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, &cur_entry, 111 sizeof(cur_entry)); 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 bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds, 159 BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY, false, 160 errp); 161 if (!bs->file) { 162 ret = -EINVAL; 163 goto fail; 164 } 165 166 /* Open the log file */ 167 s->log_file = bdrv_open_child(NULL, options, "log", bs, &child_of_bds, 168 BDRV_CHILD_METADATA, false, errp); 169 if (!s->log_file) { 170 ret = -EINVAL; 171 goto fail; 172 } 173 174 log_append = qemu_opt_get_bool(opts, "log-append", false); 175 176 if (log_append) { 177 struct log_write_super log_sb = { 0, 0, 0, 0 }; 178 179 if (qemu_opt_find(opts, "log-sector-size")) { 180 ret = -EINVAL; 181 error_setg(errp, "log-append and log-sector-size are mutually " 182 "exclusive"); 183 goto fail_log; 184 } 185 186 /* Read log superblock or fake one for an empty log */ 187 if (!bdrv_getlength(s->log_file->bs)) { 188 log_sb.magic = cpu_to_le64(WRITE_LOG_MAGIC); 189 log_sb.version = cpu_to_le64(WRITE_LOG_VERSION); 190 log_sb.nr_entries = cpu_to_le64(0); 191 log_sb.sectorsize = cpu_to_le32(BDRV_SECTOR_SIZE); 192 } else { 193 ret = bdrv_pread(s->log_file, 0, &log_sb, sizeof(log_sb)); 194 if (ret < 0) { 195 error_setg_errno(errp, -ret, "Could not read log superblock"); 196 goto fail_log; 197 } 198 } 199 200 if (log_sb.magic != cpu_to_le64(WRITE_LOG_MAGIC)) { 201 ret = -EINVAL; 202 error_setg(errp, "Invalid log superblock magic"); 203 goto fail_log; 204 } 205 206 if (log_sb.version != cpu_to_le64(WRITE_LOG_VERSION)) { 207 ret = -EINVAL; 208 error_setg(errp, "Unsupported log version %"PRIu64, 209 le64_to_cpu(log_sb.version)); 210 goto fail_log; 211 } 212 213 log_sector_size = le32_to_cpu(log_sb.sectorsize); 214 s->cur_log_sector = 1; 215 s->nr_entries = 0; 216 217 if (blk_log_writes_sector_size_valid(log_sector_size)) { 218 s->cur_log_sector = 219 blk_log_writes_find_cur_log_sector(s->log_file, log_sector_size, 220 le64_to_cpu(log_sb.nr_entries), &local_err); 221 if (local_err) { 222 ret = -EINVAL; 223 error_propagate(errp, local_err); 224 goto fail_log; 225 } 226 227 s->nr_entries = le64_to_cpu(log_sb.nr_entries); 228 } 229 } else { 230 log_sector_size = qemu_opt_get_size(opts, "log-sector-size", 231 BDRV_SECTOR_SIZE); 232 s->cur_log_sector = 1; 233 s->nr_entries = 0; 234 } 235 236 if (!blk_log_writes_sector_size_valid(log_sector_size)) { 237 ret = -EINVAL; 238 error_setg(errp, "Invalid log sector size %"PRIu64, log_sector_size); 239 goto fail_log; 240 } 241 242 s->sectorsize = log_sector_size; 243 s->sectorbits = blk_log_writes_log2(log_sector_size); 244 s->update_interval = qemu_opt_get_number(opts, "log-super-update-interval", 245 4096); 246 if (!s->update_interval) { 247 ret = -EINVAL; 248 error_setg(errp, "Invalid log superblock update interval %"PRIu64, 249 s->update_interval); 250 goto fail_log; 251 } 252 253 ret = 0; 254 fail_log: 255 if (ret < 0) { 256 bdrv_unref_child(bs, s->log_file); 257 s->log_file = NULL; 258 } 259 fail: 260 if (ret < 0) { 261 bdrv_unref_child(bs, bs->file); 262 bs->file = NULL; 263 } 264 qemu_opts_del(opts); 265 return ret; 266 } 267 268 static void blk_log_writes_close(BlockDriverState *bs) 269 { 270 BDRVBlkLogWritesState *s = bs->opaque; 271 272 bdrv_unref_child(bs, s->log_file); 273 s->log_file = NULL; 274 } 275 276 static int64_t blk_log_writes_getlength(BlockDriverState *bs) 277 { 278 return bdrv_getlength(bs->file->bs); 279 } 280 281 static void blk_log_writes_child_perm(BlockDriverState *bs, BdrvChild *c, 282 BdrvChildRole role, 283 BlockReopenQueue *ro_q, 284 uint64_t perm, uint64_t