diff options
Diffstat (limited to 'block/qcow2.c')
| -rw-r--r-- | block/qcow2.c | 6032 |
1 files changed, 6032 insertions, 0 deletions
diff --git a/block/qcow2.c b/block/qcow2.c new file mode 100644 index 000000000..d50901675 --- /dev/null +++ b/block/qcow2.c @@ -0,0 +1,6032 @@ +/* + * 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/qdict.h" +#include "sysemu/block-backend.h" +#include "qemu/main-loop.h" +#include "qemu/module.h" +#include "qcow2.h" +#include "qemu/error-report.h" +#include "qapi/error.h" +#include "qapi/qapi-events-block-core.h" +#include "qapi/qmp/qdict.h" +#include "qapi/qmp/qstring.h" +#include "trace.h" +#include "qemu/option_int.h" +#include "qemu/cutils.h" +#include "qemu/bswap.h" +#include "qapi/qobject-input-visitor.h" +#include "qapi/qapi-visit-block-core.h" +#include "crypto.h" +#include "block/aio_task.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 +#define QCOW2_EXT_MAGIC_BITMAPS 0x23852875 +#define QCOW2_EXT_MAGIC_DATA_FILE 0x44415441 + +static int coroutine_fn +qcow2_co_preadv_compressed(BlockDriverState *bs, + uint64_t l2_entry, + uint64_t offset, + uint64_t bytes, + QEMUIOVector *qiov, + size_t qiov_offset); + +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 all space in cluster so it has predictable + * content, as we may not initialize some regions of the + * header (eg only 1 out of 8 key slots will be initialized) + */ + clusterlen = size_to_clusters(s, headerlen) * s->cluster_size; + assert(qcow2_pre_write_overlap_check(bs, 0, ret, clusterlen, false) == 0); + ret = bdrv_pwrite_zeroes(bs->file, + ret, + clusterlen, 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; +} + +static QDict* +qcow2_extract_crypto_opts(QemuOpts *opts, const char *fmt, Error **errp) +{ + QDict *cryptoopts_qdict; + QDict *opts_qdict; + + /* Extract "encrypt." options into a qdict */ + opts_qdict = qemu_opts_to_qdict(opts, NULL); + qdict_extract_subqdict(opts_qdict, &cryptoopts_qdict, "encrypt."); + qobject_unref(opts_qdict); + qdict_put_str(cryptoopts_qdict, "format", fmt); + return cryptoopts_qdict; +} + +/* + * 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, bool *need_update_header, + Error **errp) +{ + BDRVQcow2State *s = bs->opaque; + QCowExtension ext; + uint64_t offset; + int ret; + Qcow2BitmapHeaderExt bitmaps_ext; + + if (need_update_header != NULL) { + *need_update_header = false; + } + +#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; + } + ext.magic = be32_to_cpu(ext.magic); + ext.len = be32_to_cpu(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; + } + s->crypto_header.offset = be64_to_cpu(s->crypto_header.offset); + s->crypto_header.length = be64_to_cpu(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, "encrypt.", + qcow2_crypto_hdr_read_func, + bs, cflags, QCOW2_MAX_THREADS, errp); + if (!s->crypto) { + return -EINVAL; + } + } break; + + case QCOW2_EXT_MAGIC_BITMAPS: + if (ext.len != sizeof(bitmaps_ext)) { + error_setg_errno(errp, -ret, "bitmaps_ext: " + "Invalid extension length"); + return -EINVAL; + } + + if (!(s->autoclear_features & QCOW2_AUTOCLEAR_BITMAPS)) { + if (s->qcow_version < 3) { + /* Let's be a bit more specific */ + warn_report("This qcow2 v2 image contains bitmaps, but " + "they may have been modified by a program " + "without persistent bitmap support; so now " + "they must all be considered inconsistent"); + } else { + warn_report("a program lacking bitmap support " + "modified this file, so all bitmaps are now " + "considered inconsistent"); + } + error_printf("Some clusters may be leaked, " + "run 'qemu-img check -r' on the image " + "file to fix."); + if (need_update_header != NULL) { + /* Updating is needed to drop invalid bitmap extension. */ + *need_update_header = true; + } + break; + } + + ret = bdrv_pread(bs->file, offset, &bitmaps_ext, ext.len); + if (ret < 0) { + error_setg_errno(errp, -ret, "bitmaps_ext: " + "Could not read ext header"); + return ret; + } + + if (bitmaps_ext.reserved32 != 0) { + error_setg_errno(errp, -ret, "bitmaps_ext: " + "Reserved field is not zero"); + return -EINVAL; + } + + bitmaps_ext.nb_bitmaps = be32_to_cpu(bitmaps_ext.nb_bitmaps); + bitmaps_ext.bitmap_directory_size = + be64_to_cpu(bitmaps_ext.bitmap_directory_size); + bitmaps_ext.bitmap_directory_offset = + be64_to_cpu(bitmaps_ext.bitmap_directory_offset); + + if (bitmaps_ext.nb_bitmaps > QCOW2_MAX_BITMAPS) { + error_setg(errp, + "bitmaps_ext: Image has %" PRIu32 " bitmaps, " + "exceeding the QEMU supported maximum of %d", + bitmaps_ext.nb_bitmaps, QCOW2_MAX_BITMAPS); + return -EINVAL; + } + + if (bitmaps_ext.nb_bitmaps == 0) { + error_setg(errp, "found bitmaps extension with zero bitmaps"); + return -EINVAL; + } + + if (offset_into_cluster(s, bitmaps_ext.bitmap_directory_offset)) { + error_setg(errp, "bitmaps_ext: " + "invalid bitmap directory offset"); + return -EINVAL; + } + + if (bitmaps_ext.bitmap_directory_size > + QCOW2_MAX_BITMAP_DIRECTORY_SIZE) { + error_setg(errp, "bitmaps_ext: " + "bitmap directory size (%" PRIu64 ") exceeds " + "the maximum supported size (%d)", + bitmaps_ext.bitmap_directory_size, + QCOW2_MAX_BITMAP_DIRECTORY_SIZE); + return -EINVAL; + } + + s->nb_bitmaps = bitmaps_ext.nb_bitmaps; + s->bitmap_directory_offset = + bitmaps_ext.bitmap_directory_offset; + s->bitmap_directory_size = + bitmaps_ext.bitmap_directory_size; + +#ifdef DEBUG_EXT + printf("Qcow2: Got bitmaps extension: " + "offset=%" PRIu64 " nb_bitmaps=%" PRIu32 "\n", + s->bitmap_directory_offset, s->nb_bitmaps); +#endif + break; + + case QCOW2_EXT_MAGIC_DATA_FILE: + { + s->image_data_file = g_malloc0(ext.len + 1); + ret = bdrv_pread(bs->file, offset, s->image_data_file, ext.len); + if (ret < 0) { + error_setg_errno(errp, -ret, + "ERROR: Could not read data file name"); + return ret; + } +#ifdef DEBUG_EXT + printf("Qcow2: Got external data file %s\n", s->image_data_file); +#endif + break; + } + + default: + /* unknown magic - save it in case we need to rewrite the header */ + /* If you add a new feature, make sure to also update the fast + * path of qcow2_make_empty() to deal with it. */ + { + 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) +{ + g_autoptr(GString) features = g_string_sized_new(60); + + while (table && table->name[0] != '\0') { + if (table->type == QCOW2_FEAT_TYPE_INCOMPATIBLE) { + if (mask & (1ULL << table->bit)) { + if (features->len > 0) { + g_string_append(features, ", "); + } + g_string_append_printf(features, "%.46s", table->name); + mask &= ~(1ULL << table->bit); + } + } + table++; + } + + if (mask) { + if (features->len > 0) { + g_string_append(features, ", "); + } + g_string_append_printf(features, + "Unknown incompatible feature: %" PRIx64, mask); + } + + error_setg(errp, "Unsupported qcow2 feature(s): %s", features->str); +} + +/* + * 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 = qcow2_flush_caches(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 = qcow2_flush_caches(bs); + if (ret < 0) { + return ret; + } + + s->incompatible_features &= ~QCOW2_INCOMPAT_CORRUPT; + return qcow2_update_header(bs); + } + return 0; +} + +static void qcow2_add_check_result(BdrvCheckResult *out, + const BdrvCheckResult *src, + bool set_allocation_info) +{ + out->corruptions += src->corruptions; + out->leaks += src->leaks; + out->check_errors += src->check_errors; + out->corruptions_fixed += src->corruptions_fixed; + out->leaks_fixed += src->leaks_fixed; + + if (set_allocation_info) { + out->image_end_offset = src->image_end_offset; + out->bfi = src->bfi; + } +} + +static int coroutine_fn qcow2_co_check_locked(BlockDriverState *bs, + BdrvCheckResult *result, + BdrvCheckMode fix) +{ + BdrvCheckResult snapshot_res = {}; + BdrvCheckResult refcount_res = {}; + int ret; + + memset(result, 0, sizeof(*result)); + + ret = qcow2_check_read_snapshot_table(bs, &snapshot_res, fix); + if (ret < 0) { + qcow2_add_check_result(result, &snapshot_res, false); + return ret; + } + + ret = qcow2_check_refcounts(bs, &refcount_res, fix); + qcow2_add_check_result(result, &refcount_res, true); + if (ret < 0) { + qcow2_add_check_result(result, &snapshot_res, false); + return ret; + } + + ret = qcow2_check_fix_snapshot_table(bs, &snapshot_res, fix); + qcow2_add_check_result(result, &snapshot_res, false); + 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 coroutine_fn qcow2_co_check(BlockDriverState *bs, + BdrvCheckResult *result, + BdrvCheckMode fix) +{ + BDRVQcow2State *s = bs->opaque; + int ret; + + qemu_co_mutex_lock(&s->lock); + ret = qcow2_co_check_locked(bs, result, fix); + qemu_co_mutex_unlock(&s->lock); + return ret; +} + +int qcow2_validate_table(BlockDriverState *bs, uint64_t offset, + uint64_t entries, size_t entry_len, + int64_t max_size_bytes, const char *table_name, + Error **errp) +{ + BDRVQcow2State *s = bs->opaque; + + if (entries > max_size_bytes / entry_len) { + error_setg(errp, "%s too large", table_name); + return -EFBIG; + } + + /* 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 ((INT64_MAX - entries * entry_len < offset) || + (offset_into_cluster(s, offset) != 0)) { + error_setg(errp, "%s offset invalid", table_name); + return -EINVAL; + } + + return 0; +} + +static const char *const mutable_opts[] = { + QCOW2_OPT_LAZY_REFCOUNTS, + QCOW2_OPT_DISCARD_REQUEST, + QCOW2_OPT_DISCARD_SNAPSHOT, + QCOW2_OPT_DISCARD_OTHER, + QCOW2_OPT_OVERLAP, + QCOW2_OPT_OVERLAP_TEMPLATE, + QCOW2_OPT_OVERLAP_MAIN_HEADER, + QCOW2_OPT_OVERLAP_ACTIVE_L1, + QCOW2_OPT_OVERLAP_ACTIVE_L2, + QCOW2_OPT_OVERLAP_REFCOUNT_TABLE, + QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK, + QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE, + QCOW2_OPT_OVERLAP_INACTIVE_L1, + QCOW2_OPT_OVERLAP_INACTIVE_L2, + QCOW2_OPT_OVERLAP_BITMAP_DIRECTORY, + QCOW2_OPT_CACHE_SIZE, + QCOW2_OPT_L2_CACHE_SIZE, + QCOW2_OPT_L2_CACHE_ENTRY_SIZE, + QCOW2_OPT_REFCOUNT_CACHE_SIZE, + QCOW2_OPT_CACHE_CLEAN_INTERVAL, + NULL +}; + +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_OVERLAP_BITMAP_DIRECTORY, + .type = QEMU_OPT_BOOL, + .help = "Check for unintended writes into the bitmap directory", + }, + { + .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_L2_CACHE_ENTRY_SIZE, + .type = QEMU_OPT_SIZE, + .help = "Size of each entry in the L2 cache", + }, + { + .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, + [QCOW2_OL_BITMAP_DIRECTORY_BITNR] = QCOW2_OPT_OVERLAP_BITMAP_DIRECTORY, +}; + +static void cache_clean_timer_cb(void *opaque) +{ + BlockDriverState *bs = opaque; + BDRVQcow2State *s = bs->opaque; + qcow2_cache_clean_unused(s->l2_table_cache); + qcow2_cache_clean_unused(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_with_attrs(context, QEMU_CLOCK_VIRTUAL, + SCALE_MS, QEMU_TIMER_ATTR_EXTERNAL, + 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_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 bool read_cache_sizes(BlockDriverState *bs, QemuOpts *opts, + uint64_t *l2_cache_size, + uint64_t *l2_cache_entry_size, + uint64_t *refcount_cache_size, Error **errp) +{ + BDRVQcow2State *s = bs->opaque; + uint64_t combined_cache_size, l2_cache_max_setting; + bool l2_cache_size_set, refcount_cache_size_set, combined_cache_size_set; + bool l2_cache_entry_size_set; + int min_refcount_cache = MIN_REFCOUNT_CACHE_SIZE * s->cluster_size; + uint64_t virtual_disk_size = bs->total_sectors * BDRV_SECTOR_SIZE; + uint64_t max_l2_entries = DIV_ROUND_UP(virtual_disk_size, s->cluster_size); + /* An L2 table is always one cluster in size so the max cache size + * should be a multiple of the cluster size. */ + uint64_t max_l2_cache = ROUND_UP(max_l2_entries * l2_entry_size(s), + s->cluster_size); + + 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); + l2_cache_entry_size_set = qemu_opt_get(opts, QCOW2_OPT_L2_CACHE_ENTRY_SIZE); + + combined_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_CACHE_SIZE, 0); + l2_cache_max_setting = qemu_opt_get_size(opts, QCOW2_OPT_L2_CACHE_SIZE, + DEFAULT_L2_CACHE_MAX_SIZE); + *refcount_cache_size = qemu_opt_get_size(opts, + QCOW2_OPT_REFCOUNT_CACHE_SIZE, 0); + + *l2_cache_entry_size = qemu_opt_get_size( + opts, QCOW2_OPT_L2_CACHE_ENTRY_SIZE, s->cluster_size); + + *l2_cache_size = MIN(max_l2_cache, l2_cache_max_setting); + + 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 " + "at the same time"); + return false; + } else if (l2_cache_size_set && + (l2_cache_max_setting > combined_cache_size)) { + error_setg(errp, QCOW2_OPT_L2_CACHE_SIZE " may not exceed " + QCOW2_OPT_CACHE_SIZE); + return false; + } else if (*refcount_cache_size > combined_cache_size) { + error_setg(errp, QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not exceed " + QCOW2_OPT_CACHE_SIZE); + return false; + } + + 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 { + /* Assign as much memory as possible to the L2 cache, and + * use the remainder for the refcount cache */ + if (combined_cache_size >= max_l2_cache + min_refcount_cache) { + *l2_cache_size = max_l2_cache; + *refcount_cache_size = combined_cache_size - *l2_cache_size; + } else { + *refcount_cache_size = + MIN(combined_cache_size, min_refcount_cache); + *l2_cache_size = combined_cache_size - *refcount_cache_size; + } + } + } + + /* + * If the L2 cache is not enough to cover the whole disk then + * default to 4KB entries. Smaller entries reduce the cost of + * loads and evictions and increase I/O performance. + */ + if (*l2_cache_size < max_l2_cache && !l2_cache_entry_size_set) { + *l2_cache_entry_size = MIN(s->cluster_size, 4096); + } + + /* l2_cache_size and refcount_cache_size are ensured to have at least + * their minimum values in qcow2_update_options_prepare() */ + + if (*l2_cache_entry_size < (1 << MIN_CLUSTER_BITS) || + *l2_cache_entry_size > s->cluster_size || + !is_power_of_2(*l2_cache_entry_size)) { + error_setg(errp, "L2 cache entry size must be a power of two " + "between %d and the cluster size (%d)", + 1 << MIN_CLUSTER_BITS, s->cluster_size); + return false; + } + + return true; +} + +typedef struct Qcow2ReopenState { + Qcow2Cache *l2_table_cache; + Qcow2Cache *refcount_block_cache; + int l2_slice_size; /* Number of entries in a slice of the L2 table */ + 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, l2_cache_entry_size, refcount_cache_size; + int i; + const char *encryptfmt; + QDict *encryptopts = 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); + if (!qemu_opts_absorb_qdict(opts, options, errp)) { + ret = -EINVAL; + goto fail; + } + + /* get L2 table/refcount block cache size from command line options */ + if (!read_cache_sizes(bs, opts, &l2_cache_size, &l2_cache_entry_size, + &refcount_cache_size, errp)) { + ret = -EINVAL; + goto fail; + } + + l2_cache_size /= l2_cache_entry_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_slice_size = l2_cache_entry_size / l2_entry_size(s); + r->l2_table_cache = qcow2_cache_create(bs, l2_cache_size, + l2_cache_entry_size); + r->refcount_block_cache = qcow2_cache_create(bs, refcount_cache_size, + s->cluster_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, + DEFAULT_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_put_str(encryptopts, "format", "qcow"); + r->crypto_opts = block_crypto_open_opts_init(encryptopts, errp); + if (!r->crypto_opts) { + ret = -EINVAL; + goto fail; + } + 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_put_str(encryptopts, "format", "luks"); + r->crypto_opts = block_crypto_open_opts_init(encryptopts, errp); + if (!r->crypto_opts) { + ret = -EINVAL; + goto fail; + } + break; + + default: + error_setg(errp, "Unsupported encryption method %d", + s->crypt_method_header); + ret = -EINVAL; + goto fail; + } + + ret = 0; +fail: + qobject_unref(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(s->l2_table_cache); + } + if (s->refcount_block_cache) { + qcow2_cache_destroy(s->refcount_block_cache); + } + s->l2_table_cache = r->l2_table_cache; + s->refcount_block_cache = r->refcount_block_cache; + s->l2_slice_size = r->l2_slice_size; + + 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(r->l2_table_cache); + } + if (r->refcount_block_cache) { + qcow2_cache_destroy(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 validate_compression_type(BDRVQcow2State *s, Error **errp) +{ + switch (s->compression_type) { + case QCOW2_COMPRESSION_TYPE_ZLIB: +#ifdef CONFIG_ZSTD + case QCOW2_COMPRESSION_TYPE_ZSTD: +#endif + break; + + default: + error_setg(errp, "qcow2: unknown compression type: %u", + s->compression_type); + return -ENOTSUP; + } + + /* + * if the compression type differs from QCOW2_COMPRESSION_TYPE_ZLIB + * the incompatible feature flag must be set + */ + if (s->compression_type == QCOW2_COMPRESSION_TYPE_ZLIB) { + if (s->incompatible_features & QCOW2_INCOMPAT_COMPRESSION) { + error_setg(errp, "qcow2: Compression type incompatible feature " + "bit must not be set"); + return -EINVAL; + } + } else { + if (!(s->incompatible_features & QCOW2_INCOMPAT_COMPRESSION)) { + error_setg(errp, "qcow2: Compression type incompatible feature " + "bit must be set"); + return -EINVAL; + } + } + + return 0; +} + +/* Called with s->lock held. */ +static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options, + int flags, Error **errp) +{ + ERRP_GUARD(); + BDRVQcow2State *s = bs->opaque; + unsigned int len, i; + int ret = 0; + QCowHeader header; + uint64_t ext_end; + uint64_t l1_vm_state_index; + bool update_header = false; + + ret = bdrv_pread(bs->file, 0, &header, sizeof(header)); + if (ret < 0) { + error_setg_errno(errp, -ret, "Could not read qcow2 header"); + goto fail; + } + header.magic = be32_to_cpu(header.magic); + header.version = be32_to_cpu(header.version); + header.backing_file_offset = be64_to_cpu(header.backing_file_offset); + header.backing_file_size = be32_to_cpu(header.backing_file_size); + header.size = be64_to_cpu(header.size); + header.cluster_bits = be32_to_cpu(header.cluster_bits); + header.crypt_method = be32_to_cpu(header.crypt_method); + header.l1_table_offset = be64_to_cpu(header.l1_table_offset); + header.l1_size = be32_to_cpu(header.l1_size); + header.refcount_table_offset = be64_to_cpu(header.refcount_table_offset); + header.refcount_table_clusters = + be32_to_cpu(header.refcount_table_clusters); + header.snapshots_offset = be64_to_cpu(header.snapshots_offset); + header.nb_snapshots = be32_to_cpu(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; + + /* 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 { + header.incompatible_features = + be64_to_cpu(header.incompatible_features); + header.compatible_features = be64_to_cpu(header.compatible_features); + header.autoclear_features = be64_to_cpu(header.autoclear_features); + header.refcount_order = be32_to_cpu(header.refcount_order); + header.header_length = be32_to_cpu(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; + + /* + * Handle compression type + * Older qcow2 images don't contain the compression type header. + * Distinguish them by the header length and use + * the only valid (default) compression type in that case + */ + if (header.header_length > offsetof(QCowHeader, compression_type)) { + s->compression_type = header.compression_type; + } else { + s->compression_type = QCOW2_COMPRESSION_TYPE_ZLIB; + } + + ret = validate_compression_type(s, errp); + if (ret) { + goto fail; + } + + if (s->incompatible_features & ~QCOW2_INCOMPAT_MASK) { + void *feature_table = NULL; + qcow2_read_extensions(bs, header.header_length, ext_end, + &feature_table, flags, NULL, 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; + } + } + + s->subclusters_per_cluster = + has_subclusters(s) ? QCOW_EXTL2_SUBCLUSTERS_PER_CLUSTER : 1; + s->subcluster_size = s->cluster_size / s->subclusters_per_cluster; + s->subcluster_bits = ctz32(s->subcluster_size); + + if (s->subcluster_size < (1 << MIN_CLUSTER_BITS)) { + error_setg(errp, "Unsupported subcluster size: %d", s->subcluster_size); + ret = -EINVAL; + 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 - ctz32(l2_entry_size(s)); + 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 / BDRV_SECTOR_SIZE; + 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 == 0 && !(flags & BDRV_O_CHECK)) { + error_setg(errp, "Image does not contain a reference count table"); + ret = -EINVAL; + goto fail; + } + + ret = qcow2_validate_table(bs, s->refcount_table_offset, + header.refcount_table_clusters, + s->cluster_size, QCOW_MAX_REFTABLE_SIZE, + "Reference count table", errp); + if (ret < 0) { + goto fail; + } + + if (!(flags & BDRV_O_CHECK)) { + /* + * The total size in bytes of the snapshot table is checked in + * qcow2_read_snapshots() because the size of each snapshot is + * variable and we don't know it yet. + * Here we only check the offset and number of snapshots. + */ + ret = qcow2_validate_table(bs, header.snapshots_offset, + header.nb_snapshots, + sizeof(QCowSnapshotHeader), + sizeof(QCowSnapshotHeader) * + QCOW_MAX_SNAPSHOTS, + "Snapshot table", errp); + if (ret < 0) { + goto fail; + } + } + + /* read the level 1 table */ + ret = qcow2_validate_table(bs, header.l1_table_offset, + header.l1_size, L1E_SIZE, + QCOW_MAX_L1_SIZE, "Active L1 table", errp); + if (ret < 0) { + goto fail; + } + s->l1_size = header.l1_size; + s->l1_table_offset = header.l1_table_offset; + + 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; + } + + if (s->l1_size > 0) { + s->l1_table = qemu_try_blockalign(bs->file->bs, s->l1_size * L1E_SIZE); + 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 * L1E_SIZE); + if (ret < 0) { + error_setg_errno(errp, -ret, "Could not read L1 table"); + goto fail; + } + for(i = 0;i < s->l1_size; i++) { + s->l1_table[i] = be64_to_cpu(s->l1_table[i]); + } + } + + /* Parse driver-specific options */ + ret = qcow2_update_options(bs, options, flags, errp); + if (ret < 0) { + goto fail; + } + + 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, &update_header, errp)) { + ret = -EINVAL; + goto fail; + } + + /* Open external data file */ + s->data_file = bdrv_open_child(NULL, options, "data-file", bs, + &child_of_bds, BDRV_CHILD_DATA, + true, errp); + if (*errp) { + ret = -EINVAL; + goto fail; + } + + if (s->incompatible_features & QCOW2_INCOMPAT_DATA_FILE) { + if (!s->data_file && s->image_data_file) { + s->data_file = bdrv_open_child(s->image_data_file, options, + "data-file", bs, &child_of_bds, + BDRV_CHILD_DATA, false, errp); + if (!s->data_file) { + ret = -EINVAL; + goto fail; + } + } + if (!s->data_file) { + error_setg(errp, "'data-file' is required for this image"); + ret = -EINVAL; + goto fail; + } + + /* No data here */ + bs->file->role &= ~BDRV_CHILD_DATA; + + /* Must succeed because we have given up permissions if anything */ + bdrv_child_refresh_perms(bs, bs->file, &error_abort); + } else { + if (s->data_file) { + error_setg(errp, "'data-file' can only be set for images with an " + "external data file"); + ret = -EINVAL; + goto fail; + } + + s->data_file = bs->file; + + if (data_file_is_raw(bs)) { + error_setg(errp, "data-file-raw requires a data file"); + 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, "encrypt.", + NULL, NULL, cflags, + QCOW2_MAX_THREADS, 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->auto_backing_file, len); + if (ret < 0) { + error_setg_errno(errp, -ret, "Could not read backing file name"); + goto fail; + } + bs->auto_backing_file[len] = '\0'; + pstrcpy(bs->backing_file, sizeof(bs->backing_file), + bs->auto_backing_file); + s->image_backing_file = g_strdup(bs->auto_backing_file); + } + + /* + * Internal snapshots; skip reading them in check mode, because + * we do not need them then, and we do not want to abort because + * of a broken table. + */ + if (!(flags & BDRV_O_CHECK)) { + s->snapshots_offset = header.snapshots_offset; + s->nb_snapshots = header.nb_snapshots; + + ret = qcow2_read_snapshots(bs, errp); + if (ret < 0) { + goto fail; + } + } + + /* Clear unknown autoclear feature bits */ + update_header |= s->autoclear_features & ~QCOW2_AUTOCLEAR_MASK; + update_header = update_header && bdrv_is_writable(bs); + if (update_header) { + s->autoclear_features &= QCOW2_AUTOCLEAR_MASK; + } + + /* == Handle persistent dirty bitmaps == + * + * We want load dirty bitmaps in three cases: + * + * 1. Normal open of the disk in active mode, not related to invalidation + * after migration. + * + * 2. Invalidation of the target vm after pre-copy phase of migration, if + * bitmaps are _not_ migrating through migration channel, i.e. + * 'dirty-bitmaps' capability is disabled. + * + * 3. Invalidation of source vm after failed or canceled migration. + * This is a very interesting case. There are two possible types of + * bitmaps: + * + * A. Stored on inactivation and removed. They should be loaded from the + * image. + * + * B. Not stored: not-persistent bitmaps and bitmaps, migrated through + * the migration channel (with dirty-bitmaps capability). + * + * On the other hand, there are two possible sub-cases: + * + * 3.1 disk was changed by somebody else while were inactive. In this + * case all in-RAM dirty bitmaps (both persistent and not) are + * definitely invalid. And we don't have any method to determine + * this. + * + * Simple and safe thing is to just drop all the bitmaps of type B on + * inactivation. But in this case we lose bitmaps in valid 4.2 case. + * + * On the other hand, resuming source vm, if disk was already changed + * is a bad thing anyway: not only bitmaps, the whole vm state is + * out of sync with disk. + * + * This means, that user or management tool, who for some reason + * decided to resume source vm, after disk was already changed by + * target vm, should at least drop all dirty bitmaps by hand. + * + * So, we can ignore this case for now, but TODO: "generation" + * extension for qcow2, to determine, that image was changed after + * last inactivation. And if it is changed, we will drop (or at least + * mark as 'invalid' all the bitmaps of type B, both persistent + * and not). + * + * 3.2 disk was _not_ changed while were inactive. Bitmaps may be saved + * to disk ('dirty-bitmaps' capability disabled), or not saved + * ('dirty-bitmaps' capability enabled), but we don't need to care + * of: let's load bitmaps as always: stored bitmaps will be loaded, + * and not stored has flag IN_USE=1 in the image and will be skipped + * on loading. + * + * One remaining possible case when we don't want load bitmaps: + * + * 4. Open disk in inactive mode in target vm (bitmaps are migrating or + * will be loaded on invalidation, no needs try loading them before) + */ + + if (!(bdrv_get_flags(bs) & BDRV_O_INACTIVE)) { + /* It's case 1, 2 or 3.2. Or 3.1 which is BUG in management layer. */ + bool header_updated; + if (!qcow2_load_dirty_bitmaps(bs, &header_updated, errp)) { + ret = -EINVAL; + goto fail; + } + + update_header = update_header && !header_updated; + } + + if (update_header) { + ret = qcow2_update_header(bs); + if (ret < 0) { + error_setg_errno(errp, -ret, "Could not update qcow2 header"); + goto fail; + } + } + + bs->supported_zero_flags = header.version >= 3 ? + BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK : 0; + bs->supported_truncate_flags = BDRV_REQ_ZERO_WRITE; + + /* Repair image if dirty */ + if (!