Btrfs: use a cached state for extent state operations during delalloc

This changes the btrfs code to find delalloc ranges in the extent state
tree to use the new state caching code from set/test bit.  It reduces
one of the biggest causes of rbtree searches in the writeback path.

test_range_bit is also modified to take the cached state as a starting
point while searching.

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

1 files changed, 1 insertions, 1 deletions

diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index c8ead2b8c4c9..09cd6fa3cc86 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -157,7 +157,7 @@ u64 count_range_bits(struct extent_io_tree *tree,
                      u64 max_bytes, unsigned long bits);
 
 int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
-                   int bits, int filled);
+                   int bits, int filled, struct extent_state *cached_state);
 int clear_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
                       int bits, gfp_t mask);
 int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,