From: Kevin Wolf <kw...@redhat.com>
This implements bdrv_co_get_block_status() for VHD images. This can
significantly speed up qemu-img convert operation because only with this
function implemented sparseness can be considered. (Before, converting a
1 TB empty image took several minutes for me, now it's instantaneous.)
Signed-off-by: Kevin Wolf <kw...@redhat.com>
Reviewed-by: Max Reitz <mre...@redhat.com>
---
block/vpc.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 48 insertions(+), 2 deletions(-)
diff --git a/block/vpc.c b/block/vpc.c
index 7fddbf0..1533b6a 100644
--- a/block/vpc.c
+++ b/block/vpc.c
@@ -597,6 +597,51 @@ static coroutine_fn int vpc_co_write(BlockDriverState *bs,
int64_t sector_num,
return ret;
}
+static int64_t coroutine_fn vpc_co_get_block_status(BlockDriverState *bs,
+ int64_t sector_num, int nb_sectors, int *pnum)
+{
+ BDRVVPCState *s = bs->opaque;
+ VHDFooter *footer = (VHDFooter*) s->footer_buf;
+ int64_t start, offset, next;
+ bool allocated;
+ int n;
+
+ if (be32_to_cpu(footer->type) == VHD_FIXED) {
+ *pnum = nb_sectors;
+ return BDRV_BLOCK_RAW | BDRV_BLOCK_OFFSET_VALID | BDRV_BLOCK_DATA |
+ (sector_num << BDRV_SECTOR_BITS);
+ }
+
+ offset = get_sector_offset(bs, sector_num, 0);
+ start = offset;
+ allocated = (offset != -1);
+ *pnum = 0;
+
+ do {
+ /* All sectors in a block are contiguous (without using the bitmap) */
+ n = ROUND_UP(sector_num + 1, s->block_size / BDRV_SECTOR_SIZE)
+ - sector_num;
+ n = MIN(n, nb_sectors);
+
+ *pnum += n;
+ sector_num += n;
+ nb_sectors -= n;
+ next = start + (*pnum * BDRV_SECTOR_SIZE);
+
+ if (nb_sectors == 0) {
+ break;
+ }
+
+ offset = get_sector_offset(bs, sector_num, 0);
+ } while ((allocated && offset == next) || (!allocated && offset == -1));
+
+ if (allocated) {
+ return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | start;
+ } else {
+ return 0;
+ }
+}
+
/*
* Calculates the number of cylinders, heads and sectors per cylinder
* based on a given number of sectors. This is the algorithm described
@@ -903,8 +948,9 @@ static BlockDriver bdrv_vpc = {
.bdrv_reopen_prepare = vpc_reopen_prepare,
.bdrv_create = vpc_create,
- .bdrv_read = vpc_co_read,
- .bdrv_write = vpc_co_write,
+ .bdrv_read = vpc_co_read,
+ .bdrv_write = vpc_co_write,
+ .bdrv_co_get_block_status = vpc_co_get_block_status,
.bdrv_get_info = vpc_get_info,
--
2.1.0
