1 /* 2 * Copyright (C) 2001-2003 Sistina Software (UK) Limited. 3 * 4 * This file is released under the GPL. 5 */ 6 7 #include "dm.h" 8 #include <linux/device-mapper.h> 9 10 #include <linux/module.h> 11 #include <linux/init.h> 12 #include <linux/blkdev.h> 13 #include <linux/bio.h> 14 #include <linux/dax.h> 15 #include <linux/slab.h> 16 #include <linux/log2.h> 17 18 #define DM_MSG_PREFIX "striped" 19 #define DM_IO_ERROR_THRESHOLD 15 20 21 struct stripe { 22 struct dm_dev *dev; 23 sector_t physical_start; 24 25 atomic_t error_count; 26 }; 27 28 struct stripe_c { 29 uint32_t stripes; 30 int stripes_shift; 31 32 /* The size of this target / num. stripes */ 33 sector_t stripe_width; 34 35 uint32_t chunk_size; 36 int chunk_size_shift; 37 38 /* Needed for handling events */ 39 struct dm_target *ti; 40 41 /* Work struct used for triggering events*/ 42 struct work_struct trigger_event; 43 44 struct stripe stripe[0]; 45 }; 46 47 /* 48 * An event is triggered whenever a drive 49 * drops out of a stripe volume. 50 */ 51 static void trigger_event(struct work_struct *work) 52 { 53 struct stripe_c *sc = container_of(work, struct stripe_c, 54 trigger_event); 55 dm_table_event(sc->ti->table); 56 } 57 58 static inline struct stripe_c *alloc_context(unsigned int stripes) 59 { 60 size_t len; 61 62 if (dm_array_too_big(sizeof(struct stripe_c), sizeof(struct stripe), 63 stripes)) 64 return NULL; 65 66 len = sizeof(struct stripe_c) + (sizeof(struct stripe) * stripes); 67 68 return kmalloc(len, GFP_KERNEL); 69 } 70 71 /* 72 * Parse a single <dev> <sector> pair 73 */ 74 static int get_stripe(struct dm_target *ti, struct stripe_c *sc, 75 unsigned int stripe, char **argv) 76 { 77 unsigned long long start; 78 char dummy; 79 int ret; 80 81 if (sscanf(argv[1], "%llu%c", &start, &dummy) != 1) 82 return -EINVAL; 83 84 ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), 85 &sc->stripe[stripe].dev); 86 if (ret) 87 return ret; 88 89 sc->stripe[stripe].physical_start = start; 90 91 return 0; 92 } 93 94 /* 95 * Construct a striped mapping. 96 * <number of stripes> <chunk size> [<dev_path> <offset>]+ 97 */ 98 static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv) 99 { 100 struct stripe_c *sc; 101 sector_t width, tmp_len; 102 uint32_t stripes; 103 uint32_t chunk_size; 104 int r; 105 unsigned int i; 106 107 if (argc < 2) { 108 ti->error = "Not enough arguments"; 109 return -EINVAL; 110 } 111 112 if (kstrtouint(argv[0], 10, &stripes) || !stripes) { 113 ti->error = "Invalid stripe count"; 114 return -EINVAL; 115 } 116 117 if (kstrtouint(argv[1], 10, &chunk_size) || !chunk_size) { 118 ti->error = "Invalid chunk_size"; 119 return -EINVAL; 120 } 121 122 width = ti->len; 123 if (sector_div(width, stripes)) { 124 ti->error = "Target length not divisible by " 125 "number of stripes"; 126 return -EINVAL; 127 } 128 129 tmp_len = width; 130 if (sector_div(tmp_len, chunk_size)) { 131 ti->error = "Target length not divisible by " 132 "chunk size"; 133 return -EINVAL; 134 } 135 136 /* 137 * Do we have enough arguments for that many stripes ? 