On Thu 03-09-20 16:04:13, Gabriel Krisman Bertazi wrote:
> If a DIO read starts past EOF, the kernel won't attempt it, so we don't
> need to flush dirty pages before failing the syscall.
>
> Suggested-by: Jan Kara <jack@xxxxxxx>
> Signed-off-by: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx>
This patch looks good to me. You can add:
Reviewed-by: Jan Kara <jack@xxxxxxx>
Honza
> ---
> fs/direct-io.c | 24 +++++++++++-------------
> 1 file changed, 11 insertions(+), 13 deletions(-)
>
> diff --git a/fs/direct-io.c b/fs/direct-io.c
> index 04aae41323d7..43460c8e0f90 100644
> --- a/fs/direct-io.c
> +++ b/fs/direct-io.c
> @@ -1188,19 +1188,9 @@ do_blockdev_direct_IO(struct kiocb *iocb, struct inode *inode,
> memset(dio, 0, offsetof(struct dio, pages));
>
> dio->flags = flags;
> - if (dio->flags & DIO_LOCKING) {
> - if (iov_iter_rw(iter) == READ) {
> - struct address_space *mapping =
> - iocb->ki_filp->f_mapping;
> -
> - /* will be released by direct_io_worker */
> - inode_lock(inode);
> -
> - retval = filemap_write_and_wait_range(mapping, offset,
> - end - 1);
> - if (retval)
> - goto fail_dio;
> - }
> + if (dio->flags & DIO_LOCKING && iov_iter_rw(iter) == READ) {
> + /* will be released by direct_io_worker */
> + inode_lock(inode);
> }
>
> /* Once we sampled i_size check for reads beyond EOF */
> @@ -1210,6 +1200,14 @@ do_blockdev_direct_IO(struct kiocb *iocb, struct inode *inode,
> goto fail_dio;
> }
>
> + if (dio->flags & DIO_LOCKING && iov_iter_rw(iter) == READ) {
> + struct address_space *mapping = iocb->ki_filp->f_mapping;
> +
> + retval = filemap_write_and_wait_range(mapping, offset, end - 1);
> + if (retval)
> + goto fail_dio;
> + }
> +
> /*
> * For file extending writes updating i_size before data writeouts
> * complete can expose uninitialized blocks in dumb filesystems.
> --
> 2.28.0
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
