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 LEVEL_MULTIPATH         (-4)
  22 #define LEVEL_LINEAR            (-1)
  23 #define LEVEL_FAULTY            (-5)
  24
  25 /* we need a value for 'no level specified' and 0
  26  * means 'raid0', so we need something else.  This is
  27  * for internal use only
  28  */
  29 #define LEVEL_NONE              (-1000000)
  30
  31 #define MaxSector (~(sector_t)0)
  32 #define MD_THREAD_NAME_MAX 14
  33
  34 typedef struct mddev_s mddev_t;
  35 typedef struct mdk_rdev_s mdk_rdev_t;
  36
  37 #define MAX_MD_DEVS  256        /* Max number of md dev */
  38
  39 /*
  40  * options passed in raidrun:
  41  */
  42
  43 /* Currently this must fix in an 'int' */
  44 #define MAX_CHUNK_SIZE (1<<30)
  45
  46 /*
  47  * MD's 'extended' device
  48  */
  49 struct mdk_rdev_s
  50 {
  51         struct list_head same_set;      /* RAID devices within the same set */
  52
  53         sector_t size;                  /* Device size (in blocks) */
  54         mddev_t *mddev;                 /* RAID array if running */
  55         unsigned long last_events;      /* IO event timestamp */
  56
  57         struct block_device *bdev;      /* block device handle */
  58
  59         struct page     *sb_page;
  60         int             sb_loaded;
  61         __u64           sb_events;
  62         sector_t        data_offset;    /* start of data in array */
  63         sector_t        sb_offset;
  64         int             sb_size;        /* bytes in the superblock */
  65         int             preferred_minor;        /* autorun support */
  66
  67         struct kobject  kobj;
  68
  69         /* A device can be in one of three states based on two flags:
  70          * Not working:   faulty==1 in_sync==0
  71          * Fully working: faulty==0 in_sync==1
  72          * Working, but not
  73          * in sync with array
  74          *                faulty==0 in_sync==0
  75          *
  76          * It can never have faulty==1, in_sync==1
  77          * This reduces the burden of testing multiple flags in many cases
  78          */
  79
  80         unsigned long   flags;
  81 #define Faulty          1               /* device is known to have a fault */
  82 #define In_sync         2               /* device is in_sync with rest of array */
  83 #define WriteMostly     4               /* Avoid reading if at all possible */
  84 #define BarriersNotsupp 5               /* BIO_RW_BARRIER is not supported */
  85
  86         int desc_nr;                    /* descriptor index in the superblock */
  87         int raid_disk;                  /* role of device in array */
  88         int saved_raid_disk;            /* role that device used to have in the
  89                                          * array and could again if we did a partial
  90                                          * resync from the bitmap
  91                                          */
  92         sector_t        recovery_offset;/* If this device has been partially
  93                                          * recovered, this is where we were
  94                                          * up to.
  95                                          */
  96
  97         atomic_t        nr_pending;     /* number of pending requests.
  98                                          * only maintained for arrays that
  99                                          * support hot removal
 100                                          */
 101         atomic_t        read_errors;    /* number of consecutive read errors that
 102                                          * we have tried to ignore.
 103                                          */
 104         atomic_t        corrected_errors; /* number of corrected read errors,
 105                                            * for reporting to userspace and storing
 106                                            * in superblock.
 107                                            */
 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         int                             sb_dirty;
 118         int                             ro;
 119
 120         struct gendisk                  *gendisk;
 121
 122         struct kobject                  kobj;
 123
 124         /* Superblock information */
 125         int                             major_version,
 126                                         minor_version,
 127                                         patch_version;
 128         int                             persistent;
 129         int                             chunk_size;
 130         time_t                          ctime, utime;
 131         int                             level, layout;
 132         char                            clevel[16];
 133         int                             raid_disks;
 134         int                             max_disks;
 135         sector_t                        size; /* used size of component devices */
 136         sector_t                        array_size; /* exported array size */
 137         __u64                           events;
 138
 139         char                            uuid[16];
 140
 141         /* If the array is being reshaped, we need to record the
 142          * new shape and an indication of where we are up to.
 143          * This is written to the superblock.
 144          * If reshape_position is MaxSector, then no reshape is happening (yet).
