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         unsigned 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_offset;
  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
  85         int desc_nr;                    /* descriptor index in the superblock */
  86         int raid_disk;                  /* role of device in array */
  87         int saved_raid_disk;            /* role that device used to have in the
  88                                          * array and could again if we did a partial
  89                                          * resync from the bitmap
  90                                          */
  91         sector_t        recovery_offset;/* If this device has been partially
  92                                          * recovered, this is where we were
  93                                          * up to.
  94                                          */
  95
  96         atomic_t        nr_pending;     /* number of pending requests.
  97                                          * only maintained for arrays that
  98                                          * support hot removal
  99                                          */
 100         atomic_t        read_errors;    /* number of consecutive read errors that
 101                                          * we have tried to ignore.
 102                                          */
 103         atomic_t        corrected_errors; /* number of corrected read errors,
 104                                            * for reporting to userspace and storing
 105                                            * in superblock.
 106                                            */
 107 };
 108
 109 struct mddev_s
 110 {
 111         void                            *private;
 112         struct mdk_personality          *pers;
 113         dev_t                           unit;
 114         int                             md_minor;
 115         struct list_head                disks;
 116         unsigned long                   flags;
 117 #define MD_CHANGE_DEVS  0       /* Some device status has changed */
 118 #define MD_CHANGE_CLEAN 1       /* transition to or from 'clean' */
 119 #define MD_CHANGE_PENDING 2     /* superblock update in progress */
 120
 121         int                             ro;
 122
 123         struct gendisk                  *gendisk;
 124
 125         struct kobject                  kobj;
 126
 127         /* Superblock information */
 128         int                             major_version,
 129                                         minor_version,
 130                                         patch_version;
 131         int                             persistent;
 132         int                             chunk_size;
 133         time_t                          ctime, utime;
 134         int                             level, layout;
 135         char                            clevel[16];
 136         int                             raid_disks;
 137         int                             max_disks;
 138         sector_t                        size; /* used size of component devices */
 139         sector_t                        array_size; /* exported array size */
 140         __u64                           events;
 141
 142         char                            uuid[16];
 143
 144         /* If the array is being reshaped, we need to record the
 145          * new shape and an indication of where we are up to.
 146          * This is written to the superblock.
 147          * If reshape_position is MaxSector, then no reshape is happening (yet).
 148          */
 149         sector_t                        reshape_position;
 150         int                             delta_disks, new_level, new_layout, new_chunk;
 151
 152         struct mdk_thread_s             *thread;        /* management thread */
 153         struct mdk_thread_s             *sync_thread;   /* doing resync or reconstruct */
 154         sector_t                        curr_resync;    /* last block scheduled */
 155         unsigned long                   resync_mark;    /* a recent timestamp */
 156         sector_t                        resync_mark_cnt;/* blocks written at resync_mark */
 157         sector_t                        curr_mark_cnt; /* blocks scheduled now */
 158
 159         sector_t                        resync_max_sectors; /* may be set by personality */
 160
 161         sector_t                        resync_mismatches; /* count of sectors where
 162                                                             * parity/replica mismatch found
 163                                                             */
 164
 165         /* allow user-space to request suspension of IO to regions of the array */
 166         sector_t                        suspend_lo;
 167         sector_t                        suspend_hi;
 168         /* if zero, use the system-wide default */
 169         int                             sync_speed_min;
 170         int                             sync_speed_max;
 171
 172         int                             ok_start_degraded;
 173         /* recovery/resync flags
 174          * NEEDED:   we might need to start a resync/recover
 175          * RUNNING:  a thread is running, or about to be started
 176          * SYNC:     actually doing a resync, not a recovery
 177          * ERR:      and IO error was detected - abort the resync/recovery
 178          * INTR:     someone requested a (clean) early abort.
 179          * DONE:     thread is done and is waiting to be reaped
 180          * REQUEST:  user-space has requested a sync (used with SYNC)
 181          * CHECK:    user-space request for for check-only, no repair
 182          * RESHAPE:  A reshape is happening
 183          *
 184          * If neither SYNC or RESHAPE are set, then it is a recovery.
 185          */
 186 #define MD_RECOVERY_RUNNING     0
 187 #define MD_RECOVERY_SYNC        1
 188 #define MD_RECOVERY_ERR         2
 189 #define MD_RECOVERY_INTR        3
 190 #define MD_RECOVERY_DONE        4
 191 #define MD_RECOVERY_NEEDED      5
 192 #define MD_RECOVERY_REQUESTED   6
 193 #define MD_RECOVERY_CHECK       7
 194 #define MD_RECOVERY_RESHAPE     8
 195 #define MD_RECOVERY_FROZEN      9
 196
 197         unsigned long                   recovery;
 198
 199         int                             in_sync;        /* know to not need resync */
 200         struct mutex                    reconfig_mutex;
 201         atomic_t                        active;
 202
 203         int                             changed;        /* true if we might need to reread partition info */
 204         int                             degraded;       /* whether md should consider
 205                                                          * adding a spare
 206                                                          */
 207         int                             barriers_work;  /* initialised to true, cleared as soon
 208                                                          * as a barrier request to slave
 209                                                          * fails.  Only supported
 210                                                          */
 211         struct bio                      *biolist;       /* bios that need to be retried
 212                                                          * because BIO_RW_BARRIER is not supported
 213                                                          */
 214
 215         atomic_t                        recovery_active; /* blocks scheduled, but not written */
 216         wait_queue_head_t               recovery_wait;
 217         sector_t                        recovery_cp;
 218
 219         spinlock_t                      write_lock;
 220         wait_queue_head_t               sb_wait;        /* for waiting on superblock updates */
 221         atomic_t                        pending_writes; /* number of active superblock writes */
 222
 223         unsigned int                    safemode;       /* if set, update "clean" superblock
 224                                                          * when no writes pending.
 225                                                          */
 226         unsigned int                    safemode_delay;
 227         struct timer_list               safemode_timer;
 228         atomic_t                        writes_pending;
 229         request_queue_t                 *queue; /* for plugging ... */
 230
 231         atomic_t                        write_behind; /* outstanding async IO */
 232         unsigned int                    max_write_behind; /* 0 = sync */
 233
 234         struct bitmap                   *bitmap; /* the bitmap for the device */
 235         struct file                     *bitmap_file; /* the bitmap file */
 236         long                            bitmap_offset; /* offset from superblock of
 237                                                         * start of bitmap. May be
 238                                                         * negative, but not '0'
 239                                                         */
 240         long                            default_bitmap_offset; /* this is the offset to use when
 241                                                                 * hot-adding a bitmap.  It should
 242                                                                 * eventually be settable by sysfs.
