diff options
Diffstat (limited to 'src/block/qcow2.c')
| -rw-r--r-- | src/block/qcow2.c | 3193 |
1 files changed, 3193 insertions, 0 deletions
diff --git a/src/block/qcow2.c b/src/block/qcow2.c new file mode 100644 index 0000000..88f56c8 --- /dev/null +++ b/src/block/qcow2.c @@ -0,0 +1,3193 @@ +/* + * Block driver for the QCOW version 2 format + * + * Copyright (c) 2004-2006 Fabrice Bellard + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ +#include "qemu-common.h" +#include "block/block_int.h" +#include "qemu/module.h" +#include <zlib.h> +#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" + +/* + 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 + +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; +} + + +/* + * 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, + 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->bs, 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->bs, 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->bs, 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; + + 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->bs, 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 GCC_FMT_ATTR(3, 4) report_unsupported(BlockDriverState *bs, + Error **errp, const char *fmt, ...) +{ + char msg[64]; + va_list ap; + + va_start(ap, fmt); + vsnprintf(msg, sizeof(msg), fmt, ap); + va_end(ap); + + error_setg(errp, QERR_UNKNOWN_BLOCK_FORMAT_FEATURE, + bdrv_get_device_or_node_name(bs), "qcow2", msg); +} + +static void report_unsupported_feature(BlockDriverState *bs, + 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); + } + + report_unsupported(bs, errp, "%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->bs, 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 & (s->cluster_size - 1)) { + 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)", + }, + { /* 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; +} 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; + Error *local_err = NULL; + int ret; + + 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); + 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); + + ret = 0; +fail: + 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)); + } +} + +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); + } +} + +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_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->bs, 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) { + report_unsupported(bs, errp, "QCOW 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->bs, 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, NULL); + report_unsupported_feature(bs, 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; + + if (header.crypt_method > QCOW_CRYPT_AES) { + error_setg(errp, "Unsupported encryption method: %" PRIu32, + header.crypt_method); + ret = -EINVAL; + goto fail; + } + if (!qcrypto_cipher_supports(QCRYPTO_CIPHER_ALG_AES_128)) { + error_setg(errp, "AES cipher not available"); + ret = -EINVAL; + goto fail; + } + s->crypt_method_header = header.crypt_method; + if (s->crypt_method_header) { + bs->encrypted = 1; + } + + 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->bs, 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, + &local_err)) { + error_propagate(errp, local_err); + 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->bs, 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_INCOMING) && 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); + + /* Repair image if dirty */ + if (!(flags & (BDRV_O_CHECK | BDRV_O_INCOMING)) && !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); + return ret; +} + +static void qcow2_refresh_limits(BlockDriverState *bs, Error **errp) +{ + BDRVQcow2State *s = bs->opaque; + + bs->bl.write_zeroes_alignment = s->cluster_sectors; +} + +static int qcow2_set_key(BlockDriverState *bs, const char *key) +{ + BDRVQcow2State *s = bs->opaque; + uint8_t keybuf[16]; + int len, i; + Error *err = NULL; + + memset(keybuf, 0, 16); + len = strlen(key); + if (len > 16) + len = 16; + /* XXX: we could compress the chars to 7 bits to increase + entropy */ + for(i = 0;i < len;i++) { + keybuf[i] = key[i]; + } + assert(bs->encrypted); + + qcrypto_cipher_free(s->cipher); + s->cipher = qcrypto_cipher_new( + QCRYPTO_CIPHER_ALG_AES_128, + QCRYPTO_CIPHER_MODE_CBC, + keybuf, G_N_ELEMENTS(keybuf), + &err); + + if (!s->cipher) { + /* XXX would be nice if errors in this method could + * be properly propagate to the caller. Would need + * the bdrv_set_key() API signature to be fixed. */ + error_free(err); + return -1; + } + return 0; +} + +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 int64_t coroutine_fn qcow2_co_get_block_status(BlockDriverState *bs, + int64_t sector_num, int nb_sectors, int *pnum) +{ + BDRVQcow2State *s = bs->opaque; + uint64_t cluster_offset; + int index_in_cluster, ret; + int64_t status = 0; + + *pnum = nb_sectors; + qemu_co_mutex_lock(&s->lock); + ret = qcow2_get_cluster_offset(bs, sector_num << 9, pnum, &cluster_offset); + qemu_co_mutex_unlock(&s->lock); + if (ret < 0) { + return ret; + } + + if (cluster_offset != 0 && ret != QCOW2_CLUSTER_COMPRESSED && + !s->cipher) { + index_in_cluster = sector_num & (s->cluster_sectors - 1); + cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS); + status |= BDRV_BLOCK_OFFSET_VALID | cluster_offset; + } + if (ret == QCOW2_CLUSTER_ZERO) { + 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 sector_num, int nb_sectors) +{ + int n1; + if ((sector_num + nb_sectors) <= bs->total_sectors) + return nb_sectors; + if (sector_num >= bs->total_sectors) + n1 = 0; + else + n1 = bs->total_sectors - sector_num; + + qemu_iovec_memset(qiov, 512 * n1, 0, 512 * (nb_sectors - n1)); + + return n1; +} + +static coroutine_fn int qcow2_co_readv(BlockDriverState *bs, int64_t sector_num, + int remaining_sectors, QEMUIOVector *qiov) +{ + BDRVQcow2State *s = bs->opaque; + int index_in_cluster, n1; + int ret; + int cur_nr_sectors; /* number of sectors 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 (remaining_sectors != 0) { + + /* prepare next request */ + cur_nr_sectors = remaining_sectors; + if (s->cipher) { + cur_nr_sectors = MIN(cur_nr_sectors, + QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors); + } + + ret = qcow2_get_cluster_offset(bs, sector_num << 9, + &cur_nr_sectors, &cluster_offset); + if (ret < 0) { + goto fail; + } + + index_in_cluster = sector_num & (s->cluster_sectors - 1); + + qemu_iovec_reset(&hd_qiov); + qemu_iovec_concat(&hd_qiov, qiov, bytes_done, + cur_nr_sectors * 512); + + switch (ret) { + case QCOW2_CLUSTER_UNALLOCATED: + + if (bs->backing) { + /* read from the base image */ + n1 = qcow2_backing_read1(bs->backing->bs, &hd_qiov, + sector_num, cur_nr_sectors); + if (n1 > 0) { + QEMUIOVector local_qiov; + + qemu_iovec_init(&local_qiov, hd_qiov.niov); + qemu_iovec_concat(&local_qiov, &hd_qiov, 0, + n1 * BDRV_SECTOR_SIZE); + + BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO); + qemu_co_mutex_unlock(&s->lock); + ret = bdrv_co_readv(bs->backing->bs, sector_num, + n1, &local_qiov); + 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, 512 * cur_nr_sectors); + } + break; + + case QCOW2_CLUSTER_ZERO: + qemu_iovec_memset(&hd_qiov, 0, 0, 512 * cur_nr_sectors); + 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 + index_in_cluster * 512, + 512 * cur_nr_sectors); + break; + + case QCOW2_CLUSTER_NORMAL: + if ((cluster_offset & 511) != 0) { + ret = -EIO; + goto fail; + } + + if (bs->encrypted) { + assert(s->cipher); + + /* + * 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_nr_sectors <= + QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors); + qemu_iovec_reset(&hd_qiov); + qemu_iovec_add(&hd_qiov, cluster_data, + 512 * cur_nr_sectors); + } + + BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); + qemu_co_mutex_unlock(&s->lock); + ret = bdrv_co_readv(bs->file->bs, + (cluster_offset >> 9) + index_in_cluster, + cur_nr_sectors, &hd_qiov); + qemu_co_mutex_lock(&s->lock); + if (ret < 0) { + goto fail; + } + if (bs->encrypted) { + assert(s->cipher); + Error *err = NULL; + if (qcow2_encrypt_sectors(s, sector_num, cluster_data, + cluster_data, cur_nr_sectors, false, + &err) < 0) { + error_free(err); + ret = -EIO; + goto fail; + } + qemu_iovec_from_buf(qiov, bytes_done, + cluster_data, 512 * cur_nr_sectors); + } + break; + + default: + g_assert_not_reached(); + ret = -EIO; + goto fail; + } + + remaining_sectors -= cur_nr_sectors; + sector_num += cur_nr_sectors; + bytes_done += cur_nr_sectors * 512; + } + ret = 0; + +fail: + qemu_co_mutex_unlock(&s->lock); + + qemu_iovec_destroy(&hd_qiov); + qemu_vfree(cluster_data); + + return ret; +} + +static coroutine_fn int qcow2_co_writev(BlockDriverState *bs, + int64_t sector_num, + int remaining_sectors, + QEMUIOVector *qiov) +{ + BDRVQcow2State *s = bs->opaque; + int index_in_cluster; + int ret; + int cur_nr_sectors; /* 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(), sector_num, + remaining_sectors); + + qemu_iovec_init(&hd_qiov, qiov->niov); + + s->cluster_cache_offset = -1; /* disable compressed cache */ + + qemu_co_mutex_lock(&s->lock); + + while (remaining_sectors != 0) { + + l2meta = NULL; + + trace_qcow2_writev_start_part(qemu_coroutine_self()); + index_in_cluster = sector_num & (s->cluster_sectors - 1); + cur_nr_sectors = remaining_sectors; + if (bs->encrypted && + cur_nr_sectors > + QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors - index_in_cluster) { + cur_nr_sectors = + QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors - index_in_cluster; + } + + ret = qcow2_alloc_cluster_offset(bs, sector_num << 9, + &cur_nr_sectors, &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_nr_sectors * 512); + + if (bs->encrypted) { + Error *err = NULL; + assert(s->cipher); + 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 (qcow2_encrypt_sectors(s, sector_num, cluster_data, + cluster_data, cur_nr_sectors, + true, &err) < 0) { + error_free(err); + ret = -EIO; + goto fail; + } + + qemu_iovec_reset(&hd_qiov); + qemu_iovec_add(&hd_qiov, cluster_data, + cur_nr_sectors * 512); + } + + ret = qcow2_pre_write_overlap_check(bs, 0, + cluster_offset + index_in_cluster * BDRV_SECTOR_SIZE, + cur_nr_sectors * BDRV_SECTOR_SIZE); + if (ret < 0) { + goto fail; + } + + qemu_co_mutex_unlock(&s->lock); + BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); + trace_qcow2_writev_data(qemu_coroutine_self(), + (cluster_offset >> 9) + index_in_cluster); + ret = bdrv_co_writev(bs->file->bs, + (cluster_offset >> 9) + index_in_cluster, + cur_nr_sectors, &hd_qiov); + 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; + } + + remaining_sectors -= cur_nr_sectors; + sector_num += cur_nr_sectors; + bytes_done += cur_nr_sectors * 512; + trace_qcow2_writev_done_part(qemu_coroutine_self(), cur_nr_sectors); + } + 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 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 (!(bs->open_flags & BDRV_O_INCOMING)) { + int ret1, ret2; + + ret1 = qcow2_cache_flush(bs, s->l2_table_cache); + ret2 = qcow2_cache_flush(bs, s->refcount_block_cache); + + if (ret1) { + error_report("Failed to flush the L2 table cache: %s", + strerror(-ret1)); + } + if (ret2) { + error_report("Failed to flush the refcount block cache: %s", + strerror(-ret2)); + } + + if (!ret1 && !ret2) { + qcow2_mark_clean(bs); + } + } + + cache_clean_timer_del(bs); + qcow2_cache_destroy(bs, s->l2_table_cache); + qcow2_cache_destroy(bs, s->refcount_block_cache); + + qcrypto_cipher_free(s->cipher); + s->cipher = 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; + QCryptoCipher *cipher = 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. + */ + + cipher = s->cipher; + s->cipher = NULL; + + qcow2_close(bs); + + bdrv_invalidate_cache(bs->file->bs, &local_err); + if (local_err) { + error_propagate(errp, local_err); + return; + } + + memset(s, 0, sizeof(BDRVQcow2State)); + options = qdict_clone_shallow(bs->options); + + ret = qcow2_open(bs, options, flags, &local_err); + QDECREF(options); + if (local_err) { + error_setg(errp, "Could not reopen qcow2 layer: %s", + error_get_pretty(local_err)); + error_free(local_err); + return; + } else if (ret < 0) { + error_setg_errno(errp, -ret, "Could not reopen qcow2 layer"); + return; + } + + s->cipher = cipher; +} + +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), + }; + 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; + } + + /* Feature table */ + 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->bs, 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; + + 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 preallocate(BlockDriverState *bs) +{ + uint64_t nb_sectors; + uint64_t offset; + uint64_t host_offset = 0; + int num; + int ret; + QCowL2Meta *meta; + + nb_sectors = bdrv_nb_sectors(bs); + offset = 0; + + while (nb_sectors) { + num = MIN(nb_sectors, INT_MAX >> BDRV_SECTOR_BITS); + ret = qcow2_alloc_cluster_offset(bs, offset, &num, + &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 */ + + nb_sectors -= num; + offset += num << BDRV_SECTOR_BITS; + } + + /* + * 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 buf[BDRV_SECTOR_SIZE]; + memset(buf, 0, BDRV_SECTOR_SIZE); + ret = bdrv_write(bs->file->bs, + (host_offset >> BDRV_SECTOR_BITS) + num - 1, + buf, 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, + 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. + */ + BlockDriverState* bs; + 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; + 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); + meta_size += DIV_ROUND_UP(nrefblocke, refblock_size) * cluster_size; + + /* total size of refcount tables */ + nreftablee = nrefblocke / refblock_size; + nreftablee = align_offset(nreftablee, 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; + } + + bs = NULL; + ret = bdrv_open(&bs, filename, NULL, NULL, BDRV_O_RDWR | BDRV_O_PROTOCOL, + &local_err); + if (ret < 0) { + error_propagate(errp, local_err); + return ret; + } + + /* 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)), + }; + + if (flags & BLOCK_FLAG_ENCRYPT) { + header->crypt_method = cpu_to_be32(QCOW_CRYPT_AES); + } else { + 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 = bdrv_pwrite(bs, 0, header, cluster_size); + 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 = bdrv_pwrite(bs, cluster_size, refcount_table, 2 * cluster_size); + g_free(refcount_table); + + if (ret < 0) { + error_setg_errno(errp, -ret, "Could not write refcount table"); + goto out; + } + + bdrv_unref(bs); + bs = 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(options, "driver", qstring_from_str("qcow2")); + ret = bdrv_open(&bs, filename, NULL, options, + BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_NO_FLUSH, + &local_err); + if (ret < 0) { + error_propagate(errp, local_err); + goto out; + } + + ret = qcow2_alloc_clusters(bs, 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(); + } + + /* Okay, now that we have a valid image, let's give it the right size */ + ret = bdrv_truncate(bs, total_size); + if (ret < 0) { + error_setg_errno(errp, -ret, "Could not resize image"); + goto out; + } + + /* Want a backing file? There you go.*/ + if (backing_file) { + ret = bdrv_change_backing_file(bs, 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; + } + } + + /* And if we're supposed to preallocate metadata, do that now */ + if (prealloc != PREALLOC_MODE_OFF) { + BDRVQcow2State *s = bs->opaque; + qemu_co_mutex_lock(&s->lock); + ret = preallocate(bs); + qemu_co_mutex_unlock(&s->lock); + if (ret < 0) { + error_setg_errno(errp, -ret, "Could not preallocate metadata"); + goto out; + } + } + + bdrv_unref(bs); + bs = NULL; + + /* Reopen the image without BDRV_O_NO_FLUSH to flush it before returning */ + options = qdict_new(); + qdict_put(options, "driver", qstring_from_str("qcow2")); + ret = bdrv_open(&bs, filename, NULL, options, + BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_NO_BACKING, + &local_err); + if (local_err) { + error_propagate(errp, local_err); + goto out; + } + + ret = 0; +out: + if (bs) { + bdrv_unref(bs); + } + 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; + 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); + if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) { + flags |= BLOCK_FLAG_ENCRYPT; + } + 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, + &local_err); + if (local_err) { + error_propagate(errp, local_err); + } + +finish: + g_free(backing_file); + g_free(backing_fmt); + g_free(buf); + return ret; +} + +static coroutine_fn int qcow2_co_write_zeroes(BlockDriverState *bs, + int64_t sector_num, int nb_sectors, BdrvRequestFlags flags) +{ + int ret; + BDRVQcow2State *s = bs->opaque; + + /* Emulate misaligned zero writes */ + if (sector_num % s->cluster_sectors || nb_sectors % s->cluster_sectors) { + return -ENOTSUP; + } + + /* Whatever is left can use real zero clusters */ + qemu_co_mutex_lock(&s->lock); + ret = qcow2_zero_clusters(bs, sector_num << BDRV_SECTOR_BITS, + nb_sectors); + qemu_co_mutex_unlock(&s->lock); + + return ret; +} + +static coroutine_fn int qcow2_co_discard(BlockDriverState *bs, + int64_t sector_num, int nb_sectors) +{ + int ret; + BDRVQcow2State *s = bs->opaque; + + qemu_co_mutex_lock(&s->lock); + ret = qcow2_discard_clusters(bs, sector_num << BDRV_SECTOR_BITS, + nb_sectors, QCOW2_DISCARD_REQUEST, false); + qemu_co_mutex_unlock(&s->lock); + return ret; +} + +static