[PATCH 08/10] nfsd4: add file to display list of client's opens

["J. Bruce Fields" <bfields@redhat.com>]

From: "J. Bruce Fields" <bfields@redhat.com>

Add a nfsd/clients/#/opens file to list some information about all the
opens held by the given client.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
---
 fs/nfsd/nfs4state.c | 100 +++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 98 insertions(+), 2 deletions(-)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 928705fc8ff5..829d1e5440d3 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -684,7 +684,8 @@ struct nfs4_stid *nfs4_alloc_stid(struct nfs4_client *cl, struct kmem_cache *sla
 
 	idr_preload(GFP_KERNEL);
 	spin_lock(&cl->cl_lock);
-	new_id = idr_alloc_cyclic(&cl->cl_stateids, stid, 0, 0, GFP_NOWAIT);
+	/* Reserving 0 for start of file in nfsdfs "opens" file: */
+	new_id = idr_alloc_cyclic(&cl->cl_stateids, stid, 1, 0, GFP_NOWAIT);
 	spin_unlock(&cl->cl_lock);
 	idr_preload_end();
 	if (new_id < 0)
@@ -2223,9 +2224,104 @@ static const struct file_operations client_info_fops = {
 	.release	= single_release,
 };
 
+static void *opens_start(struct seq_file *s, loff_t *pos)
+	__acquires(&clp->cl_lock)
+{
+	struct nfs4_client *clp = s->private;
+	unsigned long id = *pos;
+	void *ret;
+
+	spin_lock(&clp->cl_lock);
+	ret = idr_get_next_ul(&clp->cl_stateids, &id);
+	*pos = id;
+	return ret;
+}
+
+static void *opens_next(struct seq_file *s, void *v, loff_t *pos)
+{
+	struct nfs4_client *clp = s->private;
+	unsigned long id = *pos;
+	void *ret;
+
+	id = *pos;
+	id++;
+	ret = idr_get_next_ul(&clp->cl_stateids, &id);
+	*pos = id;
+	return ret;
+}
+
+static void opens_stop(struct seq_file *s, void *v)
+	__releases(&clp->cl_lock)
+{
+	struct nfs4_client *clp = s->private;
+
+	spin_unlock(&clp->cl_lock);
+}
+
+static int opens_show(struct seq_file *s, void *v)
+{
+	struct nfs4_stid *st = v;
+	struct nfs4_ol_stateid *os;
+	u64 stateid;
+
+	if (st->sc_type != NFS4_OPEN_STID)
+		return 0; /* XXX: or SEQ_SKIP? */
+	os = openlockstateid(st);
+	/* XXX: get info about file, etc., here */
+
+	memcpy(&stateid, &st->sc_stateid, sizeof(stateid));
+	seq_printf(s, "stateid: %llx\n", stateid);
+	return 0;
+}
+
+static struct seq_operations opens_seq_ops = {
+	.start = opens_start,
+	.next = opens_next,
+	.stop = opens_stop,
+	.show = opens_show
+};
+
+static int client_opens_open(struct inode *inode, struct file *file)
+{
+	struct nfsdfs_client *nc;
+	struct seq_file *s;
+	struct nfs4_client *clp;
+	int ret;
+
+	nc = get_nfsdfs_client(inode);
+	if (!nc)
+		return -ENXIO;
+	clp = container_of(nc, struct nfs4_client, cl_nfsdfs);
+
+	ret = seq_open(file, &opens_seq_ops);
+	if (ret)
+		return ret;
+	s = file->private_data;
+	s->private = clp;
+	return 0;
+}
+
+static int client_opens_release(struct inode *inode, struct file *file)
+{
+	struct seq_file *m = file->private_data;
+	struct nfs4_client *clp = m->private;
+
+	/* XXX: alternatively, we could get/drop in seq start/stop */
+	drop_client(clp);
+	return 0;
+}
+
+static const struct file_operations client_opens_fops = {
+	.open		= client_opens_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= client_opens_release,
+};
+
 static const struct tree_descr client_files[] = {
 	[0] = {"info", &client_info_fops, S_IRUSR},
-	[1] = {""},
+	[1] = {"open", &client_opens_fops, S_IRUSR},
+	[2] = {""},
 };
 
 static struct nfs4_client *create_client(struct xdr_netobj name,
-- 
2.20.1