On Mon, Apr 03 2017, Scott Mayhew wrote: > On Mon, 03 Apr 2017, NeilBrown wrote: > >> On Fri, Mar 31 2017, Scott Mayhew wrote: >> >> > These patches aim to make it a little easier to change the mountpoint. >> > Right now if you change the pipefs-directory in /etc/nfs.conf, you still >> > need to manually override the dependencies in the systemd unit files in >> > order for the change to actually work. >> > >> > The first patch moves rpc.idmapd's (mostly) undocumented >> > pipefs-directory from /etc/idmapd.conf to /etc/nfs.conf, which rpc.gssd >> > already can use for it's pipefs-directory configuration. >> > >> > The second patch adds a systemd generator that reads the >> > pipefs-directory configurations from /etc/nfs.conf, and if they differ >> > from the default it will automatically 1) create a systemd mount unit >> > file for the pipefs mountpoint and 2) it will create a drop-in >> > configuration file to override the Requires= and After= directives for >> > that service. >> > >> > I did run into a bit of a snag though. Depsite overriding the >> > dependencies for both idmapd and gssd, I wind up with two pipefs >> > filesystems mounted: >> > >> > [root@coeurl ~]# grep pipefs /proc/mounts >> > sunrpc /var/lib/nfs/rpc_pipefs rpc_pipefs rw,relatime 0 0 >> > sunrpc /run/rpc_pipefs rpc_pipefs rw,relatime 0 0 >> > >> > systemd still shows the dependency on the default pipefs mountpoint: >> > >> > [root@coeurl ~]# systemctl list-dependencies --before var-lib-nfs-rpc_pipefs.mount >> > var-lib-nfs-rpc_pipefs.mount >> > ● ├─nfs-idmapd.service >> > ● └─rpc-gssd.service >> > >> > as well as the new one: >> > >> > [root@coeurl ~]# systemctl list-dependencies --before run-rpc_pipefs.mount >> > run-rpc_pipefs.mount >> > ● ├─nfs-idmapd.service >> > ● └─rpc-gssd.service >> > >> > The drop-in configs to override the pipefs mountpoint look correct. I'm >> > clearing both Requires= and After= before setting them: >> > >> > [root@coeurl ~]# cat /run/systemd/generator/nfs-idmapd.service.d/10-pipefs.conf >> > # Automatically generated by rpc-pipefs-generator >> > >> > [Unit] >> > Requires= >> > Requires=run-rpc_pipefs.mount >> > After= >> > After=run-rpc_pipefs.mount local-fs.target >> > >> > [root@coeurl ~]# cat /run/systemd/generator/rpc-gssd.service.d/10-pipefs.conf >> > # Automatically generated by rpc-pipefs-generator >> > >> > [Unit] >> > Requires= >> > Requires=run-rpc_pipefs.mount >> > After= >> > After=run-rpc_pipefs.mount >> > >> > The generated mount unit file also looks correct: >> > >> > [root@coeurl ~]# cat /run/systemd/generator/run-rpc_pipefs.mount >> > # Automatically generated by rpc-pipefs-generator >> > >> > [Unit] >> > Description=RPC Pipe File System >> > DefaultDependencies=no >> > After=systemd-tmpfiles-setup.service >> > Conflicts=umount.target >> > >> > [Mount] >> > What=sunrpc >> > Where=/run/rpc_pipefs >> > Type=rpc_pipefs >> > >> > systemd shows that the drop-in config was picked up: >> > >> > [root@coeurl ~]# systemctl status nfs-idmapd >> > ● nfs-idmapd.service - NFSv4 ID-name mapping service >> > Loaded: loaded (/usr/lib/systemd/system/nfs-idmapd.service; static; vendor preset: disabled) >> > Drop-In: /run/systemd/generator/nfs-idmapd.service.d >> > └─10-pipefs.conf >> > Active: active (running) since Fri 2017-03-31 16:54:24 EDT; 5min ago >> > Process: 27831 ExecStart=/usr/sbin/rpc.idmapd $RPCIDMAPDARGS (code=exited, status=0/SUCCESS) >> > Main PID: 27832 (rpc.idmapd) >> > Tasks: 1 (limit: 4915) >> > CGroup: /system.slice/nfs-idmapd.service >> > └─27832 /usr/sbin/rpc.idmapd >> > >> > and lsof shows that the correct mountpoint is being used: >> > >> > [root@coeurl ~]# lsof -p 27832 2>/dev/null | grep pipefs >> > rpc.idmap 27832 root 10r DIR 0,42 0 103 /run/rpc_pipefs/nfs >> > >> > The same for gssd: >> > >> > [root@coeurl ~]# systemctl status rpc-gssd >> > ● rpc-gssd.service - RPC security service for NFS client and server >> > Loaded: loaded (/usr/lib/systemd/system/rpc-gssd.service; static; vendor