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 * options passed in raidrun: 34 */ 35 36 /* Currently this must fit in an 'int' */ 37 #define MAX_CHUNK_SIZE (1<<30) 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 struct block_device *bdev; /* block device handle */ 51 52 struct page *sb_page; 53 int sb_loaded; 54 __u64 sb_events; 55 sector_t data_offset; /* start of data in array */ 56 sector_t sb_start; /* offset of the super block (in 512byte sectors) */ 57 int sb_size; /* bytes in the superblock */ 58 int preferred_minor; /* autorun support */ 59 60 struct kobject kobj; 61 62 /* A device can be in one of three states based on two flags: 63 * Not working: faulty==1 in_sync==0 64 * Fully working: faulty==0 in_sync==1 65 * Working, but not 66 * in sync with array 67 * faulty==0 in_sync==0 68 * 69 * It can never have faulty==1, in_sync==1 70 * This reduces the burden of testing multiple flags in many cases 71 */ 72 73 unsigned long flags; 74 #define Faulty 1 /* device is known to have a fault */ 75 #define In_sync 2 /* device is in_sync with rest of array */ 76 #define WriteMostly 4 /* Avoid reading if at all possible */ 77 #define BarriersNotsupp 5 /* BIO_RW_BARRIER is not supported */ 78 #define AllReserved 6 /* If whole device is reserved for 79 * one array */ 80 #define AutoDetected 7 /* added by auto-detect */ 81 #define Blocked 8 /* An error occured on an externally 82 * managed array, don't allow writes 83 * until it is cleared */ 84 #define StateChanged 9 /* Faulty or Blocked has changed during 85 * interrupt, so it needs to be 86 * notified by the thread */ 87 wait_queue_head_t blocked_wait; 88 89 int desc_nr; /* descriptor index in the superblock */ 90 int raid_disk; /* role of device in array */ 91 int saved_raid_disk; /* role that device used to have in the 92 * array and could again if we did a partial 93 * resync from the bitmap 94 */ 95 sector_t recovery_offset;/* If this device has been partially 96 * recovered, this is where we were 97 * up to. 98 */ 99 100 atomic_t nr_pending; /* number of pending requests. 101 * only maintained for arrays that 102 * support hot removal 103 */ 104 atomic_t read_errors; /* number of consecutive read errors that 105 * we have tried to ignore. 106 */ 107 atomic_t corrected_errors; /* number of corrected read errors, 108 * for reporting to userspace and storing 109 * in superblock. 110 */ 111 struct work_struct del_work; /* used for delayed sysfs removal */ 112 113 struct sysfs_dirent *sysfs_state; /* handle for 'state' 114 * sysfs entry */ 115 }; 116 117 struct mddev_s 118 { 119 void *private; 120 struct mdk_personality *pers; 121 dev_t unit; 122 int md_minor; 123 struct list_head disks; 124 unsigned long flags; 125 #define MD_CHANGE_DEVS 0 /* Some device status has changed */ 126 #define MD_CHANGE_CLEAN 1 /* transition to or from 'clean' */ 127 #define MD_CHANGE_PENDING 2 /* superblock update in progress */ 128 129 int suspended; 130 atomic_t active_io; 131 int ro; 132 133 struct gendisk *gendisk; 134 135 struct kobject kobj; 136 int hold_active; 137 #define UNTIL_IOCTL 1 138 #define UNTIL_STOP 2 139 140 /* Superblock information */ 141 int major_version, 142 minor_version, 143 patch_version; 144 int persistent; 145 int external; /* metadata is 146 * managed externally */ 147 char metadata_type[17]; /* externally set*/ 148 int chunk_size; 149 time_t ctime, utime; 150 int level, layout; 151 char clevel[16]; 152 int raid_disks; 153 int max_disks; 154 sector_t dev_sectors; /* used size of 155 * component devices */ 156 sector_t array_sectors; /* exported array size */ 157 int external_size; /* size managed 158 * externally */ 159 __u64 events; 160 161 char uuid[16]; 162 163 /* If the array is being reshaped, we need to record the 164 * new shape and an indication of where we are up to. 165 * This is written to the superblock. 166 * If reshape_position is MaxSector, then no reshape is happening (yet). 167 */ 168 sector_t reshape_position; 169 int delta_disks, new_level, new_layout, new_chunk; 170 171 struct mdk_thread_s *thread; /* management thread */ 172 struct mdk_thread_s *sync_thread; /* doing resync or reconstruct */ 173 sector_t curr_resync; /* last block scheduled */ 174 /* As resync requests can complete out of order, we cannot easily track 175 * how much resync has been completed. So we occasionally pause until 176 * everything completes, then set curr_resync_completed to curr_resync. 177 * As such it may be well behind the real resync mark, but it is a value 178 * we are certain of. 179 */ 180 sector_t curr_resync_completed; 181 unsigned long resync_mark; /* a recent timestamp */ 182 sector_t resync_mark_cnt;/* blocks written at resync_mark */ 183 sector_t curr_mark_cnt; /* blocks scheduled now */ 184 185 sector_t resync_max_sectors; /* may be set by personality */ 186 187 sector_t resync_mismatches; /* count of sectors where 188 * parity/replica mismatch found 189 */ 190 191 /* allow user-space to request suspension of IO to regions of the array */ 192 sector_t suspend_lo; 193 sector_t suspend_hi; 194 /* if zero, use the system-wide default */ 195 int sync_speed_min; 196 int sync_speed_max; 197 198 /* resync even though the same disks are shared among md-devices */ 199 int parallel_resync; 200 201 int ok_start_degraded; 202 /* recovery/resync flags 203 * NEEDED: we might need to start a resync/recover 204 * RUNNING: a thread is running, or about to be started 205 * SYNC: actually doing a resync, not a recovery 206 * RECOVER: doing recovery, or need to try it. 207 * INTR: resync needs to be aborted for some reason 208 * DONE: thread is done and is waiting to be reaped 209 * REQUEST: user-space has requested a sync (used with SYNC) 210 * CHECK: user-space request for for check-only, no repair 211 * RESHAPE: A reshape is happening 212 * 213 * If neither SYNC or RESHAPE are set, then it is a recovery. 214 */ 215 #define MD_RECOVERY_RUNNING 0 216 #define MD_RECOVERY_SYNC 1 217 #define MD_RECOVERY_RECOVER 2 218 #define MD_RECOVERY_INTR 3 219 #define MD_RECOVERY_DONE 4 220 #define MD_RECOVERY_NEEDED 5 221 #define MD_RECOVERY_REQUESTED 6 222 #define MD_RECOVERY_CHECK 7 223 #define MD_RECOVERY_RESHAPE 8 224 #define MD_RECOVERY_FROZEN 9 225 226 unsigned long recovery; 227 int recovery_disabled; /* if we detect that recovery 228 * will always fail, set this 229 * so we don't loop trying */ 230 231 int in_sync; /* know to not need resync */ 232 struct mutex reconfig_mutex; 233 atomic_t active; /* general refcount */ 234 atomic_t openers; /* number of active opens */ 235 236 int changed; /* true if we might need to reread partition info */ 237 int degraded; /* whether md should consider 238 * adding a spare 239 */ 240 int barriers_work; /* initialised to true, cleared as soon 241 * as a barrier request to slave 242 * fails. Only supported 243 */ 244 struct bio *biolist; /* bios that need to be retried 245 * because BIO_RW_BARRIER is not supported 246 */ 247 248 atomic_t recovery_active; /* blocks scheduled, but not written */ 249 wait_queue_head_t recovery_wait; 250 sector_t recovery_cp; 251 sector_t resync_min; /* user requested sync 252 * starts here */ 253 sector_t resync_max; /* resync should pause 254 * when it gets here */ 255 256 struct sysfs_dirent *sysfs_state; /* handle for 'array_state' 257 * file in sysfs. 