/* * Block driver for the QCOW format * * Copyright (c) 2004-2006 Fabrice Bellard * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ #include "qemu/osdep.h" #include "qapi/error.h" #include "qemu/error-report.h" #include "block/block_int.h" #include "block/qdict.h" #include "sysemu/block-backend.h" #include "qemu/module.h" #include "qemu/option.h" #include "qemu/bswap.h" #include "qemu/cutils.h" #include "qemu/memalign.h" #include #include "qapi/qmp/qdict.h" #include "qapi/qmp/qstring.h" #include "qapi/qobject-input-visitor.h" #include "qapi/qapi-visit-block-core.h" #include "crypto/block.h" #include "migration/blocker.h" #include "crypto.h" /**************************************************************/ /* QEMU COW block driver with compression and encryption support */ #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb) #define QCOW_VERSION 1 #define QCOW_CRYPT_NONE 0 #define QCOW_CRYPT_AES 1 #define QCOW_OFLAG_COMPRESSED (1LL << 63) typedef struct QCowHeader { uint32_t magic; uint32_t version; uint64_t backing_file_offset; uint32_t backing_file_size; uint32_t mtime; uint64_t size; /* in bytes */ uint8_t cluster_bits; uint8_t l2_bits; uint16_t padding; uint32_t crypt_method; uint64_t l1_table_offset; } QEMU_PACKED QCowHeader; #define L2_CACHE_SIZE 16 typedef struct BDRVQcowState { int cluster_bits; int cluster_size; int l2_bits; int l2_size; unsigned int l1_size; uint64_t cluster_offset_mask; uint64_t l1_table_offset; uint64_t *l1_table; uint64_t *l2_cache; uint64_t l2_cache_offsets[L2_CACHE_SIZE]; uint32_t l2_cache_counts[L2_CACHE_SIZE]; uint8_t *cluster_cache; uint8_t *cluster_data; uint64_t cluster_cache_offset; QCryptoBlock *crypto; /* Disk encryption format driver */ uint32_t crypt_method_header; CoMutex lock; Error *migration_blocker; } BDRVQcowState; static QemuOptsList qcow_create_opts; static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset); static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename) { const QCowHeader *cow_header = (const void *)buf; if (buf_size >= sizeof(QCowHeader) && be32_to_cpu(cow_header->magic) == QCOW_MAGIC && be32_to_cpu(cow_header->version) == QCOW_VERSION) return 100; else return 0; } static int qcow_open(BlockDriverState *bs, QDict *options, int flags, Error **errp) { BDRVQcowState *s = bs->opaque; unsigned int len, i, shift; int ret; QCowHeader header; QCryptoBlockOpenOptions *crypto_opts = NULL; unsigned int cflags = 0; QDict *encryptopts = NULL; const char *encryptfmt; qdict_extract_subqdict(options, &encryptopts, "encrypt."); encryptfmt = qdict_get_try_str(encryptopts, "format"); bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds, BDRV_CHILD_IMAGE, false, errp); if (!bs->file) { ret = -EINVAL; goto fail; } ret = bdrv_pread(bs->file, 0, sizeof(header), &header, 0); if (ret < 0) { goto fail; } header.magic = be32_to_cpu(header.magic); header.version = be32_to_cpu(header.version); header.backing_file_offset = be64_to_cpu(header.backing_file_offset); header.backing_file_size = be32_to_cpu(header.backing_file_size); header.mtime = be32_to_cpu(header.mtime); header.size = be64_to_cpu(header.size); header.crypt_method = be32_to_cpu(header.crypt_method); header.l1_table_offset = be64_to_cpu(header.l1_table_offset); if (header.magic != QCOW_MAGIC) { error_setg(errp, "Image not in qcow format"); ret = -EINVAL; goto fail; } if (header.version != QCOW_VERSION) { error_setg(errp, "qcow (v%d) does not support qcow version %" PRIu32, QCOW_VERSION, header.version); if (header.version == 2 || header.version == 3) { error_append_hint(errp, "Try the 'qcow2' driver instead.