root / block / qcow2.c @ e0d9c6f9
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/*
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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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#include "qemu-error.h" |
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|
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/*
|
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Differences with QCOW:
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|
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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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|
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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 QCOW2_EXT_MAGIC_END 0 |
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#define QCOW2_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA |
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|
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static int qcow2_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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} |
| 67 |
|
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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 qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset, |
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uint64_t end_offset) |
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{
|
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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("qcow2_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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|
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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("qcow2_read_extension: suspicious offset %lu\n", offset);
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|
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printf("attemting to read extended header in offset %lu\n", offset);
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#endif
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|
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if (bdrv_pread(bs->file, offset, &ext, sizeof(ext)) != sizeof(ext)) { |
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fprintf(stderr, "qcow2_read_extension: ERROR: "
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"pread fail from offset %" PRIu64 "\n", |
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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 QCOW2_EXT_MAGIC_END:
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return 0; |
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|
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case QCOW2_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(bs->file, 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 = ((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 = ((offset + ext.len + 7) & ~7); |
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break;
|
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} |
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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 qcow2_open(BlockDriverState *bs, int flags) |
| 141 |
{
|
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BDRVQcowState *s = bs->opaque; |
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int len, i, ret = 0; |
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QCowHeader header; |
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uint64_t ext_end; |
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bool writethrough;
|
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|
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ret = bdrv_pread(bs->file, 0, &header, sizeof(header)); |
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if (ret < 0) { |
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goto fail;
|
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} |
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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); |
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|
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if (header.magic != QCOW_MAGIC || header.version != QCOW_VERSION) {
|
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ret = -EINVAL; |
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goto fail;
|
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} |
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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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ret = -EINVAL; |
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goto fail;
|
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} |
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if (header.crypt_method > QCOW_CRYPT_AES) {
|
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ret = -EINVAL; |
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goto fail;
|
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} |
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s->crypt_method_header = header.crypt_method; |
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if (s->crypt_method_header) {
|
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bs->encrypted = 1;
|
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} |
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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; |
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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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|
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/* read the level 1 table */
|
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s->l1_size = header.l1_size; |
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s->l1_vm_state_index = size_to_l1(s, header.size); |
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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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ret = -EINVAL; |
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goto fail;
|
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} |
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s->l1_table_offset = header.l1_table_offset; |
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if (s->l1_size > 0) { |
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s->l1_table = qemu_mallocz( |
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align_offset(s->l1_size * sizeof(uint64_t), 512)); |
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ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table, |
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s->l1_size * sizeof(uint64_t));
|
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if (ret < 0) { |
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goto fail;
|
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} |
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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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|
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/* alloc L2 table/refcount block cache */
|
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writethrough = ((flags & BDRV_O_CACHE_MASK) == 0);
|
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s->l2_table_cache = qcow2_cache_create(bs, L2_CACHE_SIZE, writethrough); |
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s->refcount_block_cache = qcow2_cache_create(bs, REFCOUNT_CACHE_SIZE, |
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writethrough); |
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|
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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 |
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+ 512);
|
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s->cluster_cache_offset = -1;
|
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|
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ret = qcow2_refcount_init(bs); |
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if (ret != 0) { |
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goto fail;
|
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} |
| 238 |
|
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QLIST_INIT(&s->cluster_allocs); |
| 240 |
|
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/* read qcow2 extensions */
|
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if (header.backing_file_offset) {
|
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ext_end = header.backing_file_offset; |
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} else {
|
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ext_end = s->cluster_size; |
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} |
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if (qcow2_read_extensions(bs, sizeof(header), ext_end)) { |
| 248 |
ret = -EINVAL; |
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goto fail;
|
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} |
| 251 |
|
