Messages in this thread | | | Date | Mon, 24 May 2010 17:47:36 +0100 | From | Al Viro <> | Subject | Re: [PATCH] VFS: fix recent breakage of FS_REVAL_DOT |
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On Mon, May 24, 2010 at 12:21:22PM -0400, Trond Myklebust wrote: > > Can an nfs4 server e.g. have /x/y being a symlink that resolves to /a/b and > > allow mounting of both /x/y/c and /a/b/c? Which path would it return to > > client that has mounted both, walked to some referral point and called > > nfs_do_refmount(), triggering nfs4_proc_fs_locations()? > > > > Trond, Neil? > > When mounting /x/y/c in your example above, the NFSv4 protocol requires > the client itself to resolve the symlink, and then walk down /a/b/c > (looking up component by component), so it will in practice not see > anything other than /a/b/c. > > If it walks down to a referral, and then calls nfs_do_refmount, it will > do the same thing: obtain a path /e/f/g on the new server, and then walk > down that component by component while resolving any symlinks and/or > referrals that it crosses in the process.
Ho-hum... What happens if the same fs is mounted twice on server? I.e. have ext2 from /dev/sda1 mounted on /a and /b on server, then on the client do mount -t nfs foo:/a /tmp/a; mount -t nfs foo:/b /tmp/b. Which path would we get from GETATTR with fs_locations requested, if we do it for /tmp/a/x and /tmp/b/x resp.? Dentry will be the same, since fsid would match.
Or would the server refuse to export things that way?
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