Btrfs: remove unnecessary ->s_umount in cleaner_kthread()

[linux-2.6-block.git] / fs / btrfs / disk-io.c

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index bc2ea9b53048349911561f765d5976490c8103b7..7a54b8e7d124b855aa69387d28874f1f1a46385f 100644 (file)
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1673,24 +1673,40 @@ static void end_workqueue_fn(struct btrfs_work *work)
        bio_endio(bio, error);
 }
 
+/*
+ * If we remount the fs to be R/O, the cleaner needn't do anything except
+ * sleeping. This function is used to check the status of the fs.
+ */
+static inline int need_cleaner_sleep(struct btrfs_root *root)
+{
+       return root->fs_info->sb->s_flags & MS_RDONLY;
+}
+
 static int cleaner_kthread(void *arg)
 {
        struct btrfs_root *root = arg;
+       int again;
 
        do {
-               int again = 0;
-
-               if (!(root->fs_info->sb->s_flags & MS_RDONLY) &&
-                   down_read_trylock(&root->fs_info->sb->s_umount)) {
-                       if (mutex_trylock(&root->fs_info->cleaner_mutex)) {
-                               btrfs_run_delayed_iputs(root);
-                               again = btrfs_clean_one_deleted_snapshot(root);
-                               mutex_unlock(&root->fs_info->cleaner_mutex);
-                       }
-                       btrfs_run_defrag_inodes(root->fs_info);
-                       up_read(&root->fs_info->sb->s_umount);
-               }
+               again = 0;
 
+               /* Make the cleaner go to sleep early. */
+               if (need_cleaner_sleep(root))
+                       goto sleep;
+
+               if (!mutex_trylock(&root->fs_info->cleaner_mutex))
+                       goto sleep;
+
+               btrfs_run_delayed_iputs(root);
+               again = btrfs_clean_one_deleted_snapshot(root);
+               mutex_unlock(&root->fs_info->cleaner_mutex);
+
+               /*
+                * The defragger has dealt with the R/O remount, needn't
+                * do anything special here.
+                */
+               btrfs_run_defrag_inodes(root->fs_info);
+sleep:
                if (!try_to_freeze() && !again) {
                        set_current_state(TASK_INTERRUPTIBLE);
                        if (!kthread_should_stop())