root / block / qcow2.c @ 3e21ffc9
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/*
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* Block driver for the QCOW version 2 format
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*
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* Copyright (c) 2004-2006 Fabrice Bellard
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "qemu-common.h" |
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#include "block_int.h" |
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#include "module.h" |
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#include <zlib.h> |
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#include "aes.h" |
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#include "block/qcow2.h" |
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|
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/*
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Differences with QCOW:
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- Support for multiple incremental snapshots.
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- Memory management by reference counts.
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- Clusters which have a reference count of one have the bit
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QCOW_OFLAG_COPIED to optimize write performance.
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- Size of compressed clusters is stored in sectors to reduce bit usage
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in the cluster offsets.
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- Support for storing additional data (such as the VM state) in the
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snapshots.
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- If a backing store is used, the cluster size is not constrained
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(could be backported to QCOW).
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- L2 tables have always a size of one cluster.
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*/
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|
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typedef struct { |
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uint32_t magic; |
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uint32_t len; |
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} QCowExtension; |
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#define QCOW_EXT_MAGIC_END 0 |
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#define QCOW_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA |
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|
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|
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|
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static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename) |
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{ |
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const QCowHeader *cow_header = (const void *)buf; |
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|
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if (buf_size >= sizeof(QCowHeader) && |
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be32_to_cpu(cow_header->magic) == QCOW_MAGIC && |
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be32_to_cpu(cow_header->version) == QCOW_VERSION) |
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return 100; |
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else
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return 0; |
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} |
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|
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|
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/*
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* read qcow2 extension and fill bs
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* start reading from start_offset
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* finish reading upon magic of value 0 or when end_offset reached
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* unknown magic is skipped (future extension this version knows nothing about)
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* return 0 upon success, non-0 otherwise
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*/
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static int qcow_read_extensions(BlockDriverState *bs, uint64_t start_offset, |
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uint64_t end_offset) |
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{ |
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BDRVQcowState *s = bs->opaque; |
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QCowExtension ext; |
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uint64_t offset; |
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|
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#ifdef DEBUG_EXT
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printf("qcow_read_extensions: start=%ld end=%ld\n", start_offset, end_offset);
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#endif
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offset = start_offset; |
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while (offset < end_offset) {
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#ifdef DEBUG_EXT
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/* Sanity check */
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if (offset > s->cluster_size)
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printf("qcow_handle_extension: suspicious offset %lu\n", offset);
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printf("attemting to read extended header in offset %lu\n", offset);
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#endif
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if (bdrv_pread(s->hd, offset, &ext, sizeof(ext)) != sizeof(ext)) { |
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fprintf(stderr, "qcow_handle_extension: ERROR: pread fail from offset %llu\n",
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(unsigned long long)offset); |
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return 1; |
