* 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-5 management functions.
+ * 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
#include <linux/config.h>
#include <linux/module.h>
#include <linux/slab.h>
-#include <linux/raid/raid5.h>
#include <linux/highmem.h>
#include <linux/bitops.h>
#include <linux/kthread.h>
#include <asm/atomic.h>
+#include "raid6.h"
#include <linux/raid/bitmap.h>
#define __inline__
#endif
+#if !RAID6_USE_EMPTY_ZERO_PAGE
+/* In .bss so it's zeroed */
+const char raid6_empty_zero_page[PAGE_SIZE] __attribute__((aligned(256)));
+#endif
+
+static inline int raid6_next_disk(int disk, int raid_disks)
+{
+ disk++;
+ return (disk < raid_disks) ? disk : 0;
+}
static void print_raid5_conf (raid5_conf_t *conf);
static void __release_stripe(raid5_conf_t *conf, 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);
hlist_del_init(&sh->hash);
}
-static void insert_hash(raid5_conf_t *conf, struct stripe_head *sh)
+static inline void insert_hash(raid5_conf_t *conf, struct stripe_head *sh)
{
struct hlist_head *hp = stripe_hash(conf, sh->sector);
(unsigned long long)sh->sector);
remove_hash(sh);
-
+
sh->sector = sector;
sh->pd_idx = pd_idx;
sh->state = 0;
} else {
if (!test_bit(STRIPE_HANDLE, &sh->state))
atomic_inc(&conf->active_stripes);
- if (!list_empty(&sh->lru))
- list_del_init(&sh->lru);
+ if (list_empty(&sh->lru))
+ BUG();
+ list_del_init(&sh->lru);
}
}
} while (sh == NULL);
return 1;
conf->slab_cache = sc;
conf->pool_size = devs;
- while (num--) {
+ while (num--)
if (!grow_one_stripe(conf))
return 1;
- }
return 0;
}
dev->req.bi_private = sh;
dev->flags = 0;
- if (i != sh->pd_idx)
- dev->sector = compute_blocknr(sh, i);
+ dev->sector = compute_blocknr(sh, i);
}
static void error(mddev_t *mddev, mdk_rdev_t *rdev)
" Operation continuing on %d devices\n",
bdevname(rdev->bdev,b), conf->working_disks);
}
-}
+}
/*
* Input: a 'big' sector number,
/*
* Select the parity disk based on the user selected algorithm.
*/
- if (conf->level == 4)
+ switch(conf->level) {
+ case 4:
*pd_idx = data_disks;
- else switch (conf->algorithm) {
+ break;
+ case 5:
+ switch (conf->algorithm) {
case ALGORITHM_LEFT_ASYMMETRIC:
*pd_idx = data_disks - stripe % raid_disks;
if (*dd_idx >= *pd_idx)
default:
printk(KERN_ERR "raid5: unsupported algorithm %d\n",
conf->algorithm);
+ }
+ break;
+ case 6:
+
+ /**** FIX THIS ****/
+ switch (conf->algorithm) {
+ case ALGORITHM_LEFT_ASYMMETRIC:
+ *pd_idx = raid_disks - 1 - (stripe % raid_disks);
+ if (*pd_idx == raid_disks-1)
+ (*dd_idx)++; /* Q D D D P */
+ else if (*dd_idx >= *pd_idx)
+ (*dd_idx) += 2; /* D D P Q D */
+ break;
+ case ALGORITHM_RIGHT_ASYMMETRIC:
+ *pd_idx = stripe % raid_disks;
+ if (*pd_idx == raid_disks-1)
+ (*dd_idx)++; /* Q D D D P */
+ 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);
+ *dd_idx = (*pd_idx + 2 + *dd_idx) % raid_disks;
+ break;
+ case ALGORITHM_RIGHT_SYMMETRIC:
+ *pd_idx = stripe % raid_disks;
+ *dd_idx = (*pd_idx + 2 + *dd_idx) % raid_disks;
+ break;
+ default:
+ printk (KERN_CRIT "raid6: unsupported algorithm %d\n",
+ conf->algorithm);
+ }
+ break;
}
/*
int chunk_number, dummy1, dummy2, dd_idx = i;
sector_t r_sector;
+
chunk_offset = sector_div(new_sector, sectors_per_chunk);
stripe = new_sector;
BUG_ON(new_sector != stripe);
-
- switch (conf->algorithm) {
+ if (i == sh->pd_idx)
+ return 0;
+ switch(conf->level) {
+ case 4: break;
+ case 5:
+ switch (conf->algorithm) {
case ALGORITHM_LEFT_ASYMMETRIC:
case ALGORITHM_RIGHT_ASYMMETRIC:
if (i > sh->pd_idx)
break;
default:
printk(KERN_ERR "raid5: unsupported algorithm %d\n",
+ conf->algorithm);
+ }
+ break;
+ case 6:
+ data_disks = raid_disks - 2;
+ if (i == raid6_next_disk(sh->pd_idx, raid_disks))
+ return 0; /* It is the Q disk */
+ switch (conf->algorithm) {
+ case ALGORITHM_LEFT_ASYMMETRIC:
+ case ALGORITHM_RIGHT_ASYMMETRIC:
+ 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;
+ default:
+ printk (KERN_CRIT "raid6: unsupported algorithm %d\n",
conf->algorithm);
+ }
+ break;
}
chunk_number = stripe * data_disks + i;
/*
- * Copy data between a page in the stripe cache, and a bio.
- * There are no alignment or size guarantees between the page or the
- * bio except that there is some overlap.
- * All iovecs in the bio must be considered.
+ * 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,
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)
set_bit(R5_UPTODATE, &sh->dev[dd_idx].flags);
}
-static void compute_parity(struct stripe_head *sh, int method)
+static void compute_parity5(struct stripe_head *sh, int method)
{
raid5_conf_t *conf = sh->raid_conf;
int i, pd_idx = sh->pd_idx, disks = sh->disks, count;
void *ptr[MAX_XOR_BLOCKS];
struct bio *chosen;
- PRINTK("compute_parity, stripe %llu, method %d\n",
+ PRINTK("compute_parity5, stripe %llu, method %d\n",
(unsigned long long)sh->sector, method);
count = 1;
clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
}
+static void compute_parity6(struct stripe_head *sh, int method)
+{
+ raid6_conf_t *conf = sh->raid_conf;
+ int i, pd_idx = sh->pd_idx, qd_idx, d0_idx, disks = conf->raid_disks, count;
+ struct bio *chosen;
+ /**** FIX THIS: This could be very bad if disks is close to 256 ****/
+ void *ptrs[disks];
+
+ qd_idx = raid6_next_disk(pd_idx, disks);
+ d0_idx = raid6_next_disk(qd_idx, disks);
+
+ PRINTK("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);
+
+ if (sh->dev[i].written) BUG();
+ 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);
+ }
+
+// switch(method) {
+// case RECONSTRUCT_WRITE:
+// case CHECK_PARITY:
+// case UPDATE_PARITY:
+ /* Note that unlike RAID-5, the ordering of the disks matters greatly. */
+ /* FIX: Is this ordering of drives even remotely optimal? */
+ count = 0;
+ i = d0_idx;
+ do {
+ ptrs[count++] = page_address(sh->dev[i].page);
+ if (count <= disks-2 && !test_bit(R5_UPTODATE, &sh->dev[i].flags))
+ printk("block %d/%d not uptodate on parity calc\n", i,count);
+ i = raid6_next_disk(i, disks);
+ } while ( i != d0_idx );
+// break;
+// }
+
+ raid6_call.gen_syndrome(disks, 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)
+{
+ raid6_conf_t *conf = sh->raid_conf;
+ int i, count, disks = conf->raid_disks;
+ void *ptr[MAX_XOR_BLOCKS], *p;
+ int pd_idx = sh->pd_idx;
+ int qd_idx = raid6_next_disk(pd_idx, disks);
+
+ PRINTK("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 {
+ ptr[0] = page_address(sh->dev[dd_idx].page);
+ if (!nozero) memset(ptr[0], 0, STRIPE_SIZE);
+ count = 1;
+ 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 != 1)
+ xor_block(count, STRIPE_SIZE, 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)
+{
+ raid6_conf_t *conf = sh->raid_conf;
+ int i, count, disks = conf->raid_disks;
+ int pd_idx = sh->pd_idx;
+ int qd_idx = raid6_next_disk(pd_idx, disks);
+ int d0_idx = raid6_next_disk(qd_idx, disks);
+ int faila, failb;
+
+ /* faila and failb are disk numbers relative to d0_idx */
+ /* pd_idx become disks-2 and qd_idx become disks-1 */
+ faila = (dd_idx1 < d0_idx) ? dd_idx1+(disks-d0_idx) : dd_idx1-d0_idx;
+ failb = (dd_idx2 < d0_idx) ? dd_idx2+(disks-d0_idx) : dd_idx2-d0_idx;
+
+ BUG_ON(faila == failb);
+ if ( failb < faila ) { int tmp = faila; faila = failb; failb = tmp; }
+
+ PRINTK("compute_block_2, stripe %llu, idx %d,%d (%d,%d)\n",
+ (unsigned long long)sh->sector, dd_idx1, dd_idx2, faila, failb);
+
+ if ( failb == disks-1 ) {
+ /* Q disk is one of the missing disks */
+ if ( faila == disks-2 ) {
+ /* 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 == qd_idx) ? dd_idx2 : dd_idx1, 0);
+ compute_parity6(sh, UPDATE_PARITY); /* Is this necessary? */
+ return;
+ }
+ }
+
+ /* We're missing D+P or D+D; build pointer table */
+ {
+ /**** FIX THIS: This could be very bad if disks is close to 256 ****/
+ void *ptrs[disks];
+
+ count = 0;
+ i = d0_idx;
+ do {
+ ptrs[count++] = page_address(sh->dev[i].page);
+ i = raid6_next_disk(i, disks);
+ if (i != dd_idx1 && i != dd_idx2 &&
+ !test_bit(R5_UPTODATE, &sh->dev[i].flags))
+ printk("compute_2 with missing block %d/%d\n", count, i);
+ } while ( i != d0_idx );
+
+ if ( failb == disks-2 ) {
+ /* We're missing D+P. */
+ raid6_datap_recov(disks, STRIPE_SIZE, faila, ptrs);
+ } else {
+ /* We're missing D+D. */
+ raid6_2data_recov(disks, 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);
+ }
+}
+
+
+
/*
* Each stripe/dev can have one or more bion attached.
