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 #ifdef CONFIG_BLOCK
  22
  23 #define LEVEL_MULTIPATH         (-4)
  24 #define LEVEL_LINEAR            (-1)
  25 #define LEVEL_FAULTY            (-5)
  26
  27 /* we need a value for 'no level specified' and 0
  28  * means 'raid0', so we need something else.  This is
  29  * for internal use only
  30  */
  31 #define LEVEL_NONE              (-1000000)
  32
  33 #define MaxSector (~(sector_t)0)
  34
  35 typedef struct mddev_s mddev_t;
  36 typedef struct mdk_rdev_s mdk_rdev_t;
  37
  38 /*
  39  * options passed in raidrun:
  40  */
  41
  42 /* Currently this must fit in an 'int' */
  43 #define MAX_CHUNK_SIZE (1<<30)
  44
  45 /*
  46  * MD's 'extended' device
  47  */
  48 struct mdk_rdev_s
  49 {
  50         struct list_head same_set;      /* RAID devices within the same set */
  51
  52         sector_t size;                  /* Device size (in blocks) */
  53         mddev_t *mddev;                 /* RAID array if running */
  54         long last_events;               /* IO event timestamp */
  55
  56         struct block_device *bdev;      /* block device handle */
  57
  58         struct page     *sb_page;
  59         int             sb_loaded;
  60         __u64           sb_events;
  61         sector_t        data_offset;    /* start of data in array */
  62         sector_t        sb_start;       /* offset of the super block (in 512byte sectors) */
  63         int             sb_size;        /* bytes in the superblock */
  64         int             preferred_minor;        /* autorun support */
  65
  66         struct kobject  kobj;
  67
  68         /* A device can be in one of three states based on two flags:
  69          * Not working:   faulty==1 in_sync==0
  70          * Fully working: faulty==0 in_sync==1
  71          * Working, but not
  72          * in sync with array
  73          *                faulty==0 in_sync==0
  74          *
  75          * It can never have faulty==1, in_sync==1
  76          * This reduces the burden of testing multiple flags in many cases
  77          */
  78
  79         unsigned long   flags;
  80 #define Faulty          1               /* device is known to have a fault */
  81 #define In_sync         2               /* device is in_sync with rest of array */
  82 #define WriteMostly     4               /* Avoid reading if at all possible */
  83 #define BarriersNotsupp 5               /* BIO_RW_BARRIER is not supported */
  84 #define AllReserved     6               /* If whole device is reserved for
  85                                          * one array */
  86 #define AutoDetected    7               /* added by auto-detect */
  87 #define Blocked         8               /* An error occured on an externally
  88                                          * managed array, don't allow writes
  89                                          * until it is cleared */
  90 #define StateChanged    9               /* Faulty or Blocked has changed during
  91                                          * interrupt, so it needs to be
  92                                          * notified by the thread */
  93         wait_queue_head_t blocked_wait;
  94
  95         int desc_nr;                    /* descriptor index in the superblock */
  96         int raid_disk;                  /* role of device in array */
  97         int saved_raid_disk;            /* role that device used to have in the
  98                                          * array and could again if we did a partial
  99                                          * resync from the bitmap
 100                                          */
 101         sector_t        recovery_offset;/* If this device has been partially
 102                                          * recovered, this is where we were
 103                                          * up to.
 104                                          */
 105
 106         atomic_t        nr_pending;     /* number of pending requests.
 107                                          * only maintained for arrays that
 108                                          * support hot removal
 109                                          */
 110         atomic_t        read_errors;    /* number of consecutive read errors that
 111                                          * we have tried to ignore.
 112                                          */
 113         atomic_t        corrected_errors; /* number of corrected read errors,
 114                                            * for reporting to userspace and storing
 115                                            * in superblock.
 116                                            */
 117         struct work_struct del_work;    /* used for delayed sysfs removal */
 118
 119         struct sysfs_dirent *sysfs_state; /* handle for 'state'
 120                                            * sysfs entry */
 121 };
 122
 123 struct mddev_s
 124 {
 125         void                            *private;
 126         struct mdk_personality          *pers;
 127         dev_t                           unit;
 128         int                             md_minor;
 129         struct list_head                disks;
 130         unsigned long                   flags;
 131 #define MD_CHANGE_DEVS  0       /* Some device status has changed */
 132 #define MD_CHANGE_CLEAN 1       /* transition to or from 'clean' */
 133 #define MD_CHANGE_PENDING 2     /* superblock update in progress */
 134
 135         int                             ro;
 136
 137         struct gendisk                  *gendisk;
 138
 139         struct kobject                  kobj;
 140
 141         /* Superblock information */
 142         int                             major_version,
 143                                         minor_version,
 144                                         patch_version;
 145         int                             persistent;
 146         int                             external;       /* metadata is
 147                                                          * managed externally */
 148         char                            metadata_type[17]; /* externally set*/
 149         int                             chunk_size;
 150         time_t                          ctime, utime;
 151         int                             level, layout;
 152         char                            clevel[16];
 153         int                             raid_disks;
 154         int                             max_disks;
 155         sector_t                        size; /* used size of component devices */
 156         sector_t                        array_sectors; /* exported array size */
 157         __u64                           events;
 158
 159         char                            uuid[16];
 160
 161         /* If the array is being reshaped, we need to record the
 162          * new shape and an indication of where we are up to.
