bcachefs: Kill bch_write_op.index_update_fn

This deletes bch_write_op.index_update_fn: indirect function calls have
gotten considerably more expensive post spectre/meltdown, and we only
have two different index_update_fns - this patch adds a flag to specify
which one to use (normal vs. data move path).
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/io.c

@@ -432,7 +432,7 @@ int bch2_fpunch(struct bch_fs *c, u64 inum, u64 start, u64 end,
 	return ret;
 }
 
-int bch2_write_index_default(struct bch_write_op *op)
+static int bch2_write_index_default(struct bch_write_op *op)
 {
 	struct bch_fs *c = op->c;
 	struct bkey_buf sk;
@@ -577,7 +577,7 @@ static void __bch2_write_index(struct bch_write_op *op)
 	struct bch_extent_ptr *ptr;
 	struct bkey_i *src, *dst = keys->keys, *n, *k;
 	unsigned dev;
-	int ret;
+	int ret = 0;
 
 	for (src = keys->keys; src != keys->top; src = n) {
 		n = bkey_next(src);
@@ -614,7 +614,10 @@ static void __bch2_write_index(struct bch_write_op *op)
 
 	if (!bch2_keylist_empty(keys)) {
 		u64 sectors_start = keylist_sectors(keys);
-		int ret = op->index_update_fn(op);
+
+		ret = !(op->flags & BCH_WRITE_MOVE)
+			? bch2_write_index_default(op)
+			: bch2_migrate_index_update(op);
 
 		BUG_ON(ret == -EINTR);
 		BUG_ON(keylist_sectors(keys) && !ret);
@@ -624,7 +627,7 @@ static void __bch2_write_index(struct bch_write_op *op)
 		if (ret) {
 			bch_err_inum_ratelimited(c, op->pos.inode,
 				"write error %i from btree update", ret);
-			op->error = ret;
+			goto err;
 		}
 	}
 out:

fs/bcachefs/io.h

@@ -29,23 +29,39 @@ void bch2_submit_wbio_replicas(struct bch_write_bio *, struct bch_fs *,
 const char *bch2_blk_status_to_str(blk_status_t);
 
 enum bch_write_flags {
-	BCH_WRITE_ALLOC_NOWAIT		= (1 << 0),
-	BCH_WRITE_CACHED		= (1 << 1),
-	BCH_WRITE_FLUSH			= (1 << 2),
-	BCH_WRITE_DATA_ENCODED		= (1 << 3),
-	BCH_WRITE_PAGES_STABLE		= (1 << 4),
-	BCH_WRITE_PAGES_OWNED		= (1 << 5),
-	BCH_WRITE_ONLY_SPECIFIED_DEVS	= (1 << 6),
-	BCH_WRITE_WROTE_DATA_INLINE	= (1 << 7),
-	BCH_WRITE_FROM_INTERNAL		= (1 << 8),
-	BCH_WRITE_CHECK_ENOSPC		= (1 << 9),
-
-	/* Internal: */
-	BCH_WRITE_JOURNAL_SEQ_PTR	= (1 << 10),
-	BCH_WRITE_SKIP_CLOSURE_PUT	= (1 << 11),
-	BCH_WRITE_DONE			= (1 << 12),
+	__BCH_WRITE_ALLOC_NOWAIT,
+	__BCH_WRITE_CACHED,
+	__BCH_WRITE_FLUSH,
+	__BCH_WRITE_DATA_ENCODED,
+	__BCH_WRITE_PAGES_STABLE,
+	__BCH_WRITE_PAGES_OWNED,
+	__BCH_WRITE_ONLY_SPECIFIED_DEVS,
+	__BCH_WRITE_WROTE_DATA_INLINE,
+	__BCH_WRITE_FROM_INTERNAL,
+	__BCH_WRITE_CHECK_ENOSPC,
+	__BCH_WRITE_MOVE,
+	__BCH_WRITE_JOURNAL_SEQ_PTR,
+	__BCH_WRITE_SKIP_CLOSURE_PUT,
+	__BCH_WRITE_DONE,
 };
 
