diff options
Diffstat (limited to 'block/qcow2.c')
| -rw-r--r-- | block/qcow2.c | 2083 |
1 files changed, 32 insertions, 2051 deletions
diff --git a/block/qcow2.c b/block/qcow2.c index c2be42ed3..9acbddf94 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -26,6 +26,7 @@ #include "module.h" #include <zlib.h> #include "aes.h" +#include "block/qcow2.h" /* Differences with QCOW: @@ -47,40 +48,6 @@ //#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 */ - -#define MIN_CLUSTER_BITS 9 -#define MAX_CLUSTER_BITS 16 - -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; @@ -90,97 +57,6 @@ typedef struct { #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 int 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) { @@ -351,7 +227,7 @@ static int qcow_open(BlockDriverState *bs, const char *filename, int flags) + 512); s->cluster_cache_offset = -1; - if (refcount_init(bs) < 0) + if (qcow2_refcount_init(bs) < 0) goto fail; /* read qcow2 extensions */ @@ -371,7 +247,7 @@ static int qcow_open(BlockDriverState *bs, const char *filename, int flags) goto fail; bs->backing_file[len] = '\0'; } - if (qcow_read_snapshots(bs) < 0) + if (qcow2_read_snapshots(bs) < 0) goto fail; #ifdef DEBUG_ALLOC @@ -380,8 +256,8 @@ static int qcow_open(BlockDriverState *bs, const char *filename, int flags) return 0; fail: - qcow_free_snapshots(bs); - refcount_close(bs); + qcow2_free_snapshots(bs); + qcow2_refcount_close(bs); qemu_free(s->l1_table); qemu_free(s->l2_cache); qemu_free(s->cluster_cache); @@ -432,748 +308,20 @@ static int qcow_set_key(BlockDriverState *bs, const char *key) 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); + cluster_offset = qcow2_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 qcow2_backing_read1(BlockDriverState *bs, + int64_t sector_num, uint8_t *buf, int nb_sectors) { int n1; if ((sector_num + nb_sectors) <= bs->total_sectors) @@ -1186,49 +334,6 @@ static int backing_read1(BlockDriverState *bs, 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; -} - typedef struct QCowAIOCB { BlockDriverAIOCB common; int64_t sector_num; @@ -1300,7 +405,7 @@ static void qcow_aio_read_cb(void *opaque, int ret) /* nothing to do */ } else { if (s->crypt_method) { - encrypt_sectors(s, acb->sector_num, acb->buf, acb->buf, + qcow2_encrypt_sectors(s, acb->sector_num, acb->buf, acb->buf, acb->n, 0, &s->aes_decrypt_key); } @@ -1318,13 +423,14 @@ static void qcow_aio_read_cb(void *opaque, int ret) /* prepare next AIO request */ acb->n = acb->nb_sectors; - acb->cluster_offset = get_cluster_offset(bs, acb->sector_num << 9, &acb->n); + acb->cluster_offset = + qcow2_get_cluster_offset(bs, acb->sector_num << 9, &acb->n); index_in_cluster = acb->sector_num & (s->cluster_sectors - 1); if (!acb->cluster_offset) { if (bs->backing_hd) { /* read from the base image */ - n1 = backing_read1(bs->backing_hd, acb->sector_num, + n1 = qcow2_backing_read1(bs->backing_hd, acb->sector_num, acb->buf, acb->n); if (n1 > 0) { acb->hd_iov.iov_base = (void *)acb->buf; @@ -1349,7 +455,7 @@ static void qcow_aio_read_cb(void *opaque, int ret) } } else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) { /* add AIO support for compressed blocks ? */ - if (decompress_cluster(s, acb->cluster_offset) < 0) + if (qcow2_decompress_cluster(s, acb->cluster_offset) < 0) goto done; memcpy(acb->buf, s->cluster_cache + index_in_cluster * 512, 512 * acb->n); @@ -1436,8 +542,8 @@ static void qcow_aio_write_cb(void *opaque, int ret) 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); + if (qcow2_alloc_cluster_link_l2(bs, acb->cluster_offset, &acb->l2meta) < 0) { + qcow2_free_any_clusters(bs, acb->cluster_offset, acb->l2meta.nb_clusters); goto done; } @@ -1457,7 +563,7 @@ static void qcow_aio_write_cb(void *opaque, int ret) 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, + acb->cluster_offset = qcow2_alloc_cluster_offset(bs, acb->sector_num << 9, index_in_cluster, n_end, &acb->n, &acb->l2meta); if (!acb->cluster_offset || (acb->cluster_offset & 511) != 0) { @@ -1469,7 +575,7 @@ static void qcow_aio_write_cb(void *opaque, int ret) acb->cluster_data = qemu_mallocz(QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); } - encrypt_sectors(s, acb->sector_num, acb->cluster_data, acb->buf, + qcow2_encrypt_sectors(s, acb->sector_num, acb->cluster_data, acb->buf, acb->n, 1, &s->aes_encrypt_key); src_buf = acb->cluster_data; } else { @@ -1518,39 +624,10 @@ static void qcow_close(BlockDriverState *bs) qemu_free(s->l2_cache); qemu_free(s->cluster_cache); qemu_free(s->cluster_data); - refcount_close(bs); + qcow2_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 get_bits_from_size(size_t size) { int res = 0; @@ -1657,10 +734,12 @@ static int qcow_create2(const char *filename, int64_t total_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); + qcow2_create_refcount_update(s, 0, header_size); + qcow2_create_refcount_update(s, s->l1_table_offset, + l1_size * sizeof(uint64_t)); + qcow2_create_refcount_update(s, s->refcount_table_offset, s->cluster_size); + qcow2_create_refcount_update(s, s->refcount_block_offset, + ref_clusters * s->cluster_size); /* write all the data */ write(fd, &header, sizeof(header)); @@ -1703,7 +782,7 @@ static int qcow_create(const char *filename, QEMUOptionParameter *options) const char *backing_fmt = NULL; uint64_t sectors = 0; int flags = 0; - size_t cluster_size = 4096; + size_t cluster_size = 65536; /* Read out options */ while (options && options->name) { @@ -1801,8 +880,8 @@ static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num, /* could not compress: write normal cluster */ bdrv_write(bs, sector_num, buf, s->cluster_sectors); } else { - cluster_offset = alloc_compressed_cluster_offset(bs, sector_num << 9, - out_len); + cluster_offset = qcow2_alloc_compressed_cluster_offset(bs, + sector_num << 9, out_len); if (!cluster_offset) return -1; cluster_offset &= s->cluster_offset_mask; @@ -1831,1108 +910,10 @@ static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 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; - - if (!s->nb_snapshots) { - *psn_tab = NULL; - return s->nb_snapshots; - } - - 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; -} - - -static int64_t alloc_refcount_block(BlockDriverState *bs, int64_t cluster_index) -{ - BDRVQcowState *s = bs->opaque; - int64_t offset, refcount_block_offset; - int ret, refcount_table_index; - uint64_t data64; - - /* Find L1 index and grow refcount table if needed */ - refcount_table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT); - if (refcount_table_index >= s->refcount_table_size) { - ret = grow_refcount_table(bs, refcount_table_index + 1); - if (ret < 0) - return ret; - } - - /* Load or allocate the refcount block */ - refcount_block_offset = s->refcount_table[refcount_table_index]; - if (!refcount_block_offset) { - /* 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; - } - } - - return refcount_block_offset; -} - -/* addend must be 1 or -1 */ -static int update_cluster_refcount(BlockDriverState *bs, - int64_t cluster_index, - int addend) -{ - BDRVQcowState *s = bs->opaque; - int ret; - - ret = update_refcount(bs, cluster_index << s->cluster_bits, 1, addend); - if (ret < 0) { - return ret; - } - - return get_refcount(bs, cluster_index); -} - -/* XXX: cache several refcount block clusters ? */ -static int update_refcount(BlockDriverState *bs, - int64_t offset, int64_t length, - int addend) -{ - BDRVQcowState *s = bs->opaque; - int64_t start, last, cluster_offset; - int64_t refcount_block_offset = 0; - int64_t table_index = -1, old_table_index; - int first_index = -1, last_index = -1; - -#ifdef DEBUG_ALLOC2 - printf("update_refcount: offset=%lld size=%lld addend=%d\n", - offset, length, addend); -#endif - if (length <= 0) - return -EINVAL; - 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) - { - int block_index, refcount; - int64_t cluster_index = cluster_offset >> s->cluster_bits; - - /* Only write refcount block to disk when we are done with it */ - old_table_index = table_index; - table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT); - if ((old_table_index >= 0) && (table_index != old_table_index)) { - size_t size = (last_index - first_index + 1) << REFCOUNT_SHIFT; - if (bdrv_pwrite(s->hd, - refcount_block_offset + (first_index << REFCOUNT_SHIFT), - &s->refcount_block_cache[first_index], size) != size) - { - return -EIO; - } - - first_index = -1; - last_index = -1; - } - - /* Load the refcount block and allocate it if needed */ - refcount_block_offset = alloc_refcount_block(bs, cluster_index); - if (refcount_block_offset < 0) { - return refcount_block_offset; - } - - /* we can update the count and save it */ - block_index = cluster_index & - ((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1); - if (first_index == -1 || block_index < first_index) { - first_index = block_index; - } - if (block_index > last_index) { - last_index = block_index; - } - - 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); - } - - /* Write last changed block to disk */ - if (refcount_block_offset != 0) { - size_t size = (last_index - first_index + 1) << REFCOUNT_SHIFT; - if (bdrv_pwrite(s->hd, - refcount_block_offset + (first_index << REFCOUNT_SHIFT), - &s->refcount_block_cache[first_index], size) != size) - { - return -EIO; - } - } - - return 0; -} - -/* - * 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); + return qcow2_check_refcounts(bs); } #if 0 @@ -3025,10 +1006,10 @@ static BlockDriver bdrv_qcow2 = { .bdrv_aio_writev = qcow_aio_writev, .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_snapshot_create = qcow2_snapshot_create, + .bdrv_snapshot_goto = qcow2_snapshot_goto, + .bdrv_snapshot_delete = qcow2_snapshot_delete, + .bdrv_snapshot_list = qcow2_snapshot_list, .bdrv_get_info = qcow_get_info, .bdrv_put_buffer = qcow_put_buffer, |