nfsd4: Move callback setup to callback queue

Instead of creating the new rpc client from a regular server thread,
set a flag, kick off a null call, and allow the null call to do the work
of setting up the client on the callback workqueue.

Use a spinlock to ensure the callback work gets a consistent view of the
callback parameters.

This allows, for example, changing the callback from contexts where
sleeping is not allowed.  I hope it will also keep the locking simple as
we add more session and trunking features, by serializing most of the
callback-specific work.

This also closes a small race where the the new cb_ident could be used
with an old connection (or vice-versa).

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

1 files changed, 8 insertions, 2 deletions

diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
index 2ece6bee65f7..58bc2a63ca14 100644
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -84,7 +84,6 @@ struct nfs4_delegation {
         u32                     dl_type;
         time_t                  dl_time;
 /* For recall: */
-        u32                     dl_ident;
         stateid_t               dl_stateid;
         struct knfsd_fh         dl_fh;
         int                     dl_retries;
@@ -217,10 +216,17 @@ struct nfs4_client {
 
         /* for v4.0 and v4.1 callbacks: */
         struct nfs4_cb_conn     cl_cb_conn;
+#define NFSD4_CLIENT_CB_UPDATE  1
+#define NFSD4_CLIENT_KILL       2
+        unsigned long           cl_cb_flags;
         struct rpc_clnt         *cl_cb_client;
+        u32                     cl_cb_ident;
         atomic_t                cl_cb_set;
         struct nfsd4_callback   cl_cb_null;
 
+        /* for all client information that callback code might need: */
+        spinlock_t              cl_lock;
+
         /* for nfs41 */
         struct list_head        cl_sessions;
         struct nfsd4_clid_slot  cl_cs_slot;     /* create_session slot */
@@ -439,7 +445,7 @@ extern void nfsd4_do_callback_rpc(struct work_struct *);
 extern void nfsd4_cb_recall(struct nfs4_delegation *dp);
 extern int nfsd4_create_callback_queue(void);
 extern void nfsd4_destroy_callback_queue(void);
-extern void nfsd4_set_callback_client(struct nfs4_client *, struct rpc_clnt *);
+extern void nfsd4_shutdown_callback(struct nfs4_client *);
 extern void nfs4_put_delegation(struct nfs4_delegation *dp);
 extern __be32 nfs4_make_rec_clidname(char *clidname, struct xdr_netobj *clname);
 extern void nfsd4_init_recdir(char *recdir_name);