nfsd: only set file_lock.fl_lmops in nfsd4_lockt if a stateowner is found

commit fa82a491275a613b15489aab4b99acecb00958d3 upstream.

nfsd4_lockt does a search for a lockstateowner when building the lock
struct to test. If one is found, it'll set fl_owner to it. Regardless of
whether that happens, it'll also set fl_lmops. Given that this lock is
basically a "lightweight" lock that's just used for checking conflicts,
setting fl_lmops is probably not appropriate for it.

This behavior exposed a bug in DLM's GETLK implementation where it
wasn't clearing out the fields in the file_lock before filling in
conflicting lock info. While we were able to fix this in DLM, it
still seems pointless and dangerous to set the fl_lmops this way
when we may have a NULL lockstateowner.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@pig.fieldses.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index c05284ad76dbc97e61ba15fc89c3f38267e2030a..ddcbed8c790c778b0ea6169007b67d6dd8f60435 100644 (file)
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -2840,7 +2840,6 @@ nfsd4_lockt(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
                file_lock.fl_owner = (fl_owner_t)lockt->lt_stateowner;
        file_lock.fl_pid = current->tgid;
        file_lock.fl_flags = FL_POSIX;
-       file_lock.fl_lmops = &nfsd_posix_mng_ops;
 
        file_lock.fl_start = lockt->lt_offset;
        if ((lockt->lt_length == ~(u64)0) || LOFF_OVERFLOW(lockt->lt_offset, lockt->lt_length))