linux/fs/ceph/mon_client.c

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#include "ceph_debug.h"
#include <linux/types.h>
#include <linux/random.h>
#include <linux/sched.h>
#include "mon_client.h"
#include "super.h"
#include "decode.h"
/*
* Interact with Ceph monitor cluster. Handle requests for new map
* versions, and periodically resend as needed. Also implement
* statfs() and umount().
*
* A small cluster of Ceph "monitors" are responsible for managing critical
* cluster configuration and state information. An odd number (e.g., 3, 5)
* of cmon daemons use a modified version of the Paxos part-time parliament
* algorithm to manage the MDS map (mds cluster membership), OSD map, and
* list of clients who have mounted the file system.
*
* We maintain an open, active session with a monitor at all times in order to
* receive timely MDSMap updates. We periodically send a keepalive byte on the
* TCP socket to ensure we detect a failure. If the connection does break, we
* randomly hunt for a new monitor. Once the connection is reestablished, we
* resend any outstanding requests.
*/
const static struct ceph_connection_operations mon_con_ops;
/*
* Decode a monmap blob (e.g., during mount).
*/
struct ceph_monmap *ceph_monmap_decode(void *p, void *end)
{
struct ceph_monmap *m = NULL;
int i, err = -EINVAL;
struct ceph_fsid fsid;
u32 epoch, num_mon;
u16 version;
dout("monmap_decode %p %p len %d\n", p, end, (int)(end-p));
ceph_decode_16_safe(&p, end, version, bad);
ceph_decode_need(&p, end, sizeof(fsid) + 2*sizeof(u32), bad);
ceph_decode_copy(&p, &fsid, sizeof(fsid));
ceph_decode_32(&p, epoch);
ceph_decode_32(&p, num_mon);
ceph_decode_need(&p, end, num_mon*sizeof(m->mon_inst[0]), bad);
if (num_mon >= CEPH_MAX_MON)
goto bad;
m = kmalloc(sizeof(*m) + sizeof(m->mon_inst[0])*num_mon, GFP_NOFS);
if (m == NULL)
return ERR_PTR(-ENOMEM);
m->fsid = fsid;
m->epoch = epoch;
m->num_mon = num_mon;
ceph_decode_copy(&p, m->mon_inst, num_mon*sizeof(m->mon_inst[0]));
if (p != end)
goto bad;
dout("monmap_decode epoch %d, num_mon %d\n", m->epoch,
m->num_mon);
for (i = 0; i < m->num_mon; i++)
dout("monmap_decode mon%d is %s\n", i,
pr_addr(&m->mon_inst[i].addr.in_addr));
return m;
bad:
dout("monmap_decode failed with %d\n", err);
kfree(m);
return ERR_PTR(err);
}
/*
* return true if *addr is included in the monmap.
*/
int ceph_monmap_contains(struct ceph_monmap *m, struct ceph_entity_addr *addr)
{
int i;
for (i = 0; i < m->num_mon; i++)
if (ceph_entity_addr_equal(addr, &m->mon_inst[i].addr))
return 1;
return 0;
}
/*
* Close monitor session, if any.
*/
static void __close_session(struct ceph_mon_client *monc)
{
if (monc->con) {
dout("__close_session closing mon%d\n", monc->cur_mon);
ceph_con_close(monc->con);
monc->cur_mon = -1;
}
}
/*
* Open a session with a (new) monitor.
*/
static int __open_session(struct ceph_mon_client *monc)
{
char r;
if (monc->cur_mon < 0) {
get_random_bytes(&r, 1);
monc->cur_mon = r % monc->monmap->num_mon;
dout("open_session num=%d r=%d -> mon%d\n",
monc->monmap->num_mon, r, monc->cur_mon);
monc->sub_sent = 0;
monc->sub_renew_after = jiffies; /* i.e., expired */
monc->want_next_osdmap = !!monc->want_next_osdmap;
dout("open_session mon%d opening\n", monc->cur_mon);
monc->con->peer_name.type = CEPH_ENTITY_TYPE_MON;
monc->con->peer_name.num = cpu_to_le64(monc->cur_mon);
ceph_con_open(monc->con,
&monc->monmap->mon_inst[monc->cur_mon].addr);
} else {
dout("open_session mon%d already open\n", monc->cur_mon);
}
return 0;
}
static bool __sub_expired(struct ceph_mon_client *monc)
{
return time_after_eq(jiffies, monc->sub_renew_after);
}
/*
* Reschedule delayed work timer.
