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linux/drivers/md/raid5.c
NeilBrown e62e58a5ff md: use interruptible wait when duration is controlled by userspace. 
User space can set various limits on an md array so that resync waits
when it gets to a certain point, or so that I/O is blocked for a short
while.
When md is waiting against one of these limit, it should use an
interruptible wait so as not to add to the load average, and so are
not to trigger a warning if the wait goes on for too long.

Signed-off-by: NeilBrown <neilb@suse.de>
2009-07-01 13:15:35 +10:00

5418 lines
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/*
* raid5.c : Multiple Devices driver for Linux
* Copyright (C) 1996, 1997 Ingo Molnar, Miguel de Icaza, Gadi Oxman
* Copyright (C) 1999, 2000 Ingo Molnar
* Copyright (C) 2002, 2003 H. Peter Anvin
*
* RAID-4/5/6 management functions.
* Thanks to Penguin Computing for making the RAID-6 development possible
* by donating a test server!
*
* 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.
*/
/*
* BITMAP UNPLUGGING:
*
* The sequencing for updating the bitmap reliably is a little
* subtle (and I got it wrong the first time) so it deserves some
* explanation.
*
* We group bitmap updates into batches. Each batch has a number.
* We may write out several batches at once, but that isn't very important.
* conf->bm_write is the number of the last batch successfully written.
* conf->bm_flush is the number of the last batch that was closed to
* new additions.
* When we discover that we will need to write to any block in a stripe
* (in add_stripe_bio) we update the in-memory bitmap and record in sh->bm_seq
* the number of the batch it will be in. This is bm_flush+1.
* When we are ready to do a write, if that batch hasn't been written yet,
* we plug the array and queue the stripe for later.
* When an unplug happens, we increment bm_flush, thus closing the current
* batch.
* When we notice that bm_flush > bm_write, we write out all pending updates
* to the bitmap, and advance bm_write to where bm_flush was.
* This may occasionally write a bit out twice, but is sure never to
* miss any bits.
*/
#include <linux/blkdev.h>
#include <linux/kthread.h>
#include <linux/raid/pq.h>
#include <linux/async_tx.h>
#include <linux/seq_file.h>
#include "md.h"
#include "raid5.h"
#include "bitmap.h"
/*
* Stripe cache
*/
#define NR_STRIPES 256
#define STRIPE_SIZE PAGE_SIZE
#define STRIPE_SHIFT (PAGE_SHIFT - 9)
#define STRIPE_SECTORS (STRIPE_SIZE>>9)
#define IO_THRESHOLD 1
#define BYPASS_THRESHOLD 1
#define NR_HASH (PAGE_SIZE / sizeof(struct hlist_head))
#define HASH_MASK (NR_HASH - 1)
#define stripe_hash(conf, sect) (&((conf)->stripe_hashtbl[((sect) >> STRIPE_SHIFT) & HASH_MASK]))
/* bio's attached to a stripe+device for I/O are linked together in bi_sector
* order without overlap. There may be several bio's per stripe+device, and
* a bio could span several devices.
* When walking this list for a particular stripe+device, we must never proceed
* beyond a bio that extends past this device, as the next bio might no longer
* be valid.
* This macro is used to determine the 'next' bio in the list, given the sector
* of the current stripe+device
*/
#define r5_next_bio(bio, sect) ( ( (bio)->bi_sector + ((bio)->bi_size>>9) < sect + STRIPE_SECTORS) ? (bio)->bi_next : NULL)
/*
* The following can be used to debug the driver
*/
#define RAID5_PARANOIA 1
#if RAID5_PARANOIA && defined(CONFIG_SMP)
# define CHECK_DEVLOCK() assert_spin_locked(&conf->device_lock)
#else
# define CHECK_DEVLOCK()
#endif
#ifdef DEBUG
#define inline
#define __inline__
#endif
#define printk_rl(args...) ((void) (printk_ratelimit() && printk(args)))
/*
* We maintain a biased count of active stripes in the bottom 16 bits of
* bi_phys_segments, and a count of processed stripes in the upper 16 bits
*/
static inline int raid5_bi_phys_segments(struct bio *bio)
{
return bio->bi_phys_segments & 0xffff;
}
static inline int raid5_bi_hw_segments(struct bio *bio)
{
return (bio->bi_phys_segments >> 16) & 0xffff;
}
static inline int raid5_dec_bi_phys_segments(struct bio *bio)
{
--bio->bi_phys_segments;
return raid5_bi_phys_segments(bio);
}
static inline int raid5_dec_bi_hw_segments(struct bio *bio)
{
unsigned short val = raid5_bi_hw_segments(bio);
--val;
bio->bi_phys_segments = (val << 16) | raid5_bi_phys_segments(bio);
return val;
}
static inline void raid5_set_bi_hw_segments(struct bio *bio, unsigned int cnt)
{
bio->bi_phys_segments = raid5_bi_phys_segments(bio) || (cnt << 16);
}
/* Find first data disk in a raid6 stripe */
static inline int raid6_d0(struct stripe_head *sh)
{
if (sh->ddf_layout)
/* ddf always start from first device */
return 0;
/* md starts just after Q block */
if (sh->qd_idx == sh->disks - 1)
return 0;
else
return sh->qd_idx + 1;
}
static inline int raid6_next_disk(int disk, int raid_disks)
{
disk++;
return (disk < raid_disks) ? disk : 0;
}
/* When walking through the disks in a raid5, starting at raid6_d0,
* We need to map each disk to a 'slot', where the data disks are slot
* 0 .. raid_disks-3, the parity disk is raid_disks-2 and the Q disk
* is raid_disks-1. This help does that mapping.
*/
static int raid6_idx_to_slot(int idx, struct stripe_head *sh,
int *count, int syndrome_disks)
{
int slot;
if (idx == sh->pd_idx)
return syndrome_disks;
if (idx == sh->qd_idx)
return syndrome_disks + 1;
slot = (*count)++;
return slot;
}
static void return_io(struct bio *return_bi)
{
struct bio *bi = return_bi;
while (bi) {
return_bi = bi->bi_next;
bi->bi_next = NULL;
bi->bi_size = 0;
bio_endio(bi, 0);
bi = return_bi;
}
}
static void print_raid5_conf (raid5_conf_t *conf);
static int stripe_operations_active(struct stripe_head *sh)
{
return sh->check_state || sh->reconstruct_state ||
test_bit(STRIPE_BIOFILL_RUN, &sh->state) ||
test_bit(STRIPE_COMPUTE_RUN, &sh->state);
}
static void __release_stripe(raid5_conf_t *conf, struct stripe_head *sh)
{
if (atomic_dec_and_test(&sh->count)) {
BUG_ON(!list_empty(&sh->lru));
BUG_ON(atomic_read(&conf->active_stripes)==0);
if (test_bit(STRIPE_HANDLE, &sh->state)) {
if (test_bit(STRIPE_DELAYED, &sh->state)) {
list_add_tail(&sh->lru, &conf->delayed_list);
blk_plug_device(conf->mddev->queue);
} else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
sh->bm_seq - conf->seq_write > 0) {
list_add_tail(&sh->lru, &conf->bitmap_list);
blk_plug_device(conf->mddev->queue);
} else {
clear_bit(STRIPE_BIT_DELAY, &sh->state);
list_add_tail(&sh->lru, &conf->handle_list);
}
md_wakeup_thread(conf->mddev->thread);
} else {
BUG_ON(stripe_operations_active(sh));
if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
atomic_dec(&conf->preread_active_stripes);
if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD)
md_wakeup_thread(conf->mddev->thread);
}
atomic_dec(&conf->active_stripes);
if (!test_bit(STRIPE_EXPANDING, &sh->state)) {
list_add_tail(&sh->lru, &conf->inactive_list);
wake_up(&conf->wait_for_stripe);
if (conf->retry_read_aligned)
md_wakeup_thread(conf->mddev->thread);
}
}
}
}
static void release_stripe(struct stripe_head *sh)
{
raid5_conf_t *conf = sh->raid_conf;
unsigned long flags;
spin_lock_irqsave(&conf->device_lock, flags);
__release_stripe(conf, sh);
spin_unlock_irqrestore(&conf->device_lock, flags);
}
static inline void remove_hash(struct stripe_head *sh)
{
pr_debug("remove_hash(), stripe %llu\n",
(unsigned long long)sh->sector);
hlist_del_init(&sh->hash);
}
static inline void insert_hash(raid5_conf_t *conf, struct stripe_head *sh)
{
struct hlist_head *hp = stripe_hash(conf, sh->sector);
pr_debug("insert_hash(), stripe %llu\n",
(unsigned long long)sh->sector);
CHECK_DEVLOCK();
hlist_add_head(&sh->hash, hp);
}
/* find an idle stripe, make sure it is unhashed, and return it. */
static struct stripe_head *get_free_stripe(raid5_conf_t *conf)
{
struct stripe_head *sh = NULL;
struct list_head *first;
CHECK_DEVLOCK();
if (list_empty(&conf->inactive_list))
goto out;
first = conf->inactive_list.next;
sh = list_entry(first, struct stripe_head, lru);
list_del_init(first);
remove_hash(sh);
atomic_inc(&conf->active_stripes);
out:
return sh;
}
static void shrink_buffers(struct stripe_head *sh, int num)
{
struct page *p;
int i;
for (i=0; i<num ; i++) {
p = sh->dev[i].page;
if (!p)
continue;
sh->dev[i].page = NULL;
put_page(p);
}
}
static int grow_buffers(struct stripe_head *sh, int num)
{
int i;
for (i=0; i<num; i++) {
struct page *page;
if (!(page = alloc_page(GFP_KERNEL))) {
return 1;
}
sh->dev[i].page = page;
}
return 0;
}
static void raid5_build_block(struct stripe_head *sh, int i, int previous);
static void stripe_set_idx(sector_t stripe, raid5_conf_t *conf, int previous,
struct stripe_head *sh);
static void init_stripe(struct stripe_head *sh, sector_t sector, int previous)
{
raid5_conf_t *conf = sh->raid_conf;
int i;
BUG_ON(atomic_read(&sh->count) != 0);
BUG_ON(test_bit(STRIPE_HANDLE, &sh->state));
BUG_ON(stripe_operations_active(sh));
CHECK_DEVLOCK();
pr_debug("init_stripe called, stripe %llu\n",
(unsigned long long)sh->sector);
remove_hash(sh);
sh->generation = conf->generation - previous;
sh->disks = previous ? conf->previous_raid_disks : conf->raid_disks;
sh->sector = sector;
stripe_set_idx(sector, conf, previous, sh);
sh->state = 0;
for (i = sh->disks; i--; ) {
struct r5dev *dev = &sh->dev[i];
if (dev->toread || dev->read || dev->towrite || dev->written ||
test_bit(R5_LOCKED, &dev->flags)) {
printk(KERN_ERR "sector=%llx i=%d %p %p %p %p %d\n",
(unsigned long long)sh->sector, i, dev->toread,
dev->read, dev->towrite, dev->written,
test_bit(R5_LOCKED, &dev->flags));
BUG();
}
dev->flags = 0;
raid5_build_block(sh, i, previous);
}
insert_hash(conf, sh);
}
static struct stripe_head *__find_stripe(raid5_conf_t *conf, sector_t sector,
short generation)
{
struct stripe_head *sh;
struct hlist_node *hn;
CHECK_DEVLOCK();
pr_debug("__find_stripe, sector %llu\n", (unsigned long long)sector);
hlist_for_each_entry(sh, hn, stripe_hash(conf, sector), hash)
if (sh->sector == sector && sh->generation == generation)
return sh;
pr_debug("__stripe %llu not in cache\n", (unsigned long long)sector);
return NULL;
}
static void unplug_slaves(mddev_t *mddev);
static void raid5_unplug_device(struct request_queue *q);
static struct stripe_head *
get_active_stripe(raid5_conf_t *conf, sector_t sector,
int previous, int noblock, int noquiesce)
{
struct stripe_head *sh;
pr_debug("get_stripe, sector %llu\n", (unsigned long long)sector);
spin_lock_irq(&conf->device_lock);
do {
wait_event_lock_irq(conf->wait_for_stripe,
conf->quiesce == 0 || noquiesce,
conf->device_lock, /* nothing */);
sh = __find_stripe(conf, sector, conf->generation - previous);
if (!sh) {
if (!conf->inactive_blocked)
sh = get_free_stripe(conf);
if (noblock && sh == NULL)
break;
if (!sh) {
conf->inactive_blocked = 1;
wait_event_lock_irq(conf->wait_for_stripe,
!list_empty(&conf->inactive_list) &&
(atomic_read(&conf->active_stripes)
< (conf->max_nr_stripes *3/4)
|| !conf->inactive_blocked),
conf->device_lock,
raid5_unplug_device(conf->mddev->queue)
);
conf->inactive_blocked = 0;
} else
init_stripe(sh, sector, previous);
} else {
if (atomic_read(&sh->count)) {
BUG_ON(!list_empty(&sh->lru)
&& !test_bit(STRIPE_EXPANDING, &sh->state));
} else {
if (!test_bit(STRIPE_HANDLE, &sh->state))
atomic_inc(&conf->active_stripes);
if (list_empty(&sh->lru) &&
!test_bit(STRIPE_EXPANDING, &sh->state))
BUG();
list_del_init(&sh->lru);
}
}
} while (sh == NULL);
if (sh)
atomic_inc(&sh->count);
spin_unlock_irq(&conf->device_lock);
return sh;
}
static void
raid5_end_read_request(struct bio *bi, int error);
static void
raid5_end_write_request(struct bio *bi, int error);
static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
{
raid5_conf_t *conf = sh->raid_conf;
int i, disks = sh->disks;
might_sleep();
for (i = disks; i--; ) {
int rw;
struct bio *bi;
mdk_rdev_t *rdev;
if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags))
rw = WRITE;
else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
rw = READ;
else
continue;
bi = &sh->dev[i].req;
bi->bi_rw = rw;
if (rw == WRITE)
bi->bi_end_io = raid5_end_write_request;
else
bi->bi_end_io = raid5_end_read_request;
rcu_read_lock();
rdev = rcu_dereference(conf->disks[i].rdev);
if (rdev && test_bit(Faulty, &rdev->flags))
rdev = NULL;
if (rdev)
atomic_inc(&rdev->nr_pending);
rcu_read_unlock();
if (rdev) {
if (s->syncing || s->expanding || s->expanded)
md_sync_acct(rdev->bdev, STRIPE_SECTORS);
set_bit(STRIPE_IO_STARTED, &sh->state);
bi->bi_bdev = rdev->bdev;
pr_debug("%s: for %llu schedule op %ld on disc %d\n",
__func__, (unsigned long long)sh->sector,
bi->bi_rw, i);
atomic_inc(&sh->count);
bi->bi_sector = sh->sector + rdev->data_offset;
bi->bi_flags = 1 << BIO_UPTODATE;
bi->bi_vcnt = 1;
bi->bi_max_vecs = 1;
bi->bi_idx = 0;
bi->bi_io_vec = &sh->dev[i].vec;
bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
bi->bi_io_vec[0].bv_offset = 0;
bi->bi_size = STRIPE_SIZE;
bi->bi_next = NULL;
if (rw == WRITE &&
test_bit(R5_ReWrite, &sh->dev[i].flags))
atomic_add(STRIPE_SECTORS,
&rdev->corrected_errors);
generic_make_request(bi);
} else {
if (rw == WRITE)
set_bit(STRIPE_DEGRADED, &sh->state);
pr_debug("skip op %ld on disc %d for sector %llu\n",
bi->bi_rw, i, (unsigned long long)sh->sector);
clear_bit(R5_LOCKED, &sh->dev[i].flags);
set_bit(STRIPE_HANDLE, &sh->state);
}
}
}
static struct dma_async_tx_descriptor *
async_copy_data(int frombio, struct bio *bio, struct page *page,
sector_t sector, struct dma_async_tx_descriptor *tx)
{
struct bio_vec *bvl;
struct page *bio_page;
int i;
int page_offset;
if (bio->bi_sector >= sector)
page_offset = (signed)(bio->bi_sector - sector) * 512;
else
page_offset = (signed)(sector - bio->bi_sector) * -512;
bio_for_each_segment(bvl, bio, i) {
int len = bio_iovec_idx(bio, i)->bv_len;
int clen;
int b_offset = 0;
if (page_offset < 0) {
b_offset = -page_offset;
page_offset += b_offset;
len -= b_offset;
}
if (len > 0 && page_offset + len > STRIPE_SIZE)
clen = STRIPE_SIZE - page_offset;
else
clen = len;
if (clen > 0) {
b_offset += bio_iovec_idx(bio, i)->bv_offset;
bio_page = bio_iovec_idx(bio, i)->bv_page;
if (frombio)
tx = async_memcpy(page, bio_page, page_offset,
b_offset, clen,
ASYNC_TX_DEP_ACK,
tx, NULL, NULL);
else
tx = async_memcpy(bio_page, page, b_offset,
page_offset, clen,
ASYNC_TX_DEP_ACK,
tx, NULL, NULL);
}
if (clen < len) /* hit end of page */
break;
page_offset += len;
}
return tx;
}
static void ops_complete_biofill(void *stripe_head_ref)
{
struct stripe_head *sh = stripe_head_ref;
struct bio *return_bi = NULL;
raid5_conf_t *conf = sh->raid_conf;
int i;
pr_debug("%s: stripe %llu\n", __func__,
(unsigned long long)sh->sector);
/* clear completed biofills */
spin_lock_irq(&conf->device_lock);
for (i = sh->disks; i--; ) {
struct r5dev *dev = &sh->dev[i];
/* acknowledge completion of a biofill operation */
/* and check if we need to reply to a read request,
* new R5_Wantfill requests are held off until
* !STRIPE_BIOFILL_RUN
*/
if (test_and_clear_bit(R5_Wantfill, &dev->flags)) {
struct bio *rbi, *rbi2;
BUG_ON(!dev->read);
rbi = dev->read;
dev->read = NULL;
while (rbi && rbi->bi_sector <
dev->sector + STRIPE_SECTORS) {
rbi2 = r5_next_bio(rbi, dev->sector);
if (!raid5_dec_bi_phys_segments(rbi)) {
rbi->bi_next = return_bi;
return_bi = rbi;
}
rbi = rbi2;
}
}
}
spin_unlock_irq(&conf->device_lock);
clear_bit(STRIPE_BIOFILL_RUN, &sh->state);
return_io(return_bi);
set_bit(STRIPE_HANDLE, &sh->state);
release_stripe(sh);
}
static void ops_run_biofill(struct stripe_head *sh)
{
struct dma_async_tx_descriptor *tx = NULL;
raid5_conf_t *conf = sh->raid_conf;
int i;
pr_debug("%s: stripe %llu\n", __func__,
(unsigned long long)sh->sector);
for (i = sh->disks; i--; ) {
struct r5dev *dev = &sh->dev[i];
if (test_bit(R5_Wantfill, &dev->flags)) {
struct bio *rbi;
spin_lock_irq(&conf->device_lock);
dev->read = rbi = dev->toread;
dev->toread = NULL;
spin_unlock_irq(&conf->device_lock);
while (rbi && rbi->bi_sector <
dev->sector + STRIPE_SECTORS) {
tx = async_copy_data(0, rbi, dev->page,
dev->sector, tx);
rbi = r5_next_bio(rbi, dev->sector);
}
}
}
atomic_inc(&sh->count);
async_trigger_callback(ASYNC_TX_DEP_ACK | ASYNC_TX_ACK, tx,
ops_complete_biofill, sh);
}
static void ops_complete_compute5(void *stripe_head_ref)
{
struct stripe_head *sh = stripe_head_ref;
int target = sh->ops.target;
struct r5dev *tgt = &sh->dev[target];
pr_debug("%s: stripe %llu\n", __func__,
(unsigned long long)sh->sector);
set_bit(R5_UPTODATE, &tgt->flags);
BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
clear_bit(R5_Wantcompute, &tgt->flags);
clear_bit(STRIPE_COMPUTE_RUN, &sh->state);
if (sh->check_state == check_state_compute_run)
sh->check_state = check_state_compute_result;
set_bit(STRIPE_HANDLE, &sh->state);
release_stripe(sh);
}
static struct dma_async_tx_descriptor *ops_run_compute5(struct stripe_head *sh)
{
/* kernel stack size limits the total number of disks */
int disks = sh->disks;
struct page *xor_srcs[disks];
int target = sh->ops.target;
struct r5dev *tgt = &sh->dev[target];
struct page *xor_dest = tgt->page;
int count = 0;
struct dma_async_tx_descriptor *tx;
int i;
pr_debug("%s: stripe %llu block: %d\n",
__func__, (unsigned long long)sh->sector, target);
BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
for (i = disks; i--; )
if (i != target)
xor_srcs[count++] = sh->dev[i].page;
atomic_inc(&sh->count);
if (unlikely(count == 1))
tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE,
0, NULL, ops_complete_compute5, sh);
else
tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
ASYNC_TX_XOR_ZERO_DST, NULL,
ops_complete_compute5, sh);
return tx;
}
static void ops_complete_prexor(void *stripe_head_ref)
{
struct stripe_head *sh = stripe_head_ref;
pr_debug("%s: stripe %llu\n", __func__,
(unsigned long long)sh->sector);
}
static struct dma_async_tx_descriptor *
