nfsd: split sc_status out of sc_type

sc_type identifies the type of a state - open, lock, deleg, layout - and
also the status of a state - closed or revoked.

This is a bit untidy and could get worse when "admin-revoked" states are
added.  So clean it up.

With this patch, the type is now all that is stored in sc_type.  This is
zero when the state is first added to ->cl_stateids (causing it to be
ignored), and is then set appropriately once it is fully initialised.
It is set under ->cl_lock to ensure atomicity w.r.t lookup.  It is now
never cleared.

sc_type is still a bit-set even though at most one bit is set.  This allows
lookup functions to be given a bitmap of acceptable types.

sc_type is now an unsigned short rather than char.  There is no value in
restricting to just 8 bits.

All the constants now start SC_TYPE_ matching the field in which they
are stored.  Keeping the existing names and ensuring clear separation
from non-type flags would have required something like
NFS4_STID_TYPE_CLOSED which is cumbersome.  The "NFS4" prefix is
redundant was they only appear in NFS4 code, so remove that and change
STID to SC to match the field.

The status is stored in a separate unsigned short named "sc_status".  It
has two flags: SC_STATUS_CLOSED and SC_STATUS_REVOKED.
CLOSED combines NFS4_CLOSED_STID, NFS4_CLOSED_DELEG_STID, and is used
for SC_TYPE_LOCK and SC_TYPE_LAYOUT instead of setting the sc_type to zero.
These flags are only ever set, never cleared.
For deleg stateids they are set under the global state_lock.
For open and lock stateids they are set under ->cl_lock.
For layout stateids they are set under ->ls_lock

nfs4_unhash_stid() has been removed, and we never set sc_type = 0.  This
was only used for LOCK and LAYOUT stids and they now use
SC_STATUS_CLOSED.

Also TRACE_DEFINE_NUM() calls for the various STID #define have been
removed because these things are not enums, and so that call is
incorrect.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

1 files changed, 28 insertions, 12 deletions

diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
index 87c4372ba36a..1d4bf1a7d229 100644
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -88,17 +88,33 @@ struct nfsd4_callback_ops {
  */
 struct nfs4_stid {
 	refcount_t		sc_count;
-#define NFS4_OPEN_STID 1
-#define NFS4_LOCK_STID 2
-#define NFS4_DELEG_STID 4
-/* For an open stateid kept around *only* to process close replays: */
-#define NFS4_CLOSED_STID 8
+
+	/* A new stateid is added to the cl_stateids idr early before it
+	 * is fully initialised.  Its sc_type is then zero.  After
+	 * initialisation the sc_type it set under cl_lock, and then
+	 * never changes.
+	 */
+#define SC_TYPE_OPEN		BIT(0)
+#define SC_TYPE_LOCK		BIT(1)
+#define SC_TYPE_DELEG		BIT(2)
+#define SC_TYPE_LAYOUT		BIT(3)
+	unsigned short		sc_type;
+
+/* state_lock protects sc_status for delegation stateids.
+ * ->cl_lock protects sc_status for open and lock stateids.
+ * ->st_mutex also protect sc_status for open stateids.
+ * ->ls_lock protects sc_status for layout stateids.
+ */
+/*
+ * For an open stateid kept around *only* to process close replays.
+ * For deleg stateid, kept in idr until last reference is dropped.
+ */
+#define SC_STATUS_CLOSED	BIT(0)
 /* For a deleg stateid kept around only to process free_stateid's: */
-#define NFS4_REVOKED_DELEG_STID 16
-#define NFS4_CLOSED_DELEG_STID 32
-#define NFS4_LAYOUT_STID 64
+#define SC_STATUS_REVOKED	BIT(1)
+	unsigned short		sc_status;
+
 	struct list_head	sc_cp_list;
-	unsigned char		sc_type;
 	stateid_t		sc_stateid;
 	spinlock_t		sc_lock;
 	struct nfs4_client	*sc_client;
@@ -672,15 +688,15 @@ extern __be32 nfs4_preprocess_stateid_op(struct svc_rqst *rqstp,
 		stateid_t *stateid, int flags, struct nfsd_file **filp,
 		struct nfs4_stid **cstid);
 __be32 nfsd4_lookup_stateid(struct nfsd4_compound_state *cstate,
-		     stateid_t *stateid, unsigned char typemask,
-		     struct nfs4_stid **s, struct nfsd_net *nn);
+			    stateid_t *stateid, unsigned short typemask,
+			    unsigned short statusmask,
+			    struct nfs4_stid **s, struct nfsd_net *nn);
 struct nfs4_stid *nfs4_alloc_stid(struct nfs4_client *cl, struct kmem_cache *slab,
 				  void (*sc_free)(struct nfs4_stid *));
 int nfs4_init_copy_state(struct nfsd_net *nn, struct nfsd4_copy *copy);
 void nfs4_free_copy_state(struct nfsd4_copy *copy);
 struct nfs4_cpntf_state *nfs4_alloc_init_cpntf_state(struct nfsd_net *nn,
 			struct nfs4_stid *p_stid);
-void nfs4_unhash_stid(struct nfs4_stid *s);
 void nfs4_put_stid(struct nfs4_stid *s);
 void nfs4_inc_and_copy_stateid(stateid_t *dst, struct nfs4_stid *stid);
 void nfs4_remove_reclaim_record(struct nfs4_client_reclaim *, struct nfsd_net *);