diff options
Diffstat (limited to 'contrib/qemu/block/qcow2.c')
| -rw-r--r-- | contrib/qemu/block/qcow2.c | 1825 |
1 files changed, 1825 insertions, 0 deletions
diff --git a/contrib/qemu/block/qcow2.c b/contrib/qemu/block/qcow2.c new file mode 100644 index 00000000000..0eceefe2cd9 --- /dev/null +++ b/contrib/qemu/block/qcow2.c @@ -0,0 +1,1825 @@ +/* + * Block driver for the QCOW version 2 format + * + * Copyright (c) 2004-2006 Fabrice Bellard + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ +#include "qemu-common.h" +#include "block/block_int.h" +#include "qemu/module.h" +#include <zlib.h> +#include "qemu/aes.h" +#include "block/qcow2.h" +#include "qemu/error-report.h" +#include "qapi/qmp/qerror.h" +#include "qapi/qmp/qbool.h" +#include "trace.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; +} QCowExtension; + +#define QCOW2_EXT_MAGIC_END 0 +#define QCOW2_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA +#define QCOW2_EXT_MAGIC_FEATURE_TABLE 0x6803f857 + +static int qcow2_probe(const uint8_t *buf, int buf_size, const char *filename) +{ + const QCowHeader *cow_header = (const void *)buf; + + if (buf_size >= sizeof(QCowHeader) && + be32_to_cpu(cow_header->magic) == QCOW_MAGIC && + be32_to_cpu(cow_header->version) >= 2) + return 100; + else + return 0; +} + + +/* + * read qcow2 extension and fill bs + * start reading from start_offset + * finish reading upon magic of value 0 or when end_offset reached + * unknown magic is skipped (future extension this version knows nothing about) + * return 0 upon success, non-0 otherwise + */ +static int qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset, + uint64_t end_offset, void **p_feature_table) +{ + BDRVQcowState *s = bs->opaque; + QCowExtension ext; + uint64_t offset; + int ret; + +#ifdef DEBUG_EXT + printf("qcow2_read_extensions: start=%ld end=%ld\n", start_offset, end_offset); +#endif + offset = start_offset; + while (offset < end_offset) { + +#ifdef DEBUG_EXT + /* Sanity check */ + if (offset > s->cluster_size) + printf("qcow2_read_extension: suspicious offset %lu\n", offset); + + printf("attempting to read extended header in offset %lu\n", offset); +#endif + + if (bdrv_pread(bs->file, offset, &ext, sizeof(ext)) != sizeof(ext)) { + fprintf(stderr, "qcow2_read_extension: ERROR: " + "pread fail from offset %" PRIu64 "\n", + offset); + return 1; + } + be32_to_cpus(&ext.magic); + be32_to_cpus(&ext.len); + offset += sizeof(ext); +#ifdef DEBUG_EXT + printf("ext.magic = 0x%x\n", ext.magic); +#endif + if (ext.len > end_offset - offset) { + error_report("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)) { + fprintf(stderr, "ERROR: ext_backing_format: len=%u too large" + " (>=%zu)\n", + ext.len, sizeof(bs->backing_format)); + return 2; + } + if (bdrv_pread(bs->file, offset , bs->backing_format, + ext.len) != ext.len) + return 3; + bs->backing_format[ext.len] = '\0'; +#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) { + return ret; + } + + *p_feature_table = feature_table; + } + break; + + default: + /* unknown magic - save it in case we need to rewrite the header */ + { + Qcow2UnknownHeaderExtension *uext; + + uext = g_malloc0(sizeof(*uext) + ext.len); + uext->magic = ext.magic; + uext->len = ext.len; + QLIST_INSERT_HEAD(&s->unknown_header_ext, uext, next); + + ret = bdrv_pread(bs->file, offset , uext->data, uext->len); + if (ret < 0) { + return ret; + } + } + break; + } + + offset += ((ext.len + 7) & ~7); + } + + return 0; +} + +static void cleanup_unknown_header_ext(BlockDriverState *bs) +{ + BDRVQcowState *s = bs->opaque; + Qcow2UnknownHeaderExtension *uext, *next; + + QLIST_FOREACH_SAFE(uext, &s->unknown_header_ext, next, next) { + QLIST_REMOVE(uext, next); + g_free(uext); + } +} + +static void GCC_FMT_ATTR(2, 3) report_unsupported(BlockDriverState *bs, + const char *fmt, ...) +{ + char msg[64]; + va_list ap; + + va_start(ap, fmt); + vsnprintf(msg, sizeof(msg), fmt, ap); + va_end(ap); + + qerror_report(QERR_UNKNOWN_BLOCK_FORMAT_FEATURE, + bs->device_name, "qcow2", msg); +} + +static void report_unsupported_feature(BlockDriverState *bs, + Qcow2Feature *table, uint64_t mask) +{ + while (table && table->name[0] != '\0') { + if (table->type == QCOW2_FEAT_TYPE_INCOMPATIBLE) { + if (mask & (1 << table->bit)) { + report_unsupported(bs, "%.46s",table->name); + mask &= ~(1 << table->bit); + } + } + table++; + } + + if (mask) { + report_unsupported(bs, "Unknown incompatible feature: %" PRIx64, mask); + } +} + +/* + * 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) +{ + BDRVQcowState *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); + 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) +{ + BDRVQcowState *s = bs->opaque; + + if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { + int ret = bdrv_flush(bs); + if (ret < 0) { + return ret; + } + + s->incompatible_features &= ~QCOW2_INCOMPAT_DIRTY; + return qcow2_update_header(bs); + } + return 0; +} + +static int qcow2_check(BlockDriverState *bs, BdrvCheckResult *result, + BdrvCheckMode fix) +{ + int ret = qcow2_check_refcounts(bs, result, fix); + if (ret < 0) { + return ret; + } + + if (fix && result->check_errors == 0 && result->corruptions == 0) { + return qcow2_mark_clean(bs); + } + return ret; +} + +static QemuOptsList qcow2_runtime_opts = { + .name = "qcow2", + .head = QTAILQ_HEAD_INITIALIZER(qcow2_runtime_opts.head), + .desc = { + { + .name = "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", + }, + { /* end