1 /* 2 md.h : kernel internal structure of the Linux MD driver 3 Copyright (C) 1996-98 Ingo Molnar, Gadi Oxman 4 5 This program is free software; you can redistribute it and/or modify 6 it under the terms of the GNU General Public License as published by 7 the Free Software Foundation; either version 2, or (at your option) 8 any later version. 9 10 You should have received a copy of the GNU General Public License 11 (for example /usr/src/linux/COPYING); if not, write to the Free 12 Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 13 */ 14 15 #ifndef _MD_MD_H 16 #define _MD_MD_H 17 18 #include <linux/blkdev.h> 19 #include <linux/kobject.h> 20 #include <linux/list.h> 21 #include <linux/mm.h> 22 #include <linux/mutex.h> 23 #include <linux/timer.h> 24 #include <linux/wait.h> 25 #include <linux/workqueue.h> 26 27 #define MaxSector (~(sector_t)0) 28 29 /* Bad block numbers are stored sorted in a single page. 30 * 64bits is used for each block or extent. 31 * 54 bits are sector number, 9 bits are extent size, 32 * 1 bit is an 'acknowledged' flag. 33 */ 34 #define MD_MAX_BADBLOCKS (PAGE_SIZE/8) 35 36 /* 37 * MD's 'extended' device 38 */ 39 struct md_rdev { 40 struct list_head same_set; /* RAID devices within the same set */ 41 42 sector_t sectors; /* Device size (in 512bytes sectors) */ 43 struct mddev *mddev; /* RAID array if running */ 44 int last_events; /* IO event timestamp */ 45 46 /* 47 * If meta_bdev is non-NULL, it means that a separate device is 48 * being used to store the metadata (superblock/bitmap) which 49 * would otherwise be contained on the same device as the data (bdev). 50 */ 51 struct block_device *meta_bdev; 52 struct block_device *bdev; /* block device handle */ 53 54 struct page *sb_page, *bb_page; 55 int sb_loaded; 56 __u64 sb_events; 57 sector_t data_offset; /* start of data in array */ 58 sector_t new_data_offset;/* only relevant while reshaping */ 59 sector_t sb_start; /* offset of the super block (in 512byte sectors) */ 60 int sb_size; /* bytes in the superblock */ 61 int preferred_minor; /* autorun support */ 62 63 struct kobject kobj; 64 65 /* A device can be in one of three states based on two flags: 66 * Not working: faulty==1 in_sync==0 67 * Fully working: faulty==0 in_sync==1 68 * Working, but not 69 * in sync with array 70 * faulty==0 in_sync==0 71 * 72 * It can never have faulty==1, in_sync==1 73 * This reduces the burden of testing multiple flags in many cases 74 */ 75 76 unsigned long flags; /* bit set of 'enum flag_bits' bits. */ 77 wait_queue_head_t blocked_wait; 78 79 int desc_nr; /* descriptor index in the superblock */ 80 int raid_disk; /* role of device in array */ 81 int new_raid_disk; /* role that the device will have in 82 * the array after a level-change completes. 83 */ 84 int saved_raid_disk; /* role that device used to have in the 85 * array and could again if we did a partial 86 * resync from the bitmap 87 */ 88 sector_t recovery_offset;/* If this device has been partially 89 * recovered, this is where we were 90 * up to. 91 */ 92 93 atomic_t nr_pending; /* number of pending requests. 94 * only maintained for arrays that 95 * support hot removal 96 */ 97 atomic_t read_errors; /* number of consecutive read errors that 98 * we have tried to ignore. 99 */ 100 struct timespec last_read_error; /* monotonic time since our 101 * last read error 102 */ 103 atomic_t corrected_errors; /* number of corrected read errors, 104 * for reporting to userspace and storing 105 * in superblock. 