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linux/drivers/md/raid10.c
NeilBrown abbf098e6e md/raid10: preferentially read from replacement device if possible. 
When reading (for array reads, not for recovery etc) we read from the
replacement device if it has recovered far enough.
This requires storing the chosen rdev in the 'r10_bio' so we can make
sure to drop the ref on the right device when the read finishes.

Signed-off-by: NeilBrown <neilb@suse.de>
2011-12-23 10:17:54 +11:00

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/*
* raid10.c : Multiple Devices driver for Linux
*
* Copyright (C) 2000-2004 Neil Brown
*
* RAID-10 support for md.
*
* Base on code in raid1.c. See raid1.c for further copyright information.
*
*
* 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.
*/
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/blkdev.h>
#include <linux/module.h>
#include <linux/seq_file.h>
#include <linux/ratelimit.h>
#include "md.h"
#include "raid10.h"
#include "raid0.h"
#include "bitmap.h"
/*
* RAID10 provides a combination of RAID0 and RAID1 functionality.
* The layout of data is defined by
* chunk_size
* raid_disks
* near_copies (stored in low byte of layout)
* far_copies (stored in second byte of layout)
* far_offset (stored in bit 16 of layout )
*
* The data to be stored is divided into chunks using chunksize.
* Each device is divided into far_copies sections.
* In each section, chunks are laid out in a style similar to raid0, but
* near_copies copies of each chunk is stored (each on a different drive).
* The starting device for each section is offset near_copies from the starting
* device of the previous section.
* Thus they are (near_copies*far_copies) of each chunk, and each is on a different
* drive.
* near_copies and far_copies must be at least one, and their product is at most
* raid_disks.
*
* If far_offset is true, then the far_copies are handled a bit differently.
* The copies are still in different stripes, but instead of be very far apart
* on disk, there are adjacent stripes.
*/
/*
* Number of guaranteed r10bios in case of extreme VM load:
*/
#define NR_RAID10_BIOS 256
/* When there are this many requests queue to be written by
* the raid10 thread, we become 'congested' to provide back-pressure
* for writeback.
*/
static int max_queued_requests = 1024;
static void allow_barrier(struct r10conf *conf);
static void lower_barrier(struct r10conf *conf);
static void * r10bio_pool_alloc(gfp_t gfp_flags, void *data)
{
struct r10conf *conf = data;
int size = offsetof(struct r10bio, devs[conf->copies]);
/* allocate a r10bio with room for raid_disks entries in the
* bios array */
return kzalloc(size, gfp_flags);
}
static void r10bio_pool_free(void *r10_bio, void *data)
{
kfree(r10_bio);
}
/* Maximum size of each resync request */
#define RESYNC_BLOCK_SIZE (64*1024)
#define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
/* amount of memory to reserve for resync requests */
#define RESYNC_WINDOW (1024*1024)
/* maximum number of concurrent requests, memory permitting */
#define RESYNC_DEPTH (32*1024*1024/RESYNC_BLOCK_SIZE)
/*
* When performing a resync, we need to read and compare, so
* we need as many pages are there are copies.
* When performing a recovery, we need 2 bios, one for read,
* one for write (we recover only one drive per r10buf)
*
*/
static void * r10buf_pool_alloc(gfp_t gfp_flags, void *data)
{
struct r10conf *conf = data;
struct page *page;
struct r10bio *r10_bio;
struct bio *bio;
int i, j;
int nalloc;
r10_bio = r10bio_pool_alloc(gfp_flags, conf);
if (!r10_bio)
return NULL;
if (test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery))
nalloc = conf->copies; /* resync */
else
nalloc = 2; /* recovery */
/*
* Allocate bios.
*/
for (j = nalloc ; j-- ; ) {
bio = bio_kmalloc(gfp_flags, RESYNC_PAGES);
if (!bio)
goto out_free_bio;
r10_bio->devs[j].bio = bio;
if (!conf->have_replacement)
continue;
bio = bio_kmalloc(gfp_flags, RESYNC_PAGES);
if (!bio)
goto out_free_bio;
r10_bio->devs[j].repl_bio = bio;
}
/*
* Allocate RESYNC_PAGES data pages and attach them
* where needed.
*/
for (j = 0 ; j < nalloc; j++) {
struct bio *rbio = r10_bio->devs[j].repl_bio;
bio = r10_bio->devs[j].bio;
for (i = 0; i < RESYNC_PAGES; i++) {
if (j == 1 && !test_bit(MD_RECOVERY_SYNC,
&conf->mddev->recovery)) {
/* we can share bv_page's during recovery */
struct bio *rbio = r10_bio->devs[0].bio;
page = rbio->bi_io_vec[i].bv_page;
get_page(page);
} else
page = alloc_page(gfp_flags);
if (unlikely(!page))
goto out_free_pages;
bio->bi_io_vec[i].bv_page = page;
if (rbio)
rbio->bi_io_vec[i].bv_page = page;
}
}
return r10_bio;
out_free_pages:
for ( ; i > 0 ; i--)
safe_put_page(bio->bi_io_vec[i-1].bv_page);
while (j--)
for (i = 0; i < RESYNC_PAGES ; i++)
safe_put_page(r10_bio->devs[j].bio->bi_io_vec[i].bv_page);
j = -1;
out_free_bio:
while (++j < nalloc) {
bio_put(r10_bio->devs[j].bio);
if (r10_bio->devs[j].repl_bio)
bio_put(r10_bio->devs[j].repl_bio);
}
r10bio_pool_free(r10_bio, conf);
return NULL;
}
static void r10buf_pool_free(void *__r10_bio, void *data)
{
int i;
struct r10conf *conf = data;
struct r10bio *r10bio = __r10_bio;
int j;
for (j=0; j < conf->copies; j++) {
struct bio *bio = r10bio->devs[j].bio;
if (bio) {
for (i = 0; i < RESYNC_PAGES; i++) {
safe_put_page(bio->bi_io_vec[i].bv_page);
bio->bi_io_vec[i].bv_page = NULL;
}
bio_put(bio);
}
bio = r10bio->devs[j].repl_bio;
if (bio)
bio_put(bio);
}
r10bio_pool_free(r10bio, conf);
}
static void put_all_bios(struct r10conf *conf, struct r10bio *r10_bio)
{
int i;
for (i = 0; i < conf->copies; i++) {
struct bio **bio = & r10_bio->devs[i].bio;
if (!BIO_SPECIAL(*bio))
bio_put(*bio);
*bio = NULL;
bio = &r10_bio->devs[i].repl_bio;
if (r10_bio->read_slot < 0 && !BIO_SPECIAL(*bio))
bio_put(*bio);
*bio = NULL;
}
}
static void free_r10bio(struct r10bio *r10_bio)
{
struct r10conf *conf = r10_bio->mddev->private;
put_all_bios(conf, r10_bio);
mempool_free(r10_bio, conf->r10bio_pool);
}
static void put_buf(struct r10bio *r10_bio)
{
struct r10conf *conf = r10_bio->mddev->private;
mempool_free(r10_bio, conf->r10buf_pool);
lower_barrier(conf);
}
static void reschedule_retry(struct r10bio *r10_bio)
{
unsigned long flags;
struct mddev *mddev = r10_bio->mddev;
struct r10conf *conf = mddev->private;
spin_lock_irqsave(&conf->device_lock, flags);
list_add(&r10_bio->retry_list, &conf->retry_list);
conf->nr_queued ++;
spin_unlock_irqrestore(&conf->device_lock, flags);
/* wake up frozen array... */
wake_up(&conf->wait_barrier);
md_wakeup_thread(mddev->thread);
}
/*
* raid_end_bio_io() is called when we have finished servicing a mirrored
* operation and are ready to return a success/failure code to the buffer
* cache layer.
*/
static void raid_end_bio_io(struct r10bio *r10_bio)
{
struct bio *bio = r10_bio->master_bio;
int done;
struct r10conf *conf = r10_bio->mddev->private;
if (bio->bi_phys_segments) {
unsigned long flags;
spin_lock_irqsave(&conf->device_lock, flags);
bio->bi_phys_segments--;
done = (bio->bi_phys_segments == 0);
spin_unlock_irqrestore(&conf->device_lock, flags);
} else
done = 1;
if (!test_bit(R10BIO_Uptodate, &r10_bio->state))
clear_bit(BIO_UPTODATE, &bio->bi_flags);
if (done) {
bio_endio(bio, 0);
/*
* Wake up any possible resync thread that waits for the device
* to go idle.
*/
allow_barrier(conf);
}
free_r10bio(r10_bio);
}
/*
* Update disk head position estimator based on IRQ completion info.
*/
static inline void update_head_pos(int slot, struct r10bio *r10_bio)
{
struct r10conf *conf = r10_bio->mddev->private;
conf->mirrors[r10_bio->devs[slot].devnum].head_position =
r10_bio->devs[slot].addr + (r10_bio->sectors);
}
/*
* Find the disk number which triggered given bio
*/
static int find_bio_disk(struct r10conf *conf, struct r10bio *r10_bio,
struct bio *bio, int *slotp, int *replp)
{
int slot;
int repl = 0;
for (slot = 0; slot < conf->copies; slot++) {
if (r10_bio->devs[slot].bio == bio)
break;
if (r10_bio->devs[slot].repl_bio == bio) {
repl = 1;
break;
}
}
BUG_ON(slot == conf->copies);
update_head_pos(slot, r10_bio);
if (slotp)
*slotp = slot;
if (replp)
*replp = repl;
return r10_bio->devs[slot].devnum;
}
static void raid10_end_read_request(struct bio *bio, int error)
{
int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
struct r10bio *r10_bio = bio->bi_private;
int slot, dev;
struct md_rdev *rdev;
struct r10conf *conf = r10_bio->mddev->private;
slot = r10_bio->read_slot;
dev = r10_bio->devs[slot].devnum;
rdev = r10_bio->devs[slot].rdev;
/*
* this branch is our 'one mirror IO has finished' event handler:
*/
update_head_pos(slot, r10_bio);
if (uptodate) {
/*
* Set R10BIO_Uptodate in our master bio, so that
* we will return a good error code to the higher
* levels even if IO on some other mirrored buffer fails.
*
* The 'master' represents the composite IO operation to
* user-side. So if something waits for IO, then it will
* wait for the 'master' bio.
*/
set_bit(R10BIO_Uptodate, &r10_bio->state);
raid_end_bio_io(r10_bio);
rdev_dec_pending(rdev, conf->mddev);
} else {
/*
* oops, read error - keep the refcount on the rdev
*/
char b[BDEVNAME_SIZE];
printk_ratelimited(KERN_ERR
"md/raid10:%s: %s: rescheduling sector %llu\n",
mdname(conf->mddev),
bdevname(rdev->bdev, b),
(unsigned long long)r10_bio->sector);
set_bit(R10BIO_ReadError, &r10_bio->state);
reschedule_retry(r10_bio);
}
}
static void close_write(struct r10bio *r10_bio)
{
/* clear the bitmap if all writes complete successfully */
bitmap_endwrite(r10_bio->mddev->bitmap, r10_bio->sector,
r10_bio->sectors,
!test_bit(R10BIO_Degraded, &r10_bio->state),
0);
md_write_end(r10_bio->mddev);
}
static void one_write_done(struct r10bio *r10_bio)
{
if (atomic_dec_and_test(&r10_bio->remaining)) {
if (test_bit(R10BIO_WriteError, &r10_bio->state))
reschedule_retry(r10_bio);
else {
close_write(r10_bio);
if (test_bit(R10BIO_MadeGood, &r10_bio->state))
reschedule_retry(r10_bio);
else
raid_end_bio_io(r10_bio);
}
}
}
static void raid10_end_write_request(struct bio *bio, int error)
{
int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
struct r10bio *r10_bio = bio->bi_private;
int dev;
int dec_rdev = 1;
struct r10conf *conf = r10_bio->mddev->private;
int slot;
dev = find_bio_disk(conf, r10_bio, bio, &slot, NULL);
/*
* this branch is our 'one mirror IO has finished' event handler:
*/
if (!uptodate) {
set_bit(WriteErrorSeen, &conf->mirrors[dev].rdev->flags);
set_bit(R10BIO_WriteError, &r10_bio->state);
dec_rdev = 0;
} else {
/*
* Set R10BIO_Uptodate in our master bio, so that
* we will return a good error code for to the higher
* levels even if IO on some other mirrored buffer fails.