*/
static void __schedule_delayed(struct ceph_mon_client *monc)
{
unsigned delay;
if (monc->cur_mon < 0 || monc->want_mount || __sub_expired(monc))
delay = 10 * HZ;
else
delay = 20 * HZ;
dout("__schedule_delayed after %u\n", delay);
schedule_delayed_work(&monc->delayed_work, delay);
}
/*
* Send subscribe request for mdsmap and/or osdmap.
*/
static void __send_subscribe(struct ceph_mon_client *monc)
{
dout("__send_subscribe sub_sent=%u exp=%u want_osd=%d\n",
(unsigned)monc->sub_sent, __sub_expired(monc),
monc->want_next_osdmap);
if ((__sub_expired(monc) && !monc->sub_sent) ||
monc->want_next_osdmap == 1) {
struct ceph_msg *msg;
struct ceph_mon_subscribe_item *i;
void *p, *end;
msg = ceph_msg_new(CEPH_MSG_MON_SUBSCRIBE, 64, 0, 0, NULL);
if (!msg)
return;
p = msg->front.iov_base;
end = p + msg->front.iov_len;
dout("__send_subscribe to 'mdsmap' %u+\n",
(unsigned)monc->have_mdsmap);
if (monc->want_next_osdmap) {
dout("__send_subscribe to 'osdmap' %u\n",
(unsigned)monc->have_osdmap);
ceph_encode_32(&p, 2);
ceph_encode_string(&p, end, "osdmap", 6);
i = p;
i->have = cpu_to_le64(monc->have_osdmap);
i->onetime = 1;
p += sizeof(*i);
monc->want_next_osdmap = 2; /* requested */
} else {
ceph_encode_32(&p, 1);
}
ceph_encode_string(&p, end, "mdsmap", 6);
i = p;
i->have = cpu_to_le64(monc->have_mdsmap);
i->onetime = 0;
p += sizeof(*i);
msg->front.iov_len = p - msg->front.iov_base;
msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
ceph_con_send(monc->con, msg);
monc->sub_sent = jiffies | 1; /* never 0 */
}
}
static void handle_subscribe_ack(struct ceph_mon_client *monc,
struct ceph_msg *msg)
{
unsigned seconds;
void *p = msg->front.iov_base;
void *end = p + msg->front.iov_len;
ceph_decode_32_safe(&p, end, seconds, bad);
mutex_lock(&monc->mutex);
if (monc->hunting) {
pr_info("mon%d %s session established\n",
monc->cur_mon, pr_addr(&monc->con->peer_addr.in_addr));
monc->hunting = false;
}
dout("handle_subscribe_ack after %d seconds\n", seconds);
monc->sub_renew_after = monc->sub_sent + seconds*HZ - 1;
monc->sub_sent = 0;
mutex_unlock(&monc->mutex);
return;
bad:
pr_err("got corrupt subscribe-ack msg\n");
}
/*
* Keep track of which maps we have
*/
int ceph_monc_got_mdsmap(struct ceph_mon_client *monc, u32 got)
{
mutex_lock(&monc->mutex);
monc->have_mdsmap = got;
mutex_unlock(&monc->mutex);
return 0;
}
int ceph_monc_got_osdmap(struct ceph_mon_client *monc, u32 got)
{
mutex_lock(&monc->mutex);
monc->have_osdmap = got;
monc->want_next_osdmap = 0;
mutex_unlock(&monc->mutex);
return 0;
}
/*
* Register interest in the next osdmap
*/
void ceph_monc_request_next_osdmap(struct ceph_mon_client *monc)
{
dout("request_next_osdmap have %u\n", monc->have_osdmap);
mutex_lock(&monc->mutex);
if (!monc->want_next_osdmap)
monc->want_next_osdmap = 1;
if (monc->want_next_osdmap < 2)
__send_subscribe(monc);
mutex_unlock(&monc->mutex);
}
/*
* mount
*/
static void __request_mount(struct ceph_mon_client *monc)
{
struct ceph_msg *msg;
struct ceph_client_mount *h;
int err;
dout("__request_mount\n");
err = __open_session(monc);
if (err)
return;
msg = ceph_msg_new(CEPH_MSG_CLIENT_MOUNT, sizeof(*h), 0, 0, NULL);
if (IS_ERR(msg))
return;
h = msg->front.iov_base;
h->have_version = 0;
