diff options
Diffstat (limited to 'block/qcow2.c')
| -rw-r--r-- | block/qcow2.c | 871 |
1 files changed, 2 insertions, 869 deletions
diff --git a/block/qcow2.c b/block/qcow2.c index 14d8751..91903fe 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; @@ -110,77 +77,12 @@ typedef struct __attribute__((packed)) QCowSnapshotHeader { /* 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) { @@ -482,7 +384,7 @@ static int copy_sectors(BlockDriverState *bs, uint64_t start_sect, return 0; } -static void l2_cache_reset(BlockDriverState *bs) +void l2_cache_reset(BlockDriverState *bs) { BDRVQcowState *s = bs->opaque; @@ -691,11 +593,6 @@ static uint64_t *l2_allocate(BlockDriverState *bs, int l1_index) 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) { @@ -1522,35 +1419,6 @@ static void qcow_close(BlockDriverState *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; @@ -1834,117 +1702,6 @@ static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) /*********************************************************/ /* 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) { @@ -2306,630 +2063,6 @@ static int qcow_snapshot_list(BlockDriverState *bs, 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); |