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 29typedef struct mddev_s mddev_t; 30typedef struct mdk_rdev_s mdk_rdev_t; 31 32/* generic plugging support - like that provided with request_queue, 33 * but does not require a request_queue 34 */ 35struct plug_handle { 36 void (*unplug_fn)(struct plug_handle *); 37 struct timer_list unplug_timer; 38 struct work_struct unplug_work; 39 unsigned long unplug_flag; 40}; 41#define PLUGGED_FLAG 1 42void plugger_init(struct plug_handle *plug, 43 void (*unplug_fn)(struct plug_handle *)); 44void plugger_set_plug(struct plug_handle *plug); 45int plugger_remove_plug(struct plug_handle *plug); 46static inline void plugger_flush(struct plug_handle *plug) 47{ 48 del_timer_sync(&plug->unplug_timer); 49 cancel_work_sync(&plug->unplug_work); 50} 51 52/* 53 * MD's 'extended' device 54 */ 55struct mdk_rdev_s 56{ 57 struct list_head same_set; /* RAID devices within the same set */ 58 59 sector_t sectors; /* Device size (in 512bytes sectors) */ 60 mddev_t *mddev; /* RAID array if running */ 61 int last_events; /* IO event timestamp */ 62 63 struct block_device *bdev; /* block device handle */ 64 65 struct page *sb_page; 66 int sb_loaded; 67 __u64 sb_events; 68 sector_t data_offset; /* start of data in array */ 69 sector_t sb_start; /* offset of the super block (in 512byte sectors) */ 70 int sb_size; /* bytes in the superblock */ 71 int preferred_minor; /* autorun support */ 72 73 struct kobject kobj; 74 75 /* A device can be in one of three states based on two flags: 76 * Not working: faulty==1 in_sync==0 77 * Fully working: faulty==0 in_sync==1 78 * Working, but not 79 * in sync with array 80 * faulty==0 in_sync==0 81 * 82 * It can never have faulty==1, in_sync==1 83 * This reduces the burden of testing multiple flags in many cases 84 */ 85 86 unsigned long flags; 87#define Faulty 1 /* device is known to have a fault */ 88#define In_sync 2 /* device is in_sync with rest of array */ 89#define WriteMostly 4 /* Avoid reading if at all possible */ 90#define BarriersNotsupp 5 /* REQ_HARDBARRIER is not supported */ 91#define AllReserved 6 /* If whole device is reserved for 92 * one array */ 93#define AutoDetected 7 /* added by auto-detect */ 94#define Blocked 8 /* An error occured on an externally 95 * managed array, don't allow writes 96 * until it is cleared */ 97 wait_queue_head_t blocked_wait; 98 99 int desc_nr; /* descriptor index in the superblock */ 100 int raid_disk; /* role of device in array */ 101 int new_raid_disk; /* role that the device will have in 102 * the array after a level-change completes. 103 */ 104 int saved_raid_disk; /* role that device used to have in the 105 * array and could again if we did a partial 106 * resync from the bitmap 107 */ 108 sector_t recovery_offset;/* If this device has been partially 109 * recovered, this is where we were 110 * up to. 111 */ 112 113 atomic_t nr_pending; /* number of pending requests. 114 * only maintained for arrays that 115 * support hot removal 116 */ 117 atomic_t read_errors; /* number of consecutive read errors that 118 * we have tried to ignore. 119 */ 120 struct timespec last_read_error; /* monotonic time since our 121 * last read error 122 */ 123 atomic_t corrected_errors; /* number of corrected read errors, 124 * for reporting to userspace and storing 125 * in superblock. 