bcachefs: Simplify parameters to bch2_btree_update_start()

We don't need to pass the number of nodes required to
bch2_btree_update_start, just whether we're doing a split at @level.
This is prep work for a fix to our usage of six lock's percpu mode,
which is going to require us to count up and allocate interior nodes and
leaf nodes seperately.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

diff --git a/fs/bcachefs/btree_update_interior.c b/fs/bcachefs/btree_update_interior.c
index 7e876a904c10f9e133e11435a2d32375838933d9..523d1146b2e2fae301a19028b33901c20f08dcbd 100644 (file)
--- a/fs/bcachefs/btree_update_interior.c
+++ b/fs/bcachefs/btree_update_interior.c
@@ -934,7 +934,7 @@ static void bch2_btree_update_done(struct btree_update *as)
 
 static struct btree_update *
 bch2_btree_update_start(struct btree_trans *trans, struct btree_path *path,
-                       unsigned level, unsigned nr_nodes, unsigned flags)
+                       unsigned level, bool split, unsigned flags)
 {
        struct bch_fs *c = trans->c;
        struct btree_update *as;
@@ -942,6 +942,8 @@ bch2_btree_update_start(struct btree_trans *trans, struct btree_path *path,
        u64 start_time = local_clock();
        int disk_res_flags = (flags & BTREE_INSERT_NOFAIL)
                ? BCH_DISK_RESERVATION_NOFAIL : 0;
+       unsigned nr_nodes;
+       unsigned update_level = level;
        int journal_flags = 0;
        int ret = 0;
 
@@ -952,11 +954,26 @@ bch2_btree_update_start(struct btree_trans *trans, struct btree_path *path,
 
        closure_init_stack(&cl);
 retry:
+       nr_nodes = 0;
+
+       while (1) {
+               nr_nodes += 1 + split;
+               update_level++;
+
+               if (!btree_path_node(path, update_level))
+                       break;
+
+               /*
+                * XXX: figure out how far we might need to split,
+                * instead of locking/reserving all the way to the root:
+                */
+               split = update_level + 1 < BTREE_MAX_DEPTH;
+       }
+
+       /* Might have to allocate a new root: */
+       if (update_level < BTREE_MAX_DEPTH)
+               nr_nodes += 1;
 
-       /*
-        * XXX: figure out how far we might need to split,
-        * instead of locking/reserving all the way to the root:
-        */
        if (!bch2_btree_path_upgrade(trans, path, U8_MAX)) {
                trace_trans_restart_iter_upgrade(trans->fn, _RET_IP_,
                                                 path->btree_id, &path->pos);
@@ -1559,14 +1576,13 @@ int bch2_btree_split_leaf(struct btree_trans *trans,
                          struct btree_path *path,
                          unsigned flags)
 {
-       struct bch_fs *c = trans->c;
        struct btree *b = path_l(path)->b;
        struct btree_update *as;
        unsigned l;
        int ret = 0;
 
        as = bch2_btree_update_start(trans, path, path->level,
-               btree_update_reserve_required(c, b), flags);
+                                    true, flags);
        if (IS_ERR(as))
                return PTR_ERR(as);
 
@@ -1677,11 +1693,10 @@ int __bch2_foreground_maybe_merge(struct btree_trans *trans,
                goto out;
 
        parent = btree_node_parent(path, b);
-       as = bch2_btree_update_start(trans, path, level,
-                        btree_update_reserve_required(c, parent) + 1,
-                        flags|
+       as = bch2_btree_update_start(trans, path, level, false,
                         BTREE_INSERT_NOFAIL|
-                        BTREE_INSERT_USE_RESERVE);
+                        BTREE_INSERT_USE_RESERVE|
+                        flags);
        ret = PTR_ERR_OR_ZERO(as);
        if (ret)
                goto err;
@@ -1764,10 +1779,7 @@ int bch2_btree_node_rewrite(struct btree_trans *trans,
 
        parent = btree_node_parent(iter->path, b);
        as = bch2_btree_update_start(trans, iter->path, b->c.level,
-               (parent
-                ? btree_update_reserve_required(c, parent)
-                : 0) + 1,
-               flags);
+                                    false, flags);
        ret = PTR_ERR_OR_ZERO(as);
        if (ret) {
                trace_btree_gc_rewrite_node_fail(c, b);