ceph: OSD client

[safe/jmp/linux-2.6] / fs / ceph / osd_client.c

#include "ceph_debug.h"

#include <linux/err.h>
#include <linux/highmem.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/slab.h>
#include <linux/uaccess.h>

#include "super.h"
#include "osd_client.h"
#include "messenger.h"
#include "decode.h"

const static struct ceph_connection_operations osd_con_ops;

static void kick_requests(struct ceph_osd_client *osdc, struct ceph_osd *osd);

/*
 * Implement client access to distributed object storage cluster.
 *
 * All data objects are stored within a cluster/cloud of OSDs, or
 * "object storage devices."  (Note that Ceph OSDs have _nothing_ to
 * do with the T10 OSD extensions to SCSI.)  Ceph OSDs are simply
 * remote daemons serving up and coordinating consistent and safe
 * access to storage.
 *
 * Cluster membership and the mapping of data objects onto storage devices
 * are described by the osd map.
 *
 * We keep track of pending OSD requests (read, write), resubmit
 * requests to different OSDs when the cluster topology/data layout
 * change, or retry the affected requests when the communications
 * channel with an OSD is reset.
 */

/*
 * calculate the mapping of a file extent onto an object, and fill out the
 * request accordingly.  shorten extent as necessary if it crosses an
 * object boundary.
 *
 * fill osd op in request message.
 */
static void calc_layout(struct ceph_osd_client *osdc,
                        struct ceph_vino vino, struct ceph_file_layout *layout,
                        u64 off, u64 *plen,
                        struct ceph_osd_request *req)
{
        struct ceph_osd_request_head *reqhead = req->r_request->front.iov_base;
        struct ceph_osd_op *op = (void *)(reqhead + 1);
        u64 orig_len = *plen;
        u64 objoff, objlen;    /* extent in object */
        u64 bno;

        reqhead->snapid = cpu_to_le64(vino.snap);

        /* object extent? */
        ceph_calc_file_object_mapping(layout, off, plen, &bno,
                                      &objoff, &objlen);
        if (*plen < orig_len)
                dout(" skipping last %llu, final file extent %llu~%llu\n",
                     orig_len - *plen, off, *plen);

        sprintf(req->r_oid, "%llx.%08llx", vino.ino, bno);
        req->r_oid_len = strlen(req->r_oid);

        op->extent.offset = cpu_to_le64(objoff);
        op->extent.length = cpu_to_le64(objlen);
        req->r_num_pages = calc_pages_for(off, *plen);

        dout("calc_layout %s (%d) %llu~%llu (%d pages)\n",
             req->r_oid, req->r_oid_len, objoff, objlen, req->r_num_pages);
}


/*
 * requests
 */
void ceph_osdc_put_request(struct ceph_osd_request *req)
{
        dout("osdc put_request %p %d -> %d\n", req, atomic_read(&req->r_ref),
             atomic_read(&req->r_ref)-1);
        BUG_ON(atomic_read(&req->r_ref) <= 0);
        if (atomic_dec_and_test(&req->r_ref)) {
                if (req->r_request)
                        ceph_msg_put(req->r_request);
                if (req->r_reply)
                        ceph_msg_put(req->r_reply);
                if (req->r_own_pages)
                        ceph_release_page_vector(req->r_pages,
                                                 req->r_num_pages);
                ceph_put_snap_context(req->r_snapc);
                if (req->r_mempool)
                        mempool_free(req, req->r_osdc->req_mempool);
                else
                        kfree(req);
        }
}

/*
 * build new request AND message, calculate layout, and adjust file
 * extent as needed.
 *
 * if the file was recently truncated, we include information about its
 * old and new size so that the object can be updated appropriately.  (we
 * avoid synchronously deleting truncated objects because it's slow.)
 *
 * if @do_sync, include a 'startsync' command so that the osd will flush
 * data quickly.
 */
struct ceph_osd_request *ceph_osdc_new_request(struct ceph_osd_client *osdc,
                                               struct ceph_file_layout *layout,
                                               struct ceph_vino vino,
                                               u64 off, u64 *plen,
                                               int opcode, int flags,
                                               struct ceph_snap_context *snapc,
                                               int do_sync,
                                               u32 truncate_seq,
                                               u64 truncate_size,
                                               struct timespec *mtime,
                                               bool use_mempool, int num_reply)
{
        struct ceph_osd_request *req;
        struct ceph_msg *msg;
        struct ceph_osd_request_head *head;
        struct ceph_osd_op *op;
        void *p;
        int do_trunc = truncate_seq && (off + *plen > truncate_size);
        int num_op = 1 + do_sync + do_trunc;
        size_t msg_size = sizeof(*head) + num_op*sizeof(*op);
        int err, i;
        u64 prevofs;

        if (use_mempool) {
                req = mempool_alloc(osdc->req_mempool, GFP_NOFS);
                memset(req, 0, sizeof(*req));
        } else {
                req = kzalloc(sizeof(*req), GFP_NOFS);
        }
        if (req == NULL)
                return ERR_PTR(-ENOMEM);

        err = ceph_msgpool_resv(&osdc->msgpool_op_reply, num_reply);
        if (err) {
                ceph_osdc_put_request(req);
                return ERR_PTR(-ENOMEM);
        }

        req->r_osdc = osdc;
        req->r_mempool = use_mempool;
        atomic_set(&req->r_ref, 1);
        init_completion(&req->r_completion);
        init_completion(&req->r_safe_completion);
        INIT_LIST_HEAD(&req->r_unsafe_item);
        req->r_flags = flags;

