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