Effectively, the "ignore" option just ends up recorded in /etc/mnttab for the mount; I haven't seen any evidence that it does anything else; and it looks like a very trivial addition at least to lofs, and probably to the zero-block filesystems as well. Some commands such as df that scan /etc/mnttab will by default ignore entries with the "ignore" option on them. The df command can show all entries, even those with "ignore", with the -a option. The nfsstat command I think also ignores entries with "ignore", but I don't think it has an option to override that; that doesn't matter for what I want to do, because nfs already supports "ignore". Aside from what implements it and those two commands, I don't think anything else uses "ignore" at all; other than appearing in /etc/mnttab, it seems to be a no-op. So adding support for it to additional filesystems in and of itself shouldn't break anything, because nothing has to use it. Even user scripts that read /etc/mnttab would be unaffected until they started using "ignore" on mount commands, in /etc/vfstab, or in automount maps, for filesystems where they presently can't. Unless someone has a mount that presently fails because they're using "ignore" on a filesystem that doesn't support it, nothing should change for them with just adding support for "ignore" to more filesystems. Only adding it to the default /etc/vfstab (which would presumably only affect new installations or maybe LiveUpgrades) or having more commands supply it automatically for some mounts they generate (as automountd apparently does for the autofs mounts it uses to intercept access to automounted directories, and as vold did (I don't know about hald, that's newer than what I'm running) for the nfs "server" it acted like (and mounted) to provide /vol) would be directly visible to users. Which is why I think two cases are perhaps enough: one to add it to the various filesystems that are usually uninteresting in df output and don't already support it, and optionally a later one to add it to the default /etc/vfstab that's supplied for those fs types (and perhaps to automountd for lofs mounts). As one line descriptions, those could be:
* (1) add "ignore" option to filesystems uninteresting in df output and * (2) add "ignore" option to default /etc/vfstab entries for fs types in (1) (and perhaps to automountd lofs mounts) To my mind, (1) is a total no-brainer (and enough that anyone that didn't want to see that stuff could hide it in a clean way, but would have to act explicitly to do so); the first part of (2) requires a bit more thought, and the second part of (2) requires a bit more thought still. A third thing that could be done (but I'd suggest not for lofs) is make "ignore" the default on fd, ctfs, objfs, procfs, devfs, and mntfs; the only problem with that is that there's AFAIK presently no option that overrides or cancels "ignore". So I don't see any particular reason to do the latter for now, although it might be worth thinking about. And it might be worth thinking about that future filesystems should support "ignore" unless there's a specific justification for not doing so. This message posted from opensolaris.org _______________________________________________ opensolaris-code mailing list opensolaris-code@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/opensolaris-code
