/* * 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/osdep.h" #include "block/block_int.h" #include "sysemu/block-backend.h" #include "qemu/module.h" #include #include "block/qcow2.h" #include "qemu/error-report.h" #include "qapi/qmp/qerror.h" #include "qapi/qmp/qbool.h" #include "qapi/util.h" #include "qapi/qmp/types.h" #include "qapi-event.h" #include "trace.h" #include "qemu/option_int.h" #include "qemu/cutils.h" #include "qemu/bswap.h" #include "qapi/opts-visitor.h" #include "qapi-visit.h" #include "block/crypto.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. */ typedef struct { uint32_t magic; uint32_t len; } QEMU_PACKED QCowExtension; #define QCOW2_EXT_MAGIC_END 0 #define QCOW2_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA #define QCOW2_EXT_MAGIC_FEATURE_TABLE 0x6803f857 #define QCOW2_EXT_MAGIC_CRYPTO_HEADER 0x0537be77 static int qcow2_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) >= 2) return 100; else return 0; } static ssize_t qcow2_crypto_hdr_read_func(QCryptoBlock *block, size_t offset, uint8_t *buf, size_t buflen, void *opaque, Error **errp) { BlockDriverState *bs = opaque; BDRVQcow2State *s = bs->opaque; ssize_t ret; if ((offset + buflen) > s->crypto_header.length) { error_setg(errp, "Request for data outside of extension header"); return -1; } ret = bdrv_pread(bs->file, s->crypto_header.offset + offset, buf, buflen); if (ret < 0) { error_setg_errno(errp, -ret, "Could not read encryption header"); return -1; } return ret; } static ssize_t qcow2_crypto_hdr_init_func(QCryptoBlock *block, size_t headerlen, void *opaque, Error **errp) { BlockDriverState *bs = opaque; BDRVQcow2State *s = bs->opaque; int64_t ret; int64_t clusterlen; ret = qcow2_alloc_clusters(bs, headerlen); if (ret < 0) { error_setg_errno(errp, -ret, "Cannot allocate cluster for LUKS header size %zu", headerlen); return -1; } s->crypto_header.length = headerlen; s->crypto_header.offset = ret; /* Zero fill remaining space in cluster so it has predictable * content in case of future spec changes */ clusterlen = size_to_clusters(s, headerlen) * s->cluster_size; ret = bdrv_pwrite_zeroes(bs->file, ret + headerlen, clusterlen - headerlen, 0); if (ret < 0) { error_setg_errno(errp, -ret, "Could not zero fill encryption header"); return -1; } return ret; } static ssize_t qcow2_crypto_hdr_write_func(QCryptoBlock *block, size_t offset, const uint8_t *buf, size_t buflen, void *opaque, Error **errp) { BlockDriverState *bs = opaque; BDRVQcow2State *s = bs->opaque; ssize_t ret; if ((offset + buflen) > s->crypto_header.length) { error_setg(errp, "Request for data outside of extension header"); return -1; } ret = bdrv_pwrite(bs->file, s->crypto_header.offset + offset, buf, buflen); if (ret < 0) { error_setg_errno(errp, -ret, "Could not read encryption header"); return -1; } return ret; } /* * 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 qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset, uint64_t end_offset, void **p_feature_table, int flags, Error **errp) { BDRVQcow2State *s = bs->opaque; QCowExtension ext; uint64_t offset; int ret; #ifdef DEBUG_EXT printf("qcow2_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("qcow2_read_extension: suspicious offset %lu\n", offset); printf("attempting to read extended header in offset %lu\n", offset); #endif ret = bdrv_pread(bs->file, offset, &ext, sizeof(ext)); if (ret < 0) { error_setg_errno(errp, -ret, "qcow2_read_extension: ERROR: " "pread fail from offset %" PRIu64, 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 if (offset > end_offset || ext.len > end_offset - offset) { error_setg(errp, "Header extension too large"); return -EINVAL; } switch (ext.magic) { case QCOW2_EXT_MAGIC_END: return 0; case QCOW2_EXT_MAGIC_BACKING_FORMAT: if (ext.len >= sizeof(bs->backing_format)) { error_setg(errp, "ERROR: ext_backing_format: len=%" PRIu32 " too large (>=%zu)", ext.len, sizeof(bs->backing_format)); return 2; } ret = bdrv_pread(bs->file, offset, bs->backing_format, ext.len); if (ret < 0) { error_setg_errno(errp, -ret, "ERROR: ext_backing_format: " "Could not read format name"); return 3; } bs->backing_format[ext.len] = '\0'; s->image_backing_format = g_strdup(bs->backing_format); #ifdef DEBUG_EXT printf("Qcow2: Got format extension %s\n", bs->backing_format); #endif break; case QCOW2_EXT_MAGIC_FEATURE_TABLE: if (p_feature_table != NULL) { void* feature_table = g_malloc0(ext.len + 2 * sizeof(Qcow2Feature)); ret = bdrv_pread(bs->file, offset , feature_table, ext.len); if (ret < 0) { error_setg_errno(errp, -ret, "ERROR: ext_feature_table: " "Could not read table"); return ret; } *p_feature_table = feature_table; } break; case QCOW2_EXT_MAGIC_CRYPTO_HEADER: { unsigned int cflags = 0; if (s->crypt_method_header != QCOW_CRYPT_LUKS) { error_setg(errp, "CRYPTO header extension only " "expected with LUKS encryption method"); return -EINVAL; } if (ext.len != sizeof(Qcow2CryptoHeaderExtension)) { error_setg(errp, "CRYPTO header extension size %u, " "but expected size %zu", ext.len, sizeof(Qcow2CryptoHeaderExtension)); return -EINVAL; } ret = bdrv_pread(bs->file, offset, &s->crypto_header, ext.len); if (ret < 0) { error_setg_errno(errp, -ret, "Unable to read CRYPTO header extension"); return ret; } be64_to_cpus(&s->crypto_header.offset); be64_to_cpus(&s->crypto_header.length); if ((s->crypto_header.offset % s->cluster_size) != 0) { error_setg(errp, "Encryption header offset '%" PRIu64 "' is " "not a multiple of cluster size '%u'", s->crypto_header.offset, s->cluster_size); return -EINVAL; } if (flags & BDRV_O_NO_IO) { cflags |= QCRYPTO_BLOCK_OPEN_NO_IO; } s->crypto = qcrypto_block_open(s->crypto_opts, qcow2_crypto_hdr_read_func, bs, cflags, errp); if (!s->crypto) { return -EINVAL; } } break; default: /* unknown magic - save it in case we need to rewrite the header */ { Qcow2UnknownHeaderExtension *uext; uext = g_malloc0(sizeof(*uext) + ext.len); uext->magic = ext.magic; uext->len = ext.len; QLIST_INSERT_HEAD(&s->unknown_header_ext, uext, next); ret = bdrv_pread(bs->file, offset , uext->data, uext->len); if (ret < 0) { error_setg_errno(errp, -ret, "ERROR: unknown extension: " "Could not read data"); return ret; } } break; } offset += ((ext.len + 7) & ~7); } return 0; } static void cleanup_unknown_header_ext(BlockDriverState *bs) { BDRVQcow2State *s = bs->opaque; Qcow2UnknownHeaderExtension *uext, *next; QLIST_FOREACH_SAFE(uext, &s->unknown_header_ext, next, next) { QLIST_REMOVE(uext, next); g_free(uext); } } static void report_unsupported_feature(Error **errp, Qcow2Feature *table, uint64_t mask) { char *features = g_strdup(""); char *old; while (table && table->name[0] != '\0') { if (table->type == QCOW2_FEAT_TYPE_INCOMPATIBLE) { if (mask & (1ULL << table->bit)) { old = features; features = g_strdup_printf("%s%s%.46s", old, *old ? ", " : "", table->name); g_free(old); mask &= ~(1ULL << table->bit); } } table++; } if (mask) { old = features; features = g_strdup_printf("%s%sUnknown incompatible feature: %" PRIx64, old, *old ? ", " : "", mask); g_free(old); } error_setg(errp, "Unsupported qcow2 feature(s): %s", features); g_free(features); } /* * Sets the dirty bit and flushes afterwards if necessary. * * The incompatible_features bit is only set if the image file header was * updated successfully. Therefore it is not required to check the return * value of this function. */ int qcow2_mark_dirty(BlockDriverState *bs) { BDRVQcow2State *s = bs->opaque; uint64_t val; int ret; assert(s->qcow_version >= 3); if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { return 0; /* already dirty */ } val = cpu_to_be64(s->incompatible_features | QCOW2_INCOMPAT_DIRTY); ret = bdrv_pwrite(bs->file, offsetof(QCowHeader, incompatible_features), &val, sizeof(val)); if (ret < 0) { return ret; } ret = bdrv_flush(bs->file->bs); if (ret < 0) { return ret; } /* Only treat image as dirty if the header was updated successfully */ s->incompatible_features |= QCOW2_INCOMPAT_DIRTY; return 0; } /* * Clears the dirty bit and flushes before if necessary. Only call this * function when there are no pending requests, it does not guard against * concurrent requests dirtying the image. */ static int qcow2_mark_clean(BlockDriverState *bs) { BDRVQcow2State *s = bs->opaque; if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { int ret; s->incompatible_features &= ~QCOW2_INCOMPAT_DIRTY; ret = bdrv_flush(bs); if (ret < 0) { return ret; } return qcow2_update_header(bs); } return 0; } /* * Marks the image as corrupt. */ int qcow2_mark_corrupt(BlockDriverState *bs) { BDRVQcow2State *s = bs->opaque; s->incompatible_features |= QCOW2_INCOMPAT_CORRUPT; return qcow2_update_header(bs); } /* * Marks the image as consistent, i.e., unsets the corrupt bit, and flushes * before if necessary. */ int qcow2_mark_consistent(BlockDriverState *bs) { BDRVQcow2State *s = bs->opaque; if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) { int ret = bdrv_flush(bs); if (ret < 0) { return ret; } s->incompatible_features &= ~QCOW2_INCOMPAT_CORRUPT; return qcow2_update_header(bs); } return 0; } static int qcow2_check(BlockDriverState *bs, BdrvCheckResult *result, BdrvCheckMode fix) { int ret = qcow2_check_refcounts(bs, result, fix); if (ret < 0) { return ret; } if (fix && result->check_errors == 0 && result->corruptions == 0) { ret = qcow2_mark_clean(bs); if (ret < 0) { return ret; } return qcow2_mark_consistent(bs); } return ret; } static int validate_table_offset(BlockDriverState *bs, uint64_t offset, uint64_t entries, size_t entry_len) { BDRVQcow2State *s = bs->opaque; uint64_t size; /* Use signed INT64_MAX as the maximum even for uint64_t header fields, * because values will be passed to qemu functions taking int64_t. */ if (entries > INT64_MAX / entry_len) { return -EINVAL; } size = entries * entry_len; if (INT64_MAX - size < offset) { return -EINVAL; } /* Tables must be cluster aligned */ if (offset_into_cluster(s, offset) != 0) { return -EINVAL; } return 0; } static QemuOptsList qcow2_runtime_opts = { .name = "qcow2", .head = QTAILQ_HEAD_INITIALIZER(qcow2_runtime_opts.head), .desc = { { .name = QCOW2_OPT_LAZY_REFCOUNTS, .type = QEMU_OPT_BOOL, .help = "Postpone refcount updates", }, { .name = QCOW2_OPT_DISCARD_REQUEST, .type = QEMU_OPT_BOOL, .help = "Pass guest discard requests to the layer below", }, { .name = QCOW2_OPT_DISCARD_SNAPSHOT, .type = QEMU_OPT_BOOL, .help = "Generate discard requests when snapshot related space " "is freed", }, { .name = QCOW2_OPT_DISCARD_OTHER, .type = QEMU_OPT_BOOL, .help = "Generate discard requests when other clusters are freed", }, { .name = QCOW2_OPT_OVERLAP, .type = QEMU_OPT_STRING, .help = "Selects which overlap checks to perform from a range of " "templates (none, constant, cached, all)", }, { .name = QCOW2_OPT_OVERLAP_TEMPLATE, .type = QEMU_OPT_STRING, .help = "Selects which overlap checks to perform from a range of " "templates (none, constant, cached, all)", }, { .name = QCOW2_OPT_OVERLAP_MAIN_HEADER, .type = QEMU_OPT_BOOL, .help = "Check for unintended writes into the main qcow2 header", }, { .name = QCOW2_OPT_OVERLAP_ACTIVE_L1, .type = QEMU_OPT_BOOL, .help = "Check for unintended writes into the active L1 table", }, { .name = QCOW2_OPT_OVERLAP_ACTIVE_L2, .type = QEMU_OPT_BOOL, .help = "Check for unintended writes into an active L2 table", }, { .name = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE, .type = QEMU_OPT_BOOL, .help = "Check for unintended writes into the refcount table", }, { .name = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK, .type = QEMU_OPT_BOOL, .help = "Check for unintended writes into a refcount block", }, { .name = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE, .type = QEMU_OPT_BOOL, .help = "Check for unintended writes into the snapshot table", }, { .name = QCOW2_OPT_OVERLAP_INACTIVE_L1, .type = QEMU_OPT_BOOL, .help = "Check for unintended writes into an inactive L1 table", }, { .name = QCOW2_OPT_OVERLAP_INACTIVE_L2, .type = QEMU_OPT_BOOL, .help = "Check for unintended writes into an inactive L2 table", }, { .name = QCOW2_OPT_CACHE_SIZE, .type = QEMU_OPT_SIZE, .help = "Maximum combined metadata (L2 tables and refcount blocks) " "cache size", }, { .name = QCOW2_OPT_L2_CACHE_SIZE, .type = QEMU_OPT_SIZE, .help = "Maximum L2 table cache size", }, { .name = QCOW2_OPT_REFCOUNT_CACHE_SIZE, .type = QEMU_OPT_SIZE, .help = "Maximum refcount block cache size", }, { .name = QCOW2_OPT_CACHE_CLEAN_INTERVAL, .type = QEMU_OPT_NUMBER, .help = "Clean unused cache entries after this time (in seconds)", }, BLOCK_CRYPTO_OPT_DEF_KEY_SECRET("encrypt.", "ID of secret providing qcow2 AES key or LUKS passphrase"), { /* end of list */ } }, }; static const char *overlap_bool_option_names[QCOW2_OL_MAX_BITNR] = { [QCOW2_OL_MAIN_HEADER_BITNR] = QCOW2_OPT_OVERLAP_MAIN_HEADER, [QCOW2_OL_ACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L1, [QCOW2_OL_ACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L2, [QCOW2_OL_REFCOUNT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE, [QCOW2_OL_REFCOUNT_BLOCK_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK, [QCOW2_OL_SNAPSHOT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE, [QCOW2_OL_INACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L1, [QCOW2_OL_INACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L2, }; static void cache_clean_timer_cb(void *opaque) { BlockDriverState *bs = opaque; BDRVQcow2State *s = bs->opaque; qcow2_cache_clean_unused(bs, s->l2_table_cache); qcow2_cache_clean_unused(bs, s->refcount_block_cache); timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + (int64_t) s->cache_clean_interval * 1000); } static void cache_clean_timer_init(BlockDriverState *bs, AioContext *context) { BDRVQcow2State *s = bs->opaque; if (s->cache_clean_interval > 0) { s->cache_clean_timer = aio_timer_new(context, QEMU_CLOCK_VIRTUAL, SCALE_MS, cache_clean_timer_cb, bs); timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + (int64_t) s->cache_clean_interval * 1000); } } static void cache_clean_timer_del(BlockDriverState *bs) { BDRVQcow2State *s = bs->opaque; if (s->cache_clean_timer) { timer_del(s->cache_clean_timer); timer_free(s->cache_clean_timer); s->cache_clean_timer = NULL; } } static void qcow2_detach_aio_context(BlockDriverState *bs) { cache_clean_timer_del(bs); } static void qcow2_attach_aio_context(BlockDriverState *bs, AioContext *new_context) { cache_clean_timer_init(bs, new_context); } static void read_cache_sizes(BlockDriverState *bs, QemuOpts *opts, uint64_t *l2_cache_size, uint64_t *refcount_cache_size, Error **errp) { BDRVQcow2State *s = bs->opaque; uint64_t combined_cache_size; bool l2_cache_size_set, refcount_cache_size_set, combined_cache_size_set; combined_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_CACHE_SIZE); l2_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_L2_CACHE_SIZE); refcount_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_REFCOUNT_CACHE_SIZE); combined_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_CACHE_SIZE, 0); *l2_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_L2_CACHE_SIZE, 0); *refcount_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_REFCOUNT_CACHE_SIZE, 0); if (combined_cache_size_set) { if (l2_cache_size_set && refcount_cache_size_set) { error_setg(errp, QCOW2_OPT_CACHE_SIZE ", " QCOW2_OPT_L2_CACHE_SIZE " and " QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not be set " "the same time"); return; } else if (*l2_cache_size > combined_cache_size) { error_setg(errp, QCOW2_OPT_L2_CACHE_SIZE " may not exceed " QCOW2_OPT_CACHE_SIZE); return; } else if (*refcount_cache_size > combined_cache_size) { error_setg(errp, QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not exceed " QCOW2_OPT_CACHE_SIZE); return; } if (l2_cache_size_set) { *refcount_cache_size = combined_cache_size - *l2_cache_size; } else if (refcount_cache_size_set) { *l2_cache_size = combined_cache_size - *refcount_cache_size; } else { *refcount_cache_size = combined_cache_size / (DEFAULT_L2_REFCOUNT_SIZE_RATIO + 1); *l2_cache_size = combined_cache_size - *refcount_cache_size; } } else { if (!l2_cache_size_set && !refcount_cache_size_set) { *l2_cache_size = MAX(DEFAULT_L2_CACHE_BYTE_SIZE, (uint64_t)DEFAULT_L2_CACHE_CLUSTERS * s->cluster_size); *refcount_cache_size = *l2_cache_size / DEFAULT_L2_REFCOUNT_SIZE_RATIO; } else if (!l2_cache_size_set) { *l2_cache_size = *refcount_cache_size * DEFAULT_L2_REFCOUNT_SIZE_RATIO; } else if (!refcount_cache_size_set) { *refcount_cache_size = *l2_cache_size / DEFAULT_L2_REFCOUNT_SIZE_RATIO; } } } typedef struct Qcow2ReopenState { Qcow2Cache *l2_table_cache; Qcow2Cache *refcount_block_cache; bool use_lazy_refcounts; int overlap_check; bool discard_passthrough[QCOW2_DISCARD_MAX]; uint64_t cache_clean_interval; QCryptoBlockOpenOptions *crypto_opts; /* Disk encryption runtime options */ } Qcow2ReopenState; static int qcow2_update_options_prepare(BlockDriverState *bs, Qcow2ReopenState *r, QDict *options, int flags, Error **errp) { BDRVQcow2State *s = bs->opaque; QemuOpts *opts = NULL; const char *opt_overlap_check, *opt_overlap_check_template; int overlap_check_template = 0; uint64_t l2_cache_size, refcount_cache_size; int i; const char *encryptfmt; QDict *encryptopts = NULL; Error *local_err = NULL; int ret; qdict_extract_subqdict(options, &encryptopts, "encrypt."); encryptfmt = qdict_get_try_str(encryptopts, "format"); opts = qemu_opts_create(&qcow2_runtime_opts, NULL, 0, &error_abort); qemu_opts_absorb_qdict(opts, options, &local_err); if (local_err) { error_propagate(errp, local_err); ret = -EINVAL; goto fail; } /* get L2 table/refcount block cache size from command line options */ read_cache_sizes(bs, opts, &l2_cache_size, &refcount_cache_size, &local_err); if (local_err) { error_propagate(errp, local_err); ret = -EINVAL; goto fail; } l2_cache_size /= s->cluster_size; if (l2_cache_size < MIN_L2_CACHE_SIZE) { l2_cache_size = MIN_L2_CACHE_SIZE; } if (l2_cache_size > INT_MAX) { error_setg(errp, "L2 cache size too big"); ret = -EINVAL; goto fail; } refcount_cache_size /= s->cluster_size; if (refcount_cache_size < MIN_REFCOUNT_CACHE_SIZE) { refcount_cache_size = MIN_REFCOUNT_CACHE_SIZE; } if (refcount_cache_size > INT_MAX) { error_setg(errp, "Refcount cache size too big"); ret = -EINVAL; goto fail; } /* alloc new L2 table/refcount block cache, flush old one */ if (s->l2_table_cache) { ret = qcow2_cache_flush(bs, s->l2_table_cache); if (ret) { error_setg_errno(errp, -ret, "Failed to flush the L2 table cache"); goto fail; } } if (s->refcount_block_cache) { ret = qcow2_cache_flush(bs, s->refcount_block_cache); if (ret) { error_setg_errno(errp, -ret, "Failed to flush the refcount block cache"); goto fail; } } r->l2_table_cache = qcow2_cache_create(bs, l2_cache_size); r->refcount_block_cache = qcow2_cache_create(bs, refcount_cache_size); if (r->l2_table_cache == NULL || r->refcount_block_cache == NULL) { error_setg(errp, "Could not allocate metadata caches"); ret = -ENOMEM; goto fail; } /* New interval for cache cleanup timer */ r->cache_clean_interval = qemu_opt_get_number(opts, QCOW2_OPT_CACHE_CLEAN_INTERVAL, s->cache_clean_interval); #ifndef CONFIG_LINUX if (r->cache_clean_interval != 0) { error_setg(errp, QCOW2_OPT_CACHE_CLEAN_INTERVAL " not supported on this host"); ret = -EINVAL; goto fail; } #endif if (r->cache_clean_interval > UINT_MAX) { error_setg(errp, "Cache clean interval too big"); ret = -EINVAL; goto fail; } /* lazy-refcounts; flush if going from enabled to disabled */ r->use_lazy_refcounts = qemu_opt_get_bool(opts, QCOW2_OPT_LAZY_REFCOUNTS, (s->compatible_features & QCOW2_COMPAT_LAZY_REFCOUNTS)); if (r->use_lazy_refcounts && s->qcow_version < 3) { error_setg(errp, "Lazy refcounts require a qcow2 image with at least " "qemu 1.1 compatibility level"); ret = -EINVAL; goto fail; } if (s->use_lazy_refcounts && !r->use_lazy_refcounts) { ret = qcow2_mark_clean(bs); if (ret < 0) { error_setg_errno(errp, -ret, "Failed to disable lazy refcounts"); goto fail; } } /* Overlap check options */ opt_overlap_check = qemu_opt_get(opts, QCOW2_OPT_OVERLAP); opt_overlap_check_template = qemu_opt_get(opts, QCOW2_OPT_OVERLAP_TEMPLATE); if (opt_overlap_check_template && opt_overlap_check && strcmp(opt_overlap_check_template, opt_overlap_check)) { error_setg(errp, "Conflicting values for qcow2 options '" QCOW2_OPT_OVERLAP "' ('%s') and '" QCOW2_OPT_OVERLAP_TEMPLATE "' ('%s')", opt_overlap_check, opt_overlap_check_template); ret = -EINVAL; goto fail; } if (!opt_overlap_check) { opt_overlap_check = opt_overlap_check_template ?: "cached"; } if (!strcmp(opt_overlap_check, "none")) { overlap_check_template = 0; } else if (!strcmp(opt_overlap_check, "constant")) { overlap_check_template = QCOW2_OL_CONSTANT; } else if (!strcmp(opt_overlap_check, "cached")) { overlap_check_template = QCOW2_OL_CACHED; } else if (!strcmp(opt_overlap_check, "all")) { overlap_check_template = QCOW2_OL_ALL; } else { error_setg(errp, "Unsupported value '%s' for qcow2 option " "'overlap-check'. Allowed are any of the following: " "none, constant, cached, all", opt_overlap_check); ret = -EINVAL; goto fail; } r->overlap_check = 0; for (i = 0; i < QCOW2_OL_MAX_BITNR; i++) { /* overlap-check defines a template bitmask, but every flag may be * overwritten through the associated boolean option */ r->overlap_check |= qemu_opt_get_bool(opts, overlap_bool_option_names[i], overlap_check_template & (1 << i)) << i; } r->discard_passthrough[QCOW2_DISCARD_NEVER] = false; r->discard_passthrough[QCOW2_DISCARD_ALWAYS] = true; r->discard_passthrough[QCOW2_DISCARD_REQUEST] = qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_REQUEST, flags & BDRV_O_UNMAP); r->discard_passthrough[QCOW2_DISCARD_SNAPSHOT] = qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_SNAPSHOT, true); r->discard_passthrough[QCOW2_DISCARD_OTHER] = qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_OTHER, false); switch (s->crypt_method_header) { case QCOW_CRYPT_NONE: if (encryptfmt) { error_setg(errp, "No encryption in image header, but options " "specified format '%s'", encryptfmt); ret = -EINVAL; goto fail; } break; case QCOW_CRYPT_AES: if (encryptfmt && !g_str_equal(encryptfmt, "aes")) { error_setg(errp, "Header reported 'aes' encryption format but " "options specify '%s'", encryptfmt); ret = -EINVAL; goto fail; } qdict_del(encryptopts, "format"); r->crypto_opts = block_crypto_open_opts_init( Q_CRYPTO_BLOCK_FORMAT_QCOW, encryptopts, errp); break; case QCOW_CRYPT_LUKS: if (encryptfmt && !g_str_equal(encryptfmt, "luks")) { error_setg(errp, "Header reported 'luks' encryption format but " "options specify '%s'", encryptfmt); ret = -EINVAL; goto fail; } qdict_del(encryptopts, "format"); r->crypto_opts = block_crypto_open_opts_init( Q_CRYPTO_BLOCK_FORMAT_LUKS, encryptopts, errp); break; default: error_setg(errp, "Unsupported encryption method %d", s->crypt_method_header); break; } if (s->crypt_method_header != QCOW_CRYPT_NONE && !r->crypto_opts) { ret = -EINVAL; goto fail; } ret = 0; fail: QDECREF(encryptopts); qemu_opts_del(opts); opts = NULL; return ret; } static void qcow2_update_options_commit(BlockDriverState *bs, Qcow2ReopenState *r) { BDRVQcow2State *s = bs->opaque; int i; if (s->l2_table_cache) { qcow2_cache_destroy(bs, s->l2_table_cache); } if (s->refcount_block_cache) { qcow2_cache_destroy(bs, s->refcount_block_cache); } s->l2_table_cache = r->l2_table_cache; s->refcount_block_cache = r->refcount_block_cache; s->overlap_check = r->overlap_check; s->use_lazy_refcounts = r->use_lazy_refcounts; for (i = 0; i < QCOW2_DISCARD_MAX; i++) { s->discard_passthrough[i] = r->discard_passthrough[i]; } if (s->cache_clean_interval != r->cache_clean_interval) { cache_clean_timer_del(bs); s->cache_clean_interval = r->cache_clean_interval; cache_clean_timer_init(bs, bdrv_get_aio_context(bs)); } qapi_free_QCryptoBlockOpenOptions(s->crypto_opts); s->crypto_opts = r->crypto_opts; } static void qcow2_update_options_abort(BlockDriverState *bs, Qcow2ReopenState *r) { if (r->l2_table_cache) { qcow2_cache_destroy(bs, r->l2_table_cache); } if (r->refcount_block_cache) { qcow2_cache_destroy(bs, r->refcount_block_cache); } qapi_free_QCryptoBlockOpenOptions(r->crypto_opts); } static int qcow2_update_options(BlockDriverState *bs, QDict *options, int flags, Error **errp) { Qcow2ReopenState r = {}; int ret; ret = qcow2_update_options_prepare(bs, &r, options, flags, errp); if (ret >= 0) { qcow2_update_options_commit(bs, &r); } else { qcow2_update_options_abort(bs, &r); } return ret; } static int qcow2_do_open(BlockDriverState *bs, QDict *options, int flags, Error **errp) { BDRVQcow2State *s = bs->opaque; unsigned int len, i; int ret = 0; QCowHeader header; Error *local_err = NULL; uint64_t ext_end; uint64_t l1_vm_state_index; ret = bdrv_pread(bs->file, 0, &header, sizeof(header)); if (ret < 0) { error_setg_errno(errp, -ret, "Could not read qcow2 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) { error_setg(errp, "Image is not in qcow2 format"); ret = -EINVAL; goto fail; } if (header.version < 2 || header.version > 3) { error_setg(errp, "Unsupported qcow2 version %" PRIu32, header.version); ret = -ENOTSUP; goto fail; } s->qcow_version = header.version; /* Initialise cluster size */ if (header.cluster_bits < MIN_CLUSTER_BITS || header.cluster_bits > MAX_CLUSTER_BITS) { error_setg(errp, "Unsupported cluster size: 2^%" PRIu32, header.cluster_bits); ret = -EINVAL; goto fail; } s->cluster_bits = header.cluster_bits; s->cluster_size = 1 << s->cluster_bits; s->cluster_sectors = 1 << (s->cluster_bits - 9); /* Initialise version 3 header fields */ if (header.version == 2) { header.incompatible_features = 0; header.compatible_features = 0; header.autoclear_features = 0; header.refcount_order = 4; header.header_length = 72; } else { be64_to_cpus(&header.incompatible_features); be64_to_cpus(&header.compatible_features); be64_to_cpus(&header.autoclear_features); be32_to_cpus(&header.refcount_order); be32_to_cpus(&header.header_length); if (header.header_length < 104) { error_setg(errp, "qcow2 header too short"); ret = -EINVAL; goto fail; } } if (header.header_length > s->cluster_size) { error_setg(errp, "qcow2 header exceeds cluster size"); ret = -EINVAL; goto fail; } if (header.header_length > sizeof(header)) { s->unknown_header_fields_size = header.header_length - sizeof(header); s->unknown_header_fields = g_malloc(s->unknown_header_fields_size); ret = bdrv_pread(bs->file, sizeof(header), s->unknown_header_fields, s->unknown_header_fields_size); if (ret < 0) { error_setg_errno(errp, -ret, "Could not read unknown qcow2 header " "fields"); goto fail; } } if (header.backing_file_offset > s->cluster_size) { error_setg(errp, "Invalid backing file offset"); ret = -EINVAL; goto fail; } if (header.backing_file_offset) { ext_end = header.backing_file_offset; } else { ext_end = 1 << header.cluster_bits; } /* Handle feature bits */ s->incompatible_features = header.incompatible_features; s->compatible_features = header.compatible_features; s->autoclear_features = header.autoclear_features; if (s->incompatible_features & ~QCOW2_INCOMPAT_MASK) { void *feature_table = NULL; qcow2_read_extensions(bs, header.header_length, ext_end, &feature_table, flags, NULL); report_unsupported_feature(errp, feature_table, s->incompatible_features & ~QCOW2_INCOMPAT_MASK); ret = -ENOTSUP; g_free(feature_table); goto fail; } if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) { /* Corrupt images may not be written to unless they are being repaired */ if ((flags & BDRV_O_RDWR) && !(flags & BDRV_O_CHECK)) { error_setg(errp, "qcow2: Image is corrupt; cannot be opened " "read/write"); ret = -EACCES; goto fail; } } /* Check support for various header values */ if (header.refcount_order > 6) { error_setg(errp, "Reference count entry width too large; may not " "exceed 64 bits"); ret = -EINVAL; goto fail; } s->refcount_order = header.refcount_order; s->refcount_bits = 1 << s->refcount_order; s->refcount_max = UINT64_C(1) << (s->refcount_bits - 1); s->refcount_max += s->refcount_max - 1; s->crypt_method_header = header.crypt_method; if (s->crypt_method_header) { if (bdrv_uses_whitelist() && s->crypt_method_header == QCOW_CRYPT_AES) { error_setg(errp, "Use of AES-CBC encrypted qcow2 images is no longer " "supported in system emulators"); error_append_hint(errp, "You can use 'qemu-img convert' to convert your " "image to an alternative supported format, such " "as unencrypted qcow2, or raw with the LUKS " "format instead.\n"); ret = -ENOSYS; goto fail; } if (s->crypt_method_header == QCOW_CRYPT_AES) { s->crypt_physical_offset = false; } else { /* Assuming LUKS and any future crypt methods we * add will all use physical offsets, due to the * fact that the alternative is insecure... */ s->crypt_physical_offset = true; } bs->encrypted = true; } s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */ s->l2_size = 1 << s->l2_bits; /* 2^(s->refcount_order - 3) is the refcount width in bytes */ s->refcount_block_bits = s->cluster_bits - (s->refcount_order - 3); s->refcount_block_size = 1 << s->refcount_block_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); if (header.refcount_table_clusters > qcow2_max_refcount_clusters(s)) { error_setg(errp, "Reference count table too large"); ret = -EINVAL; goto fail; } ret = validate_table_offset(bs, s->refcount_table_offset, s->refcount_table_size, sizeof(uint64_t)); if (ret < 0) { error_setg(errp, "Invalid reference count table offset"); goto fail; } /* Snapshot table offset/length */ if (header.nb_snapshots > QCOW_MAX_SNAPSHOTS) { error_setg(errp, "Too many snapshots"); ret = -EINVAL; goto fail; } ret = validate_table_offset(bs, header.snapshots_offset, header.nb_snapshots, sizeof(QCowSnapshotHeader)); if (ret < 0) { error_setg(errp, "Invalid snapshot table offset"); goto fail; } /* read the level 1 table */ if (header.l1_size > QCOW_MAX_L1_SIZE / sizeof(uint64_t)) { error_setg(errp, "Active L1 table too large"); ret = -EFBIG; goto fail; } s->l1_size = header.l1_size; l1_vm_state_index = size_to_l1(s, header.size); if (l1_vm_state_index > INT_MAX) { error_setg(errp, "Image is too big"); ret = -EFBIG; goto fail; } s->l1_vm_state_index = l1_vm_state_index; /* the L1 table must contain at least enough entries to put header.size bytes */ if (s->l1_size < s->l1_vm_state_index) { error_setg(errp, "L1 table is too small"); ret = -EINVAL; goto fail; } ret = validate_table_offset(bs, header.l1_table_offset, header.l1_size, sizeof(uint64_t)); if (ret < 0) { error_setg(errp, "Invalid L1 table offset"); goto fail; } s->l1_table_offset = header.l1_table_offset; if (s->l1_size > 0) { s->l1_table = qemu_try_blockalign(bs->file->bs, align_offset(s->l1_size * sizeof(uint64_t), 512)); if (s->l1_table == NULL) { error_setg(errp, "Could not allocate L1 table"); ret = -ENOMEM; goto fail; } ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table, s->l1_size * sizeof(uint64_t)); if (ret < 0) { error_setg_errno(errp, -ret, "Could not read L1 table"); goto fail; } for(i = 0;i < s->l1_size; i++) { be64_to_cpus(&s->l1_table[i]); } } /* Parse driver-specific options */ ret = qcow2_update_options(bs, options, flags, errp); if (ret < 0) { goto fail; } s->cluster_cache = g_malloc(s->cluster_size); /* one more sector for decompressed data alignment */ s->cluster_data = qemu_try_blockalign(bs->file->bs, QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size + 512); if (s->cluster_data == NULL) { error_setg(errp, "Could not allocate temporary cluster buffer"); ret = -ENOMEM; goto fail; } s->cluster_cache_offset = -1; s->flags = flags; ret = qcow2_refcount_init(bs); if (ret != 0) { error_setg_errno(errp, -ret, "Could not initialize refcount handling"); goto fail; } QLIST_INIT(&s->cluster_allocs); QTAILQ_INIT(&s->discards); /* read qcow2 extensions */ if (qcow2_read_extensions(bs, header.header_length, ext_end, NULL, flags, &local_err)) { error_propagate(errp, local_err); ret = -EINVAL; goto fail; } /* qcow2_read_extension may have set up the crypto context * if the crypt method needs a header region, some methods * don't need header extensions, so must check here */ if (s->crypt_method_header && !s->crypto) { if (s->crypt_method_header == QCOW_CRYPT_AES) { unsigned int cflags = 0; if (flags & BDRV_O_NO_IO) { cflags |= QCRYPTO_BLOCK_OPEN_NO_IO; } s->crypto = qcrypto_block_open(s->crypto_opts, NULL, NULL, cflags, errp); if (!s->crypto) { ret = -EINVAL; goto fail; } } else if (!(flags & BDRV_O_NO_IO)) { error_setg(errp, "Missing CRYPTO header for crypt method %d", s->crypt_method_header); ret = -EINVAL; goto fail; } } /* read the backing file name */ if (header.backing_file_offset != 0) { len = header.backing_file_size; if (len > MIN(1023, s->cluster_size - header.backing_file_offset) || len >= sizeof(bs->backing_file)) { error_setg(errp, "Backing file name too long"); ret = -EINVAL; goto fail; } ret = bdrv_pread(bs->file, header.backing_file_offset, bs->backing_file, len); if (ret < 0) { error_setg_errno(errp, -ret, "Could not read backing file name"); goto fail; } bs->backing_file[len] = '\0'; s->image_backing_file = g_strdup(bs->backing_file); } /* Internal snapshots */ s->snapshots_offset = header.snapshots_offset; s->nb_snapshots = header.nb_snapshots; ret = qcow2_read_snapshots(bs); if (ret < 0) { error_setg_errno(errp, -ret, "Could not read snapshots"); goto fail; } /* Clear unknown autoclear feature bits */ if (!bs->read_only && !(flags & BDRV_O_INACTIVE) && s->autoclear_features) { s->autoclear_features = 0; ret = qcow2_update_header(bs); if (ret < 0) { error_setg_errno(errp, -ret, "Could not update qcow2 header"); goto fail; } } /* Initialise locks */ qemu_co_mutex_init(&s->lock); bs->supported_zero_flags = BDRV_REQ_MAY_UNMAP; /* Repair image if dirty */ if (!(flags & (BDRV_O_CHECK | BDRV_O_INACTIVE)) && !bs->read_only && (s->incompatible_features & QCOW2_INCOMPAT_DIRTY)) { BdrvCheckResult result = {0}; ret = qcow2_check(bs, &result, BDRV_FIX_ERRORS | BDRV_FIX_LEAKS); if (ret < 0) { error_setg_errno(errp, -ret, "Could not repair dirty image"); goto fail; } } #ifdef DEBUG_ALLOC { BdrvCheckResult result = {0}; qcow2_check_refcounts(bs, &result, 0); } #endif return ret; fail: g_free(s->unknown_header_fields); cleanup_unknown_header_ext(bs); qcow2_free_snapshots(bs); qcow2_refcount_close(bs); qemu_vfree(s->l1_table); /* else pre-write overlap checks in cache_destroy may crash */ s->l1_table = NULL; cache_clean_timer_del(bs); if (s->l2_table_cache) { qcow2_cache_destroy(bs, s->l2_table_cache); } if (s->refcount_block_cache) { qcow2_cache_destroy(bs, s->refcount_block_cache); } g_free(s->cluster_cache); qemu_vfree(s->cluster_data); qcrypto_block_free(s->crypto); qapi_free_QCryptoBlockOpenOptions(s->crypto_opts); return ret; } static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, Error **errp) { bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, false, errp); if (!bs->file) { return -EINVAL; } return qcow2_do_open(bs, options, flags, errp); } static void qcow2_refresh_limits(BlockDriverState *bs, Error **errp) { BDRVQcow2State *s = bs->opaque; if (bs->encrypted) { /* Encryption works on a sector granularity */ bs->bl.request_alignment = BDRV_SECTOR_SIZE; } bs->bl.pwrite_zeroes_alignment = s->cluster_size; bs->bl.pdiscard_alignment = s->cluster_size; } static int qcow2_reopen_prepare(BDRVReopenState *state, BlockReopenQueue *queue, Error **errp) { Qcow2ReopenState *r; int ret; r = g_new0(Qcow2ReopenState, 1); state->opaque = r; ret = qcow2_update_options_prepare(state->bs, r, state->options, state->flags, errp); if (ret < 0) { goto fail; } /* We need to write out any unwritten data if we reopen read-only. */ if ((state->flags & BDRV_O_RDWR) == 0) { ret = bdrv_flush(state->bs); if (ret < 0) { goto fail; } ret = qcow2_mark_clean(state->bs); if (ret < 0) { goto fail; } } return 0; fail: qcow2_update_options_abort(state->bs, r); g_free(r); return ret; } static void qcow2_reopen_commit(BDRVReopenState *state) { qcow2_update_options_commit(state->bs, state->opaque); g_free(state->opaque); } static void qcow2_reopen_abort(BDRVReopenState *state) { qcow2_update_options_abort(state->bs, state->opaque); g_free(state->opaque); } static void qcow2_join_options(QDict *options, QDict *old_options) { bool has_new_overlap_template = qdict_haskey(options, QCOW2_OPT_OVERLAP) || qdict_haskey(options, QCOW2_OPT_OVERLAP_TEMPLATE); bool has_new_total_cache_size = qdict_haskey(options, QCOW2_OPT_CACHE_SIZE); bool has_all_cache_options; /* New overlap template overrides all old overlap options */ if (has_new_overlap_template) { qdict_del(old_options, QCOW2_OPT_OVERLAP); qdict_del(old_options, QCOW2_OPT_OVERLAP_TEMPLATE); qdict_del(old_options, QCOW2_OPT_OVERLAP_MAIN_HEADER); qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L1); qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L2); qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_TABLE); qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK); qdict_del(old_options, QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE); qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L1); qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L2); } /* New total cache size overrides all old options */ if (qdict_haskey(options, QCOW2_OPT_CACHE_SIZE)) { qdict_del(old_options, QCOW2_OPT_L2_CACHE_SIZE); qdict_del(old_options, QCOW2_OPT_REFCOUNT_CACHE_SIZE); } qdict_join(options, old_options, false); /* * If after merging all cache size options are set, an old total size is * overwritten. Do keep all options, however, if all three are new. The * resulting error message is what we want to happen. */ has_all_cache_options = qdict_haskey(options, QCOW2_OPT_CACHE_SIZE) || qdict_haskey(options, QCOW2_OPT_L2_CACHE_SIZE) || qdict_haskey(options, QCOW2_OPT_REFCOUNT_CACHE_SIZE); if (has_all_cache_options && !has_new_total_cache_size) { qdict_del(options, QCOW2_OPT_CACHE_SIZE); } } static int64_t coroutine_fn qcow2_co_get_block_status(BlockDriverState *bs, int64_t sector_num, int nb_sectors, int *pnum, BlockDriverState **file) { BDRVQcow2State *s = bs->opaque; uint64_t cluster_offset; int index_in_cluster, ret; unsigned int bytes; int64_t status = 0; bytes = MIN(INT_MAX, nb_sectors * BDRV_SECTOR_SIZE); qemu_co_mutex_lock(&s->lock); ret = qcow2_get_cluster_offset(bs, sector_num << 9, &bytes, &cluster_offset); qemu_co_mutex_unlock(&s->lock); if (ret < 0) { return ret; } *pnum = bytes >> BDRV_SECTOR_BITS; if (cluster_offset != 0 && ret != QCOW2_CLUSTER_COMPRESSED && !s->crypto) { index_in_cluster = sector_num & (s->cluster_sectors - 1); cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS); *file = bs->file->bs; status |= BDRV_BLOCK_OFFSET_VALID | cluster_offset; } if (ret == QCOW2_CLUSTER_ZERO_PLAIN || ret == QCOW2_CLUSTER_ZERO_ALLOC) { status |= BDRV_BLOCK_ZERO; } else if (ret != QCOW2_CLUSTER_UNALLOCATED) { status |= BDRV_BLOCK_DATA; } return status; } /* handle reading after the end of the backing file */ int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov, int64_t offset, int bytes) { uint64_t bs_size = bs->total_sectors * BDRV_SECTOR_SIZE; int n1; if ((offset + bytes) <= bs_size) { return bytes; } if (offset >= bs_size) { n1 = 0; } else { n1 = bs_size - offset; } qemu_iovec_memset(qiov, n1, 0, bytes - n1); return n1; } static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags) { BDRVQcow2State *s = bs->opaque; int offset_in_cluster, n1; int ret; unsigned int cur_bytes; /* number of bytes in current iteration */ uint64_t cluster_offset = 0; uint64_t bytes_done = 0; QEMUIOVector hd_qiov; uint8_t *cluster_data = NULL; qemu_iovec_init(&hd_qiov, qiov->niov); qemu_co_mutex_lock(&s->lock); while (bytes != 0) { /* prepare next request */ cur_bytes = MIN(bytes, INT_MAX); if (s->crypto) { cur_bytes = MIN(cur_bytes, QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); } ret = qcow2_get_cluster_offset(bs, offset, &cur_bytes, &cluster_offset); if (ret < 0) { goto fail; } offset_in_cluster = offset_into_cluster(s, offset); qemu_iovec_reset(&hd_qiov); qemu_iovec_concat(&hd_qiov, qiov, bytes_done, cur_bytes); switch (ret) { case QCOW2_CLUSTER_UNALLOCATED: if (bs->backing) { /* read from the base image */ n1 = qcow2_backing_read1(bs->backing->bs, &hd_qiov, offset, cur_bytes); if (n1 > 0) { QEMUIOVector local_qiov; qemu_iovec_init(&local_qiov, hd_qiov.niov); qemu_iovec_concat(&local_qiov, &hd_qiov, 0, n1); BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO); qemu_co_mutex_unlock(&s->lock); ret = bdrv_co_preadv(bs->backing, offset, n1, &local_qiov, 0); qemu_co_mutex_lock(&s->lock); qemu_iovec_destroy(&local_qiov); if (ret < 0) { goto fail; } } } else { /* Note: in this case, no need to wait */ qemu_iovec_memset(&hd_qiov, 0, 0, cur_bytes); } break; case QCOW2_CLUSTER_ZERO_PLAIN: case QCOW2_CLUSTER_ZERO_ALLOC: qemu_iovec_memset(&hd_qiov, 0, 0, cur_bytes); break; case QCOW2_CLUSTER_COMPRESSED: /* add AIO support for compressed blocks ? */ ret = qcow2_decompress_cluster(bs, cluster_offset); if (ret < 0) { goto fail; } qemu_iovec_from_buf(&hd_qiov, 0, s->cluster_cache + offset_in_cluster, cur_bytes); break; case QCOW2_CLUSTER_NORMAL: if ((cluster_offset & 511) != 0) { ret = -EIO; goto fail; } if (bs->encrypted) { assert(s->crypto); /* * For encrypted images, read everything into a temporary * contiguous buffer on which the AES functions can work. */ if (!cluster_data) { cluster_data = qemu_try_blockalign(bs->file->bs, QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); if (cluster_data == NULL) { ret = -ENOMEM; goto fail; } } assert(cur_bytes <= QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); qemu_iovec_reset(&hd_qiov); qemu_iovec_add(&hd_qiov, cluster_data, cur_bytes); } BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); qemu_co_mutex_unlock(&s->lock); ret = bdrv_co_preadv(bs->file, cluster_offset + offset_in_cluster, cur_bytes, &hd_qiov, 0); qemu_co_mutex_lock(&s->lock); if (ret < 0) { goto fail; } if (bs->encrypted) { assert(s->crypto); assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0); assert((cur_bytes & (BDRV_SECTOR_SIZE - 1)) == 0); Error *err = NULL; if (qcrypto_block_decrypt(s->crypto, (s->crypt_physical_offset ? cluster_offset + offset_in_cluster : offset) >> BDRV_SECTOR_BITS, cluster_data, cur_bytes, &err) < 0) { error_free(err); ret = -EIO; goto fail; } qemu_iovec_from_buf(qiov, bytes_done, cluster_data, cur_bytes); } break; default: g_assert_not_reached(); ret = -EIO; goto fail; } bytes -= cur_bytes; offset += cur_bytes; bytes_done += cur_bytes; } ret = 0; fail: qemu_co_mutex_unlock(&s->lock); qemu_iovec_destroy(&hd_qiov); qemu_vfree(cluster_data); return ret; } /* Check if it's possible to merge a write request with the writing of * the data from the COW regions */ static bool merge_cow(uint64_t offset, unsigned bytes, QEMUIOVector *hd_qiov, QCowL2Meta *l2meta) { QCowL2Meta *m; for (m = l2meta; m != NULL; m = m->next) { /* If both COW regions are empty then there's nothing to merge */ if (m->cow_start.nb_bytes == 0 && m->cow_end.nb_bytes == 0) { continue; } /* The data (middle) region must be immediately after the * start region */ if (l2meta_cow_start(m) + m->cow_start.nb_bytes != offset) { continue; } /* The end region must be immediately after the data (middle) * region */ if (m->offset + m->cow_end.offset != offset + bytes) { continue; } /* Make sure that adding both COW regions to the QEMUIOVector * does not exceed IOV_MAX */ if (hd_qiov->niov > IOV_MAX - 2) { continue; } m->data_qiov = hd_qiov; return true; } return false; } static coroutine_fn int qcow2_co_pwritev(BlockDriverState *bs, uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags) { BDRVQcow2State *s = bs->opaque; int offset_in_cluster; int ret; unsigned int cur_bytes; /* number of sectors in current iteration */ uint64_t cluster_offset; QEMUIOVector hd_qiov; uint64_t bytes_done = 0; uint8_t *cluster_data = NULL; QCowL2Meta *l2meta = NULL; trace_qcow2_writev_start_req(qemu_coroutine_self(), offset, bytes); qemu_iovec_init(&hd_qiov, qiov->niov); s->cluster_cache_offset = -1; /* disable compressed cache */ qemu_co_mutex_lock(&s->lock); while (bytes != 0) { l2meta = NULL; trace_qcow2_writev_start_part(qemu_coroutine_self()); offset_in_cluster = offset_into_cluster(s, offset); cur_bytes = MIN(bytes, INT_MAX); if (bs->encrypted) { cur_bytes = MIN(cur_bytes, QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size - offset_in_cluster); } ret = qcow2_alloc_cluster_offset(bs, offset, &cur_bytes, &cluster_offset, &l2meta); if (ret < 0) { goto fail; } assert((cluster_offset & 511) == 0); qemu_iovec_reset(&hd_qiov); qemu_iovec_concat(&hd_qiov, qiov, bytes_done, cur_bytes); if (bs->encrypted) { Error *err = NULL; assert(s->crypto); if (!cluster_data) { cluster_data = qemu_try_blockalign(bs->file->bs, QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); if (cluster_data == NULL) { ret = -ENOMEM; goto fail; } } assert(hd_qiov.size <= QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); qemu_iovec_to_buf(&hd_qiov, 0, cluster_data, hd_qiov.size); if (qcrypto_block_encrypt(s->crypto, (s->crypt_physical_offset ? cluster_offset + offset_in_cluster : offset) >> BDRV_SECTOR_BITS, cluster_data, cur_bytes, &err) < 0) { error_free(err); ret = -EIO; goto fail; } qemu_iovec_reset(&hd_qiov); qemu_iovec_add(&hd_qiov, cluster_data, cur_bytes); } ret = qcow2_pre_write_overlap_check(bs, 0, cluster_offset + offset_in_cluster, cur_bytes); if (ret < 0) { goto fail; } /* If we need to do COW, check if it's possible to merge the * writing of the guest data together with that of the COW regions. * If it's not possible (or not necessary) then write the * guest data now. */ if (!merge_cow(offset, cur_bytes, &hd_qiov, l2meta)) { qemu_co_mutex_unlock(&s->lock); BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); trace_qcow2_writev_data(qemu_coroutine_self(), cluster_offset + offset_in_cluster); ret = bdrv_co_pwritev(bs->file, cluster_offset + offset_in_cluster, cur_bytes, &hd_qiov, 0); qemu_co_mutex_lock(&s->lock); if (ret < 0) { goto fail; } } while (l2meta != NULL) { QCowL2Meta *next; ret = qcow2_alloc_cluster_link_l2(bs, l2meta); if (ret < 0) { goto fail; } /* Take the request off the list of running requests */ if (l2meta->nb_clusters != 0) { QLIST_REMOVE(l2meta, next_in_flight); } qemu_co_queue_restart_all(&l2meta->dependent_requests); next = l2meta->next; g_free(l2meta); l2meta = next; } bytes -= cur_bytes; offset += cur_bytes; bytes_done += cur_bytes; trace_qcow2_writev_done_part(qemu_coroutine_self(), cur_bytes); } ret = 0; fail: qemu_co_mutex_unlock(&s->lock); while (l2meta != NULL) { QCowL2Meta *next; if (l2meta->nb_clusters != 0) { QLIST_REMOVE(l2meta, next_in_flight); } qemu_co_queue_restart_all(&l2meta->dependent_requests); next = l2meta->next; g_free(l2meta); l2meta = next; } qemu_iovec_destroy(&hd_qiov); qemu_vfree(cluster_data); trace_qcow2_writev_done_req(qemu_coroutine_self(), ret); return ret; } static int qcow2_inactivate(BlockDriverState *bs) { BDRVQcow2State *s = bs->opaque; int ret, result = 0; ret = qcow2_cache_flush(bs, s->l2_table_cache); if (ret) { result = ret; error_report("Failed to flush the L2 table cache: %s", strerror(-ret)); } ret = qcow2_cache_flush(bs, s->refcount_block_cache); if (ret) { result = ret; error_report("Failed to flush the refcount block cache: %s", strerror(-ret)); } if (result == 0) { qcow2_mark_clean(bs); } return result; } static void qcow2_close(BlockDriverState *bs) { BDRVQcow2State *s = bs->opaque; qemu_vfree(s->l1_table); /* else pre-write overlap checks in cache_destroy may crash */ s->l1_table = NULL; if (!