From: Chuck Lever <chuck.lever@xxxxxxxxxx>
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@xxxxxxxxxx>
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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;
}
