Re: [PATCH v2 12/12] btrfs: enable nowait async buffered writes

Filipe Manana
2022-09-08T10:15:03Z

On Thu, Sep 8, 2022 at 1:29 AM Stefan Roesch <shr@fb.com> wrote:
>
> Enable nowait async buffered writes in btrfs_do_write_iter() and
> btrfs_file_open().

This is too terse, see below.

>
> Signed-off-by: Stefan Roesch <shr@fb.com>
> ---
> fs/btrfs/file.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
> index fd42ba9de7a7..887497fd524f 100644
> --- a/fs/btrfs/file.c
> +++ b/fs/btrfs/file.c
> @@ -2107,13 +2107,13 @@ ssize_t btrfs_do_write_iter(struct kiocb *iocb, struct iov_iter *from,
> if (BTRFS_FS_ERROR(inode->root->fs_info))
> return -EROFS;
>
> - if ((iocb->ki_flags & IOCB_NOWAIT) && !(iocb->ki_flags & IOCB_DIRECT))
> - return -EOPNOTSUPP;
> -
> if (sync)
> atomic_inc(&inode->sync_writers);
>
> if (encoded) {
> + if (iocb->ki_flags & IOCB_NOWAIT)
> + return -EOPNOTSUPP;

The changelog should provide some rationale about why encoded writes
are not supported.

Thanks.

> +
> num_written = btrfs_encoded_write(iocb, from, encoded);
> num_sync = encoded->len;
> } else if (iocb->ki_flags & IOCB_DIRECT) {
> @@ -3755,7 +3755,7 @@ static int btrfs_file_open(struct inode *inode, struct file *filp)
> {
> int ret;
>
> - filp->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC;
> + filp->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC | FMODE_BUF_WASYNC;
>
> ret = fsverity_file_open(inode, filp);
> if (ret)
> --
> 2.30.2
>

--
Filipe David Manana,

“Whether you think you can, or you think you can't — you're right.”