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 #define StateChanged 9 /* Faulty or Blocked has changed during 78 * interrupt, so it needs to be 79 * notified by the thread */ 80 wait_queue_head_t blocked_wait; 81 82 int desc_nr; /* descriptor index in the superblock */ 83 int raid_disk; /* role of device in array */ 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 atomic_t corrected_errors; /* number of corrected read errors, 101 * for reporting to userspace and storing 102 * in superblock. 103 */ 104 struct work_struct del_work; /* used for delayed sysfs removal */ 105 106 struct sysfs_dirent *sysfs_state; /* handle for 'state' 107 * sysfs entry */ 108 }; 109 110 struct mddev_s 111 { 112 void *private; 113 struct mdk_personality *pers; 114 dev_t unit; 115 int md_minor; 116 struct list_head disks; 117 unsigned long flags; 118 #define MD_CHANGE_DEVS 0 /* Some device status has changed */ 119 #define MD_CHANGE_CLEAN 1 /* transition to or from 'clean' */ 120 #define MD_CHANGE_PENDING 2 /* superblock update in progress */ 121 122 int suspended; 123 atomic_t active_io; 124 int ro; 125 126 struct gendisk *gendisk; 127 128 struct kobject kobj; 129 int hold_active; 130 #define UNTIL_IOCTL 1 131 #define UNTIL_STOP 2 132 133 /* Superblock information */ 134 int major_version, 135 minor_version, 136 patch_version; 137 int persistent; 138 int external; /* metadata is 139 * managed externally */ 140 char metadata_type[17]; /* externally set*/ 141 int chunk_sectors; 142 time_t ctime, utime; 143 int level, layout; 144 char clevel[16]; 145 int raid_disks; 146 int max_disks; 147 sector_t dev_sectors; /* used size of 148 * component devices */ 149 sector_t array_sectors; /* exported array size */ 150 int external_size; /* size managed 151 * externally */ 152 __u64 events; 153 154 char uuid[16]; 155 156 /* If the array is being reshaped, we need to record the 157 * new shape and an indication of where we are up to. 158 * This is written to the superblock. 159 * If reshape_position is MaxSector, then no reshape is happening (yet). 160 */ 161 sector_t reshape_position; 162 int delta_disks, new_level, new_layout; 163 int new_chunk_sectors; 164 165 struct mdk_thread_s *thread; /* management thread */ 166 struct mdk_thread_s *sync_thread; /* doing resync or reconstruct */ 167 sector_t curr_resync; /* last block scheduled */ 168 /* As resync requests can complete out of order, we cannot easily track 169 * how much resync has been completed. So we occasionally pause until 170 * everything completes, then set curr_resync_completed to curr_resync. 171 * As such it may be well behind the real resync mark, but it is a value 172 * we are certain of. 173 */ 174 sector_t curr_resync_completed; 175 unsigned long resync_mark; /* a recent timestamp */ 176 sector_t resync_mark_cnt;/* blocks written at resync_mark */ 177 sector_t curr_mark_cnt; /* blocks scheduled now */ 178 179 sector_t resync_max_sectors; /* may be set by personality */ 180 181 sector_t resync_mismatches; /* count of sectors where 182 * parity/replica mismatch found 183 */ 184 185 /* allow user-space to request suspension of IO to regions of the array */ 186 sector_t suspend_lo; 187 sector_t suspend_hi; 188 /* if zero, use the system-wide default */ 189 int sync_speed_min; 190 int sync_speed_max; 191 192 /* resync even though the same disks are shared among md-devices */ 193 int parallel_resync; 194 195 int ok_start_degraded; 196 /* recovery/resync flags 197 * NEEDED: we might need to start a resync/recover 198 * RUNNING: a thread is running, or about to be started 199 * SYNC: actually doing a resync, not a recovery 200 * RECOVER: doing recovery, or need to try it. 201 * INTR: resync needs to be aborted for some reason 202 * DONE: thread is done and is waiting to be reaped 203 * REQUEST: user-space has requested a sync (used with SYNC) 204 * CHECK: user-space request for check-only, no repair 205 * RESHAPE: A reshape is happening 206 * 207 * If neither SYNC or RESHAPE are set, then it is a recovery. 