Commit 330c7295 authored May 23, 2019 by Sam Eiderman Committed by Max Reitz May 28, 2019

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>

parent 863cc78f

qemu-img.c

+23 −10

Original line number	Diff line number	Diff line
		@@ -3358,7 +3358,19 @@ static int img_rebase(int argc, char **argv)
		* in its chain.
		*/
		prefix_chain_bs = bdrv_find_backing_image(bs, out_real_path);

		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);
		@@ -3371,6 +3383,7 @@ static int img_rebase(int argc, char **argv)
		}
		}
		}
		}

		/*
		* Check each unallocated cluster in the COW file. If it is unallocated,