root / block / qcow2.c @ 5bc89ef6
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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" |
29 |
#include "block/qcow2.h" |
30 |
|
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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 QCOW_EXT_MAGIC_END 0 |
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#define QCOW_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA |
54 |
|
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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) |
58 |
{ |
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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; |
81 |
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; |
88 |
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("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; |
102 |
} |
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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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|
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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; |
119 |
} |
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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); |
128 |
break;
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129 |
|
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default:
|
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/* unknown magic -- just skip it */
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offset += ((ext.len + 7) & ~7); |
133 |
break;
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} |
135 |
} |
136 |
|
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return 0; |
138 |
} |
139 |
|
140 |
|
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static int qcow_open(BlockDriverState *bs, const char *filename, int flags) |
142 |
{ |
143 |
BDRVQcowState *s = bs->opaque; |
144 |
int len, i, shift, ret;
|
145 |
QCowHeader header; |
146 |
uint64_t ext_end; |
147 |
|
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ret = bdrv_file_open(&s->hd, filename, flags); |
149 |
if (ret < 0) |
150 |
return ret;
|
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if (bdrv_pread(s->hd, 0, &header, sizeof(header)) != sizeof(header)) |
152 |
goto fail;
|
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be32_to_cpus(&header.magic); |
154 |
be32_to_cpus(&header.version); |
155 |
be64_to_cpus(&header.backing_file_offset); |
156 |
be32_to_cpus(&header.backing_file_size); |
157 |
be64_to_cpus(&header.size); |
158 |
be32_to_cpus(&header.cluster_bits); |
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be32_to_cpus(&header.crypt_method); |
160 |
be64_to_cpus(&header.l1_table_offset); |
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be32_to_cpus(&header.l1_size); |
162 |
be64_to_cpus(&header.refcount_table_offset); |
163 |
be32_to_cpus(&header.refcount_table_clusters); |
164 |
be64_to_cpus(&header.snapshots_offset); |
165 |
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.size <= 1 || |
170 |
header.cluster_bits < MIN_CLUSTER_BITS || |
171 |
header.cluster_bits > MAX_CLUSTER_BITS) |
172 |
goto fail;
|
173 |
if (header.crypt_method > QCOW_CRYPT_AES)
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goto fail;
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175 |
s->crypt_method_header = header.crypt_method; |
176 |
if (s->crypt_method_header)
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bs->encrypted = 1;
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s->cluster_bits = header.cluster_bits; |
179 |
s->cluster_size = 1 << s->cluster_bits;
|
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s->cluster_sectors = 1 << (s->cluster_bits - 9); |
181 |
s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */ |
182 |
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)); |
185 |
s->csize_mask = (1 << (s->cluster_bits - 8)) - 1; |
186 |
s->cluster_offset_mask = (1LL << s->csize_shift) - 1; |
187 |
s->refcount_table_offset = header.refcount_table_offset; |
188 |
s->refcount_table_size = |
189 |
header.refcount_table_clusters << (s->cluster_bits - 3);
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|
