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    Subject[PATCH 13/21] ceph: monitor client
    Date
    The monitor cluster is responsible for managing cluster membership
    and state. The monitor client handles what minimal interaction
    the Ceph client has with it: checking for updated versions of the
    MDS and OSD maps, getting statfs() information, and unmounting.

    Signed-off-by: Sage Weil <sage@newdream.net>
    ---
    fs/ceph/mon_client.c | 694 ++++++++++++++++++++++++++++++++++++++++++++++++++
    fs/ceph/mon_client.h | 109 ++++++++
    2 files changed, 803 insertions(+), 0 deletions(-)
    create mode 100644 fs/ceph/mon_client.c
    create mode 100644 fs/ceph/mon_client.h

    diff --git a/fs/ceph/mon_client.c b/fs/ceph/mon_client.c
    new file mode 100644
    index 0000000..2558986
    --- /dev/null
    +++ b/fs/ceph/mon_client.c
    @@ -0,0 +1,694 @@
    +
    +#include <linux/types.h>
    +#include <linux/random.h>
    +#include <linux/sched.h>
    +#include "mon_client.h"
    +
    +#include "ceph_debug.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 %u.%u.%u.%u:%u\n", i,
    + IPQUADPORT(m->mon_inst[i].addr.ipaddr));
    + 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("ceph mon%d %u.%u.%u.%u:%u session established\n",
    + monc->cur_mon, IPQUADPORT(monc->con->peer_addr.ipaddr));
    + 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("ceph 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("ceph 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("ceph 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("ceph 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("ceph 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("ceph 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("ceph 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("ceph 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("ceph mon%d %u.%u.%u.%u:%u session lost, "
    + "hunting for new mon\n", monc->cur_mon,
    + IPQUADPORT(monc->con->peer_addr.ipaddr));
    +
    + __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,
    +};
    diff --git a/fs/ceph/mon_client.h b/fs/ceph/mon_client.h
    new file mode 100644
    index 0000000..5258c56
    --- /dev/null
    +++ b/fs/ceph/mon_client.h
    @@ -0,0 +1,109 @@
    +#ifndef _FS_CEPH_MON_CLIENT_H
    +#define _FS_CEPH_MON_CLIENT_H
    +
    +#include <linux/completion.h>
    +#include <linux/radix-tree.h>
    +
    +#include "messenger.h"
    +#include "msgpool.h"
    +
    +struct ceph_client;
    +struct ceph_mount_args;
    +
    +/*
    + * The monitor map enumerates the set of all monitors.
    + */
    +struct ceph_monmap {
    + struct ceph_fsid fsid;
    + u32 epoch;
    + u32 num_mon;
    + struct ceph_entity_inst mon_inst[0];
    +};
    +
    +struct ceph_mon_client;
    +struct ceph_mon_statfs_request;
    +
    +
    +/*
    + * Generic mechanism for resending monitor requests.
    + */
    +typedef void (*ceph_monc_request_func_t)(struct ceph_mon_client *monc,
    + int newmon);
    +
    +/* a pending monitor request */
    +struct ceph_mon_request {
    + struct ceph_mon_client *monc;
    + struct delayed_work delayed_work;
    + unsigned long delay;
    + ceph_monc_request_func_t do_request;
    +};
    +
    +/*
    + * statfs() is done a bit differently because we need to get data back
    + * to the caller
    + */
    +struct ceph_mon_statfs_request {
    + u64 tid;
    + int result;
    + struct ceph_statfs *buf;
    + struct completion completion;
    + unsigned long last_attempt, delay; /* jiffies */
    + struct ceph_msg *request; /* original request */
    +};
    +
    +struct ceph_mon_client {
    + struct ceph_client *client;
    + struct ceph_monmap *monmap;
    +
    + struct mutex mutex;
    + struct delayed_work delayed_work;
    +
    + bool hunting;
    + int cur_mon; /* last monitor i contacted */
    + unsigned long sub_sent, sub_renew_after;
    + struct ceph_connection *con;
    +
    + /* msg pools */
    + struct ceph_msgpool msgpool_mount_ack;
    + struct ceph_msgpool msgpool_subscribe_ack;
    + struct ceph_msgpool msgpool_statfs_reply;
    +
    + /* pending statfs requests */
    + struct radix_tree_root statfs_request_tree;
    + int num_statfs_requests;
    + u64 last_tid;
    +
    + /* mds/osd map or mount requests */
    + bool want_mount;
    + int want_next_osdmap; /* 1 = want, 2 = want+asked */
    + u32 have_osdmap, have_mdsmap;
    +
    + struct dentry *debugfs_file;
    +};
    +
    +extern struct ceph_monmap *ceph_monmap_decode(void *p, void *end);
    +extern int ceph_monmap_contains(struct ceph_monmap *m,
    + struct ceph_entity_addr *addr);
    +
    +extern int ceph_monc_init(struct ceph_mon_client *monc, struct ceph_client *cl);
    +extern void ceph_monc_stop(struct ceph_mon_client *monc);
    +
    +/*
    + * The model here is to indicate that we need a new map of at least
    + * epoch @want, and also call in when we receive a map. We will
    + * periodically rerequest the map from the monitor cluster until we
    + * get what we want.
    + */
    +extern int ceph_monc_got_mdsmap(struct ceph_mon_client *monc, u32 have);
    +extern int ceph_monc_got_osdmap(struct ceph_mon_client *monc, u32 have);
    +
    +extern void ceph_monc_request_next_osdmap(struct ceph_mon_client *monc);
    +
    +extern int ceph_monc_request_mount(struct ceph_mon_client *monc);
    +
    +extern int ceph_monc_do_statfs(struct ceph_mon_client *monc,
    + struct ceph_statfs *buf);
    +
    +
    +
    +#endif
    --
    1.5.6.5


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