Messages in this thread | | | Date | Thu, 07 Sep 2006 21:33:54 -0700 | From | Badari Pulavarty <> | Subject | Re: [RFC][PATCH] set_page_buffer_dirty should skip unmapped buffers |
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Jan Kara wrote: >>> Ugh! Are you sure? For this path the buffer must be attached (only) to >>> the running transaction. But then how the commit code comes to it? >>> Somebody would have to even manage to refile the buffer from the >>> committing transaction to the running one while the buffer is in wbuf[]. >>> Could you check whether someone does __journal_refile_buffer() on your >>> marked buffers, please? Or whether we move buffer to BJ_Locked list in >>> the write_out_data: loop? Thanks. >>> >>> >>> >> I added more debug in __journal_refile_buffer() to see if the marked >> buffers are getting refiled. I am able to reproduce the problem, >> but I don't see any debug including my original prints. (It looks as >> if none of my debug code exists) - its really confusing. >> >> I will keep looking and get back to you. >> > I've been looking more at the code and I have revived my patch fixing > this part of the code. I've mildly tested the patch. Could you also give > it a try? Thanks. > > Honza > > ------------------------------------------------------------------------ > > Original commit code assumes, that when a buffer on BJ_SyncData list is locked, > it is being written to disk. But this is not true and hence it can lead to a > potential data loss on crash. Also the code didn't count with the fact that > journal_dirty_data() can steal buffers from committing transaction and hence > could write buffers that no longer belong to the committing transaction. > Finally it could possibly happen that we tried writing out one buffer several > times. > > The patch below tries to solve these problems by a complete rewrite of the data > commit code. We go through buffers on t_sync_datalist, lock buffers needing > write out and store them in an array. Buffers are also immediately refiled to > BJ_Locked list or unfiled (if the write out is completed). When the array is > full or we have to block on buffer lock, we submit all accumulated buffers for > IO. > > Signed-off-by: Jan Kara <jack@suse.cz> > > I have been running 4+ hours with this patch and seems to work fine. I haven't hit any assert yet :)
I will let it run till tomorrow. I will let you know, how it goes.
Thanks, Badari
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