a6ff7e089c
Allow the metadata to be on a separate device from the data. This doesn't mean the data and metadata will by on separate physical devices - it simply gives device-mapper and userspace tools more flexibility. Signed-off-by: NeilBrown <neilb@suse.de>
533 lines
17 KiB
C
533 lines
17 KiB
C
/*
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md_k.h : kernel internal structure of the Linux MD driver
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Copyright (C) 1996-98 Ingo Molnar, Gadi Oxman
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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You should have received a copy of the GNU General Public License
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(for example /usr/src/linux/COPYING); if not, write to the Free
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Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#ifndef _MD_MD_H
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#define _MD_MD_H
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#include <linux/blkdev.h>
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#include <linux/kobject.h>
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#include <linux/list.h>
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#include <linux/mm.h>
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#include <linux/mutex.h>
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#include <linux/timer.h>
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#include <linux/wait.h>
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#include <linux/workqueue.h>
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#define MaxSector (~(sector_t)0)
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typedef struct mddev_s mddev_t;
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typedef struct mdk_rdev_s mdk_rdev_t;
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/* generic plugging support - like that provided with request_queue,
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* but does not require a request_queue
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*/
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struct plug_handle {
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void (*unplug_fn)(struct plug_handle *);
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struct timer_list unplug_timer;
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struct work_struct unplug_work;
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unsigned long unplug_flag;
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};
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#define PLUGGED_FLAG 1
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void plugger_init(struct plug_handle *plug,
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void (*unplug_fn)(struct plug_handle *));
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void plugger_set_plug(struct plug_handle *plug);
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int plugger_remove_plug(struct plug_handle *plug);
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static inline void plugger_flush(struct plug_handle *plug)
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{
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del_timer_sync(&plug->unplug_timer);
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cancel_work_sync(&plug->unplug_work);
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}
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/*
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* MD's 'extended' device
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*/
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struct mdk_rdev_s
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{
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struct list_head same_set; /* RAID devices within the same set */
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sector_t sectors; /* Device size (in 512bytes sectors) */
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mddev_t *mddev; /* RAID array if running */
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int last_events; /* IO event timestamp */
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/*
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* If meta_bdev is non-NULL, it means that a separate device is
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* being used to store the metadata (superblock/bitmap) which
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* would otherwise be contained on the same device as the data (bdev).
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*/
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struct block_device *meta_bdev;
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struct block_device *bdev; /* block device handle */
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struct page *sb_page;
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int sb_loaded;
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__u64 sb_events;
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sector_t data_offset; /* start of data in array */
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sector_t sb_start; /* offset of the super block (in 512byte sectors) */
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int sb_size; /* bytes in the superblock */
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int preferred_minor; /* autorun support */
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struct kobject kobj;
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/* A device can be in one of three states based on two flags:
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* Not working: faulty==1 in_sync==0
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* Fully working: faulty==0 in_sync==1
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* Working, but not
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* in sync with array
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* faulty==0 in_sync==0
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*
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* It can never have faulty==1, in_sync==1
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* This reduces the burden of testing multiple flags in many cases
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*/
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unsigned long flags;
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#define Faulty 1 /* device is known to have a fault */
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#define In_sync 2 /* device is in_sync with rest of array */
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#define WriteMostly 4 /* Avoid reading if at all possible */
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#define AllReserved 6 /* If whole device is reserved for
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* one array */
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#define AutoDetected 7 /* added by auto-detect */
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#define Blocked 8 /* An error occured on an externally
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* managed array, don't allow writes
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* until it is cleared */
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wait_queue_head_t blocked_wait;
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int desc_nr; /* descriptor index in the superblock */
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int raid_disk; /* role of device in array */
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int new_raid_disk; /* role that the device will have in
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* the array after a level-change completes.
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*/
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int saved_raid_disk; /* role that device used to have in the
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* array and could again if we did a partial
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* resync from the bitmap
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*/
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sector_t recovery_offset;/* If this device has been partially
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* recovered, this is where we were
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* up to.
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*/
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atomic_t nr_pending; /* number of pending requests.
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* only maintained for arrays that
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* support hot removal
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*/
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atomic_t read_errors; /* number of consecutive read errors that
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* we have tried to ignore.
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*/
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struct timespec last_read_error; /* monotonic time since our
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* last read error
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*/
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atomic_t corrected_errors; /* number of corrected read errors,
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* for reporting to userspace and storing
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* in superblock.
