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Diffstat (limited to 'drivers/md/md.h')
| -rw-r--r-- | drivers/md/md.h | 627 |
1 files changed, 627 insertions, 0 deletions
diff --git a/drivers/md/md.h b/drivers/md/md.h new file mode 100644 index 00000000..1c2063cc --- /dev/null +++ b/drivers/md/md.h @@ -0,0 +1,627 @@ +/* + md.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) + +/* Bad block numbers are stored sorted in a single page. + * 64bits is used for each block or extent. + * 54 bits are sector number, 9 bits are extent size, + * 1 bit is an 'acknowledged' flag. + */ +#define MD_MAX_BADBLOCKS (PAGE_SIZE/8) + +/* + * MD's 'extended' device + */ +struct md_rdev { + struct list_head same_set; /* RAID devices within the same set */ + + sector_t sectors; /* Device size (in 512bytes sectors) */ + struct mddev *mddev; /* RAID array if running */ + int last_events; /* IO event timestamp */ + + /* + * If meta_bdev is non-NULL, it means that a separate device is + * being used to store the metadata (superblock/bitmap) which + * would otherwise be contained on the same device as the data (bdev). + */ + struct block_device *meta_bdev; + struct block_device *bdev; /* block device handle */ + + struct page *sb_page, *bb_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; /* bit set of 'enum flag_bits' bits. */ + wait_queue_head_t blocked_wait; + + int desc_nr; /* descriptor index in the superblock */ + int raid_disk; /* role of device in array */ + int new_raid_disk; /* role that the device will have in + * the array after a level-change completes. + */ + 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. + */ + struct timespec last_read_error; /* monotonic time since our + * last read error + */ + 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 badblocks { + int count; /* count of bad blocks */ + int unacked_exist; /* there probably are unacknowledged + * bad blocks. This is only cleared + * when a read discovers none + */ + int shift; /* shift from sectors to block size + * a -ve shift means badblocks are + * disabled.*/ + u64 *page; /* badblock list */ + int changed; + seqlock_t lock; + + sector_t sector; + sector_t size; /* in sectors */ + } badblocks; +}; +enum flag_bits { + Faulty, /* device is known to have a fault */ + In_sync, /* device is in_sync with rest of array */ + Unmerged, /* device is being added to array and should + * be considerred for bvec_merge_fn but not + * yet for actual IO + */ + WriteMostly, /* Avoid reading if at all possible */ + AutoDetected, /* added by auto-detect */ + Blocked, /* An error occurred but has not yet + * been acknowledged by the metadata + * handler, so don't allow writes + * until it is cleared */ + WriteErrorSeen, /* A write error has been seen on this + * device + */ + FaultRecorded, /* Intermediate state for clearing + * Blocked. The Fault is/will-be + * recorded in the metadata, but that + * metadata hasn't been stored safely + * on disk yet. + */ + BlockedBadBlocks, /* A writer is blocked because they + * found an unacknowledged bad-block. + * This can safely be cleared at any + * time, and the writer will re-check. + * It may be set at any time, and at + * worst the writer will timeout and + * re-check. So setting it as + * accurately as possible is good, but + * not absolutely critical. + */ + WantReplacement, /* This device is a candidate to be + * hot-replaced, either because it has + * reported some faults, or because + * of explicit request. + */ + Replacement, /* This device is a replacement for + * a want_replacement device with same + * raid_disk number. + */ +}; + +#define BB_LEN_MASK (0x00000000000001FFULL) +#define BB_OFFSET_MASK (0x7FFFFFFFFFFFFE00ULL) +#define BB_ACK_MASK (0x8000000000000000ULL) +#define BB_MAX_LEN 512 +#define BB_OFFSET(x) (((x) & BB_OFFSET_MASK) >> 9) +#define BB_LEN(x) (((x) & BB_LEN_MASK) + 1) +#define BB_ACK(x) (!!((x) & BB_ACK_MASK)) +#define BB_MAKE(a, l, ack) (((a)<<9) | ((l)-1) | ((u64)(!!