106 */ 107 struct work_struct del_work; /* used for delayed sysfs removal */ 108 109 struct sysfs_dirent *sysfs_state; /* handle for 'state' 110 * sysfs entry */ 111 112 struct badblocks { 113 int count; /* count of bad blocks */ 114 int unacked_exist; /* there probably are unacknowledged 115 * bad blocks. This is only cleared 116 * when a read discovers none 117 */ 118 int shift; /* shift from sectors to block size 119 * a -ve shift means badblocks are 120 * disabled.*/ 121 u64 *page; /* badblock list */ 122 int changed; 123 seqlock_t lock; 124 125 sector_t sector; 126 sector_t size; /* in sectors */ 127 } badblocks; 128 }; 129 enum flag_bits { 130 Faulty, /* device is known to have a fault */ 131 In_sync, /* device is in_sync with rest of array */ 132 Unmerged, /* device is being added to array and should 133 * be considerred for bvec_merge_fn but not 134 * yet for actual IO 135 */ 136 WriteMostly, /* Avoid reading if at all possible */ 137 AutoDetected, /* added by auto-detect */ 138 Blocked, /* An error occurred but has not yet 139 * been acknowledged by the metadata 140 * handler, so don't allow writes 141 * until it is cleared */ 142 WriteErrorSeen, /* A write error has been seen on this 143 * device 144 */ 145 FaultRecorded, /* Intermediate state for clearing 146 * Blocked. The Fault is/will-be 147 * recorded in the metadata, but that 148 * metadata hasn't been stored safely 149 * on disk yet. 150 */ 151 BlockedBadBlocks, /* A writer is blocked because they 152 * found an unacknowledged bad-block. 153 * This can safely be cleared at any 154 * time, and the writer will re-check. 155 * It may be set at any time, and at 156 * worst the writer will timeout and 157 * re-check. So setting it as 158 * accurately as possible is good, but 159 * not absolutely critical. 160 */ 161 WantReplacement, /* This device is a candidate to be 162 * hot-replaced, either because it has 163 * reported some faults, or because 164 * of explicit request. 165 */ 166 Replacement, /* This device is a replacement for 167 * a want_replacement device with same 168 * raid_disk number. 169 */ 170 }; 171 172 #define BB_LEN_MASK (0x00000000000001FFULL) 173 #define BB_OFFSET_MASK (0x7FFFFFFFFFFFFE00ULL) 174 #define BB_ACK_MASK (0x8000000000000000ULL) 175 #define BB_MAX_LEN 512 176 #define BB_OFFSET(x) (((x) & BB_OFFSET_MASK) >> 9) 177 #define BB_LEN(x) (((x) & BB_LEN_MASK) + 1) 178 #define BB_ACK(x) (!!((x) & BB_ACK_MASK)) 179 #define BB_MAKE(a, l, ack) (((a)<<9) | ((l)-1) | ((u64)(!!(ack)) << 63)) 180 181 extern int md_is_badblock(struct badblocks *bb, sector_t s, int sectors, 182 sector_t *first_bad, int *bad_sectors); 183 static inline int is_badblock(struct md_rdev *rdev, sector_t s, int sectors, 184 sector_t *first_bad, int *bad_sectors) 185 { 186 if (unlikely(rdev->badblocks.count)) { 187 int rv = md_is_badblock(&rdev->badblocks, rdev->data_offset + s, 188 sectors, 189 first_bad, bad_sectors); 190 if (rv) 191 *first_bad -= rdev->data_offset; 192 return rv; 193 } 194 return 0; 195 } 196 extern int rdev_set_badblocks(struct md_rdev *rdev, sector_t s, int sectors, 197 int is_new); 198 extern int rdev_clear_badblocks(struct md_rdev *rdev, sector_t s, int sectors, 199 int is_new); 200 extern void md_ack_all_badblocks(struct badblocks *bb); 201 202 struct mddev { 203 void *private; 204 struct md_personality *pers; 205 dev_t unit; 206 int md_minor; 207 struct list_head disks; 208 unsigned long flags; 209 #define MD_CHANGE_DEVS 0 /* Some device status has changed */ 210 #define MD_CHANGE_CLEAN 1 /* transition to or from 'clean' */ 211 #define MD_CHANGE_PENDING 2 /* switch from 'clean' to 'active' in progress */ 212 #define MD_ARRAY_FIRST_USE 3 /* First use of array, needs initialization */ 213 214 int suspended; 215 atomic_t active_io; 216 int ro; 217 int