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