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
 120 struct mddev_s
 121 {
 122         void                            *private;
 123         struct mdk_personality          *pers;
 124         dev_t                           unit;
 125         int                             md_minor;
 126         struct list_head                disks;
 127         unsigned long                   flags;
 128 #define MD_CHANGE_DEVS  0       /* Some device status has changed */
 129 #define MD_CHANGE_CLEAN 1       /* transition to or from 'clean' */
 130 #define MD_CHANGE_PENDING 2     /* superblock update in progress */
 131 #define MD_NOTIFY_ARRAY_STATE 3 /* atomic context wants to notify userspace */
 132
 133         int                             ro;
 134
 135         struct gendisk                  *gendisk;
 136
 137         struct kobject                  kobj;
 138
 139         /* Superblock information */
 140         int                             major_version,
 141                                         minor_version,
 142                                         patch_version;
 143         int                             persistent;
 144         int                             external;       /* metadata is
 145                                                          * managed externally */
 146         char                            metadata_type[17]; /* externally set*/
 147         int                             chunk_size;
 148         time_t                          ctime, utime;
 149         int                             level, layout;
 150         char                            clevel[16];
 151         int                             raid_disks;
 152         int                             max_disks;
 153         sector_t                        size; /* used size of component devices */
 154         sector_t                        array_sectors; /* exported array size */
 155         __u64                           events;
 156
 157         char                            uuid[16];
 158
 159         /* If the array is being reshaped, we need to record the
 160          * new shape and an indication of where we are up to.
 161          * This is written to the superblock.
 162          * If reshape_position is MaxSector, then no reshape is happening (yet).
 163          */
 164         sector_t                        reshape_position;
 165         int                             delta_disks, new_level, new_layout, new_chunk;
 166
 167         struct mdk_thread_s             *thread;        /* management thread */
 168         struct mdk_thread_s             *sync_thread;   /* doing resync or reconstruct */
 169         sector_t                        curr_resync;    /* last block scheduled */
 170         unsigned long                   resync_mark;    /* a recent timestamp */
 171         sector_t                        resync_mark_cnt;/* blocks written at resync_mark */
 172         sector_t                        curr_mark_cnt; /* blocks scheduled now */
 173
 174         sector_t                        resync_max_sectors; /* may be set by personality */
 175
 176         sector_t                        resync_mismatches; /* count of sectors where
 177                                                             * parity/replica mismatch found
 178                                                             */
 179
 180         /* allow user-space to request suspension of IO to regions of the array */
 181         sector_t                        suspend_lo;
 182         sector_t                        suspend_hi;
 183         /* if zero, use the system-wide default */
 184         int                             sync_speed_min;
 185         int                             sync_speed_max;
 186
 187         /* resync even though the same disks are shared among md-devices */
 188         int                             parallel_resync;
 189
 190         int                             ok_start_degraded;
 191         /* recovery/resync flags
 192          * NEEDED:   we might need to start a resync/recover
 193          * RUNNING:  a thread is running, or about to be started
 194          * SYNC:     actually doing a resync, not a recovery
 195          * RECOVER:  doing recovery, or need to try it.
 196          * INTR:     resync needs to be aborted for some reason
 197          * DONE:     thread is done and is waiting to be reaped
 198          * REQUEST:  user-space has requested a sync (used with SYNC)
 199          * CHECK:    user-space request for for check-only, no repair
 200          * RESHAPE:  A reshape is happening
 201          *
 202          * If neither SYNC or RESHAPE are set, then it is a recovery.
 203          */
 204 #define MD_RECOVERY_RUNNING     0
 205 #define MD_RECOVERY_SYNC        1
 206 #define MD_RECOVERY_RECOVER     2
 207 #define MD_RECOVERY_INTR        3
 208 #define MD_RECOVERY_DONE        4
 209 #define MD_RECOVERY_NEEDED      5
 210 #define MD_RECOVERY_REQUESTED   6
 211 #define MD_RECOVERY_CHECK       7
 212 #define MD_RECOVERY_RESHAPE     8
 213 #define MD_RECOVERY_FROZEN      9
 214
 215         unsigned long                   recovery;
 216
 217         int                             in_sync;        /* know to not need resync */
 218         struct mutex                    reconfig_mutex;
 219         atomic_t                        active;         /* general refcount */
 220         atomic_t                        openers;        /* number of active opens */
 221
 222         int                             changed;        /* true if we might need to reread partition info */
 223         int                             degraded;       /* whether md should consider
 224                                                          * adding a spare
 225                                                          */
 226         int                             barriers_work;  /* initialised to true, cleared as soon
 227                                                          * as a barrier request to slave
 228                                                          * fails.  Only supported
 229                                                          */
 230         struct bio                      *biolist;       /* bios that need to be retried
 231                                                          * because BIO_RW_BARRIER is not supported
 232                                                          */
 233
 234         atomic_t                        recovery_active; /* blocks scheduled, but not written */
 235         wait_queue_head_t               recovery_wait;
 236         sector_t                        recovery_cp;
 237         sector_t                        resync_min;     /* user requested sync
 238                                                          * starts here */
 239         sector_t                        resync_max;     /* resync should pause
 240                                                          * when it gets here */
 241
 242         spinlock_t                      write_lock;
 243         wait_queue_head_t               sb_wait;        /* for waiting on superblock updates */
 244         atomic_t                        pending_writes; /* number of active superblock writes */
 245
 246         unsigned int                    safemode;       /* if set, update "clean" superblock
 247                                                          * when no writes pending.
