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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: Hannes Reinecke <hare@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
hifive-unleashed-5.1
Christoph Hellwig 2019-01-11 09:43:02 -07:00 committed by Jens Axboe
parent 2b188cc1bb
commit c992fe2925
2 changed files with 61 additions and 1 deletions
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54
fs/io_uring.c
View File

@ -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;

8
include/uapi/linux/io_uring.h
View File

@ -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)