        WARN_ON((flags & (CEPH_OSD_FLAG_READ|CEPH_OSD_FLAG_WRITE)) == 0);

        /* create message; allow space for oid */
        msg_size += 40;
        if (snapc)
                msg_size += sizeof(u64) * snapc->num_snaps;
        if (use_mempool)
                msg = ceph_msgpool_get(&osdc->msgpool_op);
        else
                msg = ceph_msg_new(CEPH_MSG_OSD_OP, msg_size, 0, 0, NULL);
        if (IS_ERR(msg)) {
                ceph_msgpool_resv(&osdc->msgpool_op_reply, num_reply);
                ceph_osdc_put_request(req);
                return ERR_PTR(PTR_ERR(msg));
        }
        msg->hdr.type = cpu_to_le16(CEPH_MSG_OSD_OP);
        memset(msg->front.iov_base, 0, msg->front.iov_len);
        head = msg->front.iov_base;
        op = (void *)(head + 1);
        p = (void *)(op + num_op);

        req->r_request = msg;
        req->r_snapc = ceph_get_snap_context(snapc);

        head->client_inc = cpu_to_le32(1); /* always, for now. */
        head->flags = cpu_to_le32(flags);
        if (flags & CEPH_OSD_FLAG_WRITE)
                ceph_encode_timespec(&head->mtime, mtime);
        head->num_ops = cpu_to_le16(num_op);
        op->op = cpu_to_le16(opcode);

        /* calculate max write size */
        calc_layout(osdc, vino, layout, off, plen, req);
        req->r_file_layout = *layout;  /* keep a copy */

        if (flags & CEPH_OSD_FLAG_WRITE) {
                req->r_request->hdr.data_off = cpu_to_le16(off);
                req->r_request->hdr.data_len = cpu_to_le32(*plen);
                op->payload_len = cpu_to_le32(*plen);
        }

        /* fill in oid */
        head->object_len = cpu_to_le32(req->r_oid_len);
        memcpy(p, req->r_oid, req->r_oid_len);
        p += req->r_oid_len;

        /* additional ops */
        if (do_trunc) {
                op++;
                op->op = cpu_to_le16(opcode == CEPH_OSD_OP_READ ?
                             CEPH_OSD_OP_MASKTRUNC : CEPH_OSD_OP_SETTRUNC);
                op->trunc.truncate_seq = cpu_to_le32(truncate_seq);
                prevofs = le64_to_cpu((op-1)->extent.offset);
                op->trunc.truncate_size = cpu_to_le64(truncate_size -
                                                      (off-prevofs));
        }
        if (do_sync) {
                op++;
                op->op = cpu_to_le16(CEPH_OSD_OP_STARTSYNC);
        }
        if (snapc) {
                head->snap_seq = cpu_to_le64(snapc->seq);
                head->num_snaps = cpu_to_le32(snapc->num_snaps);
                for (i = 0; i < snapc->num_snaps; i++) {
                        put_unaligned_le64(snapc->snaps[i], p);
                        p += sizeof(u64);
                }
        }

        BUG_ON(p > msg->front.iov_base + msg->front.iov_len);
        return req;
}

/*
 * We keep osd requests in an rbtree, sorted by ->r_tid.
 */
static void __insert_request(struct ceph_osd_client *osdc,
                             struct ceph_osd_request *new)
{
        struct rb_node **p = &osdc->requests.rb_node;
        struct rb_node *parent = NULL;
        struct ceph_osd_request *req = NULL;

        while (*p) {
                parent = *p;
                req = rb_entry(parent, struct ceph_osd_request, r_node);
                if (new->r_tid < req->r_tid)
                        p = &(*p)->rb_left;
                else if (new->r_tid > req->r_tid)
                        p = &(*p)->rb_right;
                else
                        BUG();
        }

        rb_link_node(&new->r_node, parent, p);
        rb_insert_color(&new->r_node, &osdc->requests);
}

static struct ceph_osd_request *__lookup_request(struct ceph_osd_client *osdc,
                                                 u64 tid)
{
        struct ceph_osd_request *req;
        struct rb_node *n = osdc->requests.rb_node;

        while (n) {
                req = rb_entry(n, struct ceph_osd_request, r_node);
                if (tid < req->r_tid)
                        n = n->rb_left;
                else if (tid > req->r_tid)
                        n = n->rb_right;
                else
                        return req;
        }
        return NULL;
}

static struct ceph_osd_request *
__lookup_request_ge(struct ceph_osd_client *osdc,
                    u64 tid)
{
        struct ceph_osd_request *req;
        struct rb_node *n = osdc->requests.rb_node;

        while (n) {
                req = rb_entry(n, struct ceph_osd_request, r_node);
                if (tid < req->r_tid) {
                        if (!n->rb_left)
                                return req;
                        n = n->rb_left;
                } else if (tid > req->r_tid) {
                        n = n->rb_right;
                } else {
                        return req;
                }
        }
        return NULL;
}


/*
 * The messaging layer will reconnect to the osd as needed.  If the
 * session has dropped, the OSD will have dropped the session state,
 * and we'll get notified by the messaging layer.  If that happens, we
 * need to resubmit all requests for that osd.
 */
static void osd_reset(struct ceph_connection *con)
{
        struct ceph_osd *osd = con->private;
        struct ceph_osd_client *osdc;

        if (!osd)
                return;
        dout("osd_reset osd%d\n", osd->o_osd);
        osdc = osd->o_osdc;
        osd->o_incarnation++;
        down_read(&osdc->map_sem);
        kick_requests(osdc, osd);
        up_read(&osdc->map_sem);
}

