On Fri, Oct 11, 2019 at 04:14:31PM +0200, Jan Kara wrote:
> Filesystems do not support doing IO as asynchronous in some cases. For
> example in case of unaligned writes or in case file size needs to be
> extended (e.g. for ext4). Instead of forcing filesystem to wait for AIO
> in such cases, add argument to iomap_dio_rw() which makes the function
> wait for IO completion. This also results in executing
> iomap_dio_complete() inline in iomap_dio_rw() providing its return value
> to the caller as for ordinary sync IO.
>
> Signed-off-by: Jan Kara <jack@xxxxxxx>
> ---
> fs/gfs2/file.c | 6 ++++--
> fs/iomap/direct-io.c | 7 +++++--
> fs/xfs/xfs_file.c | 5 +++--
> include/linux/iomap.h | 3 ++-
> 4 files changed, 14 insertions(+), 7 deletions(-)
>
> diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
> index 997b326247e2..f0caee2b7c00 100644
> --- a/fs/gfs2/file.c
> +++ b/fs/gfs2/file.c
> @@ -732,7 +732,8 @@ static ssize_t gfs2_file_direct_read(struct kiocb *iocb, struct iov_iter *to)
> if (ret)
> goto out_uninit;
>
> - ret = iomap_dio_rw(iocb, to, &gfs2_iomap_ops, NULL);
> + ret = iomap_dio_rw(iocb, to, &gfs2_iomap_ops, NULL,
> + is_sync_kiocb(iocb));
>
> gfs2_glock_dq(&gh);
> out_uninit:
> @@ -767,7 +768,8 @@ static ssize_t gfs2_file_direct_write(struct kiocb *iocb, struct iov_iter *from)
> if (offset + len > i_size_read(&ip->i_inode))
> goto out;
>
> - ret = iomap_dio_rw(iocb, from, &gfs2_iomap_ops, NULL);
> + ret = iomap_dio_rw(iocb, from, &gfs2_iomap_ops, NULL,
> + is_sync_kiocb(iocb));
>
> out:
> gfs2_glock_dq(&gh);
> diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
> index 1fc28c2da279..1bfa0993f705 100644
> --- a/fs/iomap/direct-io.c
> +++ b/fs/iomap/direct-io.c
> @@ -392,7 +392,8 @@ iomap_dio_actor(struct inode *inode, loff_t pos, loff_t length,
> */
> ssize_t
> iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
> - const struct iomap_ops *ops, const struct iomap_dio_ops *dops)
> + const struct iomap_ops *ops, const struct iomap_dio_ops *dops,
> + bool wait_for_completion)
> {
> struct address_space *mapping = iocb->ki_filp->f_mapping;
> struct inode *inode = file_inode(iocb->ki_filp);
> @@ -400,7 +401,6 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
> loff_t pos = iocb->ki_pos, start = pos;
> loff_t end = iocb->ki_pos + count - 1, ret = 0;
> unsigned int flags = IOMAP_DIRECT;
> - bool wait_for_completion = is_sync_kiocb(iocb);
> struct blk_plug plug;
> struct iomap_dio *dio;
>
> @@ -409,6 +409,9 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
> if (!count)
> return 0;
>
> + if (WARN_ON(is_sync_kiocb(iocb) && !wait_for_completion))
> + return -EINVAL;
So far in iomap we've been returning EIO when someone internal screws
up, which (AFAICT) is the case here.
Other than that, the rest of the changes look ok.
--D
> +
> dio = kmalloc(sizeof(*dio), GFP_KERNEL);
> if (!dio)
> return -ENOMEM;
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index 1ffb179f35d2..0739ba72a82e 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -188,7 +188,7 @@ xfs_file_dio_aio_read(
> file_accessed(iocb->ki_filp);
>
> xfs_ilock(ip, XFS_IOLOCK_SHARED);
> - ret = iomap_dio_rw(iocb, to, &xfs_iomap_ops, NULL);
> + ret = iomap_dio_rw(iocb, to, &xfs_iomap_ops, NULL, is_sync_kiocb(iocb));
> xfs_iunlock(ip, XFS_IOLOCK_SHARED);
>
> return ret;
> @@ -547,7 +547,8 @@ xfs_file_dio_aio_write(
> }
>
> trace_xfs_file_direct_write(ip, count, iocb->ki_pos);
> - ret = iomap_dio_rw(iocb, from, &xfs_iomap_ops, &xfs_dio_write_ops);
> + ret = iomap_dio_rw(iocb, from, &xfs_iomap_ops, &xfs_dio_write_ops,
> + is_sync_kiocb(iocb));
>
> /*
> * If unaligned, this is the only IO in-flight. If it has not yet
> diff --git a/include/linux/iomap.h b/include/linux/iomap.h
> index 7aa5d6117936..76b14cb729dc 100644
> --- a/include/linux/iomap.h
> +++ b/include/linux/iomap.h
> @@ -195,7 +195,8 @@ struct iomap_dio_ops {
> };
>
> ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
> - const struct iomap_ops *ops, const struct iomap_dio_ops *dops);
> + const struct iomap_ops *ops, const struct iomap_dio_ops *dops,
> + bool wait_for_completion);
> int iomap_dio_iopoll(struct kiocb *kiocb, bool spin);
>
> #ifdef CONFIG_SWAP
> --
> 2.16.4
>