(s->flags & BDRV_O_INACTIVE)) { qcow2_inactivate(bs); } cache_clean_timer_del(bs); qcow2_cache_destroy(bs, s->l2_table_cache); qcow2_cache_destroy(bs, s->refcount_block_cache); qcrypto_block_free(s->crypto); s->crypto = NULL; g_free(s->unknown_header_fields); cleanup_unknown_header_ext(bs); g_free(s->image_backing_file); g_free(s->image_backing_format); g_free(s->cluster_cache); qemu_vfree(s->cluster_data); qcow2_refcount_close(bs); qcow2_free_snapshots(bs); } static void qcow2_invalidate_cache(BlockDriverState *bs, Error **errp) { BDRVQcow2State *s = bs->opaque; int flags = s->flags; QCryptoBlock *crypto = NULL; QDict *options; Error *local_err = NULL; int ret; /* * Backing files are read-only which makes all of their metadata immutable, * that means we don't have to worry about reopening them here. */ crypto = s->crypto; s->crypto = NULL; qcow2_close(bs); memset(s, 0, sizeof(BDRVQcow2State)); options = qdict_clone_shallow(bs->options); flags &= ~BDRV_O_INACTIVE; ret = qcow2_do_open(bs, options, flags, &local_err); QDECREF(options); if (local_err) { error_propagate(errp, local_err); error_prepend(errp, "Could not reopen qcow2 layer: "); bs->drv = NULL; return; } else if (ret < 0) { error_setg_errno(errp, -ret, "Could not reopen qcow2 layer"); bs->drv = NULL; return; } s->crypto = crypto; } static size_t header_ext_add(char *buf, uint32_t magic, const void *s, size_t len, size_t buflen) { QCowExtension *ext_backing_fmt = (QCowExtension*) buf; size_t ext_len = sizeof(QCowExtension) + ((len + 7) & ~7); if (buflen < ext_len) { return -ENOSPC; } *ext_backing_fmt = (QCowExtension) { .magic = cpu_to_be32(magic), .len = cpu_to_be32(len), }; if (len) { memcpy(buf + sizeof(QCowExtension), s, len); } return ext_len; } /* * Updates the qcow2 header, including the variable length parts of it, i.e. * the backing file name and all extensions. qcow2 was not designed to allow * such changes, so if we run out of space (we can only use the first cluster) * this function may fail. * * Returns 0 on success, -errno in error cases. */ int qcow2_update_header(BlockDriverState *bs) { BDRVQcow2State *s = bs->opaque; QCowHeader *header; char *buf; size_t buflen = s->cluster_size; int ret; uint64_t total_size; uint32_t refcount_table_clusters; size_t header_length; Qcow2UnknownHeaderExtension *uext; buf = qemu_blockalign(bs, buflen); /* Header structure */ header = (QCowHeader*) buf; if (buflen < sizeof(*header)) { ret = -ENOSPC; goto fail; } header_length = sizeof(*header) + s->unknown_header_fields_size; total_size = bs->total_sectors * BDRV_SECTOR_SIZE; refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3); *header = (QCowHeader) { /* Version 2 fields */ .magic = cpu_to_be32(QCOW_MAGIC), .version = cpu_to_be32(s->qcow_version), .backing_file_offset = 0, .backing_file_size = 0, .cluster_bits = cpu_to_be32(s->cluster_bits), .size = cpu_to_be64(total_size), .crypt_method = cpu_to_be32(s->crypt_method_header), .l1_size = cpu_to_be32(s->l1_size), .l1_table_offset = cpu_to_be64(s->l1_table_offset), .refcount_table_offset = cpu_to_be64(s->refcount_table_offset), .refcount_table_clusters = cpu_to_be32(refcount_table_clusters), .nb_snapshots = cpu_to_be32(s->nb_snapshots), .snapshots_offset = cpu_to_be64(s->snapshots_offset), /* Version 3 fields */ .incompatible_features = cpu_to_be64(s->incompatible_features), .compatible_features = cpu_to_be64(s->compatible_features), .autoclear_features = cpu_to_be64(s->autoclear_features), .refcount_order = cpu_to_be32(s->refcount_order), .header_length = cpu_to_be32(header_length), }; /* For older versions, write a shorter header */ switch (s->qcow_version) { case 2: ret = offsetof(QCowHeader, incompatible_features); break; case 3: ret = sizeof(*header); break; default: ret = -EINVAL; goto fail; } buf += ret; buflen -= ret; memset(buf, 0, buflen); /* Preserve any unknown field in the header */ if (s->unknown_header_fields_size) { if (buflen < s->unknown_header_fields_size) { ret = -ENOSPC; goto fail; } memcpy(buf, s->unknown_header_fields, s->unknown_header_fields_size); buf += s->unknown_header_fields_size; buflen -= s->unknown_header_fields_size; } /* Backing file format header extension */ if (s->image_backing_format) { ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BACKING_FORMAT, s->image_backing_format, strlen(s->image_backing_format), buflen); if (ret < 0) { goto fail; } buf += ret; buflen -= ret; } /* Full disk encryption header pointer extension */ if (s->crypto_header.offset != 0) { cpu_to_be64s(&s->crypto_header.offset); cpu_to_be64s(&s->crypto_header.length); ret = header_ext_add(buf, QCOW2_EXT_MAGIC_CRYPTO_HEADER, &s->crypto_header, sizeof(s->crypto_header), buflen); be64_to_cpus(&s->crypto_header.offset); be64_to_cpus(&s->crypto_header.length); if (ret < 0) { goto fail; } buf += ret; buflen -= ret; } /* Feature table */ if (s->qcow_version >= 3) { Qcow2Feature features[] = { { .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, .bit = QCOW2_INCOMPAT_DIRTY_BITNR, .name = "dirty bit", }, { .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, .bit = QCOW2_INCOMPAT_CORRUPT_BITNR, .name = "corrupt bit", }, { .type = QCOW2_FEAT_TYPE_COMPATIBLE, .bit = QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR, .name = "lazy refcounts", }, }; ret = header_ext_add(buf, QCOW2_EXT_MAGIC_FEATURE_TABLE, features, sizeof(features), buflen); if (ret < 0) { goto fail; } buf += ret; buflen -= ret; } /* Keep unknown header extensions */ QLIST_FOREACH(uext, &s->unknown_header_ext, next) { ret = header_ext_add(buf, uext->magic, uext->data, uext->len, buflen); if (ret < 0) { goto fail; } buf += ret; buflen -= ret; } /* End of header extensions */ ret = header_ext_add(buf, QCOW2_EXT_MAGIC_END, NULL, 0, buflen); if (ret < 0) { goto fail; } buf += ret; buflen -= ret; /* Backing file name */ if (s->image_backing_file) { size_t backing_file_len = strlen(s->image_backing_file); if (buflen < backing_file_len) { ret = -ENOSPC; goto fail; } /* Using strncpy is ok here, since buf is not NUL-terminated. */ strncpy(buf, s->image_backing_file, buflen); header->backing_file_offset = cpu_to_be64(buf - ((char*) header)); header->backing_file_size = cpu_to_be32(backing_file_len); } /* Write the new header */ ret = bdrv_pwrite(bs->file, 0, header, s->cluster_size); if (ret < 0) { goto fail; } ret = 0; fail: qemu_vfree(header); return ret; } static int qcow2_change_backing_file(BlockDriverState *bs, const char *backing_file, const char *backing_fmt) { BDRVQcow2State *s = bs->opaque; if (backing_file && strlen(backing_file) > 1023) { return -EINVAL; } pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: ""); pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: ""); g_free(s->image_backing_file); g_free(s->image_backing_format); s->image_backing_file = backing_file ? g_strdup(bs->backing_file) : NULL; s->image_backing_format = backing_fmt ? g_strdup(bs->backing_format) : NULL; return qcow2_update_header(bs); } static int qcow2_crypt_method_from_format(const char *encryptfmt) { if (g_str_equal(encryptfmt, "luks")) { return QCOW_CRYPT_LUKS; } else if (g_str_equal(encryptfmt, "aes")) { return QCOW_CRYPT_AES; } else { return -EINVAL; } } static int qcow2_set_up_encryption(BlockDriverState *bs, const char *encryptfmt, QemuOpts *opts, Error **errp) { BDRVQcow2State *s = bs->opaque; QCryptoBlockCreateOptions *cryptoopts = NULL; QCryptoBlock *crypto = NULL; int ret = -EINVAL; QDict *options, *encryptopts; int fmt; options = qemu_opts_to_qdict(opts, NULL); qdict_extract_subqdict(options, &encryptopts, "encrypt."); QDECREF(options); fmt = qcow2_crypt_method_from_format(encryptfmt); switch (fmt) { case QCOW_CRYPT_LUKS: cryptoopts = block_crypto_create_opts_init( Q_CRYPTO_BLOCK_FORMAT_LUKS, encryptopts, errp); break; case QCOW_CRYPT_AES: cryptoopts = block_crypto_create_opts_init( Q_CRYPTO_BLOCK_FORMAT_QCOW, encryptopts, errp); break; default: error_setg(errp, "Unknown encryption format '%s'", encryptfmt); break; } if (!cryptoopts) { ret = -EINVAL; goto out; } s->crypt_method_header = fmt; crypto = qcrypto_block_create(cryptoopts, qcow2_crypto_hdr_init_func, qcow2_crypto_hdr_write_func, bs, errp); if (!crypto) { ret = -EINVAL; goto out; } ret = qcow2_update_header(bs); if (ret < 0) { error_setg_errno(errp, -ret, "Could not write encryption header"); goto out; } out: QDECREF(encryptopts); qcrypto_block_free(crypto); qapi_free_QCryptoBlockCreateOptions(cryptoopts); return ret; } static int preallocate(BlockDriverState *bs) { uint64_t bytes; uint64_t offset; uint64_t host_offset = 0; unsigned int cur_bytes; int ret; QCowL2Meta *meta; bytes = bdrv_getlength(bs); offset = 0; while (bytes) { cur_bytes = MIN(bytes, INT_MAX); ret = qcow2_alloc_cluster_offset(bs, offset, &cur_bytes, &host_offset, &meta); if (ret < 0) { return ret; } while (meta) { QCowL2Meta *next = meta->next; ret = qcow2_alloc_cluster_link_l2(bs, meta); if (ret < 0) { qcow2_free_any_clusters(bs, meta->alloc_offset, meta->nb_clusters, QCOW2_DISCARD_NEVER); return ret; } /* There are no dependent requests, but we need to remove our * request from the list of in-flight requests */ QLIST_REMOVE(meta, next_in_flight); g_free(meta); meta = next; } /* TODO Preallocate data if requested */ bytes -= cur_bytes; offset += cur_bytes; } /* * It is expected that the image file is large enough to actually contain * all of the allocated clusters (otherwise we get failing reads after * EOF). Extend the image to the last allocated sector. */ if (host_offset != 0) { uint8_t data = 0; ret = bdrv_pwrite(bs->file, (host_offset + cur_bytes) - 1, &data, 1); if (ret < 0) { return ret; } } return 0; } static int qcow2_create2(const char *filename, int64_t total_size, const char *backing_file, const char *backing_format, int flags, size_t cluster_size, PreallocMode prealloc, QemuOpts *opts, int version, int refcount_order, const char *encryptfmt, Error **errp) { int cluster_bits; QDict *options; /* Calculate cluster_bits */ cluster_bits = ctz32(cluster_size); if (cluster_bits < MIN_CLUSTER_BITS || cluster_bits > MAX_CLUSTER_BITS || (1 << cluster_bits) != cluster_size) { error_setg(errp, "Cluster size must be a power of two between %d and " "%dk", 1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10)); return -EINVAL; } /* * Open the image file and write a minimal qcow2 header. * * We keep things simple and start with a zero-sized image. We also * do without refcount blocks or a L1 table for now. We'll fix the * inconsistency later. * * We do need a refcount table because growing the refcount table means * allocating two new refcount blocks - the seconds of which would be at * 2 GB for 64k clusters, and we don't want to have a 2 GB initial file * size for any qcow2 image. */ BlockBackend *blk; QCowHeader *header; uint64_t* refcount_table; Error *local_err = NULL; int ret; if (prealloc == PREALLOC_MODE_FULL || prealloc == PREALLOC_MODE_FALLOC) { /* Note: The following calculation does not need to be exact; if it is a * bit off, either some bytes will be "leaked" (which is fine) or we * will need to increase the file size by some bytes (which is fine, * too, as long as the bulk is allocated here). Therefore, using * floating point arithmetic is fine. */ int64_t meta_size = 0; uint64_t nreftablee, nrefblocke, nl1e, nl2e, refblock_count; int64_t aligned_total_size = align_offset(total_size, cluster_size); int refblock_bits, refblock_size; /* refcount entry size in bytes */ double rces = (1 << refcount_order) / 8.; /* see qcow2_open() */ refblock_bits = cluster_bits - (refcount_order - 3); refblock_size = 1 << refblock_bits; /* header: 1 cluster */ meta_size += cluster_size; /* total size of L2 tables */ nl2e = aligned_total_size / cluster_size; nl2e = align_offset(nl2e, cluster_size / sizeof(uint64_t)); meta_size += nl2e * sizeof(uint64_t); /* total size of L1 tables */ nl1e = nl2e * sizeof(uint64_t) / cluster_size; nl1e = align_offset(nl1e, cluster_size / sizeof(uint64_t)); meta_size += nl1e * sizeof(uint64_t); /* total size of refcount blocks * * note: every host cluster is