(flags & BDRV_O_CHECK) && bdrv_is_writable(bs) && + (s->incompatible_features & QCOW2_INCOMPAT_DIRTY)) { + BdrvCheckResult result = {0}; + + ret = qcow2_co_check_locked(bs, &result, + BDRV_FIX_ERRORS | BDRV_FIX_LEAKS); + if (ret < 0 || result.check_errors) { + if (ret >= 0) { + ret = -EIO; + } + 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 + + qemu_co_queue_init(&s->thread_task_queue); + + return ret; + + fail: + g_free(s->image_data_file); + if (has_data_file(bs)) { + bdrv_unref_child(bs, s->data_file); + s->data_file = NULL; + } + 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(s->l2_table_cache); + } + if (s->refcount_block_cache) { + qcow2_cache_destroy(s->refcount_block_cache); + } + qcrypto_block_free(s->crypto); + qapi_free_QCryptoBlockOpenOptions(s->crypto_opts); + return ret; +} + +typedef struct QCow2OpenCo { + BlockDriverState *bs; + QDict *options; + int flags; + Error **errp; + int ret; +} QCow2OpenCo; + +static void coroutine_fn qcow2_open_entry(void *opaque) +{ + QCow2OpenCo *qoc = opaque; + BDRVQcow2State *s = qoc->bs->opaque; + + qemu_co_mutex_lock(&s->lock); + qoc->ret = qcow2_do_open(qoc->bs, qoc->options, qoc->flags, qoc->errp); + qemu_co_mutex_unlock(&s->lock); +} + +static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, + Error **errp) +{ + BDRVQcow2State *s = bs->opaque; + QCow2OpenCo qoc = { + .bs = bs, + .options = options, + .flags = flags, + .errp = errp, + .ret = -EINPROGRESS + }; + + bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds, + BDRV_CHILD_IMAGE, false, errp); + if (!bs->file) { + return -EINVAL; + } + + /* Initialise locks */ + qemu_co_mutex_init(&s->lock); + + if (qemu_in_coroutine()) { + /* From bdrv_co_create. */ + qcow2_open_entry(&qoc); + } else { + assert(qemu_get_current_aio_context() == qemu_get_aio_context()); + qemu_coroutine_enter(qemu_coroutine_create(qcow2_open_entry, &qoc)); + BDRV_POLL_WHILE(bs, qoc.ret == -EINPROGRESS); + } + return qoc.ret; +} + +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 = qcrypto_block_get_sector_size(s->crypto); + } + bs->bl.pwrite_zeroes_alignment = s->subcluster_size; + bs->bl.pdiscard_alignment = s->cluster_size; +} + +static int qcow2_reopen_prepare(BDRVReopenState *state, + BlockReopenQueue *queue, Error **errp) +{ + BDRVQcow2State *s = state->bs->opaque; + 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 = qcow2_reopen_bitmaps_ro(state->bs, errp); + if (ret < 0) { + goto fail; + } + + ret = bdrv_flush(state->bs); + if (ret < 0) { + goto fail; + } + + ret = qcow2_mark_clean(state->bs); + if (ret < 0) { + goto fail; + } + } + + /* + * Without an external data file, s->data_file points to the same BdrvChild + * as bs->file. It needs to be resynced after reopen because bs->file may + * be changed. We can't use it in the meantime. + */ + if (!has_data_file(state->bs)) { + assert(s->data_file == state->bs->file); + s->data_file = NULL; + } + + return 0; + +fail: + qcow2_update_options_abort(state->bs, r); + g_free(r); + return ret; +} + +static void qcow2_reopen_commit(BDRVReopenState *state) +{ + BDRVQcow2State *s = state->bs->opaque; + + qcow2_update_options_commit(state->bs, state->opaque); + if (!s->data_file) { + /* + * If we don't have an external data file, s->data_file was cleared by + * qcow2_reopen_prepare() and needs to be updated. + */ + s->data_file = state->bs->file; + } + g_free(state->opaque); +} + +static void qcow2_reopen_commit_post(BDRVReopenState *state) +{ + if (state->flags & BDRV_O_RDWR) { + Error *local_err = NULL; + + if (qcow2_reopen_bitmaps_rw(state->bs, &local_err) < 0) { + /* + * This is not fatal, bitmaps just left read-only, so all following + * writes will fail. User can remove read-only bitmaps to unblock + * writes or retry reopen. + */ + error_reportf_err(local_err, + "%s: Failed to make dirty bitmaps writable: ", + bdrv_get_node_name(state->bs)); + } + } +} + +static void qcow2_reopen_abort(BDRVReopenState *state) +{ + BDRVQcow2State *s = state->bs->opaque; + + if (!s->data_file) { + /* + * If we don't have an external data file, s->data_file was cleared by + * qcow2_reopen_prepare() and needs to be restored. + */ + s->data_file = state->bs->file; + } + 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 int coroutine_fn qcow2_co_block_status(BlockDriverState *bs, + bool want_zero, + int64_t offset, int64_t count, + int64_t *pnum, int64_t *map, + BlockDriverState **file) +{ + BDRVQcow2State *s = bs->opaque; + uint64_t host_offset; + unsigned int bytes; + QCow2SubclusterType type; + int ret, status = 0; + + qemu_co_mutex_lock(&s->lock); + + if (!s->metadata_preallocation_checked) { + ret = qcow2_detect_metadata_preallocation(bs); + s->metadata_preallocation = (ret == 1); + s->metadata_preallocation_checked = true; + } + + bytes = MIN(INT_MAX, count); + ret = qcow2_get_host_offset(bs, offset, &bytes, &host_offset, &type); + qemu_co_mutex_unlock(&s->lock); + if (ret < 0) { + return ret; + } + + *pnum = bytes; + + if ((type == QCOW2_SUBCLUSTER_NORMAL || + type == QCOW2_SUBCLUSTER_ZERO_ALLOC || + type == QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC) && !s->crypto) { + *map = host_offset; + *file = s->data_file->bs; + status |= BDRV_BLOCK_OFFSET_VALID; + } + if (type == QCOW2_SUBCLUSTER_ZERO_PLAIN || + type == QCOW2_SUBCLUSTER_ZERO_ALLOC) { + status |= BDRV_BLOCK_ZERO; + } else if (type != QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN && + type != QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC) { + status |= BDRV_BLOCK_DATA; + } + if (s->metadata_preallocation && (status & BDRV_BLOCK_DATA) && + (status & BDRV_BLOCK_OFFSET_VALID)) + { + status |= BDRV_BLOCK_RECURSE; + } + return status; +} + +static coroutine_fn int qcow2_handle_l2meta(BlockDriverState *bs, + QCowL2Meta **pl2meta, + bool link_l2) +{ + int ret = 0; + QCowL2Meta *l2meta = *pl2meta; + + while (l2meta != NULL) { + QCowL2Meta *next; + + if (link_l2) { + ret = qcow2_alloc_cluster_link_l2(bs, l2meta); + if (ret) { + goto out; + } + } else { + qcow2_alloc_cluster_abort(bs, l2meta); + } + + /* Take the request off the list of running requests */ + QLIST_REMOVE(l2meta, next_in_flight); + + qemu_co_queue_restart_all(&l2meta->dependent_requests); + + next = l2meta->next; + g_free(l2meta); + l2meta = next; + } +out: + *pl2meta = l2meta; + return ret; +} + +static coroutine_fn int +qcow2_co_preadv_encrypted(BlockDriverState *bs, + uint64_t host_offset, + uint64_t offset, + uint64_t bytes, + QEMUIOVector *qiov, + uint64_t qiov_offset) +{ + int ret; + BDRVQcow2State *s = bs->opaque; + uint8_t *buf; + + assert(bs->encrypted && s->crypto); + assert(bytes <= QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); + + /* + * For encrypted images, read everything into a temporary + * contiguous buffer on which the AES functions can work. + * Also, decryption in a separate buffer is better as it + * prevents the guest from learning information about the + * encrypted nature of the virtual disk. + */ + + buf = qemu_try_blockalign(s->data_file->bs, bytes); + if (buf == NULL) { + return -ENOMEM; + } + + BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); + ret = bdrv_co_pread(s->data_file, host_offset, bytes, buf, 0); + if (ret < 0) { + goto fail; + } + + if (qcow2_co_decrypt(bs, host_offset, offset, buf, bytes) < 0) + { + ret = -EIO; + goto fail; + } + qemu_iovec_from_buf(qiov, qiov_offset, buf, bytes); + +fail: + qemu_vfree(buf); + + return ret; +} + +typedef struct Qcow2AioTask { + AioTask task; + + BlockDriverState *bs; + QCow2SubclusterType subcluster_type; /* only for read */ + uint64_t host_offset; /* or l2_entry for compressed read */ + uint64_t offset; + uint64_t bytes; + QEMUIOVector *qiov; + uint64_t qiov_offset; + QCowL2Meta *l2meta; /* only for write */ +} Qcow2AioTask; + +static coroutine_fn int qcow2_co_preadv_task_entry(AioTask *task); +static coroutine_fn int qcow2_add_task(BlockDriverState *bs, + AioTaskPool *pool, + AioTaskFunc func, + QCow2SubclusterType subcluster_type, + uint64_t host_offset, + uint64_t offset, + uint64_t bytes, + QEMUIOVector *qiov, + size_t qiov_offset, + QCowL2Meta *l2meta) +{ + Qcow2AioTask local_task; + Qcow2AioTask *task = pool ? g_new(Qcow2AioTask, 1) : &local_task; + + *task = (Qcow2AioTask) { + .task.func = func, + .bs = bs, + .subcluster_type = subcluster_type, + .qiov = qiov, + .host_offset = host_offset, + .offset = offset, + .bytes = bytes, + .qiov_offset = qiov_offset, + .l2meta = l2meta, + }; + + trace_qcow2_add_task(qemu_coroutine_self(), bs, pool, + func == qcow2_co_preadv_task_entry ? "read" : "write", + subcluster_type, host_offset, offset, bytes, + qiov, qiov_offset); + + if (!pool) { + return func(&task->task); + } + + aio_task_pool_start_task(pool, &task->task); + + return 0; +} + +static coroutine_fn int qcow2_co_preadv_task(BlockDriverState *bs, + QCow2SubclusterType subc_type, + uint64_t host_offset, + uint64_t offset, uint64_t bytes, + QEMUIOVector *qiov, + size_t qiov_offset) +{ + BDRVQcow2State *s = bs->opaque; + + switch (subc_type) { + case QCOW2_SUBCLUSTER_ZERO_PLAIN: + case QCOW2_SUBCLUSTER_ZERO_ALLOC: + /* Both zero types are handled in qcow2_co_preadv_part */ + g_assert_not_reached(); + + case QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN: + case QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC: + assert(bs->backing); /* otherwise handled in qcow2_co_preadv_part */ + + BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO); + return bdrv_co_preadv_part(bs->backing, offset, bytes, + qiov, qiov_offset, 0); + + case QCOW2_SUBCLUSTER_COMPRESSED: + return qcow2_co_preadv_compressed(bs, host_offset, + offset, bytes, qiov, qiov_offset); + + case QCOW2_SUBCLUSTER_NORMAL: + if (bs->encrypted) { + return qcow2_co_preadv_encrypted(bs, host_offset, + offset, bytes, qiov, qiov_offset); + } + + BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); + return bdrv_co_preadv_part(s->data_file, host_offset, + bytes, qiov, qiov_offset, 0); + + default: + g_assert_not_reached(); + } + + g_assert_not_reached(); +} + +static coroutine_fn int qcow2_co_preadv_task_entry(AioTask *task) +{ + Qcow2AioTask *t = container_of(task, Qcow2AioTask, task); + + assert(!t->l2meta); + + return qcow2_co_preadv_task(t->bs, t->subcluster_type, + t->host_offset, t->offset, t->bytes, + t->qiov, t->qiov_offset); +} + +static coroutine_fn int qcow2_co_preadv_part(BlockDriverState *bs, + int64_t offset, int64_t bytes, + QEMUIOVector *qiov, + size_t qiov_offset, + BdrvRequestFlags flags) +{ + BDRVQcow2State *s = bs->opaque; + int ret = 0; + unsigned int cur_bytes; /* number of bytes in current iteration */ + uint64_t host_offset = 0; + QCow2SubclusterType type; + AioTaskPool *aio = NULL; + + while (bytes != 0 && aio_task_pool_status(aio) == 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); + } + + qemu_co_mutex_lock(&s->lock); + ret = qcow2_get_host_offset(bs, offset, &cur_bytes, + &host_offset, &type); + qemu_co_mutex_unlock(&s->lock); + if (ret < 0) { + goto out; + } + + if (type == QCOW2_SUBCLUSTER_ZERO_PLAIN || + type == QCOW2_SUBCLUSTER_ZERO_ALLOC || + (type == QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN && !bs->backing) || + (type == QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC && !bs->backing)) + { + qemu_iovec_memset(qiov, qiov_offset, 0, cur_bytes); + } else { + if (!aio && cur_bytes != bytes) { + aio = aio_task_pool_new(QCOW2_MAX_WORKERS); + } + ret = qcow2_add_task(bs, aio, qcow2_co_preadv_task_entry, type, + host_offset, offset, cur_bytes, + qiov, qiov_offset, NULL); + if (ret < 0) { + goto out; + } + } + + bytes -= cur_bytes; + offset += cur_bytes; + qiov_offset += cur_bytes; + } + +out: + if (aio) { + aio_task_pool_wait_all(aio); + if (ret == 0) { + ret = aio_task_pool_status(aio); + } + g_free(aio); + } + + 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 *qiov, size_t qiov_offset, + 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; + } + + /* If COW regions are handled already, skip this too */ + if (m->skip_cow) { + continue; + } + + /* + * The write request should start immediately after the first + * COW region. This does not always happen because the area + * touched by the request can be larger than the one defined + * by @m (a single request can span an area consisting of a + * mix of previously unallocated and allocated clusters, that + * is why @l2meta is a list). + */ + if (l2meta_cow_start(m) + m->cow_start.nb_bytes != offset) { + /* In this case the request starts before this region */ + assert(offset < l2meta_cow_start(m)); + assert(m->cow_start.nb_bytes == 0); + continue; + } + + /* The write request should end immediately before the second + * COW region (see above for why it does not always happen) */ + if (m->offset + m->cow_end.offset != offset + bytes) { + assert(offset + bytes > m->offset + m->cow_end.offset); + assert(m->cow_end.nb_bytes == 0); + continue; + } + + /* Make sure that adding both COW regions to the QEMUIOVector + * does not exceed IOV_MAX */ + if (qemu_iovec_subvec_niov(qiov, qiov_offset, bytes) > IOV_MAX - 2) { + continue; + } + + m->data_qiov = qiov; + m->data_qiov_offset = qiov_offset; + return true; + } + + return false; +} + +/* + * Return 1 if the COW regions read as zeroes, 0 if not, < 0 on error. + * Note that returning 0 does not guarantee non-zero data. + */ +static int is_zero_cow(BlockDriverState *bs, QCowL2Meta *m) +{ + /* + * This check is designed for optimization shortcut so it must be + * efficient. + * Instead of is_zero(), use bdrv_co_is_zero_fast() as it is + * faster (but not as accurate and can result in false negatives). + */ + int ret = bdrv_co_is_zero_fast(bs, m->offset + m->cow_start.offset, + m->cow_start.nb_bytes); + if (ret <= 0) { + return ret; + } + + return bdrv_co_is_zero_fast(bs, m->offset + m->cow_end.offset, + m->cow_end.nb_bytes); +} + +static int handle_alloc_space(BlockDriverState *bs, QCowL2Meta *l2meta) +{ + BDRVQcow2State *s = bs->opaque; + QCowL2Meta *m; + + if (!