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s->snapshots_offset = header.snapshots_offset; |
192 |
s->nb_snapshots = header.nb_snapshots; |
193 |
|
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/* read the level 1 table */
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s->l1_size = header.l1_size; |
196 |
shift = s->cluster_bits + s->l2_bits; |
197 |
s->l1_vm_state_index = (header.size + (1LL << shift) - 1) >> shift; |
198 |
/* the L1 table must contain at least enough entries to put
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header.size bytes */
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200 |
if (s->l1_size < s->l1_vm_state_index)
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goto fail;
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202 |
s->l1_table_offset = header.l1_table_offset; |
203 |
s->l1_table = qemu_mallocz( |
204 |
align_offset(s->l1_size * sizeof(uint64_t), 512)); |
205 |
if (bdrv_pread(s->hd, s->l1_table_offset, s->l1_table, s->l1_size * sizeof(uint64_t)) != |
206 |
s->l1_size * sizeof(uint64_t))
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207 |
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]); |
210 |
} |
211 |
/* 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); |
214 |
/* one more sector for decompressed data alignment */
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s->cluster_data = qemu_malloc(QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size |
216 |
+ 512);
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s->cluster_cache_offset = -1;
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218 |
|
219 |
if (qcow2_refcount_init(bs) < 0) |
220 |
goto fail;
|
221 |
|
222 |
/* read qcow2 extensions */
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223 |
if (header.backing_file_offset)
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224 |
ext_end = header.backing_file_offset; |
225 |
else
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226 |
ext_end = s->cluster_size; |
227 |
if (qcow_read_extensions(bs, sizeof(header), ext_end)) |
228 |
goto fail;
|
229 |
|
230 |
/* read the backing file name */
|
231 |
if (header.backing_file_offset != 0) { |
232 |
len = header.backing_file_size; |
233 |
if (len > 1023) |
234 |
len = 1023;
|
235 |
if (bdrv_pread(s->hd, header.backing_file_offset, bs->backing_file, len) != len)
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236 |
goto fail;
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237 |
bs->backing_file[len] = '\0';
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238 |
} |
239 |
if (qcow2_read_snapshots(bs) < 0) |
240 |
goto fail;
|
241 |
|
242 |
#ifdef DEBUG_ALLOC
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243 |
qcow2_check_refcounts(bs); |
244 |
#endif
|
245 |
return 0; |
246 |
|
247 |
fail:
|
248 |
qcow2_free_snapshots(bs); |
249 |
qcow2_refcount_close(bs); |
250 |
qemu_free(s->l1_table); |
251 |
qemu_free(s->l2_cache); |
252 |
qemu_free(s->cluster_cache); |
253 |
qemu_free(s->cluster_data); |
254 |
bdrv_delete(s->hd); |
255 |
return -1; |
256 |
} |
257 |
|
258 |
static int qcow_set_key(BlockDriverState *bs, const char *key) |
259 |
{ |
260 |
BDRVQcowState *s = bs->opaque; |
261 |
uint8_t keybuf[16];
|
262 |
int len, i;
|
263 |
|
264 |
memset(keybuf, 0, 16); |
265 |
len = strlen(key); |
266 |
if (len > 16) |
267 |
len = 16;
|
268 |
/* XXX: we could compress the chars to 7 bits to increase
|
269 |
entropy */
|
270 |
for(i = 0;i < len;i++) { |
271 |
keybuf[i] = key[i]; |
272 |
} |
273 |
s->crypt_method = s->crypt_method_header; |
274 |
|
275 |
if (AES_set_encrypt_key(keybuf, 128, &s->aes_encrypt_key) != 0) |
276 |
return -1; |
277 |
if (AES_set_decrypt_key(keybuf, 128, &s->aes_decrypt_key) != 0) |
278 |
return -1; |
279 |
#if 0
|
280 |
/* test */
|
281 |
{
|
282 |
uint8_t in[16];
|
283 |
uint8_t out[16];
|
284 |
uint8_t tmp[16];
|
285 |
for(i=0;i<16;i++)
|
286 |
in[i] = i;
|
287 |
AES_encrypt(in, tmp, &s->aes_encrypt_key);
|
288 |
AES_decrypt(tmp, out, &s->aes_decrypt_key);
|
289 |
for(i = 0; i < 16; i++)
|
290 |
printf(" %02x", tmp[i]);
|
291 |
printf("\n");
|
292 |
for(i = 0; i < 16; i++)
|
293 |
printf(" %02x", out[i]);
|
294 |
printf("\n");
|
295 |
}
|
296 |
#endif
|
297 |
return 0; |
298 |
} |
