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wip-9189: including client metadata when opening sessions #6

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wip-9189: including client metadata when opening sessions #6

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71 changes: 70 additions & 1 deletion fs/ceph/mds_client.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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"
Expand Down Expand Up @@ -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;
u8 *buf_off = NULL;
struct ceph_options *opt = mdsc->fsc->client->options;

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
buf_off = msg->front.iov_base + sizeof(*h);

// Number of entries in the map
*((u32*)buf_off) = cpu_to_le32(metadata_key_count);
buf_off += sizeof(u32);

// 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]);

*((u32*)buf_off) = cpu_to_le32(key_len);
buf_off += sizeof(u32);
memcpy(buf_off, metadata[i][0], key_len);
buf_off += key_len;
*((u32*)buf_off) = cpu_to_le32(val_len);
buf_off += sizeof(u32);
memcpy(buf_off, metadata[i][1], val_len);
buf_off += val_len;
}

return msg;
}

Expand All @@ -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);
Expand Down