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md.c
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/*
md.c : Multiple Devices driver for Linux
Copyright (C) 1998, 1999, 2000 Ingo Molnar
completely rewritten, based on the MD driver code from Marc Zyngier
Changes:
- RAID-1/RAID-5 extensions by Miguel de Icaza, Gadi Oxman, Ingo Molnar
- RAID-6 extensions by H. Peter Anvin <[email protected]>
- boot support for linear and striped mode by Harald Hoyer <[email protected]>
- kerneld support by Boris Tobotras <[email protected]>
- kmod support by: Cyrus Durgin
- RAID0 bugfixes: Mark Anthony Lisher <[email protected]>
- Devfs support by Richard Gooch <[email protected]>
- lots of fixes and improvements to the RAID1/RAID5 and generic
RAID code (such as request based resynchronization):
Neil Brown <[email protected]>.
- persistent bitmap code
Copyright (C) 2003-2004, Paul Clements, SteelEye Technology, Inc.
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.
Errors, Warnings, etc.
Please use:
pr_crit() for error conditions that risk data loss
pr_err() for error conditions that are unexpected, like an IO error
or internal inconsistency
pr_warn() for error conditions that could have been predicated, like
adding a device to an array when it has incompatible metadata
pr_info() for every interesting, very rare events, like an array starting
or stopping, or resync starting or stopping
pr_debug() for everything else.
*/
#include <linux/sched/signal.h>
#include <linux/kthread.h>
#include <linux/blkdev.h>
#include <linux/badblocks.h>
#include <linux/sysctl.h>
#include <linux/seq_file.h>
#include <linux/fs.h>
#include <linux/poll.h>
#include <linux/ctype.h>
#include <linux/string.h>
#include <linux/hdreg.h>
#include <linux/proc_fs.h>
#include <linux/random.h>
#include <linux/module.h>
#include <linux/reboot.h>
#include <linux/file.h>
#include <linux/compat.h>
#include <linux/delay.h>
#include <linux/raid/md_p.h>
#include <linux/raid/md_u.h>
#include <linux/slab.h>
#include <linux/percpu-refcount.h>
#include <trace/events/block.h>
#include "md.h"
#include "md-bitmap.h"
#include "md-cluster.h"
#ifndef MODULE
static void autostart_arrays(int part);
#endif
/* pers_list is a list of registered personalities protected
* by pers_lock.
* pers_lock does extra service to protect accesses to
* mddev->thread when the mutex cannot be held.
*/
static LIST_HEAD(pers_list);
static DEFINE_SPINLOCK(pers_lock);
struct md_cluster_operations *md_cluster_ops;
EXPORT_SYMBOL(md_cluster_ops);
struct module *md_cluster_mod;
EXPORT_SYMBOL(md_cluster_mod);
static DECLARE_WAIT_QUEUE_HEAD(resync_wait);
static struct workqueue_struct *md_wq;
static struct workqueue_struct *md_misc_wq;
static int remove_and_add_spares(struct mddev *mddev,
struct md_rdev *this);
static void mddev_detach(struct mddev *mddev);
/*
* Default number of read corrections we'll attempt on an rdev
* before ejecting it from the array. We divide the read error
* count by 2 for every hour elapsed between read errors.
*/
#define MD_DEFAULT_MAX_CORRECTED_READ_ERRORS 20
/*
* Current RAID-1,4,5 parallel reconstruction 'guaranteed speed limit'
* is 1000 KB/sec, so the extra system load does not show up that much.
* Increase it if you want to have more _guaranteed_ speed. Note that
* the RAID driver will use the maximum available bandwidth if the IO
* subsystem is idle. There is also an 'absolute maximum' reconstruction
* speed limit - in case reconstruction slows down your system despite
* idle IO detection.
*
* you can change it via /proc/sys/dev/raid/speed_limit_min and _max.
* or /sys/block/mdX/md/sync_speed_{min,max}
*/
static int sysctl_speed_limit_min = 1000;
static int sysctl_speed_limit_max = 200000;
static inline int speed_min(struct mddev *mddev)
{
return mddev->sync_speed_min ?
mddev->sync_speed_min : sysctl_speed_limit_min;
}
static inline int speed_max(struct mddev *mddev)
{
return mddev->sync_speed_max ?
mddev->sync_speed_max : sysctl_speed_limit_max;
}
static struct ctl_table_header *raid_table_header;
static struct ctl_table raid_table[] = {
{
.procname = "speed_limit_min",
.data = &sysctl_speed_limit_min,
.maxlen = sizeof(int),
.mode = S_IRUGO|S_IWUSR,
.proc_handler = proc_dointvec,
},
{
.procname = "speed_limit_max",
.data = &sysctl_speed_limit_max,
.maxlen = sizeof(int),
.mode = S_IRUGO|S_IWUSR,
.proc_handler = proc_dointvec,
},
{ }
};
static struct ctl_table raid_dir_table[] = {
{
.procname = "raid",
.maxlen = 0,
.mode = S_IRUGO|S_IXUGO,
.child = raid_table,
},
{ }
};
static struct ctl_table raid_root_table[] = {
{
.procname = "dev",
.maxlen = 0,
.mode = 0555,
.child = raid_dir_table,
},
{ }
};
static const struct block_device_operations md_fops;
static int start_readonly;
/*
* The original mechanism for creating an md device is to create
* a device node in /dev and to open it. This causes races with device-close.
* The preferred method is to write to the "new_array" module parameter.
* This can avoid races.
* Setting create_on_open to false disables the original mechanism
* so all the races disappear.
*/
static bool create_on_open = true;
/* bio_clone_mddev
* like bio_clone_bioset, but with a local bio set
*/
struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs,
struct mddev *mddev)
{
struct bio *b;
if (!mddev || !mddev->bio_set)
return bio_alloc(gfp_mask, nr_iovecs);
b = bio_alloc_bioset(gfp_mask, nr_iovecs, mddev->bio_set);
if (!b)
return NULL;
return b;
}
EXPORT_SYMBOL_GPL(bio_alloc_mddev);
static struct bio *md_bio_alloc_sync(struct mddev *mddev)
{
if (!mddev || !mddev->sync_set)
return bio_alloc(GFP_NOIO, 1);
return bio_alloc_bioset(GFP_NOIO, 1, mddev->sync_set);
}
/*
* We have a system wide 'event count' that is incremented
* on any 'interesting' event, and readers of /proc/mdstat
* can use 'poll' or 'select' to find out when the event
* count increases.
*
* Events are:
* start array, stop array, error, add device, remove device,
* start build, activate spare
*/
static DECLARE_WAIT_QUEUE_HEAD(md_event_waiters);
static atomic_t md_event_count;
void md_new_event(struct mddev *mddev)
{
atomic_inc(&md_event_count);
wake_up(&md_event_waiters);
}
EXPORT_SYMBOL_GPL(md_new_event);
/*
* Enables to iterate over all existing md arrays
* all_mddevs_lock protects this list.
*/
static LIST_HEAD(all_mddevs);
static DEFINE_SPINLOCK(all_mddevs_lock);
/*
* iterates through all used mddevs in the system.
* We take care to grab the all_mddevs_lock whenever navigating
* the list, and to always hold a refcount when unlocked.
* Any code which breaks out of this loop while own
* a reference to the current mddev and must mddev_put it.
*/
#define for_each_mddev(_mddev,_tmp) \
\
for (({ spin_lock(&all_mddevs_lock); \
_tmp = all_mddevs.next; \
_mddev = NULL;}); \
({ if (_tmp != &all_mddevs) \
mddev_get(list_entry(_tmp, struct mddev, all_mddevs));\
spin_unlock(&all_mddevs_lock); \
if (_mddev) mddev_put(_mddev); \
_mddev = list_entry(_tmp, struct mddev, all_mddevs); \
_tmp != &all_mddevs;}); \
({ spin_lock(&all_mddevs_lock); \
_tmp = _tmp->next;}) \
)
/* Rather than calling directly into the personality make_request function,
* IO requests come here first so that we can check if the device is
* being suspended pending a reconfiguration.