126 */ 127 struct work_struct del_work; /* used for delayed sysfs removal */ 128 129 struct sysfs_dirent *sysfs_state; /* handle for 'state' 130 * sysfs entry */ 131}; 132 133struct mddev_s 134{ 135 void *private; 136 struct mdk_personality *pers; 137 dev_t unit; 138 int md_minor; 139 struct list_head disks; 140 unsigned long flags; 141#define MD_CHANGE_DEVS 0 /* Some device status has changed */ 142#define MD_CHANGE_CLEAN 1 /* transition to or from 'clean' */ 143#define MD_CHANGE_PENDING 2 /* switch from 'clean' to 'active' in progress */ 144 145 int suspended; 146 atomic_t active_io; 147 int ro; 148 int sysfs_active; /* set when sysfs deletes 149 * are happening, so run/ 150 * takeover/stop are not safe 151 */ 152 int ready; /* See when safe to pass 153 * IO requests down */ 154 struct gendisk *gendisk; 155 156 struct kobject kobj; 157 int hold_active; 158#define UNTIL_IOCTL 1 159#define UNTIL_STOP 2 160 161 /* Superblock information */ 162 int major_version, 163 minor_version, 164 patch_version; 165 int persistent; 166 int external; /* metadata is 167 * managed externally */ 168 char metadata_type[17]; /* externally set*/ 169 int chunk_sectors; 170 time_t ctime, utime; 171 int level, layout; 172 char clevel[16]; 173 int raid_disks; 174 int max_disks; 175 sector_t dev_sectors; /* used size of 176 * component devices */ 177 sector_t array_sectors; /* exported array size */ 178 int external_size; /* size managed 179 * externally */ 180 __u64 events; 181 /* If the last 'event' was simply a clean->dirty transition, and 182 * we didn't write it to the spares, then it is safe and simple 183 * to just decrement the event count on a dirty->clean transition. 184 * So we record that possibility here. 185 */ 186 int can_decrease_events; 187 188 char uuid[16]; 189 190 /* If the array is being reshaped, we need to record the 191 * new shape and an indication of where we are up to. 192 * This is written to the superblock. 193 * If reshape_position is MaxSector, then no reshape is happening (yet). 194 */ 195 sector_t reshape_position; 196 int delta_disks, new_level, new_layout; 197 int new_chunk_sectors; 198 199 struct mdk_thread_s *thread; /* management thread */ 200 struct mdk_thread_s *sync_thread; /* doing resync or reconstruct */ 201 sector_t curr_resync; /* last block scheduled */ 202 /* As resync requests can complete out of order, we cannot easily track 203 * how much resync has been completed. So we occasionally pause until 204 * everything completes, then set curr_resync_completed to curr_resync. 205 * As such it may be well behind the real resync mark, but it is a value 206 * we are certain of. 207 */ 208 sector_t curr_resync_completed; 209 unsigned long resync_mark; /* a recent timestamp */ 210 sector_t resync_mark_cnt;/* blocks written at resync_mark */ 211 sector_t curr_mark_cnt; /* blocks scheduled now */ 212 213 sector_t resync_max_sectors; /* may be set by personality */ 214 215 sector_t resync_mismatches; /* count of sectors where 216 * parity/replica mismatch found 217 */ 218 219 /* allow user-space to request suspension of IO to regions of the array */ 220 sector_t suspend_lo; 221 sector_t suspend_hi; 222 /* if zero, use the system-wide default */ 223 int sync_speed_min; 224 int sync_speed_max; 225 226 /* resync even though the same disks are shared among md-devices */ 227 int parallel_resync; 228 229 int ok_start_degraded; 230 /* recovery/resync flags 231 * NEEDED: we might need to start a resync/recover 232 * RUNNING: a thread is running, or about to be started 233 * SYNC: actually doing a resync, not a recovery 234 * RECOVER: doing recovery, or need to try it. 235 * INTR: resync needs to be aborted for some reason 236 * DONE: thread is done and is waiting to be reaped 237 * REQUEST: user-space has requested a sync (used with SYNC) 238 * CHECK: user-space request for check-only, no repair 239 * RESHAPE: A reshape is happening 240 * 241 * If neither SYNC or RESHAPE are set, then it is a recovery. 