osd_client.c

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#include <linux/ceph/ceph_debug.h>

#include <linux/module.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>
#ifdef CONFIG_BLOCK
#include <linux/bio.h>
#endif

#include <linux/ceph/libceph.h>
#include <linux/ceph/osd_client.h>
#include <linux/ceph/messenger.h>
#include <linux/ceph/decode.h>
#include <linux/ceph/auth.h>
#include <linux/ceph/pagelist.h>

#define OSD_OP_FRONT_LEN    4096
#define OSD_OPREPLY_FRONT_LEN   512

static const struct ceph_connection_operations osd_con_ops;

static void send_queued(struct ceph_osd_client *osdc);
static int __reset_osd(struct ceph_osd_client *osdc, struct ceph_osd *osd);
static void __register_request(struct ceph_osd_client *osdc,
                   struct ceph_osd_request *req);
static void __unregister_linger_request(struct ceph_osd_client *osdc,
                    struct ceph_osd_request *req);
static void __send_request(struct ceph_osd_client *osdc,
               struct ceph_osd_request *req);

static int op_needs_trail(int op)
{
    switch (op) {
    case CEPH_OSD_OP_GETXATTR:
    case CEPH_OSD_OP_SETXATTR:
    case CEPH_OSD_OP_CMPXATTR:
    case CEPH_OSD_OP_CALL:
    case CEPH_OSD_OP_NOTIFY:
        return 1;
    default:
        return 0;
    }
}

static int op_has_extent(int op)
{
    return (op == CEPH_OSD_OP_READ ||
        op == CEPH_OSD_OP_WRITE);
}

int ceph_calc_raw_layout(struct ceph_osd_client *osdc,
            struct ceph_file_layout *layout,
            u64 snapid,
            u64 off, u64 *plen, u64 *bno,
            struct ceph_osd_request *req,
            struct ceph_osd_req_op *op)
{
    struct ceph_osd_request_head *reqhead = req->r_request->front.iov_base;
    u64 orig_len = *plen;
    u64 objoff, objlen;    /* extent in object */
    int r;

    reqhead->snapid = cpu_to_le64(snapid);

    /* object extent? */
    r = ceph_calc_file_object_mapping(layout, off, plen, bno,
                      &objoff, &objlen);
    if (r < 0)
        return r;
    if (*plen < orig_len)
        dout(" skipping last %llu, final file extent %llu~%llu\n",
             orig_len - *plen, off, *plen);

    if (op_has_extent(op->op)) {
        op->extent.offset = objoff;
        op->extent.length = objlen;
    }
    req->r_num_pages = calc_pages_for(off, *plen);
    req->r_page_alignment = off & ~PAGE_MASK;
    if (op->op == CEPH_OSD_OP_WRITE)
        op->payload_len = *plen;

    dout("calc_layout bno=%llx %llu~%llu (%d pages)\n",
         *bno, objoff, objlen, req->r_num_pages);
    return 0;
}
EXPORT_SYMBOL(ceph_calc_raw_layout);

/*
 * 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 int 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_req_op *op)
{
    u64 bno;
    int r;

    r = ceph_calc_raw_layout(osdc, layout, vino.snap, off,
                 plen, &bno, req, op);
    if (r < 0)
        return r;

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

    return r;
}

/*
 * requests
 */
void ceph_osdc_release_request(struct kref *kref)
{
    struct ceph_osd_request *req = container_of(kref,
                            struct ceph_osd_request,
                            r_kref);

    if (req->r_request)
        ceph_msg_put(req->r_request);
    if (req->r_con_filling_msg) {
        dout("%s revoking pages %p from con %p\n", __func__,
             req->r_pages, req->r_con_filling_msg);
        ceph_msg_revoke_incoming(req->r_reply);
        req->r_con_filling_msg->ops->put(req->r_con_filling_msg);
    }
    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);
#ifdef CONFIG_BLOCK
    if (req->r_bio)
        bio_put(req->r_bio);
#endif
    ceph_put_snap_context(req->r_snapc);
    if (req->r_trail) {
        ceph_pagelist_release(req->r_trail);
        kfree(req->r_trail);
    }
    if (req->r_mempool)
        mempool_free(req, req->r_osdc->req_mempool);
    else
        kfree(req);
}
EXPORT_SYMBOL(ceph_osdc_release_request);

static int get_num_ops(struct ceph_osd_req_op *ops, int *needs_trail)
{
    int i = 0;

    if (needs_trail)
        *needs_trail = 0;
    while (ops[i].op) {
        if (needs_trail && op_needs_trail(ops[i].op))
            *needs_trail = 1;
        i++;
    }

    return i;
}

struct ceph_osd_request *ceph_osdc_alloc_request(struct ceph_osd_client *osdc,
                           int flags,
                           struct ceph_snap_context *snapc,
                           struct ceph_osd_req_op *ops,
                           bool use_mempool,
                           gfp_t gfp_flags,
                           struct page **pages,
                           struct bio *bio)
{
    struct ceph_osd_request *req;
    struct ceph_msg *msg;
    int needs_trail;
    int num_op = get_num_ops(ops, &needs_trail);
    size_t msg_size = sizeof(struct ceph_osd_request_head);

    msg_size += num_op*sizeof(struct ceph_osd_op);

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

    req->r_osdc = osdc;
    req->r_mempool = use_mempool;

    kref_init(&req->r_kref);
    init_completion(&req->r_completion);
    init_completion(&req->r_safe_completion);
    INIT_LIST_HEAD(&req->r_unsafe_item);
    INIT_LIST_HEAD(&req->r_linger_item);
    INIT_LIST_HEAD(&req->r_linger_osd);
    INIT_LIST_HEAD(&req->r_req_lru_item);
    INIT_LIST_HEAD(&req->r_osd_item);

    req->r_flags = flags;

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

    /* create reply message */
    if (use_mempool)
        msg = ceph_msgpool_get(&osdc->msgpool_op_reply, 0);
    else
        msg = ceph_msg_new(CEPH_MSG_OSD_OPREPLY,
                   OSD_OPREPLY_FRONT_LEN, gfp_flags, true);
    if (!msg) {
        ceph_osdc_put_request(req);
        return NULL;
    }
    req->r_reply = msg;

    /* allocate space for the trailing data */
    if (needs_trail) {
        req->r_trail = kmalloc(sizeof(struct ceph_pagelist), gfp_flags);
        if (!req->r_trail) {
            ceph_osdc_put_request(req);
            return NULL;
        }
        ceph_pagelist_init(req->r_trail);
    }