 145          */
 146         sector_t                        reshape_position;
 147         int                             delta_disks, new_level, new_layout, new_chunk;
 148
 149         struct mdk_thread_s             *thread;        /* management thread */
 150         struct mdk_thread_s             *sync_thread;   /* doing resync or reconstruct */
 151         sector_t                        curr_resync;    /* last block scheduled */
 152         unsigned long                   resync_mark;    /* a recent timestamp */
 153         sector_t                        resync_mark_cnt;/* blocks written at resync_mark */
 154         sector_t                        curr_mark_cnt; /* blocks scheduled now */
 155
 156         sector_t                        resync_max_sectors; /* may be set by personality */
 157
 158         sector_t                        resync_mismatches; /* count of sectors where
 159                                                             * parity/replica mismatch found
 160                                                             */
 161
 162         /* allow user-space to request suspension of IO to regions of the array */
 163         sector_t                        suspend_lo;
 164         sector_t                        suspend_hi;
 165         /* if zero, use the system-wide default */
 166         int                             sync_speed_min;
 167         int                             sync_speed_max;
 168
 169         int                             ok_start_degraded;
 170         /* recovery/resync flags
 171          * NEEDED:   we might need to start a resync/recover
 172          * RUNNING:  a thread is running, or about to be started
 173          * SYNC:     actually doing a resync, not a recovery
 174          * ERR:      and IO error was detected - abort the resync/recovery
 175          * INTR:     someone requested a (clean) early abort.
 176          * DONE:     thread is done and is waiting to be reaped
 177          * REQUEST:  user-space has requested a sync (used with SYNC)
 178          * CHECK:    user-space request for for check-only, no repair
 179          * RESHAPE:  A reshape is happening
 180          *
 181          * If neither SYNC or RESHAPE are set, then it is a recovery.
 182          */
 183 #define MD_RECOVERY_RUNNING     0
 184 #define MD_RECOVERY_SYNC        1
 185 #define MD_RECOVERY_ERR         2
 186 #define MD_RECOVERY_INTR        3
 187 #define MD_RECOVERY_DONE        4
 188 #define MD_RECOVERY_NEEDED      5
 189 #define MD_RECOVERY_REQUESTED   6
 190 #define MD_RECOVERY_CHECK       7
 191 #define MD_RECOVERY_RESHAPE     8
 192 #define MD_RECOVERY_FROZEN      9
 193
 194         unsigned long                   recovery;
 195
 196         int                             in_sync;        /* know to not need resync */
 197         struct mutex                    reconfig_mutex;
 198         atomic_t                        active;
 199
 200         int                             changed;        /* true if we might need to reread partition info */
 201         int                             degraded;       /* whether md should consider
 202                                                          * adding a spare
 203                                                          */
 204         int                             barriers_work;  /* initialised to true, cleared as soon
 205                                                          * as a barrier request to slave
 206                                                          * fails.  Only supported
 207                                                          */
 208         struct bio                      *biolist;       /* bios that need to be retried
 209                                                          * because BIO_RW_BARRIER is not supported
 210                                                          */
 211
 212         atomic_t                        recovery_active; /* blocks scheduled, but not written */
 213         wait_queue_head_t               recovery_wait;
 214         sector_t                        recovery_cp;
 215
 216         spinlock_t                      write_lock;
 217         wait_queue_head_t               sb_wait;        /* for waiting on superblock updates */
 218         atomic_t                        pending_writes; /* number of active superblock writes */
 219
 220         unsigned int                    safemode;       /* if set, update "clean" superblock
 221                                                          * when no writes pending.
 222                                                          */
 223         unsigned int                    safemode_delay;
 224         struct timer_list               safemode_timer;
 225         atomic_t                        writes_pending;
 226         request_queue_t                 *queue; /* for plugging ... */
 227
 228         atomic_t                        write_behind; /* outstanding async IO */
 229         unsigned int                    max_write_behind; /* 0 = sync */
 230
 231         struct bitmap                   *bitmap; /* the bitmap for the device */
 232         struct file                     *bitmap_file; /* the bitmap file */
 233         long                            bitmap_offset; /* offset from superblock of
 234                                                         * start of bitmap. May be
 235                                                         * negative, but not '0'
 236                                                         */
 237         long                            default_bitmap_offset; /* this is the offset to use when
 238                                                                 * hot-adding a bitmap.  It should
 239                                                                 * eventually be settable by sysfs.
