Commit 985b71db authored by Jens Axboe's avatar Jens Axboe Committed by Linus Torvalds
Browse files

iomap: use filemap_range_needs_writeback() for O_DIRECT reads 

For reads, use the better variant of checking for the need to call
filemap_write_and_wait_range() when doing O_DIRECT.  This avoids falling
back to the slow path for IOCB_NOWAIT, if there are no pages to wait for
(or write out).

Link: https://lkml.kernel.org/r/20210224164455.1096727-4-axboe@kernel.dk


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 7a60d6d7

fs/iomap/direct-io.c

+16 −8
Original line number Diff line number Diff line
@@ -487,12 +487,28 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, 
		if (pos >= dio->i_size)

			goto out_free_dio;



		if (iocb->ki_flags & IOCB_NOWAIT) {

			if (filemap_range_needs_writeback(mapping, pos, end)) {

				ret = -EAGAIN;

				goto out_free_dio;

			}

			iomap_flags |= IOMAP_NOWAIT;

		}



		if (iter_is_iovec(iter))

			dio->flags |= IOMAP_DIO_DIRTY;

	} else {

		iomap_flags |= IOMAP_WRITE;

		dio->flags |= IOMAP_DIO_WRITE;



		if (iocb->ki_flags & IOCB_NOWAIT) {

			if (filemap_range_has_page(mapping, pos, end)) {

				ret = -EAGAIN;

				goto out_free_dio;

			}

			iomap_flags |= IOMAP_NOWAIT;

		}



		/* for data sync or sync, we need sync completion processing */

		if (iocb->ki_flags & IOCB_DSYNC)

			dio->flags |= IOMAP_DIO_NEED_SYNC;
@@ -507,14 +523,6 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, 
			dio->flags |= IOMAP_DIO_WRITE_FUA;

	}



	if (iocb->ki_flags & IOCB_NOWAIT) {

		if (filemap_range_has_page(mapping, pos, end)) {

			ret = -EAGAIN;

			goto out_free_dio;

		}

		iomap_flags |= IOMAP_NOWAIT;

	}



	if (dio_flags & IOMAP_DIO_OVERWRITE_ONLY) {

		ret = -EAGAIN;

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