On Tue, 12 Jul 2005, Jeff Moyer wrote: > ==> Regarding Re: [autofs] [PATCH] autofs 4.1.4 no-unlink patch; Ian Kent > <[EMAIL PROTECTED]> adds: > > raven> On Mon, 11 Jul 2005, Chris Feist wrote: > >> Ian, > >> > >> We've been hearing some reports of autofs removing entire home > >> directories when mounts expire. It appears that this could be some sort > >> of race condition in the walk_tree code, where when the function starts > >> the directory is unmounted and then autofs unlinks files in the the > >> directory that is supposed to be umounted. I've attached a patch to the > >> rm_unwanted_fn which adds some additional checks before we unlink > >> anything, and it prevents autofs from unlinking files (since I'm pretty > >> sure that autofs never creates a regular file). Let me know what you > >> think. > > raven> Yes. There doesn't seem to be enough checking and the !S_ISLNK > raven> doesn't look quite right. Your right, the only objects in the autofs > raven> filesystem are directories and symlinks. > > raven> A mount happening during an expire might lead to this. But it > raven> shouldn't be able to happen due to the nature of the state machine. > > raven> I'll have to keep looking. > > Right, it shouldn't be able to happen, I agree. However, we've seen 2 > occurrences of this in the wild. Even if/when we fix this problem > properly, I would lobby to put in these extra checks. They certainly don't > hurt anything, and they make the code more robust. I certainly wouldn't > like it if autofs deleted all of my files! >
Of course. I'll have a look and publish it as an important patch. It would be good to understand what's happening as well. I've never seen this happen before. I wonder what changes we've done in this area lately. Mind that !S_ISLNK has been there since 4.0.0per?? and looks way wrong. Ian _______________________________________________ autofs mailing list [email protected] http://linux.kernel.org/mailman/listinfo/autofs
