From: Chuck Lever chuck.lever@oracle.com
commit ce3c4ad7f4ce5db7b4f08a1e237d8dd94b39180b upstream.
nfsd4_release_lockowner() holds clp->cl_lock when it calls check_for_locks(). However, check_for_locks() calls nfsd_file_get() / nfsd_file_put() to access the backing inode's flc_posix list, and nfsd_file_put() can sleep if the inode was recently removed.
Let's instead rely on the stateowner's reference count to gate whether the release is permitted. This should be a reliable indication of locks-in-use since file lock operations and ->lm_get_owner take appropriate references, which are released appropriately when file locks are removed.
Reported-by: Dai Ngo dai.ngo@oracle.com Signed-off-by: Chuck Lever chuck.lever@oracle.com Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/nfsd/nfs4state.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-)
--- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -6894,16 +6894,12 @@ nfsd4_release_lockowner(struct svc_rqst if (sop->so_is_open_owner || !same_owner_str(sop, owner)) continue;
- /* see if there are still any locks associated with it */ - lo = lockowner(sop); - list_for_each_entry(stp, &sop->so_stateids, st_perstateowner) { - if (check_for_locks(stp->st_stid.sc_file, lo)) { - status = nfserr_locks_held; - spin_unlock(&clp->cl_lock); - return status; - } + if (atomic_read(&sop->so_count) != 1) { + spin_unlock(&clp->cl_lock); + return nfserr_locks_held; }
+ lo = lockowner(sop); nfs4_get_stateowner(sop); break; }