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} |
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be32_to_cpus(&ext.magic); |
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be32_to_cpus(&ext.len); |
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offset += sizeof(ext);
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#ifdef DEBUG_EXT
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printf("ext.magic = 0x%x\n", ext.magic);
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#endif
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switch (ext.magic) {
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case QCOW_EXT_MAGIC_END:
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return 0; |
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case QCOW_EXT_MAGIC_BACKING_FORMAT:
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if (ext.len >= sizeof(bs->backing_format)) { |
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fprintf(stderr, "ERROR: ext_backing_format: len=%u too large"
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" (>=%zu)\n",
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ext.len, sizeof(bs->backing_format));
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return 2; |
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} |
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if (bdrv_pread(s->hd, offset , bs->backing_format,
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ext.len) != ext.len) |
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return 3; |
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bs->backing_format[ext.len] = '\0';
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#ifdef DEBUG_EXT
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printf("Qcow2: Got format extension %s\n", bs->backing_format);
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#endif
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offset += ((ext.len + 7) & ~7); |
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break;
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|
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default:
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/* unknown magic -- just skip it */
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offset += ((ext.len + 7) & ~7); |
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break;
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} |
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} |
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return 0; |
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} |
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|
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|
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static int qcow_open(BlockDriverState *bs, const char *filename, int flags) |
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{ |
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BDRVQcowState *s = bs->opaque; |
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int len, i, shift, ret;
|
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QCowHeader header; |
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uint64_t ext_end; |
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|
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ret = bdrv_file_open(&s->hd, filename, flags); |
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if (ret < 0) |
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return ret;
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if (bdrv_pread(s->hd, 0, &header, sizeof(header)) != sizeof(header)) |
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goto fail;
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be32_to_cpus(&header.magic); |
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be32_to_cpus(&header.version); |
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be64_to_cpus(&header.backing_file_offset); |
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be32_to_cpus(&header.backing_file_size); |
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be64_to_cpus(&header.size); |
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be32_to_cpus(&header.cluster_bits); |
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be32_to_cpus(&header.crypt_method); |
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be64_to_cpus(&header.l1_table_offset); |
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be32_to_cpus(&header.l1_size); |
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be64_to_cpus(&header.refcount_table_offset); |
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be32_to_cpus(&header.refcount_table_clusters); |
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be64_to_cpus(&header.snapshots_offset); |
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be32_to_cpus(&header.nb_snapshots); |
166 |
|
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if (header.magic != QCOW_MAGIC || header.version != QCOW_VERSION)
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goto fail;
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if (header.cluster_bits < MIN_CLUSTER_BITS ||
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header.cluster_bits > MAX_CLUSTER_BITS) |
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goto fail;
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if (header.crypt_method > QCOW_CRYPT_AES)
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goto fail;
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s->crypt_method_header = header.crypt_method; |
175 |
if (s->crypt_method_header)
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bs->encrypted = 1;
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s->cluster_bits = header.cluster_bits; |
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s->cluster_size = 1 << s->cluster_bits;
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s->cluster_sectors = 1 << (s->cluster_bits - 9); |
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s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */ |
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s->l2_size = 1 << s->l2_bits;
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bs->total_sectors = header.size / 512;
