diff options
Diffstat (limited to 'block/qcow2.c')
| -rw-r--r-- | block/qcow2.c | 2931 |
1 files changed, 2931 insertions, 0 deletions
diff --git a/block/qcow2.c b/block/qcow2.c new file mode 100644 index 0000000000..a6de9b6919 --- /dev/null +++ b/block/qcow2.c @@ -0,0 +1,2931 @@ +/* + * 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" + +/* + 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 + +#define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb) +#define QCOW_VERSION 2 + +#define QCOW_CRYPT_NONE 0 +#define QCOW_CRYPT_AES 1 + +#define QCOW_MAX_CRYPT_CLUSTERS 32 + +/* 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 */ + +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 { + uint32_t magic; + uint32_t len; +} QCowExtension; +#define QCOW_EXT_MAGIC_END 0 +#define QCOW_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA + + +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); +static int check_refcounts(BlockDriverState *bs); + +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 < 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 (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 (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 (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; + uint8_t data[12]; + + 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); + 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 */ + cpu_to_be32w((uint32_t*)data, new_l1_size); + cpu_to_be64w((uint64_t*)(data + 4), new_l1_table_offset); + if (bdrv_pwrite(s->hd, offsetof(QCowHeader, l1_size), data, + sizeof(data)) != sizeof(data)) + 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; +} + +/* + * seek_l2_table + * + * seek l2_offset in the l2_cache table + * if not found, return NULL, + * if found, + * increments the l2 cache hit count of the entry, + * if counter overflow, divide by two all counters + * return the pointer to the l2 cache entry + * + */ + +static uint64_t *seek_l2_table(BDRVQcowState *s, uint64_t l2_offset) +{ + int i, j; + + 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; + } + } + return s->l2_cache + (i << s->l2_bits); + } + } + return NULL; +} + +/* + * l2_load + * + * Loads a L2 table into memory. If the table is in the cache, the cache + * is used; otherwise the L2 table is loaded from the image file. + * + * Returns a pointer to the L2 table on success, or NULL if the read from + * the image file failed. + */ + +static uint64_t *l2_load(BlockDriverState *bs, uint64_t l2_offset) +{ + BDRVQcowState *s = bs->opaque; + int min_index; + uint64_t *l2_table; + + /* seek if the table for the given offset is in the cache */ + + l2_table = seek_l2_table(s, l2_offset); + if (l2_table != NULL) + return l2_table; + + /* 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 NULL; + s->l2_cache_offsets[min_index] = l2_offset; + s->l2_cache_counts[min_index] = 1; + + return l2_table; +} + +/* + * l2_allocate + * + * Allocate a new l2 entry in the file. If l1_index points to an already + * used entry in the L2 table (i.e. we are doing a copy on write for the L2 + * table) copy the contents of the old L2 table into the newly allocated one. + * Otherwise the new table is initialized with zeros. + * + */ + +static uint64_t *l2_allocate(BlockDriverState *bs, int l1_index) +{ + BDRVQcowState *s = bs->opaque; + int min_index; + uint64_t old_l2_offset, tmp; + uint64_t *l2_table, l2_offset; + + old_l2_offset = s->l1_table[l1_index]; + + /* 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 NULL; + + /* allocate a new entry in the l2 cache */ + + min_index = l2_cache_new_entry(bs); + l2_table = s->l2_cache + (min_index << s->l2_bits); + + if (old_l2_offset == 0) { + /* if there was no old l2 table, clear the new table */ + memset(l2_table, 0, s->l2_size * sizeof(uint64_t)); + } else { + /* if there was an old l2 table, read it from the disk */ + if (bdrv_pread(s->hd, old_l2_offset, + l2_table, s->l2_size * sizeof(uint64_t)) != + s->l2_size * sizeof(uint64_t)) + return NULL; + } + /* write the l2 table to the file */ + if (bdrv_pwrite(s->hd, l2_offset, + l2_table, s->l2_size * sizeof(uint64_t)) != + s->l2_size * sizeof(uint64_t)) + return NULL; + + /* update the l2 cache entry */ + + s->l2_cache_offsets[min_index] = l2_offset; + s->l2_cache_counts[min_index] = 1; + + return l2_table; +} + +static int size_to_clusters(BDRVQcowState *s, int64_t size) +{ + return (size + (s->cluster_size - 1)) >> s->cluster_bits; +} + +static int count_contiguous_clusters(uint64_t nb_clusters, int cluster_size, + uint64_t *l2_table, uint64_t start, uint64_t mask) +{ + int i; + uint64_t offset = be64_to_cpu(l2_table[0]) & ~mask; + + if (!offset) + return 0; + + for (i = start; i < start + nb_clusters; i++) + if (offset + i * cluster_size != (be64_to_cpu(l2_table[i]) & ~mask)) + break; + + return (i - start); +} + +static int count_contiguous_free_clusters(uint64_t nb_clusters, uint64_t *l2_table) +{ + int i = 0; + + while(nb_clusters-- && l2_table[i] == 0) + i++; + + return i; +} + +/* + * get_cluster_offset + * + * For a given offset of the disk image, return cluster offset in + * qcow2 file. + * + * on entry, *num is the number of contiguous clusters we'd like to + * access following offset. + * + * on exit, *num is the number of contiguous clusters we can read. + * + * Return 1, if the offset is found + * Return 0, otherwise. + * + */ + +static uint64_t get_cluster_offset(BlockDriverState *bs, + uint64_t offset, int *num) +{ + BDRVQcowState *s = bs->opaque; + int l1_index, l2_index; + uint64_t l2_offset, *l2_table, cluster_offset; + int l1_bits, c; + int index_in_cluster, nb_available, nb_needed, nb_clusters; + + index_in_cluster = (offset >> 9) & (s->cluster_sectors - 1); + nb_needed = *num + index_in_cluster; + + l1_bits = s->l2_bits + s->cluster_bits; + + /* compute how many bytes there are between the offset and + * the end of the l1 entry + */ + + nb_available = (1 << l1_bits) - (offset & ((1 << l1_bits) - 1)); + + /* compute the number of available sectors */ + + nb_available = (nb_available >> 9) + index_in_cluster; + + if (nb_needed > nb_available) { + nb_needed = nb_available; + } + + cluster_offset = 0; + + /* seek the the l2 offset in the l1 table */ + + l1_index = offset >> l1_bits; + if (l1_index >= s->l1_size) + goto out; + + l2_offset = s->l1_table[l1_index]; + + /* seek the l2 table of the given l2 offset */ + + if (!l2_offset) + goto out; + + /* load the l2 table in memory */ + + l2_offset &= ~QCOW_OFLAG_COPIED; + l2_table = l2_load(bs, l2_offset); + if (l2_table == NULL) + return 0; + + /* find the cluster offset for the given disk offset */ + + l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1); + cluster_offset = be64_to_cpu(l2_table[l2_index]); + nb_clusters = size_to_clusters(s, nb_needed << 9); + + if (!cluster_offset) { + /* how many empty clusters ? */ + c = count_contiguous_free_clusters(nb_clusters, &l2_table[l2_index]); + } else { + /* how many allocated clusters ? */ + c = count_contiguous_clusters(nb_clusters, s->cluster_size, + &l2_table[l2_index], 0, QCOW_OFLAG_COPIED); + } + + nb_available = (c * s->cluster_sectors); +out: + if (nb_available > nb_needed) + nb_available = nb_needed; + + *num = nb_available - index_in_cluster; + + return cluster_offset & ~QCOW_OFLAG_COPIED; +} + +/* + * free_any_clusters + * + * free clusters according to its type: compressed or not + * + */ + +static void free_any_clusters(BlockDriverState *bs, + uint64_t cluster_offset, int nb_clusters) +{ + BDRVQcowState *s = bs->opaque; + + /* 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); + return; + } + + free_clusters(bs, cluster_offset, nb_clusters << s->cluster_bits); + + return; +} + +/* + * get_cluster_table + * + * for a given disk offset, load (and allocate if needed) + * the l2 