1 /* 2 * Write logging blk driver based on blkverify and blkdebug. 3 * 4 * Copyright (c) 2017 Tuomas Tynkkynen <tuomas@tuxera.com> 5 * Copyright (c) 2018 Aapo Vienamo <aapo@tuxera.com> 6 * Copyright (c) 2018 Ari Sundholm <ari@tuxera.com> 7 * 8 * This work is licensed under the terms of the GNU GPL, version 2 or later. 9 * See the COPYING file in the top-level directory. 10 */ 11 12 #include "qemu/osdep.h" 13 #include "qapi/error.h" 14 #include "qemu/sockets.h" /* for EINPROGRESS on Windows */ 15 #include "block/block_int.h" 16 #include "qapi/qmp/qdict.h" 17 #include "qapi/qmp/qstring.h" 18 #include "qemu/cutils.h" 19 #include "qemu/module.h" 20 #include "qemu/option.h" 21 22 /* Disk format stuff - taken from Linux drivers/md/dm-log-writes.c */ 23 24 #define LOG_FLUSH_FLAG (1 << 0) 25 #define LOG_FUA_FLAG (1 << 1) 26 #define LOG_DISCARD_FLAG (1 << 2) 27 #define LOG_MARK_FLAG (1 << 3) 28 #define LOG_FLAG_MASK (LOG_FLUSH_FLAG \ 29 | LOG_FUA_FLAG \ 30 | LOG_DISCARD_FLAG \ 31 | LOG_MARK_FLAG) 32 33 #define WRITE_LOG_VERSION 1ULL 34 #define WRITE_LOG_MAGIC 0x6a736677736872ULL 35 36 /* All fields are little-endian. */ 37 struct log_write_super { 38 uint64_t magic; 39 uint64_t version; 40 uint64_t nr_entries; 41 uint32_t sectorsize; 42 } QEMU_PACKED; 43 44 struct log_write_entry { 45 uint64_t sector; 46 uint64_t nr_sectors; 47 uint64_t flags; 48 uint64_t data_len; 49 } QEMU_PACKED; 50 51 /* End of disk format structures. */ 52 53 typedef struct { 54 BdrvChild *log_file; 55 uint32_t sectorsize; 56 uint32_t sectorbits; 57 uint64_t cur_log_sector; 58 uint64_t nr_entries; 59 uint64_t update_interval; 60 } BDRVBlkLogWritesState; 61 62 static QemuOptsList runtime_opts = { 63 .name = "blklogwrites", 64 .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head), 65 .desc = { 66 { 67 .name = "log-append", 68 .type = QEMU_OPT_BOOL, 69 .help = "Append to an existing log", 70 }, 71 { 72 .name = "log-sector-size", 73 .type = QEMU_OPT_SIZE, 74 .help = "Log sector size", 75 }, 76 { 77 .name = "log-super-update-interval", 78 .type = QEMU_OPT_NUMBER, 79 .help = "Log superblock update interval (# of write requests)", 80 }, 81 { /* end of list */ } 82 }, 83 }; 84 85 static inline uint32_t blk_log_writes_log2(uint32_t value) 86 { 87 assert(value > 0); 88 return 31 - clz32(value); 89 } 90 91 static inline bool blk_log_writes_sector_size_valid(uint32_t sector_size) 92 { 93 return is_power_of_2(sector_size) && 94 sector_size >= sizeof(struct log_write_super) && 95 sector_size >= sizeof(struct log_write_entry) && 96 sector_size < (1ull << 24); 97 } 98 99 static uint64_t blk_log_writes_find_cur_log_sector(BdrvChild *log, 100 uint32_t sector_size, 101 uint64_t nr_entries, 102 Error **errp) 103 { 104 uint64_t cur_sector = 1; 105 uint64_t cur_idx = 0; 106 uint32_t sector_bits = blk_log_writes_log2(sector_size); 107 struct log_write_entry cur_entry; 108 109 while (cur_idx < nr_entries) { 110 int read_ret = bdrv_pread(log, cur_sector << sector_bits, 