]> www.pilppa.org Git - linux-2.6-omap-h63xx.git/blobdiff - drivers/md/md.h
Merge branch 'omap-pool'
[linux-2.6-omap-h63xx.git] / drivers / md / md.h
diff --git a/drivers/md/md.h b/drivers/md/md.h
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@@ -0,0 +1,436 @@
+/*
+   md_k.h : kernel internal structure of the Linux MD driver
+          Copyright (C) 1996-98 Ingo Molnar, Gadi Oxman
+         
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+   
+   You should have received a copy of the GNU General Public License
+   (for example /usr/src/linux/COPYING); if not, write to the Free
+   Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  
+*/
+
+#ifndef _MD_K_H
+#define _MD_K_H
+
+#ifdef CONFIG_BLOCK
+
+#define MaxSector (~(sector_t)0)
+
+typedef struct mddev_s mddev_t;
+typedef struct mdk_rdev_s mdk_rdev_t;
+
+/*
+ * options passed in raidrun:
+ */
+
+/* Currently this must fit in an 'int' */
+#define MAX_CHUNK_SIZE (1<<30)
+
+/*
+ * MD's 'extended' device
+ */
+struct mdk_rdev_s
+{
+       struct list_head same_set;      /* RAID devices within the same set */
+
+       sector_t sectors;               /* Device size (in 512bytes sectors) */
+       mddev_t *mddev;                 /* RAID array if running */
+       int last_events;                /* IO event timestamp */
+
+       struct block_device *bdev;      /* block device handle */
+
+       struct page     *sb_page;
+       int             sb_loaded;
+       __u64           sb_events;
+       sector_t        data_offset;    /* start of data in array */
+       sector_t        sb_start;       /* offset of the super block (in 512byte sectors) */
+       int             sb_size;        /* bytes in the superblock */
+       int             preferred_minor;        /* autorun support */
+
+       struct kobject  kobj;
+
+       /* A device can be in one of three states based on two flags:
+        * Not working:   faulty==1 in_sync==0
+        * Fully working: faulty==0 in_sync==1
+        * Working, but not
+        * in sync with array
+        *                faulty==0 in_sync==0
+        *
+        * It can never have faulty==1, in_sync==1
+        * This reduces the burden of testing multiple flags in many cases
+        */
+
+       unsigned long   flags;
+#define        Faulty          1               /* device is known to have a fault */
+#define        In_sync         2               /* device is in_sync with rest of array */
+#define        WriteMostly     4               /* Avoid reading if at all possible */
+#define        BarriersNotsupp 5               /* BIO_RW_BARRIER is not supported */
+#define        AllReserved     6               /* If whole device is reserved for
+                                        * one array */
+#define        AutoDetected    7               /* added by auto-detect */
+#define Blocked                8               /* An error occured on an externally
+                                        * managed array, don't allow writes
+                                        * until it is cleared */
+#define StateChanged   9               /* Faulty or Blocked has changed during
+                                        * interrupt, so it needs to be
+                                        * notified by the thread */
+       wait_queue_head_t blocked_wait;
+
+       int desc_nr;                    /* descriptor index in the superblock */
+       int raid_disk;                  /* role of device in array */
+       int saved_raid_disk;            /* role that device used to have in the
+                                        * array and could again if we did a partial
+                                        * resync from the bitmap
+                                        */
+       sector_t        recovery_offset;/* If this device has been partially
+                                        * recovered, this is where we were
+                                        * up to.
+                                        */
+
+       atomic_t        nr_pending;     /* number of pending requests.
+                                        * only maintained for arrays that
+                                        * support hot removal
+                                        */
+       atomic_t        read_errors;    /* number of consecutive read errors that
+                                        * we have tried to ignore.
+                                        */
+       atomic_t        corrected_errors; /* number of corrected read errors,
+                                          * for reporting to userspace and storing
+                                          * in superblock.