reference-counted, including metadata * (even refcount blocks are recursively included). * Let: * a = total_size (this is the guest disk size) * m = meta size not including refcount blocks and refcount tables * c = cluster size * y1 = number of refcount blocks entries * y2 = meta size including everything * rces = refcount entry size in bytes * then, * y1 = (y2 + a)/c * y2 = y1 * rces + y1 * rces * sizeof(u64) / c + m * we can get y1: * y1 = (a + m) / (c - rces - rces * sizeof(u64) / c) */ nrefblocke = (aligned_total_size + meta_size + cluster_size) / (cluster_size - rces - rces * sizeof(uint64_t) / cluster_size); refblock_count = DIV_ROUND_UP(nrefblocke, refblock_size); meta_size += refblock_count * cluster_size; /* total size of refcount tables */ nreftablee = align_offset(refblock_count, cluster_size / sizeof(uint64_t)); meta_size += nreftablee * sizeof(uint64_t); qemu_opt_set_number(opts, BLOCK_OPT_SIZE, aligned_total_size + meta_size, &error_abort); qemu_opt_set(opts, BLOCK_OPT_PREALLOC, PreallocMode_lookup[prealloc], &error_abort); } ret = bdrv_create_file(filename, opts, &local_err); if (ret < 0) { error_propagate(errp, local_err); return ret; } blk = blk_new_open(filename, NULL, NULL, BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, &local_err); if (blk == NULL) { error_propagate(errp, local_err); return -EIO; } blk_set_allow_write_beyond_eof(blk, true); /* Write the header */ QEMU_BUILD_BUG_ON((1 << MIN_CLUSTER_BITS) < sizeof(*header)); header = g_malloc0(cluster_size); *header = (QCowHeader) { .magic = cpu_to_be32(QCOW_MAGIC), .version = cpu_to_be32(version), .cluster_bits = cpu_to_be32(cluster_bits), .size = cpu_to_be64(0), .l1_table_offset = cpu_to_be64(0), .l1_size = cpu_to_be32(0), .refcount_table_offset = cpu_to_be64(cluster_size), .refcount_table_clusters = cpu_to_be32(1), .refcount_order = cpu_to_be32(refcount_order), .header_length = cpu_to_be32(sizeof(*header)), }; /* We'll update this to correct value later */ header->crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); if (flags & BLOCK_FLAG_LAZY_REFCOUNTS) { header->compatible_features |= cpu_to_be64(QCOW2_COMPAT_LAZY_REFCOUNTS); } ret = blk_pwrite(blk, 0, header, cluster_size, 0); g_free(header); if (ret < 0) { error_setg_errno(errp, -ret, "Could not write qcow2 header"); goto out; } /* Write a refcount table with one refcount block */ refcount_table = g_malloc0(2 * cluster_size); refcount_table[0] = cpu_to_be64(2 * cluster_size); ret = blk_pwrite(blk, cluster_size, refcount_table, 2 * cluster_size, 0); g_free(refcount_table); if (ret < 0) { error_setg_errno(errp, -ret, "Could not write refcount table"); goto out; } blk_unref(blk); blk = NULL; /* * And now open the image and make it consistent first (i.e. increase the * refcount of the cluster that is occupied by the header and the refcount * table) */ options = qdict_new(); qdict_put_str(options, "driver", "qcow2"); blk = blk_new_open(filename, NULL, options, BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_NO_FLUSH, &local_err); if (blk == NULL) { error_propagate(errp, local_err); ret = -EIO; goto out; } ret = qcow2_alloc_clusters(blk_bs(blk), 3 * cluster_size); if (ret < 0) { error_setg_errno(errp, -ret, "Could not allocate clusters for qcow2 " "header and refcount table"); goto out; } else if (ret != 0) { error_report("Huh, first cluster in empty image is already in use?"); abort(); } /* Create a full header (including things like feature table) */ ret = qcow2_update_header(blk_bs(blk)); if (ret < 0) { error_setg_errno(errp, -ret, "Could not update qcow2 header"); goto out; } /* Okay, now that we have a valid image, let's give it the right size */ ret = blk_truncate(blk, total_size, errp); if (ret < 0) { error_prepend(errp, "Could not resize image: "); goto out; } /* Want a backing file? There you go.*/ if (backing_file) { ret = bdrv_change_backing_file(blk_bs(blk), backing_file, backing_format); if (ret < 0) { error_setg_errno(errp, -ret, "Could not assign backing file '%s' " "with format '%s'", backing_file, backing_format); goto out; } } /* Want encryption? There you go. */ if (encryptfmt) { ret = qcow2_set_up_encryption(blk_bs(blk), encryptfmt, opts, errp); if (ret < 0) { goto out; } } /* And if we're supposed to preallocate metadata, do that now */ if (prealloc != PREALLOC_MODE_OFF) { BDRVQcow2State *s = blk_bs(blk)->opaque; qemu_co_mutex_lock(&s->lock); ret = preallocate(blk_bs(blk)); qemu_co_mutex_unlock(&s->lock); if (ret < 0) { error_setg_errno(errp, -ret, "Could not preallocate metadata"); goto out; } } blk_unref(blk); blk = NULL; /* Reopen the image without BDRV_O_NO_FLUSH to flush it before returning. * Using BDRV_O_NO_IO, since encryption is now setup we don't want to * have to setup decryption context. We're not doing any I/O on the top * level BlockDriverState, only lower layers, where BDRV_O_NO_IO does * not have effect. */ options = qdict_new(); qdict_put_str(options, "driver", "qcow2"); blk = blk_new_open(filename, NULL, options, BDRV_O_RDWR | BDRV_O_NO_BACKING | BDRV_O_NO_IO, &local_err); if (blk == NULL) { error_propagate(errp, local_err); ret = -EIO; goto out; } ret = 0; out: if (blk) { blk_unref(blk); } return ret; } static int qcow2_create(const char *filename, QemuOpts *opts, Error **errp) { char *backing_file = NULL; char *backing_fmt = NULL; char *buf = NULL; uint64_t size = 0; int flags = 0; size_t cluster_size = DEFAULT_CLUSTER_SIZE; PreallocMode prealloc; int version = 3; uint64_t refcount_bits = 16; int refcount_order; const char *encryptfmt = NULL; Error *local_err = NULL; int ret; /* Read out options */ size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0), BDRV_SECTOR_SIZE); backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT); encryptfmt = qemu_opt_get_del(opts, BLOCK_OPT_ENCRYPT_FORMAT); if (encryptfmt) { if (qemu_opt_get_del(opts, BLOCK_OPT_ENCRYPT)) { error_setg(errp, "Options " BLOCK_OPT_ENCRYPT " and " BLOCK_OPT_ENCRYPT_FORMAT " are mutually exclusive"); ret = -EINVAL; goto finish; } } else if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) { encryptfmt = "aes"; } cluster_size = qemu_opt_get_size_del(opts, BLOCK_OPT_CLUSTER_SIZE, DEFAULT_CLUSTER_SIZE); buf = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC); prealloc = qapi_enum_parse(PreallocMode_lookup, buf, PREALLOC_MODE__MAX, PREALLOC_MODE_OFF, &local_err); if (local_err) { error_propagate(errp, local_err); ret = -EINVAL; goto finish; } g_free(buf); buf = qemu_opt_get_del(opts, BLOCK_OPT_COMPAT_LEVEL); if (!buf) { /* keep the default */ } else if (!strcmp(buf, "0.10")) { version = 2; } else if (!strcmp(buf, "1.1")) { version = 3; } else { error_setg(errp, "Invalid compatibility level: '%s'", buf); ret = -EINVAL; goto finish; } if (qemu_opt_get_bool_del(opts, BLOCK_OPT_LAZY_REFCOUNTS, false)) { flags |= BLOCK_FLAG_LAZY_REFCOUNTS; } if (backing_file && prealloc != PREALLOC_MODE_OFF) { error_setg(errp, "Backing file and preallocation cannot be used at " "the same time"); ret = -EINVAL; goto finish; } if (version < 3 && (flags & BLOCK_FLAG_LAZY_REFCOUNTS)) { error_setg(errp, "Lazy refcounts only supported with compatibility " "level 1.1 and above (use compat=1.1 or greater)"); ret = -EINVAL; goto finish; } refcount_bits = qemu_opt_get_number_del(opts, BLOCK_OPT_REFCOUNT_BITS, refcount_bits); if (refcount_bits > 64 || !is_power_of_2(refcount_bits)) { error_setg(errp, "Refcount width must be a power of two and may not " "exceed 64 bits"); ret = -EINVAL; goto finish; } if (version < 3 && refcount_bits != 16) { error_setg(errp, "Different refcount widths than 16 bits require " "compatibility level 1.1 or above (use compat=1.1 or " "greater)"); ret = -EINVAL; goto finish; } refcount_order = ctz32(refcount_bits); ret = qcow2_create2(filename, size, backing_file, backing_fmt, flags, cluster_size, prealloc, opts, version, refcount_order, encryptfmt, &local_err); error_propagate(errp, local_err); finish: g_free(backing_file); g_free(backing_fmt); g_free(buf); return ret; } static bool is_zero_sectors(BlockDriverState *bs, int64_t start, uint32_t count) { int nr; BlockDriverState *file; int64_t res; if (start + count > bs->total_sectors) { count = bs->total_sectors - start; } if (!count) { return true; } res = bdrv_get_block_status_above(bs, NULL, start, count, &nr, &file); return res >= 0 && (res & BDRV_BLOCK_ZERO) && nr == count; } static coroutine_fn int qcow2_co_pwrite_zeroes(BlockDriverState *bs, int64_t offset, int bytes, BdrvRequestFlags flags) { int ret; BDRVQcow2State *s = bs->opaque; uint32_t head = offset % s->cluster_size; uint32_t tail = (offset + bytes) % s->cluster_size; trace_qcow2_pwrite_zeroes_start_req(qemu_coroutine_self(), offset, bytes); if (offset + bytes == bs->total_sectors * BDRV_SECTOR_SIZE) { tail = 0; } if (head || tail) { int64_t cl_start = (offset - head) >> BDRV_SECTOR_BITS; uint64_t off; unsigned int nr; assert(head + bytes <= s->cluster_size); /* check whether remainder of cluster already reads as zero */ if (!(is_zero_sectors(bs, cl_start, DIV_ROUND_UP(head, BDRV_SECTOR_SIZE)) && is_zero_sectors(bs, (offset + bytes) >> BDRV_SECTOR_BITS, DIV_ROUND_UP(-tail & (s->cluster_size - 1), BDRV_SECTOR_SIZE)))) { return -ENOTSUP; } qemu_co_mutex_lock(&s->lock); /* We can have new write after previous check */ offset = cl_start << BDRV_SECTOR_BITS; bytes = s->cluster_size; nr = s->cluster_size; ret = qcow2_get_cluster_offset(bs, offset, &nr, &off); if (ret != QCOW2_CLUSTER_UNALLOCATED && ret != QCOW2_CLUSTER_ZERO_PLAIN && ret != QCOW2_CLUSTER_ZERO_ALLOC) { qemu_co_mutex_unlock(&s->lock); return -ENOTSUP; } } else { qemu_co_mutex_lock(&s->lock); } trace_qcow2_pwrite_zeroes(qemu_coroutine_self(), offset, bytes); /* Whatever is left can use real zero clusters */ ret = qcow2_cluster_zeroize(bs, offset, bytes, flags); qemu_co_mutex_unlock(&s->lock); return ret; } static coroutine_fn int qcow2_co_pdiscard(BlockDriverState *bs, int64_t offset, int bytes) { int ret; BDRVQcow2State *s = bs->opaque; if (!QEMU_IS_ALIGNED(offset | bytes, s->cluster_size)) { assert(bytes < s->cluster_size); /* Ignore partial clusters, except for the special case of the * complete partial cluster at the end of an unaligned file */ if (!QEMU_IS_ALIGNED(offset, s->cluster_size) || offset + bytes != bs->total_sectors * BDRV_SECTOR_SIZE) { return -ENOTSUP; } } qemu_co_mutex_lock(&s->lock); ret = qcow2_cluster_discard(bs, offset, bytes, QCOW2_DISCARD_REQUEST, false); qemu_co_mutex_unlock(&s->lock); return ret; } static int qcow2_truncate(BlockDriverState *bs, int64_t offset, Error **errp) { BDRVQcow2State *s = bs->opaque; int64_t new_l1_size; int ret; if (offset & 511) { error_setg(errp, "The new size must be a multiple of 512"); return -EINVAL; } /* cannot proceed if image has snapshots */ if (s->nb_snapshots) { error_setg(errp, "Can't resize an image which has snapshots"); return -ENOTSUP; } /* shrinking is currently not supported */ if (offset < bs->total_sectors * 512) { error_setg(errp, "qcow2 doesn't support shrinking images yet"); return -ENOTSUP; } new_l1_size = size_to_l1(s, offset); ret = qcow2_grow_l1_table(bs, new_l1_size, true); if (ret < 0) { error_setg_errno(errp, -ret, "Failed to grow the L1 table"); return ret; } /* write updated header.size */ offset = cpu_to_be64(offset); ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, size), &offset, sizeof(uint64_t)); if (ret < 0) { error_setg_errno(errp, -ret, "Failed to update the image size"); return ret; } s->l1_vm_state_index = new_l1_size; return 0; } /* XXX: put compressed sectors first, then all the cluster aligned tables to avoid losing bytes in alignment */ static coroutine_fn int qcow2_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset, uint64_t bytes, QEMUIOVector *qiov) { BDRVQcow2State *s = bs->opaque; QEMUIOVector hd_qiov; struct iovec iov; z_stream strm; int ret, out_len; uint8_t *buf, *out_buf; uint64_t cluster_offset; if (bytes == 0) { /* align end of file