diff options
Diffstat (limited to 'block-qcow2.c')
| -rw-r--r-- | block-qcow2.c | 2236 |
1 files changed, 2236 insertions, 0 deletions
diff --git a/block-qcow2.c b/block-qcow2.c new file mode 100644 index 0000000000..f499b13be1 --- /dev/null +++ b/block-qcow2.c @@ -0,0 +1,2236 @@ +/* + * 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 "vl.h" +#include "block_int.h" +#include <zlib.h> +#include "aes.h" +#include <assert.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 QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb) +#define QCOW_VERSION 2 + +#define QCOW_CRYPT_NONE 0 +#define QCOW_CRYPT_AES 1 + +/* indicate that the refcount of the referenced cluster is exactly one. */ +#define QCOW_OFLAG_COPIED (1LL << 63) +/* indicate that the cluster is compressed (they never have the copied flag) */ +#define QCOW_OFLAG_COMPRESSED (1LL << 62) + +#define REFCOUNT_SHIFT 1 /* refcount size is 2 bytes */ + +#ifndef offsetof +#define offsetof(type, field) ((size_t) &((type *)0)->field) +#endif + +typedef struct QCowHeader { + uint32_t magic; + uint32_t version; + uint64_t backing_file_offset; + uint32_t backing_file_size; + uint32_t cluster_bits; + uint64_t size; /* in bytes */ + uint32_t crypt_method; + uint32_t l1_size; /* XXX: save number of clusters instead ? */ + uint64_t l1_table_offset; + uint64_t refcount_table_offset; + uint32_t refcount_table_clusters; + uint32_t nb_snapshots; + uint64_t snapshots_offset; +} QCowHeader; + +typedef struct __attribute__((packed)) QCowSnapshotHeader { + /* header is 8 byte aligned */ + uint64_t l1_table_offset; + + uint32_t l1_size; + uint16_t id_str_size; + uint16_t name_size; + + uint32_t date_sec; + uint32_t date_nsec; + + uint64_t vm_clock_nsec; + + uint32_t vm_state_size; + uint32_t extra_data_size; /* for extension */ + /* extra data follows */ + /* id_str follows */ + /* name follows */ +} QCowSnapshotHeader; + +#define L2_CACHE_SIZE 16 + +typedef struct QCowSnapshot { + uint64_t l1_table_offset; + uint32_t l1_size; + char *id_str; + char *name; + uint32_t vm_state_size; + uint32_t date_sec; + uint32_t date_nsec; + uint64_t vm_clock_nsec; +} QCowSnapshot; + +typedef struct BDRVQcowState { + BlockDriverState *hd; + int cluster_bits; + int cluster_size; + int cluster_sectors; + int l2_bits; + int l2_size; + int l1_size; + int l1_vm_state_index; + int csize_shift; + int csize_mask; + uint64_t cluster_offset_mask; + uint64_t l1_table_offset; + uint64_t *l1_table; + uint64_t *l2_cache; + uint64_t l2_cache_offsets[L2_CACHE_SIZE]; + uint32_t l2_cache_counts[L2_CACHE_SIZE]; + uint8_t *cluster_cache; + uint8_t *cluster_data; + uint64_t cluster_cache_offset; + + uint64_t *refcount_table; + uint64_t refcount_table_offset; + uint32_t refcount_table_size; + uint64_t refcount_block_cache_offset; + uint16_t *refcount_block_cache; + int64_t free_cluster_index; + int64_t free_byte_offset; + + uint32_t crypt_method; /* current crypt method, 0 if no key yet */ + uint32_t crypt_method_header; + AES_KEY aes_encrypt_key; + AES_KEY aes_decrypt_key; + uint64_t snapshots_offset; + int snapshots_size; + int nb_snapshots; + QCowSnapshot *snapshots; +} BDRVQcowState; + +static int decompress_cluster(BDRVQcowState *s, uint64_t cluster_offset); +static int qcow_read(BlockDriverState *bs, int64_t sector_num, + uint8_t *buf, int nb_sectors); +static int qcow_read_snapshots(BlockDriverState *bs); +static void qcow_free_snapshots(BlockDriverState *bs); +static int refcount_init(BlockDriverState *bs); +static void refcount_close(BlockDriverState *bs); +static int get_refcount(BlockDriverState *bs, int64_t cluster_index); +static int update_cluster_refcount(BlockDriverState *bs, + int64_t cluster_index, + int addend); +static void update_refcount(BlockDriverState *bs, + int64_t offset, int64_t length, + int addend); +static int64_t alloc_clusters(BlockDriverState *bs, int64_t size); +static int64_t alloc_bytes(BlockDriverState *bs, int size); +static void free_clusters(BlockDriverState *bs, + int64_t offset, int64_t size); +#ifdef DEBUG_ALLOC +static void check_refcounts(BlockDriverState *bs); +#endif + +static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename) +{ + const QCowHeader *cow_header = (const void *)buf; + + if (buf_size >= sizeof(QCowHeader) && + be32_to_cpu(cow_header->magic) == QCOW_MAGIC && + be32_to_cpu(cow_header->version) == QCOW_VERSION) + return 100; + else + return 0; +} + +static int qcow_open(BlockDriverState *bs, const char *filename, int flags) +{ + BDRVQcowState *s = bs->opaque; + int len, i, shift, ret; + QCowHeader header; + + 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 < 9 || + header.cluster_bits > 16) + 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 (!s->l1_table) + goto fail; + 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)); + if (!s->l2_cache) + goto fail; + s->cluster_cache = qemu_malloc(s->cluster_size); + if (!s->cluster_cache) + goto fail; + /* one more sector for decompressed data alignment */ + s->cluster_data = qemu_malloc(s->cluster_size + 512); + if (!s->cluster_data) + goto fail; + s->cluster_cache_offset = -1; + + if (refcount_init(bs) < 0) + 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 (qcow_read_snapshots(bs) < 0) + goto fail; + +#ifdef DEBUG_ALLOC + check_refcounts(bs); +#endif + return 0; + + fail: + qcow_free_snapshots(bs); + 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; +} + +/* The crypt function is compatible with the linux cryptoloop + algorithm for < 4 GB images. NOTE: out_buf == in_buf is + supported */ +static void encrypt_sectors(BDRVQcowState *s, int64_t sector_num, + uint8_t *out_buf, const uint8_t *in_buf, + int nb_sectors, int enc, + const AES_KEY *key) +{ + union { + uint64_t ll[2]; + uint8_t b[16]; + } ivec; + int i; + + for(i = 0; i < nb_sectors; i++) { + ivec.ll[0] = cpu_to_le64(sector_num); + ivec.ll[1] = 0; + AES_cbc_encrypt(in_buf, out_buf, 512, key, + ivec.b, enc); + sector_num++; + in_buf += 512; + out_buf += 512; + } +} + +static int copy_sectors(BlockDriverState *bs, uint64_t start_sect, + uint64_t cluster_offset, int n_start, int n_end) +{ + BDRVQcowState *s = bs->opaque; + int n, ret; + + n = n_end - n_start; + if (n <= 0) + return 0; + ret = qcow_read(bs, start_sect + n_start, s->cluster_data, n); + if (ret < 0) + return ret; + if (s->crypt_method) { + encrypt_sectors(s, start_sect + n_start, + s->cluster_data, + s->cluster_data, n, 1, + &s->aes_encrypt_key); + } + ret = bdrv_write(s->hd, (cluster_offset >> 9) + n_start, + s->cluster_data, n); + if (ret < 0) + return ret; + return 0; +} + +static void l2_cache_reset(BlockDriverState *bs) +{ + BDRVQcowState *s = bs->opaque; + + memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); + memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t)); + memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t)); +} + +static inline int l2_cache_new_entry(BlockDriverState *bs) +{ + BDRVQcowState *s = bs->opaque; + uint32_t min_count; + int min_index, i; + + /* find a new entry in the least used one */ + min_index = 0; + min_count = 0xffffffff; + for(i = 0; i < L2_CACHE_SIZE; i++) { + if (s->l2_cache_counts[i] < min_count) { + min_count = s->l2_cache_counts[i]; + min_index = i; + } + } + return min_index; +} + +static int64_t align_offset(int64_t offset, int n) +{ + offset = (offset + n - 1) & ~(n - 1); + return offset; +} + +static int grow_l1_table(BlockDriverState *bs, int min_size) +{ + BDRVQcowState *s = bs->opaque; + int new_l1_size, new_l1_size2, ret, i; + uint64_t *new_l1_table; + uint64_t new_l1_table_offset; + uint64_t data64; + uint32_t data32; + + new_l1_size = s->l1_size; + if (min_size <= new_l1_size) + return 0; + while (min_size > new_l1_size) { + new_l1_size = (new_l1_size * 3 + 1) / 2; + } +#ifdef DEBUG_ALLOC2 + printf("grow l1_table from %d to %d\n", s->l1_size, new_l1_size); +#endif + + new_l1_size2 = sizeof(uint64_t) * new_l1_size; + new_l1_table = qemu_mallocz(new_l1_size2); + if (!new_l1_table) + return -ENOMEM; + memcpy(new_l1_table, s->l1_table, s->l1_size * sizeof(uint64_t)); + + /* write new table (align to cluster) */ + new_l1_table_offset = alloc_clusters(bs, new_l1_size2); + + for(i = 0; i < s->l1_size; i++) + new_l1_table[i] = cpu_to_be64(new_l1_table[i]); + ret = bdrv_pwrite(s->hd, new_l1_table_offset, new_l1_table, new_l1_size2); + if (ret != new_l1_size2) + goto fail; + for(i = 0; i < s->l1_size; i++) + new_l1_table[i] = be64_to_cpu(new_l1_table[i]); + + /* set new table */ + data64 = cpu_to_be64(new_l1_table_offset); + if (bdrv_pwrite(s->hd, offsetof(QCowHeader, l1_table_offset), + &data64, sizeof(data64)) != sizeof(data64)) + goto fail; + data32 = cpu_to_be32(new_l1_size); + if (bdrv_pwrite(s->hd, offsetof(QCowHeader, l1_size), + &data32, sizeof(data32)) != sizeof(data32)) + goto fail; + qemu_free(s->l1_table); + free_clusters(bs, s->l1_table_offset, s->l1_size * sizeof(uint64_t)); + s->l1_table_offset = new_l1_table_offset; + s->l1_table = new_l1_table; + s->l1_size = new_l1_size; + return 0; + fail: + qemu_free(s->l1_table); + return -EIO; +} + +/* 'allocate' is: + * + * 0 not to allocate. + * + * 1 to allocate a normal cluster (for sector indexes 'n_start' to + * 'n_end') + * + * 2 to allocate a compressed cluster of size + * 'compressed_size'. 'compressed_size' must be > 0 and < + * cluster_size + * + * return 0 if not allocated. + */ +static uint64_t get_cluster_offset(BlockDriverState *bs, + uint64_t offset, int allocate, + int compressed_size, + int n_start, int n_end) +{ + BDRVQcowState *s = bs->opaque; + int min_index, i, j, l1_index, l2_index, ret; + uint64_t l2_offset, *l2_table, cluster_offset, tmp, old_l2_offset; + + l1_index = offset >> (s->l2_bits + s->cluster_bits); + if (l1_index >= s->l1_size) { + /* outside l1 table is allowed: we grow the table if needed */ + if (!allocate) + return 0; + if (grow_l1_table(bs, l1_index + 1) < 0) + return 0; + } + l2_offset = s->l1_table[l1_index]; + if (!l2_offset) { + if (!allocate) + return 0; + l2_allocate: + old_l2_offset = l2_offset; + /* allocate a new l2 entry */ + l2_offset = alloc_clusters(bs, s->l2_size * sizeof(uint64_t)); + /* update the L1 entry */ + s->l1_table[l1_index] = l2_offset | QCOW_OFLAG_COPIED; + tmp = cpu_to_be64(l2_offset | QCOW_OFLAG_COPIED); + if (bdrv_pwrite(s->hd, s->l1_table_offset + l1_index * sizeof(tmp), + &tmp, sizeof(tmp)) != sizeof(tmp)) + return 0; + min_index = l2_cache_new_entry(bs); + l2_table = s->l2_cache + (min_index << s->l2_bits); + + if (old_l2_offset == 0) { + memset(l2_table, 0, s->l2_size * sizeof(uint64_t)); + } else { + if (bdrv_pread(s->hd, old_l2_offset, + l2_table, s->l2_size * sizeof(uint64_t)) != + s->l2_size * sizeof(uint64_t)) + return 0; + } + if (bdrv_pwrite(s->hd, l2_offset, + l2_table, s->l2_size * sizeof(uint64_t)) != + s->l2_size * sizeof(uint64_t)) + return 0; + } else { + if (!(l2_offset & QCOW_OFLAG_COPIED)) { + if (allocate) { + free_clusters(bs, l2_offset, s->l2_size * sizeof(uint64_t)); + goto l2_allocate; + } + } else { + l2_offset &= ~QCOW_OFLAG_COPIED; + } + for(i = 0; i < L2_CACHE_SIZE; i++) { + if (l2_offset == s->l2_cache_offsets[i]) { + /* increment the hit count */ + if (++s->l2_cache_counts[i] == 0xffffffff) { + for(j = 0; j < L2_CACHE_SIZE; j++) { + s->l2_cache_counts[j] >>= 1; + } + } + l2_table = s->l2_cache + (i << s->l2_bits); + goto found; + } + } + /* not found: load a new entry in the least used one */ + min_index = l2_cache_new_entry(bs); + l2_table = s->l2_cache + (min_index << s->l2_bits); + if (bdrv_pread(s->hd, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) != + s->l2_size * sizeof(uint64_t)) + return 0; + } + s->l2_cache_offsets[min_index] = l2_offset; + s->l2_cache_counts[min_index] = 1; + found: + l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1); + cluster_offset = be64_to_cpu(l2_table[l2_index]); + if (!cluster_offset) { + if (!allocate) + return cluster_offset; + } else if (!(cluster_offset & QCOW_OFLAG_COPIED)) { + if (!allocate) + return cluster_offset; + /* free the cluster */ + if (cluster_offset & QCOW_OFLAG_COMPRESSED) { + int nb_csectors; + nb_csectors = ((cluster_offset >> s->csize_shift) & + s->csize_mask) + 1; + free_clusters(bs, (cluster_offset & s->cluster_offset_mask) & ~511, + nb_csectors * 512); + } else { + free_clusters(bs, cluster_offset, s->cluster_size); + } + } else { + cluster_offset &= ~QCOW_OFLAG_COPIED; + return cluster_offset; + } + if (allocate == 1) { + /* allocate a new cluster */ + cluster_offset = alloc_clusters(bs, s->cluster_size); + + /* we must initialize the cluster content which won't be + written */ + if ((n_end - n_start) < s->cluster_sectors) { + uint64_t start_sect; + + start_sect = (offset & ~(s->cluster_size - 1)) >> 9; + ret = copy_sectors(bs, start_sect, + cluster_offset, 0, n_start); + if (ret < 0) + return 0; + ret = copy_sectors(bs, start_sect, + cluster_offset, n_end, s->cluster_sectors); + if (ret < 0) + return 0; + } + tmp = cpu_to_be64(cluster_offset | QCOW_OFLAG_COPIED); + } else { + int nb_csectors; + cluster_offset = alloc_bytes(bs, compressed_size); + nb_csectors = ((cluster_offset + compressed_size - 1) >> 9) - + (cluster_offset >> 9); + cluster_offset |= QCOW_OFLAG_COMPRESSED | + ((uint64_t)nb_csectors << s->csize_shift); + /* compressed clusters never have the copied flag */ + tmp = cpu_to_be64(cluster_offset); + } + /* update L2 table */ + l2_table[l2_index] = tmp; + if (bdrv_pwrite(s->hd, + l2_offset + l2_index * sizeof(tmp), &tmp, sizeof(tmp)) != sizeof(tmp)) + return 0; + return cluster_offset; +} + +static int qcow_is_allocated(BlockDriverState *bs, int64_t sector_num, + int nb_sectors, int *pnum) +{ + BDRVQcowState *s = bs->opaque; + int index_in_cluster, n; + uint64_t cluster_offset; + + cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0); + index_in_cluster = sector_num & (s->cluster_sectors - 1); + n = s->cluster_sectors - index_in_cluster; + if (n > nb_sectors) + n = nb_sectors; + *pnum = n; + return (cluster_offset != 0); +} + +static int decompress_buffer(uint8_t *out_buf, int out_buf_size, + const uint8_t *buf, int buf_size) +{ + z_stream strm1, *strm = &strm1; + int ret, out_len; + + memset(strm, 0, sizeof(*strm)); + + strm->next_in = (uint8_t *)buf; + strm->avail_in = buf_size; + strm->next_out = out_buf; + strm->avail_out = out_buf_size; + + ret = inflateInit2(strm, -12); + if (ret != Z_OK) + return -1; + ret = inflate(strm, Z_FINISH); + out_len = strm->next_out - out_buf; + if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) || + out_len != out_buf_size) { + inflateEnd(strm); + return -1; + } + inflateEnd(strm); + return 0; +} + +static int decompress_cluster(BDRVQcowState *s, uint64_t cluster_offset) +{ + int ret, csize, nb_csectors, sector_offset; + uint64_t coffset; + + coffset = cluster_offset & s->cluster_offset_mask; + if (s->cluster_cache_offset != coffset) { + nb_csectors = ((cluster_offset >> s->csize_shift) & s->csize_mask) + 1; + sector_offset = coffset & 511; + csize = nb_csectors * 512 - sector_offset; + ret = bdrv_read(s->hd, coffset >> 9, s->cluster_data, nb_csectors); + if (ret < 0) { + return -1; + } + if (decompress_buffer(s->cluster_cache, s->cluster_size, + s->cluster_data + sector_offset, csize) < 0) { + return -1; + } + s->cluster_cache_offset = coffset; + } + return 0; +} + +static int qcow_read(BlockDriverState *bs, int64_t sector_num, + uint8_t *buf, int nb_sectors) +{ + BDRVQcowState *s = bs->opaque; + int ret, index_in_cluster, n; + uint64_t cluster_offset; + + while (nb_sectors > 0) { + cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0); + index_in_cluster = sector_num & (s->cluster_sectors - 1); + n = s->cluster_sectors - index_in_cluster; + if (n > nb_sectors) + n = nb_sectors; + if (!cluster_offset) { + if (bs->backing_hd) { + /* read from the base image */ + ret = bdrv_read(bs->backing_hd, sector_num, buf, n); + if (ret < 0) + return -1; + } else { + memset(buf, 0, 512 * n); + } + } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) { + if (decompress_cluster(s, cluster_offset) < 0) + return -1; + memcpy(buf, s->cluster_cache + index_in_cluster * 512, 512 * n); + } else { + ret = bdrv_pread(s->hd, cluster_offset + index_in_cluster * 512, buf, n * 512); + if (ret != n * 512) + return -1; + if (s->crypt_method) { + encrypt_sectors(s, sector_num, buf, buf, n, 0, + &s->aes_decrypt_key); + } + } + nb_sectors -= n; + sector_num += n; + buf += n * 512; + } + return 0; +} + +static int qcow_write(BlockDriverState *bs, int64_t sector_num, + const uint8_t *buf, int nb_sectors) +{ + BDRVQcowState *s = bs->opaque; + int ret, index_in_cluster, n; + uint64_t cluster_offset; + + while (nb_sectors > 0) { + index_in_cluster = sector_num & (s->cluster_sectors - 1); + n = s->cluster_sectors - index_in_cluster; + if (n > nb_sectors) + n = nb_sectors; + cluster_offset = get_cluster_offset(bs, sector_num << 9, 1, 0, + index_in_cluster, + index_in_cluster + n); + if (!cluster_offset) + return -1; + if (s->crypt_method) { + encrypt_sectors(s, sector_num, s->cluster_data, buf, n, 1, + &s->aes_encrypt_key); + ret = bdrv_pwrite(s->hd, cluster_offset + index_in_cluster * 512, + s->cluster_data, n * 512); + } else { + ret = bdrv_pwrite(s->hd, cluster_offset + index_in_cluster * 512, buf, n * 512); + } + if (ret != n * 512) + return -1; + nb_sectors -= n; + sector_num += n; + buf += n * 512; + } + s->cluster_cache_offset = -1; /* disable compressed cache */ + return 0; +} + +typedef struct { + int64_t sector_num; + uint8_t *buf; + int nb_sectors; + int n; + uint64_t cluster_offset; + uint8_t *cluster_data; + BlockDriverAIOCB *hd_aiocb; + BlockDriverAIOCB *backing_hd_aiocb; +} QCowAIOCB; + +static void qcow_aio_delete(BlockDriverAIOCB *acb); + +static int qcow_aio_new(BlockDriverAIOCB *acb) +{ + BlockDriverState *bs = acb->bs; + BDRVQcowState *s = bs->opaque; + QCowAIOCB *acb1; + acb1 = qemu_mallocz(sizeof(QCowAIOCB)); + if (!acb1) + return -1; + acb->opaque = acb1; + acb1->hd_aiocb = bdrv_aio_new(s->hd); + if (!acb1->hd_aiocb) + goto fail; + if (bs->backing_hd) { + acb1->backing_hd_aiocb = bdrv_aio_new(bs->backing_hd); + if (!acb1->backing_hd_aiocb) + goto fail; + } + return 0; + fail: + qcow_aio_delete(acb); + return -1; +} + +static void qcow_aio_read_cb(void *opaque, int ret) +{ + BlockDriverAIOCB *acb = opaque; + BlockDriverState *bs = acb->bs; + BDRVQcowState *s = bs->opaque; + QCowAIOCB *acb1 = acb->opaque; + int index_in_cluster; + + if (ret < 0) { + fail: + acb->cb(acb->cb_opaque, ret); + return; + } + + redo: + /* post process the read buffer */ + if (!acb1->cluster_offset) { + /* nothing to do */ + } else if (acb1->cluster_offset & QCOW_OFLAG_COMPRESSED) { + /* nothing to do */ + } else { + if (s->crypt_method) { + encrypt_sectors(s, acb1->sector_num, acb1->buf, acb1->buf, + acb1->n, 0, + &s->aes_decrypt_key); + } + } + + acb1->nb_sectors -= acb1->n; + acb1->sector_num += acb1->n; + acb1->buf += acb1->n * 512; + + if (acb1->nb_sectors == 0) { + /* request completed */ + acb->cb(acb->cb_opaque, 0); + return; + } + + /* prepare next AIO request */ + acb1->cluster_offset = get_cluster_offset(bs, + acb1->sector_num << 9, + 0, 0, 0, 0); + index_in_cluster = acb1->sector_num & (s->cluster_sectors - 1); + acb1->n = s->cluster_sectors - index_in_cluster; + if (acb1->n > acb1->nb_sectors) + acb1->n = acb1->nb_sectors; + + if (!acb1->cluster_offset) { + if (bs->backing_hd) { + /* read from the base image */ + ret = bdrv_aio_read(acb1->backing_hd_aiocb, acb1->sector_num, + acb1->buf, acb1->n, qcow_aio_read_cb, acb); + if (ret < 0) + goto fail; + } else { + /* Note: in this case, no need to wait */ + memset(acb1->buf, 0, 512 * acb1->n); + goto redo; + } + } else if (acb1->cluster_offset & QCOW_OFLAG_COMPRESSED) { + /* add AIO support for compressed blocks ? */ + if (decompress_cluster(s, acb1->cluster_offset) < 0) + goto fail; + memcpy(acb1->buf, + s->cluster_cache + index_in_cluster * 512, 512 * acb1->n); + goto redo; + } else { + if ((acb1->cluster_offset & 511) != 