+                                          */
+       struct work_struct del_work;    /* used for delayed sysfs removal */
+
+       struct sysfs_dirent *sysfs_state; /* handle for 'state'
+                                          * sysfs entry */
+};
+
+struct mddev_s
+{
+       void                            *private;
+       struct mdk_personality          *pers;
+       dev_t                           unit;
+       int                             md_minor;
+       struct list_head                disks;
+       unsigned long                   flags;
+#define MD_CHANGE_DEVS 0       /* Some device status has changed */
+#define MD_CHANGE_CLEAN 1      /* transition to or from 'clean' */
+#define MD_CHANGE_PENDING 2    /* superblock update in progress */
+
+       int                             suspended;
+       atomic_t                        active_io;
+       int                             ro;
+
+       struct gendisk                  *gendisk;
+
+       struct kobject                  kobj;
+       int                             hold_active;
+#define        UNTIL_IOCTL     1
+#define        UNTIL_STOP      2
+
+       /* Superblock information */
+       int                             major_version,
+                                       minor_version,
+                                       patch_version;
+       int                             persistent;
+       int                             external;       /* metadata is
+                                                        * managed externally */
+       char                            metadata_type[17]; /* externally set*/
+       int                             chunk_size;
+       time_t                          ctime, utime;
+       int                             level, layout;
+       char                            clevel[16];
+       int                             raid_disks;
+       int                             max_disks;
+       sector_t                        dev_sectors;    /* used size of
+                                                        * component devices */
+       sector_t                        array_sectors; /* exported array size */
+       int                             external_size; /* size managed
+                                                       * externally */
+       __u64                           events;
+
+       char                            uuid[16];
+
+       /* If the array is being reshaped, we need to record the
+        * new shape and an indication of where we are up to.
+        * This is written to the superblock.
+        * If reshape_position is MaxSector, then no reshape is happening (yet).
+        */
+       sector_t                        reshape_position;
+       int                             delta_disks, new_level, new_layout, new_chunk;
+
+       struct mdk_thread_s             *thread;        /* management thread */
+       struct mdk_thread_s             *sync_thread;   /* doing resync or reconstruct */
+       sector_t                        curr_resync;    /* last block scheduled */
+       /* As resync requests can complete out of order, we cannot easily track
+        * how much resync has been completed.  So we occasionally pause until
+        * everything completes, then set curr_resync_completed to curr_resync.
+        * As such it may be well behind the real resync mark, but it is a value
+        * we are certain of.
+        */
+       sector_t                        curr_resync_completed;
+       unsigned long                   resync_mark;    /* a recent timestamp */
+       sector_t                        resync_mark_cnt;/* blocks written at resync_mark */
+       sector_t                        curr_mark_cnt; /* blocks scheduled now */
+
+       sector_t                        resync_max_sectors; /* may be set by personality */
+
+       sector_t                        resync_mismatches; /* count of sectors where
+                                                           * parity/replica mismatch found
+                                                           */
+
+       /* allow user-space to request suspension of IO to regions of the array */
+       sector_t                        suspend_lo;
+       sector_t                        suspend_hi;
+       /* if zero, use the system-wide default */
+       int                             sync_speed_min;
+       int                             sync_speed_max;
+
+       /* resync even though the same disks are shared among md-devices */
+       int                             parallel_resync;
+
+       int                             ok_start_degraded;
+       /* recovery/resync flags 
+        * NEEDED:   we might need to start a resync/recover
+        * RUNNING:  a thread is running, or about to be started
+        * SYNC:     actually doing a resync, not a recovery
+        * RECOVER:  doing recovery, or need to try it.
+        * INTR:     resync needs to be aborted for some reason
+        * DONE:     thread is done and is waiting to be reaped
+        * REQUEST:  user-space has requested a sync (used with SYNC)
+        * CHECK:    user-space request for for check-only, no repair
+        * RESHAPE:  A reshape is happening
+        *
+        * If neither SYNC or RESHAPE are set, then it is a recovery.
