btrfs: convert the io_failure_tree to a plain rb_tree

We still have this oddity of stashing the io_failure_record in the
extent state for the io_failure_tree, which is leftover from when we
used to stuff private pointers in extent_io_trees.

However this doesn't make a lot of sense for the io failure records, we
can simply use a normal rb_tree for this.  This will allow us to further
simplify the extent_io_tree code by removing the io_failure_rec pointer
from the extent state.

Convert the io_failure_tree to an rb tree + spinlock in the inode, and
then use our rb tree simple helpers to insert and find failed records.
This greatly cleans up this code and makes it easier to separate out the
extent_io_tree code.

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

1 files changed, 35 insertions, 0 deletions

diff --git a/fs/btrfs/misc.h b/fs/btrfs/misc.h
index 340f995652f2..f9850edfd726 100644
--- a/fs/btrfs/misc.h
+++ b/fs/btrfs/misc.h
@@ -88,6 +88,41 @@ static inline struct rb_node *rb_simple_search(struct rb_root *root, u64 bytenr)
 	return NULL;
 }
 
+/*
+ * Search @root from an entry that starts or comes after @bytenr.
+ *
+ * @root:	the root to search.
+ * @bytenr:	bytenr to search from.
+ *
+ * Return the rb_node that start at or after @bytenr.  If there is no entry at
+ * or after @bytner return NULL.
+ */
+static inline struct rb_node *rb_simple_search_first(struct rb_root *root,
+						     u64 bytenr)
+{
+	struct rb_node *node = root->rb_node, *ret = NULL;
+	struct rb_simple_node *entry, *ret_entry = NULL;
+
+	while (node) {
+		entry = rb_entry(node, struct rb_simple_node, rb_node);
+
+		if (bytenr < entry->bytenr) {
+			if (!ret || entry->bytenr < ret_entry->bytenr) {
+				ret = node;
+				ret_entry = entry;
+			}
+
+			node = node->rb_left;
+		} else if (bytenr > entry->bytenr) {
+			node = node->rb_right;
+		} else {
+			return node;
+		}
+	}
+
+	return ret;
+}
+
 static inline struct rb_node *rb_simple_insert(struct rb_root *root, u64 bytenr,
 					       struct rb_node *node)
 {