Commit ba3f0e25 authored by Fam Zheng's avatar Fam Zheng Committed by Stefan Hajnoczi
Browse files

block: Add bdrv_get_block_status_above 



Like bdrv_is_allocated_above, this function follows the backing chain until seeing
BDRV_BLOCK_ALLOCATED.  Base is not included.

Reimplement bdrv_is_allocated on top.

[Initialized bdrv_co_get_block_status_above() ret to 0 to silence
mingw64 compiler warning about the unitialized variable.  assert(bs !=
base) prevents that case but I suppose the program could be compiled
with -DNDEBUG.
--Stefan]

Signed-off-by: default avatarFam Zheng <famz@redhat.com>
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent e0cf11f3

block/io.c

+45 −11
Original line number Diff line number Diff line
@@ -1531,28 +1531,54 @@ static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs, 
    return ret;

}



/* Coroutine wrapper for bdrv_get_block_status() */

static void coroutine_fn bdrv_get_block_status_co_entry(void *opaque)

static int64_t coroutine_fn bdrv_co_get_block_status_above(BlockDriverState *bs,

        BlockDriverState *base,

        int64_t sector_num,

        int nb_sectors,

        int *pnum)

{

    BlockDriverState *p;

    int64_t ret = 0;



    assert(bs != base);

    for (p = bs; p != base; p = p->backing_hd) {

        ret = bdrv_co_get_block_status(p, sector_num, nb_sectors, pnum);

        if (ret < 0 || ret & BDRV_BLOCK_ALLOCATED) {

            break;

        }

        /* [sector_num, pnum] unallocated on this layer, which could be only

         * the first part of [sector_num, nb_sectors].  */

        nb_sectors = MIN(nb_sectors, *pnum);

    }

    return ret;

}



/* Coroutine wrapper for bdrv_get_block_status_above() */

static void coroutine_fn bdrv_get_block_status_above_co_entry(void *opaque)

{

    BdrvCoGetBlockStatusData *data = opaque;

    BlockDriverState *bs = data->bs;



    data->ret = bdrv_co_get_block_status(bs, data->sector_num, data->nb_sectors,

    data->ret = bdrv_co_get_block_status_above(data->bs, data->base,

                                               data->sector_num,

                                               data->nb_sectors,

                                               data->pnum);

    data->done = true;

}



/*

 * Synchronous wrapper around bdrv_co_get_block_status().

 * Synchronous wrapper around bdrv_co_get_block_status_above().

 *

 * See bdrv_co_get_block_status() for details.

 * See bdrv_co_get_block_status_above() for details.

 */

int64_t bdrv_get_block_status(BlockDriverState *bs, int64_t sector_num,

int64_t bdrv_get_block_status_above(BlockDriverState *bs,

                                    BlockDriverState *base,

                                    int64_t sector_num,

                                    int nb_sectors, int *pnum)

{

    Coroutine *co;

    BdrvCoGetBlockStatusData data = {

        .bs = bs,

        .base = base,

        .sector_num = sector_num,

        .nb_sectors = nb_sectors,

        .pnum = pnum,
@@ -1561,11 +1587,11 @@ int64_t bdrv_get_block_status(BlockDriverState *bs, int64_t sector_num, 


    if (qemu_in_coroutine()) {

        /* Fast-path if already in coroutine context */

        bdrv_get_block_status_co_entry(&data);

        bdrv_get_block_status_above_co_entry(&data);

    } else {

        AioContext *aio_context = bdrv_get_aio_context(bs);



        co = qemu_coroutine_create(bdrv_get_block_status_co_entry);

        co = qemu_coroutine_create(bdrv_get_block_status_above_co_entry);

        qemu_coroutine_enter(co, &data);

        while (!data.done) {

            aio_poll(aio_context, true);
@@ -1574,6 +1600,14 @@ int64_t bdrv_get_block_status(BlockDriverState *bs, int64_t sector_num, 
    return data.ret;

}



int64_t bdrv_get_block_status(BlockDriverState *bs,

                              int64_t sector_num,

                              int nb_sectors, int *pnum)

{

    return bdrv_get_block_status_above(bs, bs->backing_hd,

                                       sector_num, nb_sectors, pnum);

}



int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num,

                                   int nb_sectors, int *pnum)

{

include/block/block.h

+4 −0
Original line number Diff line number Diff line
@@ -372,6 +372,10 @@ bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs); 
bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs);

int64_t bdrv_get_block_status(BlockDriverState *bs, int64_t sector_num,

                              int nb_sectors, int *pnum);

int64_t bdrv_get_block_status_above(BlockDriverState *bs,

                                    BlockDriverState *base,

                                    int64_t sector_num,

                                    int nb_sectors, int *pnum);

int bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num, int nb_sectors,

                      int *pnum);

int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base,