    /* create request message; allow space for oid */
    msg_size += MAX_OBJ_NAME_SIZE;
    if (snapc)
        msg_size += sizeof(u64) * snapc->num_snaps;
    if (use_mempool)
        msg = ceph_msgpool_get(&osdc->msgpool_op, 0);
    else
        msg = ceph_msg_new(CEPH_MSG_OSD_OP, msg_size, gfp_flags, true);
    if (!msg) {
        ceph_osdc_put_request(req);
        return NULL;
    }

    memset(msg->front.iov_base, 0, msg->front.iov_len);

    req->r_request = msg;
    req->r_pages = pages;
#ifdef CONFIG_BLOCK
    if (bio) {
        req->r_bio = bio;
        bio_get(req->r_bio);
    }
#endif

    return req;
}
EXPORT_SYMBOL(ceph_osdc_alloc_request);

static void osd_req_encode_op(struct ceph_osd_request *req,
                  struct ceph_osd_op *dst,
                  struct ceph_osd_req_op *src)
{
    dst->op = cpu_to_le16(src->op);

    switch (src->op) {
    case CEPH_OSD_OP_READ:
    case CEPH_OSD_OP_WRITE:
        dst->extent.offset =
            cpu_to_le64(src->extent.offset);
        dst->extent.length =
            cpu_to_le64(src->extent.length);
        dst->extent.truncate_size =
            cpu_to_le64(src->extent.truncate_size);
        dst->extent.truncate_seq =
            cpu_to_le32(src->extent.truncate_seq);
        break;

    case CEPH_OSD_OP_GETXATTR:
    case CEPH_OSD_OP_SETXATTR:
    case CEPH_OSD_OP_CMPXATTR:
        BUG_ON(!req->r_trail);

        dst->xattr.name_len = cpu_to_le32(src->xattr.name_len);
        dst->xattr.value_len = cpu_to_le32(src->xattr.value_len);
        dst->xattr.cmp_op = src->xattr.cmp_op;
        dst->xattr.cmp_mode = src->xattr.cmp_mode;
        ceph_pagelist_append(req->r_trail, src->xattr.name,
                     src->xattr.name_len);
        ceph_pagelist_append(req->r_trail, src->xattr.val,
                     src->xattr.value_len);
        break;
    case CEPH_OSD_OP_CALL:
        BUG_ON(!req->r_trail);

        dst->cls.class_len = src->cls.class_len;
        dst->cls.method_len = src->cls.method_len;
        dst->cls.indata_len = cpu_to_le32(src->cls.indata_len);

        ceph_pagelist_append(req->r_trail, src->cls.class_name,
                     src->cls.class_len);
        ceph_pagelist_append(req->r_trail, src->cls.method_name,
                     src->cls.method_len);
        ceph_pagelist_append(req->r_trail, src->cls.indata,
                     src->cls.indata_len);
        break;
    case CEPH_OSD_OP_ROLLBACK:
        dst->snap.snapid = cpu_to_le64(src->snap.snapid);
        break;
    case CEPH_OSD_OP_STARTSYNC:
        break;
    case CEPH_OSD_OP_NOTIFY:
        {
            __le32 prot_ver = cpu_to_le32(src->watch.prot_ver);
            __le32 timeout = cpu_to_le32(src->watch.timeout);

            BUG_ON(!req->r_trail);

            ceph_pagelist_append(req->r_trail,
                        &prot_ver, sizeof(prot_ver));
            ceph_pagelist_append(req->r_trail,
                        &timeout, sizeof(timeout));
        }
    case CEPH_OSD_OP_NOTIFY_ACK:
    case CEPH_OSD_OP_WATCH:
        dst->watch.cookie = cpu_to_le64(src->watch.cookie);
        dst->watch.ver = cpu_to_le64(src->watch.ver);
        dst->watch.flag = src->watch.flag;
        break;
    default:
        pr_err("unrecognized osd opcode %d\n", dst->op);
        WARN_ON(1);
        break;
    }
    dst->payload_len = cpu_to_le32(src->payload_len);
}

/*
 * build new request AND message
 *
 */
void ceph_osdc_build_request(struct ceph_osd_request *req,
                 u64 off, u64 *plen,
                 struct ceph_osd_req_op *src_ops,
                 struct ceph_snap_context *snapc,
                 struct timespec *mtime,
                 const char *oid,
                 int oid_len)
{
    struct ceph_msg *msg = req->r_request;
    struct ceph_osd_request_head *head;
    struct ceph_osd_req_op *src_op;
    struct ceph_osd_op *op;
    void *p;
    int num_op = get_num_ops(src_ops, NULL);
    size_t msg_size = sizeof(*head) + num_op*sizeof(*op);
    int flags = req->r_flags;
    u64 data_len = 0;
    int i;

    head = msg->front.iov_base;
    op = (void *)(head + 1);
    p = (void *)(op + num_op);

    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);


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

    src_op = src_ops;
    while (src_op->op) {
        osd_req_encode_op(req, op, src_op);
        src_op++;
        op++;
    }

    if (req->r_trail)
        data_len += req->r_trail->length;

    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);
        }
    }

    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 + data_len);
    } else if (data_len) {
        req->r_request->hdr.data_off = 0;
        req->r_request->hdr.data_len = cpu_to_le32(data_len);
    }

    req->r_request->page_alignment = req->r_page_alignment;

    BUG_ON(p > msg->front.iov_base + msg->front.iov_len);
    msg_size = p - msg->front.iov_base;
    msg->front.iov_len = msg_size;
    msg->hdr.front_len = cpu_to_le32(msg_size);
    return;
}
EXPORT_SYMBOL(ceph_osdc_build_request);

/*
 * 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,
                           int page_align)
{
    struct ceph_osd_req_op ops[3];
    struct ceph_osd_request *req;
    int r;

    ops[0].op = opcode;
    ops[0].extent.truncate_seq = truncate_seq;
    ops[0].extent.truncate_size = truncate_size;
    ops[0].payload_len = 0;

    if (do_sync) {
        ops[1].op = CEPH_OSD_OP_STARTSYNC;
        ops[1].payload_len = 0;
        ops[2].op = 0;
    } else
        ops[1].op = 0;

    req = ceph_osdc_alloc_request(osdc, flags,
                     snapc, ops,
                     use_mempool,
                     GFP_NOFS, NULL, NULL);
    if (!req)
        return ERR_PTR(-ENOMEM);