int qcow2_truncate(BlockDriverState *bs, int64_t offset) +{ + BDRVQcow2State *s = bs->opaque; + int64_t new_l1_size; + int ret; + + if (offset & 511) { + error_report("The new size must be a multiple of 512"); + return -EINVAL; + } + + /* cannot proceed if image has snapshots */ + if (s->nb_snapshots) { + error_report("Can't resize an image which has snapshots"); + return -ENOTSUP; + } + + /* shrinking is currently not supported */ + if (offset < bs->total_sectors * 512) { + error_report("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) { + return ret; + } + + /* write updated header.size */ + offset = cpu_to_be64(offset); + ret = bdrv_pwrite_sync(bs->file->bs, offsetof(QCowHeader, size), + &offset, sizeof(uint64_t)); + if (ret < 0) { + 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 int qcow2_write_compressed(BlockDriverState *bs, int64_t sector_num, + const uint8_t *buf, int nb_sectors) +{ + BDRVQcow2State *s = bs->opaque; + z_stream strm; + int ret, out_len; + uint8_t *out_buf; + uint64_t cluster_offset; + + if (nb_sectors == 0) { + /* align end of file to a sector boundary to ease reading with + sector based I/Os */ + cluster_offset = bdrv_getlength(bs->file->bs); + return bdrv_truncate(bs->file->bs, cluster_offset); + } + + if (nb_sectors != s->cluster_sectors) { + ret = -EINVAL; + + /* Zero-pad last write if image size is not cluster aligned */ + if (sector_num + nb_sectors == bs->total_sectors && + nb_sectors < s->cluster_sectors) { + uint8_t *pad_buf = qemu_blockalign(bs, s->cluster_size); + memset(pad_buf, 0, s->cluster_size); + memcpy(pad_buf, buf, nb_sectors * BDRV_SECTOR_SIZE); + ret = qcow2_write_compressed(bs, sector_num, + pad_buf, s->cluster_sectors); + qemu_vfree(pad_buf); + } + return ret; + } + + out_buf = g_malloc(s->cluster_size + (s->cluster_size / 1000) + 128); + + /* best compression, small window, no zlib header */ + memset(&strm, 0, sizeof(strm)); + ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, + Z_DEFLATED, -12, + 9, Z_DEFAULT_STRATEGY); + if (ret != 0) { + 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 = bdrv_write(bs, sector_num, buf, s->cluster_sectors); + if (ret < 0) { + goto fail; + } + } else { + cluster_offset = qcow2_alloc_compressed_cluster_offset(bs, + sector_num << 9, out_len); + if (!cluster_offset) { + ret = -EIO; + goto fail; + } + cluster_offset &= s->cluster_offset_mask; + + ret = qcow2_pre_write_overlap_check(bs, 0, cluster_offset, out_len); + if (ret < 0) { + goto fail; + } + + BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED); + ret = bdrv_pwrite(bs->file->bs, cluster_offset, out_buf, out_len); + if (ret < 0) { + goto fail; + } + } + + ret = 0; +fail: + g_free(out_buf); + return ret; +} + +static int make_completely_empty(BlockDriverState *bs) +{ + BDRVQcow2State *s = bs->opaque; + 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_write_zeroes(bs->file->bs, s->l1_table_offset / BDRV_SECTOR_SIZE, + l1_clusters * s->cluster_sectors, 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_write_zeroes(bs->file->bs, s->cluster_size / BDRV_SECTOR_SIZE, + (2 + l1_clusters) * s->cluster_size / + BDRV_SECTOR_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 */ + cpu_to_be64w(&l1_ofs_rt_ofs_cls.l1_offset, 3 * s->cluster_size); + cpu_to_be64w(&l1_ofs_rt_ofs_cls.reftable_offset, s->cluster_size); + cpu_to_be32w(&l1_ofs_rt_ofs_cls.reftable_clusters, 1); + ret = bdrv_pwrite_sync(bs->file->bs, 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); + + 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->bs, 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->bs, (3 + l1_clusters) * s->cluster_size); + if (ret < 0) { + 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 start_sector; + int sector_step = INT_MAX / BDRV_SECTOR_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 */ + for (start_sector = 0; start_sector < bs->total_sectors; + start_sector += sector_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_discard_clusters(bs, start_sector * BDRV_SECTOR_SIZE, + MIN(sector_step, + bs->total_sectors - start_sector), + 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_flush(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_flush(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 = g_new(ImageInfoSpecificQCow2, 1), + }; + if (s->qcow_version == 2) { + *spec_info->u.qcow2 = (ImageInfoSpecificQCow2){ + .compat = g_strdup("0.10"), + .refcount_bits = s->refcount_bits, + }; + } else if (s->qcow_version == 3) { + *spec_info->u.qcow2 = (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, + }; + } + + 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; + int64_t total_sectors = bs->total_sectors; + bool zero_beyond_eof = bs->zero_beyond_eof; + int ret; + + BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE); + bs->zero_beyond_eof = false; + ret = bdrv_pwritev(bs, qcow2_vm_state_offset(s) + pos, qiov); + bs->zero_beyond_eof = zero_beyond_eof; + + /* bdrv_co_do_writev will have increased the total_sectors value to include + * the VM state - the VM state is however not an actual part of the block + * device, therefore, we need to restore the old value. */ + bs->total_sectors = total_sectors; + + return ret; +} + +static int qcow2_load_vmstate(BlockDriverState *bs, uint8_t *buf, + int64_t pos, int size) +{ + BDRVQcow2State *s = bs->opaque; + bool zero_beyond_eof = bs->zero_beyond_eof; + int ret; + + BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD); + bs->zero_beyond_eof = false; + ret = bdrv_pread(bs, qcow2_vm_state_offset(s) + pos, buf, size); + bs->zero_beyond_eof = zero_beyond_eof; + + return ret; +} + +/* + * 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) +{ + 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) { + /* we would have to convert the image to a refcount_order == 4 image + * here; however, since qemu (at the time of writing this) does not + * support anything different than 4 anyway, there is no point in doing + * so right now; however, we should error out (if qemu supports this in + * the future and this code has not been adapted) */ + error_report("qcow2_downgrade: Image refcount orders other than 4 are " + "currently not supported."); + 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); + 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; +} + +static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts, + BlockDriverAmendStatusCB *status_cb) +{ + 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 ret; + QemuOptDesc *desc = opts->list->desc; + + 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 { + fprintf(stderr, "Unknown compatibility level %s.\n", compat); + return -EINVAL; + } + } else if (!strcmp(desc->name, BLOCK_OPT_PREALLOC)) { + fprintf(stderr, "Cannot change preallocation mode.\n"); + 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->cipher); + + if (encrypt != !!s->cipher) { + fprintf(stderr, "Changing the encryption flag is not " + "supported.\n"); + 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) { + fprintf(stderr, "Changing the cluster size is not " + "supported.\n"); + 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)) { + error_report("Cannot change refcount entry width"); + return -ENOTSUP; + } else { + /* if this assertion fails, this probably means a new option was + * added without having it covered here */ + assert(false); + } + + desc++; + } + + if (new_version != old_version) { + if (new_version > old_version) { + /* Upgrade */ + s->qcow_version = new_version; + ret = qcow2_update_header(bs); + if (ret < 0) { + s->qcow_version = old_version; + return ret; + } + } else { + ret = qcow2_downgrade(bs, new_version, status_cb); + if (ret < 0) { + 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 (s->qcow_version < 3) { + fprintf(stderr, "Lazy refcounts only supported with compatibility " + "level 1.1 and above (use compat=1.1 or greater)\n"); + 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) { + ret = bdrv_truncate(bs, new_size); + 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", + .def_value_str = "off" + }, + { + .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_create = qcow2_create, + .bdrv_has_zero_init = bdrv_has_zero_init_1, + .bdrv_co_get_block_status = qcow2_co_get_block_status, + .bdrv_set_key = qcow2_set_key, + + .bdrv_co_readv = qcow2_co_readv, + .bdrv_co_writev = qcow2_co_writev, + .bdrv_co_flush_to_os = qcow2_co_flush_to_os, + + .bdrv_co_write_zeroes = qcow2_co_write_zeroes, + .bdrv_co_discard = qcow2_co_discard, + .bdrv_truncate = qcow2_truncate, + .bdrv_write_compressed = qcow2_write_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, + + .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); |
