2008/5/20 Al Viro <viro@xxxxxxxxxxxxxxxxxx>: > On Tue, May 20, 2008 at 02:06:42PM +0100, Tom Spink wrote: > [snip] > >> I'm just adding people to CC here, but also I had a couple of thoughts >> after reviewing my own code. >> >> I see that do_kern_mount is encapsulated with the BKL, but would it be >> wise to introduce a lock (e.g. a mutex) now for reading and updating >> nr_mounts (and hence calling ->init), rather than wait for the BKL >> removal to come round here? >> >> Also, have I got all the cases where a filesystem is unmounted, >> because I now see umount_tree, and am wondering if decrementing the >> nr_mounts field should be done in here, in the loop of vfsmounts... or >> is it sufficient to leave it at the end of do_umount? Hi Al, > No, you have not and no, doing that anywhere near that layer is hopeless. > > a) Instances of filesystem can easily outlive all vfsmounts, > let alone their attachment to namespaces. I see! Whoops... > b) What should happen if init is done in the middle of exit? Okay, I guess *some* sort of locking is in order. :) > c) Why do we need to bother, anyway? Well, just for the reason I mentioned, I saw the posting about XFS starting threads (when compiled into the kernel), but there's no use of an XFS filesystem at all - there was a suggestion that something like this be tried, so I thought I'd give it a go. Thanks for replying! -- Regards, Tom Spink -- 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
