Messages in this thread |  | | | Subject | Re: [PATCH 12/13] sysfs: Propagate renames to the vfs on demand | | From | (Eric W. Biederman) | | Date | Sat, 07 Nov 2009 03:57:08 -0800 |
Miklos Szeredi <miklos@szeredi.hu> writes:
> On Fri, 06 Nov 2009, ebiederm@xmission.com (Eric W. Biederman wrote: >> Tejun Heo <tj@kernel.org> writes: >> >> > Hello, >> > >> > Eric W. Biederman wrote: >> >> It isn't what I want but it is what the VFS requires. If let the vfs >> >> continue on it's delusional state we will leak the vfs mount and >> >> everything mounted on top of it, with no way to remove the mounts. > > "umount -l" on the whole thing will clear any submounts up too. > >> > >> > This is caused by not having any way to prevent deletion on >> > directories with submounts, right? How does other distributed >> > filesystems deal with directories with submounts going away underneath >> > it? >> >> NFS does exactly the same thing I am doing. > > Yes, this is a problem for NFS too. You cannot tell the NFS server > "this directory is mounted on some client, don't let anything happen > to it!". Basically the remaining choices are: > > a) let the old path leading up to the mount still be accessible, even > though it doesn't exist anymore on the server (or has been replaced > with something different) > > b) automatically dissolve any submounts if the path disappeard on the > server > > I think Al was arguing in favor of b), while Linus said that mounts > must never just disappear, so a) is better. I don't think an > agreement was reached.
I haven't seen that conversation. I do know it is non-intutive and if you attempt to delete what is a mount point in another mount namespace and it won't go away. (What we do for non-distributed filesystems). So I would favor mount points dissolving if we had the infrastructure.
Regardless the goal for now is to simply catch up with other distributed filesystems.
Eric
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