summaryrefslogtreecommitdiff
path: root/block/qcow2-threads.c
blob: 1914baf456c71cb5caef3ca85c1ded57d837251b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
/*
 * Threaded data processing for Qcow2: compression, encryption
 *
 * Copyright (c) 2004-2006 Fabrice Bellard
 * Copyright (c) 2018 Virtuozzo International GmbH. All rights reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#include "qemu/osdep.h"

#define ZLIB_CONST
#include <zlib.h>

#ifdef CONFIG_ZSTD
#include <zstd.h>
#include <zstd_errors.h>
#endif

#include "qcow2.h"
#include "block/thread-pool.h"
#include "crypto.h"

static int coroutine_fn
qcow2_co_process(BlockDriverState *bs, ThreadPoolFunc *func, void *arg)
{
    int ret;
    BDRVQcow2State *s = bs->opaque;
    ThreadPool *pool = aio_get_thread_pool(bdrv_get_aio_context(bs));

    qemu_co_mutex_lock(&s->lock);
    while (s->nb_threads >= QCOW2_MAX_THREADS) {
        qemu_co_queue_wait(&s->thread_task_queue, &s->lock);
    }
    s->nb_threads++;
    qemu_co_mutex_unlock(&s->lock);

    ret = thread_pool_submit_co(pool, func, arg);

    qemu_co_mutex_lock(&s->lock);
    s->nb_threads--;
    qemu_co_queue_next(&s->thread_task_queue);
    qemu_co_mutex_unlock(&s->lock);

    return ret;
}


/*
 * Compression
 */

typedef ssize_t (*Qcow2CompressFunc)(void *dest, size_t dest_size,
                                     const void *src, size_t src_size);
typedef struct Qcow2CompressData {
    void *dest;
    size_t dest_size;
    const void *src;
    size_t src_size;
    ssize_t ret;

    Qcow2CompressFunc func;
} Qcow2CompressData;

/*
 * qcow2_zlib_compress()
 *
 * Compress @src_size bytes of data using zlib compression method
 *
 * @dest - destination buffer, @dest_size bytes
 * @src - source buffer, @src_size bytes
 *
 * Returns: compressed size on success
 *          -ENOMEM destination buffer is not enough to store compressed data
 *          -EIO    on any other error
 */
static ssize_t qcow2_zlib_compress(void *dest, size_t dest_size,
                                   const void *src, size_t src_size)
{
    ssize_t ret;
    z_stream strm;

    /* best compression, small window, no zlib header */
    memset(&strm, 0, sizeof(strm));
    ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, Z_DEFLATED,
                       -12, 9, Z_DEFAULT_STRATEGY);
    if (ret != Z_OK) {
        return -EIO;
    }

    /*
     * strm.next_in is not const in old zlib versions, such as those used on
     * OpenBSD/NetBSD, so cast the const away
     */
    strm.avail_in = src_size;
    strm.next_in = (void *) src;
    strm.avail_out = dest_size;
    strm.next_out = dest;

    ret = deflate(&strm, Z_FINISH);
    if (ret == Z_STREAM_END) {
        ret = dest_size - strm.avail_out;
    } else {
        ret = (ret == Z_OK ? -ENOMEM : -EIO);
    }

    deflateEnd(&strm);

    return ret;
}

/*
 * qcow2_zlib_decompress()
 *
 * Decompress some data (not more than @src_size bytes) to produce exactly
 * @dest_size bytes using zlib compression method
 *
 * @dest - destination buffer, @dest_size bytes
 * @src - source buffer, @src_size bytes
 *
 * Returns: 0 on success
 *          -EIO on fail
 */
static ssize_t qcow2_zlib_decompress(void *dest, size_t dest_size,
                                     const void *src, size_t src_size)
{
    int ret;
    z_stream strm;

    memset(&strm, 0, sizeof(strm));
    strm.avail_in = src_size;
    strm.next_in = (void *) src;
    strm.avail_out = dest_size;
    strm.next_out = dest;

    ret = inflateInit2(&strm, -12);
    if (ret != Z_OK) {
        return -EIO;
    }

    ret = inflate(&strm, Z_FINISH);
    if ((ret == Z_STREAM_END || ret == Z_BUF_ERROR) && strm.avail_out == 0) {
        /*
         * We approve Z_BUF_ERROR because we need @dest buffer to be filled, but
         * @src buffer may be processed partly (because in qcow2 we know size of
         * compressed data with precision of one sector)
         */
        ret = 0;
    } else {
        ret = -EIO;
    }

    inflateEnd(&strm);

    return ret;
}

#ifdef CONFIG_ZSTD

/*
 * qcow2_zstd_compress()
 *
 * Compress @src_size bytes of data using zstd compression method
 *
 * @dest - destination buffer, @dest_size bytes
 * @src - source buffer, @src_size bytes
 *
 * Returns: compressed size on success
 *          -ENOMEM destination buffer is not enough to store compressed data
 *          -EIO    on any other error
 */
static ssize_t qcow2_zstd_compress(void *dest, size_t dest_size,
                                   const void *src, size_t src_size)
{
    ssize_t ret;
    size_t zstd_ret;
    ZSTD_outBuffer output = {
        .dst = dest,
        .size = dest_size,
        .pos = 0
    };
    ZSTD_inBuffer input = {
        .src = src,
        .size = src_size,
        .pos = 0
    };
    ZSTD_CCtx *cctx = ZSTD_createCCtx();