of list */ } + }, +}; + +static int qcow2_open(BlockDriverState *bs, QDict *options, int flags) +{ + BDRVQcowState *s = bs->opaque; + int len, i, ret = 0; + QCowHeader header; + QemuOpts *opts; + Error *local_err = NULL; + uint64_t ext_end; + uint64_t l1_vm_state_index; + + ret = bdrv_pread(bs->file, 0, &header, sizeof(header)); + if (ret < 0) { + goto fail; + } + be32_to_cpus(&header.magic); + be32_to_cpus(&header.version); + be64_to_cpus(&header.backing_file_offset); + be32_to_cpus(&header.backing_file_size); + be64_to_cpus(&header.size); + be32_to_cpus(&header.cluster_bits); + be32_to_cpus(&header.crypt_method); + be64_to_cpus(&header.l1_table_offset); + be32_to_cpus(&header.l1_size); + be64_to_cpus(&header.refcount_table_offset); + be32_to_cpus(&header.refcount_table_clusters); + be64_to_cpus(&header.snapshots_offset); + be32_to_cpus(&header.nb_snapshots); + + if (header.magic != QCOW_MAGIC) { + ret = -EMEDIUMTYPE; + goto fail; + } + if (header.version < 2 || header.version > 3) { + report_unsupported(bs, "QCOW version %d", header.version); + ret = -ENOTSUP; + goto fail; + } + + s->qcow_version = header.version; + + /* Initialise version 3 header fields */ + if (header.version == 2) { + header.incompatible_features = 0; + header.compatible_features = 0; + header.autoclear_features = 0; + header.refcount_order = 4; + header.header_length = 72; + } else { + be64_to_cpus(&header.incompatible_features); + be64_to_cpus(&header.compatible_features); + be64_to_cpus(&header.autoclear_features); + be32_to_cpus(&header.refcount_order); + be32_to_cpus(&header.header_length); + } + + if (header.header_length > 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) { + goto fail; + } + } + + if (header.backing_file_offset) { + ext_end = header.backing_file_offset; + } else { + ext_end = 1 << header.cluster_bits; + } + + /* Handle feature bits */ + s->incompatible_features = header.incompatible_features; + s->compatible_features = header.compatible_features; + s->autoclear_features = header.autoclear_features; + + if (s->incompatible_features & ~QCOW2_INCOMPAT_MASK) { + void *feature_table = NULL; + qcow2_read_extensions(bs, header.header_length, ext_end, + &feature_table); + report_unsupported_feature(bs, feature_table, + s->incompatible_features & + ~QCOW2_INCOMPAT_MASK); + ret = -ENOTSUP; + goto fail; + } + + /* Check support for various header values */ + if (header.refcount_order != 4) { + report_unsupported(bs, "%d bit reference counts", + 1 << header.refcount_order); + ret = -ENOTSUP; + goto fail; + } + + if (header.cluster_bits < MIN_CLUSTER_BITS || + header.cluster_bits > MAX_CLUSTER_BITS) { + ret = -EINVAL; + goto fail; + } + if (header.crypt_method > QCOW_CRYPT_AES) { + ret = -EINVAL; + goto fail; + } + s->crypt_method_header = header.crypt_method; + if (s->crypt_method_header) { + bs->encrypted = 1; + } + s->cluster_bits = header.cluster_bits; + s->cluster_size = 1 << s->cluster_bits; + s->cluster_sectors = 1 << (s->cluster_bits - 9); + s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */ + s->l2_size = 1 << s->l2_bits; + bs->total_sectors = header.size / 512; + s->csize_shift = (62 - (s->cluster_bits - 8)); + s->csize_mask = (1 << (s->cluster_bits - 8)) - 1; + s->cluster_offset_mask = (1LL << s->csize_shift) - 1; + s->refcount_table_offset = header.refcount_table_offset; + s->refcount_table_size = + header.refcount_table_clusters << (s->cluster_bits - 3); + + s->snapshots_offset = header.snapshots_offset; + s->nb_snapshots = header.nb_snapshots; + + /* read the level 1 table */ + s->l1_size = header.l1_size; + + l1_vm_state_index = size_to_l1(s, header.size); + if (l1_vm_state_index > INT_MAX) { + 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) { + ret = -EINVAL; + goto fail; + } + s->l1_table_offset = header.l1_table_offset; + if (s->l1_size > 0) { + s->l1_table = g_malloc0( + align_offset(s->l1_size * sizeof(uint64_t), 512)); + ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table, + s->l1_size * sizeof(uint64_t)); + if (ret < 0) { + goto fail; + } + for(i = 0;i < s->l1_size; i++) { + be64_to_cpus(&s->l1_table[i]); + } + } + + /* alloc L2 table/refcount block cache */ + s->l2_table_cache = qcow2_cache_create(bs, L2_CACHE_SIZE); + s->refcount_block_cache = qcow2_cache_create(bs, REFCOUNT_CACHE_SIZE); + + s->cluster_cache = g_malloc(s->cluster_size); + /* one more sector for decompressed data alignment */ + s->cluster_data = qemu_blockalign(bs, QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size + + 512); + s->cluster_cache_offset = -1; + s->flags = flags; + + ret = qcow2_refcount_init(bs); + if (ret != 0) { + 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)) { + ret = -EINVAL; + goto fail; + } + + /* read the backing file name */ + if (header.backing_file_offset != 0) { + len = header.backing_file_size; + if (len > 1023) { + len = 1023; + } + ret = bdrv_pread(bs->file, header.backing_file_offset, + bs->backing_file, len); + if (ret < 0) { + goto fail; + } + bs->backing_file[len] = '\0'; + } + + ret = qcow2_read_snapshots(bs); + if (ret < 0) { + goto fail; + } + + /* Clear unknown autoclear feature bits */ + if (!bs->read_only && s->autoclear_features != 0) { + s->autoclear_features = 0; + ret = qcow2_update_header(bs); + if (ret < 0) { + goto fail; + } + } + + /* Initialise locks */ + qemu_co_mutex_init(&s->lock); + + /* Repair image if dirty */ + if (!