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Diffstat (limited to 'drivers/md/md.h')
| -rw-r--r-- | drivers/md/md.h | 441 |
1 files changed, 441 insertions, 0 deletions
diff --git a/drivers/md/md.h b/drivers/md/md.h new file mode 100644 index 000000000000..8227ab909d44 --- /dev/null +++ b/drivers/md/md.h @@ -0,0 +1,441 @@ +/* + 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_MD_H +#define _MD_MD_H + +#include <linux/blkdev.h> +#include <linux/kobject.h> +#include <linux/list.h> +#include <linux/mm.h> +#include <linux/mutex.h> +#include <linux/timer.h> +#include <linux/wait.h> +#include <linux/workqueue.h> + +#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); +} + +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); + +#endif /* _MD_MD_H */ |