    if (!cctx) {
        return -EIO;
    }
    /*
     * Use the zstd streamed interface for symmetry with decompression,
     * where streaming is essential since we don't record the exact
     * compressed size.
     *
     * ZSTD_compressStream2() tries to compress everything it could
     * with a single call. Although, ZSTD docs says that:
     * "You must continue calling ZSTD_compressStream2() with ZSTD_e_end
     * until it returns 0, at which point you are free to start a new frame",
     * in out tests we saw the only case when it returned with >0 -
     * when the output buffer was too small. In that case,
     * ZSTD_compressStream2() expects a bigger buffer on the next call.
     * We can't provide a bigger buffer because we are limited with dest_size
     * which we pass to the ZSTD_compressStream2() at once.
     * So, we don't need any loops and just abort the compression when we
     * don't get 0 result on the first call.
     */
    zstd_ret = ZSTD_compressStream2(cctx, &output, &input, ZSTD_e_end);

    if (zstd_ret) {
        if (zstd_ret > output.size - output.pos) {
            ret = -ENOMEM;
        } else {
            ret = -EIO;
        }
        goto out;
    }

    /* make sure that zstd didn't overflow the dest buffer */
    assert(output.pos <= dest_size);
    ret = output.pos;
out:
    ZSTD_freeCCtx(cctx);
    return ret;
}

/*
 * qcow2_zstd_decompress()
 *
 * Decompress some data (not more than @src_size bytes) to produce exactly
 * @dest_size bytes using zstd compression method
 *
 * @dest - destination buffer, @dest_size bytes
 * @src - source buffer, @src_size bytes
 *
 * Returns: 0 on success
 *          -EIO on any error
 */
static ssize_t qcow2_zstd_decompress(void *dest, size_t dest_size,
                                     const void *src, size_t src_size)
{
    size_t zstd_ret = 0;
    ssize_t ret = 0;
    ZSTD_outBuffer output = {
        .dst = dest,
        .size = dest_size,
        .pos = 0
    };
    ZSTD_inBuffer input = {
        .src = src,
        .size = src_size,
        .pos = 0
    };
    ZSTD_DCtx *dctx = ZSTD_createDCtx();

    if (!dctx) {
        return -EIO;
    }

    /*
     * The compressed stream from the input buffer may consist of more
     * than one zstd frame. So we iterate until we get a fully
     * uncompressed cluster.
     * From zstd docs related to ZSTD_decompressStream:
     * "return : 0 when a frame is completely decoded and fully flushed"
     * We suppose that this means: each time ZSTD_decompressStream reads
     * only ONE full frame and returns 0 if and only if that frame
     * is completely decoded and flushed. Only after returning 0,
     * ZSTD_decompressStream reads another ONE full frame.
     */
    while (output.pos < output.size) {
        size_t last_in_pos = input.pos;
        size_t last_out_pos = output.pos;
        zstd_ret = ZSTD_decompressStream(dctx, &output, &input);

        if (ZSTD_isError(zstd_ret)) {
            ret = -EIO;
            break;
        }

        /*
         * The ZSTD manual is vague about what to do if it reads
         * the buffer partially, and we don't want to get stuck
         * in an infinite loop where ZSTD_decompressStream
         * returns > 0 waiting for another input chunk. So, we add
         * a check which ensures that the loop makes some progress
         * on each step.
         */
        if (last_in_pos >= input.pos &&
            last_out_pos >= output.pos) {
            ret = -EIO;
            break;
        }
    }
    /*
     * Make sure that we have the frame fully flushed here
     * if not, we somehow managed to get uncompressed cluster
     * greater then the cluster size, possibly because of its
     * damage.
     */
    if (zstd_ret > 0) {
        ret = -EIO;
    }

    ZSTD_freeDCtx(dctx);
    assert(ret == 0 || ret == -EIO);
    return ret;
}
#endif

static int qcow2_compress_pool_func(void *opaque)
{
    Qcow2CompressData *data = opaque;

    data->ret = data->func(data->dest, data->dest_size,
                           data->src, data->src_size);

    return 0;
}

static ssize_t coroutine_fn
qcow2_co_do_compress(BlockDriverState *bs, void *dest, size_t dest_size,
                     const void *src, size_t src_size, Qcow2CompressFunc func)
{
    Qcow2CompressData arg = {
        .dest = dest,
        .dest_size = dest_size,
        .src = src,
        .src_size = src_size,
        .func = func,
    };

    qcow2_co_process(bs, qcow2_compress_pool_func, &arg);

    return arg.ret;
}

/*
 * qcow2_co_compress()
 *
 * Compress @src_size bytes of data using the compression
 * method defined by the image compression type
 *
 * @dest - destination buffer, @dest_size bytes
 * @src - source buffer, @src_size bytes
 *
 * Returns: compressed size on success
 *          a negative error code on failure
 */
ssize_t coroutine_fn
qcow2_co_compress(BlockDriverState *bs, void *dest, size_t dest_size,
                  const void *src, size_t src_size)
{
    BDRVQcow2State *s = bs->opaque;
    Qcow2CompressFunc fn;

    switch (s->compression_type) {
    case QCOW2_COMPRESSION_TYPE_ZLIB:
        fn = qcow2_zlib_compress;
        break;