+        */
+#define        MD_RECOVERY_RUNNING     0
+#define        MD_RECOVERY_SYNC        1
+#define        MD_RECOVERY_RECOVER     2
+#define        MD_RECOVERY_INTR        3
+#define        MD_RECOVERY_DONE        4
+#define        MD_RECOVERY_NEEDED      5
+#define        MD_RECOVERY_REQUESTED   6
+#define        MD_RECOVERY_CHECK       7
+#define MD_RECOVERY_RESHAPE    8
+#define        MD_RECOVERY_FROZEN      9
+
+       unsigned long                   recovery;
+       int                             recovery_disabled; /* if we detect that recovery
+                                                           * will always fail, set this
+                                                           * so we don't loop trying */
+
+       int                             in_sync;        /* know to not need resync */
+       struct mutex                    reconfig_mutex;
+       atomic_t                        active;         /* general refcount */
+       atomic_t                        openers;        /* number of active opens */
+
+       int                             changed;        /* true if we might need to reread partition info */
+       int                             degraded;       /* whether md should consider
+                                                        * adding a spare
+                                                        */
+       int                             barriers_work;  /* initialised to true, cleared as soon
+                                                        * as a barrier request to slave
+                                                        * fails.  Only supported
+                                                        */
+       struct bio                      *biolist;       /* bios that need to be retried
+                                                        * because BIO_RW_BARRIER is not supported
+                                                        */
+
+       atomic_t                        recovery_active; /* blocks scheduled, but not written */
+       wait_queue_head_t               recovery_wait;
+       sector_t                        recovery_cp;
+       sector_t                        resync_min;     /* user requested sync
+                                                        * starts here */
+       sector_t                        resync_max;     /* resync should pause
+                                                        * when it gets here */
+
+       struct sysfs_dirent             *sysfs_state;   /* handle for 'array_state'
+                                                        * file in sysfs.
+                                                        */
+       struct sysfs_dirent             *sysfs_action;  /* handle for 'sync_action' */
+
+       struct work_struct del_work;    /* used for delayed sysfs removal */
+
+       spinlock_t                      write_lock;
+       wait_queue_head_t               sb_wait;        /* for waiting on superblock updates */
+       atomic_t                        pending_writes; /* number of active superblock writes */
+
+       unsigned int                    safemode;       /* if set, update "clean" superblock
+                                                        * when no writes pending.
+                                                        */ 
+       unsigned int                    safemode_delay;
+       struct timer_list               safemode_timer;
+       atomic_t                        writes_pending; 
+       struct request_queue            *queue; /* for plugging ... */
+
+       atomic_t                        write_behind; /* outstanding async IO */
+       unsigned int                    max_write_behind; /* 0 = sync */
+
+       struct bitmap                   *bitmap; /* the bitmap for the device */
+       struct file                     *bitmap_file; /* the bitmap file */
+       long                            bitmap_offset; /* offset from superblock of
+                                                       * start of bitmap. May be
+                                                       * negative, but not '0'
+                                                       */
+       long                            default_bitmap_offset; /* this is the offset to use when
+                                                               * hot-adding a bitmap.  It should
+                                                               * eventually be settable by sysfs.
+                                                               */
+
+       struct list_head                all_mddevs;
+};
+
+
+static inline void rdev_dec_pending(mdk_rdev_t *rdev, mddev_t *mddev)
+{
+       int faulty = test_bit(Faulty, &rdev->flags);
+       if (atomic_dec_and_test(&rdev->nr_pending) && faulty)
+               set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
+}
+
+static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
+{
+        atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
+}
+
+struct mdk_personality
+{
+       char *name;
+       int level;
+       struct list_head list;
+       struct module *owner;
+       int (*make_request)(struct request_queue *q, struct bio *bio);
+       int (*run)(mddev_t *mddev);
+       int (*stop)(mddev_t *mddev);
+       void (*status)(struct seq_file *seq, mddev_t *mddev);
+       /* error_handler must set ->faulty and clear ->in_sync
+        * if appropriate, and should abort recovery if needed 
+        */
+       void (*error_handler)(mddev_t *mddev, mdk_rdev_t *rdev);
+       int (*hot_add_disk) (mddev_t *mddev, mdk_rdev_t *rdev);
+       int (*hot_remove_disk) (mddev_t *mddev, int number);
+       int (*spare_active) (mddev_t *mddev);
+       sector_t (*sync_request)(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster);
+       int (*resize) (mddev_t *mddev, sector_t sectors);
+       sector_t (*size) (mddev_t *mddev, sector_t sectors, int raid_disks);
+       int (*check_reshape) (mddev_t *mddev);
+       int (*start_reshape) (mddev_t *mddev);
+       void (*finish_reshape) (mddev_t *mddev);
+       int (*reconfig) (mddev_t *mddev, int layout, int chunk_size);
+       /* quiesce moves between quiescence states
+        * 0 - fully active
+        * 1 - no new requests allowed
+        * others - reserved
+        */
+       void (*quiesce) (mddev_t *mddev, int state);
+       /* takeover is used to transition an array from one
+        * personality to another.  The new personality must be able
+        * to handle the data in the current layout.
