On Wed, Mar 02, 2016 at 09:47:44PM +0000, Al Viro wrote: > On Wed, Mar 02, 2016 at 01:01:54PM -0600, Frank Sorenson wrote: > Let's provide a sane stable ABI for the things it's going to be > used for. Because _this_ is very likely to end up with > "something needs to keep track of those events boot-to-shutdown" -> > "something in systemd guts will be keeping track of those and > broadcasting the collected information on state over dbus for the > rest of dbus-infested system to see" -> "touch any details and you > break real userland code" -> "it's cast in stone forever". With > systemd folks not particularly happy about the details, but even > less happy about the need to make the already grotty code parsing > those depend on the kernel version. > > And as much as I don't like Lennart et.al., in this case they would > be perfectly justified. Information in question is potentially interesting, > due to the form it is presented in one really needs to keep track of all > messages since boot to make any use of it and it's clearly a job for > a long-running daemon to collect those - nothing else would be able to. > And once such a daemon starts using that, its authors would have very good > reasons to demand the fucking ABI to be fucking stable. After all, they > weren't the ones who came up with the nasty details we might want to change. > > So let's get it right. Preferably - without need for boot-to-shutdown > tracking just to mirror the state. What do we really want? > > * an ioctl to query the state (frozen/freezing/not frozen) for something in > util-linux to use? > > * /proc/fs/freezing and /proc/fs/frozen, with ->s_id of affected filesystems > or, pehaps, one file with (frozen|freezing) + ->s_id? > > * ability to audit on state changes? That'd need some thought re what to > do when some joker freezes the fs syslogd is logging to... > > * something else entirely? Such as: https://lkml.org/lkml/2015/6/16/456 Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