/*
 * Track open sessions with osds.
 */
static struct ceph_osd *create_osd(struct ceph_osd_client *osdc)
{
        struct ceph_osd *osd;

        osd = kzalloc(sizeof(*osd), GFP_NOFS);
        if (!osd)
                return NULL;

        atomic_set(&osd->o_ref, 1);
        osd->o_osdc = osdc;
        INIT_LIST_HEAD(&osd->o_requests);
        osd->o_incarnation = 1;

        ceph_con_init(osdc->client->msgr, &osd->o_con);
        osd->o_con.private = osd;
        osd->o_con.ops = &osd_con_ops;
        osd->o_con.peer_name.type = CEPH_ENTITY_TYPE_OSD;
        return osd;
}

static struct ceph_osd *get_osd(struct ceph_osd *osd)
{
        if (atomic_inc_not_zero(&osd->o_ref)) {
                dout("get_osd %p %d -> %d\n", osd, atomic_read(&osd->o_ref)-1,
                     atomic_read(&osd->o_ref));
                return osd;
        } else {
                dout("get_osd %p FAIL\n", osd);
                return NULL;
        }
}

static void put_osd(struct ceph_osd *osd)
{
        dout("put_osd %p %d -> %d\n", osd, atomic_read(&osd->o_ref),
             atomic_read(&osd->o_ref) - 1);
        if (atomic_dec_and_test(&osd->o_ref)) {
                ceph_con_shutdown(&osd->o_con);
                kfree(osd);
        }
}

/*
 * remove an osd from our map
 */
static void remove_osd(struct ceph_osd_client *osdc, struct ceph_osd *osd)
{
        dout("remove_osd %p\n", osd);
        BUG_ON(!list_empty(&osd->o_requests));
        rb_erase(&osd->o_node, &osdc->osds);
        ceph_con_close(&osd->o_con);
        put_osd(osd);
}

/*
 * reset osd connect
 */
static int reset_osd(struct ceph_osd_client *osdc, struct ceph_osd *osd)
{
        int ret = 0;

        dout("reset_osd %p osd%d\n", osd, osd->o_osd);
        if (list_empty(&osd->o_requests)) {
                remove_osd(osdc, osd);
        } else {
                ceph_con_close(&osd->o_con);
                ceph_con_open(&osd->o_con, &osdc->osdmap->osd_addr[osd->o_osd]);
                osd->o_incarnation++;
        }
        return ret;
}

static void __insert_osd(struct ceph_osd_client *osdc, struct ceph_osd *new)
{
        struct rb_node **p = &osdc->osds.rb_node;
        struct rb_node *parent = NULL;
        struct ceph_osd *osd = NULL;

        while (*p) {
                parent = *p;
                osd = rb_entry(parent, struct ceph_osd, o_node);
                if (new->o_osd < osd->o_osd)
                        p = &(*p)->rb_left;
                else if (new->o_osd > osd->o_osd)
                        p = &(*p)->rb_right;
                else
                        BUG();
        }

        rb_link_node(&new->o_node, parent, p);
        rb_insert_color(&new->o_node, &osdc->osds);
}

static struct ceph_osd *__lookup_osd(struct ceph_osd_client *osdc, int o)
{
        struct ceph_osd *osd;
        struct rb_node *n = osdc->osds.rb_node;

        while (n) {
                osd = rb_entry(n, struct ceph_osd, o_node);
                if (o < osd->o_osd)
                        n = n->rb_left;
                else if (o > osd->o_osd)
                        n = n->rb_right;
                else
                        return osd;
        }
        return NULL;
}


/*
 * Register request, assign tid.  If this is the first request, set up
 * the timeout event.
 */
static void register_request(struct ceph_osd_client *osdc,
                             struct ceph_osd_request *req)
{
        struct ceph_osd_request_head *head = req->r_request->front.iov_base;

        mutex_lock(&osdc->request_mutex);
        req->r_tid = ++osdc->last_tid;
        head->tid = cpu_to_le64(req->r_tid);

        dout("register_request %p tid %lld\n", req, req->r_tid);
        __insert_request(osdc, req);
        ceph_osdc_get_request(req);
        osdc->num_requests++;

        req->r_timeout_stamp =
                jiffies + osdc->client->mount_args.osd_timeout*HZ;

        if (osdc->num_requests == 1) {
                osdc->timeout_tid = req->r_tid;
                dout("  timeout on tid %llu at %lu\n", req->r_tid,
                     req->r_timeout_stamp);
                schedule_delayed_work(&osdc->timeout_work,
                      round_jiffies_relative(req->r_timeout_stamp - jiffies));
        }
        mutex_unlock(&osdc->request_mutex);
}

/*
 * called under osdc->request_mutex
 */
static void __unregister_request(struct ceph_osd_client *osdc,
                                 struct ceph_osd_request *req)
{
        dout("__unregister_request %p tid %lld\n", req, req->r_tid);
        rb_erase(&req->r_node, &osdc->requests);
        osdc->num_requests--;

        list_del_init(&req->r_osd_item);
        if (list_empty(&req->r_osd->o_requests))
                remove_osd(osdc, req->r_osd);
        req->r_osd = NULL;

        ceph_osdc_put_request(req);

        if (req->r_tid == osdc->timeout_tid) {
                if (osdc->num_requests == 0) {
                        dout("no requests, canceling timeout\n");
                        osdc->timeout_tid = 0;
                        cancel_delayed_work(&osdc->timeout_work);
                } else {
                        req = rb_entry(rb_first(&osdc->requests),
                                       struct ceph_osd_request, r_node);
                        osdc->timeout_tid = req->r_tid;
                        dout("rescheduled timeout on tid %llu at %lu\n",
                             req->r_tid, req->r_timeout_stamp);
                        schedule_delayed_work(&osdc->timeout_work,
                              round_jiffies_relative(req->r_timeout_stamp -
                                                     jiffies));
                }
        }
}