preset: disabled) >> > Drop-In: /run/systemd/generator/rpc-gssd.service.d >> > └─10-pipefs.conf >> > Active: active (running) since Fri 2017-03-31 16:54:29 EDT; 6min ago >> > Process: 27839 ExecStart=/usr/sbin/rpc.gssd $RPCGSSDARGS (code=exited, status=0/SUCCESS) >> > Main PID: 27840 (rpc.gssd) >> > Tasks: 1 (limit: 4915) >> > CGroup: /system.slice/rpc-gssd.service >> > └─27840 /usr/sbin/rpc.gssd >> > >> > [root@coeurl ~]# lsof -p 27840 2>/dev/null | grep pipefs >> > rpc.gssd 27840 root cwd DIR 0,42 0 24637 /run/rpc_pipefs >> > rpc.gssd 27840 root 7r DIR 0,42 0 24637 /run/rpc_pipefs >> > rpc.gssd 27840 root 11u FIFO 0,42 0t0 112 /run/rpc_pipefs/gssd/clntXX/gssd >> > >> > So it looks like systemd is using both sets of dependencies, even though >> > the programs themselves are only looking for what's specified in >> > /etc/nfs.conf. I'm not sure what to do about that. Maybe remove the >> > var-lib-nfs-rpc_pipefs.mount unit as well as the dependencies in the >> > nfs-idmapd.service and rpc-gssd.service files, and have the generator >> > create those automatically as well? >> > >> >> Towards the end of the systemd.unit man page is the text: >> >> Note that dependencies (After=, etc.) cannot be reset to an empty list, >> so dependencies can only be added in drop-ins. If you want to remove >> dependencies, you have to override the entire unit. >> >> >> which is consistent with what you discovered. > > Doh, that's what I get for not reading all the way to the end. > >> >> Maybe create a "rpc_pipefs.target" which >> Requires=var-lib-nfs-rpc_pipefs.mount >> After=var-lib-nfs-rpc_pipefs.mount >> and have all the other unit files specified their dependencies >> against this target. >> >> Then your generator would conditionally create a new "rpc_pipefs.target" >> and matching foo.mount. The new .target would depend in the foo.mount, >> and the service files would already depend on that. >> >> Might work. > > That looks like it works, but what should happen then if programs > were to intentionally specify two different values for the pipefs-directory > in nfs.conf? Or is that something that wouldn't make sense to do and > should be prevented? I can't think of a reason why you'd want more than > one rpc_pipefs filesystem mounted... I agree. I cannot think of any good reason. I'm not sure it would be such a bad idea to fix a mount point at compile time, but not that we have run-time configuration it is safe to stick with it. > > Maybe it would make sense to create a 'global' section and have the > programs all look at that instead of looking in their specific config > sections... or maybe have the program check global section and then a > program-specific section, but include a big fat warning that if you > specify it in the program-specific section then you need to override all > of them with the same value. I support a "global" section of rpc-pipefs mount point. I probably should have put pipefs-directory in a "global" section to start with. I don't recall why I didn't. Thanks, NeilBrown > > -Scott >> >> Thanks, >> NeilBrown >> >> >> > -Scott >> > >> > Scott Mayhew (2): >> > idmapd: move the pipefs-directory config option to nfs.conf >> > systemd: add a generator for the rpc_pipefs mountpoint >> > >> > .gitignore | 1 + >> > nfs.conf | 3 + >> > systemd/Makefile.am | 4 +- >> > systemd/nfs.conf.man | 9 ++ >> > systemd/rpc-pipefs-generator.c | 256 +++++++++++++++++++++++++++++++++++++++++ >> > systemd/rpc-svcgssd.service | 3 +- >> > utils/idmapd/idmapd.c | 35 +++--- >> > utils/idmapd/idmapd.man | 19 ++- >> > 8 files changed, 305 insertions(+), 25 deletions(-) >> > create mode 100644 systemd/rpc-pipefs-generator.c >> > >> > -- >> > 2.9.3 >> > >> > -- >> > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in >> > the body of a message to majordomo@xxxxxxxxxxxxxxx >> > More majordomo info at http://vger.kernel.org/majordomo-info.html
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