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 sb_start; /* offset of the super block (in 512byte sectors) */ 59 int sb_size; /* bytes in the superblock */ 60 int preferred_minor; /* autorun support */ 61 62 struct kobject kobj; 63 64 /* A device can be in one of three states based on two flags: 65 * Not working: faulty==1 in_sync==0 66 * Fully working: faulty==0 in_sync==1 67 * Working, but not 68 * in sync with array 69 * faulty==0 in_sync==0 70 * 71 * It can never have faulty==1, in_sync==1 72 * This reduces the burden of testing multiple flags in many cases 73 */ 74 75 unsigned long flags; /* bit set of 'enum flag_bits' bits. */ 76 wait_queue_head_t blocked_wait; 77 78 int desc_nr; /* descriptor index in the superblock */ 79 int raid_disk; /* role of device in array */ 80 int new_raid_disk; /* role that the device will have in 81 * the array after a level-change completes. 82 */ 83 int saved_raid_disk; /* role that device used to have in the 84 * array and could again if we did a partial 85 * resync from the bitmap 86 */ 87 sector_t recovery_offset;/* If this device has been partially 88 * recovered, this is where we were 89 * up to. 90 */ 91 92 atomic_t nr_pending; /* number of pending requests. 93 * only maintained for arrays that 94 * support hot removal 95 */ 96 atomic_t read_errors; /* number of consecutive read errors that 97 * we have tried to ignore. 98 */ 99 struct timespec last_read_error; /* monotonic time since our 100 * last read error 101 */ 102 atomic_t corrected_errors; /* number of corrected read errors, 103 * for reporting to userspace and storing 104 * in superblock. 105 */ 106 struct work_struct del_work; /* used for delayed sysfs removal */ 107 108 struct sysfs_dirent *sysfs_state; /* handle for 'state' 109 * sysfs entry */ 110 111 struct badblocks { 112 int count; /* count of bad blocks */ 113 int unacked_exist; /* there probably are unacknowledged 114 * bad blocks. This is only cleared 115 * when a read discovers none 116 */ 117 int shift; /* shift from sectors to block size 118 * a -ve shift means badblocks are 119 * disabled.*/ 120 u64 *page; /* badblock list */ 121 int changed; 122 seqlock_t lock; 123 124 sector_t sector; 125 sector_t size; /* in sectors */ 126 } badblocks; 127 }; 128 enum flag_bits { 129 Faulty, /* device is known to have a fault */ 130 In_sync, /* device is in_sync with rest of array */ 131 Unmerged, /* device is being added to array and should 132 * be considerred for bvec_merge_fn but not 133 * yet for actual IO 134 */ 135 WriteMostly, /* Avoid reading if at all possible */ 136 AutoDetected, /* added by auto-detect */ 137 Blocked, /* An error occurred but has not yet 138 * been acknowledged by the metadata 139 * handler, so don't allow writes 140 * until it is cleared */ 141 WriteErrorSeen, /* A write error has been seen on this 142 * device 143 */ 144 FaultRecorded, /* Intermediate state for clearing 145 * Blocked. The Fault is/will-be 146 * recorded in the metadata, but that 147 * metadata hasn't been stored safely 148 * on disk yet. 149 */ 150 BlockedBadBlocks, /* A writer is blocked because they 151 * found an unacknowledged bad-block. 152 * This can safely be cleared at any 153 * time, and the writer will re-check. 154 * It may be set at any time, and at 155 * worst the writer will timeout and 156 * re-check. So setting it as 157 * accurately as possible is good, but 158 * not absolutely critical. 159 */ 160 WantReplacement, /* This device is a candidate to be 161 * hot-replaced, either because it has 162 * reported some faults, or because 163 * of explicit request. 164 */ 165 Replacement, /* This device is a replacement for 166 * a want_replacement device with same 167 * raid_disk number. 