*
* The 'master' represents the composite IO operation to
* user-side. So if something waits for IO, then it will
* wait for the 'master' bio.
*/
sector_t first_bad;
int bad_sectors;
set_bit(R10BIO_Uptodate, &r10_bio->state);
/* Maybe we can clear some bad blocks. */
if (is_badblock(conf->mirrors[dev].rdev,
r10_bio->devs[slot].addr,
r10_bio->sectors,
&first_bad, &bad_sectors)) {
bio_put(bio);
r10_bio->devs[slot].bio = IO_MADE_GOOD;
dec_rdev = 0;
set_bit(R10BIO_MadeGood, &r10_bio->state);
}
}
/*
*
* Let's see if all mirrored write operations have finished
* already.
*/
one_write_done(r10_bio);
if (dec_rdev)
rdev_dec_pending(conf->mirrors[dev].rdev, conf->mddev);
}
/*
* RAID10 layout manager
* As well as the chunksize and raid_disks count, there are two
* parameters: near_copies and far_copies.
* near_copies * far_copies must be <= raid_disks.
* Normally one of these will be 1.
* If both are 1, we get raid0.
* If near_copies == raid_disks, we get raid1.
*
* Chunks are laid out in raid0 style with near_copies copies of the
* first chunk, followed by near_copies copies of the next chunk and
* so on.
* If far_copies > 1, then after 1/far_copies of the array has been assigned
* as described above, we start again with a device offset of near_copies.
* So we effectively have another copy of the whole array further down all
* the drives, but with blocks on different drives.
* With this layout, and block is never stored twice on the one device.
*
* raid10_find_phys finds the sector offset of a given virtual sector
* on each device that it is on.
*
* raid10_find_virt does the reverse mapping, from a device and a
* sector offset to a virtual address
*/
static void raid10_find_phys(struct r10conf *conf, struct r10bio *r10bio)
{
int n,f;
sector_t sector;
sector_t chunk;
sector_t stripe;
int dev;
int slot = 0;
/* now calculate first sector/dev */
chunk = r10bio->sector >> conf->chunk_shift;
sector = r10bio->sector & conf->chunk_mask;
chunk *= conf->near_copies;
stripe = chunk;
dev = sector_div(stripe, conf->raid_disks);
if (conf->far_offset)
stripe *= conf->far_copies;
sector += stripe << conf->chunk_shift;
/* and calculate all the others */
for (n=0; n < conf->near_copies; n++) {
int d = dev;
sector_t s = sector;
r10bio->devs[slot].addr = sector;
r10bio->devs[slot].devnum = d;
slot++;
for (f = 1; f < conf->far_copies; f++) {
d += conf->near_copies;
if (d >= conf->raid_disks)
d -= conf->raid_disks;
s += conf->stride;
r10bio->devs[slot].devnum = d;
r10bio->devs[slot].addr = s;
slot++;
}
dev++;
if (dev >= conf->raid_disks) {
dev = 0;
sector += (conf->chunk_mask + 1);
}
}
BUG_ON(slot != conf->copies);
}
static sector_t raid10_find_virt(struct r10conf *conf, sector_t sector, int dev)
{
sector_t offset, chunk, vchunk;
offset = sector & conf->chunk_mask;
if (conf->far_offset) {
int fc;
chunk = sector >> conf->chunk_shift;
fc = sector_div(chunk, conf->far_copies);
dev -= fc * conf->near_copies;
if (dev < 0)
dev += conf->raid_disks;
} else {
while (sector >= conf->stride) {
sector -= conf->stride;
if (dev < conf->near_copies)
dev += conf->raid_disks - conf->near_copies;
else
dev -= conf->near_copies;
}
chunk = sector >> conf->chunk_shift;
}
vchunk = chunk * conf->raid_disks + dev;
sector_div(vchunk, conf->near_copies);
return (vchunk << conf->chunk_shift) + offset;
}
/**
* raid10_mergeable_bvec -- tell bio layer if a two requests can be merged
* @q: request queue
* @bvm: properties of new bio
* @biovec: the request that could be merged to it.
*
* Return amount of bytes we can accept at this offset
* If near_copies == raid_disk, there are no striping issues,
* but in that case, the function isn't called at all.
*/
static int raid10_mergeable_bvec(struct request_queue *q,
struct bvec_merge_data *bvm,
struct bio_vec *biovec)
{
struct mddev *mddev = q->queuedata;
sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
int max;
unsigned int chunk_sectors = mddev->chunk_sectors;
unsigned int bio_sectors = bvm->bi_size >> 9;
max = (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9;
if (max < 0) max = 0; /* bio_add cannot handle a negative return */
if (max <= biovec->bv_len && bio_sectors == 0)
return biovec->bv_len;
else
return max;
}
/*
* This routine returns the disk from which the requested read should
* be done. There is a per-array 'next expected sequential IO' sector
* number - if this matches on the next IO then we use the last disk.
* There is also a per-disk 'last know head position' sector that is
* maintained from IRQ contexts, both the normal and the resync IO
* completion handlers update this position correctly. If there is no
* perfect sequential match then we pick the disk whose head is closest.
*
* If there are 2 mirrors in the same 2 devices, performance degrades
* because position is mirror, not device based.
*
* The rdev for the device selected will have nr_pending incremented.
*/
/*
* FIXME: possibly should rethink readbalancing and do it differently
* depending on near_copies / far_copies geometry.
*/
static struct md_rdev *read_balance(struct r10conf *conf,
struct r10bio *r10_bio,
int *max_sectors)
{
const sector_t this_sector = r10_bio->sector;
int disk, slot;
int sectors = r10_bio->sectors;
int best_good_sectors;
sector_t new_distance, best_dist;
struct md_rdev *rdev, *best_rdev;
int do_balance;
int best_slot;
raid10_find_phys(conf, r10_bio);
rcu_read_lock();
retry:
sectors = r10_bio->sectors;
best_slot = -1;
best_rdev = NULL;
best_dist = MaxSector;
best_good_sectors = 0;
do_balance = 1;
/*
* Check if we can balance. We can balance on the whole
* device if no resync is going on (recovery is ok), or below
* the resync window. We take the first readable disk when
* above the resync window.
*/
if (conf->mddev->recovery_cp < MaxSector
&& (this_sector + sectors >= conf->next_resync))
do_balance = 0;
for (slot = 0; slot < conf->copies ; slot++) {
sector_t first_bad;
int bad_sectors;
sector_t dev_sector;
if (r10_bio->devs[slot].bio == IO_BLOCKED)
continue;
disk = r10_bio->devs[slot].devnum;
rdev = rcu_dereference(conf->mirrors[disk].replacement);
if (rdev == NULL || test_bit(Faulty, &rdev->flags) ||
r10_bio->devs[slot].addr + sectors > rdev->recovery_offset)
rdev = rcu_dereference(conf->mirrors[disk].rdev);
if (rdev == NULL)
continue;
if (test_bit(Faulty, &rdev->flags))
continue;
if (!test_bit(In_sync, &rdev->flags) &&
r10_bio->devs[slot].addr + sectors > rdev->recovery_offset)
continue;
dev_sector = r10_bio->devs[slot].addr;
if (is_badblock(rdev, dev_sector, sectors,
&first_bad, &bad_sectors)) {
if (best_dist < MaxSector)
/* Already have a better slot */
continue;
if (first_bad <= dev_sector) {
/* Cannot read here. If this is the
* 'primary' device, then we must not read
* beyond 'bad_sectors' from another device.
*/
bad_sectors -= (dev_sector - first_bad);
if (!do_balance && sectors > bad_sectors)
sectors = bad_sectors;
if (best_good_sectors > sectors)
best_good_sectors = sectors;
} else {
sector_t good_sectors =
first_bad - dev_sector;
if (good_sectors > best_good_sectors) {
best_good_sectors = good_sectors;
best_slot = slot;
best_rdev = rdev;
}
if (!do_balance)
/* Must read from here */
break;
}
continue;
} else
best_good_sectors = sectors;
if (!do_balance)
break;
/* This optimisation is debatable, and completely destroys
* sequential read speed for 'far copies' arrays. So only
* keep it for 'near' arrays, and review those later.
*/
if (conf->near_copies > 1 && !atomic_read(&rdev->nr_pending))
break;
/* for far > 1 always use the lowest address */
if (conf->far_copies > 1)
new_distance = r10_bio->devs[slot].addr;
else
new_distance = abs(r10_bio->devs[slot].addr -
conf->mirrors[disk].head_position);
if (new_distance < best_dist) {
best_dist = new_distance;
best_slot = slot;
best_rdev = rdev;
}
}
if (slot >= conf->copies) {
slot = best_slot;
rdev = best_rdev;
}
if (slot >= 0) {
atomic_inc(&rdev->nr_pending);
if (test_bit(Faulty, &rdev->flags)) {
/* Cannot risk returning a device that failed
* before we inc'ed nr_pending
*/
rdev_dec_pending(rdev, conf->mddev);
goto retry;
}
r10_bio->read_slot = slot;
} else
rdev = NULL;
rcu_read_unlock();
*max_sectors = best_good_sectors;
return rdev;
}
static int raid10_congested(void *data, int bits)
{
struct mddev *mddev = data;
struct r10conf *conf = mddev->private;
int i, ret = 0;
if ((bits & (1 << BDI_async_congested)) &&
conf->pending_count >= max_queued_requests)
return 1;
if (mddev_congested(mddev, bits))
return 1;
rcu_read_lock();
for (i = 0; i < conf->raid_disks && ret == 0; i++) {
struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
if (rdev && !test_bit(Faulty, &rdev->flags)) {
struct request_queue *q = bdev_get_queue(rdev->bdev);
ret |= bdi_congested(&q->backing_dev_info, bits);
}
}
rcu_read_unlock();
return ret;
}
static void flush_pending_writes(struct r10conf *conf)
{
/* Any writes that have been queued but are awaiting
* bitmap updates get flushed here.
*/
spin_lock_irq(&conf->device_lock);
if (conf->pending_bio_list.head) {
struct bio *bio;
bio = bio_list_get(&conf->pending_bio_list);
conf->pending_count = 0;
spin_unlock_irq(&conf->device_lock);
/* flush any pending bitmap writes to disk
* before proceeding w/ I/O */
bitmap_unplug(conf->mddev->bitmap);
wake_up(&conf->wait_barrier);
while (bio) { /* submit pending writes */
struct bio *next = bio->bi_next;
bio->bi_next = NULL;
generic_make_request(bio);
bio = next;
}
} else
spin_unlock_irq(&conf->device_lock);
}
/* Barriers....
* Sometimes we need to suspend IO while we do something else,
* either some resync/recovery, or reconfigure the array.
* To do this we raise a 'barrier'.
* The 'barrier' is a counter that can be raised multiple times
* to count how many activities are happening which preclude
* normal IO.
* We can only raise the barrier if there is no pending IO.
* i.e. if nr_pending == 0.
* We choose only to raise the barrier if no-one is waiting for the
* barrier to go down. This means that as soon as an IO request
* is ready, no other operations which require a barrier will start
* until the IO request has had a chance.
*
* So: regular IO calls 'wait_barrier'. When that returns there
* is no backgroup IO happening, It must arrange to call
* allow_barrier when it has finished its IO.
* backgroup IO calls must call raise_barrier. Once that returns
* there is no normal IO happeing. It must arrange to call
* lower_barrier when the particular background IO completes.
