From 9bf7933fc3f306bc4ce74ad734f690a71670178a Mon Sep 17 00:00:00 2001
From: Roman Penyaev <rpenyaev@suse.de>
Date: Mon, 25 Mar 2019 20:09:24 +0100
Subject: [PATCH] io_uring: offload write to async worker in case of -EAGAIN
In case of direct write -EAGAIN will be returned if page cache was
previously populated. To avoid immediate completion of a request
with -EAGAIN error write has to be offloaded to the async worker,
like io_read() does.
Signed-off-by: Roman Penyaev <rpenyaev@suse.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
fs/io_uring.c | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 8f48d29abf76c..bbdbd56cf2ac9 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1022,6 +1022,8 @@ static int io_write(struct io_kiocb *req, const struct sqe_submit *s,
ret = rw_verify_area(WRITE, file, &kiocb->ki_pos, iov_count);
if (!ret) {
+ ssize_t ret2;
+
/*
* Open-code file_start_write here to grab freeze protection,
* which will be released by another thread in
@@ -1036,7 +1038,19 @@ static int io_write(struct io_kiocb *req, const struct sqe_submit *s,
SB_FREEZE_WRITE);
}
kiocb->ki_flags |= IOCB_WRITE;
- io_rw_done(kiocb, call_write_iter(file, kiocb, &iter));
+
+ ret2 = call_write_iter(file, kiocb, &iter);
+ if (!force_nonblock || ret2 != -EAGAIN) {
+ io_rw_done(kiocb, ret2);
+ } else {
+ /*
+ * If ->needs_lock is true, we're already in async
+ * context.
+ */
+ if (!s->needs_lock)
+ io_async_list_note(WRITE, req, iov_count);
+ ret = -EAGAIN;
+ }
}
out_free:
kfree(iovec);
--
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