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Commit c992fe29 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

io_uring: add fsync support 



Add a new fsync opcode, which either syncs a range if one is passed,
or the whole file if the offset and length fields are both cleared
to zero.  A flag is provided to use fdatasync semantics, that is only
force out metadata which is required to retrieve the file data, but
not others like metadata.

Reviewed-by: default avatarHannes Reinecke <hare@suse.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 2b188cc1

fs/io_uring.c

+54 −0
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ 
 * data that the application could potentially modify, it remains stable.

 *

 * Copyright (C) 2018-2019 Jens Axboe

 * Copyright (c) 2018-2019 Christoph Hellwig

 */

#include <linux/kernel.h>

#include <linux/init.h>
@@ -557,6 +558,56 @@ static int io_nop(struct io_kiocb *req, u64 user_data) 
	return 0;

}



static int io_prep_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe)

{

	int fd;



	/* Prep already done */

	if (req->rw.ki_filp)

		return 0;



	if (unlikely(sqe->addr || sqe->ioprio))

		return -EINVAL;



	fd = READ_ONCE(sqe->fd);

	req->rw.ki_filp = fget(fd);

	if (unlikely(!req->rw.ki_filp))

		return -EBADF;



	return 0;

}



static int io_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe,

		    bool force_nonblock)

{

	loff_t sqe_off = READ_ONCE(sqe->off);

	loff_t sqe_len = READ_ONCE(sqe->len);

	loff_t end = sqe_off + sqe_len;

	unsigned fsync_flags;

	int ret;



	fsync_flags = READ_ONCE(sqe->fsync_flags);

	if (unlikely(fsync_flags & ~IORING_FSYNC_DATASYNC))

		return -EINVAL;



	ret = io_prep_fsync(req, sqe);

	if (ret)

		return ret;



	/* fsync always requires a blocking context */

	if (force_nonblock)

		return -EAGAIN;



	ret = vfs_fsync_range(req->rw.ki_filp, sqe_off,

				end > 0 ? end : LLONG_MAX,

				fsync_flags & IORING_FSYNC_DATASYNC);



	fput(req->rw.ki_filp);

	io_cqring_add_event(req->ctx, sqe->user_data, ret, 0);

	io_free_req(req);

	return 0;

}



static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,

			   const struct sqe_submit *s, bool force_nonblock)

{
@@ -578,6 +629,9 @@ static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req, 
	case IORING_OP_WRITEV:

		ret = io_write(req, s, force_nonblock);

		break;

	case IORING_OP_FSYNC:

		ret = io_fsync(req, s->sqe, force_nonblock);

		break;

	default:

		ret = -EINVAL;

		break;

include/uapi/linux/io_uring.h

+7 −1
Original line number Diff line number Diff line
@@ -24,7 +24,7 @@ struct io_uring_sqe { 
	__u32	len;		/* buffer size or number of iovecs */

	union {

		__kernel_rwf_t	rw_flags;

		__u32		__resv;

		__u32		fsync_flags;

	};

	__u64	user_data;	/* data to be passed back at completion time */

	__u64	__pad2[3];
@@ -33,6 +33,12 @@ struct io_uring_sqe { 
#define IORING_OP_NOP		0

#define IORING_OP_READV		1

#define IORING_OP_WRITEV	2

#define IORING_OP_FSYNC		3



/*

 * sqe->fsync_flags

 */

#define IORING_FSYNC_DATASYNC	(1U << 0)



/*

 * IO completion data structure (Completion Queue Entry)