0) { + ret = -EIO; + goto fail; + } + ret = bdrv_aio_read(acb1->hd_aiocb, + (acb1->cluster_offset >> 9) + index_in_cluster, + acb1->buf, acb1->n, qcow_aio_read_cb, acb); + if (ret < 0) + goto fail; + } +} + +static int qcow_aio_read(BlockDriverAIOCB *acb, int64_t sector_num, + uint8_t *buf, int nb_sectors) +{ + QCowAIOCB *acb1 = acb->opaque; + + acb1->sector_num = sector_num; + acb1->buf = buf; + acb1->nb_sectors = nb_sectors; + acb1->n = 0; + acb1->cluster_offset = 0; + + qcow_aio_read_cb(acb, 0); + return 0; +} + +static void qcow_aio_write_cb(void *opaque, int ret) +{ + BlockDriverAIOCB *acb = opaque; + BlockDriverState *bs = acb->bs; + BDRVQcowState *s = bs->opaque; + QCowAIOCB *acb1 = acb->opaque; + int index_in_cluster; + uint64_t cluster_offset; + const uint8_t *src_buf; + + if (ret < 0) { + fail: + acb->cb(acb->cb_opaque, ret); + return; + } + + acb1->nb_sectors -= acb1->n; + acb1->sector_num += acb1->n; + acb1->buf += acb1->n * 512; + + if (acb1->nb_sectors == 0) { + /* request completed */ + acb->cb(acb->cb_opaque, 0); + return; + } + + index_in_cluster = acb1->sector_num & (s->cluster_sectors - 1); + acb1->n = s->cluster_sectors - index_in_cluster; + if (acb1->n > acb1->nb_sectors) + acb1->n = acb1->nb_sectors; + cluster_offset = get_cluster_offset(bs, acb1->sector_num << 9, 1, 0, + index_in_cluster, + index_in_cluster + acb1->n); + if (!cluster_offset || (cluster_offset & 511) != 0) { + ret = -EIO; + goto fail; + } + if (s->crypt_method) { + if (!acb1->cluster_data) { + acb1->cluster_data = qemu_mallocz(s->cluster_size); + if (!acb1->cluster_data) { + ret = -ENOMEM; + goto fail; + } + } + encrypt_sectors(s, acb1->sector_num, acb1->cluster_data, acb1->buf, + acb1->n, 1, &s->aes_encrypt_key); + src_buf = acb1->cluster_data; + } else { + src_buf = acb1->buf; + } + ret = bdrv_aio_write(acb1->hd_aiocb, + (cluster_offset >> 9) + index_in_cluster, + src_buf, acb1->n, + qcow_aio_write_cb, acb); + if (ret < 0) + goto fail; +} + +static int qcow_aio_write(BlockDriverAIOCB *acb, int64_t sector_num, + const uint8_t *buf, int nb_sectors) +{ + QCowAIOCB *acb1 = acb->opaque; + BlockDriverState *bs = acb->bs; + BDRVQcowState *s = bs->opaque; + + s->cluster_cache_offset = -1; /* disable compressed cache */ + + acb1->sector_num = sector_num; + acb1->buf = (uint8_t *)buf; + acb1->nb_sectors = nb_sectors; + acb1->n = 0; + + qcow_aio_write_cb(acb, 0); + return 0; +} + +static void qcow_aio_cancel(BlockDriverAIOCB *acb) +{ + QCowAIOCB *acb1 = acb->opaque; + if (acb1->hd_aiocb) + bdrv_aio_cancel(acb1->hd_aiocb); + if (acb1->backing_hd_aiocb) + bdrv_aio_cancel(acb1->backing_hd_aiocb); +} + +static void qcow_aio_delete(BlockDriverAIOCB *acb) +{ + QCowAIOCB *acb1 = acb->opaque; + if (acb1->hd_aiocb) + bdrv_aio_delete(acb1->hd_aiocb); + if (acb1->backing_hd_aiocb) + bdrv_aio_delete(acb1->backing_hd_aiocb); + qemu_free(acb1->cluster_data); + qemu_free(acb1); +} + +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); + refcount_close(bs); + bdrv_delete(s->hd); +} + +/* XXX: use std qcow open function ? */ +typedef struct QCowCreateState { + int cluster_size; + int cluster_bits; + uint16_t *refcount_block; + uint64_t *refcount_table; + int64_t l1_table_offset; + int64_t refcount_table_offset; + int64_t refcount_block_offset; +} QCowCreateState; + +static void create_refcount_update(QCowCreateState *s, + int64_t offset, int64_t size) +{ + int refcount; + int64_t start, last, cluster_offset; + uint16_t *p; + + start = offset & ~(s->cluster_size - 1); + last = (offset + size - 1) & ~(s->cluster_size - 1); + for(cluster_offset = start; cluster_offset <= last; + cluster_offset += s->cluster_size) { + p = &s->refcount_block[cluster_offset >> s->cluster_bits]; + refcount = be16_to_cpu(*p); + refcount++; + *p = cpu_to_be16(refcount); + } +} + +static int qcow_create(const char *filename, int64_t total_size, + const char *backing_file, int flags) +{ + int fd, header_size, backing_filename_len, l1_size, i, shift, l2_bits; + QCowHeader header; + uint64_t tmp, offset; + QCowCreateState s1, *s = &s1; + + 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) { + 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; + } + s->cluster_bits = 12; /* 4 KB clusters */ + s->cluster_size = 1 << s->cluster_bits; + header.cluster_bits = cpu_to_be32(s->cluster_bits); + header_size = (header_size + 7) & ~7; + if (flags) { + 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, s->cluster_size); + + s->refcount_table = qemu_mallocz(s->cluster_size); + if (!s->refcount_table) + goto fail; + s->refcount_block = qemu_mallocz(s->cluster_size); + if (!s->refcount_block) + goto fail; + + 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_table[0] = cpu_to_be64(offset); + s->refcount_block_offset = offset; + offset += s->cluster_size; + + /* update refcounts */ + create_refcount_update(s, 0, header_size); + create_refcount_update(s, s->l1_table_offset, l1_size); + create_refcount_update(s, s->refcount_table_offset, s->cluster_size); + create_refcount_update(s, s->refcount_block_offset, s->cluster_size); + + /* write all the data */ + write(fd, &header, sizeof(header)); + if (backing_file) { + 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, s->cluster_size); + + qemu_free(s->refcount_table); + qemu_free(s->refcount_block); + close(fd); + return 0; + fail: + qemu_free(s->refcount_table); + qemu_free(s->refcount_block); + close(fd); + return -ENOMEM; +} + +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); + if (!out_buf) + return -ENOMEM; + + /* 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 */ + qcow_write(bs, sector_num, buf, s->cluster_sectors); + } else { + cluster_offset = get_cluster_offset(bs, sector_num << 9, 2, + out_len, 0, 0); + 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; +} + +/*********************************************************/ +/* snapshot support */ + +/* update the refcounts of snapshots and the copied flag */ +static int update_snapshot_refcount(BlockDriverState *bs, + int64_t l1_table_offset, + int l1_size, + int addend) +{ + BDRVQcowState *s = bs->opaque; + uint64_t *l1_table, *l2_table, l2_offset, offset, l1_size2, l1_allocated; + int64_t old_offset, old_l2_offset; + int l2_size, i, j, l1_modified, l2_modified, nb_csectors, refcount; + + l2_cache_reset(bs); + + l2_table = NULL; + l1_table = NULL; + l1_size2 = l1_size * sizeof(uint64_t); + l1_allocated = 0; + if (l1_table_offset != s->l1_table_offset) { + l1_table = qemu_malloc(l1_size2); + if (!l1_table) + goto fail; + l1_allocated = 1; + if (bdrv_pread(s->hd, l1_table_offset, + l1_table, l1_size2) != l1_size2) + goto fail; + for(i = 0;i < l1_size; i++) + be64_to_cpus(&l1_table[i]); + } else { + assert(l1_size == s->l1_size); + l1_table = s->l1_table; + l1_allocated = 0; + } + + l2_size = s->l2_size * sizeof(uint64_t); + l2_table = qemu_malloc(l2_size); + if (!l2_table) + goto fail; + l1_modified = 0; + for(i = 0; i < l1_size; i++) { + l2_offset = l1_table[i]; + if (l2_offset) { + old_l2_offset = l2_offset; + l2_offset &= ~QCOW_OFLAG_COPIED; + l2_modified = 0; + if (bdrv_pread(s->hd, l2_offset, l2_table, l2_size) != l2_size) + goto fail; + for(j = 0; j < s->l2_size; j++) { + offset = be64_to_cpu(l2_table[j]); + if (offset != 0) { + old_offset = offset; + offset &= ~QCOW_OFLAG_COPIED; + if (offset & QCOW_OFLAG_COMPRESSED) { + nb_csectors = ((offset >> s->csize_shift) & + s->csize_mask) + 1; + if (addend != 0) + update_refcount(bs, (offset & s->cluster_offset_mask) & ~511, + nb_csectors * 512, addend); + /* compressed clusters are never modified */ + refcount = 2; + } else { + if (addend != 0) { + refcount = update_cluster_refcount(bs, offset >> s->cluster_bits, addend); + } else { + refcount = get_refcount(bs, offset >> s->cluster_bits); + } + } + + if (refcount == 1) { + offset |= QCOW_OFLAG_COPIED; + } + if (offset != old_offset) { + l2_table[j] = cpu_to_be64(offset); + l2_modified = 1; + } + } + } + if (l2_modified) { + if (bdrv_pwrite(s->hd, + l2_offset, l2_table, l2_size) != l2_size) + goto fail; + } + + if (addend != 0) { + refcount = update_cluster_refcount(bs, l2_offset >> s->cluster_bits, addend); + } else { + refcount = get_refcount(bs, l2_offset >> s->cluster_bits); + } + if (refcount == 1) { + l2_offset |= QCOW_OFLAG_COPIED; + } + if (l2_offset != old_l2_offset) { + l1_table[i] = l2_offset; + l1_modified = 1; + } + } + } + if (l1_modified) { + for(i = 0; i < l1_size; i++) + cpu_to_be64s(&l1_table[i]); + if (bdrv_pwrite(s->hd, l1_table_offset, l1_table, + l1_size2) != l1_size2) + goto fail; + for(i = 0; i < l1_size; i++) + be64_to_cpus(&l1_table[i]); + } + if (l1_allocated) + qemu_free(l1_table); + qemu_free(l2_table); + return 0; + fail: + if (l1_allocated) + qemu_free(l1_table); + qemu_free(l2_table); + return -EIO; +} + +static void qcow_free_snapshots(BlockDriverState *bs) +{ + BDRVQcowState *s = bs->opaque; + int i; + + for(i = 0; i < s->nb_snapshots; i++) { + qemu_free(s->snapshots[i].name); + qemu_free(s->snapshots[i].id_str); + } + qemu_free(s->snapshots); + s->snapshots = NULL; + s->nb_snapshots = 0; +} + +static int qcow_read_snapshots(BlockDriverState *bs) +{ + BDRVQcowState *s = bs->opaque; + QCowSnapshotHeader h; + QCowSnapshot *sn; + int i, id_str_size, name_size; + int64_t offset; + uint32_t extra_data_size; + + offset = s->snapshots_offset; + s->snapshots = qemu_mallocz(s->nb_snapshots * sizeof(QCowSnapshot)); + if (!s->snapshots) + goto fail; + for(i = 0; i < s->nb_snapshots; i++) { + offset = align_offset(offset, 8); + if (bdrv_pread(s->hd, offset, &h, sizeof(h)) != sizeof(h)) + goto fail; + offset += sizeof(h); + sn = s->snapshots + i; + sn->l1_table_offset = be64_to_cpu(h.l1_table_offset); + sn->l1_size = be32_to_cpu(h.l1_size); + sn->vm_state_size = be32_to_cpu(h.vm_state_size); + sn->date_sec = be32_to_cpu(h.date_sec); + sn->date_nsec = be32_to_cpu(h.date_nsec); + sn->vm_clock_nsec = be64_to_cpu(h.vm_clock_nsec); + extra_data_size = be32_to_cpu(h.extra_data_size); + + id_str_size = be16_to_cpu(h.id_str_size); + name_size = be16_to_cpu(h.name_size); + + offset += extra_data_size; + + sn->id_str = qemu_malloc(id_str_size + 1); + if (!sn->id_str) + goto fail; + if (bdrv_pread(s->hd, offset, sn->id_str, id_str_size) != id_str_size) + goto fail; + offset += id_str_size; + sn->id_str[id_str_size] = '\0'; + + sn->name = qemu_malloc(name_size + 1); + if (!sn->name) + goto fail; + if (bdrv_pread(s->hd, offset, sn->name, name_size) != name_size) + goto fail; + offset += name_size; + sn->name[name_size] = '\0'; + } + s->snapshots_size = offset - s->snapshots_offset; + return 0; + fail: + qcow_free_snapshots(bs); + return -1; +} + +/* add at the end of the file a new list of snapshots */ +static int qcow_write_snapshots(BlockDriverState *bs) +{ + BDRVQcowState *s = bs->opaque; + QCowSnapshot *sn; + QCowSnapshotHeader h; + int i, name_size, id_str_size, snapshots_size; + uint64_t data64; + uint32_t data32; + int64_t offset, snapshots_offset; + + /* compute the size of the snapshots */ + offset = 0; + for(i = 0; i < s->nb_snapshots; i++) { + sn = s->snapshots + i; + offset = align_offset(offset, 8); + offset += sizeof(h); + offset += strlen(sn->id_str); + offset += strlen(sn->name); + } + snapshots_size = offset; + + snapshots_offset = alloc_clusters(bs, snapshots_size); + offset = snapshots_offset; + + for(i = 0; i < s->nb_snapshots; i++) { + sn = s->snapshots + i; + memset(&h, 0, sizeof(h)); + h.l1_table_offset = cpu_to_be64(sn->l1_table_offset); + h.l1_size = cpu_to_be32(sn->l1_size); + h.vm_state_size = cpu_to_be32(sn->vm_state_size); + h.date_sec = cpu_to_be32(sn->date_sec); + h.date_nsec = cpu_to_be32(sn->date_nsec); + h.vm_clock_nsec = cpu_to_be64(sn->vm_clock_nsec); + + id_str_size = strlen(sn->id_str); + name_size = strlen(sn->name); + h.id_str_size = cpu_to_be16(id_str_size); + h.name_size = cpu_to_be16(name_size); + offset = align_offset(offset, 8); + if (bdrv_pwrite(s->hd, offset, &h, sizeof(h)) != sizeof(h)) + goto fail; + offset += sizeof(h); + if (bdrv_pwrite(s->hd, offset, sn->id_str, id_str_size) != id_str_size) + goto fail; + offset += id_str_size; + if (bdrv_pwrite(s->hd, offset, sn->name, name_size) != name_size) + goto fail; + offset += name_size; + } + + /* update the various header fields */ + data64 = cpu_to_be64(snapshots_offset); + if (bdrv_pwrite(s->hd, offsetof(QCowHeader, snapshots_offset), + &data64, sizeof(data64)) != sizeof(data64)) + goto fail; + data32 = cpu_to_be32(s->nb_snapshots); + if (bdrv_pwrite(s->hd, offsetof(QCowHeader, nb_snapshots), + &data32, sizeof(data32)) != sizeof(data32)) + goto fail; + + /* free the old snapshot table */ + free_clusters(bs, s->snapshots_offset, s->snapshots_size); + s->snapshots_offset = snapshots_offset; + s->snapshots_size = snapshots_size; + return 0; + fail: + return -1; +} + +static void find_new_snapshot_id(BlockDriverState *bs, + char *id_str, int id_str_size) +{ + BDRVQcowState *s = bs->opaque; + QCowSnapshot *sn; + int i, id, id_max = 0; + + for(i = 0; i < s->nb_snapshots; i++) { + sn = s->snapshots + i; + id = strtoul(sn->id_str, NULL, 10); + if (id > id_max) + id_max = id; + } + snprintf(id_str, id_str_size, "%d", id_max + 1); +} + +static int find_snapshot_by_id(BlockDriverState *bs, const char *id_str) +{ + BDRVQcowState *s = bs->opaque; + int i; + + for(i = 0; i < s->nb_snapshots; i++) { + if (!strcmp(s->snapshots[i].id_str, id_str)) + return i; + } + return -1; +} + +static int find_snapshot_by_id_or_name(BlockDriverState *bs, const char *name) +{ + BDRVQcowState *s = bs->opaque; + int i, ret; + + ret = find_snapshot_by_id(bs, name); + if (ret >= 0) + return ret; + for(i = 0; i < s->nb_snapshots; i++) { + if (!strcmp(s->snapshots[i].name, name)) + return i; + } + return -1; +} + +/* if no id is provided, a new one is constructed */ +static int qcow_snapshot_create(BlockDriverState *bs, + QEMUSnapshotInfo *sn_info) +{ + BDRVQcowState *s = bs->opaque; + QCowSnapshot *snapshots1, sn1, *sn = &sn1; + int i, ret; + uint64_t *l1_table = NULL; + + memset(sn, 0, sizeof(*sn)); + + if (sn_info->id_str[0] == '\0') { + /* compute a new id */ + find_new_snapshot_id(bs, sn_info->id_str, sizeof(sn_info->id_str)); + } + + /* check that the ID is unique */ + if (find_snapshot_by_id(bs, sn_info->id_str) >= 0) + return -ENOENT; + + sn->id_str = qemu_strdup(sn_info->id_str); + if (!sn->id_str) + goto fail; + sn->name = qemu_strdup(sn_info->name); + if (!sn->name) + goto fail; + sn->vm_state_size = sn_info->vm_state_size; + sn->date_sec = sn_info->date_sec; + sn->date_nsec = sn_info->date_nsec; + sn->vm_clock_nsec = sn_info->vm_clock_nsec; + + ret = update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 1); + if (ret < 0) + goto fail; + + /* create the L1 table of the snapshot */ + sn->l1_table_offset = alloc_clusters(bs, s->l1_size * sizeof(uint64_t)); + sn->l1_size = s->l1_size; + + l1_table = qemu_malloc(s->l1_size * sizeof(uint64_t)); + if (!l1_table) + goto fail; + for(i = 0; i < s->l1_size; i++) { + l1_table[i] = cpu_to_be64(s->l1_table[i]); + } + if (bdrv_pwrite(s->hd, sn->l1_table_offset, + l1_table, s->l1_size * sizeof(uint64_t)) != + (s->l1_size * sizeof(uint64_t))) + goto fail; + qemu_free(l1_table); + l1_table = NULL; + + snapshots1 = qemu_malloc((s->nb_snapshots + 1) * sizeof(QCowSnapshot)); + if (!snapshots1) + goto fail; + memcpy(snapshots1, s->snapshots, s->nb_snapshots * sizeof(QCowSnapshot)); + s->snapshots = snapshots1; + s->snapshots[s->nb_snapshots++] = *sn; + + if (qcow_write_snapshots(bs) < 0) + goto fail; +#ifdef DEBUG_ALLOC + check_refcounts(bs); +#endif + return 0; + fail: + qemu_free(sn->name); + qemu_free(l1_table); + return -1; +} + +/* copy the snapshot 'snapshot_name' into the current disk image */ +static int qcow_snapshot_goto(BlockDriverState *bs, + const char *snapshot_id) +{ + BDRVQcowState *s = bs->opaque; + QCowSnapshot *sn; + int i, snapshot_index, l1_size2; + + snapshot_index = find_snapshot_by_id_or_name(bs, snapshot_id); + if (snapshot_index < 0) + return -ENOENT; + sn = &s->snapshots[snapshot_index]; + + if (update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, -1) < 0) + goto fail; + + if (grow_l1_table(bs, sn->l1_size) < 0) + goto fail; + + s->l1_size = sn->l1_size; + l1_size2 = s->l1_size * sizeof(uint64_t); + /* copy the snapshot l1 table to the current l1 table */ + if (bdrv_pread(s->hd, sn->l1_table_offset, + s->l1_table, l1_size2) != l1_size2) + goto fail; + if (bdrv_pwrite(s->hd, s->l1_table_offset, + s->l1_table, l1_size2) != l1_size2) + goto fail; + for(i = 0;i < s->l1_size; i++) { + be64_to_cpus(&s->l1_table[i]); + } + + if (update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 1) < 0) + goto fail; + +#ifdef DEBUG_ALLOC + check_refcounts(bs); +#endif + return 0; + fail: + return -EIO; +} + +static int qcow_snapshot_delete(BlockDriverState *bs, const char *snapshot_id) +{ + BDRVQcowState *s = bs->opaque; + QCowSnapshot *sn; + int snapshot_index, ret; + + snapshot_index = find_snapshot_by_id_or_name(bs, snapshot_id); + if (snapshot_index < 0) + return -ENOENT; + sn = &s->snapshots[snapshot_index]; + + ret = update_snapshot_refcount(bs, sn->l1_table_offset, sn->l1_size, -1); + if (ret < 0) + return ret; + /* must update the copied flag on the current cluster offsets */ + ret = update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 0); + if (ret < 0) + return ret; + free_clusters(bs, sn->l1_table_offset, sn->l1_size * sizeof(uint64_t)); + + qemu_free(sn->id_str); + qemu_free(sn->name); + memmove(sn, sn + 1, (s->nb_snapshots - snapshot_index - 1) * sizeof(*sn)); + s->nb_snapshots--; + ret = qcow_write_snapshots(bs); + if (ret < 0) { + /* XXX: restore snapshot if error ? */ + return ret; + } +#ifdef DEBUG_ALLOC + check_refcounts(bs); +#endif + return 0; +} + +static int qcow_snapshot_list(BlockDriverState *bs, + QEMUSnapshotInfo **psn_tab) +{ + BDRVQcowState *s = bs->opaque; + QEMUSnapshotInfo *sn_tab, *sn_info; + QCowSnapshot *sn; + int i; + + sn_tab = qemu_mallocz(s->nb_snapshots * sizeof(QEMUSnapshotInfo)); + if (!sn_tab) + goto fail; + for(i = 0; i < s->nb_snapshots; i++) { + sn_info = sn_tab + i; + sn = s->snapshots + i; + pstrcpy(sn_info->id_str, sizeof(sn_info->id_str), + sn->id_str); + pstrcpy(sn_info->name, sizeof(sn_info->name), + sn->name); + sn_info->vm_state_size = sn->vm_state_size; + sn_info->date_sec = sn->date_sec; + sn_info->date_nsec = sn->date_nsec; + sn_info->vm_clock_nsec = sn->vm_clock_nsec; + } + *psn_tab = sn_tab; + return s->nb_snapshots; + fail: + qemu_free(sn_tab); + *psn_tab = NULL; + return -ENOMEM; +} + +/*********************************************************/ +/* refcount handling */ + +static int refcount_init(BlockDriverState *bs) +{ + BDRVQcowState *s = bs->opaque; + int ret, refcount_table_size2, i; + + s->refcount_block_cache = qemu_malloc(s->cluster_size); + if (!s->refcount_block_cache) + goto fail; + refcount_table_size2 = s->refcount_table_size * sizeof(uint64_t); + s->refcount_table = qemu_malloc(refcount_table_size2); + if (!s->refcount_table) + goto fail; + if (s->refcount_table_size > 0) { + ret = bdrv_pread(s->hd, s->refcount_table_offset, + s->refcount_table, refcount_table_size2); + if (ret != refcount_table_size2) + goto fail; + for(i = 0; i < s->refcount_table_size; i++) + be64_to_cpus(&s->refcount_table[i]); + } + return 0; + fail: + return -ENOMEM; +} + +static void refcount_close(BlockDriverState *bs) +{ + BDRVQcowState *s = bs->opaque; + qemu_free(s->refcount_block_cache); + qemu_free(s->refcount_table); +} + + +static int load_refcount_block(BlockDriverState *bs, + int64_t refcount_block_offset) +{ + BDRVQcowState *s = bs->opaque; + int ret; + ret = bdrv_pread(s->hd, refcount_block_offset, s->refcount_block_cache, + s->cluster_size); + if (ret != s->cluster_size) + return -EIO; + s->refcount_block_cache_offset = refcount_block_offset; + return 0; +} + +static int get_refcount(BlockDriverState *bs, int64_t cluster_index) +{ + BDRVQcowState *s = bs->opaque; + int