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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; |
| 255 |
if (len > 1023) { |
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len = 1023;
|
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} |
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ret = bdrv_pread(bs->file, header.backing_file_offset, |
| 259 |
bs->backing_file, len); |
| 260 |
if (ret < 0) { |
| 261 |
goto fail;
|
| 262 |
} |
| 263 |
bs->backing_file[len] = '\0';
|
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} |
| 265 |
if (qcow2_read_snapshots(bs) < 0) { |
| 266 |
ret = -EINVAL; |
| 267 |
goto fail;
|
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} |
| 269 |
|
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#ifdef DEBUG_ALLOC
|
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qcow2_check_refcounts(bs); |
| 272 |
#endif
|
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return ret;
|
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|
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fail:
|
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qcow2_free_snapshots(bs); |
| 277 |
qcow2_refcount_close(bs); |
| 278 |
qemu_free(s->l1_table); |
| 279 |
if (s->l2_table_cache) {
|
| 280 |
qcow2_cache_destroy(bs, s->l2_table_cache); |
| 281 |
} |
| 282 |
qemu_free(s->cluster_cache); |
| 283 |
qemu_free(s->cluster_data); |
| 284 |
return ret;
|
| 285 |
} |
| 286 |
|
| 287 |
static int qcow2_set_key(BlockDriverState *bs, const char *key) |
| 288 |
{
|
| 289 |
BDRVQcowState *s = bs->opaque; |
| 290 |
uint8_t keybuf[16];
|
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int len, i;
|
| 292 |
|
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memset(keybuf, 0, 16); |
| 294 |
len = strlen(key); |
| 295 |
if (len > 16) |
| 296 |
len = 16;
|
| 297 |
/* XXX: we could compress the chars to 7 bits to increase
|
| 298 |
entropy */
|
| 299 |
for(i = 0;i < len;i++) { |
| 300 |
keybuf[i] = key[i]; |
| 301 |
} |
| 302 |
s->crypt_method = s->crypt_method_header; |
| 303 |
|
| 304 |
if (AES_set_encrypt_key(keybuf, 128, &s->aes_encrypt_key) != 0) |
| 305 |
return -1; |
| 306 |
if (AES_set_decrypt_key(keybuf, 128, &s->aes_decrypt_key) != 0) |
| 307 |
return -1; |
| 308 |
#if 0
|
| 309 |
/* test */
|
| 310 |
{
|
| 311 |
uint8_t in[16];
|
| 312 |
uint8_t out[16];
|
| 313 |
uint8_t tmp[16];
|
| 314 |
for(i=0;i<16;i++)
|
| 315 |
in[i] = i;
|
| 316 |
AES_encrypt(in, tmp, &s->aes_encrypt_key);
|
| 317 |
AES_decrypt(tmp, out, &s->aes_decrypt_key);
|
| 318 |
for(i = 0; i < 16; i++)
|
| 319 |
printf(" %02x", tmp[i]);
|
| 320 |
printf("\n");
|
| 321 |
for(i = 0; i < 16; i++)
|
| 322 |
printf(" %02x", out[i]);
|
| 323 |
printf("\n");
|
| 324 |
}
|
| 325 |
#endif
|
| 326 |
return 0; |
| 327 |
} |
| 328 |
|
| 329 |
static int qcow2_is_allocated(BlockDriverState *bs, int64_t sector_num, |
| 330 |
int nb_sectors, int *pnum) |
| 331 |
{
|
| 332 |
uint64_t cluster_offset; |
| 333 |
int ret;
|
| 334 |
|
| 335 |
*pnum = nb_sectors; |
| 336 |
/* FIXME We can get errors here, but the bdrv_is_allocated interface can't
|
| 337 |
* pass them on today */
|
| 338 |
ret = qcow2_get_cluster_offset(bs, sector_num << 9, pnum, &cluster_offset);
|
| 339 |
if (ret < 0) { |
| 340 |
*pnum = 0;
|
| 341 |
} |
| 342 |
|
| 343 |
return (cluster_offset != 0); |
| 344 |
} |
| 345 |
|
| 346 |
/* handle reading after the end of the backing file */
|
| 347 |
int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov,
|
| 348 |
int64_t sector_num, int nb_sectors)
|
| 349 |
{
|
| 350 |
int n1;
|
| 351 |
if ((sector_num + nb_sectors) <= bs->total_sectors)
|
| 352 |
return nb_sectors;
|
| 353 |
if (sector_num >= bs->total_sectors)
|
| 354 |
n1 = 0;
|
| 355 |
else
|
| 356 |
n1 = bs->total_sectors - sector_num; |
| 357 |
|
| 358 |
qemu_iovec_memset_skip(qiov, 0, 512 * (nb_sectors - n1), 512 * n1); |
| 359 |
|
| 360 |
return n1;
|
| 361 |
} |
| 362 |
|
| 363 |
typedef struct QCowAIOCB { |
| 364 |
BlockDriverAIOCB common; |
| 365 |
int64_t sector_num; |
| 366 |
QEMUIOVector *qiov; |
| 367 |
int remaining_sectors;
|
| 368 |
int cur_nr_sectors; /* number of sectors in current iteration */ |
| 369 |
uint64_t bytes_done; |
| 370 |
uint64_t cluster_offset; |
| 371 |
uint8_t *cluster_data; |
| 372 |
BlockDriverAIOCB *hd_aiocb; |
| 373 |
QEMUIOVector hd_qiov; |
| 374 |
QEMUBH *bh; |
| 375 |
QCowL2Meta l2meta; |
| 376 |
QLIST_ENTRY(QCowAIOCB) next_depend; |
| 377 |
} QCowAIOCB; |
| 378 |
|
| 379 |
static void qcow2_aio_cancel(BlockDriverAIOCB *blockacb) |
| 380 |
{
|
| 381 |
QCowAIOCB *acb = container_of(blockacb, QCowAIOCB, common); |
| 382 |
if (acb->hd_aiocb)
|
| 383 |
bdrv_aio_cancel(acb->hd_aiocb); |
| 384 |
qemu_aio_release(acb); |
| 385 |
} |
| 386 |
|
| 387 |
static AIOPool qcow2_aio_pool = {
|
| 388 |
.aiocb_size = sizeof(QCowAIOCB),
|
| 389 |
.cancel = qcow2_aio_cancel, |
| 390 |
}; |
| 391 |
|
| 392 |
static void qcow2_aio_read_cb(void *opaque, int ret); |
| 393 |
static void qcow2_aio_read_bh(void *opaque) |
| 394 |
{
|
| 395 |
QCowAIOCB *acb = opaque; |
| 396 |
qemu_bh_delete(acb->bh); |
| 397 |
acb->bh = NULL;
|
| 398 |
qcow2_aio_read_cb(opaque, 0);
|
| 399 |
} |
| 400 |
|
| 401 |
static int qcow2_schedule_bh(QEMUBHFunc *cb, QCowAIOCB *acb) |
| 402 |
{
|
| 403 |
if (acb->bh)
|
| 404 |
return -EIO;
|
| 405 |
|
| 406 |
acb->bh = qemu_bh_new(cb, acb); |
| 407 |
if (!acb->bh)
|
| 408 |
return -EIO;
|
| 409 |
|
| 410 |
qemu_bh_schedule(acb->bh); |
| 411 |
|
| 412 |
return 0; |
| 413 |
} |
| 414 |
|
| 415 |
static void qcow2_aio_read_cb(void *opaque, int ret) |
| 416 |
{
|
| 417 |
QCowAIOCB *acb = opaque; |
| 418 |
BlockDriverState *bs = acb->common.bs; |
| 419 |
BDRVQcowState *s = bs->opaque; |
| 420 |
int index_in_cluster, n1;
|
| 421 |
|
| 422 |
acb->hd_aiocb = NULL;
|
| 423 |
if (ret < 0) |
| 424 |
goto done;
|
| 425 |
|
| 426 |
/* post process the read buffer */
|
| 427 |
if (!acb->cluster_offset) {
|
| 428 |
/* nothing to do */
|
| 429 |
} else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) { |
| 430 |
/* nothing to do */
|
| 431 |
} else {
|
| 432 |
if (s->crypt_method) {
|
| 433 |
qcow2_encrypt_sectors(s, acb->sector_num, acb->cluster_data, |
| 434 |
acb->cluster_data, acb->cur_nr_sectors, 0, &s->aes_decrypt_key);
|
| 435 |
qemu_iovec_reset(&acb->hd_qiov); |
| 436 |
qemu_iovec_copy(&acb->hd_qiov, acb->qiov, acb->bytes_done, |
| 437 |
acb->cur_nr_sectors * 512);
|
| 438 |
qemu_iovec_from_buffer(&acb->hd_qiov, acb->cluster_data, |
| 439 |
512 * acb->cur_nr_sectors);
|
| 440 |
} |
| 441 |
} |
| 442 |
|
| 443 |
acb->remaining_sectors -= acb->cur_nr_sectors; |
| 444 |
acb->sector_num += acb->cur_nr_sectors; |
| 445 |
acb->bytes_done += acb->cur_nr_sectors * 512;
|
| 446 |
|
| 447 |
if (acb->remaining_sectors == 0) { |
| 448 |
/* request completed */
|
| 449 |
ret = 0;
|
| 450 |
goto done;
|
| 451 |
} |
| 452 |
|
| 453 |
/* prepare next AIO request */
|
| 454 |
acb->cur_nr_sectors = acb->remaining_sectors; |
| 455 |
if (s->crypt_method) {
|
| 456 |
acb->cur_nr_sectors = MIN(acb->cur_nr_sectors, |
| 457 |
QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors); |
| 458 |
} |
| 459 |
|
| 460 |
ret = qcow2_get_cluster_offset(bs, acb->sector_num << 9,
|
| 461 |
&acb->cur_nr_sectors, &acb->cluster_offset); |
| 462 |
if (ret < 0) { |
| 463 |
goto done;
|
| 464 |
} |
| 465 |
|
| 466 |
index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
|
| 467 |
|
| 468 |
qemu_iovec_reset(&acb->hd_qiov); |
| 469 |
qemu_iovec_copy(&acb->hd_qiov, acb->qiov, acb->bytes_done, |
| 470 |
acb->cur_nr_sectors * 512);
|
| 471 |
|
| 472 |
if (!acb->cluster_offset) {
|
| 473 |
|
| 474 |
if (bs->backing_hd) {
|
| 475 |
/* read from the base image */
|
| 476 |
n1 = qcow2_backing_read1(bs->backing_hd, &acb->hd_qiov, |
| 477 |
acb->sector_num, acb->cur_nr_sectors); |
| 478 |
if (n1 > 0) { |
| 479 |
BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO); |
| 480 |
acb->hd_aiocb = bdrv_aio_readv(bs->backing_hd, acb->sector_num, |
| 481 |
&acb->hd_qiov, n1, qcow2_aio_read_cb, acb); |
| 482 |
if (acb->hd_aiocb == NULL) |
| 483 |
goto done;
|
| 484 |
} else {
|
| 485 |
ret = qcow2_schedule_bh(qcow2_aio_read_bh, acb); |
| 486 |
if (ret < 0) |
| 487 |
goto done;
|
| 488 |
} |
| 489 |
} else {
|
| 490 |
/* Note: in this case, no need to wait */
|
| 491 |
qemu_iovec_memset(&acb->hd_qiov, 0, 512 * acb->cur_nr_sectors); |
| 492 |
ret = qcow2_schedule_bh(qcow2_aio_read_bh, acb); |
| 493 |
if (ret < 0) |
| 494 |
goto done;
|
| 495 |
} |
| 496 |
} else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) { |
| 497 |
/* add AIO support for compressed blocks ? */
|
| 498 |
if (qcow2_decompress_cluster(bs, acb->cluster_offset) < 0) |
| 499 |
goto done;
|
| 500 |
|
| 501 |
qemu_iovec_from_buffer(&acb->hd_qiov, |
| 502 |
s->cluster_cache + index_in_cluster * 512,
|
| 503 |
512 * acb->cur_nr_sectors);
|
| 504 |
|
| 505 |
ret = qcow2_schedule_bh(qcow2_aio_read_bh, acb); |
| 506 |
if (ret < 0) |
| 507 |
goto done;
|
| 508 |
} else {
|
| 509 |
if ((acb->cluster_offset & 511) != 0) { |
| 510 |
ret = -EIO; |
| 511 |
goto done;
|
| 512 |
} |
| 513 |
|
| 514 |
if (s->crypt_method) {
|
| 515 |
/*
|
| 516 |
* For encrypted images, read everything into a temporary
|
| 517 |
* contiguous buffer on which the AES functions can work.