(s->data_file->bs->supported_zero_flags & BDRV_REQ_NO_FALLBACK)) { + return 0; + } + + if (bs->encrypted) { + return 0; + } + + for (m = l2meta; m != NULL; m = m->next) { + int ret; + uint64_t start_offset = m->alloc_offset + m->cow_start.offset; + unsigned nb_bytes = m->cow_end.offset + m->cow_end.nb_bytes - + m->cow_start.offset; + + if (!m->cow_start.nb_bytes && !m->cow_end.nb_bytes) { + continue; + } + + ret = is_zero_cow(bs, m); + if (ret < 0) { + return ret; + } else if (ret == 0) { + continue; + } + + /* + * instead of writing zero COW buffers, + * efficiently zero out the whole clusters + */ + + ret = qcow2_pre_write_overlap_check(bs, 0, start_offset, nb_bytes, + true); + if (ret < 0) { + return ret; + } + + BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC_SPACE); + ret = bdrv_co_pwrite_zeroes(s->data_file, start_offset, nb_bytes, + BDRV_REQ_NO_FALLBACK); + if (ret < 0) { + if (ret != -ENOTSUP && ret != -EAGAIN) { + return ret; + } + continue; + } + + trace_qcow2_skip_cow(qemu_coroutine_self(), m->offset, m->nb_clusters); + m->skip_cow = true; + } + return 0; +} + +/* + * qcow2_co_pwritev_task + * Called with s->lock unlocked + * l2meta - if not NULL, qcow2_co_pwritev_task() will consume it. Caller must + * not use it somehow after qcow2_co_pwritev_task() call + */ +static coroutine_fn int qcow2_co_pwritev_task(BlockDriverState *bs, + uint64_t host_offset, + uint64_t offset, uint64_t bytes, + QEMUIOVector *qiov, + uint64_t qiov_offset, + QCowL2Meta *l2meta) +{ + int ret; + BDRVQcow2State *s = bs->opaque; + void *crypt_buf = NULL; + QEMUIOVector encrypted_qiov; + + if (bs->encrypted) { + assert(s->crypto); + assert(bytes <= QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); + crypt_buf = qemu_try_blockalign(bs->file->bs, bytes); + if (crypt_buf == NULL) { + ret = -ENOMEM; + goto out_unlocked; + } + qemu_iovec_to_buf(qiov, qiov_offset, crypt_buf, bytes); + + if (qcow2_co_encrypt(bs, host_offset, offset, crypt_buf, bytes) < 0) { + ret = -EIO; + goto out_unlocked; + } + + qemu_iovec_init_buf(&encrypted_qiov, crypt_buf, bytes); + qiov = &encrypted_qiov; + qiov_offset = 0; + } + + /* Try to efficiently initialize the physical space with zeroes */ + ret = handle_alloc_space(bs, l2meta); + if (ret < 0) { + goto out_unlocked; + } + + /* + * 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, bytes, qiov, qiov_offset, l2meta)) { + BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); + trace_qcow2_writev_data(qemu_coroutine_self(), host_offset); + ret = bdrv_co_pwritev_part(s->data_file, host_offset, + bytes, qiov, qiov_offset, 0); + if (ret < 0) { + goto out_unlocked; + } + } + + qemu_co_mutex_lock(&s->lock); + + ret = qcow2_handle_l2meta(bs, &l2meta, true); + goto out_locked; + +out_unlocked: + qemu_co_mutex_lock(&s->lock); + +out_locked: + qcow2_handle_l2meta(bs, &l2meta, false); + qemu_co_mutex_unlock(&s->lock); + + qemu_vfree(crypt_buf); + + return ret; +} + +static coroutine_fn int qcow2_co_pwritev_task_entry(AioTask *task) +{ + Qcow2AioTask *t = container_of(task, Qcow2AioTask, task); + + assert(!t->subcluster_type); + + return qcow2_co_pwritev_task(t->bs, t->host_offset, + t->offset, t->bytes, t->qiov, t->qiov_offset, + t->l2meta); +} + +static coroutine_fn int qcow2_co_pwritev_part( + BlockDriverState *bs, int64_t offset, int64_t bytes, + QEMUIOVector *qiov, size_t qiov_offset, BdrvRequestFlags flags) +{ + BDRVQcow2State *s = bs->opaque; + int offset_in_cluster; + int ret; + unsigned int cur_bytes; /* number of sectors in current iteration */ + uint64_t host_offset; + QCowL2Meta *l2meta = NULL; + AioTaskPool *aio = NULL; + + trace_qcow2_writev_start_req(qemu_coroutine_self(), offset, bytes); + + while (bytes != 0 && aio_task_pool_status(aio) == 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); + } + + qemu_co_mutex_lock(&s->lock); + + ret = qcow2_alloc_host_offset(bs, offset, &cur_bytes, + &host_offset, &l2meta); + if (ret < 0) { + goto out_locked; + } + + ret = qcow2_pre_write_overlap_check(bs, 0, host_offset, + cur_bytes, true); + if (ret < 0) { + goto out_locked; + } + + qemu_co_mutex_unlock(&s->lock); + + if (!aio && cur_bytes != bytes) { + aio = aio_task_pool_new(QCOW2_MAX_WORKERS); + } + ret = qcow2_add_task(bs, aio, qcow2_co_pwritev_task_entry, 0, + host_offset, offset, + cur_bytes, qiov, qiov_offset, l2meta); + l2meta = NULL; /* l2meta is consumed by qcow2_co_pwritev_task() */ + if (ret < 0) { + goto fail_nometa; + } + + bytes -= cur_bytes; + offset += cur_bytes; + qiov_offset += cur_bytes; + trace_qcow2_writev_done_part(qemu_coroutine_self(), cur_bytes); + } + ret = 0; + + qemu_co_mutex_lock(&s->lock); + +out_locked: + qcow2_handle_l2meta(bs, &l2meta, false); + + qemu_co_mutex_unlock(&s->lock); + +fail_nometa: + if (aio) { + aio_task_pool_wait_all(aio); + if (ret == 0) { + ret = aio_task_pool_status(aio); + } + g_free(aio); + } + + 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; + Error *local_err = NULL; + + qcow2_store_persistent_dirty_bitmaps(bs, true, &local_err); + if (local_err != NULL) { + result = -EINVAL; + error_reportf_err(local_err, "Lost persistent bitmaps during " + "inactivation of node '%s': ", + bdrv_get_device_or_node_name(bs)); + } + + 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(s->l2_table_cache); + qcow2_cache_destroy(s->refcount_block_cache); + + qcrypto_block_free(s->crypto); + s->crypto = NULL; + qapi_free_QCryptoBlockOpenOptions(s->crypto_opts); + + g_free(s->unknown_header_fields); + cleanup_unknown_header_ext(bs); + + g_free(s->image_data_file); + g_free(s->image_backing_file); + g_free(s->image_backing_format); + + if (has_data_file(bs)) { + bdrv_unref_child(bs, s->data_file); + s->data_file = NULL; + } + + qcow2_refcount_close(bs); + qcow2_free_snapshots(bs); +} + +static void coroutine_fn qcow2_co_invalidate_cache(BlockDriverState *bs, + Error **errp) +{ + ERRP_GUARD(); + BDRVQcow2State *s = bs->opaque; + int flags = s->flags; + QCryptoBlock *crypto = NULL; + QDict *options; + 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; + qemu_co_mutex_lock(&s->lock); + ret = qcow2_do_open(bs, options, flags, errp); + qemu_co_mutex_unlock(&s->lock); + qobject_unref(options); + if (ret < 0) { + error_prepend(errp, "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); + + ret = validate_compression_type(s, NULL); + if (ret) { + goto fail; + } + + *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), + .compression_type = s->compression_type, + }; + + /* 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; + } + + /* External data file header extension */ + if (has_data_file(bs) && s->image_data_file) { + ret = header_ext_add(buf, QCOW2_EXT_MAGIC_DATA_FILE, + s->image_data_file, strlen(s->image_data_file), + buflen); + if (ret < 0) { + goto fail; + } + + buf += ret; + buflen -= ret; + } + + /* Full disk encryption header pointer extension */ + if (s->crypto_header.offset != 0) { + s->crypto_header.offset = cpu_to_be64(s->crypto_header.offset); + s->crypto_header.length = cpu_to_be64(s->crypto_header.length); + ret = header_ext_add(buf, QCOW2_EXT_MAGIC_CRYPTO_HEADER, + &s->crypto_header, sizeof(s->crypto_header), + buflen); + s->crypto_header.offset = be64_to_cpu(s->crypto_header.offset); + s->crypto_header.length = be64_to_cpu(s->crypto_header.length); + if (ret < 0) { + goto fail; + } + buf += ret; + buflen -= ret; + } + + /* + * Feature table. A mere 8 feature names occupies 392 bytes, and + * when coupled with the v3 minimum header of 104 bytes plus the + * 8-byte end-of-extension marker, that would leave only 8 bytes + * for a backing file name in an image with 512-byte clusters. + * Thus, we choose to omit this header for cluster sizes 4k and + * smaller. + */ + if (s->qcow_version >= 3 && s->cluster_size > 4096) { + static const 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_INCOMPATIBLE, + .bit = QCOW2_INCOMPAT_DATA_FILE_BITNR, + .name = "external data file", + }, + { + .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, + .bit = QCOW2_INCOMPAT_COMPRESSION_BITNR, + .name = "compression type", + }, + { + .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, + .bit = QCOW2_INCOMPAT_EXTL2_BITNR, + .name = "extended L2 entries", + }, + { + .type = QCOW2_FEAT_TYPE_COMPATIBLE, + .bit = QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR, + .name = "lazy refcounts", + }, + { + .type = QCOW2_FEAT_TYPE_AUTOCLEAR, + .bit = QCOW2_AUTOCLEAR_BITMAPS_BITNR, + .name = "bitmaps", + }, + { + .type = QCOW2_FEAT_TYPE_AUTOCLEAR, + .bit = QCOW2_AUTOCLEAR_DATA_FILE_RAW_BITNR, + .name = "raw external data", + }, + }; + + ret = header_ext_add(buf, QCOW2_EXT_MAGIC_FEATURE_TABLE, + features, sizeof(features), buflen); + if (ret < 0) { + goto fail; + } + buf += ret; + buflen -= ret; + } + + /* Bitmap extension */ + if (s->nb_bitmaps > 0) { + Qcow2BitmapHeaderExt bitmaps_header = { + .nb_bitmaps = cpu_to_be32(s->nb_bitmaps), + .bitmap_directory_size = + cpu_to_be64(s->bitmap_directory_size), + .bitmap_directory_offset = + cpu_to_be64(s->bitmap_directory_offset) + }; + ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BITMAPS, + &bitmaps_header, sizeof(bitmaps_header), + 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; + + /* Adding a backing file means that the external data file alone won't be + * enough to make sense of the content */ + if (backing_file && data_file_is_raw(bs)) { + return -EINVAL; + } + + if (backing_file && strlen(backing_file) > 1023) { + return -EINVAL; + } + + pstrcpy(bs->auto_backing_file, sizeof(bs->auto_backing_file), + backing_file ?: ""); + 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_set_up_encryption(BlockDriverState *bs, + QCryptoBlockCreateOptions *cryptoopts, + Error **errp) +{ + BDRVQcow2State *s = bs->opaque; + QCryptoBlock *crypto = NULL; + int fmt, ret; + + switch (cryptoopts->format) { + case Q_CRYPTO_BLOCK_FORMAT_LUKS: + fmt = QCOW_CRYPT_LUKS; + break; + case Q_CRYPTO_BLOCK_FORMAT_QCOW: + fmt = QCOW_CRYPT_AES; + break; + default: + error_setg(errp, "Crypto format not supported in qcow2"); + return -EINVAL; + } + + s->crypt_method_header = fmt; + + crypto = qcrypto_block_create(cryptoopts, "encrypt.", + qcow2_crypto_hdr_init_func, + qcow2_crypto_hdr_write_func, + bs, errp); + if (!crypto) { + return -EINVAL; + } + + ret = qcow2_update_header(bs); + if (ret < 0) { + error_setg_errno(errp, -ret, "Could not write encryption header"); + goto out; + } + + ret = 0; + out: + qcrypto_block_free(crypto); + return ret; +} + +/** + * Preallocates metadata structures for data clusters between @offset (in the + * guest disk) and @new_length (which is thus generally the new guest disk + * size). + * + * Returns: 0 on success, -errno on failure. + */ +static int coroutine_fn preallocate_co(BlockDriverState *bs, uint64_t offset, + uint64_t new_length, PreallocMode mode, + Error **errp) +{ + BDRVQcow2State *s = bs->opaque; + uint64_t bytes; + uint64_t host_offset = 0; + int64_t file_length; + unsigned int cur_bytes; + int ret; + QCowL2Meta *meta = NULL, *m; + + assert(offset <= new_length); + bytes = new_length - offset; + + while (bytes) { + cur_bytes = MIN(bytes, QEMU_ALIGN_DOWN(INT_MAX, s->cluster_size)); + ret = qcow2_alloc_host_offset(bs, offset, &cur_bytes, + &host_offset, &meta); + if (ret < 0) { + error_setg_errno(errp, -ret, "Allocating clusters failed"); + goto out; + } + + for (m = meta; m != NULL; m = m->next) { + m->prealloc = true; + } + + ret = qcow2_handle_l2meta(bs, &meta, true); + if (ret < 0) { + error_setg_errno(errp, -ret, "Mapping clusters failed"); + goto out; + } + + /* 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. + */ + file_length = bdrv_getlength(s->data_file->bs); + if (file_length < 0) { + error_setg_errno(errp, -file_length, "Could not get file size"); + ret = file_length; + goto out; + } + + if (host_offset + cur_bytes > file_length) { + if (mode == PREALLOC_MODE_METADATA) { + mode = PREALLOC_MODE_OFF; + } + ret = bdrv_co_truncate(s->data_file, host_offset + cur_bytes, false, + mode, 0, errp); + if (ret < 0) { + goto out; + } + } + + ret = 0; + +out: + qcow2_handle_l2meta(bs, &meta, false); + return ret; +} + +/* qcow2_refcount_metadata_size: + * @clusters: number of clusters to refcount (including data and L1/L2 tables) + * @cluster_size: size of a cluster, in bytes + * @refcount_order: refcount bits power-of-2 exponent + * @generous_increase: allow for the refcount table to be 1.5x as large as it + * needs to be + * + * Returns: Number of bytes required for refcount blocks and table metadata. + */ +int64_t qcow2_refcount_metadata_size(int64_t clusters, size_t cluster_size, + int refcount_order, bool generous_increase, + uint64_t *refblock_count) +{ + /* + * Every host cluster is reference-counted, including metadata (even + * refcount metadata is recursively included). + * + * An accurate formula for the size of refcount metadata size is difficult + * to derive. An easier method of calculation is finding the fixed point + * where no further refcount blocks or table clusters are required to + * reference count every cluster. + */ + int64_t blocks_per_table_cluster = cluster_size / REFTABLE_ENTRY_SIZE; + int64_t refcounts_per_block = cluster_size * 8 / (1 << refcount_order); + int64_t table = 0; /* number of refcount table clusters */ + int64_t blocks = 0; /* number of refcount block clusters */ + int64_t last; + int64_t n = 0; + + do { + last = n; + blocks = DIV_ROUND_UP(clusters + table + blocks, refcounts_per_block); + table = DIV_ROUND_UP(blocks, blocks_per_table_cluster); + n = clusters + blocks + table; + + if (n == last && generous_increase) { + clusters += DIV_ROUND_UP(table, 2); + n = 0; /* force another loop */ + generous_increase = false; + } + } while (n != last); + + if (refblock_count) { + *refblock_count = blocks; + } + + return (blocks + table) * cluster_size; +} + +/** + * qcow2_calc_prealloc_size: + * @total_size: virtual disk size in bytes + * @cluster_size: cluster size in bytes + * @refcount_order: refcount bits power-of-2 exponent + * @extended_l2: true if the image has extended L2 entries + * + * Returns: Total number of bytes required for the fully allocated image + * (including metadata). + */ +static int64_t qcow2_calc_prealloc_size(int64_t total_size, + size_t cluster_size, + int refcount_order, + bool extended_l2) +{ + int64_t meta_size = 0; + uint64_t nl1e, nl2e; + int64_t aligned_total_size = ROUND_UP(total_size, cluster_size); + size_t l2e_size = extended_l2 ? L2E_SIZE_EXTENDED : L2E_SIZE_NORMAL; + + /* header: 1 cluster */ + meta_size += cluster_size; + + /* total size of L2 tables */ + nl2e = aligned_total_size / cluster_size; + nl2e = ROUND_UP(nl2e, cluster_size / l2e_size); + meta_size += nl2e * l2e_size; + + /* total size of L1 tables */ + nl1e = nl2e * l2e_size / cluster_size; + nl1e = ROUND_UP(nl1e, cluster_size / L1E_SIZE); + meta_size += nl1e * L1E_SIZE; + + /* total size of refcount table and blocks */ + meta_size += qcow2_refcount_metadata_size( + (meta_size + aligned_total_size) / cluster_size, + cluster_size, refcount_order, false, NULL); + + return meta_size + aligned_total_size; +} + +static bool validate_cluster_size(size_t cluster_size, bool extended_l2, + Error **errp) +{ + int 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 false; + } + + if (extended_l2) { + unsigned min_cluster_size = + (1 << MIN_CLUSTER_BITS) * QCOW_EXTL2_SUBCLUSTERS_PER_CLUSTER; + if (cluster_size < min_cluster_size) { + error_setg(errp, "Extended L2 entries are only supported with " + "cluster sizes of at least %u bytes", min_cluster_size); + return false; + } + } + + return true; +} + +static size_t qcow2_opt_get_cluster_size_del(QemuOpts *opts, bool extended_l2, + Error **errp) +{ + size_t cluster_size; + + cluster_size = qemu_opt_get_size_del(opts, BLOCK_OPT_CLUSTER_SIZE, + DEFAULT_CLUSTER_SIZE); + if (!validate_cluster_size(cluster_size, extended_l2, errp)) { + return 0; + } + return cluster_size; +} + +static int qcow2_opt_get_version_del(QemuOpts *opts, Error **errp) +{ + char *buf; + int ret; + + buf = qemu_opt_get_del(opts, BLOCK_OPT_COMPAT_LEVEL); + if (!buf) { + ret = 3; /* default */ + } else if (!strcmp(buf, "0.10")) { + ret = 2; + } else if (!strcmp(buf, "1.1")) { + ret = 3; + } else { + error_setg(errp, "Invalid compatibility level: '%s'", buf); + ret = -EINVAL; + } + g_free(buf); + return ret; +} + +static uint64_t qcow2_opt_get_refcount_bits_del(QemuOpts *opts, int version, + Error **errp) +{ + uint64_t refcount_bits; + + refcount_bits = qemu_opt_get_number_del(opts, BLOCK_OPT_REFCOUNT_BITS, 16); + 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"); + return 0; + } + + 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)"); + return 0; + } + + return refcount_bits; +} + +static int coroutine_fn +qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp) +{ + BlockdevCreateOptionsQcow2 *qcow2_opts; + QDict *options; + + /* + * 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 second 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 = NULL; + BlockDriverState *bs = NULL; + BlockDriverState *data_bs = NULL; + QCowHeader *header; + size_t cluster_size; + int version; + int refcount_order; + uint64_t *refcount_table; + int ret; + uint8_t compression_type = QCOW2_COMPRESSION_TYPE_ZLIB; + + assert(create_options->driver == BLOCKDEV_DRIVER_QCOW2); + qcow2_opts = &create_options->u.qcow2; + + bs = bdrv_open_blockdev_ref(qcow2_opts->file, errp); + if (bs == NULL) { + return -EIO; + } + + /* Validate options and set default values */ + if (!QEMU_IS_ALIGNED(qcow2_opts->size, BDRV_SECTOR_SIZE)) { + error_setg(errp, "Image size must be a multiple of %u bytes", + (unsigned) BDRV_SECTOR_SIZE); + ret = -EINVAL; + goto out; + } + + if (qcow2_opts->has_version) { + switch (qcow2_opts->version) { + case BLOCKDEV_QCOW2_VERSION_V2: + version = 2; + break; + case BLOCKDEV_QCOW2_VERSION_V3: + version = 3; + break; + default: + g_assert_not_reached(); + } + } else { + version = 3; + } + + if (qcow2_opts->has_cluster_size) { + cluster_size = qcow2_opts->cluster_size; + } else { + cluster_size = DEFAULT_CLUSTER_SIZE; + } + + if (!qcow2_opts->has_extended_l2) { + qcow2_opts->extended_l2 = false; + } + if (qcow2_opts->extended_l2) { + if (version < 3) { + error_setg(errp, "Extended L2 entries are only supported with " + "compatibility level 1.1 and above (use version=v3 or " + "greater)"); + ret = -EINVAL; + goto out; + } + } + + if (!validate_cluster_size(cluster_size, qcow2_opts->extended_l2, errp)) { + ret = -EINVAL; + goto out; + } + + if (!qcow2_opts->has_preallocation) { + qcow2_opts->preallocation = PREALLOC_MODE_OFF; + } + if (qcow2_opts->has_backing_file && + qcow2_opts->preallocation != PREALLOC_MODE_OFF && + !qcow2_opts->extended_l2) + { + error_setg(errp, "Backing file and preallocation can only be used at " + "the same time if extended_l2 is on"); + ret = -EINVAL; + goto out; + } + if (qcow2_opts->has_backing_fmt && !qcow2_opts->has_backing_file) { + error_setg(errp, "Backing format cannot be used without backing file"); + ret = -EINVAL; + goto out; + } + + if (!qcow2_opts->has_lazy_refcounts) { + qcow2_opts->lazy_refcounts = false; + } + if (version < 3 && qcow2_opts->lazy_refcounts) { + error_setg(errp, "Lazy refcounts only supported with compatibility " + "level 1.1 and above (use version=v3 or greater)"); + ret = -EINVAL; + goto out; + } + + if (!qcow2_opts->has_refcount_bits) { + qcow2_opts->refcount_bits = 16; + } + if (qcow2_opts->refcount_bits > 64 || + !is_power_of_2(qcow2_opts->refcount_bits)) + { + error_setg(errp, "Refcount width must be a power of two and may not " + "exceed 64 bits"); + ret = -EINVAL; + goto out; + } + if (version < 3 && qcow2_opts->refcount_bits != 16) { + error_setg(errp, "Different refcount widths than 16 bits require " + "compatibility level 1.1 or above (use version=v3 or " + "greater)"); + ret = -EINVAL; + goto out; + } + refcount_order = ctz32(qcow2_opts->refcount_bits); + + if (qcow2_opts->data_file_raw && !qcow2_opts->data_file) { + error_setg(errp, "data-file-raw requires data-file"); + ret = -EINVAL; + goto out; + } + if (qcow2_opts->data_file_raw && qcow2_opts->has_backing_file) { + error_setg(errp, "Backing file and data-file-raw cannot be used at " + "the same time"); + ret = -EINVAL; + goto out; + } + if (qcow2_opts->data_file_raw && + qcow2_opts->preallocation == PREALLOC_MODE_OFF) + { + /* + * data-file-raw means that "the external data file can be + * read as a consistent standalone raw image without looking + * at the qcow2 metadata." It does not say that the metadata + * must be ignored, though (and the qcow2 driver in fact does + * not ignore it), so the L1/L2 tables must be present and + * give a 1:1 mapping, so you get the same result regardless + * of whether you look at the metadata or whether you ignore + * it. + */ + qcow2_opts->preallocation = PREALLOC_MODE_METADATA; + + /* + * Cannot use preallocation with backing files, but giving a + * backing file when specifying data_file_raw is an error + * anyway. + */ + assert(!qcow2_opts->has_backing_file); + } + + if (qcow2_opts->data_file) { + if (version < 3) { + error_setg(errp, "External data files are only supported with " + "compatibility level 1.1 and above (use version=v3 or " + "greater)"); + ret = -EINVAL; + goto out; + } + data_bs = bdrv_open_blockdev_ref(qcow2_opts->data_file, errp); + if (data_bs == NULL) { + ret = -EIO; + goto out; + } + } + + if (qcow2_opts->has_compression_type && + qcow2_opts->compression_type != QCOW2_COMPRESSION_TYPE_ZLIB) { + + ret = -EINVAL; + + if (version < 3) { + error_setg(errp, "Non-zlib compression type is only supported with " + "compatibility level 1.1 and above (use version=v3 or " + "greater)"); + goto out; + } + + switch (qcow2_opts->compression_type) { +#ifdef CONFIG_ZSTD + case QCOW2_COMPRESSION_TYPE_ZSTD: + break; +#endif + default: + error_setg(errp, "Unknown compression type"); + goto out; + } + + compression_type = qcow2_opts->compression_type; + } + + /* Create BlockBackend to write to the image */ + blk = blk_new_with_bs(bs, BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL, + errp); + if (!blk) { + ret = -EPERM; + goto out; + } + 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(ctz32(cluster_size)), + .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), + /* don't deal with endianness since compression_type is 1 byte long */ + .compression_type = compression_type, + .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 (qcow2_opts->lazy_refcounts) { + header->compatible_features |= + cpu_to_be64(QCOW2_COMPAT_LAZY_REFCOUNTS); + } + if (data_bs) { + header->incompatible_features |= + cpu_to_be64(QCOW2_INCOMPAT_DATA_FILE); + } + if (qcow2_opts->data_file_raw) { + header->autoclear_features |= + cpu_to_be64(QCOW2_AUTOCLEAR_DATA_FILE_RAW); + } + if (compression_type != QCOW2_COMPRESSION_TYPE_ZLIB) { + header->incompatible_features |= + cpu_to_be64(QCOW2_INCOMPAT_COMPRESSION); + } + + if (qcow2_opts->extended_l2) { + header->incompatible_features |= + cpu_to_be64(QCOW2_INCOMPAT_EXTL2); + } + + 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"); + qdict_put_str(options, "file", bs->node_name); + if (data_bs) { + qdict_put_str(options, "data-file", data_bs->node_name); + } + blk = blk_new_open(NULL, NULL, options, + BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_NO_FLUSH, + errp); + if (blk == NULL) { + 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(); + } + + /* Set the external data file if necessary */ + if (data_bs) { + BDRVQcow2State *s = blk_bs(blk)->opaque; + s->image_data_file = g_strdup(data_bs->filename); + } + + /* 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, qcow2_opts->size, false, qcow2_opts->preallocation, + 0, errp); + if (ret < 0) { + error_prepend(errp, "Could not resize image: "); + goto out; + } + + /* Want a backing file? There you go. */ + if (qcow2_opts->has_backing_file) { + const char *backing_format = NULL; + + if (qcow2_opts->has_backing_fmt) { + backing_format = BlockdevDriver_str(qcow2_opts->backing_fmt); + } + + ret = bdrv_change_backing_file(blk_bs(blk), qcow2_opts->backing_file, + backing_format, false); + if (ret < 0) { + error_setg_errno(errp, -ret, "Could not assign backing file '%s' " + "with format '%s'", qcow2_opts->backing_file, + backing_format); + goto out; + } + } + + /* Want encryption? There you go. */ + if (qcow2_opts->has_encrypt) { + ret = qcow2_set_up_encryption(blk_bs(blk), qcow2_opts->encrypt, errp); + if (ret < 0) { + 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"); + qdict_put_str(options, "file", bs->node_name); + if (data_bs) { + qdict_put_str(options, "data-file", data_bs->node_name); + } + blk = blk_new_open(NULL, NULL, options, + BDRV_O_RDWR | BDRV_O_NO_BACKING | BDRV_O_NO_IO, + errp); + if (blk == NULL) { + ret = -EIO; + goto out; + } + + ret = 0; +out: + blk_unref(blk); + bdrv_unref(bs); + bdrv_unref(data_bs); + return ret; +} + +static int coroutine_fn qcow2_co_create_opts(BlockDriver *drv, + const char *filename, + QemuOpts *opts, + Error **errp) +{ + BlockdevCreateOptions *create_options = NULL; + QDict *qdict; + Visitor *v; + BlockDriverState *bs = NULL; + BlockDriverState *data_bs = NULL; + const char *val; + int ret; + + /* Only the keyval visitor supports the dotted syntax needed for + * encryption, so go through a QDict before getting a QAPI type. Ignore + * options meant for the protocol layer so that the visitor doesn't + * complain. */ + qdict = qemu_opts_to_qdict_filtered(opts, NULL, bdrv_qcow2.create_opts, + true); + + /* Handle encryption options */ + val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT); + if (val && !strcmp(val, "on")) { + qdict_put_str(qdict, BLOCK_OPT_ENCRYPT, "qcow"); + } else if (val && !strcmp(val, "off")) { + qdict_del(qdict, BLOCK_OPT_ENCRYPT); + } + + val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT); + if (val && !strcmp(val, "aes")) { + qdict_put_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT, "qcow"); + } + + /* Convert compat=0.10/1.1 into compat=v2/v3, to be renamed into + * version=v2/v3 below. */ + val = qdict_get_try_str(qdict, BLOCK_OPT_COMPAT_LEVEL); + if (val && !strcmp(val, "0.10")) { + qdict_put_str(qdict, BLOCK_OPT_COMPAT_LEVEL, "v2"); + } else if (val && !strcmp(val, "1.1")) { + qdict_put_str(qdict, BLOCK_OPT_COMPAT_LEVEL, "v3"); + } + + /* Change legacy command line options into QMP ones */ + static const QDictRenames opt_renames[] = { + { BLOCK_OPT_BACKING_FILE, "backing-file" }, + { BLOCK_OPT_BACKING_FMT, "backing-fmt" }, + { BLOCK_OPT_CLUSTER_SIZE, "cluster-size" }, + { BLOCK_OPT_LAZY_REFCOUNTS, "lazy-refcounts" }, + { BLOCK_OPT_EXTL2, "extended-l2" }, + { BLOCK_OPT_REFCOUNT_BITS, "refcount-bits" }, + { BLOCK_OPT_ENCRYPT, BLOCK_OPT_ENCRYPT_FORMAT }, + { BLOCK_OPT_COMPAT_LEVEL, "version" }, + { BLOCK_OPT_DATA_FILE_RAW, "data-file-raw" }, + { BLOCK_OPT_COMPRESSION_TYPE, "compression-type" }, + { NULL, NULL }, + }; + + if (!qdict_rename_keys(qdict, opt_renames, errp)) { + ret = -EINVAL; + goto finish; + } + + /* Create and open the file (protocol layer) */ + ret = bdrv_create_file(filename, opts, errp); + if (ret < 0) { + goto finish; + } + + bs = bdrv_open(filename, NULL, NULL, + BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp); + if (bs == NULL) { + ret = -EIO; + goto finish; + } + + /* Create and open an external data file (protocol layer) */ + val = qdict_get_try_str(qdict, BLOCK_OPT_DATA_FILE); + if (val) { + ret = bdrv_create_file(val, opts, errp); + if (ret < 0) { + goto finish; + } + + data_bs = bdrv_open(val, NULL, NULL, + BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, + errp); + if (data_bs == NULL) { + ret = -EIO; + goto finish; + } + + qdict_del(qdict, BLOCK_OPT_DATA_FILE); + qdict_put_str(qdict, "data-file", data_bs->node_name); + } + + /* Set 'driver' and 'node' options */ + qdict_put_str(qdict, "driver", "qcow2"); + qdict_put_str(qdict, "file", bs->node_name); + + /* Now get the QAPI type BlockdevCreateOptions */ + v = qobject_input_visitor_new_flat_confused(qdict, errp); + if (!v) { + ret = -EINVAL; + goto finish; + } + + visit_type_BlockdevCreateOptions(v, NULL, &create_options, errp); + visit_free(v); + if (!create_options) { + ret = -EINVAL; + goto finish; + } + + /* Silently round up size */ + create_options->u.qcow2.size = ROUND_UP(create_options->u.qcow2.size, + BDRV_SECTOR_SIZE); + + /* Create the qcow2 image (format layer) */ + ret = qcow2_co_create(create_options, errp); +finish: + if (ret < 0) { + bdrv_co_delete_file_noerr(bs); + bdrv_co_delete_file_noerr(data_bs); + } else { + ret = 0; + } + + qobject_unref(qdict); + bdrv_unref(bs); + bdrv_unref(data_bs); + qapi_free_BlockdevCreateOptions(create_options); + return ret; +} + + +static bool is_zero(BlockDriverState *bs, int64_t offset, int64_t bytes) +{ + int64_t nr; + int res; + + /* Clamp to image length, before checking status of underlying sectors */ + if (offset + bytes > bs->total_sectors * BDRV_SECTOR_SIZE) { + bytes = bs->total_sectors * BDRV_SECTOR_SIZE - offset; + } + + if (!bytes) { + return true; + } + + /* + * bdrv_block_status_above doesn't merge different types of zeros, for + * example, zeros which come from the region which is unallocated in + * the whole backing chain, and zeros which come because of a short + * backing file. So, we need a loop. + */ + do { + res = bdrv_block_status_above(bs, NULL, offset, bytes, &nr, NULL, NULL); + offset += nr; + bytes -= nr; + } while (res >= 0 && (res & BDRV_BLOCK_ZERO) && nr && bytes); + + return res >= 0 && (res & BDRV_BLOCK_ZERO) && bytes == 0; +} + +static coroutine_fn int qcow2_co_pwrite_zeroes(BlockDriverState *bs, + int64_t offset, int64_t bytes, BdrvRequestFlags flags) +{ + int ret; + BDRVQcow2State *s = bs->opaque; + + uint32_t head = offset_into_subcluster(s, offset); + uint32_t tail = ROUND_UP(offset + bytes, s->subcluster_size) - + (offset + bytes); + + 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) { + uint64_t off; + unsigned int nr; + QCow2SubclusterType type; + + assert(head + bytes + tail <= s->subcluster_size); + + /* check whether remainder of cluster already reads as zero */ + if (!