208 */ 209 #define MD_RECOVERY_RUNNING 0 210 #define MD_RECOVERY_SYNC 1 211 #define MD_RECOVERY_RECOVER 2 212 #define MD_RECOVERY_INTR 3 213 #define MD_RECOVERY_DONE 4 214 #define MD_RECOVERY_NEEDED 5 215 #define MD_RECOVERY_REQUESTED 6 216 #define MD_RECOVERY_CHECK 7 217 #define MD_RECOVERY_RESHAPE 8 218 #define MD_RECOVERY_FROZEN 9 219 220 unsigned long recovery; 221 int recovery_disabled; /* if we detect that recovery 222 * will always fail, set this 223 * so we don't loop trying */ 224 225 int in_sync; /* know to not need resync */ 226 /* 'open_mutex' avoids races between 'md_open' and 'do_md_stop', so 227 * that we are never stopping an array while it is open. 228 * 'reconfig_mutex' protects all other reconfiguration. 229 * These locks are separate due to conflicting interactions 230 * with bdev->bd_mutex. 231 * Lock ordering is: 232 * reconfig_mutex -> bd_mutex : e.g. do_md_run -> revalidate_disk 233 * bd_mutex -> open_mutex: e.g. __blkdev_get -> md_open 234 */ 235 struct mutex open_mutex; 236 struct mutex reconfig_mutex; 237 atomic_t active; /* general refcount */ 238 atomic_t openers; /* number of active opens */ 239 240 int changed; /* true if we might need to reread partition info */ 241 int degraded; /* whether md should consider 242 * adding a spare 243 */ 244 int barriers_work; /* initialised to true, cleared as soon 245 * as a barrier request to slave 246 * fails. Only supported 247 */ 248 struct bio *biolist; /* bios that need to be retried 249 * because BIO_RW_BARRIER is not supported 250 */ 251 252 atomic_t recovery_active; /* blocks scheduled, but not written */ 253 wait_queue_head_t recovery_wait; 254 sector_t recovery_cp; 255 sector_t resync_min; /* user requested sync 256 * starts here */ 257 sector_t resync_max; /* resync should pause 258 * when it gets here */ 259 260 struct sysfs_dirent *sysfs_state; /* handle for 'array_state' 261 * file in sysfs. 262 */ 263 struct sysfs_dirent *sysfs_action; /* handle for 'sync_action' */ 264 265 struct work_struct del_work; /* used for delayed sysfs removal */ 266 267 spinlock_t write_lock; 268 wait_queue_head_t sb_wait; /* for waiting on superblock updates */ 269 atomic_t pending_writes; /* number of active superblock writes */ 270 271 unsigned int safemode; /* if set, update "clean" superblock 272 * when no writes pending. 273 */ 274 unsigned int safemode_delay; 275 struct timer_list safemode_timer; 276 atomic_t writes_pending; 277 struct request_queue *queue; /* for plugging ... */ 278 279 atomic_t write_behind; /* outstanding async IO */ 280 unsigned int max_write_behind; /* 0 = sync */ 281 282 struct bitmap *bitmap; /* the bitmap for the device */ 283 struct file *bitmap_file; /* the bitmap file */ 284 long bitmap_offset; /* offset from superblock of 285 * start of bitmap. May be 286 * negative, but not '0' 287 */ 288 long default_bitmap_offset; /* this is the offset to use when 289 * hot-adding a bitmap. It should 290 * eventually be settable by sysfs. 291 */ 292 293 struct list_head all_mddevs; 294 }; 295 296 297 static inline void rdev_dec_pending(mdk_rdev_t *rdev, mddev_t *mddev) 298 { 299 int faulty = test_bit(Faulty, &rdev->flags); 300 if (atomic_dec_and_test(&rdev->nr_pending) && faulty) 301 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); 302 } 303 304 static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors) 305 { 306 atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io); 307 } 308 309 struct mdk_personality 310 { 311 char *name; 312 int level; 313 struct list_head list; 314 struct module *owner; 315 int (*make_request)(struct request_queue *q, struct bio *bio); 316 int (*run)(mddev_t *mddev); 317 int (*stop)(mddev_t *mddev); 318 void (*status)(struct seq_file *seq, mddev_t *mddev); 319 /* error_handler must set ->faulty and clear ->in_sync 320 * if appropriate, and should abort recovery if needed 321 */ 322 void (*error_handler)(mddev_t *mddev, mdk_rdev_t *rdev); 323 int (*hot_add_disk) (mddev_t *mddev, mdk_rdev_t *rdev); 324 int (*hot_remove_disk) (mddev_t *mddev, int number); 325 int (*spare_active) (mddev_t *mddev); 326 sector_t (*sync_request)(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster); 327 int (*resize) (mddev_t *mddev, sector_t sectors); 328 sector_t (*size) (mddev_t *mddev, sector_t sectors, int raid_disks); 329 int (*check_reshape) (mddev_t *mddev); 330 int (*start_reshape) (mddev_t *mddev); 331 void (*finish_reshape) (mddev_t *mddev); 332 /* quiesce moves between quiescence states 333 * 0 - fully active 334 * 1 - no new requests allowed 335 * others - reserved 336 */ 337 void (*quiesce) (mddev_t *mddev, int state); 338 /* takeover is used to transition an array from one 339 * personality to another. The new personality must be able 340 * to handle the data in the current layout. 