| /* |
| * Block driver for the QCOW version 2 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_int.h" |
| #include "module.h" |
| #include <zlib.h> |
| #include "aes.h" |
| #include "block/qcow2.h" |
| #include "qemu-error.h" |
| #include "qerror.h" |
| |
| /* |
| Differences with QCOW: |
| |
| - Support for multiple incremental snapshots. |
| - Memory management by reference counts. |
| - Clusters which have a reference count of one have the bit |
| QCOW_OFLAG_COPIED to optimize write performance. |
| - Size of compressed clusters is stored in sectors to reduce bit usage |
| in the cluster offsets. |
| - Support for storing additional data (such as the VM state) in the |
| snapshots. |
| - If a backing store is used, the cluster size is not constrained |
| (could be backported to QCOW). |
| - L2 tables have always a size of one cluster. |
| */ |
| |
| |
| typedef struct { |
| uint32_t magic; |
| uint32_t len; |
| } QCowExtension; |
| #define QCOW2_EXT_MAGIC_END 0 |
| #define QCOW2_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA |
| |
| static int qcow2_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; |
| } |
| |
| |
| /* |
| * read qcow2 extension and fill bs |
| * start reading from start_offset |
| * finish reading upon magic of value 0 or when end_offset reached |
| * unknown magic is skipped (future extension this version knows nothing about) |
| * return 0 upon success, non-0 otherwise |
| */ |
| static int qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset, |
| uint64_t end_offset) |
| { |
| QCowExtension ext; |
| uint64_t offset; |
| |
| #ifdef DEBUG_EXT |
| printf("qcow2_read_extensions: start=%ld end=%ld\n", start_offset, end_offset); |
| #endif |
| offset = start_offset; |
| while (offset < end_offset) { |
| |
| #ifdef DEBUG_EXT |
| BDRVQcowState *s = bs->opaque; |
| /* Sanity check */ |
| if (offset > s->cluster_size) |
| printf("qcow2_read_extension: suspicious offset %lu\n", offset); |
| |
| printf("attemting to read extended header in offset %lu\n", offset); |
| #endif |
| |
| if (bdrv_pread(bs->file, offset, &ext, sizeof(ext)) != sizeof(ext)) { |
| fprintf(stderr, "qcow2_read_extension: ERROR: " |
| "pread fail from offset %" PRIu64 "\n", |
| offset); |
| return 1; |
| } |
| be32_to_cpus(&ext.magic); |
| be32_to_cpus(&ext.len); |
| offset += sizeof(ext); |
| #ifdef DEBUG_EXT |
| printf("ext.magic = 0x%x\n", ext.magic); |
| #endif |
| switch (ext.magic) { |
| case QCOW2_EXT_MAGIC_END: |
| return 0; |
| |
| case QCOW2_EXT_MAGIC_BACKING_FORMAT: |
| if (ext.len >= sizeof(bs->backing_format)) { |
| fprintf(stderr, "ERROR: ext_backing_format: len=%u too large" |
| " (>=%zu)\n", |
| ext.len, sizeof(bs->backing_format)); |
| return 2; |
| } |
| if (bdrv_pread(bs->file, offset , bs->backing_format, |
| ext.len) != ext.len) |
| return 3; |
| bs->backing_format[ext.len] = '\0'; |
| #ifdef DEBUG_EXT |
| printf("Qcow2: Got format extension %s\n", bs->backing_format); |
| #endif |
| offset = ((offset + ext.len + 7) & ~7); |
| break; |
| |
| default: |
| /* unknown magic -- just skip it */ |
| offset = ((offset + ext.len + 7) & ~7); |
| break; |
| } |
| } |
| |
| return 0; |
| } |
| |
| |
| static int qcow2_open(BlockDriverState *bs, int flags) |
| { |
| BDRVQcowState *s = bs->opaque; |
| int len, i, ret = 0; |
| QCowHeader header; |
| uint64_t ext_end; |
| bool writethrough; |
| |
| ret = bdrv_pread(bs->file, 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); |
| be64_to_cpus(&header.size); |
| be32_to_cpus(&header.cluster_bits); |
| be32_to_cpus(&header.crypt_method); |
| be64_to_cpus(&header.l1_table_offset); |
| be32_to_cpus(&header.l1_size); |
| be64_to_cpus(&header.refcount_table_offset); |
| be32_to_cpus(&header.refcount_table_clusters); |
| be64_to_cpus(&header.snapshots_offset); |
| be32_to_cpus(&header.nb_snapshots); |
| |
| if (header.magic != QCOW_MAGIC) { |
| ret = -EINVAL; |
| goto fail; |
| } |
| if (header.version != QCOW_VERSION) { |
| char version[64]; |
| snprintf(version, sizeof(version), "QCOW version %d", header.version); |
