Commit 213f6271 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Darrick J. Wong
Browse files

iomap: add a IOMAP_DIO_OVERWRITE_ONLY flag 



Add a flag to signal that only pure overwrites are allowed.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
Reviewed-by: default avatarBrian Foster <bfoster@redhat.com>
Reviewed-by: default avatarDarrick J. Wong <djwong@kernel.org>
Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
parent 2f632965

fs/iomap/direct-io.c

+7 −0
Original line number Diff line number Diff line
@@ -485,6 +485,13 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, 
		iomap_flags |= IOMAP_NOWAIT;

	}



	if (dio_flags & IOMAP_DIO_OVERWRITE_ONLY) {

		ret = -EAGAIN;

		if (pos >= dio->i_size || pos + count > dio->i_size)

			goto out_free_dio;

		iomap_flags |= IOMAP_OVERWRITE_ONLY;

	}



	ret = filemap_write_and_wait_range(mapping, pos, end);

	if (ret)

		goto out_free_dio;

include/linux/iomap.h

+8 −0
Original line number Diff line number Diff line
@@ -122,6 +122,7 @@ struct iomap_page_ops { 
#define IOMAP_FAULT		(1 << 3) /* mapping for page fault */

#define IOMAP_DIRECT		(1 << 4) /* direct I/O */

#define IOMAP_NOWAIT		(1 << 5) /* do not block */

#define IOMAP_OVERWRITE_ONLY	(1 << 6) /* only pure overwrites allowed */



struct iomap_ops {

	/*
@@ -262,6 +263,13 @@ struct iomap_dio_ops { 
 */

#define IOMAP_DIO_FORCE_WAIT	(1 << 0)



/*

 * Do not allocate blocks or zero partial blocks, but instead fall back to

 * the caller by returning -EAGAIN.  Used to optimize direct I/O writes that

 * are not aligned to the file system block size.

  */

#define IOMAP_DIO_OVERWRITE_ONLY	(1 << 1)



ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,

		const struct iomap_ops *ops, const struct iomap_dio_ops *dops,

		unsigned int dio_flags);