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s->csize_shift = (62 - (s->cluster_bits - 8)); |
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s->csize_mask = (1 << (s->cluster_bits - 8)) - 1; |
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s->cluster_offset_mask = (1LL << s->csize_shift) - 1; |
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s->refcount_table_offset = header.refcount_table_offset; |
187 |
s->refcount_table_size = |
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header.refcount_table_clusters << (s->cluster_bits - 3);
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|
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s->snapshots_offset = header.snapshots_offset; |
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s->nb_snapshots = header.nb_snapshots; |
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/* read the level 1 table */
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s->l1_size = header.l1_size; |
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shift = s->cluster_bits + s->l2_bits; |
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s->l1_vm_state_index = (header.size + (1LL << shift) - 1) >> shift; |
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/* the L1 table must contain at least enough entries to put
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header.size bytes */
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if (s->l1_size < s->l1_vm_state_index)
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goto fail;
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s->l1_table_offset = header.l1_table_offset; |
202 |
if (s->l1_size > 0) { |
203 |
s->l1_table = qemu_mallocz( |
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align_offset(s->l1_size * sizeof(uint64_t), 512)); |
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if (bdrv_pread(s->hd, s->l1_table_offset, s->l1_table, s->l1_size * sizeof(uint64_t)) != |
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s->l1_size * sizeof(uint64_t))
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goto fail;
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for(i = 0;i < s->l1_size; i++) { |
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be64_to_cpus(&s->l1_table[i]); |
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} |
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} |
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/* alloc L2 cache */
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s->l2_cache = qemu_malloc(s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
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s->cluster_cache = qemu_malloc(s->cluster_size); |
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/* one more sector for decompressed data alignment */
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s->cluster_data = qemu_malloc(QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size |
217 |
+ 512);
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s->cluster_cache_offset = -1;
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|
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if (qcow2_refcount_init(bs) < 0) |
221 |
goto fail;
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|
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QLIST_INIT(&s->cluster_allocs); |
224 |
|
225 |
/* read qcow2 extensions */
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if (header.backing_file_offset)
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ext_end = header.backing_file_offset; |
228 |
else
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ext_end = s->cluster_size; |
230 |
if (qcow_read_extensions(bs, sizeof(header), ext_end)) |
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goto fail;
|
232 |
|
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/* read the backing file name */
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if (header.backing_file_offset != 0) { |
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len = header.backing_file_size; |
236 |
if (len > 1023) |
237 |
len = 1023;
|
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if (bdrv_pread(s->hd, header.backing_file_offset, bs->backing_file, len) != len)
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goto fail;
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240 |
bs->backing_file[len] = '\0';
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} |
242 |
if (qcow2_read_snapshots(bs) < 0) |
243 |
goto fail;
|
244 |
|
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#ifdef DEBUG_ALLOC
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qcow2_check_refcounts(bs); |
247 |
#endif
|
248 |
return 0; |
249 |
|
250 |
fail:
|
251 |
qcow2_free_snapshots(bs); |
252 |
qcow2_refcount_close(bs); |
253 |
qemu_free(s->l1_table); |
254 |
qemu_free(s->l2_cache); |
255 |
qemu_free(s->cluster_cache); |
256 |
qemu_free(s->cluster_data); |
257 |
bdrv_delete(s->hd); |
258 |
return -1; |
259 |
} |
260 |
|
261 |
static int qcow_set_key(BlockDriverState *bs, const char *key) |
262 |
{ |
263 |
BDRVQcowState *s = bs->opaque; |
264 |
uint8_t keybuf[16];
|
265 |
int len, i;
|
266 |
|
267 |
memset(keybuf, 0, 16); |
268 |
len = strlen(key); |
269 |
if (len > 16) |
270 |
len = 16;
|
271 |
/* XXX: we could compress the chars to 7 bits to increase
|
272 |
entropy */
|
273 |
for(i = 0;i < len;i++) { |
274 |
keybuf[i] = key[i]; |
275 |
} |
276 |
s->crypt_method = s->crypt_method_header; |
277 |
|
278 |
if (AES_set_encrypt_key(keybuf, 128, &s->aes_encrypt_key) != 0) |
279 |
return -1; |
280 |
if (AES_set_decrypt_key(keybuf, 128, &s->aes_decrypt_key) != 0) |
281 |
return -1; |
282 |
#if 0
|
283 |
/* test */
|
284 |
{
|
285 |
uint8_t in[16];
|
286 |
uint8_t out[16];
|
287 |
uint8_t tmp[16];
|
288 |
for(i=0;i<16;i++)
|
289 |
in[i] = i;
|
290 |
AES_encrypt(in, tmp, &s->aes_encrypt_key);
|
291 |
AES_decrypt(tmp, out, &s->aes_decrypt_key);
|
292 |
for(i = 0; i < 16; i++)
|
293 |
printf(" %02x", tmp[i]);
|
294 |
printf("\n");
|
295 |
for(i = 0; i < 16; i++)
|
296 |
printf(" %02x", out[i]);
|
297 |
printf("\n");
|
298 |
}
|
299 |
#endif
|
300 |
return 0; |
301 |
} |
302 |
|
303 |
static int qcow_is_allocated(BlockDriverState *bs, int64_t sector_num, |
304 |
int nb_sectors, int *pnum) |
305 |
{ |
306 |
uint64_t cluster_offset; |
307 |
|
308 |
*pnum = nb_sectors; |
309 |