(ack)) << 63)) + +extern int md_is_badblock(struct badblocks *bb, sector_t s, int sectors, + sector_t *first_bad, int *bad_sectors); +static inline int is_badblock(struct md_rdev *rdev, sector_t s, int sectors, + sector_t *first_bad, int *bad_sectors) +{ + if (unlikely(rdev->badblocks.count)) { + int rv = md_is_badblock(&rdev->badblocks, rdev->data_offset + s, + sectors, + first_bad, bad_sectors); + if (rv) + *first_bad -= rdev->data_offset; + return rv; + } + return 0; +} +extern int rdev_set_badblocks(struct md_rdev *rdev, sector_t s, int sectors, + int acknowledged); +extern int rdev_clear_badblocks(struct md_rdev *rdev, sector_t s, int sectors); +extern void md_ack_all_badblocks(struct badblocks *bb); + +struct mddev { + void *private; + struct md_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 /* switch from 'clean' to 'active' in progress */ +#define MD_ARRAY_FIRST_USE 3 /* First use of array, needs initialization */ + + int suspended; + atomic_t active_io; + int ro; + int sysfs_active; /* set when sysfs deletes + * are happening, so run/ + * takeover/stop are not safe + */ + int ready; /* See when safe to pass + * IO requests down */ + 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_sectors; + 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; + /* If the last 'event' was simply a clean->dirty transition, and + * we didn't write it to the spares, then it is safe and simple + * to just decrement the event count on a dirty->clean transition. + * So we record that possibility here. + */ + int can_decrease_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; + int new_chunk_sectors; + + atomic_t plug_cnt; /* If device is expecting + * more bios soon. + */ + struct md_thread *thread; /* management thread */ + struct md_thread *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 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; + /* If a RAID personality determines that recovery (of a particular + * device) will fail due to a read error on the source device, it + * takes a copy of this number and does not attempt recovery again + * until this number changes. + */ + int recovery_disabled; + + int in_sync; /* know to not need resync */ + /* 'open_mutex' avoids races between 'md_open' and 'do_md_stop', so + * that we are never stopping an array while it is open. + * 'reconfig_mutex' protects all other reconfiguration. + * These locks are separate due to conflicting interactions + * with bdev->bd_mutex. + * Lock ordering is: + * reconfig_mutex -> bd_mutex : e.g. do_md_run -> revalidate_disk + * bd_mutex -> open_mutex: e.g. __blkdev_get -> md_open + */ + struct mutex open_mutex; + 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 merge_check_needed; /* at least one + * member device + * has a + * merge_bvec_fn */ + + 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 ... */ + + struct bitmap *bitmap; /* the bitmap for the device */ + struct { + struct file *file; /* the bitmap file */ + loff_t offset; /* offset from superblock of + * start of bitmap. May be + * negative, but not '0' + * For external metadata, offset + * from start of device. + */ + loff_t default_offset; /* this is the offset to use when + * hot-adding a bitmap. It should + * eventually be settable by sysfs. + */ + struct mutex mutex; + unsigned long chunksize; + unsigned long daemon_sleep; /* how many jiffies between updates? */ + unsigned long max_write_behind; /* write-behind mode */ + int external; + } bitmap_info; + + atomic_t max_corr_read_errors; /* max read retries */ + struct list_head all_mddevs; + + struct attribute_group *to_remove; + + struct bio_set *bio_set; + + /* Generic flush handling. + * The last to finish preflush schedules a worker to submit + * the rest of the request (without the REQ_FLUSH flag). + */ + struct bio *flush_bio; + atomic_t flush_pending; + struct work_struct flush_work; + struct work_struct event_work; /* used by dm to report failure event */ + void (*sync_super)(struct mddev *mddev, struct md_rdev *rdev); +}; + + +static inline void rdev_dec_pending(struct md_rdev *rdev, struct mddev *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 md_personality +{ + char *name; + int level; + struct list_head list; + struct module *owner; + void (*make_request)(struct mddev *mddev, struct bio *bio); + int (*run)(struct mddev *mddev); + int (*stop)(struct mddev *mddev); + void (*status)(struct seq_file *seq, struct mddev *mddev); + /* error_handler must set ->faulty and clear ->in_sync + * if appropriate, and should abort recovery if needed + */ + void (*error_handler)(struct mddev *mddev, struct md_rdev *rdev); + int (*hot_add_disk) (struct mddev *mddev, struct md_rdev *rdev); + int (*hot_remove_disk) (struct mddev *mddev, struct md_rdev *rdev); + int (*spare_active) (struct mddev *mddev); + sector_t (*sync_request)(struct mddev *mddev, sector_t sector_nr, int *skipped, int