Commit 4caf0fcd authored by Jeff Cody's avatar Jeff Cody Committed by Stefan Hajnoczi
Browse files

block: simplify bdrv_find_base() and bdrv_find_overlay() 



This simplifies the function bdrv_find_overlay().  With this change,
bdrv_find_base() is just a subset of usage of bdrv_find_overlay(),
so this also takes advantage of that.

Reviewed-by: default avatarEric Blake <eblake@redhat.com>
Reviewed-by: default avatarBenoit Canet <benoit@irqsave.net>
Signed-off-by: default avatarJeff Cody <jcody@redhat.com>
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent 7676e2c5

block.c

+10 −35
Original line number Diff line number Diff line
@@ -2508,32 +2508,23 @@ int bdrv_change_backing_file(BlockDriverState *bs, 
 *

 * Returns NULL if bs is not found in active's image chain,

 * or if active == bs.

 *

 * Returns the bottommost base image if bs == NULL.

 */

BlockDriverState *bdrv_find_overlay(BlockDriverState *active,

                                    BlockDriverState *bs)

{

    BlockDriverState *overlay = NULL;

    BlockDriverState *intermediate;



    assert(active != NULL);

    assert(bs != NULL);



    /* if bs is the same as active, then by definition it has no overlay

     */

    if (active == bs) {

        return NULL;

    while (active && bs != active->backing_hd) {

        active = active->backing_hd;

    }



    intermediate = active;

    while (intermediate->backing_hd) {

        if (intermediate->backing_hd == bs) {

            overlay = intermediate;

            break;

        }

        intermediate = intermediate->backing_hd;

    return active;

}



    return overlay;

/* Given a BDS, searches for the base layer. */

BlockDriverState *bdrv_find_base(BlockDriverState *bs)

{

    return bdrv_find_overlay(bs, NULL);

}



typedef struct BlkIntermediateStates {
@@ -4326,22 +4317,6 @@ int bdrv_get_backing_file_depth(BlockDriverState *bs) 
    return 1 + bdrv_get_backing_file_depth(bs->backing_hd);

}



BlockDriverState *bdrv_find_base(BlockDriverState *bs)

{

    BlockDriverState *curr_bs = NULL;



    if (!bs) {

        return NULL;

    }



    curr_bs = bs;



    while (curr_bs->backing_hd) {

        curr_bs = curr_bs->backing_hd;

    }

    return curr_bs;

}



/**************************************************************/

/* async I/Os */