Hi Stefan, please have a look at
[PATCHv2 1.8 0/9] qemu-img convert optimizations This one here is obsolete. Peter Am 02.12.2013 um 15:13 schrieb Stefan Hajnoczi <[email protected]>: > On Fri, Nov 22, 2013 at 03:48:30PM +0100, Peter Lieven wrote: >> - /* If the output image is being created as a copy on write >> image, >> - assume that sectors which are unallocated in the input image >> - are present in both the output's and input's base images (no >> - need to copy them). */ >> - if (out_baseimg) { >> - ret = bdrv_is_allocated(bs[bs_i], sector_num - bs_offset, >> - n, &n1); > > int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num, > int nb_sectors, int *pnum) > { > int64_t ret = bdrv_get_block_status(bs, sector_num, nb_sectors, pnum); > if (ret < 0) { > return ret; > } > return > (ret & BDRV_BLOCK_DATA) || > ((ret & BDRV_BLOCK_ZERO) && !bdrv_has_zero_init(bs)); > } > > bdrv_has_zero_init() returns false when bs->backing_hd != NULL. > >> + if (out_baseimg || has_zero_init) { >> + n = nb_sectors > INT_MAX ? INT_MAX : nb_sectors; >> + ret = bdrv_get_block_status(bs[bs_i], sector_num - >> bs_offset, >> + n, &n1); >> if (ret < 0) { >> - error_report("error while reading metadata for sector " >> - "%" PRId64 ": %s", >> + error_report("error while reading block status of >> sector %" PRId64 ": %s", >> sector_num - bs_offset, strerror(-ret)); >> goto out; >> } >> - if (!ret) { >> + /* If the output image is zero initialized, we are not >> working >> + * on a shared base and the input is zero we can skip the >> next >> + * n1 bytes */ >> + if (!out_baseimg && has_zero_init && ret & BDRV_BLOCK_ZERO) >> { >> + sector_num += n1; >> + continue; >> + } >> + /* If the output image is being created as a copy on write >> image, >> + assume that sectors which are unallocated in the input >> image >> + are present in both the output's and input's base images >> (no >> + need to copy them). */ >> + if (out_baseimg && !(ret & BDRV_BLOCK_DATA)) { >> sector_num += n1; >> continue; >> } > > How are these two if statements different from bdrv_is_allocated()? > > Stefan
