On 12/23/2011 02:03 PM, Jim Meyering wrote: > Pádraig Brady wrote: >> On 12/23/2011 12:08 PM, Jim Meyering wrote: >>> Pádraig Brady wrote: >>>> On 12/22/2011 11:48 PM, Pádraig Brady wrote: >>>>> On 12/22/2011 09:50 PM, Alan Curry wrote: >>>>>> Bob Proulx writes: >>>>>>> >>>>>>> Jim Meyering wrote: >>>>>>>> Are there so many new remote file systems coming into use now? >>>>>>>> That are not listed in /usr/include/linux/magic.h? >>>>>>> >>>>>>> The past can always be enumerated. The future is always changing. It >>>>>>> isn't possible to have a complete list of future items. It is only >>>>>>> possible to have a complete list of past items. The future is not yet >>>>>>> written. >>>>>> >>>>>> Between past and future is the present, i.e. the currently running >>>>>> kernel. >>>>>> Shouldn't it return an error when you use an interface that isn't >>>>>> implemented >>>>>> by the underlying filesystem? Why doesn't this happen? >>>>> >>>>> That's a fair point. >>>>> >>>>> Eric shouldn't some/all remote file systems in the kernel >>>>> return ENOTSUP for inotify operations? >>>> >>>> Oh right, as Sven points out, >>>> a notification _is_ sent for local processes modifying a remote file. >>>> I guess we'd need a IN_REMOTE flag (send remote events too), which >>>> remote file systems would return ENOTSUP if they don't support that. >>>> That's getting a bit awkward though. >>> >>> I'm thinking of recording[*] which file systems are local and which >>> are remote. >> >> You mean by tagging the table in stat.c with say "(remote)" after the >> hex constant? >> Then use that to build a header for use by tail::fremote() ? > > Yes. > >>> Then we can make tail -f warn when one or more of >>> its file arguments resides on a remote file system. We may finally >>> have to add and document --disable-inotify. >> >> Currently we fall back to polling for remote file systems. >> I'm not sure it's worth warning since it's only a latency difference. > > My original goal was to warn, for unknown file system types, > that the type is unknown (suggesting to report it), and that > tail -f is resorting to the use of polling.
Oh right, warn about unknown. That would make sense. cheers, Pádraig.
