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author | Fam Zheng <famz@redhat.com> | 2015-06-08 13:56:07 +0800 |
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committer | Stefan Hajnoczi <stefanha@redhat.com> | 2015-07-02 10:03:50 +0100 |
commit | ba3f0e2545c365ebe1dbddb0e53058710d41881e (patch) | |
tree | 39315c57080955d17bb4be1ec3053faec12a842c | |
parent | e0cf11f31c24cfb17f44ed46c254d84c78e7f6e9 (diff) | |
download | qemu-ba3f0e2545c365ebe1dbddb0e53058710d41881e.zip qemu-ba3f0e2545c365ebe1dbddb0e53058710d41881e.tar.gz qemu-ba3f0e2545c365ebe1dbddb0e53058710d41881e.tar.bz2 |
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: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
-rw-r--r-- | block/io.c | 56 | ||||
-rw-r--r-- | include/block/block.h | 4 |
2 files changed, 49 insertions, 11 deletions
@@ -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->pnum); + 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, - 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) { 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) { diff --git a/include/block/block.h b/include/block/block.h index 07bb724..06e4137 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -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, |