bcachefs: Don't start promotes from bch2_rbio_free()

we don't want to block completion of the read - starting a promote calls
into the write path, which will block.

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

diff --git a/fs/bcachefs/io_read.c b/fs/bcachefs/io_read.c
index bdb554f6db8c6c7445cc73a1b519f3d67fe91fc3..15494aba4547b1981317046df0e77bc2f42d3656 100644 (file)
--- a/fs/bcachefs/io_read.c
+++ b/fs/bcachefs/io_read.c
@@ -80,6 +80,7 @@ struct promote_op {
        struct rhash_head       hash;
        struct bpos             pos;
 
+       struct work_struct      work;
        struct data_update      write;
        struct bio_vec          bi_inline_vecs[]; /* must be last */
 };
@@ -149,13 +150,21 @@ static void promote_done(struct bch_write_op *wop)
        promote_free(&op->write.rbio);
 }
 
+static void promote_start_work(struct work_struct *work)
+{
+       struct promote_op *op = container_of(work, struct promote_op, work);
+
+       bch2_data_update_read_done(&op->write);
+}
+
 static noinline void promote_start(struct bch_read_bio *rbio)
 {
        struct promote_op *op = container_of(rbio, struct promote_op, write.rbio);
 
        trace_and_count(op->write.op.c, read_promote, &rbio->bio);
 
-       bch2_data_update_read_done(&op->write);
+       INIT_WORK(&op->work, promote_start_work);
+       queue_work(rbio->c->write_ref_wq, &op->work);
 }
 
 static struct bch_read_bio *__promote_alloc(struct btree_trans *trans,