diff options
| -rw-r--r-- | block/vdi.c | 23 |
1 files changed, 14 insertions, 9 deletions
diff --git a/block/vdi.c b/block/vdi.c index 883046d5a2..523a6409c5 100644 --- a/block/vdi.c +++ b/block/vdi.c @@ -114,8 +114,13 @@ void uuid_unparse(const uuid_t uu, char *out); */ #define VDI_TEXT "<<< QEMU VM Virtual Disk Image >>>\n" -/* Unallocated blocks use this index (no need to convert endianness). */ -#define VDI_UNALLOCATED UINT32_MAX +/* A never-allocated block; semantically arbitrary content. */ +#define VDI_UNALLOCATED 0xffffffffU + +/* A discarded (no longer allocated) block; semantically zero-filled. */ +#define VDI_DISCARDED 0xfffffffeU + +#define VDI_IS_ALLOCATED(X) ((X) < VDI_DISCARDED) #if !defined(CONFIG_UUID) void uuid_generate(uuid_t out) @@ -307,10 +312,10 @@ static int vdi_check(BlockDriverState *bs, BdrvCheckResult *res) /* Check block map and value of blocks_allocated. */ for (block = 0; block < s->header.blocks_in_image; block++) { uint32_t bmap_entry = le32_to_cpu(s->bmap[block]); - if (bmap_entry != VDI_UNALLOCATED) { + if (VDI_IS_ALLOCATED(bmap_entry)) { if (bmap_entry < s->header.blocks_in_image) { blocks_allocated++; - if (bmap[bmap_entry] == VDI_UNALLOCATED) { + if (!VDI_IS_ALLOCATED(bmap[bmap_entry])) { bmap[bmap_entry] = bmap_entry; } else { fprintf(stderr, "ERROR: block index %" PRIu32 @@ -472,7 +477,7 @@ static int vdi_is_allocated(BlockDriverState *bs, int64_t sector_num, n_sectors = nb_sectors; } *pnum = n_sectors; - return bmap_entry != VDI_UNALLOCATED; + return VDI_IS_ALLOCATED(bmap_entry); } static void vdi_aio_cancel(BlockDriverAIOCB *blockacb) @@ -603,7 +608,7 @@ static void vdi_aio_read_cb(void *opaque, int ret) /* prepare next AIO request */ acb->n_sectors = n_sectors; bmap_entry = le32_to_cpu(s->bmap[block_index]); - if (bmap_entry == VDI_UNALLOCATED) { + if (!VDI_IS_ALLOCATED(bmap_entry)) { /* Block not allocated, return zeros, no need to wait. */ memset(acb->buf, 0, n_sectors * SECTOR_SIZE); ret = vdi_schedule_bh(vdi_aio_rw_bh, acb); @@ -685,7 +690,7 @@ static void vdi_aio_write_cb(void *opaque, int ret) if (acb->header_modified) { VdiHeader *header = acb->block_buffer; logout("now writing modified header\n"); - assert(acb->bmap_first != VDI_UNALLOCATED); + assert(VDI_IS_ALLOCATED(acb->bmap_first)); *header = s->header; vdi_header_to_le(header); acb->header_modified = 0; @@ -699,7 +704,7 @@ static void vdi_aio_write_cb(void *opaque, int ret) goto done; } return; - } else if (acb->bmap_first != VDI_UNALLOCATED) { + } else if (VDI_IS_ALLOCATED(acb->bmap_first)) { /* One or more new blocks were allocated. */ uint64_t offset; uint32_t bmap_first; @@ -749,7 +754,7 @@ static void vdi_aio_write_cb(void *opaque, int ret) /* prepare next AIO request */ acb->n_sectors = n_sectors; bmap_entry = le32_to_cpu(s->bmap[block_index]); - if (bmap_entry == VDI_UNALLOCATED) { + if (!VDI_IS_ALLOCATED(bmap_entry)) { /* Allocate new block and write to it. */ uint64_t offset; uint8_t *block; |