Commit 60392573 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Dave Chinner
Browse files

direct-io: add flag to allow aio writes beyond i_size 



Some filesystems can handle direct I/O writes beyond i_size safely,
so allow them to opt into receiving them.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
parent 38dbfb59

fs/direct-io.c

+12 −6
Original line number Diff line number Diff line
@@ -1194,13 +1194,19 @@ do_blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode, 
	}



	/*

	 * For file extending writes updating i_size before data

	 * writeouts complete can expose uninitialized blocks. So

	 * even for AIO, we need to wait for i/o to complete before

	 * returning in this case.

	 * For file extending writes updating i_size before data writeouts

	 * complete can expose uninitialized blocks in dumb filesystems.

	 * In that case we need to wait for I/O completion even if asked

	 * for an asynchronous write.

	 */

	dio->is_async = !is_sync_kiocb(iocb) && !((rw & WRITE) &&

		(end > i_size_read(inode)));

	if (is_sync_kiocb(iocb))

		dio->is_async = false;

	else if (!(dio->flags & DIO_ASYNC_EXTEND) &&

            (rw & WRITE) && end > i_size_read(inode))

		dio->is_async = false;

	else

		dio->is_async = true;



	dio->inode = inode;

	dio->rw = rw;

include/linux/fs.h

+3 −0
Original line number Diff line number Diff line
@@ -2527,6 +2527,9 @@ enum { 


	/* filesystem does not support filling holes */

	DIO_SKIP_HOLES	= 0x02,



	/* filesystem can handle aio writes beyond i_size */

	DIO_ASYNC_EXTEND = 0x04,

};



void dio_end_io(struct bio *bio, int error);