\n"); } ret = -ENOTSUP; goto fail; } if (header.size <= 1) { error_setg(errp, "Image size is too small (must be at least 2 bytes)"); ret = -EINVAL; goto fail; } if (header.cluster_bits < 9 || header.cluster_bits > 16) { error_setg(errp, "Cluster size must be between 512 and 64k"); ret = -EINVAL; goto fail; } /* l2_bits specifies number of entries; storing a uint64_t in each entry, * so bytes = num_entries << 3. */ if (header.l2_bits < 9 - 3 || header.l2_bits > 16 - 3) { error_setg(errp, "L2 table size must be between 512 and 64k"); ret = -EINVAL; goto fail; } s->crypt_method_header = header.crypt_method; if (s->crypt_method_header) { if (bdrv_uses_whitelist() && s->crypt_method_header == QCOW_CRYPT_AES) { error_setg(errp, "Use of AES-CBC encrypted qcow images is no longer " "supported in system emulators"); error_append_hint(errp, "You can use 'qemu-img convert' to convert your " "image to an alternative supported format, such " "as unencrypted qcow, or raw with the LUKS " "format instead.\n"); ret = -ENOSYS; goto fail; } if (s->crypt_method_header == QCOW_CRYPT_AES) { if (encryptfmt && !g_str_equal(encryptfmt, "aes")) { error_setg(errp, "Header reported 'aes' encryption format but " "options specify '%s'", encryptfmt); ret = -EINVAL; goto fail; } qdict_put_str(encryptopts, "format", "qcow"); crypto_opts = block_crypto_open_opts_init(encryptopts, errp); if (!crypto_opts) { ret = -EINVAL; goto fail; } if (flags & BDRV_O_NO_IO) { cflags |= QCRYPTO_BLOCK_OPEN_NO_IO; } s->crypto = qcrypto_block_open(crypto_opts, "encrypt.", NULL, NULL, cflags, 1, errp); if (!s->crypto) { ret = -EINVAL; goto fail; } } else { error_setg(errp, "invalid encryption method in qcow header"); ret = -EINVAL; goto fail; } bs->encrypted = true; } else { if (encryptfmt) { error_setg(errp, "No encryption in image header, but options " "specified format '%s'", encryptfmt); ret = -EINVAL; goto fail; } } s->cluster_bits = header.cluster_bits; s->cluster_size = 1 << s->cluster_bits; s->l2_bits = header.l2_bits; s->l2_size = 1 << s->l2_bits; bs->total_sectors = header.size / 512; s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1; /* read the level 1 table */ shift = s->cluster_bits + s->l2_bits; if (header.size > UINT64_MAX - (1LL << shift)) { error_setg(errp, "Image too large"); ret = -EINVAL; goto fail; } else { uint64_t l1_size = (header.size + (1LL << shift) - 1) >> shift; if (l1_size > INT_MAX / sizeof(uint64_t)) { error_setg(errp, "Image too large"); ret = -EINVAL; goto fail; } s->l1_size = l1_size; } s->l1_table_offset = header.l1_table_offset; s->l1_table = g_try_new(uint64_t, s->l1_size); if (s->l1_table == NULL) { error_setg(errp, "Could not allocate memory for L1 table"); ret = -ENOMEM; goto fail; } ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_size * sizeof(uint64_t), s->l1_table, 0); if (ret < 0) { goto fail; } for(i = 0;i < s->l1_size; i++) { s->l1_table[i] = be64_to_cpu(s->l1_table[i]); } /* alloc L2 cache (max. 64k * 16 * 8 = 8 MB) */ s->l2_cache = qemu_try_blockalign(bs->file->bs, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); if (s->l2_cache == NULL) { error_setg(errp, "Could not allocate L2 table cache"); ret = -ENOMEM; goto fail; } s->cluster_cache = g_malloc(s->cluster_size); s->cluster_data = g_malloc(s->cluster_size); s->cluster_cache_offset = -1; /* read the backing file name */ if (header.backing_file_offset != 0) { len = header.backing_file_size; if (len > 1023 || len >= sizeof(bs->backing_file)) { error_setg(errp, "Backing file name too long"); ret = -EINVAL; goto fail; } ret = bdrv_pread(bs->file, header.backing_file_offset, len, bs->auto_backing_file, 0); if (ret < 0) { goto