299 |
|
300 |
static int qcow_is_allocated(BlockDriverState *bs, int64_t sector_num, |
301 |
int nb_sectors, int *pnum) |
302 |
{ |
303 |
uint64_t cluster_offset; |
304 |
|
305 |
*pnum = nb_sectors; |
306 |
cluster_offset = qcow2_get_cluster_offset(bs, sector_num << 9, pnum);
|
307 |
|
308 |
return (cluster_offset != 0); |
309 |
} |
310 |
|
311 |
/* handle reading after the end of the backing file */
|
312 |
int qcow2_backing_read1(BlockDriverState *bs,
|
313 |
int64_t sector_num, uint8_t *buf, int nb_sectors)
|
314 |
{ |
315 |
int n1;
|
316 |
if ((sector_num + nb_sectors) <= bs->total_sectors)
|
317 |
return nb_sectors;
|
318 |
if (sector_num >= bs->total_sectors)
|
319 |
n1 = 0;
|
320 |
else
|
321 |
n1 = bs->total_sectors - sector_num; |
322 |
memset(buf + n1 * 512, 0, 512 * (nb_sectors - n1)); |
323 |
return n1;
|
324 |
} |
325 |
|
326 |
typedef struct QCowAIOCB { |
327 |
BlockDriverAIOCB common; |
328 |
int64_t sector_num; |
329 |
QEMUIOVector *qiov; |
330 |
uint8_t *buf; |
331 |
void *orig_buf;
|
332 |
int nb_sectors;
|
333 |
int n;
|
334 |
uint64_t cluster_offset; |
335 |
uint8_t *cluster_data; |
336 |
BlockDriverAIOCB *hd_aiocb; |
337 |
struct iovec hd_iov;
|
338 |
QEMUIOVector hd_qiov; |
339 |
QEMUBH *bh; |
340 |
QCowL2Meta l2meta; |
341 |
} QCowAIOCB; |
342 |
|
343 |
static void qcow_aio_cancel(BlockDriverAIOCB *blockacb) |
344 |
{ |
345 |
QCowAIOCB *acb = (QCowAIOCB *)blockacb; |
346 |
if (acb->hd_aiocb)
|
347 |
bdrv_aio_cancel(acb->hd_aiocb); |
348 |
qemu_aio_release(acb); |
349 |
} |
350 |
|
351 |
static AIOPool qcow_aio_pool = {
|
352 |
.aiocb_size = sizeof(QCowAIOCB),
|
353 |
.cancel = qcow_aio_cancel, |
354 |
}; |
355 |
|
356 |
static void qcow_aio_read_cb(void *opaque, int ret); |
357 |
static void qcow_aio_read_bh(void *opaque) |
358 |
{ |
359 |
QCowAIOCB *acb = opaque; |
360 |
qemu_bh_delete(acb->bh); |
361 |
acb->bh = NULL;
|
362 |
qcow_aio_read_cb(opaque, 0);
|
363 |
} |
364 |
|
365 |
static int qcow_schedule_bh(QEMUBHFunc *cb, QCowAIOCB *acb) |
366 |
{ |
367 |
if (acb->bh)
|
368 |
return -EIO;
|
369 |
|
370 |
acb->bh = qemu_bh_new(cb, acb); |
371 |
if (!acb->bh)
|
372 |
return -EIO;
|
373 |
|
374 |
qemu_bh_schedule(acb->bh); |
375 |
|
376 |
return 0; |
377 |
} |
378 |
|
379 |
static void qcow_aio_read_cb(void *opaque, int ret) |
380 |
{ |
381 |
QCowAIOCB *acb = opaque; |
382 |
BlockDriverState *bs = acb->common.bs; |
383 |
BDRVQcowState *s = bs->opaque; |
384 |
int index_in_cluster, n1;
|
385 |
|
386 |
acb->hd_aiocb = NULL;
|
387 |
if (ret < 0) |
388 |
goto done;
|
389 |
|
390 |
/* post process the read buffer */
|
391 |
if (!acb->cluster_offset) {
|
392 |
/* nothing to do */
|
393 |
} else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) { |
394 |
/* nothing to do */
|
395 |
} else {
|
396 |
if (s->crypt_method) {
|
397 |
qcow2_encrypt_sectors(s, acb->sector_num, acb->buf, acb->buf, |
398 |
acb->n, 0,
|
399 |
&s->aes_decrypt_key); |
400 |
} |
401 |
} |
402 |
|
403 |
acb->nb_sectors -= acb->n; |
404 |
acb->sector_num += acb->n; |
405 |
acb->buf += acb->n * 512;
|
406 |
|
407 |
if (acb->nb_sectors == 0) { |
408 |
/* request completed */
|
409 |
ret = 0;
|
410 |
goto done;
|
411 |
} |
412 |
|
413 |
/* prepare next AIO request */
|
414 |
acb->n = acb->nb_sectors; |
415 |
acb->cluster_offset = |
416 |
qcow2_get_cluster_offset(bs, acb->sector_num << 9, &acb->n);
|
417 |
index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
|
418 |
|
419 |
if (!acb->cluster_offset) {
|
420 |
if (bs->backing_hd) {
|
421 |
/* read from the base image */
|
422 |
n1 = qcow2_backing_read1(bs->backing_hd, acb->sector_num, |
423 |
acb->buf, acb->n); |
424 |
if (n1 > 0) { |
425 |
acb->hd_iov.iov_base = (void *)acb->buf;
|
426 |
acb->hd_iov.iov_len = acb->n * 512;
|
427 |
qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
|
428 |
acb->hd_aiocb = bdrv_aio_readv(bs->backing_hd, acb->sector_num, |
429 |
&acb->hd_qiov, acb->n, |
430 |
qcow_aio_read_cb, acb); |
431 |
if (acb->hd_aiocb == NULL) |
432 |
goto done;
|
433 |
} else {
|
434 |
ret = qcow_schedule_bh(qcow_aio_read_bh, acb); |
435 |
if (ret < 0) |
436 |
goto done;
|
437 |
} |
438 |
} else {
|
439 |
/* Note: in this case, no need to wait */
|
440 |
memset(acb->buf, 0, 512 * acb->n); |
441 |