168 */ 169 }; 170 171 #define BB_LEN_MASK (0x00000000000001FFULL) 172 #define BB_OFFSET_MASK (0x7FFFFFFFFFFFFE00ULL) 173 #define BB_ACK_MASK (0x8000000000000000ULL) 174 #define BB_MAX_LEN 512 175 #define BB_OFFSET(x) (((x) & BB_OFFSET_MASK) >> 9) 176 #define BB_LEN(x) (((x) & BB_LEN_MASK) + 1) 177 #define BB_ACK(x) (!!((x) & BB_ACK_MASK)) 178 #define BB_MAKE(a, l, ack) (((a)<<9) | ((l)-1) | ((u64)(!!(ack)) << 63)) 179 180 extern int md_is_badblock(struct badblocks *bb, sector_t s, int sectors, 181 sector_t *first_bad, int *bad_sectors); 182 static inline int is_badblock(struct md_rdev *rdev, sector_t s, int sectors, 183 sector_t *first_bad, int *bad_sectors) 184 { 185 if (unlikely(rdev->badblocks.count)) { 186 int rv = md_is_badblock(&rdev->badblocks, rdev->data_offset + s, 187 sectors, 188 first_bad, bad_sectors); 189 if (rv) 190 *first_bad -= rdev->data_offset; 191 return rv; 192 } 193 return 0; 194 } 195 extern int rdev_set_badblocks(struct md_rdev *rdev, sector_t s, int sectors, 196 int acknowledged); 197 extern int rdev_clear_badblocks(struct md_rdev *rdev, sector_t s, int sectors); 198 extern void md_ack_all_badblocks(struct badblocks *bb); 199 200 struct mddev { 201 void *private; 202 struct md_personality *pers; 203 dev_t unit; 204 int md_minor; 205 struct list_head disks; 206 unsigned long flags; 207 #define MD_CHANGE_DEVS 0 /* Some device status has changed */ 208 #define MD_CHANGE_CLEAN 1 /* transition to or from 'clean' */ 209 #define MD_CHANGE_PENDING 2 /* switch from 'clean' to 'active' in progress */ 210 #define MD_ARRAY_FIRST_USE 3 /* First use of array, needs initialization */ 211 212 int suspended; 213 atomic_t active_io; 214 int ro; 215 int sysfs_active; /* set when sysfs deletes 216 * are happening, so run/ 217 * takeover/stop are not safe 218 */ 219 int ready; /* See when safe to pass 220 * IO requests down */ 221 struct gendisk *gendisk; 222 223 struct kobject kobj; 224 int hold_active; 225 #define UNTIL_IOCTL 1 226 #define UNTIL_STOP 2 227 228 /* Superblock information */ 229 int major_version, 230 minor_version, 231 patch_version; 232 int persistent; 233 int external; /* metadata is 234 * managed externally */ 235 char metadata_type[17]; /* externally set*/ 236 int chunk_sectors; 237 time_t ctime, utime; 238 int level, layout; 239 char clevel[16]; 240 int raid_disks; 241 int max_disks; 242 sector_t dev_sectors; /* used size of 243 * component devices */ 244 sector_t array_sectors; /* exported array size */ 245 int external_size; /* size managed 246 * externally */ 247 __u64 events; 248 /* If the last 'event' was simply a clean->dirty transition, and 249 * we didn't write it to the spares, then it is safe and simple 250 * to just decrement the event count on a dirty->clean transition. 251 * So we record that possibility here. 252 */ 253 int can_decrease_events; 254 255 char uuid[16]; 256 257 /* If the array is being reshaped, we need to record the 258 * new shape and an indication of where we are up to. 259 * This is written to the superblock. 260 * If reshape_position is MaxSector, then no reshape is happening (yet). 261 */ 262 sector_t reshape_position; 263 int delta_disks, new_level, new_layout; 264 int new_chunk_sectors; 265 266 atomic_t plug_cnt; /* If device is expecting 267 * more bios soon. 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 sector_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 * 311 * If neither SYNC or RESHAPE are set, then it is a recovery. 