Viewing file:  raid5.c (52.15 KB) -rw-r--r--
Select action/file-type:
 (+) |  (+) |  (+) | Code (+) | Session (+) |  (+) | SDB (+) |  (+) |  (+) |  (+) |  (+) |  (+) |
/*
* raid5.c : Multiple Devices driver for Linux
* Copyright (C) 1996, 1997 Ingo Molnar, Miguel de Icaza, Gadi Oxman
* Copyright (C) 1999, 2000 Ingo Molnar
*
* RAID-5 management functions.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* You should have received a copy of the GNU General Public License
* (for example /usr/src/linux/COPYING); if not, write to the Free
* Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/config.h>
#include <linux/module.h>
#include <linux/locks.h>
#include <linux/slab.h>
#include <linux/raid/raid5.h>
#include <asm/bitops.h>
#include <asm/atomic.h>
static mdk_personality_t raid5_personality;
/*
* Stripe cache
*/
#define NR_STRIPES 256
#define IO_THRESHOLD 1
#define HASH_PAGES 1
#define HASH_PAGES_ORDER 0
#define NR_HASH (HASH_PAGES * PAGE_SIZE / sizeof(struct stripe_head *))
#define HASH_MASK (NR_HASH - 1)
#define stripe_hash(conf, sect) ((conf)->stripe_hashtbl[((sect) / ((conf)->buffer_size >> 9)) & HASH_MASK])
/*
* The following can be used to debug the driver
*/
#define RAID5_DEBUG 0
#define RAID5_PARANOIA 1
#if RAID5_PARANOIA && CONFIG_SMP
# define CHECK_DEVLOCK() if (!spin_is_locked(&conf->device_lock)) BUG()
#else
# define CHECK_DEVLOCK()
#endif
#if RAID5_DEBUG
#define PRINTK(x...) printk(x)
#define inline
#define __inline__
#else
#define PRINTK(x...) do { } while (0)
#endif
static void print_raid5_conf (raid5_conf_t *conf);
static inline void __release_stripe(raid5_conf_t *conf, struct stripe_head *sh)
{
if (atomic_dec_and_test(&sh->count)) {
if (!list_empty(&sh->lru))
BUG();
if (atomic_read(&conf->active_stripes)==0)
BUG();
if (test_bit(STRIPE_HANDLE, &sh->state)) {
if (test_bit(STRIPE_DELAYED, &sh->state))
list_add_tail(&sh->lru, &conf->delayed_list);
else
list_add_tail(&sh->lru, &conf->handle_list);
md_wakeup_thread(conf->thread);
} else {
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->thread);
}
list_add_tail(&sh->lru, &conf->inactive_list);
atomic_dec(&conf->active_stripes);
if (!conf->inactive_blocked ||
atomic_read(&conf->active_stripes) < (NR_STRIPES*3/4))
wake_up(&conf->wait_for_stripe);
}
}
}
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 void remove_hash(struct stripe_head *sh)
{
PRINTK("remove_hash(), stripe %lu\n", sh->sector);
if (sh->hash_pprev) {
if (sh->hash_next)
sh->hash_next->hash_pprev = sh->hash_pprev;
*sh->hash_pprev = sh->hash_next;
sh->hash_pprev = NULL;
}
}
static __inline__ void insert_hash(raid5_conf_t *conf, struct stripe_head *sh)
{
struct stripe_head **shp = &stripe_hash(conf, sh->sector);
PRINTK("insert_hash(), stripe %lu\n",sh->sector);
CHECK_DEVLOCK();
if ((sh->hash_next = *shp) != NULL)
(*shp)->hash_pprev = &sh->hash_next;
*shp = sh;
sh->hash_pprev = shp;
}
/* 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 buffer_head *bh;
int i;
for (i=0; i<num ; i++) {
bh = sh->bh_cache[i];
if (!bh)
return;
sh->bh_cache[i] = NULL;
free_page((unsigned long) bh->b_data);
kfree(bh);
}
}
static int grow_buffers(struct stripe_head *sh, int num, int b_size, int priority)
{
struct buffer_head *bh;
int i;
for (i=0; i<num; i++) {
struct page *page;
bh = kmalloc(sizeof(struct buffer_head), priority);
if (!bh)
return 1;
memset(bh, 0, sizeof (struct buffer_head));
init_waitqueue_head(&bh->b_wait);
if ((page = alloc_page(priority)))
bh->b_data = page_address(page);
else {
kfree(bh);
return 1;
}
atomic_set(&bh->b_count, 0);
bh->b_page = page;
sh->bh_cache[i] = bh;
}
return 0;
}
static struct buffer_head *raid5_build_block (struct stripe_head *sh, int i);
static inline void init_stripe(struct stripe_head *sh, unsigned long sector)
{
raid5_conf_t *conf = sh->raid_conf;
int disks = conf->raid_disks, i;
if (atomic_read(&sh->count) != 0)
BUG();
if (test_bit(STRIPE_HANDLE, &sh->state))
BUG();
CHECK_DEVLOCK();
PRINTK("init_stripe called, stripe %lu\n", sh->sector);
remove_hash(sh);
sh->sector = sector;
sh->size = conf->buffer_size;
sh->state = 0;
for (i=disks; i--; ) {
if (sh->bh_read[i] || sh->bh_write[i] || sh->bh_written[i] ||
buffer_locked(sh->bh_cache[i])) {
printk("sector=%lx i=%d %p %p %p %d\n",
sh->sector, i, sh->bh_read[i],
sh->bh_write[i], sh->bh_written[i],
buffer_locked(sh->bh_cache[i]));
BUG();
}
clear_bit(BH_Uptodate, &sh->bh_cache[i]->b_state);
raid5_build_block(sh, i);
}
insert_hash(conf, sh);
}
/* the buffer size has changed, so unhash all stripes
* as active stripes complete, they will go onto inactive list
*/
static void shrink_stripe_cache(raid5_conf_t *conf)
{
int i;
CHECK_DEVLOCK();
if (atomic_read(&conf->active_stripes))
BUG();
for (i=0; i < NR_HASH; i++) {
struct stripe_head *sh;
while ((sh = conf->stripe_hashtbl[i]))
remove_hash(sh);
}
}
static struct stripe_head *__find_stripe(raid5_conf_t *conf, unsigned long sector)
{
struct stripe_head *sh;
CHECK_DEVLOCK();
PRINTK("__find_stripe, sector %lu\n", sector);
for (sh = stripe_hash(conf, sector); sh; sh = sh->hash_next)
if (sh->sector == sector)
return sh;
PRINTK("__stripe %lu not in cache\n", sector);
return NULL;
}
static struct stripe_head *get_active_stripe(raid5_conf_t *conf, unsigned long sector, int size, int noblock)
{
struct stripe_head *sh;
PRINTK("get_stripe, sector %lu\n", sector);
md_spin_lock_irq(&conf->device_lock);
do {
if (conf->buffer_size == 0 ||
(size && size != conf->buffer_size)) {
/* either the size is being changed (buffer_size==0) or
* we need to change it.
* If size==0, we can proceed as soon as buffer_size gets set.
* If size>0, we can proceed when active_stripes reaches 0, or
* when someone else sets the buffer_size to size.