258 */ 259 struct sysfs_dirent *sysfs_action; /* handle for 'sync_action' */ 260 261 struct work_struct del_work; /* used for delayed sysfs removal */ 262 263 spinlock_t write_lock; 264 wait_queue_head_t sb_wait; /* for waiting on superblock updates */ 265 atomic_t pending_writes; /* number of active superblock writes */ 266 267 unsigned int safemode; /* if set, update "clean" superblock 268 * when no writes pending. 269 */ 270 unsigned int safemode_delay; 271 struct timer_list safemode_timer; 272 atomic_t writes_pending; 273 struct request_queue *queue; /* for plugging ... */ 274 275 atomic_t write_behind; /* outstanding async IO */ 276 unsigned int max_write_behind; /* 0 = sync */ 277 278 struct bitmap *bitmap; /* the bitmap for the device */ 279 struct file *bitmap_file; /* the bitmap file */ 280 long bitmap_offset; /* offset from superblock of 281 * start of bitmap. May be 282 * negative, but not '0' 283 */ 284 long default_bitmap_offset; /* this is the offset to use when 285 * hot-adding a bitmap. It should 286 * eventually be settable by sysfs. 287 */ 288 289 struct list_head all_mddevs; 290 }; 291 292 293 static inline void rdev_dec_pending(mdk_rdev_t *rdev, mddev_t *mddev) 294 { 295 int faulty = test_bit(Faulty, &rdev->flags); 296 if (atomic_dec_and_test(&rdev->nr_pending) && faulty) 297 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); 298 } 299 300 static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors) 301 { 302 atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io); 303 } 304 305 struct mdk_personality 306 { 307 char *name; 308 int level; 309 struct list_head list; 310 struct module *owner; 311 int (*make_request)(struct request_queue *q, struct bio *bio); 312 int (*run)(mddev_t *mddev); 313 int (*stop)(mddev_t *mddev); 314 void (*status)(struct seq_file *seq, mddev_t *mddev); 315 /* error_handler must set ->faulty and clear ->in_sync 316 * if appropriate, and should abort recovery if needed 317 */ 318 void (*error_handler)(mddev_t *mddev, mdk_rdev_t *rdev); 319 int (*hot_add_disk) (mddev_t *mddev, mdk_rdev_t *rdev); 320 int (*hot_remove_disk) (mddev_t *mddev, int number); 321 int (*spare_active) (mddev_t *mddev); 322 sector_t (*sync_request)(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster); 323 int (*resize) (mddev_t *mddev, sector_t sectors); 324 sector_t (*size) (mddev_t *mddev, sector_t sectors, int raid_disks); 325 int (*check_reshape) (mddev_t *mddev); 326 int (*start_reshape) (mddev_t *mddev); 327 void (*finish_reshape) (mddev_t *mddev); 328 int (*reconfig) (mddev_t *mddev, int layout, int chunk_size); 329 /* quiesce moves between quiescence states 330 * 0 - fully active 331 * 1 - no new requests allowed 332 * others - reserved 333 */ 334 void (*quiesce) (mddev_t *mddev, int state); 335 /* takeover is used to transition an array from one 336 * personality to another. The new personality must be able 337 * to handle the data in the current layout. 