 163          * This is written to the superblock.
 164          * If reshape_position is MaxSector, then no reshape is happening (yet).
 165          */
 166         sector_t                        reshape_position;
 167         int                             delta_disks, new_level, new_layout, new_chunk;
 168
 169         struct mdk_thread_s             *thread;        /* management thread */
 170         struct mdk_thread_s             *sync_thread;   /* doing resync or reconstruct */
 171         sector_t                        curr_resync;    /* last block scheduled */
 172         unsigned long                   resync_mark;    /* a recent timestamp */
 173         sector_t                        resync_mark_cnt;/* blocks written at resync_mark */
 174         sector_t                        curr_mark_cnt; /* blocks scheduled now */
 175
 176         sector_t                        resync_max_sectors; /* may be set by personality */
 177
 178         sector_t                        resync_mismatches; /* count of sectors where
 179                                                             * parity/replica mismatch found
 180                                                             */
 181
 182         /* allow user-space to request suspension of IO to regions of the array */
 183         sector_t                        suspend_lo;
 184         sector_t                        suspend_hi;
 185         /* if zero, use the system-wide default */
 186         int                             sync_speed_min;
 187         int                             sync_speed_max;
 188
 189         /* resync even though the same disks are shared among md-devices */
 190         int                             parallel_resync;
 191
 192         int                             ok_start_degraded;
 193         /* recovery/resync flags
 194          * NEEDED:   we might need to start a resync/recover
 195          * RUNNING:  a thread is running, or about to be started
 196          * SYNC:     actually doing a resync, not a recovery
 197          * RECOVER:  doing recovery, or need to try it.
 198          * INTR:     resync needs to be aborted for some reason
 199          * DONE:     thread is done and is waiting to be reaped
 200          * REQUEST:  user-space has requested a sync (used with SYNC)
 201          * CHECK:    user-space request for for check-only, no repair
 202          * RESHAPE:  A reshape is happening
 203          *
 204          * If neither SYNC or RESHAPE are set, then it is a recovery.
 205          */
 206 #define MD_RECOVERY_RUNNING     0
 207 #define MD_RECOVERY_SYNC        1
 208 #define MD_RECOVERY_RECOVER     2
 209 #define MD_RECOVERY_INTR        3
 210 #define MD_RECOVERY_DONE        4
 211 #define MD_RECOVERY_NEEDED      5
 212 #define MD_RECOVERY_REQUESTED   6
 213 #define MD_RECOVERY_CHECK       7
 214 #define MD_RECOVERY_RESHAPE     8
 215 #define MD_RECOVERY_FROZEN      9
 216
 217         unsigned long                   recovery;
 218
 219         int                             in_sync;        /* know to not need resync */
 220         struct mutex                    reconfig_mutex;
 221         atomic_t                        active;         /* general refcount */
 222         atomic_t                        openers;        /* number of active opens */
 223
 224         int                             changed;        /* true if we might need to reread partition info */
 225         int                             degraded;       /* whether md should consider
 226                                                          * adding a spare
 227                                                          */
 228         int                             barriers_work;  /* initialised to true, cleared as soon
 229                                                          * as a barrier request to slave
 230                                                          * fails.  Only supported
 231                                                          */
 232         struct bio                      *biolist;       /* bios that need to be retried
 233                                                          * because BIO_RW_BARRIER is not supported
 234                                                          */
 235
 236         atomic_t                        recovery_active; /* blocks scheduled, but not written */
 237         wait_queue_head_t               recovery_wait;
 238         sector_t                        recovery_cp;
 239         sector_t                        resync_min;     /* user requested sync
 240                                                          * starts here */
 241         sector_t                        resync_max;     /* resync should pause
 242                                                          * when it gets here */
 243
 244         struct sysfs_dirent             *sysfs_state;   /* handle for 'array_state'
 245                                                          * file in sysfs.
 246                                                          */
 247         struct sysfs_dirent             *sysfs_action;  /* handle for 'sync_action' */
 248
 249         spinlock_t                      write_lock;
 250         wait_queue_head_t               sb_wait;        /* for waiting on superblock updates */
 251         atomic_t                        pending_writes; /* number of active superblock writes */
 252
 253         unsigned int                    safemode;       /* if set, update "clean" superblock
 254                                                          * when no writes pending.
 255                                                          */
 256         unsigned int                    safemode_delay;
 257         struct timer_list               safemode_timer;
 258         atomic_t                        writes_pending;
 259         struct request_queue            *queue; /* for plugging ... */
 260
 261         atomic_t                        write_behind; /* outstanding async IO */
 262         unsigned int                    max_write_behind; /* 0 = sync */
 263
 264         struct bitmap                   *bitmap; /* the bitmap for the device */
 265         struct file                     *bitmap_file; /* the bitmap file */
 266         long                            bitmap_offset; /* offset from superblock of
 267                                                         * start of bitmap. May be
 268                                                         * negative, but not '0'
 269                                                         */
 270         long                            default_bitmap_offset; /* this is the offset to use when
 271                                                                 * hot-adding a bitmap.  It should
 272                                                                 * eventually be settable by sysfs.
