bcachefs: Fix self deadlock

Before invoking bch2_accounting_mem_mod_locked in
bch2_gc_accounting_done, we already write locked mark_lock,
in bch2_accounting_mem_insert, we lock mark_lock again.

Signed-off-by: Alan Huang <[email protected]>
Signed-off-by: Kent Overstreet <[email protected]>

Author: alanskind

fs/bcachefs/disk_accounting.c

@@ -376,6 +376,19 @@ int bch2_accounting_mem_insert(struct bch_fs *c, struct bkey_s_c_accounting a,
 	return ret;
 }
 
+int bch2_accounting_mem_insert_locked(struct bch_fs *c, struct bkey_s_c_accounting a,
+			       enum bch_accounting_mode mode)
+{
+	struct bch_replicas_padded r;
+
+	if (mode != BCH_ACCOUNTING_read &&
+	    accounting_to_replicas(&r.e, a.k->p) &&
+	    !bch2_replicas_marked_locked(c, &r.e))
+		return -BCH_ERR_btree_insert_need_mark_replicas;
+
+	return __bch2_accounting_mem_insert(c, a);
+}
+
 static bool accounting_mem_entry_is_zero(struct accounting_mem_entry *e)
 {
 	for (unsigned i = 0; i < e->nr_counters; i++)
@@ -583,7 +596,7 @@ int bch2_gc_accounting_done(struct bch_fs *c)
 					accounting_key_init(&k_i.k, &acc_k, src_v, nr);
 					bch2_accounting_mem_mod_locked(trans,
 								bkey_i_to_s_c_accounting(&k_i.k),
-								BCH_ACCOUNTING_normal);
+								BCH_ACCOUNTING_normal, true);
 
 					preempt_disable();
 					struct bch_fs_usage_base *dst = this_cpu_ptr(c->usage);
@@ -612,7 +625,7 @@ static int accounting_read_key(struct btree_trans *trans, struct bkey_s_c k)
 
 	percpu_down_read(&c->mark_lock);
 	int ret = bch2_accounting_mem_mod_locked(trans, bkey_s_c_to_accounting(k),
-						 BCH_ACCOUNTING_read);
+						 BCH_ACCOUNTING_read, false);
 	percpu_up_read(&c->mark_lock);
 	return ret;
 }

fs/bcachefs/disk_accounting.h

@@ -136,6 +136,7 @@ enum bch_accounting_mode {
 };
 
 int bch2_accounting_mem_insert(struct bch_fs *, struct bkey_s_c_accounting, enum bch_accounting_mode);
+int bch2_accounting_mem_insert_locked(struct bch_fs *, struct bkey_s_c_accounting, enum bch_accounting_mode);
 void bch2_accounting_mem_gc(struct bch_fs *);
 
 static inline bool bch2_accounting_is_mem(struct disk_accounting_pos acc)
@@ -150,7 +151,8 @@ static inline bool bch2_accounting_is_mem(struct disk_accounting_pos acc)
  */
 static inline int bch2_accounting_mem_mod_locked(struct btree_trans *trans,
 						 struct bkey_s_c_accounting a,
-						 enum bch_accounting_mode mode)
+						 enum bch_accounting_mode mode,
+						 bool write_locked)
 {
 	struct bch_fs *c = trans->c;
 	struct bch_accounting_mem *acc = &c->accounting;
@@ -189,7 +191,11 @@ static inline int bch2_accounting_mem_mod_locked(struct btree_trans *trans,
 
 	while ((idx = eytzinger0_find(acc->k.data, acc->k.nr, sizeof(acc->k.data[0]),
 				      accounting_pos_cmp, &a.k->p)) >= acc->k.nr) {
-		int ret = bch2_accounting_mem_insert(c, a, mode);
+		int ret = 0;
+		if (unlikely(write_locked))
+			ret = bch2_accounting_mem_insert_locked(c, a, mode);
+		else
+			ret = bch2_accounting_mem_insert(c, a, mode);
 		if (ret)
 			return ret;
 	}
@@ -206,7 +212,7 @@ static inline int bch2_accounting_mem_mod_locked(struct btree_trans *trans,
 static inline int bch2_accounting_mem_add(struct btree_trans *trans, struct bkey_s_c_accounting a, bool gc)
 {
 	percpu_down_read(&trans->c->mark_lock);
-	int ret = bch2_accounting_mem_mod_locked(trans, a, gc ? BCH_ACCOUNTING_gc : BCH_ACCOUNTING_normal);
+	int ret = bch2_accounting_mem_mod_locked(trans, a, gc ? BCH_ACCOUNTING_gc : BCH_ACCOUNTING_normal, false);
 	percpu_up_read(&trans->c->mark_lock);
 	return ret;
 }
@@ -259,7 +265,7 @@ static inline int bch2_accounting_trans_commit_hook(struct btree_trans *trans,
 	EBUG_ON(bversion_zero(a->k.bversion));
 
 	return likely(!(commit_flags & BCH_TRANS_COMMIT_skip_accounting_apply))
-		? bch2_accounting_mem_mod_locked(trans, accounting_i_to_s_c(a), BCH_ACCOUNTING_normal)
+		? bch2_accounting_mem_mod_locked(trans, accounting_i_to_s_c(a), BCH_ACCOUNTING_normal, false)
 		: 0;
 }
 
@@ -271,7 +277,7 @@ static inline void bch2_accounting_trans_commit_revert(struct btree_trans *trans
 		struct bkey_s_accounting a = accounting_i_to_s(a_i);
 
 		bch2_accounting_neg(a);
-		bch2_accounting_mem_mod_locked(trans, a.c, BCH_ACCOUNTING_normal);
+		bch2_accounting_mem_mod_locked(trans, a.c, BCH_ACCOUNTING_normal, false);
 		bch2_accounting_neg(a);
 	}
 }