- * toread/towrite point to the first in a chain.
+ * 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)
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 int stripe_to_pdidx(sector_t stripe, raid5_conf_t *conf, int disks)
{
int sectors_per_chunk = conf->chunk_size >> 9;
*
*/
-static void handle_stripe(struct stripe_head *sh)
+static void handle_stripe5(struct stripe_head *sh)
{
raid5_conf_t *conf = sh->raid_conf;
int disks = sh->disks;
if (locked == 0 && (rcw == 0 ||rmw == 0) &&
!test_bit(STRIPE_BIT_DELAY, &sh->state)) {
PRINTK("Computing parity...\n");
- compute_parity(sh, rcw==0 ? RECONSTRUCT_WRITE : READ_MODIFY_WRITE);
+ compute_parity5(sh, rcw==0 ? RECONSTRUCT_WRITE : READ_MODIFY_WRITE);
/* now every locked buffer is ready to be written */
for (i=disks; i--;)
if (test_bit(R5_LOCKED, &sh->dev[i].flags)) {
!test_bit(STRIPE_INSYNC, &sh->state)) {
set_bit(STRIPE_HANDLE, &sh->state);
if (failed == 0) {
- char *pagea;
BUG_ON(uptodate != disks);
- compute_parity(sh, CHECK_PARITY);
+ compute_parity5(sh, CHECK_PARITY);
uptodate--;
- pagea = page_address(sh->dev[sh->pd_idx].page);
- if ((*(u32*)pagea) == 0 &&
- !memcmp(pagea, pagea+4, STRIPE_SIZE-4)) {
+ if (page_is_zero(sh->dev[sh->pd_idx].page)) {
/* parity is correct (on disc, not in buffer any more) */
set_bit(STRIPE_INSYNC, &sh->state);
} else {
/* Need to write out all blocks after computing parity */
sh->disks = conf->raid_disks;
sh->pd_idx = stripe_to_pdidx(sh->sector, conf, conf->raid_disks);
- compute_parity(sh, RECONSTRUCT_WRITE);
+ compute_parity5(sh, RECONSTRUCT_WRITE);
for (i= conf->raid_disks; i--;) {
set_bit(R5_LOCKED, &sh->dev[i].flags);
locked++;
}
}
-static void raid5_activate_delayed(raid5_conf_t *conf)
+static void handle_stripe6(struct stripe_head *sh, struct page *tmp_page)
{
- 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);
- }
- }
-}
+ raid6_conf_t *conf = sh->raid_conf;
+ int disks = conf->raid_disks;
+ struct bio *return_bi= NULL;
+ struct bio *bi;
+ int i;
+ int syncing;
+ int locked=0, uptodate=0, to_read=0, to_write=0, failed=0, written=0;
+ int non_overwrite = 0;
+ int failed_num[2] = {0, 0};
+ struct r5dev *dev, *pdev, *qdev;
+ int pd_idx = sh->pd_idx;
+ int qd_idx = raid6_next_disk(pd_idx, disks);
+ int p_failed, q_failed;
-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);
- }
-}
+ PRINTK("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);
-static void unplug_slaves(mddev_t *mddev)
-{
- raid5_conf_t *conf = mddev_to_conf(mddev);
- int i;
+ 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 */
rcu_read_lock();
- for (i=0; i<mddev->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)) {
- request_queue_t *r_queue = bdev_get_queue(rdev->bdev);
+ for (i=disks; i--; ) {
+ mdk_rdev_t *rdev;
+ dev = &sh->dev[i];
+ clear_bit(R5_Insync, &dev->flags);
- atomic_inc(&rdev->nr_pending);
- rcu_read_unlock();
+ PRINTK("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;
+ PRINTK("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 (--rbi->bi_phys_segments == 0) {
+ rbi->bi_next = return_bi;
+ return_bi = rbi;
+ }
+ spin_unlock_irq(&conf->device_lock);
+ rbi = rbi2;
+ }
+ }
- if (r_queue->unplug_fn)
- r_queue->unplug_fn(r_queue);
+ /* now count some things */
+ if (test_bit(R5_LOCKED, &dev->flags)) locked++;
+ if (test_bit(R5_UPTODATE, &dev->flags)) uptodate++;
- rdev_dec_pending(rdev, mddev);
- rcu_read_lock();
+
+ if (dev->toread) to_read++;
+ if (dev->towrite) {
+ to_write++;
+ if (!test_bit(R5_OVERWRITE, &dev->flags))
+ non_overwrite++;
+ }
+ if (dev->written) written++;
+ rdev = rcu_dereference(conf->disks[i].rdev);
+ 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 ( failed < 2 )
+ failed_num[failed] = i;
+ failed++;
+ } else
+ set_bit(R5_Insync, &dev->flags);
}
rcu_read_unlock();
-}
+ PRINTK("locked=%d uptodate=%d to_read=%d"
+ " to_write=%d failed=%d failed_num=%d,%d\n",
+ locked, uptodate, to_read, to_write, failed,
+ failed_num[0], failed_num[1]);
+ /* check if the array has lost >2 devices and, if so, some requests might
+ * need to be failed
+ */
+ if (failed > 2 && to_read+to_write+written) {
+ for (i=disks; i--; ) {
+ int bitmap_end = 0;
-static void raid5_unplug_device(request_queue_t *q)
-{
- mddev_t *mddev = q->queuedata;
- raid5_conf_t *conf = mddev_to_conf(mddev);
- unsigned long flags;
+ 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_irqsave(&conf->device_lock, flags);
+ spin_lock_irq(&conf->device_lock);
+ /* fail all writes first */
+ bi = sh->dev[i].towrite;
+ sh->dev[i].towrite = NULL;
+ if (bi) { to_write--; bitmap_end = 1; }
- if (blk_remove_plug(q)) {
- conf->seq_flush++;
- raid5_activate_delayed(conf);
+ 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 (--bi->bi_phys_segments == 0) {
+ 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 (--bi->bi_phys_segments == 0) {
+ md_write_end(conf->mddev);
+ bi->bi_next = return_bi;
+ return_bi = bi;
+ }
+ bi = bi2;
+ }
+
+ /* fail any reads if this device is non-operational */
+ if (!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) 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 (--bi->bi_phys_segments == 0) {
+ 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 (failed > 2 && syncing) {
+ md_done_sync(conf->mddev, STRIPE_SECTORS,0);
+ clear_bit(STRIPE_SYNCING, &sh->state);
+ 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];
+ p_failed = (failed >= 1 && failed_num[0] == pd_idx)
+ || (failed >= 2 && failed_num[1] == pd_idx);
+ qdev = &sh->dev[qd_idx];
+ q_failed = (failed >= 1 && failed_num[0] == qd_idx)
+ || (failed >= 2 && failed_num[1] == qd_idx);
+
+ if ( written &&
+ ( p_failed || ((test_bit(R5_Insync, &pdev->flags)
+ && !test_bit(R5_LOCKED, &pdev->flags)
+ && test_bit(R5_UPTODATE, &pdev->flags))) ) &&
+ ( q_failed || ((test_bit(R5_Insync, &qdev->flags)
+ && !test_bit(R5_LOCKED, &qdev->flags)
+ && test_bit(R5_UPTODATE, &qdev->flags))) ) ) {
+ /* 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.