| qerror_report(QERR_UNKNOWN_BLOCK_FORMAT_FEATURE, |
| bs->device_name, "qcow2", version); |
| ret = -ENOTSUP; |
| goto fail; |
| } |
| if (header.cluster_bits < MIN_CLUSTER_BITS || |
| header.cluster_bits > MAX_CLUSTER_BITS) { |
| ret = -EINVAL; |
| goto fail; |
| } |
| if (header.crypt_method > QCOW_CRYPT_AES) { |
| 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 = s->cluster_bits - 3; /* L2 is always one cluster */ |
| s->l2_size = 1 << s->l2_bits; |
| bs->total_sectors = header.size / 512; |
| s->csize_shift = (62 - (s->cluster_bits - 8)); |
| s->csize_mask = (1 << (s->cluster_bits - 8)) - 1; |
| s->cluster_offset_mask = (1LL << s->csize_shift) - 1; |
| s->refcount_table_offset = header.refcount_table_offset; |
| s->refcount_table_size = |
| header.refcount_table_clusters << (s->cluster_bits - 3); |
| |
| s->snapshots_offset = header.snapshots_offset; |
| s->nb_snapshots = header.nb_snapshots; |
| |
| /* read the level 1 table */ |
| s->l1_size = header.l1_size; |
| s->l1_vm_state_index = size_to_l1(s, header.size); |
| /* the L1 table must contain at least enough entries to put |
| header.size bytes */ |
| if (s->l1_size < s->l1_vm_state_index) { |
| ret = -EINVAL; |
| goto fail; |
| } |
| s->l1_table_offset = header.l1_table_offset; |
| if (s->l1_size > 0) { |
| s->l1_table = g_malloc0( |
| align_offset(s->l1_size * sizeof(uint64_t), 512)); |
| ret = bdrv_pread(bs->file, 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 table/refcount block cache */ |
| writethrough = ((flags & BDRV_O_CACHE_WB) == 0); |
| s->l2_table_cache = qcow2_cache_create(bs, L2_CACHE_SIZE, writethrough); |
| s->refcount_block_cache = qcow2_cache_create(bs, REFCOUNT_CACHE_SIZE, |
| writethrough); |
| |
| s->cluster_cache = g_malloc(s->cluster_size); |
| /* one more sector for decompressed data alignment */ |
| s->cluster_data = qemu_blockalign(bs, QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size |
| + 512); |
| s->cluster_cache_offset = -1; |
| |
| ret = qcow2_refcount_init(bs); |
| if (ret != 0) { |
| goto fail; |
| } |
| |
| QLIST_INIT(&s->cluster_allocs); |
| |
| /* read qcow2 extensions */ |
| if (header.backing_file_offset) { |
| ext_end = header.backing_file_offset; |
| } else { |
| ext_end = s->cluster_size; |
| } |
| if (qcow2_read_extensions(bs, sizeof(header), ext_end)) { |
| ret = -EINVAL; |
| goto fail; |
| } |
| |
| /* read the backing file name */ |
| if (header.backing_file_offset != 0) { |
| len = header.backing_file_size; |
| if (len > 1023) { |
| len = 1023; |
| } |
| ret = bdrv_pread(bs->file, header.backing_file_offset, |
| bs->backing_file, len); |
| if (ret < 0) { |
| goto fail; |
| } |
| bs->backing_file[len] = '\0'; |
| } |
| if (qcow2_read_snapshots(bs) < 0) { |
| ret = -EINVAL; |
| goto fail; |
| } |
| |
| /* Initialise locks */ |
| qemu_co_mutex_init(&s->lock); |
| |
| #ifdef DEBUG_ALLOC |
| { |
| BdrvCheckResult result = {0}; |
| qcow2_check_refcounts(bs, &result); |
| } |
| #endif |
| return ret; |
| |
| fail: |
| qcow2_free_snapshots(bs); |
| qcow2_refcount_close(bs); |
| g_free(s->l1_table); |
| if (s->l2_table_cache) { |
| qcow2_cache_destroy(bs, s->l2_table_cache); |
| } |
| g_free(s->cluster_cache); |
| qemu_vfree(s->cluster_data); |
| return ret; |
| } |
| |
| static int qcow2_set_key(BlockDriverState *bs, const char *key) |
| { |
| BDRVQcowState *s = bs->opaque; |
| uint8_t keybuf[16]; |
| int len, i; |
| |
| 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]; |
| } |
| s->crypt_method = s->crypt_method_header; |
| |
| if (AES_set_encrypt_key(keybuf, 128, &s->aes_encrypt_key) != 0) |
| return -1; |
| if (AES_set_decrypt_key(keybuf, 128, &s->aes_decrypt_key) != 0) |
| return -1; |
| #if 0 |
| /* test */ |
| { |
| uint8_t in[16]; |
| uint8_t out[16]; |
| uint8_t tmp[16]; |
| for(i=0;i<16;i++) |
| in[i] = i; |
| AES_encrypt(in, tmp, &s->aes_encrypt_key); |
| AES_decrypt(tmp, out, &s->aes_decrypt_key); |
| for(i = 0; i < 16; i++) |
| printf(" %02x", tmp[i]); |
| printf("\n"); |
| for(i = 0; i < 16; i++) |
| printf(" %02x", out[i]); |
| printf("\n"); |
| } |
| #endif |
| return 0; |