* We hold a refcount over the call to ->make_request. By the time that
* call has finished, the bio has been linked into some internal structure
* and so is visible to ->quiesce(), so we don't need the refcount any more.
*/
static bool is_suspended(struct mddev *mddev, struct bio *bio)
{
if (mddev->suspended)
return true;
if (bio_data_dir(bio) != WRITE)
return false;
if (mddev->suspend_lo >= mddev->suspend_hi)
return false;
if (bio->bi_iter.bi_sector >= mddev->suspend_hi)
return false;
if (bio_end_sector(bio) < mddev->suspend_lo)
return false;
return true;
}
void md_handle_request(struct mddev *mddev, struct bio *bio)
{
check_suspended:
rcu_read_lock();
if (is_suspended(mddev, bio)) {
DEFINE_WAIT(__wait);
for (;;) {
prepare_to_wait(&mddev->sb_wait, &__wait,
TASK_UNINTERRUPTIBLE);
if (!is_suspended(mddev, bio))
break;
rcu_read_unlock();
schedule();
rcu_read_lock();
}
finish_wait(&mddev->sb_wait, &__wait);
}
atomic_inc(&mddev->active_io);
rcu_read_unlock();
if (!mddev->pers->make_request(mddev, bio)) {
atomic_dec(&mddev->active_io);
wake_up(&mddev->sb_wait);
goto check_suspended;
}
if (atomic_dec_and_test(&mddev->active_io) && mddev->suspended)
wake_up(&mddev->sb_wait);
}
EXPORT_SYMBOL(md_handle_request);
static blk_qc_t md_make_request(struct request_queue *q, struct bio *bio)
{
const int rw = bio_data_dir(bio);
struct mddev *mddev = q->queuedata;
unsigned int sectors;
int cpu;
blk_queue_split(q, &bio);
if (mddev == NULL || mddev->pers == NULL) {
bio_io_error(bio);
return BLK_QC_T_NONE;
}
if (mddev->ro == 1 && unlikely(rw == WRITE)) {
if (bio_sectors(bio) != 0)
bio->bi_status = BLK_STS_IOERR;
bio_endio(bio);
return BLK_QC_T_NONE;
}
/*
* save the sectors now since our bio can
* go away inside make_request
*/
sectors = bio_sectors(bio);
/* bio could be mergeable after passing to underlayer */
bio->bi_opf &= ~REQ_NOMERGE;
md_handle_request(mddev, bio);
cpu = part_stat_lock();
part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]);
part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw], sectors);
part_stat_unlock();
return BLK_QC_T_NONE;
}
/* mddev_suspend makes sure no new requests are submitted
* to the device, and that any requests that have been submitted
* are completely handled.
* Once mddev_detach() is called and completes, the module will be
* completely unused.