(flags & BDRV_O_CHECK) && !bs->read_only && + (s->incompatible_features & QCOW2_INCOMPAT_DIRTY)) { + BdrvCheckResult result = {0}; + + ret = qcow2_check(bs, &result, BDRV_FIX_ERRORS); + if (ret < 0) { + goto fail; + } + } + + /* Enable lazy_refcounts according to image and command line options */ + opts = qemu_opts_create_nofail(&qcow2_runtime_opts); + qemu_opts_absorb_qdict(opts, options, &local_err); + if (error_is_set(&local_err)) { + qerror_report_err(local_err); + error_free(local_err); + ret = -EINVAL; + goto fail; + } + + s->use_lazy_refcounts = qemu_opt_get_bool(opts, QCOW2_OPT_LAZY_REFCOUNTS, + (s->compatible_features & QCOW2_COMPAT_LAZY_REFCOUNTS)); + + s->discard_passthrough[QCOW2_DISCARD_NEVER] = false; + s->discard_passthrough[QCOW2_DISCARD_ALWAYS] = true; + s->discard_passthrough[QCOW2_DISCARD_REQUEST] = + qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_REQUEST, + flags & BDRV_O_UNMAP); + s->discard_passthrough[QCOW2_DISCARD_SNAPSHOT] = + qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_SNAPSHOT, true); + s->discard_passthrough[QCOW2_DISCARD_OTHER] = + qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_OTHER, false); + + qemu_opts_del(opts); + + if (s->use_lazy_refcounts && s->qcow_version < 3) { + qerror_report(ERROR_CLASS_GENERIC_ERROR, "Lazy refcounts require " + "a qcow2 image with at least qemu 1.1 compatibility level"); + ret = -EINVAL; + goto fail; + } + +#ifdef DEBUG_ALLOC + { + BdrvCheckResult result = {0}; + qcow2_check_refcounts(bs, &result, 0); + } +#endif + return ret; + + fail: + g_free(s->unknown_header_fields); + cleanup_unknown_header_ext(bs); + qcow2_free_snapshots(bs); + qcow2_refcount_close(bs); + g_free(s->l1_table); + if (s->l2_table_cache) { + qcow2_cache_destroy(bs, s->l2_table_cache); + } + g_free(s->cluster_cache); + qemu_vfree(s->cluster_data); + return ret; +} + +static int qcow2_set_key(BlockDriverState *bs, const char *key) +{ + BDRVQcowState *s = bs->opaque; + uint8_t keybuf[16]; + int len, i; + + memset(keybuf, 0, 16); + len = strlen(key); + if (len > 16) + len = 16; + /* XXX: we could compress the chars to 7 bits to increase + entropy */ + for(i = 0;i < len;i++) { + keybuf[i] = key[i]; + } + s->crypt_method = s->crypt_method_header; + + if (AES_set_encrypt_key(keybuf, 128, &s->aes_encrypt_key) != 0) + return -1; + if (AES_set_decrypt_key(keybuf, 128, &s->aes_decrypt_key) != 0) + return -1; +#if 0 + /* test */ + { + uint8_t in[16]; + uint8_t out[16]; + uint8_t tmp[16]; + for(i=0;i<16;i++) + in[i] = i; + AES_encrypt(in, tmp, &s->aes_encrypt_key); + AES_decrypt(tmp, out, &s->aes_decrypt_key); + for(i = 0; i < 16; i++) + printf(" %02x", tmp[i]); + printf("\n"); + for(i = 0; i < 16; i++) + printf(" %02x", out[i]); + printf("\n"); + } +#endif + return 0; +} + +/* We have nothing to do for QCOW2 reopen, stubs just return + * success */ +static int qcow2_reopen_prepare(BDRVReopenState *state, + BlockReopenQueue *queue, Error **errp) +{ + return 0; +} + +static int coroutine_fn qcow2_co_is_allocated(BlockDriverState *bs, + int64_t sector_num, int nb_sectors, int *pnum) +{ + BDRVQcowState *s = bs->opaque; + uint64_t cluster_offset; + int ret; + + *pnum = nb_sectors; + /* FIXME We can get errors here, but the bdrv_co_is_allocated interface + * can't pass them on today */ + qemu_co_mutex_lock(&s->lock); + ret = qcow2_get_cluster_offset(bs, sector_num << 9, pnum, &cluster_offset); + qemu_co_mutex_unlock(&s->lock); + if (ret < 0) { + *pnum = 0; + } + + return (cluster_offset != 0) || (ret == QCOW2_CLUSTER_ZERO); +} + +/* handle reading after the end of the backing file */ +int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov, + int64_t sector_num, int nb_sectors) +{ + int n1; + if ((sector_num + nb_sectors) <= bs->total_sectors) + return nb_sectors; + if (sector_num >= bs->total_sectors) + n1 = 0; + else + n1 = bs->total_sectors - sector_num; + + qemu_iovec_memset(qiov, 512 * n1, 0, 512 * (nb_sectors - n1)); + + return n1; +} + +static coroutine_fn int qcow2_co_readv(BlockDriverState *bs, int64_t sector_num, + int remaining_sectors, QEMUIOVector *qiov) +{ + BDRVQcowState *s = bs->opaque; + int index_in_cluster, n1; + int ret; + int cur_nr_sectors; /* number of sectors in current iteration */ + uint64_t cluster_offset = 0; + uint64_t bytes_done = 0; + QEMUIOVector hd_qiov; + uint8_t *cluster_data = NULL; + + qemu_iovec_init(&hd_qiov, qiov->niov); + + qemu_co_mutex_lock(&s->lock); + + while (remaining_sectors != 0) { + + /* prepare next request */ + cur_nr_sectors = remaining_sectors; + if (s->crypt_method) { + cur_nr_sectors = MIN(cur_nr_sectors, + QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors); + } + + ret = qcow2_get_cluster_offset(bs, sector_num << 9, + &cur_nr_sectors, &cluster_offset); + if (ret < 0) { + goto fail; + } + + index_in_cluster = sector_num & (s->cluster_sectors - 1); + + qemu_iovec_reset(&hd_qiov); + qemu_iovec_concat(&hd_qiov, qiov, bytes_done, + cur_nr_sectors * 512); + + switch (ret) { + case QCOW2_CLUSTER_UNALLOCATED: + + if (bs->backing_hd) { + /* read from the base image */ + n1 = qcow2_backing_read1(bs->backing_hd, &hd_qiov, + sector_num, cur_nr_sectors); + if (n1 > 0) { + BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO); + qemu_co_mutex_unlock(&s->lock); + ret = bdrv_co_readv(bs->backing_hd, sector_num, + n1, &hd_qiov); + qemu_co_mutex_lock(&s->lock); + if (ret < 0) { + goto fail; + } + } + } else { + /* Note: in this case, no need to wait */ + qemu_iovec_memset(&hd_qiov, 0, 0, 512 * cur_nr_sectors); + } + break; + + case