From: Nikolay Borisov <nborisov@suse.com>
Date: Mon, 25 Mar 2019 14:31:24 +0200
Git-commit: 41e7acd38c1ae82f24f51d302bbdecdb4675b6b2
Patch-mainline: 5.2
References: bsc#1175149
Subject: [PATCH] btrfs: Rename and export clear_btree_io_tree

This function is going to be used to clear out the device extent
allocation information. Give it a more generic name and export it. This
is in preparation to replacing the pending/pinned chunk lists with an
extent tree. No functional changes.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
---
 fs/btrfs/extent_io.c   |   29 +++++++++++++++++++++++++++++
 fs/btrfs/extent_io.h   |    1 +
 fs/btrfs/transaction.c |   37 ++++---------------------------------
 3 files changed, 34 insertions(+), 33 deletions(-)

--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -277,6 +277,35 @@ void extent_io_tree_init(struct extent_i
 	tree->owner = owner;
 }
 
+void extent_io_tree_release(struct extent_io_tree *tree)
+{
+	spin_lock(&tree->lock);
+	/*
+	 * Do a single barrier for the waitqueue_active check here, the state
+	 * of the waitqueue should not change once extent_io_tree_release is
+	 * called.
+	 */
+	smp_mb();
+	while (!RB_EMPTY_ROOT(&tree->state)) {
+		struct rb_node *node;
+		struct extent_state *state;
+
+		node = rb_first(&tree->state);
+		state = rb_entry(node, struct extent_state, rb_node);
+		rb_erase(&state->rb_node, &tree->state);
+		RB_CLEAR_NODE(&state->rb_node);
+		/*
+		 * btree io trees aren't supposed to have tasks waiting for
+		 * changes in the flags of extent states ever.
+		 */
+		ASSERT(!waitqueue_active(&state->wq));
+		free_extent_state(state);
+
+		cond_resched_lock(&tree->lock);
+	}
+	spin_unlock(&tree->lock);
+}
+
 static struct extent_state *alloc_extent_state(gfp_t mask)
 {
 	struct extent_state *state;
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -278,6 +278,7 @@ typedef struct extent_map *(get_extent_t
 
 void extent_io_tree_init(struct extent_io_tree *tree,
 			 struct address_space *mapping, unsigned int owner);
+void extent_io_tree_release(struct extent_io_tree *tree);
 int try_release_extent_mapping(struct extent_map_tree *map,
 			       struct extent_io_tree *tree, struct page *page,
 			       gfp_t mask);
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -97,35 +97,6 @@ void btrfs_put_transaction(struct btrfs_
 	}
 }
 
-static void clear_btree_io_tree(struct extent_io_tree *tree)
-{
-	spin_lock(&tree->lock);
-	/*
-	 * Do a single barrier for the waitqueue_active check here, the state
-	 * of the waitqueue should not change once clear_btree_io_tree is
-	 * called.
-	 */
-	smp_mb();
-	while (!RB_EMPTY_ROOT(&tree->state)) {
-		struct rb_node *node;
-		struct extent_state *state;
-
-		node = rb_first(&tree->state);
-		state = rb_entry(node, struct extent_state, rb_node);
-		rb_erase(&state->rb_node, &tree->state);
-		RB_CLEAR_NODE(&state->rb_node);
-		/*
-		 * btree io trees aren't supposed to have tasks waiting for
-		 * changes in the flags of extent states ever.
-		 */
-		ASSERT(!waitqueue_active(&state->wq));
-		free_extent_state(state);
-
-		cond_resched_lock(&tree->lock);
-	}
-	spin_unlock(&tree->lock);
-}
-
 static noinline void switch_commit_roots(struct btrfs_transaction *trans,
 					 struct btrfs_fs_info *fs_info)
 {
@@ -139,7 +110,7 @@ static noinline void switch_commit_roots
 		root->commit_root = btrfs_root_node(root);
 		if (is_fstree(root->objectid))
 			btrfs_unpin_free_ino(root);
-		clear_btree_io_tree(&root->dirty_log_pages);
+		extent_io_tree_release(&root->dirty_log_pages);
 		btrfs_qgroup_clean_swapped_blocks(root);
 	}
 
@@ -952,7 +923,7 @@ int btrfs_write_marked_extents(struct bt
 		 * superblock that points to btree nodes/leafs for which
 		 * writeback hasn't finished yet (and without errors).
 		 * We cleanup any entries left in the io tree when committing
-		 * the transaction (through clear_btree_io_tree()).
+		 * the transaction (through extent_io_tree_release()).
 		 */
 		if (err == -ENOMEM) {
 			err = 0;
@@ -997,7 +968,7 @@ static int __btrfs_wait_marked_extents(s
 		 * left in the io tree. For a log commit, we don't remove them
 		 * after committing the log because the tree can be accessed
 		 * concurrently - we do it only at transaction commit time when
-		 * it's safe to do it (through clear_btree_io_tree()).
+		 * it's safe to do it (through extent_io_tree_release()).
 		 */
 		err = clear_extent_bit(dirty_pages, start, end,
 				       EXTENT_NEED_WAIT,
@@ -1076,7 +1047,7 @@ static int btrfs_write_and_wait_transact
 	blk_finish_plug(&plug);
 	ret2 = btrfs_wait_extents(fs_info, dirty_pages);
 
-	clear_btree_io_tree(&trans->transaction->dirty_pages);
+	extent_io_tree_release(&trans->transaction->dirty_pages);
 
 	if (ret)
 		return ret;