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 WriteMostly, /* Avoid reading if at all possible */ 132 AutoDetected, /* added by auto-detect */ 133 Blocked, /* An error occurred but has not yet 134 * been acknowledged by the metadata 135 * handler, so don't allow writes 136 * until it is cleared */ 137 WriteErrorSeen, /* A write error has been seen on this 138 * device 139 */ 140 FaultRecorded, /* Intermediate state for clearing 141 * Blocked. The Fault is/will-be 142 * recorded in the metadata, but that 143 * metadata hasn't been stored safely 144 * on disk yet. 145 */ 146 BlockedBadBlocks, /* A writer is blocked because they 147 * found an unacknowledged bad-block. 148 * This can safely be cleared at any 149 * time, and the writer will re-check. 150 * It may be set at any time, and at 151 * worst the writer will timeout and 152 * re-check. So setting it as 153 * accurately as possible is good, but 154 * not absolutely critical. 155 */ 156 WantReplacement, /* This device is a candidate to be 157 * hot-replaced, either because it has 158 * reported some faults, or because 159 * of explicit request. 160 */ 161 Replacement, /* This device is a replacement for 162 * a want_replacement device with same 163 * raid_disk number. 164 */ 165 }; 166 167 #define BB_LEN_MASK (0x00000000000001FFULL) 168 #define BB_OFFSET_MASK (0x7FFFFFFFFFFFFE00ULL) 169 #define BB_ACK_MASK (0x8000000000000000ULL) 170 #define BB_MAX_LEN 512 171 #define BB_OFFSET(x) (((x) & BB_OFFSET_MASK) >> 9) 172 #define BB_LEN(x) (((x) & BB_LEN_MASK) + 1) 173 #define BB_ACK(x) (!!((x) & BB_ACK_MASK)) 174 #define BB_MAKE(a, l, ack) (((a)<<9) | ((l)-1) | ((u64)(!!(ack)) << 63)) 175 176 extern int md_is_badblock(struct badblocks *bb, sector_t s, int sectors, 177 sector_t *first_bad, int *bad_sectors); 178 static inline int is_badblock(struct md_rdev *rdev, sector_t s, int sectors, 179 sector_t *first_bad, int *bad_sectors) 180 { 181 if (unlikely(rdev->badblocks.count)) { 182 int rv = md_is_badblock(&rdev->badblocks, rdev->data_offset + s, 183 sectors, 184 first_bad, bad_sectors); 185 if (rv) 186 *first_bad -= rdev->data_offset; 187 return rv; 188 } 189 return 0; 190 } 191 extern int rdev_set_badblocks(struct md_rdev *rdev, sector_t s, int sectors, 192 int acknowledged); 193 extern int rdev_clear_badblocks(struct md_rdev *rdev, sector_t s, int sectors); 194 extern void md_ack_all_badblocks(struct badblocks *bb); 195 196 struct mddev { 197 void *private; 198 struct md_personality *pers; 199 dev_t unit; 200 int md_minor; 201 struct list_head disks; 202 unsigned long flags; 203 #define MD_CHANGE_DEVS 0 /* Some device status has changed */ 204 #define MD_CHANGE_CLEAN 1 /* transition to or from 'clean' */ 205 #define MD_CHANGE_PENDING 2 /* switch from 'clean' to 'active' in progress */ 206 #define MD_ARRAY_FIRST_USE 3 /* First use of array, needs initialization */ 207 208 int suspended; 209 atomic_t active_io; 210 int ro; 211 int sysfs_active; /* set when sysfs deletes 212 * are happening, so run/ 213 * takeover/stop are not safe 214 */ 215 int ready; /* See when safe to pass 216 * IO requests down */ 217 struct gendisk *gendisk; 218 219 struct kobject kobj; 220 int hold_active; 221 #define UNTIL_IOCTL 1 222 #define UNTIL_STOP 2 223 224 /* Superblock information */ 225 int major_version, 226 minor_version, 227 patch_version; 228 int persistent; 229 int external; /* metadata is 230 * managed externally */ 231 char metadata_type[17]; /* externally set*/ 232 int chunk_sectors; 233 time_t ctime, utime; 234 int level, layout; 235 char clevel[16]; 236 int raid_disks; 237 int max_disks; 238 sector_t dev_sectors; /* used size of 239 * component devices */ 240 sector_t array_sectors; /* exported array size */ 241 int external_size; /* size managed 242 * externally */ 243 __u64 events; 244 /* If the last 'event' was simply a clean->dirty transition, and 245 * we didn't write it to the spares, then it is safe and simple 246 * to just decrement the event count on a dirty->clean transition. 