/* if no id is provided, a new one is constructed */ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info) { BDRVQcowState *s = bs->opaque; QCowSnapshot *snapshots1, sn1, *sn = &sn1; int i, ret; uint64_t *l1_table = NULL; memset(sn, 0, sizeof(*sn)); if (sn_info->id_str[0] == '\0') { /* compute a new id */ find_new_snapshot_id(bs, sn_info->id_str, sizeof(sn_info->id_str)); } /* check that the ID is unique */ if (find_snapshot_by_id(bs, sn_info->id_str) >= 0) return -ENOENT; sn->id_str = qemu_strdup(sn_info->id_str); if (!sn->id_str) goto fail; sn->name = qemu_strdup(sn_info->name); if (!sn->name) goto fail; sn->vm_state_size = sn_info->vm_state_size; sn->date_sec = sn_info->date_sec; sn->date_nsec = sn_info->date_nsec; sn->vm_clock_nsec = sn_info->vm_clock_nsec; ret = qcow2_update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 1); if (ret < 0) goto fail; /* create the L1 table of the snapshot */ sn->l1_table_offset = qcow2_alloc_clusters(bs, s->l1_size * sizeof(uint64_t)); sn->l1_size = s->l1_size; l1_table = qemu_malloc(s->l1_size * sizeof(uint64_t)); for(i = 0; i < s->l1_size; i++) { l1_table[i] = cpu_to_be64(s->l1_table[i]); } if (bdrv_pwrite(s->hd, sn->l1_table_offset, l1_table, s->l1_size * sizeof(uint64_t)) != (s->l1_size * sizeof(uint64_t))) goto fail; qemu_free(l1_table); l1_table = NULL; snapshots1 = qemu_malloc((s->nb_snapshots + 1) * sizeof(QCowSnapshot)); if (s->snapshots) { memcpy(snapshots1, s->snapshots, s->nb_snapshots * sizeof(QCowSnapshot)); qemu_free(s->snapshots); } s->snapshots = snapshots1; s->snapshots[s->nb_snapshots++] = *sn; if (qcow_write_snapshots(bs) < 0) goto fail; #ifdef DEBUG_ALLOC qcow2_check_refcounts(bs); #endif return 0; fail: qemu_free(sn->name); qemu_free(l1_table); return -1; }
/* add at the end of the file a new list of snapshots */ static int qcow_write_snapshots(BlockDriverState *bs) { BDRVQcowState *s = bs->opaque; QCowSnapshot *sn; QCowSnapshotHeader h; int i, name_size, id_str_size, snapshots_size; uint64_t data64; uint32_t data32; int64_t offset, snapshots_offset; /* compute the size of the snapshots */ offset = 0; for(i = 0; i < s->nb_snapshots; i++) { sn = s->snapshots + i; offset = align_offset(offset, 8); offset += sizeof(h); offset += strlen(sn->id_str); offset += strlen(sn->name); } snapshots_size = offset; snapshots_offset = qcow2_alloc_clusters(bs, snapshots_size); offset = snapshots_offset; for(i = 0; i < s->nb_snapshots; i++) { sn = s->snapshots + i; memset(&h, 0, sizeof(h)); h.l1_table_offset = cpu_to_be64(sn->l1_table_offset); h.l1_size = cpu_to_be32(sn->l1_size); h.vm_state_size = cpu_to_be32(sn->vm_state_size); h.date_sec = cpu_to_be32(sn->date_sec); h.date_nsec = cpu_to_be32(sn->date_nsec); h.vm_clock_nsec = cpu_to_be64(sn->vm_clock_nsec); id_str_size = strlen(sn->id_str); name_size = strlen(sn->name); h.id_str_size = cpu_to_be16(id_str_size); h.name_size = cpu_to_be16(name_size); offset = align_offset(offset, 8); if (bdrv_pwrite(s->hd, offset, &h, sizeof(h)) != sizeof(h)) goto fail; offset += sizeof(h); if (bdrv_pwrite(s->hd, offset, sn->id_str, id_str_size) != id_str_size) goto fail; offset += id_str_size; if (bdrv_pwrite(s->hd, offset, sn->name, name_size) != name_size) goto fail; offset += name_size; } /* update the various header fields */ data64 = cpu_to_be64(snapshots_offset); if (bdrv_pwrite(s->hd, offsetof(QCowHeader, snapshots_offset), &data64, sizeof(data64)) != sizeof(data64)) goto fail; data32 = cpu_to_be32(s->nb_snapshots); if (bdrv_pwrite(s->hd, offsetof(QCowHeader, nb_snapshots), &data32, sizeof(data32)) != sizeof(data32)) goto fail; /* free the old snapshot table */ qcow2_free_clusters(bs, s->snapshots_offset, s->snapshots_size); s->snapshots_offset = snapshots_offset; s->snapshots_size = snapshots_size; return 0; fail: return -1; }
/* add at the end of the file a new list of snapshots */ static int qcow2_write_snapshots(BlockDriverState *bs) { BDRVQcowState *s = bs->opaque; QCowSnapshot *sn; QCowSnapshotHeader h; QCowSnapshotExtraData extra; int i, name_size, id_str_size, snapshots_size; struct { uint32_t nb_snapshots; uint64_t snapshots_offset; } QEMU_PACKED header_data; int64_t offset, snapshots_offset; int ret; /* compute the size of the snapshots */ offset = 0; for(i = 0; i < s->nb_snapshots; i++) { sn = s->snapshots + i; offset = align_offset(offset, 8); offset += sizeof(h); offset += sizeof(extra); offset += strlen(sn->id_str); offset += strlen(sn->name); } snapshots_size = offset; /* Allocate space for the new snapshot list */ snapshots_offset = qcow2_alloc_clusters(bs, snapshots_size); offset = snapshots_offset; if (offset < 0) { return offset; } ret = bdrv_flush(bs); if (ret < 0) { return ret; } /* The snapshot list position has not yet been updated, so these clusters * must indeed be completely free */ ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT, offset, s->snapshots_size); if (ret < 0) { return ret; } /* Write all snapshots to the new list */ for(i = 0; i < s->nb_snapshots; i++) { sn = s->snapshots + i; memset(&h, 0, sizeof(h)); h.l1_table_offset = cpu_to_be64(sn->l1_table_offset); h.l1_size = cpu_to_be32(sn->l1_size); /* If it doesn't fit in 32 bit, older implementations should treat it * as a disk-only snapshot rather than truncate the VM state */ if (sn->vm_state_size <= 0xffffffff) { h.vm_state_size = cpu_to_be32(sn->vm_state_size); } h.date_sec = cpu_to_be32(sn->date_sec); h.date_nsec = cpu_to_be32(sn->date_nsec); h.vm_clock_nsec = cpu_to_be64(sn->vm_clock_nsec); h.extra_data_size = cpu_to_be32(sizeof(extra)); memset(&extra, 0, sizeof(extra)); extra.vm_state_size_large = cpu_to_be64(sn->vm_state_size); extra.disk_size = cpu_to_be64(sn->disk_size); id_str_size = strlen(sn->id_str); name_size = strlen(sn->name); h.id_str_size = cpu_to_be16(id_str_size); h.name_size = cpu_to_be16(name_size); offset = align_offset(offset, 8); ret = bdrv_pwrite(bs->file, offset, &h, sizeof(h)); if (ret < 0) { goto fail; } offset += sizeof(h); ret = bdrv_pwrite(bs->file, offset, &extra, sizeof(extra)); if (ret < 0) { goto fail; } offset += sizeof(extra); ret = bdrv_pwrite(bs->file, offset, sn->id_str, id_str_size); if (ret < 0) { goto fail; } offset += id_str_size; ret = bdrv_pwrite(bs->file, offset, sn->name, name_size); if (ret < 0) { goto fail; } offset += name_size; } /* * Update