    /* calculate max write size */
    r = calc_layout(osdc, vino, layout, off, plen, req, ops);
    if (r < 0)
        return ERR_PTR(r);
    req->r_file_layout = *layout;  /* keep a copy */

    /* in case it differs from natural (file) alignment that
       calc_layout filled in for us */
    req->r_num_pages = calc_pages_for(page_align, *plen);
    req->r_page_alignment = page_align;

    ceph_osdc_build_request(req, off, plen, ops,
                snapc,
                mtime,
                req->r_oid, req->r_oid_len);

    return req;
}
EXPORT_SYMBOL(ceph_osdc_new_request);

/*
 * 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;
}

/*
 * Resubmit requests pending on the given osd.
 */
static void __kick_osd_requests(struct ceph_osd_client *osdc,
                struct ceph_osd *osd)
{
    struct ceph_osd_request *req, *nreq;
    int err;

    dout("__kick_osd_requests osd%d\n", osd->o_osd);
    err = __reset_osd(osdc, osd);
    if (err == -EAGAIN)
        return;

    list_for_each_entry(req, &osd->o_requests, r_osd_item) {
        list_move(&req->r_req_lru_item, &osdc->req_unsent);
        dout("requeued %p tid %llu osd%d\n", req, req->r_tid,
             osd->o_osd);
        if (!req->r_linger)
            req->r_flags |= CEPH_OSD_FLAG_RETRY;
    }

    list_for_each_entry_safe(req, nreq, &osd->o_linger_requests,
                 r_linger_osd) {
        /*
         * reregister request prior to unregistering linger so
         * that r_osd is preserved.
         */
        BUG_ON(!list_empty(&req->r_req_lru_item));
        __register_request(osdc, req);
        list_add(&req->r_req_lru_item, &osdc->req_unsent);
        list_add(&req->r_osd_item, &req->r_osd->o_requests);
        __unregister_linger_request(osdc, req);
        dout("requeued lingering %p tid %llu osd%d\n", req, req->r_tid,
             osd->o_osd);
    }
}

static void kick_osd_requests(struct ceph_osd_client *osdc,
                  struct ceph_osd *kickosd)
{
    mutex_lock(&osdc->request_mutex);
    __kick_osd_requests(osdc, kickosd);
    mutex_unlock(&osdc->request_mutex);
}

/*
 * If the osd connection drops, we need to resubmit all requests.
 */
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;
    down_read(&osdc->map_sem);
    kick_osd_requests(osdc, osd);
    send_queued(osdc);
    up_read(&osdc->map_sem);
}

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

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

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

    ceph_con_init(&osd->o_con, osd, &osd_con_ops, &osdc->client->msgr);

    INIT_LIST_HEAD(&osd->o_keepalive_item);
    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) && osd->o_auth.authorizer) {
        struct ceph_auth_client *ac = osd->o_osdc->client->monc.auth;

        if (ac->ops && ac->ops->destroy_authorizer)
            ac->ops->destroy_authorizer(ac, osd->o_auth.authorizer);
        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);
    list_del_init(&osd->o_osd_lru);
    ceph_con_close(&osd->o_con);
    put_osd(osd);
}

static void remove_all_osds(struct ceph_osd_client *osdc)
{
    dout("%s %p\n", __func__, osdc);
    mutex_lock(&osdc->request_mutex);
    while (!RB_EMPTY_ROOT(&osdc->osds)) {
        struct ceph_osd *osd = rb_entry(rb_first(&osdc->osds),
                        struct ceph_osd, o_node);
        __remove_osd(osdc, osd);
    }
    mutex_unlock(&osdc->request_mutex);
}

static void __move_osd_to_lru(struct ceph_osd_client *osdc,
                  struct ceph_osd *osd)
{
    dout("__move_osd_to_lru %p\n", osd);
    BUG_ON(!list_empty(&osd->o_osd_lru));
    list_add_tail(&osd->o_osd_lru, &osdc->osd_lru);
    osd->lru_ttl = jiffies + osdc->client->options->osd_idle_ttl * HZ;
}

static void __remove_osd_from_lru(struct ceph_osd *osd)
{
    dout("__remove_osd_from_lru %p\n", osd);
    if (!list_empty(&osd->o_osd_lru))
        list_del_init(&osd->o_osd_lru);
}

static void remove_old_osds(struct ceph_osd_client *osdc)
{
    struct ceph_osd *osd, *nosd;

    dout("__remove_old_osds %p\n", osdc);
    mutex_lock(&osdc->request_mutex);
    list_for_each_entry_safe(osd, nosd, &osdc->osd_lru, o_osd_lru) {
        if (time_before(jiffies, osd->lru_ttl))
            break;
        __remove_osd(osdc, osd);
    }
    mutex_unlock(&osdc->request_mutex);
}

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

    dout("__reset_osd %p osd%d\n", osd, osd->o_osd);
    if (list_empty(&osd->o_requests) &&
        list_empty(&osd->o_linger_requests)) {
        __remove_osd(osdc, osd);
    } else if (memcmp(&osdc->osdmap->osd_addr[osd->o_osd],
              &osd->o_con.peer_addr,
              sizeof(osd->o_con.peer_addr)) == 0 &&
           !ceph_con_opened(&osd->o_con)) {
        dout(" osd addr hasn't changed and connection never opened,"
             " letting msgr retry");
        /* touch each r_stamp for handle_timeout()'s benfit */
        list_for_each_entry(req, &osd->o_requests, r_osd_item)
            req->r_stamp = jiffies;
        ret = -EAGAIN;
    } else {
        ceph_con_close(&osd->o_con);
        ceph_con_open(&osd->o_con, CEPH_ENTITY_TYPE_OSD, osd->o_osd,
                  &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;

    dout("__insert_osd %p osd%d\n", new, new->o_osd);
    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;
}

static void __schedule_osd_timeout(struct ceph_osd_client *osdc)
{
    schedule_delayed_work(&osdc->timeout_work,
            osdc->client->options->osd_keepalive_timeout * HZ);
}

static void __cancel_osd_timeout(struct ceph_osd_client *osdc)
{
    cancel_delayed_work(&osdc->timeout_work);
}

/*
 * 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)
{
    req->r_tid = ++osdc->last_tid;
    req->r_request->hdr.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++;
    if (osdc->num_requests == 1) {
        dout(" first request, scheduling timeout\n");
        __schedule_osd_timeout(osdc);
    }
}

static void register_request(struct ceph_osd_client *osdc,
                 struct ceph_osd_request *req)
{
    mutex_lock(&osdc->request_mutex);
    __register_request(osdc, req);
    mutex_unlock(&osdc->request_mutex);
}

