bcachefs: Convert EAGAIN errors to private error codes

More error code cleanup, for better error messages and debugability.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/alloc_foreground.c

@@ -1219,7 +1219,7 @@ int bch2_alloc_sectors_start_trans(struct btree_trans *trans,
 	if (bch2_err_matches(ret, BCH_ERR_open_buckets_empty) ||
 	    bch2_err_matches(ret, BCH_ERR_freelist_empty))
 		return cl
-			? -EAGAIN
+			? -BCH_ERR_bucket_alloc_blocked
 			: -BCH_ERR_ENOSPC_bucket_alloc;
 
 	return ret;

fs/bcachefs/btree_cache.c

@@ -531,7 +531,7 @@ int bch2_btree_cache_cannibalize_lock(struct bch_fs *c, struct closure *cl)
 	}
 
 	trace_and_count(c, btree_cache_cannibalize_lock_fail, c);
-	return -EAGAIN;
+	return -BCH_ERR_btree_cache_cannibalize_lock_blocked;
 
 success:
 	trace_and_count(c, btree_cache_cannibalize_lock, c);
@@ -906,8 +906,6 @@ static struct btree *__bch2_btree_node_get(struct btree_trans *trans, struct btr
  * bch_btree_node_get - find a btree node in the cache and lock it, reading it
  * in from disk if necessary.
  *
- * If IO is necessary and running under generic_make_request, returns -EAGAIN.
- *
  * The btree node will have either a read or a write lock held, depending on
  * the @write parameter.
  */

fs/bcachefs/btree_update_interior.c

@@ -1163,7 +1163,7 @@ bch2_btree_update_start(struct btree_trans *trans, struct btree_path *path,
 
 			bch2_trans_unlock(trans);
 			closure_sync(&cl);
-		} while (ret == -EAGAIN);
+		} while (bch2_err_matches(ret, BCH_ERR_operation_blocked));
 	}
 
 	if (ret) {

fs/bcachefs/btree_update_leaf.c

@@ -332,15 +332,10 @@ bch2_trans_journal_preres_get_cold(struct btree_trans *trans, unsigned u64s,
 static __always_inline int bch2_trans_journal_res_get(struct btree_trans *trans,
 					     unsigned flags)
 {
-	struct bch_fs *c = trans->c;
-	int ret;
-
-	ret = bch2_journal_res_get(&c->journal, &trans->journal_res,
+	return bch2_journal_res_get(&trans->c->journal, &trans->journal_res,
 				    trans->journal_u64s,
 				    flags|
 				    (trans->flags & JOURNAL_WATERMARK_MASK));
-
-	return ret == -EAGAIN ? -BCH_ERR_btree_insert_need_journal_res : ret;
 }
 
 #define JSET_ENTRY_LOG_U64s		4
@@ -864,7 +859,7 @@ static inline int do_bch2_trans_commit(struct btree_trans *trans,
 			&trans->journal_preres, trans->journal_preres_u64s,
 			JOURNAL_RES_GET_NONBLOCK|
 			(trans->flags & JOURNAL_WATERMARK_MASK));
-	if (unlikely(ret == -EAGAIN))
+	if (unlikely(ret == -BCH_ERR_journal_preres_get_blocked))
 		ret = bch2_trans_journal_preres_get_cold(trans,
 						trans->journal_preres_u64s, trace_ip);
 	if (unlikely(ret))
@@ -936,7 +931,7 @@ int bch2_trans_commit_error(struct btree_trans *trans,
 		if (ret)
 			trace_and_count(c, trans_restart_mark_replicas, trans, trace_ip);
 		break;
-	case -BCH_ERR_btree_insert_need_journal_res:
+	case -BCH_ERR_journal_res_get_blocked:
 		bch2_trans_unlock(trans);
 
