Btrfs: unlock nodes earlier when inserting items in a btree

In ctree.c:setup_items_for_insert(), we can unlock all nodes in our
path before we process the leaf (shift items and data, adjust data
offsets, etc). This allows for better btree concurrency, as we're
often holding a write lock on at least the node at level 1.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 263145b..bd0ae3e 100644 (file)
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -4738,6 +4738,12 @@ void setup_items_for_insert(struct btrfs_root *root, struct btrfs_path *path,
        int slot;
        struct btrfs_map_token token;
 
+       if (path->slots[0] == 0) {
+               btrfs_cpu_key_to_disk(&disk_key, cpu_key);
+               fixup_low_keys(root, path, &disk_key, 1);
+       }
+       btrfs_unlock_up_safe(path, 1);
+
        btrfs_init_map_token(&token);
 
        leaf = path->nodes[0];
@@ -4798,12 +4804,6 @@ void setup_items_for_insert(struct btrfs_root *root, struct btrfs_path *path,
        }
 
        btrfs_set_header_nritems(leaf, nritems + nr);
-
-       if (slot == 0) {
-               btrfs_cpu_key_to_disk(&disk_key, cpu_key);
-               fixup_low_keys(root, path, &disk_key, 1);
-       }
-       btrfs_unlock_up_safe(path, 1);
        btrfs_mark_buffer_dirty(leaf);
 
        if (btrfs_leaf_free_space(root, leaf) < 0) {