QCOW2_CLUSTER_ZERO: + qemu_iovec_memset(&hd_qiov, 0, 0, 512 * cur_nr_sectors); + break; + + case QCOW2_CLUSTER_COMPRESSED: + /* add AIO support for compressed blocks ? */ + ret = qcow2_decompress_cluster(bs, cluster_offset); + if (ret < 0) { + goto fail; + } + + qemu_iovec_from_buf(&hd_qiov, 0, + s->cluster_cache + index_in_cluster * 512, + 512 * cur_nr_sectors); + break; + + case QCOW2_CLUSTER_NORMAL: + if ((cluster_offset & 511) != 0) { + ret = -EIO; + goto fail; + } + + if (s->crypt_method) { + /* + * For encrypted images, read everything into a temporary + * contiguous buffer on which the AES functions can work. + */ + if (!cluster_data) { + cluster_data = + qemu_blockalign(bs, QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); + } + + assert(cur_nr_sectors <= + QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors); + qemu_iovec_reset(&hd_qiov); + qemu_iovec_add(&hd_qiov, cluster_data, + 512 * cur_nr_sectors); + } + + BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); + qemu_co_mutex_unlock(&s->lock); + ret = bdrv_co_readv(bs->file, + (cluster_offset >> 9) + index_in_cluster, + cur_nr_sectors, &hd_qiov); + qemu_co_mutex_lock(&s->lock); + if (ret < 0) { + goto fail; + } + if (s->crypt_method) { + qcow2_encrypt_sectors(s, sector_num, cluster_data, + cluster_data, cur_nr_sectors, 0, &s->aes_decrypt_key); + qemu_iovec_from_buf(qiov, bytes_done, + cluster_data, 512 * cur_nr_sectors); + } + break; + + default: + g_assert_not_reached(); + ret = -EIO; + goto fail; + } + + remaining_sectors -= cur_nr_sectors; + sector_num += cur_nr_sectors; + bytes_done += cur_nr_sectors * 512; + } + ret = 0; + +fail: + qemu_co_mutex_unlock(&s->lock); + + qemu_iovec_destroy(&hd_qiov); + qemu_vfree(cluster_data); + + return ret; +} + +static coroutine_fn int qcow2_co_writev(BlockDriverState *bs, + int64_t sector_num, + int remaining_sectors, + QEMUIOVector *qiov) +{ + BDRVQcowState *s = bs->opaque; + int index_in_cluster; + int n_end; + int ret; + int cur_nr_sectors; /* number of sectors in current iteration */ + uint64_t cluster_offset; + QEMUIOVector hd_qiov; + uint64_t bytes_done = 0; + uint8_t *cluster_data = NULL; + QCowL2Meta *l2meta = NULL; + + trace_qcow2_writev_start_req(qemu_coroutine_self(), sector_num, + remaining_sectors); + + qemu_iovec_init(&hd_qiov, qiov->niov); + + s->cluster_cache_offset = -1; /* disable compressed cache */ + + qemu_co_mutex_lock(&s->lock); + + while (remaining_sectors != 0) { + + l2meta = NULL; + + trace_qcow2_writev_start_part(qemu_coroutine_self()); + index_in_cluster = sector_num & (s->cluster_sectors - 1); + n_end = index_in_cluster + remaining_sectors; + if (s->crypt_method && + n_end > QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors) { + n_end = QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors; + } + + ret = qcow2_alloc_cluster_offset(bs, sector_num << 9, + index_in_cluster, n_end, &cur_nr_sectors, &cluster_offset, &l2meta); + if (ret < 0) { + goto fail; + } + + assert((cluster_offset & 511) == 0); + + qemu_iovec_reset(&hd_qiov); + qemu_iovec_concat(&hd_qiov, qiov, bytes_done, + cur_nr_sectors * 512); + + if (s->crypt_method) { + if (!cluster_data) { + cluster_data = qemu_blockalign(bs, QCOW_MAX_CRYPT_CLUSTERS * + s->cluster_size); + } + + assert(hd_qiov.size <= + QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); + qemu_iovec_to_buf(&hd_qiov, 0, cluster_data, hd_qiov.size); + + qcow2_encrypt_sectors(s, sector_num, cluster_data, + cluster_data, cur_nr_sectors, 1, &s->aes_encrypt_key); + + qemu_iovec_reset(&hd_qiov); + qemu_iovec_add(&hd_qiov, cluster_data, + cur_nr_sectors * 512); + } + + qemu_co_mutex_unlock(&s->lock); + BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); + trace_qcow2_writev_data(qemu_coroutine_self(), + (cluster_offset >> 9) + index_in_cluster); + ret = bdrv_co_writev(bs->file, + (cluster_offset >> 9) + index_in_cluster, + cur_nr_sectors, &hd_qiov); + qemu_co_mutex_lock(&s->lock); + if (ret < 0) { + goto fail; + } + + while (l2meta != NULL) { + QCowL2Meta *next; + + ret = qcow2_alloc_cluster_link_l2(bs, l2meta); + if (ret < 0) { + goto fail; + } + + /* Take the request off the list of running requests */ + if (l2meta->nb_clusters != 0) { + QLIST_REMOVE(l2meta, next_in_flight); + } + + qemu_co_queue_restart_all(&l2meta->dependent_requests); + + next = l2meta->next; + g_free(l2meta); + l2meta = next; + } + + remaining_sectors -= cur_nr_sectors; + sector_num += cur_nr_sectors; + bytes_done += cur_nr_sectors * 512; + trace_qcow2_writev_done_part(qemu_coroutine_self(), cur_nr_sectors); + } + ret = 0; + +fail: + qemu_co_mutex_unlock(&s->lock); + + while (l2meta != NULL) { + QCowL2Meta *next; + + if (l2meta->nb_clusters != 0) { + QLIST_REMOVE(l2meta, next_in_flight); + } + qemu_co_queue_restart_all(&l2meta->dependent_requests); + + next = l2meta->next; + g_free(l2meta); + l2meta = next; + } + + qemu_iovec_destroy(&hd_qiov); + qemu_vfree(cluster_data); + trace_qcow2_writev_done_req(qemu_coroutine_self(), ret); + + return ret; +} + +static void qcow2_close(BlockDriverState *bs) +{ + BDRVQcowState *s = bs->opaque; + g_free(s->l1_table); + + qcow2_cache_flush(bs, s->l2_table_cache); + qcow2_cache_flush(bs, s->refcount_block_cache); + + qcow2_mark_clean(bs); + + qcow2_cache_destroy(bs, s->l2_table_cache); + qcow2_cache_destroy(bs, s->refcount_block_cache); + + g_free(s->unknown_header_fields); + cleanup_unknown_header_ext(bs); + + g_free(s->cluster_cache); + qemu_vfree(s->cluster_data); + qcow2_refcount_close(bs); + qcow2_free_snapshots(bs); +} + +static