[Cluster-devel] [PATCH] gfs2: Clean up gfs2_file_write_iter and fix O_SYNC write handling

[Christoph Hellwig]

>  	if (iocb->ki_flags & IOCB_DIRECT) {
>  		struct address_space *mapping = file->f_mapping;
> +		ssize_t buffered, ret2;
>  
> +		ret = gfs2_file_direct_write(iocb, from);
> +		if (ret < 0 || !iov_iter_count(from))
>  			goto out_unlock;
>  
>  		current->backing_dev_info = inode_to_bdi(inode);
> +		buffered = iomap_file_buffered_write(iocb, from, &gfs2_iomap_ops);
>  		current->backing_dev_info = NULL;
> -		if (unlikely(ret < 0))
> +		if (unlikely(buffered <= 0))
>  			goto out_unlock;
>  
>  		/*
>  		 * We need to ensure that the page cache pages are written to
>  		 * disk and invalidated to preserve the expected O_DIRECT
> +		 * semantics.  If the writeback or invalidate fails, only report
> +		 * the direct I/O range as we don't know if the buffered pages
> +		 * made it to disk.
>  		 */
> +		iocb->ki_pos += buffered;
> +		iocb->ki_flags |= IOCB_DSYNC;

I think I'd rather add IOCB_DSYNC before calling
iomap_file_buffered_write, just in case we ever do optimizations for
synchronous I/O there.

> +		ret2 = generic_write_sync(iocb, buffered);
> +		invalidate_mapping_pages(mapping,
> +					 (iocb->ki_pos - buffered) >> PAGE_SHIFT,

This adds a line > 80 chars.

Otherwise this looks fine to me, although I'd just put the fix in the
subject line and just mention the cleanup at the end of the actual
commit log.