From fd8c09df09e89cbeb2ae34f5e1aaa65e065b8ecc Mon Sep 17 00:00:00 2001
From: yangsheng <yangsheng>
Date: Wed, 30 Sep 2009 04:13:00 +0000
Subject: [PATCH] Branch HEAD b=19990

i=adilger, johann

Add patch come from upstream kernel to handle the bitmap counter overflow.
---
 .../md-avoid-bug_on-when-bmc-overflow.patch        | 64 ++++++++++++++++++++++
 lustre/kernel_patches/series/2.6-rhel5.series      |  1 +
 2 files changed, 65 insertions(+)
 create mode 100644 lustre/kernel_patches/patches/md-avoid-bug_on-when-bmc-overflow.patch

diff --git a/lustre/kernel_patches/patches/md-avoid-bug_on-when-bmc-overflow.patch b/lustre/kernel_patches/patches/md-avoid-bug_on-when-bmc-overflow.patch
new file mode 100644
index 0000000..f64557e
--- /dev/null
+++ b/lustre/kernel_patches/patches/md-avoid-bug_on-when-bmc-overflow.patch
@@ -0,0 +1,64 @@
+diff .prev/drivers/md/bitmap.c ./drivers/md/bitmap.c
+--- .prev/drivers/md/bitmap.c	2007-02-07 13:03:56.000000000 +1100
++++ ./drivers/md/bitmap.c	2007-02-07 21:34:47.000000000 +1100
+@@ -1160,6 +1160,22 @@ int bitmap_startwrite(struct bitmap *bit
+ 			return 0;
+ 		}
+ 
++		if (unlikely((*bmc & COUNTER_MAX) == COUNTER_MAX)) {
++			DEFINE_WAIT(__wait);
++			/* note that it is safe to do the prepare_to_wait
++			 * after the test as long as we do it before dropping
++			 * the spinlock.
++			 */
++			prepare_to_wait(&bitmap->overflow_wait, &__wait,
++					TASK_UNINTERRUPTIBLE);
++			spin_unlock_irq(&bitmap->lock);
++			bitmap->mddev->queue
++				->unplug_fn(bitmap->mddev->queue);
++			schedule();
++			finish_wait(&bitmap->overflow_wait, &__wait);
++			continue;
++		}
++
+ 		switch(*bmc) {
+ 		case 0:
+ 			bitmap_file_set_bit(bitmap, offset);
+@@ -1169,7 +1185,7 @@ int bitmap_startwrite(struct bitmap *bit
+ 		case 1:
+ 			*bmc = 2;
+ 		}
+-		BUG_ON((*bmc & COUNTER_MAX) == COUNTER_MAX);
++
+ 		(*bmc)++;
+ 
+ 		spin_unlock_irq(&bitmap->lock);
+@@ -1207,6 +1223,9 @@ void bitmap_endwrite(struct bitmap *bitm
+ 		if (!success && ! (*bmc & NEEDED_MASK))
+ 			*bmc |= NEEDED_MASK;
+ 
++		if ((*bmc & COUNTER_MAX) == COUNTER_MAX)
++			wake_up(&bitmap->overflow_wait);
++
+ 		(*bmc)--;
+ 		if (*bmc <= 2) {
+ 			set_page_attr(bitmap,
+@@ -1431,6 +1450,7 @@ int bitmap_create(mddev_t *mddev)
+ 	spin_lock_init(&bitmap->lock);
+ 	atomic_set(&bitmap->pending_writes, 0);
+ 	init_waitqueue_head(&bitmap->write_wait);
++	init_waitqueue_head(&bitmap->overflow_wait);
+ 
+ 	bitmap->mddev = mddev;
+ 
+diff .prev/include/linux/raid/bitmap.h ./include/linux/raid/bitmap.h
+--- .prev/include/linux/raid/bitmap.h	2007-02-07 13:03:56.000000000 +1100
++++ ./include/linux/raid/bitmap.h	2007-02-07 20:57:57.000000000 +1100
+@@ -247,6 +247,7 @@ struct bitmap {
+ 
+ 	atomic_t pending_writes; /* pending writes to the bitmap file */
+ 	wait_queue_head_t write_wait;
++	wait_queue_head_t overflow_wait;
+ 
+ };
+ 
diff --git a/lustre/kernel_patches/series/2.6-rhel5.series b/lustre/kernel_patches/series/2.6-rhel5.series
index 071c4d7..c6dccfe 100644
--- a/lustre/kernel_patches/series/2.6-rhel5.series
+++ b/lustre/kernel_patches/series/2.6-rhel5.series
@@ -26,3 +26,4 @@ mpt-fusion-max-sge.patch
 prune-icache-use-trylock-rhel5.patch
 jbd2-jcberr-2.6-rhel5.patch
 jbd2-commit-timer-no-jiffies-rounding.diff
+md-avoid-bug_on-when-bmc-overflow.patch
-- 
1.8.3.1