the header to point to the new snapshot table. This requires the * new table and its refcounts to be stable on disk. */ ret = bdrv_flush(bs); if (ret < 0) { goto fail; } QEMU_BUILD_BUG_ON(offsetof(QCowHeader, snapshots_offset) != offsetof(QCowHeader, nb_snapshots) + sizeof(header_data.nb_snapshots)); header_data.nb_snapshots = cpu_to_be32(s->nb_snapshots); header_data.snapshots_offset = cpu_to_be64(snapshots_offset); ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, nb_snapshots), &header_data, sizeof(header_data)); if (ret < 0) { goto fail; } /* free the old snapshot table */ qcow2_free_clusters(bs, s->snapshots_offset, s->snapshots_size, QCOW2_DISCARD_SNAPSHOT); s->snapshots_offset = snapshots_offset; s->snapshots_size = snapshots_size; return 0; fail: return ret; }
/* if no id is provided, a new one is constructed */ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info) { BDRVQcowState *s = bs->opaque; QCowSnapshot *new_snapshot_list = NULL; QCowSnapshot *old_snapshot_list = NULL; QCowSnapshot sn1, *sn = &sn1; int i, ret; uint64_t *l1_table = NULL; int64_t l1_table_offset; memset(sn, 0, sizeof(*sn)); /* Generate an ID if it wasn't passed */ if (sn_info->id_str[0] == '\0') { find_new_snapshot_id(bs, sn_info->id_str, sizeof(sn_info->id_str)); } /* Check that the ID is unique */ if (find_snapshot_by_id(bs, sn_info->id_str) >= 0) { return -EEXIST; } /* Populate sn with passed data */ sn->id_str = g_strdup(sn_info->id_str); sn->name = g_strdup(sn_info->name); sn->disk_size = bs->total_sectors * BDRV_SECTOR_SIZE; sn->vm_state_size = sn_info->vm_state_size; sn->date_sec = sn_info->date_sec; sn->date_nsec = sn_info->date_nsec; sn->vm_clock_nsec = sn_info->vm_clock_nsec; /* Allocate the L1 table of the snapshot and copy the current one there. */ l1_table_offset = qcow2_alloc_clusters(bs, s->l1_size * sizeof(uint64_t)); if (l1_table_offset < 0) { ret = l1_table_offset; goto fail; } sn->l1_table_offset = l1_table_offset; sn->l1_size = s->l1_size; l1_table = g_malloc(s->l1_size * sizeof(uint64_t)); for(i = 0; i < s->l1_size; i++) { l1_table[i] = cpu_to_be64(s->l1_table[i]); } ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT, sn->l1_table_offset, s->l1_size * sizeof(uint64_t)); if (ret < 0) { goto fail; } ret = bdrv_pwrite(bs->file, sn->l1_table_offset, l1_table, s->l1_size * sizeof(uint64_t)); if (ret < 0) { goto fail; } g_free(l1_table); l1_table = NULL; /* * Increase the refcounts of all clusters and make sure everything is * stable on disk before updating the snapshot table to contain a pointer * to the new L1 table. */ ret = qcow2_update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 1); if (ret < 0) { goto fail; } /* Append the new snapshot to the snapshot list */ new_snapshot_list = g_malloc((s->nb_snapshots + 1) * sizeof(QCowSnapshot)); if (s->snapshots) { memcpy(new_snapshot_list, s->snapshots, s->nb_snapshots * sizeof(QCowSnapshot)); old_snapshot_list = s->snapshots; } s->snapshots = new_snapshot_list; s->snapshots[s->nb_snapshots++] = *sn; ret = qcow2_write_snapshots(bs); if (ret < 0) { g_free(s->snapshots); s->snapshots = old_snapshot_list; goto fail; } g_free(old_snapshot_list); #ifdef DEBUG_ALLOC { BdrvCheckResult result = {0}; qcow2_check_refcounts(bs, &result, 0); } #endif return 0; fail: g_free(sn->id_str); g_free(sn->name); g_free(l1_table); return ret; }
