On Tue 09-05-17 07:22:17, Goldwyn Rodrigues wrote:
> From: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
>
> Return EAGAIN if any of the following checks fail for direct I/O:
> + i_rwsem is lockable
> + Writing beyond end of file (will trigger allocation)
> + Blocks are not allocated at the write location
>
> Signed-off-by: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
The patch looks good. You can add:
Reviewed-by: Jan Kara <jack@xxxxxxx>
Honza
> ---
> fs/ext4/file.c | 20 ++++++++++++++++----
> 1 file changed, 16 insertions(+), 4 deletions(-)
>
> diff --git a/fs/ext4/file.c b/fs/ext4/file.c
> index cefa9835f275..2efdc6d4d3e8 100644
> --- a/fs/ext4/file.c
> +++ b/fs/ext4/file.c
> @@ -216,7 +216,13 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
> return ext4_dax_write_iter(iocb, from);
> #endif
>
> - inode_lock(inode);
> + if (iocb->ki_flags & IOCB_NOWAIT) {
> + if (!inode_trylock(inode))
> + return -EAGAIN;
> + } else {
> + inode_lock(inode);
> + }
> +
> ret = ext4_write_checks(iocb, from);
> if (ret <= 0)
> goto out;
> @@ -235,9 +241,15 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
>
> iocb->private = &overwrite;
> /* Check whether we do a DIO overwrite or not */
> - if (o_direct && ext4_should_dioread_nolock(inode) && !unaligned_aio &&
> - ext4_overwrite_io(inode, iocb->ki_pos, iov_iter_count(from)))
> - overwrite = 1;
> + if (o_direct && !unaligned_aio) {
> + if (ext4_overwrite_io(inode, iocb->ki_pos, iov_iter_count(from))) {
> + if (ext4_should_dioread_nolock(inode))
> + overwrite = 1;
> + } else if (iocb->ki_flags & IOCB_NOWAIT) {
> + ret = -EAGAIN;
> + goto out;
> + }
> + }
>
> ret = __generic_file_write_iter(iocb, from);
> inode_unlock(inode);
> --
> 2.12.0
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
