diff options
Diffstat (limited to 'block/qcow2.c')
| -rw-r--r-- | block/qcow2.c | 1027 |
1 files changed, 1027 insertions, 0 deletions
diff --git a/block/qcow2.c b/block/qcow2.c new file mode 100644 index 0000000..9acbddf --- /dev/null +++ b/block/qcow2.c @@ -0,0 +1,1027 @@ +/* + * 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); |