| } |
| |
| static int qcow2_is_allocated(BlockDriverState *bs, int64_t sector_num, |
| int nb_sectors, int *pnum) |
| { |
| uint64_t cluster_offset; |
| int ret; |
| |
| *pnum = nb_sectors; |
| /* FIXME We can get errors here, but the bdrv_is_allocated interface can't |
| * pass them on today */ |
| ret = qcow2_get_cluster_offset(bs, sector_num << 9, pnum, &cluster_offset); |
| if (ret < 0) { |
| *pnum = 0; |
| } |
| |
| return (cluster_offset != 0); |
| } |
| |
| /* handle reading after the end of the backing file */ |
| int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov, |
| int64_t sector_num, int nb_sectors) |
| { |
| int n1; |
| if ((sector_num + nb_sectors) <= bs->total_sectors) |
| return nb_sectors; |
| if (sector_num >= bs->total_sectors) |
| n1 = 0; |
| else |
| n1 = bs->total_sectors - sector_num; |
| |
| qemu_iovec_memset_skip(qiov, 0, 512 * (nb_sectors - n1), 512 * n1); |
| |
| return n1; |
| } |
| |
| static int qcow2_co_readv(BlockDriverState *bs, int64_t sector_num, |
| int remaining_sectors, QEMUIOVector *qiov) |
| { |
| BDRVQcowState *s = bs->opaque; |
| int index_in_cluster, n1; |
| int ret; |
| int cur_nr_sectors; /* number of sectors in current iteration */ |
| uint64_t cluster_offset = 0; |
| uint64_t bytes_done = 0; |
| QEMUIOVector hd_qiov; |
| uint8_t *cluster_data = NULL; |
| |
| qemu_iovec_init(&hd_qiov, qiov->niov); |
| |
| qemu_co_mutex_lock(&s->lock); |
| |
| while (remaining_sectors != 0) { |
| |
| /* prepare next request */ |
| cur_nr_sectors = remaining_sectors; |
| if (s->crypt_method) { |
| cur_nr_sectors = MIN(cur_nr_sectors, |
| QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors); |
| } |
| |
| ret = qcow2_get_cluster_offset(bs, sector_num << 9, |
| &cur_nr_sectors, &cluster_offset); |
| if (ret < 0) { |
| goto fail; |
| } |
| |
| index_in_cluster = sector_num & (s->cluster_sectors - 1); |
| |
| qemu_iovec_reset(&hd_qiov); |
| qemu_iovec_copy(&hd_qiov, qiov, bytes_done, |
| cur_nr_sectors * 512); |
| |
| if (!cluster_offset) { |
| |
| if (bs->backing_hd) { |
| /* read from the base image */ |
| n1 = qcow2_backing_read1(bs->backing_hd, &hd_qiov, |
| sector_num, cur_nr_sectors); |
| if (n1 > 0) { |
| BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO); |
| qemu_co_mutex_unlock(&s->lock); |
| ret = bdrv_co_readv(bs->backing_hd, sector_num, |
| n1, &hd_qiov); |
| qemu_co_mutex_lock(&s->lock); |
| if (ret < 0) { |
| goto fail; |
| } |
| } |
| } else { |
| /* Note: in this case, no need to wait */ |
| qemu_iovec_memset(&hd_qiov, 0, 512 * cur_nr_sectors); |
| } |
| } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) { |
| /* add AIO support for compressed blocks ? */ |
| ret = qcow2_decompress_cluster(bs, cluster_offset); |
| if (ret < 0) { |
| goto fail; |
| } |
| |
| qemu_iovec_from_buffer(&hd_qiov, |
| s->cluster_cache + index_in_cluster * 512, |
| 512 * cur_nr_sectors); |
| } else { |
| if ((cluster_offset & 511) != 0) { |
| ret = -EIO; |
| goto fail; |
| } |
| |
| if (s->crypt_method) { |
| /* |
| * For encrypted images, read everything into a temporary |
| * contiguous buffer on which the AES functions can work. |
| */ |
| if (!cluster_data) { |
| cluster_data = |
| qemu_blockalign(bs, QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); |
| } |
| |
| assert(cur_nr_sectors <= |
| QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors); |
| qemu_iovec_reset(&hd_qiov); |
| qemu_iovec_add(&hd_qiov, cluster_data, |
| 512 * cur_nr_sectors); |
| } |
| |
| BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); |
| qemu_co_mutex_unlock(&s->lock); |
| ret = bdrv_co_readv(bs->file, |
| (cluster_offset >> 9) + index_in_cluster, |
| cur_nr_sectors, &hd_qiov); |
| qemu_co_mutex_lock(&s->lock); |
| if (ret < 0) { |
| goto fail; |
| } |
| if (s->crypt_method) { |
| qcow2_encrypt_sectors(s, sector_num, cluster_data, |
| cluster_data, cur_nr_sectors, 0, &s->aes_decrypt_key); |
| qemu_iovec_reset(&hd_qiov); |
| qemu_iovec_copy(&hd_qiov, qiov, bytes_done, |
| cur_nr_sectors * 512); |
| qemu_iovec_from_buffer(&hd_qiov, cluster_data, |
