btrfs: Remove extent_io_ops::clear_bit_hook callback

This is the counterpart to ex-set_bit_hook (now btrfs_set_delalloc_extent),
similar to what was done before remove clear_bit_hook and rename the
function. No functional changes.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/ctree.h

@@ -3152,6 +3152,8 @@ int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
 			     u64 new_dirid);
 void btrfs_set_delalloc_extent(struct inode *inode, struct extent_state *state,
 			       unsigned *bits);
+void btrfs_clear_delalloc_extent(struct inode *inode,
+				 struct extent_state *state, unsigned *bits);
 int btrfs_merge_bio_hook(struct page *page, unsigned long offset,
 			 size_t size, struct bio *bio,
 			 unsigned long bio_flags);

fs/btrfs/extent_io.c

@@ -404,13 +404,6 @@ static void merge_state(struct extent_io_tree *tree,
 	}
 }
 
-static void clear_state_cb(struct extent_io_tree *tree,
-			   struct extent_state *state, unsigned *bits)
-{
-	if (tree->ops && tree->ops->clear_bit_hook)
-		tree->ops->clear_bit_hook(tree->private_data, state, bits);
-}
-
 static void set_state_bits(struct extent_io_tree *tree,
 			   struct extent_state *state, unsigned *bits,
 			   struct extent_changeset *changeset);
@@ -525,7 +518,10 @@ static struct extent_state *clear_state_bit(struct extent_io_tree *tree,
 		WARN_ON(range > tree->dirty_bytes);
 		tree->dirty_bytes -= range;
 	}
-	clear_state_cb(tree, state, bits);
+
+	if (tree->private_data && is_data_inode(tree->private_data))
+		btrfs_clear_delalloc_extent(tree->private_data, state, bits);
+
 	ret = add_extent_changeset(state, bits_to_clear, changeset, 0);
 	BUG_ON(ret < 0);
 	state->state &= ~bits_to_clear;

fs/btrfs/extent_io.h

@@ -106,9 +106,6 @@ struct extent_io_ops {
 	/*
 	 * Optional hooks, called if the pointer is not NULL
 	 */
-	void (*clear_bit_hook)(void *private_data,
-			struct extent_state *state,
-			unsigned *bits);
 	void (*merge_extent_hook)(void *private_data,
 				  struct extent_state *new,
 				  struct extent_state *other);

fs/btrfs/inode.c

@@ -1806,14 +1806,14 @@ void btrfs_set_delalloc_extent(struct inode *inode, struct extent_state *state,
 }
 
 /*
- * extent_io.c clear_bit_hook, see set_bit_hook for why
+ * Once a range is no longer delalloc this function ensures that proper
+ * accounting happens.
  */
-static void btrfs_clear_bit_hook(void *private_data,
-				 struct extent_state *state,
-				 unsigned *bits)
+void btrfs_clear_delalloc_extent(struct inode *vfs_inode,
+				 struct extent_state *state, unsigned *bits)
 {
-	struct btrfs_inode *inode = BTRFS_I((struct inode *)private_data);
-	struct btrfs_fs_info *fs_info = btrfs_sb(inode->vfs_inode.i_sb);
+	struct btrfs_inode *inode = BTRFS_I(vfs_inode);
+	struct btrfs_fs_info *fs_info = btrfs_sb(vfs_inode->i_sb);
 	u64 len = state->end + 1 - state->start;
 	u32 num_extents = count_max_extents(len);
 
@@ -10509,7 +10509,6 @@ static const struct extent_io_ops btrfs_extent_io_ops = {
 	.readpage_io_failed_hook = btrfs_readpage_io_failed_hook,
 
 	/* optional callbacks */
-	.clear_bit_hook = btrfs_clear_bit_hook,
 	.merge_extent_hook = btrfs_merge_extent_hook,
 	.split_extent_hook = btrfs_split_extent_hook,
 };