ceph_con_send(monc->con, msg);
}
int ceph_monc_request_mount(struct ceph_mon_client *monc)
{
if (!monc->con) {
monc->con = kmalloc(sizeof(*monc->con), GFP_KERNEL);
if (!monc->con)
return -ENOMEM;
ceph_con_init(monc->client->msgr, monc->con);
monc->con->private = monc;
monc->con->ops = &mon_con_ops;
}
mutex_lock(&monc->mutex);
__request_mount(monc);
__schedule_delayed(monc);
mutex_unlock(&monc->mutex);
return 0;
}
/*
* The monitor responds with mount ack indicate mount success. The
* included client ticket allows the client to talk to MDSs and OSDs.
*/
static void handle_mount_ack(struct ceph_mon_client *monc, struct ceph_msg *msg)
{
struct ceph_client *client = monc->client;
struct ceph_monmap *monmap = NULL, *old = monc->monmap;
void *p, *end;
s32 result;
u32 len;
s64 cnum;
int err = -EINVAL;
if (client->whoami >= 0) {
dout("handle_mount_ack - already mounted\n");
return;
}
mutex_lock(&monc->mutex);
dout("handle_mount_ack\n");
p = msg->front.iov_base;
end = p + msg->front.iov_len;
ceph_decode_64_safe(&p, end, cnum, bad);
ceph_decode_32_safe(&p, end, result, bad);
ceph_decode_32_safe(&p, end, len, bad);
if (result) {
pr_err("mount denied: %.*s (%d)\n", len, (char *)p,
result);
err = result;
goto out;
}
p += len;
ceph_decode_32_safe(&p, end, len, bad);
ceph_decode_need(&p, end, len, bad);
monmap = ceph_monmap_decode(p, p + len);
if (IS_ERR(monmap)) {
pr_err("problem decoding monmap, %d\n",
(int)PTR_ERR(monmap));
err = -EINVAL;
goto out;
}
p += len;
client->monc.monmap = monmap;
kfree(old);
client->signed_ticket = NULL;
client->signed_ticket_len = 0;
monc->want_mount = false;
client->whoami = cnum;
client->msgr->inst.name.type = CEPH_ENTITY_TYPE_CLIENT;
client->msgr->inst.name.num = cpu_to_le64(cnum);
pr_info("client%lld fsid " FSID_FORMAT "\n",
client->whoami, PR_FSID(&client->monc.monmap->fsid));
ceph_debugfs_client_init(client);
__send_subscribe(monc);
err = 0;
goto out;
bad:
pr_err("error decoding mount_ack message\n");
out:
client->mount_err = err;
mutex_unlock(&monc->mutex);
wake_up(&client->mount_wq);
}
/*
* statfs
*/
static void handle_statfs_reply(struct ceph_mon_client *monc,
struct ceph_msg *msg)
{
struct ceph_mon_statfs_request *req;
struct ceph_mon_statfs_reply *reply = msg->front.iov_base;
u64 tid;
if (msg->front.iov_len != sizeof(*reply))
goto bad;
tid = le64_to_cpu(reply->tid);
dout("handle_statfs_reply %p tid %llu\n", msg, tid);
mutex_lock(&monc->mutex);
req = radix_tree_lookup(&monc->statfs_request_tree, tid);
if (req) {
*req->buf = reply->st;
req->result = 0;
}
mutex_unlock(&monc->mutex);
if (req)
complete(&req->completion);
return;
bad:
pr_err("corrupt statfs reply, no tid\n");
}
/*
* (re)send a statfs request
*/
static int send_statfs(struct ceph_mon_client *monc,
struct ceph_mon_statfs_request *req)
{
struct ceph_msg *msg;
struct ceph_mon_statfs *h;
int err;
dout("send_statfs tid %llu\n", req->tid);
err = __open_session(monc);
if (err)
return err;
msg = ceph_msg_new(CEPH_MSG_STATFS, sizeof(*h), 0, 0, NULL);
if (IS_ERR(msg))
return PTR_ERR(msg);
req->request = msg;
h = msg->front.iov_base;
h->have_version = 0;
h->fsid = monc->monmap->fsid;
h->tid = cpu_to_le64(req->tid);
ceph_con_send(monc->con, msg);
return 0;
}
/*
* Do a synchronous statfs().
