Date: Thu, 31 Jan 2013 19:03:22 +0300 From: Sergey Kandaurov <pluknet@gmail.com> To: Rick Macklem <rmacklem@uoguelph.ca> Cc: freebsd-fs@freebsd.org Subject: Re: getcwd lies on/under nfs4-mounted zfs dataset Message-ID: <CAE-mSOJK-_wex62e3GcHhBcMBJZETuUAU0ZRd4eH8GcN2NrRcg@mail.gmail.com> In-Reply-To: <1171241649.2066788.1358383377496.JavaMail.root@erie.cs.uoguelph.ca> References: <CAE-mSOJk1HbxvF=ZpoSP21b9j65qMov=AE-OM6wcUkbadQeZbw@mail.gmail.com> <1171241649.2066788.1358383377496.JavaMail.root@erie.cs.uoguelph.ca>
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On 17 January 2013 04:42, Rick Macklem <rmacklem@uoguelph.ca> wrote: > pluknet@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 >> > Ok, I've figured out what is going on. The algorithm in libc > works, but vn_fullpath1() doesn't. The latter assumes that > "mount points" are marked with VV_ROOT etc. For the > "pseudo mount points" (which are mount points within the > directory tree on the NFSv4 server), this isn't the case. > > If you: > sysctl debug.disablecwd=1 > sysctl debug.disablefullpath=1 > > it works. (At least for the UFS case I tested.) Thank you very much, Rick! As an interim solution, we've decided to go that way. > > I can't see how this can be made to work correctly > for vn_fullpath1() unless it was re-written to use the > same algorithm that lib/libc/gen/getcwd.c implements. > > I was pretty sure this used to work. Maybe the syscalls > used to be disabled by default or weren't used by the > libc functions? > > Anyhow, sorry about the cofusing posts while I figured > out what was going on, rick > ps: Don't use the patch I posted. It isn't needed and > will break stuff. > >> 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
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