312 */ 313 #define MD_RECOVERY_RUNNING 0 314 #define MD_RECOVERY_SYNC 1 315 #define MD_RECOVERY_RECOVER 2 316 #define MD_RECOVERY_INTR 3 317 #define MD_RECOVERY_DONE 4 318 #define MD_RECOVERY_NEEDED 5 319 #define MD_RECOVERY_REQUESTED 6 320 #define MD_RECOVERY_CHECK 7 321 #define MD_RECOVERY_RESHAPE 8 322 #define MD_RECOVERY_FROZEN 9 323 324 unsigned long recovery; 325 /* If a RAID personality determines that recovery (of a particular 326 * device) will fail due to a read error on the source device, it 327 * takes a copy of this number and does not attempt recovery again 328 * until this number changes. 329 */ 330 int recovery_disabled; 331 332 int in_sync; /* know to not need resync */ 333 /* 'open_mutex' avoids races between 'md_open' and 'do_md_stop', so 334 * that we are never stopping an array while it is open. 335 * 'reconfig_mutex' protects all other reconfiguration. 336 * These locks are separate due to conflicting interactions 337 * with bdev->bd_mutex. 338 * Lock ordering is: 339 * reconfig_mutex -> bd_mutex : e.g. do_md_run -> revalidate_disk 340 * bd_mutex -> open_mutex: e.g. __blkdev_get -> md_open 341 */ 342 struct mutex open_mutex; 343 struct mutex reconfig_mutex; 344 atomic_t active; /* general refcount */ 345 atomic_t openers; /* number of active opens */ 346 347 int changed; /* True if we might need to 348 * reread partition info */ 349 int degraded; /* whether md should consider 350 * adding a spare 351 */ 352 int merge_check_needed; /* at least one 353 * member device 354 * has a 355 * merge_bvec_fn */ 356 357 atomic_t recovery_active; /* blocks scheduled, but not written */ 358 wait_queue_head_t recovery_wait; 359 sector_t recovery_cp; 360 sector_t resync_min; /* user requested sync 361 * starts here */ 362 sector_t resync_max; /* resync should pause 363 * when it gets here */ 364 365 struct sysfs_dirent *sysfs_state; /* handle for 'array_state' 366 * file in sysfs. 367 */ 368 struct sysfs_dirent *sysfs_action; /* handle for 'sync_action' */ 369 370 struct work_struct del_work; /* used for delayed sysfs removal */ 371 372 spinlock_t write_lock; 373 wait_queue_head_t sb_wait; /* for waiting on superblock updates */ 374 atomic_t pending_writes; /* number of active superblock writes */ 375 376 unsigned int safemode; /* if set, update "clean" superblock 377 * when no writes pending. 378 */ 379 unsigned int safemode_delay; 380 struct timer_list safemode_timer; 381 atomic_t writes_pending; 382 struct request_queue *queue; /* for plugging ... */ 383 384 struct bitmap *bitmap; /* the bitmap for the device */ 385 struct { 386 struct file *file; /* the bitmap file */ 387 loff_t offset; /* offset from superblock of 388 * start of bitmap. May be 389 * negative, but not '0' 390 * For external metadata, offset 391 * from start of device. 392 */ 393 loff_t default_offset; /* this is the offset to use when 394 * hot-adding a bitmap. It should 395 * eventually be settable by sysfs. 396 */ 397 struct mutex mutex; 398 unsigned long chunksize; 399 unsigned long daemon_sleep; /* how many jiffies between updates? */ 400 unsigned long max_write_behind; /* write-behind mode */ 401 int external; 402 } bitmap_info; 403 404 atomic_t max_corr_read_errors; /* max read retries */ 405 struct list_head all_mddevs; 406 407 struct attribute_group *to_remove; 408 409 struct bio_set *bio_set; 410 411 /* Generic flush handling. 412 * The last to finish preflush schedules a worker to submit 413 * the rest of the request (without the REQ_FLUSH flag). 