1 files changed, 7 insertions, 6 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 29a2475b9b14..16d335b342a2 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1053,7 +1053,6 @@ static int __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
         INIT_LIST_HEAD(&root->dirty_list);
         INIT_LIST_HEAD(&root->orphan_list);
         INIT_LIST_HEAD(&root->root_list);
-        spin_lock_init(&root->node_lock);
         spin_lock_init(&root->orphan_lock);
         spin_lock_init(&root->inode_lock);
         spin_lock_init(&root->accounting_lock);
@@ -1363,7 +1362,8 @@ static int btrfs_congested_fn(void *congested_data, int bdi_bits)
         struct btrfs_device *device;
         struct backing_dev_info *bdi;
 
-        list_for_each_entry(device, &info->fs_devices->devices, dev_list) {
+        rcu_read_lock();
+        list_for_each_entry_rcu(device, &info->fs_devices->devices, dev_list) {
                 if (!device->bdev)
                         continue;
                 bdi = blk_get_backing_dev_info(device->bdev);
@@ -1372,6 +1372,7 @@ static int btrfs_congested_fn(void *congested_data, int bdi_bits)
                         break;
                 }
         }
+        rcu_read_unlock();
         return ret;
 }
 
@@ -2305,9 +2306,9 @@ int write_all_supers(struct btrfs_root *root, int max_mirrors)
         sb = &root->fs_info->super_for_commit;
         dev_item = &sb->dev_item;
 
-        mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
+        rcu_read_lock();
         head = &root->fs_info->fs_devices->devices;
-        list_for_each_entry(dev, head, dev_list) {
+        list_for_each_entry_rcu(dev, head, dev_list) {
                 if (!dev->bdev) {
                         total_errors++;
                         continue;
@@ -2340,7 +2341,7 @@ int write_all_supers(struct btrfs_root *root, int max_mirrors)
         }
 
         total_errors = 0;
-        list_for_each_entry(dev, head, dev_list) {
+        list_for_each_entry_rcu(dev, head, dev_list) {
                 if (!dev->bdev)
                         continue;
                 if (!dev->in_fs_metadata || !dev->writeable)
@@ -2350,7 +2351,7 @@ int write_all_supers(struct btrfs_root *root, int max_mirrors)
                 if (ret)
                         total_errors++;
         }
-        mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
+        rcu_read_unlock();
         if (total_errors > max_errors) {
                 printk(KERN_ERR "btrfs: %d errors while writing supers\n",
                        total_errors);