block/qcow2-threads.c

   1 /*
   2  * Threaded data processing for Qcow2: compression, encryption
   3  *
   4  * Copyright (c) 2004-2006 Fabrice Bellard
   5  * Copyright (c) 2018 Virtuozzo International GmbH. All rights reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a copy
   8  * of this software and associated documentation files (the "Software"), to deal
   9  * in the Software without restriction, including without limitation the rights
  10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11  * copies of the Software, and to permit persons to whom the Software is
  12  * furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in
  15  * all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  23  * THE SOFTWARE.
  24  */
  25
  26 #include "qemu/osdep.h"
  27
  28 #define ZLIB_CONST
  29 #include <zlib.h>
  30
  31 #include "qcow2.h"
  32 #include "block/thread-pool.h"
  33 #include "crypto.h"
  34
  35 static int coroutine_fn
  36 qcow2_co_process(BlockDriverState *bs, ThreadPoolFunc *func, void *arg)
  37 {
  38     int ret;
  39     BDRVQcow2State *s = bs->opaque;
  40     ThreadPool *pool = aio_get_thread_pool(bdrv_get_aio_context(bs));
  41
  42     qemu_co_mutex_lock(&s->lock);
  43     while (s->nb_threads >= QCOW2_MAX_THREADS) {
  44         qemu_co_queue_wait(&s->thread_task_queue, &s->lock);
  45     }
  46     s->nb_threads++;
  47     qemu_co_mutex_unlock(&s->lock);
  48
  49     ret = thread_pool_submit_co(pool, func, arg);
  50
  51     qemu_co_mutex_lock(&s->lock);
  52     s->nb_threads--;
  53     qemu_co_queue_next(&s->thread_task_queue);
  54     qemu_co_mutex_unlock(&s->lock);
  55
  56     return ret;
  57 }
  58
  59
  60 /*
  61  * Compression
  62  */
  63
  64 typedef ssize_t (*Qcow2CompressFunc)(void *dest, size_t dest_size,
  65                                      const void *src, size_t src_size);
  66 typedef struct Qcow2CompressData {
  67     void *dest;
  68     size_t dest_size;
  69     const void *src;
  70     size_t src_size;
  71     ssize_t ret;
  72
  73     Qcow2CompressFunc func;
  74 } Qcow2CompressData;
  75
  76 /*
  77  * qcow2_compress()
  78  *
  79  * @dest - destination buffer, @dest_size bytes
  80  * @src - source buffer, @src_size bytes
  81  *
  82  * Returns: compressed size on success
  83  *          -ENOMEM destination buffer is not enough to store compressed data
  84  *          -EIO    on any other error
  85  */
  86 static ssize_t qcow2_compress(void *dest, size_t dest_size,
  87                               const void *src, size_t src_size)
  88 {
  89     ssize_t ret;
  90     z_stream strm;
  91
  92     /* best compression, small window, no zlib header */
  93     memset(&strm, 0, sizeof(strm));
  94     ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, Z_DEFLATED,
  95                        -12, 9, Z_DEFAULT_STRATEGY);
  96     if (ret != Z_OK) {
  97         return -EIO;
  98     }
  99
 100     /*
 101      * strm.next_in is not const in old zlib versions, such as those used on
 102      * OpenBSD/NetBSD, so cast the const away
 103      */
 104     strm.avail_in = src_size;
 105     strm.next_in = (void *) src;
 106     strm.avail_out = dest_size;
 107     strm.next_out = dest;
 108
 109     ret = deflate(&strm, Z_FINISH);
 110     if (ret == Z_STREAM_END) {
 111         ret = dest_size - strm.avail_out;
 112     } else {
 113         ret = (ret == Z_OK ? -ENOMEM : -EIO);
 114     }
 115
 116     deflateEnd(&strm);
 117
 118     return ret;
 119 }
 120
 121 /*
 122  * qcow2_decompress()
 123  *
 124  * Decompress some data (not more than @src_size bytes) to produce exactly
 125  * @dest_size bytes.