/*
 * called under osdc->request_mutex
 */
static void __unregister_request(struct ceph_osd_client *osdc,
                 struct ceph_osd_request *req)
{
    if (RB_EMPTY_NODE(&req->r_node)) {
        dout("__unregister_request %p tid %lld not registered\n",
            req, req->r_tid);
        return;
    }

    dout("__unregister_request %p tid %lld\n", req, req->r_tid);
    rb_erase(&req->r_node, &osdc->requests);
    osdc->num_requests--;

    if (req->r_osd) {
        /* make sure the original request isn't in flight. */
        ceph_msg_revoke(req->r_request);

        list_del_init(&req->r_osd_item);
        if (list_empty(&req->r_osd->o_requests) &&
            list_empty(&req->r_osd->o_linger_requests)) {
            dout("moving osd to %p lru\n", req->r_osd);
            __move_osd_to_lru(osdc, req->r_osd);
        }
        if (list_empty(&req->r_linger_item))
            req->r_osd = NULL;
    }

    ceph_osdc_put_request(req);

    list_del_init(&req->r_req_lru_item);
    if (osdc->num_requests == 0) {
        dout(" no requests, canceling timeout\n");
        __cancel_osd_timeout(osdc);
    }
}

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

static void __register_linger_request(struct ceph_osd_client *osdc,
                    struct ceph_osd_request *req)
{
    dout("__register_linger_request %p\n", req);
    list_add_tail(&req->r_linger_item, &osdc->req_linger);
    if (req->r_osd)
        list_add_tail(&req->r_linger_osd,
                  &req->r_osd->o_linger_requests);
}

static void __unregister_linger_request(struct ceph_osd_client *osdc,
                    struct ceph_osd_request *req)
{
    dout("__unregister_linger_request %p\n", req);
    if (req->r_osd) {
        list_del_init(&req->r_linger_item);
        list_del_init(&req->r_linger_osd);

        if (list_empty(&req->r_osd->o_requests) &&
            list_empty(&req->r_osd->o_linger_requests)) {
            dout("moving osd to %p lru\n", req->r_osd);
            __move_osd_to_lru(osdc, req->r_osd);
        }
        if (list_empty(&req->r_osd_item))
            req->r_osd = NULL;
    }
}

void ceph_osdc_unregister_linger_request(struct ceph_osd_client *osdc,
                     struct ceph_osd_request *req)
{
    mutex_lock(&osdc->request_mutex);
    if (req->r_linger) {
        __unregister_linger_request(osdc, req);
        ceph_osdc_put_request(req);
    }
    mutex_unlock(&osdc->request_mutex);
}
EXPORT_SYMBOL(ceph_osdc_unregister_linger_request);

void ceph_osdc_set_request_linger(struct ceph_osd_client *osdc,
                  struct ceph_osd_request *req)
{
    if (!req->r_linger) {
        dout("set_request_linger %p\n", req);
        req->r_linger = 1;
        /*
         * caller is now responsible for calling
         * unregister_linger_request
         */
        ceph_osdc_get_request(req);
    }
}
EXPORT_SYMBOL(ceph_osdc_set_request_linger);

/*
 * 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.  Move the request to the appropriate list
 * (unsent, homeless) or leave on in-flight lru.
 *
 * Return 0 if unchanged, 1 if changed, or negative on error.
 *
 * Caller should hold map_sem for read and request_mutex.
 */
static int __map_request(struct ceph_osd_client *osdc,
             struct ceph_osd_request *req, int force_resend)
{
    struct ceph_osd_request_head *reqhead = req->r_request->front.iov_base;
    struct ceph_pg pgid;
    int acting[CEPH_PG_MAX_SIZE];
    int o = -1, num = 0;
    int err;

    dout("map_request %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) {
        list_move(&req->r_req_lru_item, &osdc->req_notarget);
        return err;
    }
    pgid = reqhead->layout.ol_pgid;
    req->r_pgid = pgid;

    err = ceph_calc_pg_acting(osdc->osdmap, pgid, acting);
    if (err > 0) {
        o = acting[0];
        num = err;
    }

    if ((!force_resend &&
         req->r_osd && req->r_osd->o_osd == o &&
         req->r_sent >= req->r_osd->o_incarnation &&
         req->r_num_pg_osds == num &&
         memcmp(req->r_pg_osds, acting, sizeof(acting[0])*num) == 0) ||
        (req->r_osd == NULL && o == -1))
        return 0;  /* no change */

    dout("map_request tid %llu pgid %d.%x osd%d (was osd%d)\n",
         req->r_tid, le32_to_cpu(pgid.pool), le16_to_cpu(pgid.ps), o,
         req->r_osd ? req->r_osd->o_osd : -1);

    /* record full pg acting set */
    memcpy(req->r_pg_osds, acting, sizeof(acting[0]) * num);
    req->r_num_pg_osds = num;

    if (req->r_osd) {
        __cancel_request(req);
        list_del_init(&req->r_osd_item);
        req->r_osd = NULL;
    }

    req->r_osd = __lookup_osd(osdc, o);
    if (!req->r_osd && o >= 0) {
        err = -ENOMEM;
        req->r_osd = create_osd(osdc, o);
        if (!req->r_osd) {
            list_move(&req->r_req_lru_item, &osdc->req_notarget);
            goto out;
        }

        dout("map_request osd %p is osd%d\n", req->r_osd, o);
        __insert_osd(osdc, req->r_osd);

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

    if (req->r_osd) {
        __remove_osd_from_lru(req->r_osd);
        list_add(&req->r_osd_item, &req->r_osd->o_requests);
        list_move(&req->r_req_lru_item, &osdc->req_unsent);
    } else {
        list_move(&req->r_req_lru_item, &osdc->req_notarget);
    }
    err = 1;   /* osd or pg changed */

out:
    return err;
}

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

    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_stamp = jiffies;
    list_move_tail(&req->r_req_lru_item, &osdc->req_lru);

    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;
}

/*
 * Send any requests in the queue (req_unsent).
 */
static void send_queued(struct ceph_osd_client *osdc)
{
    struct ceph_osd_request *req, *tmp;

    dout("send_queued\n");
    mutex_lock(&osdc->request_mutex);
    list_for_each_entry_safe(req, tmp, &osdc->req_unsent, r_req_lru_item) {
        __send_request(osdc, req);
    }
    mutex_unlock(&osdc->request_mutex);
}

