diff options
Diffstat (limited to 'block/qcow2.c')
| -rw-r--r-- | block/qcow2.c | 100 |
1 files changed, 99 insertions, 1 deletions
diff --git a/block/qcow2.c b/block/qcow2.c index 46edea8dec..c144ea5620 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -3093,7 +3093,9 @@ static int qcow2_truncate(BlockDriverState *bs, int64_t offset, int64_t new_l1_size; int ret; - if (prealloc != PREALLOC_MODE_OFF && prealloc != PREALLOC_MODE_METADATA) { + if (prealloc != PREALLOC_MODE_OFF && prealloc != PREALLOC_MODE_METADATA && + prealloc != PREALLOC_MODE_FALLOC && prealloc != PREALLOC_MODE_FULL) + { error_setg(errp, "Unsupported preallocation mode '%s'", PreallocMode_lookup[prealloc]); return -ENOTSUP; @@ -3144,6 +3146,102 @@ static int qcow2_truncate(BlockDriverState *bs, int64_t offset, } break; + case PREALLOC_MODE_FALLOC: + case PREALLOC_MODE_FULL: + { + int64_t allocation_start, host_offset, guest_offset; + int64_t clusters_allocated; + int64_t old_file_size, new_file_size; + uint64_t nb_new_data_clusters, nb_new_l2_tables; + + old_file_size = bdrv_getlength(bs->file->bs); + if (old_file_size < 0) { + error_setg_errno(errp, -old_file_size, + "Failed to inquire current file length"); + return ret; + } + + nb_new_data_clusters = DIV_ROUND_UP(offset - old_length, + s->cluster_size); + + /* This is an overestimation; we will not actually allocate space for + * these in the file but just make sure the new refcount structures are + * able to cover them so we will not have to allocate new refblocks + * while entering the data blocks in the potentially new L2 tables. + * (We do not actually care where the L2 tables are placed. Maybe they + * are already allocated or they can be placed somewhere before + * @old_file_size. It does not matter because they will be fully + * allocated automatically, so they do not need to be covered by the + * preallocation. All that matters is that we will not have to allocate + * new refcount structures for them.) */ + nb_new_l2_tables = DIV_ROUND_UP(nb_new_data_clusters, + s->cluster_size / sizeof(uint64_t)); + /* The cluster range may not be aligned to L2 boundaries, so add one L2 + * table for a potential head/tail */ + nb_new_l2_tables++; + + allocation_start = qcow2_refcount_area(bs, old_file_size, + nb_new_data_clusters + + nb_new_l2_tables, + true, 0, 0); + if (allocation_start < 0) { + error_setg_errno(errp, -allocation_start, + "Failed to resize refcount structures"); + return -allocation_start; + } + + clusters_allocated = qcow2_alloc_clusters_at(bs, allocation_start, + nb_new_data_clusters); + if (clusters_allocated < 0) { + error_setg_errno(errp, -clusters_allocated, + "Failed to allocate data clusters"); + return -clusters_allocated; + } + + assert(clusters_allocated == nb_new_data_clusters); + + /* Allocate the data area */ + new_file_size = allocation_start + + nb_new_data_clusters * s->cluster_size; + ret = bdrv_truncate(bs->file, new_file_size, prealloc, errp); + if (ret < 0) { + error_prepend(errp, "Failed to resize underlying file: "); + qcow2_free_clusters(bs, allocation_start, + nb_new_data_clusters * s->cluster_size, + QCOW2_DISCARD_OTHER); + return ret; + } + + /* Create the necessary L2 entries */ + host_offset = allocation_start; + guest_offset = old_length; + while (nb_new_data_clusters) { + int64_t guest_cluster = guest_offset >> s->cluster_bits; + int64_t nb_clusters = MIN(nb_new_data_clusters, + s->l2_size - guest_cluster % s->l2_size); + QCowL2Meta allocation = { + .offset = guest_offset, + .alloc_offset = host_offset, + .nb_clusters = nb_clusters, + }; + qemu_co_queue_init(&allocation.dependent_requests); + + ret = qcow2_alloc_cluster_link_l2(bs, &allocation); + if (ret < 0) { + error_setg_errno(errp, -ret, "Failed to update L2 tables"); + qcow2_free_clusters(bs, host_offset, + nb_new_data_clusters * s->cluster_size, + QCOW2_DISCARD_OTHER); + return ret; + } + + guest_offset += nb_clusters * s->cluster_size; + host_offset += nb_clusters * s->cluster_size; + nb_new_data_clusters -= nb_clusters; + } + break; + } + default: g_assert_not_reached(); } |