Hi,
I am currently fiddling around with some nested NFSv4 exports and the differing
behaviour to NFSv3.
The environment is a GPFS 5.0.1 with enabled CES, so Ganesha is used as the NFS
server.
Given the following (pseudo) directory structure:
/gpfs/filesystem1/directory1
/gpfs/filesystem1/directory1/sub-directory1
/gpfs/filesystem1/directory1/sub-directory2
Now to the exports:
/gpfs/filesystem1/directory1 is exported to client1 as read-only.
/gpfs/filesystem1/directory1/sub-directory1 is exported to client2 as
read-write.
client2 is not included in the export for /gpfs/filesystem1/directory1.
Mounting /gpfs/filesystem1/directory1 on client1 works as expected.
Mounting /gpfs/filesystem1/directory1/sub-directory1 on client2 does not work
and results in a permission denied.
If I change the protocol from NFSv4 to NFSv3, it works.
There is a section about nested NFS exports in the mmnfs doc:
Creating nested exports (such as /path/to/folder and /path/to/folder/subfolder)
is strongly discouraged since this might lead to serious issues in data
consistency. Be very cautious when creating and using nested exports.
If there is a need to have nested exports (such as /path/to/folder and
/path/to/folder/inside/subfolder), NFSv4 client that mounts the parent
(/path/to/folder) export will not be able to see the child export subtree
(/path/to/folder/inside/subfolder) unless the same client is explicitly allowed
to access the child export as well. This is okay as long as the client uses
only NFSv4 mounts.
The Linux kernel NFS server and other NFSv4 servers do not show this behaviour.
Is there a way to bypass this with CES/Ganesha? Or is the only solution to add
client2 to /gpfs/filesystem1/directory1?
Regards,
Stefan
--
------------------------------------------------------------------------
Stefan Dietrich Deutsches Elektronen-Synchrotron (IT-Systems)
Ein Forschungszentrum der Helmholtz-Gemeinschaft
Notkestr. 85
phone: +49-40-8998-4696 22607 Hamburg
e-mail: [email protected] Germany
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