bcachefs: Kill nodes_intent_locked

Previously, we used two different bit arrays for tracking held btree
node locks. This patch switches to an array of two bit integers, which
will let us track, in a future patch, when we hold a write lock.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

diff --git a/fs/bcachefs/btree_iter.c b/fs/bcachefs/btree_iter.c
index 147250ce3af8071cf86a455c3c79f44bd8235490..1dc243f63b2d1a9ca08c36270c2b26cb12941f37 100644 (file)
--- a/fs/bcachefs/btree_iter.c
+++ b/fs/bcachefs/btree_iter.c
@@ -1519,7 +1519,6 @@ static struct btree_path *btree_path_alloc(struct btree_trans *trans,
        path->ref               = 0;
        path->intent_ref        = 0;
        path->nodes_locked      = 0;
-       path->nodes_intent_locked = 0;
 
        btree_path_list_add(trans, pos, path);
        trans->paths_sorted = false;
@@ -1574,7 +1573,6 @@ struct btree_path *bch2_path_get(struct btree_trans *trans,
                path->level                     = level;
                path->locks_want                = locks_want;
                path->nodes_locked              = 0;
-               path->nodes_intent_locked       = 0;
                for (i = 0; i < ARRAY_SIZE(path->l); i++)
                        path->l[i].b            = ERR_PTR(-BCH_ERR_no_btree_node_init);
 #ifdef CONFIG_BCACHEFS_DEBUG

diff --git a/fs/bcachefs/btree_locking.h b/fs/bcachefs/btree_locking.h
index f00abaaa0ab59a7e7a8975639376374ab157d077..2253a15d61c90e6703dd4406d4c90f5c75ebc6b9 100644 (file)
--- a/fs/bcachefs/btree_locking.h
+++ b/fs/bcachefs/btree_locking.h
@@ -37,14 +37,7 @@ enum btree_node_locked_type {
 static inline int btree_node_locked_type(struct btree_path *path,
                                         unsigned level)
 {
-       /*
-        * We're relying on the fact that if nodes_intent_locked is set
-        * nodes_locked must be set as well, so that we can compute without
-        * branches:
-        */
-       return BTREE_NODE_UNLOCKED +
-               ((path->nodes_locked >> level) & 1) +
-               ((path->nodes_intent_locked >> level) & 1);
+       return BTREE_NODE_UNLOCKED + ((path->nodes_locked >> (level << 1)) & 3);
 }
 
 static inline bool btree_node_intent_locked(struct btree_path *path,
@@ -65,20 +58,15 @@ static inline bool btree_node_locked(struct btree_path *path, unsigned level)
 }
 
 static inline void mark_btree_node_locked_noreset(struct btree_path *path,
-                                         unsigned level,
-                                         enum btree_node_locked_type type)
+                                                 unsigned level,
+                                                 enum btree_node_locked_type type)
 {
        /* relying on this to avoid a branch */
        BUILD_BUG_ON(SIX_LOCK_read   != 0);
        BUILD_BUG_ON(SIX_LOCK_intent != 1);
 
-       path->nodes_locked &= ~(1 << level);
-       path->nodes_intent_locked &= ~(1 << level);
-
-       if (type != BTREE_NODE_UNLOCKED) {
-               path->nodes_locked |= 1 << level;
-               path->nodes_intent_locked |= type << level;
-       }
+       path->nodes_locked &= ~(3U << (level << 1));
+       path->nodes_locked |= (type + 1) << (level << 1);
 }
 
 static inline void mark_btree_node_unlocked(struct btree_path *path,
@@ -162,12 +150,12 @@ static inline void btree_node_unlock(struct btree_trans *trans,
 
 static inline int btree_path_lowest_level_locked(struct btree_path *path)
 {
-       return __ffs(path->nodes_locked);
+       return __ffs(path->nodes_locked) >> 1;
 }
 
 static inline int btree_path_highest_level_locked(struct btree_path *path)
 {
-       return __fls(path->nodes_locked);
+       return __fls(path->nodes_locked) >> 1;
 }
 
 static inline void __bch2_btree_path_unlock(struct btree_trans *trans,

diff --git a/fs/bcachefs/btree_types.h b/fs/bcachefs/btree_types.h
index 73aaa1196fafb1750f2859cc0354c1619c73cb76..ce148c21fd3be7c5b4c0d6b4c2314d048a521c11 100644 (file)
--- a/fs/bcachefs/btree_types.h
+++ b/fs/bcachefs/btree_types.h
@@ -232,9 +232,8 @@ struct btree_path {
         */
        bool                    should_be_locked:1;
        unsigned                level:3,
-                               locks_want:4,
-                               nodes_locked:4,
-                               nodes_intent_locked:4;
+                               locks_want:4;
+       u8                      nodes_locked;
 
        struct btree_path_level {
                struct btree    *b;