/* * 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 "qemu-common.h" #include "block/block_int.h" #include "sysemu/block-backend.h" #include "qemu/module.h" #include #include "qapi/qmp/qerror.h" #include "crypto/cipher.h" #include "migration/migration.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 cluster_sectors; 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; QCryptoCipher *cipher; /* NULL if no key yet */ uint32_t crypt_method_header; CoMutex lock; Error *migration_blocker; } BDRVQcowState; 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; ret = bdrv_pread(bs->file->bs, 0, &header, sizeof(header)); if (ret < 0) { goto fail; } be32_to_cpus(&header.magic); be32_to_cpus(&header.version); be64_to_cpus(&header.backing_file_offset); be32_to_cpus(&header.backing_file_size); be32_to_cpus(&header.mtime); be64_to_cpus(&header.size); be32_to_cpus(&header.crypt_method); be64_to_cpus(&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) { char version[64]; snprintf(version, sizeof(version), "QCOW version %" PRIu32, header.version); error_setg(errp, QERR_UNKNOWN_BLOCK_FORMAT_FEATURE, bdrv_get_device_or_node_name(bs), "qcow", version); 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; } if (header.crypt_method > QCOW_CRYPT_AES) { error_setg(errp, "invalid encryption method in qcow header"); ret = -EINVAL; goto fail; } if (!qcrypto_cipher_supports(QCRYPTO_CIPHER_ALG_AES_128)) { error_setg(errp, "AES cipher not available"); ret = -EINVAL; goto fail; } s->crypt_method_header = header.crypt_method; if (s->crypt_method_header) { bs->encrypted = 1; } s->cluster_bits = header.cluster_bits; s->cluster_size = 1 << s->cluster_bits; s->cluster_sectors = 1 << (s->cluster_bits - 9); 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->bs, s->l1_table_offset, s->l1_table, s->l1_size * sizeof(uint64_t)); if (ret < 0) { goto fail; } for(i = 0;i < s->l1_size; i++) { be64_to_cpus(&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->bs, header.backing_file_offset, bs->backing_file, len); if (ret < 0) { goto fail; } bs->backing_file[len] = '\0'; } /* 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)); migrate_add_blocker(s->migration_blocker); 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); 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; } static int qcow_set_key(BlockDriverState *bs, const char *key) { BDRVQcowState *s = bs->opaque; uint8_t keybuf[16]; int len, i; Error *err; memset(keybuf, 0, 16); len = strlen(key); if (len > 16) len = 16; /* XXX: we could compress the chars to 7 bits to increase entropy */ for(i = 0;i < len;i++) { keybuf[i] = key[i]; } assert(bs->encrypted); qcrypto_cipher_free(s->cipher); s->cipher = qcrypto_cipher_new( QCRYPTO_CIPHER_ALG_AES_128, QCRYPTO_CIPHER_MODE_CBC, keybuf, G_N_ELEMENTS(keybuf), &err); if (!s->cipher) { /* XXX would be nice if errors in this method could * be properly propagate to the caller. Would need * the bdrv_set_key() API signature to be fixed. */ error_free(err); return -1; } return 0; } /* The crypt function is compatible with the linux cryptoloop algorithm for < 4 GB images. NOTE: out_buf == in_buf is supported */ static int encrypt_sectors(BDRVQcowState *s, int64_t sector_num, uint8_t *out_buf, const uint8_t *in_buf, int nb_sectors, bool enc, Error **errp) { union { uint64_t ll[2]; uint8_t b[16]; } ivec; int i; int ret; for(i = 0; i < nb_sectors; i++) { ivec.ll[0] = cpu_to_le64(sector_num); ivec.ll[1] = 0; if (qcrypto_cipher_setiv(s->cipher, ivec.b, G_N_ELEMENTS(ivec.b), errp) < 0) { return -1; } if (enc) { ret = qcrypto_cipher_encrypt(s->cipher, in_buf, out_buf, 512, errp); } else { ret = qcrypto_cipher_decrypt(s->cipher, in_buf, out_buf, 512, errp); } if (ret < 0) { return -1; } sector_num++; in_buf += 512; out_buf += 512; } return 0; } /* 'allocate' is: * * 0 to not allocate. * * 1 to allocate a normal cluster (for sector indexes 'n_start' to * 'n_end') * * 2 to allocate a compressed cluster of size * 'compressed_size'. 