 273                                                                 */
 274
 275         struct list_head                all_mddevs;
 276 };
 277
 278
 279 static inline void rdev_dec_pending(mdk_rdev_t *rdev, mddev_t *mddev)
 280 {
 281         int faulty = test_bit(Faulty, &rdev->flags);
 282         if (atomic_dec_and_test(&rdev->nr_pending) && faulty)
 283                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
 284 }
 285
 286 static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
 287 {
 288         atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
 289 }
 290
 291 struct mdk_personality
 292 {
 293         char *name;
 294         int level;
 295         struct list_head list;
 296         struct module *owner;
 297         int (*make_request)(struct request_queue *q, struct bio *bio);
 298         int (*run)(mddev_t *mddev);
 299         int (*stop)(mddev_t *mddev);
 300         void (*status)(struct seq_file *seq, mddev_t *mddev);
 301         /* error_handler must set ->faulty and clear ->in_sync
 302          * if appropriate, and should abort recovery if needed
 303          */
 304         void (*error_handler)(mddev_t *mddev, mdk_rdev_t *rdev);
 305         int (*hot_add_disk) (mddev_t *mddev, mdk_rdev_t *rdev);
 306         int (*hot_remove_disk) (mddev_t *mddev, int number);
 307         int (*spare_active) (mddev_t *mddev);
 308         sector_t (*sync_request)(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster);
 309         int (*resize) (mddev_t *mddev, sector_t sectors);
 310         int (*check_reshape) (mddev_t *mddev);
 311         int (*start_reshape) (mddev_t *mddev);
 312         int (*reconfig) (mddev_t *mddev, int layout, int chunk_size);
 313         /* quiesce moves between quiescence states
 314          * 0 - fully active
 315          * 1 - no new requests allowed
 316          * others - reserved
 317          */
 318         void (*quiesce) (mddev_t *mddev, int state);
 319 };
 320
 321
 322 struct md_sysfs_entry {
 323         struct attribute attr;
 324         ssize_t (*show)(mddev_t *, char *);
 325         ssize_t (*store)(mddev_t *, const char *, size_t);
 326 };
 327
 328
 329 static inline char * mdname (mddev_t * mddev)
 330 {
 331         return mddev->gendisk ? mddev->gendisk->disk_name : "mdX";
 332 }
 333
 334 /*
 335  * iterates through some rdev ringlist. It's safe to remove the
 336  * current 'rdev'. Dont touch 'tmp' though.
 337  */
 338 #define rdev_for_each_list(rdev, tmp, list)                             \
 339                                                                         \
 340         for ((tmp) = (list).next;                                       \
 341                 (rdev) = (list_entry((tmp), mdk_rdev_t, same_set)),     \
 342                         (tmp) = (tmp)->next, (tmp)->prev != &(list)     \
 343                 ; )
 344 /*
 345  * iterates through the 'same array disks' ringlist
 346  */
 347 #define rdev_for_each(rdev, tmp, mddev)                         \
 348         rdev_for_each_list(rdev, tmp, (mddev)->disks)
 349
 350 #define rdev_for_each_rcu(rdev, mddev)                          \
 351         list_for_each_entry_rcu(rdev, &((mddev)->disks), same_set)
 352
 353 typedef struct mdk_thread_s {
 354         void                    (*run) (mddev_t *mddev);
 355         mddev_t                 *mddev;
 356         wait_queue_head_t       wqueue;
 357         unsigned long           flags;
 358         struct task_struct      *tsk;
 359         unsigned long           timeout;
 360 } mdk_thread_t;
 361
 362 #define THREAD_WAKEUP  0
 363
 364 #define __wait_event_lock_irq(wq, condition, lock, cmd)                 \
 365 do {                                                                    \
 366         wait_queue_t __wait;                                            \
 367         init_waitqueue_entry(&__wait, current);                         \
 368                                                                         \
 369         add_wait_queue(&wq, &__wait);                                   \
 370         for (;;) {                                                      \
 371                 set_current_state(TASK_UNINTERRUPTIBLE);                \
 372                 if (condition)                                          \
 373                         break;                                          \
 374                 spin_unlock_irq(&lock);                                 \
 375                 cmd;                                                    \
 376                 schedule();                                             \
 377                 spin_lock_irq(&lock);                                   \
 378         }                                                               \
 379         current->state = TASK_RUNNING;                                  \
 380         remove_wait_queue(&wq, &__wait);                                \
 381 } while (0)
 382
 383 #define wait_event_lock_irq(wq, condition, lock, cmd)                   \
 384 do {                                                                    \
 385         if (condition)                                                  \
 386                 break;                                                  \
 387         __wait_event_lock_irq(wq, condition, lock, cmd);                \
 388 } while (0)
 389
 390 static inline void safe_put_page(struct page *p)
 391 {
 392         if (p) put_page(p);
 393 }
 394
 395 #endif /* CONFIG_BLOCK */
 396 #endif
 397