nfsd: handle legacy client tracking records sent by nfsdcld

The new nfsdcld will do a one-time "upgrade" where it searches for
records from nfsdcltrack and the legacy tracking during startup.
Legacy records will be prefixed with the string "hash:", which we need
to strip off before adding to the reclaim_str_hashtbl.  When legacy
records are encountered, set the new cn_has_legacy flag in the cld_net.
When this flag is set, if the search for a reclaim record based on the
client name string fails, then do a second search based on the hash of
the name string.

Note that if there are legacy records then the grace period will not
be lifted early via the tracking of RECLAIM_COMPLETEs.
Signed-off-by: Scott Mayhew <smayhew@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

fs/nfsd/nfs4recover.c

@@ -731,6 +731,7 @@ struct cld_net {
 	spinlock_t		 cn_lock;
 	struct list_head	 cn_list;
 	unsigned int		 cn_xid;
+	bool			 cn_has_legacy;
 };
 
 struct cld_upcall {
@@ -787,6 +788,7 @@ __cld_pipe_inprogress_downcall(const struct cld_msg __user *cmsg,
 	uint8_t cmd;
 	struct xdr_netobj name;
 	uint16_t namelen;
+	struct cld_net *cn = nn->cld_net;
 
 	if (get_user(cmd, &cmsg->cm_cmd)) {
 		dprintk("%s: error when copying cmd from userspace", __func__);
@@ -799,6 +801,11 @@ __cld_pipe_inprogress_downcall(const struct cld_msg __user *cmsg,
 		if (IS_ERR_OR_NULL(name.data))
 			return -EFAULT;
 		name.len = namelen;
+		if (name.len > 5 && memcmp(name.data, "hash:", 5) == 0) {
+			name.len = name.len - 5;
+			memmove(name.data, name.data + 5, name.len);
+			cn->cn_has_legacy = true;
+		}
 		if (!nfs4_client_to_reclaim(name, nn)) {
 			kfree(name.data);
 			return -EFAULT;
@@ -969,6 +976,7 @@ __nfsd4_init_cld_pipe(struct net *net)
 	}
 
 	cn->cn_pipe->dentry = dentry;
+	cn->cn_has_legacy = false;
 	nn->cld_net = cn;
 	return 0;
 
@@ -1171,6 +1179,10 @@ nfsd4_cld_check(struct nfs4_client *clp)
 {
 	struct nfs4_client_reclaim *crp;
 	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
+	struct cld_net *cn = nn->cld_net;
+	int status;
+	char dname[HEXDIR_LEN];
+	struct xdr_netobj name;
 
 	/* did we already find that this client is stable? */
 	if (test_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags))
@@ -1178,12 +1190,31 @@ nfsd4_cld_check(struct nfs4_client *clp)
 
 	/* look for it in the reclaim hashtable otherwise */
 	crp = nfsd4_find_reclaim_client(clp->cl_name, nn);
-	if (crp) {
-		crp->cr_clp = clp;
-		return 0;
-	}
+	if (crp)
+		goto found;
+
+	if (cn->cn_has_legacy) {
+		status = nfs4_make_rec_clidname(dname, &clp->cl_name);
+		if (status)
+			return -ENOENT;
+
+		name.data = kmemdup(dname, HEXDIR_LEN, GFP_KERNEL);
+		if (!name.data) {
+			dprintk("%s: failed to allocate memory for name.data!\n",
+				__func__);
+			return -ENOENT;
+		}
+		name.len = HEXDIR_LEN;
+		crp = nfsd4_find_reclaim_client(name, nn);
+		kfree(name.data);
+		if (crp)
+			goto found;
 
+	}
 	return -ENOENT;
+found:
+	crp->cr_clp = clp;
+	return 0;
 }
 
 static int