From: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
Date: Sat, 8 Feb 2014 15:46:35 +0000 (+0800)
Subject: Btrfs: skip readonly root for snapshot-aware defragment
X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=bcbba5e6593281adc234938b42d3c3d3570335db;p=deliverable%2Flinux.git

Btrfs: skip readonly root for snapshot-aware defragment

Btrfs send is assuming readonly root won't change, let's skip readonly root.

Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
---

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 5b8925003090..b88f6221b48b 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2240,6 +2240,11 @@ static noinline int relink_extent_backref(struct btrfs_path *path,
 		return PTR_ERR(root);
 	}
 
+	if (btrfs_root_readonly(root)) {
+		srcu_read_unlock(&fs_info->subvol_srcu, index);
+		return 0;
+	}
+
 	/* step 2: get inode */
 	key.objectid = backref->inum;
 	key.type = BTRFS_INODE_ITEM_KEY;