* If someone sets the buffer size to something else, we will need to
* assert that we want to change it again
*/
int oldsize = conf->buffer_size;
PRINTK("get_stripe %ld/%d buffer_size is %d, %d active\n", sector, size, conf->buffer_size, atomic_read(&conf->active_stripes));
if (size==0)
wait_event_lock_irq(conf->wait_for_stripe,
conf->buffer_size,
conf->device_lock);
else {
while (conf->buffer_size != size && atomic_read(&conf->active_stripes)) {
conf->buffer_size = 0;
wait_event_lock_irq(conf->wait_for_stripe,
atomic_read(&conf->active_stripes)==0 || conf->buffer_size,
conf->device_lock);
PRINTK("waited and now %ld/%d buffer_size is %d - %d active\n", sector, size,
conf->buffer_size, atomic_read(&conf->active_stripes));
}
if (conf->buffer_size != size) {
PRINTK("raid5: switching cache buffer size, %d --> %d\n", oldsize, size);
shrink_stripe_cache(conf);
if (size==0) BUG();
conf->buffer_size = size;
PRINTK("size now %d\n", conf->buffer_size);
}
}
}
if (size == 0)
sector -= sector & ((conf->buffer_size>>9)-1);
sh = __find_stripe(conf, sector);
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) < (NR_STRIPES *3/4)
|| !conf->inactive_blocked),
conf->device_lock);
conf->inactive_blocked = 0;
} else
init_stripe(sh, sector);
} else {
if (atomic_read(&sh->count)) {
if (!list_empty(&sh->lru))
BUG();
} else {
if (!test_bit(STRIPE_HANDLE, &sh->state))
atomic_inc(&conf->active_stripes);
if (list_empty(&sh->lru))
BUG();
list_del_init(&sh->lru);
}
}
} while (sh == NULL);
if (sh)
atomic_inc(&sh->count);
md_spin_unlock_irq(&conf->device_lock);
return sh;
}
static int grow_stripes(raid5_conf_t *conf, int num, int priority)
{
struct stripe_head *sh;
while (num--) {
sh = kmalloc(sizeof(struct stripe_head), priority);
if (!sh)
return 1;
memset(sh, 0, sizeof(*sh));
sh->raid_conf = conf;
sh->lock = SPIN_LOCK_UNLOCKED;
if (grow_buffers(sh, conf->raid_disks, PAGE_SIZE, priority)) {
shrink_buffers(sh, conf->raid_disks);
kfree(sh);
return 1;
}
/* 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 0;
}
static void shrink_stripes(raid5_conf_t *conf, int num)
{
struct stripe_head *sh;
while (num--) {
spin_lock_irq(&conf->device_lock);
sh = get_free_stripe(conf);
spin_unlock_irq(&conf->device_lock);
if (!sh)
break;
if (atomic_read(&sh->count))
BUG();
shrink_buffers(sh, conf->raid_disks);
kfree(sh);
atomic_dec(&conf->active_stripes);
}
}
static void raid5_end_read_request (struct buffer_head * bh, int uptodate)
{
struct stripe_head *sh = bh->b_private;
raid5_conf_t *conf = sh->raid_conf;
int disks = conf->raid_disks, i;
unsigned long flags;
for (i=0 ; i<disks; i++)
if (bh == sh->bh_cache[i])
break;
PRINTK("end_read_request %lu/%d, count: %d, uptodate %d.\n", sh->sector, i, atomic_read(&sh->count), uptodate);
if (i == disks) {
BUG();
return;
}
if (uptodate) {
struct buffer_head *buffer;
spin_lock_irqsave(&conf->device_lock, flags);
/* we can return a buffer if we bypassed the cache or
* if the top buffer is not in highmem. If there are
* multiple buffers, leave the extra work to
* handle_stripe
*/
buffer = sh->bh_read[i];
if (buffer &&
(!PageHighMem(buffer->b_page)
|| buffer->b_page == bh->b_page )
) {
sh->bh_read[i] = buffer->b_reqnext;
buffer->b_reqnext = NULL;
} else
buffer = NULL;
spin_unlock_irqrestore(&conf->device_lock, flags);
if (sh->bh_page[i]==NULL)
set_bit(BH_Uptodate, &bh->b_state);
if (buffer) {
if (buffer->b_page != bh->b_page)
memcpy(buffer->b_data, bh->b_data, bh->b_size);
buffer->b_end_io(buffer, 1);
}
} else {
md_error(conf->mddev, bh->b_dev);
clear_bit(BH_Uptodate, &bh->b_state);
}
/* must restore b_page before unlocking buffer... */
if (sh->bh_page[i]) {
bh->b_page = sh->bh_page[i];
bh->b_data = page_address(bh->b_page);
sh->bh_page[i] = NULL;
clear_bit(BH_Uptodate, &bh->b_state);
}
clear_bit(BH_Lock, &bh->b_state);
set_bit(STRIPE_HANDLE, &sh->state);
release_stripe(sh);
}
static void raid5_end_write_request (struct buffer_head *bh, int uptodate)
{
struct stripe_head *sh = bh->b_private;
raid5_conf_t *conf = sh->raid_conf;
int disks = conf->raid_disks, i;
unsigned long flags;
for (i=0 ; i<disks; i++)
if (bh == sh->bh_cache[i])
break;
PRINTK("end_write_request %lu/%d, count %d, uptodate: %d.\n", sh->sector, i, atomic_read(&sh->count), uptodate);
if (i == disks) {
BUG();
return;
}
md_spin_lock_irqsave(&conf->device_lock, flags);
if (!uptodate)
md_error(conf->mddev, bh->b_dev);
clear_bit(BH_Lock, &bh->b_state);
set_bit(STRIPE_HANDLE, &sh->state);
__release_stripe(conf, sh);
md_spin_unlock_irqrestore(&conf->device_lock, flags);
}
static struct buffer_head *raid5_build_block (struct stripe_head *sh, int i)
{
raid5_conf_t *conf = sh->raid_conf;
struct buffer_head *bh = sh->bh_cache[i];
unsigned long block = sh->sector / (sh->size >> 9);
init_buffer(bh, raid5_end_read_request, sh);
bh->b_dev = conf->disks[i].dev;
bh->b_blocknr = block;
bh->b_state = (1 << BH_Req) | (1 << BH_Mapped);
bh->b_size = sh->size;
bh->b_list = BUF_LOCKED;
return bh;
}
static int raid5_error (mddev_t *mddev, kdev_t dev)
{
raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
mdp_super_t *sb = mddev->sb;
struct disk_info *disk;
int i;
PRINTK("raid5_error called\n");
for (i = 0, disk = conf->disks; i < conf->raid_disks; i++, disk++) {
if (disk->dev == dev) {
if (disk->operational) {
disk->operational = 0;
mark_disk_faulty(sb->disks+disk->number);
mark_disk_nonsync(sb->disks+disk->number);
mark_disk_inactive(sb->disks+disk->number);
sb->active_disks--;
sb->working_disks--;
sb->failed_disks++;
mddev->sb_dirty = 1;
conf->working_disks--;
conf->failed_disks++;
md_wakeup_thread(conf->thread);
printk (KERN_ALERT
"raid5: Disk failure on %s, disabling device."