ops_run_prexor(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
{
/* kernel stack size limits the total number of disks */
int disks = sh->disks;
struct page *xor_srcs[disks];
int count = 0, pd_idx = sh->pd_idx, i;
/* existing parity data subtracted */
struct page *xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
pr_debug("%s: stripe %llu\n", __func__,
(unsigned long long)sh->sector);
for (i = disks; i--; ) {
struct r5dev *dev = &sh->dev[i];
/* Only process blocks that are known to be uptodate */
if (test_bit(R5_Wantdrain, &dev->flags))
xor_srcs[count++] = dev->page;
}
tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
ASYNC_TX_DEP_ACK | ASYNC_TX_XOR_DROP_DST, tx,
ops_complete_prexor, sh);
return tx;
}
static struct dma_async_tx_descriptor *
ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
{
int disks = sh->disks;
int i;
pr_debug("%s: stripe %llu\n", __func__,
(unsigned long long)sh->sector);
for (i = disks; i--; ) {
struct r5dev *dev = &sh->dev[i];
struct bio *chosen;
if (test_and_clear_bit(R5_Wantdrain, &dev->flags)) {
struct bio *wbi;
spin_lock(&sh->lock);
chosen = dev->towrite;
dev->towrite = NULL;
BUG_ON(dev->written);
wbi = dev->written = chosen;
spin_unlock(&sh->lock);
while (wbi && wbi->bi_sector <
dev->sector + STRIPE_SECTORS) {
tx = async_copy_data(1, wbi, dev->page,
dev->sector, tx);
wbi = r5_next_bio(wbi, dev->sector);
}
}
}
return tx;
}
static void ops_complete_postxor(void *stripe_head_ref)
{
struct stripe_head *sh = stripe_head_ref;
int disks = sh->disks, i, pd_idx = sh->pd_idx;
pr_debug("%s: stripe %llu\n", __func__,
(unsigned long long)sh->sector);
for (i = disks; i--; ) {
struct r5dev *dev = &sh->dev[i];
if (dev->written || i == pd_idx)
set_bit(R5_UPTODATE, &dev->flags);
}
if (sh->reconstruct_state == reconstruct_state_drain_run)
sh->reconstruct_state = reconstruct_state_drain_result;
else if (sh->reconstruct_state == reconstruct_state_prexor_drain_run)
sh->reconstruct_state = reconstruct_state_prexor_drain_result;
else {
BUG_ON(sh->reconstruct_state != reconstruct_state_run);
sh->reconstruct_state = reconstruct_state_result;
}
set_bit(STRIPE_HANDLE, &sh->state);
release_stripe(sh);
}
static void
ops_run_postxor(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
{
/* kernel stack size limits the total number of disks */
int disks = sh->disks;
struct page *xor_srcs[disks];
int count = 0, pd_idx = sh->pd_idx, i;
struct page *xor_dest;
int prexor = 0;
unsigned long flags;
pr_debug("%s: stripe %llu\n", __func__,
(unsigned long long)sh->sector);
/* check if prexor is active which means only process blocks
* that are part of a read-modify-write (written)
*/
if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
prexor = 1;
xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
for (i = disks; i--; ) {
struct r5dev *dev = &sh->dev[i];
if (dev->written)
xor_srcs[count++] = dev->page;
}
} else {
xor_dest = sh->dev[pd_idx].page;
for (i = disks; i--; ) {
struct r5dev *dev = &sh->dev[i];
if (i != pd_idx)
xor_srcs[count++] = dev->page;
}
}
/* 1/ if we prexor'd then the dest is reused as a source
* 2/ if we did not prexor then we are redoing the parity
* set ASYNC_TX_XOR_DROP_DST and ASYNC_TX_XOR_ZERO_DST
* for the synchronous xor case
*/
flags = ASYNC_TX_DEP_ACK | ASYNC_TX_ACK |
(prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST);
atomic_inc(&sh->count);
if (unlikely(count == 1)) {
flags &= ~(ASYNC_TX_XOR_DROP_DST | ASYNC_TX_XOR_ZERO_DST);
tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE,
flags, tx, ops_complete_postxor, sh);
} else
tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
flags, tx, ops_complete_postxor, sh);
}
static void ops_complete_check(void *stripe_head_ref)
{
struct stripe_head *sh = stripe_head_ref;
pr_debug("%s: stripe %llu\n", __func__,
(unsigned long long)sh->sector);
sh->check_state = check_state_check_result;
set_bit(STRIPE_HANDLE, &sh->state);
release_stripe(sh);
}
static void ops_run_check(struct stripe_head *sh)
{
/* kernel stack size limits the total number of disks */
int disks = sh->disks;
struct page *xor_srcs[disks];
struct dma_async_tx_descriptor *tx;
int count = 0, pd_idx = sh->pd_idx, i;
struct page *xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
pr_debug("%s: stripe %llu\n", __func__,
(unsigned long long)sh->sector);
for (i = disks; i--; ) {
struct r5dev *dev = &sh->dev[i];
if (i != pd_idx)
xor_srcs[count++] = dev->page;
}
tx = async_xor_zero_sum(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
&sh->ops.zero_sum_result, 0, NULL, NULL, NULL);
atomic_inc(&sh->count);
tx = async_trigger_callback(ASYNC_TX_DEP_ACK | ASYNC_TX_ACK, tx,
ops_complete_check, sh);
}
static void raid5_run_ops(struct stripe_head *sh, unsigned long ops_request)
{
int overlap_clear = 0, i, disks = sh->disks;
struct dma_async_tx_descriptor *tx = NULL;
if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) {
ops_run_biofill(sh);
overlap_clear++;
}
if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request)) {
tx = ops_run_compute5(sh);
/* terminate the chain if postxor is not set to be run */
if (tx && !test_bit(STRIPE_OP_POSTXOR, &ops_request))
async_tx_ack(tx);
}
if (test_bit(STRIPE_OP_PREXOR, &ops_request))
tx = ops_run_prexor(sh, tx);
if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) {
tx = ops_run_biodrain(sh, tx);
overlap_clear++;
}
if (test_bit(STRIPE_OP_POSTXOR, &ops_request))
ops_run_postxor(sh, tx);
if (test_bit(STRIPE_OP_CHECK, &ops_request))
ops_run_check(sh);
if (overlap_clear)
for (i = disks; i--; ) {
struct r5dev *dev = &sh->dev[i];
if (test_and_clear_bit(R5_Overlap, &dev->flags))
wake_up(&sh->raid_conf->wait_for_overlap);
}
}
static int grow_one_stripe(raid5_conf_t *conf)
{
struct stripe_head *sh;
sh = kmem_cache_alloc(conf->slab_cache, GFP_KERNEL);
if (!sh)
return 0;
memset(sh, 0, sizeof(*sh) + (conf->raid_disks-1)*sizeof(struct r5dev));
sh->raid_conf = conf;
spin_lock_init(&sh->lock);
if (grow_buffers(sh, conf->raid_disks)) {
shrink_buffers(sh, conf->raid_disks);
kmem_cache_free(conf->slab_cache, sh);
return 0;
}
sh->disks = conf->raid_disks;
/* we just created an active stripe so... */
atomic_set(&sh->count, 1);
atomic_inc(&conf->active_stripes);
INIT_LIST_HEAD(&sh->lru);
release_stripe(sh);
return 1;
}
static int grow_stripes(raid5_conf_t *conf, int num)
{
struct kmem_cache *sc;
int devs = conf->raid_disks;
sprintf(conf->cache_name[0],
"raid%d-%s", conf->level, mdname(conf->mddev));
sprintf(conf->cache_name[1],
"raid%d-%s-alt", conf->level, mdname(conf->mddev));
conf->active_name = 0;
sc = kmem_cache_create(conf->cache_name[conf->active_name],
sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev),
0, 0, NULL);
if (!sc)
return 1;
conf->slab_cache = sc;
conf->pool_size = devs;
while (num--)
if (!grow_one_stripe(conf))
return 1;
return 0;
}
static int resize_stripes(raid5_conf_t *conf, int newsize)
{
/* Make all the stripes able to hold 'newsize' devices.
* New slots in each stripe get 'page' set to a new page.
*
* This happens in stages:
* 1/ create a new kmem_cache and allocate the required number of
* stripe_heads.
* 2/ gather all the old stripe_heads and tranfer the pages across
* to the new stripe_heads. This will have the side effect of
* freezing the array as once all stripe_heads have been collected,
* no IO will be possible. Old stripe heads are freed once their
* pages have been transferred over, and the old kmem_cache is
* freed when all stripes are done.
* 3/ reallocate conf->disks to be suitable bigger. If this fails,
* we simple return a failre status - no need to clean anything up.
* 4/ allocate new pages for the new slots in the new stripe_heads.
* If this fails, we don't bother trying the shrink the
* stripe_heads down again, we just leave them as they are.
* As each stripe_head is processed the new one is released into
* active service.
*
* Once step2 is started, we cannot afford to wait for a write,
* so we use GFP_NOIO allocations.
*/
struct stripe_head *osh, *nsh;
LIST_HEAD(newstripes);
struct disk_info *ndisks;
int err;
struct kmem_cache *sc;
int i;
if (newsize <= conf->pool_size)
return 0; /* never bother to shrink */
err = md_allow_write(conf->mddev);
if (err)
return err;
/* Step 1 */
sc = kmem_cache_create(conf->cache_name[1-conf->active_name],
sizeof(struct stripe_head)+(newsize-1)*sizeof(struct r5dev),
0, 0, NULL);
if (!sc)
return -ENOMEM;
for (i = conf->max_nr_stripes; i; i--) {
nsh = kmem_cache_alloc(sc, GFP_KERNEL);
if (!nsh)
break;
memset(nsh, 0, sizeof(*nsh) + (newsize-1)*sizeof(struct r5dev));
nsh->raid_conf = conf;
spin_lock_init(&nsh->lock);
list_add(&nsh->lru, &newstripes);
}
if (i) {
/* didn't get enough, give up */
while (!list_empty(&newstripes)) {
nsh = list_entry(newstripes.next, struct stripe_head, lru);
list_del(&nsh->lru);
kmem_cache_free(sc, nsh);
}
kmem_cache_destroy(sc);
return -ENOMEM;
}
/* Step 2 - Must use GFP_NOIO now.
* OK, we have enough stripes, start collecting inactive
* stripes and copying them over
*/
list_for_each_entry(nsh, &newstripes, lru) {
spin_lock_irq(&conf->device_lock);
wait_event_lock_irq(conf->wait_for_stripe,
!list_empty(&conf->inactive_list),
conf->device_lock,
unplug_slaves(conf->mddev)
);
osh = get_free_stripe(conf);
spin_unlock_irq(&conf->device_lock);
atomic_set(&nsh->count, 1);
for(i=0; i<conf->pool_size; i++)
nsh->dev[i].page = osh->dev[i].page;
for( ; i<newsize; i++)
nsh->dev[i].page = NULL;
kmem_cache_free(conf->slab_cache, osh);
}
kmem_cache_destroy(conf->slab_cache);
/* Step 3.
* At this point, we are holding all the stripes so the array
* is completely stalled, so now is a good time to resize
* conf->disks.
*/
ndisks = kzalloc(newsize * sizeof(struct disk_info), GFP_NOIO);
if (ndisks) {
for (i=0; i<conf->raid_disks; i++)
ndisks[i] = conf->disks[i];
kfree(conf->disks);
conf->disks = ndisks;
} else
err = -ENOMEM;
/* Step 4, return new stripes to service */
while(!list_empty(&newstripes)) {
nsh = list_entry(newstripes.next, struct stripe_head, lru);
list_del_init(&nsh->lru);
for (i=conf->raid_disks; i < newsize; i++)
if (nsh->dev[i].page == NULL) {
struct page *p = alloc_page(GFP_NOIO);
nsh->dev[i].page = p;
if (!p)
err = -ENOMEM;
}
release_stripe(nsh);
}
/* critical section pass, GFP_NOIO no longer needed */
conf->slab_cache = sc;
conf->active_name = 1-conf->active_name;
conf->pool_size = newsize;
return err;
}
static int drop_one_stripe(raid5_conf_t *conf)
{
struct stripe_head *sh;
spin_lock_irq(&conf->device_lock);
sh = get_free_stripe(conf);
spin_unlock_irq(&conf->device_lock);
if (!sh)
return 0;
BUG_ON(atomic_read(&sh->count));
shrink_buffers(sh, conf->pool_size);
kmem_cache_free(conf->slab_cache, sh);
atomic_dec(&conf->active_stripes);
return 1;
}
static void shrink_stripes(raid5_conf_t *conf)
{
while (drop_one_stripe(conf))
;
if (conf->slab_cache)
kmem_cache_destroy(conf->slab_cache);
conf->slab_cache = NULL;
}
static void raid5_end_read_request(struct bio * bi, int error)
{
struct stripe_head *sh = bi->bi_private;
raid5_conf_t *conf = sh->raid_conf;
int disks = sh->disks, i;
int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
char b[BDEVNAME_SIZE];
mdk_rdev_t *rdev;
for (i=0 ; i<disks; i++)
if (bi == &sh->dev[i].req)
break;
pr_debug("end_read_request %llu/%d, count: %d, uptodate %d.\n",
(unsigned long long)sh->sector, i, atomic_read(&sh->count),
uptodate);
if (i == disks) {
BUG();
return;
}
if (uptodate) {
set_bit(R5_UPTODATE, &sh->dev[i].flags);
if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
rdev = conf->disks[i].rdev;
printk_rl(KERN_INFO "raid5:%s: read error corrected"
" (%lu sectors at %llu on %s)\n",
mdname(conf->mddev), STRIPE_SECTORS,
(unsigned long long)(sh->sector
+ rdev->data_offset),
bdevname(rdev->bdev, b));
clear_bit(R5_ReadError, &sh->dev[i].flags);
clear_bit(R5_ReWrite, &sh->dev[i].flags);
}
if (atomic_read(&conf->disks[i].rdev->read_errors))
atomic_set(&conf->disks[i].rdev->read_errors, 0);
} else {
const char *bdn = bdevname(conf->disks[i].rdev->bdev, b);
int retry = 0;
rdev = conf->disks[i].rdev;
clear_bit(R5_UPTODATE, &sh->dev[i].flags);
atomic_inc(&rdev->read_errors);
if (conf->mddev->degraded)
printk_rl(KERN_WARNING
"raid5:%s: read error not correctable "
"(sector %llu on %s).\n",
mdname(conf->mddev),
(unsigned long long)(sh->sector
+ rdev->data_offset),
bdn);
else if (test_bit(R5_ReWrite, &sh->dev[i].flags))
/* Oh, no!!! */
printk_rl(KERN_WARNING
"raid5:%s: read error NOT corrected!! "
"(sector %llu on %s).\n",
mdname(conf->mddev),
(unsigned long long)(sh->sector
+ rdev->data_offset),
bdn);
else if (atomic_read(&rdev->read_errors)
> conf->max_nr_stripes)
printk(KERN_WARNING
"raid5:%s: Too many read errors, failing device %s.\n",
mdname(conf->mddev), bdn);
else
retry = 1;
if (retry)
set_bit(R5_ReadError, &sh->dev[i].flags);
else {
clear_bit(R5_ReadError, &sh->dev[i].flags);
clear_bit(R5_ReWrite, &sh->dev[i].flags);
md_error(conf->mddev, rdev);
}
}
rdev_dec_pending(conf->disks[i].rdev, conf->mddev);
clear_bit(R5_LOCKED, &sh->dev[i].flags);
set_bit(STRIPE_HANDLE, &sh->state);
release_stripe(sh);
}
static void raid5_end_write_request(struct bio *bi, int error)
{
struct stripe_head *sh = bi->bi_private;
raid5_conf_t *conf = sh->raid_conf;
int disks = sh->disks, i;
int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
for (i=0 ; i<disks; i++)
if (bi == &sh->dev[i].req)
break;
pr_debug("end_write_request %llu/%d, count %d, uptodate: %d.\n",
(unsigned long long)sh->sector, i, atomic_read(&sh->count),
uptodate);
if (i == disks) {
BUG();
return;
}
if (!uptodate)
md_error(conf->mddev, conf->disks[i].rdev);
rdev_dec_pending(conf->disks[i].rdev, conf->mddev);
clear_bit(R5_LOCKED, &sh->dev[i].flags);
set_bit(STRIPE_HANDLE, &sh->state);
release_stripe(sh);
}
static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous);
static void raid5_build_block(struct stripe_head *sh, int i, int previous)
{
struct r5dev *dev = &sh->dev[i];
bio_init(&dev->req);
dev->req.bi_io_vec = &dev->vec;
dev->req.bi_vcnt++;
dev->req.bi_max_vecs++;
dev->vec.bv_page = dev->page;
dev->vec.bv_len = STRIPE_SIZE;
dev->vec.bv_offset = 0;
dev->req.bi_sector = sh->sector;
dev->req.bi_private = sh;
dev->flags = 0;
dev->sector = compute_blocknr(sh, i, previous);
}
static void error(mddev_t *mddev, mdk_rdev_t *rdev)
{
char b[BDEVNAME_SIZE];
raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
pr_debug("raid5: error called\n");
if (!test_bit(Faulty, &rdev->flags)) {
set_bit(MD_CHANGE_DEVS, &mddev->flags);
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 was running, make sure it aborts.
*/
set_bit(MD_RECOVERY_INTR, &mddev->recovery);
}
set_bit(Faulty, &rdev->flags);
printk(KERN_ALERT
"raid5: Disk failure on %s, disabling device.\n"
"raid5: Operation continuing on %d devices.\n",
bdevname(rdev->bdev,b), conf->raid_disks - mddev->degraded);
}
}
/*
* Input: a 'big' sector number,
* Output: index of the data and parity disk, and the sector # in them.
*/
static sector_t raid5_compute_sector(raid5_conf_t *conf, sector_t r_sector,
int previous, int *dd_idx,
struct stripe_head *sh)
{
long stripe;
unsigned long chunk_number;
unsigned int chunk_offset;
int pd_idx, qd_idx;
int ddf_layout = 0;
sector_t new_sector;
int algorithm = previous ? conf->prev_algo
: conf->algorithm;
int sectors_per_chunk = previous ? conf->prev_chunk_sectors
: conf->chunk_sectors;
int raid_disks = previous ? conf->previous_raid_disks
: conf->raid_disks;
int data_disks = raid_disks - conf->max_degraded;
/* First compute the information on this sector */
/*
* Compute the chunk number and the sector offset inside the chunk
*/
chunk_offset = sector_div(r_sector, sectors_per_chunk);
chunk_number = r_sector;
BUG_ON(r_sector != chunk_number);
/*
* Compute the stripe number
*/
stripe = chunk_number / data_disks;
/*
* Compute the data disk and parity disk indexes inside the stripe
*/
*dd_idx = chunk_number % data_disks;
/*
* Select the parity disk based on the user selected algorithm.
*/
pd_idx = qd_idx = ~0;
switch(conf->level) {
case 4:
pd_idx = data_disks;
break;
case 5:
switch (algorithm) {
case ALGORITHM_LEFT_ASYMMETRIC:
pd_idx = data_disks - stripe % raid_disks;
if (*dd_idx >= pd_idx)
(*dd_idx)++;
break;
case ALGORITHM_RIGHT_ASYMMETRIC:
pd_idx = stripe % raid_disks;
if (*dd_idx >= pd_idx)
(*dd_idx)++;
break;
case ALGORITHM_LEFT_SYMMETRIC:
pd_idx = data_disks - stripe % raid_disks;
*dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
break;
case ALGORITHM_RIGHT_SYMMETRIC:
pd_idx = stripe % raid_disks;
*dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
break;
case ALGORITHM_PARITY_0:
pd_idx = 0;
(*dd_idx)++;
break;
case ALGORITHM_PARITY_N:
pd_idx = data_disks;
break;
default:
printk(KERN_ERR "raid5: unsupported algorithm %d\n",
algorithm);
BUG();
}
break;
case 6:
switch (algorithm) {
case ALGORITHM_LEFT_ASYMMETRIC:
pd_idx = raid_disks - 1 - (stripe % raid_disks);
qd_idx = pd_idx + 1;
if (pd_idx == raid_disks-1) {
(*dd_idx)++; /* Q D D D P */
qd_idx = 0;
} else if (*dd_idx >= pd_idx)
(*dd_idx) += 2; /* D D P Q D */
break;
case ALGORITHM_RIGHT_ASYMMETRIC:
pd_idx = stripe % raid_disks;
qd_idx = pd_idx + 1;
if (pd_idx == raid_disks-1) {
(*dd_idx)++; /* Q D D D P */
qd_idx = 0;
} else if (*dd_idx >= pd_idx)
(*dd_idx) += 2; /* D D P Q D */
break;
case ALGORITHM_LEFT_SYMMETRIC:
pd_idx = raid_disks - 1 - (stripe % raid_disks);
qd_idx = (pd_idx + 1) % raid_disks;
*dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
break;
case ALGORITHM_RIGHT_SYMMETRIC:
pd_idx = stripe % raid_disks;
qd_idx = (pd_idx + 1) % raid_disks;
*dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
break;
case ALGORITHM_PARITY_0:
pd_idx = 0;
qd_idx = 1;
(*dd_idx) += 2;
break;
case ALGORITHM_PARITY_N:
pd_idx = data_disks;
qd_idx = data_disks + 1;
break;
case ALGORITHM_ROTATING_ZERO_RESTART:
/* Exactly the same as RIGHT_ASYMMETRIC, but or
* of blocks for computing Q is different.