cluster_offset = qcow2_get_cluster_offset(bs, sector_num << 9, pnum);
|
310 |
|
311 |
return (cluster_offset != 0); |
312 |
} |
313 |
|
314 |
/* handle reading after the end of the backing file */
|
315 |
int qcow2_backing_read1(BlockDriverState *bs,
|
316 |
int64_t sector_num, uint8_t *buf, int nb_sectors)
|
317 |
{ |
318 |
int n1;
|
319 |
if ((sector_num + nb_sectors) <= bs->total_sectors)
|
320 |
return nb_sectors;
|
321 |
if (sector_num >= bs->total_sectors)
|
322 |
n1 = 0;
|
323 |
else
|
324 |
n1 = bs->total_sectors - sector_num; |
325 |
memset(buf + n1 * 512, 0, 512 * (nb_sectors - n1)); |
326 |
return n1;
|
327 |
} |
328 |
|
329 |
typedef struct QCowAIOCB { |
330 |
BlockDriverAIOCB common; |
331 |
int64_t sector_num; |
332 |
QEMUIOVector *qiov; |
333 |
uint8_t *buf; |
334 |
void *orig_buf;
|
335 |
int nb_sectors;
|
336 |
int n;
|
337 |
uint64_t cluster_offset; |
338 |
uint8_t *cluster_data; |
339 |
BlockDriverAIOCB *hd_aiocb; |
340 |
struct iovec hd_iov;
|
341 |
QEMUIOVector hd_qiov; |
342 |
QEMUBH *bh; |
343 |
QCowL2Meta l2meta; |
344 |
QLIST_ENTRY(QCowAIOCB) next_depend; |
345 |
} QCowAIOCB; |
346 |
|
347 |
static void qcow_aio_cancel(BlockDriverAIOCB *blockacb) |
348 |
{ |
349 |
QCowAIOCB *acb = (QCowAIOCB *)blockacb; |
350 |
if (acb->hd_aiocb)
|
351 |
bdrv_aio_cancel(acb->hd_aiocb); |
352 |
qemu_aio_release(acb); |
353 |
} |
354 |
|
355 |
static AIOPool qcow_aio_pool = {
|
356 |
.aiocb_size = sizeof(QCowAIOCB),
|
357 |
.cancel = qcow_aio_cancel, |
358 |
}; |
359 |
|
360 |
static void qcow_aio_read_cb(void *opaque, int ret); |
361 |
static void qcow_aio_read_bh(void *opaque) |
362 |
{ |
363 |
QCowAIOCB *acb = opaque; |
364 |
qemu_bh_delete(acb->bh); |
365 |
acb->bh = NULL;
|
366 |
qcow_aio_read_cb(opaque, 0);
|
367 |
} |
368 |
|
369 |
static int qcow_schedule_bh(QEMUBHFunc *cb, QCowAIOCB *acb) |
370 |
{ |
371 |
if (acb->bh)
|
372 |
return -EIO;
|
373 |
|
374 |
acb->bh = qemu_bh_new(cb, acb); |
375 |
if (!acb->bh)
|
376 |
return -EIO;
|
377 |
|
378 |
qemu_bh_schedule(acb->bh); |
379 |
|
380 |
return 0; |
381 |
} |
382 |
|
383 |
static void qcow_aio_read_cb(void *opaque, int ret) |
384 |
{ |
385 |
QCowAIOCB *acb = opaque; |
386 |
BlockDriverState *bs = acb->common.bs; |
387 |
BDRVQcowState *s = bs->opaque; |
388 |
int index_in_cluster, n1;
|
389 |
|
390 |
acb->hd_aiocb = NULL;
|
391 |
if (ret < 0) |
392 |
goto done;
|
393 |
|
394 |
/* post process the read buffer */
|
395 |
if (!acb->cluster_offset) {
|
396 |
/* nothing to do */
|
397 |
} else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) { |
398 |
/* nothing to do */
|
399 |
} else {
|
400 |
if (s->crypt_method) {
|
401 |
qcow2_encrypt_sectors(s, acb->sector_num, acb->buf, acb->buf, |
402 |
acb->n, 0,
|
403 |
&s->aes_decrypt_key); |
404 |
} |
405 |
} |
406 |
|
407 |
acb->nb_sectors -= acb->n; |
408 |
acb->sector_num += acb->n; |
409 |
acb->buf += acb->n * 512;
|
410 |
|
411 |
if (acb->nb_sectors == 0) { |
412 |
/* request completed */
|
413 |
ret = 0;
|
414 |
goto done;
|
415 |
} |
416 |
|
417 |
/* prepare next AIO request */
|
418 |
acb->n = acb->nb_sectors; |
419 |
acb->cluster_offset = |
420 |
qcow2_get_cluster_offset(bs, acb->sector_num << 9, &acb->n);
|
421 |
index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
|
422 |
|
423 |
if (!acb->cluster_offset) {
|
424 |
if (bs->backing_hd) {
|
425 |
/* read from the base image */
|
426 |
n1 = qcow2_backing_read1(bs->backing_hd, acb->sector_num, |
427 |
acb->buf, acb->n); |
428 |
if (n1 > 0) { |
429 |
acb->hd_iov.iov_base = (void *)acb->buf;
|
430 |
acb->hd_iov.iov_len = acb->n * 512;
|
431 |
qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
|
432 |
acb->hd_aiocb = bdrv_aio_readv(bs->backing_hd, acb->sector_num, |
433 |
&acb->hd_qiov, acb->n, |
434 |
qcow_aio_read_cb, acb); |
435 |
if (acb->hd_aiocb == NULL) |
436 |
goto done;
|
437 |
} else {
|
438 |
ret = qcow_schedule_bh(qcow_aio_read_bh, acb); |
439 |
if (ret < 0) |
440 |
goto done;
|
441 |
} |
442 |
} else {
|
443 |
/* Note: in this case, no need to wait */
|
444 |
memset(acb->buf, 0, 512 * acb->n); |
445 |
ret = qcow_schedule_bh(qcow_aio_read_bh, acb); |
446 |
if (ret < 0) |
447 |
goto done;
|
448 |
} |
449 |
} else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) { |
450 |
/* add AIO support for compressed blocks ? */
|
451 |
if (qcow2_decompress_cluster(s, acb->cluster_offset) < 0) |
452 |
goto done;
|
453 |
memcpy(acb->buf, |
454 |
s->cluster_cache + index_in_cluster * 512, 512 * acb->n); |
455 |
ret = qcow_schedule_bh(qcow_aio_read_bh, acb); |
456 |
if (ret < 0) |
457 |
goto done;
|
458 |
} else {
|
459 |
if ((acb->cluster_offset & 511) != 0) { |
460 |
ret = -EIO; |
461 |
goto done;
|
462 |
} |
463 |
|
464 |
acb->hd_iov.iov_base = (void *)acb->buf;
|
465 |
acb->hd_iov.iov_len = acb->n * 512;
|
466 |
qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
|
467 |
acb->hd_aiocb = bdrv_aio_readv(s->hd, |
468 |
(acb->cluster_offset >> 9) + index_in_cluster,
|
469 |
&acb->hd_qiov, acb->n, qcow_aio_read_cb, acb); |
470 |
if (acb->hd_aiocb == NULL) |
471 |
goto done;
|
472 |
} |
473 |
|
474 |
return;
|
475 |
done:
|
476 |
if (acb->qiov->niov > 1) { |
477 |
qemu_iovec_from_buffer(acb->qiov, acb->orig_buf, acb->qiov->size); |
478 |
qemu_vfree(acb->orig_buf); |
479 |
} |
480 |
acb->common.cb(acb->common.opaque, ret); |
481 |
qemu_aio_release(acb); |
482 |
} |
483 |
|
484 |
static QCowAIOCB *qcow_aio_setup(BlockDriverState *bs,
|
485 |
int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
|
486 |
BlockDriverCompletionFunc *cb, void *opaque, int is_write) |
487 |
{ |
488 |
QCowAIOCB *acb; |
489 |
|
490 |
acb = qemu_aio_get(&qcow_aio_pool, bs, cb, opaque); |
491 |
if (!acb)
|
492 |
return NULL; |
493 |
acb->hd_aiocb = NULL;
|
494 |
acb->sector_num = sector_num; |
495 |
acb->qiov = qiov; |
496 |
if (qiov->niov > 1) { |
497 |
acb->buf = acb->orig_buf = qemu_blockalign(bs, qiov->size); |
498 |
if (is_write)
|
499 |
qemu_iovec_to_buffer(qiov, acb->buf); |
500 |
} else {
|
501 |
acb->buf = (uint8_t *)qiov->iov->iov_base; |
502 |
} |
503 |
acb->nb_sectors = nb_sectors; |
504 |
acb->n = 0;
|
505 |
acb->cluster_offset = 0;
|
506 |
acb->l2meta.nb_clusters = 0;
|
507 |
QLIST_INIT(&acb->l2meta.dependent_requests); |
508 |
return acb;
|
509 |
} |
510 |
|
511 |
static BlockDriverAIOCB *qcow_aio_readv(BlockDriverState *bs,
|
512 |
int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
|
513 |