sysfs_active; /* set when sysfs deletes 218 * are happening, so run/ 219 * takeover/stop are not safe 220 */ 221 int ready; /* See when safe to pass 222 * IO requests down */ 223 struct gendisk *gendisk; 224 225 struct kobject kobj; 226 int hold_active; 227 #define UNTIL_IOCTL 1 228 #define UNTIL_STOP 2 229 230 /* Superblock information */ 231 int major_version, 232 minor_version, 233 patch_version; 234 int persistent; 235 int external; /* metadata is 236 * managed externally */ 237 char metadata_type[17]; /* externally set*/ 238 int chunk_sectors; 239 time_t ctime, utime; 240 int level, layout; 241 char clevel[16]; 242 int raid_disks; 243 int max_disks; 244 sector_t dev_sectors; /* used size of 245 * component devices */ 246 sector_t array_sectors; /* exported array size */ 247 int external_size; /* size managed 248 * externally */ 249 __u64 events; 250 /* If the last 'event' was simply a clean->dirty transition, and 251 * we didn't write it to the spares, then it is safe and simple 252 * to just decrement the event count on a dirty->clean transition. 253 * So we record that possibility here. 254 */ 255 int can_decrease_events; 256 257 char uuid[16]; 258 259 /* If the array is being reshaped, we need to record the 260 * new shape and an indication of where we are up to. 261 * This is written to the superblock. 262 * If reshape_position is MaxSector, then no reshape is happening (yet). 263 */ 264 sector_t reshape_position; 265 int delta_disks, new_level, new_layout; 266 int new_chunk_sectors; 267 int reshape_backwards; 268 269 struct md_thread *thread; /* management thread */ 270 struct md_thread *sync_thread; /* doing resync or reconstruct */ 271 sector_t curr_resync; /* last block scheduled */ 272 /* As resync requests can complete out of order, we cannot easily track 273 * how much resync has been completed. So we occasionally pause until 274 * everything completes, then set curr_resync_completed to curr_resync. 275 * As such it may be well behind the real resync mark, but it is a value 276 * we are certain of. 277 */ 278 sector_t curr_resync_completed; 279 unsigned long resync_mark; /* a recent timestamp */ 280 sector_t resync_mark_cnt;/* blocks written at resync_mark */ 281 sector_t curr_mark_cnt; /* blocks scheduled now */ 282 283 sector_t resync_max_sectors; /* may be set by personality */ 284 285 atomic64_t resync_mismatches; /* count of sectors where 286 * parity/replica mismatch found 287 */ 288 289 /* allow user-space to request suspension of IO to regions of the array */ 290 sector_t suspend_lo; 291 sector_t suspend_hi; 292 /* if zero, use the system-wide default */ 293 int sync_speed_min; 294 int sync_speed_max; 295 296 /* resync even though the same disks are shared among md-devices */ 297 int parallel_resync; 298 299 int ok_start_degraded; 300 /* recovery/resync flags 301 * NEEDED: we might need to start a resync/recover 302 * RUNNING: a thread is running, or about to be started 303 * SYNC: actually doing a resync, not a recovery 304 * RECOVER: doing recovery, or need to try it. 305 * INTR: resync needs to be aborted for some reason 306 * DONE: thread is done and is waiting to be reaped 307 * REQUEST: user-space has requested a sync (used with SYNC) 308 * CHECK: user-space request for check-only, no repair 309 * RESHAPE: A reshape is happening 310 * ERROR: sync-action interrupted because io-error 311 * 312 * If neither SYNC or RESHAPE are set, then it is a recovery. 