+ */
+ 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 */
+ int bitmap_end = 0;
+ struct bio *wbi, *wbi2;
+ PRINTK("Return write for stripe %llu disc %d\n",
+ (unsigned long long)sh->sector, 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 (--wbi->bi_phys_segments == 0) {
+ 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);
+ }
+ }
+ }
+
+ /* 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 (to_read || non_overwrite || (to_write && failed) || (syncing && (uptodate < disks))) {
+ for (i=disks; i--;) {
+ 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)) ||
+ syncing ||
+ (failed >= 1 && (sh->dev[failed_num[0]].toread || to_write)) ||
+ (failed >= 2 && (sh->dev[failed_num[1]].toread || to_write))
+ )
+ ) {
+ /* we would like to get this block, possibly
+ * by computing it, but we might not be able to
+ */
+ if (uptodate == disks-1) {
+ PRINTK("Computing stripe %llu block %d\n",
+ (unsigned long long)sh->sector, i);
+ compute_block_1(sh, i, 0);
+ uptodate++;
+ } else if ( uptodate == disks-2 && 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);
+ PRINTK("Computing stripe %llu blocks %d,%d\n",
+ (unsigned long long)sh->sector, i, other);
+ compute_block_2(sh, i, other);
+ uptodate += 2;
+ } else if (test_bit(R5_Insync, &dev->flags)) {
+ set_bit(R5_LOCKED, &dev->flags);
+ set_bit(R5_Wantread, &dev->flags);
+#if 0
+ /* 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_read[i] && !sh->bh_read[i]->b_reqnext &&
+ ! syncing && !failed && !to_write) {
+ sh->bh_cache[i]->b_page = sh->bh_read[i]->b_page;
+ sh->bh_cache[i]->b_data = sh->bh_read[i]->b_data;
+ }
+#endif
+ locked++;
+ PRINTK("Reading block %d (sync=%d)\n",
+ i, syncing);
+ }
+ }
+ }
+ set_bit(STRIPE_HANDLE, &sh->state);
+ }
+
+ /* now to consider writing and what else, if anything should be read */
+ if (to_write) {
+ int rcw=0, must_compute=0;
+ for (i=disks ; i--;) {
+ 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)
+#if 0
+ || sh->bh_page[i] != bh->b_page
+#endif
+ ) &&
+ !test_bit(R5_UPTODATE, &dev->flags)) {
+ if (test_bit(R5_Insync, &dev->flags)) rcw++;
+ else {
+ PRINTK("raid6: must_compute: disk %d flags=%#lx\n", i, dev->flags);
+ must_compute++;
+ }
+ }
+ }
+ PRINTK("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--;) {
+ dev = &sh->dev[i];
+ if (!test_bit(R5_OVERWRITE, &dev->flags)
+ && !(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))
+ {
+ PRINTK("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);
+ locked++;
+ } else {
+ PRINTK("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 (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 ( failed ) {
+ case 0: BUG();
+ case 1: compute_block_1(sh, failed_num[0], 0); break;
+ case 2: compute_block_2(sh, failed_num[0], failed_num[1]); break;
+ default: BUG(); /* This request should have been failed? */
+ }
+ }
+
+ PRINTK("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)) {
+ PRINTK("Writing stripe %llu block %d\n",
+ (unsigned long long)sh->sector, i);
+ locked++;
+ set_bit(R5_Wantwrite, &sh->dev[i].flags);
+ }
+ /* 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);
+ }
+ }
+ }
+
+ /* 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)) {
+ int update_p = 0, update_q = 0;
+ struct r5dev *dev;
+
+ set_bit(STRIPE_HANDLE, &sh->state);
+
+ BUG_ON(failed>2);
+ BUG_ON(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 (failed == 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 (!q_failed && 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 (failed == 2) {
+ dev = &sh->dev[failed_num[1]];
+ locked++;
+ set_bit(R5_LOCKED, &dev->flags);
+ set_bit(R5_Wantwrite, &dev->flags);
+ }
+ if (failed >= 1) {
+ dev = &sh->dev[failed_num[0]];
+ locked++;
+ set_bit(R5_LOCKED, &dev->flags);
+ set_bit(R5_Wantwrite, &dev->flags);
+ }
+
+ if (update_p) {
+ dev = &sh->dev[pd_idx];
+ locked ++;
+ set_bit(R5_LOCKED, &dev->flags);
+ set_bit(R5_Wantwrite, &dev->flags);
+ }
+ if (update_q) {
+ dev = &sh->dev[qd_idx];
+ 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);
+ }
+ }
+
+ if (syncing && 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 (failed <= 2 && ! conf->mddev->ro)
+ for (i=0; i<failed;i++) {
+ dev = &sh->dev[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);
+ }
+ }
+ }
+ spin_unlock(&sh->lock);
+
+ while ((bi=return_bi)) {
+ int bytes = bi->bi_size;
+
+ return_bi = bi->bi_next;
+ bi->bi_next = NULL;
+ bi->bi_size = 0;
+ bi->bi_end_io(bi, bytes, 0);
+ }
+ 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 = 1;
+ else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
+ rw = 0;
+ else
+ continue;
+
+ bi = &sh->dev[i].req;
+
+ bi->bi_rw = rw;
+ if (rw)
+ 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 (syncing)
+ md_sync_acct(rdev->bdev, STRIPE_SECTORS);
+
+ bi->bi_bdev = rdev->bdev;
+ PRINTK("for %llu schedule op %ld on disc %d\n",
+ (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 == 1)
+ set_bit(STRIPE_DEGRADED, &sh->state);
+ PRINTK("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 void handle_stripe(struct stripe_head *sh, struct page *tmp_page)
+{
+ if (sh->raid_conf->level == 6)
+ handle_stripe6(sh, tmp_page);
+ else
+ 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->handle_list);
+ }
+ }
+}
+
+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_to_conf(mddev);
+ int i;
+
+ rcu_read_lock();
+ for (i=0; i<mddev->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)) {
+ request_queue_t *r_queue = bdev_get_queue(rdev->bdev);
+
+ atomic_inc(&rdev->nr_pending);
+ rcu_read_unlock();
+
+ if (r_queue->unplug_fn)
+ r_queue->unplug_fn(r_queue);
+
+ rdev_dec_pending(rdev, mddev);
+ rcu_read_lock();
+ }
+ }
+ rcu_read_unlock();
+}
+
+static void raid5_unplug_device(request_queue_t *q)
+{
+ mddev_t *mddev = q->queuedata;
+ raid5_conf_t *conf = mddev_to_conf(mddev);
+ 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);
for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
DEFINE_WAIT(w);
- int disks;
+ int disks, data_disks;
retry:
prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
}
spin_unlock_irq(&conf->device_lock);
}
- new_sector = raid5_compute_sector(logical_sector, disks, disks - 1,
+ data_disks = disks - conf->max_degraded;
+
+ new_sector = raid5_compute_sector(logical_sector, disks, data_disks,
&dd_idx, &pd_idx, conf);
PRINTK("raid5: make_request, sector %llu logical %llu\n",
(unsigned long long)new_sector,
}
finish_wait(&conf->wait_for_overlap, &w);
raid5_plug_device(conf);
- handle_stripe(sh);
+ handle_stripe(sh, NULL);
release_stripe(sh);
} else {
/* cannot get stripe for read-ahead, just give-up */
if (remaining == 0) {
int bytes = bi->bi_size;
- if ( bio_data_dir(bi) == WRITE )
+ if ( rw == WRITE )
md_write_end(mddev);
bi->bi_size = 0;
bi->bi_end_io(bi, bytes, 0);
int pd_idx;
sector_t first_sector, last_sector;
int raid_disks = conf->raid_disks;
- int data_disks = raid_disks-1;
+ int data_disks = raid_disks - conf->max_degraded;
sector_t max_sector = mddev->size << 1;
int sync_blocks;
+ int still_degraded = 0;
+ int i;
if (sector_nr >= max_sector) {
/* just being told to finish up .. nothing much to do */
if (mddev->curr_resync < max_sector) /* aborted */
bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
&sync_blocks, 1);
- else /* compelted sync */
+ else /* completed sync */
conf->fullsync = 0;
bitmap_close_sync(mddev->bitmap);
}
return conf->chunk_size>>9;
}
- /* if there is 1 or more failed drives and we are trying
+ /* 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 >= 1 && test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
+ if (mddev->degraded >= (data_disks - raid_disks) &&
+ test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
sector_t rv = (mddev->size << 1) - sector_nr;
*skipped = 1;
return rv;
if (sh == NULL) {
sh = get_active_stripe(conf, sector_nr, raid_disks, pd_idx, 0);
/* make sure we don't swamp the stripe cache if someone else
- * is trying to get access
+ * is trying to get access
*/
schedule_timeout_uninterruptible(1);
}
- bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 0);
- spin_lock(&sh->lock);
+ /* 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<mddev->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);
- handle_stripe(sh);
+ handle_stripe(sh, NULL);
release_stripe(sh);
return STRIPE_SECTORS;
spin_unlock_irq(&conf->device_lock);
handled++;
- handle_stripe(sh);
+ handle_stripe(sh, conf->spare_page);
release_stripe(sh);
spin_lock_irq(&conf->device_lock);
struct disk_info *disk;
struct list_head *tmp;
- if (mddev->level != 5 && mddev->level != 4) {
- printk(KERN_ERR "raid5: %s: raid level not set to 4/5 (%d)\n",
+ if (mddev->level != 5 && mddev->level != 4 && mddev->level != 6) {
+ printk(KERN_ERR "raid5: %s: raid level not set to 4/5/6 (%d)\n",
mdname(mddev), mddev->level);
return -EIO;
}
if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL)
goto abort;
+ if (mddev->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);
}
/*
- * 0 for a fully functional array, 1 for a degraded array.
+ * 0 for a fully functional array, 1 or 2 for a degraded array.
*/
mddev->degraded = conf->failed_disks = conf->raid_disks - conf->working_disks;
conf->mddev = mddev;
conf->chunk_size = mddev->chunk_size;
conf->level = mddev->level;
+ if (conf->level == 6)
+ conf->max_degraded = 2;
+ else
+ conf->max_degraded = 1;
conf->algorithm = mddev->layout;
conf->max_nr_stripes = NR_STRIPES;
conf->expand_progress = mddev->reshape_position;
mddev->size &= ~(mddev->chunk_size/1024 -1);
mddev->resync_max_sectors = mddev->size << 1;
+ if (conf->level == 6 && conf->raid_disks < 4) {
+ printk(KERN_ERR "raid6: not enough configured devices for %s (%d, minimum 4)\n",
+ mdname(mddev), conf->raid_disks);
+ goto abort;
+ }
if (!conf->chunk_size || conf->chunk_size % 4) {
printk(KERN_ERR "raid5: invalid chunk size %d for %s\n",
conf->chunk_size, mdname(mddev));
conf->algorithm, mdname(mddev));
goto abort;
}
- if (mddev->degraded > 1) {
+ if (mddev->degraded > conf->max_degraded) {
printk(KERN_ERR "raid5: not enough operational devices for %s"
" (%d/%d failed)\n",
mdname(mddev), conf->failed_disks, conf->raid_disks);
goto abort;
}
- if (mddev->degraded == 1 &&
+ if (mddev->degraded > 0 &&
mddev->recovery_cp != MaxSector) {
if (mddev->ok_start_degraded)
printk(KERN_WARNING
}
/* read-ahead size must cover two whole stripes, which is
- * 2 * (n-1) * chunksize where 'n' is the number of raid devices
+ * 2 * (datadisks) * chunksize where 'n' is the number of raid devices
*/
{
- int stripe = (mddev->raid_disks-1) *
+ int data_disks = conf->previous_raid_disks - conf->max_degraded;
+ int stripe = data_disks *
(mddev->chunk_size / PAGE_SIZE);
if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
mddev->queue->unplug_fn = raid5_unplug_device;
mddev->queue->issue_flush_fn = raid5_issue_flush;
- mddev->array_size = mddev->size * (conf->previous_raid_disks - 1);
+ mddev->array_size = mddev->size * (conf->previous_raid_disks -
+ conf->max_degraded);
return 0;
abort:
if (conf) {
print_raid5_conf(conf);
+ safe_put_page(conf->spare_page);
kfree(conf->disks);
kfree(conf->stripe_hashtbl);
kfree(conf);
}
#if RAID5_DEBUG
-static void print_sh (struct stripe_head *sh)
+static void print_sh (struct seq_file *seq, struct stripe_head *sh)
{
int i;
- printk("sh %llu, pd_idx %d, state %ld.\n",
- (unsigned long long)sh->sector, sh->pd_idx, sh->state);
- printk("sh %llu, count %d.\n",
- (unsigned long long)sh->sector, atomic_read(&sh->count));
- printk("sh %llu, ", (unsigned long long)sh->sector);
+ 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++) {
- printk("(cache%d: %p %ld) ",
- i, sh->dev[i].page, sh->dev[i].flags);
+ seq_printf(seq, "(cache%d: %p %ld) ",
+ i, sh->dev[i].page, sh->dev[i].flags);
}
- printk("\n");
+ seq_printf(seq, "\n");
}
-static void printall (raid5_conf_t *conf)
+static void printall (struct seq_file *seq, raid5_conf_t *conf)
{
struct stripe_head *sh;
struct hlist_node *hn;
hlist_for_each_entry(sh, hn, &conf->stripe_hashtbl[i], hash) {
if (sh->raid_conf != conf)
continue;
- print_sh(sh);
+ print_sh(seq, sh);
}
}
spin_unlock_irq(&conf->device_lock);
test_bit(In_sync, &conf->disks[i].rdev->flags) ? "U" : "_");
seq_printf (seq, "]");
#if RAID5_DEBUG
-#define D(x) \
- seq_printf (seq, "<"#x":%d>", atomic_read(&conf->x))
- printall(conf);
+ seq_printf (seq, "\n");
+ printall(seq, conf);
#endif
}
int disk;
struct disk_info *p;
- if (mddev->degraded > 1)
+ if (mddev->degraded > conf->max_degraded)
/* no point adding a device */
return 0;
/*
- * find the disk ...