/*
 * 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, *last_req = NULL;
    struct ceph_osd *osd;
    unsigned long timeout = osdc->client->options->osd_timeout * HZ;
    unsigned long keepalive =
        osdc->client->options->osd_keepalive_timeout * HZ;
    unsigned long last_stamp = 0;
    struct list_head slow_osds;
    dout("timeout\n");
    down_read(&osdc->map_sem);

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

    mutex_lock(&osdc->request_mutex);

    /*
     * reset osds that appear to be _really_ unresponsive.  this
     * is a failsafe measure.. we really shouldn't be getting to
     * this point if the system is working properly.  the monitors
     * should mark the osd as failed and we should find out about
     * it from an updated osd map.
     */
    while (timeout && !list_empty(&osdc->req_lru)) {
        req = list_entry(osdc->req_lru.next, struct ceph_osd_request,
                 r_req_lru_item);

        /* hasn't been long enough since we sent it? */
        if (time_before(jiffies, req->r_stamp + timeout))
            break;

        /* hasn't been long enough since it was acked? */
        if (req->r_request->ack_stamp == 0 ||
            time_before(jiffies, req->r_request->ack_stamp + timeout))
            break;

        BUG_ON(req == last_req && req->r_stamp == last_stamp);
        last_req = req;
        last_stamp = req->r_stamp;

        osd = req->r_osd;
        BUG_ON(!osd);
        pr_warning(" tid %llu timed out on osd%d, will reset osd\n",
               req->r_tid, osd->o_osd);
        __kick_osd_requests(osdc, osd);
    }

    /*
     * ping osds that are a bit slow.  this ensures that if there
     * is a break in the TCP connection we will notice, and reopen
     * a connection with that osd (from the fault callback).
     */
    INIT_LIST_HEAD(&slow_osds);
    list_for_each_entry(req, &osdc->req_lru, r_req_lru_item) {
        if (time_before(jiffies, req->r_stamp + keepalive))
            break;

        osd = req->r_osd;
        BUG_ON(!osd);
        dout(" tid %llu is slow, will send keepalive on osd%d\n",
             req->r_tid, osd->o_osd);
        list_move_tail(&osd->o_keepalive_item, &slow_osds);
    }
    while (!list_empty(&slow_osds)) {
        osd = list_entry(slow_osds.next, struct ceph_osd,
                 o_keepalive_item);
        list_del_init(&osd->o_keepalive_item);
        ceph_con_keepalive(&osd->o_con);
    }

    __schedule_osd_timeout(osdc);
    mutex_unlock(&osdc->request_mutex);
    send_queued(osdc);
    up_read(&osdc->map_sem);
}

static void handle_osds_timeout(struct work_struct *work)
{
    struct ceph_osd_client *osdc =
        container_of(work, struct ceph_osd_client,
                 osds_timeout_work.work);
    unsigned long delay =
        osdc->client->options->osd_idle_ttl * HZ >> 2;

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

    schedule_delayed_work(&osdc->osds_timeout_work,
                  round_jiffies_relative(delay));
}

static void complete_request(struct ceph_osd_request *req)
{
    if (req->r_safe_callback)
        req->r_safe_callback(req, NULL);
    complete_all(&req->r_safe_completion);  /* fsync waiter */
}

/*
 * 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_connection *con)
{
    struct ceph_osd_reply_head *rhead = msg->front.iov_base;
    struct ceph_osd_request *req;
    u64 tid;
    int numops, object_len, flags;
    s32 result;

    tid = le64_to_cpu(msg->hdr.tid);
    if (msg->front.iov_len < sizeof(*rhead))
        goto bad;
    numops = le32_to_cpu(rhead->num_ops);
    object_len = le32_to_cpu(rhead->object_len);
    result = le32_to_cpu(rhead->result);
    if (msg->front.iov_len != sizeof(*rhead) + object_len +
        numops * sizeof(struct ceph_osd_op))
        goto bad;
    dout("handle_reply %p tid %llu result %d\n", msg, tid, (int)result);
    /* 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 this connection filled our message, drop our reference now, to
     * avoid a (safe but slower) revoke later.
     */
    if (req->r_con_filling_msg == con && req->r_reply == msg) {
        dout(" dropping con_filling_msg ref %p\n", con);
        req->r_con_filling_msg = NULL;
        con->ops->put(con);
    }

    if (!req->r_got_reply) {
        unsigned int 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);
        mutex_unlock(&osdc->request_mutex);
        goto done;
    }

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

    if (req->r_linger && (flags & CEPH_OSD_FLAG_ONDISK))
        __register_linger_request(osdc, req);

    /* either this is a read, or we got the safe response */
    if (result < 0 ||
        (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_all(&req->r_completion);

    if (flags & CEPH_OSD_FLAG_ONDISK)
        complete_request(req);

done:
    dout("req=%p req->r_linger=%d\n", req, req->r_linger);
    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));
    ceph_msg_dump(msg);
}

static void reset_changed_osds(struct ceph_osd_client *osdc)
{
    struct rb_node *p, *n;

    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) ||
            memcmp(&osd->o_con.peer_addr,
               ceph_osd_addr(osdc->osdmap,
                     osd->o_osd),
               sizeof(struct ceph_entity_addr)) != 0)
            __reset_osd(osdc, osd);
    }
}

/*
 * Requeue requests whose mapping to an OSD has changed.  If requests map to
 * no osd, request a new map.
 *
 * Caller should hold map_sem for read and request_mutex.
 */
static void kick_requests(struct ceph_osd_client *osdc, int force_resend)
{
    struct ceph_osd_request *req, *nreq;
    struct rb_node *p;
    int needmap = 0;
    int err;

    dout("kick_requests %s\n", force_resend ? " (force resend)" : "");
    mutex_lock(&osdc->request_mutex);
    for (p = rb_first(&osdc->requests); p; ) {
        req = rb_entry(p, struct ceph_osd_request, r_node);
        p = rb_next(p);
        err = __map_request(osdc, req, force_resend);
        if (err < 0)
            continue;  /* error */
        if (req->r_osd == NULL) {
            dout("%p tid %llu maps to no osd\n", req, req->r_tid);
            needmap++;  /* request a newer map */
        } else if (err > 0) {
            if (!req->r_linger) {
                dout("%p tid %llu requeued on osd%d\n", req,
                     req->r_tid,
                     req->r_osd ? req->r_osd->o_osd : -1);
                req->r_flags |= CEPH_OSD_FLAG_RETRY;
            }
        }
        if (req->r_linger && list_empty(&req->r_linger_item)) {
            /*
             * register as a linger so that we will
             * re-submit below and get a new tid
             */
            dout("%p tid %llu restart on osd%d\n",
                 req, req->r_tid,
                 req->r_osd ? req->r_osd->o_osd : -1);
            __register_linger_request(osdc, req);
            __unregister_request(osdc, req);
        }
    }

