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>

5 files changed, 20 insertions, 26 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;
 
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 8e18fb062215..033a0d5d1789 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1303,8 +1303,10 @@ struct btrfs_map_token {
 #define BTRFS_BYTES_TO_BLKS(fs_info, bytes) \
                                 ((bytes) >> (fs_info)->sb->s_blocksize_bits)
 
-static inline void btrfs_init_map_token (struct btrfs_map_token *token)
+static inline void btrfs_init_map_token(struct btrfs_map_token *token,
+                                        struct extent_buffer *eb)
 {
+        token->eb = eb;
         token->kaddr = NULL;
 }
 
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 07f77c7e6b22..e0e940fe01df 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -3890,7 +3890,7 @@ static void fill_inode_item(struct btrfs_trans_handle *trans,
 {
         struct btrfs_map_token token;
 
-        btrfs_init_map_token(&token);
+        btrfs_init_map_token(&token, leaf);
 
         btrfs_set_token_inode_uid(leaf, item, i_uid_read(inode), &token);
         btrfs_set_token_inode_gid(leaf, item, i_gid_read(inode), &token);
diff --git a/fs/btrfs/struct-funcs.c b/fs/btrfs/struct-funcs.c
index 3a29b911d2e2..73f7987143df 100644
--- a/fs/btrfs/struct-funcs.c
+++ b/fs/btrfs/struct-funcs.c
@@ -53,9 +53,9 @@ u##bits btrfs_get_token_##bits(const struct extent_buffer *eb,		\
         u##bits res;                                                    \
                                                                         \
         ASSERT(token);                                                  \
+        ASSERT(token->eb == eb);                                        \
                                                                         \
         if (token->kaddr && token->offset <= offset &&                  \
-            token->eb == eb &&                                          \
            (token->offset + PAGE_SIZE >= offset + size)) {      \
                 kaddr = token->kaddr;                                   \
                 p = kaddr + part_offset - token->offset;                \
@@ -74,7 +74,6 @@ u##bits btrfs_get_token_##bits(const struct extent_buffer *eb,		\
         res = get_unaligned_le##bits(p + off);                          \
         token->kaddr = kaddr;                                           \
         token->offset = map_start;                                      \
-        token->eb = eb;                                                 \
         return res;                                                     \
 }                                                                       \
 u##bits btrfs_get_##bits(const struct extent_buffer *eb,                \
@@ -117,9 +116,9 @@ void btrfs_set_token_##bits(struct extent_buffer *eb,			\
         int size = sizeof(u##bits);                                     \
                                                                         \
         ASSERT(token);                                                  \
+        ASSERT(token->eb == eb);                                        \
                                                                         \
         if (token->kaddr && token->offset <= offset &&                  \
-            token->eb == eb &&                                          \
            (token->offset + PAGE_SIZE >= offset + size)) {      \
                 kaddr = token->kaddr;                                   \
                 p = kaddr + part_offset - token->offset;                \
@@ -139,7 +138,6 @@ void btrfs_set_token_##bits(struct extent_buffer *eb,			\
         put_unaligned_le##bits(val, p + off);                           \
         token->kaddr = kaddr;                                           \
         token->offset = map_start;                                      \
-        token->eb = eb;                                                 \
 }                                                                       \
 void btrfs_set_##bits(struct extent_buffer *eb, void *ptr,              \
                       unsigned long off, u##bits val)                   \
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 7a0e3f8dec5c..77b6797fcac3 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -506,7 +506,7 @@ insert:
                             ino_size != 0) {
                                 struct btrfs_map_token token;
 
-                                btrfs_init_map_token(&token);
+                                btrfs_init_map_token(&token, dst_eb);
                                 btrfs_set_token_inode_size(dst_eb, dst_item,
                                                            ino_size, &token);
                         }
@@ -3842,7 +3842,7 @@ static void fill_inode_item(struct btrfs_trans_handle *trans,
 {
         struct btrfs_map_token token;
 
-        btrfs_init_map_token(&token);
+        btrfs_init_map_token(&token, leaf);
 
         if (log_inode_only) {
                 /* set the generation to zero so the recover code
@@ -4302,8 +4302,6 @@ static int log_one_extent(struct btrfs_trans_handle *trans,
         if (ret)
                 return ret;
 
-        btrfs_init_map_token(&token);
-
         ret = __btrfs_drop_extents(trans, log, &inode->vfs_inode, path, em->start,
                                    em->start + em->len, NULL, 0, 1,
                                    sizeof(*fi), &extent_inserted);
@@ -4321,6 +4319,7 @@ static int log_one_extent(struct btrfs_trans_handle *trans,
                         return ret;
         }
         leaf = path->nodes[0];
+        btrfs_init_map_token(&token, leaf);
         fi = btrfs_item_ptr(leaf, path->slots[0],
                             struct btrfs_file_extent_item);