Commit 5a6684d2 authored by Jeff Cody's avatar Jeff Cody Committed by Stefan Hajnoczi
Browse files

block: add helper function to determine if a BDS is in a chain 



This is a small helper function, to determine if 'base' is in the
chain of BlockDriverState 'top'.  It returns true if it is in the chain,
and false otherwise.

If either argument is NULL, it will also return false.

Reviewed-by: default avatarBenoit Canet <benoit@irqsave.net>
Reviewed-by: default avatarEric Blake <eblake@redhat.com>
Signed-off-by: default avatarJeff Cody <jcody@redhat.com>
Reviewed-by: default avatarKevin Wolf <kwolf@redhat.com>
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent fa40e656

block.c

+11 −0
Original line number Diff line number Diff line
@@ -3774,6 +3774,17 @@ BlockDriverState *bdrv_lookup_bs(const char *device, 
    return NULL;

}



/* If 'base' is in the same chain as 'top', return true. Otherwise,

 * return false.  If either argument is NULL, return false. */

bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base)

{

    while (top && top != base) {

        top = top->backing_hd;

    }



    return top != NULL;

}



BlockDriverState *bdrv_next(BlockDriverState *bs)

{

    if (!bs) {

include/block/block.h

+1 −0
Original line number Diff line number Diff line
@@ -403,6 +403,7 @@ BlockDeviceInfoList *bdrv_named_nodes_list(void); 
BlockDriverState *bdrv_lookup_bs(const char *device,

                                 const char *node_name,

                                 Error **errp);

bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base);

BlockDriverState *bdrv_next(BlockDriverState *bs);

void bdrv_iterate(void (*it)(void *opaque, BlockDriverState *bs),

                  void *opaque);