'compressed_size' must be > 0 and < * cluster_size * * return 0 if not allocated. */ static uint64_t get_cluster_offset(BlockDriverState *bs, uint64_t offset, int allocate, int compressed_size, int n_start, int n_end) { BDRVQcowState *s = bs->opaque; int min_index, i, j, l1_index, l2_index; uint64_t l2_offset, *l2_table, cluster_offset, tmp; uint32_t min_count; int new_l2_table; 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); /* round to cluster size */ l2_offset = (l2_offset + s->cluster_size - 1) & ~(s->cluster_size - 1); /* update the L1 entry */ s->l1_table[l1_index] = l2_offset; tmp = cpu_to_be64(l2_offset); if (bdrv_pwrite_sync(bs->file->bs, s->l1_table_offset + l1_index * sizeof(tmp), &tmp, sizeof(tmp)) < 0) return 0; 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); if (new_l2_table) { memset(l2_table, 0, s->l2_size * sizeof(uint64_t)); if (bdrv_pwrite_sync(bs->file->bs, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) < 0) return 0; } else { if (bdrv_pread(bs->file->bs, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) != s->l2_size * sizeof(uint64_t)) return 0; } 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; /* allocate a new cluster */ if ((cluster_offset & QCOW_OFLAG_COMPRESSED) && (n_end - n_start) < s->cluster_sectors) { /* 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 0; cluster_offset = bdrv_getlength(bs->file->bs); cluster_offset = (cluster_offset + s->cluster_size - 1) & ~(s->cluster_size - 1); /* write the cluster content */ if (bdrv_pwrite(bs->file->bs, cluster_offset, s->cluster_cache, s->cluster_size) != s->cluster_size) return -1; } else { cluster_offset = bdrv_getlength(bs->file->bs); if (allocate == 1) { /* round to cluster size */ cluster_offset = (cluster_offset + s->cluster_size - 1) & ~(s->cluster_size - 1); bdrv_truncate(bs->file->bs, cluster_offset + s->cluster_size); /* if encrypted, we must initialize the cluster content which won't be written */ if (bs->encrypted && (n_end - n_start) < s->cluster_sectors) { uint64_t start_sect; assert(s->cipher); start_sect = (offset & ~(s->cluster_size - 1)) >> 9; memset(s->cluster_data + 512, 0x00, 512); for(i = 0; i < s->cluster_sectors; i++) { if (i < n_start || i >= n_end) { Error *err = NULL; if (encrypt_sectors(s, start_sect + i, s->cluster_data, s->cluster_data + 512, 1, true, &err) < 0) { error_free(err); errno = EIO; return -1; } if (bdrv_pwrite(bs->file->bs, cluster_offset + i * 512, s->cluster_data, 512) != 512) return -1; } } } } 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 (bdrv_pwrite_sync(bs->file->bs, l2_offset + l2_index * sizeof(tmp), &tmp, sizeof(tmp)) < 0) return 0; } return cluster_offset; } static int64_t coroutine_fn qcow_co_get_block_status(BlockDriverState *bs, int64_t sector_num, int nb_sectors, int *pnum, BlockDriverState **file) { BDRVQcowState *s = bs->opaque; int index_in_cluster, n; uint64_t cluster_offset; qemu_co_mutex_lock(&s->lock); cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0); qemu_co_mutex_unlock(&s->lock); index_in_cluster = sector_num & (s->cluster_sectors - 1); n = s->cluster_sectors - index_in_cluster; if (n > nb_sectors) n = nb_sectors; *pnum = n; if (!cluster_offset) { return 0; } if ((cluster_offset & QCOW_OFLAG_COMPRESSED) || s->cipher) { return BDRV_BLOCK_DATA; } cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS); *file = bs->file->bs; return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | cluster_offset; } 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); ret = bdrv_pread(bs->file->bs, coffset, s->cluster_data, csize); if (ret != csize) 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 coroutine_fn int qcow_co_readv(BlockDriverState *bs, int64_t sector_num, int nb_sectors, QEMUIOVector *qiov) { BDRVQcowState *s = bs->opaque; int index_in_cluster; int ret = 0, n; uint64_t cluster_offset; struct