GFS2: Improve bug trap code in ->releasepage() (8f065d36) · Commits · 戴 / test

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:

Steven Whitehouse <swhiteho@redhat.com>

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;

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