247 * So we record that possibility here. 248 */ 249 int can_decrease_events; 250 251 char uuid[16]; 252 253 /* If the array is being reshaped, we need to record the 254 * new shape and an indication of where we are up to. 255 * This is written to the superblock. 256 * If reshape_position is MaxSector, then no reshape is happening (yet). 257 */ 258 sector_t reshape_position; 259 int delta_disks, new_level, new_layout; 260 int new_chunk_sectors; 261 262 atomic_t plug_cnt; /* If device is expecting 263 * more bios soon. 264 */ 265 struct md_thread *thread; /* management thread */ 266 struct md_thread *sync_thread; /* doing resync or reconstruct */ 267 sector_t curr_resync; /* last block scheduled */ 268 /* As resync requests can complete out of order, we cannot easily track 269 * how much resync has been completed. So we occasionally pause until 270 * everything completes, then set curr_resync_completed to curr_resync. 271 * As such it may be well behind the real resync mark, but it is a value 272 * we are certain of. 273 */ 274 sector_t curr_resync_completed; 275 unsigned long resync_mark; /* a recent timestamp */ 276 sector_t resync_mark_cnt;/* blocks written at resync_mark */ 277 sector_t curr_mark_cnt; /* blocks scheduled now */ 278 279 sector_t resync_max_sectors; /* may be set by personality */ 280 281 sector_t resync_mismatches; /* count of sectors where 282 * parity/replica mismatch found 283 */ 284 285 /* allow user-space to request suspension of IO to regions of the array */ 286 sector_t suspend_lo; 287 sector_t suspend_hi; 288 /* if zero, use the system-wide default */ 289 int sync_speed_min; 290 int sync_speed_max; 291 292 /* resync even though the same disks are shared among md-devices */ 293 int parallel_resync; 294 295 int ok_start_degraded; 296 /* recovery/resync flags 297 * NEEDED: we might need to start a resync/recover 298 * RUNNING: a thread is running, or about to be started 299 * SYNC: actually doing a resync, not a recovery 300 * RECOVER: doing recovery, or need to try it. 301 * INTR: resync needs to be aborted for some reason 302 * DONE: thread is done and is waiting to be reaped 303 * REQUEST: user-space has requested a sync (used with SYNC) 304 * CHECK: user-space request for check-only, no repair 305 * RESHAPE: A reshape is happening 306 * 307 * If neither SYNC or RESHAPE are set, then it is a recovery. 308 */ 309 #define MD_RECOVERY_RUNNING 0 310 #define MD_RECOVERY_SYNC 1 311 #define MD_RECOVERY_RECOVER 2 312 #define MD_RECOVERY_INTR 3 313 #define MD_RECOVERY_DONE 4 314 #define MD_RECOVERY_NEEDED 5 315 #define MD_RECOVERY_REQUESTED 6 316 #define MD_RECOVERY_CHECK 7 317 #define MD_RECOVERY_RESHAPE 8 318 #define MD_RECOVERY_FROZEN 9 319 320 unsigned long recovery; 321 /* If a RAID personality determines that recovery (of a particular 322 * device) will fail due to a read error on the source device, it 323 * takes a copy of this number and does not attempt recovery again 324 * until this number changes. 