#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 int __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);
  }

  void 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 */
  
  	reqhead->snapid = cpu_to_le64(snapid);
  
  	/* 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
  ",

  		     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)
  ",
  	     *bno, objoff, objlen, req->r_num_pages);
  
  }

  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 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_req_op *op)

  {

  	u64 bno;

  	ceph_calc_raw_layout(osdc, layout, vino.snap, off,
  			     plen, &bno, req, op);

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

  	req->r_oid_len = strlen(req->r_oid);

  }

  /*
   * 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_reply)
  		ceph_msg_put(req->r_reply);

  	if (req->r_con_filling_msg) {

  		dout("release_request revoking pages %p from con %p
  ",

  		     req->r_pages, req->r_con_filling_msg);
  		ceph_con_revoke_message(req->r_con_filling_msg,
  				      req->r_reply);
  		ceph_con_put(req->r_con_filling_msg);

  	}

  	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);

  	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);

  	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 += 40;
  	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);

  	if (!msg) {

  		ceph_osdc_put_request(req);

  		return NULL;

  	}

  	msg->hdr.type = cpu_to_le16(CEPH_MSG_OSD_OP);
  	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 (dst->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
  ", 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;
  
  	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 NULL;

  
  	/* calculate max write size */

  	calc_layout(osdc, vino, layout, off, plen, req, ops);

  	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
  ", 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
  ", 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
  ", 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
  ", 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)
  {
  	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);

  	INIT_LIST_HEAD(&osd->o_linger_requests);

  	INIT_LIST_HEAD(&osd->o_osd_lru);

  	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;

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

  	if (atomic_dec_and_test(&osd->o_ref)) {
  		struct ceph_auth_client *ac = osd->o_osdc->client->monc.auth;
  
  		if (osd->o_authorizer)
  			ac->ops->destroy_authorizer(ac, osd->o_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
  ", 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("__remove_old_osds %p
  ", 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
  ", 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
  ", 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
  ", 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
  ", 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, &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
  ", 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
  ", 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
  ");
  		__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)
  {
  	dout("__unregister_request %p tid %lld
  ", 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_con_revoke(&req->r_osd->o_con, 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
  ", 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
  ");
  		__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_con_revoke(&req->r_osd->o_con, 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
  ", req);
  	list_add_tail(&req->r_linger_item, &osdc->req_linger);
  	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
  ", 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
  ", 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
  ", 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)

  {
  	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
  ", 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 ((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)
  ",

  	     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);

  		if (!req->r_osd) {
  			list_move(&req->r_req_lru_item, &osdc->req_notarget);

  			goto out;

  		}

  		dout("map_request osd %p is osd%d
  ", 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) {
  		__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 int __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
  ",
  	     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;
  	return 0;
  }
  
  /*

   * 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
  ");
  	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
  ");
  	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
  ",
  			   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
  ",

  		     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
  ");
  	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
  ", msg, tid, (int)result);

  	/* lookup */
  	mutex_lock(&osdc->request_mutex);
  	req = __lookup_request(osdc, tid);
  	if (req == NULL) {
  		dout("handle_reply tid %llu dne
  ", 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
  ", con);

  		req->r_con_filling_msg = NULL;

  		ceph_con_put(con);
  	}

  	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
  ", 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
  ", tid);

  		mutex_unlock(&osdc->request_mutex);

  		goto done;
  	}
  
  	dout("handle_reply tid %llu flags %d
  ", 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
  ", req, req->r_linger);

  	ceph_osdc_put_request(req);
  	return;
  
  bad:
  	pr_err("corrupt osd_op_reply got %d %d expected %d
  ",
  	       (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)

  {

  	struct ceph_osd_request *req, *nreq;

  	struct rb_node *p;
  	int needmap = 0;
  	int err;

  	dout("kick_requests
  ");

  	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);
  		err = __map_request(osdc, req);
  		if (err < 0)
  			continue;  /* error */
  		if (req->r_osd == NULL) {
  			dout("%p tid %llu maps to no osd
  ", req, req->r_tid);
  			needmap++;  /* request a newer map */
  		} else if (err > 0) {
  			dout("%p tid %llu requeued on osd%d
  ", req, req->r_tid,
  			     req->r_osd ? req->r_osd->o_osd : -1);

  			if (!req->r_linger)
  				req->r_flags |= CEPH_OSD_FLAG_RETRY;
  		}
  	}
  
  	list_for_each_entry_safe(req, nreq, &osdc->req_linger,
  				 r_linger_item) {
  		dout("linger req=%p req->r_osd=%p
  ", req, req->r_osd);
  
  		err = __map_request(osdc, req);
  		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
  ", req->r_tid);
  			needmap++;  /* request a newer map */
  			continue;