ret = qcow_schedule_bh(qcow_aio_read_bh, acb); |
442 |
if (ret < 0) |
443 |
goto done;
|
444 |
} |
445 |
} else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) { |
446 |
/* add AIO support for compressed blocks ? */
|
447 |
if (qcow2_decompress_cluster(s, acb->cluster_offset) < 0) |
448 |
goto done;
|
449 |
memcpy(acb->buf, |
450 |
s->cluster_cache + index_in_cluster * 512, 512 * acb->n); |
451 |
ret = qcow_schedule_bh(qcow_aio_read_bh, acb); |
452 |
if (ret < 0) |
453 |
goto done;
|
454 |
} else {
|
455 |
if ((acb->cluster_offset & 511) != 0) { |
456 |
ret = -EIO; |
457 |
goto done;
|
458 |
} |
459 |
|
460 |
acb->hd_iov.iov_base = (void *)acb->buf;
|
461 |
acb->hd_iov.iov_len = acb->n * 512;
|
462 |
qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
|
463 |
acb->hd_aiocb = bdrv_aio_readv(s->hd, |
464 |
(acb->cluster_offset >> 9) + index_in_cluster,
|
465 |
&acb->hd_qiov, acb->n, qcow_aio_read_cb, acb); |
466 |
if (acb->hd_aiocb == NULL) |
467 |
goto done;
|
468 |
} |
469 |
|
470 |
return;
|
471 |
done:
|
472 |
if (acb->qiov->niov > 1) { |
473 |
qemu_iovec_from_buffer(acb->qiov, acb->orig_buf, acb->qiov->size); |
474 |
qemu_vfree(acb->orig_buf); |
475 |
} |
476 |
acb->common.cb(acb->common.opaque, ret); |
477 |
qemu_aio_release(acb); |
478 |
} |
479 |
|
480 |
static QCowAIOCB *qcow_aio_setup(BlockDriverState *bs,
|
481 |
int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
|
482 |
BlockDriverCompletionFunc *cb, void *opaque, int is_write) |
483 |
{ |
484 |
QCowAIOCB *acb; |
485 |
|
486 |
acb = qemu_aio_get(&qcow_aio_pool, bs, cb, opaque); |
487 |
if (!acb)
|
488 |
return NULL; |
489 |
acb->hd_aiocb = NULL;
|
490 |
acb->sector_num = sector_num; |
491 |
acb->qiov = qiov; |
492 |
if (qiov->niov > 1) { |
493 |
acb->buf = acb->orig_buf = qemu_blockalign(bs, qiov->size); |
494 |
if (is_write)
|
495 |
qemu_iovec_to_buffer(qiov, acb->buf); |
496 |
} else {
|
497 |
acb->buf = (uint8_t *)qiov->iov->iov_base; |
498 |
} |
499 |
acb->nb_sectors = nb_sectors; |
500 |
acb->n = 0;
|
501 |
acb->cluster_offset = 0;
|
502 |
acb->l2meta.nb_clusters = 0;
|
503 |
return acb;
|
504 |
} |
505 |
|
506 |
static BlockDriverAIOCB *qcow_aio_readv(BlockDriverState *bs,
|
507 |
int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
|
508 |
BlockDriverCompletionFunc *cb, void *opaque)
|
509 |
{ |
510 |
QCowAIOCB *acb; |
511 |
|
512 |
acb = qcow_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 0);
|
513 |
if (!acb)
|
514 |
return NULL; |
515 |
|
516 |
qcow_aio_read_cb(acb, 0);
|
517 |
return &acb->common;
|
518 |
} |
519 |
|
520 |
static void qcow_aio_write_cb(void *opaque, int ret) |
521 |
{ |
522 |
QCowAIOCB *acb = opaque; |
523 |
BlockDriverState *bs = acb->common.bs; |
524 |
BDRVQcowState *s = bs->opaque; |
525 |
int index_in_cluster;
|
526 |
const uint8_t *src_buf;
|
527 |
int n_end;
|
528 |
|
529 |
acb->hd_aiocb = NULL;
|
530 |
|
531 |
if (ret < 0) |
532 |
goto done;
|
533 |
|
534 |
if (qcow2_alloc_cluster_link_l2(bs, acb->cluster_offset, &acb->l2meta) < 0) { |
535 |
qcow2_free_any_clusters(bs, acb->cluster_offset, acb->l2meta.nb_clusters); |
536 |
goto done;
|
537 |
} |
538 |
|
539 |
acb->nb_sectors -= acb->n; |
540 |
acb->sector_num += acb->n; |
541 |
acb->buf += acb->n * 512;
|
542 |
|
543 |
if (acb->nb_sectors == 0) { |
544 |
/* request completed */
|
545 |
ret = 0;
|
546 |
goto done;
|
547 |
} |
548 |
|
549 |
index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
|
550 |
n_end = index_in_cluster + acb->nb_sectors; |
551 |
if (s->crypt_method &&
|
552 |
n_end > QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors) |
553 |
n_end = QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors; |
554 |
|
555 |
acb->cluster_offset = qcow2_alloc_cluster_offset(bs, acb->sector_num << 9,
|
556 |
index_in_cluster, |
557 |
n_end, &acb->n, &acb->l2meta); |
558 |
if (!acb->cluster_offset || (acb->cluster_offset & 511) != 0) { |
559 |
ret = -EIO; |
560 |
goto done;
|
561 |
} |
562 |
if (s->crypt_method) {
|
563 |
if (!acb->cluster_data) {
|
564 |
acb->cluster_data = qemu_mallocz(QCOW_MAX_CRYPT_CLUSTERS * |
565 |
s->cluster_size); |
566 |
} |
567 |
qcow2_encrypt_sectors(s, acb->sector_num, acb->cluster_data, acb->buf, |
568 |
acb->n, 1, &s->aes_encrypt_key);
|
569 |
src_buf = acb->cluster_data; |
