}
}
}
}