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*/
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struct work_struct del_work; /* used for delayed sysfs removal */
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struct sysfs_dirent *sysfs_state; /* handle for 'state'
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* sysfs entry */
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};
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struct mddev_s
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{
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void *private;
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struct mdk_personality *pers;
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dev_t unit;
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int md_minor;
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struct list_head disks;
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unsigned long flags;
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#define MD_CHANGE_DEVS 0 /* Some device status has changed */
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#define MD_CHANGE_CLEAN 1 /* transition to or from 'clean' */
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#define MD_CHANGE_PENDING 2 /* switch from 'clean' to 'active' in progress */
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int suspended;
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atomic_t active_io;
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int ro;
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int sysfs_active; /* set when sysfs deletes
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* are happening, so run/
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* takeover/stop are not safe
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*/
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int ready; /* See when safe to pass
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* IO requests down */
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struct gendisk *gendisk;
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struct kobject kobj;
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int hold_active;
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#define UNTIL_IOCTL 1
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#define UNTIL_STOP 2
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/* Superblock information */
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int major_version,
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minor_version,
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patch_version;
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int persistent;
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int external; /* metadata is
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* managed externally */
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char metadata_type[17]; /* externally set*/
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int chunk_sectors;
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time_t ctime, utime;
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int level, layout;
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char clevel[16];
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int raid_disks;
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int max_disks;
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sector_t dev_sectors; /* used size of
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* component devices */
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sector_t array_sectors; /* exported array size */
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int external_size; /* size managed
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* externally */
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__u64 events;
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/* If the last 'event' was simply a clean->dirty transition, and
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* we didn't write it to the spares, then it is safe and simple
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* to just decrement the event count on a dirty->clean transition.
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* So we record that possibility here.
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*/
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int can_decrease_events;
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char uuid[16];
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/* If the array is being reshaped, we need to record the
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* new shape and an indication of where we are up to.
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* This is written to the superblock.
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* If reshape_position is MaxSector, then no reshape is happening (yet).
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*/
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sector_t reshape_position;
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int delta_disks, new_level, new_layout;
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int new_chunk_sectors;
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struct mdk_thread_s *thread; /* management thread */
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struct mdk_thread_s *sync_thread; /* doing resync or reconstruct */
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sector_t curr_resync; /* last block scheduled */
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/* As resync requests can complete out of order, we cannot easily track
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* how much resync has been completed. So we occasionally pause until
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* everything completes, then set curr_resync_completed to curr_resync.
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* As such it may be well behind the real resync mark, but it is a value
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* we are certain of.
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*/
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sector_t curr_resync_completed;
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unsigned long resync_mark; /* a recent timestamp */
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sector_t resync_mark_cnt;/* blocks written at resync_mark */
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sector_t curr_mark_cnt; /* blocks scheduled now */
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sector_t resync_max_sectors; /* may be set by personality */
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sector_t resync_mismatches; /* count of sectors where
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* parity/replica mismatch found
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*/
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/* allow user-space to request suspension of IO to regions of the array */
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sector_t suspend_lo;
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sector_t suspend_hi;
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/* if zero, use the system-wide default */
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int sync_speed_min;
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int sync_speed_max;
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/* resync even though the same disks are shared among md-devices */
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int parallel_resync;
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int ok_start_degraded;
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/* recovery/resync flags
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* NEEDED: we might need to start a resync/recover
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* RUNNING: a thread is running, or about to be started
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* SYNC: actually doing a resync, not a recovery
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* RECOVER: doing recovery, or need to try it.
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* INTR: resync needs to be aborted for some reason
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* DONE: thread is done and is waiting to be reaped
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* REQUEST: user-space has requested a sync (used with SYNC)
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* CHECK: user-space request for check-only, no repair
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* RESHAPE: A reshape is happening
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*
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* If neither SYNC or RESHAPE are set, then it is a recovery.
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*/
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#define MD_RECOVERY_RUNNING 0
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#define MD_RECOVERY_SYNC 1
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#define MD_RECOVERY_RECOVER 2
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#define MD_RECOVERY_INTR 3
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#define MD_RECOVERY_DONE 4
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#define MD_RECOVERY_NEEDED 5
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#define MD_RECOVERY_REQUESTED 6
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#define MD_RECOVERY_CHECK 7
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#define MD_RECOVERY_RESHAPE 8
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#define MD_RECOVERY_FROZEN 9
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unsigned long recovery;
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int recovery_disabled; /* if we detect that recovery
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* will always fail, set this
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* so we don't loop trying */
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int in_sync; /* know to not need resync */
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/* 'open_mutex' avoids races between 'md_open' and 'do_md_stop', so
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* that we are never stopping an array while it is open.
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* 'reconfig_mutex' protects all other reconfiguration.
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* These locks are separate due to conflicting interactions
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* with bdev->bd_mutex.