+ * find the disk ... but prefer rdev->saved_raid_disk
+ * if possible.
*/
- for (disk=0; disk < conf->raid_disks; disk++)
+ if (rdev->saved_raid_disk >= 0 &&
+ conf->disks[rdev->saved_raid_disk].rdev == NULL)
+ disk = rdev->saved_raid_disk;
+ else
+ disk = 0;
+ for ( ; disk < conf->raid_disks; disk++)
if ((p=conf->disks + disk)->rdev == NULL) {
clear_bit(In_sync, &rdev->flags);
rdev->raid_disk = disk;
* any io in the removed space completes, but it hardly seems
* worth it.
*/
+ raid5_conf_t *conf = mddev_to_conf(mddev);
+
sectors &= ~((sector_t)mddev->chunk_size/512 - 1);
- mddev->array_size = (sectors * (mddev->raid_disks-1))>>1;
+ mddev->array_size = (sectors * (mddev->raid_disks-conf->max_degraded))>>1;
set_capacity(mddev->gendisk, mddev->array_size << 1);
mddev->changed = 1;
if (sectors/2 > mddev->size && mddev->recovery_cp == MaxSector) {
conf->expand_progress = MaxSector;
spin_unlock_irq(&conf->device_lock);
conf->mddev->reshape_position = MaxSector;
+
+ /* 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 *
+ (conf->mddev->chunk_size / PAGE_SIZE);
+ if (conf->mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
+ conf->mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
+ }
}
}
}
}
+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,
+ .quiesce = raid5_quiesce,
+};
static struct mdk_personality raid5_personality =
{
.name = "raid5",
static int __init raid5_init(void)
{
+ int e;
+
+ e = raid6_select_algo();
+ if ( e )
+ return e;
+ 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_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");
+++ /dev/null
-/*
- * raid6main.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-6 management functions. This code is derived from raid5.c.
- * Last merge from raid5.c bkcvs version 1.79 (kernel 2.6.1).
- *
- * 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.
- */
-
-
-#include <linux/config.h>
-#include <linux/module.h>
-#include <linux/slab.h>
-#include <linux/highmem.h>
-#include <linux/bitops.h>
-#include <asm/atomic.h>
-#include "raid6.h"
-
-#include <linux/raid/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 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 RAID6_DEBUG 0 /* Extremely verbose printk */
-#define RAID6_PARANOIA 1 /* Check spinlocks */
-#define RAID6_DUMPSTATE 0 /* Include stripe cache state in /proc/mdstat */
-#if RAID6_PARANOIA && defined(CONFIG_SMP)
-# define CHECK_DEVLOCK() assert_spin_locked(&conf->device_lock)
-#else
-# define CHECK_DEVLOCK()
-#endif
-
-#define PRINTK(x...) ((void)(RAID6_DEBUG && printk(KERN_DEBUG x)))
-#if RAID6_DEBUG
-#undef inline
-#undef __inline__
-#define inline
-#define __inline__
-#endif
-
-#if !RAID6_USE_EMPTY_ZERO_PAGE
-/* In .bss so it's zeroed */
-const char raid6_empty_zero_page[PAGE_SIZE] __attribute__((aligned(256)));
-#endif
-
-static inline int raid6_next_disk(int disk, int raid_disks)
-{
- disk++;
- return (disk < raid_disks) ? disk : 0;
-}
-
-static void print_raid6_conf (raid6_conf_t *conf);
-
-static void __release_stripe(raid6_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);
- else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
- conf->seq_write == sh->bm_seq)
- list_add_tail(&sh->lru, &conf->bitmap_list);
- else {
- clear_bit(STRIPE_BIT_DELAY, &sh->state);
- list_add_tail(&sh->lru, &conf->handle_list);
- }
- md_wakeup_thread(conf->mddev->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->mddev->thread);
- }
- list_add_tail(&sh->lru, &conf->inactive_list);
- atomic_dec(&conf->active_stripes);
- if (!conf->inactive_blocked ||
- atomic_read(&conf->active_stripes) < (conf->max_nr_stripes*3/4))
- wake_up(&conf->wait_for_stripe);
- }
- }
-}
-static void release_stripe(struct stripe_head *sh)
-{
- raid6_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)
-{
- PRINTK("remove_hash(), stripe %llu\n", (unsigned long long)sh->sector);
-
- hlist_del_init(&sh->hash);
-}
-
-static inline void insert_hash(raid6_conf_t *conf, struct stripe_head *sh)
-{
- struct hlist_head *hp = stripe_hash(conf, sh->sector);
-
- PRINTK("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(raid6_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 raid6_build_block (struct stripe_head *sh, int i);
-
-static void init_stripe(struct stripe_head *sh, sector_t sector, int pd_idx)
-{
- raid6_conf_t *conf = sh->raid_conf;
- int disks = conf->raid_disks, i;
-
- BUG_ON(atomic_read(&sh->count) != 0);
- BUG_ON(test_bit(STRIPE_HANDLE, &sh->state));
-
- CHECK_DEVLOCK();
- PRINTK("init_stripe called, stripe %llu\n",
- (unsigned long long)sh->sector);
-
- remove_hash(sh);
-
- sh->sector = sector;
- sh->pd_idx = pd_idx;
- sh->state = 0;
-
- for (i=disks; i--; ) {
- struct r5dev *dev = &sh->dev[i];
-
- if (dev->toread || dev->towrite || dev->written ||
- test_bit(R5_LOCKED, &dev->flags)) {
- PRINTK("sector=%llx i=%d %p %p %p %d\n",
- (unsigned long long)sh->sector, i, dev->toread,
- dev->towrite, dev->written,
- test_bit(R5_LOCKED, &dev->flags));
- BUG();
- }
- dev->flags = 0;
- raid6_build_block(sh, i);
- }
- insert_hash(conf, sh);
-}
-
-static struct stripe_head *__find_stripe(raid6_conf_t *conf, sector_t sector)
-{
- struct stripe_head *sh;
- struct hlist_node *hn;
-
- CHECK_DEVLOCK();
- PRINTK("__find_stripe, sector %llu\n", (unsigned long long)sector);
- hlist_for_each_entry (sh, hn, stripe_hash(conf, sector), hash)
- if (sh->sector == sector)
- return sh;
- PRINTK("__stripe %llu not in cache\n", (unsigned long long)sector);
- return NULL;
-}
-
-static void unplug_slaves(mddev_t *mddev);
-
-static struct stripe_head *get_active_stripe(raid6_conf_t *conf, sector_t sector,
- int pd_idx, int noblock)
-{
- struct stripe_head *sh;
-
- PRINTK("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,
- conf->device_lock, /* nothing */);
- 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)
- < (conf->max_nr_stripes *3/4)
- || !conf->inactive_blocked),
- conf->device_lock,
- unplug_slaves(conf->mddev);
- );
- conf->inactive_blocked = 0;
- } else
- init_stripe(sh, sector, pd_idx);
- } else {
- if (atomic_read(&sh->count)) {
- BUG_ON(!list_empty(&sh->lru));
- } else {
- if (!test_bit(STRIPE_HANDLE, &sh->state))
- atomic_inc(&conf->active_stripes);
- BUG_ON(list_empty(&sh->lru));
- list_del_init(&sh->lru);
- }
- }
- } while (sh == NULL);
-
- if (sh)
- atomic_inc(&sh->count);
-
- spin_unlock_irq(&conf->device_lock);
- return sh;
-}
-
-static int grow_one_stripe(raid6_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;
- }
- /* 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(raid6_conf_t *conf, int num)
-{
- kmem_cache_t *sc;
- int devs = conf->raid_disks;
-
- sprintf(conf->cache_name[0], "raid6/%s", mdname(conf->mddev));
-
- sc = kmem_cache_create(conf->cache_name[0],
- sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev),
- 0, 0, NULL, NULL);
- if (!sc)
- return 1;
- conf->slab_cache = sc;
- while (num--)
- if (!grow_one_stripe(conf))
- return 1;
- return 0;
-}
-
-static int drop_one_stripe(raid6_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->raid_disks);
- kmem_cache_free(conf->slab_cache, sh);
- atomic_dec(&conf->active_stripes);
- return 1;
-}
-
-static void shrink_stripes(raid6_conf_t *conf)
-{
- while (drop_one_stripe(conf))
- ;
-
- if (conf->slab_cache)
- kmem_cache_destroy(conf->slab_cache);
- conf->slab_cache = NULL;
-}
-
-static int raid6_end_read_request(struct bio * bi, unsigned int bytes_done,
- int error)
-{
- struct stripe_head *sh = bi->bi_private;
- raid6_conf_t *conf = sh->raid_conf;
- int disks = conf->raid_disks, i;
- int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
-
- if (bi->bi_size)
- return 1;
-
- for (i=0 ; i<disks; i++)
- if (bi == &sh->dev[i].req)
- break;
-
- PRINTK("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 0;
- }
-
- if (uptodate) {
-#if 0
- struct bio *bio;
- unsigned long flags;
- 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]==bh->b_page)
- set_buffer_uptodate(bh);
- 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
- set_bit(R5_UPTODATE, &sh->dev[i].flags);
-#endif
- if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
- printk(KERN_INFO "raid6: read error corrected!!\n");
- 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 {
- int retry = 0;
- clear_bit(R5_UPTODATE, &sh->dev[i].flags);
- atomic_inc(&conf->disks[i].rdev->read_errors);
- if (conf->mddev->degraded)
- printk(KERN_WARNING "raid6: read error not correctable.\n");
- else if (test_bit(R5_ReWrite, &sh->dev[i].flags))
- /* Oh, no!!! */
- printk(KERN_WARNING "raid6: read error NOT corrected!!\n");
- else if (atomic_read(&conf->disks[i].rdev->read_errors)
- > conf->max_nr_stripes)
- printk(KERN_WARNING
- "raid6: Too many read errors, failing device.\n");
- 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, conf->disks[i].rdev);