/*
 * Cancel a previously queued request message
 */
static void __cancel_request(struct ceph_osd_request *req)
{
        if (req->r_sent) {
                ceph_con_revoke(&req->r_osd->o_con, req->r_request);
                req->r_sent = 0;
        }
}

/*
 * Pick an osd (the first 'up' osd in the pg), allocate the osd struct
 * (as needed), and set the request r_osd appropriately.  If there is
 * no up osd, set r_osd to NULL.
 *
 * Return 0 if unchanged, 1 if changed, or negative on error.
 *
 * Caller should hold map_sem for read and request_mutex.
 */
static int __map_osds(struct ceph_osd_client *osdc,
                      struct ceph_osd_request *req)
{
        struct ceph_osd_request_head *reqhead = req->r_request->front.iov_base;
        union ceph_pg pgid;
        int o = -1;
        int err;
        struct ceph_osd *newosd = NULL;

        dout("map_osds %p tid %lld\n", req, req->r_tid);
        err = ceph_calc_object_layout(&reqhead->layout, req->r_oid,
                                      &req->r_file_layout, osdc->osdmap);
        if (err)
                return err;
        pgid.pg64 = le64_to_cpu(reqhead->layout.ol_pgid);
        o = ceph_calc_pg_primary(osdc->osdmap, pgid);

        if ((req->r_osd && req->r_osd->o_osd == o &&
             req->r_sent >= req->r_osd->o_incarnation) ||
            (req->r_osd == NULL && o == -1))
                return 0;  /* no change */

        dout("map_osds tid %llu pgid %llx pool %d osd%d (was osd%d)\n",
             req->r_tid, pgid.pg64, pgid.pg.pool, o,
             req->r_osd ? req->r_osd->o_osd : -1);

        if (req->r_osd) {
                __cancel_request(req);
                list_del_init(&req->r_osd_item);
                if (list_empty(&req->r_osd->o_requests)) {
                        /* try to re-use r_osd if possible */
                        newosd = get_osd(req->r_osd);
                        remove_osd(osdc, newosd);
                }
                req->r_osd = NULL;
        }

        req->r_osd = __lookup_osd(osdc, o);
        if (!req->r_osd && o >= 0) {
                if (newosd) {
                        req->r_osd = newosd;
                        newosd = NULL;
                } else {
                        err = -ENOMEM;
                        req->r_osd = create_osd(osdc);
                        if (!req->r_osd)
                                goto out;
                }

                dout("map_osds osd %p is osd%d\n", req->r_osd, o);
                req->r_osd->o_osd = o;
                req->r_osd->o_con.peer_name.num = cpu_to_le64(o);
                __insert_osd(osdc, req->r_osd);

                ceph_con_open(&req->r_osd->o_con, &osdc->osdmap->osd_addr[o]);
        }

        if (req->r_osd)
                list_add(&req->r_osd_item, &req->r_osd->o_requests);
        err = 1;   /* osd changed */

out:
        if (newosd)
                put_osd(newosd);
        return err;
}

/*
 * caller should hold map_sem (for read) and request_mutex
 */
static int __send_request(struct ceph_osd_client *osdc,
                          struct ceph_osd_request *req)
{
        struct ceph_osd_request_head *reqhead;
        int err;

        err = __map_osds(osdc, req);
        if (err < 0)
                return err;
        if (req->r_osd == NULL) {
                dout("send_request %p no up osds in pg\n", req);
                ceph_monc_request_next_osdmap(&osdc->client->monc);
                return 0;
        }

        dout("send_request %p tid %llu to osd%d flags %d\n",
             req, req->r_tid, req->r_osd->o_osd, req->r_flags);

        reqhead = req->r_request->front.iov_base;
        reqhead->osdmap_epoch = cpu_to_le32(osdc->osdmap->epoch);
        reqhead->flags |= cpu_to_le32(req->r_flags);  /* e.g., RETRY */
        reqhead->reassert_version = req->r_reassert_version;

        req->r_timeout_stamp = jiffies+osdc->client->mount_args.osd_timeout*HZ;

        ceph_msg_get(req->r_request); /* send consumes a ref */
        ceph_con_send(&req->r_osd->o_con, req->r_request);
        req->r_sent = req->r_osd->o_incarnation;
        return 0;
}

/*
 * Timeout callback, called every N seconds when 1 or more osd
 * requests has been active for more than N seconds.  When this
 * happens, we ping all OSDs with requests who have timed out to
 * ensure any communications channel reset is detected.  Reset the
 * request timeouts another N seconds in the future as we go.
 * Reschedule the timeout event another N seconds in future (unless
 * there are no open requests).
 */
static void handle_timeout(struct work_struct *work)
{
        struct ceph_osd_client *osdc =
                container_of(work, struct ceph_osd_client, timeout_work.work);
        struct ceph_osd_request *req;
        struct ceph_osd *osd;
        unsigned long timeout = osdc->client->mount_args.osd_timeout * HZ;
        unsigned long next_timeout = timeout + jiffies;
        struct rb_node *p;

        dout("timeout\n");
        down_read(&osdc->map_sem);

        ceph_monc_request_next_osdmap(&osdc->client->monc);

        mutex_lock(&osdc->request_mutex);
        for (p = rb_first(&osdc->requests); p; p = rb_next(p)) {
                req = rb_entry(p, struct ceph_osd_request, r_node);

                if (req->r_resend) {
                        int err;

