Commit c3a69024 authored by Al Viro's avatar Al Viro
Browse files

fix ITER_PIPE interaction with direct_IO 



by making sure we call iov_iter_advance() on original
iov_iter even if direct_IO (done on its copy) has returned 0.
It's a no-op for old iov_iter flavours and does the right thing
(== truncation of the stuff we'd allocated, but not filled) in
ITER_PIPE case.  Failures (e.g. -EIO) get caught and dealt with
by cleanup in generic_file_read_iter().

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent a949e639

fs/splice.c

+3 −9
Original line number Diff line number Diff line
@@ -315,15 +315,9 @@ ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, 
		*ppos = kiocb.ki_pos;

		file_accessed(in);

	} else if (ret < 0) {

		if (WARN_ON(to.idx != idx || to.iov_offset)) {

			/*

			 * a bogus ->read_iter() has copied something and still

			 * returned an error instead of a short read.

			 */

		to.idx = idx;

		to.iov_offset = 0;

		iov_iter_advance(&to, 0); /* to free what was emitted */

		}

		/*

		 * callers of ->splice_read() expect -EAGAIN on

		 * "can't put anything in there", rather than -EFAULT.

fs/xfs/xfs_file.c

+1 −1
Original line number Diff line number Diff line
@@ -317,7 +317,7 @@ xfs_file_dio_aio_read( 
	data = *to;

	ret = __blockdev_direct_IO(iocb, inode, target->bt_bdev, &data,

			xfs_get_blocks_direct, NULL, NULL, 0);

	if (ret > 0) {

	if (ret >= 0) {

		iocb->ki_pos += ret;

		iov_iter_advance(to, ret);

	}

mm/filemap.c

+1 −1
Original line number Diff line number Diff line
@@ -1920,7 +1920,7 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter) 
			retval = mapping->a_ops->direct_IO(iocb, &data);

		}



		if (retval > 0) {

		if (retval >= 0) {

			iocb->ki_pos += retval;

			iov_iter_advance(iter, retval);

		}

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