*/
int ceph_monc_do_statfs(struct ceph_mon_client *monc, struct ceph_statfs *buf)
{
struct ceph_mon_statfs_request req;
int err;
req.buf = buf;
init_completion(&req.completion);
/* allocate memory for reply */
err = ceph_msgpool_resv(&monc->msgpool_statfs_reply, 1);
if (err)
return err;
/* register request */
mutex_lock(&monc->mutex);
req.tid = ++monc->last_tid;
req.last_attempt = jiffies;
req.delay = BASE_DELAY_INTERVAL;
if (radix_tree_insert(&monc->statfs_request_tree, req.tid, &req) < 0) {
mutex_unlock(&monc->mutex);
pr_err("ENOMEM in do_statfs\n");
return -ENOMEM;
}
monc->num_statfs_requests++;
mutex_unlock(&monc->mutex);
/* send request and wait */
err = send_statfs(monc, &req);
if (!err)
err = wait_for_completion_interruptible(&req.completion);
mutex_lock(&monc->mutex);
radix_tree_delete(&monc->statfs_request_tree, req.tid);
monc->num_statfs_requests--;
ceph_msgpool_resv(&monc->msgpool_statfs_reply, -1);
mutex_unlock(&monc->mutex);
if (!err)
err = req.result;
return err;
}
/*
* Resend pending statfs requests.
*/
static void __resend_statfs(struct ceph_mon_client *monc)
{
u64 next_tid = 0;
int got;
int did = 0;
struct ceph_mon_statfs_request *req;
while (1) {
got = radix_tree_gang_lookup(&monc->statfs_request_tree,
(void **)&req,
next_tid, 1);
if (got == 0)
break;
did++;
next_tid = req->tid + 1;
send_statfs(monc, req);
}
}
/*
* Delayed work. If we haven't mounted yet, retry. Otherwise,
* renew/retry subscription as needed (in case it is timing out, or we
* got an ENOMEM). And keep the monitor connection alive.
*/
static void delayed_work(struct work_struct *work)
{
struct ceph_mon_client *monc =
container_of(work, struct ceph_mon_client, delayed_work.work);
dout("monc delayed_work\n");
mutex_lock(&monc->mutex);
if (monc->want_mount) {
__request_mount(monc);
} else {
if (__sub_expired(monc)) {
__close_session(monc);
__open_session(monc); /* continue hunting */
} else {
ceph_con_keepalive(monc->con);
}
}
__send_subscribe(monc);
__schedule_delayed(monc);
mutex_unlock(&monc->mutex);
}
int ceph_monc_init(struct ceph_mon_client *monc, struct ceph_client *cl)
{
int err = 0;
dout("init\n");
memset(monc, 0, sizeof(*monc));
monc->client = cl;
monc->monmap = NULL;
mutex_init(&monc->mutex);
monc->con = NULL;
/* msg pools */
err = ceph_msgpool_init(&monc->msgpool_mount_ack, 4096, 1, false);
if (err < 0)
goto out;
err = ceph_msgpool_init(&monc->msgpool_subscribe_ack, 8, 1, false);
if (err < 0)
goto out;
err = ceph_msgpool_init(&monc->msgpool_statfs_reply,
sizeof(struct ceph_mon_statfs_reply), 0, false);
if (err < 0)
goto out;
monc->cur_mon = -1;
monc->hunting = false; /* not really */
monc->sub_renew_after = jiffies;
monc->sub_sent = 0;
INIT_DELAYED_WORK(&monc->delayed_work, delayed_work);
INIT_RADIX_TREE(&monc->statfs_request_tree, GFP_NOFS);