242 */ 243#define MD_RECOVERY_RUNNING 0 244#define MD_RECOVERY_SYNC 1 245#define MD_RECOVERY_RECOVER 2 246#define MD_RECOVERY_INTR 3 247#define MD_RECOVERY_DONE 4 248#define MD_RECOVERY_NEEDED 5 249#define MD_RECOVERY_REQUESTED 6 250#define MD_RECOVERY_CHECK 7 251#define MD_RECOVERY_RESHAPE 8 252#define MD_RECOVERY_FROZEN 9 253 254 unsigned long recovery; 255 int recovery_disabled; /* if we detect that recovery 256 * will always fail, set this 257 * so we don't loop trying */ 258 259 int in_sync; /* know to not need resync */ 260 /* 'open_mutex' avoids races between 'md_open' and 'do_md_stop', so 261 * that we are never stopping an array while it is open. 262 * 'reconfig_mutex' protects all other reconfiguration. 263 * These locks are separate due to conflicting interactions 264 * with bdev->bd_mutex. 265 * Lock ordering is: 266 * reconfig_mutex -> bd_mutex : e.g. do_md_run -> revalidate_disk 267 * bd_mutex -> open_mutex: e.g. __blkdev_get -> md_open 268 */ 269 struct mutex open_mutex; 270 struct mutex reconfig_mutex; 271 atomic_t active; /* general refcount */ 272 atomic_t openers; /* number of active opens */ 273 274 int degraded; /* whether md should consider 275 * adding a spare 276 */ 277 int barriers_work; /* initialised to true, cleared as soon 278 * as a barrier request to slave 279 * fails. Only supported 280 */ 281 struct bio *biolist; /* bios that need to be retried 282 * because REQ_HARDBARRIER is not supported 283 */ 284 285 atomic_t recovery_active; /* blocks scheduled, but not written */ 286 wait_queue_head_t recovery_wait; 287 sector_t recovery_cp; 288 sector_t resync_min; /* user requested sync 289 * starts here */ 290 sector_t resync_max; /* resync should pause 291 * when it gets here */ 292 293 struct sysfs_dirent *sysfs_state; /* handle for 'array_state' 294 * file in sysfs. 295 */ 296 struct sysfs_dirent *sysfs_action; /* handle for 'sync_action' */ 297 298 struct work_struct del_work; /* used for delayed sysfs removal */ 299 300 spinlock_t write_lock; 301 wait_queue_head_t sb_wait; /* for waiting on superblock updates */ 302 atomic_t pending_writes; /* number of active superblock writes */ 303 304 unsigned int safemode; /* if set, update "clean" superblock 305 * when no writes pending. 306 */ 307 unsigned int safemode_delay; 308 struct timer_list safemode_timer; 309 atomic_t writes_pending; 310 struct request_queue *queue; /* for plugging ... */ 311 312 struct bitmap *bitmap; /* the bitmap for the device */ 313 struct { 314 struct file *file; /* the bitmap file */ 315 loff_t offset; /* offset from superblock of 316 * start of bitmap. May be 317 * negative, but not '0' 318 * For external metadata, offset 319 * from start of device. 320 */ 321 loff_t default_offset; /* this is the offset to use when 322 * hot-adding a bitmap. It should 323 * eventually be settable by sysfs. 324 */ 325 /* When md is serving under dm, it might use a 326 * dirty_log to store the bits. 327 */ 328 struct dm_dirty_log *log; 329 330 struct mutex mutex; 331 unsigned long chunksize; 332 unsigned long daemon_sleep; /* how many jiffies between updates? */ 333 unsigned long max_write_behind; /* write-behind mode */ 334 int external; 335 } bitmap_info; 336 337 atomic_t max_corr_read_errors; /* max read retries */ 338 struct list_head all_mddevs; 339 340 struct attribute_group *to_remove; 341 struct plug_handle *plug; /* if used by personality */ 342 343 /* Generic barrier handling. 