Messages in this thread | | | Date | Thu, 21 Dec 2006 15:00:02 -0800 (PST) | From | business1 <> | Subject | Re: [RFC PATCH 2/8] rqbased-dm: add block layer hook |
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Kiyoshi Ueda wrote: > > Hi Jens, > > Sorry for the less explanation. > > On Wed, 20 Dec 2006 14:49:24 +0100, Jens Axboe <jens.axboe@oracle.com> > wrote: >> On Tue, Dec 19 2006, Kiyoshi Ueda wrote: >> > This patch adds new "end_io_first" hook in __end_that_request_first() >> > for request-based device-mapper. >> >> What's this for, lack of stacking? > > I don't understand the meaning of "lack of stacking" well but > I guess that it means "Is the existing hook in end_that_request_last() > not enough?" If so, the answer is no. > (If the geuss is wrong, please let me know.) > > The new hook is needed for error handling in dm. > For example, when an error occurred on a request, dm-multipath > wants to try another path before returning EIO to application. > Without the new hook, at the point of end_that_request_last(), > the bios are already finished with error and can't be retried. > > Thanks, > Kiyoshi Ueda > > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > > Look at me im boolin > http://www.thebusinesssuccessgroup.com/Real-Estate-Investment-training.html -- View this message in context: http://www.nabble.com/-RFC-PATCH-2-8--rqbased-dm%3A-add-block-layer-hook-tf2848786.html#a8016586 Sent from the linux-kernel mailing list archive at Nabble.com.
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