338 * e.g. 2drive raid1 -> 2drive raid5 339 * ndrive raid5 -> degraded n+1drive raid6 with special layout 340 * If the takeover succeeds, a new 'private' structure is returned. 341 * This needs to be installed and then ->run used to activate the 342 * array. 343 */ 344 void *(*takeover) (mddev_t *mddev); 345 }; 346 347 348 struct md_sysfs_entry { 349 struct attribute attr; 350 ssize_t (*show)(mddev_t *, char *); 351 ssize_t (*store)(mddev_t *, const char *, size_t); 352 }; 353 354 355 static inline char * mdname (mddev_t * mddev) 356 { 357 return mddev->gendisk ? mddev->gendisk->disk_name : "mdX"; 358 } 359 360 /* 361 * iterates through some rdev ringlist. It's safe to remove the 362 * current 'rdev'. Dont touch 'tmp' though. 363 */ 364 #define rdev_for_each_list(rdev, tmp, head) \ 365 list_for_each_entry_safe(rdev, tmp, head, same_set) 366 367 /* 368 * iterates through the 'same array disks' ringlist 369 */ 370 #define rdev_for_each(rdev, tmp, mddev) \ 371 list_for_each_entry_safe(rdev, tmp, &((mddev)->disks), same_set) 372 373 #define rdev_for_each_rcu(rdev, mddev) \ 374 list_for_each_entry_rcu(rdev, &((mddev)->disks), same_set) 375 376 typedef struct mdk_thread_s { 377 void (*run) (mddev_t *mddev); 378 mddev_t *mddev; 379 wait_queue_head_t wqueue; 380 unsigned long flags; 381 struct task_struct *tsk; 382 unsigned long timeout; 383 } mdk_thread_t; 384 385 #define THREAD_WAKEUP 0 386 387 #define __wait_event_lock_irq(wq, condition, lock, cmd) \ 388 do { \ 389 wait_queue_t __wait; \ 390 init_waitqueue_entry(&__wait, current); \ 391 \ 392 add_wait_queue(&wq, &__wait); \ 393 for (;;) { \ 394 set_current_state(TASK_UNINTERRUPTIBLE); \ 395 if (condition) \ 396 break; \ 397 spin_unlock_irq(&lock); \ 398 cmd; \ 399 schedule(); \ 400 spin_lock_irq(&lock); \ 401 } \ 402 current->state = TASK_RUNNING; \ 403 remove_wait_queue(&wq, &__wait); \ 404 } while (0) 405 406 #define wait_event_lock_irq(wq, condition, lock, cmd) \ 407 do { \ 408 if (condition) \ 409 break; \ 410 __wait_event_lock_irq(wq, condition, lock, cmd); \ 411 } while (0) 412 413 static inline void safe_put_page(struct page *p) 414 { 415 if (p) put_page(p); 416 } 417 418 extern int register_md_personality(struct mdk_personality *p); 419 extern int unregister_md_personality(struct mdk_personality *p); 420 extern mdk_thread_t * md_register_thread(void (*run) (mddev_t *mddev), 421 mddev_t *mddev, const char *name); 422 extern void md_unregister_thread(mdk_thread_t *thread); 423 extern void md_wakeup_thread(mdk_thread_t *thread); 424 extern void md_check_recovery(mddev_t *mddev); 425 extern void md_write_start(mddev_t *mddev, struct bio *bi); 426 extern void md_write_end(mddev_t *mddev); 427 extern void md_done_sync(mddev_t *mddev, int blocks, int ok); 428 extern void md_error(mddev_t *mddev, mdk_rdev_t *rdev); 429 430 extern void md_super_write(mddev_t *mddev, mdk_rdev_t *rdev, 431 sector_t sector, int size, struct page *page); 432 extern void md_super_wait(mddev_t *mddev); 433 extern int sync_page_io(struct block_device *bdev, sector_t sector, int size, 434 struct page *page, int rw); 435 extern void md_do_sync(mddev_t *mddev); 436 extern void md_new_event(mddev_t *mddev); 437 extern int md_allow_write(mddev_t *mddev); 438 extern void md_wait_for_blocked_rdev(mdk_rdev_t *rdev, mddev_t *mddev); 439 extern void md_set_array_sectors(mddev_t *mddev, sector_t array_sectors); 440 441 #endif /* _MD_MD_H */ 442