| /* |
| * 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" |
| |
| /* |
| 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. |
| */ |
| |
| //#define DEBUG_ALLOC |
| //#define DEBUG_ALLOC2 |
| //#define DEBUG_EXT |
| |
| |
| typedef struct { |
| uint32_t magic; |
| uint32_t len; |
| } QCowExtension; |
| #define QCOW_EXT_MAGIC_END 0 |
| #define QCOW_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA |
| |
| |
| |
| 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; |
| } |
| |
| |
| /* |
| * 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 qcow_read_extensions(BlockDriverState *bs, uint64_t start_offset, |
| uint64_t end_offset) |
| { |
| BDRVQcowState *s = bs->opaque; |
| QCowExtension ext; |
| uint64_t offset; |
| |
| #ifdef DEBUG_EXT |
| printf("qcow_read_extensions: start=%ld end=%ld\n", start_offset, end_offset); |
| #endif |
| offset = start_offset; |
| while (offset < end_offset) { |
| |
| #ifdef DEBUG_EXT |
| /* Sanity check */ |
| if (offset > s->cluster_size) |
| printf("qcow_handle_extension: suspicious offset %lu\n", offset); |
| |
| printf("attemting to read extended header in offset %lu\n", offset); |
| #endif |
| |
| if (bdrv_pread(s->hd, offset, &ext, sizeof(ext)) != sizeof(ext)) { |
| fprintf(stderr, "qcow_handle_extension: ERROR: pread fail from offset %llu\n", |
| (unsigned long long)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 QCOW_EXT_MAGIC_END: |
| return 0; |
| |
| case QCOW_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(s->hd, 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 += ((ext.len + 7) & ~7); |
| break; |
| |
| default: |
| /* unknown magic -- just skip it */ |
| offset += ((ext.len + 7) & ~7); |
| break; |
| } |
| } |
| |
| return 0; |
| } |
| |
| |
| static int qcow_open(BlockDriverState *bs, const char *filename, int flags) |
| { |
| BDRVQcowState *s = bs->opaque; |
| int len, i, shift, ret; |
| QCowHeader header; |
| uint64_t ext_end; |
| |
| /* Performance is terrible right now with cache=writethrough due mainly |
| * to reference count updates. If the user does not explicitly specify |
| * a caching type, force to writeback caching. |
| */ |
| if ((flags & BDRV_O_CACHE_DEF)) { |
| flags |= BDRV_O_CACHE_WB; |
| flags &= ~BDRV_O_CACHE_DEF; |
| } |
| ret = bdrv_file_open(&s->hd, filename, flags); |
| if (ret < 0) |
| return ret; |
| if (bdrv_pread(s->hd, 0, &header, sizeof(header)) != sizeof(header)) |
| 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 || header.version != QCOW_VERSION) |
| goto fail; |
| if (header.size <= 1 || |
| header.cluster_bits < MIN_CLUSTER_BITS || |
| header.cluster_bits > MAX_CLUSTER_BITS) |
| goto fail; |
| if (header.crypt_method > QCOW_CRYPT_AES) |
| 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; |
| shift = s->cluster_bits + s->l2_bits; |
| s->l1_vm_state_index = (header.size + (1LL << shift) - 1) >> shift; |
| /* the L1 table must contain at least enough entries to put |
| header.size bytes */ |
| if (s->l1_size < s->l1_vm_state_index) |
| goto fail; |
| s->l1_table_offset = header.l1_table_offset; |