table. + * + * the l2 table offset in the qcow2 file and the cluster index + * in the l2 table are given to the caller. + * + */ + +static int get_cluster_table(BlockDriverState *bs, uint64_t offset, + uint64_t **new_l2_table, + uint64_t *new_l2_offset, + int *new_l2_index) +{ + BDRVQcowState *s = bs->opaque; + int l1_index, l2_index, ret; + uint64_t l2_offset, *l2_table; + + /* seek the the l2 offset in the l1 table */ + + l1_index = offset >> (s->l2_bits + s->cluster_bits); + if (l1_index >= s->l1_size) { + ret = grow_l1_table(bs, l1_index + 1); + if (ret < 0) + return 0; + } + l2_offset = s->l1_table[l1_index]; + + /* seek the l2 table of the given l2 offset */ + + if (l2_offset & QCOW_OFLAG_COPIED) { + /* load the l2 table in memory */ + l2_offset &= ~QCOW_OFLAG_COPIED; + l2_table = l2_load(bs, l2_offset); + if (l2_table == NULL) + return 0; + } else { + if (l2_offset) + free_clusters(bs, l2_offset, s->l2_size * sizeof(uint64_t)); + l2_table = l2_allocate(bs, l1_index); + if (l2_table == NULL) + return 0; + l2_offset = s->l1_table[l1_index] & ~QCOW_OFLAG_COPIED; + } + + /* find the cluster offset for the given disk offset */ + + l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1); + + *new_l2_table = l2_table; + *new_l2_offset = l2_offset; + *new_l2_index = l2_index; + + return 1; +} + +/* + * alloc_compressed_cluster_offset + * + * For a given offset of the disk image, return cluster offset in + * qcow2 file. + * + * If the offset is not found, allocate a new compressed cluster. + * + * Return the cluster offset if successful, + * Return 0, otherwise. + * + */ + +static uint64_t alloc_compressed_cluster_offset(BlockDriverState *bs, + uint64_t offset, + int compressed_size) +{ + BDRVQcowState *s = bs->opaque; + int l2_index, ret; + uint64_t l2_offset, *l2_table, cluster_offset; + int nb_csectors; + + ret = get_cluster_table(bs, offset, &l2_table, &l2_offset, &l2_index); + if (ret == 0) + return 0; + + cluster_offset = be64_to_cpu(l2_table[l2_index]); + if (cluster_offset & QCOW_OFLAG_COPIED) + return cluster_offset & ~QCOW_OFLAG_COPIED; + + if (cluster_offset) + free_any_clusters(bs, cluster_offset, 1); + + 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); + + /* update L2 table */ + + /* compressed clusters never have the copied flag */ + + l2_table[l2_index] = cpu_to_be64(cluster_offset); + if (bdrv_pwrite(s->hd, + l2_offset + l2_index * sizeof(uint64_t), + l2_table + l2_index, + sizeof(uint64_t)) != sizeof(uint64_t)) + return 0; + + return cluster_offset; +} + +typedef struct QCowL2Meta +{ + uint64_t offset; + int n_start; + int nb_available; + int nb_clusters; +} QCowL2Meta; + +static int alloc_cluster_link_l2(BlockDriverState *bs, uint64_t cluster_offset, + QCowL2Meta *m) +{ + BDRVQcowState *s = bs->opaque; + int i, j = 0, l2_index, ret; + uint64_t *old_cluster, start_sect, l2_offset, *l2_table; + + if (m->nb_clusters == 0) + return 0; + + old_cluster = qemu_malloc(m->nb_clusters * sizeof(uint64_t)); + + /* copy content of unmodified sectors */ + start_sect = (m->offset & ~(s->cluster_size - 1)) >> 9; + if (m->n_start) { + ret = copy_sectors(bs, start_sect, cluster_offset, 0, m->n_start); + if (ret < 0) + goto err; + } + + if (m->nb_available & (s->cluster_sectors - 1)) { + uint64_t end = m->nb_available & ~(uint64_t)(s->cluster_sectors - 1); + ret = copy_sectors(bs, start_sect + end, cluster_offset + (end << 9), + m->nb_available - end, s->cluster_sectors); + if (ret < 0) + goto err; + } + + ret = -EIO; + /* update L2 table */ + if (!get_cluster_table(bs, m->offset, &l2_table, &l2_offset, &l2_index)) + goto err; + + for (i = 0; i < m->nb_clusters; i++) { + /* if two concurrent writes happen to the same unallocated cluster + * each write allocates separate cluster and writes data concurrently. + * The first one to complete updates l2 table with pointer to its + * cluster the second one has to do RMW (which