    list_for_each_entry_safe(req, nreq, &osdc->req_linger,
                 r_linger_item) {
        dout("linger req=%p req->r_osd=%p\n", req, req->r_osd);

        err = __map_request(osdc, req, force_resend);
        if (err == 0)
            continue;  /* no change and no osd was specified */
        if (err < 0)
            continue;  /* hrm! */
        if (req->r_osd == NULL) {
            dout("tid %llu maps to no valid osd\n", req->r_tid);
            needmap++;  /* request a newer map */
            continue;
        }

        dout("kicking lingering %p tid %llu osd%d\n", req, req->r_tid,
             req->r_osd ? req->r_osd->o_osd : -1);
        __unregister_linger_request(osdc, req);
        __register_request(osdc, req);
    }
    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_check_fsid(osdc->client, &fsid) < 0)
        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);
        epoch = ceph_decode_32(&p);
        maplen = ceph_decode_32(&p);
        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;
            }
            BUG_ON(!newmap);
            if (newmap != osdc->osdmap) {
                ceph_osdmap_destroy(osdc->osdmap);
                osdc->osdmap = newmap;
            }
            kick_requests(osdc, 0);
            reset_changed_osds(osdc);
        } 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);
        epoch = ceph_decode_32(&p);
        maplen = ceph_decode_32(&p);
        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 {
            int skipped_map = 0;

            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;
            }
            BUG_ON(!newmap);
            oldmap = osdc->osdmap;
            osdc->osdmap = newmap;
            if (oldmap) {
                if (oldmap->epoch + 1 < newmap->epoch)
                    skipped_map = 1;
                ceph_osdmap_destroy(oldmap);
            }
            kick_requests(osdc, skipped_map);
        }
        p += maplen;
        nr_maps--;
    }

done:
    downgrade_write(&osdc->map_sem);
    ceph_monc_got_osdmap(&osdc->client->monc, osdc->osdmap->epoch);

    /*
     * subscribe to subsequent osdmap updates if full to ensure
     * we find out when we are no longer full and stop returning
     * ENOSPC.
     */
    if (ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_FULL))
        ceph_monc_request_next_osdmap(&osdc->client->monc);

    send_queued(osdc);
    up_read(&osdc->map_sem);
    wake_up_all(&osdc->client->auth_wq);
    return;

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

/*
 * watch/notify callback event infrastructure
 *
 * These callbacks are used both for watch and notify operations.
 */
static void __release_event(struct kref *kref)
{
    struct ceph_osd_event *event =
        container_of(kref, struct ceph_osd_event, kref);

    dout("__release_event %p\n", event);
    kfree(event);
}

static void get_event(struct ceph_osd_event *event)
{
    kref_get(&event->kref);
}

void ceph_osdc_put_event(struct ceph_osd_event *event)
{
    kref_put(&event->kref, __release_event);
}
EXPORT_SYMBOL(ceph_osdc_put_event);

static void __insert_event(struct ceph_osd_client *osdc,
                 struct ceph_osd_event *new)
{
    struct rb_node **p = &osdc->event_tree.rb_node;
    struct rb_node *parent = NULL;
    struct ceph_osd_event *event = NULL;

    while (*p) {
        parent = *p;
        event = rb_entry(parent, struct ceph_osd_event, node);
        if (new->cookie < event->cookie)
            p = &(*p)->rb_left;
        else if (new->cookie > event->cookie)
            p = &(*p)->rb_right;
        else
            BUG();
    }

    rb_link_node(&new->node, parent, p);
    rb_insert_color(&new->node, &osdc->event_tree);
}

static struct ceph_osd_event *__find_event(struct ceph_osd_client *osdc,
                            u64 cookie)
{
    struct rb_node **p = &osdc->event_tree.rb_node;
    struct rb_node *parent = NULL;
    struct ceph_osd_event *event = NULL;

    while (*p) {
        parent = *p;
        event = rb_entry(parent, struct ceph_osd_event, node);
        if (cookie < event->cookie)
            p = &(*p)->rb_left;
        else if (cookie > event->cookie)
            p = &(*p)->rb_right;
        else
            return event;
    }
    return NULL;
}

static void __remove_event(struct ceph_osd_event *event)
{
    struct ceph_osd_client *osdc = event->osdc;

    if (!RB_EMPTY_NODE(&event->node)) {
        dout("__remove_event removed %p\n", event);
        rb_erase(&event->node, &osdc->event_tree);
        ceph_osdc_put_event(event);
    } else {
        dout("__remove_event didn't remove %p\n", event);
    }
}

int ceph_osdc_create_event(struct ceph_osd_client *osdc,
               void (*event_cb)(u64, u64, u8, void *),
               int one_shot, void *data,
               struct ceph_osd_event **pevent)
{
    struct ceph_osd_event *event;

    event = kmalloc(sizeof(*event), GFP_NOIO);
    if (!event)
        return -ENOMEM;

    dout("create_event %p\n", event);
    event->cb = event_cb;
    event->one_shot = one_shot;
    event->data = data;
    event->osdc = osdc;
    INIT_LIST_HEAD(&event->osd_node);
    kref_init(&event->kref);   /* one ref for us */
    kref_get(&event->kref);    /* one ref for the caller */
    init_completion(&event->completion);

    spin_lock(&osdc->event_lock);
    event->cookie = ++osdc->event_count;
    __insert_event(osdc, event);
    spin_unlock(&osdc->event_lock);

    *pevent = event;
    return 0;
}
EXPORT_SYMBOL(ceph_osdc_create_event);

void ceph_osdc_cancel_event(struct ceph_osd_event *event)
{
    struct ceph_osd_client *osdc = event->osdc;

    dout("cancel_event %p\n", event);
    spin_lock(&osdc->event_lock);
    __remove_event(event);
    spin_unlock(&osdc->event_lock);
    ceph_osdc_put_event(event); /* caller's */
}
EXPORT_SYMBOL(ceph_osdc_cancel_event);


static void do_event_work(struct work_struct *work)
{
    struct ceph_osd_event_work *event_work =
        container_of(work, struct ceph_osd_event_work, work);
    struct ceph_osd_event *event = event_work->event;
    u64 ver = event_work->ver;
    u64 notify_id = event_work->notify_id;
    u8 opcode = event_work->opcode;

    dout("do_event_work completing %p\n", event);
    event->cb(ver, notify_id, opcode, event->data);
    complete(&event->completion);
    dout("do_event_work completed %p\n", event);
    ceph_osdc_put_event(event);
    kfree(event_work);
}