| 512 * cur_nr_sectors); |
| } |
| } |
| |
| remaining_sectors -= cur_nr_sectors; |
| sector_num += cur_nr_sectors; |
| bytes_done += cur_nr_sectors * 512; |
| } |
| ret = 0; |
| |
| fail: |
| qemu_co_mutex_unlock(&s->lock); |
| |
| qemu_iovec_destroy(&hd_qiov); |
| qemu_vfree(cluster_data); |
| |
| return ret; |
| } |
| |
| static void run_dependent_requests(BDRVQcowState *s, QCowL2Meta *m) |
| { |
| /* Take the request off the list of running requests */ |
| if (m->nb_clusters != 0) { |
| QLIST_REMOVE(m, next_in_flight); |
| } |
| |
| /* Restart all dependent requests */ |
| if (!qemu_co_queue_empty(&m->dependent_requests)) { |
| qemu_co_mutex_unlock(&s->lock); |
| while(qemu_co_queue_next(&m->dependent_requests)); |
| qemu_co_mutex_lock(&s->lock); |
| } |
| } |
| |
| static int qcow2_co_writev(BlockDriverState *bs, |
| int64_t sector_num, |
| int remaining_sectors, |
| QEMUIOVector *qiov) |
| { |
| BDRVQcowState *s = bs->opaque; |
| int index_in_cluster; |
| int n_end; |
| int ret; |
| int cur_nr_sectors; /* number of sectors in current iteration */ |
| uint64_t cluster_offset; |
| QEMUIOVector hd_qiov; |
| uint64_t bytes_done = 0; |
| uint8_t *cluster_data = NULL; |
| QCowL2Meta l2meta = { |
| .nb_clusters = 0, |
| }; |
| |
| qemu_co_queue_init(&l2meta.dependent_requests); |
| |
| qemu_iovec_init(&hd_qiov, qiov->niov); |
| |
| s->cluster_cache_offset = -1; /* disable compressed cache */ |
| |
| qemu_co_mutex_lock(&s->lock); |
| |
| while (remaining_sectors != 0) { |
| |
| index_in_cluster = sector_num & (s->cluster_sectors - 1); |
| n_end = index_in_cluster + remaining_sectors; |
| if (s->crypt_method && |
| n_end > QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors) { |
| n_end = QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors; |
| } |
| |
| ret = qcow2_alloc_cluster_offset(bs, sector_num << 9, |
| index_in_cluster, n_end, &cur_nr_sectors, &l2meta); |
| if (ret < 0) { |
| goto fail; |
| } |
| |
| cluster_offset = l2meta.cluster_offset; |
| assert((cluster_offset & 511) == 0); |
| |
| qemu_iovec_reset(&hd_qiov); |
| qemu_iovec_copy(&hd_qiov, qiov, bytes_done, |
| cur_nr_sectors * 512); |
| |
| if (s->crypt_method) { |
| if (!cluster_data) { |
| cluster_data = qemu_blockalign(bs, QCOW_MAX_CRYPT_CLUSTERS * |
| s->cluster_size); |
| } |
| |
| assert(hd_qiov.size <= |
| QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); |
| qemu_iovec_to_buffer(&hd_qiov, cluster_data); |
| |
| qcow2_encrypt_sectors(s, sector_num, cluster_data, |
| cluster_data, cur_nr_sectors, 1, &s->aes_encrypt_key); |
| |
| qemu_iovec_reset(&hd_qiov); |
| qemu_iovec_add(&hd_qiov, cluster_data, |
| cur_nr_sectors * 512); |
| } |
| |
| BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); |
| qemu_co_mutex_unlock(&s->lock); |
| ret = bdrv_co_writev(bs->file, |
| (cluster_offset >> 9) + index_in_cluster, |
| cur_nr_sectors, &hd_qiov); |
| qemu_co_mutex_lock(&s->lock); |
| if (ret < 0) { |
| goto fail; |
| } |
| |
| ret = qcow2_alloc_cluster_link_l2(bs, &l2meta); |
| if (ret < 0) { |
| goto fail; |
| } |
| |
| run_dependent_requests(s, &l2meta); |
| |
| remaining_sectors -= cur_nr_sectors; |
| sector_num += cur_nr_sectors; |
| bytes_done += cur_nr_sectors * 512; |
| } |
| ret = 0; |
| |
| fail: |
| run_dependent_requests(s, &l2meta); |
| |
| qemu_co_mutex_unlock(&s->lock); |
| |
| qemu_iovec_destroy(&hd_qiov); |
| qemu_vfree(cluster_data); |
| |
| return ret; |
| } |
| |
| static void qcow2_close(BlockDriverState *bs) |
| { |
| BDRVQcowState *s = bs->opaque; |
| g_free(s->l1_table); |
| |
| qcow2_cache_flush(bs, s->l2_table_cache); |
| qcow2_cache_flush(bs, s->refcount_block_cache); |
| |
| qcow2_cache_destroy(bs, s->l2_table_cache); |
| qcow2_cache_destroy(bs, s->refcount_block_cache); |
| |
| g_free(s->cluster_cache); |
| qemu_vfree(s->cluster_data); |
| qcow2_refcount_close(bs); |
| } |
| |
| /* |
| * Updates the variable length parts of the qcow2 header, i.e. the backing file |
| * name and all extensions. qcow2 was not designed to allow such changes, so if |
| * we run out of space (we can only use the first cluster) this function may |
