[OpenAFS-devel] advisory locks on RO vols

[Matt Elliott]

What happens when the client has file open on a read-only volume and its =
changed due to a vos release?  Was the behavior different if the client =
supported advisory locks?

Matt Elliott
melliott@ncsa.illinois.edu


On Oct 2, 2012, at 8:14 PM, Derrick Brashear <shadow@gmail.com> wrote:

> I don't think there's any problem here, at least I have seen none to =
this point.
>=20
> On Tue, Oct 2, 2012 at 5:54 PM, Andrew Deason <adeason@sinenomine.net> =
wrote:
>> Gerrit 8197 makes the unix client effectively ignore advisory lock
>> requests for files in RO volumes. I'm pretty sure this is okay, but I
>> just wanted to raise it here to give people more of a chance if =
there's
>> any possible issues with that.
>>=20
>> This should be okay, since for an RO vol, there's no writes that we =
can
>> conflict with from another process. There should be no write locks we
>> can conflict with, since a process cannot issue a write lock for a =
file
>> opened read-only, and you can only open files read-only in an RO vol.
>>=20
>> And the fileserver already does not track locks for RO vols, which =
makes
>> me think I'm not missing anything. At some point I thought maybe it
>> would be possible for processes to misuse locks as some kind of =
general
>> IPC mech or something, which ignoring them would disrupt (whereas =
right
>> now they are tracked in-kernel even if not on the fileserver), but...
>> I'm not even sure that's detectable by an application. Since, afaik =
you
>> can only ask if there is a conflicting lock held, not just "are there
>> read locks" or something.
>>=20
>> --
>> Andrew Deason
>> adeason@sinenomine.net
>>=20
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>> OpenAFS-devel mailing list
>> OpenAFS-devel@openafs.org
>> https://lists.openafs.org/mailman/listinfo/openafs-devel
>>=20
>=20
>=20
>=20
> --=20
> Derrick
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>=20