 126  *
 127  * @dest - destination buffer, @dest_size bytes
 128  * @src - source buffer, @src_size bytes
 129  *
 130  * Returns: 0 on success
 131  *          -1 on fail
 132  */
 133 static ssize_t qcow2_decompress(void *dest, size_t dest_size,
 134                                 const void *src, size_t src_size)
 135 {
 136     int ret = 0;
 137     z_stream strm;
 138
 139     memset(&strm, 0, sizeof(strm));
 140     strm.avail_in = src_size;
 141     strm.next_in = (void *) src;
 142     strm.avail_out = dest_size;
 143     strm.next_out = dest;
 144
 145     ret = inflateInit2(&strm, -12);
 146     if (ret != Z_OK) {
 147         return -1;
 148     }
 149
 150     ret = inflate(&strm, Z_FINISH);
 151     if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) || strm.avail_out != 0) {
 152         /*
 153          * We approve Z_BUF_ERROR because we need @dest buffer to be filled, but
 154          * @src buffer may be processed partly (because in qcow2 we know size of
 155          * compressed data with precision of one sector)
 156          */
 157         ret = -1;
 158     }
 159
 160     inflateEnd(&strm);
 161
 162     return ret;
 163 }
 164
 165 static int qcow2_compress_pool_func(void *opaque)
 166 {
 167     Qcow2CompressData *data = opaque;
 168
 169     data->ret = data->func(data->dest, data->dest_size,
 170                            data->src, data->src_size);
 171
 172     return 0;
 173 }
 174
 175 static ssize_t coroutine_fn
 176 qcow2_co_do_compress(BlockDriverState *bs, void *dest, size_t dest_size,
 177                      const void *src, size_t src_size, Qcow2CompressFunc func)
 178 {
 179     Qcow2CompressData arg = {
 180         .dest = dest,
 181         .dest_size = dest_size,
 182         .src = src,
 183         .src_size = src_size,
 184         .func = func,
 185     };
 186
 187     qcow2_co_process(bs, qcow2_compress_pool_func, &arg);
 188
 189     return arg.ret;
 190 }
 191
 192 ssize_t coroutine_fn
 193 qcow2_co_compress(BlockDriverState *bs, void *dest, size_t dest_size,
 194                   const void *src, size_t src_size)
 195 {
 196     return qcow2_co_do_compress(bs, dest, dest_size, src, src_size,
 197                                 qcow2_compress);
 198 }
 199
 200 ssize_t coroutine_fn
 201 qcow2_co_decompress(BlockDriverState *bs, void *dest, size_t dest_size,
 202                     const void *src, size_t src_size)
 203 {
 204     return qcow2_co_do_compress(bs, dest, dest_size, src, src_size,
 205                                 qcow2_decompress);
 206 }
 207
 208
 209 /*
 210  * Cryptography
 211  */
 212
 213 /*
 214  * Qcow2EncDecFunc: common prototype of qcrypto_block_encrypt() and
 215  * qcrypto_block_decrypt() functions.
 216  */
 217 typedef int (*Qcow2EncDecFunc)(QCryptoBlock *block, uint64_t offset,
 218                                uint8_t *buf, size_t len, Error **errp);
 219
 220 typedef struct Qcow2EncDecData {
 221     QCryptoBlock *block;
 222     uint64_t offset;
 223     uint8_t *buf;
 224     size_t len;
 225
 226     Qcow2EncDecFunc func;
 227 } Qcow2EncDecData;
 228
 229 static int qcow2_encdec_pool_func(void *opaque)
 230 {
 231     Qcow2EncDecData *data = opaque;
 232
 233     return data->func(data->block, data->offset, data->buf, data->len, NULL);
 234 }
 235
 236 static int coroutine_fn
 237 qcow2_co_encdec(BlockDriverState *bs, uint64_t host_offset,
 238                 uint64_t guest_offset, void *buf, size_t len,
 239                 Qcow2EncDecFunc func)
 240 {
 241     BDRVQcow2State *s = bs->opaque;
 242     Qcow2EncDecData arg = {
 243         .block = s->crypto,
 244         .offset = s->crypt_physical_offset ? host_offset : guest_offset,
 245         .buf = buf,
 246         .len = len,
 247         .func = func,
 248     };
 249
 250     assert(QEMU_IS_ALIGNED(guest_offset, BDRV_SECTOR_SIZE));
 251     assert(QEMU_IS_ALIGNED(host_offset, BDRV_SECTOR_SIZE));
 252     assert(QEMU_IS_ALIGNED(len, BDRV_SECTOR_SIZE));
 253     assert(s->crypto);
 254
 255     return len == 0 ? 0 : qcow2_co_process(bs, qcow2_encdec_pool_func, &arg);
 256 }
 257
 258 /*
 259  * qcow2_co_encrypt()
 260  *
 261  * Encrypts one or more contiguous aligned sectors
 262  *
 263  * @host_offset - underlying storage offset of the first sector of the
 264  * data to be encrypted
 265  *
 266  * @guest_offset - guest (virtual) offset of the first sector of the
 267  * data to be encrypted
 268  *
 269  * @buf - buffer with the data to encrypt, that after encryption
 270  *        will be written to the underlying storage device at
 271  *        @host_offset
 272  *
 273  * @len - length of the buffer (must be a BDRV_SECTOR_SIZE multiple)
 274  *
 275  * Depending on the encryption method, @host_offset and/or @guest_offset
 276  * may be used for generating the initialization vector for
 277  * encryption.
 278  *
 279  * Note that while the whole range must be aligned on sectors, it
 280  * does not have to be aligned on clusters and can also cross cluster
 281  * boundaries
 282  */
 283 int coroutine_fn
 284 qcow2_co_encrypt(BlockDriverState *bs, uint64_t host_offset,
 285                  uint64_t guest_offset, void *buf, size_t len)
 286 {
 287     return qcow2_co_encdec(bs, host_offset, guest_offset, buf, len,
 288                            qcrypto_block_encrypt);
 289 }
 290
 291 /*
 292  * qcow2_co_decrypt()
 293  *
 294  * Decrypts one or more contiguous aligned sectors
 295  * Similar to qcow2_co_encrypt
 296  */
 297 int coroutine_fn
 298 qcow2_co_decrypt(BlockDriverState *bs, uint64_t host_offset,
 299                  uint64_t guest_offset, void *buf, size_t len)
 300 {
 301     return qcow2_co_encdec(bs, host_offset, guest_offset, buf, len,
 302                            qcrypto_block_decrypt);
 303 }