Hi,

  I tripped over a crash in reiserfs which happened due to PageSwapCache
page being passed to reiserfs_set_page_dirty(). Now it's not that hard to
make reiserfs_set_page_dirty() check that case but I really wonder: Does it
make sense to call mapping->a_ops->set_page_dirty() for a PageSwapCache
page? The page is going to be written via direct IO so from the POV of the
filesystem there's no need for any dirtiness tracking. Also there are
several ->set_page_dirty() implementations which will spectacularly crash
because they do things like page->mapping->host, or call
__set_page_dirty_buffers() which expects buffer heads in page->private.
Or what is the reason for calling filesystem's set_page_dirty() function?

								Honza
-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR