[PATCH] ext4: Use superblock s_raid_stripe_width as stripe size during block allocation.

["Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>]

The stipe size used during block allocation is calculated as below.
a) if we specify a stripe=<value> option using mount time. Use that value.
b) if not use the value specified in super block.
b) If the value specfied at mount time is greater than blocks per group use
the value specified ini the super block.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 fs/ext4/super.c |   10 ++++++++++
 1 files changed, 10 insertions(+), 0 deletions(-)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index db1edc8..10330eb 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -2136,6 +2136,16 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent)
 	sbi->s_rsv_window_head.rsv_alloc_hit = 0;
 	sbi->s_rsv_window_head.rsv_goal_size = 0;
 	ext4_rsv_window_add(sb, &sbi->s_rsv_window_head);
+	/*
+	 * set the stripe size. If we have specified it via mount option, then
+	 * use the mount option value. If the value specified at mount time is
+	 * greater than the blocks per group use the super block value.
+	 * Allocator needs it be less than blocks per group.
+	 */
+	if (!sbi->s_stripe ||
+			sbi->s_stripe >= sbi->s_blocks_per_group) {
+		sbi->s_stripe = le32_to_cpu(es->s_raid_stripe_width);
+	}
 
 	/*
 	 * set up enough so that it can read an inode
-- 
1.5.4.rc2.60.gb2e62-dirty