Re: unmounting a filesystem safely that doesn't exist anymore
On Mon, Jun 12, 2006 at 04:44:48PM -0400, Zaphod Beeblebrox wrote: On 6/12/06, Ulrich Spoerlein [EMAIL PROTECTED] wrote: Björn König wrote: I did a mistake: I unplugged my digital camera accidentally before I unmounted the filesystem. *doh* This happens very often, because I'm very scatterbrained. =) The kernel will panic and all filesystems remain unclean in any case now. I know that this is a well know issue and in past discussions you stated that this behaviour is intended and won't be changed ad hoc. I just want to know if somebody knows a workaround or small trick that prevents the other filesystems from being unclean on next boot-up. You might give the automounter (am-utils) a whirl. They are very confusing to set up, but you can set the unmount-if-unused timeout to something like 5 seconds. This could narrow the window enough to not panic you system frequently :) That's rather hackish ... especially since this is a common problem and a rather obvious hole in using FreeBSD for noobs. I've been using the automounter to handle these mounts for about three years now. When I started I would be have to run fsck on my memory stick about twice a day. Now it's more like once a month. In short it works. I've got to admit that I agree with the fact that this is a more than rather hackish solution to the problem. The real issue here is that for Unix, filesystems come in two types: Those on hard disks which are perpetually available once they've been mounted once, and those which come from the network which can come and go as they please. The automounter works as a solution to this problem by making a local filesystem on hotplugable hardware look like it's coming from a network. It took me the better part of a day to figure out how to make the automounter work properly in this situation. In my case I was using a UFS formatted memory stick which complicated things. The automounter was coded with the assumption that UFS filesystems only exist on drives that are bolted into the computer. The automounter will gladly mount a UFS volume but because it's a UFS volume it never feels the need to dismount the volume and leave it in a clean state. Another problem is that most tools today makes a similar the assumption about mounted volumes that they didn't graft into the filesystem. So, for example opening up the Nautilus file browser on /amd/ufs0 on my system creates an entry in some magic file somewhere that tells Nautilus to periodically visit that directory. As far as amd is concerned these visits are valid requests to mount the filesystem. The end result is that the filesystem again remains permanently mounted. With MS-DOS FAT filesystems the problem is who mounted the filesystem. Amd mounts my MP3 player read-write on /amd/mp3 perms 777 root:wheel. I use rsync to copy podcasts from a holding directory on my desktop to it. And rsync complains all the time that it can copy the files but it cannot change the date/time. This is because chris:chris cannot change an entry in a directory owned by root:wheel, as it should be. It doesn't sound like I'm trying to sell this but in the long run I actually believe that amd is the best of a bunch of mediocre solutions. I wish however that: Amd didn't make the assumption that a UFS volume was going to be there forever; Gnome could be told that filesystems under /amd or some other programmable mount point will come and go with the wind so don't cache the names; That more applications would understand that there are people using the automounter and that a mount request can be accomplished by a simple: $ ls -l /amd/foo and a umount request can be accomplished by a doing: $ amq -u /amd/foo Look for a followup with configs.g -- Chris -- Chris Hilton chris-at-vindaloo-dot-com All I was doing was trying to get home from work! -- Rosa Parks ___ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: unmounting a filesystem safely that doesn't exist anymore
On 6/12/06, Ulrich Spoerlein [EMAIL PROTECTED] wrote: Björn König wrote: I did a mistake: I unplugged my digital camera accidentally before I unmounted the filesystem. *doh* This happens very often, because I'm very scatterbrained. =) The kernel will panic and all filesystems remain unclean in any case now. I know that this is a well know issue and in past discussions you stated that this behaviour is intended and won't be changed ad hoc. I just want to know if somebody knows a workaround or small trick that prevents the other filesystems from being unclean on next boot-up. You might give the automounter (am-utils) a whirl. They are very confusing to set up, but you can set the unmount-if-unused timeout to something like 5 seconds. This could narrow the window enough to not panic you system frequently :) That's rather hackish ... especially since this is a common problem and a rather obvious hole in using FreeBSD for noobs. It seems that a better solution would be to allow filesystems to be mounted with a 'sync' flag. Or even an ULTRA-sync flag. Meaning strict sync semantics and even 'sync' running against the FS every few seconds. If a filesystem so-mounted completely disappears (or errors out), then it should just go poof as if it was umount -f'd. ___ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: unmounting a filesystem safely that doesn't exist anymore
Peter Jeremy schrieb: On Sat, 2006-Jun-10 19:40:41 +0200, Bjrn Knig wrote: I did a mistake: I unplugged my digital camera accidentally before I unmounted the filesystem. *doh* This happens very often, because I'm very scatterbrained. =) Your best solution may be to use mtools (ports/emulators/mtools) rather than mounting the filesystem. changed ad hoc. I just want to know if somebody knows a workaround or small trick that prevents the other filesystems from being unclean on next boot-up. The only way to do this is to have all the other filesystems mounted read-only. The filesystem clean flag is part of the superblock and is cleared when a filesystem is mounted. It will be set only if the filesystem is cleanly unmounted. Thank you very much for these information. They help me a lot. Björn P.S. I get the feeling questions@ would had been a better place for my question. ;-) ___ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: unmounting a filesystem safely that doesn't exist anymore
Björn König wrote: Hello, I did a mistake: I unplugged my digital camera accidentally before I unmounted the filesystem. *doh* This happens very often, because I'm very scatterbrained. =) The kernel will panic and all filesystems remain unclean in any case now. I know that this is a well know issue and in past discussions you stated that this behaviour is intended and won't be changed ad hoc. I just want to know if somebody knows a workaround or small trick that prevents the other filesystems from being unclean on next boot-up. You might give the automounter (am-utils) a whirl. They are very confusing to set up, but you can set the unmount-if-unused timeout to something like 5 seconds. This could narrow the window enough to not panic you system frequently :) Ulrich Spoerlein -- PGP Key ID: 20FEE9DD Encrypted mail welcome! Fingerprint: AEC9 AF5E 01AC 4EE1 8F70 6CBD E76E 2227 20FE E9DD Which is worse: ignorance or apathy? Don't know. Don't care. pgptDKFK0qUnN.pgp Description: PGP signature
Re: unmounting a filesystem safely that doesn't exist anymore
On Sat, 2006-Jun-10 19:40:41 +0200, Bjrn Knig wrote: I did a mistake: I unplugged my digital camera accidentally before I unmounted the filesystem. *doh* This happens very often, because I'm very scatterbrained. =) Your best solution may be to use mtools (ports/emulators/mtools) rather than mounting the filesystem. changed ad hoc. I just want to know if somebody knows a workaround or small trick that prevents the other filesystems from being unclean on next boot-up. The only way to do this is to have all the other filesystems mounted read-only. The filesystem clean flag is part of the superblock and is cleared when a filesystem is mounted. It will be set only if the filesystem is cleanly unmounted. -- Peter Jeremy ___ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to [EMAIL PROTECTED]
unmounting a filesystem safely that doesn't exist anymore
Hello, I did a mistake: I unplugged my digital camera accidentally before I unmounted the filesystem. *doh* This happens very often, because I'm very scatterbrained. =) The kernel will panic and all filesystems remain unclean in any case now. I know that this is a well know issue and in past discussions you stated that this behaviour is intended and won't be changed ad hoc. I just want to know if somebody knows a workaround or small trick that prevents the other filesystems from being unclean on next boot-up. Regards Björn ___ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to [EMAIL PROTECTED]