to a sector boundary to ease reading with sector based I/Os */ cluster_offset = bdrv_getlength(bs->file->bs); return bdrv_truncate(bs->file, cluster_offset, NULL); } buf = qemu_blockalign(bs, s->cluster_size); if (bytes != s->cluster_size) { if (bytes > s->cluster_size || offset + bytes != bs->total_sectors << BDRV_SECTOR_BITS) { qemu_vfree(buf); return -EINVAL; } /* Zero-pad last write if image size is not cluster aligned */ memset(buf + bytes, 0, s->cluster_size - bytes); } qemu_iovec_to_buf(qiov, 0, buf, bytes); out_buf = g_malloc(s->cluster_size); /* 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) { ret = -EINVAL; goto fail; } 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) { deflateEnd(&strm); ret = -EINVAL; goto fail; } 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 */ ret = qcow2_co_pwritev(bs, offset, bytes, qiov, 0); if (ret < 0) { goto fail; } goto success; } qemu_co_mutex_lock(&s->lock); cluster_offset = qcow2_alloc_compressed_cluster_offset(bs, offset, out_len); if (!cluster_offset) { qemu_co_mutex_unlock(&s->lock); ret = -EIO; goto fail; } cluster_offset &= s->cluster_offset_mask; ret = qcow2_pre_write_overlap_check(bs, 0, cluster_offset, out_len); qemu_co_mutex_unlock(&s->lock); if (ret < 0) { goto fail; } iov = (struct iovec) { .iov_base = out_buf, .iov_len = out_len, }; qemu_iovec_init_external(&hd_qiov, &iov, 1); BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED); ret = bdrv_co_pwritev(bs->file, cluster_offset, out_len, &hd_qiov, 0); if (ret < 0) { goto fail; } success: ret = 0; fail: qemu_vfree(buf); g_free(out_buf); return ret; } static int make_completely_empty(BlockDriverState *bs) { BDRVQcow2State *s = bs->opaque; Error *local_err = NULL; int ret, l1_clusters; int64_t offset; uint64_t *new_reftable = NULL; uint64_t rt_entry, l1_size2; struct { uint64_t l1_offset; uint64_t reftable_offset; uint32_t reftable_clusters; } QEMU_PACKED l1_ofs_rt_ofs_cls; ret = qcow2_cache_empty(bs, s->l2_table_cache); if (ret < 0) { goto fail; } ret = qcow2_cache_empty(bs, s->refcount_block_cache); if (ret < 0) { goto fail; } /* Refcounts will be broken utterly */ ret = qcow2_mark_dirty(bs); if (ret < 0) { goto fail; } BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); l1_size2 = (uint64_t)s->l1_size * sizeof(uint64_t); /* After this call, neither the in-memory nor the on-disk refcount * information accurately describe the actual references */ ret = bdrv_pwrite_zeroes(bs->file, s->l1_table_offset, l1_clusters * s->cluster_size, 0); if (ret < 0) { goto fail_broken_refcounts; } memset(s->l1_table, 0, l1_size2); BLKDBG_EVENT(bs->file, BLKDBG_EMPTY_IMAGE_PREPARE); /* Overwrite enough clusters at the beginning of the sectors to place * the refcount table, a refcount block and the L1 table in; this may * overwrite parts of the existing refcount and L1 table, which is not * an issue because the dirty flag is set, complete data loss is in fact * desired and partial data loss is consequently fine as well */ ret = bdrv_pwrite_zeroes(bs->file, s->cluster_size, (2 + l1_clusters) * s->cluster_size, 0); /* This call (even if it failed overall) may have overwritten on-disk * refcount structures; in that case, the in-memory refcount information * will probably differ from the on-disk information which makes the BDS * unusable */ if (ret < 0) { goto fail_broken_refcounts; } BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_UPDATE); /* "Create" an empty reftable (one cluster) directly after the image * header and an empty L1 table three clusters after the image header; * the cluster between those two will be used as the first refblock */ l1_ofs_rt_ofs_cls.l1_offset = cpu_to_be64(3 * s->cluster_size); l1_ofs_rt_ofs_cls.reftable_offset = cpu_to_be64(s->cluster_size); l1_ofs_rt_ofs_cls.reftable_clusters = cpu_to_be32(1); ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, l1_table_offset), &l1_ofs_rt_ofs_cls, sizeof(l1_ofs_rt_ofs_cls)); if (ret < 0) { goto fail_broken_refcounts; } s->l1_table_offset = 3 * s->cluster_size; new_reftable = g_try_new0(uint64_t, s->cluster_size / sizeof(uint64_t)); if (!new_reftable) { ret = -ENOMEM; goto fail_broken_refcounts; } s->refcount_table_offset = s->cluster_size; s->refcount_table_size = s->cluster_size / sizeof(uint64_t); s->max_refcount_table_index = 0; g_free(s->refcount_table); s->refcount_table = new_reftable; new_reftable = NULL; /* Now the in-memory refcount information again corresponds to the on-disk * information (reftable is empty and no refblocks (the refblock cache is * empty)); however, this means some clusters (e.g. the image header) are * referenced, but not refcounted, but the normal qcow2 code assumes that * the in-memory information is always correct */ BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC); /* Enter the first refblock into the reftable */ rt_entry = cpu_to_be64(2 * s->cluster_size); ret = bdrv_pwrite_sync(bs->file, s->cluster_size, &rt_entry, sizeof(rt_entry)); if (ret < 0) { goto fail_broken_refcounts; } s->refcount_table[0] = 2 * s->cluster_size; s->free_cluster_index = 0; assert(3 + l1_clusters <= s->refcount_block_size); offset = qcow2_alloc_clusters(bs, 3 * s->cluster_size + l1_size2); if (offset < 0) { ret = offset; goto fail_broken_refcounts; } else if (offset > 0) { error_report("First cluster in emptied image is in use"); abort(); } /* Now finally the in-memory information corresponds to the on-disk * structures and is correct */ ret = qcow2_mark_clean(bs); if (ret < 0) { goto fail; } ret = bdrv_truncate(bs->file, (3 + l1_clusters) * s->cluster_size, &local_err); if (ret < 0) { error_report_err(local_err); goto fail; } return 0; fail_broken_refcounts: /* The BDS is unusable at this point. If we wanted to make it usable, we * would have to call qcow2_refcount_close(), qcow2_refcount_init(), * qcow2_check_refcounts(), qcow2_refcount_close() and qcow2_refcount_init() * again. However, because the functions which could have caused this error * path to be taken are used by those functions as well, it's very likely * that that sequence will fail as well. Therefore, just eject the BDS. */ bs->drv = NULL; fail: g_free(new_reftable); return ret; } static int qcow2_make_empty(BlockDriverState *bs) { BDRVQcow2State *s = bs->opaque; uint64_t offset, end_offset; int step = QEMU_ALIGN_DOWN(INT_MAX, s->cluster_size); int l1_clusters, ret = 0; l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); if (s->qcow_version >= 3 && !s->snapshots && 3 + l1_clusters <= s->refcount_block_size) { /* The following function only works for qcow2 v3 images (it requires * the dirty flag) and only as long as there are no snapshots (because * it completely empties the image). Furthermore, the L1 table and three * additional clusters (image header, refcount table, one refcount * block) have to fit inside one refcount block. */ return make_completely_empty(bs); } /* This fallback code simply discards every active cluster; this is slow, * but works in all cases */ end_offset = bs->total_sectors * BDRV_SECTOR_SIZE; for (offset = 0; offset < end_offset; offset += step) { /* As this function is generally used after committing an external * snapshot, QCOW2_DISCARD_SNAPSHOT seems appropriate. Also, the * default action for this kind of discard is to pass the discard, * which will ideally result in an actually smaller image file, as * is probably desired. */ ret = qcow2_cluster_discard(bs, offset, MIN(step, end_offset - offset), QCOW2_DISCARD_SNAPSHOT, true); if (ret < 0) { break; } } return ret; } static coroutine_fn int qcow2_co_flush_to_os(BlockDriverState *bs) { BDRVQcow2State *s = bs->opaque; int ret; qemu_co_mutex_lock(&s->lock); ret = qcow2_cache_write(bs, s->l2_table_cache); if (ret < 0) { qemu_co_mutex_unlock(&s->lock); return ret; } if (qcow2_need_accurate_refcounts(s)) { ret = qcow2_cache_write(bs, s->refcount_block_cache); if (ret < 0) { qemu_co_mutex_unlock(&s->lock); return ret; } } qemu_co_mutex_unlock(&s->lock); return 0; } static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) { BDRVQcow2State *s = bs->opaque; bdi->unallocated_blocks_are_zero = true; bdi->can_write_zeroes_with_unmap = (s->qcow_version >= 3); bdi->cluster_size = s->cluster_size; bdi->vm_state_offset = qcow2_vm_state_offset(s); return 0; } static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs) { BDRVQcow2State *s = bs->opaque; ImageInfoSpecific *spec_info = g_new(ImageInfoSpecific, 1); *spec_info = (ImageInfoSpecific){ .type = IMAGE_INFO_SPECIFIC_KIND_QCOW2, .u.qcow2.data = g_new(ImageInfoSpecificQCow2, 1), }; if (s->qcow_version == 2) { *spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){ .compat = g_strdup("0.10"), .refcount_bits = s->refcount_bits, }; } else if (s->qcow_version == 3) { *spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){ .compat = g_strdup("1.1"), .lazy_refcounts = s->compatible_features & QCOW2_COMPAT_LAZY_REFCOUNTS, .has_lazy_refcounts = true, .corrupt = s->incompatible_features & QCOW2_INCOMPAT_CORRUPT, .has_corrupt = true, .refcount_bits = s->refcount_bits, }; } else { /* if this assertion fails, this probably means a new version was * added without having it covered here */ assert(false); } return spec_info; } #if 0 static void dump_refcounts(BlockDriverState *bs) { BDRVQcow2State *s = bs->opaque; int64_t nb_clusters, k, k1, size; int refcount; size = bdrv_getlength(bs->file->bs); 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("%" PRId64 ": refcount=%d nb=%" PRId64 "\n", k, refcount, k - k1); } } #endif static int qcow2_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos) { BDRVQcow2State *s = bs->opaque; BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE); return bs->drv->bdrv_co_pwritev(bs, qcow2_vm_state_offset(s) + pos, qiov->size, qiov, 0); } static int qcow2_load_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos) { BDRVQcow2State *s = bs->opaque; BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD); return bs->drv->bdrv_co_preadv(bs, qcow2_vm_state_offset(s) + pos, qiov->size, qiov, 0); } /* * Downgrades an image's version. To achieve this, any incompatible features * have to be removed. */ static int qcow2_downgrade(BlockDriverState *bs, int target_version, BlockDriverAmendStatusCB *status_cb, void *cb_opaque) { BDRVQcow2State *s = bs->opaque; int current_version = s->qcow_version; int ret; if (target_version == current_version) { return 0; } else if (target_version > current_version) { return -EINVAL; } else if (target_version != 2) { return -EINVAL; } if (s->refcount_order != 4) { error_report("compat=0.10 requires refcount_bits=16"); return -ENOTSUP; } /* clear incompatible features */ if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { ret = qcow2_mark_clean(bs); if (ret < 0) { return ret; } } /* with QCOW2_INCOMPAT_CORRUPT, it is pretty much impossible to get here in * the first place; if that happens nonetheless, returning -ENOTSUP is the * best thing to do anyway */ if (s->incompatible_features) { return -ENOTSUP; } /* since we can ignore compatible features, we can set them to 0 as well */ s->compatible_features = 0; /* if lazy refcounts have been used, they have already been fixed through * clearing the dirty flag */ /* clearing autoclear features is trivial */ s->autoclear_features = 0; ret = qcow2_expand_zero_clusters(bs, status_cb, cb_opaque); if (ret < 0) { return ret; } s->qcow_version = target_version; ret = qcow2_update_header(bs); if (ret < 0) { s->qcow_version = current_version; return ret; } return 0; } typedef enum Qcow2AmendOperation { /* This is the value Qcow2AmendHelperCBInfo::last_operation will be * statically initialized to so that the helper CB can discern the first * invocation from an operation change */ QCOW2_NO_OPERATION = 0, QCOW2_CHANGING_REFCOUNT_ORDER, QCOW2_DOWNGRADING, } Qcow2AmendOperation; typedef struct Qcow2AmendHelperCBInfo { /* The code coordinating the amend operations should only modify * these four fields; the rest will be managed by the CB */ BlockDriverAmendStatusCB *original_status_cb; void *original_cb_opaque; Qcow2AmendOperation current_operation; /* Total number of operations to perform (only set once) */ int total_operations; /* The following fields are managed by the CB */ /* Number of operations completed */ int operations_completed; /* Cumulative offset of all completed operations */ int64_t offset_completed; Qcow2AmendOperation last_operation; int64_t last_work_size; } Qcow2AmendHelperCBInfo; static void qcow2_amend_helper_cb(BlockDriverState *bs, int64_t operation_offset, int64_t operation_work_size, void *opaque) { Qcow2AmendHelperCBInfo *info = opaque; int64_t current_work_size; int64_t projected_work_size; if (info->current_operation != info->last_operation) { if (info->last_operation != QCOW2_NO_OPERATION) { info->offset_completed += info->last_work_size; info->operations_completed++; } info->last_operation = info->current_operation; } assert(info->total_operations > 0); assert(info->operations_completed < info->total_operations); info->last_work_size = operation_work_size; current_work_size = info->offset_completed + operation_work_size; /* current_work_size is the total work size for (operations_completed + 1) * operations (which includes this one), so multiply it by the number of * operations not covered and divide it by the number of operations * covered to get a projection for the operations not covered */ projected_work_size = current_work_size * (info->total_operations - info->operations_completed - 1) / (info->operations_completed + 1); info->original_status_cb(bs, info->offset_completed + operation_offset, current_work_size + projected_work_size, info->original_cb_opaque); } static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts, BlockDriverAmendStatusCB *status_cb, void *cb_opaque) { BDRVQcow2State *s = bs->opaque; int old_version = s->qcow_version, new_version = old_version; uint64_t new_size = 0; const char *backing_file = NULL, *backing_format = NULL; bool lazy_refcounts = s->use_lazy_refcounts; const char *compat = NULL; uint64_t cluster_size = s->cluster_size; bool encrypt; int encformat; int refcount_bits = s->refcount_bits; Error *local_err = NULL; int ret; QemuOptDesc *desc = opts->list->desc; Qcow2AmendHelperCBInfo helper_cb_info; while (desc && desc->name) { if (!qemu_opt_find(opts, desc->name)) { /* only change explicitly defined options */ desc++; continue; } if (!strcmp(desc->name, BLOCK_OPT_COMPAT_LEVEL)) { compat = qemu_opt_get(opts, BLOCK_OPT_COMPAT_LEVEL); if (!compat) { /* preserve default */ } else if (!strcmp(compat, "0.10")) { new_version = 2; } else if (!strcmp(compat, "1.1")) { new_version = 3; } else { error_report("Unknown compatibility level %s", compat); return -EINVAL; } } else if (!strcmp(desc->name, BLOCK_OPT_PREALLOC)) { error_report("Cannot change preallocation mode"); return -ENOTSUP; } else if (!strcmp(desc->name, BLOCK_OPT_SIZE)) { new_size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0); } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FILE)) { backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE); } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FMT)) { backing_format = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT); } else if (!strcmp(desc->name, BLOCK_OPT_ENCRYPT)) { encrypt = qemu_opt_get_bool(opts, BLOCK_OPT_ENCRYPT, !!s->crypto); if (encrypt != !!s->crypto) { error_report("Changing the encryption flag is not supported"); return -ENOTSUP; } } else if (!strcmp(desc->name, BLOCK_OPT_ENCRYPT_FORMAT)) { encformat = qcow2_crypt_method_from_format( qemu_opt_get(opts, BLOCK_OPT_ENCRYPT_FORMAT)); if (encformat != s->crypt_method_header) { error_report("Changing the encryption format is not supported"); return -ENOTSUP; } } else if (!strcmp(desc->name, BLOCK_OPT_CLUSTER_SIZE)) { cluster_size = qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE, cluster_size); if (cluster_size != s->cluster_size) { error_report("Changing the cluster size is not supported"); return -ENOTSUP; } } else if (!strcmp(desc->name, BLOCK_OPT_LAZY_REFCOUNTS)) { lazy_refcounts = qemu_opt_get_bool(opts, BLOCK_OPT_LAZY_REFCOUNTS, lazy_refcounts); } else if (!strcmp(desc->name, BLOCK_OPT_REFCOUNT_BITS)) { refcount_bits = qemu_opt_get_number(opts, BLOCK_OPT_REFCOUNT_BITS, refcount_bits); if (refcount_bits <= 0 || refcount_bits > 64 || !is_power_of_2(refcount_bits)) { error_report("Refcount width must be a power of two and may " "not exceed 64 bits"); return -EINVAL; } } else { /* if this point is reached, this probably means a new option was * added without having it covered here */ abort(); } desc++; } helper_cb_info = (Qcow2AmendHelperCBInfo){ .original_status_cb = status_cb, .original_cb_opaque = cb_opaque, .total_operations = (new_version < old_version) + (s->refcount_bits != refcount_bits) }; /* Upgrade first (some features may require compat=1.1) */ if (new_version > old_version) { s->qcow_version = new_version; ret = qcow2_update_header(bs); if (ret < 0) { s->qcow_version = old_version; return ret; } } if (s->refcount_bits != refcount_bits) { int refcount_order = ctz32(refcount_bits); if (new_version < 3 && refcount_bits != 16) { error_report("Different refcount widths than 16 bits require " "compatibility level 1.1 or above (use compat=1.1 or " "greater)"); return -EINVAL; } helper_cb_info.current_operation = QCOW2_CHANGING_REFCOUNT_ORDER; ret = qcow2_change_refcount_order(bs, refcount_order, &qcow2_amend_helper_cb, &helper_cb_info, &local_err); if (ret < 0) { error_report_err(local_err); return ret; } } if (backing_file || backing_format) { ret = qcow2_change_backing_file(bs, backing_file ?: s->image_backing_file, backing_format ?: s->image_backing_format); if (ret < 0) { return ret; } } if (s->use_lazy_refcounts != lazy_refcounts) { if (lazy_refcounts) { if (new_version < 3) { error_report("Lazy refcounts only supported with compatibility " "level 1.1 and above (use compat=1.1 or greater)"); return -EINVAL; } s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; ret = qcow2_update_header(bs); if (ret < 0) { s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; return ret; } s->use_lazy_refcounts = true; } else { /* make image clean first */ ret = qcow2_mark_clean(bs); if (ret < 0) { return ret; } /* now disallow lazy refcounts */ s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; ret = qcow2_update_header(bs); if (ret < 0) { s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; return ret; } s->use_lazy_refcounts = false; } } if (new_size) { BlockBackend *blk = blk_new(BLK_PERM_RESIZE, BLK_PERM_ALL); ret = blk_insert_bs(blk, bs, &local_err); if (ret < 0) { error_report_err(local_err); blk_unref(blk); return ret; } ret = blk_truncate(blk, new_size, &local_err); blk_unref(blk); if (ret < 0) { error_report_err(local_err); return ret; } } /* Downgrade last (so unsupported features can be removed before) */ if (new_version < old_version) { helper_cb_info.current_operation = QCOW2_DOWNGRADING; ret = qcow2_downgrade(bs, new_version, &qcow2_amend_helper_cb, &helper_cb_info); if (ret < 0) { return ret; } } return 0; } /* * If offset or size are negative, respectively, they will not be included in * the BLOCK_IMAGE_CORRUPTED event emitted. * fatal will be ignored for read-only BDS; corruptions found there will always * be considered non-fatal. */ void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset, int64_t size, const char *message_format, ...) { BDRVQcow2State *s = bs->opaque; const char *node_name; char *message; va_list ap; fatal = fatal && !bs->read_only; if (s->signaled_corruption && (!fatal || (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT))) { return; } va_start(ap, message_format); message = g_strdup_vprintf(message_format, ap); va_end(ap); if (fatal) { fprintf(stderr, "qcow2: Marking image as corrupt: %s; further " "corruption events will be suppressed\n", message); } else { fprintf(stderr, "qcow2: Image is corrupt: %s; further non-fatal " "corruption events will be suppressed\n", message); } node_name = bdrv_get_node_name(bs); qapi_event_send_block_image_corrupted(bdrv_get_device_name(bs), *node_name != '\0', node_name, message, offset >= 0, offset, size >= 0, size, fatal, &error_abort); g_free(message); if (fatal) { qcow2_mark_corrupt(bs); bs->drv = NULL; /* make BDS unusable */ } s->signaled_corruption = true; } static QemuOptsList qcow2_create_opts = { .name = "qcow2-create-opts", .head = QTAILQ_HEAD_INITIALIZER(qcow2_create_opts.head), .desc = { { .name = BLOCK_OPT_SIZE, .type = QEMU_OPT_SIZE, .help = "Virtual disk size" }, { .name = BLOCK_OPT_COMPAT_LEVEL, .type = QEMU_OPT_STRING, .help = "Compatibility level (0.10 or 1.1)" }, { .name = BLOCK_OPT_BACKING_FILE, .type = QEMU_OPT_STRING, .help = "File name of a base image" }, { .name = BLOCK_OPT_BACKING_FMT, .type = QEMU_OPT_STRING, .help = "Image format of the base image" }, { .name = BLOCK_OPT_ENCRYPT, .type = QEMU_OPT_BOOL, .help = "Encrypt the image with format 'aes'. (Deprecated " "in favor of " BLOCK_OPT_ENCRYPT_FORMAT "=aes)", }, { .name = BLOCK_OPT_ENCRYPT_FORMAT, .type = QEMU_OPT_STRING, .help = "Encrypt the image, format choices: 'aes', 'luks'", }, BLOCK_CRYPTO_OPT_DEF_KEY_SECRET("encrypt.", "ID of secret providing qcow AES key or LUKS passphrase"), BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_ALG("encrypt."), BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_MODE("encrypt."), BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_ALG("encrypt."), BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_HASH_ALG("encrypt."), BLOCK_CRYPTO_OPT_DEF_LUKS_HASH_ALG("encrypt."), BLOCK_CRYPTO_OPT_DEF_LUKS_ITER_TIME("encrypt."), { .name = BLOCK_OPT_CLUSTER_SIZE, .type = QEMU_OPT_SIZE, .help = "qcow2 cluster size", .def_value_str = stringify(DEFAULT_CLUSTER_SIZE) }, { .name = BLOCK_OPT_PREALLOC, .type = QEMU_OPT_STRING, .help = "Preallocation mode (allowed values: off, metadata, " "falloc, full)" }, { .name = BLOCK_OPT_LAZY_REFCOUNTS, .type = QEMU_OPT_BOOL, .help = "Postpone refcount updates", .def_value_str = "off" }, { .name = BLOCK_OPT_REFCOUNT_BITS, .type = QEMU_OPT_NUMBER, .help = "Width of a reference count entry in bits", .def_value_str = "16" }, { /* end of list */ } } }; BlockDriver bdrv_qcow2 = { .format_name = "qcow2", .instance_size = sizeof(BDRVQcow2State), .bdrv_probe = qcow2_probe, .bdrv_open = qcow2_open, .bdrv_close = qcow2_close, .bdrv_reopen_prepare = qcow2_reopen_prepare, .bdrv_reopen_commit = qcow2_reopen_commit, .bdrv_reopen_abort = qcow2_reopen_abort, .bdrv_join_options = qcow2_join_options, .bdrv_child_perm = bdrv_format_default_perms, .bdrv_create = qcow2_create, .bdrv_has_zero_init = bdrv_has_zero_init_1, .bdrv_co_get_block_status = qcow2_co_get_block_status, .bdrv_co_preadv = qcow2_co_preadv, .bdrv_co_pwritev = qcow2_co_pwritev, .bdrv_co_flush_to_os = qcow2_co_flush_to_os, .bdrv_co_pwrite_zeroes = qcow2_co_pwrite_zeroes, .bdrv_co_pdiscard = qcow2_co_pdiscard, .bdrv_truncate = qcow2_truncate, .bdrv_co_pwritev_compressed = qcow2_co_pwritev_compressed, .bdrv_make_empty = qcow2_make_empty, .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_snapshot_load_tmp = qcow2_snapshot_load_tmp, .bdrv_get_info = qcow2_get_info, .bdrv_get_specific_info = qcow2_get_specific_info, .bdrv_save_vmstate = qcow2_save_vmstate, .bdrv_load_vmstate = qcow2_load_vmstate, .supports_backing = true, .bdrv_change_backing_file = qcow2_change_backing_file, .bdrv_refresh_limits = qcow2_refresh_limits, .bdrv_invalidate_cache = qcow2_invalidate_cache, .bdrv_inactivate = qcow2_inactivate, .create_opts = &qcow2_create_opts, .bdrv_check = qcow2_check, .bdrv_amend_options = qcow2_amend_options, .bdrv_detach_aio_context = qcow2_detach_aio_context, .bdrv_attach_aio_context = qcow2_attach_aio_context, }; static void bdrv_qcow2_init(void) { bdrv_register(&bdrv_qcow2); } block_init(bdrv_qcow2_init);