| s->l1_table = qemu_malloc(s->l1_size * sizeof(uint64_t)); |
| if (bdrv_pread(s->hd, s->l1_table_offset, s->l1_table, s->l1_size * sizeof(uint64_t)) != |
| s->l1_size * sizeof(uint64_t)) |
| goto fail; |
| for(i = 0;i < s->l1_size; i++) { |
| be64_to_cpus(&s->l1_table[i]); |
| } |
| /* alloc L2 cache */ |
| s->l2_cache = qemu_malloc(s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); |
| s->cluster_cache = qemu_malloc(s->cluster_size); |
| /* one more sector for decompressed data alignment */ |
| s->cluster_data = qemu_malloc(QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size |
| + 512); |
| s->cluster_cache_offset = -1; |
| |
| if (qcow2_refcount_init(bs) < 0) |
| goto fail; |
| |
| /* read qcow2 extensions */ |
| if (header.backing_file_offset) |
| ext_end = header.backing_file_offset; |
| else |
| ext_end = s->cluster_size; |
| if (qcow_read_extensions(bs, sizeof(header), ext_end)) |
| goto fail; |
| |
| /* read the backing file name */ |
| if (header.backing_file_offset != 0) { |
| len = header.backing_file_size; |
| if (len > 1023) |
| len = 1023; |
| if (bdrv_pread(s->hd, header.backing_file_offset, bs->backing_file, len) != len) |
| goto fail; |
| bs->backing_file[len] = '\0'; |
| } |
| if (qcow2_read_snapshots(bs) < 0) |
| goto fail; |
| |
| #ifdef DEBUG_ALLOC |
| check_refcounts(bs); |
| #endif |
| return 0; |
| |
| fail: |
| qcow2_free_snapshots(bs); |
| qcow2_refcount_close(bs); |
| qemu_free(s->l1_table); |
| qemu_free(s->l2_cache); |
| qemu_free(s->cluster_cache); |
| qemu_free(s->cluster_data); |
| bdrv_delete(s->hd); |
| return -1; |
| } |
| |
| static int qcow_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 qcow_is_allocated(BlockDriverState *bs, int64_t sector_num, |
| int nb_sectors, int *pnum) |
| { |
| uint64_t cluster_offset; |
| |
| *pnum = nb_sectors; |
| cluster_offset = qcow2_get_cluster_offset(bs, sector_num << 9, pnum); |
| |
| return (cluster_offset != 0); |
| } |
| |
| /* handle reading after the end of the backing file */ |
| int qcow2_backing_read1(BlockDriverState *bs, |
| int64_t sector_num, uint8_t *buf, 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; |
| memset(buf + n1 * 512, 0, 512 * (nb_sectors - n1)); |
| return n1; |
| } |
| |
| typedef struct QCowAIOCB { |
| BlockDriverAIOCB common; |
| int64_t sector_num; |
| QEMUIOVector *qiov; |
| uint8_t *buf; |
| void *orig_buf; |
| int nb_sectors; |
| int n; |
| uint64_t cluster_offset; |
| uint8_t *cluster_data; |
| BlockDriverAIOCB *hd_aiocb; |
| struct iovec hd_iov; |
| QEMUIOVector hd_qiov; |
| QEMUBH *bh; |
| QCowL2Meta l2meta; |
| } QCowAIOCB; |
| |
| static void qcow_aio_cancel(BlockDriverAIOCB *blockacb) |
| { |
| QCowAIOCB *acb = (QCowAIOCB *)blockacb; |
| if (acb->hd_aiocb) |
| bdrv_aio_cancel(acb->hd_aiocb); |
| qemu_aio_release(acb); |
| } |
| |
| static AIOPool qcow_aio_pool = { |
| .aiocb_size = sizeof(QCowAIOCB), |
| .cancel = qcow_aio_cancel, |
| }; |
| |
| static void qcow_aio_read_cb(void *opaque, int ret); |
| static void qcow_aio_read_bh(void *opaque) |
| { |
| QCowAIOCB *acb = opaque; |
| qemu_bh_delete(acb->bh); |
| acb->bh = NULL; |
