On Thu 01 Nov 2018 07:27:36 PM CET, Vladimir Sementsov-Ogievskiy wrote: > diff --git a/block/qcow2.c b/block/qcow2.c > index e9d24b801e..950b9f7ec6 100644 > --- a/block/qcow2.c > +++ b/block/qcow2.c > @@ -3956,14 +3956,15 @@ fail: > int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset) > { > BDRVQcow2State *s = bs->opaque; > - int ret, csize, nb_csectors, sector_offset; > + int ret, csize, nb_csectors; > uint64_t coffset; > + struct iovec iov; > + QEMUIOVector local_qiov; > > coffset = cluster_offset & s->cluster_offset_mask; > if (s->cluster_cache_offset != coffset) { > nb_csectors = ((cluster_offset >> s->csize_shift) & s->csize_mask) + > 1; > - sector_offset = coffset & 511; > - csize = nb_csectors * 512 - sector_offset; > + csize = nb_csectors * 512 - (coffset & 511); > > /* Allocate buffers on first decompress operation, most images are > * uncompressed and the memory overhead can be avoided. The buffers > @@ -3981,14 +3982,17 @@ int qcow2_decompress_cluster(BlockDriverState *bs, > uint64_t cluster_offset) > s->cluster_cache = g_malloc(s->cluster_size); > } > > + iov.iov_base = s->cluster_data; > + iov.iov_len = csize; > + qemu_iovec_init_external(&local_qiov, &iov, 1); > + > BLKDBG_EVENT(bs->file, BLKDBG_READ_COMPRESSED); > - ret = bdrv_read(bs->file, coffset >> 9, s->cluster_data, > - nb_csectors); > + ret = bdrv_co_preadv(bs->file, coffset, csize, &local_qiov, > 0);
I think you should annotate the function with coroutine_fn or use bdrv_pread() instead. Berto