On Wed 24-02-21 09:44:55, Jens Axboe wrote:
> For reads, use the better variant of checking for the need to call
> filemap_write_and_wait_range() when doing O_DIRECT. This avoids falling
> back to the slow path for IOCB_NOWAIT, if there are no pages to wait for
> (or write out).
>
> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Looks good to me. Feel free to add:
Reviewed-by: Jan Kara <jack@xxxxxxx>
Honza
> ---
> fs/iomap/direct-io.c | 24 ++++++++++++++++--------
> 1 file changed, 16 insertions(+), 8 deletions(-)
>
> diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
> index e2c4991833b8..8c35a0041f0f 100644
> --- a/fs/iomap/direct-io.c
> +++ b/fs/iomap/direct-io.c
> @@ -487,12 +487,28 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
> if (pos >= dio->i_size)
> goto out_free_dio;
>
> + if (iocb->ki_flags & IOCB_NOWAIT) {
> + if (filemap_range_needs_writeback(mapping, pos, end)) {
> + ret = -EAGAIN;
> + goto out_free_dio;
> + }
> + iomap_flags |= IOMAP_NOWAIT;
> + }
> +
> if (iter_is_iovec(iter))
> dio->flags |= IOMAP_DIO_DIRTY;
> } else {
> iomap_flags |= IOMAP_WRITE;
> dio->flags |= IOMAP_DIO_WRITE;
>
> + if (iocb->ki_flags & IOCB_NOWAIT) {
> + if (filemap_range_has_page(mapping, pos, end)) {
> + ret = -EAGAIN;
> + goto out_free_dio;
> + }
> + iomap_flags |= IOMAP_NOWAIT;
> + }
> +
> /* for data sync or sync, we need sync completion processing */
> if (iocb->ki_flags & IOCB_DSYNC)
> dio->flags |= IOMAP_DIO_NEED_SYNC;
> @@ -507,14 +523,6 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
> dio->flags |= IOMAP_DIO_WRITE_FUA;
> }
>
> - if (iocb->ki_flags & IOCB_NOWAIT) {
> - if (filemap_range_has_page(mapping, pos, end)) {
> - ret = -EAGAIN;
> - goto out_free_dio;
> - }
> - iomap_flags |= IOMAP_NOWAIT;
> - }
> -
> if (dio_flags & IOMAP_DIO_OVERWRITE_ONLY) {
> ret = -EAGAIN;
> if (pos >= dio->i_size || pos + count > dio->i_size)
> --
> 2.30.0
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