 248                                                          */
 249         unsigned int                    safemode_delay;
 250         struct timer_list               safemode_timer;
 251         atomic_t                        writes_pending;
 252         struct request_queue            *queue; /* for plugging ... */
 253
 254         atomic_t                        write_behind; /* outstanding async IO */
 255         unsigned int                    max_write_behind; /* 0 = sync */
 256
 257         struct bitmap                   *bitmap; /* the bitmap for the device */
 258         struct file                     *bitmap_file; /* the bitmap file */
 259         long                            bitmap_offset; /* offset from superblock of
 260                                                         * start of bitmap. May be
 261                                                         * negative, but not '0'
 262                                                         */
 263         long                            default_bitmap_offset; /* this is the offset to use when
 264                                                                 * hot-adding a bitmap.  It should
 265                                                                 * eventually be settable by sysfs.
 266                                                                 */
 267
 268         struct list_head                all_mddevs;
 269 };
 270
 271
 272 static inline void rdev_dec_pending(mdk_rdev_t *rdev, mddev_t *mddev)
 273 {
 274         int faulty = test_bit(Faulty, &rdev->flags);
 275         if (atomic_dec_and_test(&rdev->nr_pending) && faulty)
 276                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
 277 }
 278
 279 static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
 280 {
 281         atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
 282 }
 283
 284 struct mdk_personality
 285 {
 286         char *name;
 287         int level;
 288         struct list_head list;
 289         struct module *owner;
 290         int (*make_request)(struct request_queue *q, struct bio *bio);
 291         int (*run)(mddev_t *mddev);
 292         int (*stop)(mddev_t *mddev);
 293         void (*status)(struct seq_file *seq, mddev_t *mddev);
 294         /* error_handler must set ->faulty and clear ->in_sync
 295          * if appropriate, and should abort recovery if needed
 296          */
 297         void (*error_handler)(mddev_t *mddev, mdk_rdev_t *rdev);
 298         int (*hot_add_disk) (mddev_t *mddev, mdk_rdev_t *rdev);
 299         int (*hot_remove_disk) (mddev_t *mddev, int number);
 300         int (*spare_active) (mddev_t *mddev);
 301         sector_t (*sync_request)(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster);
 302         int (*resize) (mddev_t *mddev, sector_t sectors);
 303         int (*check_reshape) (mddev_t *mddev);
 304         int (*start_reshape) (mddev_t *mddev);
 305         int (*reconfig) (mddev_t *mddev, int layout, int chunk_size);
 306         /* quiesce moves between quiescence states
 307          * 0 - fully active
 308          * 1 - no new requests allowed
 309          * others - reserved
 310          */
 311         void (*quiesce) (mddev_t *mddev, int state);
 312 };
 313
 314
 315 struct md_sysfs_entry {
 316         struct attribute attr;
 317         ssize_t (*show)(mddev_t *, char *);
 318         ssize_t (*store)(mddev_t *, const char *, size_t);
 319 };
 320
 321
 322 static inline char * mdname (mddev_t * mddev)
 323 {
 324         return mddev->gendisk ? mddev->gendisk->disk_name : "mdX";
 325 }
 326
 327 /*
 328  * iterates through some rdev ringlist. It's safe to remove the
 329  * current 'rdev'. Dont touch 'tmp' though.
 330  */
 331 #define rdev_for_each_list(rdev, tmp, list)                             \
 332                                                                         \
 333         for ((tmp) = (list).next;                                       \
 334                 (rdev) = (list_entry((tmp), mdk_rdev_t, same_set)),     \
 335                         (tmp) = (tmp)->next, (tmp)->prev != &(list)     \
 336                 ; )
 337 /*
 338  * iterates through the 'same array disks' ringlist
 339  */
 340 #define rdev_for_each(rdev, tmp, mddev)                         \
 341         rdev_for_each_list(rdev, tmp, (mddev)->disks)
 342
 343 #define rdev_for_each_rcu(rdev, mddev)                          \
 344         list_for_each_entry_rcu(rdev, &((mddev)->disks), same_set)
 345
 346 typedef struct mdk_thread_s {
 347         void                    (*run) (mddev_t *mddev);
 348         mddev_t                 *mddev;
 349         wait_queue_head_t       wqueue;
 350         unsigned long           flags;
 351         struct task_struct      *tsk;
 352         unsigned long           timeout;
 353 } mdk_thread_t;
 354
 355 #define THREAD_WAKEUP  0
 356
 357 #define __wait_event_lock_irq(wq, condition, lock, cmd)                 \
 358 do {                                                                    \
 359         wait_queue_t __wait;                                            \
 360         init_waitqueue_entry(&__wait, current);                         \
 361                                                                         \
 362         add_wait_queue(&wq, &__wait);                                   \
 363         for (;;) {                                                      \
 364                 set_current_state(TASK_UNINTERRUPTIBLE);                \
 365                 if (condition)                                          \
 366                         break;                                          \
 367                 spin_unlock_irq(&lock);                                 \
 368                 cmd;                                                    \
 369                 schedule();                                             \
 370                 spin_lock_irq(&lock);                                   \
 371         }                                                               \
 372         current->state = TASK_RUNNING;                                  \
 373         remove_wait_queue(&wq, &__wait);                                \
 374 } while (0)
 375
 376 #define wait_event_lock_irq(wq, condition, lock, cmd)                   \
 377 do {                                                                    \
 378         if (condition)                                                  \
 379                 break;                                                  \
 380         __wait_event_lock_irq(wq, condition, lock, cmd);                \
 381 } while (0)
 382
 383 static inline void safe_put_page(struct page *p)
 384 {
 385         if (p) put_page(p);
 386 }
 387
 388 #endif /* CONFIG_BLOCK */
 389 #endif
 390