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Commit 8191ecd1 authored by Jens Axboe's avatar Jens Axboe
Browse files

splice: fix infinite loop in generic_file_splice_read() 



There's a quirky loop in generic_file_splice_read() that could go
on indefinitely, if the file splice returns 0 permanently (and not
just as a temporary condition). Get rid of the loop and pass
back -EAGAIN correctly from __generic_file_splice_read(), so we
handle that condition properly as well.

Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
parent f4be31ec

fs/splice.c

+6 −25
Original line number Diff line number Diff line
@@ -370,8 +370,10 @@ __generic_file_splice_read(struct file *in, loff_t *ppos, 
			 * for an in-flight io page

			 */

			if (flags & SPLICE_F_NONBLOCK) {

				if (TestSetPageLocked(page))

				if (TestSetPageLocked(page)) {

					error = -EAGAIN;

					break;

				}

			} else

				lock_page(page);
@@ -479,9 +481,8 @@ ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, 
				 struct pipe_inode_info *pipe, size_t len,

				 unsigned int flags)

{

	ssize_t spliced;

	int ret;

	loff_t isize, left;

	int ret;



	isize = i_size_read(in->f_mapping->host);

	if (unlikely(*ppos >= isize))
@@ -491,29 +492,9 @@ ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, 
	if (unlikely(left < len))

		len = left;



	ret = 0;

	spliced = 0;

	while (len && !spliced) {

	ret = __generic_file_splice_read(in, ppos, pipe, len, flags);



		if (ret < 0)

			break;

		else if (!ret) {

			if (spliced)

				break;

			if (flags & SPLICE_F_NONBLOCK) {

				ret = -EAGAIN;

				break;

			}

		}



	if (ret > 0)

		*ppos += ret;

		len -= ret;

		spliced += ret;

	}



	if (spliced)

		return spliced;



	return ret;

}