 243                                                                 */
 244
 245         struct list_head                all_mddevs;
 246 };
 247
 248
 249 static inline void rdev_dec_pending(mdk_rdev_t *rdev, mddev_t *mddev)
 250 {
 251         int faulty = test_bit(Faulty, &rdev->flags);
 252         if (atomic_dec_and_test(&rdev->nr_pending) && faulty)
 253                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
 254 }
 255
 256 static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
 257 {
 258         atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
 259 }
 260
 261 struct mdk_personality
 262 {
 263         char *name;
 264         int level;
 265         struct list_head list;
 266         struct module *owner;
 267         int (*make_request)(request_queue_t *q, struct bio *bio);
 268         int (*run)(mddev_t *mddev);
 269         int (*stop)(mddev_t *mddev);
 270         void (*status)(struct seq_file *seq, mddev_t *mddev);
 271         /* error_handler must set ->faulty and clear ->in_sync
 272          * if appropriate, and should abort recovery if needed
 273          */
 274         void (*error_handler)(mddev_t *mddev, mdk_rdev_t *rdev);
 275         int (*hot_add_disk) (mddev_t *mddev, mdk_rdev_t *rdev);
 276         int (*hot_remove_disk) (mddev_t *mddev, int number);
 277         int (*spare_active) (mddev_t *mddev);
 278         sector_t (*sync_request)(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster);
 279         int (*resize) (mddev_t *mddev, sector_t sectors);
 280         int (*check_reshape) (mddev_t *mddev);
 281         int (*start_reshape) (mddev_t *mddev);
 282         int (*reconfig) (mddev_t *mddev, int layout, int chunk_size);
 283         /* quiesce moves between quiescence states
 284          * 0 - fully active
 285          * 1 - no new requests allowed
 286          * others - reserved
 287          */
 288         void (*quiesce) (mddev_t *mddev, int state);
 289 };
 290
 291
 292 struct md_sysfs_entry {
 293         struct attribute attr;
 294         ssize_t (*show)(mddev_t *, char *);
 295         ssize_t (*store)(mddev_t *, const char *, size_t);
 296 };
 297
 298
 299 static inline char * mdname (mddev_t * mddev)
 300 {
 301         return mddev->gendisk ? mddev->gendisk->disk_name : "mdX";
 302 }
 303
 304 /*
 305  * iterates through some rdev ringlist. It's safe to remove the
 306  * current 'rdev'. Dont touch 'tmp' though.
 307  */
 308 #define ITERATE_RDEV_GENERIC(head,rdev,tmp)                             \
 309                                                                         \
 310         for ((tmp) = (head).next;                                       \
 311                 (rdev) = (list_entry((tmp), mdk_rdev_t, same_set)),     \
 312                         (tmp) = (tmp)->next, (tmp)->prev != &(head)     \
 313                 ; )
 314 /*
 315  * iterates through the 'same array disks' ringlist
 316  */
 317 #define ITERATE_RDEV(mddev,rdev,tmp)                                    \
 318         ITERATE_RDEV_GENERIC((mddev)->disks,rdev,tmp)
 319
 320 /*
 321  * Iterates through 'pending RAID disks'
 322  */
 323 #define ITERATE_RDEV_PENDING(rdev,tmp)                                  \
 324         ITERATE_RDEV_GENERIC(pending_raid_disks,rdev,tmp)
 325
 326 typedef struct mdk_thread_s {
 327         void                    (*run) (mddev_t *mddev);
 328         mddev_t                 *mddev;
 329         wait_queue_head_t       wqueue;
 330         unsigned long           flags;
 331         struct task_struct      *tsk;
 332         unsigned long           timeout;
 333 } mdk_thread_t;
 334
 335 #define THREAD_WAKEUP  0
 336
 337 #define __wait_event_lock_irq(wq, condition, lock, cmd)                 \
 338 do {                                                                    \
 339         wait_queue_t __wait;                                            \
 340         init_waitqueue_entry(&__wait, current);                         \
 341                                                                         \
 342         add_wait_queue(&wq, &__wait);                                   \
 343         for (;;) {                                                      \
 344                 set_current_state(TASK_UNINTERRUPTIBLE);                \
 345                 if (condition)                                          \
 346                         break;                                          \
 347                 spin_unlock_irq(&lock);                                 \
 348                 cmd;                                                    \
 349                 schedule();                                             \
 350                 spin_lock_irq(&lock);                                   \
 351         }                                                               \
 352         current->state = TASK_RUNNING;                                  \
 353         remove_wait_queue(&wq, &__wait);                                \
 354 } while (0)
 355
 356 #define wait_event_lock_irq(wq, condition, lock, cmd)                   \
 357 do {                                                                    \
 358         if (condition)                                                  \
 359                 break;                                                  \
 360         __wait_event_lock_irq(wq, condition, lock, cmd);                \
 361 } while (0)
 362
 363 static inline void safe_put_page(struct page *p)
 364 {
 365         if (p) put_page(p);
 366 }
 367
 368 #endif /* CONFIG_BLOCK */
 369 #endif
 370