+        * e.g. 2drive raid1 -> 2drive raid5
+        *      ndrive raid5 -> degraded n+1drive raid6 with special layout
+        * If the takeover succeeds, a new 'private' structure is returned.
+        * This needs to be installed and then ->run used to activate the
+        * array.
+        */
+       void *(*takeover) (mddev_t *mddev);
+};
+
+
+struct md_sysfs_entry {
+       struct attribute attr;
+       ssize_t (*show)(mddev_t *, char *);
+       ssize_t (*store)(mddev_t *, const char *, size_t);
+};
+
+
+static inline char * mdname (mddev_t * mddev)
+{
+       return mddev->gendisk ? mddev->gendisk->disk_name : "mdX";
+}
+
+/*
+ * iterates through some rdev ringlist. It's safe to remove the
+ * current 'rdev'. Dont touch 'tmp' though.
+ */
+#define rdev_for_each_list(rdev, tmp, head)                            \
+       list_for_each_entry_safe(rdev, tmp, head, same_set)
+
+/*
+ * iterates through the 'same array disks' ringlist
+ */
+#define rdev_for_each(rdev, tmp, mddev)                                \
+       list_for_each_entry_safe(rdev, tmp, &((mddev)->disks), same_set)
+
+#define rdev_for_each_rcu(rdev, mddev)                         \
+       list_for_each_entry_rcu(rdev, &((mddev)->disks), same_set)
+
+typedef struct mdk_thread_s {
+       void                    (*run) (mddev_t *mddev);
+       mddev_t                 *mddev;
+       wait_queue_head_t       wqueue;
+       unsigned long           flags;
+       struct task_struct      *tsk;
+       unsigned long           timeout;
+} mdk_thread_t;
+
+#define THREAD_WAKEUP  0
+
+#define __wait_event_lock_irq(wq, condition, lock, cmd)                \
+do {                                                                   \
+       wait_queue_t __wait;                                            \
+       init_waitqueue_entry(&__wait, current);                         \
+                                                                       \
+       add_wait_queue(&wq, &__wait);                                   \
+       for (;;) {                                                      \
+               set_current_state(TASK_UNINTERRUPTIBLE);                \
+               if (condition)                                          \
+                       break;                                          \
+               spin_unlock_irq(&lock);                                 \
+               cmd;                                                    \
+               schedule();                                             \
+               spin_lock_irq(&lock);                                   \
+       }                                                               \
+       current->state = TASK_RUNNING;                                  \
+       remove_wait_queue(&wq, &__wait);                                \
+} while (0)
+
+#define wait_event_lock_irq(wq, condition, lock, cmd)                  \
+do {                                                                   \
+       if (condition)                                                  \
+               break;                                                  \
+       __wait_event_lock_irq(wq, condition, lock, cmd);                \
+} while (0)
+
+static inline void safe_put_page(struct page *p)
+{
+       if (p) put_page(p);
+}
+
+#endif /* CONFIG_BLOCK */
+#endif
+
+
+extern int register_md_personality(struct mdk_personality *p);
+extern int unregister_md_personality(struct mdk_personality *p);
+extern mdk_thread_t * md_register_thread(void (*run) (mddev_t *mddev),
+                               mddev_t *mddev, const char *name);
+extern void md_unregister_thread(mdk_thread_t *thread);
+extern void md_wakeup_thread(mdk_thread_t *thread);
+extern void md_check_recovery(mddev_t *mddev);
+extern void md_write_start(mddev_t *mddev, struct bio *bi);
+extern void md_write_end(mddev_t *mddev);
+extern void md_done_sync(mddev_t *mddev, int blocks, int ok);
+extern void md_error(mddev_t *mddev, mdk_rdev_t *rdev);
+
+extern void md_super_write(mddev_t *mddev, mdk_rdev_t *rdev,
+                          sector_t sector, int size, struct page *page);
+extern void md_super_wait(mddev_t *mddev);
+extern int sync_page_io(struct block_device *bdev, sector_t sector, int size,
+                       struct page *page, int rw);
+extern void md_do_sync(mddev_t *mddev);
+extern void md_new_event(mddev_t *mddev);
+extern int md_allow_write(mddev_t *mddev);
+extern void md_wait_for_blocked_rdev(mdk_rdev_t *rdev, mddev_t *mddev);
+extern void md_set_array_sectors(mddev_t *mddev, sector_t array_sectors);