| qcow_aio_read_cb(opaque, 0); |
| } |
| |
| static int qcow_schedule_bh(QEMUBHFunc *cb, QCowAIOCB *acb) |
| { |
| if (acb->bh) |
| return -EIO; |
| |
| acb->bh = qemu_bh_new(cb, acb); |
| if (!acb->bh) |
| return -EIO; |
| |
| qemu_bh_schedule(acb->bh); |
| |
| return 0; |
| } |
| |
| static void qcow_aio_read_cb(void *opaque, int ret) |
| { |
| QCowAIOCB *acb = opaque; |
| BlockDriverState *bs = acb->common.bs; |
| BDRVQcowState *s = bs->opaque; |
| int index_in_cluster, n1; |
| |
| acb->hd_aiocb = NULL; |
| if (ret < 0) |
| goto done; |
| |
| /* post process the read buffer */ |
| if (!acb->cluster_offset) { |
| /* nothing to do */ |
| } else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) { |
| /* nothing to do */ |
| } else { |
| if (s->crypt_method) { |
| qcow2_encrypt_sectors(s, acb->sector_num, acb->buf, acb->buf, |
| acb->n, 0, |
| &s->aes_decrypt_key); |
| } |
| } |
| |
| acb->nb_sectors -= acb->n; |
| acb->sector_num += acb->n; |
| acb->buf += acb->n * 512; |
| |
| if (acb->nb_sectors == 0) { |
| /* request completed */ |
| ret = 0; |
| goto done; |
| } |
| |
| /* prepare next AIO request */ |
| acb->n = acb->nb_sectors; |
| acb->cluster_offset = |
| qcow2_get_cluster_offset(bs, acb->sector_num << 9, &acb->n); |
| index_in_cluster = acb->sector_num & (s->cluster_sectors - 1); |
| |
| if (!acb->cluster_offset) { |
| if (bs->backing_hd) { |
| /* read from the base image */ |
| n1 = qcow2_backing_read1(bs->backing_hd, acb->sector_num, |
| acb->buf, acb->n); |
| if (n1 > 0) { |
| acb->hd_iov.iov_base = (void *)acb->buf; |
| acb->hd_iov.iov_len = acb->n * 512; |
| qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1); |
| acb->hd_aiocb = bdrv_aio_readv(bs->backing_hd, acb->sector_num, |
| &acb->hd_qiov, acb->n, |
| qcow_aio_read_cb, acb); |
| if (acb->hd_aiocb == NULL) |
| goto done; |
| } else { |
| ret = qcow_schedule_bh(qcow_aio_read_bh, acb); |
| if (ret < 0) |
| goto done; |
| } |
| } else { |
| /* Note: in this case, no need to wait */ |
| memset(acb->buf, 0, 512 * acb->n); |
| ret = qcow_schedule_bh(qcow_aio_read_bh, acb); |
| if (ret < 0) |
| goto done; |
| } |
| } else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) { |
| /* add AIO support for compressed blocks ? */ |
| if (qcow2_decompress_cluster(s, acb->cluster_offset) < 0) |
| goto done; |
| memcpy(acb->buf, |
| s->cluster_cache + index_in_cluster * 512, 512 * acb->n); |
| ret = qcow_schedule_bh(qcow_aio_read_bh, acb); |
| if (ret < 0) |
| goto done; |
| } else { |
| if ((acb->cluster_offset & 511) != 0) { |
| ret = -EIO; |
| goto done; |
| } |
| |
| acb->hd_iov.iov_base = (void *)acb->buf; |
| acb->hd_iov.iov_len = acb->n * 512; |
| qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1); |
| acb->hd_aiocb = bdrv_aio_readv(s->hd, |
| (acb->cluster_offset >> 9) + index_in_cluster, |
| &acb->hd_qiov, acb->n, qcow_aio_read_cb, acb); |
| if (acb->hd_aiocb == NULL) |
| goto done; |
| } |
| |
| return; |
| done: |
| if (acb->qiov->niov > 1) { |
| qemu_iovec_from_buffer(acb->qiov, acb->orig_buf, acb->qiov->size); |
| qemu_vfree(acb->orig_buf); |
| } |