325 */ 326 int recovery_disabled; 327 328 int in_sync; /* know to not need resync */ 329 /* 'open_mutex' avoids races between 'md_open' and 'do_md_stop', so 330 * that we are never stopping an array while it is open. 331 * 'reconfig_mutex' protects all other reconfiguration. 332 * These locks are separate due to conflicting interactions 333 * with bdev->bd_mutex. 334 * Lock ordering is: 335 * reconfig_mutex -> bd_mutex : e.g. do_md_run -> revalidate_disk 336 * bd_mutex -> open_mutex: e.g. __blkdev_get -> md_open 337 */ 338 struct mutex open_mutex; 339 struct mutex reconfig_mutex; 340 atomic_t active; /* general refcount */ 341 atomic_t openers; /* number of active opens */ 342 343 int changed; /* True if we might need to 344 * reread partition info */ 345 int degraded; /* whether md should consider 346 * adding a spare 347 */ 348 349 atomic_t recovery_active; /* blocks scheduled, but not written */ 350 wait_queue_head_t recovery_wait; 351 sector_t recovery_cp; 352 sector_t resync_min; /* user requested sync 353 * starts here */ 354 sector_t resync_max; /* resync should pause 355 * when it gets here */ 356 357 struct sysfs_dirent *sysfs_state; /* handle for 'array_state' 358 * file in sysfs. 359 */ 360 struct sysfs_dirent *sysfs_action; /* handle for 'sync_action' */ 361 362 struct work_struct del_work; /* used for delayed sysfs removal */ 363 364 spinlock_t write_lock; 365 wait_queue_head_t sb_wait; /* for waiting on superblock updates */ 366 atomic_t pending_writes; /* number of active superblock writes */ 367 368 unsigned int safemode; /* if set, update "clean" superblock 369 * when no writes pending. 370 */ 371 unsigned int safemode_delay; 372 struct timer_list safemode_timer; 373 atomic_t writes_pending; 374 struct request_queue *queue; /* for plugging ... */ 375 376 struct bitmap *bitmap; /* the bitmap for the device */ 377 struct { 378 struct file *file; /* the bitmap file */ 379 loff_t offset; /* offset from superblock of 380 * start of bitmap. May be 381 * negative, but not '0' 382 * For external metadata, offset 383 * from start of device. 384 */ 385 loff_t default_offset; /* this is the offset to use when 386 * hot-adding a bitmap. It should 387 * eventually be settable by sysfs. 388 */ 389 struct mutex mutex; 390 unsigned long chunksize; 391 unsigned long daemon_sleep; /* how many jiffies between updates? */ 392 unsigned long max_write_behind; /* write-behind mode */ 393 int external; 394 } bitmap_info; 395 396 atomic_t max_corr_read_errors; /* max read retries */ 397 struct list_head all_mddevs; 398 399 struct attribute_group *to_remove; 400 401 struct bio_set *bio_set; 402 403 /* Generic flush handling. 404 * The last to finish preflush schedules a worker to submit 405 * the rest of the request (without the REQ_FLUSH flag). 406 */ 407 struct bio *flush_bio; 408 atomic_t flush_pending; 409 struct work_struct flush_work; 410 struct work_struct event_work; /* used by dm to report failure event */ 411 void (*sync_super)(struct mddev *mddev, struct md_rdev *rdev); 412 }; 413 414 415 static inline void rdev_dec_pending(struct md_rdev *rdev, struct mddev *mddev) 416 { 417 int faulty = test_bit(Faulty, &rdev->flags); 418 if (atomic_dec_and_test(&rdev->nr_pending) && faulty) 419 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); 420 } 421 422 static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors) 423 { 424 atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io); 425 } 426 427 struct md_personality 428 { 