monc->num_statfs_requests = 0;
monc->last_tid = 0;
monc->have_mdsmap = 0;
monc->have_osdmap = 0;
monc->want_next_osdmap = 1;
monc->want_mount = true;
out:
return err;
}
void ceph_monc_stop(struct ceph_mon_client *monc)
{
dout("stop\n");
cancel_delayed_work_sync(&monc->delayed_work);
mutex_lock(&monc->mutex);
__close_session(monc);
if (monc->con) {
monc->con->private = NULL;
monc->con->ops->put(monc->con);
monc->con = NULL;
}
mutex_unlock(&monc->mutex);
ceph_msgpool_destroy(&monc->msgpool_mount_ack);
ceph_msgpool_destroy(&monc->msgpool_subscribe_ack);
ceph_msgpool_destroy(&monc->msgpool_statfs_reply);
kfree(monc->monmap);
}
/*
* handle incoming message
*/
static void dispatch(struct ceph_connection *con, struct ceph_msg *msg)
{
struct ceph_mon_client *monc = con->private;
int type = le16_to_cpu(msg->hdr.type);
if (!monc)
return;
switch (type) {
case CEPH_MSG_CLIENT_MOUNT_ACK:
handle_mount_ack(monc, msg);
break;
case CEPH_MSG_MON_SUBSCRIBE_ACK:
handle_subscribe_ack(monc, msg);
break;
case CEPH_MSG_STATFS_REPLY:
handle_statfs_reply(monc, msg);
break;
case CEPH_MSG_MDS_MAP:
ceph_mdsc_handle_map(&monc->client->mdsc, msg);
break;
case CEPH_MSG_OSD_MAP:
ceph_osdc_handle_map(&monc->client->osdc, msg);
break;
default:
pr_err("received unknown message type %d %s\n", type,
ceph_msg_type_name(type));
}
ceph_msg_put(msg);
}
/*
* Allocate memory for incoming message
*/
static struct ceph_msg *mon_alloc_msg(struct ceph_connection *con,
struct ceph_msg_header *hdr)
{
struct ceph_mon_client *monc = con->private;
int type = le16_to_cpu(hdr->type);
switch (type) {
case CEPH_MSG_CLIENT_MOUNT_ACK:
return ceph_msgpool_get(&monc->msgpool_mount_ack);
case CEPH_MSG_MON_SUBSCRIBE_ACK:
return ceph_msgpool_get(&monc->msgpool_subscribe_ack);
case CEPH_MSG_STATFS_REPLY:
return ceph_msgpool_get(&monc->msgpool_statfs_reply);
}
return ceph_alloc_msg(con, hdr);
}
/*
* If the monitor connection resets, pick a new monitor and resubmit
* any pending requests.
*/
static void mon_fault(struct ceph_connection *con)
{
struct ceph_mon_client *monc = con->private;
if (!monc)
return;
dout("mon_fault\n");
mutex_lock(&monc->mutex);
if (!con->private)
goto out;
if (monc->con && !monc->hunting)
pr_info("mon%d %s session lost, "
"hunting for new mon\n", monc->cur_mon,
pr_addr(&monc->con->peer_addr.in_addr));
__close_session(monc);
if (!monc->hunting) {
/* start hunting */
monc->hunting = true;
if (__open_session(monc) == 0) {
__send_subscribe(monc);
__resend_statfs(monc);
}
} else {
/* already hunting, let's wait a bit */
__schedule_delayed(monc);
}
out:
mutex_unlock(&monc->mutex);
}
const static struct ceph_connection_operations mon_con_ops = {
.get = ceph_con_get,
.put = ceph_con_put,
.dispatch = dispatch,
.fault = mon_fault,
.alloc_msg = mon_alloc_msg,
.alloc_middle = ceph_alloc_middle,
};