341 * e.g. 2drive raid1 -> 2drive raid5 342 * ndrive raid5 -> degraded n+1drive raid6 with special layout 343 * If the takeover succeeds, a new 'private' structure is returned. 344 * This needs to be installed and then ->run used to activate the 345 * array. 346 */ 347 void *(*takeover) (mddev_t *mddev); 348 }; 349 350 351 struct md_sysfs_entry { 352 struct attribute attr; 353 ssize_t (*show)(mddev_t *, char *); 354 ssize_t (*store)(mddev_t *, const char *, size_t); 355 }; 356 357 358 static inline char * mdname (mddev_t * mddev) 359 { 360 return mddev->gendisk ? mddev->gendisk->disk_name : "mdX"; 361 } 362 363 /* 364 * iterates through some rdev ringlist. It's safe to remove the 365 * current 'rdev'. Dont touch 'tmp' though. 366 */ 367 #define rdev_for_each_list(rdev, tmp, head) \ 368 list_for_each_entry_safe(rdev, tmp, head, same_set) 369 370 /* 371 * iterates through the 'same array disks' ringlist 372 */ 373 #define rdev_for_each(rdev, tmp, mddev) \ 374 list_for_each_entry_safe(rdev, tmp, &((mddev)->disks), same_set) 375 376 #define rdev_for_each_rcu(rdev, mddev) \ 377 list_for_each_entry_rcu(rdev, &((mddev)->disks), same_set) 378 379 typedef struct mdk_thread_s { 380 void (*run) (mddev_t *mddev); 381 mddev_t *mddev; 382 wait_queue_head_t wqueue; 383 unsigned long flags; 384 struct task_struct *tsk; 385 unsigned long timeout; 386 } mdk_thread_t; 387 388 #define THREAD_WAKEUP 0 389 390 #define __wait_event_lock_irq(wq, condition, lock, cmd) \ 391 do { \ 392 wait_queue_t __wait; \ 393 init_waitqueue_entry(&__wait, current); \ 394 \ 395 add_wait_queue(&wq, &__wait); \ 396 for (;;) { \ 397 set_current_state(TASK_UNINTERRUPTIBLE); \ 398 if (condition) \ 399 break; \ 400 spin_unlock_irq(&lock); \ 401 cmd; \ 402 schedule(); \ 403 spin_lock_irq(&lock); \ 404 } \ 405 current->state = TASK_RUNNING; \ 406 remove_wait_queue(&wq, &__wait); \ 407 } while (0) 408 409 #define wait_event_lock_irq(wq, condition, lock, cmd) \ 410 do { \ 411 if (condition) \ 412 break; \ 413 __wait_event_lock_irq(wq, condition, lock, cmd); \ 414 } while (0) 415 416 static inline void safe_put_page(struct page *p) 417 { 418 if (p) put_page(p); 419 } 420 421 extern int register_md_personality(struct mdk_personality *p); 422 extern int unregister_md_personality(struct mdk_personality *p); 423 extern mdk_thread_t * md_register_thread(void (*run) (mddev_t *mddev), 424 mddev_t *mddev, const char *name); 425 extern void md_unregister_thread(mdk_thread_t *thread); 426 extern void md_wakeup_thread(mdk_thread_t *thread); 427 extern void md_check_recovery(mddev_t *mddev); 428 extern void md_write_start(mddev_t *mddev, struct bio *bi); 429 extern void md_write_end(mddev_t *mddev); 430 extern void md_done_sync(mddev_t *mddev, int blocks, int ok); 431 extern void md_error(mddev_t *mddev, mdk_rdev_t *rdev); 432 433 extern void md_super_write(mddev_t *mddev, mdk_rdev_t *rdev, 434 sector_t sector, int size, struct page *page); 435 extern void md_super_wait(mddev_t *mddev); 436 extern int sync_page_io(struct block_device *bdev, sector_t sector, int size, 437 struct page *page, int rw); 438 extern void md_do_sync(mddev_t *mddev); 439 extern void md_new_event(mddev_t *mddev); 440 extern int md_allow_write(mddev_t *mddev); 441 extern void md_wait_for_blocked_rdev(mdk_rdev_t *rdev, mddev_t *mddev); 442 extern void md_set_array_sectors(mddev_t *mddev, sector_t array_sectors); 443 extern int md_check_no_bitmap(mddev_t *mddev); 444 extern int md_integrity_register(mddev_t *mddev); 445 void md_integrity_add_rdev(mdk_rdev_t *rdev, mddev_t *mddev); 446 447 #endif /* _MD_MD_H */ 448