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 #define MD_THREAD_NAME_MAX 14
  35
  36 typedef struct mddev_s mddev_t;
  37 typedef struct mdk_rdev_s mdk_rdev_t;
  38
  39 #define MAX_MD_DEVS  256        /* Max number of md dev */
  40
  41 /*
  42  * options passed in raidrun:
  43  */
  44
  45 /* Currently this must fix in an 'int' */
  46 #define MAX_CHUNK_SIZE (1<<30)
  47
  48 /*
  49  * MD's 'extended' device
  50  */
  51 struct mdk_rdev_s
  52 {
  53         struct list_head same_set;      /* RAID devices within the same set */
  54
  55         sector_t size;                  /* Device size (in blocks) */
  56         mddev_t *mddev;                 /* RAID array if running */
  57         unsigned long last_events;      /* IO event timestamp */
  58
  59         struct block_device *bdev;      /* block device handle */
  60
  61         struct page     *sb_page;
  62         int             sb_loaded;
  63         __u64           sb_events;
  64         sector_t        data_offset;    /* start of data in array */
  65         sector_t        sb_offset;
  66         int             sb_size;        /* bytes in the superblock */
  67         int             preferred_minor;        /* autorun support */
  68
  69         struct kobject  kobj;
  70
  71         /* A device can be in one of three states based on two flags:
  72          * Not working:   faulty==1 in_sync==0
  73          * Fully working: faulty==0 in_sync==1
  74          * Working, but not
  75          * in sync with array
  76          *                faulty==0 in_sync==0
  77          *
  78          * It can never have faulty==1, in_sync==1
  79          * This reduces the burden of testing multiple flags in many cases
  80          */
  81
  82         unsigned long   flags;
  83 #define Faulty          1               /* device is known to have a fault */
  84 #define In_sync         2               /* device is in_sync with rest of array */
  85 #define WriteMostly     4               /* Avoid reading if at all possible */
  86 #define BarriersNotsupp 5               /* BIO_RW_BARRIER is not supported */
  87
  88         int desc_nr;                    /* descriptor index in the superblock */
  89         int raid_disk;                  /* role of device in array */
  90         int saved_raid_disk;            /* role that device used to have in the
  91                                          * array and could again if we did a partial
  92                                          * resync from the bitmap
  93                                          */
  94         sector_t        recovery_offset;/* If this device has been partially
  95                                          * recovered, this is where we were
  96                                          * up to.
  97                                          */
  98
  99         atomic_t        nr_pending;     /* number of pending requests.
 100                                          * only maintained for arrays that
 101                                          * support hot removal
 102                                          */
 103         atomic_t        read_errors;    /* number of consecutive read errors that
 104                                          * we have tried to ignore.
 105                                          */
 106         atomic_t        corrected_errors; /* number of corrected read errors,
 107                                            * for reporting to userspace and storing
 108                                            * in superblock.
 109                                            */
 110 };
 111
 112 struct mddev_s
 113 {
 114         void                            *private;
 115         struct mdk_personality          *pers;
 116         dev_t                           unit;
 117         int                             md_minor;
 118         struct list_head                disks;
 119         int                             sb_dirty;
 120         int                             ro;
 121
 122         struct gendisk                  *gendisk;
 123
 124         struct kobject                  kobj;
 125
 126         /* Superblock information */
 127         int                             major_version,
 128                                         minor_version,
 129                                         patch_version;
 130         int                             persistent;
 131         int                             chunk_size;
 132         time_t                          ctime, utime;
 133         int                             level, layout;
 134         char                            clevel[16];
 135         int                             raid_disks;
 136         int                             max_disks;
 137         sector_t                        size; /* used size of component devices */
 138         sector_t                        array_size; /* exported array size */
 139         __u64                           events;
 140
 141         char                            uuid[16];
 142
 143         /* If the array is being reshaped, we need to record the
 144          * new shape and an indication of where we are up to.
 145          * This is written to the superblock.
 146          * If reshape_position is MaxSector, then no reshape is happening (yet).