138 */ 139 if (argc != (2 + 2 * stripes)) { 140 ti->error = "Not enough destinations " 141 "specified"; 142 return -EINVAL; 143 } 144 145 sc = alloc_context(stripes); 146 if (!sc) { 147 ti->error = "Memory allocation for striped context " 148 "failed"; 149 return -ENOMEM; 150 } 151 152 INIT_WORK(&sc->trigger_event, trigger_event); 153 154 /* Set pointer to dm target; used in trigger_event */ 155 sc->ti = ti; 156 sc->stripes = stripes; 157 sc->stripe_width = width; 158 159 if (stripes & (stripes - 1)) 160 sc->stripes_shift = -1; 161 else 162 sc->stripes_shift = __ffs(stripes); 163 164 r = dm_set_target_max_io_len(ti, chunk_size); 165 if (r) { 166 kfree(sc); 167 return r; 168 } 169 170 ti->num_flush_bios = stripes; 171 ti->num_discard_bios = stripes; 172 ti->num_secure_erase_bios = stripes; 173 ti->num_write_same_bios = stripes; 174 ti->num_write_zeroes_bios = stripes; 175 176 sc->chunk_size = chunk_size; 177 if (chunk_size & (chunk_size - 1)) 178 sc->chunk_size_shift = -1; 179 else 180 sc->chunk_size_shift = __ffs(chunk_size); 181 182 /* 183 * Get the stripe destinations. 184 */ 185 for (i = 0; i < stripes; i++) { 186 argv += 2; 187 188 r = get_stripe(ti, sc, i, argv); 189 if (r < 0) { 190 ti->error = "Couldn't parse stripe destination"; 191 while (i--) 192 dm_put_device(ti, sc->stripe[i].dev); 193 kfree(sc); 194 return r; 195 } 196 atomic_set(&(sc->stripe[i].error_count), 0); 197 } 198 199 ti->private = sc; 200 201 return 0; 202 } 203 204 static void stripe_dtr(struct dm_target *ti) 205 { 206 unsigned int i; 207 struct stripe_c *sc = (struct stripe_c *) ti->private; 208 209 for (i = 0; i < sc->stripes; i++) 210 dm_put_device(ti, sc->stripe[i].dev); 211 212 flush_work(&sc->trigger_event); 213 kfree(sc); 214 } 215 216 static void stripe_map_sector(struct stripe_c *sc, sector_t sector, 217 uint32_t *stripe, sector_t *result) 218 { 219 sector_t chunk = dm_target_offset(sc->ti, sector); 220 sector_t chunk_offset; 221 222 if (sc->chunk_size_shift < 0) 223 chunk_offset = sector_div(chunk, sc->chunk_size); 224 else { 225 chunk_offset = chunk & (sc->chunk_size - 1); 226 chunk >>= sc->chunk_size_shift; 227 } 228 229 if (sc->stripes_shift < 0) 230 *stripe = sector_div(chunk, sc->stripes); 231 else { 232 *stripe = chunk & (sc->stripes - 1); 233 chunk >>= sc->stripes_shift; 234 } 235 236 if (sc->chunk_size_shift < 0) 237 chunk *= sc->chunk_size; 238 else 239 chunk <<= sc->chunk_size_shift; 240 241 *result = chunk + chunk_offset; 242 } 243 244 static void stripe_map_range_sector(struct stripe_c *sc, sector_t sector, 245 uint32_t target_stripe, sector_t *result) 246 { 247 uint32_t stripe; 248 249 stripe_map_sector(sc, sector, &stripe, result); 250 if (stripe == target_stripe) 251 return; 252 253 /* round down */ 254 sector = *result; 255 if (sc->chunk_size_shift < 0) 256 *result -= sector_div(sector, sc->chunk_size); 257 else 258 *result = sector & ~(sector_t)(sc->chunk_size - 1); 259 260 if (target_stripe < stripe) 261 *result += sc->chunk_size; /* next chunk */ 262 } 263 264 static int stripe_map_range(struct stripe_c *sc, struct bio *bio, 265 uint32_t target_stripe) 266 { 267 sector_t begin, end; 268 269 stripe_map_range_sector(sc, bio->bi_iter.bi_sector, 270 target_stripe, &begin); 271 stripe_map_range_sector(sc, bio_end_sector(bio), 272 target_stripe, &end); 273 if (begin < end) { 274 bio_set_dev(bio, sc->stripe[target_stripe].dev->bdev); 275 