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* Lock ordering is:
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* reconfig_mutex -> bd_mutex : e.g. do_md_run -> revalidate_disk
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* bd_mutex -> open_mutex: e.g. __blkdev_get -> md_open
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*/
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struct mutex open_mutex;
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struct mutex reconfig_mutex;
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atomic_t active; /* general refcount */
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atomic_t openers; /* number of active opens */
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int degraded; /* whether md should consider
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* adding a spare
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*/
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atomic_t recovery_active; /* blocks scheduled, but not written */
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wait_queue_head_t recovery_wait;
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sector_t recovery_cp;
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sector_t resync_min; /* user requested sync
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* starts here */
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sector_t resync_max; /* resync should pause
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* when it gets here */
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struct sysfs_dirent *sysfs_state; /* handle for 'array_state'
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* file in sysfs.
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*/
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struct sysfs_dirent *sysfs_action; /* handle for 'sync_action' */
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struct work_struct del_work; /* used for delayed sysfs removal */
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spinlock_t write_lock;
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wait_queue_head_t sb_wait; /* for waiting on superblock updates */
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atomic_t pending_writes; /* number of active superblock writes */
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unsigned int safemode; /* if set, update "clean" superblock
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* when no writes pending.
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*/
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unsigned int safemode_delay;
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struct timer_list safemode_timer;
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atomic_t writes_pending;
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struct request_queue *queue; /* for plugging ... */
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struct bitmap *bitmap; /* the bitmap for the device */
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struct {
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struct file *file; /* the bitmap file */
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loff_t offset; /* offset from superblock of
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* start of bitmap. May be
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* negative, but not '0'
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* For external metadata, offset
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* from start of device.
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*/
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loff_t default_offset; /* this is the offset to use when
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* hot-adding a bitmap. It should
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* eventually be settable by sysfs.
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*/
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/* When md is serving under dm, it might use a
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* dirty_log to store the bits.
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*/
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struct dm_dirty_log *log;
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struct mutex mutex;
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unsigned long chunksize;
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unsigned long daemon_sleep; /* how many jiffies between updates? */
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unsigned long max_write_behind; /* write-behind mode */
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int external;
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} bitmap_info;
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atomic_t max_corr_read_errors; /* max read retries */
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struct list_head all_mddevs;
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struct attribute_group *to_remove;
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struct plug_handle *plug; /* if used by personality */
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struct bio_set *bio_set;
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/* Generic flush handling.
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* The last to finish preflush schedules a worker to submit
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* the rest of the request (without the REQ_FLUSH flag).
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*/
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struct bio *flush_bio;
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atomic_t flush_pending;
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struct work_struct flush_work;
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struct work_struct event_work; /* used by dm to report failure event */
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};
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static inline void rdev_dec_pending(mdk_rdev_t *rdev, mddev_t *mddev)
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{
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int faulty = test_bit(Faulty, &rdev->flags);
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if (atomic_dec_and_test(&rdev->nr_pending) && faulty)
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set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
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}
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static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
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{
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atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
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}
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struct mdk_personality
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{
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char *name;
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int level;
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struct list_head list;
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struct module *owner;
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int (*make_request)(mddev_t *mddev, struct bio *bio);
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int (*run)(mddev_t *mddev);
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int (*stop)(mddev_t *mddev);
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void (*status)(struct seq_file *seq, mddev_t *mddev);
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/* error_handler must set ->faulty and clear ->in_sync
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* if appropriate, and should abort recovery if needed
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*/
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void (*error_handler)(mddev_t *mddev, mdk_rdev_t *rdev);
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int (*hot_add_disk) (mddev_t *mddev, mdk_rdev_t *rdev);
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int (*hot_remove_disk) (mddev_t *mddev, int number);
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int (*spare_active) (mddev_t *mddev);
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sector_t (*sync_request)(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster);
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int (*resize) (mddev_t *mddev, sector_t sectors);
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sector_t (*size) (mddev_t *mddev, sector_t sectors, int raid_disks);
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int (*check_reshape) (mddev_t *mddev);
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int (*start_reshape) (mddev_t *mddev);
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void (*finish_reshape) (mddev_t *mddev);
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/* quiesce moves between quiescence states
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* 0 - fully active
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* 1 - no new requests allowed
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* others - reserved
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*/
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void (*quiesce) (mddev_t *mddev, int state);
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/* takeover is used to transition an array from one
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* personality to another. The new personality must be able
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* to handle the data in the current layout.
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* e.g. 2drive raid1 -> 2drive raid5
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* ndrive raid5 -> degraded n+1drive raid6 with special layout
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* If the takeover succeeds, a new 'private' structure is returned.
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* This needs to be installed and then ->run used to activate the
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* array.
