/* 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 #include #include #include #include #include #include #include #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 new_data_offset;/* only relevant while reshaping */ 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 kernfs_node *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 */ Bitmap_sync, /* ..actually, not quite In_sync. Need a * bitmap-based recovery to get fully in sync */ 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 is_new); extern int rdev_clear_badblocks(struct md_rdev *rdev, sector_t s, int sectors, int is_new); 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_UPDATE_SB_FLAGS (1 | 2 | 4) /* If these are set, md_update_sb needed */ #define MD_ARRAY_FIRST_USE 3 /* First use of array, needs initialization */ #define MD_STILL_CLOSED 4 /* If set, then array has not been opened since * md_ioctl checked on it. */ 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; int reshape_backwards; struct md_thread *thread; /* management thread */ struct md_thread *sync_thread; /* doing resync or reconstruct */ /* 'last_sync_action' is initialized to "none". It is set when a * sync operation (i.e "data-check", "requested-resync", "resync", * "recovery", or "reshape") is started. It holds this value even * when the sync thread is "frozen" (interrupted) or "idle" (stopped * or finished). It is overwritten when a new sync operation is begun. */ char *last_sync_action; 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 */ atomic64_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 * ERROR: sync-action interrupted because io-error * * 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 #define MD_RECOVERY_ERROR 10 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 kernfs_node *sysfs_state; /* handle for 'array_state' * file in sysfs. */ struct kernfs_node *sysfs_action; /* handle for 'sync_action' */ struct work_struct del_work; /* used for delayed sysfs removal */ /* "lock" protects: * flush_bio transition from NULL to !NULL * rdev superblocks, events * clearing MD_CHANGE_* * in_sync - and related safemode and MD_CHANGE changes * pers (also protected by reconfig_mutex and pending IO). * clearing ->bitmap * clearing ->bitmap_info.file * changing ->resync_{min,max} * setting MD_RECOVERY_RUNNING (which interacts with resync_{min,max}) */ spinlock_t 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. */ unsigned long space; /* space available at this offset */ loff_t default_offset; /* this is the offset to use when * hot-adding a bitmap. It should * eventually be settable by sysfs. */ unsigned long default_space; /* space available at * default offset */ 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); void (*free)(struct mddev *mddev, void *priv); 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); /* congested implements bdi.congested_fn(). * Will not be called while array is 'suspended' */ int (*congested)(struct mddev *mddev, int bits); /* mergeable_bvec is use to implement ->merge_bvec_fn */ int (*mergeable_bvec)(struct mddev *mddev, struct bvec_merge_data *bvm, struct bio_vec *biovec); }; 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 kernfs_node *sysfs_get_dirent_safe(struct kernfs_node *sd, char *name) { if (sd) return sysfs_get_dirent(sd, name); return sd; } static inline void sysfs_notify_dirent_safe(struct kernfs_node *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) && mddev->kobj.sd) { 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) && mddev->kobj.sd) { 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 md_thread *thread); struct mddev *mddev; wait_queue_head_t wqueue; unsigned long flags; struct task_struct *tsk; unsigned long timeout; void *private; }; #define THREAD_WAKEUP 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 md_thread *thread), 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_reap_sync_thread(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 void md_finish_reshape(struct mddev *mddev); 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 md_thread *thread); 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 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 md_rdev_clear(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 void md_unplug(struct blk_plug_cb *cb, bool from_schedule); static inline int mddev_check_plugged(struct mddev *mddev) { return !!blk_check_plugged(md_unplug, mddev, sizeof(struct blk_plug_cb)); } #endif /* _MD_MD_H */