bcachefs: btree_trans->write_locked

As prep work for the next patch to fix a key cache reclaim issue, we
need to start tracking whether we're currently holding write locks - so
that we can release and retake the before calling into memory reclaim.

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

diff --git a/fs/bcachefs/btree_trans_commit.c b/fs/bcachefs/btree_trans_commit.c
index decad7b..02491f7 100644 (file)
--- a/fs/bcachefs/btree_trans_commit.c
+++ b/fs/bcachefs/btree_trans_commit.c
@@ -78,6 +78,53 @@ inline void bch2_btree_node_prep_for_write(struct btree_trans *trans,
                bch2_btree_init_next(trans, b);
 }
 
+static noinline int trans_lock_write_fail(struct btree_trans *trans, struct btree_insert_entry *i)
+{
+       while (--i >= trans->updates) {
+               if (same_leaf_as_prev(trans, i))
+                       continue;
+
+               bch2_btree_node_unlock_write(trans, i->path, insert_l(i)->b);
+       }
+
+       trace_and_count(trans->c, trans_restart_would_deadlock_write, trans);
+       return btree_trans_restart(trans, BCH_ERR_transaction_restart_would_deadlock_write);
+}
+
+static inline int bch2_trans_lock_write(struct btree_trans *trans)
+{
+       struct btree_insert_entry *i;
+
+       EBUG_ON(trans->write_locked);
+
+       trans_for_each_update(trans, i) {
+               if (same_leaf_as_prev(trans, i))
+                       continue;
+
+               if (bch2_btree_node_lock_write(trans, i->path, &insert_l(i)->b->c))
+                       return trans_lock_write_fail(trans, i);
+
+               if (!i->cached)
+                       bch2_btree_node_prep_for_write(trans, i->path, insert_l(i)->b);
+       }
+
+       trans->write_locked = true;
+       return 0;
+}
+
+static inline void bch2_trans_unlock_write(struct btree_trans *trans)
+{
+       if (likely(trans->write_locked)) {
+               struct btree_insert_entry *i;
+
+               trans_for_each_update(trans, i)
+                       if (!same_leaf_as_prev(trans, i))
+                               bch2_btree_node_unlock_write_inlined(trans, i->path,
+                                                                    insert_l(i)->b);
+               trans->write_locked = false;
+       }
+}
+
 /* Inserting into a given leaf node (last stage of insert): */
 
 /* Handle overwrites and do insert, for non extents: */
@@ -732,37 +779,6 @@ revert_fs_usage:
        return ret;
 }
 
-static noinline int trans_lock_write_fail(struct btree_trans *trans, struct btree_insert_entry *i)
-{
-       while (--i >= trans->updates) {
-               if (same_leaf_as_prev(trans, i))
-                       continue;
-
-               bch2_btree_node_unlock_write(trans, i->path, insert_l(i)->b);
-       }
-
-       trace_and_count(trans->c, trans_restart_would_deadlock_write, trans);
-       return btree_trans_restart(trans, BCH_ERR_transaction_restart_would_deadlock_write);
-}
-
-static inline int trans_lock_write(struct btree_trans *trans)
-{
-       struct btree_insert_entry *i;
-
-       trans_for_each_update(trans, i) {
-               if (same_leaf_as_prev(trans, i))
-                       continue;
-
-               if (bch2_btree_node_lock_write(trans, i->path, &insert_l(i)->b->c))
-                       return trans_lock_write_fail(trans, i);
-
-               if (!i->cached)
-                       bch2_btree_node_prep_for_write(trans, i->path, insert_l(i)->b);
-       }
-
-       return 0;
-}
-
 static noinline void bch2_drop_overwrites_from_journal(struct btree_trans *trans)
 {
        struct btree_insert_entry *i;
@@ -838,7 +854,7 @@ static inline int do_bch2_trans_commit(struct btree_trans *trans, unsigned flags
        if (unlikely(ret))
                return ret;
 
-       ret = trans_lock_write(trans);
+       ret = bch2_trans_lock_write(trans);
        if (unlikely(ret))
                return ret;
 
@@ -847,10 +863,7 @@ static inline int do_bch2_trans_commit(struct btree_trans *trans, unsigned flags
        if (!ret && unlikely(trans->journal_replay_not_finished))
                bch2_drop_overwrites_from_journal(trans);
 
-       trans_for_each_update(trans, i)
-               if (!same_leaf_as_prev(trans, i))
-                       bch2_btree_node_unlock_write_inlined(trans, i->path,
-                                                       insert_l(i)->b);
+       bch2_trans_unlock_write(trans);
 
        if (!ret && trans->journal_pin)
                bch2_journal_pin_add(&c->journal, trans->journal_res.seq,

diff --git a/fs/bcachefs/btree_types.h b/fs/bcachefs/btree_types.h
index be5d602..f3669fa 100644 (file)
--- a/fs/bcachefs/btree_types.h
+++ b/fs/bcachefs/btree_types.h
@@ -409,6 +409,7 @@ struct btree_trans {
        bool                    journal_transaction_names:1;
        bool                    journal_replay_not_finished:1;
        bool                    notrace_relock_fail:1;
+       bool                    write_locked:1;
        enum bch_errcode        restarted:16;
        u32                     restart_count;
        unsigned long           last_begin_ip;