/usr/src/kernel-patches/lustre/patches/md-avoid-bug_on-when-bmc-overflow.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 | 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;
};
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