/*
 * Process osd watch notifications
 */
void handle_watch_notify(struct ceph_osd_client *osdc, struct ceph_msg *msg)
{
    void *p, *end;
    u8 proto_ver;
    u64 cookie, ver, notify_id;
    u8 opcode;
    struct ceph_osd_event *event;
    struct ceph_osd_event_work *event_work;

    p = msg->front.iov_base;
    end = p + msg->front.iov_len;

    ceph_decode_8_safe(&p, end, proto_ver, bad);
    ceph_decode_8_safe(&p, end, opcode, bad);
    ceph_decode_64_safe(&p, end, cookie, bad);
    ceph_decode_64_safe(&p, end, ver, bad);
    ceph_decode_64_safe(&p, end, notify_id, bad);

    spin_lock(&osdc->event_lock);
    event = __find_event(osdc, cookie);
    if (event) {
        get_event(event);
        if (event->one_shot)
            __remove_event(event);
    }
    spin_unlock(&osdc->event_lock);
    dout("handle_watch_notify cookie %lld ver %lld event %p\n",
         cookie, ver, event);
    if (event) {
        event_work = kmalloc(sizeof(*event_work), GFP_NOIO);
        if (!event_work) {
            dout("ERROR: could not allocate event_work\n");
            goto done_err;
        }
        INIT_WORK(&event_work->work, do_event_work);
        event_work->event = event;
        event_work->ver = ver;
        event_work->notify_id = notify_id;
        event_work->opcode = opcode;
        if (!queue_work(osdc->notify_wq, &event_work->work)) {
            dout("WARNING: failed to queue notify event work\n");
            goto done_err;
        }
    }

    return;

done_err:
    complete(&event->completion);
    ceph_osdc_put_event(event);
    return;

bad:
    pr_err("osdc handle_watch_notify corrupt msg\n");
    return;
}

int ceph_osdc_wait_event(struct ceph_osd_event *event, unsigned long timeout)
{
    int err;

    dout("wait_event %p\n", event);
    err = wait_for_completion_interruptible_timeout(&event->completion,
                            timeout * HZ);
    ceph_osdc_put_event(event);
    if (err > 0)
        err = 0;
    dout("wait_event %p returns %d\n", event, err);
    return err;
}
EXPORT_SYMBOL(ceph_osdc_wait_event);

/*
 * Register request, send initial attempt.
 */
int ceph_osdc_start_request(struct ceph_osd_client *osdc,
                struct ceph_osd_request *req,
                bool nofail)
{
    int rc = 0;

    req->r_request->pages = req->r_pages;
    req->r_request->nr_pages = req->r_num_pages;
#ifdef CONFIG_BLOCK
    req->r_request->bio = req->r_bio;
#endif
    req->r_request->trail = req->r_trail;

    register_request(osdc, req);

    down_read(&osdc->map_sem);
    mutex_lock(&osdc->request_mutex);
    /*
     * a racing kick_requests() may have sent the message for us
     * while we dropped request_mutex above, so only send now if
     * the request still han't been touched yet.
     */
    if (req->r_sent == 0) {
        rc = __map_request(osdc, req, 0);
        if (rc < 0) {
            if (nofail) {
                dout("osdc_start_request failed map, "
                     " will retry %lld\n", req->r_tid);
                rc = 0;
            }
            goto out_unlock;
        }
        if (req->r_osd == NULL) {
            dout("send_request %p no up osds in pg\n", req);
            ceph_monc_request_next_osdmap(&osdc->client->monc);
        } else {
            __send_request(osdc, req);
        }
        rc = 0;
    }

out_unlock:
    mutex_unlock(&osdc->request_mutex);
    up_read(&osdc->map_sem);
    return rc;
}
EXPORT_SYMBOL(ceph_osdc_start_request);

/*
 * 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);
        __unregister_request(osdc, req);
        mutex_unlock(&osdc->request_mutex);
        complete_request(req);
        dout("wait_request tid %llu canceled/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;
}
EXPORT_SYMBOL(ceph_osdc_wait_request);

/*
 * 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);
}
EXPORT_SYMBOL(ceph_osdc_sync);

/*
 * 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->last_tid = 0;
    osdc->osds = RB_ROOT;
    INIT_LIST_HEAD(&osdc->osd_lru);
    osdc->requests = RB_ROOT;
    INIT_LIST_HEAD(&osdc->req_lru);
    INIT_LIST_HEAD(&osdc->req_unsent);
    INIT_LIST_HEAD(&osdc->req_notarget);
    INIT_LIST_HEAD(&osdc->req_linger);
    osdc->num_requests = 0;
    INIT_DELAYED_WORK(&osdc->timeout_work, handle_timeout);
    INIT_DELAYED_WORK(&osdc->osds_timeout_work, handle_osds_timeout);
    spin_lock_init(&osdc->event_lock);
    osdc->event_tree = RB_ROOT;
    osdc->event_count = 0;

    schedule_delayed_work(&osdc->osds_timeout_work,
       round_jiffies_relative(osdc->client->options->osd_idle_ttl * HZ));

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

    err = ceph_msgpool_init(&osdc->msgpool_op, CEPH_MSG_OSD_OP,
                OSD_OP_FRONT_LEN, 10, true,
                "osd_op");
    if (err < 0)
        goto out_mempool;
    err = ceph_msgpool_init(&osdc->msgpool_op_reply, CEPH_MSG_OSD_OPREPLY,
                OSD_OPREPLY_FRONT_LEN, 10, true,
                "osd_op_reply");
    if (err < 0)
        goto out_msgpool;

    osdc->notify_wq = create_singlethread_workqueue("ceph-watch-notify");
    if (IS_ERR(osdc->notify_wq)) {
        err = PTR_ERR(osdc->notify_wq);
        osdc->notify_wq = NULL;
        goto out_msgpool;
    }
    return 0;

out_msgpool:
    ceph_msgpool_destroy(&osdc->msgpool_op);
out_mempool:
    mempool_destroy(osdc->req_mempool);
out:
    return err;
}
EXPORT_SYMBOL(ceph_osdc_init);

