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, 3 insertions, 4 deletions

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 2f464fb26afc..d3f12dcc1696 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -207,7 +207,6 @@ alloc_init_deleg(struct nfs4_client *clp, struct nfs4_stateid *stp, struct svc_f
 {
         struct nfs4_delegation *dp;
         struct nfs4_file *fp = stp->st_file;
-        struct nfs4_cb_conn *conn = &stp->st_stateowner->so_client->cl_cb_conn;
 
         dprintk("NFSD alloc_init_deleg\n");
         /*
@@ -234,7 +233,6 @@ alloc_init_deleg(struct nfs4_client *clp, struct nfs4_stateid *stp, struct svc_f
         nfs4_file_get_access(fp, O_RDONLY);
         dp->dl_flock = NULL;
         dp->dl_type = type;
-        dp->dl_ident = conn->cb_ident;
         dp->dl_stateid.si_boot = boot_time;
         dp->dl_stateid.si_stateownerid = current_delegid++;
         dp->dl_stateid.si_fileid = 0;
@@ -875,7 +873,7 @@ expire_client(struct nfs4_client *clp)
                 sop = list_entry(clp->cl_openowners.next, struct nfs4_stateowner, so_perclient);
                 release_openowner(sop);
         }
-        nfsd4_set_callback_client(clp, NULL);
+        nfsd4_shutdown_callback(clp);
         if (clp->cl_cb_conn.cb_xprt)
                 svc_xprt_put(clp->cl_cb_conn.cb_xprt);
         list_del(&clp->cl_idhash);
@@ -978,6 +976,7 @@ static struct nfs4_client *create_client(struct xdr_netobj name, char *recdir,
         INIT_LIST_HEAD(&clp->cl_delegations);
         INIT_LIST_HEAD(&clp->cl_sessions);
         INIT_LIST_HEAD(&clp->cl_lru);
+        spin_lock_init(&clp->cl_lock);
         INIT_WORK(&clp->cl_cb_null.cb_work, nfsd4_do_callback_rpc);
         clp->cl_time = get_seconds();
         clear_bit(0, &clp->cl_cb_slot_busy);
@@ -1547,7 +1546,7 @@ nfsd4_destroy_session(struct svc_rqst *r,
 
         nfs4_lock_state();
         /* wait for callbacks */
-        nfsd4_set_callback_client(ses->se_client, NULL);
+        nfsd4_shutdown_callback(ses->se_client);
         nfs4_unlock_state();
         nfsd4_put_session(ses);
         status = nfs_ok;