111 sizeof(cur_entry), &cur_entry, 0); 112 if (read_ret < 0) { 113 error_setg_errno(errp, -read_ret, 114 "Failed to read log entry %"PRIu64, cur_idx); 115 return (uint64_t)-1ull; 116 } 117 118 if (cur_entry.flags & ~cpu_to_le64(LOG_FLAG_MASK)) { 119 error_setg(errp, "Invalid flags 0x%"PRIx64" in log entry %"PRIu64, 120 le64_to_cpu(cur_entry.flags), cur_idx); 121 return (uint64_t)-1ull; 122 } 123 124 /* Account for the sector of the entry itself */ 125 ++cur_sector; 126 127 /* 128 * Account for the data of the write. 129 * For discards, this data is not present. 130 */ 131 if (!(cur_entry.flags & cpu_to_le64(LOG_DISCARD_FLAG))) { 132 cur_sector += le64_to_cpu(cur_entry.nr_sectors); 133 } 134 135 ++cur_idx; 136 } 137 138 return cur_sector; 139 } 140 141 static int blk_log_writes_open(BlockDriverState *bs, QDict *options, int flags, 142 Error **errp) 143 { 144 BDRVBlkLogWritesState *s = bs->opaque; 145 QemuOpts *opts; 146 Error *local_err = NULL; 147 int ret; 148 uint64_t log_sector_size; 149 bool log_append; 150 151 opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort); 152 if (!qemu_opts_absorb_qdict(opts, options, errp)) { 153 ret = -EINVAL; 154 goto fail; 155 } 156 157 /* Open the file */ 158 ret = bdrv_open_file_child(NULL, options, "file", bs, errp); 159 if (ret < 0) { 160 goto fail; 161 } 162 163 /* Open the log file */ 164 s->log_file = bdrv_open_child(NULL, options, "log", bs, &child_of_bds, 165 BDRV_CHILD_METADATA, false, errp); 166 if (!s->log_file) { 167 ret = -EINVAL; 168 goto fail; 169 } 170 171 log_append = qemu_opt_get_bool(opts, "log-append", false); 172 173 if (log_append) { 174 struct log_write_super log_sb = { 0, 0, 0, 0 }; 175 176 if (qemu_opt_find(opts, "log-sector-size")) { 177 ret = -EINVAL; 178 error_setg(errp, "log-append and log-sector-size are mutually " 179 "exclusive"); 180 goto fail_log; 181 } 182 183 /* Read log superblock or fake one for an empty log */ 184 if (!bdrv_getlength(s->log_file->bs)) { 185 log_sb.magic = cpu_to_le64(WRITE_LOG_MAGIC); 186 log_sb.version = cpu_to_le64(WRITE_LOG_VERSION); 187 log_sb.nr_entries = cpu_to_le64(0); 188 log_sb.sectorsize = cpu_to_le32(BDRV_SECTOR_SIZE); 189 } else { 190 ret = bdrv_pread(s->log_file, 0, sizeof(log_sb), &log_sb, 0); 191 if (ret < 0) { 192 error_setg_errno(errp, -ret, "Could not read log superblock"); 193 goto fail_log; 194 } 195 } 196 197 if (log_sb.magic != cpu_to_le64(WRITE_LOG_MAGIC)) { 198 ret = -EINVAL; 199 error_setg(errp, "Invalid log superblock magic"); 200 goto fail_log; 201 } 202 203 if (log_sb.version != cpu_to_le64(WRITE_LOG_VERSION)) { 204 ret = -EINVAL; 205 error_setg(errp, "Unsupported log version %"PRIu64, 206 le64_to_cpu(log_sb.version)); 207 goto fail_log; 208 } 209 210 log_sector_size = le32_to_cpu(log_sb.sectorsize); 211 s->cur_log_sector = 1; 212 s->nr_entries = 0; 213 214 if (blk_log_writes_sector_size_valid(log_sector_size)) { 215 s->cur_log_sector = 216 blk_log_writes_find_cur_log_sector(s->log_file, log_sector_size, 