bio->bi_iter.bi_sector = begin + 276 sc->stripe[target_stripe].physical_start; 277 bio->bi_iter.bi_size = to_bytes(end - begin); 278 return DM_MAPIO_REMAPPED; 279 } else { 280 /* The range doesn't map to the target stripe */ 281 bio_endio(bio); 282 return DM_MAPIO_SUBMITTED; 283 } 284 } 285 286 static int stripe_map(struct dm_target *ti, struct bio *bio) 287 { 288 struct stripe_c *sc = ti->private; 289 uint32_t stripe; 290 unsigned target_bio_nr; 291 292 if (bio->bi_opf & REQ_PREFLUSH) { 293 target_bio_nr = dm_bio_get_target_bio_nr(bio); 294 BUG_ON(target_bio_nr >= sc->stripes); 295 bio_set_dev(bio, sc->stripe[target_bio_nr].dev->bdev); 296 return DM_MAPIO_REMAPPED; 297 } 298 if (unlikely(bio_op(bio) == REQ_OP_DISCARD) || 299 unlikely(bio_op(bio) == REQ_OP_SECURE_ERASE) || 300 unlikely(bio_op(bio) == REQ_OP_WRITE_ZEROES) || 301 unlikely(bio_op(bio) == REQ_OP_WRITE_SAME)) { 302 target_bio_nr = dm_bio_get_target_bio_nr(bio); 303 BUG_ON(target_bio_nr >= sc->stripes); 304 return stripe_map_range(sc, bio, target_bio_nr); 305 } 306 307 stripe_map_sector(sc, bio->bi_iter.bi_sector, 308 &stripe, &bio->bi_iter.bi_sector); 309 310 bio->bi_iter.bi_sector += sc->stripe[stripe].physical_start; 311 bio_set_dev(bio, sc->stripe[stripe].dev->bdev); 312 313 return DM_MAPIO_REMAPPED; 314 } 315 316 #if IS_ENABLED(CONFIG_DAX_DRIVER) 317 static long stripe_dax_direct_access(struct dm_target *ti, pgoff_t pgoff, 318 long nr_pages, void **kaddr, pfn_t *pfn) 319 { 320 sector_t dev_sector, sector = pgoff * PAGE_SECTORS; 321 struct stripe_c *sc = ti->private; 322 struct dax_device *dax_dev; 323 struct block_device *bdev; 324 uint32_t stripe; 325 long ret; 326 327 stripe_map_sector(sc, sector, &stripe, &dev_sector); 328 dev_sector += sc->stripe[stripe].physical_start; 329 dax_dev = sc->stripe[stripe].dev->dax_dev; 330 bdev = sc->stripe[stripe].dev->bdev; 331 332 ret = bdev_dax_pgoff(bdev, dev_sector, nr_pages * PAGE_SIZE, &pgoff); 333 if (ret) 334 return ret; 335 return dax_direct_access(dax_dev, pgoff, nr_pages, kaddr, pfn); 336 } 337 338 static size_t stripe_dax_copy_from_iter(struct dm_target *ti, pgoff_t pgoff, 339 void *addr, size_t bytes, struct iov_iter *i) 340 { 341 sector_t dev_sector, sector = pgoff * PAGE_SECTORS; 342 struct stripe_c *sc = ti->private; 343 struct dax_device *dax_dev; 344 struct block_device *bdev; 345 uint32_t stripe; 346 347 stripe_map_sector(sc, sector, &stripe, &dev_sector); 348 dev_sector += sc->stripe[stripe].physical_start; 349 dax_dev = sc->stripe[stripe].dev->dax_dev; 350 bdev = sc->stripe[stripe].dev->bdev; 351 352 if (bdev_dax_pgoff(bdev, dev_sector, ALIGN(bytes, PAGE_SIZE), &pgoff)) 353 return 0; 354 return dax_copy_from_iter(dax_dev, pgoff, addr, bytes, i); 355 } 356 357 #else 358 #define stripe_dax_direct_access NULL 359 #define stripe_dax_copy_from_iter NULL 360 #endif 361 362 /* 363 * Stripe status: 364 * 365 * INFO 366 * #stripes [stripe_name <stripe_name>] [group word count] 367 * [error count 'A|D' <error count 'A|D'>] 368 * 369 * TABLE 370 * #stripes [stripe chunk size] 371 * [stripe_name physical_start <stripe_name physical_start>] 372 * 373 */ 374 375 static void stripe_status(struct dm_target *ti, status_type_t type, 376 unsigned status_flags, char *result, unsigned maxlen) 377 { 378 struct stripe_c *sc = (struct stripe_c *) ti->private; 379 unsigned int sz = 0; 380 unsigned int i; 381 382 switch (type) { 383 case STATUSTYPE_INFO: 384 DMEMIT("%d ", sc->stripes); 385 for (i = 0; i < sc->stripes; i++) { 386 DMEMIT("%s ", sc->stripe[i].dev->name); 387 } 388 DMEMIT("1 "); 389 for (i = 0; i < sc->stripes; i++) { 390 DMEMIT("%c", atomic_read(&(sc->stripe[i].error_count)) ? 391 'D' : 'A'); 392 } 393 break; 394 395 case STATUSTYPE_TABLE: 396 DMEMIT("%d %llu", sc->stripes, 397 (unsigned long long)sc->chunk_size); 398 for (i = 0; i < sc->stripes; i++) 399 DMEMIT(" %s %llu", sc->stripe[i].dev->name, 400 (unsigned long long)sc->stripe[i].physical_start); 401 break; 402 } 403 } 404 405 static int stripe_end_io(struct dm_target *ti, struct bio *bio, 406 blk_status_t *error) 407 { 408 unsigned i; 409 char major_minor[16]; 410 struct stripe_c *sc = ti->private; 411 412 if (!*error) 413 return DM_ENDIO_DONE; /* I/O complete */ 414 415 if (bio->bi_opf & REQ_RAHEAD) 416 return DM_ENDIO_DONE; 417 418 if (*error == BLK_STS_NOTSUPP) 419 return DM_ENDIO_DONE; 420 421 memset(major_minor, 0, sizeof(major_minor)); 422 sprintf(major_minor, "%d:%d", MAJOR(bio_dev(bio)), MINOR(bio_dev(bio))); 423 424 /* 425 * Test to see which stripe drive triggered the event 426 * and increment error count for all stripes on that device. 427 * If the error count for a given device exceeds the threshold 428 * value we will no longer trigger any further events. 429 */ 430 for (i = 0; i < sc->stripes; i++) 431 if (!strcmp(sc->stripe[i].dev->name, major_minor)) { 432 atomic_inc(&(sc->stripe[i].error_count)); 433 if (atomic_read(&(sc->stripe[i].error_count)) < 434 DM_IO_ERROR_THRESHOLD) 435 schedule_work(&sc->trigger_event); 436 } 437 438 return DM_ENDIO_DONE; 439 } 440 441 static int stripe_iterate_devices(struct dm_target *ti, 442 iterate_devices_callout_fn fn, void *data) 443 { 444 struct stripe_c *sc = ti->private; 445 int ret = 0; 446 unsigned i = 0; 447 448 do { 449 ret = fn(ti, sc->stripe[i].dev, 450 sc->stripe[i].physical_start, 451 sc->stripe_width, data); 452 } while (!ret && ++i < sc->stripes); 453 454 return ret; 455 } 456 457 static void stripe_io_hints(struct dm_target *ti, 458 struct queue_limits *limits) 459 { 460 struct stripe_c *sc = ti->private; 461 unsigned chunk_size = sc->chunk_size << SECTOR_SHIFT; 462 463 blk_limits_io_min(limits, chunk_size); 464 blk_limits_io_opt(limits, chunk_size * sc->stripes); 465 } 466 467 static struct target_type stripe_target = { 468 .name = "striped", 469 .version = {1, 6, 0}, 470 .features = DM_TARGET_PASSES_INTEGRITY, 471 .module = THIS_MODULE, 472 .ctr = stripe_ctr, 473 .dtr = stripe_dtr, 474 .map = stripe_map, 475 .end_io = stripe_end_io, 476 .status = stripe_status, 477 .iterate_devices = stripe_iterate_devices, 478 .io_hints = stripe_io_hints, 479 .direct_access = stripe_dax_direct_access, 480 .dax_copy_from_iter = stripe_dax_copy_from_iter, 481 }; 482 483 int __init dm_stripe_init(void) 484 { 485 int r; 486 487 r = dm_register_target(&stripe_target); 488 if (r < 0) 489 DMWARN("target registration failed"); 490 491 return r; 492 } 493 494 void dm_stripe_exit(void) 495 { 496 dm_unregister_target(&stripe_target); 497 } 498