Commit 3e8c2e57 authored by Alberto Garcia's avatar Alberto Garcia Committed by Kevin Wolf
Browse files

block: support passing 'backing': '' to 'blockdev-add' 



Passing an empty string allows opening an image but not its backing
file. This was already described in the API documentation, only the
implementation was missing.

This is useful for creating snapshots using images opened with
blockdev-add, since they are not supposed to have a backing image
before the operation.

Signed-off-by: default avatarAlberto Garcia <berto@igalia.com>
Reviewed-by: default avatarMax Reitz <mreitz@redhat.com>
Reviewed-by: default avatarEric Blake <eblake@redhat.com>
Reviewed-by: default avatarKevin Wolf <kwolf@redhat.com>
Reviewed-by: default avatarJeff Cody <jcody@redhat.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent a911e6ae

block.c

+7 −0
Original line number Diff line number Diff line
@@ -1393,6 +1393,7 @@ static int bdrv_open_inherit(BlockDriverState **pbs, const char *filename, 
    BlockDriverState *bs;

    BlockDriver *drv = NULL;

    const char *drvname;

    const char *backing;

    Error *local_err = NULL;

    int snapshot_flags = 0;
@@ -1460,6 +1461,12 @@ static int bdrv_open_inherit(BlockDriverState **pbs, const char *filename, 


    assert(drvname || !(flags & BDRV_O_PROTOCOL));



    backing = qdict_get_try_str(options, "backing");

    if (backing && *backing == '\0') {

        flags |= BDRV_O_NO_BACKING;

        qdict_del(options, "backing");

    }



    bs->open_flags = flags;

    bs->options = options;

    options = qdict_clone_shallow(options);