*/
static void raise_barrier(struct r10conf *conf, int force)
{
BUG_ON(force && !conf->barrier);
spin_lock_irq(&conf->resync_lock);
/* Wait until no block IO is waiting (unless 'force') */
wait_event_lock_irq(conf->wait_barrier, force || !conf->nr_waiting,
conf->resync_lock, );
/* block any new IO from starting */
conf->barrier++;
/* Now wait for all pending IO to complete */
wait_event_lock_irq(conf->wait_barrier,
!conf->nr_pending && conf->barrier < RESYNC_DEPTH,
conf->resync_lock, );
spin_unlock_irq(&conf->resync_lock);
}
static void lower_barrier(struct r10conf *conf)
{
unsigned long flags;
spin_lock_irqsave(&conf->resync_lock, flags);
conf->barrier--;
spin_unlock_irqrestore(&conf->resync_lock, flags);
wake_up(&conf->wait_barrier);
}
static void wait_barrier(struct r10conf *conf)
{
spin_lock_irq(&conf->resync_lock);
if (conf->barrier) {
conf->nr_waiting++;
wait_event_lock_irq(conf->wait_barrier, !conf->barrier,
conf->resync_lock,
);
conf->nr_waiting--;
}
conf->nr_pending++;
spin_unlock_irq(&conf->resync_lock);
}
static void allow_barrier(struct r10conf *conf)
{
unsigned long flags;
spin_lock_irqsave(&conf->resync_lock, flags);
conf->nr_pending--;
spin_unlock_irqrestore(&conf->resync_lock, flags);
wake_up(&conf->wait_barrier);
}
static void freeze_array(struct r10conf *conf)
{
/* stop syncio and normal IO and wait for everything to
* go quiet.
* We increment barrier and nr_waiting, and then
* wait until nr_pending match nr_queued+1
* This is called in the context of one normal IO request
* that has failed. Thus any sync request that might be pending
* will be blocked by nr_pending, and we need to wait for
* pending IO requests to complete or be queued for re-try.
* Thus the number queued (nr_queued) plus this request (1)
* must match the number of pending IOs (nr_pending) before
* we continue.
*/
spin_lock_irq(&conf->resync_lock);
conf->barrier++;
conf->nr_waiting++;
wait_event_lock_irq(conf->wait_barrier,
conf->nr_pending == conf->nr_queued+1,
conf->resync_lock,
flush_pending_writes(conf));
spin_unlock_irq(&conf->resync_lock);
}
static void unfreeze_array(struct r10conf *conf)
{
/* reverse the effect of the freeze */
spin_lock_irq(&conf->resync_lock);
conf->barrier--;
conf->nr_waiting--;
wake_up(&conf->wait_barrier);
spin_unlock_irq(&conf->resync_lock);
}
static void make_request(struct mddev *mddev, struct bio * bio)
{
struct r10conf *conf = mddev->private;
struct r10bio *r10_bio;
struct bio *read_bio;
int i;
int chunk_sects = conf->chunk_mask + 1;
const int rw = bio_data_dir(bio);
const unsigned long do_sync = (bio->bi_rw & REQ_SYNC);
const unsigned long do_fua = (bio->bi_rw & REQ_FUA);
unsigned long flags;
struct md_rdev *blocked_rdev;
int plugged;
int sectors_handled;
int max_sectors;
if (unlikely(bio->bi_rw & REQ_FLUSH)) {
md_flush_request(mddev, bio);
return;
}
/* If this request crosses a chunk boundary, we need to
* split it. This will only happen for 1 PAGE (or less) requests.
*/
if (unlikely( (bio->bi_sector & conf->chunk_mask) + (bio->bi_size >> 9)
> chunk_sects &&
conf->near_copies < conf->raid_disks)) {
struct bio_pair *bp;
/* Sanity check -- queue functions should prevent this happening */
if (bio->bi_vcnt != 1 ||
bio->bi_idx != 0)
goto bad_map;
/* This is a one page bio that upper layers
* refuse to split for us, so we need to split it.
*/
bp = bio_split(bio,
chunk_sects - (bio->bi_sector & (chunk_sects - 1)) );
/* Each of these 'make_request' calls will call 'wait_barrier'.
* If the first succeeds but the second blocks due to the resync
* thread raising the barrier, we will deadlock because the
* IO to the underlying device will be queued in generic_make_request
* and will never complete, so will never reduce nr_pending.
* So increment nr_waiting here so no new raise_barriers will
* succeed, and so the second wait_barrier cannot block.
*/
spin_lock_irq(&conf->resync_lock);
conf->nr_waiting++;
spin_unlock_irq(&conf->resync_lock);
make_request(mddev, &bp->bio1);
make_request(mddev, &bp->bio2);
spin_lock_irq(&conf->resync_lock);
conf->nr_waiting--;
wake_up(&conf->wait_barrier);
spin_unlock_irq(&conf->resync_lock);
bio_pair_release(bp);
return;
bad_map:
printk("md/raid10:%s: make_request bug: can't convert block across chunks"
" or bigger than %dk %llu %d\n", mdname(mddev), chunk_sects/2,
(unsigned long long)bio->bi_sector, bio->bi_size >> 10);
bio_io_error(bio);
return;
}
md_write_start(mddev, bio);
/*
* Register the new request and wait if the reconstruction
* thread has put up a bar for new requests.
* Continue immediately if no resync is active currently.
*/
wait_barrier(conf);
r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO);
r10_bio->master_bio = bio;
r10_bio->sectors = bio->bi_size >> 9;
r10_bio->mddev = mddev;
r10_bio->sector = bio->bi_sector;
r10_bio->state = 0;
/* We might need to issue multiple reads to different
* devices if there are bad blocks around, so we keep
* track of the number of reads in bio->bi_phys_segments.
* If this is 0, there is only one r10_bio and no locking
* will be needed when the request completes. If it is
* non-zero, then it is the number of not-completed requests.
*/
bio->bi_phys_segments = 0;
clear_bit(BIO_SEG_VALID, &bio->bi_flags);
if (rw == READ) {
/*
* read balancing logic:
*/
struct md_rdev *rdev;
int slot;
read_again:
rdev = read_balance(conf, r10_bio, &max_sectors);
if (!rdev) {
raid_end_bio_io(r10_bio);
return;
}
slot = r10_bio->read_slot;
read_bio = bio_clone_mddev(bio, GFP_NOIO, mddev);
md_trim_bio(read_bio, r10_bio->sector - bio->bi_sector,
max_sectors);
r10_bio->devs[slot].bio = read_bio;
r10_bio->devs[slot].rdev = rdev;
read_bio->bi_sector = r10_bio->devs[slot].addr +
rdev->data_offset;
read_bio->bi_bdev = rdev->bdev;
read_bio->bi_end_io = raid10_end_read_request;
read_bio->bi_rw = READ | do_sync;
read_bio->bi_private = r10_bio;
if (max_sectors < r10_bio->sectors) {
/* Could not read all from this device, so we will
* need another r10_bio.
*/
sectors_handled = (r10_bio->sectors + max_sectors
- bio->bi_sector);
r10_bio->sectors = max_sectors;
spin_lock_irq(&conf->device_lock);
if (bio->bi_phys_segments == 0)
bio->bi_phys_segments = 2;
else
bio->bi_phys_segments++;
spin_unlock(&conf->device_lock);
/* Cannot call generic_make_request directly
* as that will be queued in __generic_make_request
* and subsequent mempool_alloc might block
* waiting for it. so hand bio over to raid10d.
*/
reschedule_retry(r10_bio);
r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO);
r10_bio->master_bio = bio;
r10_bio->sectors = ((bio->bi_size >> 9)
- sectors_handled);
r10_bio->state = 0;
r10_bio->mddev = mddev;
r10_bio->sector = bio->bi_sector + sectors_handled;
goto read_again;
} else
generic_make_request(read_bio);
return;
}
/*
* WRITE:
*/
if (conf->pending_count >= max_queued_requests) {
md_wakeup_thread(mddev->thread);
wait_event(conf->wait_barrier,
conf->pending_count < max_queued_requests);
}
/* first select target devices under rcu_lock and
* inc refcount on their rdev. Record them by setting
* bios[x] to bio
* If there are known/acknowledged bad blocks on any device
* on which we have seen a write error, we want to avoid
* writing to those blocks. This potentially requires several
* writes to write around the bad blocks. Each set of writes
* gets its own r10_bio with a set of bios attached. The number
* of r10_bios is recored in bio->bi_phys_segments just as with
* the read case.
*/
plugged = mddev_check_plugged(mddev);
r10_bio->read_slot = -1; /* make sure repl_bio gets freed */
raid10_find_phys(conf, r10_bio);
retry_write:
blocked_rdev = NULL;
rcu_read_lock();
max_sectors = r10_bio->sectors;
for (i = 0; i < conf->copies; i++) {
int d = r10_bio->devs[i].devnum;
struct md_rdev *rdev = rcu_dereference(conf->mirrors[d].rdev);
if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
atomic_inc(&rdev->nr_pending);
blocked_rdev = rdev;
break;
}
r10_bio->devs[i].bio = NULL;
if (!rdev || test_bit(Faulty, &rdev->flags)) {
set_bit(R10BIO_Degraded, &r10_bio->state);
continue;
}
if (test_bit(WriteErrorSeen, &rdev->flags)) {
sector_t first_bad;
sector_t dev_sector = r10_bio->devs[i].addr;
int bad_sectors;
int is_bad;
is_bad = is_badblock(rdev, dev_sector,
max_sectors,
&first_bad, &bad_sectors);
if (is_bad < 0) {
/* Mustn't write here until the bad block
* is acknowledged
*/
atomic_inc(&rdev->nr_pending);
set_bit(BlockedBadBlocks, &rdev->flags);
blocked_rdev = rdev;
break;
}
if (is_bad && first_bad <= dev_sector) {
/* Cannot write here at all */
bad_sectors -= (dev_sector - first_bad);
if (bad_sectors < max_sectors)
/* Mustn't write more than bad_sectors
* to other devices yet
*/
max_sectors = bad_sectors;
/* We don't set R10BIO_Degraded as that
* only applies if the disk is missing,
* so it might be re-added, and we want to
* know to recover this chunk.
* In this case the device is here, and the
* fact that this chunk is not in-sync is
* recorded in the bad block log.
*/
continue;
}
if (is_bad) {
int good_sectors = first_bad - dev_sector;
if (good_sectors < max_sectors)
max_sectors = good_sectors;
}
}
r10_bio->devs[i].bio = bio;
atomic_inc(&rdev->nr_pending);
}
rcu_read_unlock();
if (unlikely(blocked_rdev)) {
/* Have to wait for this device to get unblocked, then retry */
int j;
int d;
for (j = 0; j < i; j++)
if (r10_bio->devs[j].bio) {
d = r10_bio->devs[j].devnum;
rdev_dec_pending(conf->mirrors[d].rdev, mddev);
}
allow_barrier(conf);
md_wait_for_blocked_rdev(blocked_rdev, mddev);
wait_barrier(conf);
goto retry_write;
}
if (max_sectors < r10_bio->sectors) {
/* We are splitting this into multiple parts, so
* we need to prepare for allocating another r10_bio.
*/
r10_bio->sectors = max_sectors;
spin_lock_irq(&conf->device_lock);
if (bio->bi_phys_segments == 0)
bio->bi_phys_segments = 2;
else
bio->bi_phys_segments++;
spin_unlock_irq(&conf->device_lock);
}
sectors_handled = r10_bio->sector + max_sectors - bio->bi_sector;
atomic_set(&r10_bio->remaining, 1);
bitmap_startwrite(mddev->bitmap, r10_bio->sector, r10_bio->sectors, 0);
for (i = 0; i < conf->copies; i++) {
struct bio *mbio;
int d = r10_bio->devs[i].devnum;
if (!r10_bio->devs[i].bio)
continue;
mbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
md_trim_bio(mbio, r10_bio->sector - bio->bi_sector,
max_sectors);
r10_bio->devs[i].bio = mbio;
mbio->bi_sector = (r10_bio->devs[i].addr+
conf->mirrors[d].rdev->data_offset);
mbio->bi_bdev = conf->mirrors[d].rdev->bdev;
mbio->bi_end_io = raid10_end_write_request;
mbio->bi_rw = WRITE | do_sync | do_fua;
mbio->bi_private = r10_bio;
atomic_inc(&r10_bio->remaining);
spin_lock_irqsave(&conf->device_lock, flags);
bio_list_add(&conf->pending_bio_list, mbio);
conf->pending_count++;
spin_unlock_irqrestore(&conf->device_lock, flags);
}
/* Don't remove the bias on 'remaining' (one_write_done) until
* after checking if we need to go around again.
*/
if (sectors_handled < (bio->bi_size >> 9)) {
one_write_done(r10_bio);
/* We need another r10_bio. It has already been counted
* in bio->bi_phys_segments.
*/
r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO);
r10_bio->master_bio = bio;
r10_bio->sectors = (bio->bi_size >> 9) - sectors_handled;
r10_bio->mddev = mddev;
r10_bio->sector = bio->bi_sector + sectors_handled;
r10_bio->state = 0;
goto retry_write;
}
one_write_done(r10_bio);
/* In case raid10d snuck in to freeze_array */
wake_up(&conf->wait_barrier);
if (do_sync || !mddev->bitmap || !plugged)
md_wakeup_thread(mddev->thread);
}
static void status(struct seq_file *seq, struct mddev *mddev)
{
struct r10conf *conf = mddev->private;
int i;
if (conf->near_copies < conf->raid_disks)
seq_printf(seq, " %dK chunks", mddev->chunk_sectors / 2);
if (conf->near_copies > 1)
seq_printf(seq, " %d near-copies", conf->near_copies);
if (conf->far_copies > 1) {
if (conf->far_offset)
seq_printf(seq, " %d offset-copies", conf->far_copies);
else
seq_printf(seq, " %d far-copies", conf->far_copies);
}
seq_printf(seq, " [%d/%d] [", conf->raid_disks,
conf->raid_disks - mddev->degraded);
for (i = 0; i < conf->raid_disks; i++)
seq_printf(seq, "%s",
conf->mirrors[i].rdev &&
test_bit(In_sync, &conf->mirrors[i].rdev->flags) ? "U" : "_");
seq_printf(seq, "]");
}
/* check if there are enough drives for
* every block to appear on atleast one.
* Don't consider the device numbered 'ignore'
* as we might be about to remove it.
*/
static int enough(struct r10conf *conf, int ignore)
{
int first = 0;
do {
int n = conf->copies;
int cnt = 0;
while (n--) {
if (conf->mirrors[first].rdev &&
first != ignore)
cnt++;
first = (first+1) % conf->raid_disks;
}
if (cnt == 0)
return 0;
} while (first != 0);
return 1;
}
static void error(struct mddev *mddev, struct md_rdev *rdev)
{
char b[BDEVNAME_SIZE];
struct r10conf *conf = mddev->private;
/*
* If it is not operational, then we have already marked it as dead
* else if it is the last working disks, ignore the error, let the
* next level up know.
* else mark the drive as failed
*/
if (test_bit(In_sync, &rdev->flags)
&& !enough(conf, rdev->raid_disk))
/*
* Don't fail the drive, just return an IO error.
*/
return;
if (test_and_clear_bit(In_sync, &rdev->flags)) {
unsigned long flags;
spin_lock_irqsave(&conf->device_lock, flags);
mddev->degraded++;
spin_unlock_irqrestore(&conf->device_lock, flags);
/*
* if recovery is running, make sure it aborts.
*/
set_bit(MD_RECOVERY_INTR, &mddev->recovery);
}
set_bit(Blocked, &rdev->flags);
set_bit(Faulty, &rdev->flags);
set_bit(MD_CHANGE_DEVS, &mddev->flags);
printk(KERN_ALERT
"md/raid10:%s: Disk failure on %s, disabling device.\n"
"md/raid10:%s: Operation continuing on %d devices.\n",
mdname(mddev), bdevname(rdev->bdev, b),
mdname(mddev), conf->raid_disks - mddev->degraded);
}
static void print_conf(struct r10conf *conf)
{
int i;
struct mirror_info *tmp;
printk(KERN_DEBUG "RAID10 conf printout:\n");
if (!conf) {
printk(KERN_DEBUG "(!conf)\n");
return;
}
printk(KERN_DEBUG " --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
conf->raid_disks);
for (i = 0; i < conf->raid_disks; i++) {
char b[BDEVNAME_SIZE];
tmp = conf->mirrors + i;
if (tmp->rdev)
printk(KERN_DEBUG " disk %d, wo:%d, o:%d, dev:%s\n",
i, !test_bit(In_sync, &tmp->rdev->flags),
!test_bit(Faulty, &tmp->rdev->flags),
bdevname(tmp->rdev->bdev,b));
}
}
static void close_sync(struct r10conf *conf)
{
wait_barrier(conf);
allow_barrier(conf);
mempool_destroy(conf->r10buf_pool);
conf->r10buf_pool = NULL;
}
static int raid10_spare_active(struct mddev *mddev)
{
int i;
struct r10conf *conf = mddev->private;
struct mirror_info *tmp;
int count = 0;
unsigned long flags;
/*
* Find all non-in_sync disks within the RAID10 configuration
* and mark them in_sync
*/
for (i = 0; i < conf->raid_disks; i++) {
tmp = conf->mirrors + i;
if (tmp->rdev
&& !test_bit(Faulty, &tmp->rdev->flags)
&& !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
count++;
sysfs_notify_dirent(tmp->rdev->sysfs_state);
}
}
spin_lock_irqsave(&conf->device_lock, flags);
mddev->degraded -= count;
spin_unlock_irqrestore(&conf->device_lock, flags);
print_conf(conf);
return count;
}
static int raid10_add_disk(struct mddev *mddev, struct md_rdev *rdev)
{
struct r10conf *conf = mddev->private;
int err = -EEXIST;
int mirror;
int first = 0;
int last = conf->raid_disks - 1;
if (mddev->recovery_cp < MaxSector)
/* only hot-add to in-sync arrays, as recovery is
* very different from resync
*/
return -EBUSY;
if (!enough(conf, -1))
return -EINVAL;
if (rdev->raid_disk >= 0)
first = last = rdev->raid_disk;
if (rdev->saved_raid_disk >= first &&
conf->mirrors[rdev->saved_raid_disk].rdev == NULL)
mirror = rdev->saved_raid_disk;
else
mirror = first;
for ( ; mirror <= last ; mirror++) {
struct mirror_info *p = &conf->mirrors[mirror];
if (p->recovery_disabled == mddev->recovery_disabled)
continue;
if (p->rdev)
continue;
disk_stack_limits(mddev->gendisk, rdev->bdev,
rdev->data_offset << 9);
/* as we don't honour merge_bvec_fn, we must
* never risk violating it, so limit
* ->max_segments to one lying with a single
* page, as a one page request is never in
* violation.
*/
if (rdev->bdev->bd_disk->queue->merge_bvec_fn) {
blk_queue_max_segments(mddev->queue, 1);
blk_queue_segment_boundary(mddev->queue,
PAGE_CACHE_SIZE - 1);
}
p->head_position = 0;
p->recovery_disabled = mddev->recovery_disabled - 1;
rdev->raid_disk = mirror;
err = 0;
if (rdev->saved_raid_disk != mirror)
conf->fullsync = 1;
rcu_assign_pointer(p->rdev, rdev);
break;
}
md_integrity_add_rdev(rdev, mddev);
print_conf(conf);
return err;
}
static int raid10_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
{
struct r10conf *conf = mddev->private;
int err = 0;
int number = rdev->raid_disk;
struct mirror_info *p = conf->mirrors+ number;
print_conf(conf);
if (rdev == p->rdev) {
if (test_bit(In_sync, &rdev->flags) ||
atomic_read(&rdev->nr_pending)) {
err = -EBUSY;
goto abort;
}
/* Only remove faulty devices in recovery
* is not possible.
*/
if (!test_bit(Faulty, &rdev->flags) &&
mddev->recovery_disabled != p->recovery_disabled &&
enough(conf, -1)) {
err = -EBUSY;
goto abort;
}
p->rdev = NULL;
synchronize_rcu();
if (atomic_read(&rdev->nr_pending)) {
/* lost the race, try later */
err = -EBUSY;
p->rdev = rdev;
goto abort;
}
err = md_integrity_register(mddev);
}
abort:
print_conf(conf);
return err;
}
static void end_sync_read(struct bio *bio, int error)
{
struct r10bio *r10_bio = bio->bi_private;
struct r10conf *conf = r10_bio->mddev->private;
int d;
d = find_bio_disk(conf, r10_bio, bio, NULL, NULL);
if (test_bit(BIO_UPTODATE, &bio->bi_flags))
set_bit(R10BIO_Uptodate, &r10_bio->state);
else
/* The write handler will notice the lack of
* R10BIO_Uptodate and record any errors etc
*/
atomic_add(r10_bio->sectors,
&conf->mirrors[d].rdev->corrected_errors);
/* for reconstruct, we always reschedule after a read.
* for resync, only after all reads
*/
rdev_dec_pending(conf->mirrors[d].rdev, conf->mddev);
if (test_bit(R10BIO_IsRecover, &r10_bio->state) ||
atomic_dec_and_test(&r10_bio->remaining)) {
/* we have read all the blocks,
* do the comparison in process context in raid10d
*/
reschedule_retry(r10_bio);
}
}
static void end_sync_request(struct r10bio *r10_bio)
{
struct mddev *mddev = r10_bio->mddev;
while (atomic_dec_and_test(&r10_bio->remaining)) {
if (r10_bio->master_bio == NULL) {
/* the primary of several recovery bios */
sector_t s = r10_bio->sectors;
if (test_bit(R10BIO_MadeGood, &r10_bio->state) ||
test_bit(R10BIO_WriteError, &r10_bio->state))
reschedule_retry(r10_bio);
else
put_buf(r10_bio);
md_done_sync(mddev, s, 1);
break;
} else {
struct r10bio *r10_bio2 = (struct r10bio *)r10_bio->master_bio;
if (test_bit(R10BIO_MadeGood, &r10_bio->state) ||
test_bit(R10BIO_WriteError, &r10_bio->state))
reschedule_retry(r10_bio);
else
put_buf(r10_bio);
r10_bio = r10_bio2;
}
}
}
static void end_sync_write(struct bio *bio, int error)
{
int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
struct r10bio *r10_bio = bio->bi_private;
struct mddev *mddev = r10_bio->mddev;
struct r10conf *conf = mddev->private;
int d;
sector_t first_bad;
int bad_sectors;
int slot;
d = find_bio_disk(conf, r10_bio, bio, &slot, NULL);
if (!uptodate) {
set_bit(WriteErrorSeen, &conf->mirrors[d].rdev->flags);
set_bit(R10BIO_WriteError, &r10_bio->state);
} else if (is_badblock(conf->mirrors[d].rdev,
r10_bio->devs[slot].addr,
r10_bio->sectors,
&first_bad, &bad_sectors))
set_bit(R10BIO_MadeGood, &r10_bio->state);
rdev_dec_pending(conf->mirrors[d].rdev, mddev);
end_sync_request(r10_bio);
}
/*
* Note: sync and recover and handled very differently for raid10
* This code is for resync.
* For resync, we read through virtual addresses and read all blocks.
* If there is any error, we schedule a write. The lowest numbered
* drive is authoritative.
* However requests come for physical address, so we need to map.
* For every physical address there are raid_disks/copies virtual addresses,
* which is always are least one, but is not necessarly an integer.
* This means that a physical address can span multiple chunks, so we may
* have to submit multiple io requests for a single sync request.