| acb->common.cb(acb->common.opaque, ret); |
| qemu_aio_release(acb); |
| } |
| |
| static QCowAIOCB *qcow_aio_setup(BlockDriverState *bs, |
| int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, |
| BlockDriverCompletionFunc *cb, void *opaque, int is_write) |
| { |
| QCowAIOCB *acb; |
| |
| acb = qemu_aio_get(&qcow_aio_pool, bs, cb, opaque); |
| if (!acb) |
| return NULL; |
| acb->hd_aiocb = NULL; |
| acb->sector_num = sector_num; |
| acb->qiov = qiov; |
| if (qiov->niov > 1) { |
| acb->buf = acb->orig_buf = qemu_blockalign(bs, qiov->size); |
| if (is_write) |
| qemu_iovec_to_buffer(qiov, acb->buf); |
| } else { |
| acb->buf = (uint8_t *)qiov->iov->iov_base; |
| } |
| acb->nb_sectors = nb_sectors; |
| acb->n = 0; |
| acb->cluster_offset = 0; |
| acb->l2meta.nb_clusters = 0; |
| return acb; |
| } |
| |
| static BlockDriverAIOCB *qcow_aio_readv(BlockDriverState *bs, |
| int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, |
| BlockDriverCompletionFunc *cb, void *opaque) |
| { |
| QCowAIOCB *acb; |
| |
| acb = qcow_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 0); |
| if (!acb) |
| return NULL; |
| |
| qcow_aio_read_cb(acb, 0); |
| return &acb->common; |
| } |
| |
| static void qcow_aio_write_cb(void *opaque, int ret) |
| { |
| QCowAIOCB *acb = opaque; |
| BlockDriverState *bs = acb->common.bs; |
| BDRVQcowState *s = bs->opaque; |
| int index_in_cluster; |
| const uint8_t *src_buf; |
| int n_end; |
| |
| acb->hd_aiocb = NULL; |
| |
| if (ret < 0) |
| goto done; |
| |
| if (qcow2_alloc_cluster_link_l2(bs, acb->cluster_offset, &acb->l2meta) < 0) { |
| qcow2_free_any_clusters(bs, acb->cluster_offset, acb->l2meta.nb_clusters); |
| goto done; |
| } |
| |
| acb->nb_sectors -= acb->n; |
| acb->sector_num += acb->n; |
| acb->buf += acb->n * 512; |
| |
| if (acb->nb_sectors == 0) { |
| /* request completed */ |
| ret = 0; |
| goto done; |
| } |
| |
| index_in_cluster = acb->sector_num & (s->cluster_sectors - 1); |
| n_end = index_in_cluster + acb->nb_sectors; |
| if (s->crypt_method && |
| n_end > QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors) |
| n_end = QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors; |
| |
| acb->cluster_offset = qcow2_alloc_cluster_offset(bs, acb->sector_num << 9, |
| index_in_cluster, |
| n_end, &acb->n, &acb->l2meta); |
| if (!acb->cluster_offset || (acb->cluster_offset & 511) != 0) { |
| ret = -EIO; |
| goto done; |
| } |
| if (s->crypt_method) { |
| if (!acb->cluster_data) { |
| acb->cluster_data = qemu_mallocz(QCOW_MAX_CRYPT_CLUSTERS * |
| s->cluster_size); |
| } |
| qcow2_encrypt_sectors(s, acb->sector_num, acb->cluster_data, acb->buf, |
| acb->n, 1, &s->aes_encrypt_key); |
| src_buf = acb->cluster_data; |
| } else { |
| src_buf = acb->buf; |
| } |
| acb->hd_iov.iov_base = (void *)src_buf; |
| acb->hd_iov.iov_len = acb->n * 512; |
| qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1); |
| acb->hd_aiocb = bdrv_aio_writev(s->hd, |
| (acb->cluster_offset >> 9) + index_in_cluster, |
| &acb->hd_qiov, acb->n, |
| qcow_aio_write_cb, acb); |
| if (acb->hd_aiocb == NULL) |
| goto done; |
| |
| return; |
| |
