Messages in this thread | | | Date | Thu, 12 Oct 2006 14:55:17 -0700 | From | Badari Pulavarty <> | Subject | Re: 2.6.18 ext3 panic. |
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Eric Sandeen wrote: > Andrew Morton wrote: > > >> On Thu, 12 Oct 2006 14:28:20 +0200 >> Jan Kara <jack@suse.cz> wrote: >> >> >> >>> Where can we call >>> journal_dirty_data() without PageLock? >>> >>> >> block_write_full_page() will unlock the page, so ext3_writepage() >> will run journal_dirty_data_fn() against an unlocked page. >> >> I haven't looked into the exact details of the race, but it should >> be addressable via jbd_lock_bh_state() or j_list_lock coverage >> > I'm testing with something like this now; seem sane? > > journal_dirty_data & journal_unmap_data both check do > jbd_lock_bh_state(bh) close to the top... journal_dirty_data_fn has checked > buffer_mapped before getting into journal_dirty_data, but that state may > change before the lock is grabbed. Similarly re-check after we drop the lock. > > This is exactly the solution I proposed earlier (to check buffer_mapped() before calling submit_bh()). But at that time, Jan pointed out that the whole handling is wrong.
But if this is the only case we need to handle, I am okay with this band aid :)
Thanks, Badari
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