*/
/*
* We check if all blocks are in-sync and only write to blocks that
* aren't in sync
*/
static void sync_request_write(struct mddev *mddev, struct r10bio *r10_bio)
{
struct r10conf *conf = mddev->private;
int i, first;
struct bio *tbio, *fbio;
atomic_set(&r10_bio->remaining, 1);
/* find the first device with a block */
for (i=0; i<conf->copies; i++)
if (test_bit(BIO_UPTODATE, &r10_bio->devs[i].bio->bi_flags))
break;
if (i == conf->copies)
goto done;
first = i;
fbio = r10_bio->devs[i].bio;
/* now find blocks with errors */
for (i=0 ; i < conf->copies ; i++) {
int j, d;
int vcnt = r10_bio->sectors >> (PAGE_SHIFT-9);
tbio = r10_bio->devs[i].bio;
if (tbio->bi_end_io != end_sync_read)
continue;
if (i == first)
continue;
if (test_bit(BIO_UPTODATE, &r10_bio->devs[i].bio->bi_flags)) {
/* We know that the bi_io_vec layout is the same for
* both 'first' and 'i', so we just compare them.
* All vec entries are PAGE_SIZE;
*/
for (j = 0; j < vcnt; j++)
if (memcmp(page_address(fbio->bi_io_vec[j].bv_page),
page_address(tbio->bi_io_vec[j].bv_page),
PAGE_SIZE))
break;
if (j == vcnt)
continue;
mddev->resync_mismatches += r10_bio->sectors;
if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
/* Don't fix anything. */
continue;
}
/* Ok, we need to write this bio, either to correct an
* inconsistency or to correct an unreadable block.
* First we need to fixup bv_offset, bv_len and
* bi_vecs, as the read request might have corrupted these
*/
tbio->bi_vcnt = vcnt;
tbio->bi_size = r10_bio->sectors << 9;
tbio->bi_idx = 0;
tbio->bi_phys_segments = 0;
tbio->bi_flags &= ~(BIO_POOL_MASK - 1);
tbio->bi_flags |= 1 << BIO_UPTODATE;
tbio->bi_next = NULL;
tbio->bi_rw = WRITE;
tbio->bi_private = r10_bio;
tbio->bi_sector = r10_bio->devs[i].addr;
for (j=0; j < vcnt ; j++) {
tbio->bi_io_vec[j].bv_offset = 0;
tbio->bi_io_vec[j].bv_len = PAGE_SIZE;
memcpy(page_address(tbio->bi_io_vec[j].bv_page),
page_address(fbio->bi_io_vec[j].bv_page),
PAGE_SIZE);
}
tbio->bi_end_io = end_sync_write;
d = r10_bio->devs[i].devnum;
atomic_inc(&conf->mirrors[d].rdev->nr_pending);
atomic_inc(&r10_bio->remaining);
md_sync_acct(conf->mirrors[d].rdev->bdev, tbio->bi_size >> 9);
tbio->bi_sector += conf->mirrors[d].rdev->data_offset;
tbio->bi_bdev = conf->mirrors[d].rdev->bdev;
generic_make_request(tbio);
}
done:
if (atomic_dec_and_test(&r10_bio->remaining)) {
md_done_sync(mddev, r10_bio->sectors, 1);
put_buf(r10_bio);
}
}
/*
* Now for the recovery code.
* Recovery happens across physical sectors.
* We recover all non-is_sync drives by finding the virtual address of
* each, and then choose a working drive that also has that virt address.
* There is a separate r10_bio for each non-in_sync drive.
* Only the first two slots are in use. The first for reading,
* The second for writing.
*
*/
static void fix_recovery_read_error(struct r10bio *r10_bio)
{
/* We got a read error during recovery.
* We repeat the read in smaller page-sized sections.
* If a read succeeds, write it to the new device or record
* a bad block if we cannot.
* If a read fails, record a bad block on both old and
* new devices.
*/
struct mddev *mddev = r10_bio->mddev;
struct r10conf *conf = mddev->private;
struct bio *bio = r10_bio->devs[0].bio;
sector_t sect = 0;
int sectors = r10_bio->sectors;
int idx = 0;
int dr = r10_bio->devs[0].devnum;
int dw = r10_bio->devs[1].devnum;
while (sectors) {
int s = sectors;
struct md_rdev *rdev;
sector_t addr;
int ok;
if (s > (PAGE_SIZE>>9))
s = PAGE_SIZE >> 9;
rdev = conf->mirrors[dr].rdev;
addr = r10_bio->devs[0].addr + sect,
ok = sync_page_io(rdev,
addr,
s << 9,
bio->bi_io_vec[idx].bv_page,
READ, false);
if (ok) {
rdev = conf->mirrors[dw].rdev;
addr = r10_bio->devs[1].addr + sect;
ok = sync_page_io(rdev,
addr,
s << 9,
bio->bi_io_vec[idx].bv_page,
WRITE, false);
if (!ok)
set_bit(WriteErrorSeen, &rdev->flags);
}
if (!ok) {
/* We don't worry if we cannot set a bad block -
* it really is bad so there is no loss in not
* recording it yet
*/
rdev_set_badblocks(rdev, addr, s, 0);
if (rdev != conf->mirrors[dw].rdev) {
/* need bad block on destination too */
struct md_rdev *rdev2 = conf->mirrors[dw].rdev;
addr = r10_bio->devs[1].addr + sect;
ok = rdev_set_badblocks(rdev2, addr, s, 0);
if (!ok) {
/* just abort the recovery */
printk(KERN_NOTICE
"md/raid10:%s: recovery aborted"
" due to read error\n",
mdname(mddev));
conf->mirrors[dw].recovery_disabled
= mddev->recovery_disabled;
set_bit(MD_RECOVERY_INTR,
&mddev->recovery);
break;
}
}
}
sectors -= s;
sect += s;
idx++;
}
}
static void recovery_request_write(struct mddev *mddev, struct r10bio *r10_bio)
{
struct r10conf *conf = mddev->private;
int d;
struct bio *wbio;
if (!test_bit(R10BIO_Uptodate, &r10_bio->state)) {
fix_recovery_read_error(r10_bio);
end_sync_request(r10_bio);
return;
}
/*
* share the pages with the first bio
* and submit the write request
*/
wbio = r10_bio->devs[1].bio;
d = r10_bio->devs[1].devnum;
atomic_inc(&conf->mirrors[d].rdev->nr_pending);
md_sync_acct(conf->mirrors[d].rdev->bdev, wbio->bi_size >> 9);
generic_make_request(wbio);
}
/*
* Used by fix_read_error() to decay the per rdev read_errors.
* We halve the read error count for every hour that has elapsed
* since the last recorded read error.
*
*/
static void check_decay_read_errors(struct mddev *mddev, struct md_rdev *rdev)
{
struct timespec cur_time_mon;
unsigned long hours_since_last;
unsigned int read_errors = atomic_read(&rdev->read_errors);
ktime_get_ts(&cur_time_mon);
if (rdev->last_read_error.tv_sec == 0 &&
rdev->last_read_error.tv_nsec == 0) {
/* first time we've seen a read error */
rdev->last_read_error = cur_time_mon;
return;
}
hours_since_last = (cur_time_mon.tv_sec -
rdev->last_read_error.tv_sec) / 3600;
rdev->last_read_error = cur_time_mon;
/*
* if hours_since_last is > the number of bits in read_errors
* just set read errors to 0. We do this to avoid
* overflowing the shift of read_errors by hours_since_last.
*/
if (hours_since_last >= 8 * sizeof(read_errors))
atomic_set(&rdev->read_errors, 0);
else
atomic_set(&rdev->read_errors, read_errors >> hours_since_last);
}
static int r10_sync_page_io(struct md_rdev *rdev, sector_t sector,
int sectors, struct page *page, int rw)
{
sector_t first_bad;
int bad_sectors;
if (is_badblock(rdev, sector, sectors, &first_bad, &bad_sectors)
&& (rw == READ || test_bit(WriteErrorSeen, &rdev->flags)))
return -1;
if (sync_page_io(rdev, sector, sectors << 9, page, rw, false))
/* success */
return 1;
if (rw == WRITE)
set_bit(WriteErrorSeen, &rdev->flags);
/* need to record an error - either for the block or the device */
if (!rdev_set_badblocks(rdev, sector, sectors, 0))
md_error(rdev->mddev, rdev);
return 0;
}
/*
* This is a kernel thread which:
*
* 1. Retries failed read operations on working mirrors.
* 2. Updates the raid superblock when problems encounter.
* 3. Performs writes following reads for array synchronising.
*/
static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10bio *r10_bio)
{
int sect = 0; /* Offset from r10_bio->sector */
int sectors = r10_bio->sectors;
struct md_rdev*rdev;
int max_read_errors = atomic_read(&mddev->max_corr_read_errors);
int d = r10_bio->devs[r10_bio->read_slot].devnum;
/* still own a reference to this rdev, so it cannot
* have been cleared recently.
*/
rdev = conf->mirrors[d].rdev;
if (test_bit(Faulty, &rdev->flags))
/* drive has already been failed, just ignore any
more fix_read_error() attempts */
return;
check_decay_read_errors(mddev, rdev);
atomic_inc(&rdev->read_errors);
if (atomic_read(&rdev->read_errors) > max_read_errors) {
char b[BDEVNAME_SIZE];
bdevname(rdev->bdev, b);
printk(KERN_NOTICE
"md/raid10:%s: %s: Raid device exceeded "
"read_error threshold [cur %d:max %d]\n",
mdname(mddev), b,
atomic_read(&rdev->read_errors), max_read_errors);
printk(KERN_NOTICE
"md/raid10:%s: %s: Failing raid device\n",
mdname(mddev), b);
md_error(mddev, conf->mirrors[d].rdev);
return;
}
while(sectors) {
int s = sectors;
int sl = r10_bio->read_slot;
int success = 0;
int start;
if (s > (PAGE_SIZE>>9))
s = PAGE_SIZE >> 9;
rcu_read_lock();
do {
sector_t first_bad;
int bad_sectors;
d = r10_bio->devs[sl].devnum;
rdev = rcu_dereference(conf->mirrors[d].rdev);
if (rdev &&
test_bit(In_sync, &rdev->flags) &&
is_badblock(rdev, r10_bio->devs[sl].addr + sect, s,
&first_bad, &bad_sectors) == 0) {
atomic_inc(&rdev->nr_pending);
rcu_read_unlock();
success = sync_page_io(rdev,
r10_bio->devs[sl].addr +
sect,
s<<9,
conf->tmppage, READ, false);
rdev_dec_pending(rdev, mddev);
rcu_read_lock();
if (success)
break;
}
sl++;
if (sl == conf->copies)
sl = 0;
} while (!success && sl != r10_bio->read_slot);
rcu_read_unlock();
if (!success) {
/* Cannot read from anywhere, just mark the block
* as bad on the first device to discourage future
* reads.