- }
- }
- rdev_dec_pending(conf->disks[i].rdev, conf->mddev);
-#if 0
- /* must restore b_page before unlocking buffer... */
- if (sh->bh_page[i] != bh->b_page) {
- bh->b_page = sh->bh_page[i];
- bh->b_data = page_address(bh->b_page);
- clear_buffer_uptodate(bh);
- }
-#endif
- clear_bit(R5_LOCKED, &sh->dev[i].flags);
- set_bit(STRIPE_HANDLE, &sh->state);
- release_stripe(sh);
- return 0;
-}
-
-static int raid6_end_write_request (struct bio *bi, unsigned int bytes_done,
- int error)
-{
- struct stripe_head *sh = bi->bi_private;
- raid6_conf_t *conf = sh->raid_conf;
- int disks = conf->raid_disks, i;
- unsigned long flags;
- int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
-
- if (bi->bi_size)
- return 1;
-
- for (i=0 ; i<disks; i++)
- if (bi == &sh->dev[i].req)
- break;
-
- PRINTK("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 0;
- }
-
- spin_lock_irqsave(&conf->device_lock, flags);
- 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(conf, sh);
- spin_unlock_irqrestore(&conf->device_lock, flags);
- return 0;
-}
-
-
-static sector_t compute_blocknr(struct stripe_head *sh, int i);
-
-static void raid6_build_block (struct stripe_head *sh, int i)
-{
- struct r5dev *dev = &sh->dev[i];
- int pd_idx = sh->pd_idx;
- int qd_idx = raid6_next_disk(pd_idx, sh->raid_conf->raid_disks);
-
- 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;
- if (i != pd_idx && i != qd_idx)
- dev->sector = compute_blocknr(sh, i);
-}
-
-static void error(mddev_t *mddev, mdk_rdev_t *rdev)
-{
- char b[BDEVNAME_SIZE];
- raid6_conf_t *conf = (raid6_conf_t *) mddev->private;
- PRINTK("raid6: error called\n");
-
- if (!test_bit(Faulty, &rdev->flags)) {
- mddev->sb_dirty = 1;
- if (test_bit(In_sync, &rdev->flags)) {
- conf->working_disks--;
- mddev->degraded++;
- conf->failed_disks++;
- clear_bit(In_sync, &rdev->flags);
- /*
- * if recovery was running, make sure it aborts.
- */
- set_bit(MD_RECOVERY_ERR, &mddev->recovery);
- }
- set_bit(Faulty, &rdev->flags);
- printk (KERN_ALERT
- "raid6: Disk failure on %s, disabling device."
- " Operation continuing on %d devices\n",
- bdevname(rdev->bdev,b), conf->working_disks);
- }
-}
-
-/*
- * Input: a 'big' sector number,
- * Output: index of the data and parity disk, and the sector # in them.
- */
-static sector_t raid6_compute_sector(sector_t r_sector, unsigned int raid_disks,
- unsigned int data_disks, unsigned int * dd_idx,
- unsigned int * pd_idx, raid6_conf_t *conf)
-{
- long stripe;
- unsigned long chunk_number;
- unsigned int chunk_offset;
- sector_t 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_offset = sector_div(r_sector, sectors_per_chunk);
- chunk_number = r_sector;
- if ( r_sector != chunk_number ) {
- printk(KERN_CRIT "raid6: ERROR: r_sector = %llu, chunk_number = %lu\n",
- (unsigned long long)r_sector, (unsigned long)chunk_number);
- BUG();
- }
-
- /*
- * 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.
- */
-
- /**** FIX THIS ****/
- switch (conf->algorithm) {
- case ALGORITHM_LEFT_ASYMMETRIC:
- *pd_idx = raid_disks - 1 - (stripe % raid_disks);
- if (*pd_idx == raid_disks-1)
- (*dd_idx)++; /* Q D D D P */
- else if (*dd_idx >= *pd_idx)
- (*dd_idx) += 2; /* D D P Q D */
- break;
- case ALGORITHM_RIGHT_ASYMMETRIC:
- *pd_idx = stripe % raid_disks;
- if (*pd_idx == raid_disks-1)
- (*dd_idx)++; /* Q D D D P */
- 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);
- *dd_idx = (*pd_idx + 2 + *dd_idx) % raid_disks;
- break;
- case ALGORITHM_RIGHT_SYMMETRIC:
- *pd_idx = stripe % raid_disks;
- *dd_idx = (*pd_idx + 2 + *dd_idx) % raid_disks;
- break;
- default:
- printk (KERN_CRIT "raid6: unsupported algorithm %d\n",
- conf->algorithm);
- }
-
- PRINTK("raid6: chunk_number = %lu, pd_idx = %u, dd_idx = %u\n",
- chunk_number, *pd_idx, *dd_idx);
-
- /*
- * 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)
-{
- raid6_conf_t *conf = sh->raid_conf;
- int raid_disks = conf->raid_disks, data_disks = raid_disks - 2;
- sector_t new_sector = sh->sector, check;
- int sectors_per_chunk = conf->chunk_size >> 9;
- sector_t stripe;
- int chunk_offset;
- int chunk_number, dummy1, dummy2, dd_idx = i;
- sector_t r_sector;
- int i0 = i;
-
- chunk_offset = sector_div(new_sector, sectors_per_chunk);
- stripe = new_sector;
- if ( new_sector != stripe ) {
- printk(KERN_CRIT "raid6: ERROR: new_sector = %llu, stripe = %lu\n",
- (unsigned long long)new_sector, (unsigned long)stripe);
- BUG();
- }
-
- switch (conf->algorithm) {
- case ALGORITHM_LEFT_ASYMMETRIC:
- case ALGORITHM_RIGHT_ASYMMETRIC:
- 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;
- default:
- printk (KERN_CRIT "raid6: unsupported algorithm %d\n",
- conf->algorithm);
- }
-
- PRINTK("raid6: compute_blocknr: pd_idx = %u, i0 = %u, i = %u\n", sh->pd_idx, i0, i);
-
- chunk_number = stripe * data_disks + i;
- r_sector = (sector_t)chunk_number * sectors_per_chunk + chunk_offset;
-
- check = raid6_compute_sector (r_sector, raid_disks, data_disks, &dummy1, &dummy2, conf);
- if (check != sh->sector || dummy1 != dd_idx || dummy2 != sh->pd_idx) {
- printk(KERN_CRIT "raid6: 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_block(count, STRIPE_SIZE, ptr); \
- count = 1; \
- } \
- } while(0)
-
-/* Compute P and Q syndromes */
-static void compute_parity(struct stripe_head *sh, int method)
-{
- raid6_conf_t *conf = sh->raid_conf;
- int i, pd_idx = sh->pd_idx, qd_idx, d0_idx, disks = conf->raid_disks, count;
- struct bio *chosen;
- /**** FIX THIS: This could be very bad if disks is close to 256 ****/
- void *ptrs[disks];
-
- qd_idx = raid6_next_disk(pd_idx, disks);
- d0_idx = raid6_next_disk(qd_idx, disks);
-
- PRINTK("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);
- }
-
-// switch(method) {
-// case RECONSTRUCT_WRITE:
-// case CHECK_PARITY:
-// case UPDATE_PARITY:
- /* Note that unlike RAID-5, the ordering of the disks matters greatly. */
- /* FIX: Is this ordering of drives even remotely optimal? */
- count = 0;
- i = d0_idx;
- do {
- ptrs[count++] = page_address(sh->dev[i].page);
- if (count <= disks-2 && !test_bit(R5_UPTODATE, &sh->dev[i].flags))
- printk("block %d/%d not uptodate on parity calc\n", i,count);
- i = raid6_next_disk(i, disks);
- } while ( i != d0_idx );
-// break;
-// }
-
- raid6_call.gen_syndrome(disks, 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)
-{
- raid6_conf_t *conf = sh->raid_conf;
- int i, count, disks = conf->raid_disks;
- void *ptr[MAX_XOR_BLOCKS], *p;
- int pd_idx = sh->pd_idx;
- int qd_idx = raid6_next_disk(pd_idx, disks);
-
- PRINTK("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_parity(sh, UPDATE_PARITY);
- } else {
- ptr[0] = page_address(sh->dev[dd_idx].page);
- if (!nozero) memset(ptr[0], 0, STRIPE_SIZE);
- count = 1;
- 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 != 1)
- xor_block(count, STRIPE_SIZE, 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)
-{
- raid6_conf_t *conf = sh->raid_conf;
- int i, count, disks = conf->raid_disks;
- int pd_idx = sh->pd_idx;
- int qd_idx = raid6_next_disk(pd_idx, disks);
- int d0_idx = raid6_next_disk(qd_idx, disks);
- int faila, failb;
-
- /* faila and failb are disk numbers relative to d0_idx */
- /* pd_idx become disks-2 and qd_idx become disks-1 */
- faila = (dd_idx1 < d0_idx) ? dd_idx1+(disks-d0_idx) : dd_idx1-d0_idx;
- failb = (dd_idx2 < d0_idx) ? dd_idx2+(disks-d0_idx) : dd_idx2-d0_idx;
-
- BUG_ON(faila == failb);
- if ( failb < faila ) { int tmp = faila; faila = failb; failb = tmp; }
-
- PRINTK("compute_block_2, stripe %llu, idx %d,%d (%d,%d)\n",
- (unsigned long long)sh->sector, dd_idx1, dd_idx2, faila, failb);
-
- if ( failb == disks-1 ) {
- /* Q disk is one of the missing disks */
- if ( faila == disks-2 ) {
- /* Missing P+Q, just recompute */
- compute_parity(sh, UPDATE_PARITY);
- return;
- } else {
- /* We're missing D+Q; recompute D from P */
- compute_block_1(sh, (dd_idx1 == qd_idx) ? dd_idx2 : dd_idx1, 0);
- compute_parity(sh, UPDATE_PARITY); /* Is this necessary? */
- return;
- }
- }
-
- /* We're missing D+P or D+D; build pointer table */
- {
- /**** FIX THIS: This could be very bad if disks is close to 256 ****/
- void *ptrs[disks];
-
- count = 0;
- i = d0_idx;
- do {
- ptrs[count++] = page_address(sh->dev[i].page);
- i = raid6_next_disk(i, disks);
- if (i != dd_idx1 && i != dd_idx2 &&
- !test_bit(R5_UPTODATE, &sh->dev[i].flags))
- printk("compute_2 with missing block %d/%d\n", count, i);
- } while ( i != d0_idx );
-
- if ( failb == disks-2 ) {
- /* We're missing D+P. */
- raid6_datap_recov(disks, STRIPE_SIZE, faila, ptrs);
- } else {
- /* We're missing D+D. */
- raid6_2data_recov(disks, 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);
- }
-}
-
-
-/*
- * 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;