BlockDriverCompletionFunc *cb, void *opaque)
|
514 |
{ |
515 |
QCowAIOCB *acb; |
516 |
|
517 |
acb = qcow_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 0);
|
518 |
if (!acb)
|
519 |
return NULL; |
520 |
|
521 |
qcow_aio_read_cb(acb, 0);
|
522 |
return &acb->common;
|
523 |
} |
524 |
|
525 |
static void qcow_aio_write_cb(void *opaque, int ret); |
526 |
|
527 |
static void run_dependent_requests(QCowL2Meta *m) |
528 |
{ |
529 |
QCowAIOCB *req; |
530 |
QCowAIOCB *next; |
531 |
|
532 |
/* Take the request off the list of running requests */
|
533 |
if (m->nb_clusters != 0) { |
534 |
QLIST_REMOVE(m, next_in_flight); |
535 |
} |
536 |
|
537 |
/*
|
538 |
* Restart all dependent requests.
|
539 |
* Can't use QLIST_FOREACH here - the next link might not be the same
|
540 |
* any more after the callback (request could depend on a different
|
541 |
* request now)
|
542 |
*/
|
543 |
for (req = m->dependent_requests.lh_first; req != NULL; req = next) { |
544 |
next = req->next_depend.le_next; |
545 |
qcow_aio_write_cb(req, 0);
|
546 |
} |
547 |
|
548 |
/* Empty the list for the next part of the request */
|
549 |
QLIST_INIT(&m->dependent_requests); |
550 |
} |
551 |
|
552 |
static void qcow_aio_write_cb(void *opaque, int ret) |
553 |
{ |
554 |
QCowAIOCB *acb = opaque; |
555 |
BlockDriverState *bs = acb->common.bs; |
556 |
BDRVQcowState *s = bs->opaque; |
557 |
int index_in_cluster;
|
558 |
const uint8_t *src_buf;
|
559 |
int n_end;
|
560 |
|
561 |
acb->hd_aiocb = NULL;
|
562 |
|
563 |
if (ret >= 0) { |
564 |
ret = qcow2_alloc_cluster_link_l2(bs, acb->cluster_offset, &acb->l2meta); |
565 |
} |
566 |
|
567 |
run_dependent_requests(&acb->l2meta); |
568 |
|
569 |
if (ret < 0) |
570 |
goto done;
|
571 |
|
572 |
acb->nb_sectors -= acb->n; |
573 |
acb->sector_num += acb->n; |
574 |
acb->buf += acb->n * 512;
|
575 |
|
576 |
if (acb->nb_sectors == 0) { |
577 |
/* request completed */
|
578 |
ret = 0;
|
579 |
goto done;
|
580 |
} |
581 |
|
582 |
index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
|
583 |
n_end = index_in_cluster + acb->nb_sectors; |
584 |
if (s->crypt_method &&
|
585 |
n_end > QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors) |
586 |
n_end = QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors; |
587 |
|
588 |
acb->cluster_offset = qcow2_alloc_cluster_offset(bs, acb->sector_num << 9,
|
589 |
index_in_cluster, |
590 |
n_end, &acb->n, &acb->l2meta); |
591 |
|
592 |
/* Need to wait for another request? If so, we are done for now. */
|
593 |
if (!acb->cluster_offset && acb->l2meta.depends_on != NULL) { |
594 |
QLIST_INSERT_HEAD(&acb->l2meta.depends_on->dependent_requests, |
595 |
acb, next_depend); |
596 |
return;
|
597 |
} |
598 |
|
599 |
if (!acb->cluster_offset || (acb->cluster_offset & 511) != 0) { |
600 |
ret = -EIO; |
601 |
goto done;
|
602 |
} |
603 |
if (s->crypt_method) {
|
604 |
if (!acb->cluster_data) {
|
605 |
acb->cluster_data = qemu_mallocz(QCOW_MAX_CRYPT_CLUSTERS * |
606 |
s->cluster_size); |
607 |
} |
608 |
qcow2_encrypt_sectors(s, acb->sector_num, acb->cluster_data, acb->buf, |
609 |
acb->n, 1, &s->aes_encrypt_key);
|
610 |
src_buf = acb->cluster_data; |
611 |
} else {
|
612 |
src_buf = acb->buf; |
613 |
} |
614 |
acb->hd_iov.iov_base = (void *)src_buf;
|
615 |
acb->hd_iov.iov_len = acb->n * 512;
|
616 |
qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
|
617 |
acb->hd_aiocb = bdrv_aio_writev(s->hd, |
618 |
(acb->cluster_offset >> 9) + index_in_cluster,
|
619 |
&acb->hd_qiov, acb->n, |
620 |
qcow_aio_write_cb, acb); |
621 |
if (acb->hd_aiocb == NULL) |
622 |
goto done;
|
623 |
|
624 |
return;
|
625 |
|
626 |
done:
|
627 |
if (acb->qiov->niov > 1) |
628 |
qemu_vfree(acb->orig_buf); |
629 |
acb->common.cb(acb->common.opaque, ret); |
630 |
qemu_aio_release(acb); |
631 |
} |
632 |
|
633 |
static BlockDriverAIOCB *qcow_aio_writev(BlockDriverState *bs,
|
634 |
int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
|
635 |
BlockDriverCompletionFunc *cb, void *opaque)
|
636 |
{ |
637 |
BDRVQcowState *s = bs->opaque; |
638 |
QCowAIOCB *acb; |
639 |
|
640 |
s->cluster_cache_offset = -1; /* disable compressed cache */ |
641 |
|
642 |
acb = qcow_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 1);
|
643 |
if (!acb)
|
644 |
return NULL; |
645 |
|
646 |
qcow_aio_write_cb(acb, 0);
|
647 |
return &acb->common;
|
648 |
} |
649 |
|
650 |
static void qcow_close(BlockDriverState *bs) |
651 |
{ |
652 |
BDRVQcowState *s = bs->opaque; |
653 |
qemu_free(s->l1_table); |
654 |
qemu_free(s->l2_cache); |
655 |
qemu_free(s->cluster_cache); |
656 |
qemu_free(s->cluster_data); |
657 |
qcow2_refcount_close(bs); |
658 |
bdrv_delete(s->hd); |
659 |
} |
660 |
|
661 |
static int get_bits_from_size(size_t size) |
662 |
{ |
663 |
int res = 0; |
664 |
|
665 |
if (size == 0) { |
666 |
return -1; |
667 |
} |
668 |
|
669 |
while (size != 1) { |
670 |
/* Not a power of two */
|
671 |
if (size & 1) { |
672 |
return -1; |
673 |
} |
674 |
|
675 |
size >>= 1;
|
676 |
res++; |
677 |
} |
678 |
|
679 |
return res;
|
680 |
} |
681 |
|
682 |
|
683 |
static int preallocate(BlockDriverState *bs) |
684 |
{ |
685 |
BDRVQcowState *s = bs->opaque; |
686 |
uint64_t cluster_offset = 0;
|
687 |
uint64_t nb_sectors; |
688 |
uint64_t offset; |
689 |
int num;
|
690 |
QCowL2Meta meta; |
691 |
|
692 |
nb_sectors = bdrv_getlength(bs) >> 9;
|
693 |
offset = 0;
|
694 |
QLIST_INIT(&meta.dependent_requests); |
695 |
|
696 |
while (nb_sectors) {
|
697 |
num = MIN(nb_sectors, INT_MAX >> 9);
|
698 |
cluster_offset = qcow2_alloc_cluster_offset(bs, offset, 0, num, &num,
|
699 |
&meta); |
700 |
|
701 |
if (cluster_offset == 0) { |
702 |
return -1; |
703 |
} |
704 |
|
705 |
if (qcow2_alloc_cluster_link_l2(bs, cluster_offset, &meta) < 0) { |
706 |
qcow2_free_any_clusters(bs, cluster_offset, meta.nb_clusters); |
707 |
return -1; |
708 |
} |
709 |
|
710 |
/* There are no dependent requests, but we need to remove our request
|
711 |
* from the list of in-flight requests */
|
712 |
run_dependent_requests(&meta); |
713 |
|
714 |
/* TODO Preallocate data if requested */
|
715 |
|
716 |
nb_sectors -= num; |
717 |
offset += num << 9;
|
718 |
} |
719 |
|
720 |
/*
|
721 |
* It is expected that the image file is large enough to actually contain
|
722 |
* all of the allocated clusters (otherwise we get failing reads after
|
723 |
* EOF). Extend the image to the last allocated sector.