*/
int dn = r10_bio->devs[r10_bio->read_slot].devnum;
rdev = conf->mirrors[dn].rdev;
if (!rdev_set_badblocks(
rdev,
r10_bio->devs[r10_bio->read_slot].addr
+ sect,
s, 0))
md_error(mddev, rdev);
break;
}
start = sl;
/* write it back and re-read */
rcu_read_lock();
while (sl != r10_bio->read_slot) {
char b[BDEVNAME_SIZE];
if (sl==0)
sl = conf->copies;
sl--;
d = r10_bio->devs[sl].devnum;
rdev = rcu_dereference(conf->mirrors[d].rdev);
if (!rdev ||
!test_bit(In_sync, &rdev->flags))
continue;
atomic_inc(&rdev->nr_pending);
rcu_read_unlock();
if (r10_sync_page_io(rdev,
r10_bio->devs[sl].addr +
sect,
s<<9, conf->tmppage, WRITE)
== 0) {
/* Well, this device is dead */
printk(KERN_NOTICE
"md/raid10:%s: read correction "
"write failed"
" (%d sectors at %llu on %s)\n",
mdname(mddev), s,
(unsigned long long)(
sect + rdev->data_offset),
bdevname(rdev->bdev, b));
printk(KERN_NOTICE "md/raid10:%s: %s: failing "
"drive\n",
mdname(mddev),
bdevname(rdev->bdev, b));
}
rdev_dec_pending(rdev, mddev);
rcu_read_lock();
}
sl = start;
while (sl != r10_bio->read_slot) {
char b[BDEVNAME_SIZE];
if (sl==0)
sl = conf->copies;
sl--;
d = r10_bio->devs[sl].devnum;
rdev = rcu_dereference(conf->mirrors[d].rdev);
if (!rdev ||
!test_bit(In_sync, &rdev->flags))
continue;
atomic_inc(&rdev->nr_pending);
rcu_read_unlock();
switch (r10_sync_page_io(rdev,
r10_bio->devs[sl].addr +
sect,
s<<9, conf->tmppage,
READ)) {
case 0:
/* Well, this device is dead */
printk(KERN_NOTICE
"md/raid10:%s: unable to read back "
"corrected sectors"
" (%d sectors at %llu on %s)\n",
mdname(mddev), s,
(unsigned long long)(
sect + rdev->data_offset),
bdevname(rdev->bdev, b));
printk(KERN_NOTICE "md/raid10:%s: %s: failing "
"drive\n",
mdname(mddev),
bdevname(rdev->bdev, b));
break;
case 1:
printk(KERN_INFO
"md/raid10:%s: read error corrected"
" (%d sectors at %llu on %s)\n",
mdname(mddev), s,
(unsigned long long)(
sect + rdev->data_offset),
bdevname(rdev->bdev, b));
atomic_add(s, &rdev->corrected_errors);
}
rdev_dec_pending(rdev, mddev);
rcu_read_lock();
}
rcu_read_unlock();
sectors -= s;
sect += s;
}
}
static void bi_complete(struct bio *bio, int error)
{
complete((struct completion *)bio->bi_private);
}
static int submit_bio_wait(int rw, struct bio *bio)
{
struct completion event;
rw |= REQ_SYNC;
init_completion(&event);
bio->bi_private = &event;
bio->bi_end_io = bi_complete;
submit_bio(rw, bio);
wait_for_completion(&event);
return test_bit(BIO_UPTODATE, &bio->bi_flags);
}
static int narrow_write_error(struct r10bio *r10_bio, int i)
{
struct bio *bio = r10_bio->master_bio;
struct mddev *mddev = r10_bio->mddev;
struct r10conf *conf = mddev->private;
struct md_rdev *rdev = conf->mirrors[r10_bio->devs[i].devnum].rdev;
/* bio has the data to be written to slot 'i' where
* we just recently had a write error.
* We repeatedly clone the bio and trim down to one block,
* then try the write. Where the write fails we record
* a bad block.
* It is conceivable that the bio doesn't exactly align with
* blocks. We must handle this.
*
* We currently own a reference to the rdev.
*/
int block_sectors;
sector_t sector;
int sectors;
int sect_to_write = r10_bio->sectors;
int ok = 1;
if (rdev->badblocks.shift < 0)
return 0;
block_sectors = 1 << rdev->badblocks.shift;
sector = r10_bio->sector;
sectors = ((r10_bio->sector + block_sectors)
& ~(sector_t)(block_sectors - 1))
- sector;
while (sect_to_write) {
struct bio *wbio;
if (sectors > sect_to_write)
sectors = sect_to_write;
/* Write at 'sector' for 'sectors' */
wbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
md_trim_bio(wbio, sector - bio->bi_sector, sectors);
wbio->bi_sector = (r10_bio->devs[i].addr+
rdev->data_offset+
(sector - r10_bio->sector));
wbio->bi_bdev = rdev->bdev;
if (submit_bio_wait(WRITE, wbio) == 0)
/* Failure! */
ok = rdev_set_badblocks(rdev, sector,
sectors, 0)
&& ok;
bio_put(wbio);
sect_to_write -= sectors;
sector += sectors;
sectors = block_sectors;
}
return ok;
}
static void handle_read_error(struct mddev *mddev, struct r10bio *r10_bio)
{
int slot = r10_bio->read_slot;
struct bio *bio;
struct r10conf *conf = mddev->private;
struct md_rdev *rdev = r10_bio->devs[slot].rdev;
char b[BDEVNAME_SIZE];
unsigned long do_sync;
int max_sectors;
/* we got a read error. Maybe the drive is bad. Maybe just
* the block and we can fix it.
* We freeze all other IO, and try reading the block from
* other devices. When we find one, we re-write
* and check it that fixes the read error.
* This is all done synchronously while the array is
* frozen.
*/
if (mddev->ro == 0) {
freeze_array(conf);
fix_read_error(conf, mddev, r10_bio);
unfreeze_array(conf);
}
rdev_dec_pending(rdev, mddev);
bio = r10_bio->devs[slot].bio;
bdevname(bio->bi_bdev, b);
r10_bio->devs[slot].bio =
mddev->ro ? IO_BLOCKED : NULL;
read_more:
rdev = read_balance(conf, r10_bio, &max_sectors);
if (rdev == NULL) {
printk(KERN_ALERT "md/raid10:%s: %s: unrecoverable I/O"
" read error for block %llu\n",
mdname(mddev), b,
(unsigned long long)r10_bio->sector);
raid_end_bio_io(r10_bio);
bio_put(bio);
return;
}
do_sync = (r10_bio->master_bio->bi_rw & REQ_SYNC);
if (bio)
bio_put(bio);
slot = r10_bio->read_slot;
printk_ratelimited(
KERN_ERR
"md/raid10:%s: %s: redirecting"
"sector %llu to another mirror\n",
mdname(mddev),
bdevname(rdev->bdev, b),
(unsigned long long)r10_bio->sector);
bio = bio_clone_mddev(r10_bio->master_bio,
GFP_NOIO, mddev);
md_trim_bio(bio,
r10_bio->sector - bio->bi_sector,
max_sectors);
r10_bio->devs[slot].bio = bio;
r10_bio->devs[slot].rdev = rdev;
bio->bi_sector = r10_bio->devs[slot].addr
+ rdev->data_offset;
bio->bi_bdev = rdev->bdev;
bio->bi_rw = READ | do_sync;
bio->bi_private = r10_bio;
bio->bi_end_io = raid10_end_read_request;
if (max_sectors < r10_bio->sectors) {
/* Drat - have to split this up more */
struct bio *mbio = r10_bio->master_bio;
int sectors_handled =
r10_bio->sector + max_sectors
- mbio->bi_sector;
r10_bio->sectors = max_sectors;
spin_lock_irq(&conf->device_lock);
if (mbio->bi_phys_segments == 0)
mbio->bi_phys_segments = 2;
else
mbio->bi_phys_segments++;
spin_unlock_irq(&conf->device_lock);
generic_make_request(bio);
bio = NULL;
r10_bio = mempool_alloc(conf->r10bio_pool,
GFP_NOIO);
r10_bio->master_bio = mbio;
r10_bio->sectors = (mbio->bi_size >> 9)
- sectors_handled;
r10_bio->state = 0;
set_bit(R10BIO_ReadError,
&r10_bio->state);
r10_bio->mddev = mddev;
r10_bio->sector = mbio->bi_sector
+ sectors_handled;
goto read_more;
} else
generic_make_request(bio);
}
static void handle_write_completed(struct r10conf *conf, struct r10bio *r10_bio)
{
/* Some sort of write request has finished and it
* succeeded in writing where we thought there was a
* bad block. So forget the bad block.
* Or possibly if failed and we need to record
* a bad block.
*/
int m;
struct md_rdev *rdev;
if (test_bit(R10BIO_IsSync, &r10_bio->state) ||
test_bit(R10BIO_IsRecover, &r10_bio->state)) {
for (m = 0; m < conf->copies; m++) {
int dev = r10_bio->devs[m].devnum;
rdev = conf->mirrors[dev].rdev;
if (r10_bio->devs[m].bio == NULL)
continue;
if (test_bit(BIO_UPTODATE,
&r10_bio->devs[m].bio->bi_flags)) {
rdev_clear_badblocks(
rdev,
r10_bio->devs[m].addr,
r10_bio->sectors);
} else {
if (!rdev_set_badblocks(
rdev,
r10_bio->devs[m].addr,
r10_bio->sectors, 0))
md_error(conf->mddev, rdev);
}
}
put_buf(r10_bio);
} else {
for (m = 0; m < conf->copies; m++) {
int dev = r10_bio->devs[m].devnum;
struct bio *bio = r10_bio->devs[m].bio;
rdev = conf->mirrors[dev].rdev;
if (bio == IO_MADE_GOOD) {
rdev_clear_badblocks(
rdev,
r10_bio->devs[m].addr,
r10_bio->sectors);
rdev_dec_pending(rdev, conf->mddev);
} else if (bio != NULL &&
!test_bit(BIO_UPTODATE, &bio->bi_flags)) {
if (!narrow_write_error(r10_bio, m)) {
md_error(conf->mddev, rdev);
set_bit(R10BIO_Degraded,
&r10_bio->state);
}
rdev_dec_pending(rdev, conf->mddev);
}
}
if (test_bit(R10BIO_WriteError,
&r10_bio->state))
close_write(r10_bio);
raid_end_bio_io(r10_bio);
}
}
static void raid10d(struct mddev *mddev)
{
struct r10bio *r10_bio;
unsigned long flags;
struct r10conf *conf = mddev->private;
struct list_head *head = &conf->retry_list;
struct blk_plug plug;
md_check_recovery(mddev);
blk_start_plug(&plug);
for (;;) {
flush_pending_writes(conf);
spin_lock_irqsave(&conf->device_lock, flags);
if (list_empty(head)) {
spin_unlock_irqrestore(&conf->device_lock, flags);
break;
}
r10_bio = list_entry(head->prev, struct r10bio, retry_list);
list_del(head->prev);
conf->nr_queued--;
spin_unlock_irqrestore(&conf->device_lock, flags);
mddev = r10_bio->mddev;
conf = mddev->private;
if (test_bit(R10BIO_MadeGood, &r10_bio->state) ||
test_bit(R10BIO_WriteError, &r10_bio->state))
handle_write_completed(conf, r10_bio);
else if (test_bit(R10BIO_IsSync, &r10_bio->state))
sync_request_write(mddev, r10_bio);
else if (test_bit(R10BIO_IsRecover, &r10_bio->state))
recovery_request_write(mddev, r10_bio);
else if (test_bit(R10BIO_ReadError, &r10_bio->state))
handle_read_error(mddev, r10_bio);
else {
/* just a partial read to be scheduled from a
* separate context
*/
int slot = r10_bio->read_slot;
generic_make_request(r10_bio->devs[slot].bio);
}
cond_resched();
if (mddev->flags & ~(1<<MD_CHANGE_PENDING))
md_check_recovery(mddev);
}
blk_finish_plug(&plug);
}
static int init_resync(struct r10conf *conf)
{
int buffs;
int i;
buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
BUG_ON(conf->r10buf_pool);
conf->have_replacement = 0;
for (i = 0; i < conf->raid_disks; i++)
if (conf->mirrors[i].replacement)
conf->have_replacement = 1;
conf->r10buf_pool = mempool_create(buffs, r10buf_pool_alloc, r10buf_pool_free, conf);
if (!conf->r10buf_pool)
return -ENOMEM;
conf->next_resync = 0;
return 0;
}
/*
* perform a "sync" on one "block"
*
* We need to make sure that no normal I/O request - particularly write
* requests - conflict with active sync requests.
*
* This is achieved by tracking pending requests and a 'barrier' concept
* that can be installed to exclude normal IO requests.
*
* Resync and recovery are handled very differently.
* We differentiate by looking at MD_RECOVERY_SYNC in mddev->recovery.
*
* For resync, we iterate over virtual addresses, read all copies,
* and update if there are differences. If only one copy is live,
* skip it.
* For recovery, we iterate over physical addresses, read a good
* value for each non-in_sync drive, and over-write.
