From 557c2d8d06101b3e3f1135f6ac4113e4c3870154 Mon Sep 17 00:00:00 2001
From: Chris Mason <chris.mason@oracle.com>
Date: Wed, 14 Oct 2009 09:38:28 -0400
Subject: [PATCH] --- yaml --- r: 167592 b: refs/heads/master c:
 444528b3e614f7f2391488d9bca8e0b872db909b h: refs/heads/master v: v3

---
 [refs]                       | 2 +-
 trunk/fs/btrfs/extent-tree.c | 8 ++++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index e805de5bc1a6..207708da2eb1 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 0634857488ec6e28fa22920cd0bee3c2ac07ccfd
+refs/heads/master: 444528b3e614f7f2391488d9bca8e0b872db909b
diff --git a/trunk/fs/btrfs/extent-tree.c b/trunk/fs/btrfs/extent-tree.c
index d4a35283d99e..c56f91639dc1 100644
--- a/trunk/fs/btrfs/extent-tree.c
+++ b/trunk/fs/btrfs/extent-tree.c
@@ -3686,6 +3686,14 @@ static int pin_down_bytes(struct btrfs_trans_handle *trans,
 	if (is_data)
 		goto pinit;
 
+	/*
+	 * discard is sloooow, and so triggering discards on
+	 * individual btree blocks isn't a good plan.  Just
+	 * pin everything in discard mode.
+	 */
+	if (btrfs_test_opt(root, DISCARD))
+		goto pinit;
+
 	buf = btrfs_find_tree_block(root, bytenr, num_bytes);
 	if (!buf)
 		goto pinit;