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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>
This commit is contained in:
John Spray 2014-09-09 19:26:01 +01:00 committed by Sage Weil
parent a4483e8a42
commit dbd0c8bf79
1 changed files with 70 additions and 1 deletions
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71
fs/ceph/mds_client.c
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@ -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 @@ static struct ceph_msg *create_session_msg(u32 op, u64 seq)
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 @@ static int __open_session(struct ceph_mds_client *mdsc,
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);