*
* So, for recovery we may have several outstanding complex requests for a
* given address, one for each out-of-sync device. We model this by allocating
* a number of r10_bio structures, one for each out-of-sync device.
* As we setup these structures, we collect all bio's together into a list
* which we then process collectively to add pages, and then process again
* to pass to generic_make_request.
*
* The r10_bio structures are linked using a borrowed master_bio pointer.
* This link is counted in ->remaining. When the r10_bio that points to NULL
* has its remaining count decremented to 0, the whole complex operation
* is complete.
*
*/
static sector_t sync_request(struct mddev *mddev, sector_t sector_nr,
int *skipped, int go_faster)
{
struct r10conf *conf = mddev->private;
struct r10bio *r10_bio;
struct bio *biolist = NULL, *bio;
sector_t max_sector, nr_sectors;
int i;
int max_sync;
sector_t sync_blocks;
sector_t sectors_skipped = 0;
int chunks_skipped = 0;
if (!conf->r10buf_pool)
if (init_resync(conf))
return 0;
skipped:
max_sector = mddev->dev_sectors;
if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
max_sector = mddev->resync_max_sectors;
if (sector_nr >= max_sector) {
/* If we aborted, we need to abort the
* sync on the 'current' bitmap chucks (there can
* be several when recovering multiple devices).
* as we may have started syncing it but not finished.
* We can find the current address in
* mddev->curr_resync, but for recovery,
* we need to convert that to several
* virtual addresses.
*/
if (mddev->curr_resync < max_sector) { /* aborted */
if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
&sync_blocks, 1);
else for (i=0; i<conf->raid_disks; i++) {
sector_t sect =
raid10_find_virt(conf, mddev->curr_resync, i);
bitmap_end_sync(mddev->bitmap, sect,
&sync_blocks, 1);
}
} else /* completed sync */
conf->fullsync = 0;
bitmap_close_sync(mddev->bitmap);
close_sync(conf);
*skipped = 1;
return sectors_skipped;
}
if (chunks_skipped >= conf->raid_disks) {
/* if there has been nothing to do on any drive,
* then there is nothing to do at all..
*/
*skipped = 1;
return (max_sector - sector_nr) + sectors_skipped;
}
if (max_sector > mddev->resync_max)
max_sector = mddev->resync_max; /* Don't do IO beyond here */
/* make sure whole request will fit in a chunk - if chunks
* are meaningful
*/
if (conf->near_copies < conf->raid_disks &&
max_sector > (sector_nr | conf->chunk_mask))
max_sector = (sector_nr | conf->chunk_mask) + 1;
/*
* If there is non-resync activity waiting for us then
* put in a delay to throttle resync.
*/
if (!go_faster && conf->nr_waiting)
msleep_interruptible(1000);
/* Again, very different code for resync and recovery.
* Both must result in an r10bio with a list of bios that
* have bi_end_io, bi_sector, bi_bdev set,
* and bi_private set to the r10bio.
* For recovery, we may actually create several r10bios
* with 2 bios in each, that correspond to the bios in the main one.
* In this case, the subordinate r10bios link back through a
* borrowed master_bio pointer, and the counter in the master
* includes a ref from each subordinate.
*/
/* First, we decide what to do and set ->bi_end_io
* To end_sync_read if we want to read, and
* end_sync_write if we will want to write.
*/
max_sync = RESYNC_PAGES << (PAGE_SHIFT-9);
if (!test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
/* recovery... the complicated one */
int j;
r10_bio = NULL;
for (i=0 ; i<conf->raid_disks; i++) {
int still_degraded;
struct r10bio *rb2;
sector_t sect;
int must_sync;
int any_working;
if (conf->mirrors[i].rdev == NULL ||
test_bit(In_sync, &conf->mirrors[i].rdev->flags))
continue;
still_degraded = 0;
/* want to reconstruct this device */
rb2 = r10_bio;
sect = raid10_find_virt(conf, sector_nr, i);
/* Unless we are doing a full sync, we only need
* to recover the block if it is set in the bitmap
*/
must_sync = bitmap_start_sync(mddev->bitmap, sect,
&sync_blocks, 1);
if (sync_blocks < max_sync)
max_sync = sync_blocks;
if (!must_sync &&
!conf->fullsync) {
/* yep, skip the sync_blocks here, but don't assume
* that there will never be anything to do here
*/
chunks_skipped = -1;
continue;
}
r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO);
raise_barrier(conf, rb2 != NULL);
atomic_set(&r10_bio->remaining, 0);
r10_bio->master_bio = (struct bio*)rb2;
if (rb2)
atomic_inc(&rb2->remaining);
r10_bio->mddev = mddev;
set_bit(R10BIO_IsRecover, &r10_bio->state);
r10_bio->sector = sect;
raid10_find_phys(conf, r10_bio);
/* Need to check if the array will still be
* degraded
*/
for (j=0; j<conf->raid_disks; j++)
if (conf->mirrors[j].rdev == NULL ||
test_bit(Faulty, &conf->mirrors[j].rdev->flags)) {
still_degraded = 1;
break;
}
must_sync = bitmap_start_sync(mddev->bitmap, sect,
&sync_blocks, still_degraded);
any_working = 0;
for (j=0; j<conf->copies;j++) {
int k;
int d = r10_bio->devs[j].devnum;
sector_t from_addr, to_addr;
struct md_rdev *rdev;
sector_t sector, first_bad;
int bad_sectors;
if (!conf->mirrors[d].rdev ||
!test_bit(In_sync, &conf->mirrors[d].rdev->flags))
continue;
/* This is where we read from */
any_working = 1;
rdev = conf->mirrors[d].rdev;
sector = r10_bio->devs[j].addr;
if (is_badblock(rdev, sector, max_sync,
&first_bad, &bad_sectors)) {
if (first_bad > sector)
max_sync = first_bad - sector;
else {
bad_sectors -= (sector
- first_bad);
if (max_sync > bad_sectors)
max_sync = bad_sectors;
continue;
}
}
bio = r10_bio->devs[0].bio;
bio->bi_next = biolist;
biolist = bio;
bio->bi_private = r10_bio;
bio->bi_end_io = end_sync_read;
bio->bi_rw = READ;
from_addr = r10_bio->devs[j].addr;
bio->bi_sector = from_addr +
conf->mirrors[d].rdev->data_offset;
bio->bi_bdev = conf->mirrors[d].rdev->bdev;
atomic_inc(&conf->mirrors[d].rdev->nr_pending);
atomic_inc(&r10_bio->remaining);
/* and we write to 'i' */
for (k=0; k<conf->copies; k++)
if (r10_bio->devs[k].devnum == i)
break;
BUG_ON(k == conf->copies);
bio = r10_bio->devs[1].bio;
bio->bi_next = biolist;
biolist = bio;
bio->bi_private = r10_bio;
bio->bi_end_io = end_sync_write;
bio->bi_rw = WRITE;
to_addr = r10_bio->devs[k].addr;
bio->bi_sector = to_addr +
conf->mirrors[i].rdev->data_offset;
bio->bi_bdev = conf->mirrors[i].rdev->bdev;
r10_bio->devs[0].devnum = d;
r10_bio->devs[0].addr = from_addr;
r10_bio->devs[1].devnum = i;
r10_bio->devs[1].addr = to_addr;
break;
}
if (j == conf->copies) {
/* Cannot recover, so abort the recovery or
* record a bad block */
put_buf(r10_bio);
if (rb2)
atomic_dec(&rb2->remaining);
r10_bio = rb2;
if (any_working) {
/* problem is that there are bad blocks
* on other device(s)
*/
int k;
for (k = 0; k < conf->copies; k++)
if (r10_bio->devs[k].devnum == i)
break;
if (!rdev_set_badblocks(
conf->mirrors[i].rdev,
r10_bio->devs[k].addr,
max_sync, 0))
any_working = 0;
}
if (!any_working) {
if (!test_and_set_bit(MD_RECOVERY_INTR,
&mddev->recovery))
printk(KERN_INFO "md/raid10:%s: insufficient "
"working devices for recovery.\n",
mdname(mddev));
conf->mirrors[i].recovery_disabled
= mddev->recovery_disabled;
}
break;
}
}
if (biolist == NULL) {
while (r10_bio) {
struct r10bio *rb2 = r10_bio;
r10_bio = (struct r10bio*) rb2->master_bio;
rb2->master_bio = NULL;
put_buf(rb2);
}
goto giveup;
}
} else {
/* resync. Schedule a read for every block at this virt offset */
int count = 0;
bitmap_cond_end_sync(mddev->bitmap, sector_nr);
if (!bitmap_start_sync(mddev->bitmap, sector_nr,
&sync_blocks, mddev->degraded) &&
!conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED,
&mddev->recovery)) {
/* We can skip this block */
*skipped = 1;
return sync_blocks + sectors_skipped;
}
if (sync_blocks < max_sync)
max_sync = sync_blocks;
r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO);
r10_bio->mddev = mddev;
atomic_set(&r10_bio->remaining, 0);
raise_barrier(conf, 0);
conf->next_resync = sector_nr;
r10_bio->master_bio = NULL;
r10_bio->sector = sector_nr;
set_bit(R10BIO_IsSync, &r10_bio->state);
raid10_find_phys(conf, r10_bio);
r10_bio->sectors = (sector_nr | conf->chunk_mask) - sector_nr +1;
for (i=0; i<conf->copies; i++) {
int d = r10_bio->devs[i].devnum;
sector_t first_bad, sector;
int bad_sectors;
bio = r10_bio->devs[i].bio;
bio->bi_end_io = NULL;
clear_bit(BIO_UPTODATE, &bio->bi_flags);
if (conf->mirrors[d].rdev == NULL ||
test_bit(Faulty, &conf->mirrors[d].rdev->flags))
continue;
sector = r10_bio->devs[i].addr;
if (is_badblock(conf->mirrors[d].rdev,
sector, max_sync,
&first_bad, &bad_sectors)) {
if (first_bad > sector)
max_sync = first_bad - sector;
else {
bad_sectors -= (sector - first_bad);
if (max_sync > bad_sectors)
max_sync = max_sync;
continue;
}
}
atomic_inc(&conf->mirrors[d].rdev->nr_pending);
atomic_inc(&r10_bio->remaining);
bio->bi_next = biolist;
biolist = bio;
bio->bi_private = r10_bio;
bio->bi_end_io = end_sync_read;
bio->bi_rw = READ;
bio->bi_sector = sector +
conf->mirrors[d].rdev->data_offset;
bio->bi_bdev = conf->mirrors[d].rdev->bdev;
count++;
}
if (count < 2) {
for (i=0; i<conf->copies; i++) {
int d = r10_bio->devs[i].devnum;
if (r10_bio->devs[i].bio->bi_end_io)
rdev_dec_pending(conf->mirrors[d].rdev,
mddev);
}
put_buf(r10_bio);
biolist = NULL;
goto giveup;
}
}
for (bio = biolist; bio ; bio=bio->bi_next) {
bio->bi_flags &= ~(BIO_POOL_MASK - 1);
if (bio->bi_end_io)
bio->bi_flags |= 1 << BIO_UPTODATE;
bio->bi_vcnt = 0;
bio->bi_idx = 0;
bio->bi_phys_segments = 0;
bio->bi_size = 0;
}
nr_sectors = 0;
if (sector_nr + max_sync < max_sector)
max_sector = sector_nr + max_sync;
do {
struct page *page;
int len = PAGE_SIZE;
if (sector_nr + (len>>9) > max_sector)
len = (max_sector - sector_nr) << 9;
if (len == 0)
break;
for (bio= biolist ; bio ; bio=bio->bi_next) {
struct bio *bio2;
page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
if (bio_add_page(bio, page, len, 0))
continue;
/* stop here */
bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
for (bio2 = biolist;
bio2 && bio2 != bio;
bio2 = bio2->bi_next) {
/* remove last page from this bio */
bio2->bi_vcnt--;
bio2->bi_size -= len;
bio2->bi_flags &= ~(1<< BIO_SEG_VALID);
}
goto bio_full;
}
nr_sectors += len>>9;
sector_nr += len>>9;
} while (biolist->bi_vcnt < RESYNC_PAGES);
bio_full:
r10_bio->sectors = nr_sectors;
while (biolist) {
bio = biolist;
biolist = biolist->bi_next;
bio->bi_next = NULL;
r10_bio = bio->bi_private;
r10_bio->sectors = nr_sectors;
if (bio->bi_end_io == end_sync_read) {
md_sync_acct(bio->bi_bdev, nr_sectors);
generic_make_request(bio);
}
}
if (sectors_skipped)
/* pretend they weren't skipped, it makes
* no important difference in this case
*/
md_done_sync(mddev, sectors_skipped, 1);
return sectors_skipped + nr_sectors;
giveup:
/* There is nowhere to write, so all non-sync
* drives must be failed or in resync, all drives
* have a bad block, so try the next chunk...
