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