" Operation continuing on %d devices\n",
partition_name (dev), conf->working_disks);
}
return 0;
}
}
/*
* handle errors in spares (during reconstruction)
*/
if (conf->spare) {
disk = conf->spare;
if (disk->dev == dev) {
printk (KERN_ALERT
"raid5: Disk failure on spare %s\n",
partition_name (dev));
if (!conf->spare->operational) {
/* probably a SET_DISK_FAULTY ioctl */
return -EIO;
}
disk->operational = 0;
disk->write_only = 0;
conf->spare = NULL;
mark_disk_faulty(sb->disks+disk->number);
mark_disk_nonsync(sb->disks+disk->number);
mark_disk_inactive(sb->disks+disk->number);
sb->spare_disks--;
sb->working_disks--;
sb->failed_disks++;
mddev->sb_dirty = 1;
md_wakeup_thread(conf->thread);
return 0;
}
}
MD_BUG();
return -EIO;
}
/*
* Input: a 'big' sector number,
* Output: index of the data and parity disk, and the sector # in them.
*/
static unsigned long raid5_compute_sector(unsigned long r_sector, unsigned int raid_disks,
unsigned int data_disks, unsigned int * dd_idx,
unsigned int * pd_idx, raid5_conf_t *conf)
{
unsigned long stripe;
unsigned long chunk_number;
unsigned int chunk_offset;
unsigned long new_sector;
int sectors_per_chunk = conf->chunk_size >> 9;
/* First compute the information on this sector */
/*
* Compute the chunk number and the sector offset inside the chunk
*/
chunk_number = r_sector / sectors_per_chunk;
chunk_offset = r_sector % sectors_per_chunk;
/*
* 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.
*/
if (conf->level == 4)
*pd_idx = data_disks;
else switch (conf->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;
default:
printk ("raid5: unsupported algorithm %d\n", conf->algorithm);
}
/*
* Finally, compute the new sector number
*/
new_sector = stripe * sectors_per_chunk + chunk_offset;
return new_sector;
}
#if 0
static unsigned long compute_blocknr(struct stripe_head *sh, int i)
{
raid5_conf_t *conf = sh->raid_conf;
int raid_disks = conf->raid_disks, data_disks = raid_disks - 1;
unsigned long new_sector = sh->sector, check;
int sectors_per_chunk = conf->chunk_size >> 9;
unsigned long stripe = new_sector / sectors_per_chunk;
int chunk_offset = new_sector % sectors_per_chunk;
int chunk_number, dummy1, dummy2, dd_idx = i;
unsigned long r_sector, blocknr;
switch (conf->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;
default:
printk ("raid5: unsupported algorithm %d\n", conf->algorithm);
}
chunk_number = stripe * data_disks + i;
r_sector = chunk_number * sectors_per_chunk + chunk_offset;
blocknr = r_sector / (sh->size >> 9);
check = raid5_compute_sector (r_sector, raid_disks, data_disks, &dummy1, &dummy2, conf);
if (check != sh->sector || dummy1 != dd_idx || dummy2 != sh->pd_idx) {
printk("compute_blocknr: map not correct\n");
return 0;
}
return blocknr;
}
#endif
#define check_xor() do { \
if (count == MAX_XOR_BLOCKS) { \
xor_block(count, bh_ptr); \
count = 1; \
} \
} while(0)
static void compute_block(struct stripe_head *sh, int dd_idx)
{
raid5_conf_t *conf = sh->raid_conf;
int i, count, disks = conf->raid_disks;
struct buffer_head *bh_ptr[MAX_XOR_BLOCKS], *bh;
PRINTK("compute_block, stripe %lu, idx %d\n", sh->sector, dd_idx);
memset(sh->bh_cache[dd_idx]->b_data, 0, sh->size);
bh_ptr[0] = sh->bh_cache[dd_idx];
count = 1;
for (i = disks ; i--; ) {
if (i == dd_idx)
continue;
bh = sh->bh_cache[i];
if (buffer_uptodate(bh))
bh_ptr[count++] = bh;
else
printk("compute_block() %d, stripe %lu, %d not present\n", dd_idx, sh->sector, i);
check_xor();
}
if (count != 1)
xor_block(count, bh_ptr);
set_bit(BH_Uptodate, &sh->bh_cache[dd_idx]->b_state);
}
static void compute_parity(struct stripe_head *sh, int method)
{
raid5_conf_t *conf = sh->raid_conf;
int i, pd_idx = sh->pd_idx, disks = conf->raid_disks, count;
struct buffer_head *bh_ptr[MAX_XOR_BLOCKS];
struct buffer_head *chosen[MD_SB_DISKS];
PRINTK("compute_parity, stripe %lu, method %d\n", sh->sector, method);
memset(chosen, 0, sizeof(chosen));
count = 1;
bh_ptr[0] = sh->bh_cache[pd_idx];
switch(method) {
case READ_MODIFY_WRITE:
if (!buffer_uptodate(sh->bh_cache[pd_idx]))
BUG();
for (i=disks ; i-- ;) {
if (i==pd_idx)
continue;
if (sh->bh_write[i] &&
buffer_uptodate(sh->bh_cache[i])) {
bh_ptr[count++] = sh->bh_cache[i];
chosen[i] = sh->bh_write[i];
sh->bh_write[i] = sh->bh_write[i]->b_reqnext;
chosen[i]->b_reqnext = sh->bh_written[i];
sh->bh_written[i] = chosen[i];
check_xor();
}
}
break;
case RECONSTRUCT_WRITE:
memset(sh->bh_cache[pd_idx]->b_data, 0, sh->size);
for (i= disks; i-- ;)
if (i!=pd_idx && sh->bh_write[i]) {
chosen[i] = sh->bh_write[i];
sh->bh_write[i] = sh->bh_write[i]->b_reqnext;
chosen[i]->b_reqnext = sh->bh_written[i];
sh->bh_written[i] = chosen[i];
}
break;
case CHECK_PARITY:
break;
}
if (count>1) {
xor_block(count, bh_ptr);
count = 1;
}
for (i = disks; i--;)
if (chosen[i]) {
struct buffer_head *bh = sh->bh_cache[i];
char *bdata;
bdata = bh_kmap(chosen[i]);
memcpy(bh->b_data,
bdata,sh->size);
bh_kunmap(chosen[i]);
set_bit(BH_Lock, &bh->b_state);
mark_buffer_uptodate(bh, 1);
}
switch(method) {
case RECONSTRUCT_WRITE:
case CHECK_PARITY:
for (i=disks; i--;)
if (i != pd_idx) {
bh_ptr[count++] = sh->bh_cache[i];
check_xor();
}
break;
case READ_MODIFY_WRITE:
for (i = disks; i--;)
if (chosen[i]) {
bh_ptr[count++] = sh->bh_cache[i];
check_xor();
}
}
if (count != 1)
xor_block(count, bh_ptr);
if (method != CHECK_PARITY) {
mark_buffer_uptodate(sh->bh_cache[pd_idx], 1);
set_bit(BH_Lock, &sh->bh_cache[pd_idx]->b_state);
} else
mark_buffer_uptodate(sh->bh_cache[pd_idx], 0);
}
static void add_stripe_bh (struct stripe_head *sh, struct buffer_head *bh, int dd_idx, int rw)
{
struct buffer_head **bhp;
raid5_conf_t *conf = sh->raid_conf;
PRINTK("adding bh b#%lu to stripe s#%lu\n", bh->b_blocknr, sh->sector);
spin_lock(&sh->lock);
spin_lock_irq(&conf->device_lock);
bh->b_reqnext = NULL;
if (rw == READ)
bhp = &sh->bh_read[dd_idx];
else
bhp = &sh->bh_write[dd_idx];
while (*bhp) {
printk(KERN_NOTICE "raid5: multiple %d requests for sector %ld\n", rw, sh->sector);
bhp = & (*bhp)->b_reqnext;
}
*bhp = bh;
spin_unlock_irq(&conf->device_lock);
spin_unlock(&sh->lock);
PRINTK("added bh b#%lu to stripe s#%lu, disk %d.\n", bh->b_blocknr, sh->sector, dd_idx);
}
/*
* 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
*
* Parity calculations are done inside the stripe lock
* buffers are taken off read_list or write_list, and bh_cache buffers
* get BH_Lock set before the stripe lock is released.