*/
void mddev_suspend(struct mddev *mddev)
{
WARN_ON_ONCE(mddev->thread && current == mddev->thread->tsk);
lockdep_assert_held(&mddev->reconfig_mutex);
if (mddev->suspended++)
return;
synchronize_rcu();
wake_up(&mddev->sb_wait);
set_bit(MD_ALLOW_SB_UPDATE, &mddev->flags);
smp_mb__after_atomic();
wait_event(mddev->sb_wait, atomic_read(&mddev->active_io) == 0);
mddev->pers->quiesce(mddev, 1);
clear_bit_unlock(MD_ALLOW_SB_UPDATE, &mddev->flags);
wait_event(mddev->sb_wait, !test_bit(MD_UPDATING_SB, &mddev->flags));
del_timer_sync(&mddev->safemode_timer);
}
EXPORT_SYMBOL_GPL(mddev_suspend);
void mddev_resume(struct mddev *mddev)
{
lockdep_assert_held(&mddev->reconfig_mutex);
if (--mddev->suspended)
return;
wake_up(&mddev->sb_wait);
mddev->pers->quiesce(mddev, 0);
set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
md_wakeup_thread(mddev->thread);
md_wakeup_thread(mddev->sync_thread); /* possibly kick off a reshape */
}
EXPORT_SYMBOL_GPL(mddev_resume);
int mddev_congested(struct mddev *mddev, int bits)
{
struct md_personality *pers = mddev->pers;
int ret = 0;
rcu_read_lock();
if (mddev->suspended)
ret = 1;
else if (pers && pers->congested)
ret = pers->congested(mddev, bits);
rcu_read_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(mddev_congested);
static int md_congested(void *data, int bits)
{
struct mddev *mddev = data;
return mddev_congested(mddev, bits);
}
/*
* Generic flush handling for md
*/
static void md_end_flush(struct bio *bio)
{
struct md_rdev *rdev = bio->bi_private;
struct mddev *mddev = rdev->mddev;
rdev_dec_pending(rdev, mddev);
if (atomic_dec_and_test(&mddev->flush_pending)) {
/* The pre-request flush has finished */
queue_work(md_wq, &mddev->flush_work);
}
bio_put(bio);
}
static void md_submit_flush_data(struct work_struct *ws);
static void submit_flushes(struct work_struct *ws)
{
struct mddev *mddev = container_of(ws, struct mddev, flush_work);
struct md_rdev *rdev;
INIT_WORK(&mddev->flush_work, md_submit_flush_data);
atomic_set(&mddev->flush_pending, 1);
rcu_read_lock();
rdev_for_each_rcu(rdev, mddev)
if (rdev->raid_disk >= 0 &&
!test_bit(Faulty, &rdev->flags)) {
/* Take two references, one is dropped
* when request finishes, one after
* we reclaim rcu_read_lock
*/
struct bio *bi;
atomic_inc(&rdev->nr_pending);
atomic_inc(&rdev->nr_pending);
rcu_read_unlock();
bi = bio_alloc_mddev(GFP_NOIO, 0, mddev);
bi->bi_end_io = md_end_flush;
bi->bi_private = rdev;
bio_set_dev(bi, rdev->bdev);
bi->bi_opf = REQ_OP_WRITE | REQ_PREFLUSH;
atomic_inc(&mddev->flush_pending);
submit_bio(bi);
rcu_read_lock();
rdev_dec_pending(rdev, mddev);
}
rcu_read_unlock();
if (atomic_dec_and_test(&mddev->flush_pending))
queue_work(md_wq, &mddev->flush_work);
}
static void md_submit_flush_data(struct work_struct *ws)
{
struct mddev *mddev = container_of(ws, struct mddev, flush_work);
struct bio *bio = mddev->flush_bio;
/*
* must reset flush_bio before calling into md_handle_request to avoid a
* deadlock, because other bios passed md_handle_request suspend check
* could wait for this and below md_handle_request could wait for those
* bios because of suspend check
*/
mddev->flush_bio = NULL;
wake_up(&mddev->sb_wait);
if (bio->bi_iter.bi_size == 0)
/* an empty barrier - all done */
bio_endio(bio);
else {
bio->bi_opf &= ~REQ_PREFLUSH;
md_handle_request(mddev, bio);
}
}
void md_flush_request(struct mddev *mddev, struct bio *bio)
{
spin_lock_irq(&mddev->lock);
wait_event_lock_irq(mddev->sb_wait,
!mddev->flush_bio,
mddev->lock);
mddev->flush_bio = bio;
spin_unlock_irq(&mddev->lock);
INIT_WORK(&mddev->flush_work, submit_flushes);
queue_work(md_wq, &mddev->flush_work);
}
EXPORT_SYMBOL(md_flush_request);
static inline struct mddev *mddev_get(struct mddev *mddev)
{
atomic_inc(&mddev->active);
return mddev;
}
static void mddev_delayed_delete(struct work_struct *ws);
static void mddev_put(struct mddev *mddev)
{
struct bio_set *bs = NULL, *sync_bs = NULL;
if (!atomic_dec_and_lock(&mddev->active, &all_mddevs_lock))
return;
if (!mddev->raid_disks && list_empty(&mddev->disks) &&
mddev->ctime == 0 && !mddev->hold_active) {
/* Array is not configured at all, and not held active,
* so destroy it */
list_del_init(&mddev->all_mddevs);
bs = mddev->bio_set;
sync_bs = mddev->sync_set;
mddev->bio_set = NULL;
mddev->sync_set = NULL;
if (mddev->gendisk) {
/* We did a probe so need to clean up. Call
* queue_work inside the spinlock so that
* flush_workqueue() after mddev_find will
* succeed in waiting for the work to be done.