- raid6_conf_t *conf = sh->raid_conf;
- int firstwrite=0;
-
- PRINTK("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);
-
- PRINTK("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) {
- sh->bm_seq = conf->seq_write;
- bitmap_startwrite(conf->mddev->bitmap, sh->sector,
- STRIPE_SECTORS, 0);
- 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 int page_is_zero(struct page *p)
-{
- char *a = page_address(p);
- return ((*(u32*)a) == 0 &&
- memcmp(a, a+4, STRIPE_SIZE-4)==0);
-}
-/*
- * 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, struct page *tmp_page)
-{
- raid6_conf_t *conf = sh->raid_conf;
- int disks = conf->raid_disks;
- struct bio *return_bi= NULL;
- struct bio *bi;
- int i;
- int syncing;
- int locked=0, uptodate=0, to_read=0, to_write=0, failed=0, written=0;
- int non_overwrite = 0;
- int failed_num[2] = {0, 0};
- struct r5dev *dev, *pdev, *qdev;
- int pd_idx = sh->pd_idx;
- int qd_idx = raid6_next_disk(pd_idx, disks);
- int p_failed, q_failed;
-
- PRINTK("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);
-
- 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 */
-
- rcu_read_lock();
- for (i=disks; i--; ) {
- mdk_rdev_t *rdev;
- dev = &sh->dev[i];
- clear_bit(R5_Insync, &dev->flags);
-
- PRINTK("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;
- PRINTK("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 (--rbi->bi_phys_segments == 0) {
- 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)) locked++;
- if (test_bit(R5_UPTODATE, &dev->flags)) uptodate++;
-
-
- if (dev->toread) to_read++;
- if (dev->towrite) {
- to_write++;
- if (!test_bit(R5_OVERWRITE, &dev->flags))
- non_overwrite++;
- }
- if (dev->written) written++;
- rdev = rcu_dereference(conf->disks[i].rdev);
- 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 ( failed < 2 )
- failed_num[failed] = i;
- failed++;
- } else
- set_bit(R5_Insync, &dev->flags);
- }
- rcu_read_unlock();
- PRINTK("locked=%d uptodate=%d to_read=%d"
- " to_write=%d failed=%d failed_num=%d,%d\n",
- locked, uptodate, to_read, to_write, failed,
- failed_num[0], failed_num[1]);
- /* check if the array has lost >2 devices and, if so, some requests might
- * need to be failed
- */
- if (failed > 2 && to_read+to_write+written) {
- for (i=disks; i--; ) {
- 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) { 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 (--bi->bi_phys_segments == 0) {
- 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 (--bi->bi_phys_segments == 0) {
- md_write_end(conf->mddev);
- bi->bi_next = return_bi;
- return_bi = bi;
- }
- bi = bi2;
- }
-
- /* fail any reads if this device is non-operational */
- if (!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) 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 (--bi->bi_phys_segments == 0) {
- 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 (failed > 2 && syncing) {
- md_done_sync(conf->mddev, STRIPE_SECTORS,0);
- clear_bit(STRIPE_SYNCING, &sh->state);
- 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];
- p_failed = (failed >= 1 && failed_num[0] == pd_idx)
- || (failed >= 2 && failed_num[1] == pd_idx);
- qdev = &sh->dev[qd_idx];
- q_failed = (failed >= 1 && failed_num[0] == qd_idx)
- || (failed >= 2 && failed_num[1] == qd_idx);
-
- if ( written &&
- ( p_failed || ((test_bit(R5_Insync, &pdev->flags)
- && !test_bit(R5_LOCKED, &pdev->flags)
- && test_bit(R5_UPTODATE, &pdev->flags))) ) &&
- ( q_failed || ((test_bit(R5_Insync, &qdev->flags)
- && !test_bit(R5_LOCKED, &qdev->flags)
- && test_bit(R5_UPTODATE, &qdev->flags))) ) ) {
- /* 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.
- */
- 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 */
- int bitmap_end = 0;
- struct bio *wbi, *wbi2;
- PRINTK("Return write for stripe %llu disc %d\n",
- (unsigned long long)sh->sector, 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 (--wbi->bi_phys_segments == 0) {
- 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);
- }
- }
- }
-
- /* 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 (to_read || non_overwrite || (to_write && failed) || (syncing && (uptodate < disks))) {
- for (i=disks; i--;) {
- 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)) ||
- syncing ||
- (failed >= 1 && (sh->dev[failed_num[0]].toread || to_write)) ||
- (failed >= 2 && (sh->dev[failed_num[1]].toread || to_write))
- )
- ) {
- /* we would like to get this block, possibly
- * by computing it, but we might not be able to
- */
- if (uptodate == disks-1) {
- PRINTK("Computing stripe %llu block %d\n",
- (unsigned long long)sh->sector, i);
- compute_block_1(sh, i, 0);
- uptodate++;
- } else if ( uptodate == disks-2 && 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);
- PRINTK("Computing stripe %llu blocks %d,%d\n",
- (unsigned long long)sh->sector, i, other);
- compute_block_2(sh, i, other);
- uptodate += 2;
- } else if (test_bit(R5_Insync, &dev->flags)) {
- set_bit(R5_LOCKED, &dev->flags);
- set_bit(R5_Wantread, &dev->flags);
-#if 0
- /* 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_read[i] && !sh->bh_read[i]->b_reqnext &&
- ! syncing && !failed && !to_write) {
- sh->bh_cache[i]->b_page = sh->bh_read[i]->b_page;
- sh->bh_cache[i]->b_data = sh->bh_read[i]->b_data;
- }
-#endif
- locked++;
- PRINTK("Reading block %d (sync=%d)\n",
- i, syncing);
- }
- }
- }
- set_bit(STRIPE_HANDLE, &sh->state);
- }
-
- /* now to consider writing and what else, if anything should be read */
- if (to_write) {
- int rcw=0, must_compute=0;
- for (i=disks ; i--;) {
- 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)
-#if 0
- || sh->bh_page[i] != bh->b_page
-#endif
- ) &&
- !test_bit(R5_UPTODATE, &dev->flags)) {
- if (test_bit(R5_Insync, &dev->flags)) rcw++;
- else {
- PRINTK("raid6: must_compute: disk %d flags=%#lx\n", i, dev->flags);
- must_compute++;
- }
- }
- }
- PRINTK("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--;) {
- dev = &sh->dev[i];
- if (!test_bit(R5_OVERWRITE, &dev->flags)
- && !(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))
- {
- PRINTK("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);
- locked++;
- } else {
- PRINTK("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 (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 ( failed ) {
- case 0: BUG();
- case 1: compute_block_1(sh, failed_num[0], 0); break;
- case 2: compute_block_2(sh, failed_num[0], failed_num[1]); break;
- default: BUG(); /* This request should have been failed? */
- }
- }
-
- PRINTK("Computing parity for stripe %llu\n", (unsigned long long)sh->sector);
- compute_parity(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)) {
- PRINTK("Writing stripe %llu block %d\n",
- (unsigned long long)sh->sector, i);
- locked++;
- set_bit(R5_Wantwrite, &sh->dev[i].flags);
- }
- /* 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);
- }
- }
- }
-
- /* 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)) {
- int update_p = 0, update_q = 0;
- struct r5dev *dev;
-
- set_bit(STRIPE_HANDLE, &sh->state);
-
- BUG_ON(failed>2);
- BUG_ON(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 (failed == 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 (!q_failed && 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_parity(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 (failed == 2) {
- dev = &sh->dev[failed_num[1]];
- locked++;
- set_bit(R5_LOCKED, &dev->flags);
- set_bit(R5_Wantwrite, &dev->flags);
- }
- if (failed >= 1) {
- dev = &sh->dev[failed_num[0]];
- locked++;
- set_bit(R5_LOCKED, &dev->flags);
- set_bit(R5_Wantwrite, &dev->flags);
- }
-
- if (update_p) {
- dev = &sh->dev[pd_idx];
- locked ++;
- set_bit(R5_LOCKED, &dev->flags);
- set_bit(R5_Wantwrite, &dev->flags);
- }
- if (update_q) {
- dev = &sh->dev[qd_idx];
- 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);
- }
- }
-
- if (syncing && 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 (failed <= 2 && ! conf->mddev->ro)
- for (i=0; i<failed;i++) {
- dev = &sh->dev[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);
- }
- }
- }
- spin_unlock(&sh->lock);
-
- while ((bi=return_bi)) {
- int bytes = bi->bi_size;
-
- return_bi = bi->bi_next;
- bi->bi_next = NULL;
- bi->bi_size = 0;
- bi->bi_end_io(bi, bytes, 0);
- }
- 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 = 1;
- else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
- rw = 0;
- else
- continue;
-
- bi = &sh->dev[i].req;
-
- bi->bi_rw = rw;
- if (rw)
- bi->bi_end_io = raid6_end_write_request;
- else
- bi->bi_end_io = raid6_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 (syncing)
- md_sync_acct(rdev->bdev, STRIPE_SECTORS);
-
- bi->bi_bdev = rdev->bdev;
- PRINTK("for %llu schedule op %ld on disc %d\n",
- (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 == 1)