(is_zero(bs, offset - head, head) && + is_zero(bs, offset + bytes, tail))) { + return -ENOTSUP; + } + + qemu_co_mutex_lock(&s->lock); + /* We can have new write after previous check */ + offset -= head; + bytes = s->subcluster_size; + nr = s->subcluster_size; + ret = qcow2_get_host_offset(bs, offset, &nr, &off, &type); + if (ret < 0 || + (type != QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN && + type != QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC && + type != QCOW2_SUBCLUSTER_ZERO_PLAIN && + type != QCOW2_SUBCLUSTER_ZERO_ALLOC)) { + qemu_co_mutex_unlock(&s->lock); + return ret < 0 ? ret : -ENOTSUP; + } + } else { + qemu_co_mutex_lock(&s->lock); + } + + trace_qcow2_pwrite_zeroes(qemu_coroutine_self(), offset, bytes); + + /* Whatever is left can use real zero subclusters */ + ret = qcow2_subcluster_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, int64_t bytes) +{ + int ret; + BDRVQcow2State *s = bs->opaque; + + /* If the image does not support QCOW_OFLAG_ZERO then discarding + * clusters could expose stale data from the backing file. */ + if (s->qcow_version < 3 && bs->backing) { + return -ENOTSUP; + } + + 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 coroutine_fn +qcow2_co_copy_range_from(BlockDriverState *bs, + BdrvChild *src, int64_t src_offset, + BdrvChild *dst, int64_t dst_offset, + int64_t bytes, BdrvRequestFlags read_flags, + BdrvRequestFlags write_flags) +{ + BDRVQcow2State *s = bs->opaque; + int ret; + unsigned int cur_bytes; /* number of bytes in current iteration */ + BdrvChild *child = NULL; + BdrvRequestFlags cur_write_flags; + + assert(!bs->encrypted); + qemu_co_mutex_lock(&s->lock); + + while (bytes != 0) { + uint64_t copy_offset = 0; + QCow2SubclusterType type; + /* prepare next request */ + cur_bytes = MIN(bytes, INT_MAX); + cur_write_flags = write_flags; + + ret = qcow2_get_host_offset(bs, src_offset, &cur_bytes, + ©_offset, &type); + if (ret < 0) { + goto out; + } + + switch (type) { + case QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN: + case QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC: + if (bs->backing && bs->backing->bs) { + int64_t backing_length = bdrv_getlength(bs->backing->bs); + if (src_offset >= backing_length) { + cur_write_flags |= BDRV_REQ_ZERO_WRITE; + } else { + child = bs->backing; + cur_bytes = MIN(cur_bytes, backing_length - src_offset); + copy_offset = src_offset; + } + } else { + cur_write_flags |= BDRV_REQ_ZERO_WRITE; + } + break; + + case QCOW2_SUBCLUSTER_ZERO_PLAIN: + case QCOW2_SUBCLUSTER_ZERO_ALLOC: + cur_write_flags |= BDRV_REQ_ZERO_WRITE; + break; + + case QCOW2_SUBCLUSTER_COMPRESSED: + ret = -ENOTSUP; + goto out; + + case QCOW2_SUBCLUSTER_NORMAL: + child = s->data_file; + break; + + default: + abort(); + } + qemu_co_mutex_unlock(&s->lock); + ret = bdrv_co_copy_range_from(child, + copy_offset, + dst, dst_offset, + cur_bytes, read_flags, cur_write_flags); + qemu_co_mutex_lock(&s->lock); + if (ret < 0) { + goto out; + } + + bytes -= cur_bytes; + src_offset += cur_bytes; + dst_offset += cur_bytes; + } + ret = 0; + +out: + qemu_co_mutex_unlock(&s->lock); + return ret; +} + +static int coroutine_fn +qcow2_co_copy_range_to(BlockDriverState *bs, + BdrvChild *src, int64_t src_offset, + BdrvChild *dst, int64_t dst_offset, + int64_t bytes, BdrvRequestFlags read_flags, + BdrvRequestFlags write_flags) +{ + BDRVQcow2State *s = bs->opaque; + int ret; + unsigned int cur_bytes; /* number of sectors in current iteration */ + uint64_t host_offset; + QCowL2Meta *l2meta = NULL; + + assert(!bs->encrypted); + + qemu_co_mutex_lock(&s->lock); + + while (bytes != 0) { + + l2meta = NULL; + + cur_bytes = MIN(bytes, INT_MAX); + + /* TODO: + * If src->bs == dst->bs, we could simply copy by incrementing + * the refcnt, without copying user data. + * Or if src->bs == dst->bs->backing->bs, we could copy by discarding. */ + ret = qcow2_alloc_host_offset(bs, dst_offset, &cur_bytes, + &host_offset, &l2meta); + if (ret < 0) { + goto fail; + } + + ret = qcow2_pre_write_overlap_check(bs, 0, host_offset, cur_bytes, + true); + if (ret < 0) { + goto fail; + } + + qemu_co_mutex_unlock(&s->lock); + ret = bdrv_co_copy_range_to(src, src_offset, s->data_file, host_offset, + cur_bytes, read_flags, write_flags); + qemu_co_mutex_lock(&s->lock); + if (ret < 0) { + goto fail; + } + + ret = qcow2_handle_l2meta(bs, &l2meta, true); + if (ret) { + goto fail; + } + + bytes -= cur_bytes; + src_offset += cur_bytes; + dst_offset += cur_bytes; + } + ret = 0; + +fail: + qcow2_handle_l2meta(bs, &l2meta, false); + + qemu_co_mutex_unlock(&s->lock); + + trace_qcow2_writev_done_req(qemu_coroutine_self(), ret); + + return ret; +} + +static int coroutine_fn qcow2_co_truncate(BlockDriverState *bs, int64_t offset, + bool exact, PreallocMode prealloc, + BdrvRequestFlags flags, Error **errp) +{ + BDRVQcow2State *s = bs->opaque; + uint64_t old_length; + int64_t new_l1_size; + int ret; + QDict *options; + + if (prealloc != PREALLOC_MODE_OFF && prealloc != PREALLOC_MODE_METADATA && + prealloc != PREALLOC_MODE_FALLOC && prealloc != PREALLOC_MODE_FULL) + { + error_setg(errp, "Unsupported preallocation mode '%s'", + PreallocMode_str(prealloc)); + return -ENOTSUP; + } + + if (!QEMU_IS_ALIGNED(offset, BDRV_SECTOR_SIZE)) { + error_setg(errp, "The new size must be a multiple of %u", + (unsigned) BDRV_SECTOR_SIZE); + return -EINVAL; + } + + qemu_co_mutex_lock(&s->lock); + + /* + * Even though we store snapshot size for all images, it was not + * required until v3, so it is not safe to proceed for v2. + */ + if (s->nb_snapshots && s->qcow_version < 3) { + error_setg(errp, "Can't resize a v2 image which has snapshots"); + ret = -ENOTSUP; + goto fail; + } + + /* See qcow2-bitmap.c for which bitmap scenarios prevent a resize. */ + if (qcow2_truncate_bitmaps_check(bs, errp)) { + ret = -ENOTSUP; + goto fail; + } + + old_length = bs->total_sectors * BDRV_SECTOR_SIZE; + new_l1_size = size_to_l1(s, offset); + + if (offset < old_length) { + int64_t last_cluster, old_file_size; + if (prealloc != PREALLOC_MODE_OFF) { + error_setg(errp, + "Preallocation can't be used for shrinking an image"); + ret = -EINVAL; + goto fail; + } + + ret = qcow2_cluster_discard(bs, ROUND_UP(offset, s->cluster_size), + old_length - ROUND_UP(offset, + s->cluster_size), + QCOW2_DISCARD_ALWAYS, true); + if (ret < 0) { + error_setg_errno(errp, -ret, "Failed to discard cropped clusters"); + goto fail; + } + + ret = qcow2_shrink_l1_table(bs, new_l1_size); + if (ret < 0) { + error_setg_errno(errp, -ret, + "Failed to reduce the number of L2 tables"); + goto fail; + } + + ret = qcow2_shrink_reftable(bs); + if (ret < 0) { + error_setg_errno(errp, -ret, + "Failed to discard unused refblocks"); + goto fail; + } + + old_file_size = bdrv_getlength(bs->file->bs); + if (old_file_size < 0) { + error_setg_errno(errp, -old_file_size, + "Failed to inquire current file length"); + ret = old_file_size; + goto fail; + } + last_cluster = qcow2_get_last_cluster(bs, old_file_size); + if (last_cluster < 0) { + error_setg_errno(errp, -last_cluster, + "Failed to find the last cluster"); + ret = last_cluster; + goto fail; + } + if ((last_cluster + 1) * s->cluster_size < old_file_size) { + Error *local_err = NULL; + + /* + * Do not pass @exact here: It will not help the user if + * we get an error here just because they wanted to shrink + * their qcow2 image (on a block device) with qemu-img. + * (And on the qcow2 layer, the @exact requirement is + * always fulfilled, so there is no need to pass it on.) + */ + bdrv_co_truncate(bs->file, (last_cluster + 1) * s->cluster_size, + false, PREALLOC_MODE_OFF, 0, &local_err); + if (local_err) { + warn_reportf_err(local_err, + "Failed to truncate the tail of the image: "); + } + } + } else { + ret = qcow2_grow_l1_table(bs, new_l1_size, true); + if (ret < 0) { + error_setg_errno(errp, -ret, "Failed to grow the L1 table"); + goto fail; + } + + if (data_file_is_raw(bs) && prealloc == PREALLOC_MODE_OFF) { + /* + * When creating a qcow2 image with data-file-raw, we enforce + * at least prealloc=metadata, so that the L1/L2 tables are + * fully allocated and reading from the data file will return + * the same data as reading from the qcow2 image. When the + * image is grown, we must consequently preallocate the + * metadata structures to cover the added area. + */ + prealloc = PREALLOC_MODE_METADATA; + } + } + + switch (prealloc) { + case PREALLOC_MODE_OFF: + if (has_data_file(bs)) { + /* + * If the caller wants an exact resize, the external data + * file should be resized to the exact target size, too, + * so we pass @exact here. + */ + ret = bdrv_co_truncate(s->data_file, offset, exact, prealloc, 0, + errp); + if (ret < 0) { + goto fail; + } + } + break; + + case PREALLOC_MODE_METADATA: + ret = preallocate_co(bs, old_length, offset, prealloc, errp); + if (ret < 0) { + goto fail; + } + break; + + case PREALLOC_MODE_FALLOC: + case PREALLOC_MODE_FULL: + { + int64_t allocation_start, host_offset, guest_offset; + int64_t clusters_allocated; + int64_t old_file_size, last_cluster, new_file_size; + uint64_t nb_new_data_clusters, nb_new_l2_tables; + bool subclusters_need_allocation = false; + + /* With a data file, preallocation means just allocating the metadata + * and forwarding the truncate request to the data file */ + if (has_data_file(bs)) { + ret = preallocate_co(bs, old_length, offset, prealloc, errp); + if (ret < 0) { + goto fail; + } + break; + } + + old_file_size = bdrv_getlength(bs->file->bs); + if (old_file_size < 0) { + error_setg_errno(errp, -old_file_size, + "Failed to inquire current file length"); + ret = old_file_size; + goto fail; + } + + last_cluster = qcow2_get_last_cluster(bs, old_file_size); + if (last_cluster >= 0) { + old_file_size = (last_cluster + 1) * s->cluster_size; + } else { + old_file_size = ROUND_UP(old_file_size, s->cluster_size); + } + + nb_new_data_clusters = (ROUND_UP(offset, s->cluster_size) - + start_of_cluster(s, old_length)) >> s->cluster_bits; + + /* This is an overestimation; we will not actually allocate space for + * these in the file but just make sure the new refcount structures are + * able to cover them so we will not have to allocate new refblocks + * while entering the data blocks in the potentially new L2 tables. + * (We do not actually care where the L2 tables are placed. Maybe they + * are already allocated or they can be placed somewhere before + * @old_file_size. It does not matter because they will be fully + * allocated automatically, so they do not need to be covered by the + * preallocation. All that matters is that we will not have to allocate + * new refcount structures for them.) */ + nb_new_l2_tables = DIV_ROUND_UP(nb_new_data_clusters, + s->cluster_size / l2_entry_size(s)); + /* The cluster range may not be aligned to L2 boundaries, so add one L2 + * table for a potential head/tail */ + nb_new_l2_tables++; + + allocation_start = qcow2_refcount_area(bs, old_file_size, + nb_new_data_clusters + + nb_new_l2_tables, + true, 0, 0); + if (allocation_start < 0) { + error_setg_errno(errp, -allocation_start, + "Failed to resize refcount structures"); + ret = allocation_start; + goto fail; + } + + clusters_allocated = qcow2_alloc_clusters_at(bs, allocation_start, + nb_new_data_clusters); + if (clusters_allocated < 0) { + error_setg_errno(errp, -clusters_allocated, + "Failed to allocate data clusters"); + ret = clusters_allocated; + goto fail; + } + + assert(clusters_allocated == nb_new_data_clusters); + + /* Allocate the data area */ + new_file_size = allocation_start + + nb_new_data_clusters * s->cluster_size; + /* + * Image file grows, so @exact does not matter. + * + * If we need to zero out the new area, try first whether the protocol + * driver can already take care of this. + */ + if (flags & BDRV_REQ_ZERO_WRITE) { + ret = bdrv_co_truncate(bs->file, new_file_size, false, prealloc, + BDRV_REQ_ZERO_WRITE, NULL); + if (ret >= 0) { + flags &= ~BDRV_REQ_ZERO_WRITE; + /* Ensure that we read zeroes and not backing file data */ + subclusters_need_allocation = true; + } + } else { + ret = -1; + } + if (ret < 0) { + ret = bdrv_co_truncate(bs->file, new_file_size, false, prealloc, 0, + errp); + } + if (ret < 0) { + error_prepend(errp, "Failed to resize underlying file: "); + qcow2_free_clusters(bs, allocation_start, + nb_new_data_clusters * s->cluster_size, + QCOW2_DISCARD_OTHER); + goto fail; + } + + /* Create the necessary L2 entries */ + host_offset = allocation_start; + guest_offset = old_length; + while (nb_new_data_clusters) { + int64_t nb_clusters = MIN( + nb_new_data_clusters, + s->l2_slice_size - offset_to_l2_slice_index(s, guest_offset)); + unsigned cow_start_length = offset_into_cluster(s, guest_offset); + QCowL2Meta allocation; + guest_offset = start_of_cluster(s, guest_offset); + allocation = (QCowL2Meta) { + .offset = guest_offset, + .alloc_offset = host_offset, + .nb_clusters = nb_clusters, + .cow_start = { + .offset = 0, + .nb_bytes = cow_start_length, + }, + .cow_end = { + .offset = nb_clusters << s->cluster_bits, + .nb_bytes = 0, + }, + .prealloc = !subclusters_need_allocation, + }; + qemu_co_queue_init(&allocation.dependent_requests); + + ret = qcow2_alloc_cluster_link_l2(bs, &allocation); + if (ret < 0) { + error_setg_errno(errp, -ret, "Failed to update L2 tables"); + qcow2_free_clusters(bs, host_offset, + nb_new_data_clusters * s->cluster_size, + QCOW2_DISCARD_OTHER); + goto fail; + } + + guest_offset += nb_clusters * s->cluster_size; + host_offset += nb_clusters * s->cluster_size; + nb_new_data_clusters -= nb_clusters; + } + break; + } + + default: + g_assert_not_reached(); + } + + if ((flags & BDRV_REQ_ZERO_WRITE) && offset > old_length) { + uint64_t zero_start = QEMU_ALIGN_UP(old_length, s->subcluster_size); + + /* + * Use zero clusters as much as we can. qcow2_subcluster_zeroize() + * requires a subcluster-aligned start. The end may be unaligned if + * it is at the end of the image (which it is here). + */ + if (offset > zero_start) { + ret = qcow2_subcluster_zeroize(bs, zero_start, offset - zero_start, + 0); + if (ret < 0) { + error_setg_errno(errp, -ret, "Failed to zero out new clusters"); + goto fail; + } + } + + /* Write explicit zeros for the unaligned head */ + if (zero_start > old_length) { + uint64_t len = MIN(zero_start, offset) - old_length; + uint8_t *buf = qemu_blockalign0(bs, len); + QEMUIOVector qiov; + qemu_iovec_init_buf(&qiov, buf, len); + + qemu_co_mutex_unlock(&s->lock); + ret = qcow2_co_pwritev_part(bs, old_length, len, &qiov, 0, 0); + qemu_co_mutex_lock(&s->lock); + + qemu_vfree(buf); + if (ret < 0) { + error_setg_errno(errp, -ret, "Failed to zero out the new area"); + goto fail; + } + } + } + + if (prealloc != PREALLOC_MODE_OFF) { + /* Flush metadata before actually changing the image size */ + ret = qcow2_write_caches(bs); + if (ret < 0) { + error_setg_errno(errp, -ret, + "Failed to flush the preallocated area to disk"); + goto fail; + } + } + + bs->total_sectors = offset / BDRV_SECTOR_SIZE; + + /* write