*/
INIT_WORK(&mddev->del_work, mddev_delayed_delete);
queue_work(md_misc_wq, &mddev->del_work);
} else
kfree(mddev);
}
spin_unlock(&all_mddevs_lock);
if (bs)
bioset_free(bs);
if (sync_bs)
bioset_free(sync_bs);
}
static void md_safemode_timeout(struct timer_list *t);
void mddev_init(struct mddev *mddev)
{
mutex_init(&mddev->open_mutex);
mutex_init(&mddev->reconfig_mutex);
mutex_init(&mddev->bitmap_info.mutex);
INIT_LIST_HEAD(&mddev->disks);
INIT_LIST_HEAD(&mddev->all_mddevs);
timer_setup(&mddev->safemode_timer, md_safemode_timeout, 0);
atomic_set(&mddev->active, 1);
atomic_set(&mddev->openers, 0);
atomic_set(&mddev->active_io, 0);
spin_lock_init(&mddev->lock);
atomic_set(&mddev->flush_pending, 0);
init_waitqueue_head(&mddev->sb_wait);
init_waitqueue_head(&mddev->recovery_wait);
mddev->reshape_position = MaxSector;
mddev->reshape_backwards = 0;
mddev->last_sync_action = "none";
mddev->resync_min = 0;
mddev->resync_max = MaxSector;
mddev->level = LEVEL_NONE;
}
EXPORT_SYMBOL_GPL(mddev_init);
static struct mddev *mddev_find(dev_t unit)
{
struct mddev *mddev, *new = NULL;
if (unit && MAJOR(unit) != MD_MAJOR)
unit &= ~((1<<MdpMinorShift)-1);
retry:
spin_lock(&all_mddevs_lock);
if (unit) {
list_for_each_entry(mddev, &all_mddevs, all_mddevs)
if (mddev->unit == unit) {
mddev_get(mddev);
spin_unlock(&all_mddevs_lock);
kfree(new);
return mddev;
}
if (new) {
list_add(&new->all_mddevs, &all_mddevs);
spin_unlock(&all_mddevs_lock);
new->hold_active = UNTIL_IOCTL;
return new;
}
} else if (new) {
/* find an unused unit number */
static int next_minor = 512;
int start = next_minor;
int is_free = 0;
int dev = 0;
while (!is_free) {
dev = MKDEV(MD_MAJOR, next_minor);
next_minor++;
if (next_minor > MINORMASK)
next_minor = 0;
if (next_minor == start) {
/* Oh dear, all in use. */
spin_unlock(&all_mddevs_lock);
kfree(new);
return NULL;
}
is_free = 1;
list_for_each_entry(mddev, &all_mddevs, all_mddevs)
if (mddev->unit == dev) {
is_free = 0;
break;
}
}
new->unit = dev;
new->md_minor = MINOR(dev);
new->hold_active = UNTIL_STOP;
list_add(&new->all_mddevs, &all_mddevs);
spin_unlock(&all_mddevs_lock);
return new;
}
spin_unlock(&all_mddevs_lock);
new = kzalloc(sizeof(*new), GFP_KERNEL);
if (!new)
return NULL;
new->unit = unit;
if (MAJOR(unit) == MD_MAJOR)
new->md_minor = MINOR(unit);
else
new->md_minor = MINOR(unit) >> MdpMinorShift;
mddev_init(new);
goto retry;
}
static struct attribute_group md_redundancy_group;
void mddev_unlock(struct mddev *mddev)
{
if (mddev->to_remove) {
/* These cannot be removed under reconfig_mutex as
* an access to the files will try to take reconfig_mutex
* while holding the file unremovable, which leads to
* a deadlock.