                        dout("osdc resending prev failed %lld\n", req->r_tid);
                        err = __send_request(osdc, req);
                        if (err)
                                dout("osdc failed again on %lld\n", req->r_tid);
                        else
                                req->r_resend = false;
                        continue;
                }
        }
        for (p = rb_first(&osdc->osds); p; p = rb_next(p)) {
                osd = rb_entry(p, struct ceph_osd, o_node);
                if (list_empty(&osd->o_requests))
                        continue;
                req = list_first_entry(&osd->o_requests,
                                       struct ceph_osd_request, r_osd_item);
                if (time_before(jiffies, req->r_timeout_stamp))
                        continue;

                dout(" tid %llu (at least) timed out on osd%d\n",
                     req->r_tid, osd->o_osd);
                req->r_timeout_stamp = next_timeout;
                ceph_con_keepalive(&osd->o_con);
        }

        if (osdc->timeout_tid)
                schedule_delayed_work(&osdc->timeout_work,
                                      round_jiffies_relative(timeout));

        mutex_unlock(&osdc->request_mutex);

        up_read(&osdc->map_sem);
}

/*
 * handle osd op reply.  either call the callback if it is specified,
 * or do the completion to wake up the waiting thread.
 */
static void handle_reply(struct ceph_osd_client *osdc, struct ceph_msg *msg)
{
        struct ceph_osd_reply_head *rhead = msg->front.iov_base;
        struct ceph_osd_request *req;
        u64 tid;
        int numops, object_len, flags;

        if (msg->front.iov_len < sizeof(*rhead))
                goto bad;
        tid = le64_to_cpu(rhead->tid);
        numops = le32_to_cpu(rhead->num_ops);
        object_len = le32_to_cpu(rhead->object_len);
        if (msg->front.iov_len != sizeof(*rhead) + object_len +
            numops * sizeof(struct ceph_osd_op))
                goto bad;
        dout("handle_reply %p tid %llu\n", msg, tid);

        /* lookup */
        mutex_lock(&osdc->request_mutex);
        req = __lookup_request(osdc, tid);
        if (req == NULL) {
                dout("handle_reply tid %llu dne\n", tid);
                mutex_unlock(&osdc->request_mutex);
                return;
        }
        ceph_osdc_get_request(req);
        flags = le32_to_cpu(rhead->flags);

        if (req->r_reply) {
                /*
                 * once we see the message has been received, we don't
                 * need a ref (which is only needed for revoking
                 * pages)
                 */
                ceph_msg_put(req->r_reply);
                req->r_reply = NULL;
        }

        if (!req->r_got_reply) {
                unsigned bytes;

                req->r_result = le32_to_cpu(rhead->result);
                bytes = le32_to_cpu(msg->hdr.data_len);
                dout("handle_reply result %d bytes %d\n", req->r_result,
                     bytes);
                if (req->r_result == 0)
                        req->r_result = bytes;

                /* in case this is a write and we need to replay, */
                req->r_reassert_version = rhead->reassert_version;

                req->r_got_reply = 1;
        } else if ((flags & CEPH_OSD_FLAG_ONDISK) == 0) {
                dout("handle_reply tid %llu dup ack\n", tid);
                goto done;
        }

        dout("handle_reply tid %llu flags %d\n", tid, flags);

        /* either this is a read, or we got the safe response */
        if ((flags & CEPH_OSD_FLAG_ONDISK) ||
            ((flags & CEPH_OSD_FLAG_WRITE) == 0))
                __unregister_request(osdc, req);

        mutex_unlock(&osdc->request_mutex);

        if (req->r_callback)
                req->r_callback(req, msg);
        else
                complete(&req->r_completion);

        if (flags & CEPH_OSD_FLAG_ONDISK) {
                if (req->r_safe_callback)
                        req->r_safe_callback(req, msg);
                complete(&req->r_safe_completion);  /* fsync waiter */
        }

done:
        ceph_osdc_put_request(req);
        return;

bad:
        pr_err("corrupt osd_op_reply got %d %d expected %d\n",
               (int)msg->front.iov_len, le32_to_cpu(msg->hdr.front_len),
               (int)sizeof(*rhead));
}


/*
 * Resubmit osd requests whose osd or osd address has changed.  Request
 * a new osd map if osds are down, or we are otherwise unable to determine
 * how to direct a request.
 *
 * Close connections to down osds.
 *
 * If @who is specified, resubmit requests for that specific osd.
 *
 * Caller should hold map_sem for read and request_mutex.
 */
static void kick_requests(struct ceph_osd_client *osdc,
                          struct ceph_osd *kickosd)
{
        struct ceph_osd_request *req;
        struct rb_node *p, *n;
        int needmap = 0;
        int err;

        dout("kick_requests osd%d\n", kickosd ? kickosd->o_osd : -1);
        mutex_lock(&osdc->request_mutex);
        if (!kickosd) {
                for (p = rb_first(&osdc->osds); p; p = n) {
                        struct ceph_osd *osd =
                                rb_entry(p, struct ceph_osd, o_node);