|
| 518 |
*/
|
| 519 |
if (!acb->cluster_data) {
|
| 520 |
acb->cluster_data = |
| 521 |
qemu_mallocz(QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); |
| 522 |
} |
| 523 |
|
| 524 |
assert(acb->cur_nr_sectors <= |
| 525 |
QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors); |
| 526 |
qemu_iovec_reset(&acb->hd_qiov); |
| 527 |
qemu_iovec_add(&acb->hd_qiov, acb->cluster_data, |
| 528 |
512 * acb->cur_nr_sectors);
|
| 529 |
} |
| 530 |
|
| 531 |
BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); |
| 532 |
acb->hd_aiocb = bdrv_aio_readv(bs->file, |
| 533 |
(acb->cluster_offset >> 9) + index_in_cluster,
|
| 534 |
&acb->hd_qiov, acb->cur_nr_sectors, |
| 535 |
qcow2_aio_read_cb, acb); |
| 536 |
if (acb->hd_aiocb == NULL) { |
| 537 |
ret = -EIO; |
| 538 |
goto done;
|
| 539 |
} |
| 540 |
} |
| 541 |
|
| 542 |
return;
|
| 543 |
done:
|
| 544 |
acb->common.cb(acb->common.opaque, ret); |
| 545 |
qemu_iovec_destroy(&acb->hd_qiov); |
| 546 |
qemu_aio_release(acb); |
| 547 |
} |
| 548 |
|
| 549 |
static QCowAIOCB *qcow2_aio_setup(BlockDriverState *bs, int64_t sector_num,
|
| 550 |
QEMUIOVector *qiov, int nb_sectors,
|
| 551 |
BlockDriverCompletionFunc *cb, |
| 552 |
void *opaque, int is_write) |
| 553 |
{
|
| 554 |
QCowAIOCB *acb; |
| 555 |
|
| 556 |
acb = qemu_aio_get(&qcow2_aio_pool, bs, cb, opaque); |
| 557 |
if (!acb)
|
| 558 |
return NULL; |
| 559 |
acb->hd_aiocb = NULL;
|
| 560 |
acb->sector_num = sector_num; |
| 561 |
acb->qiov = qiov; |
| 562 |
|
| 563 |
qemu_iovec_init(&acb->hd_qiov, qiov->niov); |
| 564 |
|
| 565 |
acb->bytes_done = 0;
|
| 566 |
acb->remaining_sectors = nb_sectors; |
| 567 |
acb->cur_nr_sectors = 0;
|
| 568 |
acb->cluster_offset = 0;
|
| 569 |
acb->l2meta.nb_clusters = 0;
|
| 570 |
QLIST_INIT(&acb->l2meta.dependent_requests); |
| 571 |
return acb;
|
| 572 |
} |
| 573 |
|
| 574 |
static BlockDriverAIOCB *qcow2_aio_readv(BlockDriverState *bs,
|
| 575 |
int64_t sector_num, |
| 576 |
QEMUIOVector *qiov, int nb_sectors,
|
| 577 |
BlockDriverCompletionFunc *cb, |
| 578 |
void *opaque)
|
| 579 |
{
|
| 580 |
QCowAIOCB *acb; |
| 581 |
|
| 582 |
acb = qcow2_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 0);
|
| 583 |
if (!acb)
|
| 584 |
return NULL; |
| 585 |
|
| 586 |
qcow2_aio_read_cb(acb, 0);
|
| 587 |
return &acb->common;
|
| 588 |
} |
| 589 |
|
| 590 |
static void qcow2_aio_write_cb(void *opaque, int ret); |
| 591 |
|
| 592 |
static void run_dependent_requests(QCowL2Meta *m) |
| 593 |
{
|
| 594 |
QCowAIOCB *req; |
| 595 |
QCowAIOCB *next; |
| 596 |
|
| 597 |
/* Take the request off the list of running requests */
|
| 598 |
if (m->nb_clusters != 0) { |
| 599 |
QLIST_REMOVE(m, next_in_flight); |
| 600 |
} |
| 601 |
|
| 602 |
/* Restart all dependent requests */
|
| 603 |
QLIST_FOREACH_SAFE(req, &m->dependent_requests, next_depend, next) {
|
| 604 |
qcow2_aio_write_cb(req, 0);
|
| 605 |
} |
| 606 |
|
| 607 |
/* Empty the list for the next part of the request */
|
| 608 |
QLIST_INIT(&m->dependent_requests); |
| 609 |
} |
| 610 |
|
| 611 |
static void qcow2_aio_write_cb(void *opaque, int ret) |
| 612 |
{
|
| 613 |
QCowAIOCB *acb = opaque; |
| 614 |
BlockDriverState *bs = acb->common.bs; |
| 615 |
BDRVQcowState *s = bs->opaque; |
| 616 |
int index_in_cluster;
|
| 617 |
int n_end;
|
| 618 |
|
| 619 |
acb->hd_aiocb = NULL;
|
| 620 |
|
| 621 |
if (ret >= 0) { |
| 622 |
ret = qcow2_alloc_cluster_link_l2(bs, &acb->l2meta); |
| 623 |
} |
| 624 |
|
| 625 |
run_dependent_requests(&acb->l2meta); |
| 626 |
|
| 627 |
if (ret < 0) |
| 628 |
goto done;
|
| 629 |
|
| 630 |
acb->remaining_sectors -= acb->cur_nr_sectors; |
| 631 |
acb->sector_num += acb->cur_nr_sectors; |
| 632 |
acb->bytes_done += acb->cur_nr_sectors * 512;
|
| 633 |
|
| 634 |
if (acb->remaining_sectors == 0) { |
| 635 |
/* request completed */
|
| 636 |
ret = 0;
|
| 637 |
goto done;
|
| 638 |
} |
| 639 |
|
| 640 |
index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
