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Commit dbd0c8bf authored by John Spray's avatar John Spray Committed by Sage Weil
Browse files

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: default avatarJohn Spray <john.spray@redhat.com>
Reviewed-by: default avatarYan, Zheng <zyan@redhat.com>
parent a4483e8a

fs/ceph/mds_client.c

+70 −1
Original line number Diff line number Diff line
@@ -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);