|
724 |
*/
|
725 |
if (cluster_offset != 0) { |
726 |
uint8_t buf[512];
|
727 |
memset(buf, 0, 512); |
728 |
bdrv_write(s->hd, (cluster_offset >> 9) + num - 1, buf, 1); |
729 |
} |
730 |
|
731 |
return 0; |
732 |
} |
733 |
|
734 |
static int qcow_create2(const char *filename, int64_t total_size, |
735 |
const char *backing_file, const char *backing_format, |
736 |
int flags, size_t cluster_size, int prealloc) |
737 |
{ |
738 |
|
739 |
int fd, header_size, backing_filename_len, l1_size, i, shift, l2_bits;
|
740 |
int ref_clusters, backing_format_len = 0; |
741 |
QCowHeader header; |
742 |
uint64_t tmp, offset; |
743 |
QCowCreateState s1, *s = &s1; |
744 |
QCowExtension ext_bf = {0, 0}; |
745 |
|
746 |
|
747 |
memset(s, 0, sizeof(*s)); |
748 |
|
749 |
fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
|
750 |
if (fd < 0) |
751 |
return -1; |
752 |
memset(&header, 0, sizeof(header)); |
753 |
header.magic = cpu_to_be32(QCOW_MAGIC); |
754 |
header.version = cpu_to_be32(QCOW_VERSION); |
755 |
header.size = cpu_to_be64(total_size * 512);
|
756 |
header_size = sizeof(header);
|
757 |
backing_filename_len = 0;
|
758 |
if (backing_file) {
|
759 |
if (backing_format) {
|
760 |
ext_bf.magic = QCOW_EXT_MAGIC_BACKING_FORMAT; |
761 |
backing_format_len = strlen(backing_format); |
762 |
ext_bf.len = (backing_format_len + 7) & ~7; |
763 |
header_size += ((sizeof(ext_bf) + ext_bf.len + 7) & ~7); |
764 |
} |
765 |
header.backing_file_offset = cpu_to_be64(header_size); |
766 |
backing_filename_len = strlen(backing_file); |
767 |
header.backing_file_size = cpu_to_be32(backing_filename_len); |
768 |
header_size += backing_filename_len; |
769 |
} |
770 |
|
771 |
/* Cluster size */
|
772 |
s->cluster_bits = get_bits_from_size(cluster_size); |
773 |
if (s->cluster_bits < MIN_CLUSTER_BITS ||
|
774 |
s->cluster_bits > MAX_CLUSTER_BITS) |
775 |
{ |
776 |
fprintf(stderr, "Cluster size must be a power of two between "
|
777 |
"%d and %dk\n",
|
778 |
1 << MIN_CLUSTER_BITS,
|
779 |
1 << (MAX_CLUSTER_BITS - 10)); |
780 |
return -EINVAL;
|
781 |
} |
782 |
s->cluster_size = 1 << s->cluster_bits;
|
783 |
|
784 |
header.cluster_bits = cpu_to_be32(s->cluster_bits); |
785 |
header_size = (header_size + 7) & ~7; |
786 |
if (flags & BLOCK_FLAG_ENCRYPT) {
|
787 |
header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES); |
788 |
} else {
|
789 |
header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); |
790 |
} |
791 |
l2_bits = s->cluster_bits - 3;
|
792 |
shift = s->cluster_bits + l2_bits; |
793 |
l1_size = (((total_size * 512) + (1LL << shift) - 1) >> shift); |
794 |
offset = align_offset(header_size, s->cluster_size); |
795 |
s->l1_table_offset = offset; |
796 |
header.l1_table_offset = cpu_to_be64(s->l1_table_offset); |
797 |
header.l1_size = cpu_to_be32(l1_size); |
798 |
offset += align_offset(l1_size * sizeof(uint64_t), s->cluster_size);
|
799 |
|
800 |
s->refcount_table = qemu_mallocz(s->cluster_size); |
801 |
|
802 |
s->refcount_table_offset = offset; |
803 |
header.refcount_table_offset = cpu_to_be64(offset); |
804 |
header.refcount_table_clusters = cpu_to_be32(1);
|
805 |
offset += s->cluster_size; |
806 |
s->refcount_block_offset = offset; |
807 |
|
808 |
/* count how many refcount blocks needed */
|
809 |
tmp = offset >> s->cluster_bits; |
810 |
ref_clusters = (tmp >> (s->cluster_bits - REFCOUNT_SHIFT)) + 1;
|
811 |
for (i=0; i < ref_clusters; i++) { |
812 |
s->refcount_table[i] = cpu_to_be64(offset); |
813 |
offset += s->cluster_size; |
814 |
} |
815 |
|
816 |
s->refcount_block = qemu_mallocz(ref_clusters * s->cluster_size); |
817 |
|
818 |
/* update refcounts */
|
819 |
qcow2_create_refcount_update(s, 0, header_size);
|
820 |
qcow2_create_refcount_update(s, s->l1_table_offset, |
821 |
l1_size * sizeof(uint64_t));
|
822 |
qcow2_create_refcount_update(s, s->refcount_table_offset, s->cluster_size); |
823 |
qcow2_create_refcount_update(s, s->refcount_block_offset, |
824 |
ref_clusters * s->cluster_size); |
825 |
|
826 |
/* write all the data */
|
827 |
write(fd, &header, sizeof(header));
|
828 |
if (backing_file) {
|
829 |
if (backing_format_len) {
|
830 |
char zero[16]; |
831 |
int d = ext_bf.len - backing_format_len;
|
832 |
|
833 |
memset(zero, 0, sizeof(zero)); |
834 |
cpu_to_be32s(&ext_bf.magic); |
835 |
cpu_to_be32s(&ext_bf.len); |
836 |
write(fd, &ext_bf, sizeof(ext_bf));
|
837 |
write(fd, backing_format, backing_format_len); |
838 |
if (d>0) { |
839 |
write(fd, zero, d); |
840 |
} |
841 |
} |
842 |
write(fd, backing_file, backing_filename_len); |
843 |
} |
844 |
lseek(fd, s->l1_table_offset, SEEK_SET); |
845 |
tmp = 0;
|
846 |
for(i = 0;i < l1_size; i++) { |
847 |
write(fd, &tmp, sizeof(tmp));
|
848 |
} |
849 |