 		if ((trans->flags & BTREE_INSERT_JOURNAL_RECLAIM) &&

fs/bcachefs/errcode.h

@@ -84,6 +84,11 @@
 	x(EROFS,			erofs_journal_err)			\
 	x(EROFS,			erofs_sb_err)				\
 	x(EROFS,			insufficient_devices)			\
+	x(0,				operation_blocked)			\
+	x(BCH_ERR_operation_blocked,	btree_cache_cannibalize_lock_blocked)	\
+	x(BCH_ERR_operation_blocked,	journal_res_get_blocked)		\
+	x(BCH_ERR_operation_blocked,	journal_preres_get_blocked)		\
+	x(BCH_ERR_operation_blocked,	bucket_alloc_blocked)			\
 	x(BCH_ERR_invalid,		invalid_sb)				\
 	x(BCH_ERR_invalid_sb,		invalid_sb_magic)			\
 	x(BCH_ERR_invalid_sb,		invalid_sb_version)			\

fs/bcachefs/io.c

@@ -1264,7 +1264,7 @@ static void __bch2_write(struct bch_write_op *op)
 					      BCH_WRITE_ONLY_SPECIFIED_DEVS))
 				? NULL : &op->cl, &wp));
 		if (unlikely(ret)) {
-			if (ret == -EAGAIN)
+			if (bch2_err_matches(ret, BCH_ERR_operation_blocked))
 				break;
 
 			goto err;

fs/bcachefs/journal.c

@@ -198,12 +198,6 @@ static bool journal_entry_close(struct journal *j)
 /*
  * should _only_ called from journal_res_get() - when we actually want a
  * journal reservation - journal entry is open means journal is dirty:
- *
- * returns:
- * 0:		success
- * -ENOSPC:	journal currently full, must invoke reclaim
- * -EAGAIN:	journal blocked, must wait
- * -EROFS:	insufficient rw devices or journal error
  */
 static int journal_entry_open(struct journal *j)
 {
@@ -455,7 +449,9 @@ static int __journal_res_get(struct journal *j, struct journal_res *res,
 		}
 	}
 
-	return ret == JOURNAL_ERR_insufficient_devices ? -EROFS : -EAGAIN;
+	return ret == JOURNAL_ERR_insufficient_devices
+		? -EROFS
+		: -BCH_ERR_journal_res_get_blocked;
 }
 
 /*
@@ -474,7 +470,8 @@ int bch2_journal_res_get_slowpath(struct journal *j, struct journal_res *res,
 	int ret;
 
 	closure_wait_event(&j->async_wait,
-		   (ret = __journal_res_get(j, res, flags)) != -EAGAIN ||
+		   (ret = __journal_res_get(j, res, flags)) !=
+		   -BCH_ERR_journal_res_get_blocked||
 		   (flags & JOURNAL_RES_GET_NONBLOCK));
 	return ret;
 }
@@ -792,12 +789,9 @@ static int __bch2_set_nr_journal_buckets(struct bch_dev *ca, unsigned nr,
 		} else {
 			ob[nr_got] = bch2_bucket_alloc(c, ca, RESERVE_none,
 					       false, cl);
-			if (IS_ERR(ob[nr_got])) {
-				ret = cl
-					? -EAGAIN
-					: -BCH_ERR_ENOSPC_bucket_alloc;
+			ret = PTR_ERR_OR_ZERO(ob[nr_got]);
+			if (ret)
 				break;
-			}
 
 			bu[nr_got] = ob[nr_got]->bucket;
 		}
@@ -907,7 +901,7 @@ int bch2_set_nr_journal_buckets(struct bch_fs *c, struct bch_dev *ca,
 
 	closure_init_stack(&cl);
 
-	while (ja->nr != nr && (ret == 0 || ret == -EAGAIN)) {
+	while (ja->nr != nr && (ret == 0 || ret == -BCH_ERR_bucket_alloc_blocked)) {
 		struct disk_reservation disk_res = { 0, 0 };
 
 		closure_sync(&cl);

fs/bcachefs/journal.h

@@ -460,7 +460,7 @@ static inline int bch2_journal_preres_get(struct journal *j,
 		return 0;
 
 	if (flags & JOURNAL_RES_GET_NONBLOCK)
-		return -EAGAIN;
+		return -BCH_ERR_journal_preres_get_blocked;
 
 	return __bch2_journal_preres_get(j, res, new_u64s, flags);
 }