btrfs: tie extent buffer and it's token together

Further simplifaction of the get/set helpers is possible when the token
is uniquely tied to an extent buffer. A condition and an assignment can
be avoided.

The initializations are moved closer to the first use when the extent
buffer is valid. There's one exception in __push_leaf_left where the
token is reused.

Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 11 insertions, 16 deletions

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index fbf94e28fba8..88c3b338508d 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -3574,7 +3574,7 @@ static int leaf_space_used(struct extent_buffer *l, int start, int nr)
 
         if (!nr)
                 return 0;
-        btrfs_init_map_token(&token);
+        btrfs_init_map_token(&token, l);
         start_item = btrfs_item_nr(start);
         end_item = btrfs_item_nr(end);
         data_len = btrfs_token_item_offset(l, start_item, &token) +
@@ -3632,8 +3632,6 @@ static noinline int __push_leaf_right(struct btrfs_path *path,
         u32 data_end;
         u32 this_item_size;
 
-        btrfs_init_map_token(&token);
-
         if (empty)
                 nr = 0;
         else
@@ -3706,6 +3704,7 @@ static noinline int __push_leaf_right(struct btrfs_path *path,
                    push_items * sizeof(struct btrfs_item));
 
         /* update the item pointers */
+        btrfs_init_map_token(&token, right);
         right_nritems += push_items;
         btrfs_set_header_nritems(right, right_nritems);
         push_space = BTRFS_LEAF_DATA_SIZE(fs_info);
@@ -3860,8 +3859,6 @@ static noinline int __push_leaf_left(struct btrfs_path *path, int data_size,
         u32 old_left_item_size;
         struct btrfs_map_token token;
 
-        btrfs_init_map_token(&token);
-
         if (empty)
                 nr = min(right_nritems, max_slot);
         else
@@ -3915,6 +3912,7 @@ static noinline int __push_leaf_left(struct btrfs_path *path, int data_size,
         old_left_nritems = btrfs_header_nritems(left);
         BUG_ON(old_left_nritems <= 0);
 
+        btrfs_init_map_token(&token, left);
         old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
         for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
                 u32 ioff;
@@ -3946,6 +3944,8 @@ static noinline int __push_leaf_left(struct btrfs_path *path, int data_size,
                              (btrfs_header_nritems(right) - push_items) *
                              sizeof(struct btrfs_item));
         }
+
+        btrfs_init_map_token(&token, right);
         right_nritems -= push_items;
         btrfs_set_header_nritems(right, right_nritems);
         push_space = BTRFS_LEAF_DATA_SIZE(fs_info);
@@ -4076,8 +4076,6 @@ static noinline void copy_for_split(struct btrfs_trans_handle *trans,
         struct btrfs_disk_key disk_key;
         struct btrfs_map_token token;
 
-        btrfs_init_map_token(&token);
-
         nritems = nritems - mid;
         btrfs_set_header_nritems(right, nritems);
         data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(l);
@@ -4093,6 +4091,7 @@ static noinline void copy_for_split(struct btrfs_trans_handle *trans,
 
         rt_data_off = BTRFS_LEAF_DATA_SIZE(fs_info) - btrfs_item_end_nr(l, mid);
 
+        btrfs_init_map_token(&token, right);
         for (i = 0; i < nritems; i++) {
                 struct btrfs_item *item = btrfs_item_nr(i);
                 u32 ioff;
@@ -4576,8 +4575,6 @@ void btrfs_truncate_item(struct btrfs_path *path, u32 new_size, int from_end)
         int i;
         struct btrfs_map_token token;
 
-        btrfs_init_map_token(&token);
-
         leaf = path->nodes[0];
         slot = path->slots[0];
 
@@ -4599,6 +4596,7 @@ void btrfs_truncate_item(struct btrfs_path *path, u32 new_size, int from_end)
          * item0..itemN ... dataN.offset..dataN.size .. data0.size
          */
         /* first correct the data pointers */
+        btrfs_init_map_token(&token, leaf);
         for (i = slot; i < nritems; i++) {
                 u32 ioff;
                 item = btrfs_item_nr(i);
@@ -4673,8 +4671,6 @@ void btrfs_extend_item(struct btrfs_path *path, u32 data_size)
         int i;
         struct btrfs_map_token token;
 
-        btrfs_init_map_token(&token);
-
         leaf = path->nodes[0];
 
         nritems = btrfs_header_nritems(leaf);
@@ -4699,6 +4695,7 @@ void btrfs_extend_item(struct btrfs_path *path, u32 data_size)
          * item0..itemN ... dataN.offset..dataN.size .. data0.size
          */
         /* first correct the data pointers */
+        btrfs_init_map_token(&token, leaf);
         for (i = slot; i < nritems; i++) {
                 u32 ioff;
                 item = btrfs_item_nr(i);
@@ -4750,8 +4747,6 @@ void setup_items_for_insert(struct btrfs_root *root, struct btrfs_path *path,
         }
         btrfs_unlock_up_safe(path, 1);
 
-        btrfs_init_map_token(&token);
-
         leaf = path->nodes[0];
         slot = path->slots[0];
 
@@ -4765,6 +4760,7 @@ void setup_items_for_insert(struct btrfs_root *root, struct btrfs_path *path,
                 BUG();
         }
 
+        btrfs_init_map_token(&token, leaf);
         if (slot != nritems) {
                 unsigned int old_data = btrfs_item_end_nr(leaf, slot);
 
@@ -4971,9 +4967,6 @@ int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
         int wret;
         int i;
         u32 nritems;
-        struct btrfs_map_token token;
-
-        btrfs_init_map_token(&token);
 
         leaf = path->nodes[0];
         last_off = btrfs_item_offset_nr(leaf, slot + nr - 1);
@@ -4985,12 +4978,14 @@ int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 
         if (slot + nr != nritems) {
                 int data_end = leaf_data_end(leaf);
+                struct btrfs_map_token token;
 
                 memmove_extent_buffer(leaf, BTRFS_LEAF_DATA_OFFSET +
                               data_end + dsize,
                               BTRFS_LEAF_DATA_OFFSET + data_end,
                               last_off - data_end);
 
+                btrfs_init_map_token(&token, leaf);
                 for (i = slot + nr; i < nritems; i++) {
                         u32 ioff;