lseek(fd, s->refcount_table_offset, SEEK_SET); |
850 |
write(fd, s->refcount_table, s->cluster_size); |
851 |
|
852 |
lseek(fd, s->refcount_block_offset, SEEK_SET); |
853 |
write(fd, s->refcount_block, ref_clusters * s->cluster_size); |
854 |
|
855 |
qemu_free(s->refcount_table); |
856 |
qemu_free(s->refcount_block); |
857 |
close(fd); |
858 |
|
859 |
/* Preallocate metadata */
|
860 |
if (prealloc) {
|
861 |
BlockDriverState *bs; |
862 |
bs = bdrv_new("");
|
863 |
bdrv_open(bs, filename, BDRV_O_CACHE_WB); |
864 |
preallocate(bs); |
865 |
bdrv_close(bs); |
866 |
} |
867 |
|
868 |
return 0; |
869 |
} |
870 |
|
871 |
static int qcow_create(const char *filename, QEMUOptionParameter *options) |
872 |
{ |
873 |
const char *backing_file = NULL; |
874 |
const char *backing_fmt = NULL; |
875 |
uint64_t sectors = 0;
|
876 |
int flags = 0; |
877 |
size_t cluster_size = 65536;
|
878 |
int prealloc = 0; |
879 |
|
880 |
/* Read out options */
|
881 |
while (options && options->name) {
|
882 |
if (!strcmp(options->name, BLOCK_OPT_SIZE)) {
|
883 |
sectors = options->value.n / 512;
|
884 |
} else if (!strcmp(options->name, BLOCK_OPT_BACKING_FILE)) { |
885 |
backing_file = options->value.s; |
886 |
} else if (!strcmp(options->name, BLOCK_OPT_BACKING_FMT)) { |
887 |
backing_fmt = options->value.s; |
888 |
} else if (!strcmp(options->name, BLOCK_OPT_ENCRYPT)) { |
889 |
flags |= options->value.n ? BLOCK_FLAG_ENCRYPT : 0;
|
890 |
} else if (!strcmp(options->name, BLOCK_OPT_CLUSTER_SIZE)) { |
891 |
if (options->value.n) {
|
892 |
cluster_size = options->value.n; |
893 |
} |
894 |
} else if (!strcmp(options->name, BLOCK_OPT_PREALLOC)) { |
895 |
if (!options->value.s || !strcmp(options->value.s, "off")) { |
896 |
prealloc = 0;
|
897 |
} else if (!strcmp(options->value.s, "metadata")) { |
898 |
prealloc = 1;
|
899 |
} else {
|
900 |
fprintf(stderr, "Invalid preallocation mode: '%s'\n",
|
901 |
options->value.s); |
902 |
return -EINVAL;
|
903 |
} |
904 |
} |
905 |
options++; |
906 |
} |
907 |
|
908 |
if (backing_file && prealloc) {
|
909 |
fprintf(stderr, "Backing file and preallocation cannot be used at "
|
910 |
"the same time\n");
|
911 |
return -EINVAL;
|
912 |
} |
913 |
|
914 |
return qcow_create2(filename, sectors, backing_file, backing_fmt, flags,
|
915 |
cluster_size, prealloc); |
916 |
} |
917 |
|
918 |
static int qcow_make_empty(BlockDriverState *bs) |
919 |
{ |
920 |
#if 0
|
921 |
/* XXX: not correct */
|
922 |
BDRVQcowState *s = bs->opaque;
|
923 |
uint32_t l1_length = s->l1_size * sizeof(uint64_t);
|
924 |
int ret;
|
925 |
|
926 |
memset(s->l1_table, 0, l1_length);
|
927 |
if (bdrv_pwrite(s->hd, s->l1_table_offset, s->l1_table, l1_length) < 0)
|
928 |
return -1;
|
929 |
ret = bdrv_truncate(s->hd, s->l1_table_offset + l1_length);
|
930 |
if (ret < 0)
|
931 |
return ret;
|
932 |
|
933 |
l2_cache_reset(bs);
|
934 |
#endif
|
935 |
return 0; |
936 |
} |
937 |
|
938 |
/* XXX: put compressed sectors first, then all the cluster aligned
|
939 |
tables to avoid losing bytes in alignment */
|
940 |
static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num, |
941 |
const uint8_t *buf, int nb_sectors) |
942 |
{ |
943 |
BDRVQcowState *s = bs->opaque; |
944 |
z_stream strm; |
945 |
int ret, out_len;
|
946 |
uint8_t *out_buf; |
947 |
uint64_t cluster_offset; |
948 |
|
949 |
if (nb_sectors == 0) { |
950 |
/* align end of file to a sector boundary to ease reading with
|
951 |
sector based I/Os */
|
952 |
cluster_offset = bdrv_getlength(s->hd); |
953 |
cluster_offset = (cluster_offset + 511) & ~511; |
954 |
bdrv_truncate(s->hd, cluster_offset); |
955 |
return 0; |
956 |
} |
957 |
|
958 |
if (nb_sectors != s->cluster_sectors)
|
959 |
return -EINVAL;
|
960 |
|
961 |
out_buf = qemu_malloc(s->cluster_size + (s->cluster_size / 1000) + 128); |
962 |
|
963 |
/* best compression, small window, no zlib header */
|
964 |
memset(&strm, 0, sizeof(strm)); |
965 |
ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, |
966 |
Z_DEFLATED, -12,
|
967 |
9, Z_DEFAULT_STRATEGY);
|
968 |
if (ret != 0) { |
969 |
qemu_free(out_buf); |
970 |
return -1; |
971 |
} |
972 |
|
973 |
strm.avail_in = s->cluster_size; |
974 |
strm.next_in = (uint8_t *)buf; |
975 |
strm.avail_out = s->cluster_size; |
976 |
strm.next_out = out_buf; |
977 |
|
978 |
ret = deflate(&strm, Z_FINISH); |
979 |
if (ret != Z_STREAM_END && ret != Z_OK) {
|
980 |
qemu_free(out_buf); |
981 |
deflateEnd(&strm); |
982 |
return -1; |
983 |
} |
984 |
out_len = strm.next_out - out_buf; |
985 |
|
986 |
deflateEnd(&strm); |
987 |
|
988 |
if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
|
989 |
/* could not compress: write normal cluster */
|
990 |
bdrv_write(bs, sector_num, buf, s->cluster_sectors); |