313 */ 314 #define MD_RECOVERY_RUNNING 0 315 #define MD_RECOVERY_SYNC 1 316 #define MD_RECOVERY_RECOVER 2 317 #define MD_RECOVERY_INTR 3 318 #define MD_RECOVERY_DONE 4 319 #define MD_RECOVERY_NEEDED 5 320 #define MD_RECOVERY_REQUESTED 6 321 #define MD_RECOVERY_CHECK 7 322 #define MD_RECOVERY_RESHAPE 8 323 #define MD_RECOVERY_FROZEN 9 324 #define MD_RECOVERY_ERROR 10 325 326 unsigned long recovery; 327 /* If a RAID personality determines that recovery (of a particular 328 * device) will fail due to a read error on the source device, it 329 * takes a copy of this number and does not attempt recovery again 330 * until this number changes. 331 */ 332 int recovery_disabled; 333 334 int in_sync; /* know to not need resync */ 335 /* 'open_mutex' avoids races between 'md_open' and 'do_md_stop', so 336 * that we are never stopping an array while it is open. 337 * 'reconfig_mutex' protects all other reconfiguration. 338 * These locks are separate due to conflicting interactions 339 * with bdev->bd_mutex. 340 * Lock ordering is: 341 * reconfig_mutex -> bd_mutex : e.g. do_md_run -> revalidate_disk 342 * bd_mutex -> open_mutex: e.g. __blkdev_get -> md_open 343 */ 344 struct mutex open_mutex; 345 struct mutex reconfig_mutex; 346 atomic_t active; /* general refcount */ 347 atomic_t openers; /* number of active opens */ 348 349 int changed; /* True if we might need to 350 * reread partition info */ 351 int degraded; /* whether md should consider 352 * adding a spare 353 */ 354 int merge_check_needed; /* at least one 355 * member device 356 * has a 357 * merge_bvec_fn */ 358 359 atomic_t recovery_active; /* blocks scheduled, but not written */ 360 wait_queue_head_t recovery_wait; 361 sector_t recovery_cp; 362 sector_t resync_min; /* user requested sync 363 * starts here */ 364 sector_t resync_max; /* resync should pause 365 * when it gets here */ 366 367 struct sysfs_dirent *sysfs_state; /* handle for 'array_state' 368 * file in sysfs. 369 */ 370 struct sysfs_dirent *sysfs_action; /* handle for 'sync_action' */ 371 372 struct work_struct del_work; /* used for delayed sysfs removal */ 373 374 spinlock_t write_lock; 375 wait_queue_head_t sb_wait; /* for waiting on superblock updates */ 376 atomic_t pending_writes; /* number of active superblock writes */ 377 378 unsigned int safemode; /* if set, update "clean" superblock 379 * when no writes pending. 380 */ 381 unsigned int safemode_delay; 382 struct timer_list safemode_timer; 383 atomic_t writes_pending; 384 struct request_queue *queue; /* for plugging ... */ 385 386 struct bitmap *bitmap; /* the bitmap for the device */ 387 struct { 388 struct file *file; /* the bitmap file */ 389 loff_t offset; /* offset from superblock of 390 * start of bitmap. May be 391 * negative, but not '0' 392 * For external metadata, offset 393 * from start of device. 394 */ 395 unsigned long space; /* space available at this offset */ 396 loff_t default_offset; /* this is the offset to use when 397 * hot-adding a bitmap. It should 398 * eventually be settable by sysfs. 399 */ 400 unsigned long default_space; /* space available at 401 * default offset */ 402 struct mutex mutex; 403 unsigned long chunksize; 404 unsigned long daemon_sleep; /* how many jiffies between updates? */ 405 unsigned long max_write_behind; /* write-behind mode */ 406 int external; 407 } bitmap_info; 408 409 atomic_t max_corr_read_errors; /* max read retries */ 410 struct list_head all_mddevs; 411 412 struct attribute_group *to_remove; 413 414 struct bio_set *bio_set; 415 416 /* Generic flush handling. 417 * The last to finish preflush schedules a worker to submit 418 * the rest of the request (without the REQ_FLUSH flag). 