                        n = rb_next(p);
                        if (!ceph_osd_is_up(osdc->osdmap, osd->o_osd) ||
                            !ceph_entity_addr_equal(&osd->o_con.peer_addr,
                                            ceph_osd_addr(osdc->osdmap,
                                                          osd->o_osd)))
                                reset_osd(osdc, osd);
                }
        }

        for (p = rb_first(&osdc->requests); p; p = rb_next(p)) {
                req = rb_entry(p, struct ceph_osd_request, r_node);

                if (req->r_resend) {
                        dout(" r_resend set on tid %llu\n", req->r_tid);
                        goto kick;
                }
                if (req->r_osd && kickosd == req->r_osd)
                        goto kick;

                err = __map_osds(osdc, req);
                if (err == 0)
                        continue;  /* no change */
                if (err < 0) {
                        /*
                         * FIXME: really, we should set the request
                         * error and fail if this isn't a 'nofail'
                         * request, but that's a fair bit more
                         * complicated to do.  So retry!
                         */
                        dout(" setting r_resend on %llu\n", req->r_tid);
                        req->r_resend = true;
                        continue;
                }
                if (req->r_osd == NULL) {
                        dout("tid %llu maps to no valid osd\n", req->r_tid);
                        needmap++;  /* request a newer map */
                        continue;
                }

kick:
                dout("kicking tid %llu osd%d\n", req->r_tid, req->r_osd->o_osd);
                req->r_flags |= CEPH_OSD_FLAG_RETRY;
                err = __send_request(osdc, req);
                if (err) {
                        dout(" setting r_resend on %llu\n", req->r_tid);
                        req->r_resend = true;
                }
        }
        mutex_unlock(&osdc->request_mutex);

        if (needmap) {
                dout("%d requests for down osds, need new map\n", needmap);
                ceph_monc_request_next_osdmap(&osdc->client->monc);
        }
}

/*
 * Process updated osd map.
 *
 * The message contains any number of incremental and full maps, normally
 * indicating some sort of topology change in the cluster.  Kick requests
 * off to different OSDs as needed.
 */
void ceph_osdc_handle_map(struct ceph_osd_client *osdc, struct ceph_msg *msg)
{
        void *p, *end, *next;
        u32 nr_maps, maplen;
        u32 epoch;
        struct ceph_osdmap *newmap = NULL, *oldmap;
        int err;
        struct ceph_fsid fsid;

        dout("handle_map have %u\n", osdc->osdmap ? osdc->osdmap->epoch : 0);
        p = msg->front.iov_base;
        end = p + msg->front.iov_len;

        /* verify fsid */
        ceph_decode_need(&p, end, sizeof(fsid), bad);
        ceph_decode_copy(&p, &fsid, sizeof(fsid));
        if (ceph_fsid_compare(&fsid, &osdc->client->monc.monmap->fsid)) {
                pr_err("got osdmap with wrong fsid, ignoring\n");
                return;
        }

        down_write(&osdc->map_sem);

        /* incremental maps */
        ceph_decode_32_safe(&p, end, nr_maps, bad);
        dout(" %d inc maps\n", nr_maps);
        while (nr_maps > 0) {
                ceph_decode_need(&p, end, 2*sizeof(u32), bad);
                ceph_decode_32(&p, epoch);
                ceph_decode_32(&p, maplen);
                ceph_decode_need(&p, end, maplen, bad);
                next = p + maplen;
                if (osdc->osdmap && osdc->osdmap->epoch+1 == epoch) {
                        dout("applying incremental map %u len %d\n",
                             epoch, maplen);
                        newmap = osdmap_apply_incremental(&p, next,
                                                          osdc->osdmap,
                                                          osdc->client->msgr);
                        if (IS_ERR(newmap)) {
                                err = PTR_ERR(newmap);
                                goto bad;
                        }
                        if (newmap != osdc->osdmap) {
                                ceph_osdmap_destroy(osdc->osdmap);
                                osdc->osdmap = newmap;
                        }
                } else {
                        dout("ignoring incremental map %u len %d\n",
                             epoch, maplen);
                }
                p = next;
                nr_maps--;
        }
        if (newmap)
                goto done;

        /* full maps */
        ceph_decode_32_safe(&p, end, nr_maps, bad);
        dout(" %d full maps\n", nr_maps);
        while (nr_maps) {
                ceph_decode_need(&p, end, 2*sizeof(u32), bad);
                ceph_decode_32(&p, epoch);
                ceph_decode_32(&p, maplen);
                ceph_decode_need(&p, end, maplen, bad);
                if (nr_maps > 1) {
                        dout("skipping non-latest full map %u len %d\n",
                             epoch, maplen);
                } else if (osdc->osdmap && osdc->osdmap->epoch >= epoch) {
                        dout("skipping full map %u len %d, "
                             "older than our %u\n", epoch, maplen,
                             osdc->osdmap->epoch);
                } else {
                        dout("taking full map %u len %d\n", epoch, maplen);
                        newmap = osdmap_decode(&p, p+maplen);
                        if (IS_ERR(newmap)) {
                                err = PTR_ERR(newmap);
                                goto bad;
                        }
                        oldmap = osdc->osdmap;
                        osdc->osdmap = newmap;
                        if (oldmap)
                                ceph_osdmap_destroy(oldmap);
                }
                p += maplen;
                nr_maps--;
        }

done:
        downgrade_write(&osdc->map_sem);
        ceph_monc_got_osdmap(&osdc->client->monc, osdc->osdmap->epoch);
        if (newmap)
                kick_requests(osdc, NULL);
        up_read(&osdc->map_sem);
        return;

bad:
        pr_err("osdc handle_map corrupt msg\n");
        up_write(&osdc->map_sem);
        return;
}


