include/linux/raid/md_k.h

   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_K_H
  16 #define _MD_K_H
  17
  18 /* and dm-bio-list.h is not under include/linux because.... ??? */
  19 #include "../../../drivers/md/dm-bio-list.h"
  20
  21 #define MD_RESERVED       0UL
  22 #define LINEAR            1UL
  23 #define RAID0             2UL
  24 #define RAID1             3UL
  25 #define RAID5             4UL
  26 #define TRANSLUCENT       5UL
  27 #define HSM               6UL
  28 #define MULTIPATH         7UL
  29 #define RAID6             8UL
  30 #define RAID10            9UL
  31 #define FAULTY            10UL
  32 #define MAX_PERSONALITY   11UL
  33
  34 #define LEVEL_MULTIPATH         (-4)
  35 #define LEVEL_LINEAR            (-1)
  36 #define LEVEL_FAULTY            (-5)
  37
  38 #define MaxSector (~(sector_t)0)
  39 #define MD_THREAD_NAME_MAX 14
  40
  41 static inline int pers_to_level (int pers)
  42 {
  43         switch (pers) {
  44                 case FAULTY:            return LEVEL_FAULTY;
  45                 case MULTIPATH:         return LEVEL_MULTIPATH;
  46                 case HSM:               return -3;
  47                 case TRANSLUCENT:       return -2;
  48                 case LINEAR:            return LEVEL_LINEAR;
  49                 case RAID0:             return 0;
  50                 case RAID1:             return 1;
  51                 case RAID5:             return 5;
  52                 case RAID6:             return 6;
  53                 case RAID10:            return 10;
  54         }
  55         BUG();
  56         return MD_RESERVED;
  57 }
  58
  59 static inline int level_to_pers (int level)
  60 {
  61         switch (level) {
  62                 case LEVEL_FAULTY: return FAULTY;
  63                 case LEVEL_MULTIPATH: return MULTIPATH;
  64                 case -3: return HSM;
  65                 case -2: return TRANSLUCENT;
  66                 case LEVEL_LINEAR: return LINEAR;
  67                 case 0: return RAID0;
  68                 case 1: return RAID1;
  69                 case 4:
  70                 case 5: return RAID5;
  71                 case 6: return RAID6;
  72                 case 10: return RAID10;
  73         }
  74         return MD_RESERVED;
  75 }
  76
  77 typedef struct mddev_s mddev_t;
  78 typedef struct mdk_rdev_s mdk_rdev_t;
  79
  80 #define MAX_MD_DEVS  256        /* Max number of md dev */
  81
  82 /*
  83  * options passed in raidrun:
  84  */
  85
  86 #define MAX_CHUNK_SIZE (4096*1024)
  87
  88 /*
  89  * MD's 'extended' device
  90  */
  91 struct mdk_rdev_s
  92 {
  93         struct list_head same_set;      /* RAID devices within the same set */
  94
  95         sector_t size;                  /* Device size (in blocks) */
  96         mddev_t *mddev;                 /* RAID array if running */
  97         unsigned long last_events;      /* IO event timestamp */
  98
  99         struct block_device *bdev;      /* block device handle */
 100
 101         struct page     *sb_page;
 102         int             sb_loaded;
 103         sector_t        data_offset;    /* start of data in array */
 104         sector_t        sb_offset;
 105         int             sb_size;        /* bytes in the superblock */
 106         int             preferred_minor;        /* autorun support */
 107
 108         struct kobject  kobj;
 109
 110         /* A device can be in one of three states based on two flags:
 111          * Not working:   faulty==1 in_sync==0
 112          * Fully working: faulty==0 in_sync==1
 113          * Working, but not
 114          * in sync with array
 115          *                faulty==0 in_sync==0
 116          *
 117          * It can never have faulty==1, in_sync==1
 118          * This reduces the burden of testing multiple flags in many cases
 119          */
 120
 121         unsigned long   flags;
 122 #define Faulty          1               /* device is known to have a fault */
 123 #define In_sync         2               /* device is in_sync with rest of array */
 124 #define WriteMostly     4               /* Avoid reading if at all possible */
 125 #define BarriersNotsupp 5               /* BIO_RW_BARRIER is not supported */
 126
 127         int desc_nr;                    /* descriptor index in the superblock */
 128         int raid_disk;                  /* role of device in array */
 129         int saved_raid_disk;            /* role that device used to have in the
 130                                          * array and could again if we did a partial
 131                                          * resync from the bitmap
 132                                          */
 133
 134         atomic_t        nr_pending;     /* number of pending requests.
 135                                          * only maintained for arrays that
 136                                          * support hot removal
 137                                          */
 138         atomic_t        read_errors;    /* number of consecutive read errors that
 139                                          * we have tried to ignore.
