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Commit 22b814fd authored by Miklos Szeredi's avatar Miklos Szeredi Committed by Greg Kroah-Hartman
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fuse: release pipe buf after last use 



commit 473441720c8616dfaf4451f9c7ea14f0eb5e5d65 upstream.

Checking buf->flags should be done before the pipe_buf_release() is called
on the pipe buffer, since releasing the buffer might modify the flags.

This is exactly what page_cache_pipe_buf_release() does, and which results
in the same VM_BUG_ON_PAGE(PageLRU(page)) that the original patch was
trying to fix.

Reported-by: default avatarJustin Forbes <jmforbes@linuxtx.org>
Fixes: 712a951025c0 ("fuse: fix page stealing")
Cc: <stable@vger.kernel.org> # v2.6.35
Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 2350cffd

fs/fuse/dev.c

+5 −5
Original line number Original line Diff line number Diff line
@@ -905,17 +905,17 @@ static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep) 
		goto out_put_old;

		goto out_put_old;

	}

	}





	get_page(newpage);



	if (!(buf->flags & PIPE_BUF_FLAG_LRU))

		lru_cache_add_file(newpage);



	/*

	/*

	 * Release while we have extra ref on stolen page.  Otherwise

	 * Release while we have extra ref on stolen page.  Otherwise

	 * anon_pipe_buf_release() might think the page can be reused.

	 * anon_pipe_buf_release() might think the page can be reused.

	 */

	 */

	pipe_buf_release(cs->pipe, buf);

	pipe_buf_release(cs->pipe, buf);





	get_page(newpage);



	if (!(buf->flags & PIPE_BUF_FLAG_LRU))

		lru_cache_add_file(newpage);



	err = 0;

	err = 0;

	spin_lock(&cs->req->waitq.lock);

	spin_lock(&cs->req->waitq.lock);

	if (test_bit(FR_ABORTED, &cs->req->flags))

	if (test_bit(FR_ABORTED, &cs->req->flags))