diff options
Diffstat (limited to 'src/block/qcow.c')
| -rw-r--r-- | src/block/qcow.c | 1039 |
1 files changed, 1039 insertions, 0 deletions
diff --git a/src/block/qcow.c b/src/block/qcow.c new file mode 100644 index 0000000..635085e --- /dev/null +++ b/src/block/qcow.c @@ -0,0 +1,1039 @@ +/* + * 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-common.h" +#include "block/block_int.h" +#include "qemu/module.h" +#include <zlib.h> +#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) +{ + 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); + 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; + BlockDriverState *qcow_bs; + + /* 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_bs = NULL; + ret = bdrv_open(&qcow_bs, filename, NULL, NULL, + BDRV_O_RDWR | BDRV_O_PROTOCOL, &local_err); + if (ret < 0) { + error_propagate(errp, local_err); + goto cleanup; + } + + ret = bdrv_truncate(qcow_bs, 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 = bdrv_pwrite(qcow_bs, 0, &header, sizeof(header)); + if (ret != sizeof(header)) { + goto exit; + } + + if (backing_file) { + ret = bdrv_pwrite(qcow_bs, 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 = bdrv_pwrite(qcow_bs, 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: + bdrv_unref(qcow_bs); +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); |