344 * If there is a pending barrier request, all other 345 * writes are blocked while the devices are flushed. 346 * The last to finish a flush schedules a worker to 347 * submit the barrier request (without the barrier flag), 348 * then submit more flush requests. 349 */ 350 struct bio *barrier; 351 atomic_t flush_pending; 352 struct work_struct barrier_work; 353 struct work_struct event_work; /* used by dm to report failure event */ 354}; 355 356 357static inline void rdev_dec_pending(mdk_rdev_t *rdev, mddev_t *mddev) 358{ 359 int faulty = test_bit(Faulty, &rdev->flags); 360 if (atomic_dec_and_test(&rdev->nr_pending) && faulty) 361 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); 362} 363 364static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors) 365{ 366 atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io); 367} 368 369struct mdk_personality 370{ 371 char *name; 372 int level; 373 struct list_head list; 374 struct module *owner; 375 int (*make_request)(mddev_t *mddev, struct bio *bio); 376 int (*run)(mddev_t *mddev); 377 int (*stop)(mddev_t *mddev); 378 void (*status)(struct seq_file *seq, mddev_t *mddev); 379 /* error_handler must set ->faulty and clear ->in_sync 380 * if appropriate, and should abort recovery if needed 381 */ 382 void (*error_handler)(mddev_t *mddev, mdk_rdev_t *rdev); 383 int (*hot_add_disk) (mddev_t *mddev, mdk_rdev_t *rdev); 384 int (*hot_remove_disk) (mddev_t *mddev, int number); 385 int (*spare_active) (mddev_t *mddev); 386 sector_t (*sync_request)(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster); 387 int (*resize) (mddev_t *mddev, sector_t sectors); 388 sector_t (*size) (mddev_t *mddev, sector_t sectors, int raid_disks); 389 int (*check_reshape) (mddev_t *mddev); 390 int (*start_reshape) (mddev_t *mddev); 391 void (*finish_reshape) (mddev_t *mddev); 392 /* quiesce moves between quiescence states 393 * 0 - fully active 394 * 1 - no new requests allowed 395 * others - reserved 396 */ 397 void (*quiesce) (mddev_t *mddev, int state); 398 /* takeover is used to transition an array from one 399 * personality to another. The new personality must be able 400 * to handle the data in the current layout. 401 * e.g. 2drive raid1 -> 2drive raid5 402 * ndrive raid5 -> degraded n+1drive raid6 with special layout 403 * If the takeover succeeds, a new 'private' structure is returned. 404 * This needs to be installed and then ->run used to activate the 405 * array. 406 */ 407 void *(*takeover) (mddev_t *mddev); 408}; 409 410 411struct md_sysfs_entry { 412 struct attribute attr; 413 ssize_t (*show)(mddev_t *, char *); 414 ssize_t (*store)(mddev_t *, const char *, size_t); 415}; 416extern struct attribute_group md_bitmap_group; 417 418static inline struct sysfs_dirent *sysfs_get_dirent_safe(struct sysfs_dirent *sd, char *name) 419{ 420 if (sd) 421 return sysfs_get_dirent(sd, NULL, name); 422 return sd; 423} 424static inline void sysfs_notify_dirent_safe(struct sysfs_dirent *sd) 425{ 426 if (sd) 427 sysfs_notify_dirent(sd); 428} 429 430static inline char * mdname (mddev_t * mddev) 431{ 432 return mddev->gendisk ? mddev->gendisk->disk_name : "mdX"; 433} 434 435/* 436 * iterates through some rdev ringlist. It's safe to remove the 437 * current 'rdev'. Dont touch 'tmp' though. 