429 char *name; 430 int level; 431 struct list_head list; 432 struct module *owner; 433 void (*make_request)(struct mddev *mddev, struct bio *bio); 434 int (*run)(struct mddev *mddev); 435 int (*stop)(struct mddev *mddev); 436 void (*status)(struct seq_file *seq, struct mddev *mddev); 437 /* error_handler must set ->faulty and clear ->in_sync 438 * if appropriate, and should abort recovery if needed 439 */ 440 void (*error_handler)(struct mddev *mddev, struct md_rdev *rdev); 441 int (*hot_add_disk) (struct mddev *mddev, struct md_rdev *rdev); 442 int (*hot_remove_disk) (struct mddev *mddev, struct md_rdev *rdev); 443 int (*spare_active) (struct mddev *mddev); 444 sector_t (*sync_request)(struct mddev *mddev, sector_t sector_nr, int *skipped, int go_faster); 445 int (*resize) (struct mddev *mddev, sector_t sectors); 446 sector_t (*size) (struct mddev *mddev, sector_t sectors, int raid_disks); 447 int (*check_reshape) (struct mddev *mddev); 448 int (*start_reshape) (struct mddev *mddev); 449 void (*finish_reshape) (struct mddev *mddev); 450 /* quiesce moves between quiescence states 451 * 0 - fully active 452 * 1 - no new requests allowed 453 * others - reserved 454 */ 455 void (*quiesce) (struct mddev *mddev, int state); 456 /* takeover is used to transition an array from one 457 * personality to another. The new personality must be able 458 * to handle the data in the current layout. 459 * e.g. 2drive raid1 -> 2drive raid5 460 * ndrive raid5 -> degraded n+1drive raid6 with special layout 461 * If the takeover succeeds, a new 'private' structure is returned. 462 * This needs to be installed and then ->run used to activate the 463 * array. 464 */ 465 void *(*takeover) (struct mddev *mddev); 466 }; 467 468 469 struct md_sysfs_entry { 470 struct attribute attr; 471 ssize_t (*show)(struct mddev *, char *); 472 ssize_t (*store)(struct mddev *, const char *, size_t); 473 }; 474 extern struct attribute_group md_bitmap_group; 475 476 static inline struct sysfs_dirent *sysfs_get_dirent_safe(struct sysfs_dirent *sd, char *name) 477 { 478 if (sd) 479 return sysfs_get_dirent(sd, NULL, name); 480 return sd; 481 } 482 static inline void sysfs_notify_dirent_safe(struct sysfs_dirent *sd) 483 { 484 if (sd) 485 sysfs_notify_dirent(sd); 486 } 487 488 static inline char * mdname (struct mddev * mddev) 489 { 490 return mddev->gendisk ? mddev->gendisk->disk_name : "mdX"; 491 } 492 493 static inline int sysfs_link_rdev(struct mddev *mddev, struct md_rdev *rdev) 494 { 495 char nm[20]; 496 if (!test_bit(Replacement, &rdev->flags)) { 497 sprintf(nm, "rd%d", rdev->raid_disk); 498 return sysfs_create_link(&mddev->kobj, &rdev->kobj, nm); 499 } else 500 return 0; 501 } 502 503 static inline void sysfs_unlink_rdev(struct mddev *mddev, struct md_rdev *rdev) 504 { 505 char nm[20]; 506 if (!test_bit(Replacement, &rdev->flags)) { 507 sprintf(nm, "rd%d", rdev->raid_disk); 508 sysfs_remove_link(&mddev->kobj, nm); 509 } 510 } 511 512 /* 513 * iterates through some rdev ringlist. It's safe to remove the 514 * current 'rdev'. Dont touch 'tmp' though. 