* So hold set sysfs_active while the remove in happeing,
* and anything else which might set ->to_remove or my
* otherwise change the sysfs namespace will fail with
* -EBUSY if sysfs_active is still set.
* We set sysfs_active under reconfig_mutex and elsewhere
* test it under the same mutex to ensure its correct value
* is seen.
*/
struct attribute_group *to_remove = mddev->to_remove;
mddev->to_remove = NULL;
mddev->sysfs_active = 1;
mutex_unlock(&mddev->reconfig_mutex);
if (mddev->kobj.sd) {
if (to_remove != &md_redundancy_group)
sysfs_remove_group(&mddev->kobj, to_remove);
if (mddev->pers == NULL ||
mddev->pers->sync_request == NULL) {
sysfs_remove_group(&mddev->kobj, &md_redundancy_group);
if (mddev->sysfs_action)
sysfs_put(mddev->sysfs_action);
mddev->sysfs_action = NULL;
}
}
mddev->sysfs_active = 0;
} else
mutex_unlock(&mddev->reconfig_mutex);
/* As we've dropped the mutex we need a spinlock to
* make sure the thread doesn't disappear
*/
spin_lock(&pers_lock);
md_wakeup_thread(mddev->thread);
wake_up(&mddev->sb_wait);
spin_unlock(&pers_lock);
}
EXPORT_SYMBOL_GPL(mddev_unlock);
struct md_rdev *md_find_rdev_nr_rcu(struct mddev *mddev, int nr)
{
struct md_rdev *rdev;
rdev_for_each_rcu(rdev, mddev)
if (rdev->desc_nr == nr)
return rdev;
return NULL;
}
EXPORT_SYMBOL_GPL(md_find_rdev_nr_rcu);
static struct md_rdev *find_rdev(struct mddev *mddev, dev_t dev)
{
struct md_rdev *rdev;
rdev_for_each(rdev, mddev)
if (rdev->bdev->bd_dev == dev)
return rdev;
return NULL;
}
static struct md_rdev *find_rdev_rcu(struct mddev *mddev, dev_t dev)
{
struct md_rdev *rdev;
rdev_for_each_rcu(rdev, mddev)
if (rdev->bdev->bd_dev == dev)
return rdev;
return NULL;
}
static struct md_personality *find_pers(int level, char *clevel)
{
struct md_personality *pers;
list_for_each_entry(pers, &pers_list, list) {
if (level != LEVEL_NONE && pers->level == level)
return pers;
if (strcmp(pers->name, clevel)==0)
return pers;
}
return NULL;
}
/* return the offset of the super block in 512byte sectors */
static inline sector_t calc_dev_sboffset(struct md_rdev *rdev)
{
sector_t num_sectors = i_size_read(rdev->bdev->bd_inode) / 512;
return MD_NEW_SIZE_SECTORS(num_sectors);
}
static int alloc_disk_sb(struct md_rdev *rdev)
{
rdev->sb_page = alloc_page(GFP_KERNEL);
if (!rdev->sb_page)
return -ENOMEM;
return 0;
}
void md_rdev_clear(struct md_rdev *rdev)
{
if (rdev->sb_page) {
put_page(rdev->sb_page);
rdev->sb_loaded = 0;
rdev->sb_page = NULL;
rdev->sb_start = 0;
rdev->sectors = 0;
}
if (rdev->bb_page) {
put_page(rdev->bb_page);
rdev->bb_page = NULL;
}
badblocks_exit(&rdev->badblocks);
}
EXPORT_SYMBOL_GPL(md_rdev_clear);
static void super_written(struct bio *bio)
{
struct md_rdev *rdev = bio->bi_private;
struct mddev *mddev = rdev->mddev;
if (bio->bi_status) {
pr_err("md: super_written gets error=%d\n", bio->bi_status);
md_error(mddev, rdev);
if (!test_bit(Faulty, &rdev->flags)
&& (bio->bi_opf & MD_FAILFAST)) {
set_bit(MD_SB_NEED_REWRITE, &mddev->sb_flags);
set_bit(LastDev, &rdev->flags);
}
} else
clear_bit(LastDev, &rdev->flags);
if (atomic_dec_and_test(&mddev->pending_writes))
wake_up(&mddev->sb_wait);
rdev_dec_pending(rdev, mddev);
bio_put(bio);
}
void md_super_write(struct mddev *mddev, struct md_rdev *rdev,
sector_t sector, int size, struct page *page)
{
/* write first size bytes of page to sector of rdev
* Increment mddev->pending_writes before returning
* and decrement it on completion, waking up sb_wait
* if zero is reached.