*/
pd_idx = stripe % raid_disks;
qd_idx = pd_idx + 1;
if (pd_idx == raid_disks-1) {
(*dd_idx)++; /* Q D D D P */
qd_idx = 0;
} else if (*dd_idx >= pd_idx)
(*dd_idx) += 2; /* D D P Q D */
ddf_layout = 1;
break;
case ALGORITHM_ROTATING_N_RESTART:
/* Same a left_asymmetric, by first stripe is
* D D D P Q rather than
* Q D D D P
*/
pd_idx = raid_disks - 1 - ((stripe + 1) % raid_disks);
qd_idx = pd_idx + 1;
if (pd_idx == raid_disks-1) {
(*dd_idx)++; /* Q D D D P */
qd_idx = 0;
} else if (*dd_idx >= pd_idx)
(*dd_idx) += 2; /* D D P Q D */
ddf_layout = 1;
break;
case ALGORITHM_ROTATING_N_CONTINUE:
/* Same as left_symmetric but Q is before P */
pd_idx = raid_disks - 1 - (stripe % raid_disks);
qd_idx = (pd_idx + raid_disks - 1) % raid_disks;
*dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
ddf_layout = 1;
break;
case ALGORITHM_LEFT_ASYMMETRIC_6:
/* RAID5 left_asymmetric, with Q on last device */
pd_idx = data_disks - stripe % (raid_disks-1);
if (*dd_idx >= pd_idx)
(*dd_idx)++;
qd_idx = raid_disks - 1;
break;
case ALGORITHM_RIGHT_ASYMMETRIC_6:
pd_idx = stripe % (raid_disks-1);
if (*dd_idx >= pd_idx)
(*dd_idx)++;
qd_idx = raid_disks - 1;
break;
case ALGORITHM_LEFT_SYMMETRIC_6:
pd_idx = data_disks - stripe % (raid_disks-1);
*dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
qd_idx = raid_disks - 1;
break;
case ALGORITHM_RIGHT_SYMMETRIC_6:
pd_idx = stripe % (raid_disks-1);
*dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
qd_idx = raid_disks - 1;
break;
case ALGORITHM_PARITY_0_6:
pd_idx = 0;
(*dd_idx)++;
qd_idx = raid_disks - 1;
break;
default:
printk(KERN_CRIT "raid6: unsupported algorithm %d\n",
algorithm);
BUG();
}
break;
}
if (sh) {
sh->pd_idx = pd_idx;
sh->qd_idx = qd_idx;
sh->ddf_layout = ddf_layout;
}
/*
* Finally, compute the new sector number
*/
new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset;
return new_sector;
}
static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous)
{
raid5_conf_t *conf = sh->raid_conf;
int raid_disks = sh->disks;
int data_disks = raid_disks - conf->max_degraded;
sector_t new_sector = sh->sector, check;
int sectors_per_chunk = previous ? conf->prev_chunk_sectors
: conf->chunk_sectors;
int algorithm = previous ? conf->prev_algo
: conf->algorithm;
sector_t stripe;
int chunk_offset;
int chunk_number, dummy1, dd_idx = i;
sector_t r_sector;
struct stripe_head sh2;
chunk_offset = sector_div(new_sector, sectors_per_chunk);
stripe = new_sector;
BUG_ON(new_sector != stripe);
if (i == sh->pd_idx)
return 0;
switch(conf->level) {
case 4: break;
case 5:
switch (algorithm) {
case ALGORITHM_LEFT_ASYMMETRIC:
case ALGORITHM_RIGHT_ASYMMETRIC:
if (i > sh->pd_idx)
i--;
break;
case ALGORITHM_LEFT_SYMMETRIC:
case ALGORITHM_RIGHT_SYMMETRIC:
if (i < sh->pd_idx)
i += raid_disks;
i -= (sh->pd_idx + 1);
break;
case ALGORITHM_PARITY_0:
i -= 1;
break;
case ALGORITHM_PARITY_N:
break;
default:
printk(KERN_ERR "raid5: unsupported algorithm %d\n",
algorithm);
BUG();
}
break;
case 6:
if (i == sh->qd_idx)
return 0; /* It is the Q disk */
switch (algorithm) {
case ALGORITHM_LEFT_ASYMMETRIC:
case ALGORITHM_RIGHT_ASYMMETRIC:
case ALGORITHM_ROTATING_ZERO_RESTART:
case ALGORITHM_ROTATING_N_RESTART:
if (sh->pd_idx == raid_disks-1)
i--; /* Q D D D P */
else if (i > sh->pd_idx)
i -= 2; /* D D P Q D */
break;
case ALGORITHM_LEFT_SYMMETRIC:
case ALGORITHM_RIGHT_SYMMETRIC:
if (sh->pd_idx == raid_disks-1)
i--; /* Q D D D P */
else {
/* D D P Q D */
if (i < sh->pd_idx)
i += raid_disks;
i -= (sh->pd_idx + 2);
}
break;
case ALGORITHM_PARITY_0:
i -= 2;
break;
case ALGORITHM_PARITY_N:
break;
case ALGORITHM_ROTATING_N_CONTINUE:
if (sh->pd_idx == 0)
i--; /* P D D D Q */
else if (i > sh->pd_idx)
i -= 2; /* D D Q P D */
break;
case ALGORITHM_LEFT_ASYMMETRIC_6:
case ALGORITHM_RIGHT_ASYMMETRIC_6:
if (i > sh->pd_idx)
i--;
break;
case ALGORITHM_LEFT_SYMMETRIC_6:
case ALGORITHM_RIGHT_SYMMETRIC_6:
if (i < sh->pd_idx)
i += data_disks + 1;
i -= (sh->pd_idx + 1);
break;
case ALGORITHM_PARITY_0_6:
i -= 1;
break;
default:
printk(KERN_CRIT "raid6: unsupported algorithm %d\n",
algorithm);
BUG();
}
break;
}
chunk_number = stripe * data_disks + i;
r_sector = (sector_t)chunk_number * sectors_per_chunk + chunk_offset;
check = raid5_compute_sector(conf, r_sector,
previous, &dummy1, &sh2);
if (check != sh->sector || dummy1 != dd_idx || sh2.pd_idx != sh->pd_idx
|| sh2.qd_idx != sh->qd_idx) {
printk(KERN_ERR "compute_blocknr: map not correct\n");
return 0;
}
return r_sector;
}
/*
* Copy data between a page in the stripe cache, and one or more bion
* The page could align with the middle of the bio, or there could be
* several bion, each with several bio_vecs, which cover part of the page
* Multiple bion are linked together on bi_next. There may be extras
* at the end of this list. We ignore them.
*/
static void copy_data(int frombio, struct bio *bio,
struct page *page,
sector_t sector)
{
char *pa = page_address(page);
struct bio_vec *bvl;
int i;
int page_offset;
if (bio->bi_sector >= sector)
page_offset = (signed)(bio->bi_sector - sector) * 512;
else
page_offset = (signed)(sector - bio->bi_sector) * -512;
bio_for_each_segment(bvl, bio, i) {
int len = bio_iovec_idx(bio,i)->bv_len;
int clen;
int b_offset = 0;
if (page_offset < 0) {
b_offset = -page_offset;
page_offset += b_offset;
len -= b_offset;
}
if (len > 0 && page_offset + len > STRIPE_SIZE)
clen = STRIPE_SIZE - page_offset;
else clen = len;
if (clen > 0) {
char *ba = __bio_kmap_atomic(bio, i, KM_USER0);
if (frombio)
memcpy(pa+page_offset, ba+b_offset, clen);
else
memcpy(ba+b_offset, pa+page_offset, clen);
__bio_kunmap_atomic(ba, KM_USER0);
}
if (clen < len) /* hit end of page */
break;
page_offset += len;
}
}
#define check_xor() do { \
if (count == MAX_XOR_BLOCKS) { \
xor_blocks(count, STRIPE_SIZE, dest, ptr);\
count = 0; \
} \
} while(0)
static void compute_parity6(struct stripe_head *sh, int method)
{
raid5_conf_t *conf = sh->raid_conf;
int i, pd_idx, qd_idx, d0_idx, disks = sh->disks, count;
int syndrome_disks = sh->ddf_layout ? disks : (disks - 2);
struct bio *chosen;
/**** FIX THIS: This could be very bad if disks is close to 256 ****/
void *ptrs[syndrome_disks+2];
pd_idx = sh->pd_idx;
qd_idx = sh->qd_idx;
d0_idx = raid6_d0(sh);
pr_debug("compute_parity, stripe %llu, method %d\n",
(unsigned long long)sh->sector, method);
switch(method) {
case READ_MODIFY_WRITE:
BUG(); /* READ_MODIFY_WRITE N/A for RAID-6 */
case RECONSTRUCT_WRITE:
for (i= disks; i-- ;)
if ( i != pd_idx && i != qd_idx && sh->dev[i].towrite ) {
chosen = sh->dev[i].towrite;
sh->dev[i].towrite = NULL;
if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
wake_up(&conf->wait_for_overlap);
BUG_ON(sh->dev[i].written);
sh->dev[i].written = chosen;
}
break;
case CHECK_PARITY:
BUG(); /* Not implemented yet */
}
for (i = disks; i--;)
if (sh->dev[i].written) {
sector_t sector = sh->dev[i].sector;
struct bio *wbi = sh->dev[i].written;
while (wbi && wbi->bi_sector < sector + STRIPE_SECTORS) {
copy_data(1, wbi, sh->dev[i].page, sector);
wbi = r5_next_bio(wbi, sector);
}
set_bit(R5_LOCKED, &sh->dev[i].flags);
set_bit(R5_UPTODATE, &sh->dev[i].flags);
}
/* Note that unlike RAID-5, the ordering of the disks matters greatly.*/
for (i = 0; i < disks; i++)
ptrs[i] = (void *)raid6_empty_zero_page;
count = 0;
i = d0_idx;
do {
int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
ptrs[slot] = page_address(sh->dev[i].page);
if (slot < syndrome_disks &&
!test_bit(R5_UPTODATE, &sh->dev[i].flags)) {
printk(KERN_ERR "block %d/%d not uptodate "
"on parity calc\n", i, count);
BUG();
}
i = raid6_next_disk(i, disks);
} while (i != d0_idx);
BUG_ON(count != syndrome_disks);
raid6_call.gen_syndrome(syndrome_disks+2, STRIPE_SIZE, ptrs);
switch(method) {
case RECONSTRUCT_WRITE:
set_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
set_bit(R5_UPTODATE, &sh->dev[qd_idx].flags);
set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
set_bit(R5_LOCKED, &sh->dev[qd_idx].flags);
break;
case UPDATE_PARITY:
set_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
set_bit(R5_UPTODATE, &sh->dev[qd_idx].flags);
break;
}
}
/* Compute one missing block */
static void compute_block_1(struct stripe_head *sh, int dd_idx, int nozero)
{
int i, count, disks = sh->disks;
void *ptr[MAX_XOR_BLOCKS], *dest, *p;
int qd_idx = sh->qd_idx;
pr_debug("compute_block_1, stripe %llu, idx %d\n",
(unsigned long long)sh->sector, dd_idx);
if ( dd_idx == qd_idx ) {
/* We're actually computing the Q drive */
compute_parity6(sh, UPDATE_PARITY);
} else {
dest = page_address(sh->dev[dd_idx].page);
if (!nozero) memset(dest, 0, STRIPE_SIZE);
count = 0;
for (i = disks ; i--; ) {
if (i == dd_idx || i == qd_idx)
continue;
p = page_address(sh->dev[i].page);
if (test_bit(R5_UPTODATE, &sh->dev[i].flags))
ptr[count++] = p;
else
printk("compute_block() %d, stripe %llu, %d"
" not present\n", dd_idx,
(unsigned long long)sh->sector, i);
check_xor();
}
if (count)
xor_blocks(count, STRIPE_SIZE, dest, ptr);
if (!nozero) set_bit(R5_UPTODATE, &sh->dev[dd_idx].flags);
else clear_bit(R5_UPTODATE, &sh->dev[dd_idx].flags);
}
}
/* Compute two missing blocks */
static void compute_block_2(struct stripe_head *sh, int dd_idx1, int dd_idx2)
{
int i, count, disks = sh->disks;
int syndrome_disks = sh->ddf_layout ? disks : disks-2;
int d0_idx = raid6_d0(sh);
int faila = -1, failb = -1;
/**** FIX THIS: This could be very bad if disks is close to 256 ****/
void *ptrs[syndrome_disks+2];
for (i = 0; i < disks ; i++)
ptrs[i] = (void *)raid6_empty_zero_page;
count = 0;
i = d0_idx;
do {
int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
ptrs[slot] = page_address(sh->dev[i].page);
if (i == dd_idx1)
faila = slot;
if (i == dd_idx2)
failb = slot;
i = raid6_next_disk(i, disks);
} while (i != d0_idx);
BUG_ON(count != syndrome_disks);
BUG_ON(faila == failb);
if ( failb < faila ) { int tmp = faila; faila = failb; failb = tmp; }
pr_debug("compute_block_2, stripe %llu, idx %d,%d (%d,%d)\n",
(unsigned long long)sh->sector, dd_idx1, dd_idx2,
faila, failb);
if (failb == syndrome_disks+1) {
/* Q disk is one of the missing disks */
if (faila == syndrome_disks) {
/* Missing P+Q, just recompute */
compute_parity6(sh, UPDATE_PARITY);
return;
} else {
/* We're missing D+Q; recompute D from P */
compute_block_1(sh, ((dd_idx1 == sh->qd_idx) ?
dd_idx2 : dd_idx1),
0);
compute_parity6(sh, UPDATE_PARITY); /* Is this necessary? */
return;
}
}
/* We're missing D+P or D+D; */
if (failb == syndrome_disks) {
/* We're missing D+P. */
raid6_datap_recov(syndrome_disks+2, STRIPE_SIZE, faila, ptrs);
} else {
/* We're missing D+D. */
raid6_2data_recov(syndrome_disks+2, STRIPE_SIZE, faila, failb,
ptrs);
}
/* Both the above update both missing blocks */
set_bit(R5_UPTODATE, &sh->dev[dd_idx1].flags);
set_bit(R5_UPTODATE, &sh->dev[dd_idx2].flags);
}
static void
schedule_reconstruction5(struct stripe_head *sh, struct stripe_head_state *s,
int rcw, int expand)
{
int i, pd_idx = sh->pd_idx, disks = sh->disks;
if (rcw) {
/* if we are not expanding this is a proper write request, and
* there will be bios with new data to be drained into the
* stripe cache
*/
if (!expand) {
sh->reconstruct_state = reconstruct_state_drain_run;
set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
} else
sh->reconstruct_state = reconstruct_state_run;
set_bit(STRIPE_OP_POSTXOR, &s->ops_request);
for (i = disks; i--; ) {
struct r5dev *dev = &sh->dev[i];
if (dev->towrite) {
set_bit(R5_LOCKED, &dev->flags);
set_bit(R5_Wantdrain, &dev->flags);
if (!expand)
clear_bit(R5_UPTODATE, &dev->flags);
s->locked++;
}
}
if (s->locked + 1 == disks)
if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state))
atomic_inc(&sh->raid_conf->pending_full_writes);
} else {
BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) ||
test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags)));
sh->reconstruct_state = reconstruct_state_prexor_drain_run;
set_bit(STRIPE_OP_PREXOR, &s->ops_request);
set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
set_bit(STRIPE_OP_POSTXOR, &s->ops_request);
for (i = disks; i--; ) {
struct r5dev *dev = &sh->dev[i];
if (i == pd_idx)
continue;
if (dev->towrite &&
(test_bit(R5_UPTODATE, &dev->flags) ||
test_bit(R5_Wantcompute, &dev->flags))) {
set_bit(R5_Wantdrain, &dev->flags);
set_bit(R5_LOCKED, &dev->flags);
clear_bit(R5_UPTODATE, &dev->flags);
s->locked++;
}
}
}
/* keep the parity disk locked while asynchronous operations
* are in flight
*/
set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
s->locked++;
pr_debug("%s: stripe %llu locked: %d ops_request: %lx\n",
__func__, (unsigned long long)sh->sector,
s->locked, s->ops_request);
}
/*
* Each stripe/dev can have one or more bion attached.
* toread/towrite point to the first in a chain.
* The bi_next chain must be in order.
*/
static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, int forwrite)
{
struct bio **bip;
raid5_conf_t *conf = sh->raid_conf;
int firstwrite=0;
pr_debug("adding bh b#%llu to stripe s#%llu\n",
(unsigned long long)bi->bi_sector,
(unsigned long long)sh->sector);
spin_lock(&sh->lock);
spin_lock_irq(&conf->device_lock);
if (forwrite) {
bip = &sh->dev[dd_idx].towrite;
if (*bip == NULL && sh->dev[dd_idx].written == NULL)
firstwrite = 1;
} else
bip = &sh->dev[dd_idx].toread;
while (*bip && (*bip)->bi_sector < bi->bi_sector) {
if ((*bip)->bi_sector + ((*bip)->bi_size >> 9) > bi->bi_sector)
goto overlap;
bip = & (*bip)->bi_next;
}
if (*bip && (*bip)->bi_sector < bi->bi_sector + ((bi->bi_size)>>9))
goto overlap;
BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next);
if (*bip)
bi->bi_next = *bip;
*bip = bi;
bi->bi_phys_segments++;
spin_unlock_irq(&conf->device_lock);
spin_unlock(&sh->lock);
pr_debug("added bi b#%llu to stripe s#%llu, disk %d.\n",
(unsigned long long)bi->bi_sector,
(unsigned long long)sh->sector, dd_idx);
if (conf->mddev->bitmap && firstwrite) {
bitmap_startwrite(conf->mddev->bitmap, sh->sector,
STRIPE_SECTORS, 0);
sh->bm_seq = conf->seq_flush+1;
set_bit(STRIPE_BIT_DELAY, &sh->state);
}
if (forwrite) {
/* check if page is covered */
sector_t sector = sh->dev[dd_idx].sector;
for (bi=sh->dev[dd_idx].towrite;
sector < sh->dev[dd_idx].sector + STRIPE_SECTORS &&
bi && bi->bi_sector <= sector;
bi = r5_next_bio(bi, sh->dev[dd_idx].sector)) {
if (bi->bi_sector + (bi->bi_size>>9) >= sector)
sector = bi->bi_sector + (bi->bi_size>>9);
}
if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS)
set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags);
}
return 1;
overlap:
set_bit(R5_Overlap, &sh->dev[dd_idx].flags);
spin_unlock_irq(&conf->device_lock);
spin_unlock(&sh->lock);
return 0;
}
static void end_reshape(raid5_conf_t *conf);
static int page_is_zero(struct page *p)
{
char *a = page_address(p);
return ((*(u32*)a) == 0 &&
memcmp(a, a+4, STRIPE_SIZE-4)==0);
}
static void stripe_set_idx(sector_t stripe, raid5_conf_t *conf, int previous,
struct stripe_head *sh)
{
int sectors_per_chunk =
previous ? conf->prev_chunk_sectors : conf->chunk_sectors;
int dd_idx;
int chunk_offset = sector_div(stripe, sectors_per_chunk);
int disks = previous ? conf->previous_raid_disks : conf->raid_disks;
raid5_compute_sector(conf,
stripe * (disks - conf->max_degraded)
*sectors_per_chunk + chunk_offset,
previous,
&dd_idx, sh);
}
static void
handle_failed_stripe(raid5_conf_t *conf, struct stripe_head *sh,
struct stripe_head_state *s, int disks,
struct bio **return_bi)
{
int i;
for (i = disks; i--; ) {
struct bio *bi;
int bitmap_end = 0;
if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
mdk_rdev_t *rdev;
rcu_read_lock();
rdev = rcu_dereference(conf->disks[i].rdev);
if (rdev && test_bit(In_sync, &rdev->flags))
/* multiple read failures in one stripe */
md_error(conf->mddev, rdev);
rcu_read_unlock();
}
spin_lock_irq(&conf->device_lock);
/* fail all writes first */
bi = sh->dev[i].towrite;
sh->dev[i].towrite = NULL;
if (bi) {
s->to_write--;
bitmap_end = 1;
}
if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
wake_up(&conf->wait_for_overlap);
while (bi && bi->bi_sector <
sh->dev[i].sector + STRIPE_SECTORS) {
struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector);
clear_bit(BIO_UPTODATE, &bi->bi_flags);
if (!raid5_dec_bi_phys_segments(bi)) {
md_write_end(conf->mddev);
bi->bi_next = *return_bi;
*return_bi = bi;
}
bi = nextbi;
}
/* and fail all 'written' */
bi = sh->dev[i].written;
sh->dev[i].written = NULL;
if (bi) bitmap_end = 1;
while (bi && bi->bi_sector <
sh->dev[i].sector + STRIPE_SECTORS) {
struct bio *bi2 = r5_next_bio(bi, sh->dev[i].sector);
clear_bit(BIO_UPTODATE, &bi->bi_flags);
if (!raid5_dec_bi_phys_segments(bi)) {
md_write_end(conf->mddev);
bi->bi_next = *return_bi;
*return_bi = bi;
}
bi = bi2;
}
/* fail any reads if this device is non-operational and
* the data has not reached the cache yet.