|
| 641 |
n_end = index_in_cluster + acb->remaining_sectors; |
| 642 |
if (s->crypt_method &&
|
| 643 |
n_end > QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors) |
| 644 |
n_end = QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors; |
| 645 |
|
| 646 |
ret = qcow2_alloc_cluster_offset(bs, acb->sector_num << 9,
|
| 647 |
index_in_cluster, n_end, &acb->cur_nr_sectors, &acb->l2meta); |
| 648 |
if (ret < 0) { |
| 649 |
goto done;
|
| 650 |
} |
| 651 |
|
| 652 |
acb->cluster_offset = acb->l2meta.cluster_offset; |
| 653 |
|
| 654 |
/* Need to wait for another request? If so, we are done for now. */
|
| 655 |
if (acb->l2meta.nb_clusters == 0 && acb->l2meta.depends_on != NULL) { |
| 656 |
QLIST_INSERT_HEAD(&acb->l2meta.depends_on->dependent_requests, |
| 657 |
acb, next_depend); |
| 658 |
return;
|
| 659 |
} |
| 660 |
|
| 661 |
assert((acb->cluster_offset & 511) == 0); |
| 662 |
|
| 663 |
qemu_iovec_reset(&acb->hd_qiov); |
| 664 |
qemu_iovec_copy(&acb->hd_qiov, acb->qiov, acb->bytes_done, |
| 665 |
acb->cur_nr_sectors * 512);
|
| 666 |
|
| 667 |
if (s->crypt_method) {
|
| 668 |
if (!acb->cluster_data) {
|
| 669 |
acb->cluster_data = qemu_mallocz(QCOW_MAX_CRYPT_CLUSTERS * |
| 670 |
s->cluster_size); |
| 671 |
} |
| 672 |
|
| 673 |
assert(acb->hd_qiov.size <= QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); |
| 674 |
qemu_iovec_to_buffer(&acb->hd_qiov, acb->cluster_data); |
| 675 |
|
| 676 |
qcow2_encrypt_sectors(s, acb->sector_num, acb->cluster_data, |
| 677 |
acb->cluster_data, acb->cur_nr_sectors, 1, &s->aes_encrypt_key);
|
| 678 |
|
| 679 |
qemu_iovec_reset(&acb->hd_qiov); |
| 680 |
qemu_iovec_add(&acb->hd_qiov, acb->cluster_data, |
| 681 |
acb->cur_nr_sectors * 512);
|
| 682 |
} |
| 683 |
|
| 684 |
BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); |
| 685 |
acb->hd_aiocb = bdrv_aio_writev(bs->file, |
| 686 |
(acb->cluster_offset >> 9) + index_in_cluster,
|
| 687 |
&acb->hd_qiov, acb->cur_nr_sectors, |
| 688 |
qcow2_aio_write_cb, acb); |
| 689 |
if (acb->hd_aiocb == NULL) { |
| 690 |
ret = -EIO; |
| 691 |
goto fail;
|
| 692 |
} |
| 693 |
|
| 694 |
return;
|
| 695 |
|
| 696 |
fail:
|
| 697 |
if (acb->l2meta.nb_clusters != 0) { |
| 698 |
QLIST_REMOVE(&acb->l2meta, next_in_flight); |
| 699 |
} |
| 700 |
done:
|
| 701 |
acb->common.cb(acb->common.opaque, ret); |
| 702 |
qemu_iovec_destroy(&acb->hd_qiov); |
| 703 |
qemu_aio_release(acb); |
| 704 |
} |
| 705 |
|
| 706 |
static BlockDriverAIOCB *qcow2_aio_writev(BlockDriverState *bs,
|
| 707 |
int64_t sector_num, |
| 708 |
QEMUIOVector *qiov, int nb_sectors,
|
| 709 |
BlockDriverCompletionFunc *cb, |
| 710 |
void *opaque)
|
| 711 |
{
|
| 712 |
BDRVQcowState *s = bs->opaque; |
| 713 |
QCowAIOCB *acb; |
| 714 |
|
| 715 |
s->cluster_cache_offset = -1; /* disable compressed cache */ |
| 716 |
|
| 717 |
acb = qcow2_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 1);
|
| 718 |
if (!acb)
|
| 719 |
return NULL; |
| 720 |
|
| 721 |
qcow2_aio_write_cb(acb, 0);
|
| 722 |
return &acb->common;
|
| 723 |
} |
| 724 |
|
| 725 |
static void qcow2_close(BlockDriverState *bs) |
| 726 |
{
|
| 727 |
BDRVQcowState *s = bs->opaque; |
| 728 |
qemu_free(s->l1_table); |
| 729 |
|
| 730 |
qcow2_cache_flush(bs, s->l2_table_cache); |
| 731 |
qcow2_cache_flush(bs, s->refcount_block_cache); |
| 732 |
|
| 733 |
qcow2_cache_destroy(bs, s->l2_table_cache); |
| 734 |
qcow2_cache_destroy(bs, s->refcount_block_cache); |
| 735 |
|
| 736 |
qemu_free(s->cluster_cache); |
| 737 |
qemu_free(s->cluster_data); |
| 738 |
qcow2_refcount_close(bs); |
| 739 |
} |
| 740 |
|
| 741 |
/*
|
| 742 |
* Updates the variable length parts of the qcow2 header, i.e. the backing file
|
| 743 |
* name and all extensions. qcow2 was not designed to allow such changes, so if
|
| 744 |
* we run out of space (we can only use the first cluster) this function may
|
| 745 |
* fail.
|
| 746 |
*
|
| 747 |
* Returns 0 on success, -errno in error cases.
