Btrfs: add and improve comments

This improves the comments at the top of many functions.  It didn't
dive into the guts of functions because I was trying to
avoid merging problems with the new allocator and back reference work.

extent-tree.c and volumes.c were both skipped, and there is definitely
more work todo in cleaning and commenting the code.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/fs/btrfs/tree-defrag.c b/fs/btrfs/tree-defrag.c
index b3bb5bbad76e..6f57d0889b1e 100644
--- a/fs/btrfs/tree-defrag.c
+++ b/fs/btrfs/tree-defrag.c
@@ -23,6 +23,10 @@
 #include "transaction.h"
 #include "locking.h"
 
+/* defrag all the leaves in a given btree.  If cache_only == 1, don't read things
+ * from disk, otherwise read all the leaves and try to get key order to
+ * better reflect disk order
+ */
 int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,
                         struct btrfs_root *root, int cache_only)
 {