fail; } bs->auto_backing_file[len] = '\0'; pstrcpy(bs->backing_file, sizeof(bs->backing_file), bs->auto_backing_file); } /* Disable migration when qcow images are used */ error_setg(&s->migration_blocker, "The qcow format used by node '%s' " "does not support live migration", bdrv_get_device_or_node_name(bs)); ret = migrate_add_blocker(s->migration_blocker, errp); if (ret < 0) { error_free(s->migration_blocker); goto fail; } qobject_unref(encryptopts); qapi_free_QCryptoBlockOpenOptions(crypto_opts); qemu_co_mutex_init(&s->lock); return 0; fail: g_free(s->l1_table); qemu_vfree(s->l2_cache); g_free(s->cluster_cache); g_free(s->cluster_data); qcrypto_block_free(s->crypto); qobject_unref(encryptopts); qapi_free_QCryptoBlockOpenOptions(crypto_opts); return ret; } /* We have nothing to do for QCOW reopen, stubs just return * success */ static int qcow_reopen_prepare(BDRVReopenState *state, BlockReopenQueue *queue, Error **errp) { return 0; } /* 'allocate' is: * * 0 to not allocate. * * 1 to allocate a normal cluster (for sector-aligned byte offsets 'n_start' * to 'n_end' within the cluster) * * 2 to allocate a compressed cluster of size * 'compressed_size'. 'compressed_size' must be > 0 and < * cluster_size * * return 0 if not allocated, 1 if *result is assigned, and negative * errno on failure. */ static int get_cluster_offset(BlockDriverState *bs, uint64_t offset, int allocate, int compressed_size, int n_start, int n_end, uint64_t *result) { BDRVQcowState *s = bs->opaque; int min_index, i, j, l1_index, l2_index, ret; int64_t l2_offset; uint64_t *l2_table, cluster_offset, tmp; uint32_t min_count; int new_l2_table; *result = 0; l1_index = offset >> (s->l2_bits + s->cluster_bits); l2_offset = s->l1_table[l1_index]; new_l2_table = 0; if (!l2_offset) { if (!allocate) return 0; /* allocate a new l2 entry */ l2_offset = bdrv_getlength(bs->file->bs); if (l2_offset < 0) { return l2_offset; } /* round to cluster size */ l2_offset = QEMU_ALIGN_UP(l2_offset, s->cluster_size); /* update the L1 entry */ s->l1_table[l1_index] = l2_offset; tmp = cpu_to_be64(l2_offset); BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); ret = bdrv_pwrite_sync(bs->file, s->l1_table_offset + l1_index * sizeof(tmp), sizeof(tmp), &tmp, 0); if (ret < 0) { return ret; } new_l2_table = 1; } for(i = 0; i < L2_CACHE_SIZE; i++) { if (l2_offset == s->l2_cache_offsets[i]) { /* increment the hit count */ if (++s->l2_cache_counts[i] == 0xffffffff) { for(j = 0; j < L2_CACHE_SIZE; j++) { s->l2_cache_counts[j] >>= 1; } } l2_table = s->l2_cache + (i << s->l2_bits); goto found; } } /* not found: load a new entry in the least used one */ min_index = 0; min_count = 0xffffffff; for(i = 0; i < L2_CACHE_SIZE; i++) { if (s->l2_cache_counts[i] < min_count) { min_count = s->l2_cache_counts[i]; min_index = i; } } l2_table = s->l2_cache + (min_index << s->l2_bits); BLKDBG_EVENT(bs->file, BLKDBG_L2_LOAD); if (new_l2_table) { memset(l2_table, 0, s->l2_size * sizeof(uint64_t)); ret = bdrv_pwrite_sync(bs->file, l2_offset, s->l2_size * sizeof(uint64_t), l2_table, 0); if (ret < 0) { return ret; } } else { ret = bdrv_pread(bs->file, l2_offset, s->l2_size * sizeof(uint64_t), l2_table, 0); if (ret < 0) { return ret; } } s->l2_cache_offsets[min_index] = l2_offset; s->l2_cache_counts[min_index] = 1; found: l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1); cluster_offset = be64_to_cpu(l2_table[l2_index]); if (!cluster_offset || ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) { if (!allocate) return 0; BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC); assert(QEMU_IS_ALIGNED(n_start | n_end, BDRV_SECTOR_SIZE)); /* allocate a new cluster */ if ((cluster_offset & QCOW_OFLAG_COMPRESSED) && (n_end - n_start) < s->cluster_size) { /* if the cluster is already compressed, we must decompress it in the case it is not completely overwritten */ if (decompress_cluster(bs, cluster_offset) < 0) { return -EIO; } cluster_offset = bdrv_getlength(bs->file->bs); if ((int64_t) cluster_offset < 0) { return cluster_offset; } cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size); /* write the cluster content */ BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); ret = bdrv_pwrite(bs->file, cluster_offset, s->cluster_size, s->cluster_cache, 0); if (ret < 0) { return ret; } } else { cluster_offset = bdrv_getlength(bs->file->bs); if ((int64_t) cluster_offset < 0) { return cluster_offset; } if (allocate == 1) { /* round to cluster size */ cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size); if (cluster_offset + s->cluster_size > INT64_MAX) { return -E2BIG; } ret = bdrv_truncate(bs->file, cluster_offset + s->cluster_size, false, PREALLOC_MODE_OFF, 0, NULL); if (ret < 0) { return ret; } /* if encrypted, we must initialize the cluster content which won't be written */ if (bs->encrypted && (n_end - n_start) < s->cluster_size) { uint64_t start_offset; assert(s->crypto); start_offset = offset & ~(s->cluster_size - 1); for (i = 0; i < s->cluster_size; i += BDRV_SECTOR_SIZE) { if (i < n_start || i >= n_end) { memset(s->cluster_data, 0x00, BDRV_SECTOR_SIZE); if (qcrypto_block_encrypt(s->crypto, start_offset + i, s->cluster_data, BDRV_SECTOR_SIZE, NULL) < 0) { return -EIO; } BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); ret = bdrv_pwrite(bs->file, cluster_offset + i, BDRV_SECTOR_SIZE, s->cluster_data, 0); if (ret < 0) { return ret; } } } } } else if (allocate == 2) { cluster_offset |= QCOW_OFLAG_COMPRESSED | (uint64_t)compressed_size << (63 - s->cluster_bits); } } /* update L2 table */ tmp = cpu_to_be64(cluster_offset); l2_table[l2_index] = tmp; if (allocate == 2) { BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE_COMPRESSED); } else { BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE); } ret = bdrv_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp), sizeof(tmp), &tmp, 0); if (ret < 0) { return ret; } } *result = cluster_offset; return 1; } static int coroutine_fn qcow_co_block_status(BlockDriverState *bs, bool want_zero, int64_t offset, int64_t bytes, int64_t *pnum, int64_t *map, BlockDriverState **file) { BDRVQcowState *s = bs->opaque; int index_in_cluster, ret; int64_t n; uint64_t cluster_offset; qemu_co_mutex_lock(&s->lock); ret = get_cluster_offset(bs, offset, 0, 0, 0, 0, &cluster_offset); qemu_co_mutex_unlock(&s->lock); if (ret < 0) { return ret; } index_in_cluster = offset & (s->cluster_size - 1); n = s->cluster_size - index_in_cluster; if (n > bytes) { n = bytes; } *pnum = n; if (!cluster_offset) { return 0; } if ((cluster_offset & QCOW_OFLAG_COMPRESSED) || s->crypto) { return BDRV_BLOCK_DATA; } *map = cluster_offset | index_in_cluster; *file = bs->file->bs; return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID; } static int decompress_buffer(uint8_t *out_buf, int out_buf_size, const uint8_t *buf, int buf_size) { z_stream strm1, *strm = &strm1; int ret, out_len; memset(strm, 0, sizeof(*strm)); strm->next_in = (uint8_t *)buf; strm->avail_in = buf_size; strm->next_out = out_buf; strm->avail_out = out_buf_size; ret = inflateInit2(strm, -12); if (ret != Z_OK) return -1; ret = inflate(strm, Z_FINISH); out_len = strm->next_out - out_buf; if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) || out_len != out_buf_size) { inflateEnd(strm); return -1; } inflateEnd(strm); return 