tree ab9ec0cbd2636e3089db7a10ec49756cce702820
parent 030d794bf49855f5e2a9e8dfbfad34211d1eb08b
author J. Bruce Fields <bfields@redhat.com> 1366056226 -0400
committer J. Bruce Fields <bfields@redhat.com> 1367007495 -0400

nfsd: fix EXDEV checking in rename

We again check for the EXDEV a little later on, so the first check is
redundant.  This check is also slightly racier, since a badly timed
eviction from the export cache could leave us with the two fh_export
pointers pointing to two different cache entries which each refer to the
same underlying export.

It's better to compare vfsmounts as the later check does, but that
leaves a minor security hole in the case where the two exports refer to
two different directories especially if (for example) they have
different root-squashing options.

So, compare ex_path.dentry too.

Reported-by: Joe Habermann <joe.habermann@gmail.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>