515 */ 516 #define rdev_for_each_list(rdev, tmp, head) \ 517 list_for_each_entry_safe(rdev, tmp, head, same_set) 518 519 /* 520 * iterates through the 'same array disks' ringlist 521 */ 522 #define rdev_for_each(rdev, tmp, mddev) \ 523 list_for_each_entry_safe(rdev, tmp, &((mddev)->disks), same_set) 524 525 #define rdev_for_each_rcu(rdev, mddev) \ 526 list_for_each_entry_rcu(rdev, &((mddev)->disks), same_set) 527 528 struct md_thread { 529 void (*run) (struct mddev *mddev); 530 struct mddev *mddev; 531 wait_queue_head_t wqueue; 532 unsigned long flags; 533 struct task_struct *tsk; 534 unsigned long timeout; 535 }; 536 537 #define THREAD_WAKEUP 0 538 539 #define __wait_event_lock_irq(wq, condition, lock, cmd) \ 540 do { \ 541 wait_queue_t __wait; \ 542 init_waitqueue_entry(&__wait, current); \ 543 \ 544 add_wait_queue(&wq, &__wait); \ 545 for (;;) { \ 546 set_current_state(TASK_UNINTERRUPTIBLE); \ 547 if (condition) \ 548 break; \ 549 spin_unlock_irq(&lock); \ 550 cmd; \ 551 schedule(); \ 552 spin_lock_irq(&lock); \ 553 } \ 554 current->state = TASK_RUNNING; \ 555 remove_wait_queue(&wq, &__wait); \ 556 } while (0) 557 558 #define wait_event_lock_irq(wq, condition, lock, cmd) \ 559 do { \ 560 if (condition) \ 561 break; \ 562 __wait_event_lock_irq(wq, condition, lock, cmd); \ 563 } while (0) 564 565 static inline void safe_put_page(struct page *p) 566 { 567 if (p) put_page(p); 568 } 569 570 extern int register_md_personality(struct md_personality *p); 571 extern int unregister_md_personality(struct md_personality *p); 572 extern struct md_thread *md_register_thread( 573 void (*run)(struct mddev *mddev), 574 struct mddev *mddev, 575 const char *name); 576 extern void md_unregister_thread(struct md_thread **threadp); 577 extern void md_wakeup_thread(struct md_thread *thread); 578 extern void md_check_recovery(struct mddev *mddev); 579 extern void md_write_start(struct mddev *mddev, struct bio *bi); 580 extern void md_write_end(struct mddev *mddev); 581 extern void md_done_sync(struct mddev *mddev, int blocks, int ok); 582 extern void md_error(struct mddev *mddev, struct md_rdev *rdev); 583 584 extern int mddev_congested(struct mddev *mddev, int bits); 585 extern void md_flush_request(struct mddev *mddev, struct bio *bio); 586 extern void md_super_write(struct mddev *mddev, struct md_rdev *rdev, 587 sector_t sector, int size, struct page *page); 588 extern void md_super_wait(struct mddev *mddev); 589 extern int sync_page_io(struct md_rdev *rdev, sector_t sector, int size, 590 struct page *page, int rw, bool metadata_op); 591 extern void md_do_sync(struct mddev *mddev); 592 extern void md_new_event(struct mddev *mddev); 593 extern int md_allow_write(struct mddev *mddev); 594 extern void md_wait_for_blocked_rdev(struct md_rdev *rdev, struct mddev *mddev); 595 extern void md_set_array_sectors(struct mddev *mddev, sector_t array_sectors); 596 extern int md_check_no_bitmap(struct mddev *mddev); 597 extern int md_integrity_register(struct mddev *mddev); 598 extern void md_integrity_add_rdev(struct md_rdev *rdev, struct mddev *mddev); 599 extern int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale); 600 extern void restore_bitmap_write_access(struct file *file); 601 602 extern void mddev_init(struct mddev *mddev); 603 extern int md_run(struct mddev *mddev); 604 extern void md_stop(struct mddev *mddev); 605 extern void md_stop_writes(struct mddev *mddev); 606 extern int md_rdev_init(struct md_rdev *rdev); 607 608 extern void mddev_suspend(struct mddev *mddev); 609 extern void mddev_resume(struct mddev *mddev); 610 extern struct bio *bio_clone_mddev(struct bio *bio, gfp_t gfp_mask, 611 struct mddev *mddev); 612 extern struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs, 613 struct mddev *mddev); 614 extern int mddev_check_plugged(struct mddev *mddev); 615 extern void md_trim_bio(struct bio *bio, int offset, int size); 616 #endif /* _MD_MD_H */ 617