/*
 * A read request prepares specific pages that data is to be read into.
 * When a message is being read off the wire, we call prepare_pages to
 * find those pages.
 *  0 = success, -1 failure.
 */
static int prepare_pages(struct ceph_connection *con, struct ceph_msg *m,
                         int want)
{
        struct ceph_osd *osd = con->private;
        struct ceph_osd_client *osdc;
        struct ceph_osd_reply_head *rhead = m->front.iov_base;
        struct ceph_osd_request *req;
        u64 tid;
        int ret = -1;
        int type = le16_to_cpu(m->hdr.type);

        if (!osd)
                return -1;
        osdc = osd->o_osdc;

        dout("prepare_pages on msg %p want %d\n", m, want);
        if (unlikely(type != CEPH_MSG_OSD_OPREPLY))
                return -1;  /* hmm! */

        tid = le64_to_cpu(rhead->tid);
        mutex_lock(&osdc->request_mutex);
        req = __lookup_request(osdc, tid);
        if (!req) {
                dout("prepare_pages unknown tid %llu\n", tid);
                goto out;
        }
        dout("prepare_pages tid %llu has %d pages, want %d\n",
             tid, req->r_num_pages, want);
        if (likely(req->r_num_pages >= want && !req->r_prepared_pages)) {
                m->pages = req->r_pages;
                m->nr_pages = req->r_num_pages;
                req->r_reply = m;  /* only for duration of read over socket */
                ceph_msg_get(m);
                req->r_prepared_pages = 1;
                ret = 0; /* success */
        }
out:
        mutex_unlock(&osdc->request_mutex);
        return ret;
}

/*
 * Register request, send initial attempt.
 */
int ceph_osdc_start_request(struct ceph_osd_client *osdc,
                            struct ceph_osd_request *req,
                            bool nofail)
{
        int rc;

        req->r_request->pages = req->r_pages;
        req->r_request->nr_pages = req->r_num_pages;

        register_request(osdc, req);

        down_read(&osdc->map_sem);
        mutex_lock(&osdc->request_mutex);
        rc = __send_request(osdc, req);
        if (rc) {
                if (nofail) {
                        dout("osdc_start_request failed send, marking %lld\n",
                             req->r_tid);
                        req->r_resend = true;
                        rc = 0;
                } else {
                        __unregister_request(osdc, req);
                }
        }
        mutex_unlock(&osdc->request_mutex);
        up_read(&osdc->map_sem);
        return rc;
}

/*
 * wait for a request to complete
 */
int ceph_osdc_wait_request(struct ceph_osd_client *osdc,
                           struct ceph_osd_request *req)
{
        int rc;

        rc = wait_for_completion_interruptible(&req->r_completion);
        if (rc < 0) {
                mutex_lock(&osdc->request_mutex);
                __cancel_request(req);
                mutex_unlock(&osdc->request_mutex);
                dout("wait_request tid %llu timed out\n", req->r_tid);
                return rc;
        }

        dout("wait_request tid %llu result %d\n", req->r_tid, req->r_result);
        return req->r_result;
}

/*
 * sync - wait for all in-flight requests to flush.  avoid starvation.
 */
void ceph_osdc_sync(struct ceph_osd_client *osdc)
{
        struct ceph_osd_request *req;
        u64 last_tid, next_tid = 0;

        mutex_lock(&osdc->request_mutex);
        last_tid = osdc->last_tid;
        while (1) {
                req = __lookup_request_ge(osdc, next_tid);
                if (!req)
                        break;
                if (req->r_tid > last_tid)
                        break;

                next_tid = req->r_tid + 1;
                if ((req->r_flags & CEPH_OSD_FLAG_WRITE) == 0)
                        continue;

                ceph_osdc_get_request(req);
                mutex_unlock(&osdc->request_mutex);
                dout("sync waiting on tid %llu (last is %llu)\n",
                     req->r_tid, last_tid);
                wait_for_completion(&req->r_safe_completion);
                mutex_lock(&osdc->request_mutex);
                ceph_osdc_put_request(req);
        }
        mutex_unlock(&osdc->request_mutex);
        dout("sync done (thru tid %llu)\n", last_tid);
}

/*
 * init, shutdown
 */
int ceph_osdc_init(struct ceph_osd_client *osdc, struct ceph_client *client)
{
        int err;

        dout("init\n");
        osdc->client = client;
        osdc->osdmap = NULL;
        init_rwsem(&osdc->map_sem);
        init_completion(&osdc->map_waiters);
        osdc->last_requested_map = 0;
        mutex_init(&osdc->request_mutex);
        osdc->timeout_tid = 0;
        osdc->last_tid = 0;
        osdc->osds = RB_ROOT;
        osdc->requests = RB_ROOT;
        osdc->num_requests = 0;
        INIT_DELAYED_WORK(&osdc->timeout_work, handle_timeout);

        osdc->req_mempool = mempool_create_kmalloc_pool(10,
                                        sizeof(struct ceph_osd_request));
        if (!osdc->req_mempool)
                return -ENOMEM;

        err = ceph_msgpool_init(&osdc->msgpool_op, 4096, 10, true);
        if (err < 0)
                return -ENOMEM;
        err = ceph_msgpool_init(&osdc->msgpool_op_reply, 512, 0, false);
        if (err < 0)
                return -ENOMEM;

        return 0;
}

void ceph_osdc_stop(struct ceph_osd_client *osdc)
{
        cancel_delayed_work_sync(&osdc->timeout_work);
        if (osdc->osdmap) {
                ceph_osdmap_destroy(osdc->osdmap);
                osdc->osdmap = NULL;
        }
        mempool_destroy(osdc->req_mempool);
        ceph_msgpool_destroy(&osdc->msgpool_op);
        ceph_msgpool_destroy(&osdc->msgpool_op_reply);
}

