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Date: Fri, 22 Jan 2016 15:30:02 -0500
Message-ID: <CAOg9mSTPbx0231RoERbbdeyR+nDCD4wGHHFKAzxmowai8GtNgg@mail.gmail.com>
Subject: Re: Orangefs ABI documentation
From: Mike Marshall <hubcap@omnibond.com>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>
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The userspace daemon (client-core) that reads/writes to the device
restarts automatically if it stops for some reason... I believe active
ops are marked "purged" when this happens, and when client-core
restarts "purged" ops are retried (once)... see the comment
in waitqueue.c "if the operation was purged in the meantime..."

I've tried to rattle Walt and Becky's chains to see if they
can describe it better...

-Mike

On Fri, Jan 22, 2016 at 3:04 PM, Al Viro <viro@zeniv.linux.org.uk> wrote:
> On Fri, Jan 22, 2016 at 02:21:44PM -0500, Mike Marshall wrote:
>> Al...
>>
>> I think that my commit f987f4c28
>> "don't trigger copy_attributes_to_inode from d_revalidate."
>> doesn't really do the job... I think I at least need to
>> write code that checks some of the attributes and
>> fails the revalidate if they got changed via some
>> external process... does that sound right?
>
> Won't your orangefs_revalidate_lookup() spot the changed handle?  Anyway,
> some sanity checks in there might be a good idea - at least "has the
> object type somehow changed without handle going stale?"...
>
> Said that, what should be picking e.g. chmod/chown by external source?
> You don't have ->permission() instances in there, so inode->i_mode is
> used directly by generic_inode_permission()...