Re: Change in multiple NFS mount behavior in 2.6.19?

[Mike Accetta <maccetta@laurelnetworks.com>]

Randy Dunlap wrote:
> On Fri, 15 Dec 2006 23:46:28 -0500 Mike Accetta wrote:
> 
>> After upgrading an NFS client from 2.6.18 to 2.6.19 (and also with 
>> 2.6.19.1) we see a change in behavior of multiple NFS mounts against the 
>> same server (running 2.4.20 in this case).  With 2.6.18 we could mount 
>> different pieces of the same remote file system with distinct read-only 
>> and read-write attributes at corresponding places on the client.  With 
>> 2.6.19 if the first mount is read-only, subsequent mounts seem to 
>> inherit the read-only status even though not explicitly mounted read-only.
>>
>> If I did the "git bisect" properly, the behavior changed with commit
>> 54ceac4515986030c2502960be620198dd8fe25b and the description of this 
>> commit seems like it could indeed have caused this behavior, but perhaps 
>> not intentionally. I believe the client is making NFS V2 calls. Also, I 
>> am still able to issue a "mount -o remount,rw" on the client to regain 
>> read-write capability.  Was this a regression or is this now the 
>> expected behavior for multiple NFS client mounts in 2.6.19?
>> -- 
> 
> That would correspond to this bugzilla item, which explains
> that multiple mount semantics for one filesystem are all shared.
> 
> http://bugzilla.kernel.org/show_bug.cgi?id=7655

OK.  I didn't think to search bugzilla as I hadn't seen anything go by on the 
list.   Since this is now the expected behavior, I'll have to think about how 
to re-architect things.  Thanks for the pointer.
-- 
Mike Accetta

ECI Telecom Ltd.
Data Networking Division (previously Laurel Networks)