| done: |
| if (acb->qiov->niov > 1) |
| qemu_vfree(acb->orig_buf); |
| acb->common.cb(acb->common.opaque, ret); |
| qemu_aio_release(acb); |
| } |
| |
| static BlockDriverAIOCB *qcow_aio_writev(BlockDriverState *bs, |
| int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, |
| BlockDriverCompletionFunc *cb, void *opaque) |
| { |
| BDRVQcowState *s = bs->opaque; |
| QCowAIOCB *acb; |
| |
| s->cluster_cache_offset = -1; /* disable compressed cache */ |
| |
| acb = qcow_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 1); |
| if (!acb) |
| return NULL; |
| |
| qcow_aio_write_cb(acb, 0); |
| return &acb->common; |
| } |
| |
| static void qcow_close(BlockDriverState *bs) |
| { |
| BDRVQcowState *s = bs->opaque; |
| qemu_free(s->l1_table); |
| qemu_free(s->l2_cache); |
| qemu_free(s->cluster_cache); |
| qemu_free(s->cluster_data); |
| qcow2_refcount_close(bs); |
| bdrv_delete(s->hd); |
| } |
| |
| static int get_bits_from_size(size_t size) |
| { |
| int res = 0; |
| |
| if (size == 0) { |
| return -1; |
| } |
| |
| while (size != 1) { |
| /* Not a power of two */ |
| if (size & 1) { |
| return -1; |
| } |
| |
| size >>= 1; |
| res++; |
| } |
| |
| return res; |
| } |
| |
| static int qcow_create2(const char *filename, int64_t total_size, |
| const char *backing_file, const char *backing_format, |
| int flags, size_t cluster_size) |
| { |
| |
| int fd, header_size, backing_filename_len, l1_size, i, shift, l2_bits; |
| int ref_clusters, backing_format_len = 0; |
| QCowHeader header; |
| uint64_t tmp, offset; |
| QCowCreateState s1, *s = &s1; |
| QCowExtension ext_bf = {0, 0}; |
| |
| |
| memset(s, 0, sizeof(*s)); |
| |
| fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644); |
| if (fd < 0) |
| return -1; |
| 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 * 512); |
| header_size = sizeof(header); |
| backing_filename_len = 0; |
| if (backing_file) { |
| if (backing_format) { |
| ext_bf.magic = QCOW_EXT_MAGIC_BACKING_FORMAT; |
| backing_format_len = strlen(backing_format); |
| ext_bf.len = (backing_format_len + 7) & ~7; |
| header_size += ((sizeof(ext_bf) + ext_bf.len + 7) & ~7); |
| } |
| 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; |
| } |
| |
| /* Cluster size */ |
| s->cluster_bits = get_bits_from_size(cluster_size); |
| if (s->cluster_bits < MIN_CLUSTER_BITS || |
| s->cluster_bits > MAX_CLUSTER_BITS) |
| { |
| fprintf(stderr, "Cluster size must be a power of two between " |
| "%d and %dk\n", |
| 1 << MIN_CLUSTER_BITS, |
| 1 << (MAX_CLUSTER_BITS - 10)); |
| return -EINVAL; |
| } |
| s->cluster_size = 1 << s->cluster_bits; |
| |
| header.cluster_bits = cpu_to_be32(s->cluster_bits); |
| header_size = (header_size + 7) & ~7; |
| if (flags & BLOCK_FLAG_ENCRYPT) { |
| header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES); |
| } else { |
| header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); |
| } |
| l2_bits = s->cluster_bits - 3; |
| shift = s->cluster_bits + l2_bits; |
| l1_size = (((total_size * 512) + (1LL << shift) - 1) >> shift); |
| offset = align_offset(header_size, s->cluster_size); |