is done above by + * copy_sectors()), update l2 table with its cluster pointer and free + * old cluster. This is what this loop does */ + if(l2_table[l2_index + i] != 0) + old_cluster[j++] = l2_table[l2_index + i]; + + l2_table[l2_index + i] = cpu_to_be64((cluster_offset + + (i << s->cluster_bits)) | QCOW_OFLAG_COPIED); + } + + if (bdrv_pwrite(s->hd, l2_offset + l2_index * sizeof(uint64_t), + l2_table + l2_index, m->nb_clusters * sizeof(uint64_t)) != + m->nb_clusters * sizeof(uint64_t)) + goto err; + + for (i = 0; i < j; i++) + free_any_clusters(bs, be64_to_cpu(old_cluster[i]) & ~QCOW_OFLAG_COPIED, + 1); + + ret = 0; +err: + qemu_free(old_cluster); + return ret; + } + +/* + * alloc_cluster_offset + * + * For a given offset of the disk image, return cluster offset in + * qcow2 file. + * + * If the offset is not found, allocate a new cluster. + * + * Return the cluster offset if successful, + * Return 0, otherwise. + * + */ + +static uint64_t alloc_cluster_offset(BlockDriverState *bs, + uint64_t offset, + int n_start, int n_end, + int *num, QCowL2Meta *m) +{ + BDRVQcowState *s = bs->opaque; + int l2_index, ret; + uint64_t l2_offset, *l2_table, cluster_offset; + int nb_clusters, i = 0; + + ret = get_cluster_table(bs, offset, &l2_table, &l2_offset, &l2_index); + if (ret == 0) + return 0; + + nb_clusters = size_to_clusters(s, n_end << 9); + + nb_clusters = MIN(nb_clusters, s->l2_size - l2_index); + + cluster_offset = be64_to_cpu(l2_table[l2_index]); + + /* We keep all QCOW_OFLAG_COPIED clusters */ + + if (cluster_offset & QCOW_OFLAG_COPIED) { + nb_clusters = count_contiguous_clusters(nb_clusters, s->cluster_size, + &l2_table[l2_index], 0, 0); + + cluster_offset &= ~QCOW_OFLAG_COPIED; + m->nb_clusters = 0; + + goto out; + } + + /* for the moment, multiple compressed clusters are not managed */ + + if (cluster_offset & QCOW_OFLAG_COMPRESSED) + nb_clusters = 1; + + /* how many available clusters ? */ + + while (i < nb_clusters) { + i += count_contiguous_clusters(nb_clusters - i, s->cluster_size, + &l2_table[l2_index], i, 0); + + if(be64_to_cpu(l2_table[l2_index + i])) + break; + + i += count_contiguous_free_clusters(nb_clusters - i, + &l2_table[l2_index + i]); + + cluster_offset = be64_to_cpu(l2_table[l2_index + i]); + + if ((cluster_offset & QCOW_OFLAG_COPIED) || + (cluster_offset & QCOW_OFLAG_COMPRESSED)) + break; + } + nb_clusters = i; + + /* allocate a new cluster */ + + cluster_offset = alloc_clusters(bs, nb_clusters * s->cluster_size); + + /* save info needed for meta data update */ + m->offset = offset; + m->n_start = n_start; + m->nb_clusters = nb_clusters; + +out: + m->nb_available = MIN(nb_clusters << (s->cluster_bits - 9), n_end); + + *num = m->nb_available - n_start; + + return cluster_offset; +} + +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 = get_cluster_offset(bs, sector_num << 9, pnum); + + 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; +} + +/* handle reading after the end of the backing file */ +static int 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; +} + +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, n1; + uint64_t cluster_offset; + + while (nb_sectors > 0) { + n = nb_sectors; + cluster_offset = get_cluster_offset(bs, sector_num << 9, &n); + index_in_cluster = sector_num & (s->cluster_sectors - 1); + if (!cluster_offset) { + if (bs->backing_hd) { + /* read from the base image */ + n1 = backing_read1(bs->backing_hd, sector_num, buf, n); + if (n1 > 0) { + ret = bdrv_read(bs->backing_hd, sector_num, buf, n1); + 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; + int n_end; + QCowL2Meta l2meta; + + while (nb_sectors > 0) { + index_in_cluster = sector_num & (s->cluster_sectors - 1); + n_end = index_in_cluster + nb_sectors; + if (s->crypt_method && + n_end > QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors) + n_end = QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors; + cluster_offset = alloc_cluster_offset(bs, sector_num << 9, + index_in_cluster, + n_end, &n, &l2meta); + 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 || alloc_cluster_link_l2(bs, cluster_offset, &l2meta) < 0) { + free_any_clusters(bs, cluster_offset, l2meta.nb_clusters); + return -1; + } + nb_sectors -= n; + sector_num += n; + buf += n * 512; + } + s->cluster_cache_offset = -1; /* disable compressed cache */ + return 0; +} + +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_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) { + 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 = 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 = 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 (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(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 (alloc_cluster_link_l2(bs, acb->cluster_offset, &acb->l2meta) < 0) { + 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 = 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); + } + 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_aio_cancel(BlockDriverAIOCB *blockacb) +{ + QCowAIOCB *acb = (QCowAIOCB *)blockacb; + if (acb->hd_aiocb) + bdrv_aio_cancel(acb->hd_aiocb); + qemu_aio_release(acb); +} + +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_create2(const char *filename, int64_t total_size, + const char *backing_file, const char *backing_format, + int flags) +{ + + 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; + } + 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 & 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 */ + create_refcount_update(s, 0, header_size); + create_refcount_update(s, s->l1_table_offset, l1_size * sizeof(uint64_t)); + create_refcount_update(s, s->refcount_table_offset, s->cluster_size); + 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, int64_t total_size, + const char *backing_file, int flags) +{ + return qcow_create2(filename, total_size, backing_file, NULL, flags); +} + +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 */ + qcow_write(bs, sector_num, buf, s->cluster_sectors); + } else { + cluster_offset = 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; +} + +/*********************************************************/ +/* 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); + 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); + 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; + + if (!s->nb_snapshots) { + s->snapshots = NULL; + s->snapshots_size = 0; + return 0; + } + + offset = s->snapshots_offset; + s->snapshots = qemu_mallocz(s->nb_snapshots * sizeof(QCowSnapshot)); + 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 (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 (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)); + 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 (s->snapshots) { + memcpy(snapshots1, s->snapshots, s->nb_snapshots * sizeof(QCowSnapshot)); + qemu_free(s->snapshots); + } + 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)); + 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; +} + +/*********************************************************/ +/* 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); + refcount_table_size2 = s->refcount_table_size * sizeof(uint64_t); + s->refcount_table = qemu_malloc(refcount_table_size2); + 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_to_clusters(s, size); +retry: + for(i = 0; i < nb_clusters; i++) { + int64_t i = s->free_cluster_index++; + if (get_refcount(bs, i) != 0) + goto retry; + } +#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; +} + +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; + uint8_t data[12]; + int old_table_size; + int64_t old_table_offset; + + 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; + } +#ifdef DEBUG_ALLOC2 + printf("grow_refcount_table from %d to %d\n", + s->refcount_table_size, + new_table_size); +#endif + new_table_size2 = new_table_size * sizeof(uint64_t); + new_table = qemu_mallocz(new_table_size2); + 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]); + + cpu_to_be64w((uint64_t*)data, table_offset); + cpu_to_be32w((uint32_t*)(data + 8), refcount_table_clusters); + if (bdrv_pwrite(s->hd, offsetof(QCowHeader, refcount_table_offset), + data, sizeof(data)) != sizeof(data)) + goto fail; + qemu_free(s->refcount_table); + old_table_offset = s->refcount_table_offset; + old_table_size = s->refcount_table_size; + s->refcount_table = new_table; + s->refcount_table_size = new_table_size; + s->refcount_table_offset = table_offset; + + update_refcount(bs, table_offset, new_table_size2, 1); + free_clusters(bs, old_table_offset, old_table_size * sizeof(uint64_t)); + 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); + } +} + +/* + * Increases the refcount for a range of clusters in a given refcount table. + * This is used to construct a temporary refcount table out of L1 and L2 tables + * which can be compared the the refcount table saved in the image. + * + * Returns the number of errors in the image that were found + */ +static int 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; + int errors = 0; + + if (size <= 0) + return 0; + + 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) { + fprintf(stderr, "ERROR: invalid cluster offset=0x%" PRIx64 "\n", + cluster_offset); + errors++; + } else { + if (++refcount_table[k] == 0) { + fprintf(stderr, "ERROR: overflow cluster offset=0x%" PRIx64 + "\n", cluster_offset); + errors++; + } + } + } + + return errors; +} + +/* + * Increases the refcount in the given refcount table for the all clusters + * referenced in the L2 table. While doing so, performs some checks on L2 + * entries. + * + * Returns the number of errors found by the checks or -errno if an internal + * error occurred. + */ +static int check_refcounts_l2(BlockDriverState *bs, + uint16_t *refcount_table, int refcount_table_size, int64_t l2_offset, + int check_copied) +{ + BDRVQcowState *s = bs->opaque; + uint64_t *l2_table, offset; + int i, l2_size, nb_csectors, refcount; + int errors = 0; + + /* Read L2 table from disk */ + l2_size = s->l2_size * sizeof(uint64_t); + l2_table = qemu_malloc(l2_size); + + if (bdrv_pread(s->hd, l2_offset, l2_table, l2_size) != l2_size) + goto fail; + + /* Do the actual checks */ + for(i = 0; i < s->l2_size; i++) { + offset = be64_to_cpu(l2_table[i]); + if (offset != 0) { + if (offset & QCOW_OFLAG_COMPRESSED) { + /* Compressed clusters don't have QCOW_OFLAG_COPIED */ + if (offset & QCOW_OFLAG_COPIED) { + fprintf(stderr, "ERROR: cluster %" PRId64 ": " + "copied flag must never be set for compressed " + "clusters\n", offset >> s->cluster_bits); + offset &= ~QCOW_OFLAG_COPIED; + errors++; + } + + /* Mark cluster as used */ + nb_csectors = ((offset >> s->csize_shift) & + s->csize_mask) + 1; + offset &= s->cluster_offset_mask; + errors += inc_refcounts(bs, refcount_table, + refcount_table_size, + offset & ~511, nb_csectors * 512); + } else { + /* QCOW_OFLAG_COPIED must be set iff refcount == 1 */ + if (check_copied) { + uint64_t entry = offset; + offset &= ~QCOW_OFLAG_COPIED; + refcount = get_refcount(bs, offset >> s->cluster_bits); + if ((refcount == 1) != ((entry & QCOW_OFLAG_COPIED) != 0)) { + fprintf(stderr, "ERROR OFLAG_COPIED: offset=%" + PRIx64 " refcount=%d\n", entry, refcount); + errors++; + } + } + + /* Mark cluster as used */ + offset &= ~QCOW_OFLAG_COPIED; + errors += inc_refcounts(bs, refcount_table, + refcount_table_size, + offset, s->cluster_size); + + /* Correct offsets are cluster aligned */ + if (offset & (s->cluster_size - 1)) { + fprintf(stderr, "ERROR offset=%" PRIx64 ": Cluster is not " + "properly aligned; L2 entry corrupted.