419 */ 420 struct bio *flush_bio; 421 atomic_t flush_pending; 422 struct work_struct flush_work; 423 struct work_struct event_work; /* used by dm to report failure event */ 424 void (*sync_super)(struct mddev *mddev, struct md_rdev *rdev); 425 }; 426 427 428 static inline void rdev_dec_pending(struct md_rdev *rdev, struct mddev *mddev) 429 { 430 int faulty = test_bit(Faulty, &rdev->flags); 431 if (atomic_dec_and_test(&rdev->nr_pending) && faulty) 432 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); 433 } 434 435 static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors) 436 { 437 atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io); 438 } 439 440 struct md_personality 441 { 442 char *name; 443 int level; 444 struct list_head list; 445 struct module *owner; 446 void (*make_request)(struct mddev *mddev, struct bio *bio); 447 int (*run)(struct mddev *mddev); 448 int (*stop)(struct mddev *mddev); 449 void (*status)(struct seq_file *seq, struct mddev *mddev); 450 /* error_handler must set ->faulty and clear ->in_sync 451 * if appropriate, and should abort recovery if needed 452 */ 453 void (*error_handler)(struct mddev *mddev, struct md_rdev *rdev); 454 int (*hot_add_disk) (struct mddev *mddev, struct md_rdev *rdev); 455 int (*hot_remove_disk) (struct mddev *mddev, struct md_rdev *rdev); 456 int (*spare_active) (struct mddev *mddev); 457 sector_t (*sync_request)(struct mddev *mddev, sector_t sector_nr, int *skipped, int go_faster); 458 int (*resize) (struct mddev *mddev, sector_t sectors); 459 sector_t (*size) (struct mddev *mddev, sector_t sectors, int raid_disks); 460 int (*check_reshape) (struct mddev *mddev); 461 int (*start_reshape) (struct mddev *mddev); 462 void (*finish_reshape) (struct mddev *mddev); 463 /* quiesce moves between quiescence states 464 * 0 - fully active 465 * 1 - no new requests allowed 466 * others - reserved 467 */ 468 void (*quiesce) (struct mddev *mddev, int state); 469 /* takeover is used to transition an array from one 470 * personality to another. The new personality must be able 471 * to handle the data in the current layout. 472 * e.g. 2drive raid1 -> 2drive raid5 473 * ndrive raid5 -> degraded n+1drive raid6 with special layout 474 * If the takeover succeeds, a new 'private' structure is returned. 475 * This needs to be installed and then ->run used to activate the 476 * array. 477 */ 478 void *(*takeover) (struct mddev *mddev); 479 }; 480 481 482 struct md_sysfs_entry { 483 struct attribute attr; 484 ssize_t (*show)(struct mddev *, char *); 485 ssize_t (*store)(struct mddev *, const char *, size_t); 486 }; 487 extern struct attribute_group md_bitmap_group; 488 489 static inline struct sysfs_dirent *sysfs_get_dirent_safe(struct sysfs_dirent *sd, char *name) 490 { 491 if (sd) 492 return sysfs_get_dirent(sd, NULL, name); 493 return sd; 494 } 495 static inline void sysfs_notify_dirent_safe(struct sysfs_dirent *sd) 496 { 497 if (sd) 498 sysfs_notify_dirent(sd); 499 } 500 501 static inline char * mdname (struct mddev * mddev) 502 { 503 return mddev->gendisk ? mddev->gendisk->disk_name : "mdX"; 504 } 505 506 static inline int sysfs_link_rdev(struct mddev *mddev, struct md_rdev *rdev) 507 { 508 char nm[20]; 509 if (!test_bit(Replacement, &rdev->flags)) { 510 sprintf(nm, "rd%d", rdev->raid_disk); 511 return sysfs_create_link(&mddev->kobj, &rdev->kobj, nm); 512 } else 513 return 0; 514 } 515 516 static inline void sysfs_unlink_rdev(struct mddev *mddev, struct md_rdev *rdev) 517 { 518 char nm[20]; 519 if (!test_bit(Replacement, &rdev->flags)) { 520 sprintf(nm, "rd%d", rdev->raid_disk); 521 sysfs_remove_link(&mddev->kobj, nm); 522 } 523 } 524 525 /* 526 * iterates through some rdev ringlist. It's safe to remove the 527 * current 'rdev'. Dont touch 'tmp' though. 