void qcow2_invalidate_cache(BlockDriverState *bs) +{ + BDRVQcowState *s = bs->opaque; + int flags = s->flags; + AES_KEY aes_encrypt_key; + AES_KEY aes_decrypt_key; + uint32_t crypt_method = 0; + QDict *options; + + /* + * Backing files are read-only which makes all of their metadata immutable, + * that means we don't have to worry about reopening them here. + */ + + if (s->crypt_method) { + crypt_method = s->crypt_method; + memcpy(&aes_encrypt_key, &s->aes_encrypt_key, sizeof(aes_encrypt_key)); + memcpy(&aes_decrypt_key, &s->aes_decrypt_key, sizeof(aes_decrypt_key)); + } + + qcow2_close(bs); + + options = qdict_new(); + qdict_put(options, QCOW2_OPT_LAZY_REFCOUNTS, + qbool_from_int(s->use_lazy_refcounts)); + + memset(s, 0, sizeof(BDRVQcowState)); + qcow2_open(bs, options, flags); + + QDECREF(options); + + if (crypt_method) { + s->crypt_method = crypt_method; + memcpy(&s->aes_encrypt_key, &aes_encrypt_key, sizeof(aes_encrypt_key)); + memcpy(&s->aes_decrypt_key, &aes_decrypt_key, sizeof(aes_decrypt_key)); + } +} + +static size_t header_ext_add(char *buf, uint32_t magic, const void *s, + size_t len, size_t buflen) +{ + QCowExtension *ext_backing_fmt = (QCowExtension*) buf; + size_t ext_len = sizeof(QCowExtension) + ((len + 7) & ~7); + + if (buflen < ext_len) { + return -ENOSPC; + } + + *ext_backing_fmt = (QCowExtension) { + .magic = cpu_to_be32(magic), + .len = cpu_to_be32(len), + }; + memcpy(buf + sizeof(QCowExtension), s, len); + + return ext_len; +} + +/* + * Updates the qcow2 header, including the variable length parts of it, i.e. + * the backing file name and all extensions. qcow2 was not designed to allow + * such changes, so if we run out of space (we can only use the first cluster) + * this function may fail. + * + * Returns 0 on success, -errno in error cases. + */ +int qcow2_update_header(BlockDriverState *bs) +{ + BDRVQcowState *s = bs->opaque; + QCowHeader *header; + char *buf; + size_t buflen = s->cluster_size; + int ret; + uint64_t total_size; + uint32_t refcount_table_clusters; + size_t header_length; + Qcow2UnknownHeaderExtension *uext; + + buf = qemu_blockalign(bs, buflen); + + /* Header structure */ + header = (QCowHeader*) buf; + + if (buflen < sizeof(*header)) { + ret = -ENOSPC; + goto fail; + } + + header_length = sizeof(*header) + s->unknown_header_fields_size; + total_size = bs->total_sectors * BDRV_SECTOR_SIZE; + refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3); + + *header = (QCowHeader) { + /* Version 2 fields */ + .magic = cpu_to_be32(QCOW_MAGIC), + .version = cpu_to_be32(s->qcow_version), + .backing_file_offset = 0, + .backing_file_size = 0, + .cluster_bits = cpu_to_be32(s->cluster_bits), + .size = cpu_to_be64(total_size), + .crypt_method = cpu_to_be32(s->crypt_method_header), + .l1_size = cpu_to_be32(s->l1_size), + .l1_table_offset = cpu_to_be64(s->l1_table_offset), + .refcount_table_offset = cpu_to_be64(s->refcount_table_offset), + .refcount_table_clusters = cpu_to_be32(refcount_table_clusters), + .nb_snapshots = cpu_to_be32(s->nb_snapshots), + .snapshots_offset = cpu_to_be64(s->snapshots_offset), + + /* Version 3 fields */ + .incompatible_features = cpu_to_be64(s->incompatible_features), + .compatible_features = cpu_to_be64(s->compatible_features), + .autoclear_features = cpu_to_be64(s->autoclear_features), + .refcount_order = cpu_to_be32(3 + REFCOUNT_SHIFT), + .header_length = cpu_to_be32(header_length), + }; + + /* For older versions, write a shorter header */ + switch (s->qcow_version) { + case 2: + ret = offsetof(QCowHeader, incompatible_features); + break; + case 3: + ret = sizeof(*header); + break; + default: + ret = -EINVAL; + goto fail; + } + + buf += ret; + buflen -= ret; + memset(buf, 0, buflen); + + /* Preserve any unknown field in the header */ + if (s->unknown_header_fields_size) { + if (buflen < s->unknown_header_fields_size) { + ret = -ENOSPC; + goto fail; + } + + memcpy(buf, s->unknown_header_fields, s->unknown_header_fields_size); + buf += s->unknown_header_fields_size; + buflen -= s->unknown_header_fields_size; + } + + /* Backing file format header extension */ + if (*bs->backing_format) { + ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BACKING_FORMAT, + bs->backing_format, strlen(bs->backing_format), + buflen); + if (ret < 0) { + goto fail; + } + + buf += ret; + buflen -= ret; + } + + /* Feature table */ + Qcow2Feature features[] = { + { + .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, + .bit = QCOW2_INCOMPAT_DIRTY_BITNR, + .name = "dirty bit", + }, + { + .type = QCOW2_FEAT_TYPE_COMPATIBLE, + .bit = QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR, + .name = "lazy refcounts", + }, + }; + + ret = header_ext_add(buf, QCOW2_EXT_MAGIC_FEATURE_TABLE, + features, sizeof(features), buflen); + if (ret < 0) { + goto fail; + } + buf += ret; + buflen -= ret; + + /* Keep unknown header extensions */ + QLIST_FOREACH(uext, &s->unknown_header_ext, next) { + ret = header_ext_add(buf, uext->magic, uext->data, uext->len, buflen); + if (ret < 0) { + goto fail; + } + + buf += ret; + buflen -= ret; + } + + /* End of header extensions */ + ret = header_ext_add(buf, QCOW2_EXT_MAGIC_END, NULL, 0, buflen); + if (ret < 0) { + goto fail; + } + + buf += ret; + buflen -= ret; + + /* Backing file name */ + if (*bs->backing_file) { + size_t backing_file_len = strlen(bs->backing_file); + + if (buflen < backing_file_len) { + ret = -ENOSPC; + goto fail; + } + + /* Using strncpy is ok here, since buf is not NUL-terminated. */ + strncpy(buf, bs->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) +{ + pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: ""); + pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: ""); + + return qcow2_update_header(bs); +} + +static int preallocate(BlockDriverState *bs) +{ + uint64_t nb_sectors; + uint64_t offset; + uint64_t host_offset = 0; + int num; + int ret; + QCowL2Meta *meta; + + nb_sectors = bdrv_getlength(bs) >> 9; + offset = 0; + + while (nb_sectors) { + num = MIN(nb_sectors, INT_MAX >> 9); + ret = qcow2_alloc_cluster_offset(bs, offset, 0, num, &num, + &host_offset, &meta); + if (ret < 0) { + return ret; + } + + ret = qcow2_alloc_cluster_link_l2(bs, meta); + if (ret < 0) { + qcow2_free_any_clusters(bs, meta->alloc_offset, meta->nb_clusters, + QCOW2_DISCARD_NEVER); + return ret; + } + + /* There are no dependent requests, but we need to remove our request + * from the list of in-flight requests */ + if (meta != NULL) { + QLIST_REMOVE(meta, next_in_flight); + } + + /* TODO Preallocate data if requested */ + + nb_sectors -= num; + offset += num << 9; + } + + /* + * It is expected that the image file is large enough to actually contain + * all of the allocated clusters (otherwise we get failing reads after + * EOF). Extend the image to the last allocated sector. + */ + if (host_offset != 0) { + uint8_t buf[512]; + memset(buf, 0, 512); + ret = bdrv_write(bs->file, (host_offset >> 9) + num - 1, buf, 1); + if (ret < 0) { + return ret; + } + } + + return 0; +} + +static int qcow2_create2(const char *filename, int64_t total_size, + const char *backing_file, const char *backing_format, + int flags, size_t cluster_size, int prealloc, + QEMUOptionParameter *options, int version) +{ + /* Calculate cluster_bits */ + int cluster_bits; + cluster_bits = ffs(cluster_size) - 1; + if (cluster_bits < MIN_CLUSTER_BITS || cluster_bits > MAX_CLUSTER_BITS || + (1 << cluster_bits) != cluster_size) + { + error_report( + "Cluster size must be a power of two between %d and %dk", + 1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10)); + return -EINVAL; + } + + /* + * Open the image file and write a minimal qcow2 header. + * + * We keep things simple and start with a zero-sized image. We also + * do without refcount blocks or a L1 table for now. We'll fix the + * inconsistency later. + * + * We do need a refcount table because growing the refcount table means + * allocating two new refcount blocks - the seconds of which would be at + * 2 GB for 64k clusters, and we don't want to have a 2 GB initial file + * size for any qcow2 image. + */ + BlockDriverState* bs; + QCowHeader header; + uint8_t* refcount_table; + int ret; + + ret = bdrv_create_file(filename, options); + if (ret < 0) { + return ret; + } + + ret = bdrv_file_open(&bs, filename, NULL, BDRV_O_RDWR); + if (ret < 0) { + return ret; + } + + /* Write the header */ + memset(&header, 0, sizeof(header)); + header.magic = cpu_to_be32(QCOW_MAGIC); + header.version = cpu_to_be32(version); + header.cluster_bits = cpu_to_be32(cluster_bits); + header.size = cpu_to_be64(0); + header.l1_table_offset = cpu_to_be64(0); + header.l1_size = cpu_to_be32(0); + header.refcount_table_offset = cpu_to_be64(cluster_size); + header.refcount_table_clusters = cpu_to_be32(1); + header.refcount_order = cpu_to_be32(3 + REFCOUNT_SHIFT); + header.header_length = cpu_to_be32(sizeof(header)); + + if (flags & BLOCK_FLAG_ENCRYPT) { + header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES); + } else { + header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); + } + + if (flags & BLOCK_FLAG_LAZY_REFCOUNTS) { + header.compatible_features |= + cpu_to_be64(QCOW2_COMPAT_LAZY_REFCOUNTS); + } + + ret = bdrv_pwrite(bs, 0, &header, sizeof(header)); + if (ret < 0) { + goto out; + } + + /* Write an empty refcount table */ + refcount_table = g_malloc0(cluster_size); + ret = bdrv_pwrite(bs, cluster_size, refcount_table, cluster_size); + g_free(refcount_table); + + if (ret < 0) { + goto out; + } + + bdrv_close(bs); + + /* + * 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) + */ + BlockDriver* drv = bdrv_find_format("qcow2"); + assert(drv != NULL); + ret = bdrv_open(bs, filename, NULL, + BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_NO_FLUSH, drv); + if (ret < 0) { + goto out; + } + + ret = qcow2_alloc_clusters(bs, 2 * cluster_size); + if (ret < 0) { + goto out; + + } else if (ret != 0) { + error_report("Huh, first cluster in empty image is already in use?"); + abort(); + } + + /* Okay, now that we have a valid image, let's give it the right size */ + ret = bdrv_truncate(bs, total_size * BDRV_SECTOR_SIZE); + if (ret < 0) { + goto out; + } + + /* Want a backing file? There you go.