diff options
| -rw-r--r-- | block/io.c | 9 | ||||
| -rw-r--r-- | block/qcow2.c | 1 | ||||
| -rw-r--r-- | block/qed.c | 1 | ||||
| -rw-r--r-- | include/block/block.h | 5 | ||||
| -rw-r--r-- | include/block/block_int.h | 12 |
5 files changed, 13 insertions, 15 deletions
diff --git a/block/io.c b/block/io.c index 36d4d562a6..b6564e34c5 100644 --- a/block/io.c +++ b/block/io.c @@ -2406,7 +2406,7 @@ static int coroutine_fn bdrv_co_block_status(BlockDriverState *bs, if (ret & (BDRV_BLOCK_DATA | BDRV_BLOCK_ZERO)) { ret |= BDRV_BLOCK_ALLOCATED; - } else if (want_zero) { + } else if (want_zero && bs->drv->supports_backing) { if (bs->backing) { BlockDriverState *bs2 = bs->backing->bs; int64_t size2 = bdrv_getlength(bs2); @@ -2415,12 +2415,7 @@ static int coroutine_fn bdrv_co_block_status(BlockDriverState *bs, ret |= BDRV_BLOCK_ZERO; } } else { - BlockDriverInfo bdi; - int ret2 = bdrv_get_info(bs, &bdi); - - if (ret2 == 0 && bdi.unallocated_blocks_are_zero) { - ret |= BDRV_BLOCK_ZERO; - } + ret |= BDRV_BLOCK_ZERO; } } diff --git a/block/qcow2.c b/block/qcow2.c index 30f073cf2a..38198b4e75 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -4987,7 +4987,6 @@ err: static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) { BDRVQcow2State *s = bs->opaque; - bdi->unallocated_blocks_are_zero = true; bdi->cluster_size = s->cluster_size; bdi->vm_state_offset = qcow2_vm_state_offset(s); return 0; diff --git a/block/qed.c b/block/qed.c index c0c65015c7..a2dd952699 100644 --- a/block/qed.c +++ b/block/qed.c @@ -1514,7 +1514,6 @@ static int bdrv_qed_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) memset(bdi, 0, sizeof(*bdi)); bdi->cluster_size = s->header.cluster_size; bdi->is_dirty = s->header.features & QED_F_NEED_CHECK; - bdi->unallocated_blocks_are_zero = true; return 0; } diff --git a/include/block/block.h b/include/block/block.h index e7934e07f2..bca3bb831c 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -22,11 +22,6 @@ typedef struct BlockDriverInfo { int64_t vm_state_offset; bool is_dirty; /* - * True if unallocated blocks read back as zeroes. This is equivalent - * to the LBPRZ flag in the SCSI logical block provisioning page. - */ - bool unallocated_blocks_are_zero; - /* * True if this block driver only supports compressed writes */ bool needs_compressed_writes; diff --git a/include/block/block_int.h b/include/block/block_int.h index 1b86b59af1..3d6cf88592 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -123,7 +123,17 @@ struct BlockDriver { */ bool bdrv_needs_filename; - /* Set if a driver can support backing files */ + /* + * Set if a driver can support backing files. This also implies the + * following semantics: + * + * - Return status 0 of .bdrv_co_block_status means that corresponding + * blocks are not allocated in this layer of backing-chain + * - For such (unallocated) blocks, read will: + * - fill buffer with zeros if there is no backing file + * - read from the backing file otherwise, where the block layer + * takes care of reading zeros beyond EOF if backing file is short + */ bool supports_backing; /* For handling image reopen for split or non-split files */ |