 147          */
 148         sector_t                        reshape_position;
 149         int                             delta_disks, new_level, new_layout, new_chunk;
 150
 151         struct mdk_thread_s             *thread;        /* management thread */
 152         struct mdk_thread_s             *sync_thread;   /* doing resync or reconstruct */
 153         sector_t                        curr_resync;    /* last block scheduled */
 154         unsigned long                   resync_mark;    /* a recent timestamp */
 155         sector_t                        resync_mark_cnt;/* blocks written at resync_mark */
 156         sector_t                        curr_mark_cnt; /* blocks scheduled now */
 157
 158         sector_t                        resync_max_sectors; /* may be set by personality */
 159
 160         sector_t                        resync_mismatches; /* count of sectors where
 161                                                             * parity/replica mismatch found
 162                                                             */
 163
 164         /* allow user-space to request suspension of IO to regions of the array */
 165         sector_t                        suspend_lo;
 166         sector_t                        suspend_hi;
 167         /* if zero, use the system-wide default */
 168         int                             sync_speed_min;
 169         int                             sync_speed_max;
 170
 171         int                             ok_start_degraded;
 172         /* recovery/resync flags
 173          * NEEDED:   we might need to start a resync/recover
 174          * RUNNING:  a thread is running, or about to be started
 175          * SYNC:     actually doing a resync, not a recovery
 176          * ERR:      and IO error was detected - abort the resync/recovery
 177          * INTR:     someone requested a (clean) early abort.
 178          * DONE:     thread is done and is waiting to be reaped
 179          * REQUEST:  user-space has requested a sync (used with SYNC)
 180          * CHECK:    user-space request for for check-only, no repair
 181          * RESHAPE:  A reshape is happening
 182          *
 183          * If neither SYNC or RESHAPE are set, then it is a recovery.
 184          */
 185 #define MD_RECOVERY_RUNNING     0
 186 #define MD_RECOVERY_SYNC        1
 187 #define MD_RECOVERY_ERR         2
 188 #define MD_RECOVERY_INTR        3
 189 #define MD_RECOVERY_DONE        4
 190 #define MD_RECOVERY_NEEDED      5
 191 #define MD_RECOVERY_REQUESTED   6
 192 #define MD_RECOVERY_CHECK       7
 193 #define MD_RECOVERY_RESHAPE     8
 194 #define MD_RECOVERY_FROZEN      9
 195
 196         unsigned long                   recovery;
 197
 198         int                             in_sync;        /* know to not need resync */
 199         struct mutex                    reconfig_mutex;
 200         atomic_t                        active;
 201
 202         int                             changed;        /* true if we might need to reread partition info */
 203         int                             degraded;       /* whether md should consider
 204                                                          * adding a spare
 205                                                          */
 206         int                             barriers_work;  /* initialised to true, cleared as soon
 207                                                          * as a barrier request to slave
 208                                                          * fails.  Only supported
 209                                                          */
 210         struct bio                      *biolist;       /* bios that need to be retried
 211                                                          * because BIO_RW_BARRIER is not supported
 212                                                          */
 213
 214         atomic_t                        recovery_active; /* blocks scheduled, but not written */
 215         wait_queue_head_t               recovery_wait;
 216         sector_t                        recovery_cp;
 217
 218         spinlock_t                      write_lock;
 219         wait_queue_head_t               sb_wait;        /* for waiting on superblock updates */
 220         atomic_t                        pending_writes; /* number of active superblock writes */
 221
 222         unsigned int                    safemode;       /* if set, update "clean" superblock
 223                                                          * when no writes pending.
 224                                                          */
 225         unsigned int                    safemode_delay;
 226         struct timer_list               safemode_timer;
 227         atomic_t                        writes_pending;
 228         request_queue_t                 *queue; /* for plugging ... */
 229
 230         atomic_t                        write_behind; /* outstanding async IO */
 231         unsigned int                    max_write_behind; /* 0 = sync */
 232
 233         struct bitmap                   *bitmap; /* the bitmap for the device */
 234         struct file                     *bitmap_file; /* the bitmap file */
 235         long                            bitmap_offset; /* offset from superblock of
 236                                                         * start of bitmap. May be
 237                                                         * negative, but not '0'
 238                                                         */
 239         long                            default_bitmap_offset; /* this is the offset to use when
 240                                                                 * hot-adding a bitmap.  It should
 241                                                                 * eventually be settable by sysfs.