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*/
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void *(*takeover) (mddev_t *mddev);
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};
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struct md_sysfs_entry {
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struct attribute attr;
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ssize_t (*show)(mddev_t *, char *);
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ssize_t (*store)(mddev_t *, const char *, size_t);
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};
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extern struct attribute_group md_bitmap_group;
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static inline struct sysfs_dirent *sysfs_get_dirent_safe(struct sysfs_dirent *sd, char *name)
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{
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if (sd)
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return sysfs_get_dirent(sd, NULL, name);
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return sd;
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}
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static inline void sysfs_notify_dirent_safe(struct sysfs_dirent *sd)
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{
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if (sd)
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sysfs_notify_dirent(sd);
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}
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static inline char * mdname (mddev_t * mddev)
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{
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return mddev->gendisk ? mddev->gendisk->disk_name : "mdX";
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}
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/*
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* iterates through some rdev ringlist. It's safe to remove the
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* current 'rdev'. Dont touch 'tmp' though.
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*/
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#define rdev_for_each_list(rdev, tmp, head) \
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list_for_each_entry_safe(rdev, tmp, head, same_set)
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/*
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* iterates through the 'same array disks' ringlist
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*/
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#define rdev_for_each(rdev, tmp, mddev) \
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list_for_each_entry_safe(rdev, tmp, &((mddev)->disks), same_set)
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#define rdev_for_each_rcu(rdev, mddev) \
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list_for_each_entry_rcu(rdev, &((mddev)->disks), same_set)
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typedef struct mdk_thread_s {
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void (*run) (mddev_t *mddev);
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mddev_t *mddev;
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wait_queue_head_t wqueue;
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unsigned long flags;
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struct task_struct *tsk;
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unsigned long timeout;
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} mdk_thread_t;
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#define THREAD_WAKEUP 0
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#define __wait_event_lock_irq(wq, condition, lock, cmd) \
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do { \
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wait_queue_t __wait; \
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init_waitqueue_entry(&__wait, current); \
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\
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add_wait_queue(&wq, &__wait); \
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for (;;) { \
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set_current_state(TASK_UNINTERRUPTIBLE); \
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if (condition) \
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break; \
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spin_unlock_irq(&lock); \
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cmd; \
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schedule(); \
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spin_lock_irq(&lock); \
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} \
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current->state = TASK_RUNNING; \
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remove_wait_queue(&wq, &__wait); \
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} while (0)
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#define wait_event_lock_irq(wq, condition, lock, cmd) \
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do { \
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if (condition) \
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break; \
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__wait_event_lock_irq(wq, condition, lock, cmd); \
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} while (0)
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static inline void safe_put_page(struct page *p)
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{
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if (p) put_page(p);
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}
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extern int register_md_personality(struct mdk_personality *p);
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extern int unregister_md_personality(struct mdk_personality *p);
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extern mdk_thread_t * md_register_thread(void (*run) (mddev_t *mddev),
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mddev_t *mddev, const char *name);
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extern void md_unregister_thread(mdk_thread_t *thread);
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extern void md_wakeup_thread(mdk_thread_t *thread);
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extern void md_check_recovery(mddev_t *mddev);
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extern void md_write_start(mddev_t *mddev, struct bio *bi);
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extern void md_write_end(mddev_t *mddev);
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extern void md_done_sync(mddev_t *mddev, int blocks, int ok);
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extern void md_error(mddev_t *mddev, mdk_rdev_t *rdev);
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extern int mddev_congested(mddev_t *mddev, int bits);
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extern void md_flush_request(mddev_t *mddev, struct bio *bio);
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extern void md_super_write(mddev_t *mddev, mdk_rdev_t *rdev,
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sector_t sector, int size, struct page *page);
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extern void md_super_wait(mddev_t *mddev);
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extern int sync_page_io(mdk_rdev_t *rdev, sector_t sector, int size,
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struct page *page, int rw, bool metadata_op);
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extern void md_do_sync(mddev_t *mddev);
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extern void md_new_event(mddev_t *mddev);
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extern int md_allow_write(mddev_t *mddev);
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extern void md_wait_for_blocked_rdev(mdk_rdev_t *rdev, mddev_t *mddev);
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extern void md_set_array_sectors(mddev_t *mddev, sector_t array_sectors);
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extern int md_check_no_bitmap(mddev_t *mddev);
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extern int md_integrity_register(mddev_t *mddev);
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extern void md_integrity_add_rdev(mdk_rdev_t *rdev, mddev_t *mddev);
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extern int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale);
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extern void restore_bitmap_write_access(struct file *file);
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extern void md_unplug(mddev_t *mddev);
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extern void mddev_init(mddev_t *mddev);
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extern int md_run(mddev_t *mddev);
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extern void md_stop(mddev_t *mddev);
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extern void md_stop_writes(mddev_t *mddev);
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extern void md_rdev_init(mdk_rdev_t *rdev);
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extern void mddev_suspend(mddev_t *mddev);
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extern void mddev_resume(mddev_t *mddev);
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extern struct bio *bio_clone_mddev(struct bio *bio, gfp_t gfp_mask,
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mddev_t *mddev);
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extern struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs,
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mddev_t *mddev);
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#endif /* _MD_MD_H */
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