 140                                          */
 141 };
 142
 143 typedef struct mdk_personality_s mdk_personality_t;
 144
 145 struct mddev_s
 146 {
 147         void                            *private;
 148         mdk_personality_t               *pers;
 149         dev_t                           unit;
 150         int                             md_minor;
 151         struct list_head                disks;
 152         int                             sb_dirty;
 153         int                             ro;
 154
 155         struct gendisk                  *gendisk;
 156
 157         struct kobject                  kobj;
 158
 159         /* Superblock information */
 160         int                             major_version,
 161                                         minor_version,
 162                                         patch_version;
 163         int                             persistent;
 164         int                             chunk_size;
 165         time_t                          ctime, utime;
 166         int                             level, layout;
 167         int                             raid_disks;
 168         int                             max_disks;
 169         sector_t                        size; /* used size of component devices */
 170         sector_t                        array_size; /* exported array size */
 171         __u64                           events;
 172
 173         char                            uuid[16];
 174
 175         struct mdk_thread_s             *thread;        /* management thread */
 176         struct mdk_thread_s             *sync_thread;   /* doing resync or reconstruct */
 177         sector_t                        curr_resync;    /* blocks scheduled */
 178         unsigned long                   resync_mark;    /* a recent timestamp */
 179         sector_t                        resync_mark_cnt;/* blocks written at resync_mark */
 180
 181         sector_t                        resync_max_sectors; /* may be set by personality */
 182
 183         sector_t                        resync_mismatches; /* count of sectors where
 184                                                             * parity/replica mismatch found
 185                                                             */
 186         /* recovery/resync flags
 187          * NEEDED:   we might need to start a resync/recover
 188          * RUNNING:  a thread is running, or about to be started
 189          * SYNC:     actually doing a resync, not a recovery
 190          * ERR:      and IO error was detected - abort the resync/recovery
 191          * INTR:     someone requested a (clean) early abort.
 192          * DONE:     thread is done and is waiting to be reaped
 193          * REQUEST:  user-space has requested a sync (used with SYNC)
 194          * CHECK:    user-space request for for check-only, no repair
 195          */
 196 #define MD_RECOVERY_RUNNING     0
 197 #define MD_RECOVERY_SYNC        1
 198 #define MD_RECOVERY_ERR         2
 199 #define MD_RECOVERY_INTR        3
 200 #define MD_RECOVERY_DONE        4
 201 #define MD_RECOVERY_NEEDED      5
 202 #define MD_RECOVERY_REQUESTED   6
 203 #define MD_RECOVERY_CHECK       7
 204         unsigned long                   recovery;
 205
 206         int                             in_sync;        /* know to not need resync */
 207         struct semaphore                reconfig_sem;
 208         atomic_t                        active;
 209
 210         int                             changed;        /* true if we might need to reread partition info */
 211         int                             degraded;       /* whether md should consider
 212                                                          * adding a spare
 213                                                          */
 214         int                             barriers_work;  /* initialised to true, cleared as soon
 215                                                          * as a barrier request to slave
 216                                                          * fails.  Only supported
 217                                                          */
 218         struct bio                      *biolist;       /* bios that need to be retried
 219                                                          * because BIO_RW_BARRIER is not supported
 220                                                          */
 221
 222         atomic_t                        recovery_active; /* blocks scheduled, but not written */
 223         wait_queue_head_t               recovery_wait;
 224         sector_t                        recovery_cp;
 225
 226         spinlock_t                      write_lock;
 227         wait_queue_head_t               sb_wait;        /* for waiting on superblock updates */
 228         atomic_t                        pending_writes; /* number of active superblock writes */
 229
 230         unsigned int                    safemode;       /* if set, update "clean" superblock
 231                                                          * when no writes pending.
 232                                                          */
 233         unsigned int                    safemode_delay;
 234         struct timer_list               safemode_timer;
 235         atomic_t                        writes_pending;
 236         request_queue_t                 *queue; /* for plugging ... */
 237
 238         atomic_t                        write_behind; /* outstanding async IO */
 239         unsigned int                    max_write_behind; /* 0 = sync */
 240
 241         struct bitmap                   *bitmap; /* the bitmap for the device */
 242         struct file                     *bitmap_file; /* the bitmap file */
 243         long                            bitmap_offset; /* offset from superblock of
 244                                                         * start of bitmap. May be
 245                                                         * negative, but not '0'
 246                                                         */
 247         long                            default_bitmap_offset; /* this is the offset to use when
 248                                                                 * hot-adding a bitmap.  It should
 249                                                                 * eventually be settable by sysfs.