*/ + if (backing_file) { + ret = bdrv_change_backing_file(bs, backing_file, backing_format); + if (ret < 0) { + goto out; + } + } + + /* And if we're supposed to preallocate metadata, do that now */ + if (prealloc) { + BDRVQcowState *s = bs->opaque; + qemu_co_mutex_lock(&s->lock); + ret = preallocate(bs); + qemu_co_mutex_unlock(&s->lock); + if (ret < 0) { + goto out; + } + } + + ret = 0; +out: + bdrv_delete(bs); + return ret; +} + +static int qcow2_create(const char *filename, QEMUOptionParameter *options) +{ + const char *backing_file = NULL; + const char *backing_fmt = NULL; + uint64_t sectors = 0; + int flags = 0; + size_t cluster_size = DEFAULT_CLUSTER_SIZE; + int prealloc = 0; + int version = 2; + + /* Read out options */ + while (options && options->name) { + if (!strcmp(options->name, BLOCK_OPT_SIZE)) { + sectors = options->value.n / 512; + } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FILE)) { + backing_file = options->value.s; + } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FMT)) { + backing_fmt = options->value.s; + } else if (!strcmp(options->name, BLOCK_OPT_ENCRYPT)) { + flags |= options->value.n ? BLOCK_FLAG_ENCRYPT : 0; + } else if (!strcmp(options->name, BLOCK_OPT_CLUSTER_SIZE)) { + if (options->value.n) { + cluster_size = options->value.n; + } + } else if (!strcmp(options->name, BLOCK_OPT_PREALLOC)) { + if (!options->value.s || !strcmp(options->value.s, "off")) { + prealloc = 0; + } else if (!strcmp(options->value.s, "metadata")) { + prealloc = 1; + } else { + fprintf(stderr, "Invalid preallocation mode: '%s'\n", + options->value.s); + return -EINVAL; + } + } else if (!strcmp(options->name, BLOCK_OPT_COMPAT_LEVEL)) { + if (!options->value.s || !strcmp(options->value.s, "0.10")) { + version = 2; + } else if (!strcmp(options->value.s, "1.1")) { + version = 3; + } else { + fprintf(stderr, "Invalid compatibility level: '%s'\n", + options->value.s); + return -EINVAL; + } + } else if (!strcmp(options->name, BLOCK_OPT_LAZY_REFCOUNTS)) { + flags |= options->value.n ? BLOCK_FLAG_LAZY_REFCOUNTS : 0; + } + options++; + } + + if (backing_file && prealloc) { + fprintf(stderr, "Backing file and preallocation cannot be used at " + "the same time\n"); + return -EINVAL; + } + + if (version < 3 && (flags & BLOCK_FLAG_LAZY_REFCOUNTS)) { + fprintf(stderr, "Lazy refcounts only supported with compatibility " + "level 1.1 and above (use compat=1.1 or greater)\n"); + return -EINVAL; + } + + return qcow2_create2(filename, sectors, backing_file, backing_fmt, flags, + cluster_size, prealloc, options, version); +} + +static int qcow2_make_empty(BlockDriverState *bs) +{ +#if 0 + /* XXX: not correct */ + BDRVQcowState *s = bs->opaque; + uint32_t l1_length = s->l1_size * sizeof(uint64_t); + int ret; + + memset(s->l1_table, 0, l1_length); + if (bdrv_pwrite(bs->file, s->l1_table_offset, s->l1_table, l1_length) < 0) + return -1; + ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length); + if (ret < 0) + return ret; + + l2_cache_reset(bs); +#endif + return 0; +} + +static coroutine_fn int qcow2_co_write_zeroes(BlockDriverState *bs, + int64_t sector_num, int nb_sectors) +{ + int ret; + BDRVQcowState *s = bs->opaque; + + /* Emulate misaligned zero writes */ + if (sector_num % s->cluster_sectors || nb_sectors % s->cluster_sectors) { + return -ENOTSUP; + } + + /* Whatever is left can use real zero clusters */ + qemu_co_mutex_lock(&s->lock); + ret = qcow2_zero_clusters(bs, sector_num << BDRV_SECTOR_BITS, + nb_sectors); + qemu_co_mutex_unlock(&s->lock); + + return ret; +} + +static coroutine_fn int qcow2_co_discard(BlockDriverState *bs, + int64_t sector_num, int nb_sectors) +{ + int ret; + BDRVQcowState *s = bs->opaque; + + qemu_co_mutex_lock(&s->lock); + ret = qcow2_discard_clusters(bs, sector_num << BDRV_SECTOR_BITS, + nb_sectors); + qemu_co_mutex_unlock(&s->lock); + return ret; +} + +static int qcow2_truncate(BlockDriverState *bs, int64_t offset) +{ + BDRVQcowState *s = bs->opaque; + int64_t new_l1_size; + int ret; + + if (offset & 511) { + error_report("The new size must be a multiple of 512"); + return -EINVAL; + } + + /* cannot proceed if image has snapshots */ + if (s->nb_snapshots) { + error_report("Can't resize an image which has snapshots"); + return -ENOTSUP; + } + + /* shrinking is currently not supported */ + if (offset < bs->total_sectors * 512) { + error_report("qcow2 doesn't support shrinking images yet"); + return -ENOTSUP; + } + + new_l1_size = size_to_l1(s, offset); + ret = qcow2_grow_l1_table(bs, new_l1_size, true); + if (ret < 0) { + return ret; + } + + /* write updated header.size */ + offset = cpu_to_be64(offset); + ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, size), + &offset, sizeof(uint64_t)); + if (ret < 0) { + return ret; + } + + s->l1_vm_state_index = new_l1_size; + return 0; +} + +/* XXX: put compressed sectors first, then all the cluster aligned + tables to avoid losing bytes in alignment */ +static int qcow2_write_compressed(BlockDriverState *bs, int64_t sector_num, + const uint8_t *buf, int nb_sectors) +{ + BDRVQcowState *s = bs->opaque; + z_stream strm; + int ret, out_len; + uint8_t *out_buf; + uint64_t cluster_offset; + + if (nb_sectors == 0) { + /* align end of file to a sector boundary to ease reading with + sector based I/Os */ + cluster_offset = bdrv_getlength(bs->file); + cluster_offset = (cluster_offset + 511) & ~511; + bdrv_truncate(bs->file, cluster_offset); + return 0; + } + + if (nb_sectors != s->cluster_sectors) { + ret = -EINVAL; + + /* Zero-pad last write if image size is not cluster aligned */ + if (sector_num + nb_sectors == bs->total_sectors && + nb_sectors < s->cluster_sectors) { + uint8_t *pad_buf = qemu_blockalign(bs, s->cluster_size); + memset(pad_buf, 0, s->cluster_size); + memcpy(pad_buf, buf, nb_sectors * BDRV_SECTOR_SIZE); + ret = qcow2_write_compressed(bs, sector_num, + pad_buf, s->cluster_sectors); + qemu_vfree(pad_buf); + } + return ret; + } + + out_buf = g_malloc(s->cluster_size + (s->cluster_size / 1000) + 128); + + /* best compression, small window, no zlib header */ + memset(&strm, 0, sizeof(strm)); + ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, + Z_DEFLATED, -12, + 9, Z_DEFAULT_STRATEGY); + if (ret != 0) { + ret = -EINVAL; + goto fail; + } + + strm.avail_in = s->cluster_size; + strm.next_in = (uint8_t *)buf; + strm.avail_out = s->cluster_size; + strm.next_out = out_buf; + + ret = deflate(&strm, Z_FINISH); + if (ret != Z_STREAM_END && ret != Z_OK) { + deflateEnd(&strm); + ret = -EINVAL; + goto fail; + } + out_len = strm.next_out - out_buf; + + deflateEnd(&strm); + + if (ret != Z_STREAM_END || out_len >= s->cluster_size) { + /* could not compress: write normal cluster */ + ret = bdrv_write(bs, sector_num, buf, s->cluster_sectors); + if (ret < 0) { + goto fail; + } + } else { + cluster_offset = qcow2_alloc_compressed_cluster_offset(bs, + sector_num << 9, out_len); + if (!cluster_offset) { + ret = -EIO; + goto fail; + } + cluster_offset &= s->cluster_offset_mask; + BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED); + ret = bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len); + if (ret < 0) { + goto fail; + } + } + + ret = 0; +fail: + g_free(out_buf); + return ret; +} + +static coroutine_fn int qcow2_co_flush_to_os(BlockDriverState *bs) +{ + BDRVQcowState *s = bs->opaque; + int ret; + + qemu_co_mutex_lock(&s->lock); + ret = qcow2_cache_flush(bs, s->l2_table_cache); + if (ret < 0) { + qemu_co_mutex_unlock(&s->lock); + return ret; + } + + if (qcow2_need_accurate_refcounts(s)) { + ret = qcow2_cache_flush(bs, s->refcount_block_cache); + if (ret < 0) { + qemu_co_mutex_unlock(&s->lock); + return ret; + } + } + qemu_co_mutex_unlock(&s->lock); + + return 0; +} + +static int64_t qcow2_vm_state_offset(BDRVQcowState *s) +{ + return (int64_t)s->l1_vm_state_index << (s->cluster_bits + s->l2_bits); +} + +static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) +{ + BDRVQcowState *s = bs->opaque; + bdi->cluster_size = s->cluster_size; + bdi->vm_state_offset = qcow2_vm_state_offset(s); + return 0; +} + +#if 0 +static void dump_refcounts(BlockDriverState *bs) +{ + BDRVQcowState *s = bs->opaque; + int64_t nb_clusters, k, k1, size; + int refcount; + + size = bdrv_getlength(bs->file); + nb_clusters = size_to_clusters(s, size); + for(k = 0; k < nb_clusters;) { + k1 = k; + refcount = get_refcount(bs, k); + k++; + while (k < nb_clusters && get_refcount(bs, k) == refcount) + k++; + printf("%" PRId64 ": refcount=%d nb=%" PRId64 "\n", k, refcount, + k - k1); + } +} +#endif + +static int qcow2_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, + int64_t pos) +{ + BDRVQcowState *s = bs->opaque; + int growable = bs->growable; + int ret; + + BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE); + bs->growable = 1; + ret = bdrv_pwritev(bs, qcow2_vm_state_offset(s) + pos, qiov); + bs->growable = growable; + + return ret; +} + +static int qcow2_load_vmstate(BlockDriverState *bs, uint8_t *buf, + int64_t pos, int size) +{ + BDRVQcowState *s = bs->opaque; + int growable = bs->growable; + int ret; + + BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD); + bs->growable = 1; + ret = bdrv_pread(bs, qcow2_vm_state_offset(s) + pos, buf, size); + bs->growable = growable; + + return ret; +} + +static QEMUOptionParameter qcow2_create_options[] = { + { + .name = BLOCK_OPT_SIZE, + .type = OPT_SIZE, + .help = "Virtual disk size" + }, + { + .name = BLOCK_OPT_COMPAT_LEVEL, + .type = OPT_STRING, + .help = "Compatibility level (0.10 or 1.1)" + }, + { + .name = BLOCK_OPT_BACKING_FILE, + .type = OPT_STRING, + .help = "File name of a base image" + }, + { + .name = BLOCK_OPT_BACKING_FMT, + .type = OPT_STRING, + .help = "Image format of the base image" + }, + { + .name = BLOCK_OPT_ENCRYPT, + .type = OPT_FLAG, + .help = "Encrypt the image" + }, + { + .name = BLOCK_OPT_CLUSTER_SIZE, + .type = OPT_SIZE, + .help = "qcow2 cluster size", + .value = { .n = DEFAULT_CLUSTER_SIZE }, + }, + { + .name = BLOCK_OPT_PREALLOC, + .type = OPT_STRING, + .help = "Preallocation mode (allowed values: off, metadata)" + }, + { + .name = BLOCK_OPT_LAZY_REFCOUNTS, + .type = OPT_FLAG, + .help = "Postpone refcount updates", + }, + { NULL } +}; + +static BlockDriver bdrv_qcow2 = { + .format_name = "qcow2", + .instance_size = sizeof(BDRVQcowState), + .bdrv_probe = qcow2_probe, + .bdrv_open = qcow2_open, + .bdrv_close = qcow2_close, + .bdrv_reopen_prepare = qcow2_reopen_prepare, + .bdrv_create = qcow2_create, + .bdrv_has_zero_init = bdrv_has_zero_init_1, + .bdrv_co_is_allocated = qcow2_co_is_allocated, + .bdrv_set_key = qcow2_set_key, + .bdrv_make_empty = qcow2_make_empty, + + .bdrv_co_readv = qcow2_co_readv, + .bdrv_co_writev = qcow2_co_writev, + .bdrv_co_flush_to_os = qcow2_co_flush_to_os, + + .bdrv_co_write_zeroes = qcow2_co_write_zeroes, + .bdrv_co_discard = qcow2_co_discard, + .bdrv_truncate = qcow2_truncate, + .bdrv_write_compressed = qcow2_write_compressed, + + .bdrv_snapshot_create = qcow2_snapshot_create, + .bdrv_snapshot_goto = qcow2_snapshot_goto, + .bdrv_snapshot_delete = qcow2_snapshot_delete, + .bdrv_snapshot_list = qcow2_snapshot_list, + .bdrv_snapshot_load_tmp = qcow2_snapshot_load_tmp, + .bdrv_get_info = qcow2_get_info, + + .bdrv_save_vmstate = qcow2_save_vmstate, + .bdrv_load_vmstate = qcow2_load_vmstate, + + .bdrv_change_backing_file = qcow2_change_backing_file, + + .bdrv_invalidate_cache = qcow2_invalidate_cache, + + .create_options = qcow2_create_options, + .bdrv_check = qcow2_check, +}; + +static void bdrv_qcow2_init(void) +{ + bdrv_register(&bdrv_qcow2); +} + +block_init(bdrv_qcow2_init); |