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|
/*
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/backing-dev.h>
#include <linux/badblocks.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>
#include "md-cluster.h"
#define MaxSector (~(sector_t)0)
/*
* These flags should really be called "NO_RETRY" rather than
* "FAILFAST" because they don't make any promise about time lapse,
* only about the number of retries, which will be zero.
* REQ_FAILFAST_DRIVER is not included because
* Commit: 4a27446f3e39 ("[SCSI] modify scsi to handle new fail fast flags.")
* seems to suggest that the errors it avoids retrying should usually
* be retried.
*/
#define MD_FAILFAST (REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT)
/*
* 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
*/
union {
sector_t recovery_offset;/* If this device has been partially
* recovered, this is where we were
* up to.
*/
sector_t journal_tail; /* If this device is a journal device,
* this is the journal tail (journal
* recovery start point)
*/
};
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.
*/
time64_t 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 badblocks;
struct {
short offset; /* Offset from superblock to start of PPL.
* Not used by external metadata. */
unsigned int size; /* Size in sectors of the PPL space */
sector_t sector; /* First sector of the PPL space */
} ppl;
};
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
*/
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.
*/
Candidate, /* For clustered environments only:
* This device is seen locally but not
* by the whole cluster
*/
Journal, /* This device is used as journal for
* raid-5/6.
* Usually, this device should be faster
* than other devices in the array
*/
ClusterRemove,
RemoveSynchronized, /* synchronize_rcu() was called after
* this device was known to be faulty,
* so it is safe to remove without
* another synchronize_rcu() call.
*/
ExternalBbl, /* External metadata provides bad
* block management for a disk
*/
FailFast, /* Minimal retries should be attempted on
* this device, so use REQ_FAILFAST_DEV.
* Also don't try to repair failed reads.
* It is expects that no bad block log
* is present.
*/
LastDev, /* Seems to be the last working dev as
* it didn't fail, so don't use FailFast
* any more for metadata
*/
};
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 = badblocks_check(&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);
struct md_cluster_info;
/* change UNSUPPORTED_MDDEV_FLAGS for each array type if new flag is added */
enum mddev_flags {
MD_ARRAY_FIRST_USE, /* First use of array, needs initialization */
MD_CLOSING, /* If set, we are closing the array, do not open
* it then */
MD_JOURNAL_CLEAN, /* A raid with journal is already clean */
MD_HAS_JOURNAL, /* The raid array has journal feature set */
MD_CLUSTER_RESYNC_LOCKED, /* cluster raid only, which means node
* already took resync lock, need to
* release the lock */
MD_FAILFAST_SUPPORTED, /* Using MD_FAILFAST on metadata writes is
* supported as calls to md_error() will
* never cause the array to become failed.
*/
MD_HAS_PPL, /* The raid array has PPL feature set */
};
enum mddev_sb_flags {
MD_SB_CHANGE_DEVS, /* Some device status has changed */
MD_SB_CHANGE_CLEAN, /* transition to or from 'clean' */
MD_SB_CHANGE_PENDING, /* switch from 'clean' to 'active' in progress */
MD_SB_NEED_REWRITE, /* metadata write needs to be repeated */
};
struct mddev {
void *private;
struct md_personality *pers;
dev_t unit;
int md_minor;
struct list_head disks;
unsigned long flags;
unsigned long sb_flags;
int suspended;
atomic_t active_io;
int ro;
int sysfs_active; /* set when sysfs deletes
* are happening, so run/
* takeover/stop are not safe
*/
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;
time64_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.
|