*/
if (!test_bit(R5_Wantfill, &sh->dev[i].flags) &&
(!test_bit(R5_Insync, &sh->dev[i].flags) ||
test_bit(R5_ReadError, &sh->dev[i].flags))) {
bi = sh->dev[i].toread;
sh->dev[i].toread = NULL;
if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
wake_up(&conf->wait_for_overlap);
if (bi) s->to_read--;
while (bi && bi->bi_sector <
sh->dev[i].sector + STRIPE_SECTORS) {
struct bio *nextbi =
r5_next_bio(bi, sh->dev[i].sector);
clear_bit(BIO_UPTODATE, &bi->bi_flags);
if (!raid5_dec_bi_phys_segments(bi)) {
bi->bi_next = *return_bi;
*return_bi = bi;
}
bi = nextbi;
}
}
spin_unlock_irq(&conf->device_lock);
if (bitmap_end)
bitmap_endwrite(conf->mddev->bitmap, sh->sector,
STRIPE_SECTORS, 0, 0);
}
if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
if (atomic_dec_and_test(&conf->pending_full_writes))
md_wakeup_thread(conf->mddev->thread);
}
/* fetch_block5 - checks the given member device to see if its data needs
* to be read or computed to satisfy a request.
*
* Returns 1 when no more member devices need to be checked, otherwise returns
* 0 to tell the loop in handle_stripe_fill5 to continue
*/
static int fetch_block5(struct stripe_head *sh, struct stripe_head_state *s,
int disk_idx, int disks)
{
struct r5dev *dev = &sh->dev[disk_idx];
struct r5dev *failed_dev = &sh->dev[s->failed_num];
/* is the data in this block needed, and can we get it? */
if (!test_bit(R5_LOCKED, &dev->flags) &&
!test_bit(R5_UPTODATE, &dev->flags) &&
(dev->toread ||
(dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)) ||
s->syncing || s->expanding ||
(s->failed &&
(failed_dev->toread ||
(failed_dev->towrite &&
!test_bit(R5_OVERWRITE, &failed_dev->flags)))))) {
/* We would like to get this block, possibly by computing it,
* otherwise read it if the backing disk is insync
*/
if ((s->uptodate == disks - 1) &&
(s->failed && disk_idx == s->failed_num)) {
set_bit(STRIPE_COMPUTE_RUN, &sh->state);
set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
set_bit(R5_Wantcompute, &dev->flags);
sh->ops.target = disk_idx;
s->req_compute = 1;
/* Careful: from this point on 'uptodate' is in the eye
* of raid5_run_ops which services 'compute' operations
* before writes. R5_Wantcompute flags a block that will
* be R5_UPTODATE by the time it is needed for a
* subsequent operation.
*/
s->uptodate++;
return 1; /* uptodate + compute == disks */
} else if (test_bit(R5_Insync, &dev->flags)) {
set_bit(R5_LOCKED, &dev->flags);
set_bit(R5_Wantread, &dev->flags);
s->locked++;
pr_debug("Reading block %d (sync=%d)\n", disk_idx,
s->syncing);
}
}
return 0;
}
/**
* handle_stripe_fill5 - read or compute data to satisfy pending requests.
*/
static void handle_stripe_fill5(struct stripe_head *sh,
struct stripe_head_state *s, int disks)
{
int i;
/* look for blocks to read/compute, skip this if a compute
* is already in flight, or if the stripe contents are in the
* midst of changing due to a write
*/
if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state &&
!sh->reconstruct_state)
for (i = disks; i--; )
if (fetch_block5(sh, s, i, disks))
break;
set_bit(STRIPE_HANDLE, &sh->state);
}
static void handle_stripe_fill6(struct stripe_head *sh,
struct stripe_head_state *s, struct r6_state *r6s,
int disks)
{
int i;
for (i = disks; i--; ) {
struct r5dev *dev = &sh->dev[i];
if (!test_bit(R5_LOCKED, &dev->flags) &&
!test_bit(R5_UPTODATE, &dev->flags) &&
(dev->toread || (dev->towrite &&
!test_bit(R5_OVERWRITE, &dev->flags)) ||
s->syncing || s->expanding ||
(s->failed >= 1 &&
(sh->dev[r6s->failed_num[0]].toread ||
s->to_write)) ||
(s->failed >= 2 &&
(sh->dev[r6s->failed_num[1]].toread ||
s->to_write)))) {
/* we would like to get this block, possibly
* by computing it, but we might not be able to
*/
if ((s->uptodate == disks - 1) &&
(s->failed && (i == r6s->failed_num[0] ||
i == r6s->failed_num[1]))) {
pr_debug("Computing stripe %llu block %d\n",
(unsigned long long)sh->sector, i);
compute_block_1(sh, i, 0);
s->uptodate++;
} else if ( s->uptodate == disks-2 && s->failed >= 2 ) {
/* Computing 2-failure is *very* expensive; only
* do it if failed >= 2
*/
int other;
for (other = disks; other--; ) {
if (other == i)
continue;
if (!test_bit(R5_UPTODATE,
&sh->dev[other].flags))
break;
}
BUG_ON(other < 0);
pr_debug("Computing stripe %llu blocks %d,%d\n",
(unsigned long long)sh->sector,
i, other);
compute_block_2(sh, i, other);
s->uptodate += 2;
} else if (test_bit(R5_Insync, &dev->flags)) {
set_bit(R5_LOCKED, &dev->flags);
set_bit(R5_Wantread, &dev->flags);
s->locked++;
pr_debug("Reading block %d (sync=%d)\n",
i, s->syncing);
}
}
}
set_bit(STRIPE_HANDLE, &sh->state);
}
/* handle_stripe_clean_event
* any written block on an uptodate or failed drive can be returned.
* Note that if we 'wrote' to a failed drive, it will be UPTODATE, but
* never LOCKED, so we don't need to test 'failed' directly.
*/
static void handle_stripe_clean_event(raid5_conf_t *conf,
struct stripe_head *sh, int disks, struct bio **return_bi)
{
int i;
struct r5dev *dev;
for (i = disks; i--; )
if (sh->dev[i].written) {
dev = &sh->dev[i];
if (!test_bit(R5_LOCKED, &dev->flags) &&
test_bit(R5_UPTODATE, &dev->flags)) {
/* We can return any write requests */
struct bio *wbi, *wbi2;
int bitmap_end = 0;
pr_debug("Return write for disc %d\n", i);
spin_lock_irq(&conf->device_lock);
wbi = dev->written;
dev->written = NULL;
while (wbi && wbi->bi_sector <
dev->sector + STRIPE_SECTORS) {
wbi2 = r5_next_bio(wbi, dev->sector);
if (!raid5_dec_bi_phys_segments(wbi)) {
md_write_end(conf->mddev);
wbi->bi_next = *return_bi;
*return_bi = wbi;
}
wbi = wbi2;
}
if (dev->towrite == NULL)
bitmap_end = 1;
spin_unlock_irq(&conf->device_lock);
if (bitmap_end)
bitmap_endwrite(conf->mddev->bitmap,
sh->sector,
STRIPE_SECTORS,
!test_bit(STRIPE_DEGRADED, &sh->state),
0);
}
}
if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
if (atomic_dec_and_test(&conf->pending_full_writes))
md_wakeup_thread(conf->mddev->thread);
}
static void handle_stripe_dirtying5(raid5_conf_t *conf,
struct stripe_head *sh, struct stripe_head_state *s, int disks)
{
int rmw = 0, rcw = 0, i;
for (i = disks; i--; ) {
/* would I have to read this buffer for read_modify_write */
struct r5dev *dev = &sh->dev[i];
if ((dev->towrite || i == sh->pd_idx) &&
!test_bit(R5_LOCKED, &dev->flags) &&
!(test_bit(R5_UPTODATE, &dev->flags) ||
test_bit(R5_Wantcompute, &dev->flags))) {
if (test_bit(R5_Insync, &dev->flags))
rmw++;
else
rmw += 2*disks; /* cannot read it */
}
/* Would I have to read this buffer for reconstruct_write */
if (!test_bit(R5_OVERWRITE, &dev->flags) && i != sh->pd_idx &&
!test_bit(R5_LOCKED, &dev->flags) &&
!(test_bit(R5_UPTODATE, &dev->flags) ||
test_bit(R5_Wantcompute, &dev->flags))) {
if (test_bit(R5_Insync, &dev->flags)) rcw++;
else
rcw += 2*disks;
}
}
pr_debug("for sector %llu, rmw=%d rcw=%d\n",
(unsigned long long)sh->sector, rmw, rcw);
set_bit(STRIPE_HANDLE, &sh->state);
if (rmw < rcw && rmw > 0)
/* prefer read-modify-write, but need to get some data */
for (i = disks; i--; ) {
struct r5dev *dev = &sh->dev[i];
if ((dev->towrite || i == sh->pd_idx) &&
!test_bit(R5_LOCKED, &dev->flags) &&
!(test_bit(R5_UPTODATE, &dev->flags) ||
test_bit(R5_Wantcompute, &dev->flags)) &&
test_bit(R5_Insync, &dev->flags)) {
if (
test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
pr_debug("Read_old block "
"%d for r-m-w\n", i);
set_bit(R5_LOCKED, &dev->flags);
set_bit(R5_Wantread, &dev->flags);
s->locked++;
} else {
set_bit(STRIPE_DELAYED, &sh->state);
set_bit(STRIPE_HANDLE, &sh->state);
}
}
}
if (rcw <= rmw && rcw > 0)
/* want reconstruct write, but need to get some data */
for (i = disks; i--; ) {
struct r5dev *dev = &sh->dev[i];
if (!test_bit(R5_OVERWRITE, &dev->flags) &&
i != sh->pd_idx &&
!test_bit(R5_LOCKED, &dev->flags) &&
!(test_bit(R5_UPTODATE, &dev->flags) ||
test_bit(R5_Wantcompute, &dev->flags)) &&
test_bit(R5_Insync, &dev->flags)) {
if (
test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
pr_debug("Read_old block "
"%d for Reconstruct\n", i);
set_bit(R5_LOCKED, &dev->flags);
set_bit(R5_Wantread, &dev->flags);
s->locked++;
} else {
set_bit(STRIPE_DELAYED, &sh->state);
set_bit(STRIPE_HANDLE, &sh->state);
}
}
}
/* now if nothing is locked, and if we have enough data,
* we can start a write request
*/
/* since handle_stripe can be called at any time we need to handle the
* case where a compute block operation has been submitted and then a
* subsequent call wants to start a write request. raid5_run_ops only
* handles the case where compute block and postxor are requested
* simultaneously. If this is not the case then new writes need to be
* held off until the compute completes.
*/
if ((s->req_compute || !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) &&
(s->locked == 0 && (rcw == 0 || rmw == 0) &&
!test_bit(STRIPE_BIT_DELAY, &sh->state)))
schedule_reconstruction5(sh, s, rcw == 0, 0);
}
static void handle_stripe_dirtying6(raid5_conf_t *conf,
struct stripe_head *sh, struct stripe_head_state *s,
struct r6_state *r6s, int disks)
{
int rcw = 0, must_compute = 0, pd_idx = sh->pd_idx, i;
int qd_idx = sh->qd_idx;
for (i = disks; i--; ) {
struct r5dev *dev = &sh->dev[i];
/* Would I have to read this buffer for reconstruct_write */
if (!test_bit(R5_OVERWRITE, &dev->flags)
&& i != pd_idx && i != qd_idx
&& (!test_bit(R5_LOCKED, &dev->flags)
) &&
!test_bit(R5_UPTODATE, &dev->flags)) {
if (test_bit(R5_Insync, &dev->flags)) rcw++;
else {
pr_debug("raid6: must_compute: "
"disk %d flags=%#lx\n", i, dev->flags);
must_compute++;
}
}
}
pr_debug("for sector %llu, rcw=%d, must_compute=%d\n",
(unsigned long long)sh->sector, rcw, must_compute);
set_bit(STRIPE_HANDLE, &sh->state);
if (rcw > 0)
/* want reconstruct write, but need to get some data */
for (i = disks; i--; ) {
struct r5dev *dev = &sh->dev[i];
if (!test_bit(R5_OVERWRITE, &dev->flags)
&& !(s->failed == 0 && (i == pd_idx || i == qd_idx))
&& !test_bit(R5_LOCKED, &dev->flags) &&
!test_bit(R5_UPTODATE, &dev->flags) &&
test_bit(R5_Insync, &dev->flags)) {
if (
test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
pr_debug("Read_old stripe %llu "
"block %d for Reconstruct\n",
(unsigned long long)sh->sector, i);
set_bit(R5_LOCKED, &dev->flags);
set_bit(R5_Wantread, &dev->flags);
s->locked++;
} else {
pr_debug("Request delayed stripe %llu "
"block %d for Reconstruct\n",
(unsigned long long)sh->sector, i);
set_bit(STRIPE_DELAYED, &sh->state);
set_bit(STRIPE_HANDLE, &sh->state);
}
}
}
/* now if nothing is locked, and if we have enough data, we can start a
* write request
*/
if (s->locked == 0 && rcw == 0 &&
!test_bit(STRIPE_BIT_DELAY, &sh->state)) {
if (must_compute > 0) {
/* We have failed blocks and need to compute them */
switch (s->failed) {
case 0:
BUG();
case 1:
compute_block_1(sh, r6s->failed_num[0], 0);
break;
case 2:
compute_block_2(sh, r6s->failed_num[0],
r6s->failed_num[1]);
break;
default: /* This request should have been failed? */
BUG();
}
}
pr_debug("Computing parity for stripe %llu\n",
(unsigned long long)sh->sector);
compute_parity6(sh, RECONSTRUCT_WRITE);
/* now every locked buffer is ready to be written */
for (i = disks; i--; )
if (test_bit(R5_LOCKED, &sh->dev[i].flags)) {
pr_debug("Writing stripe %llu block %d\n",
(unsigned long long)sh->sector, i);
s->locked++;
set_bit(R5_Wantwrite, &sh->dev[i].flags);
}
if (s->locked == disks)
if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state))
atomic_inc(&conf->pending_full_writes);
/* after a RECONSTRUCT_WRITE, the stripe MUST be in-sync */
set_bit(STRIPE_INSYNC, &sh->state);
if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
atomic_dec(&conf->preread_active_stripes);
if (atomic_read(&conf->preread_active_stripes) <
IO_THRESHOLD)
md_wakeup_thread(conf->mddev->thread);
}
}
}
static void handle_parity_checks5(raid5_conf_t *conf, struct stripe_head *sh,
struct stripe_head_state *s, int disks)
{
struct r5dev *dev = NULL;
set_bit(STRIPE_HANDLE, &sh->state);
switch (sh->check_state) {
case check_state_idle:
/* start a new check operation if there are no failures */
if (s->failed == 0) {
BUG_ON(s->uptodate != disks);
sh->check_state = check_state_run;
set_bit(STRIPE_OP_CHECK, &s->ops_request);
clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
s->uptodate--;
break;
}
dev = &sh->dev[s->failed_num];
/* fall through */
case check_state_compute_result:
sh->check_state = check_state_idle;
if (!dev)
dev = &sh->dev[sh->pd_idx];
/* check that a write has not made the stripe insync */
if (test_bit(STRIPE_INSYNC, &sh->state))
break;
/* either failed parity check, or recovery is happening */
BUG_ON(!test_bit(R5_UPTODATE, &dev->flags));
BUG_ON(s->uptodate != disks);
set_bit(R5_LOCKED, &dev->flags);
s->locked++;
set_bit(R5_Wantwrite, &dev->flags);
clear_bit(STRIPE_DEGRADED, &sh->state);
set_bit(STRIPE_INSYNC, &sh->state);
break;
case check_state_run:
break; /* we will be called again upon completion */
case check_state_check_result:
sh->check_state = check_state_idle;
/* if a failure occurred during the check operation, leave
* STRIPE_INSYNC not set and let the stripe be handled again
*/
if (s->failed)
break;
/* handle a successful check operation, if parity is correct
* we are done. Otherwise update the mismatch count and repair
* parity if !MD_RECOVERY_CHECK
*/
if (sh->ops.zero_sum_result == 0)
/* parity is correct (on disc,
* not in buffer any more)
*/
set_bit(STRIPE_INSYNC, &sh->state);
else {
conf->mddev->resync_mismatches += STRIPE_SECTORS;
if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))
/* don't try to repair!! */
set_bit(STRIPE_INSYNC, &sh->state);
else {
sh->check_state = check_state_compute_run;
set_bit(STRIPE_COMPUTE_RUN, &sh->state);
set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
set_bit(R5_Wantcompute,
&sh->dev[sh->pd_idx].flags);
sh->ops.target = sh->pd_idx;
s->uptodate++;
}
}
break;
case check_state_compute_run:
break;
default:
printk(KERN_ERR "%s: unknown check_state: %d sector: %llu\n",
__func__, sh->check_state,
(unsigned long long) sh->sector);
BUG();
}
}
static void handle_parity_checks6(raid5_conf_t *conf, struct stripe_head *sh,
struct stripe_head_state *s,
struct r6_state *r6s, struct page *tmp_page,
int disks)
{
int update_p = 0, update_q = 0;
struct r5dev *dev;
int pd_idx = sh->pd_idx;
int qd_idx = sh->qd_idx;
set_bit(STRIPE_HANDLE, &sh->state);
BUG_ON(s->failed > 2);
BUG_ON(s->uptodate < disks);
/* Want to check and possibly repair P and Q.
* However there could be one 'failed' device, in which
* case we can only check one of them, possibly using the
* other to generate missing data
*/
/* If !tmp_page, we cannot do the calculations,
* but as we have set STRIPE_HANDLE, we will soon be called
* by stripe_handle with a tmp_page - just wait until then.
*/
if (tmp_page) {
if (s->failed == r6s->q_failed) {
/* The only possible failed device holds 'Q', so it
* makes sense to check P (If anything else were failed,
* we would have used P to recreate it).
*/
compute_block_1(sh, pd_idx, 1);
if (!page_is_zero(sh->dev[pd_idx].page)) {
compute_block_1(sh, pd_idx, 0);
update_p = 1;
}
}
if (!r6s->q_failed && s->failed < 2) {
/* q is not failed, and we didn't use it to generate
* anything, so it makes sense to check it
*/
memcpy(page_address(tmp_page),
page_address(sh->dev[qd_idx].page),
STRIPE_SIZE);
compute_parity6(sh, UPDATE_PARITY);
if (memcmp(page_address(tmp_page),
page_address(sh->dev[qd_idx].page),
STRIPE_SIZE) != 0) {
clear_bit(STRIPE_INSYNC, &sh->state);
update_q = 1;
}
}
if (update_p || update_q) {
conf->mddev->resync_mismatches += STRIPE_SECTORS;
if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))
/* don't try to repair!! */
update_p = update_q = 0;
}
/* now write out any block on a failed drive,
* or P or Q if they need it
*/
if (s->failed == 2) {
dev = &sh->dev[r6s->failed_num[1]];
s->locked++;
set_bit(R5_LOCKED, &dev->flags);
set_bit(R5_Wantwrite, &dev->flags);
}
if (s->failed >= 1) {
dev = &sh->dev[r6s->failed_num[0]];
s->locked++;
set_bit(R5_LOCKED, &dev->flags);
set_bit(R5_Wantwrite, &dev->flags);
}
if (update_p) {
dev = &sh->dev[pd_idx];
s->locked++;
set_bit(R5_LOCKED, &dev->flags);
set_bit(R5_Wantwrite, &dev->flags);
}
if (update_q) {
dev = &sh->dev[qd_idx];
s->locked++;
set_bit(R5_LOCKED, &dev->flags);
set_bit(R5_Wantwrite, &dev->flags);
}
clear_bit(STRIPE_DEGRADED, &sh->state);
set_bit(STRIPE_INSYNC, &sh->state);
}
}
static void handle_stripe_expansion(raid5_conf_t *conf, struct stripe_head *sh,
struct r6_state *r6s)
{
int i;
/* We have read all the blocks in this stripe and now we need to
* copy some of them into a target stripe for expand.
*/
struct dma_async_tx_descriptor *tx = NULL;
clear_bit(STRIPE_EXPAND_SOURCE, &sh->state);
for (i = 0; i < sh->disks; i++)
if (i != sh->pd_idx && i != sh->qd_idx) {
int dd_idx, j;
struct stripe_head *sh2;
sector_t bn = compute_blocknr(sh, i, 1);
sector_t s = raid5_compute_sector(conf, bn, 0,
&dd_idx, NULL);
sh2 = get_active_stripe(conf, s, 0, 1, 1);
if (sh2 == NULL)
/* so far only the early blocks of this stripe
* have been requested. When later blocks
* get requested, we will try again
*/
continue;
if (!test_bit(STRIPE_EXPANDING, &sh2->state) ||
test_bit(R5_Expanded, &sh2->dev[dd_idx].flags)) {
/* must have already done this block */
release_stripe(sh2);
continue;
}
/* place all the copies on one channel */
tx = async_memcpy(sh2->dev[dd_idx].page,
sh->dev[i].page, 0, 0, STRIPE_SIZE,
ASYNC_TX_DEP_ACK, tx, NULL, NULL);
set_bit(R5_Expanded, &sh2->dev[dd_idx].flags);
set_bit(R5_UPTODATE, &sh2->dev[dd_idx].flags);
for (j = 0; j < conf->raid_disks; j++)
if (j != sh2->pd_idx &&
(!r6s || j != sh2->qd_idx) &&
!test_bit(R5_Expanded, &sh2->dev[j].flags))
break;
if (j == conf->raid_disks) {
set_bit(STRIPE_EXPAND_READY, &sh2->state);
set_bit(STRIPE_HANDLE, &sh2->state);
}
release_stripe(sh2);
}
/* done submitting copies, wait for them to complete */
if (tx) {
async_tx_ack(tx);
dma_wait_for_async_tx(tx);
}
}
/*
* handle_stripe - do things to a stripe.