|
| 748 |
*/
|
| 749 |
static int qcow2_update_ext_header(BlockDriverState *bs, |
| 750 |
const char *backing_file, const char *backing_fmt) |
| 751 |
{
|
| 752 |
size_t backing_file_len = 0;
|
| 753 |
size_t backing_fmt_len = 0;
|
| 754 |
BDRVQcowState *s = bs->opaque; |
| 755 |
QCowExtension ext_backing_fmt = {0, 0};
|
| 756 |
int ret;
|
| 757 |
|
| 758 |
/* Backing file format doesn't make sense without a backing file */
|
| 759 |
if (backing_fmt && !backing_file) {
|
| 760 |
return -EINVAL;
|
| 761 |
} |
| 762 |
|
| 763 |
/* Prepare the backing file format extension if needed */
|
| 764 |
if (backing_fmt) {
|
| 765 |
ext_backing_fmt.len = cpu_to_be32(strlen(backing_fmt)); |
| 766 |
ext_backing_fmt.magic = cpu_to_be32(QCOW2_EXT_MAGIC_BACKING_FORMAT); |
| 767 |
backing_fmt_len = ((sizeof(ext_backing_fmt)
|
| 768 |
+ strlen(backing_fmt) + 7) & ~7); |
| 769 |
} |
| 770 |
|
| 771 |
/* Check if we can fit the new header into the first cluster */
|
| 772 |
if (backing_file) {
|
| 773 |
backing_file_len = strlen(backing_file); |
| 774 |
} |
| 775 |
|
| 776 |
size_t header_size = sizeof(QCowHeader) + backing_file_len
|
| 777 |
+ backing_fmt_len; |
| 778 |
|
| 779 |
if (header_size > s->cluster_size) {
|
| 780 |
return -ENOSPC;
|
| 781 |
} |
| 782 |
|
| 783 |
/* Rewrite backing file name and qcow2 extensions */
|
| 784 |
size_t ext_size = header_size - sizeof(QCowHeader);
|
| 785 |
uint8_t buf[ext_size]; |
| 786 |
size_t offset = 0;
|
| 787 |
size_t backing_file_offset = 0;
|
| 788 |
|
| 789 |
if (backing_file) {
|
| 790 |
if (backing_fmt) {
|
| 791 |
int padding = backing_fmt_len -
|
| 792 |
(sizeof(ext_backing_fmt) + strlen(backing_fmt));
|
| 793 |
|
| 794 |
memcpy(buf + offset, &ext_backing_fmt, sizeof(ext_backing_fmt));
|
| 795 |
offset += sizeof(ext_backing_fmt);
|
| 796 |
|
| 797 |
memcpy(buf + offset, backing_fmt, strlen(backing_fmt)); |
| 798 |
offset += strlen(backing_fmt); |
| 799 |
|
| 800 |
memset(buf + offset, 0, padding);
|
| 801 |
offset += padding; |
| 802 |
} |
| 803 |
|
| 804 |
memcpy(buf + offset, backing_file, backing_file_len); |
| 805 |
backing_file_offset = sizeof(QCowHeader) + offset;
|
| 806 |
} |
| 807 |
|
| 808 |
ret = bdrv_pwrite_sync(bs->file, sizeof(QCowHeader), buf, ext_size);
|
| 809 |
if (ret < 0) { |
| 810 |
goto fail;
|
| 811 |
} |
| 812 |
|
| 813 |
/* Update header fields */
|
| 814 |
uint64_t be_backing_file_offset = cpu_to_be64(backing_file_offset); |
| 815 |
uint32_t be_backing_file_size = cpu_to_be32(backing_file_len); |
| 816 |
|
| 817 |
ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, backing_file_offset), |
| 818 |
&be_backing_file_offset, sizeof(uint64_t));
|
| 819 |
if (ret < 0) { |
| 820 |
goto fail;
|
| 821 |
} |
| 822 |
|
| 823 |
ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, backing_file_size), |
| 824 |
&be_backing_file_size, sizeof(uint32_t));
|
| 825 |
if (ret < 0) { |
| 826 |
goto fail;
|
| 827 |
} |
| 828 |
|
| 829 |
ret = 0;
|
| 830 |
fail:
|
| 831 |
return ret;
|
| 832 |
} |
| 833 |
|
| 834 |
static int qcow2_change_backing_file(BlockDriverState *bs, |
| 835 |
const char *backing_file, const char *backing_fmt) |
| 836 |
{
|
| 837 |
return qcow2_update_ext_header(bs, backing_file, backing_fmt);
|
| 838 |
} |
| 839 |
|
| 840 |
static int preallocate(BlockDriverState *bs) |
| 841 |
{
|
| 842 |
uint64_t nb_sectors; |
| 843 |
uint64_t offset; |
| 844 |
int num;
|
| 845 |
int ret;
|
| 846 |
QCowL2Meta meta; |
| 847 |
|
| 848 |
nb_sectors = bdrv_getlength(bs) >> 9;
|
| 849 |
offset = 0;
|
| 850 |
QLIST_INIT(&meta.dependent_requests); |
| 851 |
meta.cluster_offset = 0;
|
| 852 |
|
| 853 |
while (nb_sectors) {
|
| 854 |
num = MIN(nb_sectors, INT_MAX >> 9);
|
| 855 |
ret = qcow2_alloc_cluster_offset(bs, offset, 0, num, &num, &meta);
|
| 856 |
if (ret < 0) { |
| 857 |
return ret;
|
| 858 |
} |
| 859 |
|
| 860 |
ret = qcow2_alloc_cluster_link_l2(bs, &meta); |
| 861 |
if (ret < 0) { |
| 862 |
qcow2_free_any_clusters(bs, meta.cluster_offset, meta.nb_clusters); |
| 863 |
return ret;
|
| 864 |
} |
| 865 |
|
| 866 |
/* There are no dependent requests, but we need to remove our request
|
| 867 |
* from the list of in-flight requests */
|
| 868 |
run_dependent_requests(&meta); |
| 869 |
|
| 870 |
/* TODO Preallocate data if requested */
|
| 871 |
|
| 872 |
nb_sectors -= num; |
| 873 |
offset += num << 9;
|
| 874 |
} |
| 875 |
|
| 876 |
/*
|
| 877 |
* It is expected that the image file is large enough to actually contain
|
| 878 |
* all of the allocated clusters (otherwise we get failing reads after
|
| 879 |
* EOF). Extend the image to the last allocated sector.
|
| 880 |
*/
|
| 881 |
if (meta.cluster_offset != 0) { |
| 882 |
uint8_t buf[512];
|
| 883 |
memset(buf, 0, 512); |
| 884 |
ret = bdrv_write(bs->file, (meta.cluster_offset >> 9) + num - 1, buf, 1); |
| 885 |
if (ret < 0) { |
| 886 |
return ret;
|
| 887 |
} |
| 888 |
} |
| 889 |
|
| 890 |
return 0; |
| 891 |
} |
| 892 |
|
| 893 |
static int qcow2_create2(const char *filename, int64_t total_size, |
| 894 |
const char *backing_file, const char *backing_format, |
| 895 |
int flags, size_t cluster_size, int prealloc, |
| 896 |
QEMUOptionParameter *options) |
| 897 |
{
|
| 898 |
/* Calulate cluster_bits */
|
| 899 |
int cluster_bits;
|
| 900 |
cluster_bits = ffs(cluster_size) - 1;
|
| 901 |
if (cluster_bits < MIN_CLUSTER_BITS || cluster_bits > MAX_CLUSTER_BITS ||
|
| 902 |
(1 << cluster_bits) != cluster_size)
|
| 903 |
{
|
| 904 |
error_report( |
| 905 |
"Cluster size must be a power of two between %d and %dk\n",
|
| 906 |
1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10)); |
| 907 |
return -EINVAL;
|
| 908 |
} |
| 909 |
|
| 910 |
/*
|
| 911 |
* Open the image file and write a minimal qcow2 header.
|
| 912 |
*
|
| 913 |
* We keep things simple and start with a zero-sized image. We also
|
| 914 |
* do without refcount blocks or a L1 table for now. We'll fix the
|
| 915 |
* inconsistency later.
|
| 916 |
*
|
| 917 |
* We do need a refcount table because growing the refcount table means
|
| 918 |
* allocating two new refcount blocks - the seconds of which would be at
|
| 919 |
* 2 GB for 64k clusters, and we don't want to have a 2 GB initial file
|
| 920 |
* size for any qcow2 image.