iovec hd_iov; QEMUIOVector hd_qiov; uint8_t *buf; void *orig_buf; Error *err = NULL; 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 (nb_sectors != 0) { /* prepare next request */ cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0); index_in_cluster = sector_num & (s->cluster_sectors - 1); n = s->cluster_sectors - index_in_cluster; if (n > nb_sectors) { n = nb_sectors; } if (!cluster_offset) { if (bs->backing) { /* read from the base image */ hd_iov.iov_base = (void *)buf; hd_iov.iov_len = n * 512; qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); qemu_co_mutex_unlock(&s->lock); ret = bdrv_co_readv(bs->backing->bs, sector_num, n, &hd_qiov); qemu_co_mutex_lock(&s->lock); if (ret < 0) { goto fail; } } else { /* Note: in this case, no need to wait */ memset(buf, 0, 512 * n); } } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) { /* add AIO support for compressed blocks ? */ if (decompress_cluster(bs, cluster_offset) < 0) { goto fail; } memcpy(buf, s->cluster_cache + index_in_cluster * 512, 512 * n); } else { if ((cluster_offset & 511) != 0) { goto fail; } hd_iov.iov_base = (void *)buf; hd_iov.iov_len = n * 512; qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); qemu_co_mutex_unlock(&s->lock); ret = bdrv_co_readv(bs->file->bs, (cluster_offset >> 9) + index_in_cluster, n, &hd_qiov); qemu_co_mutex_lock(&s->lock); if (ret < 0) { break; } if (bs->encrypted) { assert(s->cipher); if (encrypt_sectors(s, sector_num, buf, buf, n, false, &err) < 0) { goto fail; } } } ret = 0; nb_sectors -= n; sector_num += n; buf += n * 512; } done: 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; fail: error_free(err); ret = -EIO; goto done; } static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num, int nb_sectors, QEMUIOVector *qiov) { BDRVQcowState *s = bs->opaque; int index_in_cluster; uint64_t cluster_offset; const uint8_t *src_buf; int ret = 0, n; uint8_t *cluster_data = NULL; struct iovec hd_iov; QEMUIOVector hd_qiov; uint8_t *buf; void *orig_buf; s->cluster_cache_offset = -1; /* disable compressed cache */ if (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 (nb_sectors != 0) { index_in_cluster = sector_num & (s->cluster_sectors - 1); n = s->cluster_sectors - index_in_cluster; if (n > nb_sectors) { n = nb_sectors; } cluster_offset = get_cluster_offset(bs, sector_num << 9, 1, 0, index_in_cluster, index_in_cluster + n); if (!cluster_offset || (cluster_offset & 511) != 0) { ret = -EIO; break; } if (bs->encrypted) { Error *err = NULL; assert(s->cipher); if (!cluster_data) { cluster_data = g_malloc0(s->cluster_size); } if (encrypt_sectors(s, sector_num, cluster_data, buf, n, true, &err) < 0) { error_free(err); ret = -EIO; break; } src_buf = cluster_data; } else { src_buf = buf; } hd_iov.iov_base = (void *)src_buf; hd_iov.iov_len = n * 512; qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); qemu_co_mutex_unlock(&s->lock); ret = bdrv_co_writev(bs->file->bs, (cluster_offset >> 9) + index_in_cluster, n, &hd_qiov); qemu_co_mutex_lock(&s->lock); if (ret < 0) { break; } ret = 0; nb_sectors -= n; sector_num += n; buf += n * 512; } qemu_co_mutex_unlock(&s->lock); if (qiov->niov > 1) { qemu_vfree(orig_buf); } g_free(cluster_data); return ret; } static void qcow_close(BlockDriverState *bs) { BDRVQcowState *s = bs->opaque; qcrypto_cipher_free(s->cipher); s->cipher = 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 qcow_create(const char *filename, QemuOpts *opts, Error **errp) { int header_size, backing_filename_len, l1_size, shift, i; QCowHeader header; uint8_t *tmp; int64_t total_size = 0; char *backing_file = NULL; int flags = 0; Error *local_err = NULL; int ret; BlockBackend *qcow_blk; /* Read out options */ total_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0), BDRV_SECTOR_SIZE); backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) { flags |= BLOCK_FLAG_ENCRYPT; } ret = bdrv_create_file(filename, opts, &local_err); if (ret < 0) { error_propagate(errp, local_err); goto cleanup; } qcow_blk = blk_new_open("image", filename, NULL, NULL, BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_PROTOCOL, &local_err); if (qcow_blk == NULL) { error_propagate(errp, local_err); ret = -EIO; goto cleanup; } blk_set_allow_write_beyond_eof(qcow_blk, true); ret = blk_truncate(qcow_blk, 0); if (ret < 0) { goto exit; } 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 (backing_file) { if (strcmp(backing_file, "fat:")) { header.backing_file_offset = cpu_to_be64(header_size); backing_filename_len = strlen(backing_file); header.backing_file_size = cpu_to_be32(backing_filename_len); header_size += backing_filename_len; } else { /* special backing file for vvfat */ backing_file = NULL; } 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 (flags & BLOCK_FLAG_ENCRYPT) { header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES); } else { header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); } /* write all the data */ ret = blk_pwrite(qcow_blk, 0, &header, sizeof(header)); if (ret != sizeof(header)) { goto exit; } if (backing_file) { ret = blk_pwrite(qcow_blk, sizeof(header), backing_file, backing_filename_len); if (ret != backing_filename_len) { goto exit; } } tmp = g_malloc0(BDRV_SECTOR_SIZE); for (i = 0; i < ((sizeof(uint64_t)*l1_size + BDRV_SECTOR_SIZE - 1)/ BDRV_SECTOR_SIZE); i++) { ret = blk_pwrite(qcow_blk, header_size + BDRV_SECTOR_SIZE*i, tmp, BDRV_SECTOR_SIZE); if (ret != BDRV_SECTOR_SIZE) { g_free(tmp); goto exit; } } g_free(tmp); ret = 0; exit: blk_unref(qcow_blk); cleanup: g_free(backing_file); 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->bs, s->l1_table_offset, s->l1_table, l1_length) < 0) return -1; ret = bdrv_truncate(bs->file->bs, s->l1_table_offset + l1_length); 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 int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num, const uint8_t *buf, int nb_sectors) { BDRVQcowState *s = bs->opaque; z_stream strm; int ret, out_len; uint8_t *out_buf; uint64_t cluster_offset; if (nb_sectors != s->cluster_sectors) { ret = -EINVAL; /* Zero-pad last write if image size is not cluster aligned */ if (sector_num + nb_sectors == bs->total_sectors && nb_sectors < s->cluster_sectors) { uint8_t *pad_buf = qemu_blockalign(bs, s->cluster_size); memset(pad_buf, 0, s->cluster_size); memcpy(pad_buf, buf, nb_sectors * BDRV_SECTOR_SIZE); ret = qcow_write_compressed(bs, sector_num, pad_buf, s->cluster_sectors); qemu_vfree(pad_buf); } return ret; } out_buf = g_malloc(s->cluster_size + (s->cluster_size / 1000) + 128); /* 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 = bdrv_write(bs, sector_num, buf, s->cluster_sectors); if (ret < 0) { goto fail; } } else { cluster_offset = get_cluster_offset(bs, sector_num << 9, 2, out_len, 0, 0); if (cluster_offset == 0) { ret = -EIO; goto fail; } cluster_offset &= s->cluster_offset_mask; ret = bdrv_pwrite(bs->file->bs, cluster_offset, out_buf, out_len); if (ret < 0) { goto fail; } } ret = 0; fail: 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_ENCRYPT, .type = QEMU_OPT_BOOL, .help = "Encrypt the image", .def_value_str = "off" }, { /* end of list */ } } }; static BlockDriver bdrv_qcow = { .format_name = "qcow", .instance_size = sizeof(BDRVQcowState), .bdrv_probe = qcow_probe, .bdrv_open = qcow_open, .bdrv_close = qcow_close, .bdrv_reopen_prepare = qcow_reopen_prepare, .bdrv_create = qcow_create, .bdrv_has_zero_init = bdrv_has_zero_init_1, .supports_backing = true, .bdrv_co_readv = qcow_co_readv, .bdrv_co_writev = qcow_co_writev, .bdrv_co_get_block_status = qcow_co_get_block_status, .bdrv_set_key = qcow_set_key, .bdrv_make_empty = qcow_make_empty, .bdrv_write_compressed = qcow_write_compressed, .bdrv_get_info = qcow_get_info, .create_opts = &qcow_create_opts, }; static void bdrv_qcow_init(void) { bdrv_register(&bdrv_qcow); } block_init(bdrv_qcow_init);