*
* We lock the stripe and then examine the state of various bits
* to see what needs to be done.
* Possible results:
* return some read request which now have data
* return some write requests which are safely on disc
* schedule a read on some buffers
* schedule a write of some buffers
* return confirmation of parity correctness
*
* buffers are taken off read_list or write_list, and bh_cache buffers
* get BH_Lock set before the stripe lock is released.
*
*/
static bool handle_stripe5(struct stripe_head *sh)
{
raid5_conf_t *conf = sh->raid_conf;
int disks = sh->disks, i;
struct bio *return_bi = NULL;
struct stripe_head_state s;
struct r5dev *dev;
mdk_rdev_t *blocked_rdev = NULL;
int prexor;
memset(&s, 0, sizeof(s));
pr_debug("handling stripe %llu, state=%#lx cnt=%d, pd_idx=%d check:%d "
"reconstruct:%d\n", (unsigned long long)sh->sector, sh->state,
atomic_read(&sh->count), sh->pd_idx, sh->check_state,
sh->reconstruct_state);
spin_lock(&sh->lock);
clear_bit(STRIPE_HANDLE, &sh->state);
clear_bit(STRIPE_DELAYED, &sh->state);
s.syncing = test_bit(STRIPE_SYNCING, &sh->state);
s.expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state);
s.expanded = test_bit(STRIPE_EXPAND_READY, &sh->state);
/* Now to look around and see what can be done */
rcu_read_lock();
for (i=disks; i--; ) {
mdk_rdev_t *rdev;
struct r5dev *dev = &sh->dev[i];
clear_bit(R5_Insync, &dev->flags);
pr_debug("check %d: state 0x%lx toread %p read %p write %p "
"written %p\n", i, dev->flags, dev->toread, dev->read,
dev->towrite, dev->written);
/* maybe we can request a biofill operation
*
* new wantfill requests are only permitted while
* ops_complete_biofill is guaranteed to be inactive
*/
if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread &&
!test_bit(STRIPE_BIOFILL_RUN, &sh->state))
set_bit(R5_Wantfill, &dev->flags);
/* now count some things */
if (test_bit(R5_LOCKED, &dev->flags)) s.locked++;
if (test_bit(R5_UPTODATE, &dev->flags)) s.uptodate++;
if (test_bit(R5_Wantcompute, &dev->flags)) s.compute++;
if (test_bit(R5_Wantfill, &dev->flags))
s.to_fill++;
else if (dev->toread)
s.to_read++;
if (dev->towrite) {
s.to_write++;
if (!test_bit(R5_OVERWRITE, &dev->flags))
s.non_overwrite++;
}
if (dev->written)
s.written++;
rdev = rcu_dereference(conf->disks[i].rdev);
if (blocked_rdev == NULL &&
rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
blocked_rdev = rdev;
atomic_inc(&rdev->nr_pending);
}
if (!rdev || !test_bit(In_sync, &rdev->flags)) {
/* The ReadError flag will just be confusing now */
clear_bit(R5_ReadError, &dev->flags);
clear_bit(R5_ReWrite, &dev->flags);
}
if (!rdev || !test_bit(In_sync, &rdev->flags)
|| test_bit(R5_ReadError, &dev->flags)) {
s.failed++;
s.failed_num = i;
} else
set_bit(R5_Insync, &dev->flags);
}
rcu_read_unlock();
if (unlikely(blocked_rdev)) {
if (s.syncing || s.expanding || s.expanded ||
s.to_write || s.written) {
set_bit(STRIPE_HANDLE, &sh->state);
goto unlock;
}
/* There is nothing for the blocked_rdev to block */
rdev_dec_pending(blocked_rdev, conf->mddev);
blocked_rdev = NULL;
}
if (s.to_fill && !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) {
set_bit(STRIPE_OP_BIOFILL, &s.ops_request);
set_bit(STRIPE_BIOFILL_RUN, &sh->state);
}
pr_debug("locked=%d uptodate=%d to_read=%d"
" to_write=%d failed=%d failed_num=%d\n",
s.locked, s.uptodate, s.to_read, s.to_write,
s.failed, s.failed_num);
/* check if the array has lost two devices and, if so, some requests might
* need to be failed
*/
if (s.failed > 1 && s.to_read+s.to_write+s.written)
handle_failed_stripe(conf, sh, &s, disks, &return_bi);
if (s.failed > 1 && s.syncing) {
md_done_sync(conf->mddev, STRIPE_SECTORS,0);
clear_bit(STRIPE_SYNCING, &sh->state);
s.syncing = 0;
}
/* might be able to return some write requests if the parity block
* is safe, or on a failed drive
*/
dev = &sh->dev[sh->pd_idx];
if ( s.written &&
((test_bit(R5_Insync, &dev->flags) &&
!test_bit(R5_LOCKED, &dev->flags) &&
test_bit(R5_UPTODATE, &dev->flags)) ||
(s.failed == 1 && s.failed_num == sh->pd_idx)))
handle_stripe_clean_event(conf, sh, disks, &return_bi);
/* Now we might consider reading some blocks, either to check/generate
* parity, or to satisfy requests
* or to load a block that is being partially written.
*/
if (s.to_read || s.non_overwrite ||
(s.syncing && (s.uptodate + s.compute < disks)) || s.expanding)
handle_stripe_fill5(sh, &s, disks);
/* Now we check to see if any write operations have recently
* completed
*/
prexor = 0;
if (sh->reconstruct_state == reconstruct_state_prexor_drain_result)
prexor = 1;
if (sh->reconstruct_state == reconstruct_state_drain_result ||
sh->reconstruct_state == reconstruct_state_prexor_drain_result) {
sh->reconstruct_state = reconstruct_state_idle;
/* All the 'written' buffers and the parity block are ready to
* be written back to disk
*/
BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags));
for (i = disks; i--; ) {
dev = &sh->dev[i];
if (test_bit(R5_LOCKED, &dev->flags) &&
(i == sh->pd_idx || dev->written)) {
pr_debug("Writing block %d\n", i);
set_bit(R5_Wantwrite, &dev->flags);
if (prexor)
continue;
if (!test_bit(R5_Insync, &dev->flags) ||
(i == sh->pd_idx && s.failed == 0))
set_bit(STRIPE_INSYNC, &sh->state);
}
}
if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
atomic_dec(&conf->preread_active_stripes);
if (atomic_read(&conf->preread_active_stripes) <
IO_THRESHOLD)
md_wakeup_thread(conf->mddev->thread);
}
}
/* Now to consider new write requests and what else, if anything
* should be read. We do not handle new writes when:
* 1/ A 'write' operation (copy+xor) is already in flight.
* 2/ A 'check' operation is in flight, as it may clobber the parity
* block.
*/
if (s.to_write && !sh->reconstruct_state && !sh->check_state)
handle_stripe_dirtying5(conf, sh, &s, disks);
/* maybe we need to check and possibly fix the parity for this stripe
* Any reads will already have been scheduled, so we just see if enough
* data is available. The parity check is held off while parity
* dependent operations are in flight.
*/
if (sh->check_state ||
(s.syncing && s.locked == 0 &&
!test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
!test_bit(STRIPE_INSYNC, &sh->state)))
handle_parity_checks5(conf, sh, &s, disks);
if (s.syncing && s.locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) {
md_done_sync(conf->mddev, STRIPE_SECTORS,1);
clear_bit(STRIPE_SYNCING, &sh->state);
}
/* If the failed drive is just a ReadError, then we might need to progress
* the repair/check process
*/
if (s.failed == 1 && !conf->mddev->ro &&
test_bit(R5_ReadError, &sh->dev[s.failed_num].flags)
&& !test_bit(R5_LOCKED, &sh->dev[s.failed_num].flags)
&& test_bit(R5_UPTODATE, &sh->dev[s.failed_num].flags)
) {
dev = &sh->dev[s.failed_num];
if (!test_bit(R5_ReWrite, &dev->flags)) {
set_bit(R5_Wantwrite, &dev->flags);
set_bit(R5_ReWrite, &dev->flags);
set_bit(R5_LOCKED, &dev->flags);
s.locked++;
} else {
/* let's read it back */
set_bit(R5_Wantread, &dev->flags);
set_bit(R5_LOCKED, &dev->flags);
s.locked++;
}
}
/* Finish reconstruct operations initiated by the expansion process */
if (sh->reconstruct_state == reconstruct_state_result) {
struct stripe_head *sh2
= get_active_stripe(conf, sh->sector, 1, 1, 1);
if (sh2 && test_bit(STRIPE_EXPAND_SOURCE, &sh2->state)) {
/* sh cannot be written until sh2 has been read.
* so arrange for sh to be delayed a little
*/
set_bit(STRIPE_DELAYED, &sh->state);
set_bit(STRIPE_HANDLE, &sh->state);
if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE,
&sh2->state))
atomic_inc(&conf->preread_active_stripes);
release_stripe(sh2);
goto unlock;
}
if (sh2)
release_stripe(sh2);
sh->reconstruct_state = reconstruct_state_idle;
clear_bit(STRIPE_EXPANDING, &sh->state);
for (i = conf->raid_disks; i--; ) {
set_bit(R5_Wantwrite, &sh->dev[i].flags);
set_bit(R5_LOCKED, &sh->dev[i].flags);
s.locked++;
}
}
if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state) &&
!sh->reconstruct_state) {
/* Need to write out all blocks after computing parity */
sh->disks = conf->raid_disks;
stripe_set_idx(sh->sector, conf, 0, sh);
schedule_reconstruction5(sh, &s, 1, 1);
} else if (s.expanded && !sh->reconstruct_state && s.locked == 0) {
clear_bit(STRIPE_EXPAND_READY, &sh->state);
atomic_dec(&conf->reshape_stripes);
wake_up(&conf->wait_for_overlap);
md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
}
if (s.expanding && s.locked == 0 &&
!test_bit(STRIPE_COMPUTE_RUN, &sh->state))
handle_stripe_expansion(conf, sh, NULL);
unlock:
spin_unlock(&sh->lock);
/* wait for this device to become unblocked */
if (unlikely(blocked_rdev))
md_wait_for_blocked_rdev(blocked_rdev, conf->mddev);
if (s.ops_request)
raid5_run_ops(sh, s.ops_request);
ops_run_io(sh, &s);
return_io(return_bi);
return blocked_rdev == NULL;
}
static bool handle_stripe6(struct stripe_head *sh, struct page *tmp_page)
{
raid5_conf_t *conf = sh->raid_conf;
int disks = sh->disks;
struct bio *return_bi = NULL;
int i, pd_idx = sh->pd_idx, qd_idx = sh->qd_idx;
struct stripe_head_state s;
struct r6_state r6s;
struct r5dev *dev, *pdev, *qdev;
mdk_rdev_t *blocked_rdev = NULL;
pr_debug("handling stripe %llu, state=%#lx cnt=%d, "
"pd_idx=%d, qd_idx=%d\n",
(unsigned long long)sh->sector, sh->state,
atomic_read(&sh->count), pd_idx, qd_idx);
memset(&s, 0, sizeof(s));
spin_lock(&sh->lock);
clear_bit(STRIPE_HANDLE, &sh->state);
clear_bit(STRIPE_DELAYED, &sh->state);
s.syncing = test_bit(STRIPE_SYNCING, &sh->state);
s.expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state);
s.expanded = test_bit(STRIPE_EXPAND_READY, &sh->state);
/* Now to look around and see what can be done */
rcu_read_lock();
for (i=disks; i--; ) {
mdk_rdev_t *rdev;
dev = &sh->dev[i];
clear_bit(R5_Insync, &dev->flags);
pr_debug("check %d: state 0x%lx read %p write %p written %p\n",
i, dev->flags, dev->toread, dev->towrite, dev->written);
/* maybe we can reply to a read */
if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread) {
struct bio *rbi, *rbi2;
pr_debug("Return read for disc %d\n", i);
spin_lock_irq(&conf->device_lock);
rbi = dev->toread;
dev->toread = NULL;
if (test_and_clear_bit(R5_Overlap, &dev->flags))
wake_up(&conf->wait_for_overlap);
spin_unlock_irq(&conf->device_lock);
while (rbi && rbi->bi_sector < dev->sector + STRIPE_SECTORS) {
copy_data(0, rbi, dev->page, dev->sector);
rbi2 = r5_next_bio(rbi, dev->sector);
spin_lock_irq(&conf->device_lock);
if (!raid5_dec_bi_phys_segments(rbi)) {
rbi->bi_next = return_bi;
return_bi = rbi;
}
spin_unlock_irq(&conf->device_lock);
rbi = rbi2;
}
}
/* now count some things */
if (test_bit(R5_LOCKED, &dev->flags)) s.locked++;
if (test_bit(R5_UPTODATE, &dev->flags)) s.uptodate++;
if (dev->toread)
s.to_read++;
if (dev->towrite) {
s.to_write++;
if (!test_bit(R5_OVERWRITE, &dev->flags))
s.non_overwrite++;
}
if (dev->written)
s.written++;
rdev = rcu_dereference(conf->disks[i].rdev);
if (blocked_rdev == NULL &&
rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
blocked_rdev = rdev;
atomic_inc(&rdev->nr_pending);
}
if (!rdev || !test_bit(In_sync, &rdev->flags)) {
/* The ReadError flag will just be confusing now */
clear_bit(R5_ReadError, &dev->flags);
clear_bit(R5_ReWrite, &dev->flags);
}
if (!rdev || !test_bit(In_sync, &rdev->flags)
|| test_bit(R5_ReadError, &dev->flags)) {
if (s.failed < 2)
r6s.failed_num[s.failed] = i;
s.failed++;
} else
set_bit(R5_Insync, &dev->flags);
}
rcu_read_unlock();
if (unlikely(blocked_rdev)) {
if (s.syncing || s.expanding || s.expanded ||
s.to_write || s.written) {
set_bit(STRIPE_HANDLE, &sh->state);
goto unlock;
}
/* There is nothing for the blocked_rdev to block */
rdev_dec_pending(blocked_rdev, conf->mddev);
blocked_rdev = NULL;
}
pr_debug("locked=%d uptodate=%d to_read=%d"
" to_write=%d failed=%d failed_num=%d,%d\n",
s.locked, s.uptodate, s.to_read, s.to_write, s.failed,
r6s.failed_num[0], r6s.failed_num[1]);
/* check if the array has lost >2 devices and, if so, some requests
* might need to be failed
*/
if (s.failed > 2 && s.to_read+s.to_write+s.written)
handle_failed_stripe(conf, sh, &s, disks, &return_bi);
if (s.failed > 2 && s.syncing) {
md_done_sync(conf->mddev, STRIPE_SECTORS,0);
clear_bit(STRIPE_SYNCING, &sh->state);
s.syncing = 0;
}
/*
* might be able to return some write requests if the parity blocks
* are safe, or on a failed drive
*/
pdev = &sh->dev[pd_idx];
r6s.p_failed = (s.failed >= 1 && r6s.failed_num[0] == pd_idx)
|| (s.failed >= 2 && r6s.failed_num[1] == pd_idx);
qdev = &sh->dev[qd_idx];
r6s.q_failed = (s.failed >= 1 && r6s.failed_num[0] == qd_idx)
|| (s.failed >= 2 && r6s.failed_num[1] == qd_idx);
if ( s.written &&
( r6s.p_failed || ((test_bit(R5_Insync, &pdev->flags)
&& !test_bit(R5_LOCKED, &pdev->flags)
&& test_bit(R5_UPTODATE, &pdev->flags)))) &&
( r6s.q_failed || ((test_bit(R5_Insync, &qdev->flags)
&& !test_bit(R5_LOCKED, &qdev->flags)
&& test_bit(R5_UPTODATE, &qdev->flags)))))
handle_stripe_clean_event(conf, sh, disks, &return_bi);
/* Now we might consider reading some blocks, either to check/generate
* parity, or to satisfy requests
* or to load a block that is being partially written.
*/
if (s.to_read || s.non_overwrite || (s.to_write && s.failed) ||
(s.syncing && (s.uptodate < disks)) || s.expanding)
handle_stripe_fill6(sh, &s, &r6s, disks);
/* now to consider writing and what else, if anything should be read */
if (s.to_write)
handle_stripe_dirtying6(conf, sh, &s, &r6s, disks);
/* maybe we need to check and possibly fix the parity for this stripe
* Any reads will already have been scheduled, so we just see if enough
* data is available
*/
if (s.syncing && s.locked == 0 && !test_bit(STRIPE_INSYNC, &sh->state))
handle_parity_checks6(conf, sh, &s, &r6s, tmp_page, disks);
if (s.syncing && s.locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) {
md_done_sync(conf->mddev, STRIPE_SECTORS,1);
clear_bit(STRIPE_SYNCING, &sh->state);
}
/* If the failed drives are just a ReadError, then we might need
* to progress the repair/check process
*/
if (s.failed <= 2 && !conf->mddev->ro)
for (i = 0; i < s.failed; i++) {
dev = &sh->dev[r6s.failed_num[i]];
if (test_bit(R5_ReadError, &dev->flags)
&& !test_bit(R5_LOCKED, &dev->flags)
&& test_bit(R5_UPTODATE, &dev->flags)
) {
if (!test_bit(R5_ReWrite, &dev->flags)) {
set_bit(R5_Wantwrite, &dev->flags);
set_bit(R5_ReWrite, &dev->flags);
set_bit(R5_LOCKED, &dev->flags);
} else {
/* let's read it back */
set_bit(R5_Wantread, &dev->flags);
set_bit(R5_LOCKED, &dev->flags);
}
}
}
if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state)) {
struct stripe_head *sh2
= get_active_stripe(conf, sh->sector, 1, 1, 1);
if (sh2 && test_bit(STRIPE_EXPAND_SOURCE, &sh2->state)) {
/* sh cannot be written until sh2 has been read.
* so arrange for sh to be delayed a little
*/
set_bit(STRIPE_DELAYED, &sh->state);
set_bit(STRIPE_HANDLE, &sh->state);
if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE,
&sh2->state))
atomic_inc(&conf->preread_active_stripes);
release_stripe(sh2);
goto unlock;
}
if (sh2)
release_stripe(sh2);
/* Need to write out all blocks after computing P&Q */
sh->disks = conf->raid_disks;
stripe_set_idx(sh->sector, conf, 0, sh);
compute_parity6(sh, RECONSTRUCT_WRITE);
for (i = conf->raid_disks ; i-- ; ) {
set_bit(R5_LOCKED, &sh->dev[i].flags);
s.locked++;
set_bit(R5_Wantwrite, &sh->dev[i].flags);
}
clear_bit(STRIPE_EXPANDING, &sh->state);
} else if (s.expanded) {
clear_bit(STRIPE_EXPAND_READY, &sh->state);
atomic_dec(&conf->reshape_stripes);
wake_up(&conf->wait_for_overlap);
md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
}
if (s.expanding && s.locked == 0 &&
!test_bit(STRIPE_COMPUTE_RUN, &sh->state))
handle_stripe_expansion(conf, sh, &r6s);
unlock:
spin_unlock(&sh->lock);
/* wait for this device to become unblocked */
if (unlikely(blocked_rdev))
md_wait_for_blocked_rdev(blocked_rdev, conf->mddev);
ops_run_io(sh, &s);
return_io(return_bi);
return blocked_rdev == NULL;
}
/* returns true if the stripe was handled */
static bool handle_stripe(struct stripe_head *sh, struct page *tmp_page)
{
if (sh->raid_conf->level == 6)
return handle_stripe6(sh, tmp_page);
else
return handle_stripe5(sh);
}
static void raid5_activate_delayed(raid5_conf_t *conf)
{
if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) {
while (!list_empty(&conf->delayed_list)) {
struct list_head *l = conf->delayed_list.next;
struct stripe_head *sh;
sh = list_entry(l, struct stripe_head, lru);
list_del_init(l);
clear_bit(STRIPE_DELAYED, &sh->state);
if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
atomic_inc(&conf->preread_active_stripes);
list_add_tail(&sh->lru, &conf->hold_list);
}
} else
blk_plug_device(conf->mddev->queue);
}
static void activate_bit_delay(raid5_conf_t *conf)
{
/* device_lock is held */
struct list_head head;
list_add(&head, &conf->bitmap_list);
list_del_init(&conf->bitmap_list);
while (!list_empty(&head)) {
struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru);
list_del_init(&sh->lru);
atomic_inc(&sh->count);
__release_stripe(conf, sh);
}
}
static void unplug_slaves(mddev_t *mddev)
{
raid5_conf_t *conf = mddev->private;
int i;
rcu_read_lock();
for (i = 0; i < conf->raid_disks; i++) {
mdk_rdev_t *rdev = rcu_dereference(conf->disks[i].rdev);
if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) {
struct request_queue *r_queue = bdev_get_queue(rdev->bdev);
atomic_inc(&rdev->nr_pending);
rcu_read_unlock();
blk_unplug(r_queue);
rdev_dec_pending(rdev, mddev);
rcu_read_lock();
}
}
rcu_read_unlock();
}
static void raid5_unplug_device(struct request_queue *q)
{
mddev_t *mddev = q->queuedata;
raid5_conf_t *conf = mddev->private;
unsigned long flags;
spin_lock_irqsave(&conf->device_lock, flags);
if (blk_remove_plug(q)) {
conf->seq_flush++;
raid5_activate_delayed(conf);
}
md_wakeup_thread(mddev->thread);
spin_unlock_irqrestore(&conf->device_lock, flags);
unplug_slaves(mddev);
}
static int raid5_congested(void *data, int bits)
{
mddev_t *mddev = data;
raid5_conf_t *conf = mddev->private;
/* No difference between reads and writes. Just check
* how busy the stripe_cache is
*/
if (conf->inactive_blocked)
return 1;
if (conf->quiesce)
return 1;
if (list_empty_careful(&conf->inactive_list))
return 1;
return 0;
}
/* We want read requests to align with chunks where possible,
* but write requests don't need to.
