Re: [PATCH 3/3] f2fs: fix inode rwsem regression

Chao Yu
2019-09-12T06:19:07Z

On 2019/9/12 0:45, Goldwyn Rodrigues wrote:
> From: Goldwyn Rodrigues <rgoldwyn@suse.com>
>
> This is similar to 942491c9e6d6 ("xfs: fix AIM7 regression")
> Apparently our current rwsem code doesn't like doing the trylock, then
> lock for real scheme. So change our read/write methods to just do the
> trylock for the RWF_NOWAIT case.
>
> We don't need a check for IOCB_NOWAIT and !direct-IO because it
> is checked in generic_write_checks().
>
> Fixes: b91050a80cec ("f2fs: add nowait aio support")
> Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
> ---
> fs/f2fs/file.c | 10 +++-------
> 1 file changed, 3 insertions(+), 7 deletions(-)
>
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index 3e58a6f697dd..c6f3ef815c05 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -3134,16 +3134,12 @@ static ssize_t f2fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
> goto out;
> }
>
> - if ((iocb->ki_flags & IOCB_NOWAIT) && !(iocb->ki_flags & IOCB_DIRECT)) {
> - ret = -EINVAL;
> - goto out;
> - }

We have removed above redundant check, could you rebase to dev-test branch of
Jaegeuk's git tree?

Otherwise it looks good to me.

Thanks,

> -
> - if (!inode_trylock(inode)) {
> - if (iocb->ki_flags & IOCB_NOWAIT) {
> + if (iocb->ki_flags & IOCB_NOWAIT) {
> + if (!inode_trylock(inode)) {
> ret = -EAGAIN;
> goto out;
> }
> + } else {
> inode_lock(inode);
> }
>
>