 242                                                                 */
 243
 244         struct list_head                all_mddevs;
 245 };
 246
 247
 248 static inline void rdev_dec_pending(mdk_rdev_t *rdev, mddev_t *mddev)
 249 {
 250         int faulty = test_bit(Faulty, &rdev->flags);
 251         if (atomic_dec_and_test(&rdev->nr_pending) && faulty)
 252                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
 253 }
 254
 255 static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
 256 {
 257         atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
 258 }
 259
 260 struct mdk_personality
 261 {
 262         char *name;
 263         int level;
 264         struct list_head list;
 265         struct module *owner;
 266         int (*make_request)(request_queue_t *q, struct bio *bio);
 267         int (*run)(mddev_t *mddev);
 268         int (*stop)(mddev_t *mddev);
 269         void (*status)(struct seq_file *seq, mddev_t *mddev);
 270         /* error_handler must set ->faulty and clear ->in_sync
 271          * if appropriate, and should abort recovery if needed
 272          */
 273         void (*error_handler)(mddev_t *mddev, mdk_rdev_t *rdev);
 274         int (*hot_add_disk) (mddev_t *mddev, mdk_rdev_t *rdev);
 275         int (*hot_remove_disk) (mddev_t *mddev, int number);
 276         int (*spare_active) (mddev_t *mddev);
 277         sector_t (*sync_request)(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster);
 278         int (*resize) (mddev_t *mddev, sector_t sectors);
 279         int (*check_reshape) (mddev_t *mddev);
 280         int (*start_reshape) (mddev_t *mddev);
 281         int (*reconfig) (mddev_t *mddev, int layout, int chunk_size);
 282         /* quiesce moves between quiescence states
 283          * 0 - fully active
 284          * 1 - no new requests allowed
 285          * others - reserved
 286          */
 287         void (*quiesce) (mddev_t *mddev, int state);
 288 };
 289
 290
 291 struct md_sysfs_entry {
 292         struct attribute attr;
 293         ssize_t (*show)(mddev_t *, char *);
 294         ssize_t (*store)(mddev_t *, const char *, size_t);
 295 };
 296
 297
 298 static inline char * mdname (mddev_t * mddev)
 299 {
 300         return mddev->gendisk ? mddev->gendisk->disk_name : "mdX";
 301 }
 302
 303 /*
 304  * iterates through some rdev ringlist. It's safe to remove the
 305  * current 'rdev'. Dont touch 'tmp' though.
 306  */
 307 #define ITERATE_RDEV_GENERIC(head,rdev,tmp)                             \
 308                                                                         \
 309         for ((tmp) = (head).next;                                       \
 310                 (rdev) = (list_entry((tmp), mdk_rdev_t, same_set)),     \
 311                         (tmp) = (tmp)->next, (tmp)->prev != &(head)     \
 312                 ; )
 313 /*
 314  * iterates through the 'same array disks' ringlist
 315  */
 316 #define ITERATE_RDEV(mddev,rdev,tmp)                                    \
 317         ITERATE_RDEV_GENERIC((mddev)->disks,rdev,tmp)
 318
 319 /*
 320  * Iterates through 'pending RAID disks'
 321  */
 322 #define ITERATE_RDEV_PENDING(rdev,tmp)                                  \
 323         ITERATE_RDEV_GENERIC(pending_raid_disks,rdev,tmp)
 324
 325 typedef struct mdk_thread_s {
 326         void                    (*run) (mddev_t *mddev);
 327         mddev_t                 *mddev;
 328         wait_queue_head_t       wqueue;
 329         unsigned long           flags;
 330         struct task_struct      *tsk;
 331         unsigned long           timeout;
 332 } mdk_thread_t;
 333
 334 #define THREAD_WAKEUP  0
 335
 336 #define __wait_event_lock_irq(wq, condition, lock, cmd)                 \
 337 do {                                                                    \
 338         wait_queue_t __wait;                                            \
 339         init_waitqueue_entry(&__wait, current);                         \
 340                                                                         \
 341         add_wait_queue(&wq, &__wait);                                   \
 342         for (;;) {                                                      \
 343                 set_current_state(TASK_UNINTERRUPTIBLE);                \
 344                 if (condition)                                          \
 345                         break;                                          \
 346                 spin_unlock_irq(&lock);                                 \
 347                 cmd;                                                    \
 348                 schedule();                                             \
 349                 spin_lock_irq(&lock);                                   \
 350         }                                                               \
 351         current->state = TASK_RUNNING;                                  \
 352         remove_wait_queue(&wq, &__wait);                                \
 353 } while (0)
 354
 355 #define wait_event_lock_irq(wq, condition, lock, cmd)                   \
 356 do {                                                                    \
 357         if (condition)                                                  \
 358                 break;                                                  \
 359         __wait_event_lock_irq(wq, condition, lock, cmd);                \
 360 } while (0)
 361
 362 static inline void safe_put_page(struct page *p)
 363 {
 364         if (p) put_page(p);
 365 }
 366
 367 #endif /* CONFIG_BLOCK */
 368 #endif
 369