On Thu, Jun 28, 2018 at 06:24:59PM -0500, Steve French wrote: > On Thu, Jun 28, 2018 at 6:21 PM ronnie sahlberg > <ronniesahlberg@xxxxxxxxx> wrote: > > > > On Fri, Jun 29, 2018 at 8:58 AM, Theodore Y. Ts'o via samba-technical > > <samba-technical@xxxxxxxxxxxxxxx> wrote: > > > On Thu, Jun 28, 2018 at 05:37:15PM -0500, Steve French wrote: > > >> Ronnie brought up an interesting point about the problems consistently > > >> configuring file systems (or any Linux module for that matter) so that > > >> reboot doesn't wipe away security or performance tuning changes. > > > > > > In general it's considered best practice to make the file system > > > auto-tune itself as much as possible, because the sad fact is that > > > 99.9999% of the customers aren't going to bother to add any tuning > > > parameters. So there hasn't been a push to try to create something > > > more complex, because it's generally not needed. > > > > True, but in these cases I think we are more looking at server or > > mountpoint specific options than > > actual fs tuning. > > > > For example nfsmount.conf can be used to say "only use NFSv4 when > > accessing server abc" etc. > > For the case of CIFS I could imagine that an administrator might want > > to set "disable smb1 protocol globally" > > Or perhaps > "disable smb1 on " ... various public networks but allow it on > private networks The way the policy is configured depends on the mechanism used to configure the policy. If it's a sysctl or a mount option, then we've already got everything we need. If it's something dynamic in sysfs, then I think you're on your own. FYI, I have been looking at making sysctl be able to work on /sys rather than just /proc/sys (I have a 10 line hack to enable it) so we could re-use it with custom per-mount error config files in /etc/xfs/ for XFS that we inject based on a uevent delivered to udev. It works, but the fact is modifying sysctl in this way exposes it to a whole bunch of stuff sysctl doesn't understand, shouldn't be accessing and/or trying modify. i.e. sysctl is disturbingly dumb, and it gets away with it because of it's restricted scope and API presented by /proc/sys. So, really, I'm probably just going roll our own sysfs config file mechanism into xfs_spaceman (probably based on the new config file parser we have for mkfs.xfs) and hide the mess with a nice, simple xfs_admin interface for udev to call. i.e. roll our own :) Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx
