[dm-devel] device-mapper mirror module (dm-raid)

["Penguin Lin" <penguin taiwan gmail com>]

Dear all:

Recently I am keeping tracing the device-mapper codes in kernel-2.6.20.1

There are still some question that confuse me...
and I hope to change something in mirror driver...

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1. Is recovery here really necessary ?

Every time when a bio is written to a mirrred target, mirror driver will queue 
this io to the write bio_list whthin the mirror_set, finally a kcopyd will be 
invoke to write this bio to all mirrored device. Is the flow correct?

But... there are nothing doing in  the write callback function (write_callback).... right ?
So in the current version, we won't have any regions that is needed to be recovered.

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2. Should we put all read action into the read bio_list of the mirror_set ?

In mirror_map.... should we put all read requests into the read bio_list of the 
mirror_set after check the return value from log->type->in_sync(), since 
do_read() method does the same thing and it will be invoke when a do_work 
is invoke? Or shoulwe d move all read actions including the checking 
(in mirror_map) to the do_read() function ?

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Thanks for all...
and please forgive my Chinese English..... is too poor....
(hopes some one understand what I am talking about in above...)

regard.