*
*/
static void handle_stripe(struct stripe_head *sh)
{
raid5_conf_t *conf = sh->raid_conf;
int disks = conf->raid_disks;
struct buffer_head *return_ok= NULL, *return_fail = NULL;
int action[MD_SB_DISKS];
int i;
int syncing;
int locked=0, uptodate=0, to_read=0, to_write=0, failed=0, written=0;
int failed_num=0;
struct buffer_head *bh;
PRINTK("handling stripe %ld, cnt=%d, pd_idx=%d\n", sh->sector, atomic_read(&sh->count), sh->pd_idx);
memset(action, 0, sizeof(action));
spin_lock(&sh->lock);
clear_bit(STRIPE_HANDLE, &sh->state);
clear_bit(STRIPE_DELAYED, &sh->state);
syncing = test_bit(STRIPE_SYNCING, &sh->state);
/* Now to look around and see what can be done */
for (i=disks; i--; ) {
bh = sh->bh_cache[i];
PRINTK("check %d: state 0x%lx read %p write %p written %p\n", i, bh->b_state, sh->bh_read[i], sh->bh_write[i], sh->bh_written[i]);
/* maybe we can reply to a read */
if (buffer_uptodate(bh) && sh->bh_read[i]) {
struct buffer_head *rbh, *rbh2;
PRINTK("Return read for disc %d\n", i);
spin_lock_irq(&conf->device_lock);
rbh = sh->bh_read[i];
sh->bh_read[i] = NULL;
spin_unlock_irq(&conf->device_lock);
while (rbh) {
char *bdata;
bdata = bh_kmap(rbh);
memcpy(bdata, bh->b_data, bh->b_size);
bh_kunmap(rbh);
rbh2 = rbh->b_reqnext;
rbh->b_reqnext = return_ok;
return_ok = rbh;
rbh = rbh2;
}
}
/* now count some things */
if (buffer_locked(bh)) locked++;
if (buffer_uptodate(bh)) uptodate++;
if (sh->bh_read[i]) to_read++;
if (sh->bh_write[i]) to_write++;
if (sh->bh_written[i]) written++;
if (!conf->disks[i].operational) {
failed++;
failed_num = i;
}
}
PRINTK("locked=%d uptodate=%d to_read=%d to_write=%d failed=%d failed_num=%d\n",
locked, uptodate, to_read, to_write, failed, failed_num);
/* check if the array has lost two devices and, if so, some requests might
* need to be failed
*/
if (failed > 1 && to_read+to_write) {
for (i=disks; i--; ) {
/* fail all writes first */
if (sh->bh_write[i]) to_write--;
while ((bh = sh->bh_write[i])) {
sh->bh_write[i] = bh->b_reqnext;
bh->b_reqnext = return_fail;
return_fail = bh;
}
/* fail any reads if this device is non-operational */
if (!conf->disks[i].operational) {
spin_lock_irq(&conf->device_lock);
if (sh->bh_read[i]) to_read--;
while ((bh = sh->bh_read[i])) {
sh->bh_read[i] = bh->b_reqnext;
bh->b_reqnext = return_fail;
return_fail = bh;
}
spin_unlock_irq(&conf->device_lock);
}
}
}
if (failed > 1 && syncing) {
md_done_sync(conf->mddev, (sh->size>>9) - sh->sync_redone,0);
clear_bit(STRIPE_SYNCING, &sh->state);
syncing = 0;
}
/* might be able to return some write requests if the parity block
* is safe, or on a failed drive
*/
bh = sh->bh_cache[sh->pd_idx];
if ( written &&
( (conf->disks[sh->pd_idx].operational && !buffer_locked(bh) && buffer_uptodate(bh))
|| (failed == 1 && failed_num == sh->pd_idx))
) {
/* any written block on a uptodate or failed drive can be returned */
for (i=disks; i--; )
if (sh->bh_written[i]) {
bh = sh->bh_cache[i];
if (!conf->disks[sh->pd_idx].operational ||
(!buffer_locked(bh) && buffer_uptodate(bh)) ) {
/* maybe we can return some write requests */
struct buffer_head *wbh, *wbh2;
PRINTK("Return write for disc %d\n", i);
wbh = sh->bh_written[i];
sh->bh_written[i] = NULL;
while (wbh) {
wbh2 = wbh->b_reqnext;
wbh->b_reqnext = return_ok;
return_ok = wbh;
wbh = wbh2;
}
}
}
}
/* Now we might consider reading some blocks, either to check/generate
* parity, or to satisfy requests
*/
if (to_read || (syncing && (uptodate+failed < disks))) {
for (i=disks; i--;) {
bh = sh->bh_cache[i];
if (!buffer_locked(bh) && !buffer_uptodate(bh) &&
(sh->bh_read[i] || syncing || (failed && sh->bh_read[failed_num]))) {
/* we would like to get this block, possibly
* by computing it, but we might not be able to
*/
if (uptodate == disks-1) {
PRINTK("Computing block %d\n", i);
compute_block(sh, i);
uptodate++;
} else if (conf->disks[i].operational) {
set_bit(BH_Lock, &bh->b_state);
action[i] = READ+1;
/* if I am just reading this block and we don't have
a failed drive, or any pending writes then sidestep the cache */
if (sh->bh_page[i]) BUG();
if (sh->bh_read[i] && !sh->bh_read[i]->b_reqnext &&
! syncing && !failed && !to_write) {
sh->bh_page[i] = sh->bh_cache[i]->b_page;
sh->bh_cache[i]->b_page = sh->bh_read[i]->b_page;
sh->bh_cache[i]->b_data = sh->bh_read[i]->b_data;
}
locked++;
PRINTK("Reading block %d (sync=%d)\n", i, syncing);
if (syncing)
md_sync_acct(conf->disks[i].dev, bh->b_size>>9);
}
}
}
set_bit(STRIPE_HANDLE, &sh->state);
}
/* now to consider writing and what else, if anything should be read */
if (to_write) {
int rmw=0, rcw=0;
for (i=disks ; i--;) {
/* would I have to read this buffer for read_modify_write */
bh = sh->bh_cache[i];
if ((sh->bh_write[i] || i == sh->pd_idx) &&
(!buffer_locked(bh) || sh->bh_page[i]) &&
!buffer_uptodate(bh)) {
if (conf->disks[i].operational
/* && !(conf->resync_parity && i == sh->pd_idx) */
)
rmw++;
else rmw += 2*disks; /* cannot read it */
}
/* Would I have to read this buffer for reconstruct_write */
if (!sh->bh_write[i] && i != sh->pd_idx &&
(!buffer_locked(bh) || sh->bh_page[i]) &&
!buffer_uptodate(bh)) {
if (conf->disks[i].operational) rcw++;
else rcw += 2*disks;
}
}
PRINTK("for sector %ld, rmw=%d rcw=%d\n", 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--;) {
bh = sh->bh_cache[i];
if ((sh->bh_write[i] || i == sh->pd_idx) &&
!buffer_locked(bh) && !buffer_uptodate(bh) &&
conf->disks[i].operational) {
if (test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
{
PRINTK("Read_old block %d for r-m-w\n", i);
set_bit(BH_Lock, &bh->b_state);
action[i] = READ+1;
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--;) {
bh = sh->bh_cache[i];
if (!sh->bh_write[i] && i != sh->pd_idx &&
!buffer_locked(bh) && !buffer_uptodate(bh) &&
conf->disks[i].operational) {
if (test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
{
PRINTK("Read_old block %d for Reconstruct\n", i);
set_bit(BH_Lock, &bh->b_state);
action[i] = READ+1;
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 */
if (locked == 0 && (rcw == 0 ||rmw == 0)) {
PRINTK("Computing parity...\n");
compute_parity(sh, rcw==0 ? RECONSTRUCT_WRITE : READ_MODIFY_WRITE);
/* now every locked buffer is ready to be written */
for (i=disks; i--;)
if (buffer_locked(sh->bh_cache[i])) {
PRINTK("Writing block %d\n", i);
locked++;
action[i] = WRITE+1;
if (!conf->disks[i].operational
|| (i==sh->pd_idx && 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->thread);
}
}
}
/* 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 (syncing && locked == 0 &&
!test_bit(STRIPE_INSYNC, &sh->state) && failed <= 1) {
set_bit(STRIPE_HANDLE, &sh->state);
if (failed == 0) {
if (uptodate != disks)
BUG();
compute_parity(sh, CHECK_PARITY);
uptodate--;
bh = sh->bh_cache[sh->pd_idx];
if ((*(u32*)bh->b_data) == 0 &&
!memcmp(bh->b_data, bh->b_data+4, bh->b_size-4)) {
/* parity is correct (on disc, not in buffer any more) */
set_bit(STRIPE_INSYNC, &sh->state);
}
}
if (!test_bit(STRIPE_INSYNC, &sh->state)) {
struct disk_info *spare;
if (failed==0)
failed_num = sh->pd_idx;
/* should be able to compute the missing block and write it to spare */
if (!buffer_uptodate(sh->bh_cache[failed_num])) {
if (uptodate+1 != disks)
BUG();
compute_block(sh, failed_num);
uptodate++;
}
if (uptodate != disks)
BUG();
bh = sh->bh_cache[failed_num];
set_bit(BH_Lock, &bh->b_state);
action[failed_num] = WRITE+1;
locked++;
set_bit(STRIPE_INSYNC, &sh->state);
if (conf->disks[failed_num].operational)
md_sync_acct(conf->disks[failed_num].dev, bh->b_size>>9);
else if ((spare=conf->spare))
md_sync_acct(spare->dev, bh->b_size>>9);
}
}
if (syncing && locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) {
md_done_sync(conf->mddev, (sh->size>>9) - sh->sync_redone,1);
clear_bit(STRIPE_SYNCING, &sh->state);
}
spin_unlock(&sh->lock);
while ((bh=return_ok)) {
return_ok = bh->b_reqnext;
bh->b_reqnext = NULL;
bh->b_end_io(bh, 1);
}
while ((bh=return_fail)) {
return_fail = bh->b_reqnext;
bh->b_reqnext = NULL;
bh->b_end_io(bh, 0);
}
for (i=disks; i-- ;)
if (action[i]) {
struct buffer_head *bh = sh->bh_cache[i];
struct disk_info *spare = conf->spare;
int skip = 0;
if (action[i] == READ+1)
bh->b_end_io = raid5_end_read_request;
else
bh->b_end_io = raid5_end_write_request;
if (conf->disks[i].operational)
bh->b_dev = conf->disks[i].dev;
else if (spare && action[i] == WRITE+1)
bh->b_dev = spare->dev;
else skip=1;
if (!skip) {
PRINTK("for %ld schedule op %d on disc %d\n", sh->sector, action[i]-1, i);
atomic_inc(&sh->count);
bh->b_rdev = bh->b_dev;
bh->b_rsector = bh->b_blocknr * (bh->b_size>>9);
generic_make_request(action[i]-1, bh);
} else {
PRINTK("skip op %d on disc %d for sector %ld\n", action[i]-1, i, sh->sector);
clear_bit(BH_Lock, &bh->b_state);
set_bit(STRIPE_HANDLE, &sh->state);
}
}
}
static inline 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->handle_list);
}
}
}
static void raid5_unplug_device(void *data)
{
raid5_conf_t *conf = (raid5_conf_t *)data;
unsigned long flags;
spin_lock_irqsave(&conf->device_lock, flags);
raid5_activate_delayed(conf);
conf->plugged = 0;
md_wakeup_thread(conf->thread);
spin_unlock_irqrestore(&conf->device_lock, flags);
}
static inline void raid5_plug_device(raid5_conf_t *conf)
{
spin_lock_irq(&conf->device_lock);
if (list_empty(&conf->delayed_list))
if (!conf->plugged) {
conf->plugged = 1;
queue_task(&conf->plug_tq, &tq_disk);
}
spin_unlock_irq(&conf->device_lock);
}
static int raid5_make_request (mddev_t *mddev, int rw, struct buffer_head * bh)
{
raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
const unsigned int raid_disks = conf->raid_disks;
const unsigned int data_disks = raid_disks - 1;
unsigned int dd_idx, pd_idx;
unsigned long new_sector;
int read_ahead = 0;
struct stripe_head *sh;
if (rw == READA) {
rw = READ;
read_ahead=1;
}
new_sector = raid5_compute_sector(bh->b_rsector,
raid_disks, data_disks, &dd_idx, &pd_idx, conf);
PRINTK("raid5_make_request, sector %lu\n", new_sector);
sh = get_active_stripe(conf, new_sector, bh->b_size, read_ahead);
if (sh) {
sh->pd_idx = pd_idx;
add_stripe_bh(sh, bh, dd_idx, rw);
raid5_plug_device(conf);
handle_stripe(sh);
release_stripe(sh);
} else
bh->b_end_io(bh, test_bit(BH_Uptodate, &bh->b_state));
return 0;
}
/*
* Determine correct block size for this device.