\n", offset); + errors++; + } + } + } + } + + qemu_free(l2_table); + return errors; + +fail: + fprintf(stderr, "ERROR: I/O error in check_refcounts_l1\n"); + qemu_free(l2_table); + return -EIO; +} + +/* + * Increases the refcount for the L1 table, its L2 tables and all referenced + * clusters in the given refcount table. While doing so, performs some checks + * on L1 and L2 entries. + * + * Returns the number of errors found by the checks or -errno if an internal + * error occurred. + */ +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_offset, l1_size2; + int i, refcount, ret; + int errors = 0; + + l1_size2 = l1_size * sizeof(uint64_t); + + /* Mark L1 table as used */ + errors += inc_refcounts(bs, refcount_table, refcount_table_size, + l1_table_offset, l1_size2); + + /* Read L1 table entries from disk */ + l1_table = qemu_malloc(l1_size2); + 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]); + + /* Do the actual checks */ + for(i = 0; i < l1_size; i++) { + l2_offset = l1_table[i]; + if (l2_offset) { + /* QCOW_OFLAG_COPIED must be set iff refcount == 1 */ + if (check_copied) { + refcount = get_refcount(bs, (l2_offset & ~QCOW_OFLAG_COPIED) + >> s->cluster_bits); + if ((refcount == 1) != ((l2_offset & QCOW_OFLAG_COPIED) != 0)) { + fprintf(stderr, "ERROR OFLAG_COPIED: l2_offset=%" PRIx64 + " refcount=%d\n", l2_offset, refcount); + errors++; + } + } + + /* Mark L2 table as used */ + l2_offset &= ~QCOW_OFLAG_COPIED; + errors += inc_refcounts(bs, refcount_table, + refcount_table_size, + l2_offset, + s->cluster_size); + + /* L2 tables are cluster aligned */ + if (l2_offset & (s->cluster_size - 1)) { + fprintf(stderr, "ERROR l2_offset=%" PRIx64 ": Table is not " + "cluster aligned; L1 entry corrupted\n", l2_offset); + errors++; + } + + /* Process and check L2 entries */ + ret = check_refcounts_l2(bs, refcount_table, refcount_table_size, + l2_offset, check_copied); + if (ret < 0) { + goto fail; + } + errors += ret; + } + } + qemu_free(l1_table); + return errors; + +fail: + fprintf(stderr, "ERROR: I/O error in check_refcounts_l1\n"); + qemu_free(l1_table); + return -EIO; +} + +/* + * Checks an image for refcount consistency. + * + * Returns 0 if no errors are found, the number of errors in case the image is + * detected as corrupted, and -errno when an internal error occured. + */ +static int check_refcounts(BlockDriverState *bs) +{ + BDRVQcowState *s = bs->opaque; + int64_t size; + int nb_clusters, refcount1, refcount2, i; + QCowSnapshot *sn; + uint16_t *refcount_table; + int ret, errors = 0; + + size = bdrv_getlength(s->hd); + nb_clusters = size_to_clusters(s, size); + refcount_table = qemu_mallocz(nb_clusters * sizeof(uint16_t)); + + /* header */ + errors += inc_refcounts(bs, refcount_table, nb_clusters, + 0, s->cluster_size); + + /* current L1 table */ + ret = check_refcounts_l1(bs, refcount_table, nb_clusters, + s->l1_table_offset, s->l1_size, 1); + if (ret < 0) { + return ret; + } + errors += ret; + + /* 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); + } + errors += inc_refcounts(bs, refcount_table, nb_clusters, + s->snapshots_offset, s->snapshots_size); + + /* refcount data */ + errors += 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) { + errors += 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) { + fprintf(stderr, "ERROR cluster %d refcount=%d reference=%d\n", + i, refcount1, refcount2); + errors++; + } + } + + qemu_free(refcount_table); + + return errors; +} + +static int qcow_check(BlockDriverState *bs) +{ + return 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 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_aio_cancel = qcow_aio_cancel, + .aiocb_size = sizeof(QCowAIOCB), + .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, + + .bdrv_put_buffer = qcow_put_buffer, + .bdrv_get_buffer = qcow_get_buffer, + + .bdrv_create2 = qcow_create2, + .bdrv_check = qcow_check, +}; + +static void bdrv_qcow2_init(void) +{ + bdrv_register(&bdrv_qcow2); +} + +block_init(bdrv_qcow2_init); |