| * fail. |
| * |
| * Returns 0 on success, -errno in error cases. |
| */ |
| static int qcow2_update_ext_header(BlockDriverState *bs, |
| const char *backing_file, const char *backing_fmt) |
| { |
| size_t backing_file_len = 0; |
| size_t backing_fmt_len = 0; |
| BDRVQcowState *s = bs->opaque; |
| QCowExtension ext_backing_fmt = {0, 0}; |
| int ret; |
| |
| /* Backing file format doesn't make sense without a backing file */ |
| if (backing_fmt && !backing_file) { |
| return -EINVAL; |
| } |
| |
| /* Prepare the backing file format extension if needed */ |
| if (backing_fmt) { |
| ext_backing_fmt.len = cpu_to_be32(strlen(backing_fmt)); |
| ext_backing_fmt.magic = cpu_to_be32(QCOW2_EXT_MAGIC_BACKING_FORMAT); |
| backing_fmt_len = ((sizeof(ext_backing_fmt) |
| + strlen(backing_fmt) + 7) & ~7); |
| } |
| |
| /* Check if we can fit the new header into the first cluster */ |
| if (backing_file) { |
| backing_file_len = strlen(backing_file); |
| } |
| |
| size_t header_size = sizeof(QCowHeader) + backing_file_len |
| + backing_fmt_len; |
| |
| if (header_size > s->cluster_size) { |
| return -ENOSPC; |
| } |
| |
| /* Rewrite backing file name and qcow2 extensions */ |
| size_t ext_size = header_size - sizeof(QCowHeader); |
| uint8_t buf[ext_size]; |
| size_t offset = 0; |
| size_t backing_file_offset = 0; |
| |
| if (backing_file) { |
| if (backing_fmt) { |
| int padding = backing_fmt_len - |
| (sizeof(ext_backing_fmt) + strlen(backing_fmt)); |
| |
| memcpy(buf + offset, &ext_backing_fmt, sizeof(ext_backing_fmt)); |
| offset += sizeof(ext_backing_fmt); |
| |
| memcpy(buf + offset, backing_fmt, strlen(backing_fmt)); |
| offset += strlen(backing_fmt); |
| |
| memset(buf + offset, 0, padding); |
| offset += padding; |
| } |
| |
| memcpy(buf + offset, backing_file, backing_file_len); |
| backing_file_offset = sizeof(QCowHeader) + offset; |
| } |
| |
| ret = bdrv_pwrite_sync(bs->file, sizeof(QCowHeader), buf, ext_size); |
| if (ret < 0) { |
| goto fail; |
| } |
| |
| /* Update header fields */ |
| uint64_t be_backing_file_offset = cpu_to_be64(backing_file_offset); |
| uint32_t be_backing_file_size = cpu_to_be32(backing_file_len); |
| |
| ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, backing_file_offset), |
| &be_backing_file_offset, sizeof(uint64_t)); |
| if (ret < 0) { |
| goto fail; |
| } |
| |
| ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, backing_file_size), |
| &be_backing_file_size, sizeof(uint32_t)); |
| if (ret < 0) { |
| goto fail; |
| } |
| |
| ret = 0; |
| fail: |
| return ret; |
| } |
| |
| static int qcow2_change_backing_file(BlockDriverState *bs, |
| const char *backing_file, const char *backing_fmt) |
| { |
| return qcow2_update_ext_header(bs, backing_file, backing_fmt); |
| } |
| |
| static int preallocate(BlockDriverState *bs) |
| { |
| uint64_t nb_sectors; |
| uint64_t offset; |
| int num; |
| int ret; |
| QCowL2Meta meta; |
| |
| nb_sectors = bdrv_getlength(bs) >> 9; |
| offset = 0; |
| qemu_co_queue_init(&meta.dependent_requests); |
| meta.cluster_offset = 0; |
| |
| while (nb_sectors) { |
| num = MIN(nb_sectors, INT_MAX >> 9); |
| ret = qcow2_alloc_cluster_offset(bs, offset, 0, num, &num, &meta); |
| if (ret < 0) { |
| return ret; |
| } |
| |
| ret = qcow2_alloc_cluster_link_l2(bs, &meta); |
| if (ret < 0) { |
| qcow2_free_any_clusters(bs, meta.cluster_offset, meta.nb_clusters); |
| return ret; |
| } |
| |
| /* There are no dependent requests, but we need to remove our request |
| * from the list of in-flight requests */ |
| run_dependent_requests(bs->opaque, &meta); |
| |
| /* TODO Preallocate data if requested */ |
| |
| nb_sectors -= num; |
| offset += num << 9; |
| } |
| |
| /* |
| * It is expected that the image file is large enough to actually contain |
| * all of the allocated clusters (otherwise we get failing reads after |
| * EOF). Extend the image to the last allocated sector. |
| */ |
| if (meta.cluster_offset != 0) { |
| uint8_t buf[512]; |
| memset(buf, 0, 512); |
| ret = bdrv_write(bs->file, (meta.cluster_offset >> 9) + num - 1, buf, 1); |