| s->l1_table_offset = offset; |
| header.l1_table_offset = cpu_to_be64(s->l1_table_offset); |
| header.l1_size = cpu_to_be32(l1_size); |
| offset += align_offset(l1_size * sizeof(uint64_t), s->cluster_size); |
| |
| s->refcount_table = qemu_mallocz(s->cluster_size); |
| |
| s->refcount_table_offset = offset; |
| header.refcount_table_offset = cpu_to_be64(offset); |
| header.refcount_table_clusters = cpu_to_be32(1); |
| offset += s->cluster_size; |
| s->refcount_block_offset = offset; |
| |
| /* count how many refcount blocks needed */ |
| tmp = offset >> s->cluster_bits; |
| ref_clusters = (tmp >> (s->cluster_bits - REFCOUNT_SHIFT)) + 1; |
| for (i=0; i < ref_clusters; i++) { |
| s->refcount_table[i] = cpu_to_be64(offset); |
| offset += s->cluster_size; |
| } |
| |
| s->refcount_block = qemu_mallocz(ref_clusters * s->cluster_size); |
| |
| /* update refcounts */ |
| qcow2_create_refcount_update(s, 0, header_size); |
| qcow2_create_refcount_update(s, s->l1_table_offset, |
| l1_size * sizeof(uint64_t)); |
| qcow2_create_refcount_update(s, s->refcount_table_offset, s->cluster_size); |
| qcow2_create_refcount_update(s, s->refcount_block_offset, |
| ref_clusters * s->cluster_size); |
| |
| /* write all the data */ |
| write(fd, &header, sizeof(header)); |
| if (backing_file) { |
| if (backing_format_len) { |
| char zero[16]; |
| int d = ext_bf.len - backing_format_len; |
| |
| memset(zero, 0, sizeof(zero)); |
| cpu_to_be32s(&ext_bf.magic); |
| cpu_to_be32s(&ext_bf.len); |
| write(fd, &ext_bf, sizeof(ext_bf)); |
| write(fd, backing_format, backing_format_len); |
| if (d>0) { |
| write(fd, zero, d); |
| } |
| } |
| write(fd, backing_file, backing_filename_len); |
| } |
| lseek(fd, s->l1_table_offset, SEEK_SET); |
| tmp = 0; |
| for(i = 0;i < l1_size; i++) { |
| write(fd, &tmp, sizeof(tmp)); |
| } |
| lseek(fd, s->refcount_table_offset, SEEK_SET); |
| write(fd, s->refcount_table, s->cluster_size); |
| |
| lseek(fd, s->refcount_block_offset, SEEK_SET); |
| write(fd, s->refcount_block, ref_clusters * s->cluster_size); |
| |
| qemu_free(s->refcount_table); |
| qemu_free(s->refcount_block); |
| close(fd); |
| return 0; |
| } |
| |
| static int qcow_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 = 65536; |
| |
| /* 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; |
| } |
| } |
| options++; |
| } |
| |
| return qcow_create2(filename, sectors, backing_file, backing_fmt, flags, |
| cluster_size); |
| } |
| |
| static int qcow_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(s->hd, s->l1_table_offset, s->l1_table, l1_length) < 0) |
| return -1; |
| ret = bdrv_truncate(s->hd, s->l1_table_offset + l1_length); |
| if (ret < 0) |
| return ret; |
| |
| l2_cache_reset(bs); |
| #endif |
| 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 == 0) { |
| /* align end of file to a sector boundary to ease reading with |
| sector based I/Os */ |
| cluster_offset = bdrv_getlength(s->hd); |
| cluster_offset = (cluster_offset + 511) & ~511; |
| bdrv_truncate(s->hd, cluster_offset); |
| return 0; |
| } |
| |
| if (nb_sectors != s->cluster_sectors) |
| return -EINVAL; |