|
| 921 |
*/
|
| 922 |
BlockDriverState* bs; |
| 923 |
QCowHeader header; |
| 924 |
uint8_t* refcount_table; |
| 925 |
int ret;
|
| 926 |
|
| 927 |
ret = bdrv_create_file(filename, options); |
| 928 |
if (ret < 0) { |
| 929 |
return ret;
|
| 930 |
} |
| 931 |
|
| 932 |
ret = bdrv_file_open(&bs, filename, BDRV_O_RDWR); |
| 933 |
if (ret < 0) { |
| 934 |
return ret;
|
| 935 |
} |
| 936 |
|
| 937 |
/* Write the header */
|
| 938 |
memset(&header, 0, sizeof(header)); |
| 939 |
header.magic = cpu_to_be32(QCOW_MAGIC); |
| 940 |
header.version = cpu_to_be32(QCOW_VERSION); |
| 941 |
header.cluster_bits = cpu_to_be32(cluster_bits); |
| 942 |
header.size = cpu_to_be64(0);
|
| 943 |
header.l1_table_offset = cpu_to_be64(0);
|
| 944 |
header.l1_size = cpu_to_be32(0);
|
| 945 |
header.refcount_table_offset = cpu_to_be64(cluster_size); |
| 946 |
header.refcount_table_clusters = cpu_to_be32(1);
|
| 947 |
|
| 948 |
if (flags & BLOCK_FLAG_ENCRYPT) {
|
| 949 |
header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES); |
| 950 |
} else {
|
| 951 |
header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); |
| 952 |
} |
| 953 |
|
| 954 |
ret = bdrv_pwrite(bs, 0, &header, sizeof(header)); |
| 955 |
if (ret < 0) { |
| 956 |
goto out;
|
| 957 |
} |
| 958 |
|
| 959 |
/* Write an empty refcount table */
|
| 960 |
refcount_table = qemu_mallocz(cluster_size); |
| 961 |
ret = bdrv_pwrite(bs, cluster_size, refcount_table, cluster_size); |
| 962 |
qemu_free(refcount_table); |
| 963 |
|
| 964 |
if (ret < 0) { |
| 965 |
goto out;
|
| 966 |
} |
| 967 |
|
| 968 |
bdrv_close(bs); |
| 969 |
|
| 970 |
/*
|
| 971 |
* And now open the image and make it consistent first (i.e. increase the
|
| 972 |
* refcount of the cluster that is occupied by the header and the refcount
|
| 973 |
* table)
|
| 974 |
*/
|
| 975 |
BlockDriver* drv = bdrv_find_format("qcow2");
|
| 976 |
assert(drv != NULL);
|
| 977 |
ret = bdrv_open(bs, filename, |
| 978 |
BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_NO_FLUSH, drv); |
| 979 |
if (ret < 0) { |
| 980 |
goto out;
|
| 981 |
} |
| 982 |
|
| 983 |
ret = qcow2_alloc_clusters(bs, 2 * cluster_size);
|
| 984 |
if (ret < 0) { |
| 985 |
goto out;
|
| 986 |
|
| 987 |
} else if (ret != 0) { |
| 988 |
error_report("Huh, first cluster in empty image is already in use?");
|
| 989 |
abort(); |
| 990 |
} |
| 991 |
|
| 992 |
/* Okay, now that we have a valid image, let's give it the right size */
|
| 993 |
ret = bdrv_truncate(bs, total_size * BDRV_SECTOR_SIZE); |
| 994 |
if (ret < 0) { |
| 995 |
goto out;
|
| 996 |
} |
| 997 |
|
| 998 |
/* Want a backing file? There you go.*/
|
| 999 |
if (backing_file) {
|
| 1000 |
ret = bdrv_change_backing_file(bs, backing_file, backing_format); |
| 1001 |
if (ret < 0) { |
| 1002 |
goto out;
|
| 1003 |
} |
| 1004 |
} |
| 1005 |
|
| 1006 |
/* And if we're supposed to preallocate metadata, do that now */
|
| 1007 |
if (prealloc) {
|
| 1008 |
ret = preallocate(bs); |
| 1009 |
if (ret < 0) { |
| 1010 |
goto out;
|
| 1011 |
} |
| 1012 |
} |
| 1013 |
|
| 1014 |
ret = 0;
|
| 1015 |
out:
|
| 1016 |
bdrv_delete(bs); |
| 1017 |
return ret;
|
| 1018 |
} |
| 1019 |
|
| 1020 |
static int qcow2_create(const char *filename, QEMUOptionParameter *options) |
| 1021 |
{
|
| 1022 |
const char *backing_file = NULL; |
| 1023 |
const char *backing_fmt = NULL; |
| 1024 |
uint64_t sectors = 0;
|
| 1025 |
int flags = 0; |
| 1026 |
size_t cluster_size = 65536;
|
| 1027 |
int prealloc = 0; |
| 1028 |
|
| 1029 |
/* Read out options */
|
| 1030 |
while (options && options->name) {
|
| 1031 |
if (!strcmp(options->name, BLOCK_OPT_SIZE)) {
|
| 1032 |
sectors = options->value.n / 512;
|
| 1033 |
} else if (!strcmp(options->name, BLOCK_OPT_BACKING_FILE)) { |
| 1034 |
backing_file = options->value.s; |
| 1035 |
} else if (!strcmp(options->name, BLOCK_OPT_BACKING_FMT)) { |
| 1036 |
backing_fmt = options->value.s; |
| 1037 |
} else if (!strcmp(options->name, BLOCK_OPT_ENCRYPT)) { |
| 1038 |
flags |= options->value.n ? BLOCK_FLAG_ENCRYPT : 0;
|
| 1039 |
} else if (!strcmp(options->name, BLOCK_OPT_CLUSTER_SIZE)) { |
| 1040 |
if (options->value.n) {
|
| 1041 |
cluster_size = options->value.n; |
| 1042 |
} |
| 1043 |
} else if (!strcmp(options->name, BLOCK_OPT_PREALLOC)) { |
| 1044 |
if (!options->value.s || !strcmp(options->value.s, "off")) { |
| 1045 |
prealloc = 0;
|
| 1046 |
} else if (!strcmp(options->value.s, "metadata")) { |
| 1047 |
prealloc = 1;
|
| 1048 |
} else {
|
| 1049 |
fprintf(stderr, "Invalid preallocation mode: '%s'\n",
|
| 1050 |
options->value.s); |
| 1051 |
return -EINVAL;
|
| 1052 |
} |
| 1053 |
} |
| 1054 |
options++; |
| 1055 |
} |
| 1056 |
|
| 1057 |
if (backing_file && prealloc) {
|
| 1058 |
fprintf(stderr, "Backing file and preallocation cannot be used at "
|
| 1059 |
"the same time\n");
|
| 1060 |
return -EINVAL;
|
| 1061 |
} |
| 1062 |
|
| 1063 |
return qcow2_create2(filename, sectors, backing_file, backing_fmt, flags,
|
| 1064 |
cluster_size, prealloc, options); |
| 1065 |
} |
| 1066 |
|
| 1067 |
static int qcow2_make_empty(BlockDriverState *bs) |
| 1068 |
{
|
| 1069 |
#if 0
|
| 1070 |
/* XXX: not correct */
|
| 1071 |
BDRVQcowState *s = bs->opaque;