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

/*
 * 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, int page_align)
{
    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, page_align);
    if (IS_ERR(req))
        return PTR_ERR(req);

    /* it may be a short read due to an object boundary */
    req->r_pages = pages;

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

    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;
}
EXPORT_SYMBOL(ceph_osdc_readpages);

/*
 * 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;
    int page_align = off & ~PAGE_MASK;

    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, page_align);
    if (IS_ERR(req))
        return PTR_ERR(req);

    /* it may be a short write due to an object boundary */
    req->r_pages = pages;
    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;
}
EXPORT_SYMBOL(ceph_osdc_writepages);

/*
 * 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;
    int type = le16_to_cpu(msg->hdr.type);

    if (!osd)
        goto out;
    osdc = osd->o_osdc;

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

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

/*
 * lookup and return message for incoming reply.  set up reply message
 * pages.
 */
static struct ceph_msg *get_reply(struct ceph_connection *con,
                  struct ceph_msg_header *hdr,
                  int *skip)
{
    struct ceph_osd *osd = con->private;
    struct ceph_osd_client *osdc = osd->o_osdc;
    struct ceph_msg *m;
    struct ceph_osd_request *req;
    int front = le32_to_cpu(hdr->front_len);
    int data_len = le32_to_cpu(hdr->data_len);
    u64 tid;

    tid = le64_to_cpu(hdr->tid);
    mutex_lock(&osdc->request_mutex);
    req = __lookup_request(osdc, tid);
    if (!req) {
        *skip = 1;
        m = NULL;
        dout("get_reply unknown tid %llu from osd%d\n", tid,
             osd->o_osd);
        goto out;
    }

    if (req->r_con_filling_msg) {
        dout("%s revoking msg %p from old con %p\n", __func__,
             req->r_reply, req->r_con_filling_msg);
        ceph_msg_revoke_incoming(req->r_reply);
        req->r_con_filling_msg->ops->put(req->r_con_filling_msg);
        req->r_con_filling_msg = NULL;
    }

    if (front > req->r_reply->front.iov_len) {
        pr_warning("get_reply front %d > preallocated %d\n",
               front, (int)req->r_reply->front.iov_len);
        m = ceph_msg_new(CEPH_MSG_OSD_OPREPLY, front, GFP_NOFS, false);
        if (!m)
            goto out;
        ceph_msg_put(req->r_reply);
        req->r_reply = m;
    }
    m = ceph_msg_get(req->r_reply);

    if (data_len > 0) {
        int want = calc_pages_for(req->r_page_alignment, data_len);

        if (unlikely(req->r_num_pages < want)) {
            pr_warning("tid %lld reply has %d bytes %d pages, we"
                   " had only %d pages ready\n", tid, data_len,
                   want, req->r_num_pages);
            *skip = 1;
            ceph_msg_put(m);
            m = NULL;
            goto out;
        }
        m->pages = req->r_pages;
        m->nr_pages = req->r_num_pages;
        m->page_alignment = req->r_page_alignment;
#ifdef CONFIG_BLOCK
        m->bio = req->r_bio;
#endif
    }
    *skip = 0;
    req->r_con_filling_msg = con->ops->get(con);
    dout("get_reply tid %lld %p\n", tid, m);

out:
    mutex_unlock(&osdc->request_mutex);
    return m;

}

static struct ceph_msg *alloc_msg(struct ceph_connection *con,
                  struct ceph_msg_header *hdr,
                  int *skip)
{
    struct ceph_osd *osd = con->private;
    int type = le16_to_cpu(hdr->type);
    int front = le32_to_cpu(hdr->front_len);

    *skip = 0;
    switch (type) {
    case CEPH_MSG_OSD_MAP:
    case CEPH_MSG_WATCH_NOTIFY:
        return ceph_msg_new(type, front, GFP_NOFS, false);
    case CEPH_MSG_OSD_OPREPLY:
        return get_reply(con, hdr, skip);
    default:
        pr_info("alloc_msg unexpected msg type %d from osd%d\n", type,
            osd->o_osd);
        *skip = 1;
        return NULL;
    }
}

/*
 * 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);
}

/*
 * authentication
 */
/*
 * Note: returned pointer is the address of a structure that's
 * managed separately.  Caller must *not* attempt to free it.
 */
static struct ceph_auth_handshake *get_authorizer(struct ceph_connection *con,
                    int *proto, int force_new)
{
    struct ceph_osd *o = con->private;
    struct ceph_osd_client *osdc = o->o_osdc;
    struct ceph_auth_client *ac = osdc->client->monc.auth;
    struct ceph_auth_handshake *auth = &o->o_auth;

    if (force_new && auth->authorizer) {
        if (ac->ops && ac->ops->destroy_authorizer)
            ac->ops->destroy_authorizer(ac, auth->authorizer);
        auth->authorizer = NULL;
    }
    if (!auth->authorizer && ac->ops && ac->ops->create_authorizer) {
        int ret = ac->ops->create_authorizer(ac, CEPH_ENTITY_TYPE_OSD,
                            auth);
        if (ret)
            return ERR_PTR(ret);
    }
    *proto = ac->protocol;

    return auth;
}


static int verify_authorizer_reply(struct ceph_connection *con, int len)
{
    struct ceph_osd *o = con->private;
    struct ceph_osd_client *osdc = o->o_osdc;
    struct ceph_auth_client *ac = osdc->client->monc.auth;

    /*
     * XXX If ac->ops or ac->ops->verify_authorizer_reply is null,
     * XXX which do we do:  succeed or fail?
     */
    return ac->ops->verify_authorizer_reply(ac, o->o_auth.authorizer, len);
}

static int invalidate_authorizer(struct ceph_connection *con)
{
    struct ceph_osd *o = con->private;
    struct ceph_osd_client *osdc = o->o_osdc;
    struct ceph_auth_client *ac = osdc->client->monc.auth;

    if (ac->ops && ac->ops->invalidate_authorizer)
        ac->ops->invalidate_authorizer(ac, CEPH_ENTITY_TYPE_OSD);

    return ceph_monc_validate_auth(&osdc->client->monc);
}

static const struct ceph_connection_operations osd_con_ops = {
    .get = get_osd_con,
    .put = put_osd_con,
    .dispatch = dispatch,
    .get_authorizer = get_authorizer,
    .verify_authorizer_reply = verify_authorizer_reply,
    .invalidate_authorizer = invalidate_authorizer,
    .alloc_msg = alloc_msg,
    .fault = osd_reset,
};