*/
static int raid5_mergeable_bvec(struct request_queue *q,
struct bvec_merge_data *bvm,
struct bio_vec *biovec)
{
mddev_t *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;
if ((bvm->bi_rw & 1) == WRITE)
return biovec->bv_len; /* always allow writes to be mergeable */
if (mddev->new_chunk_sectors < mddev->chunk_sectors)
chunk_sectors = mddev->new_chunk_sectors;
max = (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9;
if (max < 0) max = 0;
if (max <= biovec->bv_len && bio_sectors == 0)
return biovec->bv_len;
else
return max;
}
static int in_chunk_boundary(mddev_t *mddev, struct bio *bio)
{
sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev);
unsigned int chunk_sectors = mddev->chunk_sectors;
unsigned int bio_sectors = bio->bi_size >> 9;
if (mddev->new_chunk_sectors < mddev->chunk_sectors)
chunk_sectors = mddev->new_chunk_sectors;
return chunk_sectors >=
((sector & (chunk_sectors - 1)) + bio_sectors);
}
/*
* add bio to the retry LIFO ( in O(1) ... we are in interrupt )
* later sampled by raid5d.
*/
static void add_bio_to_retry(struct bio *bi,raid5_conf_t *conf)
{
unsigned long flags;
spin_lock_irqsave(&conf->device_lock, flags);
bi->bi_next = conf->retry_read_aligned_list;
conf->retry_read_aligned_list = bi;
spin_unlock_irqrestore(&conf->device_lock, flags);
md_wakeup_thread(conf->mddev->thread);
}
static struct bio *remove_bio_from_retry(raid5_conf_t *conf)
{
struct bio *bi;
bi = conf->retry_read_aligned;
if (bi) {
conf->retry_read_aligned = NULL;
return bi;
}
bi = conf->retry_read_aligned_list;
if(bi) {
conf->retry_read_aligned_list = bi->bi_next;
bi->bi_next = NULL;
/*
* this sets the active strip count to 1 and the processed
* strip count to zero (upper 8 bits)
*/
bi->bi_phys_segments = 1; /* biased count of active stripes */
}
return bi;
}
/*
* The "raid5_align_endio" should check if the read succeeded and if it
* did, call bio_endio on the original bio (having bio_put the new bio
* first).
* If the read failed..
*/
static void raid5_align_endio(struct bio *bi, int error)
{
struct bio* raid_bi = bi->bi_private;
mddev_t *mddev;
raid5_conf_t *conf;
int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
mdk_rdev_t *rdev;
bio_put(bi);
mddev = raid_bi->bi_bdev->bd_disk->queue->queuedata;
conf = mddev->private;
rdev = (void*)raid_bi->bi_next;
raid_bi->bi_next = NULL;
rdev_dec_pending(rdev, conf->mddev);
if (!error && uptodate) {
bio_endio(raid_bi, 0);
if (atomic_dec_and_test(&conf->active_aligned_reads))
wake_up(&conf->wait_for_stripe);
return;
}
pr_debug("raid5_align_endio : io error...handing IO for a retry\n");
add_bio_to_retry(raid_bi, conf);
}
static int bio_fits_rdev(struct bio *bi)
{
struct request_queue *q = bdev_get_queue(bi->bi_bdev);
if ((bi->bi_size>>9) > queue_max_sectors(q))
return 0;
blk_recount_segments(q, bi);
if (bi->bi_phys_segments > queue_max_phys_segments(q))
return 0;
if (q->merge_bvec_fn)
/* it's too hard to apply the merge_bvec_fn at this stage,
* just just give up
*/
return 0;
return 1;
}
static int chunk_aligned_read(struct request_queue *q, struct bio * raid_bio)
{
mddev_t *mddev = q->queuedata;
raid5_conf_t *conf = mddev->private;
unsigned int dd_idx;
struct bio* align_bi;
mdk_rdev_t *rdev;
if (!in_chunk_boundary(mddev, raid_bio)) {
pr_debug("chunk_aligned_read : non aligned\n");
return 0;
}
/*
* use bio_clone to make a copy of the bio
*/
align_bi = bio_clone(raid_bio, GFP_NOIO);
if (!align_bi)
return 0;
/*
* set bi_end_io to a new function, and set bi_private to the
* original bio.
*/
align_bi->bi_end_io = raid5_align_endio;
align_bi->bi_private = raid_bio;
/*
* compute position
*/
align_bi->bi_sector = raid5_compute_sector(conf, raid_bio->bi_sector,
0,
&dd_idx, NULL);
rcu_read_lock();
rdev = rcu_dereference(conf->disks[dd_idx].rdev);
if (rdev && test_bit(In_sync, &rdev->flags)) {
atomic_inc(&rdev->nr_pending);
rcu_read_unlock();
raid_bio->bi_next = (void*)rdev;
align_bi->bi_bdev = rdev->bdev;
align_bi->bi_flags &= ~(1 << BIO_SEG_VALID);
align_bi->bi_sector += rdev->data_offset;
if (!bio_fits_rdev(align_bi)) {
/* too big in some way */
bio_put(align_bi);
rdev_dec_pending(rdev, mddev);
return 0;
}
spin_lock_irq(&conf->device_lock);
wait_event_lock_irq(conf->wait_for_stripe,
conf->quiesce == 0,
conf->device_lock, /* nothing */);
atomic_inc(&conf->active_aligned_reads);
spin_unlock_irq(&conf->device_lock);
generic_make_request(align_bi);
return 1;
} else {
rcu_read_unlock();
bio_put(align_bi);
return 0;
}
}
/* __get_priority_stripe - get the next stripe to process
*
* Full stripe writes are allowed to pass preread active stripes up until
* the bypass_threshold is exceeded. In general the bypass_count
* increments when the handle_list is handled before the hold_list; however, it
* will not be incremented when STRIPE_IO_STARTED is sampled set signifying a
* stripe with in flight i/o. The bypass_count will be reset when the
* head of the hold_list has changed, i.e. the head was promoted to the
* handle_list.
*/
static struct stripe_head *__get_priority_stripe(raid5_conf_t *conf)
{
struct stripe_head *sh;
pr_debug("%s: handle: %s hold: %s full_writes: %d bypass_count: %d\n",
__func__,
list_empty(&conf->handle_list) ? "empty" : "busy",
list_empty(&conf->hold_list) ? "empty" : "busy",
atomic_read(&conf->pending_full_writes), conf->bypass_count);
if (!list_empty(&conf->handle_list)) {
sh = list_entry(conf->handle_list.next, typeof(*sh), lru);
if (list_empty(&conf->hold_list))
conf->bypass_count = 0;
else if (!test_bit(STRIPE_IO_STARTED, &sh->state)) {
if (conf->hold_list.next == conf->last_hold)
conf->bypass_count++;
else {
conf->last_hold = conf->hold_list.next;
conf->bypass_count -= conf->bypass_threshold;
if (conf->bypass_count < 0)
conf->bypass_count = 0;
}
}
} else if (!list_empty(&conf->hold_list) &&
((conf->bypass_threshold &&
conf->bypass_count > conf->bypass_threshold) ||
atomic_read(&conf->pending_full_writes) == 0)) {
sh = list_entry(conf->hold_list.next,
typeof(*sh), lru);
conf->bypass_count -= conf->bypass_threshold;
if (conf->bypass_count < 0)
conf->bypass_count = 0;
} else
return NULL;
list_del_init(&sh->lru);
atomic_inc(&sh->count);
BUG_ON(atomic_read(&sh->count) != 1);
return sh;
}
static int make_request(struct request_queue *q, struct bio * bi)
{
mddev_t *mddev = q->queuedata;
raid5_conf_t *conf = mddev->private;
int dd_idx;
sector_t new_sector;
sector_t logical_sector, last_sector;
struct stripe_head *sh;
const int rw = bio_data_dir(bi);
int cpu, remaining;
if (unlikely(bio_barrier(bi))) {
bio_endio(bi, -EOPNOTSUPP);
return 0;
}
md_write_start(mddev, bi);
cpu = part_stat_lock();
part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]);
part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw],
bio_sectors(bi));
part_stat_unlock();
if (rw == READ &&
mddev->reshape_position == MaxSector &&
chunk_aligned_read(q,bi))
return 0;
logical_sector = bi->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
last_sector = bi->bi_sector + (bi->bi_size>>9);
bi->bi_next = NULL;
bi->bi_phys_segments = 1; /* over-loaded to count active stripes */
for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
DEFINE_WAIT(w);
int disks, data_disks;
int previous;
retry:
previous = 0;
disks = conf->raid_disks;
prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
if (unlikely(conf->reshape_progress != MaxSector)) {
/* spinlock is needed as reshape_progress may be
* 64bit on a 32bit platform, and so it might be
* possible to see a half-updated value
* Ofcourse reshape_progress could change after
* the lock is dropped, so once we get a reference
* to the stripe that we think it is, we will have
* to check again.
*/
spin_lock_irq(&conf->device_lock);
if (mddev->delta_disks < 0
? logical_sector < conf->reshape_progress
: logical_sector >= conf->reshape_progress) {
disks = conf->previous_raid_disks;
previous = 1;
} else {
if (mddev->delta_disks < 0
? logical_sector < conf->reshape_safe
: logical_sector >= conf->reshape_safe) {
spin_unlock_irq(&conf->device_lock);
schedule();
goto retry;
}
}
spin_unlock_irq(&conf->device_lock);
}
data_disks = disks - conf->max_degraded;
new_sector = raid5_compute_sector(conf, logical_sector,
previous,
&dd_idx, NULL);
pr_debug("raid5: make_request, sector %llu logical %llu\n",
(unsigned long long)new_sector,
(unsigned long long)logical_sector);
sh = get_active_stripe(conf, new_sector, previous,
(bi->bi_rw&RWA_MASK), 0);
if (sh) {
if (unlikely(previous)) {
/* expansion might have moved on while waiting for a
* stripe, so we must do the range check again.
* Expansion could still move past after this
* test, but as we are holding a reference to
* 'sh', we know that if that happens,
* STRIPE_EXPANDING will get set and the expansion
* won't proceed until we finish with the stripe.
*/
int must_retry = 0;
spin_lock_irq(&conf->device_lock);
if (mddev->delta_disks < 0
? logical_sector >= conf->reshape_progress
: logical_sector < conf->reshape_progress)
/* mismatch, need to try again */
must_retry = 1;
spin_unlock_irq(&conf->device_lock);
if (must_retry) {
release_stripe(sh);
schedule();
goto retry;
}
}
if (bio_data_dir(bi) == WRITE &&
logical_sector >= mddev->suspend_lo &&
logical_sector < mddev->suspend_hi) {
release_stripe(sh);
/* As the suspend_* range is controlled by
* userspace, we want an interruptible
* wait.
*/
flush_signals(current);
prepare_to_wait(&conf->wait_for_overlap,
&w, TASK_INTERRUPTIBLE);
if (logical_sector >= mddev->suspend_lo &&
logical_sector < mddev->suspend_hi)
schedule();
goto retry;
}
if (test_bit(STRIPE_EXPANDING, &sh->state) ||
!add_stripe_bio(sh, bi, dd_idx, (bi->bi_rw&RW_MASK))) {
/* Stripe is busy expanding or
* add failed due to overlap. Flush everything
* and wait a while
*/
raid5_unplug_device(mddev->queue);
release_stripe(sh);
schedule();
goto retry;
}
finish_wait(&conf->wait_for_overlap, &w);
set_bit(STRIPE_HANDLE, &sh->state);
clear_bit(STRIPE_DELAYED, &sh->state);
release_stripe(sh);
} else {
/* cannot get stripe for read-ahead, just give-up */
clear_bit(BIO_UPTODATE, &bi->bi_flags);
finish_wait(&conf->wait_for_overlap, &w);
break;
}
}
spin_lock_irq(&conf->device_lock);
remaining = raid5_dec_bi_phys_segments(bi);
spin_unlock_irq(&conf->device_lock);
if (remaining == 0) {
if ( rw == WRITE )
md_write_end(mddev);
bio_endio(bi, 0);
}
return 0;
}
static sector_t raid5_size(mddev_t *mddev, sector_t sectors, int raid_disks);
static sector_t reshape_request(mddev_t *mddev, sector_t sector_nr, int *skipped)
{
/* reshaping is quite different to recovery/resync so it is
* handled quite separately ... here.
*
* On each call to sync_request, we gather one chunk worth of
* destination stripes and flag them as expanding.
* Then we find all the source stripes and request reads.
* As the reads complete, handle_stripe will copy the data
* into the destination stripe and release that stripe.
*/
raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
struct stripe_head *sh;
sector_t first_sector, last_sector;
int raid_disks = conf->previous_raid_disks;
int data_disks = raid_disks - conf->max_degraded;
int new_data_disks = conf->raid_disks - conf->max_degraded;
int i;
int dd_idx;
sector_t writepos, readpos, safepos;
sector_t stripe_addr;
int reshape_sectors;
struct list_head stripes;
if (sector_nr == 0) {
/* If restarting in the middle, skip the initial sectors */
if (mddev->delta_disks < 0 &&
conf->reshape_progress < raid5_size(mddev, 0, 0)) {
sector_nr = raid5_size(mddev, 0, 0)
- conf->reshape_progress;
} else if (mddev->delta_disks > 0 &&
conf->reshape_progress > 0)
sector_nr = conf->reshape_progress;
sector_div(sector_nr, new_data_disks);
if (sector_nr) {
*skipped = 1;
return sector_nr;
}
}
/* We need to process a full chunk at a time.
* If old and new chunk sizes differ, we need to process the
* largest of these
*/
if (mddev->new_chunk_sectors > mddev->chunk_sectors)
reshape_sectors = mddev->new_chunk_sectors;
else
reshape_sectors = mddev->chunk_sectors;
/* we update the metadata when there is more than 3Meg
* in the block range (that is rather arbitrary, should
* probably be time based) or when the data about to be
* copied would over-write the source of the data at
* the front of the range.
* i.e. one new_stripe along from reshape_progress new_maps
* to after where reshape_safe old_maps to
*/
writepos = conf->reshape_progress;
sector_div(writepos, new_data_disks);
readpos = conf->reshape_progress;
sector_div(readpos, data_disks);
safepos = conf->reshape_safe;
sector_div(safepos, data_disks);
if (mddev->delta_disks < 0) {
writepos -= min_t(sector_t, reshape_sectors, writepos);
readpos += reshape_sectors;
safepos += reshape_sectors;
} else {
writepos += reshape_sectors;
readpos -= min_t(sector_t, reshape_sectors, readpos);
safepos -= min_t(sector_t, reshape_sectors, safepos);
}
/* 'writepos' is the most advanced device address we might write.
* 'readpos' is the least advanced device address we might read.
* 'safepos' is the least address recorded in the metadata as having
* been reshaped.
* If 'readpos' is behind 'writepos', then there is no way that we can
* ensure safety in the face of a crash - that must be done by userspace
* making a backup of the data. So in that case there is no particular
* rush to update metadata.
* Otherwise if 'safepos' is behind 'writepos', then we really need to
* update the metadata to advance 'safepos' to match 'readpos' so that
* we can be safe in the event of a crash.
* So we insist on updating metadata if safepos is behind writepos and
* readpos is beyond writepos.
* In any case, update the metadata every 10 seconds.
* Maybe that number should be configurable, but I'm not sure it is
* worth it.... maybe it could be a multiple of safemode_delay???
*/
if ((mddev->delta_disks < 0
? (safepos > writepos && readpos < writepos)
: (safepos < writepos && readpos > writepos)) ||
time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
/* Cannot proceed until we've updated the superblock... */
wait_event(conf->wait_for_overlap,
atomic_read(&conf->reshape_stripes)==0);
mddev->reshape_position = conf->reshape_progress;
mddev->curr_resync_completed = mddev->curr_resync;
conf->reshape_checkpoint = jiffies;
set_bit(MD_CHANGE_DEVS, &mddev->flags);
md_wakeup_thread(mddev->thread);
wait_event(mddev->sb_wait, mddev->flags == 0 ||
kthread_should_stop());
spin_lock_irq(&conf->device_lock);
conf->reshape_safe = mddev->reshape_position;
spin_unlock_irq(&conf->device_lock);
wake_up(&conf->wait_for_overlap);
sysfs_notify(&mddev->kobj, NULL, "sync_completed");
}
if (mddev->delta_disks < 0) {
BUG_ON(conf->reshape_progress == 0);
stripe_addr = writepos;
BUG_ON((mddev->dev_sectors &
~((sector_t)reshape_sectors - 1))
- reshape_sectors - stripe_addr
!= sector_nr);
} else {
BUG_ON(writepos != sector_nr + reshape_sectors);
stripe_addr = sector_nr;
}
INIT_LIST_HEAD(&stripes);
for (i = 0; i < reshape_sectors; i += STRIPE_SECTORS) {
int j;
int skipped = 0;
sh = get_active_stripe(conf, stripe_addr+i, 0, 0, 1);
set_bit(STRIPE_EXPANDING, &sh->state);
atomic_inc(&conf->reshape_stripes);
/* If any of this stripe is beyond the end of the old
* array, then we need to zero those blocks
*/
for (j=sh->disks; j--;) {
sector_t s;
if (j == sh->pd_idx)
continue;
if (conf->level == 6 &&
j == sh->qd_idx)
continue;
s = compute_blocknr(sh, j, 0);
if (s < raid5_size(mddev, 0, 0)) {
skipped = 1;
continue;
}
memset(page_address(sh->dev[j].page), 0, STRIPE_SIZE);
set_bit(R5_Expanded, &sh->dev[j].flags);
set_bit(R5_UPTODATE, &sh->dev[j].flags);
}
if (!skipped) {
set_bit(STRIPE_EXPAND_READY, &sh->state);
set_bit(STRIPE_HANDLE, &sh->state);
}
list_add(&sh->lru, &stripes);
}
spin_lock_irq(&conf->device_lock);
if (mddev->delta_disks < 0)
conf->reshape_progress -= reshape_sectors * new_data_disks;
else
conf->reshape_progress += reshape_sectors * new_data_disks;
spin_unlock_irq(&conf->device_lock);
/* Ok, those stripe are ready. We can start scheduling
* reads on the source stripes.
* The source stripes are determined by mapping the first and last
* block on the destination stripes.
*/
first_sector =
raid5_compute_sector(conf, stripe_addr*(new_data_disks),
1, &dd_idx, NULL);
last_sector =
raid5_compute_sector(conf, ((stripe_addr+reshape_sectors)
* new_data_disks - 1),
1, &dd_idx, NULL);
if (last_sector >= mddev->dev_sectors)
last_sector = mddev->dev_sectors - 1;
while (first_sector <= last_sector) {
sh = get_active_stripe(conf, first_sector, 1, 0, 1);
set_bit(STRIPE_EXPAND_SOURCE, &sh->state);
set_bit(STRIPE_HANDLE, &sh->state);
release_stripe(sh);
first_sector += STRIPE_SECTORS;
}
/* Now that the sources are clearly marked, we can release
* the destination stripes
*/
while (!list_empty(&stripes)) {
sh = list_entry(stripes.next, struct stripe_head, lru);
list_del_init(&sh->lru);
release_stripe(sh);
}
/* If this takes us to the resync_max point where we have to pause,
* then we need to write out the superblock.
*/
sector_nr += reshape_sectors;
if ((sector_nr - mddev->curr_resync_completed) * 2
>= mddev->resync_max - mddev->curr_resync_completed) {
/* Cannot proceed until we've updated the superblock... */
wait_event(conf->wait_for_overlap,
atomic_read(&conf->reshape_stripes) == 0);
mddev->reshape_position = conf->reshape_progress;
mddev->curr_resync_completed = mddev->curr_resync + reshape_sectors;
conf->reshape_checkpoint = jiffies;
set_bit(MD_CHANGE_DEVS, &mddev->flags);
md_wakeup_thread(mddev->thread);
wait_event(mddev->sb_wait,
!test_bit(MD_CHANGE_DEVS, &mddev->flags)
|| kthread_should_stop());
spin_lock_irq(&conf->device_lock);
conf->reshape_safe = mddev->reshape_position;
spin_unlock_irq(&conf->device_lock);
wake_up(&conf->wait_for_overlap);
sysfs_notify(&mddev->kobj, NULL, "sync_completed");
}
return reshape_sectors;
}
/* FIXME go_faster isn't used */
static inline sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
{
raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
struct stripe_head *sh;
sector_t max_sector = mddev->dev_sectors;
int sync_blocks;
int still_degraded = 0;
int i;
if (sector_nr >= max_sector) {
/* just being told to finish up .. nothing much to do */
unplug_slaves(mddev);
if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
end_reshape(conf);
return 0;
}
if (mddev->curr_resync < max_sector) /* aborted */
bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
&sync_blocks, 1);
else /* completed sync */
conf->fullsync = 0;
bitmap_close_sync(mddev->bitmap);
return 0;
}
if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
return reshape_request(mddev, sector_nr, skipped);
/* No need to check resync_max as we never do more than one
* stripe, and as resync_max will always be on a chunk boundary,
* if the check in md_do_sync didn't fire, there is no chance
* of overstepping resync_max here
*/
/* if there is too many failed drives and we are trying
* to resync, then assert that we are finished, because there is
* nothing we can do.