- set_bit(STRIPE_DEGRADED, &sh->state);
- PRINTK("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 void raid6_activate_delayed(raid6_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 activate_bit_delay(raid6_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)
-{
- raid6_conf_t *conf = mddev_to_conf(mddev);
- int i;
-
- rcu_read_lock();
- for (i=0; i<mddev->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)) {
- request_queue_t *r_queue = bdev_get_queue(rdev->bdev);
-
- atomic_inc(&rdev->nr_pending);
- rcu_read_unlock();
-
- if (r_queue->unplug_fn)
- r_queue->unplug_fn(r_queue);
-
- rdev_dec_pending(rdev, mddev);
- rcu_read_lock();
- }
- }
- rcu_read_unlock();
-}
-
-static void raid6_unplug_device(request_queue_t *q)
-{
- mddev_t *mddev = q->queuedata;
- raid6_conf_t *conf = mddev_to_conf(mddev);
- unsigned long flags;
-
- spin_lock_irqsave(&conf->device_lock, flags);
-
- if (blk_remove_plug(q)) {
- conf->seq_flush++;
- raid6_activate_delayed(conf);
- }
- md_wakeup_thread(mddev->thread);
-
- spin_unlock_irqrestore(&conf->device_lock, flags);
-
- unplug_slaves(mddev);
-}
-
-static int raid6_issue_flush(request_queue_t *q, struct gendisk *disk,
- sector_t *error_sector)
-{
- mddev_t *mddev = q->queuedata;
- raid6_conf_t *conf = mddev_to_conf(mddev);
- int i, ret = 0;
-
- rcu_read_lock();
- for (i=0; i<mddev->raid_disks && ret == 0; i++) {
- mdk_rdev_t *rdev = rcu_dereference(conf->disks[i].rdev);
- if (rdev && !test_bit(Faulty, &rdev->flags)) {
- struct block_device *bdev = rdev->bdev;
- request_queue_t *r_queue = bdev_get_queue(bdev);
-
- if (!r_queue->issue_flush_fn)
- ret = -EOPNOTSUPP;
- else {
- atomic_inc(&rdev->nr_pending);
- rcu_read_unlock();
- ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk,
- error_sector);
- rdev_dec_pending(rdev, mddev);
- rcu_read_lock();
- }
- }
- }
- rcu_read_unlock();
- return ret;
-}
-
-static inline void raid6_plug_device(raid6_conf_t *conf)
-{
- spin_lock_irq(&conf->device_lock);
- blk_plug_device(conf->mddev->queue);
- spin_unlock_irq(&conf->device_lock);
-}
-
-static int make_request (request_queue_t *q, struct bio * bi)
-{
- mddev_t *mddev = q->queuedata;
- raid6_conf_t *conf = mddev_to_conf(mddev);
- const unsigned int raid_disks = conf->raid_disks;
- const unsigned int data_disks = raid_disks - 2;
- unsigned int dd_idx, pd_idx;
- sector_t new_sector;
- sector_t logical_sector, last_sector;
- struct stripe_head *sh;
- const int rw = bio_data_dir(bi);
-
- if (unlikely(bio_barrier(bi))) {
- bio_endio(bi, bi->bi_size, -EOPNOTSUPP);
- return 0;
- }
-
- md_write_start(mddev, bi);
-
- disk_stat_inc(mddev->gendisk, ios[rw]);
- disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bi));
-
- 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);
-
- new_sector = raid6_compute_sector(logical_sector,
- raid_disks, data_disks, &dd_idx, &pd_idx, conf);
-
- PRINTK("raid6: make_request, sector %llu logical %llu\n",
- (unsigned long long)new_sector,
- (unsigned long long)logical_sector);
-
- retry:
- prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
- sh = get_active_stripe(conf, new_sector, pd_idx, (bi->bi_rw&RWA_MASK));
- if (sh) {
- if (!add_stripe_bio(sh, bi, dd_idx, (bi->bi_rw&RW_MASK))) {
- /* Add failed due to overlap. Flush everything
- * and wait a while
- */
- raid6_unplug_device(mddev->queue);
- release_stripe(sh);
- schedule();
- goto retry;
- }
- finish_wait(&conf->wait_for_overlap, &w);
- raid6_plug_device(conf);
- handle_stripe(sh, NULL);
- 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);
- if (--bi->bi_phys_segments == 0) {
- int bytes = bi->bi_size;
-
- if (rw == WRITE )
- md_write_end(mddev);
- bi->bi_size = 0;
- bi->bi_end_io(bi, bytes, 0);
- }
- spin_unlock_irq(&conf->device_lock);
- return 0;
-}
-
-/* FIXME go_faster isn't used */
-static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
-{
- raid6_conf_t *conf = (raid6_conf_t *) mddev->private;
- struct stripe_head *sh;
- int sectors_per_chunk = conf->chunk_size >> 9;
- sector_t x;
- unsigned long stripe;
- int chunk_offset;
- int dd_idx, pd_idx;
- sector_t first_sector;
- int raid_disks = conf->raid_disks;
- int data_disks = raid_disks - 2;
- sector_t max_sector = mddev->size << 1;
- 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 (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 there are 2 or more failed drives and we are trying
- * to resync, then assert that we are finished, because there is
- * nothing we can do.
- */
- if (mddev->degraded >= 2 && test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
- sector_t rv = (mddev->size << 1) - 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 */
- }
-
- x = sector_nr;
- chunk_offset = sector_div(x, sectors_per_chunk);
- stripe = x;
- BUG_ON(x != stripe);
-
- first_sector = raid6_compute_sector((sector_t)stripe*data_disks*sectors_per_chunk
- + chunk_offset, raid_disks, data_disks, &dd_idx, &pd_idx, conf);
- sh = get_active_stripe(conf, sector_nr, pd_idx, 1);
- if (sh == NULL) {
- sh = get_active_stripe(conf, sector_nr, pd_idx, 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<mddev->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);
-
- handle_stripe(sh, NULL);
- release_stripe(sh);
-
- return STRIPE_SECTORS;
-}
-
-/*
- * This is our raid6 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 raid6d (mddev_t *mddev)
-{
- struct stripe_head *sh;
- raid6_conf_t *conf = mddev_to_conf(mddev);
- int handled;
-
- PRINTK("+++ raid6d active\n");
-
- md_check_recovery(mddev);
-
- handled = 0;
- spin_lock_irq(&conf->device_lock);
- while (1) {
- struct list_head *first;
-
- if (conf->seq_flush - conf->seq_write > 0) {
- 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);
- }
-
- if (list_empty(&conf->handle_list) &&
- atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD &&
- !blk_queue_plugged(mddev->queue) &&
- !list_empty(&conf->delayed_list))
- raid6_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);
- BUG_ON(atomic_read(&sh->count)!= 1);
- spin_unlock_irq(&conf->device_lock);
-
- handled++;
- handle_stripe(sh, conf->spare_page);
- release_stripe(sh);
-
- spin_lock_irq(&conf->device_lock);
- }
- PRINTK("%d stripes handled\n", handled);
-
- spin_unlock_irq(&conf->device_lock);
-
- unplug_slaves(mddev);
-
- PRINTK("--- raid6d inactive\n");
-}
-
-static ssize_t
-raid6_show_stripe_cache_size(mddev_t *mddev, char *page)
-{
- raid6_conf_t *conf = mddev_to_conf(mddev);
- if (conf)
- return sprintf(page, "%d\n", conf->max_nr_stripes);
- else
- return 0;
-}
-
-static ssize_t
-raid6_store_stripe_cache_size(mddev_t *mddev, const char *page, size_t len)
-{
- raid6_conf_t *conf = mddev_to_conf(mddev);
- char *end;
- int new;
- if (len >= PAGE_SIZE)
- return -EINVAL;
- if (!conf)
- return -ENODEV;
-
- new = simple_strtoul(page, &end, 10);
- if (!*page || (*end && *end != '\n') )
- 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;
- }
- while (new > conf->max_nr_stripes) {
- if (grow_one_stripe(conf))
- conf->max_nr_stripes++;
- else break;
- }
- return len;
-}
-
-static struct md_sysfs_entry
-raid6_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR,
- raid6_show_stripe_cache_size,
- raid6_store_stripe_cache_size);
-
-static ssize_t
-stripe_cache_active_show(mddev_t *mddev, char *page)
-{
- raid6_conf_t *conf = mddev_to_conf(mddev);
- if (conf)
- return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
- else
- return 0;
-}
-
-static struct md_sysfs_entry
-raid6_stripecache_active = __ATTR_RO(stripe_cache_active);
-
-static struct attribute *raid6_attrs[] = {
- &raid6_stripecache_size.attr,
- &raid6_stripecache_active.attr,
- NULL,
-};
-static struct attribute_group raid6_attrs_group = {
- .name = NULL,
- .attrs = raid6_attrs,
-};
-
-static int run(mddev_t *mddev)
-{
- raid6_conf_t *conf;
- int raid_disk, memory;
- mdk_rdev_t *rdev;
- struct disk_info *disk;
- struct list_head *tmp;
-
- if (mddev->level != 6) {
- PRINTK("raid6: %s: raid level not set to 6 (%d)\n", mdname(mddev), mddev->level);
- return -EIO;
- }
-
- mddev->private = kzalloc(sizeof (raid6_conf_t), GFP_KERNEL);
- if ((conf = mddev->private) == NULL)
- goto abort;
- conf->disks = kzalloc(mddev->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;
-
- 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->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);
-
- PRINTK("raid6: run(%s) called.\n", mdname(mddev));
-
- ITERATE_RDEV(mddev,rdev,tmp) {
- raid_disk = rdev->raid_disk;
- if (raid_disk >= mddev->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 "raid6: device %s operational as raid"
- " disk %d\n", bdevname(rdev->bdev,b),
- raid_disk);
- conf->working_disks++;
- }
- }
-
- conf->raid_disks = mddev->raid_disks;
-
- /*
- * 0 for a fully functional array, 1 or 2 for a degraded array.
