From: Chris Mason <chris.mason@oracle.com>
Date: Tue, 29 Apr 2008 18:12:09 +0000 (-0400)
Subject: Btrfs: Tune stripe selection for raid1 and raid10
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=2fff734fafa742236aecbdcdc8b1ff4d221cbaca;p=linux-beck.git

Btrfs: Tune stripe selection for raid1 and raid10

Signed-off-by: Chris Mason <chris.mason@oracle.com>
---

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 57ab755aca76..6d8dd4438c76 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1509,17 +1509,17 @@ again:
 	if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
 		if (unplug_page || (rw & (1 << BIO_RW)))
 			num_stripes = map->num_stripes;
-		else if (mirror_num) {
+		else if (mirror_num)
 			stripe_index = mirror_num - 1;
-		} else {
-			u64 orig_stripe_nr = stripe_nr;
-			stripe_index = do_div(orig_stripe_nr, num_stripes);
-		}
+		else
+			stripe_index = current->pid % map->num_stripes;
+
 	} else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
 		if (rw & (1 << BIO_RW))
 			num_stripes = map->num_stripes;
 		else if (mirror_num)
 			stripe_index = mirror_num - 1;
+
 	} else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
 		int factor = map->num_stripes / map->sub_stripes;
 
@@ -1530,11 +1530,8 @@ again:
 			num_stripes = map->sub_stripes;
 		else if (mirror_num)
 			stripe_index += mirror_num - 1;
-		else {
-			u64 orig_stripe_nr = stripe_nr;
-			stripe_index += do_div(orig_stripe_nr,
-					       map->sub_stripes);
-		}
+		else
+			stripe_index += current->pid % map->sub_stripes;
 	} else {
 		/*
 		 * after this do_div call, stripe_nr is the number of stripes