| |
| out_buf = qemu_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) { |
| qemu_free(out_buf); |
| return -1; |
| } |
| |
| 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) { |
| qemu_free(out_buf); |
| deflateEnd(&strm); |
| return -1; |
| } |
| 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 */ |
| bdrv_write(bs, sector_num, buf, s->cluster_sectors); |
| } else { |
| cluster_offset = qcow2_alloc_compressed_cluster_offset(bs, |
| sector_num << 9, out_len); |
| if (!cluster_offset) |
| return -1; |
| cluster_offset &= s->cluster_offset_mask; |
| if (bdrv_pwrite(s->hd, cluster_offset, out_buf, out_len) != out_len) { |
| qemu_free(out_buf); |
| return -1; |
| } |
| } |
| |
| qemu_free(out_buf); |
| return 0; |
| } |
| |
| static void qcow_flush(BlockDriverState *bs) |
| { |
| BDRVQcowState *s = bs->opaque; |
| bdrv_flush(s->hd); |
| } |
| |
| static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) |
| { |
| BDRVQcowState *s = bs->opaque; |
| bdi->cluster_size = s->cluster_size; |
| bdi->vm_state_offset = (int64_t)s->l1_vm_state_index << |
| (s->cluster_bits + s->l2_bits); |
| return 0; |
| } |
| |
| |
| static int qcow_check(BlockDriverState *bs) |
| { |
| return qcow2_check_refcounts(bs); |
| } |
| |
| #if 0 |
| static void dump_refcounts(BlockDriverState *bs) |
| { |
| BDRVQcowState *s = bs->opaque; |
| int64_t nb_clusters, k, k1, size; |
| int refcount; |
| |
| size = bdrv_getlength(s->hd); |
| 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("%lld: refcount=%d nb=%lld\n", k, refcount, k - k1); |
| } |
| } |
| #endif |
| |
| static int qcow_put_buffer(BlockDriverState *bs, const uint8_t *buf, |
| int64_t pos, int size) |
| { |
| int growable = bs->growable; |
| |
| bs->growable = 1; |
| bdrv_pwrite(bs, pos, buf, size); |
| bs->growable = growable; |
| |
| return size; |
| } |
| |
| static int qcow_get_buffer(BlockDriverState *bs, uint8_t *buf, |
| int64_t pos, int size) |
| { |
| int growable = bs->growable; |
| int ret; |
| |
| bs->growable = 1; |
| ret = bdrv_pread(bs, pos, buf, size); |
| bs->growable = growable; |
| |
| return ret; |
| } |
| |
| static QEMUOptionParameter qcow_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" |
| }, |
| { NULL } |
| }; |
| |
| static BlockDriver bdrv_qcow2 = { |
| .format_name = "qcow2", |
| .instance_size = sizeof(BDRVQcowState), |
| .bdrv_probe = qcow_probe, |
| .bdrv_open = qcow_open, |
| .bdrv_close = qcow_close, |
| .bdrv_create = qcow_create, |
| .bdrv_flush = qcow_flush, |
| .bdrv_is_allocated = qcow_is_allocated, |
| .bdrv_set_key = qcow_set_key, |
| .bdrv_make_empty = qcow_make_empty, |
| |
| .bdrv_aio_readv = qcow_aio_readv, |
| .bdrv_aio_writev = qcow_aio_writev, |
| .bdrv_write_compressed = qcow_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_get_info = qcow_get_info, |
| |
| .bdrv_put_buffer = qcow_put_buffer, |
| .bdrv_get_buffer = qcow_get_buffer, |
| |
| .create_options = qcow_create_options, |
| .bdrv_check = qcow_check, |
| }; |
| |
| static void bdrv_qcow2_init(void) |
| { |
| bdrv_register(&bdrv_qcow2); |
| } |
| |
| block_init(bdrv_qcow2_init); |
