static int bdrv_qed_open(BlockDriverState *bs, QDict *options, int flags, Error **errp) { BDRVQEDState *s = bs->opaque; QEDHeader le_header; int64_t file_size; int ret; s->bs = bs; QSIMPLEQ_INIT(&s->allocating_write_reqs); ret = bdrv_pread(bs->file, 0, &le_header, sizeof(le_header)); if (ret < 0) { return ret; } qed_header_le_to_cpu(&le_header, &s->header); if (s->header.magic != QED_MAGIC) { error_setg(errp, "Image not in QED format"); return -EINVAL; } if (s->header.features & ~QED_FEATURE_MASK) { /* image uses unsupported feature bits */ char buf[64]; snprintf(buf, sizeof(buf), "%" PRIx64, s->header.features & ~QED_FEATURE_MASK); error_set(errp, QERR_UNKNOWN_BLOCK_FORMAT_FEATURE, bdrv_get_device_name(bs), "QED", buf); return -ENOTSUP; } if (!qed_is_cluster_size_valid(s->header.cluster_size)) { return -EINVAL; } /* Round down file size to the last cluster */ file_size = bdrv_getlength(bs->file); if (file_size < 0) { return file_size; } s->file_size = qed_start_of_cluster(s, file_size); if (!qed_is_table_size_valid(s->header.table_size)) { return -EINVAL; } if (!qed_is_image_size_valid(s->header.image_size, s->header.cluster_size, s->header.table_size)) { return -EINVAL; } if (!qed_check_table_offset(s, s->header.l1_table_offset)) { return -EINVAL; } s->table_nelems = (s->header.cluster_size * s->header.table_size) / sizeof(uint64_t); s->l2_shift = ffs(s->header.cluster_size) - 1; s->l2_mask = s->table_nelems - 1; s->l1_shift = s->l2_shift + ffs(s->table_nelems) - 1; /* Header size calculation must not overflow uint32_t */ if (s->header.header_size > UINT32_MAX / s->header.cluster_size) { return -EINVAL; } if ((s->header.features & QED_F_BACKING_FILE)) { if ((uint64_t)s->header.backing_filename_offset + s->header.backing_filename_size > s->header.cluster_size * s->header.header_size) { return -EINVAL; } ret = qed_read_string(bs->file, s->header.backing_filename_offset, s->header.backing_filename_size, bs->backing_file, sizeof(bs->backing_file)); if (ret < 0) { return ret; } if (s->header.features & QED_F_BACKING_FORMAT_NO_PROBE) { pstrcpy(bs->backing_format, sizeof(bs->backing_format), "raw"); } } /* Reset unknown autoclear feature bits. This is a backwards * compatibility mechanism that allows images to be opened by older * programs, which "knock out" unknown feature bits. When an image is * opened by a newer program again it can detect that the autoclear * feature is no longer valid. */ if ((s->header.autoclear_features & ~QED_AUTOCLEAR_FEATURE_MASK) != 0 && !bdrv_is_read_only(bs->file) && !(flags & BDRV_O_INCOMING)) { s->header.autoclear_features &= QED_AUTOCLEAR_FEATURE_MASK; ret = qed_write_header_sync(s); if (ret) { return ret; } /* From here on only known autoclear feature bits are valid */ bdrv_flush(bs->file); } s->l1_table = qed_alloc_table(s); qed_init_l2_cache(&s->l2_cache); ret = qed_read_l1_table_sync(s); if (ret) { goto out; } /* If image was not closed cleanly, check consistency */ if (!(flags & BDRV_O_CHECK) && (s->header.features & QED_F_NEED_CHECK)) { /* Read-only images cannot be fixed. There is no risk of corruption * since write operations are not possible. Therefore, allow * potentially inconsistent images to be opened read-only. This can * aid data recovery from an otherwise inconsistent image. */ if (!bdrv_is_read_only(bs->file) && !(flags & BDRV_O_INCOMING)) { BdrvCheckResult result = {0}; ret = qed_check(s, &result, true); if (ret) { goto out; } } } bdrv_qed_attach_aio_context(bs, bdrv_get_aio_context(bs)); out: if (ret) { qed_free_l2_cache(&s->l2_cache); qemu_vfree(s->l1_table); } return ret; }