*/
unsigned int device_bsize (kdev_t dev)
{
unsigned int i, correct_size;
correct_size = BLOCK_SIZE;
if (blksize_size[MAJOR(dev)]) {
i = blksize_size[MAJOR(dev)][MINOR(dev)];
if (i)
correct_size = i;
}
return correct_size;
}
static int raid5_sync_request (mddev_t *mddev, unsigned long sector_nr)
{
raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
struct stripe_head *sh;
int sectors_per_chunk = conf->chunk_size >> 9;
unsigned long stripe = sector_nr/sectors_per_chunk;
int chunk_offset = sector_nr % sectors_per_chunk;
int dd_idx, pd_idx;
unsigned long first_sector;
int raid_disks = conf->raid_disks;
int data_disks = raid_disks-1;
int redone = 0;
int bufsize;
sh = get_active_stripe(conf, sector_nr, 0, 0);
bufsize = sh->size;
redone = sector_nr - sh->sector;
first_sector = raid5_compute_sector(stripe*data_disks*sectors_per_chunk
+ chunk_offset, raid_disks, data_disks, &dd_idx, &pd_idx, conf);
sh->pd_idx = pd_idx;
spin_lock(&sh->lock);
set_bit(STRIPE_SYNCING, &sh->state);
clear_bit(STRIPE_INSYNC, &sh->state);
sh->sync_redone = redone;
spin_unlock(&sh->lock);
handle_stripe(sh);
release_stripe(sh);
return (bufsize>>9)-redone;
}
/*
* 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 (void *data)
{
struct stripe_head *sh;
raid5_conf_t *conf = data;
mddev_t *mddev = conf->mddev;
int handled;
PRINTK("+++ raid5d active\n");
handled = 0;
if (mddev->sb_dirty)
md_update_sb(mddev);
md_spin_lock_irq(&conf->device_lock);
while (1) {
struct list_head *first;
if (list_empty(&conf->handle_list) &&
atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD &&
!conf->plugged &&
!list_empty(&conf->delayed_list))
raid5_activate_delayed(conf);
if (list_empty(&conf->handle_list))
break;
first = conf->handle_list.next;
sh = list_entry(first, struct stripe_head, lru);
list_del_init(first);
atomic_inc(&sh->count);
if (atomic_read(&sh->count)!= 1)
BUG();
md_spin_unlock_irq(&conf->device_lock);
handled++;
handle_stripe(sh);
release_stripe(sh);
md_spin_lock_irq(&conf->device_lock);
}
PRINTK("%d stripes handled\n", handled);
md_spin_unlock_irq(&conf->device_lock);
PRINTK("--- raid5d inactive\n");
}
/*
* Private kernel thread for parity reconstruction after an unclean
* shutdown. Reconstruction on spare drives in case of a failed drive
* is done by the generic mdsyncd.
*/
static void raid5syncd (void *data)
{
raid5_conf_t *conf = data;
mddev_t *mddev = conf->mddev;
if (!conf->resync_parity)
return;
if (conf->resync_parity == 2)
return;
down(&mddev->recovery_sem);
if (md_do_sync(mddev,NULL)) {
up(&mddev->recovery_sem);
printk("raid5: resync aborted!\n");
return;
}
conf->resync_parity = 0;
up(&mddev->recovery_sem);
printk("raid5: resync finished.\n");
}
static int raid5_run (mddev_t *mddev)
{
raid5_conf_t *conf;
int i, j, raid_disk, memory;
mdp_super_t *sb = mddev->sb;
mdp_disk_t *desc;
mdk_rdev_t *rdev;
struct disk_info *disk;
struct md_list_head *tmp;
int start_recovery = 0;
MOD_INC_USE_COUNT;
if (sb->level != 5 && sb->level != 4) {
printk("raid5: md%d: raid level not set to 4/5 (%d)\n", mdidx(mddev), sb->level);
MOD_DEC_USE_COUNT;
return -EIO;
}
mddev->private = kmalloc (sizeof (raid5_conf_t), GFP_KERNEL);
if ((conf = mddev->private) == NULL)
goto abort;
memset (conf, 0, sizeof (*conf));
conf->mddev = mddev;
if ((conf->stripe_hashtbl = (struct stripe_head **) md__get_free_pages(GFP_ATOMIC, HASH_PAGES_ORDER)) == NULL)
goto abort;
memset(conf->stripe_hashtbl, 0, HASH_PAGES * PAGE_SIZE);
conf->device_lock = MD_SPIN_LOCK_UNLOCKED;
md_init_waitqueue_head(&conf->wait_for_stripe);
INIT_LIST_HEAD(&conf->handle_list);
INIT_LIST_HEAD(&conf->delayed_list);
INIT_LIST_HEAD(&conf->inactive_list);
atomic_set(&conf->active_stripes, 0);
atomic_set(&conf->preread_active_stripes, 0);
conf->buffer_size = PAGE_SIZE; /* good default for rebuild */
conf->plugged = 0;
conf->plug_tq.sync = 0;
conf->plug_tq.routine = &raid5_unplug_device;
conf->plug_tq.data = conf;
PRINTK("raid5_run(md%d) called.\n", mdidx(mddev));
ITERATE_RDEV(mddev,rdev,tmp) {
/*
* This is important -- we are using the descriptor on
* the disk only to get a pointer to the descriptor on
* the main superblock, which might be more recent.
*/
desc = sb->disks + rdev->desc_nr;
raid_disk = desc->raid_disk;
disk = conf->disks + raid_disk;
if (disk_faulty(desc)) {
printk(KERN_ERR "raid5: disabled device %s (errors detected)\n", partition_name(rdev->dev));
if (!rdev->faulty) {
MD_BUG();
goto abort;
}
disk->number = desc->number;
disk->raid_disk = raid_disk;
disk->dev = rdev->dev;
disk->operational = 0;
disk->write_only = 0;
disk->spare = 0;
disk->used_slot = 1;
continue;
}
if (disk_active(desc)) {
if (!disk_sync(desc)) {
printk(KERN_ERR "raid5: disabled device %s (not in sync)\n", partition_name(rdev->dev));
MD_BUG();
goto abort;
}
if (raid_disk > sb->raid_disks) {
printk(KERN_ERR "raid5: disabled device %s (inconsistent descriptor)\n", partition_name(rdev->dev));
continue;
}
if (disk->operational) {
printk(KERN_ERR "raid5: disabled device %s (device %d already operational)\n", partition_name(rdev->dev), raid_disk);
continue;
}
printk(KERN_INFO "raid5: device %s operational as raid disk %d\n", partition_name(rdev->dev), raid_disk);
disk->number = desc->number;
disk->raid_disk = raid_disk;
disk->dev = rdev->dev;
disk->operational = 1;
disk->used_slot = 1;
conf->working_disks++;
} else {
/*
* Must be a spare disk ..
*/
printk(KERN_INFO "raid5: spare disk %s\n", partition_name(rdev->dev));
disk->number = desc->number;
disk->raid_disk = raid_disk;
disk->dev = rdev->dev;
disk->operational = 0;
disk->write_only = 0;
disk->spare = 1;
disk->used_slot = 1;
}
}
for (i = 0; i < MD_SB_DISKS; i++) {
desc = sb->disks + i;
raid_disk = desc->raid_disk;
disk = conf->disks + raid_disk;
if (disk_faulty(desc) && (raid_disk < sb->raid_disks) &&
!conf->disks[raid_disk].used_slot) {
disk->number = desc->number;
disk->raid_disk = raid_disk;
disk->dev = MKDEV(0,0);
disk->operational = 0;
disk->write_only = 0;
disk->spare = 0;
disk->used_slot = 1;
}
}
conf->raid_disks = sb->raid_disks;
/*
* 0 for a fully functional array, 1 for a degraded array.