528 */ 529 #define rdev_for_each_list(rdev, tmp, head) \ 530 list_for_each_entry_safe(rdev, tmp, head, same_set) 531 532 /* 533 * iterates through the 'same array disks' ringlist 534 */ 535 #define rdev_for_each(rdev, mddev) \ 536 list_for_each_entry(rdev, &((mddev)->disks), same_set) 537 538 #define rdev_for_each_safe(rdev, tmp, mddev) \ 539 list_for_each_entry_safe(rdev, tmp, &((mddev)->disks), same_set) 540 541 #define rdev_for_each_rcu(rdev, mddev) \ 542 list_for_each_entry_rcu(rdev, &((mddev)->disks), same_set) 543 544 struct md_thread { 545 void (*run) (struct md_thread *thread); 546 struct mddev *mddev; 547 wait_queue_head_t wqueue; 548 unsigned long flags; 549 struct task_struct *tsk; 550 unsigned long timeout; 551 void *private; 552 }; 553 554 #define THREAD_WAKEUP 0 555 556 static inline void safe_put_page(struct page *p) 557 { 558 if (p) put_page(p); 559 } 560 561 extern int register_md_personality(struct md_personality *p); 562 extern int unregister_md_personality(struct md_personality *p); 563 extern struct md_thread *md_register_thread( 564 void (*run)(struct md_thread *thread), 565 struct mddev *mddev, 566 const char *name); 567 extern void md_unregister_thread(struct md_thread **threadp); 568 extern void md_wakeup_thread(struct md_thread *thread); 569 extern void md_check_recovery(struct mddev *mddev); 570 extern void md_write_start(struct mddev *mddev, struct bio *bi); 571 extern void md_write_end(struct mddev *mddev); 572 extern void md_done_sync(struct mddev *mddev, int blocks, int ok); 573 extern void md_error(struct mddev *mddev, struct md_rdev *rdev); 574 extern void md_finish_reshape(struct mddev *mddev); 575 576 extern int mddev_congested(struct mddev *mddev, int bits); 577 extern void md_flush_request(struct mddev *mddev, struct bio *bio); 578 extern void md_super_write(struct mddev *mddev, struct md_rdev *rdev, 579 sector_t sector, int size, struct page *page); 580 extern void md_super_wait(struct mddev *mddev); 581 extern int sync_page_io(struct md_rdev *rdev, sector_t sector, int size, 582 struct page *page, int rw, bool metadata_op); 583 extern void md_do_sync(struct md_thread *thread); 584 extern void md_new_event(struct mddev *mddev); 585 extern int md_allow_write(struct mddev *mddev); 586 extern void md_wait_for_blocked_rdev(struct md_rdev *rdev, struct mddev *mddev); 587 extern void md_set_array_sectors(struct mddev *mddev, sector_t array_sectors); 588 extern int md_check_no_bitmap(struct mddev *mddev); 589 extern int md_integrity_register(struct mddev *mddev); 590 extern void md_integrity_add_rdev(struct md_rdev *rdev, struct mddev *mddev); 591 extern int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale); 592 extern void restore_bitmap_write_access(struct file *file); 593 594 extern void mddev_init(struct mddev *mddev); 595 extern int md_run(struct mddev *mddev); 596 extern void md_stop(struct mddev *mddev); 597 extern void md_stop_writes(struct mddev *mddev); 598 extern int md_rdev_init(struct md_rdev *rdev); 599 extern void md_rdev_clear(struct md_rdev *rdev); 600 601 extern void mddev_suspend(struct mddev *mddev); 602 extern void mddev_resume(struct mddev *mddev); 603 extern struct bio *bio_clone_mddev(struct bio *bio, gfp_t gfp_mask, 604 struct mddev *mddev); 605 extern struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs, 606 struct mddev *mddev); 607 extern void md_trim_bio(struct bio *bio, int offset, int size); 608 609 extern void md_unplug(struct blk_plug_cb *cb, bool from_schedule); 610 static inline int mddev_check_plugged(struct mddev *mddev) 611 { 612 return !!blk_check_plugged(md_unplug, mddev, 613 sizeof(struct blk_plug_cb)); 614 } 615 #endif /* _MD_MD_H */ 616