Messages in this thread | | | Date | Fri, 9 Aug 2013 14:09:34 -0500 | From | scameron@beardog ... | Subject | Question about REQ_FLUSH and bios with data |
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So, I'm working on a block driver using the make_request_fn interface, and have to handle a bio that comes in with (bi_rw & REQ_FLUSH) set AND data to transfer.
According to Documentation/block/writeback_cache_control.txt:
The REQ_FLUSH flag can be OR ed into the r/w flags of a bio submitted from the filesystem and will make sure the volatile cache of the storage device has been flushed before the actual I/O operation is started.
So I've written code that handles that case, along with the various error cases I might encounter, I think, which leads to my question:
How do I get such a bio with a data transfer AND the REQ_FLUSH bit set to come into the driver? Just wondering how to test this case.
Thanks,
(I cc'ed Tejun Heo just because his name is in block/blk-flush.c)
-- steve
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