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