From: Daniel J Blueman <daniel@quora.org>
Date: Fri, 27 Apr 2012 16:41:46 +0000 (-0400)
Subject: Btrfs: Prevent root_list corruption
X-Git-Tag: accepted/tizen/common/20141203.182822~4703^2~9
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=1daf3540fa77faea2f91d96bcaf07ce48ee827be;p=platform%2Fkernel%2Flinux-arm64.git

Btrfs: Prevent root_list corruption

I was seeing root_list corruption on unmount during fs resize in 3.4-rc4; add
correct locking to address this.

Signed-off-by: Daniel J Blueman <daniel@quora.org>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
---

diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 017281d..5a105a0 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -1279,7 +1279,9 @@ static int __update_reloc_root(struct btrfs_root *root, int del)
 		if (rb_node)
 			backref_tree_panic(rb_node, -EEXIST, node->bytenr);
 	} else {
+		spin_lock(&root->fs_info->trans_lock);
 		list_del_init(&root->root_list);
+		spin_unlock(&root->fs_info->trans_lock);
 		kfree(node);
 	}
 	return 0;