570 |
} else {
|
571 |
src_buf = acb->buf; |
572 |
} |
573 |
acb->hd_iov.iov_base = (void *)src_buf;
|
574 |
acb->hd_iov.iov_len = acb->n * 512;
|
575 |
qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
|
576 |
acb->hd_aiocb = bdrv_aio_writev(s->hd, |
577 |
(acb->cluster_offset >> 9) + index_in_cluster,
|
578 |
&acb->hd_qiov, acb->n, |
579 |
qcow_aio_write_cb, acb); |
580 |
if (acb->hd_aiocb == NULL) |
581 |
goto done;
|
582 |
|
583 |
return;
|
584 |
|
585 |
done:
|
586 |
if (acb->qiov->niov > 1) |
587 |
qemu_vfree(acb->orig_buf); |
588 |
acb->common.cb(acb->common.opaque, ret); |
589 |
qemu_aio_release(acb); |
590 |
} |
591 |
|
592 |
static BlockDriverAIOCB *qcow_aio_writev(BlockDriverState *bs,
|
593 |
int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
|
594 |
BlockDriverCompletionFunc *cb, void *opaque)
|
595 |
{ |
596 |
BDRVQcowState *s = bs->opaque; |
597 |
QCowAIOCB *acb; |
598 |
|
599 |
s->cluster_cache_offset = -1; /* disable compressed cache */ |
600 |
|
601 |
acb = qcow_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 1);
|
602 |
if (!acb)
|
603 |
return NULL; |
604 |
|
605 |
qcow_aio_write_cb(acb, 0);
|
606 |
return &acb->common;
|
607 |
} |
608 |
|
609 |
static void qcow_close(BlockDriverState *bs) |
610 |
{ |
611 |
BDRVQcowState *s = bs->opaque; |
612 |
qemu_free(s->l1_table); |
613 |
qemu_free(s->l2_cache); |
614 |
qemu_free(s->cluster_cache); |
615 |
qemu_free(s->cluster_data); |
616 |
qcow2_refcount_close(bs); |
617 |
bdrv_delete(s->hd); |
618 |
} |
619 |
|
620 |
static int get_bits_from_size(size_t size) |
621 |
{ |
622 |
int res = 0; |
623 |
|
624 |
if (size == 0) { |
625 |
return -1; |
626 |
} |
627 |
|
628 |
while (size != 1) { |
629 |
/* Not a power of two */
|
630 |
if (size & 1) { |
631 |
return -1; |
632 |
} |
633 |
|
634 |
size >>= 1;
|
635 |
res++; |
636 |
} |
637 |
|
638 |
return res;
|
639 |
} |
640 |
|
641 |
|
642 |
static int preallocate(BlockDriverState *bs) |
643 |
{ |
644 |
BDRVQcowState *s = bs->opaque; |
645 |
uint64_t cluster_offset = 0;
|
646 |
uint64_t nb_sectors; |
647 |
uint64_t offset; |
648 |
int num;
|
649 |
QCowL2Meta meta; |
650 |
|
651 |
nb_sectors = bdrv_getlength(bs) >> 9;
|
652 |
offset = 0;
|
653 |
|
654 |
while (nb_sectors) {
|
655 |
num = MIN(nb_sectors, INT_MAX >> 9);
|
656 |
cluster_offset = qcow2_alloc_cluster_offset(bs, offset, 0, num, &num,
|
657 |
&meta); |
658 |
|
659 |
if (cluster_offset == 0) { |
660 |
return -1; |
661 |
} |
662 |
|
663 |
if (qcow2_alloc_cluster_link_l2(bs, cluster_offset, &meta) < 0) { |
664 |
qcow2_free_any_clusters(bs, cluster_offset, meta.nb_clusters); |
665 |
return -1; |
666 |
} |
667 |
|
668 |
/* TODO Preallocate data if requested */
|
669 |
|
670 |
nb_sectors -= num; |
671 |
offset += num << 9;
|
672 |
} |
673 |
|
674 |
/*
|
675 |
* It is expected that the image file is large enough to actually contain
|
676 |
* all of the allocated clusters (otherwise we get failing reads after
|
677 |
* EOF). Extend the image to the last allocated sector.
|
678 |
*/
|
679 |
if (cluster_offset != 0) { |
680 |
bdrv_truncate(s->hd, cluster_offset + (num << 9));
|
681 |
} |
682 |
|
683 |
return 0; |
684 |
} |
685 |
|
686 |
static int qcow_create2(const char *filename, int64_t total_size, |
687 |
const char *backing_file, const char *backing_format, |
688 |
int flags, size_t cluster_size, int prealloc) |
689 |
{ |
690 |
|
691 |
int fd, header_size, backing_filename_len, l1_size, i, shift, l2_bits;
|
692 |
int ref_clusters, backing_format_len = 0; |
693 |
QCowHeader header; |
694 |
uint64_t tmp, offset; |
695 |
QCowCreateState s1, *s = &s1; |
696 |
QCowExtension ext_bf = {0, 0}; |
697 |
|
698 |
|
699 |
memset(s, 0, sizeof(*s)); |
700 |
|
701 |
fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
|
702 |
if (fd < 0) |
703 |
return -1; |
704 |
memset(&header, 0, sizeof(header)); |
705 |
header.magic = cpu_to_be32(QCOW_MAGIC); |
706 |
header.version = cpu_to_be32(QCOW_VERSION); |
707 |
header.size = cpu_to_be64(total_size * 512);
|
708 |
header_size = sizeof(header);
|
709 |
backing_filename_len = 0;
|
710 |
if (backing_file) {
|
711 |
if (backing_format) {
|
712 |
ext_bf.magic = QCOW_EXT_MAGIC_BACKING_FORMAT; |
713 |
backing_format_len = strlen(backing_format); |
714 |
