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Commit 8f065d36 authored by Steven Whitehouse's avatar Steven Whitehouse
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GFS2: Improve bug trap code in ->releasepage() 



If the buffer is dirty or pinned, then as well as printing a
warning, we should also refuse to release the page in
question.

Currently this can occur if there is a race between mmap()ed
writers and O_DIRECT on the same file. With the addition of
->launder_page() in the future, we should be able to close
this gap.

Signed-off-by: default avatarSteven Whitehouse <swhiteho@redhat.com>
parent 4f1de018

fs/gfs2/aops.c

+6 −2
Original line number Diff line number Diff line
@@ -1076,8 +1076,8 @@ int gfs2_releasepage(struct page *page, gfp_t gfp_mask) 
		bd = bh->b_private;

		if (bd && bd->bd_ail)

			goto cannot_release;

		gfs2_assert_warn(sdp, !buffer_pinned(bh));

		gfs2_assert_warn(sdp, !buffer_dirty(bh));

		if (buffer_pinned(bh) || buffer_dirty(bh))

			goto not_possible;

		bh = bh->b_this_page;

	} while(bh != head);

	gfs2_log_unlock(sdp);
@@ -1107,6 +1107,10 @@ int gfs2_releasepage(struct page *page, gfp_t gfp_mask) 
	} while (bh != head);



	return try_to_free_buffers(page);



not_possible: /* Should never happen */

	WARN_ON(buffer_dirty(bh));

	WARN_ON(buffer_pinned(bh));

cannot_release:

	gfs2_log_unlock(sdp);

	return 0;