Yang, (Sorry if I've used your last name lately)
Am 20.08.2015 um 05:00 schrieb Dongsheng Yang:
On 08/20/2015 04:35 AM, Richard Weinberger wrote:
Currently UBIFS does not support direct IO, but some applications
blindly use the O_DIRECT flag.
Instead of failing upon open() we can do better and fall back
to buffered IO.
Hmmmm, to be honest, I am not sure we have to do it as Dave
suggested. I think that's just a work-around for current fstests.
IMHO, perform a buffered IO when user request direct IO without
any warning sounds not a good idea. Maybe adding a warning would
make it better.
Well, how would you inform the user?
A printk() to dmesg is useless are the vast majority of open()
callers do not check dmesg... :)
Major filesystems implement ->direct_IO these days and having
a "return 0"-stub seems to be legit.
For example exofs does too. So, I really don't consider it a work around.
I think we need more discussion about AIO&DIO in ubifs, and actually
I have a plan for it. But I have not listed the all cons and pros of
it so far.
Sure, having a real ->direct_IO would be be best solution.
My patch won't block this.
Thanks,
//richard
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