438 */ 439#define rdev_for_each_list(rdev, tmp, head) \ 440 list_for_each_entry_safe(rdev, tmp, head, same_set) 441 442/* 443 * iterates through the 'same array disks' ringlist 444 */ 445#define rdev_for_each(rdev, tmp, mddev) \ 446 list_for_each_entry_safe(rdev, tmp, &((mddev)->disks), same_set) 447 448#define rdev_for_each_rcu(rdev, mddev) \ 449 list_for_each_entry_rcu(rdev, &((mddev)->disks), same_set) 450 451typedef struct mdk_thread_s { 452 void (*run) (mddev_t *mddev); 453 mddev_t *mddev; 454 wait_queue_head_t wqueue; 455 unsigned long flags; 456 struct task_struct *tsk; 457 unsigned long timeout; 458} mdk_thread_t; 459 460#define THREAD_WAKEUP 0 461 462#define __wait_event_lock_irq(wq, condition, lock, cmd) \ 463do { \ 464 wait_queue_t __wait; \ 465 init_waitqueue_entry(&__wait, current); \ 466 \ 467 add_wait_queue(&wq, &__wait); \ 468 for (;;) { \ 469 set_current_state(TASK_UNINTERRUPTIBLE); \ 470 if (condition) \ 471 break; \ 472 spin_unlock_irq(&lock); \ 473 cmd; \ 474 schedule(); \ 475 spin_lock_irq(&lock); \ 476 } \ 477 current->state = TASK_RUNNING; \ 478 remove_wait_queue(&wq, &__wait); \ 479} while (0) 480 481#define wait_event_lock_irq(wq, condition, lock, cmd) \ 482do { \ 483 if (condition) \ 484 break; \ 485 __wait_event_lock_irq(wq, condition, lock, cmd); \ 486} while (0) 487 488static inline void safe_put_page(struct page *p) 489{ 490 if (p) put_page(p); 491} 492 493extern int register_md_personality(struct mdk_personality *p); 494extern int unregister_md_personality(struct mdk_personality *p); 495extern mdk_thread_t * md_register_thread(void (*run) (mddev_t *mddev), 496 mddev_t *mddev, const char *name); 497extern void md_unregister_thread(mdk_thread_t *thread); 498extern void md_wakeup_thread(mdk_thread_t *thread); 499extern void md_check_recovery(mddev_t *mddev); 500extern void md_write_start(mddev_t *mddev, struct bio *bi); 501extern void md_write_end(mddev_t *mddev); 502extern void md_done_sync(mddev_t *mddev, int blocks, int ok); 503extern void md_error(mddev_t *mddev, mdk_rdev_t *rdev); 504 505extern int mddev_congested(mddev_t *mddev, int bits); 506extern void md_barrier_request(mddev_t *mddev, struct bio *bio); 507extern void md_super_write(mddev_t *mddev, mdk_rdev_t *rdev, 508 sector_t sector, int size, struct page *page); 509extern void md_super_wait(mddev_t *mddev); 510extern int sync_page_io(struct block_device *bdev, sector_t sector, int size, 511 struct page *page, int rw); 512extern void md_do_sync(mddev_t *mddev); 513extern void md_new_event(mddev_t *mddev); 514extern int md_allow_write(mddev_t *mddev); 515extern void md_wait_for_blocked_rdev(mdk_rdev_t *rdev, mddev_t *mddev); 516extern void md_set_array_sectors(mddev_t *mddev, sector_t array_sectors); 517extern int md_check_no_bitmap(mddev_t *mddev); 518extern int md_integrity_register(mddev_t *mddev); 519extern void md_integrity_add_rdev(mdk_rdev_t *rdev, mddev_t *mddev); 520extern int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale); 521extern void restore_bitmap_write_access(struct file *file); 522extern void md_unplug(mddev_t *mddev); 523 524extern void mddev_init(mddev_t *mddev); 525extern int md_run(mddev_t *mddev); 526extern void md_stop(mddev_t *mddev); 527extern void md_stop_writes(mddev_t *mddev); 528extern void md_rdev_init(mdk_rdev_t *rdev); 529 530extern void mddev_suspend(mddev_t *mddev); 531extern void mddev_resume(mddev_t *mddev); 532#endif /* _MD_MD_H */ 533