getcwd lies on/under nfs4-mounted zfs dataset

[Rick Macklem]

pluknet at gmail.com wrote:
> Hi.
> 
> We stuck with the problem getting wrong current directory path
> when sitting on/under zfs dataset filesystem mounted over NFSv4.
> Both nfs server and client are 10.0-CURRENT from December or so.
> 
> The component path "user3" unexpectedly appears to be "." (dot).
> nfs-client:/home/user3 # pwd
> /home/.
> nfs-client:/home/user3/var/run # pwd
> /home/./var/run
> 
Yep, it was broken for UFS too. I think the attached patch for
the client might fix it. (It fixes a trivial test case for UFS,
but I haven't gone through the code to check if it might break
something else.)

I vaguely recall bumping into a non-FreeBSD server that only
returned the Mounted_on_fileno attribute for mount points at
a testing bakeathon and hacking around the problem that caused.
(I think that hack made it into head, oops.;-)

So, I wouldn't test this patch for a production type system,
but if you can test it, that would be great.

Sorry about the breakage, rick

> nfs-client:~ # procstat -f 3225
> PID COMM FD T V FLAGS REF OFFSET PRO NAME
> 3225 a.out text v r r-------- - - - /home/./var/a.out
> 3225 a.out ctty v c rw------- - - - /dev/pts/2
> 3225 a.out cwd v d r-------- - - - /home/./var
> 3225 a.out root v d r-------- - - - /
> 
> The used setup follows.
> 
> 1. NFS Server with local ZFS:
> # cat /etc/exports
> V4: / -sec=sys
> 
> # zfs list
> pool1 10.4M 122G 580K /pool1
> pool1/user3 on /pool1/user3 (zfs, NFS exported, local, nfsv4acls)
> 
> Exports list on localhost:
> /pool1/user3 109.70.28.0
> /pool1 109.70.28.0
> 
> # zfs get sharenfs pool1/user3
> NAME PROPERTY VALUE SOURCE
> pool1/user3 sharenfs -alldirs -maproot=root -network=109.70.28.0/24
> local
> 
> 2. pool1 is mounted on NFSv4 client:
> nfs-server:/pool1 on /home (nfs, noatime, nfsv4acls)
> 
> So that on NFS client the "pool1/user3" dataset comes at /home/user3.
> / - ufs
> /home - zpool-over-nfsv4
> /home/user3 - zfs dataset "pool1/user3"
> 
> At the same time it works as expected when we're not on zfs dataset,
> but directly on its parent zfs pool (also over NFSv4), e.g.
> nfs-client:/home/non_dataset_dir # pwd
> /home/non_dataset_dir
> 
> The ls command works as expected:
> nfs-client:/# ls -dl /home/user3/var/
> drwxrwxrwt+ 6 root wheel 6 Jan 10 16:19 /home/user3/var/
> 
> --
> wbr,
> pluknet
> _______________________________________________
> freebsd-fs at freebsd.org mailing list
> http://lists.freebsd.org/mailman/listinfo/freebsd-fs
> To unsubscribe, send any mail to "freebsd-fs-unsubscribe at freebsd.org"
-------------- next part --------------
A non-text attachment was scrubbed...
Name: client-getcwd.patch
Type: text/x-patch
Size: 795 bytes
Desc: not available
URL: <http://lists.freebsd.org/pipermail/freebsd-fs/attachments/20130115/6ea7b657/attachment.bin>