* If an error occurred, call md_error
*/
struct bio *bio;
int ff = 0;
if (test_bit(Faulty, &rdev->flags))
return;
bio = md_bio_alloc_sync(mddev);
atomic_inc(&rdev->nr_pending);
bio_set_dev(bio, rdev->meta_bdev ? rdev->meta_bdev : rdev->bdev);
bio->bi_iter.bi_sector = sector;
bio_add_page(bio, page, size, 0);
bio->bi_private = rdev;
bio->bi_end_io = super_written;
if (test_bit(MD_FAILFAST_SUPPORTED, &mddev->flags) &&
test_bit(FailFast, &rdev->flags) &&
!test_bit(LastDev, &rdev->flags))
ff = MD_FAILFAST;
bio->bi_opf = REQ_OP_WRITE | REQ_SYNC | REQ_PREFLUSH | REQ_FUA | ff;
atomic_inc(&mddev->pending_writes);
submit_bio(bio);
}
int md_super_wait(struct mddev *mddev)
{
/* wait for all superblock writes that were scheduled to complete */
wait_event(mddev->sb_wait, atomic_read(&mddev->pending_writes)==0);
if (test_and_clear_bit(MD_SB_NEED_REWRITE, &mddev->sb_flags))
return -EAGAIN;
return 0;
}
int sync_page_io(struct md_rdev *rdev, sector_t sector, int size,
struct page *page, int op, int op_flags, bool metadata_op)
{
struct bio *bio = md_bio_alloc_sync(rdev->mddev);
int ret;
if (metadata_op && rdev->meta_bdev)
bio_set_dev(bio, rdev->meta_bdev);
else
bio_set_dev(bio, rdev->bdev);
bio_set_op_attrs(bio, op, op_flags);
if (metadata_op)
bio->bi_iter.bi_sector = sector + rdev->sb_start;
else if (rdev->mddev->reshape_position != MaxSector &&
(rdev->mddev->reshape_backwards ==
(sector >= rdev->mddev->reshape_position)))
bio->bi_iter.bi_sector = sector + rdev->new_data_offset;
else
bio->bi_iter.bi_sector = sector + rdev->data_offset;
bio_add_page(bio, page, size, 0);
submit_bio_wait(bio);
ret = !bio->bi_status;
bio_put(bio);
return ret;
}
EXPORT_SYMBOL_GPL(sync_page_io);
static int read_disk_sb(struct md_rdev *rdev, int size)
{
char b[BDEVNAME_SIZE];
if (rdev->sb_loaded)
return 0;
if (!sync_page_io(rdev, 0, size, rdev->sb_page, REQ_OP_READ, 0, true))
goto fail;
rdev->sb_loaded = 1;
return 0;
fail:
pr_err("md: disabled device %s, could not read superblock.\n",
bdevname(rdev->bdev,b));
return -EINVAL;
}
static int md_uuid_equal(mdp_super_t *sb1, mdp_super_t *sb2)
{
return sb1->set_uuid0 == sb2->set_uuid0 &&
sb1->set_uuid1 == sb2->set_uuid1 &&
sb1->set_uuid2 == sb2->set_uuid2 &&
sb1->set_uuid3 == sb2->set_uuid3;
}
static int md_sb_equal(mdp_super_t *sb1, mdp_super_t *sb2)
{
int ret;
mdp_super_t *tmp1, *tmp2;
tmp1 = kmalloc(sizeof(*tmp1),GFP_KERNEL);
tmp2 = kmalloc(sizeof(*tmp2),GFP_KERNEL);
if (!tmp1 || !tmp2) {
ret = 0;
goto abort;
}
*tmp1 = *sb1;
*tmp2 = *sb2;
/*
* nr_disks is not constant
*/
tmp1->nr_disks = 0;
tmp2->nr_disks = 0;
ret = (memcmp(tmp1, tmp2, MD_SB_GENERIC_CONSTANT_WORDS * 4) == 0);