go_faster); + int (*resize) (struct mddev *mddev, sector_t sectors); + sector_t (*size) (struct mddev *mddev, sector_t sectors, int raid_disks); + int (*check_reshape) (struct mddev *mddev); + int (*start_reshape) (struct mddev *mddev); + void (*finish_reshape) (struct mddev *mddev); + /* quiesce moves between quiescence states + * 0 - fully active + * 1 - no new requests allowed + * others - reserved + */ + void (*quiesce) (struct mddev *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) (struct mddev *mddev); +}; + + +struct md_sysfs_entry { + struct attribute attr; + ssize_t (*show)(struct mddev *, char *); + ssize_t (*store)(struct mddev *, const char *, size_t); +}; +extern struct attribute_group md_bitmap_group; + +static inline struct sysfs_dirent *sysfs_get_dirent_safe(struct sysfs_dirent *sd, char *name) +{ + if (sd) + return sysfs_get_dirent(sd, NULL, name); + return sd; +} +static inline void sysfs_notify_dirent_safe(struct sysfs_dirent *sd) +{ + if (sd) + sysfs_notify_dirent(sd); +} + +static inline char * mdname (struct mddev * mddev) +{ + return mddev->gendisk ? mddev->gendisk->disk_name : "mdX"; +} + +static inline int sysfs_link_rdev(struct mddev *mddev, struct md_rdev *rdev) +{ + char nm[20]; + if (!test_bit(Replacement, &rdev->flags)) { + sprintf(nm, "rd%d", rdev->raid_disk); + return sysfs_create_link(&mddev->kobj, &rdev->kobj, nm); + } else + return 0; +} + +static inline void sysfs_unlink_rdev(struct mddev *mddev, struct md_rdev *rdev) +{ + char nm[20]; + if (!test_bit(Replacement, &rdev->flags)) { + sprintf(nm, "rd%d", rdev->raid_disk); + sysfs_remove_link(&mddev->kobj, nm); + } +} + +/* + * 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, mddev) \ + list_for_each_entry(rdev, &((mddev)->disks), same_set) + +#define rdev_for_each_safe(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) + +struct md_thread { + void (*run) (struct mddev *mddev); + struct mddev *mddev; + wait_queue_head_t wqueue; + unsigned long flags; + struct task_struct *tsk; + unsigned long timeout; +}; + +#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 md_personality *p); +extern int unregister_md_personality(struct md_personality *p); +extern struct md_thread *md_register_thread( + void (*run)(struct mddev *mddev), + struct mddev *mddev, + const char *name); +extern void md_unregister_thread(struct md_thread **threadp); +extern void md_wakeup_thread(struct md_thread *thread); +extern void md_check_recovery(struct mddev *mddev); +extern void md_write_start(struct mddev *mddev, struct bio *bi); +extern void md_write_end(struct mddev *mddev); +extern void md_done_sync(struct mddev *mddev, int blocks, int ok); +extern void md_error(struct mddev *mddev, struct md_rdev *rdev); + +extern int mddev_congested(struct mddev *mddev, int bits); +extern void md_flush_request(struct mddev *mddev, struct bio *bio); +extern void md_super_write(struct mddev *mddev, struct md_rdev *rdev, + sector_t sector, int size, struct page *page); +extern void md_super_wait(struct mddev *mddev); +extern int sync_page_io(struct md_rdev *rdev, sector_t sector, int size, + struct page *page, int rw, bool metadata_op); +extern void md_do_sync(struct mddev *mddev); +extern void md_new_event(struct mddev *mddev); +extern int md_allow_write(struct mddev *mddev); +extern void md_wait_for_blocked_rdev(struct md_rdev *rdev, struct mddev *mddev); +extern void md_set_array_sectors(struct mddev *mddev, sector_t array_sectors); +extern int md_check_no_bitmap(struct mddev *mddev); +extern int md_integrity_register(struct mddev *mddev); +extern void md_integrity_add_rdev(struct md_rdev *rdev, struct mddev *mddev); +extern int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale); +extern void restore_bitmap_write_access(struct file *file); + +extern void mddev_init(struct mddev *mddev); +extern int md_run(struct mddev *mddev); +extern void md_stop(struct mddev *mddev); +extern void md_stop_writes(struct mddev *mddev); +extern int md_rdev_init(struct md_rdev *rdev); + +extern void mddev_suspend(struct mddev *mddev); +extern void mddev_resume(struct mddev *mddev); +extern struct bio *bio_clone_mddev(struct bio *bio, gfp_t gfp_mask, + struct mddev *mddev); +extern struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs, + struct mddev *mddev); +extern int mddev_check_plugged(struct mddev *mddev); +extern void md_trim_bio(struct bio *bio, int offset, int size); +#endif /* _MD_MD_H */ |