updated header.size */ + offset = cpu_to_be64(offset); + ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, size), + &offset, sizeof(offset)); + if (ret < 0) { + error_setg_errno(errp, -ret, "Failed to update the image size"); + goto fail; + } + + s->l1_vm_state_index = new_l1_size; + + /* Update cache sizes */ + options = qdict_clone_shallow(bs->options); + ret = qcow2_update_options(bs, options, s->flags, errp); + qobject_unref(options); + if (ret < 0) { + goto fail; + } + ret = 0; +fail: + qemu_co_mutex_unlock(&s->lock); + return ret; +} + +static coroutine_fn int +qcow2_co_pwritev_compressed_task(BlockDriverState *bs, + uint64_t offset, uint64_t bytes, + QEMUIOVector *qiov, size_t qiov_offset) +{ + BDRVQcow2State *s = bs->opaque; + int ret; + ssize_t out_len; + uint8_t *buf, *out_buf; + uint64_t cluster_offset; + + assert(bytes == s->cluster_size || (bytes < s->cluster_size && + (offset + bytes == bs->total_sectors << BDRV_SECTOR_BITS))); + + buf = qemu_blockalign(bs, s->cluster_size); + if (bytes < s->cluster_size) { + /* Zero-pad last write if image size is not cluster aligned */ + memset(buf + bytes, 0, s->cluster_size - bytes); + } + qemu_iovec_to_buf(qiov, qiov_offset, buf, bytes); + + out_buf = g_malloc(s->cluster_size); + + out_len = qcow2_co_compress(bs, out_buf, s->cluster_size - 1, + buf, s->cluster_size); + if (out_len == -ENOMEM) { + /* could not compress: write normal cluster */ + ret = qcow2_co_pwritev_part(bs, offset, bytes, qiov, qiov_offset, 0); + if (ret < 0) { + goto fail; + } + goto success; + } else if (out_len < 0) { + ret = -EINVAL; + goto fail; + } + + qemu_co_mutex_lock(&s->lock); + ret = qcow2_alloc_compressed_cluster_offset(bs, offset, out_len, + &cluster_offset); + if (ret < 0) { + qemu_co_mutex_unlock(&s->lock); + goto fail; + } + + ret = qcow2_pre_write_overlap_check(bs, 0, cluster_offset, out_len, true); + qemu_co_mutex_unlock(&s->lock); + if (ret < 0) { + goto fail; + } + + BLKDBG_EVENT(s->data_file, BLKDBG_WRITE_COMPRESSED); + ret = bdrv_co_pwrite(s->data_file, cluster_offset, out_len, out_buf, 0); + if (ret < 0) { + goto fail; + } +success: + ret = 0; +fail: + qemu_vfree(buf); + g_free(out_buf); + return ret; +} + +static coroutine_fn int qcow2_co_pwritev_compressed_task_entry(AioTask *task) +{ + Qcow2AioTask *t = container_of(task, Qcow2AioTask, task); + + assert(!t->subcluster_type && !t->l2meta); + + return qcow2_co_pwritev_compressed_task(t->bs, t->offset, t->bytes, t->qiov, + t->qiov_offset); +} + +/* + * 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_part(BlockDriverState *bs, + int64_t offset, int64_t bytes, + QEMUIOVector *qiov, size_t qiov_offset) +{ + BDRVQcow2State *s = bs->opaque; + AioTaskPool *aio = NULL; + int ret = 0; + + if (has_data_file(bs)) { + return -ENOTSUP; + } + + if (bytes == 0) { + /* + * align end of file to a sector boundary to ease reading with + * sector based I/Os + */ + int64_t len = bdrv_getlength(bs->file->bs); + if (len < 0) { + return len; + } + return bdrv_co_truncate(bs->file, len, false, PREALLOC_MODE_OFF, 0, + NULL); + } + + if (offset_into_cluster(s, offset)) { + return -EINVAL; + } + + if (offset_into_cluster(s, bytes) && + (offset + bytes) != (bs->total_sectors << BDRV_SECTOR_BITS)) { + return -EINVAL; + } + + while (bytes && aio_task_pool_status(aio) == 0) { + uint64_t chunk_size = MIN(bytes, s->cluster_size); + + if (!aio && chunk_size != bytes) { + aio = aio_task_pool_new(QCOW2_MAX_WORKERS); + } + + ret = qcow2_add_task(bs, aio, qcow2_co_pwritev_compressed_task_entry, + 0, 0, offset, chunk_size, qiov, qiov_offset, NULL); + if (ret < 0) { + break; + } + qiov_offset += chunk_size; + offset += chunk_size; + bytes -= chunk_size; + } + + if (aio) { + aio_task_pool_wait_all(aio); + if (ret == 0) { + ret = aio_task_pool_status(aio); + } + g_free(aio); + } + + return ret; +} + +static int coroutine_fn +qcow2_co_preadv_compressed(BlockDriverState *bs, + uint64_t l2_entry, + uint64_t offset, + uint64_t bytes, + QEMUIOVector *qiov, + size_t qiov_offset) +{ + BDRVQcow2State *s = bs->opaque; + int ret = 0, csize; + uint64_t coffset; + uint8_t *buf, *out_buf; + int offset_in_cluster = offset_into_cluster(s, offset); + + qcow2_parse_compressed_l2_entry(bs, l2_entry, &coffset, &csize); + + buf = g_try_malloc(csize); + if (!buf) { + return -ENOMEM; + } + + out_buf = qemu_blockalign(bs, s->cluster_size); + + BLKDBG_EVENT(bs->file, BLKDBG_READ_COMPRESSED); + ret = bdrv_co_pread(bs->file, coffset, csize, buf, 0); + if (ret < 0) { + goto fail; + } + + if (qcow2_co_decompress(bs, out_buf, s->cluster_size, buf, csize) < 0) { + ret = -EIO; + goto fail; + } + + qemu_iovec_from_buf(qiov, qiov_offset, out_buf + offset_in_cluster, bytes); + +fail: + qemu_vfree(out_buf); + g_free(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 / L1E_SIZE); + l1_size2 = (uint64_t)s->l1_size * L1E_SIZE; + + /* 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 / REFTABLE_ENTRY_SIZE); + if (!new_reftable) { + ret = -ENOMEM; + goto fail_broken_refcounts; + } + + s->refcount_table_offset = s->cluster_size; + s->refcount_table_size = s->cluster_size / REFTABLE_ENTRY_SIZE; + 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, false, + PREALLOC_MODE_OFF, 0, &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 / L1E_SIZE); + + if (s->qcow_version >= 3 && !s->snapshots && !s->nb_bitmaps && + 3 + l1_clusters <= s->refcount_block_size && + s->crypt_method_header != QCOW_CRYPT_LUKS && + !has_data_file(bs)) { + /* The following function only works for qcow2 v3 images (it + * requires the dirty flag) and only as long as there are no + * features that reserve extra clusters (such as snapshots, + * LUKS header, or persistent bitmaps), 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. It + * only resets the image file, i.e. does not work with an + * external data file. */ + 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_write_caches(bs); + qemu_co_mutex_unlock(&s->lock); + + return ret; +} + +static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs, + Error **errp) +{ + Error *local_err = NULL; + BlockMeasureInfo *info; + uint64_t required = 0; /* bytes that contribute to required size */ + uint64_t virtual_size; /* disk size as seen by guest */ + uint64_t refcount_bits; + uint64_t l2_tables; + uint64_t luks_payload_size = 0; + size_t cluster_size; + int version; + char *optstr; + PreallocMode prealloc; + bool has_backing_file; + bool has_luks; + bool extended_l2; + size_t l2e_size; + + /* Parse image creation options */ + extended_l2 = qemu_opt_get_bool_del(opts, BLOCK_OPT_EXTL2, false); + + cluster_size = qcow2_opt_get_cluster_size_del(opts, extended_l2, + &local_err); + if (local_err) { + goto err; + } + + version = qcow2_opt_get_version_del(opts, &local_err); + if (local_err) { + goto err; + } + + refcount_bits = qcow2_opt_get_refcount_bits_del(opts, version, &local_err); + if (local_err) { + goto err; + } + + optstr = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC); + prealloc = qapi_enum_parse(&PreallocMode_lookup, optstr, + PREALLOC_MODE_OFF, &local_err); + g_free(optstr); + if (local_err) { + goto err; + } + + optstr = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); + has_backing_file = !!optstr; + g_free(optstr); + + optstr = qemu_opt_get_del(opts, BLOCK_OPT_ENCRYPT_FORMAT); + has_luks = optstr && strcmp(optstr, "luks") == 0; + g_free(optstr); + + if (has_luks) { + g_autoptr(QCryptoBlockCreateOptions) create_opts = NULL; + QDict *cryptoopts = qcow2_extract_crypto_opts(opts, "luks", errp); + size_t headerlen; + + create_opts = block_crypto_create_opts_init(cryptoopts, errp); + qobject_unref(cryptoopts); + if (!create_opts) { + goto err; + } + + if (!qcrypto_block_calculate_payload_offset(create_opts, + "encrypt.", + &headerlen, + &local_err)) { + goto err; + } + + luks_payload_size = ROUND_UP(headerlen, cluster_size); + } + + virtual_size = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0); + virtual_size = ROUND_UP(virtual_size, cluster_size); + + /* Check that virtual disk size is valid */ + l2e_size = extended_l2 ? L2E_SIZE_EXTENDED : L2E_SIZE_NORMAL; + l2_tables = DIV_ROUND_UP(virtual_size / cluster_size, + cluster_size / l2e_size); + if (l2_tables * L1E_SIZE > QCOW_MAX_L1_SIZE) { + error_setg(&local_err, "The image size is too large " + "(try using a larger cluster size)"); + goto err; + } + + /* Account for input image */ + if (in_bs) { + int64_t ssize = bdrv_getlength(in_bs); + if (ssize < 0) { + error_setg_errno(&local_err, -ssize, + "Unable to get image virtual_size"); + goto err; + } + + virtual_size = ROUND_UP(ssize, cluster_size); + + if (has_backing_file) { + /* We don't how much of the backing chain is shared by the input + * image and the new image file. In the worst case the new image's + * backing file has nothing in common with the input image. Be + * conservative and assume all clusters need to be written. + */ + required = virtual_size; + } else { + int64_t offset; + int64_t pnum = 0; + + for (offset = 0; offset < ssize; offset += pnum) { + int ret; + + ret = bdrv_block_status_above(in_bs, NULL, offset, + ssize - offset, &pnum, NULL, + NULL); + if (ret < 0) { + error_setg_errno(&local_err, -ret, + "Unable to get block status"); + goto err; + } + + if (ret & BDRV_BLOCK_ZERO) { + /* Skip zero regions (safe with no backing file) */ + } else if ((ret & (BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED)) == + (BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED)) { + /* Extend pnum to end of cluster for next iteration */ + pnum = ROUND_UP(offset + pnum, cluster_size) - offset; + + /* Count clusters we've seen */ + required += offset % cluster_size + pnum; + } + } + } + } + + /* Take into account preallocation. Nothing special is needed for + * PREALLOC_MODE_METADATA since metadata is always counted. + */ + if (prealloc == PREALLOC_MODE_FULL || prealloc == PREALLOC_MODE_FALLOC) { + required = virtual_size; + } + + info = g_new0(BlockMeasureInfo, 1); + info->fully_allocated = luks_payload_size + + qcow2_calc_prealloc_size(virtual_size, cluster_size, + ctz32(refcount_bits), extended_l2); + + /* + * Remove data clusters that are not required. This overestimates the + * required size because metadata needed for the fully allocated file is + * still counted. Show bitmaps only if both source and destination + * would support them. + */ + info->required = info->fully_allocated - virtual_size + required; + info->has_bitmaps = version >= 3 && in_bs && + bdrv_supports_persistent_dirty_bitmap(in_bs); + if (info->has_bitmaps) { + info->bitmaps = qcow2_get_persistent_dirty_bitmap_size(in_bs, + cluster_size); + } + return info; + +err: + error_propagate(errp, local_err); + return NULL; +} + +static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) +{ + BDRVQcow2State *s = bs->opaque; + bdi->cluster_size = s->cluster_size; + bdi->vm_state_offset = qcow2_vm_state_offset(s); + bdi->is_dirty = s->incompatible_features & QCOW2_INCOMPAT_DIRTY; + return 0; +} + +static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs, + Error **errp) +{ + BDRVQcow2State *s = bs->opaque; + ImageInfoSpecific *spec_info; + QCryptoBlockInfo *encrypt_info = NULL; + + if (s->crypto != NULL) { + encrypt_info = qcrypto_block_get_info(s->crypto, errp); + if (!encrypt_info) { + return NULL; + } + } + + spec_info = g_new(ImageInfoSpecific, 1); + *spec_info = (ImageInfoSpecific){ + .type = IMAGE_INFO_SPECIFIC_KIND_QCOW2, + .u.qcow2.data = g_new0(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) { + Qcow2BitmapInfoList *bitmaps; + if (!qcow2_get_bitmap_info_list(bs, &bitmaps, errp)) { + qapi_free_ImageInfoSpecific(spec_info); + qapi_free_QCryptoBlockInfo(encrypt_info); + return NULL; + } + *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, + .has_extended_l2 = true, + .extended_l2 = has_subclusters(s), + .refcount_bits = s->refcount_bits, + .has_bitmaps = !!bitmaps, + .bitmaps = bitmaps, + .has_data_file = !!s->image_data_file, + .data_file = g_strdup(s->image_data_file), + .has_data_file_raw = has_data_file(bs), + .data_file_raw = data_file_is_raw(bs), + .compression_type = s->compression_type, + }; + } else { + /* if this assertion fails, this probably means a new version was + * added without having it covered here */ + assert(false); + } + + if (encrypt_info) { + ImageInfoSpecificQCow2Encryption *qencrypt = + g_new(ImageInfoSpecificQCow2Encryption, 1); + switch (encrypt_info->format) { + case Q_CRYPTO_BLOCK_FORMAT_QCOW: + qencrypt->format = BLOCKDEV_QCOW2_ENCRYPTION_FORMAT_AES; + break; + case Q_CRYPTO_BLOCK_FORMAT_LUKS: + qencrypt->format = BLOCKDEV_QCOW2_ENCRYPTION_FORMAT_LUKS; + qencrypt->u.luks = encrypt_info->u.luks; + break; + default: + abort(); + } + /* Since we did shallow copy above, erase any pointers + * in the original info */ + memset(&encrypt_info->u, 0, sizeof(encrypt_info->u)); + qapi_free_QCryptoBlockInfo(encrypt_info); + + spec_info->u.qcow2.data->has_encrypt = true; + spec_info->u.qcow2.data->encrypt = qencrypt; + } + + return spec_info; +} + +static int qcow2_has_zero_init(BlockDriverState *bs) +{ + BDRVQcow2State *s = bs->opaque; + bool preallocated; + + if (qemu_in_coroutine()) { + qemu_co_mutex_lock(&s->lock); + } + /* + * Check preallocation status: Preallocated images have all L2 + * tables allocated, nonpreallocated images have none. It is + * therefore enough to check the first one. + */ + preallocated = s->l1_size > 0 && s->l1_table[0] != 0; + if (qemu_in_coroutine()) { + qemu_co_mutex_unlock(&s->lock); + } + + if (!preallocated) { + return 1; + } else if (bs->encrypted) { + return 0; + } else { + return bdrv_has_zero_init(s->data_file->bs); + } +} + +/* + * Check the request to vmstate. On success return + * qcow2_vm_state_offset(bs) + @pos + */ +static int64_t qcow2_check_vmstate_request(BlockDriverState *bs, + QEMUIOVector *qiov, int64_t pos) +{ + BDRVQcow2State *s = bs->opaque; + int64_t vmstate_offset = qcow2_vm_state_offset(s); + int ret; + + /* Incoming requests must be OK */ + bdrv_check_qiov_request(pos, qiov->size, qiov, 0, &error_abort); + + if (INT64_MAX - pos < vmstate_offset) { + return -EIO; + } + + pos += vmstate_offset; + ret = bdrv_check_qiov_request(pos, qiov->size, qiov, 0, NULL); + if (ret < 0) { + return ret; + } + + return pos; +} + +static int qcow2_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, + int64_t