|
| 1072 |
uint32_t l1_length = s->l1_size * sizeof(uint64_t);
|
| 1073 |
int ret;
|
| 1074 |
|
| 1075 |
memset(s->l1_table, 0, l1_length);
|
| 1076 |
if (bdrv_pwrite(bs->file, s->l1_table_offset, s->l1_table, l1_length) < 0)
|
| 1077 |
return -1;
|
| 1078 |
ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length);
|
| 1079 |
if (ret < 0)
|
| 1080 |
return ret;
|
| 1081 |
|
| 1082 |
l2_cache_reset(bs);
|
| 1083 |
#endif
|
| 1084 |
return 0; |
| 1085 |
} |
| 1086 |
|
| 1087 |
static int qcow2_discard(BlockDriverState *bs, int64_t sector_num, |
| 1088 |
int nb_sectors)
|
| 1089 |
{
|
| 1090 |
return qcow2_discard_clusters(bs, sector_num << BDRV_SECTOR_BITS,
|
| 1091 |
nb_sectors); |
| 1092 |
} |
| 1093 |
|
| 1094 |
static int qcow2_truncate(BlockDriverState *bs, int64_t offset) |
| 1095 |
{
|
| 1096 |
BDRVQcowState *s = bs->opaque; |
| 1097 |
int ret, new_l1_size;
|
| 1098 |
|
| 1099 |
if (offset & 511) { |
| 1100 |
return -EINVAL;
|
| 1101 |
} |
| 1102 |
|
| 1103 |
/* cannot proceed if image has snapshots */
|
| 1104 |
if (s->nb_snapshots) {
|
| 1105 |
return -ENOTSUP;
|
| 1106 |
} |
| 1107 |
|
| 1108 |
/* shrinking is currently not supported */
|
| 1109 |
if (offset < bs->total_sectors * 512) { |
| 1110 |
return -ENOTSUP;
|
| 1111 |
} |
| 1112 |
|
| 1113 |
new_l1_size = size_to_l1(s, offset); |
| 1114 |
ret = qcow2_grow_l1_table(bs, new_l1_size, true);
|
| 1115 |
if (ret < 0) { |
| 1116 |
return ret;
|
| 1117 |
} |
| 1118 |
|
| 1119 |
/* write updated header.size */
|
| 1120 |
offset = cpu_to_be64(offset); |
| 1121 |
ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, size), |
| 1122 |
&offset, sizeof(uint64_t));
|
| 1123 |
if (ret < 0) { |
| 1124 |
return ret;
|
| 1125 |
} |
| 1126 |
|
| 1127 |
s->l1_vm_state_index = new_l1_size; |
| 1128 |
return 0; |
| 1129 |
} |
| 1130 |
|
| 1131 |
/* XXX: put compressed sectors first, then all the cluster aligned
|
| 1132 |
tables to avoid losing bytes in alignment */
|
| 1133 |
static int qcow2_write_compressed(BlockDriverState *bs, int64_t sector_num, |
| 1134 |
const uint8_t *buf, int nb_sectors) |
| 1135 |
{
|
| 1136 |
BDRVQcowState *s = bs->opaque; |
| 1137 |
z_stream strm; |
| 1138 |
int ret, out_len;
|
| 1139 |
uint8_t *out_buf; |
| 1140 |
uint64_t cluster_offset; |
| 1141 |
|
| 1142 |
if (nb_sectors == 0) { |
| 1143 |
/* align end of file to a sector boundary to ease reading with
|
| 1144 |
sector based I/Os */
|
| 1145 |
cluster_offset = bdrv_getlength(bs->file); |
| 1146 |
cluster_offset = (cluster_offset + 511) & ~511; |
| 1147 |
bdrv_truncate(bs->file, cluster_offset); |
| 1148 |
return 0; |
| 1149 |
} |
| 1150 |
|
| 1151 |
if (nb_sectors != s->cluster_sectors)
|
| 1152 |
return -EINVAL;
|
| 1153 |
|
| 1154 |
out_buf = qemu_malloc(s->cluster_size + (s->cluster_size / 1000) + 128); |
| 1155 |
|
| 1156 |
/* best compression, small window, no zlib header */
|
| 1157 |
memset(&strm, 0, sizeof(strm)); |
| 1158 |
ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, |
| 1159 |
Z_DEFLATED, -12,
|
| 1160 |
9, Z_DEFAULT_STRATEGY);
|
| 1161 |
if (ret != 0) { |
| 1162 |
qemu_free(out_buf); |
| 1163 |
return -1; |
| 1164 |
} |
| 1165 |
|
| 1166 |
strm.avail_in = s->cluster_size; |
| 1167 |
strm.next_in = (uint8_t *)buf; |
| 1168 |
strm.avail_out = s->cluster_size; |
| 1169 |
strm.next_out = out_buf; |
| 1170 |
|
| 1171 |
ret = deflate(&strm, Z_FINISH); |
| 1172 |
if (ret != Z_STREAM_END && ret != Z_OK) {
|
| 1173 |
qemu_free(out_buf); |
| 1174 |
deflateEnd(&strm); |
| 1175 |
return -1; |
| 1176 |
} |
| 1177 |
out_len = strm.next_out - out_buf; |
| 1178 |
|
| 1179 |
deflateEnd(&strm); |
| 1180 |
|
| 1181 |
if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
|
| 1182 |
/* could not compress: write normal cluster */
|
| 1183 |
bdrv_write(bs, sector_num, buf, s->cluster_sectors); |
| 1184 |
} else {
|
| 1185 |
cluster_offset = qcow2_alloc_compressed_cluster_offset(bs, |
| 1186 |
sector_num << 9, out_len);
|
| 1187 |
if (!cluster_offset)
|
| 1188 |
return -1; |
| 1189 |
cluster_offset &= s->cluster_offset_mask; |
| 1190 |
BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED); |
| 1191 |
if (bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len) != out_len) {
|
| 1192 |
qemu_free(out_buf); |
| 1193 |
return -1; |
| 1194 |
} |
| 1195 |
} |
| 1196 |
|
| 1197 |
qemu_free(out_buf); |
| 1198 |
return 0; |
| 1199 |
} |
| 1200 |
|
| 1201 |
static int qcow2_flush(BlockDriverState *bs) |
| 1202 |
{
|
| 1203 |
BDRVQcowState *s = bs->opaque; |
| 1204 |
int ret;
|
| 1205 |
|
| 1206 |
ret = qcow2_cache_flush(bs, s->l2_table_cache); |
| 1207 |
if (ret < 0) { |
| 1208 |
return ret;
|
| 1209 |
} |
| 1210 |
|
| 1211 |
ret = qcow2_cache_flush(bs, s->refcount_block_cache); |
| 1212 |
if (ret < 0) { |
| 1213 |
return ret;
|
| 1214 |
} |
| 1215 |
|
| 1216 |
return bdrv_flush(bs->file);
|
| 1217 |
} |
| 1218 |
|
| 1219 |
static BlockDriverAIOCB *qcow2_aio_flush(BlockDriverState *bs,
|
| 1220 |
BlockDriverCompletionFunc *cb, |
| 1221 |
void *opaque)
|
| 1222 |
{
|
| 1223 |
BDRVQcowState *s = bs->opaque; |
| 1224 |
int ret;
|
| 1225 |
|
| 1226 |
ret = qcow2_cache_flush(bs, s->l2_table_cache); |
| 1227 |
if (ret < 0) { |
| 1228 |