/* if no id is provided, a new one is constructed */ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info) { BDRVQcow2State *s = bs->opaque; QCowSnapshot *new_snapshot_list = NULL; QCowSnapshot *old_snapshot_list = NULL; QCowSnapshot sn1, *sn = &sn1; int i, ret; uint64_t *l1_table = NULL; int64_t l1_table_offset; if (s->nb_snapshots >= QCOW_MAX_SNAPSHOTS) { return -EFBIG; } memset(sn, 0, sizeof(*sn)); /* Generate an ID */ find_new_snapshot_id(bs, sn_info->id_str, sizeof(sn_info->id_str)); /* Check that the ID is unique */ if (find_snapshot_by_id_and_name(bs, sn_info->id_str, NULL) >= 0) { return -EEXIST; } /* Populate sn with passed data */ sn->id_str = g_strdup(sn_info->id_str); sn->name = g_strdup(sn_info->name); sn->disk_size = bs->total_sectors * BDRV_SECTOR_SIZE; sn->vm_state_size = sn_info->vm_state_size; sn->date_sec = sn_info->date_sec; sn->date_nsec = sn_info->date_nsec; sn->vm_clock_nsec = sn_info->vm_clock_nsec; /* Allocate the L1 table of the snapshot and copy the current one there. */ l1_table_offset = qcow2_alloc_clusters(bs, s->l1_size * sizeof(uint64_t)); if (l1_table_offset < 0) { ret = l1_table_offset; goto fail; } sn->l1_table_offset = l1_table_offset; sn->l1_size = s->l1_size; l1_table = g_try_new(uint64_t, s->l1_size); if (s->l1_size && l1_table == NULL) { ret = -ENOMEM; goto fail; } for(i = 0; i < s->l1_size; i++) { l1_table[i] = cpu_to_be64(s->l1_table[i]); } ret = qcow2_pre_write_overlap_check(bs, 0, sn->l1_table_offset, s->l1_size * sizeof(uint64_t)); if (ret < 0) { goto fail; } ret = bdrv_pwrite(bs->file->bs, sn->l1_table_offset, l1_table, s->l1_size * sizeof(uint64_t)); if (ret < 0) { goto fail; } g_free(l1_table); l1_table = NULL; /* * Increase the refcounts of all clusters and make sure everything is * stable on disk before updating the snapshot table to contain a pointer * to the new L1 table. */ ret = qcow2_update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 1); if (ret < 0) { goto fail; } /* Append the new snapshot to the snapshot list */ new_snapshot_list = g_new(QCowSnapshot, s->nb_snapshots + 1); if (s->snapshots) { memcpy(new_snapshot_list, s->snapshots, s->nb_snapshots * sizeof(QCowSnapshot)); old_snapshot_list = s->snapshots; } s->snapshots = new_snapshot_list; s->snapshots[s->nb_snapshots++] = *sn; ret = qcow2_write_snapshots(bs); if (ret < 0) { g_free(s->snapshots); s->snapshots = old_snapshot_list; s->nb_snapshots--; goto fail; } g_free(old_snapshot_list); /* The VM state isn't needed any more in the active L1 table; in fact, it * hurts by causing expensive COW for the next snapshot. */ qcow2_discard_clusters(bs, qcow2_vm_state_offset(s), align_offset(sn->vm_state_size, s->cluster_size) >> BDRV_SECTOR_BITS, QCOW2_DISCARD_NEVER, false); #ifdef DEBUG_ALLOC { BdrvCheckResult result = {0}; qcow2_check_refcounts(bs, &result, 0); } #endif return 0; fail: g_free(sn->id_str); g_free(sn->name); g_free(l1_table); return ret; }