ext_bf.len = (backing_format_len + 7) & ~7; |
715 |
header_size += ((sizeof(ext_bf) + ext_bf.len + 7) & ~7); |
716 |
} |
717 |
header.backing_file_offset = cpu_to_be64(header_size); |
718 |
backing_filename_len = strlen(backing_file); |
719 |
header.backing_file_size = cpu_to_be32(backing_filename_len); |
720 |
header_size += backing_filename_len; |
721 |
} |
722 |
|
723 |
/* Cluster size */
|
724 |
s->cluster_bits = get_bits_from_size(cluster_size); |
725 |
if (s->cluster_bits < MIN_CLUSTER_BITS ||
|
726 |
s->cluster_bits > MAX_CLUSTER_BITS) |
727 |
{ |
728 |
fprintf(stderr, "Cluster size must be a power of two between "
|
729 |
"%d and %dk\n",
|
730 |
1 << MIN_CLUSTER_BITS,
|
731 |
1 << (MAX_CLUSTER_BITS - 10)); |
732 |
return -EINVAL;
|
733 |
} |
734 |
s->cluster_size = 1 << s->cluster_bits;
|
735 |
|
736 |
header.cluster_bits = cpu_to_be32(s->cluster_bits); |
737 |
header_size = (header_size + 7) & ~7; |
738 |
if (flags & BLOCK_FLAG_ENCRYPT) {
|
739 |
header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES); |
740 |
} else {
|
741 |
header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); |
742 |
} |
743 |
l2_bits = s->cluster_bits - 3;
|
744 |
shift = s->cluster_bits + l2_bits; |
745 |
l1_size = (((total_size * 512) + (1LL << shift) - 1) >> shift); |
746 |
offset = align_offset(header_size, s->cluster_size); |
747 |
s->l1_table_offset = offset; |
748 |
header.l1_table_offset = cpu_to_be64(s->l1_table_offset); |
749 |
header.l1_size = cpu_to_be32(l1_size); |
750 |
offset += align_offset(l1_size * sizeof(uint64_t), s->cluster_size);
|
751 |
|
752 |
s->refcount_table = qemu_mallocz(s->cluster_size); |
753 |
|
754 |
s->refcount_table_offset = offset; |
755 |
header.refcount_table_offset = cpu_to_be64(offset); |
756 |
header.refcount_table_clusters = cpu_to_be32(1);
|
757 |
offset += s->cluster_size; |
758 |
s->refcount_block_offset = offset; |
759 |
|
760 |
/* count how many refcount blocks needed */
|
761 |
tmp = offset >> s->cluster_bits; |
762 |
ref_clusters = (tmp >> (s->cluster_bits - REFCOUNT_SHIFT)) + 1;
|
763 |
for (i=0; i < ref_clusters; i++) { |
764 |
s->refcount_table[i] = cpu_to_be64(offset); |
765 |
offset += s->cluster_size; |
766 |
} |
767 |
|
768 |
s->refcount_block = qemu_mallocz(ref_clusters * s->cluster_size); |
769 |
|
770 |
/* update refcounts */
|
771 |
qcow2_create_refcount_update(s, 0, header_size);
|
772 |
qcow2_create_refcount_update(s, s->l1_table_offset, |
773 |
l1_size * sizeof(uint64_t));
|
774 |
qcow2_create_refcount_update(s, s->refcount_table_offset, s->cluster_size); |
775 |
qcow2_create_refcount_update(s, s->refcount_block_offset, |
776 |
ref_clusters * s->cluster_size); |
777 |
|
778 |
/* write all the data */
|
779 |
write(fd, &header, sizeof(header));
|
780 |
if (backing_file) {
|
781 |
if (backing_format_len) {
|
782 |
char zero[16]; |
783 |
int d = ext_bf.len - backing_format_len;
|
784 |
|
785 |
memset(zero, 0, sizeof(zero)); |
786 |
cpu_to_be32s(&ext_bf.magic); |
787 |
cpu_to_be32s(&ext_bf.len); |
788 |
write(fd, &ext_bf, sizeof(ext_bf));
|
789 |
write(fd, backing_format, backing_format_len); |
790 |
if (d>0) { |
791 |
write(fd, zero, d); |
792 |
} |
793 |
} |
794 |
write(fd, backing_file, backing_filename_len); |
795 |
} |
796 |
lseek(fd, s->l1_table_offset, SEEK_SET); |
797 |
tmp = 0;
|
798 |
for(i = 0;i < l1_size; i++) { |
799 |
write(fd, &tmp, sizeof(tmp));
|
800 |
} |
801 |
lseek(fd, s->refcount_table_offset, SEEK_SET); |
802 |
write(fd, s->refcount_table, s->cluster_size); |
803 |
|
804 |
lseek(fd, s->refcount_block_offset, SEEK_SET); |
805 |
write(fd, s->refcount_block, ref_clusters * s->cluster_size); |
806 |
|
807 |
qemu_free(s->refcount_table); |
808 |
qemu_free(s->refcount_block); |
809 |
close(fd); |
810 |
|
811 |
/* Preallocate metadata */
|
812 |
if (prealloc) {
|
813 |
BlockDriverState *bs; |
814 |
bs = bdrv_new("");
|
815 |
bdrv_open(bs, filename, BDRV_O_CACHE_WB); |
816 |
preallocate(bs); |
817 |
bdrv_close(bs); |
818 |
} |
819 |
|
820 |
return 0; |
821 |
} |
822 |
|
823 |
static int qcow_create(const char *filename, QEMUOptionParameter *options) |
824 |
{ |
825 |
const char *backing_file = NULL; |
826 |
const char *backing_fmt = NULL; |
827 |
uint64_t sectors = 0;
|
828 |
int flags = 0; |
829 |