return NULL; |
| 1229 |
} |
| 1230 |
|
| 1231 |
ret = qcow2_cache_flush(bs, s->refcount_block_cache); |
| 1232 |
if (ret < 0) { |
| 1233 |
return NULL; |
| 1234 |
} |
| 1235 |
|
| 1236 |
return bdrv_aio_flush(bs->file, cb, opaque);
|
| 1237 |
} |
| 1238 |
|
| 1239 |
static int64_t qcow2_vm_state_offset(BDRVQcowState *s)
|
| 1240 |
{
|
| 1241 |
return (int64_t)s->l1_vm_state_index << (s->cluster_bits + s->l2_bits);
|
| 1242 |
} |
| 1243 |
|
| 1244 |
static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) |
| 1245 |
{
|
| 1246 |
BDRVQcowState *s = bs->opaque; |
| 1247 |
bdi->cluster_size = s->cluster_size; |
| 1248 |
bdi->vm_state_offset = qcow2_vm_state_offset(s); |
| 1249 |
return 0; |
| 1250 |
} |
| 1251 |
|
| 1252 |
|
| 1253 |
static int qcow2_check(BlockDriverState *bs, BdrvCheckResult *result) |
| 1254 |
{
|
| 1255 |
return qcow2_check_refcounts(bs, result);
|
| 1256 |
} |
| 1257 |
|
| 1258 |
#if 0
|
| 1259 |
static void dump_refcounts(BlockDriverState *bs)
|
| 1260 |
{
|
| 1261 |
BDRVQcowState *s = bs->opaque;
|
| 1262 |
int64_t nb_clusters, k, k1, size;
|
| 1263 |
int refcount;
|
| 1264 |
|
| 1265 |
size = bdrv_getlength(bs->file);
|
| 1266 |
nb_clusters = size_to_clusters(s, size);
|
| 1267 |
for(k = 0; k < nb_clusters;) {
|
| 1268 |
k1 = k;
|
| 1269 |
refcount = get_refcount(bs, k);
|
| 1270 |
k++;
|
| 1271 |
while (k < nb_clusters && get_refcount(bs, k) == refcount)
|
| 1272 |
k++;
|
| 1273 |
printf("%" PRId64 ": refcount=%d nb=%" PRId64 "\n", k, refcount,
|
| 1274 |
k - k1);
|
| 1275 |
}
|
| 1276 |
}
|
| 1277 |
#endif
|
| 1278 |
|
| 1279 |
static int qcow2_save_vmstate(BlockDriverState *bs, const uint8_t *buf, |
| 1280 |
int64_t pos, int size)
|
| 1281 |
{
|
| 1282 |
BDRVQcowState *s = bs->opaque; |
| 1283 |
int growable = bs->growable;
|
| 1284 |
int ret;
|
| 1285 |
|
| 1286 |
BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE); |
| 1287 |
bs->growable = 1;
|
| 1288 |
ret = bdrv_pwrite(bs, qcow2_vm_state_offset(s) + pos, buf, size); |
| 1289 |
bs->growable = growable; |
| 1290 |
|
| 1291 |
return ret;
|
| 1292 |
} |
| 1293 |
|
| 1294 |
static int qcow2_load_vmstate(BlockDriverState *bs, uint8_t *buf, |
| 1295 |
int64_t pos, int size)
|
| 1296 |
{
|
| 1297 |
BDRVQcowState *s = bs->opaque; |
| 1298 |
int growable = bs->growable;
|
| 1299 |
int ret;
|
| 1300 |
|
| 1301 |
BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD); |
| 1302 |
bs->growable = 1;
|
| 1303 |
ret = bdrv_pread(bs, qcow2_vm_state_offset(s) + pos, buf, size); |
| 1304 |
bs->growable = growable; |
| 1305 |
|
| 1306 |
return ret;
|
| 1307 |
} |
| 1308 |
|
| 1309 |
static QEMUOptionParameter qcow2_create_options[] = {
|
| 1310 |
{
|
| 1311 |
.name = BLOCK_OPT_SIZE, |
| 1312 |
.type = OPT_SIZE, |
| 1313 |
.help = "Virtual disk size"
|
| 1314 |
}, |
| 1315 |
{
|
| 1316 |
.name = BLOCK_OPT_BACKING_FILE, |
| 1317 |
.type = OPT_STRING, |
| 1318 |
.help = "File name of a base image"
|
| 1319 |
}, |
| 1320 |
{
|
| 1321 |
.name = BLOCK_OPT_BACKING_FMT, |
| 1322 |
.type = OPT_STRING, |
| 1323 |
.help = "Image format of the base image"
|
| 1324 |
}, |
| 1325 |
{
|
| 1326 |
.name = BLOCK_OPT_ENCRYPT, |
| 1327 |
.type = OPT_FLAG, |
| 1328 |
.help = "Encrypt the image"
|
| 1329 |
}, |
| 1330 |
{
|
| 1331 |
.name = BLOCK_OPT_CLUSTER_SIZE, |
| 1332 |
.type = OPT_SIZE, |
| 1333 |
.help = "qcow2 cluster size"
|
| 1334 |
}, |
| 1335 |
{
|
| 1336 |
.name = BLOCK_OPT_PREALLOC, |
| 1337 |
.type = OPT_STRING, |
| 1338 |
.help = "Preallocation mode (allowed values: off, metadata)"
|
| 1339 |
}, |
| 1340 |
{ NULL }
|
| 1341 |
}; |
| 1342 |
|
| 1343 |
static BlockDriver bdrv_qcow2 = {
|
| 1344 |
.format_name = "qcow2",
|
| 1345 |
.instance_size = sizeof(BDRVQcowState),
|
| 1346 |
.bdrv_probe = qcow2_probe, |
| 1347 |
.bdrv_open = qcow2_open, |
| 1348 |
.bdrv_close = qcow2_close, |
| 1349 |
.bdrv_create = qcow2_create, |
| 1350 |
.bdrv_flush = qcow2_flush, |
| 1351 |
.bdrv_is_allocated = qcow2_is_allocated, |
| 1352 |
.bdrv_set_key = qcow2_set_key, |
| 1353 |
.bdrv_make_empty = qcow2_make_empty, |
| 1354 |
|
| 1355 |
.bdrv_aio_readv = qcow2_aio_readv, |
| 1356 |
.bdrv_aio_writev = qcow2_aio_writev, |
| 1357 |
.bdrv_aio_flush = qcow2_aio_flush, |
| 1358 |
|
| 1359 |
.bdrv_discard = qcow2_discard, |
| 1360 |
.bdrv_truncate = qcow2_truncate, |
| 1361 |
.bdrv_write_compressed = qcow2_write_compressed, |
| 1362 |
|
| 1363 |
.bdrv_snapshot_create = qcow2_snapshot_create, |
| 1364 |
.bdrv_snapshot_goto = qcow2_snapshot_goto, |
| 1365 |
.bdrv_snapshot_delete = qcow2_snapshot_delete, |
| 1366 |
.bdrv_snapshot_list = qcow2_snapshot_list, |
| 1367 |
.bdrv_snapshot_load_tmp = qcow2_snapshot_load_tmp, |
| 1368 |
.bdrv_get_info = qcow2_get_info, |
| 1369 |
|
| 1370 |
.bdrv_save_vmstate = qcow2_save_vmstate, |
| 1371 |
.bdrv_load_vmstate = qcow2_load_vmstate, |
| 1372 |
|
| 1373 |
.bdrv_change_backing_file = qcow2_change_backing_file, |
| 1374 |
|
| 1375 |
.create_options = qcow2_create_options, |
| 1376 |
.bdrv_check = qcow2_check, |
| 1377 |
}; |
| 1378 |
|
| 1379 |
static void bdrv_qcow2_init(void) |
| 1380 |
{
|
| 1381 |
bdrv_register(&bdrv_qcow2); |
| 1382 |
} |
| 1383 |
|
| 1384 |
block_init(bdrv_qcow2_init); |