wrong access rights on NFS mount

[Timo Aaltonen]

Binary package hint: linux-source-2.6.19

Beginning from 2.6.19 there are problems with NFS-mounts. The permissions from the first mount is passed to the others, so for example if the first one is with ro-permissions, all rw-mounts after that from the same server are read-only as well. This is filed against Fedora/RHEL as well. I'll link them here.

I've tried edgy, feisty and now the shiny new 2.6.20-1.1 on feisty. They all behave the same. Dapper works fine.

[Timo Aaltonen (tjaalton)]

Oh, Redhat has 2.6.18, but I think the culprit are the FS-Cache patches that have been merged in 2.6.19 (?) and which RH most likely has in their 2.6.18 (since they were made by a RH employee).

[Timo Aaltonen (tjaalton)]

from nfsv4-mailing list I found some postings by David Howells about FS-Cache, and this patch in particular sounds worrisome:

[PATCH 18/30] NFS: Share NFS superblocks per-protocol per-server per-FSID
http://linux-nfs.org/pipermail/nfsv4/2006-July/004730.html

[Timo Aaltonen (tjaalton)]

two more bugs.. seems that I can't link them directly to this bug since there already is one.

https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=209964
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=217793

[Ben Collins (ben-collins)]

Is this fixed in 2.6.20?

[Timo Aaltonen (tjaalton)]

no, I tested that as well as I said. Anyway, Trond replied and said that this is a feature, not a bug... :

http://linux-nfs.org/pipermail/nfsv4/2006-December/005485.html

so, I don't like the current behavior but if it won't be fixed upstream then this can be closed and make sure that nfs-utils has good documentation of this and other "features" of the linux nfs implementation >:-/

[Timo Aaltonen (tjaalton)]

oh wait, maybe I misread the reply.

[Timo Aaltonen (tjaalton)]

yep, my followup to the thread should hopefully clarify that this is indeed a different situation from the one that Trond points out. So the bug is real, and I'll wait for replies.

[Ben Collins (ben-collins)]

Moved on to 2.6.20 so 2.6.19 will go away.

[Timo Aaltonen (tjaalton)]

the relevant kernel bugzilla entry:

http://bugzilla.kernel.org/show_bug.cgi?id=7612

[Ben Collins (ben-collins)]

According to the explanation on the upstream bug report, this is a logic change in the way the kernel handles multiple mounts of the same remote nfs filesystem.

Not a bug.