size_t cluster_size = 65536;
|
830 |
int prealloc = 0; |
831 |
|
832 |
/* Read out options */
|
833 |
while (options && options->name) {
|
834 |
if (!strcmp(options->name, BLOCK_OPT_SIZE)) {
|
835 |
sectors = options->value.n / 512;
|
836 |
} else if (!strcmp(options->name, BLOCK_OPT_BACKING_FILE)) { |
837 |
backing_file = options->value.s; |
838 |
} else if (!strcmp(options->name, BLOCK_OPT_BACKING_FMT)) { |
839 |
backing_fmt = options->value.s; |
840 |
} else if (!strcmp(options->name, BLOCK_OPT_ENCRYPT)) { |
841 |
flags |= options->value.n ? BLOCK_FLAG_ENCRYPT : 0;
|
842 |
} else if (!strcmp(options->name, BLOCK_OPT_CLUSTER_SIZE)) { |
843 |
if (options->value.n) {
|
844 |
cluster_size = options->value.n; |
845 |
} |
846 |
} else if (!strcmp(options->name, BLOCK_OPT_PREALLOC)) { |
847 |
if (!options->value.s || !strcmp(options->value.s, "off")) { |
848 |
prealloc = 0;
|
849 |
} else if (!strcmp(options->value.s, "metadata")) { |
850 |
prealloc = 1;
|
851 |
} else {
|
852 |
fprintf(stderr, "Invalid preallocation mode: '%s'\n",
|
853 |
options->value.s); |
854 |
return -EINVAL;
|
855 |
} |
856 |
} |
857 |
options++; |
858 |
} |
859 |
|
860 |
if (backing_file && prealloc) {
|
861 |
fprintf(stderr, "Backing file and preallocation cannot be used at "
|
862 |
"the same time\n");
|
863 |
return -EINVAL;
|
864 |
} |
865 |
|
866 |
return qcow_create2(filename, sectors, backing_file, backing_fmt, flags,
|
867 |
cluster_size, prealloc); |
868 |
} |
869 |
|
870 |
static int qcow_make_empty(BlockDriverState *bs) |
871 |
{ |
872 |
#if 0
|
873 |
/* XXX: not correct */
|
874 |
BDRVQcowState *s = bs->opaque;
|
875 |
uint32_t l1_length = s->l1_size * sizeof(uint64_t);
|
876 |
int ret;
|
877 |
|
878 |
memset(s->l1_table, 0, l1_length);
|
879 |
if (bdrv_pwrite(s->hd, s->l1_table_offset, s->l1_table, l1_length) < 0)
|
880 |
return -1;
|
881 |
ret = bdrv_truncate(s->hd, s->l1_table_offset + l1_length);
|
882 |
if (ret < 0)
|
883 |
return ret;
|
884 |
|
885 |
l2_cache_reset(bs);
|
886 |
#endif
|
887 |
return 0; |
888 |
} |
889 |
|
890 |
/* XXX: put compressed sectors first, then all the cluster aligned
|
891 |
tables to avoid losing bytes in alignment */
|
892 |
static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num, |
893 |
const uint8_t *buf, int nb_sectors) |
894 |
{ |
895 |
BDRVQcowState *s = bs->opaque; |
896 |
z_stream strm; |
897 |
int ret, out_len;
|
898 |
uint8_t *out_buf; |
899 |
uint64_t cluster_offset; |
900 |
|
901 |
if (nb_sectors == 0) { |
902 |
/* align end of file to a sector boundary to ease reading with
|
903 |
sector based I/Os */
|
904 |
cluster_offset = bdrv_getlength(s->hd); |
905 |
cluster_offset = (cluster_offset + 511) & ~511; |
906 |
bdrv_truncate(s->hd, cluster_offset); |
907 |
return 0; |
908 |
} |
909 |
|
910 |
if (nb_sectors != s->cluster_sectors)
|
911 |
return -EINVAL;
|
912 |
|
913 |
out_buf = qemu_malloc(s->cluster_size + (s->cluster_size / 1000) + 128); |
914 |
|
915 |
/* best compression, small window, no zlib header */
|
916 |
memset(&strm, 0, sizeof(strm)); |
917 |
ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, |
918 |
Z_DEFLATED, -12,
|
919 |
9, Z_DEFAULT_STRATEGY);
|
920 |
if (ret != 0) { |
921 |
qemu_free(out_buf); |
922 |
return -1; |
923 |
} |
924 |
|
925 |
strm.avail_in = s->cluster_size; |
926 |
strm.next_in = (uint8_t *)buf; |
927 |
strm.avail_out = s->cluster_size; |
928 |
strm.next_out = out_buf; |
929 |
|
930 |
ret = deflate(&strm, Z_FINISH); |
931 |
if (ret != Z_STREAM_END && ret != Z_OK) {
|
932 |
qemu_free(out_buf); |
933 |
deflateEnd(&strm); |
934 |
return -1; |
935 |
} |
936 |
out_len = strm.next_out - out_buf; |
937 |
|
938 |
deflateEnd(&strm); |
939 |
|
940 |
if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
|
941 |
/* could not compress: write normal cluster */
|
942 |
bdrv_write(bs, sector_num, buf, s->cluster_sectors); |
943 |
} else {
|
944 |
cluster_offset = qcow2_alloc_compressed_cluster_offset(bs, |
945 |
sector_num << 9, out_len);
|
946 |
if (!cluster_offset)
|
947 |
return -1; |
948 |
cluster_offset &= s->cluster_offset_mask; |
949 |
if (bdrv_pwrite(s->hd, cluster_offset, out_buf, out_len) != out_len) {
|
950 |
qemu_free(out_buf); |
951 |
return -1; |
952 |
} |
953 |
} |
954 |
|
955 |
qemu_free(out_buf); |
956 |
