[PATCH 05/13] btrfs: move open coded extent map tree deletion out of inode eviction

[fdmanana@kernel.org]

From: Filipe Manana <fdmanana@suse.com>

Move the loop that removes all the extent maps from the inode's extent
map tree during inode eviction out of inode.c and into extent_map.c, to
btrfs_drop_extent_map_range(). Anything manipulating extent maps or the
extent map tree should be in extent_map.c.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
---
 fs/btrfs/extent_map.c | 27 +++++++++++++++++++++++++++
 fs/btrfs/inode.c      | 15 +--------------
 2 files changed, 28 insertions(+), 14 deletions(-)

diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index 28c5e0243adc..7376c0aa2bca 100644
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -660,6 +660,29 @@ int btrfs_add_extent_mapping(struct btrfs_fs_info *fs_info,
 	return ret;
 }
 
+/*
+ * Drop all extent maps from a tree in the fastest possible way, rescheduling
+ * if needed. This avoids searching the tree, from the root down to the first
+ * extent map, before each deletion.
+ */
+static void drop_all_extent_maps_fast(struct extent_map_tree *tree)
+{
+	write_lock(&tree->lock);
+	while (!RB_EMPTY_ROOT(&tree->map.rb_root)) {
+		struct extent_map *em;
+		struct rb_node *node;
+
+		node = rb_first_cached(&tree->map);
+		em = rb_entry(node, struct extent_map, rb_node);
+		clear_bit(EXTENT_FLAG_PINNED, &em->flags);
+		clear_bit(EXTENT_FLAG_LOGGING, &em->flags);
+		remove_extent_mapping(tree, em);
+		free_extent_map(em);
+		cond_resched_rwlock_write(&tree->lock);
+	}
+	write_unlock(&tree->lock);
+}
+
 /*
  * Drop all extent maps in a given range.
  *
@@ -685,6 +708,10 @@ void btrfs_drop_extent_map_range(struct btrfs_inode *inode, u64 start, u64 end,
 
 	WARN_ON(end < start);
 	if (end == (u64)-1) {
+		if (start == 0 && !skip_pinned) {
+			drop_all_extent_maps_fast(em_tree);
+			return;
+		}
 		len = (u64)-1;
 		testend = false;
 	}
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 32755e2977af..f0cfa9ff5ebd 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -5279,25 +5279,12 @@ static int btrfs_setattr(struct user_namespace *mnt_userns, struct dentry *dentr
 static void evict_inode_truncate_pages(struct inode *inode)
 {
 	struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
-	struct extent_map_tree *map_tree = &BTRFS_I(inode)->extent_tree;
 	struct rb_node *node;
 
 	ASSERT(inode->i_state & I_FREEING);
 	truncate_inode_pages_final(&inode->i_data);
 
-	write_lock(&map_tree->lock);
-	while (!RB_EMPTY_ROOT(&map_tree->map.rb_root)) {
-		struct extent_map *em;
-
-		node = rb_first_cached(&map_tree->map);
-		em = rb_entry(node, struct extent_map, rb_node);
-		clear_bit(EXTENT_FLAG_PINNED, &em->flags);
-		clear_bit(EXTENT_FLAG_LOGGING, &em->flags);
-		remove_extent_mapping(map_tree, em);
-		free_extent_map(em);
-		cond_resched_rwlock_write(&map_tree->lock);
-	}
-	write_unlock(&map_tree->lock);
+	btrfs_drop_extent_map_range(BTRFS_I(inode), 0, (u64)-1, false);
 
 	/*
 	 * Keep looping until we have no more ranges in the io tree.
-- 
2.35.1