217 le64_to_cpu(log_sb.nr_entries), &local_err); 218 if (local_err) { 219 ret = -EINVAL; 220 error_propagate(errp, local_err); 221 goto fail_log; 222 } 223 224 s->nr_entries = le64_to_cpu(log_sb.nr_entries); 225 } 226 } else { 227 log_sector_size = qemu_opt_get_size(opts, "log-sector-size", 228 BDRV_SECTOR_SIZE); 229 s->cur_log_sector = 1; 230 s->nr_entries = 0; 231 } 232 233 if (!blk_log_writes_sector_size_valid(log_sector_size)) { 234 ret = -EINVAL; 235 error_setg(errp, "Invalid log sector size %"PRIu64, log_sector_size); 236 goto fail_log; 237 } 238 239 s->sectorsize = log_sector_size; 240 s->sectorbits = blk_log_writes_log2(log_sector_size); 241 s->update_interval = qemu_opt_get_number(opts, "log-super-update-interval", 242 4096); 243 if (!s->update_interval) { 244 ret = -EINVAL; 245 error_setg(errp, "Invalid log superblock update interval %"PRIu64, 246 s->update_interval); 247 goto fail_log; 248 } 249 250 ret = 0; 251 fail_log: 252 if (ret < 0) { 253 bdrv_unref_child(bs, s->log_file); 254 s->log_file = NULL; 255 } 256 fail: 257 qemu_opts_del(opts); 258 return ret; 259 } 260 261 static void blk_log_writes_close(BlockDriverState *bs) 262 { 263 BDRVBlkLogWritesState *s = bs->opaque; 264 265 bdrv_unref_child(bs, s->log_file); 266 s->log_file = NULL; 267 } 268 269 static int64_t blk_log_writes_getlength(BlockDriverState *bs) 270 { 271 return bdrv_getlength(bs->file->bs); 272 } 273 274 static void blk_log_writes_child_perm(BlockDriverState *bs, BdrvChild *c, 275 BdrvChildRole role, 276 BlockReopenQueue *ro_q, 277 uint64_t perm, uint64_t shrd, 278 uint64_t *nperm, uint64_t *nshrd) 279 { 280 if (!c) { 281 *nperm = perm & DEFAULT_PERM_PASSTHROUGH; 282 *nshrd = (shrd & DEFAULT_PERM_PASSTHROUGH) | DEFAULT_PERM_UNCHANGED; 283 return; 284 } 285 286 bdrv_default_perms(bs, c, role, ro_q, perm, shrd, 287 nperm, nshrd); 288 } 289 290 static void blk_log_writes_refresh_limits(BlockDriverState *bs, Error **errp) 291 { 292 BDRVBlkLogWritesState *s = bs->opaque; 293 bs->bl.request_alignment = s->sectorsize; 294 } 295 296 static int coroutine_fn 297 blk_log_writes_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes, 298 QEMUIOVector *qiov, BdrvRequestFlags flags) 299 { 300 return bdrv_co_preadv(bs->file, offset, bytes, qiov, flags); 301 } 302 303 typedef struct BlkLogWritesFileReq { 304 BlockDriverState *bs; 305 uint64_t offset; 306 uint64_t bytes; 307 int file_flags; 308 QEMUIOVector *qiov; 309 int (*func)(struct BlkLogWritesFileReq *r); 310 int file_ret; 311 } BlkLogWritesFileReq; 312 313 typedef struct { 314 BlockDriverState *bs; 315 QEMUIOVector *qiov; 316 struct log_write_entry entry; 317 uint64_t zero_size; 318 int log_ret; 319 } BlkLogWritesLogReq; 320 321 static void coroutine_fn blk_log_writes_co_do_log(BlkLogWritesLogReq *lr) 322 { 323 BDRVBlkLogWritesState *s = lr->bs->opaque; 324 uint64_t cur_log_offset = s->cur_log_sector << s->sectorbits; 325 326 s->nr_entries++; 327 s->cur_log_sector += 328 ROUND_UP(lr->qiov->size, s->sectorsize) >> s->sectorbits; 329 330 lr->log_ret = bdrv_co_pwritev(s->log_file, cur_log_offset, lr->qiov->size, 331 lr->qiov, 0); 332 333 /* Logging for the "write zeroes" operation */ 334 if (lr->log_ret == 0 && lr->zero_size) { 335 cur_log_offset = s->cur_log_sector << s->sectorbits; 336 s->cur_log_sector += 337 ROUND_UP(lr->zero_size, s->sectorsize) >> s->sectorbits; 338 339 lr->log_ret = bdrv_co_pwrite_zeroes(s->log_file, cur_log_offset, 340 lr->zero_size, 0); 341 } 342 343 /* Update super block on flush or every update interval */ 344 if (lr->log_ret == 0 && ((lr->entry.flags & LOG_FLUSH_FLAG) 345 || (s->nr_entries % s->update_interval == 0))) 346 { 347 struct log_write_super super = { 348 .magic = cpu_to_le64(WRITE_LOG_MAGIC), 349 .version = cpu_to_le64(WRITE_LOG_VERSION), 350 .nr_entries = cpu_to_le64(s->nr_entries), 351 .sectorsize = cpu_to_le32(s->sectorsize), 352 }; 353 void *zeroes = g_malloc0(s->sectorsize - sizeof(super)); 354 QEMUIOVector qiov; 355 356 qemu_iovec_init(&qiov, 2); 357 qemu_iovec_add(&qiov, &super, sizeof(super)); 358 qemu_iovec_add(&qiov, zeroes, s->sectorsize - sizeof(super)); 359 360 lr->log_ret = 361 bdrv_co_pwritev(s->log_file, 0, s->sectorsize, &qiov, 0); 362 if (lr->log_ret == 0) { 363 lr->log_ret = bdrv_co_flush(s->log_file->bs); 364 } 365 qemu_iovec_destroy(&qiov); 366 g_free(zeroes); 367 } 368 } 369 370 static void coroutine_fn blk_log_writes_co_do_file(BlkLogWritesFileReq *fr) 371 { 372 fr->file_ret = fr->func(fr); 373 } 374 375 static int coroutine_fn 376 blk_log_writes_co_log(BlockDriverState *bs, uint64_t offset, uint64_t bytes, 377 QEMUIOVector *qiov, int flags, 378 int (*file_func)(BlkLogWritesFileReq *r), 379 uint64_t entry_flags, bool is_zero_write) 380 { 381 QEMUIOVector log_qiov; 382 size_t niov = qiov ? qiov->niov : 0; 383 BDRVBlkLogWritesState *s = bs->opaque; 384 BlkLogWritesFileReq fr = { 385 .bs = bs, 386 .offset = offset, 387 .bytes = bytes, 388 .file_flags = flags, 389 .qiov = qiov, 390 .func = file_func, 391 }; 392 BlkLogWritesLogReq lr = { 393 .bs = bs, 394 .qiov = &log_qiov, 395 .entry = { 396 .sector = cpu_to_le64(offset >> s->sectorbits), 397 .nr_sectors = cpu_to_le64(bytes >> s->sectorbits), 398 .flags = cpu_to_le64(entry_flags), 399 .data_len = 0, 400 }, 401 .zero_size = is_zero_write ? bytes : 0, 402 }; 403 void *zeroes = g_malloc0(s->sectorsize - sizeof(lr.entry)); 404 405 assert((1 << s->sectorbits) == s->sectorsize); 406 assert(bs->bl.request_alignment == s->sectorsize); 407 assert(QEMU_IS_ALIGNED(offset, bs->bl.request_alignment)); 408 assert(QEMU_IS_ALIGNED(bytes, bs->bl.request_alignment)); 409 410 qemu_iovec_init(&log_qiov, niov + 2); 411 qemu_iovec_add(&log_qiov, &lr.entry, sizeof(lr.entry)); 412 qemu_iovec_add(&log_qiov, zeroes, s->sectorsize - sizeof(lr.entry)); 413 if (qiov) { 414 qemu_iovec_concat(&log_qiov, qiov, 0, qiov->size); 415 } 416 417 blk_log_writes_co_do_file(&fr); 418 blk_log_writes_co_do_log(&lr); 