return 0; |
957 |
} |
958 |
|
959 |
static void qcow_flush(BlockDriverState *bs) |
960 |
{ |
961 |
BDRVQcowState *s = bs->opaque; |
962 |
bdrv_flush(s->hd); |
963 |
} |
964 |
|
965 |
static int64_t qcow_vm_state_offset(BDRVQcowState *s)
|
966 |
{ |
967 |
return (int64_t)s->l1_vm_state_index << (s->cluster_bits + s->l2_bits);
|
968 |
} |
969 |
|
970 |
static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) |
971 |
{ |
972 |
BDRVQcowState *s = bs->opaque; |
973 |
bdi->cluster_size = s->cluster_size; |
974 |
bdi->vm_state_offset = qcow_vm_state_offset(s); |
975 |
return 0; |
976 |
} |
977 |
|
978 |
|
979 |
static int qcow_check(BlockDriverState *bs) |
980 |
{ |
981 |
return qcow2_check_refcounts(bs);
|
982 |
} |
983 |
|
984 |
#if 0
|
985 |
static void dump_refcounts(BlockDriverState *bs)
|
986 |
{
|
987 |
BDRVQcowState *s = bs->opaque;
|
988 |
int64_t nb_clusters, k, k1, size;
|
989 |
int refcount;
|
990 |
|
991 |
size = bdrv_getlength(s->hd);
|
992 |
nb_clusters = size_to_clusters(s, size);
|
993 |
for(k = 0; k < nb_clusters;) {
|
994 |
k1 = k;
|
995 |
refcount = get_refcount(bs, k);
|
996 |
k++;
|
997 |
while (k < nb_clusters && get_refcount(bs, k) == refcount)
|
998 |
k++;
|
999 |
printf("%lld: refcount=%d nb=%lld\n", k, refcount, k - k1);
|
1000 |
}
|
1001 |
}
|
1002 |
#endif
|
1003 |
|
1004 |
static int qcow_save_vmstate(BlockDriverState *bs, const uint8_t *buf, |
1005 |
int64_t pos, int size)
|
1006 |
{ |
1007 |
BDRVQcowState *s = bs->opaque; |
1008 |
int growable = bs->growable;
|
1009 |
|
1010 |
bs->growable = 1;
|
1011 |
bdrv_pwrite(bs, qcow_vm_state_offset(s) + pos, buf, size); |
1012 |
bs->growable = growable; |
1013 |
|
1014 |
return size;
|
1015 |
} |
1016 |
|
1017 |
static int qcow_load_vmstate(BlockDriverState *bs, uint8_t *buf, |
1018 |
int64_t pos, int size)
|
1019 |
{ |
1020 |
BDRVQcowState *s = bs->opaque; |
1021 |
int growable = bs->growable;
|
1022 |
int ret;
|
1023 |
|
1024 |
bs->growable = 1;
|
1025 |
ret = bdrv_pread(bs, qcow_vm_state_offset(s) + pos, buf, size); |
1026 |
bs->growable = growable; |
1027 |
|
1028 |
return ret;
|
1029 |
} |
1030 |
|
1031 |
static QEMUOptionParameter qcow_create_options[] = {
|
1032 |
{ |
1033 |
.name = BLOCK_OPT_SIZE, |
1034 |
.type = OPT_SIZE, |
1035 |
.help = "Virtual disk size"
|
1036 |
}, |
1037 |
{ |
1038 |
.name = BLOCK_OPT_BACKING_FILE, |
1039 |
.type = OPT_STRING, |
1040 |
.help = "File name of a base image"
|
1041 |
}, |
1042 |
{ |
1043 |
.name = BLOCK_OPT_BACKING_FMT, |
1044 |
.type = OPT_STRING, |
1045 |
.help = "Image format of the base image"
|
1046 |
}, |
1047 |
{ |
1048 |
.name = BLOCK_OPT_ENCRYPT, |
1049 |
.type = OPT_FLAG, |
1050 |
.help = "Encrypt the image"
|
1051 |
}, |
1052 |
{ |
1053 |
.name = BLOCK_OPT_CLUSTER_SIZE, |
1054 |
.type = OPT_SIZE, |
1055 |
.help = "qcow2 cluster size"
|
1056 |
}, |
1057 |
{ |
1058 |
.name = BLOCK_OPT_PREALLOC, |
1059 |
.type = OPT_STRING, |
1060 |
.help = "Preallocation mode (allowed values: off, metadata)"
|
1061 |
}, |
1062 |
{ NULL }
|
1063 |
}; |
1064 |
|
1065 |
static BlockDriver bdrv_qcow2 = {
|
1066 |
.format_name = "qcow2",
|
1067 |
.instance_size = sizeof(BDRVQcowState),
|
1068 |
.bdrv_probe = qcow_probe, |
1069 |
.bdrv_open = qcow_open, |
1070 |
.bdrv_close = qcow_close, |
1071 |
.bdrv_create = qcow_create, |
1072 |
.bdrv_flush = qcow_flush, |
1073 |
.bdrv_is_allocated = qcow_is_allocated, |
1074 |
.bdrv_set_key = qcow_set_key, |
1075 |
.bdrv_make_empty = qcow_make_empty, |
1076 |
|
1077 |
.bdrv_aio_readv = qcow_aio_readv, |
1078 |
.bdrv_aio_writev = qcow_aio_writev, |
1079 |
.bdrv_write_compressed = qcow_write_compressed, |
1080 |
|
1081 |
.bdrv_snapshot_create = qcow2_snapshot_create, |
1082 |
.bdrv_snapshot_goto = qcow2_snapshot_goto, |
1083 |
.bdrv_snapshot_delete = qcow2_snapshot_delete, |
1084 |
.bdrv_snapshot_list = qcow2_snapshot_list, |
1085 |
.bdrv_get_info = qcow_get_info, |
1086 |
|
1087 |
.bdrv_save_vmstate = qcow_save_vmstate, |
1088 |
.bdrv_load_vmstate = qcow_load_vmstate, |
1089 |
|
1090 |
.create_options = qcow_create_options, |
1091 |
.bdrv_check = qcow_check, |
1092 |
}; |
1093 |
|
1094 |
static void bdrv_qcow2_init(void) |
1095 |
{ |
1096 |
bdrv_register(&bdrv_qcow2); |
1097 |
} |
1098 |
|
1099 |
block_init(bdrv_qcow2_init); |