991 |
} else {
|
992 |
cluster_offset = qcow2_alloc_compressed_cluster_offset(bs, |
993 |
sector_num << 9, out_len);
|
994 |
if (!cluster_offset)
|
995 |
return -1; |
996 |
cluster_offset &= s->cluster_offset_mask; |
997 |
if (bdrv_pwrite(s->hd, cluster_offset, out_buf, out_len) != out_len) {
|
998 |
qemu_free(out_buf); |
999 |
return -1; |
1000 |
} |
1001 |
} |
1002 |
|
1003 |
qemu_free(out_buf); |
1004 |
return 0; |
1005 |
} |
1006 |
|
1007 |
static void qcow_flush(BlockDriverState *bs) |
1008 |
{ |
1009 |
BDRVQcowState *s = bs->opaque; |
1010 |
bdrv_flush(s->hd); |
1011 |
} |
1012 |
|
1013 |
static int64_t qcow_vm_state_offset(BDRVQcowState *s)
|
1014 |
{ |
1015 |
return (int64_t)s->l1_vm_state_index << (s->cluster_bits + s->l2_bits);
|
1016 |
} |
1017 |
|
1018 |
static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) |
1019 |
{ |
1020 |
BDRVQcowState *s = bs->opaque; |
1021 |
bdi->cluster_size = s->cluster_size; |
1022 |
bdi->vm_state_offset = qcow_vm_state_offset(s); |
1023 |
return 0; |
1024 |
} |
1025 |
|
1026 |
|
1027 |
static int qcow_check(BlockDriverState *bs) |
1028 |
{ |
1029 |
return qcow2_check_refcounts(bs);
|
1030 |
} |
1031 |
|
1032 |
#if 0
|
1033 |
static void dump_refcounts(BlockDriverState *bs)
|
1034 |
{
|
1035 |
BDRVQcowState *s = bs->opaque;
|
1036 |
int64_t nb_clusters, k, k1, size;
|
1037 |
int refcount;
|
1038 |
|
1039 |
size = bdrv_getlength(s->hd);
|
1040 |
nb_clusters = size_to_clusters(s, size);
|
1041 |
for(k = 0; k < nb_clusters;) {
|
1042 |
k1 = k;
|
1043 |
refcount = get_refcount(bs, k);
|
1044 |
k++;
|
1045 |
while (k < nb_clusters && get_refcount(bs, k) == refcount)
|
1046 |
k++;
|
1047 |
printf("%lld: refcount=%d nb=%lld\n", k, refcount, k - k1);
|
1048 |
}
|
1049 |
}
|
1050 |
#endif
|
1051 |
|
1052 |
static int qcow_save_vmstate(BlockDriverState *bs, const uint8_t *buf, |
1053 |
int64_t pos, int size)
|
1054 |
{ |
1055 |
BDRVQcowState *s = bs->opaque; |
1056 |
int growable = bs->growable;
|
1057 |
|
1058 |
bs->growable = 1;
|
1059 |
bdrv_pwrite(bs, qcow_vm_state_offset(s) + pos, buf, size); |
1060 |
bs->growable = growable; |
1061 |
|
1062 |
return size;
|
1063 |
} |
1064 |
|
1065 |
static int qcow_load_vmstate(BlockDriverState *bs, uint8_t *buf, |
1066 |
int64_t pos, int size)
|
1067 |
{ |
1068 |
BDRVQcowState *s = bs->opaque; |
1069 |
int growable = bs->growable;
|
1070 |
int ret;
|
1071 |
|
1072 |
bs->growable = 1;
|
1073 |
ret = bdrv_pread(bs, qcow_vm_state_offset(s) + pos, buf, size); |
1074 |
bs->growable = growable; |
1075 |
|
1076 |
return ret;
|
1077 |
} |
1078 |
|
1079 |
static QEMUOptionParameter qcow_create_options[] = {
|
1080 |
{ |
1081 |
.name = BLOCK_OPT_SIZE, |
1082 |
.type = OPT_SIZE, |
1083 |
.help = "Virtual disk size"
|
1084 |
}, |
1085 |
{ |
1086 |
.name = BLOCK_OPT_BACKING_FILE, |
1087 |
.type = OPT_STRING, |
1088 |
.help = "File name of a base image"
|
1089 |
}, |
1090 |
{ |
1091 |
.name = BLOCK_OPT_BACKING_FMT, |
1092 |
.type = OPT_STRING, |
1093 |
.help = "Image format of the base image"
|
1094 |
}, |
1095 |
{ |
1096 |
.name = BLOCK_OPT_ENCRYPT, |
1097 |
.type = OPT_FLAG, |
1098 |
.help = "Encrypt the image"
|
1099 |
}, |
1100 |
{ |
1101 |
.name = BLOCK_OPT_CLUSTER_SIZE, |
1102 |
.type = OPT_SIZE, |
1103 |
.help = "qcow2 cluster size"
|
1104 |
}, |
1105 |
{ |
1106 |
.name = BLOCK_OPT_PREALLOC, |
1107 |
.type = OPT_STRING, |
1108 |
.help = "Preallocation mode (allowed values: off, metadata)"
|
1109 |
}, |
1110 |
{ NULL }
|
1111 |
}; |
1112 |
|
1113 |
static BlockDriver bdrv_qcow2 = {
|
1114 |
.format_name = "qcow2",
|
1115 |
.instance_size = sizeof(BDRVQcowState),
|
1116 |
.bdrv_probe = qcow_probe, |
1117 |
.bdrv_open = qcow_open, |
1118 |
.bdrv_close = qcow_close, |
1119 |
.bdrv_create = qcow_create, |
1120 |
.bdrv_flush = qcow_flush, |
1121 |
.bdrv_is_allocated = qcow_is_allocated, |
1122 |
.bdrv_set_key = qcow_set_key, |
1123 |
.bdrv_make_empty = qcow_make_empty, |
1124 |
|
1125 |
.bdrv_aio_readv = qcow_aio_readv, |
1126 |
.bdrv_aio_writev = qcow_aio_writev, |
1127 |
.bdrv_write_compressed = qcow_write_compressed, |
1128 |
|
1129 |
.bdrv_snapshot_create = qcow2_snapshot_create, |
1130 |
.bdrv_snapshot_goto = qcow2_snapshot_goto, |
1131 |
.bdrv_snapshot_delete = qcow2_snapshot_delete, |
1132 |
.bdrv_snapshot_list = qcow2_snapshot_list, |
1133 |
.bdrv_get_info = qcow_get_info, |
1134 |
|
1135 |
.bdrv_save_vmstate = qcow_save_vmstate, |
1136 |
.bdrv_load_vmstate = qcow_load_vmstate, |
1137 |
|
1138 |
.create_options = qcow_create_options, |
1139 |
.bdrv_check = qcow_check, |
1140 |
}; |
1141 |
|
1142 |
static void bdrv_qcow2_init(void) |
1143 |
{ |
1144 |
bdrv_register(&bdrv_qcow2); |
1145 |
} |
1146 |
|
1147 |
block_init(bdrv_qcow2_init); |