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;    /* blocks scheduled */
 152         unsigned long                   resync_mark;    /* a recent timestamp */
 153         sector_t                        resync_mark_cnt;/* blocks written at resync_mark */
 154
 155         sector_t                        resync_max_sectors; /* may be set by personality */
 156
 157         sector_t                        resync_mismatches; /* count of sectors where
 158                                                             * parity/replica mismatch found
 159                                                             */
 160
 161         /* allow user-space to request suspension of IO to regions of the array */
 162         sector_t                        suspend_lo;
 163         sector_t                        suspend_hi;
 164         /* if zero, use the system-wide default */
 165         int                             sync_speed_min;
 166         int                             sync_speed_max;
 167
 168         int                             ok_start_degraded;
 169         /* recovery/resync flags
 170          * NEEDED:   we might need to start a resync/recover
 171          * RUNNING:  a thread is running, or about to be started
 172          * SYNC:     actually doing a resync, not a recovery
 173          * ERR:      and IO error was detected - abort the resync/recovery
 174          * INTR:     someone requested a (clean) early abort.
 175          * DONE:     thread is done and is waiting to be reaped
 176          * REQUEST:  user-space has requested a sync (used with SYNC)
 177          * CHECK:    user-space request for for check-only, no repair
 178          * RESHAPE:  A reshape is happening
 179          *
 180          * If neither SYNC or RESHAPE are set, then it is a recovery.
 181          */
 182 #define MD_RECOVERY_RUNNING     0
 183 #define MD_RECOVERY_SYNC        1
 184 #define MD_RECOVERY_ERR         2
 185 #define MD_RECOVERY_INTR        3
 186 #define MD_RECOVERY_DONE        4
 187 #define MD_RECOVERY_NEEDED      5
 188 #define MD_RECOVERY_REQUESTED   6
 189 #define MD_RECOVERY_CHECK       7
 190 #define MD_RECOVERY_RESHAPE     8
 191 #define MD_RECOVERY_FROZEN      9
 192
 193         unsigned long                   recovery;
 194
 195         int                             in_sync;        /* know to not need resync */
 196         struct mutex                    reconfig_mutex;
 197         atomic_t                        active;
 198
 199         int                             changed;        /* true if we might need to reread partition info */
 200         int                             degraded;       /* whether md should consider
 201                                                          * adding a spare
 202                                                          */
 203         int                             barriers_work;  /* initialised to true, cleared as soon
 204                                                          * as a barrier request to slave
 205                                                          * fails.  Only supported
 206                                                          */
 207         struct bio                      *biolist;       /* bios that need to be retried
 208                                                          * because BIO_RW_BARRIER is not supported
 209                                                          */
 210
 211         atomic_t                        recovery_active; /* blocks scheduled, but not written */
 212         wait_queue_head_t               recovery_wait;
 213         sector_t                        recovery_cp;
 214
 215         spinlock_t                      write_lock;
 216         wait_queue_head_t               sb_wait;        /* for waiting on superblock updates */
 217         atomic_t                        pending_writes; /* number of active superblock writes */
 218
 219         unsigned int                    safemode;       /* if set, update "clean" superblock
 220                                                          * when no writes pending.
 221                                                          */
 222         unsigned int                    safemode_delay;
 223         struct timer_list               safemode_timer;
 224         atomic_t                        writes_pending;
 225         request_queue_t                 *queue; /* for plugging ... */
 226
 227         atomic_t                        write_behind; /* outstanding async IO */
 228         unsigned int                    max_write_behind; /* 0 = sync */
 229
 230         struct bitmap                   *bitmap; /* the bitmap for the device */
 231         struct file                     *bitmap_file; /* the bitmap file */
 232         long                            bitmap_offset; /* offset from superblock of
 233                                                         * start of bitmap. May be
 234                                                         * negative, but not '0'
 235                                                         */
 236         long                            default_bitmap_offset; /* this is the offset to use when
 237                                                                 * hot-adding a bitmap.  It should
 238                                                                 * eventually be settable by sysfs.