*/
if (mddev->degraded >= conf->max_degraded &&
test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
sector_t rv = mddev->dev_sectors - sector_nr;
*skipped = 1;
return rv;
}
if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
!conf->fullsync && sync_blocks >= STRIPE_SECTORS) {
/* we can skip this block, and probably more */
sync_blocks /= STRIPE_SECTORS;
*skipped = 1;
return sync_blocks * STRIPE_SECTORS; /* keep things rounded to whole stripes */
}
bitmap_cond_end_sync(mddev->bitmap, sector_nr);
sh = get_active_stripe(conf, sector_nr, 0, 1, 0);
if (sh == NULL) {
sh = get_active_stripe(conf, sector_nr, 0, 0, 0);
/* make sure we don't swamp the stripe cache if someone else
* is trying to get access
*/
schedule_timeout_uninterruptible(1);
}
/* Need to check if array will still be degraded after recovery/resync
* We don't need to check the 'failed' flag as when that gets set,
* recovery aborts.
*/
for (i = 0; i < conf->raid_disks; i++)
if (conf->disks[i].rdev == NULL)
still_degraded = 1;
bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, still_degraded);
spin_lock(&sh->lock);
set_bit(STRIPE_SYNCING, &sh->state);
clear_bit(STRIPE_INSYNC, &sh->state);
spin_unlock(&sh->lock);
/* wait for any blocked device to be handled */
while(unlikely(!handle_stripe(sh, NULL)))
;
release_stripe(sh);
return STRIPE_SECTORS;
}
static int retry_aligned_read(raid5_conf_t *conf, struct bio *raid_bio)
{
/* We may not be able to submit a whole bio at once as there
* may not be enough stripe_heads available.
* We cannot pre-allocate enough stripe_heads as we may need
* more than exist in the cache (if we allow ever large chunks).
* So we do one stripe head at a time and record in
* ->bi_hw_segments how many have been done.
*
* We *know* that this entire raid_bio is in one chunk, so
* it will be only one 'dd_idx' and only need one call to raid5_compute_sector.
*/
struct stripe_head *sh;
int dd_idx;
sector_t sector, logical_sector, last_sector;
int scnt = 0;
int remaining;
int handled = 0;
logical_sector = raid_bio->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
sector = raid5_compute_sector(conf, logical_sector,
0, &dd_idx, NULL);
last_sector = raid_bio->bi_sector + (raid_bio->bi_size>>9);
for (; logical_sector < last_sector;
logical_sector += STRIPE_SECTORS,
sector += STRIPE_SECTORS,
scnt++) {
if (scnt < raid5_bi_hw_segments(raid_bio))
/* already done this stripe */
continue;
sh = get_active_stripe(conf, sector, 0, 1, 0);
if (!sh) {
/* failed to get a stripe - must wait */
raid5_set_bi_hw_segments(raid_bio, scnt);
conf->retry_read_aligned = raid_bio;
return handled;
}
set_bit(R5_ReadError, &sh->dev[dd_idx].flags);
if (!add_stripe_bio(sh, raid_bio, dd_idx, 0)) {
release_stripe(sh);
raid5_set_bi_hw_segments(raid_bio, scnt);
conf->retry_read_aligned = raid_bio;
return handled;
}
handle_stripe(sh, NULL);
release_stripe(sh);
handled++;
}
spin_lock_irq(&conf->device_lock);
remaining = raid5_dec_bi_phys_segments(raid_bio);
spin_unlock_irq(&conf->device_lock);
if (remaining == 0)
bio_endio(raid_bio, 0);
if (atomic_dec_and_test(&conf->active_aligned_reads))
wake_up(&conf->wait_for_stripe);
return handled;
}
/*
* This is our raid5 kernel thread.
*
* We scan the hash table for stripes which can be handled now.
* During the scan, completed stripes are saved for us by the interrupt
* handler, so that they will not have to wait for our next wakeup.
*/
static void raid5d(mddev_t *mddev)
{
struct stripe_head *sh;
raid5_conf_t *conf = mddev->private;
int handled;
pr_debug("+++ raid5d active\n");
md_check_recovery(mddev);
handled = 0;
spin_lock_irq(&conf->device_lock);
while (1) {
struct bio *bio;
if (conf->seq_flush != conf->seq_write) {
int seq = conf->seq_flush;
spin_unlock_irq(&conf->device_lock);
bitmap_unplug(mddev->bitmap);
spin_lock_irq(&conf->device_lock);
conf->seq_write = seq;
activate_bit_delay(conf);
}
while ((bio = remove_bio_from_retry(conf))) {
int ok;
spin_unlock_irq(&conf->device_lock);
ok = retry_aligned_read(conf, bio);
spin_lock_irq(&conf->device_lock);
if (!ok)
break;
handled++;
}
sh = __get_priority_stripe(conf);
if (!sh)
break;
spin_unlock_irq(&conf->device_lock);
handled++;
handle_stripe(sh, conf->spare_page);
release_stripe(sh);
spin_lock_irq(&conf->device_lock);
}
pr_debug("%d stripes handled\n", handled);
spin_unlock_irq(&conf->device_lock);
async_tx_issue_pending_all();
unplug_slaves(mddev);
pr_debug("--- raid5d inactive\n");
}
static ssize_t
raid5_show_stripe_cache_size(mddev_t *mddev, char *page)
{
raid5_conf_t *conf = mddev->private;
if (conf)
return sprintf(page, "%d\n", conf->max_nr_stripes);
else
return 0;
}
static ssize_t
raid5_store_stripe_cache_size(mddev_t *mddev, const char *page, size_t len)
{
raid5_conf_t *conf = mddev->private;
unsigned long new;
int err;
if (len >= PAGE_SIZE)
return -EINVAL;
if (!conf)
return -ENODEV;
if (strict_strtoul(page, 10, &new))
return -EINVAL;
if (new <= 16 || new > 32768)
return -EINVAL;
while (new < conf->max_nr_stripes) {
if (drop_one_stripe(conf))
conf->max_nr_stripes--;
else
break;
}
err = md_allow_write(mddev);
if (err)
return err;
while (new > conf->max_nr_stripes) {
if (grow_one_stripe(conf))
conf->max_nr_stripes++;
else break;
}
return len;
}
static struct md_sysfs_entry
raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR,
raid5_show_stripe_cache_size,
raid5_store_stripe_cache_size);
static ssize_t
raid5_show_preread_threshold(mddev_t *mddev, char *page)
{
raid5_conf_t *conf = mddev->private;
if (conf)
return sprintf(page, "%d\n", conf->bypass_threshold);
else
return 0;
}
static ssize_t
raid5_store_preread_threshold(mddev_t *mddev, const char *page, size_t len)
{
raid5_conf_t *conf = mddev->private;
unsigned long new;
if (len >= PAGE_SIZE)
return -EINVAL;
if (!conf)
return -ENODEV;
if (strict_strtoul(page, 10, &new))
return -EINVAL;
if (new > conf->max_nr_stripes)
return -EINVAL;
conf->bypass_threshold = new;
return len;
}
static struct md_sysfs_entry
raid5_preread_bypass_threshold = __ATTR(preread_bypass_threshold,
S_IRUGO | S_IWUSR,
raid5_show_preread_threshold,
raid5_store_preread_threshold);
static ssize_t
stripe_cache_active_show(mddev_t *mddev, char *page)
{
raid5_conf_t *conf = mddev->private;
if (conf)
return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
else
return 0;
}
static struct md_sysfs_entry
raid5_stripecache_active = __ATTR_RO(stripe_cache_active);
static struct attribute *raid5_attrs[] = {
&raid5_stripecache_size.attr,
&raid5_stripecache_active.attr,
&raid5_preread_bypass_threshold.attr,
NULL,
};
static struct attribute_group raid5_attrs_group = {
.name = NULL,
.attrs = raid5_attrs,
};
static sector_t
raid5_size(mddev_t *mddev, sector_t sectors, int raid_disks)
{
raid5_conf_t *conf = mddev->private;
if (!sectors)
sectors = mddev->dev_sectors;
if (!raid_disks) {
/* size is defined by the smallest of previous and new size */
if (conf->raid_disks < conf->previous_raid_disks)
raid_disks = conf->raid_disks;
else
raid_disks = conf->previous_raid_disks;
}
sectors &= ~((sector_t)mddev->chunk_sectors - 1);
sectors &= ~((sector_t)mddev->new_chunk_sectors - 1);
return sectors * (raid_disks - conf->max_degraded);
}
static raid5_conf_t *setup_conf(mddev_t *mddev)
{
raid5_conf_t *conf;
int raid_disk, memory;
mdk_rdev_t *rdev;
struct disk_info *disk;
if (mddev->new_level != 5
&& mddev->new_level != 4
&& mddev->new_level != 6) {
printk(KERN_ERR "raid5: %s: raid level not set to 4/5/6 (%d)\n",
mdname(mddev), mddev->new_level);
return ERR_PTR(-EIO);
}
if ((mddev->new_level == 5
&& !algorithm_valid_raid5(mddev->new_layout)) ||
(mddev->new_level == 6
&& !algorithm_valid_raid6(mddev->new_layout))) {
printk(KERN_ERR "raid5: %s: layout %d not supported\n",
mdname(mddev), mddev->new_layout);
return ERR_PTR(-EIO);
}
if (mddev->new_level == 6 && mddev->raid_disks < 4) {
printk(KERN_ERR "raid6: not enough configured devices for %s (%d, minimum 4)\n",
mdname(mddev), mddev->raid_disks);
return ERR_PTR(-EINVAL);
}
if (!mddev->new_chunk_sectors ||
(mddev->new_chunk_sectors << 9) % PAGE_SIZE ||
!is_power_of_2(mddev->new_chunk_sectors)) {
printk(KERN_ERR "raid5: invalid chunk size %d for %s\n",
mddev->new_chunk_sectors << 9, mdname(mddev));
return ERR_PTR(-EINVAL);
}
conf = kzalloc(sizeof(raid5_conf_t), GFP_KERNEL);
if (conf == NULL)
goto abort;
conf->raid_disks = mddev->raid_disks;
if (mddev->reshape_position == MaxSector)
conf->previous_raid_disks = mddev->raid_disks;
else
conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks;
conf->disks = kzalloc(conf->raid_disks * sizeof(struct disk_info),
GFP_KERNEL);
if (!conf->disks)
goto abort;
conf->mddev = mddev;
if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL)
goto abort;
if (mddev->new_level == 6) {
conf->spare_page = alloc_page(GFP_KERNEL);
if (!conf->spare_page)
goto abort;
}
spin_lock_init(&conf->device_lock);
init_waitqueue_head(&conf->wait_for_stripe);
init_waitqueue_head(&conf->wait_for_overlap);
INIT_LIST_HEAD(&conf->handle_list);
INIT_LIST_HEAD(&conf->hold_list);
INIT_LIST_HEAD(&conf->delayed_list);
INIT_LIST_HEAD(&conf->bitmap_list);
INIT_LIST_HEAD(&conf->inactive_list);
atomic_set(&conf->active_stripes, 0);
atomic_set(&conf->preread_active_stripes, 0);
atomic_set(&conf->active_aligned_reads, 0);
conf->bypass_threshold = BYPASS_THRESHOLD;
pr_debug("raid5: run(%s) called.\n", mdname(mddev));
list_for_each_entry(rdev, &mddev->disks, same_set) {
raid_disk = rdev->raid_disk;
if (raid_disk >= conf->raid_disks
|| raid_disk < 0)
continue;
disk = conf->disks + raid_disk;
disk->rdev = rdev;
if (test_bit(In_sync, &rdev->flags)) {
char b[BDEVNAME_SIZE];
printk(KERN_INFO "raid5: device %s operational as raid"
" disk %d\n", bdevname(rdev->bdev,b),
raid_disk);
} else
/* Cannot rely on bitmap to complete recovery */
conf->fullsync = 1;
}
conf->chunk_sectors = mddev->new_chunk_sectors;
conf->level = mddev->new_level;
if (conf->level == 6)
conf->max_degraded = 2;
else
conf->max_degraded = 1;
conf->algorithm = mddev->new_layout;
conf->max_nr_stripes = NR_STRIPES;
conf->reshape_progress = mddev->reshape_position;
if (conf->reshape_progress != MaxSector) {
conf->prev_chunk_sectors = mddev->chunk_sectors;
conf->prev_algo = mddev->layout;
}
memory = conf->max_nr_stripes * (sizeof(struct stripe_head) +
conf->raid_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
if (grow_stripes(conf, conf->max_nr_stripes)) {
printk(KERN_ERR
"raid5: couldn't allocate %dkB for buffers\n", memory);
goto abort;
} else
printk(KERN_INFO "raid5: allocated %dkB for %s\n",
memory, mdname(mddev));
conf->thread = md_register_thread(raid5d, mddev, "%s_raid5");
if (!conf->thread) {
printk(KERN_ERR
"raid5: couldn't allocate thread for %s\n",
mdname(mddev));
goto abort;
}
return conf;
abort:
if (conf) {
shrink_stripes(conf);
safe_put_page(conf->spare_page);
kfree(conf->disks);
kfree(conf->stripe_hashtbl);
kfree(conf);
return ERR_PTR(-EIO);
} else
return ERR_PTR(-ENOMEM);
}
static int run(mddev_t *mddev)
{
raid5_conf_t *conf;
int working_disks = 0, chunk_size;
mdk_rdev_t *rdev;
if (mddev->recovery_cp != MaxSector)
printk(KERN_NOTICE "raid5: %s is not clean"
" -- starting background reconstruction\n",
mdname(mddev));
if (mddev->reshape_position != MaxSector) {
/* Check that we can continue the reshape.
* Currently only disks can change, it must
* increase, and we must be past the point where
* a stripe over-writes itself
*/
sector_t here_new, here_old;
int old_disks;
int max_degraded = (mddev->level == 6 ? 2 : 1);
if (mddev->new_level != mddev->level) {
printk(KERN_ERR "raid5: %s: unsupported reshape "
"required - aborting.\n",
mdname(mddev));
return -EINVAL;
}
old_disks = mddev->raid_disks - mddev->delta_disks;
/* reshape_position must be on a new-stripe boundary, and one
* further up in new geometry must map after here in old
* geometry.
*/
here_new = mddev->reshape_position;
if (sector_div(here_new, mddev->new_chunk_sectors *
(mddev->raid_disks - max_degraded))) {
printk(KERN_ERR "raid5: reshape_position not "
"on a stripe boundary\n");
return -EINVAL;
}
/* here_new is the stripe we will write to */
here_old = mddev->reshape_position;
sector_div(here_old, mddev->chunk_sectors *
(old_disks-max_degraded));
/* here_old is the first stripe that we might need to read
* from */
if (here_new >= here_old) {
/* Reading from the same stripe as writing to - bad */
printk(KERN_ERR "raid5: reshape_position too early for "
"auto-recovery - aborting.\n");
return -EINVAL;
}
printk(KERN_INFO "raid5: reshape will continue\n");
/* OK, we should be able to continue; */
} else {
BUG_ON(mddev->level != mddev->new_level);
BUG_ON(mddev->layout != mddev->new_layout);
BUG_ON(mddev->chunk_sectors != mddev->new_chunk_sectors);
BUG_ON(mddev->delta_disks != 0);
}
if (mddev->private == NULL)
conf = setup_conf(mddev);
else
conf = mddev->private;
if (IS_ERR(conf))
return PTR_ERR(conf);
mddev->thread = conf->thread;
conf->thread = NULL;
mddev->private = conf;
/*
* 0 for a fully functional array, 1 or 2 for a degraded array.
*/
list_for_each_entry(rdev, &mddev->disks, same_set)
if (rdev->raid_disk >= 0 &&
test_bit(In_sync, &rdev->flags))
working_disks++;
mddev->degraded = conf->raid_disks - working_disks;
if (mddev->degraded > conf->max_degraded) {
printk(KERN_ERR "raid5: not enough operational devices for %s"
" (%d/%d failed)\n",
mdname(mddev), mddev->degraded, conf->raid_disks);
goto abort;
}
/* device size must be a multiple of chunk size */
mddev->dev_sectors &= ~(mddev->chunk_sectors - 1);
mddev->resync_max_sectors = mddev->dev_sectors;
if (mddev->degraded > 0 &&
mddev->recovery_cp != MaxSector) {
if (mddev->ok_start_degraded)
printk(KERN_WARNING
"raid5: starting dirty degraded array: %s"
"- data corruption possible.\n",
mdname(mddev));
else {
printk(KERN_ERR
"raid5: cannot start dirty degraded array for %s\n",
mdname(mddev));
goto abort;
}
}
if (mddev->degraded == 0)
printk("raid5: raid level %d set %s active with %d out of %d"
" devices, algorithm %d\n", conf->level, mdname(mddev),
mddev->raid_disks-mddev->degraded, mddev->raid_disks,
mddev->new_layout);
else
printk(KERN_ALERT "raid5: raid level %d set %s active with %d"
" out of %d devices, algorithm %d\n", conf->level,
mdname(mddev), mddev->raid_disks - mddev->degraded,
mddev->raid_disks, mddev->new_layout);
print_raid5_conf(conf);
if (conf->reshape_progress != MaxSector) {
printk("...ok start reshape thread\n");
conf->reshape_safe = conf->reshape_progress;
atomic_set(&conf->reshape_stripes, 0);
clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
mddev->sync_thread = md_register_thread(md_do_sync, mddev,
"%s_reshape");
}
/* read-ahead size must cover two whole stripes, which is
* 2 * (datadisks) * chunksize where 'n' is the number of raid devices
*/
{
int data_disks = conf->previous_raid_disks - conf->max_degraded;
int stripe = data_disks *
((mddev->chunk_sectors << 9) / PAGE_SIZE);
if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
}
/* Ok, everything is just fine now */
if (sysfs_create_group(&mddev->kobj, &raid5_attrs_group))
printk(KERN_WARNING
"raid5: failed to create sysfs attributes for %s\n",
mdname(mddev));
mddev->queue->queue_lock = &conf->device_lock;
mddev->queue->unplug_fn = raid5_unplug_device;
mddev->queue->backing_dev_info.congested_data = mddev;
mddev->queue->backing_dev_info.congested_fn = raid5_congested;
md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
blk_queue_merge_bvec(mddev->queue, raid5_mergeable_bvec);
chunk_size = mddev->chunk_sectors << 9;
blk_queue_io_min(mddev->queue, chunk_size);
blk_queue_io_opt(mddev->queue, chunk_size *
(conf->raid_disks - conf->max_degraded));
list_for_each_entry(rdev, &mddev->disks, same_set)
disk_stack_limits(mddev->gendisk, rdev->bdev,
rdev->data_offset << 9);
return 0;
abort:
md_unregister_thread(mddev->thread);
mddev->thread = NULL;
if (conf) {
shrink_stripes(conf);
print_raid5_conf(conf);
safe_put_page(conf->spare_page);
kfree(conf->disks);
kfree(conf->stripe_hashtbl);
kfree(conf);
}
mddev->private = NULL;
printk(KERN_ALERT "raid5: failed to run raid set %s\n", mdname(mddev));
return -EIO;
}
static int stop(mddev_t *mddev)
{
raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
md_unregister_thread(mddev->thread);
mddev->thread = NULL;
shrink_stripes(conf);
kfree(conf->stripe_hashtbl);
mddev->queue->backing_dev_info.congested_fn = NULL;
blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
sysfs_remove_group(&mddev->kobj, &raid5_attrs_group);
kfree(conf->disks);
kfree(conf);
mddev->private = NULL;
return 0;
}
#ifdef DEBUG
static void print_sh(struct seq_file *seq, struct stripe_head *sh)
{
int i;
seq_printf(seq, "sh %llu, pd_idx %d, state %ld.\n",
(unsigned long long)sh->sector, sh->pd_idx, sh->state);
seq_printf(seq, "sh %llu, count %d.\n",
(unsigned long long)sh->sector, atomic_read(&sh->count));
seq_printf(seq, "sh %llu, ", (unsigned long long)sh->sector);
for (i = 0; i < sh->disks; i++) {
seq_printf(seq, "(cache%d: %p %ld) ",
i, sh->dev[i].page, sh->dev[i].flags);
}
seq_printf(seq, "\n");
}
static void printall(struct seq_file *seq, raid5_conf_t *conf)
{
struct stripe_head *sh;
struct hlist_node *hn;
int i;
spin_lock_irq(&conf->device_lock);
for (i = 0; i < NR_HASH; i++) {
hlist_for_each_entry(sh, hn, &conf->stripe_hashtbl[i], hash) {
if (sh->raid_conf != conf)
continue;
print_sh(seq, sh);
}
}
spin_unlock_irq(&conf->device_lock);
}
#endif
static void status(struct seq_file *seq, mddev_t *mddev)
{
raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
int i;
seq_printf(seq, " level %d, %dk chunk, algorithm %d", mddev->level,
mddev->chunk_sectors / 2, mddev->layout);
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->disks[i].rdev &&
test_bit(In_sync, &conf->disks[i].rdev->flags) ? "U" : "_");
seq_printf (seq, "]");
#ifdef DEBUG
seq_printf (seq, "\n");
printall(seq, conf);
#endif
}
static void print_raid5_conf (raid5_conf_t *conf)
{
int i;
struct disk_info *tmp;
printk("RAID5 conf printout:\n");
if (!conf) {
printk("(conf==NULL)\n");
return;
}
printk(" --- rd:%d wd:%d\n", conf->raid_disks,
conf->raid_disks - conf->mddev->degraded);
for (i = 0; i < conf->raid_disks; i++) {
char b[BDEVNAME_SIZE];
tmp = conf->disks + i;
if (tmp->rdev)
printk(" disk %d, o:%d, dev:%s\n",
i, !test_bit(Faulty, &tmp->rdev->flags),
bdevname(tmp->rdev->bdev,b));
}
}
static int raid5_spare_active(mddev_t *mddev)
{
int i;
raid5_conf_t *conf = mddev->private;
struct disk_info *tmp;
for (i = 0; i < conf->raid_disks; i++) {
tmp = conf->disks + i;
if (tmp->rdev
&& !test_bit(Faulty, &tmp->rdev->flags)
&& !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
unsigned long flags;
spin_lock_irqsave(&conf->device_lock, flags);
mddev->degraded--;
spin_unlock_irqrestore(&conf->device_lock, flags);
}
}
print_raid5_conf(conf);
return 0;
}
static int raid5_remove_disk(mddev_t *mddev, int number)
{
raid5_conf_t *conf = mddev->private;
int err = 0;
mdk_rdev_t *rdev;
struct disk_info *p = conf->disks + number;
print_raid5_conf(conf);
rdev = p->rdev;
if (rdev) {
if (number >= conf->raid_disks &&
conf->reshape_progress == MaxSector)
clear_bit(In_sync, &rdev->flags);
if (test_bit(In_sync, &rdev->flags) ||
atomic_read(&rdev->nr_pending)) {
err = -EBUSY;
goto abort;
}
/* Only remove non-faulty devices if recovery
* isn't possible.
