Commit 4e17aaab authored by Stefan Roesch's avatar Stefan Roesch Committed by Jens Axboe
Browse files

io_uring: Add support for async buffered writes 



This enables the async buffered writes for the filesystems that support
async buffered writes in io-uring. Buffered writes are enabled for
blocks that are already in the page cache or can be acquired with noio.

Signed-off-by: default avatarStefan Roesch <shr@fb.com>
Link: https://lore.kernel.org/r/20220616212221.2024518-12-shr@fb.com


[axboe: adapt to 5.20 branch]
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 66fa3ced

io_uring/rw.c

+24 −5
Original line number Diff line number Diff line
@@ -641,7 +641,7 @@ static inline int io_iter_do_read(struct io_rw *rw, struct iov_iter *iter) 
		return -EINVAL;

}



static bool need_read_all(struct io_kiocb *req)

static bool need_complete_io(struct io_kiocb *req)

{

	return req->flags & REQ_F_ISREG ||

		S_ISBLK(file_inode(req->file)->i_mode);
@@ -775,7 +775,7 @@ int io_read(struct io_kiocb *req, unsigned int issue_flags) 
			kfree(iovec);

		return IOU_ISSUE_SKIP_COMPLETE;

	} else if (ret == req->cqe.res || ret <= 0 || !force_nonblock ||

		   (req->flags & REQ_F_NOWAIT) || !need_read_all(req)) {

		   (req->flags & REQ_F_NOWAIT) || !need_complete_io(req)) {

		/* read all, failed, already did sync or don't want to retry */

		goto done;

	}
@@ -870,8 +870,9 @@ int io_write(struct io_kiocb *req, unsigned int issue_flags) 
		if (unlikely(!io_file_supports_nowait(req)))

			goto copy_iov;



		/* file path doesn't support NOWAIT for non-direct_IO */

		if (force_nonblock && !(kiocb->ki_flags & IOCB_DIRECT) &&

		/* File path supports NOWAIT for non-direct_IO only for block devices. */

		if (!(kiocb->ki_flags & IOCB_DIRECT) &&

			!(kiocb->ki_filp->f_mode & FMODE_BUF_WASYNC) &&

			(req->flags & REQ_F_ISREG))

			goto copy_iov;
@@ -928,6 +929,24 @@ int io_write(struct io_kiocb *req, unsigned int issue_flags) 
		/* IOPOLL retry should happen for io-wq threads */

		if (ret2 == -EAGAIN && (req->ctx->flags & IORING_SETUP_IOPOLL))

			goto copy_iov;



		if (ret2 != req->cqe.res && ret2 >= 0 && need_complete_io(req)) {

			struct io_async_rw *rw;



			/* This is a partial write. The file pos has already been

			 * updated, setup the async struct to complete the request

			 * in the worker. Also update bytes_done to account for

			 * the bytes already written.

			 */

			iov_iter_save_state(&s->iter, &s->iter_state);

			ret = io_setup_async_rw(req, iovec, s, true);



			rw = req->async_data;

			if (rw)

				rw->bytes_done += ret2;



			return ret ? ret : -EAGAIN;

		}

done:

		ret = kiocb_done(req, ret2, issue_flags);

	} else {