| if (ret < 0) { |
| return ret; |
| } |
| } |
| |
| return 0; |
| } |
| |
| static int qcow2_create2(const char *filename, int64_t total_size, |
| const char *backing_file, const char *backing_format, |
| int flags, size_t cluster_size, int prealloc, |
| QEMUOptionParameter *options) |
| { |
| /* Calulate cluster_bits */ |
| int cluster_bits; |
| cluster_bits = ffs(cluster_size) - 1; |
| if (cluster_bits < MIN_CLUSTER_BITS || cluster_bits > MAX_CLUSTER_BITS || |
| (1 << cluster_bits) != cluster_size) |
| { |
| error_report( |
| "Cluster size must be a power of two between %d and %dk", |
| 1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10)); |
| return -EINVAL; |
| } |
| |
| /* |
| * Open the image file and write a minimal qcow2 header. |
| * |
| * We keep things simple and start with a zero-sized image. We also |
| * do without refcount blocks or a L1 table for now. We'll fix the |
| * inconsistency later. |
| * |
| * We do need a refcount table because growing the refcount table means |
| * allocating two new refcount blocks - the seconds of which would be at |
| * 2 GB for 64k clusters, and we don't want to have a 2 GB initial file |
| * size for any qcow2 image. |
| */ |
| BlockDriverState* bs; |
| QCowHeader header; |
| uint8_t* refcount_table; |
| int ret; |
| |
| ret = bdrv_create_file(filename, options); |
| if (ret < 0) { |
| return ret; |
| } |
| |
| ret = bdrv_file_open(&bs, filename, BDRV_O_RDWR); |
| if (ret < 0) { |
| return ret; |
| } |
| |
| /* Write the header */ |
| memset(&header, 0, sizeof(header)); |
| header.magic = cpu_to_be32(QCOW_MAGIC); |
| header.version = cpu_to_be32(QCOW_VERSION); |
| header.cluster_bits = cpu_to_be32(cluster_bits); |
| header.size = cpu_to_be64(0); |
| header.l1_table_offset = cpu_to_be64(0); |
| header.l1_size = cpu_to_be32(0); |
| header.refcount_table_offset = cpu_to_be64(cluster_size); |
| header.refcount_table_clusters = cpu_to_be32(1); |
| |
| if (flags & BLOCK_FLAG_ENCRYPT) { |
| header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES); |
| } else { |
| header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); |
| } |
| |
| ret = bdrv_pwrite(bs, 0, &header, sizeof(header)); |
| if (ret < 0) { |
| goto out; |
| } |
| |
| /* Write an empty refcount table */ |
| refcount_table = g_malloc0(cluster_size); |
| ret = bdrv_pwrite(bs, cluster_size, refcount_table, cluster_size); |
| g_free(refcount_table); |
| |
| if (ret < 0) { |
| goto out; |
| } |
| |
| bdrv_close(bs); |
| |
| /* |
| * And now open the image and make it consistent first (i.e. increase the |
| * refcount of the cluster that is occupied by the header and the refcount |
| * table) |
| */ |
| BlockDriver* drv = bdrv_find_format("qcow2"); |
| assert(drv != NULL); |
| ret = bdrv_open(bs, filename, |
| BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_NO_FLUSH, drv); |
| if (ret < 0) { |
| goto out; |
| } |
| |
| ret = qcow2_alloc_clusters(bs, 2 * cluster_size); |
| if (ret < 0) { |
| goto out; |
| |
| } else if (ret != 0) { |
| error_report("Huh, first cluster in empty image is already in use?"); |
| abort(); |
| } |
| |
| /* Okay, now that we have a valid image, let's give it the right size */ |
| ret = bdrv_truncate(bs, total_size * BDRV_SECTOR_SIZE); |
| if (ret < 0) { |
| goto out; |
| } |
| |
| /* Want a backing file? There you go.*/ |
| if (backing_file) { |
| ret = bdrv_change_backing_file(bs, backing_file, backing_format); |
| if (ret < 0) { |
| goto out; |
| } |
| } |
| |
| /* And if we're supposed to preallocate metadata, do that now */ |
| if (prealloc) { |
| ret = preallocate(bs); |
| if (ret < 0) { |
| goto out; |
| } |
| } |
| |
| ret = 0; |
| out: |
| bdrv_delete(bs); |
| return ret; |
| } |
| |
| static int qcow2_create(const char *filename, QEMUOptionParameter *options) |
| { |
| const char *backing_file = NULL; |
| const char *backing_fmt = NULL; |
| uint64_t sectors = 0; |
| int flags = 0; |
| size_t cluster_size = DEFAULT_CLUSTER_SIZE; |
| int prealloc = 0; |
| |
| /* Read out options */ |
| while (options && options->name) { |