/*
 * Read some contiguous pages.  If we cross a stripe boundary, shorten
 * *plen.  Return number of bytes read, or error.
 */
int ceph_osdc_readpages(struct ceph_osd_client *osdc,
                        struct ceph_vino vino, struct ceph_file_layout *layout,
                        u64 off, u64 *plen,
                        u32 truncate_seq, u64 truncate_size,
                        struct page **pages, int num_pages)
{
        struct ceph_osd_request *req;
        int rc = 0;

        dout("readpages on ino %llx.%llx on %llu~%llu\n", vino.ino,
             vino.snap, off, *plen);
        req = ceph_osdc_new_request(osdc, layout, vino, off, plen,
                                    CEPH_OSD_OP_READ, CEPH_OSD_FLAG_READ,
                                    NULL, 0, truncate_seq, truncate_size, NULL,
                                    false, 1);
        if (IS_ERR(req))
                return PTR_ERR(req);

        /* it may be a short read due to an object boundary */
        req->r_pages = pages;
        num_pages = calc_pages_for(off, *plen);
        req->r_num_pages = num_pages;

        dout("readpages  final extent is %llu~%llu (%d pages)\n",
             off, *plen, req->r_num_pages);

        rc = ceph_osdc_start_request(osdc, req, false);
        if (!rc)
                rc = ceph_osdc_wait_request(osdc, req);

        ceph_osdc_put_request(req);
        dout("readpages result %d\n", rc);
        return rc;
}

/*
 * do a synchronous write on N pages
 */
int ceph_osdc_writepages(struct ceph_osd_client *osdc, struct ceph_vino vino,
                         struct ceph_file_layout *layout,
                         struct ceph_snap_context *snapc,
                         u64 off, u64 len,
                         u32 truncate_seq, u64 truncate_size,
                         struct timespec *mtime,
                         struct page **pages, int num_pages,
                         int flags, int do_sync, bool nofail)
{
        struct ceph_osd_request *req;
        int rc = 0;

        BUG_ON(vino.snap != CEPH_NOSNAP);
        req = ceph_osdc_new_request(osdc, layout, vino, off, &len,
                                    CEPH_OSD_OP_WRITE,
                                    flags | CEPH_OSD_FLAG_ONDISK |
                                            CEPH_OSD_FLAG_WRITE,
                                    snapc, do_sync,
                                    truncate_seq, truncate_size, mtime,
                                    nofail, 1);
        if (IS_ERR(req))
                return PTR_ERR(req);

        /* it may be a short write due to an object boundary */
        req->r_pages = pages;
        req->r_num_pages = calc_pages_for(off, len);
        dout("writepages %llu~%llu (%d pages)\n", off, len,
             req->r_num_pages);

        rc = ceph_osdc_start_request(osdc, req, nofail);
        if (!rc)
                rc = ceph_osdc_wait_request(osdc, req);

        ceph_osdc_put_request(req);
        if (rc == 0)
                rc = len;
        dout("writepages result %d\n", rc);
        return rc;
}

/*
 * handle incoming message
 */
static void dispatch(struct ceph_connection *con, struct ceph_msg *msg)
{
        struct ceph_osd *osd = con->private;
        struct ceph_osd_client *osdc = osd->o_osdc;
        int type = le16_to_cpu(msg->hdr.type);

        if (!osd)
                return;

        switch (type) {
        case CEPH_MSG_OSD_MAP:
                ceph_osdc_handle_map(osdc, msg);
                break;
        case CEPH_MSG_OSD_OPREPLY:
                handle_reply(osdc, msg);
                break;

        default:
                pr_err("received unknown message type %d %s\n", type,
                       ceph_msg_type_name(type));
        }
        ceph_msg_put(msg);
}

static struct ceph_msg *alloc_msg(struct ceph_connection *con,
                                  struct ceph_msg_header *hdr)
{
        struct ceph_osd *osd = con->private;
        struct ceph_osd_client *osdc = osd->o_osdc;
        int type = le16_to_cpu(hdr->type);

        switch (type) {
        case CEPH_MSG_OSD_OPREPLY:
                return ceph_msgpool_get(&osdc->msgpool_op_reply);
        }
        return ceph_alloc_msg(con, hdr);
}

/*
 * Wrappers to refcount containing ceph_osd struct
 */
static struct ceph_connection *get_osd_con(struct ceph_connection *con)
{
        struct ceph_osd *osd = con->private;
        if (get_osd(osd))
                return con;
        return NULL;
}

static void put_osd_con(struct ceph_connection *con)
{
        struct ceph_osd *osd = con->private;
        put_osd(osd);
}

const static struct ceph_connection_operations osd_con_ops = {
        .get = get_osd_con,
        .put = put_osd_con,
        .dispatch = dispatch,
        .alloc_msg = alloc_msg,
        .peer_reset = osd_reset,
        .alloc_middle = ceph_alloc_middle,
        .prepare_pages = prepare_pages,
};