*/
conf->failed_disks = conf->raid_disks - conf->working_disks;
conf->mddev = mddev;
conf->chunk_size = sb->chunk_size;
conf->level = sb->level;
conf->algorithm = sb->layout;
conf->max_nr_stripes = NR_STRIPES;
#if 0
for (i = 0; i < conf->raid_disks; i++) {
if (!conf->disks[i].used_slot) {
MD_BUG();
goto abort;
}
}
#endif
if (!conf->chunk_size || conf->chunk_size % 4) {
printk(KERN_ERR "raid5: invalid chunk size %d for md%d\n", conf->chunk_size, mdidx(mddev));
goto abort;
}
if (conf->algorithm > ALGORITHM_RIGHT_SYMMETRIC) {
printk(KERN_ERR "raid5: unsupported parity algorithm %d for md%d\n", conf->algorithm, mdidx(mddev));
goto abort;
}
if (conf->failed_disks > 1) {
printk(KERN_ERR "raid5: not enough operational devices for md%d (%d/%d failed)\n", mdidx(mddev), conf->failed_disks, conf->raid_disks);
goto abort;
}
if (conf->working_disks != sb->raid_disks) {
printk(KERN_ALERT "raid5: md%d, not all disks are operational -- trying to recover array\n", mdidx(mddev));
start_recovery = 1;
}
{
const char * name = "raid5d";
conf->thread = md_register_thread(raid5d, conf, name);
if (!conf->thread) {
printk(KERN_ERR "raid5: couldn't allocate thread for md%d\n", mdidx(mddev));
goto abort;
}
}
memory = conf->max_nr_stripes * (sizeof(struct stripe_head) +
conf->raid_disks * ((sizeof(struct buffer_head) + PAGE_SIZE))) / 1024;
if (grow_stripes(conf, conf->max_nr_stripes, GFP_KERNEL)) {
printk(KERN_ERR "raid5: couldn't allocate %dkB for buffers\n", memory);
shrink_stripes(conf, conf->max_nr_stripes);
goto abort;
} else
printk(KERN_INFO "raid5: allocated %dkB for md%d\n", memory, mdidx(mddev));
/*
* Regenerate the "device is in sync with the raid set" bit for
* each device.
*/
for (i = 0; i < MD_SB_DISKS ; i++) {
mark_disk_nonsync(sb->disks + i);
for (j = 0; j < sb->raid_disks; j++) {
if (!conf->disks[j].operational)
continue;
if (sb->disks[i].number == conf->disks[j].number)
mark_disk_sync(sb->disks + i);
}
}
sb->active_disks = conf->working_disks;
if (sb->active_disks == sb->raid_disks)
printk("raid5: raid level %d set md%d active with %d out of %d devices, algorithm %d\n", conf->level, mdidx(mddev), sb->active_disks, sb->raid_disks, conf->algorithm);
else
printk(KERN_ALERT "raid5: raid level %d set md%d active with %d out of %d devices, algorithm %d\n", conf->level, mdidx(mddev), sb->active_disks, sb->raid_disks, conf->algorithm);
if (!start_recovery && !(sb->state & (1 << MD_SB_CLEAN))) {
const char * name = "raid5syncd";
conf->resync_thread = md_register_thread(raid5syncd, conf,name);
if (!conf->resync_thread) {
printk(KERN_ERR "raid5: couldn't allocate thread for md%d\n", mdidx(mddev));
goto abort;
}
printk("raid5: raid set md%d not clean; reconstructing parity\n", mdidx(mddev));
conf->resync_parity = 1;
md_wakeup_thread(conf->resync_thread);
}
print_raid5_conf(conf);
if (start_recovery)
md_recover_arrays();
print_raid5_conf(conf);
/* Ok, everything is just fine now */
return (0);
abort:
if (conf) {
print_raid5_conf(conf);
if (conf->stripe_hashtbl)
free_pages((unsigned long) conf->stripe_hashtbl,
HASH_PAGES_ORDER);
kfree(conf);
}
mddev->private = NULL;
printk(KERN_ALERT "raid5: failed to run raid set md%d\n", mdidx(mddev));
MOD_DEC_USE_COUNT;
return -EIO;
}
static int raid5_stop_resync (mddev_t *mddev)
{
raid5_conf_t *conf = mddev_to_conf(mddev);
mdk_thread_t *thread = conf->resync_thread;
if (thread) {
if (conf->resync_parity) {
conf->resync_parity = 2;
md_interrupt_thread(thread);
printk(KERN_INFO "raid5: parity resync was not fully finished, restarting next time.\n");
return 1;
}
return 0;
}
return 0;
}
static int raid5_restart_resync (mddev_t *mddev)
{
raid5_conf_t *conf = mddev_to_conf(mddev);
if (conf->resync_parity) {
if (!conf->resync_thread) {
MD_BUG();
return 0;
}
printk("raid5: waking up raid5resync.\n");
conf->resync_parity = 1;
md_wakeup_thread(conf->resync_thread);
return 1;
} else
printk("raid5: no restart-resync needed.\n");
return 0;
}
static int raid5_stop (mddev_t *mddev)
{
raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
if (conf->resync_thread)
md_unregister_thread(conf->resync_thread);
md_unregister_thread(conf->thread);
shrink_stripes(conf, conf->max_nr_stripes);
free_pages((unsigned long) conf->stripe_hashtbl, HASH_PAGES_ORDER);
kfree(conf);
mddev->private = NULL;
MOD_DEC_USE_COUNT;
return 0;
}
#if RAID5_DEBUG
static void print_sh (struct stripe_head *sh)
{
int i;
printk("sh %lu, size %d, pd_idx %d, state %ld.\n", sh->sector, sh->size, sh->pd_idx, sh->state);
printk("sh %lu, count %d.\n", sh->sector, atomic_read(&sh->count));
printk("sh %lu, ", sh->sector);
for (i = 0; i < MD_SB_DISKS; i++) {
if (sh->bh_cache[i])
printk("(cache%d: %p %ld) ", i, sh->bh_cache[i], sh->bh_cache[i]->b_state);
}
printk("\n");
}
static void printall (raid5_conf_t *conf)
{
struct stripe_head *sh;
int i;
md_spin_lock_irq(&conf->device_lock);
for (i = 0; i < NR_HASH; i++) {
sh = conf->stripe_hashtbl[i];
for (; sh; sh = sh->hash_next) {
if (sh->raid_conf != conf)
continue;
print_sh(sh);
}
}
md_spin_unlock_irq(&conf->device_lock);
PRINTK("--- raid5d inactive\n");
}
#endif
static int raid5_status (char *page, mddev_t *mddev)
{
raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
mdp_super_t *sb = mddev->sb;
int sz = 0, i;
sz += sprintf (page+sz, " level %d, %dk chunk, algorithm %d", sb->level, sb->chunk_size >> 10, sb->layout);
sz += sprintf (page+sz, " [%d/%d] [", conf->raid_disks, conf->working_disks);
for (i = 0; i < conf->raid_disks; i++)
sz += sprintf (page+sz, "%s", conf->disks[i].operational ? "U" : "_");
sz += sprintf (page+sz, "]");
#if RAID5_DEBUG
#define D(x) \
sz += sprintf (page+sz, "<"#x":%d>", atomic_read(&conf->x))
printall(conf);
#endif
return sz;
}
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 fd:%d\n", conf->raid_disks,
conf->working_disks, conf->failed_disks);
#if RAID5_DEBUG
for (i = 0; i < MD_SB_DISKS; i++) {
#else
for (i = 0; i < conf->working_disks+conf->failed_disks; i++) {
#endif
tmp = conf->disks + i;
printk(" disk %d, s:%d, o:%d, n:%d rd:%d us:%d dev:%s\n",
i, tmp->spare,tmp->operational,
tmp->number,tmp->raid_disk,tmp->used_slot,
partition_name(tmp->dev));
}
}
static int raid5_diskop(mddev_t *mddev, mdp_disk_t **d, int state)
{
int err = 0;
int i, failed_disk=-1, spare_disk=-1, removed_disk=-1, added_disk=-1;
raid5_conf_t *conf = mddev->private;
struct disk_info *tmp, *sdisk, *fdisk, *rdisk, *adisk;
mdp_super_t *sb = mddev->sb;
mdp_disk_t *failed_desc, *spare_desc, *added_desc;
mdk_rdev_t *spare_rdev, *failed_rdev;
print_raid5_conf(conf);
md_spin_lock_irq(&conf->device_lock);
/*
* find the disk ...