+#define BCH_WRITE_ALLOC_NOWAIT		(1U << __BCH_WRITE_ALLOC_NOWAIT)
+#define BCH_WRITE_CACHED		(1U << __BCH_WRITE_CACHED)
+#define BCH_WRITE_FLUSH			(1U << __BCH_WRITE_FLUSH)
+#define BCH_WRITE_DATA_ENCODED		(1U << __BCH_WRITE_DATA_ENCODED)
+#define BCH_WRITE_PAGES_STABLE		(1U << __BCH_WRITE_PAGES_STABLE)
+#define BCH_WRITE_PAGES_OWNED		(1U << __BCH_WRITE_PAGES_OWNED)
+#define BCH_WRITE_ONLY_SPECIFIED_DEVS	(1U << __BCH_WRITE_ONLY_SPECIFIED_DEVS)
+#define BCH_WRITE_WROTE_DATA_INLINE	(1U << __BCH_WRITE_WROTE_DATA_INLINE)
+#define BCH_WRITE_FROM_INTERNAL		(1U << __BCH_WRITE_FROM_INTERNAL)
+#define BCH_WRITE_CHECK_ENOSPC		(1U << __BCH_WRITE_CHECK_ENOSPC)
+#define BCH_WRITE_MOVE			(1U << __BCH_WRITE_MOVE)
+
+/* Internal: */
+#define BCH_WRITE_JOURNAL_SEQ_PTR	(1U << __BCH_WRITE_JOURNAL_SEQ_PTR)
+#define BCH_WRITE_SKIP_CLOSURE_PUT	(1U << __BCH_WRITE_SKIP_CLOSURE_PUT)
+#define BCH_WRITE_DONE			(1U << __BCH_WRITE_DONE)
+
 static inline u64 *op_journal_seq(struct bch_write_op *op)
 {
 	return (op->flags & BCH_WRITE_JOURNAL_SEQ_PTR)
@@ -74,8 +90,6 @@ int bch2_fpunch_at(struct btree_trans *, struct btree_iter *,
 		   struct bpos, u64 *, s64 *);
 int bch2_fpunch(struct bch_fs *c, u64, u64, u64, u64 *, s64 *);
 
-int bch2_write_index_default(struct bch_write_op *);
-
 static inline void bch2_write_op_init(struct bch_write_op *op, struct bch_fs *c,
 				      struct bch_io_opts opts)
 {
@@ -101,7 +115,6 @@ static inline void bch2_write_op_init(struct bch_write_op *op, struct bch_fs *c,
 	op->journal_seq		= 0;
 	op->new_i_size		= U64_MAX;
 	op->i_sectors_delta	= 0;
-	op->index_update_fn	= bch2_write_index_default;
 }
 
 void bch2_write(struct closure *);

fs/bcachefs/io_types.h

@@ -146,8 +146,6 @@ struct bch_write_op {
 	u64			new_i_size;
 	s64			i_sectors_delta;
 
-	int			(*index_update_fn)(struct bch_write_op *);
-
 	struct bch_devs_mask	failed;
 
 	struct keylist		insert_keys;

fs/bcachefs/move.c

@@ -52,7 +52,7 @@ struct moving_context {
 	wait_queue_head_t	wait;
 };
 
-static int bch2_migrate_index_update(struct bch_write_op *op)
+int bch2_migrate_index_update(struct bch_write_op *op)
 {
 	struct bch_fs *c = op->c;
 	struct btree_trans trans;
@@ -266,11 +266,11 @@ int bch2_migrate_write_init(struct bch_fs *c, struct migrate_write *m,
 	m->op.flags |= BCH_WRITE_PAGES_STABLE|
 		BCH_WRITE_PAGES_OWNED|
 		BCH_WRITE_DATA_ENCODED|
-		BCH_WRITE_FROM_INTERNAL;
+		BCH_WRITE_FROM_INTERNAL|
+		BCH_WRITE_MOVE;
 
 	m->op.nr_replicas	= data_opts.nr_replicas;
 	m->op.nr_replicas_required = data_opts.nr_replicas;
-	m->op.index_update_fn	= bch2_migrate_index_update;
 
 	switch (data_cmd) {
 	case DATA_ADD_REPLICAS: {

fs/bcachefs/move.h

@@ -41,6 +41,7 @@ struct migrate_write {
 	struct bch_write_op	op;
 };
 
+int bch2_migrate_index_update(struct bch_write_op *);
 void bch2_migrate_read_done(struct migrate_write *, struct bch_read_bio *);
 int bch2_migrate_write_init(struct bch_fs *, struct migrate_write *,
 			    struct write_point_specifier,