*/
if (!test_bit(Faulty, &rdev->flags) &&
mddev->degraded <= conf->max_degraded &&
number < conf->raid_disks) {
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;
}
}
abort:
print_raid5_conf(conf);
return err;
}
static int raid5_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
{
raid5_conf_t *conf = mddev->private;
int err = -EEXIST;
int disk;
struct disk_info *p;
int first = 0;
int last = conf->raid_disks - 1;
if (mddev->degraded > conf->max_degraded)
/* no point adding a device */
return -EINVAL;
if (rdev->raid_disk >= 0)
first = last = rdev->raid_disk;
/*
* find the disk ... but prefer rdev->saved_raid_disk
* if possible.
*/
if (rdev->saved_raid_disk >= 0 &&
rdev->saved_raid_disk >= first &&
conf->disks[rdev->saved_raid_disk].rdev == NULL)
disk = rdev->saved_raid_disk;
else
disk = first;
for ( ; disk <= last ; disk++)
if ((p=conf->disks + disk)->rdev == NULL) {
clear_bit(In_sync, &rdev->flags);
rdev->raid_disk = disk;
err = 0;
if (rdev->saved_raid_disk != disk)
conf->fullsync = 1;
rcu_assign_pointer(p->rdev, rdev);
break;
}
print_raid5_conf(conf);
return err;
}
static int raid5_resize(mddev_t *mddev, sector_t sectors)
{
/* no resync is happening, and there is enough space
* on all devices, so we can resize.
* We need to make sure resync covers any new space.
* If the array is shrinking we should possibly wait until
* any io in the removed space completes, but it hardly seems
* worth it.
*/
sectors &= ~((sector_t)mddev->chunk_sectors - 1);
md_set_array_sectors(mddev, raid5_size(mddev, sectors,
mddev->raid_disks));
if (mddev->array_sectors >
raid5_size(mddev, sectors, mddev->raid_disks))
return -EINVAL;
set_capacity(mddev->gendisk, mddev->array_sectors);
mddev->changed = 1;
if (sectors > mddev->dev_sectors && mddev->recovery_cp == MaxSector) {
mddev->recovery_cp = mddev->dev_sectors;
set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
}
mddev->dev_sectors = sectors;
mddev->resync_max_sectors = sectors;
return 0;
}
static int check_stripe_cache(mddev_t *mddev)
{
/* Can only proceed if there are plenty of stripe_heads.
* We need a minimum of one full stripe,, and for sensible progress
* it is best to have about 4 times that.
* If we require 4 times, then the default 256 4K stripe_heads will
* allow for chunk sizes up to 256K, which is probably OK.
* If the chunk size is greater, user-space should request more
* stripe_heads first.
*/
raid5_conf_t *conf = mddev->private;
if (((mddev->chunk_sectors << 9) / STRIPE_SIZE) * 4
> conf->max_nr_stripes ||
((mddev->new_chunk_sectors << 9) / STRIPE_SIZE) * 4
> conf->max_nr_stripes) {
printk(KERN_WARNING "raid5: reshape: not enough stripes. Needed %lu\n",
((max(mddev->chunk_sectors, mddev->new_chunk_sectors) << 9)
/ STRIPE_SIZE)*4);
return 0;
}
return 1;
}
static int check_reshape(mddev_t *mddev)
{
raid5_conf_t *conf = mddev->private;
if (mddev->delta_disks == 0 &&
mddev->new_layout == mddev->layout &&
mddev->new_chunk_sectors == mddev->chunk_sectors)
return 0; /* nothing to do */
if (mddev->bitmap)
/* Cannot grow a bitmap yet */
return -EBUSY;
if (mddev->degraded > conf->max_degraded)
return -EINVAL;
if (mddev->delta_disks < 0) {
/* We might be able to shrink, but the devices must
* be made bigger first.
* For raid6, 4 is the minimum size.
* Otherwise 2 is the minimum
*/
int min = 2;
if (mddev->level == 6)
min = 4;
if (mddev->raid_disks + mddev->delta_disks < min)
return -EINVAL;
}
if (!check_stripe_cache(mddev))
return -ENOSPC;
return resize_stripes(conf, conf->raid_disks + mddev->delta_disks);
}
static int raid5_start_reshape(mddev_t *mddev)
{
raid5_conf_t *conf = mddev->private;
mdk_rdev_t *rdev;
int spares = 0;
int added_devices = 0;
unsigned long flags;
if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
return -EBUSY;
if (!check_stripe_cache(mddev))
return -ENOSPC;
list_for_each_entry(rdev, &mddev->disks, same_set)
if (rdev->raid_disk < 0 &&
!test_bit(Faulty, &rdev->flags))
spares++;
if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded)
/* Not enough devices even to make a degraded array
* of that size
*/
return -EINVAL;
/* Refuse to reduce size of the array. Any reductions in
* array size must be through explicit setting of array_size
* attribute.
*/
if (raid5_size(mddev, 0, conf->raid_disks + mddev->delta_disks)
< mddev->array_sectors) {
printk(KERN_ERR "md: %s: array size must be reduced "
"before number of disks\n", mdname(mddev));
return -EINVAL;
}
atomic_set(&conf->reshape_stripes, 0);
spin_lock_irq(&conf->device_lock);
conf->previous_raid_disks = conf->raid_disks;
conf->raid_disks += mddev->delta_disks;
conf->prev_chunk_sectors = conf->chunk_sectors;
conf->chunk_sectors = mddev->new_chunk_sectors;
conf->prev_algo = conf->algorithm;
conf->algorithm = mddev->new_layout;
if (mddev->delta_disks < 0)
conf->reshape_progress = raid5_size(mddev, 0, 0);
else
conf->reshape_progress = 0;
conf->reshape_safe = conf->reshape_progress;
conf->generation++;
spin_unlock_irq(&conf->device_lock);
/* Add some new drives, as many as will fit.
* We know there are enough to make the newly sized array work.
*/
list_for_each_entry(rdev, &mddev->disks, same_set)
if (rdev->raid_disk < 0 &&
!test_bit(Faulty, &rdev->flags)) {
if (raid5_add_disk(mddev, rdev) == 0) {
char nm[20];
set_bit(In_sync, &rdev->flags);
added_devices++;
rdev->recovery_offset = 0;
sprintf(nm, "rd%d", rdev->raid_disk);
if (sysfs_create_link(&mddev->kobj,
&rdev->kobj, nm))
printk(KERN_WARNING
"raid5: failed to create "
" link %s for %s\n",
nm, mdname(mddev));
} else
break;
}
if (mddev->delta_disks > 0) {
spin_lock_irqsave(&conf->device_lock, flags);
mddev->degraded = (conf->raid_disks - conf->previous_raid_disks)
- added_devices;
spin_unlock_irqrestore(&conf->device_lock, flags);
}
mddev->raid_disks = conf->raid_disks;
mddev->reshape_position = 0;
set_bit(MD_CHANGE_DEVS, &mddev->flags);
clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
mddev->sync_thread = md_register_thread(md_do_sync, mddev,
"%s_reshape");
if (!mddev->sync_thread) {
mddev->recovery = 0;
spin_lock_irq(&conf->device_lock);
mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks;
conf->reshape_progress = MaxSector;
spin_unlock_irq(&conf->device_lock);
return -EAGAIN;
}
conf->reshape_checkpoint = jiffies;
md_wakeup_thread(mddev->sync_thread);
md_new_event(mddev);
return 0;
}
/* This is called from the reshape thread and should make any
* changes needed in 'conf'
*/
static void end_reshape(raid5_conf_t *conf)
{
if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
spin_lock_irq(&conf->device_lock);
conf->previous_raid_disks = conf->raid_disks;
conf->reshape_progress = MaxSector;
spin_unlock_irq(&conf->device_lock);
wake_up(&conf->wait_for_overlap);
/* read-ahead size must cover two whole stripes, which is
* 2 * (datadisks) * chunksize where 'n' is the number of raid devices
*/
{
int data_disks = conf->raid_disks - conf->max_degraded;
int stripe = data_disks * ((conf->chunk_sectors << 9)
/ PAGE_SIZE);
if (conf->mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
conf->mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
}
}
}
/* This is called from the raid5d thread with mddev_lock held.
* It makes config changes to the device.
*/
static void raid5_finish_reshape(mddev_t *mddev)
{
struct block_device *bdev;
raid5_conf_t *conf = mddev->private;
if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
if (mddev->delta_disks > 0) {
md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
set_capacity(mddev->gendisk, mddev->array_sectors);
mddev->changed = 1;
bdev = bdget_disk(mddev->gendisk, 0);
if (bdev) {
mutex_lock(&bdev->bd_inode->i_mutex);
i_size_write(bdev->bd_inode,
(loff_t)mddev->array_sectors << 9);
mutex_unlock(&bdev->bd_inode->i_mutex);
bdput(bdev);
}
} else {
int d;
mddev->degraded = conf->raid_disks;
for (d = 0; d < conf->raid_disks ; d++)
if (conf->disks[d].rdev &&
test_bit(In_sync,
&conf->disks[d].rdev->flags))
mddev->degraded--;
for (d = conf->raid_disks ;
d < conf->raid_disks - mddev->delta_disks;
d++)
raid5_remove_disk(mddev, d);
}
mddev->layout = conf->algorithm;
mddev->chunk_sectors = conf->chunk_sectors;
mddev->reshape_position = MaxSector;
mddev->delta_disks = 0;
}
}
static void raid5_quiesce(mddev_t *mddev, int state)
{
raid5_conf_t *conf = mddev->private;
switch(state) {
case 2: /* resume for a suspend */
wake_up(&conf->wait_for_overlap);
break;
case 1: /* stop all writes */
spin_lock_irq(&conf->device_lock);
conf->quiesce = 1;
wait_event_lock_irq(conf->wait_for_stripe,
atomic_read(&conf->active_stripes) == 0 &&
atomic_read(&conf->active_aligned_reads) == 0,
conf->device_lock, /* nothing */);
spin_unlock_irq(&conf->device_lock);
break;
case 0: /* re-enable writes */
spin_lock_irq(&conf->device_lock);
conf->quiesce = 0;
wake_up(&conf->wait_for_stripe);
wake_up(&conf->wait_for_overlap);
spin_unlock_irq(&conf->device_lock);
break;
}
}
static void *raid5_takeover_raid1(mddev_t *mddev)
{
int chunksect;
if (mddev->raid_disks != 2 ||
mddev->degraded > 1)
return ERR_PTR(-EINVAL);
/* Should check if there are write-behind devices? */
chunksect = 64*2; /* 64K by default */
/* The array must be an exact multiple of chunksize */
while (chunksect && (mddev->array_sectors & (chunksect-1)))
chunksect >>= 1;
if ((chunksect<<9) < STRIPE_SIZE)
/* array size does not allow a suitable chunk size */
return ERR_PTR(-EINVAL);
mddev->new_level = 5;
mddev->new_layout = ALGORITHM_LEFT_SYMMETRIC;
mddev->new_chunk_sectors = chunksect;
return setup_conf(mddev);
}
static void *raid5_takeover_raid6(mddev_t *mddev)
{
int new_layout;
switch (mddev->layout) {
case ALGORITHM_LEFT_ASYMMETRIC_6:
new_layout = ALGORITHM_LEFT_ASYMMETRIC;
break;
case ALGORITHM_RIGHT_ASYMMETRIC_6:
new_layout = ALGORITHM_RIGHT_ASYMMETRIC;
break;
case ALGORITHM_LEFT_SYMMETRIC_6:
new_layout = ALGORITHM_LEFT_SYMMETRIC;
break;
case ALGORITHM_RIGHT_SYMMETRIC_6:
new_layout = ALGORITHM_RIGHT_SYMMETRIC;
break;
case ALGORITHM_PARITY_0_6:
new_layout = ALGORITHM_PARITY_0;
break;
case ALGORITHM_PARITY_N:
new_layout = ALGORITHM_PARITY_N;
break;
default:
return ERR_PTR(-EINVAL);
}
mddev->new_level = 5;
mddev->new_layout = new_layout;
mddev->delta_disks = -1;
mddev->raid_disks -= 1;
return setup_conf(mddev);
}
static int raid5_check_reshape(mddev_t *mddev)
{
/* For a 2-drive array, the layout and chunk size can be changed
* immediately as not restriping is needed.
* For larger arrays we record the new value - after validation
* to be used by a reshape pass.
*/
raid5_conf_t *conf = mddev->private;
int new_chunk = mddev->new_chunk_sectors;
if (mddev->new_layout >= 0 && !algorithm_valid_raid5(mddev->new_layout))
return -EINVAL;
if (new_chunk > 0) {
if (!is_power_of_2(new_chunk))
return -EINVAL;
if (new_chunk < (PAGE_SIZE>>9))
return -EINVAL;
if (mddev->array_sectors & (new_chunk-1))
/* not factor of array size */
return -EINVAL;
}
/* They look valid */
if (mddev->raid_disks == 2) {
/* can make the change immediately */
if (mddev->new_layout >= 0) {
conf->algorithm = mddev->new_layout;
mddev->layout = mddev->new_layout;
}
if (new_chunk > 0) {
conf->chunk_sectors = new_chunk ;
mddev->chunk_sectors = new_chunk;
}
set_bit(MD_CHANGE_DEVS, &mddev->flags);
md_wakeup_thread(mddev->thread);
}
return check_reshape(mddev);
}
static int raid6_check_reshape(mddev_t *mddev)
{
int new_chunk = mddev->new_chunk_sectors;
if (mddev->new_layout >= 0 && !algorithm_valid_raid6(mddev->new_layout))
return -EINVAL;
if (new_chunk > 0) {
if (!is_power_of_2(new_chunk))
return -EINVAL;
if (new_chunk < (PAGE_SIZE >> 9))
return -EINVAL;
if (mddev->array_sectors & (new_chunk-1))
/* not factor of array size */
return -EINVAL;
}
/* They look valid */
return check_reshape(mddev);
}
static void *raid5_takeover(mddev_t *mddev)
{
/* raid5 can take over:
* raid0 - if all devices are the same - make it a raid4 layout
* raid1 - if there are two drives. We need to know the chunk size
* raid4 - trivial - just use a raid4 layout.
* raid6 - Providing it is a *_6 layout
*/
if (mddev->level == 1)
return raid5_takeover_raid1(mddev);
if (mddev->level == 4) {
mddev->new_layout = ALGORITHM_PARITY_N;
mddev->new_level = 5;
return setup_conf(mddev);
}
if (mddev->level == 6)
return raid5_takeover_raid6(mddev);
return ERR_PTR(-EINVAL);
}
static struct mdk_personality raid5_personality;
static void *raid6_takeover(mddev_t *mddev)
{
/* Currently can only take over a raid5. We map the
* personality to an equivalent raid6 personality
* with the Q block at the end.
*/
int new_layout;
if (mddev->pers != &raid5_personality)
return ERR_PTR(-EINVAL);
if (mddev->degraded > 1)
return ERR_PTR(-EINVAL);
if (mddev->raid_disks > 253)
return ERR_PTR(-EINVAL);
if (mddev->raid_disks < 3)
return ERR_PTR(-EINVAL);
switch (mddev->layout) {
case ALGORITHM_LEFT_ASYMMETRIC:
new_layout = ALGORITHM_LEFT_ASYMMETRIC_6;
break;
case ALGORITHM_RIGHT_ASYMMETRIC:
new_layout = ALGORITHM_RIGHT_ASYMMETRIC_6;
break;
case ALGORITHM_LEFT_SYMMETRIC:
new_layout = ALGORITHM_LEFT_SYMMETRIC_6;
break;
case ALGORITHM_RIGHT_SYMMETRIC:
new_layout = ALGORITHM_RIGHT_SYMMETRIC_6;
break;
case ALGORITHM_PARITY_0:
new_layout = ALGORITHM_PARITY_0_6;
break;
case ALGORITHM_PARITY_N:
new_layout = ALGORITHM_PARITY_N;
break;
default:
return ERR_PTR(-EINVAL);
}
mddev->new_level = 6;
mddev->new_layout = new_layout;
mddev->delta_disks = 1;
mddev->raid_disks += 1;
return setup_conf(mddev);
}
static struct mdk_personality raid6_personality =
{
.name = "raid6",
.level = 6,
.owner = THIS_MODULE,
.make_request = make_request,
.run = run,
.stop = stop,
.status = status,
.error_handler = error,
.hot_add_disk = raid5_add_disk,
.hot_remove_disk= raid5_remove_disk,
.spare_active = raid5_spare_active,
.sync_request = sync_request,
.resize = raid5_resize,
.size = raid5_size,
.check_reshape = raid6_check_reshape,
.start_reshape = raid5_start_reshape,
.finish_reshape = raid5_finish_reshape,
.quiesce = raid5_quiesce,
.takeover = raid6_takeover,
};
static struct mdk_personality raid5_personality =
{
.name = "raid5",
.level = 5,
.owner = THIS_MODULE,
.make_request = make_request,
.run = run,
.stop = stop,
.status = status,
.error_handler = error,
.hot_add_disk = raid5_add_disk,
.hot_remove_disk= raid5_remove_disk,
.spare_active = raid5_spare_active,
.sync_request = sync_request,
.resize = raid5_resize,
.size = raid5_size,
.check_reshape = raid5_check_reshape,
.start_reshape = raid5_start_reshape,
.finish_reshape = raid5_finish_reshape,
.quiesce = raid5_quiesce,
.takeover = raid5_takeover,
};
static struct mdk_personality raid4_personality =
{
.name = "raid4",
.level = 4,
.owner = THIS_MODULE,
.make_request = make_request,
.run = run,
.stop = stop,
.status = status,
.error_handler = error,
.hot_add_disk = raid5_add_disk,
.hot_remove_disk= raid5_remove_disk,
.spare_active = raid5_spare_active,
.sync_request = sync_request,
.resize = raid5_resize,
.size = raid5_size,
.check_reshape = raid5_check_reshape,
.start_reshape = raid5_start_reshape,
.finish_reshape = raid5_finish_reshape,
.quiesce = raid5_quiesce,
};
static int __init raid5_init(void)
{
register_md_personality(&raid6_personality);
register_md_personality(&raid5_personality);
register_md_personality(&raid4_personality);
return 0;
}
static void raid5_exit(void)
{
unregister_md_personality(&raid6_personality);
unregister_md_personality(&raid5_personality);
unregister_md_personality(&raid4_personality);
}
module_init(raid5_init);
module_exit(raid5_exit);
MODULE_LICENSE("GPL");
MODULE_ALIAS("md-personality-4"); /* RAID5 */
MODULE_ALIAS("md-raid5");
MODULE_ALIAS("md-raid4");
MODULE_ALIAS("md-level-5");
MODULE_ALIAS("md-level-4");
MODULE_ALIAS("md-personality-8"); /* RAID6 */
MODULE_ALIAS("md-raid6");
MODULE_ALIAS("md-level-6");
/* This used to be two separate modules, they were: */
MODULE_ALIAS("raid5");
MODULE_ALIAS("raid6");
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