#ifdef CONFIG_ZSTD
    case QCOW2_COMPRESSION_TYPE_ZSTD:
        fn = qcow2_zstd_compress;
        break;
#endif
    default:
        abort();
    }

    return qcow2_co_do_compress(bs, dest, dest_size, src, src_size, fn);
}

/*
 * qcow2_co_decompress()
 *
 * Decompress some data (not more than @src_size bytes) to produce exactly
 * @dest_size bytes using the compression method defined by the image
 * compression type
 *
 * @dest - destination buffer, @dest_size bytes
 * @src - source buffer, @src_size bytes
 *
 * Returns: 0 on success
 *          a negative error code on failure
 */
ssize_t coroutine_fn
qcow2_co_decompress(BlockDriverState *bs, void *dest, size_t dest_size,
                    const void *src, size_t src_size)
{
    BDRVQcow2State *s = bs->opaque;
    Qcow2CompressFunc fn;

    switch (s->compression_type) {
    case QCOW2_COMPRESSION_TYPE_ZLIB:
        fn = qcow2_zlib_decompress;
        break;

#ifdef CONFIG_ZSTD
    case QCOW2_COMPRESSION_TYPE_ZSTD:
        fn = qcow2_zstd_decompress;
        break;
#endif
    default:
        abort();
    }

    return qcow2_co_do_compress(bs, dest, dest_size, src, src_size, fn);
}


/*
 * Cryptography
 */

/*
 * Qcow2EncDecFunc: common prototype of qcrypto_block_encrypt() and
 * qcrypto_block_decrypt() functions.
 */
typedef int (*Qcow2EncDecFunc)(QCryptoBlock *block, uint64_t offset,
                               uint8_t *buf, size_t len, Error **errp);

typedef struct Qcow2EncDecData {
    QCryptoBlock *block;
    uint64_t offset;
    uint8_t *buf;
    size_t len;

    Qcow2EncDecFunc func;
} Qcow2EncDecData;

static int qcow2_encdec_pool_func(void *opaque)
{
    Qcow2EncDecData *data = opaque;

    return data->func(data->block, data->offset, data->buf, data->len, NULL);
}

static int coroutine_fn
qcow2_co_encdec(BlockDriverState *bs, uint64_t host_offset,
                uint64_t guest_offset, void *buf, size_t len,
                Qcow2EncDecFunc func)
{
    BDRVQcow2State *s = bs->opaque;
    Qcow2EncDecData arg = {
        .block = s->crypto,
        .offset = s->crypt_physical_offset ? host_offset : guest_offset,
        .buf = buf,
        .len = len,
        .func = func,
    };
    uint64_t sector_size;

    assert(s->crypto);

    sector_size = qcrypto_block_get_sector_size(s->crypto);
    assert(QEMU_IS_ALIGNED(guest_offset, sector_size));
    assert(QEMU_IS_ALIGNED(host_offset, sector_size));
    assert(QEMU_IS_ALIGNED(len, sector_size));

    return len == 0 ? 0 : qcow2_co_process(bs, qcow2_encdec_pool_func, &arg);
}

/*
 * qcow2_co_encrypt()
 *
 * Encrypts one or more contiguous aligned sectors
 *
 * @host_offset - underlying storage offset of the first sector of the
 * data to be encrypted
 *
 * @guest_offset - guest (virtual) offset of the first sector of the
 * data to be encrypted
 *
 * @buf - buffer with the data to encrypt, that after encryption
 *        will be written to the underlying storage device at
 *        @host_offset
 *
 * @len - length of the buffer (must be a multiple of the encryption
 *        sector size)
 *
 * Depending on the encryption method, @host_offset and/or @guest_offset
 * may be used for generating the initialization vector for
 * encryption.
 *
 * Note that while the whole range must be aligned on sectors, it
 * does not have to be aligned on clusters and can also cross cluster
 * boundaries
 */
int coroutine_fn
qcow2_co_encrypt(BlockDriverState *bs, uint64_t host_offset,
                 uint64_t guest_offset, void *buf, size_t len)
{
    return qcow2_co_encdec(bs, host_offset, guest_offset, buf, len,
                           qcrypto_block_encrypt);
}

/*
 * qcow2_co_decrypt()
 *
 * Decrypts one or more contiguous aligned sectors
 * Similar to qcow2_co_encrypt
 */
int coroutine_fn
qcow2_co_decrypt(BlockDriverState *bs, uint64_t host_offset,
                 uint64_t guest_offset, void *buf, size_t len)
{
    return qcow2_co_encdec(bs, host_offset, guest_offset, buf, len,
                           qcrypto_block_decrypt);
}