refcount_table_index, block_index; + int64_t refcount_block_offset; + + refcount_table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT); + if (refcount_table_index >= s->refcount_table_size) + return 0; + refcount_block_offset = s->refcount_table[refcount_table_index]; + if (!refcount_block_offset) + return 0; + if (refcount_block_offset != s->refcount_block_cache_offset) { + /* better than nothing: return allocated if read error */ + if (load_refcount_block(bs, refcount_block_offset) < 0) + return 1; + } + block_index = cluster_index & + ((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1); + return be16_to_cpu(s->refcount_block_cache[block_index]); +} + +/* return < 0 if error */ +static int64_t alloc_clusters_noref(BlockDriverState *bs, int64_t size) +{ + BDRVQcowState *s = bs->opaque; + int i, nb_clusters; + + nb_clusters = (size + s->cluster_size - 1) >> s->cluster_bits; + for(;;) { + if (get_refcount(bs, s->free_cluster_index) == 0) { + s->free_cluster_index++; + for(i = 1; i < nb_clusters; i++) { + if (get_refcount(bs, s->free_cluster_index) != 0) + goto not_found; + s->free_cluster_index++; + } +#ifdef DEBUG_ALLOC2 + printf("alloc_clusters: size=%lld -> %lld\n", + size, + (s->free_cluster_index - nb_clusters) << s->cluster_bits); +#endif + return (s->free_cluster_index - nb_clusters) << s->cluster_bits; + } else { + not_found: + s->free_cluster_index++; + } + } +} + +static int64_t alloc_clusters(BlockDriverState *bs, int64_t size) +{ + int64_t offset; + + offset = alloc_clusters_noref(bs, size); + update_refcount(bs, offset, size, 1); + return offset; +} + +/* only used to allocate compressed sectors. We try to allocate + contiguous sectors. size must be <= cluster_size */ +static int64_t alloc_bytes(BlockDriverState *bs, int size) +{ + BDRVQcowState *s = bs->opaque; + int64_t offset, cluster_offset; + int free_in_cluster; + + assert(size > 0 && size <= s->cluster_size); + if (s->free_byte_offset == 0) { + s->free_byte_offset = alloc_clusters(bs, s->cluster_size); + } + redo: + free_in_cluster = s->cluster_size - + (s->free_byte_offset & (s->cluster_size - 1)); + if (size <= free_in_cluster) { + /* enough space in current cluster */ + offset = s->free_byte_offset; + s->free_byte_offset += size; + free_in_cluster -= size; + if (free_in_cluster == 0) + s->free_byte_offset = 0; + if ((offset & (s->cluster_size - 1)) != 0) + update_cluster_refcount(bs, offset >> s->cluster_bits, 1); + } else { + offset = alloc_clusters(bs, s->cluster_size); + cluster_offset = s->free_byte_offset & ~(s->cluster_size - 1); + if ((cluster_offset + s->cluster_size) == offset) { + /* we are lucky: contiguous data */ + offset = s->free_byte_offset; + update_cluster_refcount(bs, offset >> s->cluster_bits, 1); + s->free_byte_offset += size; + } else { + s->free_byte_offset = offset; + goto redo; + } + } + return offset; +} + +static void free_clusters(BlockDriverState *bs, + int64_t offset, int64_t size) +{ + update_refcount(bs, offset, size, -1); +} + +static int grow_refcount_table(BlockDriverState *bs, int min_size) +{ + BDRVQcowState *s = bs->opaque; + int new_table_size, new_table_size2, refcount_table_clusters, i, ret; + uint64_t *new_table; + int64_t table_offset; + uint64_t data64; + uint32_t data32; + + if (min_size <= s->refcount_table_size) + return 0; + /* compute new table size */ + refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3); + for(;;) { + if (refcount_table_clusters == 0) { + refcount_table_clusters = 1; + } else { + refcount_table_clusters = (refcount_table_clusters * 3 + 1) / 2; + } + new_table_size = refcount_table_clusters << (s->cluster_bits - 3); + if (min_size <= new_table_size) + break; + } + + new_table_size2 = new_table_size * sizeof(uint64_t); + new_table = qemu_mallocz(new_table_size2); + if (!new_table) + return -ENOMEM; + memcpy(new_table, s->refcount_table, + s->refcount_table_size * sizeof(uint64_t)); + for(i = 0; i < s->refcount_table_size; i++) + cpu_to_be64s(&new_table[i]); + /* Note: we cannot update the refcount now to avoid recursion */ + table_offset = alloc_clusters_noref(bs, new_table_size2); + ret = bdrv_pwrite(s->hd, table_offset, new_table, new_table_size2); + if (ret != new_table_size2) + goto fail; + for(i = 0; i < s->refcount_table_size; i++) + be64_to_cpus(&new_table[i]); + + data64 = cpu_to_be64(table_offset); + if (bdrv_pwrite(s->hd, offsetof(QCowHeader, refcount_table_offset), + &data64, sizeof(data64)) != sizeof(data64)) + goto fail; + data32 = cpu_to_be32(refcount_table_clusters); + if (bdrv_pwrite(s->hd, offsetof(QCowHeader, refcount_table_clusters), + &data32, sizeof(data32)) != sizeof(data32)) + goto fail; + qemu_free(s->refcount_table); + s->refcount_table = new_table; + s->refcount_table_size = new_table_size; + + update_refcount(bs, table_offset, new_table_size2, 1); + return 0; + fail: + free_clusters(bs, table_offset, new_table_size2); + qemu_free(new_table); + return -EIO; +} + +/* addend must be 1 or -1 */ +/* XXX: cache several refcount block clusters ? */ +static int update_cluster_refcount(BlockDriverState *bs, + int64_t cluster_index, + int addend) +{ + BDRVQcowState *s = bs->opaque; + int64_t offset, refcount_block_offset; + int ret, refcount_table_index, block_index, refcount; + uint64_t data64; + + refcount_table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT); + if (refcount_table_index >= s->refcount_table_size) { + if (addend < 0) + return -EINVAL; + ret = grow_refcount_table(bs, refcount_table_index + 1); + if (ret < 0) + return ret; + } + refcount_block_offset = s->refcount_table[refcount_table_index]; + if (!refcount_block_offset) { + if (addend < 0) + return -EINVAL; + /* create a new refcount block */ + /* Note: we cannot update the refcount now to avoid recursion */ + offset = alloc_clusters_noref(bs, s->cluster_size); + memset(s->refcount_block_cache, 0, s->cluster_size); + ret = bdrv_pwrite(s->hd, offset, s->refcount_block_cache, s->cluster_size); + if (ret != s->cluster_size) + return -EINVAL; + s->refcount_table[refcount_table_index] = offset; + data64 = cpu_to_be64(offset); + ret = bdrv_pwrite(s->hd, s->refcount_table_offset + + refcount_table_index * sizeof(uint64_t), + &data64, sizeof(data64)); + if (ret != sizeof(data64)) + return -EINVAL; + + refcount_block_offset = offset; + s->refcount_block_cache_offset = offset; + update_refcount(bs, offset, s->cluster_size, 1); + } else { + if (refcount_block_offset != s->refcount_block_cache_offset) { + if (load_refcount_block(bs, refcount_block_offset) < 0) + return -EIO; + } + } + /* we can update the count and save it */ + block_index = cluster_index & + ((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1); + refcount = be16_to_cpu(s->refcount_block_cache[block_index]); + refcount += addend; + if (refcount < 0 || refcount > 0xffff) + return -EINVAL; + if (refcount == 0 && cluster_index < s->free_cluster_index) { + s->free_cluster_index = cluster_index; + } + s->refcount_block_cache[block_index] = cpu_to_be16(refcount); + if (bdrv_pwrite(s->hd, + refcount_block_offset + (block_index << REFCOUNT_SHIFT), + &s->refcount_block_cache[block_index], 2) != 2) + return -EIO; + return refcount; +} + +static void update_refcount(BlockDriverState *bs, + int64_t offset, int64_t length, + int addend) +{ + BDRVQcowState *s = bs->opaque; + int64_t start, last, cluster_offset; + +#ifdef DEBUG_ALLOC2 + printf("update_refcount: offset=%lld size=%lld addend=%d\n", + offset, length, addend); +#endif + if (length <= 0) + return; + start = offset & ~(s->cluster_size - 1); + last = (offset + length - 1) & ~(s->cluster_size - 1); + for(cluster_offset = start; cluster_offset <= last; + cluster_offset += s->cluster_size) { + update_cluster_refcount(bs, cluster_offset >> s->cluster_bits, addend); + } +} + +#ifdef DEBUG_ALLOC +static void inc_refcounts(BlockDriverState *bs, + uint16_t *refcount_table, + int refcount_table_size, + int64_t offset, int64_t size) +{ + BDRVQcowState *s = bs->opaque; + int64_t start, last, cluster_offset; + int k; + + if (size <= 0) + return; + + start = offset & ~(s->cluster_size - 1); + last = (offset + size - 1) & ~(s->cluster_size - 1); + for(cluster_offset = start; cluster_offset <= last; + cluster_offset += s->cluster_size) { + k = cluster_offset >> s->cluster_bits; + if (k < 0 || k >= refcount_table_size) { + printf("ERROR: invalid cluster offset=0x%llx\n", cluster_offset); + } else { + if (++refcount_table[k] == 0) { + printf("ERROR: overflow cluster offset=0x%llx\n", cluster_offset); + } + } + } +} + +static int check_refcounts_l1(BlockDriverState *bs, + uint16_t *refcount_table, + int refcount_table_size, + int64_t l1_table_offset, int l1_size, + int check_copied) +{ + BDRVQcowState *s = bs->opaque; + uint64_t *l1_table, *l2_table, l2_offset, offset, l1_size2; + int l2_size, i, j, nb_csectors, refcount; + + l2_table = NULL; + l1_size2 = l1_size * sizeof(uint64_t); + + inc_refcounts(bs, refcount_table, refcount_table_size, + l1_table_offset, l1_size2); + + l1_table = qemu_malloc(l1_size2); + if (!l1_table) + goto fail; + if (bdrv_pread(s->hd, l1_table_offset, + l1_table, l1_size2) != l1_size2) + goto fail; + for(i = 0;i < l1_size; i++) + be64_to_cpus(&l1_table[i]); + + l2_size = s->l2_size * sizeof(uint64_t); + l2_table = qemu_malloc(l2_size); + if (!l2_table) + goto fail; + for(i = 0; i < l1_size; i++) { + l2_offset = l1_table[i]; + if (l2_offset) { + if (check_copied) { + refcount = get_refcount(bs, (l2_offset & ~QCOW_OFLAG_COPIED) >> s->cluster_bits); + if ((refcount == 1) != ((l2_offset & QCOW_OFLAG_COPIED) != 0)) { + printf("ERROR OFLAG_COPIED: l2_offset=%llx refcount=%d\n", + l2_offset, refcount); + } + } + l2_offset &= ~QCOW_OFLAG_COPIED; + if (bdrv_pread(s->hd, l2_offset, l2_table, l2_size) != l2_size) + goto fail; + for(j = 0; j < s->l2_size; j++) { + offset = be64_to_cpu(l2_table[j]); + if (offset != 0) { + if (offset & QCOW_OFLAG_COMPRESSED) { + if (offset & QCOW_OFLAG_COPIED) { + printf("ERROR: cluster %lld: copied flag must never be set for compressed clusters\n", + offset >> s->cluster_bits); + offset &= ~QCOW_OFLAG_COPIED; + } + nb_csectors = ((offset >> s->csize_shift) & + s->csize_mask) + 1; + offset &= s->cluster_offset_mask; + inc_refcounts(bs, refcount_table, + refcount_table_size, + offset & ~511, nb_csectors * 512); + } else { + if (check_copied) { + refcount = get_refcount(bs, (offset & ~QCOW_OFLAG_COPIED) >> s->cluster_bits); + if ((refcount == 1) != ((offset & QCOW_OFLAG_COPIED) != 0)) { + printf("ERROR OFLAG_COPIED: offset=%llx refcount=%d\n", + offset, refcount); + } + } + offset &= ~QCOW_OFLAG_COPIED; + inc_refcounts(bs, refcount_table, + refcount_table_size, + offset, s->cluster_size); + } + } + } + inc_refcounts(bs, refcount_table, + refcount_table_size, + l2_offset, + s->cluster_size); + } + } + qemu_free(l1_table); + qemu_free(l2_table); + return 0; + fail: + printf("ERROR: I/O error in check_refcounts_l1\n"); + qemu_free(l1_table); + qemu_free(l2_table); + return -EIO; +} + +static void check_refcounts(BlockDriverState *bs) +{ + BDRVQcowState *s = bs->opaque; + int64_t size; + int nb_clusters, refcount1, refcount2, i; + QCowSnapshot *sn; + uint16_t *refcount_table; + + size = bdrv_getlength(s->hd); + nb_clusters = (size + s->cluster_size - 1) >> s->cluster_bits; + refcount_table = qemu_mallocz(nb_clusters * sizeof(uint16_t)); + + /* header */ + inc_refcounts(bs, refcount_table, nb_clusters, + 0, s->cluster_size); + + check_refcounts_l1(bs, refcount_table, nb_clusters, + s->l1_table_offset, s->l1_size, 1); + + /* snapshots */ + for(i = 0; i < s->nb_snapshots; i++) { + sn = s->snapshots + i; + check_refcounts_l1(bs, refcount_table, nb_clusters, + sn->l1_table_offset, sn->l1_size, 0); + } + inc_refcounts(bs, refcount_table, nb_clusters, + s->snapshots_offset, s->snapshots_size); + + /* refcount data */ + inc_refcounts(bs, refcount_table, nb_clusters, + s->refcount_table_offset, + s->refcount_table_size * sizeof(uint64_t)); + for(i = 0; i < s->refcount_table_size; i++) { + int64_t offset; + offset = s->refcount_table[i]; + if (offset != 0) { + inc_refcounts(bs, refcount_table, nb_clusters, + offset, s->cluster_size); + } + } + + /* compare ref counts */ + for(i = 0; i < nb_clusters; i++) { + refcount1 = get_refcount(bs, i); + refcount2 = refcount_table[i]; + if (refcount1 != refcount2) + printf("ERROR cluster %d refcount=%d reference=%d\n", + i, refcount1, refcount2); + } + + qemu_free(refcount_table); +} + +#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 + s->cluster_size - 1) >> s->cluster_bits; + 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 +#endif + +BlockDriver bdrv_qcow2 = { + "qcow2", + sizeof(BDRVQcowState), + qcow_probe, + qcow_open, + NULL, + NULL, + qcow_close, + qcow_create, + qcow_flush, + qcow_is_allocated, + qcow_set_key, + qcow_make_empty, + + .bdrv_aio_new = qcow_aio_new, + .bdrv_aio_read = qcow_aio_read, + .bdrv_aio_write = qcow_aio_write, + .bdrv_aio_cancel = qcow_aio_cancel, + .bdrv_aio_delete = qcow_aio_delete, + .bdrv_write_compressed = qcow_write_compressed, + + .bdrv_snapshot_create = qcow_snapshot_create, + .bdrv_snapshot_goto = qcow_snapshot_goto, + .bdrv_snapshot_delete = qcow_snapshot_delete, + .bdrv_snapshot_list = qcow_snapshot_list, + .bdrv_get_info = qcow_get_info, +}; 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