On Sun, May 01, 2022 at 10:38:15AM -0700, Dai Ngo wrote:
> This patch allows expired client with lock state to be in COURTESY
> state. Lock conflict with COURTESY client is resolved by the fs/lock
> code using the lm_lock_expirable and lm_expire_lock callback in the
> struct lock_manager_operations.
>
> If conflict client is in COURTESY state, set it to EXPIRABLE and
> schedule the laundromat to run immediately to expire the client. The
> callback lm_expire_lock waits for the laundromat to flush its work
> queue before returning to caller.
Reviewed-by: J. Bruce Fields <bfields@xxxxxxxxxxxx>
(These searches over hash tables that we're adding in a few places are
inefficient, but I'm assuming it won't matter. And I don't have a
better idea off the top of my head. So I'm fine with just doing this
instead of optimizing prematurely.)
--b.
>
> Signed-off-by: Dai Ngo <dai.ngo@xxxxxxxxxx>
> ---
> fs/nfsd/nfs4state.c | 70 +++++++++++++++++++++++++++++++++++++++++------------
> 1 file changed, 54 insertions(+), 16 deletions(-)
>
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index f369142da79f..4ab7dda44f38 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -5715,39 +5715,51 @@ static void nfsd4_ssc_expire_umount(struct nfsd_net *nn)
> }
> #endif
>
> +/* Check if any lock belonging to this lockowner has any blockers */
> static bool
> -nfs4_has_any_locks(struct nfs4_client *clp)
> +nfs4_lockowner_has_blockers(struct nfs4_lockowner *lo)
> +{
> + struct file_lock_context *ctx;
> + struct nfs4_ol_stateid *stp;
> + struct nfs4_file *nf;
> +
> + list_for_each_entry(stp, &lo->lo_owner.so_stateids, st_perstateowner) {
> + nf = stp->st_stid.sc_file;
> + ctx = nf->fi_inode->i_flctx;
> + if (!ctx)
> + continue;
> + if (locks_owner_has_blockers(ctx, lo))
> + return true;
> + }
> + return false;
> +}
> +
> +static bool
> +nfs4_anylock_blockers(struct nfs4_client *clp)
> {
> int i;
> struct nfs4_stateowner *so;
> + struct nfs4_lockowner *lo;
>
> + if (atomic_read(&clp->cl_delegs_in_recall))
> + return true;
> spin_lock(&clp->cl_lock);
> for (i = 0; i < OWNER_HASH_SIZE; i++) {
> list_for_each_entry(so, &clp->cl_ownerstr_hashtbl[i],
> so_strhash) {
> if (so->so_is_open_owner)
> continue;
> - spin_unlock(&clp->cl_lock);
> - return true;
> + lo = lockowner(so);
> + if (nfs4_lockowner_has_blockers(lo)) {
> + spin_unlock(&clp->cl_lock);
> + return true;
> + }
> }
> }
> spin_unlock(&clp->cl_lock);
> return false;
> }
>
> -/*
> - * place holder for now, no check for lock blockers yet
> - */
> -static bool
> -nfs4_anylock_blockers(struct nfs4_client *clp)
> -{
> - if (atomic_read(&clp->cl_delegs_in_recall) ||
> - !list_empty(&clp->async_copies) ||
> - nfs4_has_any_locks(clp))
> - return true;
> - return false;
> -}
> -
> static void
> nfs4_get_client_reaplist(struct nfsd_net *nn, struct list_head *reaplist,
> struct laundry_time *lt)
> @@ -6712,6 +6724,29 @@ nfsd4_lm_put_owner(fl_owner_t owner)
> nfs4_put_stateowner(&lo->lo_owner);
> }
>
> +/* return pointer to struct nfs4_client if client is expirable */
> +static bool
> +nfsd4_lm_lock_expirable(struct file_lock *cfl)
> +{
> + struct nfs4_lockowner *lo = (struct nfs4_lockowner *)cfl->fl_owner;
> + struct nfs4_client *clp = lo->lo_owner.so_client;
> + struct nfsd_net *nn;
> +
> + if (try_to_expire_client(clp)) {
> + nn = net_generic(clp->net, nfsd_net_id);
> + mod_delayed_work(laundry_wq, &nn->laundromat_work, 0);
> + return true;
> + }
> + return false;
> +}
> +
> +/* schedule laundromat to run immediately and wait for it to complete */
> +static void
> +nfsd4_lm_expire_lock(void)
> +{
> + flush_workqueue(laundry_wq);
> +}
> +
> static void
> nfsd4_lm_notify(struct file_lock *fl)
> {
> @@ -6738,9 +6773,12 @@ nfsd4_lm_notify(struct file_lock *fl)
> }
>
> static const struct lock_manager_operations nfsd_posix_mng_ops = {
> + .lm_mod_owner = THIS_MODULE,
> .lm_notify = nfsd4_lm_notify,
> .lm_get_owner = nfsd4_lm_get_owner,
> .lm_put_owner = nfsd4_lm_put_owner,
> + .lm_lock_expirable = nfsd4_lm_lock_expirable,
> + .lm_expire_lock = nfsd4_lm_expire_lock,
> };
>
> static inline void
> --
> 2.9.5
