Btrfs: cache the extent state everywhere we possibly can V2

This patch just goes through and fixes everybody that does

lock_extent()
blah
unlock_extent()

to use

lock_extent_bits()
blah
unlock_extent_cached()

and pass around a extent_state so we only have to do the searches once per
function.  This gives me about a 3 mb/s boots on my random write test.  I have
not converted some things, like the relocation and ioctl's, since they aren't
heavily used and the relocation stuff is in the middle of being re-written.  I
also changed the clear_extent_bit() to only unset the cached state if we are
clearing EXTENT_LOCKED and related stuff, so we can do things like this

lock_extent_bits()
clear delalloc bits
unlock_extent_cached()

without losing our cached state.  I tested this thoroughly and turned on
LEAK_DEBUG to make sure we weren't leaking extent states, everything worked out
fine.

Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index 36de250..bbab481 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -163,6 +163,8 @@
 int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
 		     int bits, struct extent_state **cached, gfp_t mask);
 int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask);
+int unlock_extent_cached(struct extent_io_tree *tree, u64 start, u64 end,
+			 struct extent_state **cached, gfp_t mask);
 int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end,
 		    gfp_t mask);
 int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
@@ -196,7 +198,7 @@
 int clear_extent_ordered_metadata(struct extent_io_tree *tree, u64 start,
 				  u64 end, gfp_t mask);
 int set_extent_delalloc(struct extent_io_tree *tree, u64 start, u64 end,
-		     gfp_t mask);
+			struct extent_state **cached_state, gfp_t mask);
 int set_extent_ordered(struct extent_io_tree *tree, u64 start, u64 end,
 		     gfp_t mask);
 int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
@@ -281,9 +283,11 @@
 int set_extent_buffer_uptodate(struct extent_io_tree *tree,
 			       struct extent_buffer *eb);
 int clear_extent_buffer_uptodate(struct extent_io_tree *tree,
-				struct extent_buffer *eb);
+				struct extent_buffer *eb,
+				struct extent_state **cached_state);
 int extent_buffer_uptodate(struct extent_io_tree *tree,
-			   struct extent_buffer *eb);
+			   struct extent_buffer *eb,
+			   struct extent_state *cached_state);
 int map_extent_buffer(struct extent_buffer *eb, unsigned long offset,
 		      unsigned long min_len, char **token, char **map,
 		      unsigned long *map_start,