ceph: send client metadata to MDS
Implement version 2 of CEPH_MSG_CLIENT_SESSION syntax,
which includes additional client metadata to allow
the MDS to report on clients by user-sensible names
like hostname.
Signed-off-by: John Spray <john.spray@redhat.com>
Reviewed-by: Yan, Zheng <zyan@redhat.com>
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 5edf206..5474feb 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -7,6 +7,7 @@
#include <linux/sched.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
+#include <linux/utsname.h>
#include "super.h"
#include "mds_client.h"
@@ -812,6 +813,74 @@
h = msg->front.iov_base;
h->op = cpu_to_le32(op);
h->seq = cpu_to_le64(seq);
+
+ return msg;
+}
+
+/*
+ * session message, specialization for CEPH_SESSION_REQUEST_OPEN
+ * to include additional client metadata fields.
+ */
+static struct ceph_msg *create_session_open_msg(struct ceph_mds_client *mdsc, u64 seq)
+{
+ struct ceph_msg *msg;
+ struct ceph_mds_session_head *h;
+ int i = -1;
+ int metadata_bytes = 0;
+ int metadata_key_count = 0;
+ struct ceph_options *opt = mdsc->fsc->client->options;
+ void *p;
+
+ const char* metadata[3][2] = {
+ {"hostname", utsname()->nodename},
+ {"entity_id", opt->name ? opt->name : ""},
+ {NULL, NULL}
+ };
+
+ /* Calculate serialized length of metadata */
+ metadata_bytes = 4; /* map length */
+ for (i = 0; metadata[i][0] != NULL; ++i) {
+ metadata_bytes += 8 + strlen(metadata[i][0]) +
+ strlen(metadata[i][1]);
+ metadata_key_count++;
+ }
+
+ /* Allocate the message */
+ msg = ceph_msg_new(CEPH_MSG_CLIENT_SESSION, sizeof(*h) + metadata_bytes,
+ GFP_NOFS, false);
+ if (!msg) {
+ pr_err("create_session_msg ENOMEM creating msg\n");
+ return NULL;
+ }
+ h = msg->front.iov_base;
+ h->op = cpu_to_le32(CEPH_SESSION_REQUEST_OPEN);
+ h->seq = cpu_to_le64(seq);
+
+ /*
+ * Serialize client metadata into waiting buffer space, using
+ * the format that userspace expects for map<string, string>
+ */
+ msg->hdr.version = 2; /* ClientSession messages with metadata are v2 */
+
+ /* The write pointer, following the session_head structure */
+ p = msg->front.iov_base + sizeof(*h);
+
+ /* Number of entries in the map */
+ ceph_encode_32(&p, metadata_key_count);
+
+ /* Two length-prefixed strings for each entry in the map */
+ for (i = 0; metadata[i][0] != NULL; ++i) {
+ size_t const key_len = strlen(metadata[i][0]);
+ size_t const val_len = strlen(metadata[i][1]);
+
+ ceph_encode_32(&p, key_len);
+ memcpy(p, metadata[i][0], key_len);
+ p += key_len;
+ ceph_encode_32(&p, val_len);
+ memcpy(p, metadata[i][1], val_len);
+ p += val_len;
+ }
+
return msg;
}
@@ -835,7 +904,7 @@
session->s_renew_requested = jiffies;
/* send connect message */
- msg = create_session_msg(CEPH_SESSION_REQUEST_OPEN, session->s_seq);
+ msg = create_session_open_msg(mdsc, session->s_seq);
if (!msg)
return -ENOMEM;
ceph_con_send(&session->s_con, msg);