 250                                                                 */
 251
 252         struct list_head                all_mddevs;
 253 };
 254
 255
 256 static inline void rdev_dec_pending(mdk_rdev_t *rdev, mddev_t *mddev)
 257 {
 258         int faulty = test_bit(Faulty, &rdev->flags);
 259         if (atomic_dec_and_test(&rdev->nr_pending) && faulty)
 260                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
 261 }
 262
 263 static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
 264 {
 265         atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
 266 }
 267
 268 struct mdk_personality_s
 269 {
 270         char *name;
 271         struct module *owner;
 272         int (*make_request)(request_queue_t *q, struct bio *bio);
 273         int (*run)(mddev_t *mddev);
 274         int (*stop)(mddev_t *mddev);
 275         void (*status)(struct seq_file *seq, mddev_t *mddev);
 276         /* error_handler must set ->faulty and clear ->in_sync
 277          * if appropriate, and should abort recovery if needed
 278          */
 279         void (*error_handler)(mddev_t *mddev, mdk_rdev_t *rdev);
 280         int (*hot_add_disk) (mddev_t *mddev, mdk_rdev_t *rdev);
 281         int (*hot_remove_disk) (mddev_t *mddev, int number);
 282         int (*spare_active) (mddev_t *mddev);
 283         sector_t (*sync_request)(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster);
 284         int (*resize) (mddev_t *mddev, sector_t sectors);
 285         int (*reshape) (mddev_t *mddev, int raid_disks);
 286         int (*reconfig) (mddev_t *mddev, int layout, int chunk_size);
 287         /* quiesce moves between quiescence states
 288          * 0 - fully active
 289          * 1 - no new requests allowed
 290          * others - reserved
 291          */
 292         void (*quiesce) (mddev_t *mddev, int state);
 293 };
 294
 295
 296 struct md_sysfs_entry {
 297         struct attribute attr;
 298         ssize_t (*show)(mddev_t *, char *);
 299         ssize_t (*store)(mddev_t *, const char *, size_t);
 300 };
 301
 302
 303 static inline char * mdname (mddev_t * mddev)
 304 {
 305         return mddev->gendisk ? mddev->gendisk->disk_name : "mdX";
 306 }
 307
 308 extern mdk_rdev_t * find_rdev_nr(mddev_t *mddev, int nr);
 309
 310 /*
 311  * iterates through some rdev ringlist. It's safe to remove the
 312  * current 'rdev'. Dont touch 'tmp' though.
 313  */
 314 #define ITERATE_RDEV_GENERIC(head,rdev,tmp)                             \
 315                                                                         \
 316         for ((tmp) = (head).next;                                       \
 317                 (rdev) = (list_entry((tmp), mdk_rdev_t, same_set)),     \
 318                         (tmp) = (tmp)->next, (tmp)->prev != &(head)     \
 319                 ; )
 320 /*
 321  * iterates through the 'same array disks' ringlist
 322  */
 323 #define ITERATE_RDEV(mddev,rdev,tmp)                                    \
 324         ITERATE_RDEV_GENERIC((mddev)->disks,rdev,tmp)
 325
 326 /*
 327  * Iterates through 'pending RAID disks'
 328  */
 329 #define ITERATE_RDEV_PENDING(rdev,tmp)                                  \
 330         ITERATE_RDEV_GENERIC(pending_raid_disks,rdev,tmp)
 331
 332 typedef struct mdk_thread_s {
 333         void                    (*run) (mddev_t *mddev);
 334         mddev_t                 *mddev;
 335         wait_queue_head_t       wqueue;
 336         unsigned long           flags;
 337         struct task_struct      *tsk;
 338         unsigned long           timeout;
 339 } mdk_thread_t;
 340
 341 #define THREAD_WAKEUP  0
 342
 343 #define __wait_event_lock_irq(wq, condition, lock, cmd)                 \
 344 do {                                                                    \
 345         wait_queue_t __wait;                                            \
 346         init_waitqueue_entry(&__wait, current);                         \
 347                                                                         \
 348         add_wait_queue(&wq, &__wait);                                   \
 349         for (;;) {                                                      \
 350                 set_current_state(TASK_UNINTERRUPTIBLE);                \
 351                 if (condition)                                          \
 352                         break;                                          \
 353                 spin_unlock_irq(&lock);                                 \
 354                 cmd;                                                    \
 355                 schedule();                                             \
 356                 spin_lock_irq(&lock);                                   \
 357         }                                                               \
 358         current->state = TASK_RUNNING;                                  \
 359         remove_wait_queue(&wq, &__wait);                                \
 360 } while (0)
 361
 362 #define wait_event_lock_irq(wq, condition, lock, cmd)                   \
 363 do {                                                                    \
 364         if (condition)                                                  \
 365                 break;                                                  \
 366         __wait_event_lock_irq(wq, condition, lock, cmd);                \
 367 } while (0)
 368
 369 #endif
 370