pos) +{ + int64_t offset = qcow2_check_vmstate_request(bs, qiov, pos); + if (offset < 0) { + return offset; + } + + BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE); + return bs->drv->bdrv_co_pwritev_part(bs, offset, qiov->size, qiov, 0, 0); +} + +static int qcow2_load_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, + int64_t pos) +{ + int64_t offset = qcow2_check_vmstate_request(bs, qiov, pos); + if (offset < 0) { + return offset; + } + + BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD); + return bs->drv->bdrv_co_preadv_part(bs, offset, qiov->size, qiov, 0, 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, + Error **errp) +{ + BDRVQcow2State *s = bs->opaque; + int current_version = s->qcow_version; + int ret; + int i; + + /* This is qcow2_downgrade(), not qcow2_upgrade() */ + assert(target_version < current_version); + + /* There are no other versions (now) that you can downgrade to */ + assert(target_version == 2); + + if (s->refcount_order != 4) { + error_setg(errp, "compat=0.10 requires refcount_bits=16"); + return -ENOTSUP; + } + + if (has_data_file(bs)) { + error_setg(errp, "Cannot downgrade an image with a data file"); + return -ENOTSUP; + } + + /* + * If any internal snapshot has a different size than the current + * image size, or VM state size that exceeds 32 bits, downgrading + * is unsafe. Even though we would still use v3-compliant output + * to preserve that data, other v2 programs might not realize + * those optional fields are important. + */ + for (i = 0; i < s->nb_snapshots; i++) { + if (s->snapshots[i].vm_state_size > UINT32_MAX || + s->snapshots[i].disk_size != bs->total_sectors * BDRV_SECTOR_SIZE) { + error_setg(errp, "Internal snapshots prevent downgrade of image"); + return -ENOTSUP; + } + } + + /* clear incompatible features */ + if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { + ret = qcow2_mark_clean(bs); + if (ret < 0) { + error_setg_errno(errp, -ret, "Failed to make the image clean"); + 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) { + error_setg(errp, "Cannot downgrade an image with incompatible features " + "%#" PRIx64 " set", 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) { + error_setg_errno(errp, -ret, "Failed to turn zero into data clusters"); + return ret; + } + + s->qcow_version = target_version; + ret = qcow2_update_header(bs); + if (ret < 0) { + s->qcow_version = current_version; + error_setg_errno(errp, -ret, "Failed to update the image header"); + return ret; + } + return 0; +} + +/* + * Upgrades an image's version. While newer versions encompass all + * features of older versions, some things may have to be presented + * differently. + */ +static int qcow2_upgrade(BlockDriverState *bs, int target_version, + BlockDriverAmendStatusCB *status_cb, void *cb_opaque, + Error **errp) +{ + BDRVQcow2State *s = bs->opaque; + bool need_snapshot_update; + int current_version = s->qcow_version; + int i; + int ret; + + /* This is qcow2_upgrade(), not qcow2_downgrade() */ + assert(target_version > current_version); + + /* There are no other versions (yet) that you can upgrade to */ + assert(target_version == 3); + + status_cb(bs, 0, 2, cb_opaque); + + /* + * In v2, snapshots do not need to have extra data. v3 requires + * the 64-bit VM state size and the virtual disk size to be + * present. + * qcow2_write_snapshots() will always write the list in the + * v3-compliant format. + */ + need_snapshot_update = false; + for (i = 0; i < s->nb_snapshots; i++) { + if (s->snapshots[i].extra_data_size < + sizeof_field(QCowSnapshotExtraData, vm_state_size_large) + + sizeof_field(QCowSnapshotExtraData, disk_size)) + { + need_snapshot_update = true; + break; + } + } + if (need_snapshot_update) { + ret = qcow2_write_snapshots(bs); + if (ret < 0) { + error_setg_errno(errp, -ret, "Failed to update the snapshot table"); + return ret; + } + } + status_cb(bs, 1, 2, cb_opaque); + + s->qcow_version = target_version; + ret = qcow2_update_header(bs); + if (ret < 0) { + s->qcow_version = current_version; + error_setg_errno(errp, -ret, "Failed to update the image header"); + return ret; + } + status_cb(bs, 2, 2, cb_opaque); + + 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_UPGRADING, + QCOW2_UPDATING_ENCRYPTION, + 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, + bool force, + Error **errp) +{ + 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, *data_file = NULL; + bool lazy_refcounts = s->use_lazy_refcounts; + bool data_file_raw = data_file_is_raw(bs); + const char *compat = NULL; + int refcount_bits = s->refcount_bits; + int ret; + QemuOptDesc *desc = opts->list->desc; + Qcow2AmendHelperCBInfo helper_cb_info; + bool encryption_update = false; + + 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") || !strcmp(compat, "v2")) { + new_version = 2; + } else if (!strcmp(compat, "1.1") || !strcmp(compat, "v3")) { + new_version = 3; + } else { + error_setg(errp, "Unknown compatibility level %s", compat); + return -EINVAL; + } + } 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 (g_str_has_prefix(desc->name, "encrypt.")) { + if (!s->crypto) { + error_setg(errp, + "Can't amend encryption options - encryption not present"); + return -EINVAL; + } + if (s->crypt_method_header != QCOW_CRYPT_LUKS) { + error_setg(errp, + "Only LUKS encryption options can be amended"); + return -ENOTSUP; + } + encryption_update = true; + } 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_setg(errp, "Refcount width must be a power of two and " + "may not exceed 64 bits"); + return -EINVAL; + } + } else if (!strcmp(desc->name, BLOCK_OPT_DATA_FILE)) { + data_file = qemu_opt_get(opts, BLOCK_OPT_DATA_FILE); + if (data_file && !has_data_file(bs)) { + error_setg(errp, "data-file can only be set for images that " + "use an external data file"); + return -EINVAL; + } + } else if (!strcmp(desc->name, BLOCK_OPT_DATA_FILE_RAW)) { + data_file_raw = qemu_opt_get_bool(opts, BLOCK_OPT_DATA_FILE_RAW, + data_file_raw); + if (data_file_raw && !data_file_is_raw(bs)) { + error_setg(errp, "data-file-raw cannot be set on existing " + "images"); + 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) + + (encryption_update == true) + }; + + /* Upgrade first (some features may require compat=1.1) */ + if (new_version > old_version) { + helper_cb_info.current_operation = QCOW2_UPGRADING; + ret = qcow2_upgrade(bs, new_version, &qcow2_amend_helper_cb, + &helper_cb_info, errp); + if (ret < 0) { + return ret; + } + } + + if (encryption_update) { + QDict *amend_opts_dict; + QCryptoBlockAmendOptions *amend_opts; + + helper_cb_info.current_operation = QCOW2_UPDATING_ENCRYPTION; + amend_opts_dict = qcow2_extract_crypto_opts(opts, "luks", errp); + if (!amend_opts_dict) { + return -EINVAL; + } + amend_opts = block_crypto_amend_opts_init(amend_opts_dict, errp); + qobject_unref(amend_opts_dict); + if (!amend_opts) { + return -EINVAL; + } + ret = qcrypto_block_amend_options(s->crypto, + qcow2_crypto_hdr_read_func, + qcow2_crypto_hdr_write_func, + bs, + amend_opts, + force, + errp); + qapi_free_QCryptoBlockAmendOptions(amend_opts); + if (ret < 0) { + return ret; + } + } + + if (s->refcount_bits != refcount_bits) { + int refcount_order = ctz32(refcount_bits); + + if (new_version < 3 && refcount_bits != 16) { + error_setg(errp, "Refcount widths other 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, errp); + if (ret < 0) { + return ret; + } + } + + /* data-file-raw blocks backing files, so clear it first if requested */ + if (data_file_raw) { + s->autoclear_features |= QCOW2_AUTOCLEAR_DATA_FILE_RAW; + } else { + s->autoclear_features &= ~QCOW2_AUTOCLEAR_DATA_FILE_RAW; + } + + if (data_file) { + g_free(s->image_data_file); + s->image_data_file = *data_file ? g_strdup(data_file) : NULL; + } + + ret = qcow2_update_header(bs); + if (ret < 0) { + error_setg_errno(errp, -ret, "Failed to update the image header"); + return ret; + } + + if (backing_file || backing_format) { + if (g_strcmp0(backing_file, s->image_backing_file) || + g_strcmp0(backing_format, s->image_backing_format)) { + error_setg(errp, "Cannot amend the backing file"); + error_append_hint(errp, + "You can use 'qemu-img rebase' instead.\n"); + return -EINVAL; + } + } + + if (s->use_lazy_refcounts != lazy_refcounts) { + if (lazy_refcounts) { + if (new_version < 3) { + error_setg(errp, "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; + error_setg_errno(errp, -ret, "Failed to update the image header"); + return ret; + } + s->use_lazy_refcounts = true; + } else { + /* make image clean first */ + ret = qcow2_mark_clean(bs); + if (ret < 0) { + error_setg_errno(errp, -ret, "Failed to make the image clean"); + 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; + error_setg_errno(errp, -ret, "Failed to update the image header"); + return ret; + } + s->use_lazy_refcounts = false; + } + } + + if (new_size) { + BlockBackend *blk = blk_new_with_bs(bs, BLK_PERM_RESIZE, BLK_PERM_ALL, + errp); + if (!blk) { + return -EPERM; + } + + /* + * Amending image options should ensure that the image has + * exactly the given new values, so pass exact=true here. + */ + ret = blk_truncate(blk, new_size, true, PREALLOC_MODE_OFF, 0, errp); + blk_unref(blk); + if (ret < 0) { + 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, errp); + if (ret < 0) { + return ret; + } + } + + return 0; +} + +static int coroutine_fn qcow2_co_amend(BlockDriverState *bs, + BlockdevAmendOptions *opts, + bool force, + Error **errp) +{ + BlockdevAmendOptionsQcow2 *qopts = &opts->u.qcow2; + BDRVQcow2State *s = bs->opaque; + int ret = 0; + + if (qopts->has_encrypt) { + if (!s->crypto) { + error_setg(errp, "image is not encrypted, can't amend"); + return -EOPNOTSUPP; + } + + if (qopts->encrypt->format != Q_CRYPTO_BLOCK_FORMAT_LUKS) { + error_setg(errp, + "Amend can't be used to change the qcow2 encryption format"); + return -EOPNOTSUPP; + } + + if (s->crypt_method_header != QCOW_CRYPT_LUKS) { + error_setg(errp, + "Only LUKS encryption options can be amended for qcow2 with blockdev-amend"); + return -EOPNOTSUPP; + } + + ret = qcrypto_block_amend_options(s->crypto, + qcow2_crypto_hdr_read_func, + qcow2_crypto_hdr_write_func, + bs, + qopts->encrypt, + force, + errp); + } + return ret; +} + +/* + * 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 && bdrv_is_writable(bs); + + 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); + g_free(message); + + if (fatal) { + qcow2_mark_corrupt(bs); + bs->drv = NULL; /* make BDS unusable */ + } + + s->signaled_corruption = true; +} + +#define QCOW_COMMON_OPTIONS \ + { \ + .name = BLOCK_OPT_SIZE, \ + .type = QEMU_OPT_SIZE, \ + .help = "Virtual disk size" \ + }, \ + { \ + .name = BLOCK_OPT_COMPAT_LEVEL, \ + .type = QEMU_OPT_STRING, \ + .help = "Compatibility level (v2 [0.10] or v3 [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_DATA_FILE, \ + .type = QEMU_OPT_STRING, \ + .help = "File name of an external data file" \ + }, \ + { \ + .name = BLOCK_OPT_DATA_FILE_RAW, \ + .type = QEMU_OPT_BOOL, \ + .help = "The external data file must stay valid " \ + "as a raw image" \ + }, \ + { \ + .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" \ + } + +static QemuOptsList qcow2_create_opts = { + .name = "qcow2-create-opts", + .head = QTAILQ_HEAD_INITIALIZER(qcow2_create_opts.head), + .desc = { + { \ + .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_EXTL2, \ + .type = QEMU_OPT_BOOL, \ + .help = "Extended L2 tables", \ + .def_value_str = "off" \ + }, \ + { \ + .name = BLOCK_OPT_PREALLOC, \ + .type = QEMU_OPT_STRING, \ + .help = "Preallocation mode (allowed values: off, " \ + "metadata, falloc, full)" \ + }, \ + { \ + .name = BLOCK_OPT_COMPRESSION_TYPE, \ + .type = QEMU_OPT_STRING, \ + .help = "Compression method used for image cluster " \ + "compression", \ + .def_value_str = "zlib" \ + }, + QCOW_COMMON_OPTIONS, + { /* end of list */ } + } +}; + +static QemuOptsList qcow2_amend_opts = { + .name = "qcow2-amend-opts", + .head = QTAILQ_HEAD_INITIALIZER(qcow2_amend_opts.head), + .desc = { + BLOCK_CRYPTO_OPT_DEF_LUKS_STATE("encrypt."), + BLOCK_CRYPTO_OPT_DEF_LUKS_KEYSLOT("encrypt."), + BLOCK_CRYPTO_OPT_DEF_LUKS_OLD_SECRET("encrypt."), + BLOCK_CRYPTO_OPT_DEF_LUKS_NEW_SECRET("encrypt."), + BLOCK_CRYPTO_OPT_DEF_LUKS_ITER_TIME("encrypt."), + QCOW_COMMON_OPTIONS, + { /* end of list */ } + } +}; + +static const char *const qcow2_strong_runtime_opts[] = { + "encrypt." BLOCK_CRYPTO_OPT_QCOW_KEY_SECRET, + + NULL +}; + +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_commit_post = qcow2_reopen_commit_post, + .bdrv_reopen_abort = qcow2_reopen_abort, + .bdrv_join_options = qcow2_join_options, + .bdrv_child_perm = bdrv_default_perms, + .bdrv_co_create_opts = qcow2_co_create_opts, + .bdrv_co_create = qcow2_co_create, + .bdrv_has_zero_init = qcow2_has_zero_init, + .bdrv_co_block_status = qcow2_co_block_status, + + .bdrv_co_preadv_part = qcow2_co_preadv_part, + .bdrv_co_pwritev_part = qcow2_co_pwritev_part, + .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_co_copy_range_from = qcow2_co_copy_range_from, + .bdrv_co_copy_range_to = qcow2_co_copy_range_to, + .bdrv_co_truncate = qcow2_co_truncate, + .bdrv_co_pwritev_compressed_part = qcow2_co_pwritev_compressed_part, + .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_measure = qcow2_measure, + .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, + + .is_format = true, + .supports_backing = true, + .bdrv_change_backing_file = qcow2_change_backing_file, + + .bdrv_refresh_limits = qcow2_refresh_limits, + .bdrv_co_invalidate_cache = qcow2_co_invalidate_cache, + .bdrv_inactivate = qcow2_inactivate, + + .create_opts = &qcow2_create_opts, + .amend_opts = &qcow2_amend_opts, + .strong_runtime_opts = qcow2_strong_runtime_opts, + .mutable_opts = mutable_opts, + .bdrv_co_check = qcow2_co_check, + .bdrv_amend_options = qcow2_amend_options, + .bdrv_co_amend = qcow2_co_amend, + + .bdrv_detach_aio_context = qcow2_detach_aio_context, + .bdrv_attach_aio_context = qcow2_attach_aio_context, + + .bdrv_supports_persistent_dirty_bitmap = + qcow2_supports_persistent_dirty_bitmap, + .bdrv_co_can_store_new_dirty_bitmap = qcow2_co_can_store_new_dirty_bitmap, + .bdrv_co_remove_persistent_dirty_bitmap = + qcow2_co_remove_persistent_dirty_bitmap, +}; + +static void bdrv_qcow2_init(void) +{ + bdrv_register(&bdrv_qcow2); +} + +block_init(bdrv_qcow2_init); |