shrd, 285 uint64_t *nperm, uint64_t *nshrd) 286 { 287 if (!c) { 288 *nperm = perm & DEFAULT_PERM_PASSTHROUGH; 289 *nshrd = (shrd & DEFAULT_PERM_PASSTHROUGH) | DEFAULT_PERM_UNCHANGED; 290 return; 291 } 292 293 bdrv_default_perms(bs, c, role, ro_q, perm, shrd, 294 nperm, nshrd); 295 } 296 297 static void blk_log_writes_refresh_limits(BlockDriverState *bs, Error **errp) 298 { 299 BDRVBlkLogWritesState *s = bs->opaque; 300 bs->bl.request_alignment = s->sectorsize; 301 } 302 303 static int coroutine_fn 304 blk_log_writes_co_preadv(BlockDriverState *bs, uint64_t offset, uint64_t bytes, 305 QEMUIOVector *qiov, int flags) 306 { 307 return bdrv_co_preadv(bs->file, offset, bytes, qiov, flags); 308 } 309 310 typedef struct BlkLogWritesFileReq { 311 BlockDriverState *bs; 312 uint64_t offset; 313 uint64_t bytes; 314 int file_flags; 315 QEMUIOVector *qiov; 316 int (*func)(struct BlkLogWritesFileReq *r); 317 int file_ret; 318 } BlkLogWritesFileReq; 319 320 typedef struct { 321 BlockDriverState *bs; 322 QEMUIOVector *qiov; 323 struct log_write_entry entry; 324 uint64_t zero_size; 325 int log_ret; 326 } BlkLogWritesLogReq; 327 328 static void coroutine_fn blk_log_writes_co_do_log(BlkLogWritesLogReq *lr) 329 { 330 BDRVBlkLogWritesState *s = lr->bs->opaque; 331 uint64_t cur_log_offset = s->cur_log_sector << s->sectorbits; 332 333 s->nr_entries++; 334 s->cur_log_sector += 335 ROUND_UP(lr->qiov->size, s->sectorsize) >> s->sectorbits; 336 337 lr->log_ret = bdrv_co_pwritev(s->log_file, cur_log_offset, lr->qiov->size, 338 lr->qiov, 0); 339 340 /* Logging for the "write zeroes" operation */ 341 if (lr->log_ret == 0 && lr->zero_size) { 342 cur_log_offset = s->cur_log_sector << s->sectorbits; 343 s->cur_log_sector += 344 ROUND_UP(lr->zero_size, s->sectorsize) >> s->sectorbits; 345 346 lr->log_ret = bdrv_co_pwrite_zeroes(s->log_file, cur_log_offset, 347 lr->zero_size, 0); 348 } 349 350 /* Update super block on flush or every update interval */ 351 if (lr->log_ret == 0 && ((lr->entry.flags & LOG_FLUSH_FLAG) 352 || (s->nr_entries % s->update_interval == 0))) 353 { 354 struct log_write_super super = { 355 .magic = cpu_to_le64(WRITE_LOG_MAGIC), 356 .version = cpu_to_le64(WRITE_LOG_VERSION), 357 .nr_entries = cpu_to_le64(s->nr_entries), 358 .sectorsize = cpu_to_le32(s->sectorsize), 359 }; 360 void *zeroes = g_malloc0(s->sectorsize - sizeof(super)); 361 QEMUIOVector qiov; 362 363 qemu_iovec_init(&qiov, 2); 364 qemu_iovec_add(&qiov, &super, sizeof(super)); 365 qemu_iovec_add(&qiov, zeroes, s->sectorsize - sizeof(super)); 366 367 lr->log_ret = 368 bdrv_co_pwritev(s->log_file, 0, s->sectorsize, &qiov, 0); 369 if (lr->log_ret == 0) { 370 lr->log_ret = bdrv_co_flush(s->log_file->bs); 371 } 372 qemu_iovec_destroy(&qiov); 373 g_free(zeroes); 374 } 375 } 376 377 static void coroutine_fn blk_log_writes_co_do_file(BlkLogWritesFileReq *fr) 378 { 379 fr->file_ret = fr->func(fr); 380 } 381 382 static int coroutine_fn 383 blk_log_writes_co_log(BlockDriverState *bs, uint64_t offset, uint64_t bytes, 384 QEMUIOVector *qiov, int flags, 385 int (*file_func)(BlkLogWritesFileReq *r), 386 uint64_t entry_flags, bool is_zero_write) 387 { 388 QEMUIOVector log_qiov; 389 size_t niov = qiov ? qiov->niov : 0; 390 BDRVBlkLogWritesState *s = bs->opaque; 391 BlkLogWritesFileReq fr = { 392 .bs = bs, 393 .offset = offset, 394 .bytes = bytes, 395 .file_flags = flags, 396 .qiov = qiov, 397 .func = file_func, 398 }; 399 BlkLogWritesLogReq lr = { 400 .bs = bs, 401 .qiov = &log_qiov, 402 .entry = { 403 .sector = cpu_to_le64(offset >> s->sectorbits), 404 .nr_sectors = cpu_to_le64(bytes >> s->sectorbits), 405 .flags = cpu_to_le64(entry_flags), 406 .data_len = 0, 407 }, 408 .zero_size = is_zero_write ? bytes : 0, 409 }; 410 void *zeroes = g_malloc0(s->sectorsize - sizeof(lr.entry)); 411 412 assert((1 << s->sectorbits) == s->sectorsize); 413 assert(bs->bl.request_alignment == s->sectorsize); 414 assert(QEMU_IS_ALIGNED(offset, bs->bl.request_alignment)); 415 assert(QEMU_IS_ALIGNED(bytes, bs->bl.request_alignment)); 416 417 qemu_iovec_init(&log_qiov, niov + 2); 418 qemu_iovec_add(&log_qiov, &lr.entry, sizeof(lr.entry)); 419 qemu_iovec_add(&log_qiov, zeroes, s->sectorsize - sizeof(lr.entry)); 420 if (qiov) { 421 qemu_iovec_concat(&log_qiov, qiov, 0, qiov->size); 422 } 423 424 blk_log_writes_co_do_file(&fr); 425 blk_log_writes_co_do_log(&lr); 426 427 qemu_iovec_destroy(&log_qiov); 428 g_free(zeroes); 429 430 if (lr.log_ret < 0) { 431 return lr.log_ret; 432 } 433 434 return fr.file_ret; 435 } 436 437 static int coroutine_fn 438 blk_log_writes_co_do_file_pwritev(BlkLogWritesFileReq *fr) 439 { 440 return bdrv_co_pwritev(fr->bs->file, fr->offset, fr->bytes, 441 fr->qiov, fr->file_flags); 442 } 443 444 static int coroutine_fn 445 blk_log_writes_co_do_file_pwrite_zeroes(BlkLogWritesFileReq *fr) 446 { 447 return bdrv_co_pwrite_zeroes(fr->bs->file, fr->offset, fr->bytes, 448 fr->file_flags); 449 } 450 451 static int coroutine_fn blk_log_writes_co_do_file_flush(BlkLogWritesFileReq *fr) 452 { 453 return bdrv_co_flush(fr->bs->file->bs); 454 } 455 456 static int coroutine_fn 457 blk_log_writes_co_do_file_pdiscard(BlkLogWritesFileReq *fr) 458 { 459 return bdrv_co_pdiscard(fr->bs->file, fr->offset, fr->bytes); 460 } 461 462 static int coroutine_fn 463 blk_log_writes_co_pwritev(BlockDriverState *bs, uint64_t offset, uint64_t bytes, 464 QEMUIOVector *qiov, int flags) 465 { 466 return blk_log_writes_co_log(bs, offset, bytes, qiov, flags, 467 blk_log_writes_co_do_file_pwritev, 0, false); 468 } 469 470 static int coroutine_fn 471 blk_log_writes_co_pwrite_zeroes(BlockDriverState *bs, int64_t offset, int bytes, 472 BdrvRequestFlags flags) 473 { 474 return blk_log_writes_co_log(bs, offset, bytes, NULL, flags, 475 blk_log_writes_co_do_file_pwrite_zeroes, 0, 476 true); 477 } 478 479 static int coroutine_fn blk_log_writes_co_flush_to_disk(BlockDriverState *bs) 480 { 481 return blk_log_writes_co_log(bs, 0, 0, NULL, 0, 482 blk_log_writes_co_do_file_flush, 483 LOG_FLUSH_FLAG, false); 484 } 485 486 static int coroutine_fn 487 blk_log_writes_co_pdiscard(BlockDriverState *bs, int64_t offset, int count) 488 { 489 return blk_log_writes_co_log(bs, offset, count, NULL, 0, 490 blk_log_writes_co_do_file_pdiscard, 491 LOG_DISCARD_FLAG, false); 492 } 493 494 static const char *const blk_log_writes_strong_runtime_opts[] = { 495 "log-append", 496 "log-sector-size", 497 498 NULL 499 }; 500 501 static BlockDriver bdrv_blk_log_writes = { 502 .format_name = "blklogwrites", 503 .instance_size = sizeof(BDRVBlkLogWritesState), 504 505 .bdrv_open = blk_log_writes_open, 506 .bdrv_close = blk_log_writes_close, 507 .bdrv_getlength = blk_log_writes_getlength, 508 .bdrv_child_perm = blk_log_writes_child_perm, 509 .bdrv_refresh_limits = blk_log_writes_refresh_limits, 510 511 .bdrv_co_preadv = blk_log_writes_co_preadv, 512 .bdrv_co_pwritev = blk_log_writes_co_pwritev, 513 .bdrv_co_pwrite_zeroes = blk_log_writes_co_pwrite_zeroes, 514 .bdrv_co_flush_to_disk = blk_log_writes_co_flush_to_disk, 515 .bdrv_co_pdiscard = blk_log_writes_co_pdiscard, 516 517 .is_filter = true, 518 .strong_runtime_opts = blk_log_writes_strong_runtime_opts, 519 }; 520 521 static void bdrv_blk_log_writes_init(void) 522 { 523 bdrv_register(&bdrv_blk_log_writes); 524 } 525 526 block_init(bdrv_blk_log_writes_init); 527