*/
if (sector_nr + max_sync < max_sector)
max_sector = sector_nr + max_sync;
sectors_skipped += (max_sector - sector_nr);
chunks_skipped ++;
sector_nr = max_sector;
goto skipped;
}
static sector_t
raid10_size(struct mddev *mddev, sector_t sectors, int raid_disks)
{
sector_t size;
struct r10conf *conf = mddev->private;
if (!raid_disks)
raid_disks = conf->raid_disks;
if (!sectors)
sectors = conf->dev_sectors;
size = sectors >> conf->chunk_shift;
sector_div(size, conf->far_copies);
size = size * raid_disks;
sector_div(size, conf->near_copies);
return size << conf->chunk_shift;
}
static struct r10conf *setup_conf(struct mddev *mddev)
{
struct r10conf *conf = NULL;
int nc, fc, fo;
sector_t stride, size;
int err = -EINVAL;
if (mddev->new_chunk_sectors < (PAGE_SIZE >> 9) ||
!is_power_of_2(mddev->new_chunk_sectors)) {
printk(KERN_ERR "md/raid10:%s: chunk size must be "
"at least PAGE_SIZE(%ld) and be a power of 2.\n",
mdname(mddev), PAGE_SIZE);
goto out;
}
nc = mddev->new_layout & 255;
fc = (mddev->new_layout >> 8) & 255;
fo = mddev->new_layout & (1<<16);
if ((nc*fc) <2 || (nc*fc) > mddev->raid_disks ||
(mddev->new_layout >> 17)) {
printk(KERN_ERR "md/raid10:%s: unsupported raid10 layout: 0x%8x\n",
mdname(mddev), mddev->new_layout);
goto out;
}
err = -ENOMEM;
conf = kzalloc(sizeof(struct r10conf), GFP_KERNEL);
if (!conf)
goto out;
conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks,
GFP_KERNEL);
if (!conf->mirrors)
goto out;
conf->tmppage = alloc_page(GFP_KERNEL);
if (!conf->tmppage)
goto out;
conf->raid_disks = mddev->raid_disks;
conf->near_copies = nc;
conf->far_copies = fc;
conf->copies = nc*fc;
conf->far_offset = fo;
conf->chunk_mask = mddev->new_chunk_sectors - 1;
conf->chunk_shift = ffz(~mddev->new_chunk_sectors);
conf->r10bio_pool = mempool_create(NR_RAID10_BIOS, r10bio_pool_alloc,
r10bio_pool_free, conf);
if (!conf->r10bio_pool)
goto out;
size = mddev->dev_sectors >> conf->chunk_shift;
sector_div(size, fc);
size = size * conf->raid_disks;
sector_div(size, nc);
/* 'size' is now the number of chunks in the array */
/* calculate "used chunks per device" in 'stride' */
stride = size * conf->copies;
/* We need to round up when dividing by raid_disks to
* get the stride size.
*/
stride += conf->raid_disks - 1;
sector_div(stride, conf->raid_disks);
conf->dev_sectors = stride << conf->chunk_shift;
if (fo)
stride = 1;
else
sector_div(stride, fc);
conf->stride = stride << conf->chunk_shift;
spin_lock_init(&conf->device_lock);
INIT_LIST_HEAD(&conf->retry_list);
spin_lock_init(&conf->resync_lock);
init_waitqueue_head(&conf->wait_barrier);
conf->thread = md_register_thread(raid10d, mddev, NULL);
if (!conf->thread)
goto out;
conf->mddev = mddev;
return conf;
out:
printk(KERN_ERR "md/raid10:%s: couldn't allocate memory.\n",
mdname(mddev));
if (conf) {
if (conf->r10bio_pool)
mempool_destroy(conf->r10bio_pool);
kfree(conf->mirrors);
safe_put_page(conf->tmppage);
kfree(conf);
}
return ERR_PTR(err);
}
static int run(struct mddev *mddev)
{
struct r10conf *conf;
int i, disk_idx, chunk_size;
struct mirror_info *disk;
struct md_rdev *rdev;
sector_t size;
/*
* copy the already verified devices into our private RAID10
* bookkeeping area. [whatever we allocate in run(),
* should be freed in stop()]
*/
if (mddev->private == NULL) {
conf = setup_conf(mddev);
if (IS_ERR(conf))
return PTR_ERR(conf);
mddev->private = conf;
}
conf = mddev->private;
if (!conf)
goto out;
mddev->thread = conf->thread;
conf->thread = NULL;
chunk_size = mddev->chunk_sectors << 9;
blk_queue_io_min(mddev->queue, chunk_size);
if (conf->raid_disks % conf->near_copies)
blk_queue_io_opt(mddev->queue, chunk_size * conf->raid_disks);
else
blk_queue_io_opt(mddev->queue, chunk_size *
(conf->raid_disks / conf->near_copies));
list_for_each_entry(rdev, &mddev->disks, same_set) {
disk_idx = rdev->raid_disk;
if (disk_idx >= conf->raid_disks
|| disk_idx < 0)
continue;
disk = conf->mirrors + disk_idx;
disk->rdev = rdev;
disk_stack_limits(mddev->gendisk, rdev->bdev,
rdev->data_offset << 9);
/* as we don't honour merge_bvec_fn, we must never risk
* violating it, so limit max_segments to 1 lying
* within a single page.
*/
if (rdev->bdev->bd_disk->queue->merge_bvec_fn) {
blk_queue_max_segments(mddev->queue, 1);
blk_queue_segment_boundary(mddev->queue,
PAGE_CACHE_SIZE - 1);
}
disk->head_position = 0;
}
/* need to check that every block has at least one working mirror */
if (!enough(conf, -1)) {
printk(KERN_ERR "md/raid10:%s: not enough operational mirrors.\n",
mdname(mddev));
goto out_free_conf;
}
mddev->degraded = 0;
for (i = 0; i < conf->raid_disks; i++) {
disk = conf->mirrors + i;
if (!disk->rdev ||
!test_bit(In_sync, &disk->rdev->flags)) {
disk->head_position = 0;
mddev->degraded++;
if (disk->rdev)
conf->fullsync = 1;
}
disk->recovery_disabled = mddev->recovery_disabled - 1;
}
if (mddev->recovery_cp != MaxSector)
printk(KERN_NOTICE "md/raid10:%s: not clean"
" -- starting background reconstruction\n",
mdname(mddev));
printk(KERN_INFO
"md/raid10:%s: active with %d out of %d devices\n",
mdname(mddev), conf->raid_disks - mddev->degraded,
conf->raid_disks);
/*
* Ok, everything is just fine now
*/
mddev->dev_sectors = conf->dev_sectors;
size = raid10_size(mddev, 0, 0);
md_set_array_sectors(mddev, size);
mddev->resync_max_sectors = size;
mddev->queue->backing_dev_info.congested_fn = raid10_congested;
mddev->queue->backing_dev_info.congested_data = mddev;
/* Calculate max read-ahead size.
* We need to readahead at least twice a whole stripe....
* maybe...
*/
{
int stripe = conf->raid_disks *
((mddev->chunk_sectors << 9) / PAGE_SIZE);
stripe /= conf->near_copies;
if (mddev->queue->backing_dev_info.ra_pages < 2* stripe)
mddev->queue->backing_dev_info.ra_pages = 2* stripe;
}
if (conf->near_copies < conf->raid_disks)
blk_queue_merge_bvec(mddev->queue, raid10_mergeable_bvec);
if (md_integrity_register(mddev))
goto out_free_conf;
return 0;
out_free_conf:
md_unregister_thread(&mddev->thread);
if (conf->r10bio_pool)
mempool_destroy(conf->r10bio_pool);
safe_put_page(conf->tmppage);
kfree(conf->mirrors);
kfree(conf);
mddev->private = NULL;
out:
return -EIO;
}
static int stop(struct mddev *mddev)
{
struct r10conf *conf = mddev->private;
raise_barrier(conf, 0);
lower_barrier(conf);
md_unregister_thread(&mddev->thread);
blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
if (conf->r10bio_pool)
mempool_destroy(conf->r10bio_pool);
kfree(conf->mirrors);
kfree(conf);
mddev->private = NULL;
return 0;
}
static void raid10_quiesce(struct mddev *mddev, int state)
{
struct r10conf *conf = mddev->private;
switch(state) {
case 1:
raise_barrier(conf, 0);
break;
case 0:
lower_barrier(conf);
break;
}
}
static void *raid10_takeover_raid0(struct mddev *mddev)
{
struct md_rdev *rdev;
struct r10conf *conf;
if (mddev->degraded > 0) {
printk(KERN_ERR "md/raid10:%s: Error: degraded raid0!\n",
mdname(mddev));
return ERR_PTR(-EINVAL);
}
/* Set new parameters */
mddev->new_level = 10;
/* new layout: far_copies = 1, near_copies = 2 */
mddev->new_layout = (1<<8) + 2;
mddev->new_chunk_sectors = mddev->chunk_sectors;
mddev->delta_disks = mddev->raid_disks;
mddev->raid_disks *= 2;
/* make sure it will be not marked as dirty */
mddev->recovery_cp = MaxSector;
conf = setup_conf(mddev);
if (!IS_ERR(conf)) {
list_for_each_entry(rdev, &mddev->disks, same_set)
if (rdev->raid_disk >= 0)
rdev->new_raid_disk = rdev->raid_disk * 2;
conf->barrier = 1;
}
return conf;
}
static void *raid10_takeover(struct mddev *mddev)
{
struct r0conf *raid0_conf;
/* raid10 can take over:
* raid0 - providing it has only two drives
*/
if (mddev->level == 0) {
/* for raid0 takeover only one zone is supported */
raid0_conf = mddev->private;
if (raid0_conf->nr_strip_zones > 1) {
printk(KERN_ERR "md/raid10:%s: cannot takeover raid 0"
" with more than one zone.\n",
mdname(mddev));
return ERR_PTR(-EINVAL);
}
return raid10_takeover_raid0(mddev);
}
return ERR_PTR(-EINVAL);
}
static struct md_personality raid10_personality =
{
.name = "raid10",
.level = 10,
.owner = THIS_MODULE,
.make_request = make_request,
.run = run,
.stop = stop,
.status = status,
.error_handler = error,
.hot_add_disk = raid10_add_disk,
.hot_remove_disk= raid10_remove_disk,
.spare_active = raid10_spare_active,
.sync_request = sync_request,
.quiesce = raid10_quiesce,
.size = raid10_size,
.takeover = raid10_takeover,
};
static int __init raid_init(void)
{
return register_md_personality(&raid10_personality);
}
static void raid_exit(void)
{
unregister_md_personality(&raid10_personality);
}
module_init(raid_init);
module_exit(raid_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("RAID10 (striped mirror) personality for MD");
MODULE_ALIAS("md-personality-9"); /* RAID10 */
MODULE_ALIAS("md-raid10");
MODULE_ALIAS("md-level-10");
module_param(max_queued_requests, int, S_IRUGO|S_IWUSR);
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