On Tue, Mar 15, 2022 at 09:26:46AM -0700, dai.ngo@xxxxxxxxxx wrote:
>
> On 3/15/22 8:02 AM, J. Bruce Fields wrote:
> >On Fri, Mar 11, 2022 at 06:13:27PM -0800, Dai Ngo wrote:
> >>Add callout function nfsd4_lm_lock_expired for lm_lock_expired.
> >>If lock request has conflict with courtesy client then expire the
> >>courtesy client and return no conflict to caller.
> >>
> >>Signed-off-by: Dai Ngo <dai.ngo@xxxxxxxxxx>
> >>---
> >> fs/nfsd/nfs4state.c | 37 +++++++++++++++++++++++++++++++++++++
> >> 1 file changed, 37 insertions(+)
> >>
> >>diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> >>index a65d59510681..583ac807e98d 100644
> >>--- a/fs/nfsd/nfs4state.c
> >>+++ b/fs/nfsd/nfs4state.c
> >>@@ -6578,10 +6578,47 @@ nfsd4_lm_notify(struct file_lock *fl)
> >> }
> >> }
> >>+/**
> >>+ * nfsd4_lm_lock_expired - check if lock conflict can be resolved.
> >>+ *
> >>+ * @fl: pointer to file_lock with a potential conflict
> >>+ * Return values:
> >>+ * %false: real conflict, lock conflict can not be resolved.
> >>+ * %true: no conflict, lock conflict was resolved.
> >>+ *
> >>+ * Note that this function is called while the flc_lock is held.
> >>+ */
> >>+static bool
> >>+nfsd4_lm_lock_expired(struct file_lock *fl)
> >>+{
> >>+ struct nfs4_lockowner *lo;
> >>+ struct nfs4_client *clp;
> >>+ bool rc = false;
> >>+
> >>+ if (!fl)
> >>+ return false;
> >>+ lo = (struct nfs4_lockowner *)fl->fl_owner;
> >>+ clp = lo->lo_owner.so_client;
> >>+
> >>+ /* need to sync with courtesy client trying to reconnect */
> >>+ spin_lock(&clp->cl_cs_lock);
> >>+ if (test_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags))
> >>+ rc = true;
> >>+ else {
> >>+ if (test_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags)) {
> >>+ set_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags);
> >>+ rc = true;
> >>+ }
> >>+ }
> >I'd prefer:
> >
> > if (test_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags))
> > set_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags);
>
> we also need to set rc to true here.
No, the next line does it because we set the EXPIRED bit.
--b.
>
> > if (test_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags))
> > rc = true;
>
> With v16 we need to check for NFSD4_CLIENT_EXPIRED first then
> NFSD4_CLIENT_COURTESY because both flags can be set. In the
> next patch version, we will clear NFSD4_CLIENT_COURTESY when
> setting NFSD4_CLIENT_EXPIRED so the order of check does not
> matter.
>
> >
> >Same result, but more compact and straightforward, I think.
>
> Chuck wants to replace the bits used for courtesy client in
> cl_flags with a separate u8 field so it does not have to use
> bit operation to set/test.
>
> -Dai
>
> >
> >--b.
> >
> >>+ spin_unlock(&clp->cl_cs_lock);
> >>+ return rc;
> >>+}
> >>+
> >> static const struct lock_manager_operations nfsd_posix_mng_ops = {
> >> .lm_notify = nfsd4_lm_notify,
> >> .lm_get_owner = nfsd4_lm_get_owner,
> >> .lm_put_owner = nfsd4_lm_put_owner,
> >>+ .lm_lock_expired = nfsd4_lm_lock_expired,
> >> };
> >> static inline void
> >>--
> >>2.9.5