| if (!strcmp(options->name, BLOCK_OPT_SIZE)) { |
| sectors = options->value.n / 512; |
| } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FILE)) { |
| backing_file = options->value.s; |
| } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FMT)) { |
| backing_fmt = options->value.s; |
| } else if (!strcmp(options->name, BLOCK_OPT_ENCRYPT)) { |
| flags |= options->value.n ? BLOCK_FLAG_ENCRYPT : 0; |
| } else if (!strcmp(options->name, BLOCK_OPT_CLUSTER_SIZE)) { |
| if (options->value.n) { |
| cluster_size = options->value.n; |
| } |
| } else if (!strcmp(options->name, BLOCK_OPT_PREALLOC)) { |
| if (!options->value.s || !strcmp(options->value.s, "off")) { |
| prealloc = 0; |
| } else if (!strcmp(options->value.s, "metadata")) { |
| prealloc = 1; |
| } else { |
| fprintf(stderr, "Invalid preallocation mode: '%s'\n", |
| options->value.s); |
| return -EINVAL; |
| } |
| } |
| options++; |
| } |
| |
| if (backing_file && prealloc) { |
| fprintf(stderr, "Backing file and preallocation cannot be used at " |
| "the same time\n"); |
| return -EINVAL; |
| } |
| |
| return qcow2_create2(filename, sectors, backing_file, backing_fmt, flags, |
| cluster_size, prealloc, options); |
| } |
| |
| static int qcow2_make_empty(BlockDriverState *bs) |
| { |
| #if 0 |
| /* XXX: not correct */ |
| 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(bs->file, s->l1_table_offset, s->l1_table, l1_length) < 0) |
| return -1; |
| ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length); |
| if (ret < 0) |
| return ret; |
| |
| l2_cache_reset(bs); |
| #endif |
| return 0; |
| } |
| |
| static coroutine_fn int qcow2_co_discard(BlockDriverState *bs, |
| int64_t sector_num, int nb_sectors) |
| { |
| int ret; |
| BDRVQcowState *s = bs->opaque; |
| |
| qemu_co_mutex_lock(&s->lock); |
| ret = qcow2_discard_clusters(bs, sector_num << BDRV_SECTOR_BITS, |
| nb_sectors); |
| qemu_co_mutex_unlock(&s->lock); |
| return ret; |
| } |
| |
| static int qcow2_truncate(BlockDriverState *bs, int64_t offset) |
| { |
| BDRVQcowState *s = bs->opaque; |
| int ret, new_l1_size; |
| |
| if (offset & 511) { |
| return -EINVAL; |
| } |
| |
| /* cannot proceed if image has snapshots */ |
| if (s->nb_snapshots) { |
| return -ENOTSUP; |
| } |
| |
| /* shrinking is currently not supported */ |
| if (offset < bs->total_sectors * 512) { |
| return -ENOTSUP; |
| } |
| |
| new_l1_size = size_to_l1(s, offset); |
| ret = qcow2_grow_l1_table(bs, new_l1_size, true); |
| if (ret < 0) { |
| return ret; |
| } |
| |
| /* write updated header.size */ |
| offset = cpu_to_be64(offset); |
| ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, size), |
| &offset, sizeof(uint64_t)); |
| if (ret < 0) { |
| return ret; |
| } |
| |
| s->l1_vm_state_index = new_l1_size; |
| return 0; |
| } |
| |
| /* XXX: put compressed sectors first, then all the cluster aligned |
| tables to avoid losing bytes in alignment */ |
| static int qcow2_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 == 0) { |
| /* align end of file to a sector boundary to ease reading with |
| sector based I/Os */ |
| cluster_offset = bdrv_getlength(bs->file); |
| cluster_offset = (cluster_offset + 511) & ~511; |
| bdrv_truncate(bs->file, cluster_offset); |
| return 0; |
| } |
| |
| if (nb_sectors != s->cluster_sectors) |
| return -EINVAL; |
| |
| 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 = qcow2_alloc_compressed_cluster_offset(bs, |
| sector_num << 9, out_len); |
| if (!cluster_offset) { |
| ret = -EIO; |
| goto fail; |
| } |
| cluster_offset &= s->cluster_offset_mask; |
| BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED); |
| ret = bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len); |
| if (ret < 0) { |
| goto fail; |
| } |
| } |
| |
| ret = 0; |
| fail: |
| g_free(out_buf); |
| return ret; |
| } |
| |
| static int qcow2_co_flush(BlockDriverState *bs) |
| { |
| BDRVQcowState *s = bs->opaque; |
| int ret; |
| |
| qemu_co_mutex_lock(&s->lock); |
| ret = qcow2_cache_flush(bs, s->l2_table_cache); |
| if (ret < 0) { |
| return ret; |
| } |
| |