*/
switch (state) {
case DISKOP_SPARE_ACTIVE:
/*
* Find the failed disk within the RAID5 configuration ...
* (this can only be in the first conf->raid_disks part)
*/
for (i = 0; i < conf->raid_disks; i++) {
tmp = conf->disks + i;
if ((!tmp->operational && !tmp->spare) ||
!tmp->used_slot) {
failed_disk = i;
break;
}
}
/*
* When we activate a spare disk we _must_ have a disk in
* the lower (active) part of the array to replace.
*/
if ((failed_disk == -1) || (failed_disk >= conf->raid_disks)) {
MD_BUG();
err = 1;
goto abort;
}
/* fall through */
case DISKOP_SPARE_WRITE:
case DISKOP_SPARE_INACTIVE:
/*
* Find the spare disk ... (can only be in the 'high'
* area of the array)
*/
for (i = conf->raid_disks; i < MD_SB_DISKS; i++) {
tmp = conf->disks + i;
if (tmp->spare && tmp->number == (*d)->number) {
spare_disk = i;
break;
}
}
if (spare_disk == -1) {
MD_BUG();
err = 1;
goto abort;
}
break;
case DISKOP_HOT_REMOVE_DISK:
for (i = 0; i < MD_SB_DISKS; i++) {
tmp = conf->disks + i;
if (tmp->used_slot && (tmp->number == (*d)->number)) {
if (tmp->operational) {
err = -EBUSY;
goto abort;
}
removed_disk = i;
break;
}
}
if (removed_disk == -1) {
MD_BUG();
err = 1;
goto abort;
}
break;
case DISKOP_HOT_ADD_DISK:
for (i = conf->raid_disks; i < MD_SB_DISKS; i++) {
tmp = conf->disks + i;
if (!tmp->used_slot) {
added_disk = i;
break;
}
}
if (added_disk == -1) {
MD_BUG();
err = 1;
goto abort;
}
break;
}
switch (state) {
/*
* Switch the spare disk to write-only mode:
*/
case DISKOP_SPARE_WRITE:
if (conf->spare) {
MD_BUG();
err = 1;
goto abort;
}
sdisk = conf->disks + spare_disk;
sdisk->operational = 1;
sdisk->write_only = 1;
conf->spare = sdisk;
break;
/*
* Deactivate a spare disk:
*/
case DISKOP_SPARE_INACTIVE:
sdisk = conf->disks + spare_disk;
sdisk->operational = 0;
sdisk->write_only = 0;
/*
* Was the spare being resynced?
*/
if (conf->spare == sdisk)
conf->spare = NULL;
break;
/*
* Activate (mark read-write) the (now sync) spare disk,
* which means we switch it's 'raid position' (->raid_disk)
* with the failed disk. (only the first 'conf->raid_disks'
* slots are used for 'real' disks and we must preserve this
* property)
*/
case DISKOP_SPARE_ACTIVE:
if (!conf->spare) {
MD_BUG();
err = 1;
goto abort;
}
sdisk = conf->disks + spare_disk;
fdisk = conf->disks + failed_disk;
spare_desc = &sb->disks[sdisk->number];
failed_desc = &sb->disks[fdisk->number];
if (spare_desc != *d) {
MD_BUG();
err = 1;
goto abort;
}
if (spare_desc->raid_disk != sdisk->raid_disk) {
MD_BUG();
err = 1;
goto abort;
}
if (sdisk->raid_disk != spare_disk) {
MD_BUG();
err = 1;
goto abort;
}
if (failed_desc->raid_disk != fdisk->raid_disk) {
MD_BUG();
err = 1;
goto abort;
}
if (fdisk->raid_disk != failed_disk) {
MD_BUG();
err = 1;
goto abort;
}
/*
* do the switch finally
*/
spare_rdev = find_rdev_nr(mddev, spare_desc->number);
failed_rdev = find_rdev_nr(mddev, failed_desc->number);
/* There must be a spare_rdev, but there may not be a
* failed_rdev. That slot might be empty...
*/
spare_rdev->desc_nr = failed_desc->number;
if (failed_rdev)
failed_rdev->desc_nr = spare_desc->number;
xchg_values(*spare_desc, *failed_desc);
xchg_values(*fdisk, *sdisk);
/*
* (careful, 'failed' and 'spare' are switched from now on)
*
* we want to preserve linear numbering and we want to
* give the proper raid_disk number to the now activated
* disk. (this means we switch back these values)
*/
xchg_values(spare_desc->raid_disk, failed_desc->raid_disk);
xchg_values(sdisk->raid_disk, fdisk->raid_disk);
xchg_values(spare_desc->number, failed_desc->number);
xchg_values(sdisk->number, fdisk->number);
*d = failed_desc;
if (sdisk->dev == MKDEV(0,0))
sdisk->used_slot = 0;
/*
* this really activates the spare.
*/
fdisk->spare = 0;
fdisk->write_only = 0;
/*
* if we activate a spare, we definitely replace a
* non-operational disk slot in the 'low' area of
* the disk array.
*/
conf->failed_disks--;
conf->working_disks++;
conf->spare = NULL;
break;
case DISKOP_HOT_REMOVE_DISK:
rdisk = conf->disks + removed_disk;
if (rdisk->spare && (removed_disk < conf->raid_disks)) {
MD_BUG();
err = 1;
goto abort;
}
rdisk->dev = MKDEV(0,0);
rdisk->used_slot = 0;
break;
case DISKOP_HOT_ADD_DISK:
adisk = conf->disks + added_disk;
added_desc = *d;
if (added_disk != added_desc->number) {
MD_BUG();
err = 1;
goto abort;
}
adisk->number = added_desc->number;
adisk->raid_disk = added_desc->raid_disk;
adisk->dev = MKDEV(added_desc->major,added_desc->minor);
adisk->operational = 0;
adisk->write_only = 0;
adisk->spare = 1;
adisk->used_slot = 1;
break;
default:
MD_BUG();
err = 1;
goto abort;
}
abort:
md_spin_unlock_irq(&conf->device_lock);
print_raid5_conf(conf);
return err;
}
static mdk_personality_t raid5_personality=
{
name: "raid5",
make_request: raid5_make_request,
run: raid5_run,
stop: raid5_stop,
status: raid5_status,
error_handler: raid5_error,
diskop: raid5_diskop,
stop_resync: raid5_stop_resync,
restart_resync: raid5_restart_resync,
sync_request: raid5_sync_request
};
static int md__init raid5_init (void)
{
return register_md_personality (RAID5, &raid5_personality);
}
static void raid5_exit (void)
{
unregister_md_personality (RAID5);
}
module_init(raid5_init);
module_exit(raid5_exit);
MODULE_LICENSE("GPL");
|