414 */ 415 struct bio *flush_bio; 416 atomic_t flush_pending; 417 struct work_struct flush_work; 418 struct work_struct event_work; /* used by dm to report failure event */ 419 void (*sync_super)(struct mddev *mddev, struct md_rdev *rdev); 420 }; 421 422 423 static inline void rdev_dec_pending(struct md_rdev *rdev, struct mddev *mddev) 424 { 425 int faulty = test_bit(Faulty, &rdev->flags); 426 if (atomic_dec_and_test(&rdev->nr_pending) && faulty) 427 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); 428 } 429 430 static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors) 431 { 432 atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io); 433 } 434 435 struct md_personality 436 { 437 char *name; 438 int level; 439 struct list_head list; 440 struct module *owner; 441 void (*make_request)(struct mddev *mddev, struct bio *bio); 442 int (*run)(struct mddev *mddev); 443 int (*stop)(struct mddev *mddev); 444 void (*status)(struct seq_file *seq, struct mddev *mddev); 445 /* error_handler must set ->faulty and clear ->in_sync 446 * if appropriate, and should abort recovery if needed 447 */ 448 void (*error_handler)(struct mddev *mddev, struct md_rdev *rdev); 449 int (*hot_add_disk) (struct mddev *mddev, struct md_rdev *rdev); 450 int (*hot_remove_disk) (struct mddev *mddev, struct md_rdev *rdev); 451 int (*spare_active) (struct mddev *mddev); 452 sector_t (*sync_request)(struct mddev *mddev, sector_t sector_nr, int *skipped, int go_faster); 453 int (*resize) (struct mddev *mddev, sector_t sectors); 454 sector_t (*size) (struct mddev *mddev, sector_t sectors, int raid_disks); 455 int (*check_reshape) (struct mddev *mddev); 456 int (*start_reshape) (struct mddev *mddev); 457 void (*finish_reshape) (struct mddev *mddev); 458 /* quiesce moves between quiescence states 459 * 0 - fully active 460 * 1 - no new requests allowed 461 * others - reserved 462 */ 463 void (*quiesce) (struct mddev *mddev, int state); 464 /* takeover is used to transition an array from one 465 * personality to another. The new personality must be able 466 * to handle the data in the current layout. 467 * e.g. 2drive raid1 -> 2drive raid5 468 * ndrive raid5 -> degraded n+1drive raid6 with special layout 469 * If the takeover succeeds, a new 'private' structure is returned. 470 * This needs to be installed and then ->run used to activate the 471 * array. 472 */ 473 void *(*takeover) (struct mddev *mddev); 474 }; 475 476 477 struct md_sysfs_entry { 478 struct attribute attr; 479 ssize_t (*show)(struct mddev *, char *); 480 ssize_t (*store)(struct mddev *, const char *, size_t); 481 }; 482 extern struct attribute_group md_bitmap_group; 483 484 static inline struct sysfs_dirent *sysfs_get_dirent_safe(struct sysfs_dirent *sd, char *name) 485 { 486 if (sd) 487 return sysfs_get_dirent(sd, NULL, name); 488 return sd; 489 } 490 static inline void sysfs_notify_dirent_safe(struct sysfs_dirent *sd) 491 { 492 if (sd) 493 sysfs_notify_dirent(sd); 494 } 495 496 static inline char * mdname (struct mddev * mddev) 497 { 498 return mddev->gendisk ? mddev->gendisk->disk_name : "mdX"; 499 } 500 501 static inline int sysfs_link_rdev(struct mddev *mddev, struct md_rdev *rdev) 502 { 503 char nm[20]; 504 if (!test_bit(Replacement, &rdev->flags)) { 505 sprintf(nm, "rd%d", rdev->raid_disk); 506 return sysfs_create_link(&mddev->kobj, &rdev->kobj, nm); 507 } else 508 return 0; 509 } 510 511 static inline void sysfs_unlink_rdev(struct mddev *mddev, struct md_rdev *rdev) 512 { 513 char nm[20]; 514 if (!test_bit(Replacement, &rdev->flags)) { 515 sprintf(nm, "rd%d", rdev->raid_disk); 516 sysfs_remove_link(&mddev->kobj, nm); 517 } 518 } 519 520 /* 521 * iterates through some rdev ringlist. It's safe to remove the 522 * current 'rdev'. Dont touch 'tmp' though. 