| ret = qcow2_cache_flush(bs, s->refcount_block_cache); |
| if (ret < 0) { |
| return ret; |
| } |
| qemu_co_mutex_unlock(&s->lock); |
| |
| return bdrv_co_flush(bs->file); |
| } |
| |
| static int64_t qcow2_vm_state_offset(BDRVQcowState *s) |
| { |
| return (int64_t)s->l1_vm_state_index << (s->cluster_bits + s->l2_bits); |
| } |
| |
| static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) |
| { |
| BDRVQcowState *s = bs->opaque; |
| bdi->cluster_size = s->cluster_size; |
| bdi->vm_state_offset = qcow2_vm_state_offset(s); |
| return 0; |
| } |
| |
| |
| static int qcow2_check(BlockDriverState *bs, BdrvCheckResult *result) |
| { |
| return qcow2_check_refcounts(bs, result); |
| } |
| |
| #if 0 |
| static void dump_refcounts(BlockDriverState *bs) |
| { |
| BDRVQcowState *s = bs->opaque; |
| int64_t nb_clusters, k, k1, size; |
| int refcount; |
| |
| size = bdrv_getlength(bs->file); |
| nb_clusters = size_to_clusters(s, size); |
| for(k = 0; k < nb_clusters;) { |
| k1 = k; |
| refcount = get_refcount(bs, k); |
| k++; |
| while (k < nb_clusters && get_refcount(bs, k) == refcount) |
| k++; |
| printf("%" PRId64 ": refcount=%d nb=%" PRId64 "\n", k, refcount, |
| k - k1); |
| } |
| } |
| #endif |
| |
| static int qcow2_save_vmstate(BlockDriverState *bs, const uint8_t *buf, |
| int64_t pos, int size) |
| { |
| BDRVQcowState *s = bs->opaque; |
| int growable = bs->growable; |
| int ret; |
| |
| BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE); |
| bs->growable = 1; |
| ret = bdrv_pwrite(bs, qcow2_vm_state_offset(s) + pos, buf, size); |
| bs->growable = growable; |
| |
| return ret; |
| } |
| |
| static int qcow2_load_vmstate(BlockDriverState *bs, uint8_t *buf, |
| int64_t pos, int size) |
| { |
| BDRVQcowState *s = bs->opaque; |
| int growable = bs->growable; |
| int ret; |
| |
| BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD); |
| bs->growable = 1; |
| ret = bdrv_pread(bs, qcow2_vm_state_offset(s) + pos, buf, size); |
| bs->growable = growable; |
| |
| return ret; |
| } |
| |
| static QEMUOptionParameter qcow2_create_options[] = { |
| { |
| .name = BLOCK_OPT_SIZE, |
| .type = OPT_SIZE, |
| .help = "Virtual disk size" |
| }, |
| { |
| .name = BLOCK_OPT_BACKING_FILE, |
| .type = OPT_STRING, |
| .help = "File name of a base image" |
| }, |
| { |
| .name = BLOCK_OPT_BACKING_FMT, |
| .type = OPT_STRING, |
| .help = "Image format of the base image" |
| }, |
| { |
| .name = BLOCK_OPT_ENCRYPT, |
| .type = OPT_FLAG, |
| .help = "Encrypt the image" |
| }, |
| { |
| .name = BLOCK_OPT_CLUSTER_SIZE, |
| .type = OPT_SIZE, |
| .help = "qcow2 cluster size", |
| .value = { .n = DEFAULT_CLUSTER_SIZE }, |
| }, |
| { |
| .name = BLOCK_OPT_PREALLOC, |
| .type = OPT_STRING, |
| .help = "Preallocation mode (allowed values: off, metadata)" |
| }, |
| { NULL } |
| }; |
| |
| static BlockDriver bdrv_qcow2 = { |
| .format_name = "qcow2", |
| .instance_size = sizeof(BDRVQcowState), |
| .bdrv_probe = qcow2_probe, |
| .bdrv_open = qcow2_open, |
| .bdrv_close = qcow2_close, |
| .bdrv_create = qcow2_create, |
| .bdrv_is_allocated = qcow2_is_allocated, |
| .bdrv_set_key = qcow2_set_key, |
| .bdrv_make_empty = qcow2_make_empty, |
| |
| .bdrv_co_readv = qcow2_co_readv, |
| .bdrv_co_writev = qcow2_co_writev, |
| .bdrv_co_flush = qcow2_co_flush, |
| |
| .bdrv_co_discard = qcow2_co_discard, |
| .bdrv_truncate = qcow2_truncate, |
| .bdrv_write_compressed = qcow2_write_compressed, |
| |
| .bdrv_snapshot_create = qcow2_snapshot_create, |
| .bdrv_snapshot_goto = qcow2_snapshot_goto, |
| .bdrv_snapshot_delete = qcow2_snapshot_delete, |
| .bdrv_snapshot_list = qcow2_snapshot_list, |
| .bdrv_snapshot_load_tmp = qcow2_snapshot_load_tmp, |
| .bdrv_get_info = qcow2_get_info, |
| |
| .bdrv_save_vmstate = qcow2_save_vmstate, |
| .bdrv_load_vmstate = qcow2_load_vmstate, |
| |
| .bdrv_change_backing_file = qcow2_change_backing_file, |
| |
| .create_options = qcow2_create_options, |
| .bdrv_check = qcow2_check, |
| }; |
| |
| static void bdrv_qcow2_init(void) |
| { |
| bdrv_register(&bdrv_qcow2); |
| } |
| |
| block_init(bdrv_qcow2_init); |