 240                                                                 */
 241
 242         struct list_head                all_mddevs;
 243 };
 244
 245
 246 static inline void rdev_dec_pending(mdk_rdev_t *rdev, mddev_t *mddev)
 247 {
 248         int faulty = test_bit(Faulty, &rdev->flags);
 249         if (atomic_dec_and_test(&rdev->nr_pending) && faulty)
 250                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
 251 }
 252
 253 static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
 254 {
 255         atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
 256 }
 257
 258 struct mdk_personality
 259 {
 260         char *name;
 261         int level;
 262         struct list_head list;
 263         struct module *owner;
 264         int (*make_request)(request_queue_t *q, struct bio *bio);
 265         int (*run)(mddev_t *mddev);
 266         int (*stop)(mddev_t *mddev);
 267         void (*status)(struct seq_file *seq, mddev_t *mddev);
 268         /* error_handler must set ->faulty and clear ->in_sync
 269          * if appropriate, and should abort recovery if needed
 270          */
 271         void (*error_handler)(mddev_t *mddev, mdk_rdev_t *rdev);
 272         int (*hot_add_disk) (mddev_t *mddev, mdk_rdev_t *rdev);
 273         int (*hot_remove_disk) (mddev_t *mddev, int number);
 274         int (*spare_active) (mddev_t *mddev);
 275         sector_t (*sync_request)(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster);
 276         int (*resize) (mddev_t *mddev, sector_t sectors);
 277         int (*check_reshape) (mddev_t *mddev);
 278         int (*start_reshape) (mddev_t *mddev);
 279         int (*reconfig) (mddev_t *mddev, int layout, int chunk_size);
 280         /* quiesce moves between quiescence states
 281          * 0 - fully active
 282          * 1 - no new requests allowed
 283          * others - reserved
 284          */
 285         void (*quiesce) (mddev_t *mddev, int state);
 286 };
 287
 288
 289 struct md_sysfs_entry {
 290         struct attribute attr;
 291         ssize_t (*show)(mddev_t *, char *);
 292         ssize_t (*store)(mddev_t *, const char *, size_t);
 293 };
 294
 295
 296 static inline char * mdname (mddev_t * mddev)
 297 {
 298         return mddev->gendisk ? mddev->gendisk->disk_name : "mdX";
 299 }
 300
 301 /*
 302  * iterates through some rdev ringlist. It's safe to remove the
 303  * current 'rdev'. Dont touch 'tmp' though.
 304  */
 305 #define ITERATE_RDEV_GENERIC(head,rdev,tmp)                             \
 306                                                                         \
 307         for ((tmp) = (head).next;                                       \
 308                 (rdev) = (list_entry((tmp), mdk_rdev_t, same_set)),     \
 309                         (tmp) = (tmp)->next, (tmp)->prev != &(head)     \
 310                 ; )
 311 /*
 312  * iterates through the 'same array disks' ringlist
 313  */
 314 #define ITERATE_RDEV(mddev,rdev,tmp)                                    \
 315         ITERATE_RDEV_GENERIC((mddev)->disks,rdev,tmp)
 316
 317 /*
 318  * Iterates through 'pending RAID disks'
 319  */
 320 #define ITERATE_RDEV_PENDING(rdev,tmp)                                  \
 321         ITERATE_RDEV_GENERIC(pending_raid_disks,rdev,tmp)
 322
 323 typedef struct mdk_thread_s {
 324         void                    (*run) (mddev_t *mddev);
 325         mddev_t                 *mddev;
 326         wait_queue_head_t       wqueue;
 327         unsigned long           flags;
 328         struct task_struct      *tsk;
 329         unsigned long           timeout;
 330 } mdk_thread_t;
 331
 332 #define THREAD_WAKEUP  0
 333
 334 #define __wait_event_lock_irq(wq, condition, lock, cmd)                 \
 335 do {                                                                    \
 336         wait_queue_t __wait;                                            \
 337         init_waitqueue_entry(&__wait, current);                         \
 338                                                                         \
 339         add_wait_queue(&wq, &__wait);                                   \
 340         for (;;) {                                                      \
 341                 set_current_state(TASK_UNINTERRUPTIBLE);                \
 342                 if (condition)                                          \
 343                         break;                                          \
 344                 spin_unlock_irq(&lock);                                 \
 345                 cmd;                                                    \
 346                 schedule();                                             \
 347                 spin_lock_irq(&lock);                                   \
 348         }                                                               \
 349         current->state = TASK_RUNNING;                                  \
 350         remove_wait_queue(&wq, &__wait);                                \
 351 } while (0)
 352
 353 #define wait_event_lock_irq(wq, condition, lock, cmd)                   \
 354 do {                                                                    \
 355         if (condition)                                                  \
 356                 break;                                                  \
 357         __wait_event_lock_irq(wq, condition, lock, cmd);                \
 358 } while (0)
 359
 360 static inline void safe_put_page(struct page *p)
 361 {
 362         if (p) put_page(p);
 363 }
 364
 365 #endif
 366