523 */ 524 #define rdev_for_each_list(rdev, tmp, head) \ 525 list_for_each_entry_safe(rdev, tmp, head, same_set) 526 527 /* 528 * iterates through the 'same array disks' ringlist 529 */ 530 #define rdev_for_each(rdev, mddev) \ 531 list_for_each_entry(rdev, &((mddev)->disks), same_set) 532 533 #define rdev_for_each_safe(rdev, tmp, mddev) \ 534 list_for_each_entry_safe(rdev, tmp, &((mddev)->disks), same_set) 535 536 #define rdev_for_each_rcu(rdev, mddev) \ 537 list_for_each_entry_rcu(rdev, &((mddev)->disks), same_set) 538 539 struct md_thread { 540 void (*run) (struct mddev *mddev); 541 struct mddev *mddev; 542 wait_queue_head_t wqueue; 543 unsigned long flags; 544 struct task_struct *tsk; 545 unsigned long timeout; 546 }; 547 548 #define THREAD_WAKEUP 0 549 550 #define __wait_event_lock_irq(wq, condition, lock, cmd) \ 551 do { \ 552 wait_queue_t __wait; \ 553 init_waitqueue_entry(&__wait, current); \ 554 \ 555 add_wait_queue(&wq, &__wait); \ 556 for (;;) { \ 557 set_current_state(TASK_UNINTERRUPTIBLE); \ 558 if (condition) \ 559 break; \ 560 spin_unlock_irq(&lock); \ 561 cmd; \ 562 schedule(); \ 563 spin_lock_irq(&lock); \ 564 } \ 565 current->state = TASK_RUNNING; \ 566 remove_wait_queue(&wq, &__wait); \ 567 } while (0) 568 569 #define wait_event_lock_irq(wq, condition, lock, cmd) \ 570 do { \ 571 if (condition) \ 572 break; \ 573 __wait_event_lock_irq(wq, condition, lock, cmd); \ 574 } while (0) 575 576 static inline void safe_put_page(struct page *p) 577 { 578 if (p) put_page(p); 579 } 580 581 extern int register_md_personality(struct md_personality *p); 582 extern int unregister_md_personality(struct md_personality *p); 583 extern struct md_thread *md_register_thread( 584 void (*run)(struct mddev *mddev), 585 struct mddev *mddev, 586 const char *name); 587 extern void md_unregister_thread(struct md_thread **threadp); 588 extern void md_wakeup_thread(struct md_thread *thread); 589 extern void md_check_recovery(struct mddev *mddev); 590 extern void md_write_start(struct mddev *mddev, struct bio *bi); 591 extern void md_write_end(struct mddev *mddev); 592 extern void md_done_sync(struct mddev *mddev, int blocks, int ok); 593 extern void md_error(struct mddev *mddev, struct md_rdev *rdev); 594 595 extern int mddev_congested(struct mddev *mddev, int bits); 596 extern void md_flush_request(struct mddev *mddev, struct bio *bio); 597 extern void md_super_write(struct mddev *mddev, struct md_rdev *rdev, 598 sector_t sector, int size, struct page *page); 599 extern void md_super_wait(struct mddev *mddev); 600 extern int sync_page_io(struct md_rdev *rdev, sector_t sector, int size, 601 struct page *page, int rw, bool metadata_op); 602 extern void md_do_sync(struct mddev *mddev); 603 extern void md_new_event(struct mddev *mddev); 604 extern int md_allow_write(struct mddev *mddev); 605 extern void md_wait_for_blocked_rdev(struct md_rdev *rdev, struct mddev *mddev); 606 extern void md_set_array_sectors(struct mddev *mddev, sector_t array_sectors); 607 extern int md_check_no_bitmap(struct mddev *mddev); 608 extern int md_integrity_register(struct mddev *mddev); 609 extern void md_integrity_add_rdev(struct md_rdev *rdev, struct mddev *mddev); 610 extern int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale); 611 extern void restore_bitmap_write_access(struct file *file); 612 613 extern void mddev_init(struct mddev *mddev); 614 extern int md_run(struct mddev *mddev); 615 extern void md_stop(struct mddev *mddev); 616 extern void md_stop_writes(struct mddev *mddev); 617 extern int md_rdev_init(struct md_rdev *rdev); 618 619 extern void mddev_suspend(struct mddev *mddev); 620 extern void mddev_resume(struct mddev *mddev); 621 extern struct bio *bio_clone_mddev(struct bio *bio, gfp_t gfp_mask, 622 struct mddev *mddev); 623 extern struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs, 624 struct mddev *mddev); 625 extern int mddev_check_plugged(struct mddev *mddev); 626 extern void md_trim_bio(struct bio *bio, int offset, int size); 627 #endif /* _MD_MD_H */ 628