 239                                                                 */
 240
 241         struct list_head                all_mddevs;
 242 };
 243
 244
 245 static inline void rdev_dec_pending(mdk_rdev_t *rdev, mddev_t *mddev)
 246 {
 247         int faulty = test_bit(Faulty, &rdev->flags);
 248         if (atomic_dec_and_test(&rdev->nr_pending) && faulty)
 249                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
 250 }
 251
 252 static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
 253 {
 254         atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
 255 }
 256
 257 struct mdk_personality
 258 {
 259         char *name;
 260         int level;
 261         struct list_head list;
 262         struct module *owner;
 263         int (*make_request)(request_queue_t *q, struct bio *bio);
 264         int (*run)(mddev_t *mddev);
 265         int (*stop)(mddev_t *mddev);
 266         void (*status)(struct seq_file *seq, mddev_t *mddev);
 267         /* error_handler must set ->faulty and clear ->in_sync
 268          * if appropriate, and should abort recovery if needed
 269          */
 270         void (*error_handler)(mddev_t *mddev, mdk_rdev_t *rdev);
 271         int (*hot_add_disk) (mddev_t *mddev, mdk_rdev_t *rdev);
 272         int (*hot_remove_disk) (mddev_t *mddev, int number);
 273         int (*spare_active) (mddev_t *mddev);
 274         sector_t (*sync_request)(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster);
 275         int (*resize) (mddev_t *mddev, sector_t sectors);
 276         int (*check_reshape) (mddev_t *mddev);
 277         int (*start_reshape) (mddev_t *mddev);
 278         int (*reconfig) (mddev_t *mddev, int layout, int chunk_size);
 279         /* quiesce moves between quiescence states
 280          * 0 - fully active
 281          * 1 - no new requests allowed
 282          * others - reserved
 283          */
 284         void (*quiesce) (mddev_t *mddev, int state);
 285 };
 286
 287
 288 struct md_sysfs_entry {
 289         struct attribute attr;
 290         ssize_t (*show)(mddev_t *, char *);
 291         ssize_t (*store)(mddev_t *, const char *, size_t);
 292 };
 293
 294
 295 static inline char * mdname (mddev_t * mddev)
 296 {
 297         return mddev->gendisk ? mddev->gendisk->disk_name : "mdX";
 298 }
 299
 300 /*
 301  * iterates through some rdev ringlist. It's safe to remove the
 302  * current 'rdev'. Dont touch 'tmp' though.
 303  */
 304 #define ITERATE_RDEV_GENERIC(head,rdev,tmp)                             \
 305                                                                         \
 306         for ((tmp) = (head).next;                                       \
 307                 (rdev) = (list_entry((tmp), mdk_rdev_t, same_set)),     \
 308                         (tmp) = (tmp)->next, (tmp)->prev != &(head)     \
 309                 ; )
 310 /*
 311  * iterates through the 'same array disks' ringlist
 312  */
 313 #define ITERATE_RDEV(mddev,rdev,tmp)                                    \
 314         ITERATE_RDEV_GENERIC((mddev)->disks,rdev,tmp)
 315
 316 /*
 317  * Iterates through 'pending RAID disks'
 318  */
 319 #define ITERATE_RDEV_PENDING(rdev,tmp)                                  \
 320         ITERATE_RDEV_GENERIC(pending_raid_disks,rdev,tmp)
 321
 322 typedef struct mdk_thread_s {
 323         void                    (*run) (mddev_t *mddev);
 324         mddev_t                 *mddev;
 325         wait_queue_head_t       wqueue;
 326         unsigned long           flags;
 327         struct task_struct      *tsk;
 328         unsigned long           timeout;
 329 } mdk_thread_t;
 330
 331 #define THREAD_WAKEUP  0
 332
 333 #define __wait_event_lock_irq(wq, condition, lock, cmd)                 \
 334 do {                                                                    \
 335         wait_queue_t __wait;                                            \
 336         init_waitqueue_entry(&__wait, current);                         \
 337                                                                         \
 338         add_wait_queue(&wq, &__wait);                                   \
 339         for (;;) {                                                      \
 340                 set_current_state(TASK_UNINTERRUPTIBLE);                \
 341                 if (condition)                                          \
 342                         break;                                          \
 343                 spin_unlock_irq(&lock);                                 \
 344                 cmd;                                                    \
 345                 schedule();                                             \
 346                 spin_lock_irq(&lock);                                   \
 347         }                                                               \
 348         current->state = TASK_RUNNING;                                  \
 349         remove_wait_queue(&wq, &__wait);                                \
 350 } while (0)
 351
 352 #define wait_event_lock_irq(wq, condition, lock, cmd)                   \
 353 do {                                                                    \
 354         if (condition)                                                  \
 355                 break;                                                  \
 356         __wait_event_lock_irq(wq, condition, lock, cmd);                \
 357 } while (0)
 358
 359 static inline void safe_put_page(struct page *p)
 360 {
 361         if (p) put_page(p);
 362 }
 363
 364 #endif
 365