Btrfs: Simplify the logic in alloc_extent_buffer() for existing extent buffer case

alloc_extent_buffer() uses radix_tree_lookup() when radix_tree_insert()
fails with EEXIST. That part of the code is very similar to the code in
find_extent_buffer(). This patch replaces radix_tree_lookup() and
surrounding code in alloc_extent_buffer() with find_extent_buffer().

Note that radix_tree_lookup() does not need to be protected by
tree->buffer_lock. It is protected by eb->refs.

While at it, this patch
  - changes the other usage of radix_tree_lookup() in alloc_extent_buffer()
    with find_extent_buffer() to reduce redundancy.
  - removes the unused argument 'len' to find_extent_buffer().

Signed-Off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Reviewed-by: Zach Brown <zab@redhat.com>

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index f98602eac808..19620c58f096 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -271,7 +271,7 @@ struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
 struct extent_buffer *alloc_dummy_extent_buffer(u64 start, unsigned long len);
 struct extent_buffer *btrfs_clone_extent_buffer(struct extent_buffer *src);
 struct extent_buffer *find_extent_buffer(struct extent_io_tree *tree,
-					 u64 start, unsigned long len);
+					 u64 start);
 void free_extent_buffer(struct extent_buffer *eb);
 void free_extent_buffer_stale(struct extent_buffer *eb);
 #define WAIT_NONE	0