- */
- mddev->degraded = conf->failed_disks = conf->raid_disks - conf->working_disks;
- conf->mddev = mddev;
- conf->chunk_size = mddev->chunk_size;
- conf->level = mddev->level;
- conf->algorithm = mddev->layout;
- conf->max_nr_stripes = NR_STRIPES;
-
- /* device size must be a multiple of chunk size */
- mddev->size &= ~(mddev->chunk_size/1024 -1);
- mddev->resync_max_sectors = mddev->size << 1;
-
- if (conf->raid_disks < 4) {
- printk(KERN_ERR "raid6: not enough configured devices for %s (%d, minimum 4)\n",
- mdname(mddev), conf->raid_disks);
- goto abort;
- }
- if (!conf->chunk_size || conf->chunk_size % 4) {
- printk(KERN_ERR "raid6: invalid chunk size %d for %s\n",
- conf->chunk_size, mdname(mddev));
- goto abort;
- }
- if (conf->algorithm > ALGORITHM_RIGHT_SYMMETRIC) {
- printk(KERN_ERR
- "raid6: unsupported parity algorithm %d for %s\n",
- conf->algorithm, mdname(mddev));
- goto abort;
- }
- if (mddev->degraded > 2) {
- printk(KERN_ERR "raid6: not enough operational devices for %s"
- " (%d/%d failed)\n",
- mdname(mddev), conf->failed_disks, conf->raid_disks);
- goto abort;
- }
-
- if (mddev->degraded > 0 &&
- mddev->recovery_cp != MaxSector) {
- if (mddev->ok_start_degraded)
- printk(KERN_WARNING "raid6: starting dirty degraded array:%s"
- "- data corruption possible.\n",
- mdname(mddev));
- else {
- printk(KERN_ERR "raid6: cannot start dirty degraded array"
- " for %s\n", mdname(mddev));
- goto abort;
- }
- }
-
- {
- mddev->thread = md_register_thread(raid6d, mddev, "%s_raid6");
- if (!mddev->thread) {
- printk(KERN_ERR
- "raid6: couldn't allocate thread for %s\n",
- mdname(mddev));
- goto abort;
- }
- }
-
- 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
- "raid6: couldn't allocate %dkB for buffers\n", memory);
- shrink_stripes(conf);
- md_unregister_thread(mddev->thread);
- goto abort;
- } else
- printk(KERN_INFO "raid6: allocated %dkB for %s\n",
- memory, mdname(mddev));
-
- if (mddev->degraded == 0)
- printk(KERN_INFO "raid6: 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,
- conf->algorithm);
- else
- printk(KERN_ALERT "raid6: 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, conf->algorithm);
-
- print_raid6_conf(conf);
-
- /* read-ahead size must cover two whole stripes, which is
- * 2 * (n-2) * chunksize where 'n' is the number of raid devices
- */
- {
- int stripe = (mddev->raid_disks-2) *
- (mddev->chunk_size / 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 */
- sysfs_create_group(&mddev->kobj, &raid6_attrs_group);
-
- mddev->array_size = mddev->size * (mddev->raid_disks - 2);
-
- mddev->queue->unplug_fn = raid6_unplug_device;
- mddev->queue->issue_flush_fn = raid6_issue_flush;
- return 0;
-abort:
- if (conf) {
- print_raid6_conf(conf);
- safe_put_page(conf->spare_page);
- kfree(conf->stripe_hashtbl);
- kfree(conf->disks);
- kfree(conf);
- }
- mddev->private = NULL;
- printk(KERN_ALERT "raid6: failed to run raid set %s\n", mdname(mddev));
- return -EIO;
-}
-
-
-
-static int stop (mddev_t *mddev)
-{
- raid6_conf_t *conf = (raid6_conf_t *) mddev->private;
-
- md_unregister_thread(mddev->thread);
- mddev->thread = NULL;
- shrink_stripes(conf);
- kfree(conf->stripe_hashtbl);
- blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
- sysfs_remove_group(&mddev->kobj, &raid6_attrs_group);
- kfree(conf);
- mddev->private = NULL;
- return 0;
-}
-
-#if RAID6_DUMPSTATE
-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->raid_conf->raid_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, raid6_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++) {
- sh = conf->stripe_hashtbl[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)
-{
- raid6_conf_t *conf = (raid6_conf_t *) mddev->private;
- int i;
-
- seq_printf (seq, " level %d, %dk chunk, algorithm %d", mddev->level, mddev->chunk_size >> 10, mddev->layout);
- seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->working_disks);
- 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, "]");
-#if RAID6_DUMPSTATE
- seq_printf (seq, "\n");
- printall(seq, conf);
-#endif
-}
-
-static void print_raid6_conf (raid6_conf_t *conf)
-{
- int i;
- struct disk_info *tmp;
-
- printk("RAID6 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);
-
- 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 raid6_spare_active(mddev_t *mddev)
-{
- int i;
- raid6_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_bit(In_sync, &tmp->rdev->flags)) {
- mddev->degraded--;
- conf->failed_disks--;
- conf->working_disks++;
- set_bit(In_sync, &tmp->rdev->flags);
- }
- }
- print_raid6_conf(conf);
- return 0;
-}
-
-static int raid6_remove_disk(mddev_t *mddev, int number)
-{
- raid6_conf_t *conf = mddev->private;
- int err = 0;
- mdk_rdev_t *rdev;
- struct disk_info *p = conf->disks + number;
-
- print_raid6_conf(conf);
- rdev = p->rdev;
- if (rdev) {
- if (test_bit(In_sync, &rdev->flags) ||
- atomic_read(&rdev->nr_pending)) {
- 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_raid6_conf(conf);
- return err;
-}
-
-static int raid6_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
-{
- raid6_conf_t *conf = mddev->private;
- int found = 0;
- int disk;
- struct disk_info *p;
-
- if (mddev->degraded > 2)
- /* no point adding a device */
- return 0;
- /*
- * find the disk ... but prefer rdev->saved_raid_disk
- * if possible.
- */
- if (rdev->saved_raid_disk >= 0 &&
- conf->disks[rdev->saved_raid_disk].rdev == NULL)
- disk = rdev->saved_raid_disk;
- else
- disk = 0;
- for ( ; disk < mddev->raid_disks; disk++)
- if ((p=conf->disks + disk)->rdev == NULL) {
- clear_bit(In_sync, &rdev->flags);
- rdev->raid_disk = disk;
- found = 1;
- if (rdev->saved_raid_disk != disk)
- conf->fullsync = 1;
- rcu_assign_pointer(p->rdev, rdev);
- break;
- }
- print_raid6_conf(conf);
- return found;
-}
-
-static int raid6_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_size/512 - 1);
- mddev->array_size = (sectors * (mddev->raid_disks-2))>>1;
- set_capacity(mddev->gendisk, mddev->array_size << 1);
- mddev->changed = 1;
- if (sectors/2 > mddev->size && mddev->recovery_cp == MaxSector) {
- mddev->recovery_cp = mddev->size << 1;
- set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
- }
- mddev->size = sectors /2;
- mddev->resync_max_sectors = sectors;
- return 0;
-}
-
-static void raid6_quiesce(mddev_t *mddev, int state)
-{
- raid6_conf_t *conf = mddev_to_conf(mddev);
-
- switch(state) {
- 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,
- 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);
- spin_unlock_irq(&conf->device_lock);
- break;
- }
-}
-
-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 = raid6_add_disk,
- .hot_remove_disk= raid6_remove_disk,
- .spare_active = raid6_spare_active,
- .sync_request = sync_request,
- .resize = raid6_resize,
- .quiesce = raid6_quiesce,
-};
-
-static int __init raid6_init(void)
-{
- int e;
-
- e = raid6_select_algo();
- if ( e )
- return e;
-
- return register_md_personality(&raid6_personality);
-}
-
-static void raid6_exit (void)
-{
- unregister_md_personality(&raid6_personality);
-}
-
-module_init(raid6_init);
-module_exit(raid6_exit);
-MODULE_LICENSE("GPL");
-MODULE_ALIAS("md-personality-8"); /* RAID6 */
-MODULE_ALIAS("md-raid6");
-MODULE_ALIAS("md-level-6");
projects / linux-2.6 / commitdiff