419 420 qemu_iovec_destroy(&log_qiov); 421 g_free(zeroes); 422 423 if (lr.log_ret < 0) { 424 return lr.log_ret; 425 } 426 427 return fr.file_ret; 428 } 429 430 static int coroutine_fn 431 blk_log_writes_co_do_file_pwritev(BlkLogWritesFileReq *fr) 432 { 433 return bdrv_co_pwritev(fr->bs->file, fr->offset, fr->bytes, 434 fr->qiov, fr->file_flags); 435 } 436 437 static int coroutine_fn 438 blk_log_writes_co_do_file_pwrite_zeroes(BlkLogWritesFileReq *fr) 439 { 440 return bdrv_co_pwrite_zeroes(fr->bs->file, fr->offset, fr->bytes, 441 fr->file_flags); 442 } 443 444 static int coroutine_fn blk_log_writes_co_do_file_flush(BlkLogWritesFileReq *fr) 445 { 446 return bdrv_co_flush(fr->bs->file->bs); 447 } 448 449 static int coroutine_fn 450 blk_log_writes_co_do_file_pdiscard(BlkLogWritesFileReq *fr) 451 { 452 return bdrv_co_pdiscard(fr->bs->file, fr->offset, fr->bytes); 453 } 454 455 static int coroutine_fn 456 blk_log_writes_co_pwritev(BlockDriverState *bs, int64_t offset, int64_t bytes, 457 QEMUIOVector *qiov, BdrvRequestFlags flags) 458 { 459 return blk_log_writes_co_log(bs, offset, bytes, qiov, flags, 460 blk_log_writes_co_do_file_pwritev, 0, false); 461 } 462 463 static int coroutine_fn 464 blk_log_writes_co_pwrite_zeroes(BlockDriverState *bs, int64_t offset, 465 int64_t bytes, BdrvRequestFlags flags) 466 { 467 return blk_log_writes_co_log(bs, offset, bytes, NULL, flags, 468 blk_log_writes_co_do_file_pwrite_zeroes, 0, 469 true); 470 } 471 472 static int coroutine_fn blk_log_writes_co_flush_to_disk(BlockDriverState *bs) 473 { 474 return blk_log_writes_co_log(bs, 0, 0, NULL, 0, 475 blk_log_writes_co_do_file_flush, 476 LOG_FLUSH_FLAG, false); 477 } 478 479 static int coroutine_fn 480 blk_log_writes_co_pdiscard(BlockDriverState *bs, int64_t offset, int64_t bytes) 481 { 482 return blk_log_writes_co_log(bs, offset, bytes, NULL, 0, 483 blk_log_writes_co_do_file_pdiscard, 484 LOG_DISCARD_FLAG, false); 485 } 486 487 static const char *const blk_log_writes_strong_runtime_opts[] = { 488 "log-append", 489 "log-sector-size", 490 491 NULL 492 }; 493 494 static BlockDriver bdrv_blk_log_writes = { 495 .format_name = "blklogwrites", 496 .instance_size = sizeof(BDRVBlkLogWritesState), 497 498 .bdrv_open = blk_log_writes_open, 499 .bdrv_close = blk_log_writes_close, 500 .bdrv_getlength = blk_log_writes_getlength, 501 .bdrv_child_perm = blk_log_writes_child_perm, 502 .bdrv_refresh_limits = blk_log_writes_refresh_limits, 503 504 .bdrv_co_preadv = blk_log_writes_co_preadv, 505 .bdrv_co_pwritev = blk_log_writes_co_pwritev, 506 .bdrv_co_pwrite_zeroes = blk_log_writes_co_pwrite_zeroes, 507 .bdrv_co_flush_to_disk = blk_log_writes_co_flush_to_disk, 508 .bdrv_co_pdiscard = blk_log_writes_co_pdiscard, 509 510 .is_filter = true, 511 .strong_runtime_opts = blk_log_writes_strong_runtime_opts, 512 }; 513 514 static void bdrv_blk_log_writes_init(void) 515 { 516 bdrv_register(&bdrv_blk_log_writes); 517 } 518 519 block_init(bdrv_blk_log_writes_init); 520