/usr/src/kernel-patches/lustre/patches/raid6-serialize-ovelapping-reqs.patch is in linux-patch-lustre 1.8.5+dfsg-3ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 | diff -pur linux-2.6.9.orig/drivers/md/raid6main.c linux-2.6.9/drivers/md/raid6main.c
--- linux-2.6.9.orig/drivers/md/raid6main.c 2008-01-10 13:55:37.000000000 +0800
+++ linux-2.6.9/drivers/md/raid6main.c 2008-01-10 13:55:56.000000000 +0800
@@ -749,6 +749,10 @@ static void compute_parity(struct stripe
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;
}
@@ -907,7 +911,7 @@ static void compute_block_2(struct strip
* toread/towrite point to the first in a chain.
* The bi_next chain must be in order.
*/
-static void add_stripe_bio (struct stripe_head *sh, struct bio *bi, int dd_idx, int forwrite)
+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;
@@ -924,10 +928,13 @@ static void add_stripe_bio (struct strip
else
bip = &sh->dev[dd_idx].toread;
while (*bip && (*bip)->bi_sector < bi->bi_sector) {
- BUG_ON((*bip)->bi_sector + ((*bip)->bi_size >> 9) > bi->bi_sector);
+ if((*bip)->bi_sector + ((*bip)->bi_size >> 9) > bi->bi_sector)
+ goto overlap;
bip = & (*bip)->bi_next;
}
-/* FIXME do I need to worry about overlapping bion */
+ if (*bip && (*bip)->bi_sector < bi->bi_sector + ((bi->bi_size)>>9))
+ goto overlap;
+
if (*bip && bi->bi_next && (*bip) != bi->bi_next)
BUG();
if (*bip)
@@ -954,6 +961,14 @@ static void add_stripe_bio (struct strip
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;
}
/*
@@ -1038,6 +1053,9 @@ static void handle_stripe(struct stripe_
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);
@@ -1087,6 +1105,9 @@ static void handle_stripe(struct stripe_
sh->dev[i].towrite = NULL;
if (bi) to_write--;
+ 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);
@@ -1115,6 +1136,8 @@ static void handle_stripe(struct stripe_
if (!test_bit(R5_Insync, &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);
@@ -1648,6 +1671,8 @@ static int make_request (request_queue_t
sh = NULL;
/* iterrate through all pages in the stripe */
for (j = 0; j < data_disks && sectors > 0; j++) {
+ DEFINE_WAIT(w);
+
if (r_sector + STRIPE_SECTORS <= bi->bi_sector ||
r_sector >= last_sector) {
r_sector += sectors_per_chunk;
@@ -1656,6 +1681,9 @@ static int make_request (request_queue_t
new_sector = raid6_compute_sector(r_sector, raid_disks,
data_disks, &dd_idx,
&pd_idx, conf);
+
+retry:
+ prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
if (sh == NULL) {
/* first, try to get stripe w/o blocking
* if we can't, then it's time to submit
@@ -1668,10 +1696,18 @@ static int make_request (request_queue_t
}
}
if (sh) {
- add_stripe_bio(sh, bi, dd_idx, (bi->bi_rw&RW_MASK));
+ if(!add_stripe_bio(sh, bi, dd_idx, (bi->bi_rw&RW_MASK))) {
+ /* Failed to be added due to overlapped. */
+ raid6_unplug_device(mddev->queue);
+ release_stripe(sh);
+ schedule();
+ goto retry;
+ }
+ finish_wait(&conf->wait_for_overlap, &w);
} else {
/* cannot get stripe for read-ahead, just give-up */
clear_bit(BIO_UPTODATE, &bi->bi_flags);
+ finish_wait(&conf->wait_for_overlap, &w);
sectors = 0;
break;
}
@@ -1847,6 +1883,7 @@ static int run (mddev_t *mddev)
conf->device_lock = SPIN_LOCK_UNLOCKED;
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->inactive_list);
diff -pur linux-2.6.9.orig/include/linux/raid/raid5.h linux-2.6.9/include/linux/raid/raid5.h
--- linux-2.6.9.orig/include/linux/raid/raid5.h 2008-01-10 13:46:05.000000000 +0800
+++ linux-2.6.9/include/linux/raid/raid5.h 2008-01-10 13:55:56.000000000 +0800
@@ -154,6 +154,8 @@ struct stripe_head {
#define R5_Wantwrite 5
#define R5_Syncio 6 /* this io need to be accounted as resync io */
#define R5_Direct 7 /* use page from passed bio to avoid memcpy */
+#define R5_Overlap 8 /* There is a pending overlapping request
+ * on this block */
/*
* Write method
@@ -221,6 +223,7 @@ struct raid5_private_data {
atomic_t active_stripes;
struct list_head inactive_list;
wait_queue_head_t wait_for_stripe;
+ wait_queue_head_t wait_for_overlap;
int inactive_blocked; /* release of inactive stripes blocked,
* waiting for 25% to be free
*/
|