abort:
kfree(tmp1);
kfree(tmp2);
return ret;
}
static u32 md_csum_fold(u32 csum)
{
csum = (csum & 0xffff) + (csum >> 16);
return (csum & 0xffff) + (csum >> 16);
}
static unsigned int calc_sb_csum(mdp_super_t *sb)
{
u64 newcsum = 0;
u32 *sb32 = (u32*)sb;
int i;
unsigned int disk_csum, csum;
disk_csum = sb->sb_csum;
sb->sb_csum = 0;
for (i = 0; i < MD_SB_BYTES/4 ; i++)
newcsum += sb32[i];
csum = (newcsum & 0xffffffff) + (newcsum>>32);
#ifdef CONFIG_ALPHA
/* This used to use csum_partial, which was wrong for several
* reasons including that different results are returned on
* different architectures. It isn't critical that we get exactly
* the same return value as before (we always csum_fold before
* testing, and that removes any differences). However as we
* know that csum_partial always returned a 16bit value on
* alphas, do a fold to maximise conformity to previous behaviour.
*/
sb->sb_csum = md_csum_fold(disk_csum);
#else
sb->sb_csum = disk_csum;
#endif
return csum;
}
/*
* Handle superblock details.
* We want to be able to handle multiple superblock formats
* so we have a common interface to them all, and an array of
* different handlers.
* We rely on user-space to write the initial superblock, and support
* reading and updating of superblocks.
* Interface methods are:
* int load_super(struct md_rdev *dev, struct md_rdev *refdev, int minor_version)
* loads and validates a superblock on dev.
* if refdev != NULL, compare superblocks on both devices
* Return:
* 0 - dev has a superblock that is compatible with refdev
* 1 - dev has a superblock that is compatible and newer than refdev
* so dev should be used as the refdev in future
* -EINVAL superblock incompatible or invalid
* -othererror e.g. -EIO
*
* int validate_super(struct mddev *mddev, struct md_rdev *dev)
* Verify that dev is acceptable into mddev.
* The first time, mddev->raid_disks will be 0, and data from
* dev should be merged in. Subsequent calls check that dev
* is new enough. Return 0 or -EINVAL
*
* void sync_super(struct mddev *mddev, struct md_rdev *dev)
* Update the superblock for rdev with data in mddev
* This does not write to disc.
*
*/
struct super_type {
char *name;
struct module *owner;
int (*load_super)(struct md_rdev *rdev,
struct md_rdev *refdev,
int minor_version);
int (*validate_super)(struct mddev *mddev,
struct md_rdev *rdev);
void (*sync_super)(struct mddev *mddev,
struct md_rdev *rdev);
unsigned long long (*rdev_size_change)(struct md_rdev *rdev,
sector_t num_sectors);
int (*allow_new_offset)(struct md_rdev *rdev,
unsigned long long new_offset);
};