0; } static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset) { BDRVQcowState *s = bs->opaque; int ret, csize; uint64_t coffset; coffset = cluster_offset & s->cluster_offset_mask; if (s->cluster_cache_offset != coffset) { csize = cluster_offset >> (63 - s->cluster_bits); csize &= (s->cluster_size - 1); BLKDBG_EVENT(bs->file, BLKDBG_READ_COMPRESSED); ret = bdrv_pread(bs->file, coffset, csize, s->cluster_data, 0); if (ret < 0) return -1; if (decompress_buffer(s->cluster_cache, s->cluster_size, s->cluster_data, csize) < 0) { return -1; } s->cluster_cache_offset = coffset; } return 0; } static void qcow_refresh_limits(BlockDriverState *bs, Error **errp) { /* At least encrypted images require 512-byte alignment. Apply the * limit universally, rather than just on encrypted images, as * it's easier to let the block layer handle rounding than to * audit this code further. */ bs->bl.request_alignment = BDRV_SECTOR_SIZE; } static coroutine_fn int qcow_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes, QEMUIOVector *qiov, BdrvRequestFlags flags) { BDRVQcowState *s = bs->opaque; int offset_in_cluster; int ret = 0, n; uint64_t cluster_offset; uint8_t *buf; void *orig_buf; assert(!flags); if (qiov->niov > 1) { buf = orig_buf = qemu_try_blockalign(bs, qiov->size); if (buf == NULL) { return -ENOMEM; } } else { orig_buf = NULL; buf = (uint8_t *)qiov->iov->iov_base; } qemu_co_mutex_lock(&s->lock); while (bytes != 0) { /* prepare next request */ ret = get_cluster_offset(bs, offset, 0, 0, 0, 0, &cluster_offset); if (ret < 0) { break; } offset_in_cluster = offset & (s->cluster_size - 1); n = s->cluster_size - offset_in_cluster; if (n > bytes) { n = bytes; } if (!cluster_offset) { if (bs->backing) { /* read from the base image */ qemu_co_mutex_unlock(&s->lock); /* qcow2 emits this on bs->file instead of bs->backing */ BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO); ret = bdrv_co_pread(bs->backing, offset, n, buf, 0); qemu_co_mutex_lock(&s->lock); if (ret < 0) { break; } } else { /* Note: in this case, no need to wait */ memset(buf, 0, n); } } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) { /* add AIO support for compressed blocks ? */ if (decompress_cluster(bs, cluster_offset) < 0) { ret = -EIO; break; } memcpy(buf, s->cluster_cache + offset_in_cluster, n); } else { if ((cluster_offset & 511) != 0) { ret = -EIO; break; } qemu_co_mutex_unlock(&s->lock); BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); ret = bdrv_co_pread(bs->file, cluster_offset + offset_in_cluster, n, buf, 0); qemu_co_mutex_lock(&s->lock); if (ret < 0) { break; } if (bs->encrypted) { assert(s->crypto); if (qcrypto_block_decrypt(s->crypto, offset, buf, n, NULL) < 0) { ret = -EIO; break; } } } ret = 0; bytes -= n; offset += n; buf += n; } qemu_co_mutex_unlock(&s->lock); if (qiov->niov > 1) { qemu_iovec_from_buf(qiov, 0, orig_buf, qiov->size); qemu_vfree(orig_buf); } return ret; } static coroutine_fn int qcow_co_pwritev(BlockDriverState *bs, int64_t offset, int64_t bytes, QEMUIOVector *qiov, BdrvRequestFlags flags) { BDRVQcowState *s = bs->opaque; int offset_in_cluster; uint64_t cluster_offset; int ret = 0, n; uint8_t *buf; void *orig_buf; assert(!flags); s->cluster_cache_offset = -1; /* disable compressed cache */ /* We must always copy the iov when encrypting, so we * don't modify the original data buffer during encryption */ if (bs->encrypted || qiov->niov > 1) { buf = orig_buf = qemu_try_blockalign(bs, qiov->size); if (buf == NULL) { return -ENOMEM; } qemu_iovec_to_buf(qiov, 0, buf, qiov->size); } else { orig_buf = NULL; buf = (uint8_t *)qiov->iov->iov_base; } qemu_co_mutex_lock(&s->lock); while (bytes != 0) { offset_in_cluster = offset & (s->cluster_size - 1); n = s->cluster_size - offset_in_cluster; if (n > bytes) { n = bytes; } ret = get_cluster_offset(bs, offset, 1, 0, offset_in_cluster, offset_in_cluster + n, &cluster_offset); if (ret < 0) { break; } if (!cluster_offset || (cluster_offset & 511) != 0) { ret = -EIO; break; } if (bs->encrypted) { assert(s->crypto); if (qcrypto_block_encrypt(s->crypto, offset, buf, n, NULL) < 0) { ret = -EIO; break; } } qemu_co_mutex_unlock(&s->lock); BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); ret = bdrv_co_pwrite(bs->file, cluster_offset + offset_in_cluster, n, buf, 0); qemu_co_mutex_lock(&s->lock); if (ret < 0) { break; } ret = 0; bytes -= n; offset += n; buf += n; } qemu_co_mutex_unlock(&s->lock); qemu_vfree(orig_buf); return ret; } static void qcow_close(BlockDriverState *bs) { BDRVQcowState *s = bs->opaque; qcrypto_block_free(s->crypto); s->crypto = NULL; g_free(s->l1_table); qemu_vfree(s->l2_cache); g_free(s->cluster_cache); g_free(s->cluster_data); migrate_del_blocker(s->migration_blocker); error_free(s->migration_blocker); } static int coroutine_fn qcow_co_create(BlockdevCreateOptions *opts, Error **errp) { BlockdevCreateOptionsQcow *qcow_opts; int header_size, backing_filename_len, l1_size, shift, i; QCowHeader header; uint8_t *tmp; int64_t total_size = 0; int ret; BlockDriverState *bs; BlockBackend *qcow_blk; QCryptoBlock *crypto = NULL; assert(opts->driver == BLOCKDEV_DRIVER_QCOW); qcow_opts = &opts->u.qcow; /* Sanity checks */ total_size = qcow_opts->size; if (total_size == 0) { error_setg(errp, "Image size is too small, cannot be zero length"); return -EINVAL; } if (qcow_opts->has_encrypt && qcow_opts->encrypt->format != Q_CRYPTO_BLOCK_FORMAT_QCOW) { error_setg(errp, "Unsupported encryption format"); return -EINVAL; } /* Create BlockBackend to write to the image */ bs = bdrv_open_blockdev_ref(qcow_opts->file, errp); if (bs == NULL) { return -EIO; } qcow_blk = blk_new_with_bs(bs, BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL, errp); if (!qcow_blk) { ret = -EPERM; goto exit; } blk_set_allow_write_beyond_eof(qcow_blk, true); /* Create image format */ memset(&header, 0, sizeof(header)); header.magic = cpu_to_be32(QCOW_MAGIC); header.version = cpu_to_be32(QCOW_VERSION); header.size = cpu_to_be64(total_size); header_size = sizeof(header); backing_filename_len = 0; if (qcow_opts->has_backing_file) { if (strcmp(qcow_opts->backing_file, "fat:")) { header.backing_file_offset = cpu_to_be64(header_size); backing_filename_len = strlen(qcow_opts->backing_file); header.backing_file_size = cpu_to_be32(backing_filename_len); header_size += backing_filename_len; } else { /* special backing file for vvfat */ qcow_opts->has_backing_file = false; } header.cluster_bits = 9; /* 512 byte cluster to avoid copying unmodified sectors */ header.l2_bits = 12; /* 32 KB L2 tables */ } else { header.cluster_bits = 12; /* 4 KB clusters */ header.l2_bits = 9; /* 4 KB L2 tables */ } header_size = (header_size + 7) & ~7; shift = header.cluster_bits + header.l2_bits; l1_size = (total_size + (1LL << shift) - 1) >> shift; header.l1_table_offset = cpu_to_be64(header_size); if (qcow_opts->has_encrypt) { header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES); crypto = qcrypto_block_create(qcow_opts->encrypt, "encrypt.", NULL, NULL, NULL, errp); if (!crypto) { ret = -EINVAL; goto exit; } } else { header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); } /* write all the data */ ret = blk_pwrite(qcow_blk, 0, &header, sizeof(header), 0); if (ret != sizeof(header)) { goto exit; } if (qcow_opts->has_backing_file) { ret = blk_pwrite(qcow_blk, sizeof(header), qcow_opts->backing_file, backing_filename_len, 0); if (ret != backing_filename_len) { goto exit; } } tmp = g_malloc0(BDRV_SECTOR_SIZE); for (i = 0; i < DIV_ROUND_UP(sizeof(uint64_t) * l1_size, BDRV_SECTOR_SIZE); i++) { ret = blk_pwrite(qcow_blk, header_size + BDRV_SECTOR_SIZE * i, tmp, BDRV_SECTOR_SIZE, 0); if (ret != BDRV_SECTOR_SIZE) { g_free(tmp); goto exit; } } g_free(tmp); ret = 0; exit: blk_unref(qcow_blk); bdrv_unref(bs); qcrypto_block_free(crypto); return ret; } static int coroutine_fn qcow_co_create_opts(BlockDriver *drv, const char *filename, QemuOpts *opts, Error **errp) { BlockdevCreateOptions *create_options = NULL; BlockDriverState *bs = NULL; QDict *qdict = NULL; Visitor *v; const char *val; int ret; char *backing_fmt; static const QDictRenames opt_renames[] = { { BLOCK_OPT_BACKING_FILE, "backing-file" }, { BLOCK_OPT_ENCRYPT, BLOCK_OPT_ENCRYPT_FORMAT }, { NULL, NULL }, }; /* * We can't actually store a backing format, but can check that * the user's request made sense. */ backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT); if (backing_fmt && !bdrv_find_format(backing_fmt)) { error_setg(errp, "unrecognized backing format '%s'", backing_fmt); ret = -EINVAL; goto fail; } /* Parse options and convert legacy syntax */ qdict = qemu_opts_to_qdict_filtered(opts, NULL, &qcow_create_opts, true); val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT); if (val && !strcmp(val, "on")) { qdict_put_str(qdict, BLOCK_OPT_ENCRYPT, "qcow"); } else if (val && !strcmp(val, "off")) { qdict_del(qdict, BLOCK_OPT_ENCRYPT); } val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT); if (val && !strcmp(val, "aes")) { qdict_put_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT, "qcow"); } if (!qdict_rename_keys(qdict, opt_renames, errp)) { ret = -EINVAL; goto fail; } /* Create and open the file (protocol layer) */ ret = bdrv_create_file(filename, opts, errp); if (ret < 0) { goto fail; } bs = bdrv_open(filename, NULL, NULL, BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp); if (bs == NULL) { ret = -EIO; goto fail; } /* Now get the QAPI type BlockdevCreateOptions */ qdict_put_str(qdict, "driver", "qcow"); qdict_put_str(qdict, "file", bs->node_name); v = qobject_input_visitor_new_flat_confused(qdict, errp); if (!v) { ret = -EINVAL; goto fail; } visit_type_BlockdevCreateOptions(v, NULL, &create_options, errp); visit_free(v); if (!create_options) { ret = -EINVAL; goto fail; } /* Silently round up size */ assert(create_options->driver == BLOCKDEV_DRIVER_QCOW); create_options->u.qcow.size = ROUND_UP(create_options->u.qcow.size, BDRV_SECTOR_SIZE); /* Create the qcow image (format layer) */ ret = qcow_co_create(create_options, errp); if (ret < 0) { goto fail; } ret = 0; fail: g_free(backing_fmt); qobject_unref(qdict); bdrv_unref(bs); qapi_free_BlockdevCreateOptions(create_options); return ret; } static int qcow_make_empty(BlockDriverState *bs) { BDRVQcowState *s = bs->opaque; uint32_t l1_length = s->l1_size * sizeof(uint64_t); int ret; memset(s->l1_table, 0, l1_length); if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, l1_length, s->l1_table, 0) < 0) return -1; ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length, false, PREALLOC_MODE_OFF, 0, NULL); if (ret < 0) return ret; memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t)); memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t)); return 0; } /* XXX: put compressed sectors first, then all the cluster aligned tables to avoid losing bytes in alignment */ static coroutine_fn int qcow_co_pwritev_compressed(BlockDriverState *bs, int64_t offset, int64_t bytes, QEMUIOVector *qiov) { BDRVQcowState *s = bs->opaque; z_stream strm; int ret, out_len; uint8_t *buf, *out_buf; uint64_t cluster_offset; buf = qemu_blockalign(bs, s->cluster_size); if (bytes != s->cluster_size) { if (bytes > s->cluster_size || offset + bytes != bs->total_sectors << BDRV_SECTOR_BITS) { qemu_vfree(buf); return -EINVAL; } /* Zero-pad last write if image size is not cluster aligned */ memset(buf + bytes, 0, s->cluster_size - bytes); } qemu_iovec_to_buf(qiov, 0, buf, qiov->size); out_buf = g_malloc(s->cluster_size); /* best compression, small window, no zlib header */ memset(&strm, 0, sizeof(strm)); ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, Z_DEFLATED, -12, 9, Z_DEFAULT_STRATEGY); if (ret != 0) { ret = -EINVAL; goto fail; } strm.avail_in = s->cluster_size; strm.next_in = (uint8_t *)buf; strm.avail_out = s->cluster_size; strm.next_out = out_buf; ret = deflate(&strm, Z_FINISH); if (ret != Z_STREAM_END && ret != Z_OK) { deflateEnd(&strm); ret = -EINVAL; goto fail; } out_len = strm.next_out - out_buf; deflateEnd(&strm); if (ret != Z_STREAM_END || out_len >= s->cluster_size) { /* could not compress: write normal cluster */ ret = qcow_co_pwritev(bs, offset, bytes, qiov, 0); if (ret < 0) { goto fail; } goto success; } qemu_co_mutex_lock(&s->lock); ret = get_cluster_offset(bs, offset, 2, out_len, 0, 0, &cluster_offset); qemu_co_mutex_unlock(&s->lock); if (ret < 0) { goto fail; } if (cluster_offset == 0) { ret = -EIO; goto fail; } cluster_offset &= s->cluster_offset_mask; BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED); ret = bdrv_co_pwrite(bs->file, cluster_offset, out_len, out_buf, 0); if (ret < 0) { goto fail; } success: ret = 0; fail: qemu_vfree(buf); g_free(out_buf); return ret; } static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) { BDRVQcowState *s = bs->opaque; bdi->cluster_size = s->cluster_size; return 0; } static QemuOptsList qcow_create_opts = { .name = "qcow-create-opts", .head = QTAILQ_HEAD_INITIALIZER(qcow_create_opts.head), .desc = { { .name = BLOCK_OPT_SIZE, .type = QEMU_OPT_SIZE, .help = "Virtual disk size" }, { .name = BLOCK_OPT_BACKING_FILE, .type = QEMU_OPT_STRING, .help = "File name of a base image" }, { .name = BLOCK_OPT_BACKING_FMT, .type = QEMU_OPT_STRING, .help = "Format of the backing image", }, { .name = BLOCK_OPT_ENCRYPT, .type = QEMU_OPT_BOOL, .help = "Encrypt the image with format 'aes'. (Deprecated " "in favor of " BLOCK_OPT_ENCRYPT_FORMAT "=aes)", }, { .name = BLOCK_OPT_ENCRYPT_FORMAT, .type = QEMU_OPT_STRING, .help = "Encrypt the image, format choices: 'aes'", }, BLOCK_CRYPTO_OPT_DEF_QCOW_KEY_SECRET("encrypt."), { /* end of list */ } } }; static const char *const qcow_strong_runtime_opts[] = { "encrypt." BLOCK_CRYPTO_OPT_QCOW_KEY_SECRET, NULL }; static BlockDriver bdrv_qcow = { .format_name = "qcow", .instance_size = sizeof(BDRVQcowState), .bdrv_probe = qcow_probe, .bdrv_open = qcow_open, .bdrv_close = qcow_close, .bdrv_child_perm = bdrv_default_perms, .bdrv_reopen_prepare = qcow_reopen_prepare, .bdrv_co_create = qcow_co_create, .bdrv_co_create_opts = qcow_co_create_opts, .bdrv_has_zero_init = bdrv_has_zero_init_1, .is_format = true, .supports_backing = true, .bdrv_refresh_limits = qcow_refresh_limits, .bdrv_co_preadv = qcow_co_preadv, .bdrv_co_pwritev = qcow_co_pwritev, .bdrv_co_block_status = qcow_co_block_status, .bdrv_make_empty = qcow_make_empty, .bdrv_co_pwritev_compressed = qcow_co_pwritev_compressed, .bdrv_get_info = qcow_get_info, .create_opts = &qcow_create_opts, .strong_runtime_opts = qcow_strong_runtime_opts, }; static void bdrv_qcow_init(void) { bdrv_register(&bdrv_qcow); } block_init(bdrv_qcow_init);