  		}

  
  		dout("kicking lingering %p tid %llu osd%d
  ", 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
  ", 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
  ", 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
  ", 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
  ",
  			     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);
  			reset_changed_osds(osdc);

  		} else {
  			dout("ignoring incremental map %u len %d
  ",
  			     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
  ", 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
  ",
  			     epoch, maplen);
  		} else if (osdc->osdmap && osdc->osdmap->epoch >= epoch) {
  			dout("skipping full map %u len %d, "
  			     "older than our %u
  ", epoch, maplen,
  			     osdc->osdmap->epoch);
  		} else {
  			dout("taking full map %u len %d
  ", 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)
  				ceph_osdmap_destroy(oldmap);

  			kick_requests(osdc);

  		}
  		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
  ");

  	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
  ", 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
  ", event);
  		rb_erase(&event->node, &osdc->event_tree);
  		ceph_osdc_put_event(event);
  	} else {
  		dout("__remove_event didn't remove %p
  ", 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
  ", 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
  ", 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
  ", event);
  	event->cb(ver, notify_id, opcode, event->data);
  	complete(&event->completion);
  	dout("do_event_work completed %p
  ", 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
  ",
  	     cookie, ver, event);
  	if (event) {
  		event_work = kmalloc(sizeof(*event_work), GFP_NOIO);

  		if (!event_work) {
  			dout("ERROR: could not allocate event_work
  ");
  			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
  ");
  			goto done_err;
  		}
  	}
  
  	return;
  
  done_err:
  	complete(&event->completion);
  	ceph_osdc_put_event(event);
  	return;
  
  bad:
  	pr_err("osdc handle_watch_notify corrupt msg
  ");
  	return;
  }
  
  int ceph_osdc_wait_event(struct ceph_osd_event *event, unsigned long timeout)
  {
  	int err;
  
  	dout("wait_event %p
  ", 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
  ", 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);

  		if (rc < 0) {
  			if (nofail) {
  				dout("osdc_start_request failed map, "
  				     " will retry %lld
  ", req->r_tid);
  				rc = 0;
  			}

  			goto out_unlock;

  		}

  		if (req->r_osd == NULL) {
  			dout("send_request %p no up osds in pg
  ", req);
  			ceph_monc_request_next_osdmap(&osdc->client->monc);
  		} else {
  			rc = __send_request(osdc, req);
  			if (rc) {
  				if (nofail) {
  					dout("osdc_start_request failed send, "
  					     " will retry %lld
  ", req->r_tid);
  					rc = 0;
  				} else {
  					__unregister_request(osdc, req);
  				}

  			}

  		}
  	}

  
  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
  ", req->r_tid);

  		return rc;
  	}
  
  	dout("wait_request tid %llu result %d
  ", 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)
  ",
  		     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)
  ", 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
  ");
  	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, OSD_OP_FRONT_LEN, 10, true,
  				"osd_op");

  	if (err < 0)

  		goto out_mempool;

  	err = ceph_msgpool_init(&osdc->msgpool_op_reply,

  				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
  ", 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 (!req)
  		return -ENOMEM;

  
  	/* 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)
  ",
  	     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
  ", 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 (!req)
  		return -ENOMEM;

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

  	dout("writepages %llu~%llu (%d pages)
  ", 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
  ", 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
  ", 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;

  		pr_info("get_reply unknown tid %llu from osd%d
  ", tid,

  			osd->o_osd);

  		goto out;
  	}

  
  	if (req->r_con_filling_msg) {
  		dout("get_reply revoking msg %p from old con %p
  ",
  		     req->r_reply, req->r_con_filling_msg);
  		ceph_con_revoke_message(req->r_con_filling_msg, req->r_reply);
  		ceph_con_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
  ",
  			   front, (int)req->r_reply->front.iov_len);

  		m = ceph_msg_new(CEPH_MSG_OSD_OPREPLY, front, GFP_NOFS);

  		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
  ", 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 = ceph_con_get(con);
  	dout("get_reply tid %lld %p
  ", 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);
  
  	switch (type) {
  	case CEPH_MSG_OSD_MAP:

  	case CEPH_MSG_WATCH_NOTIFY:

  		return ceph_msg_new(type, front, GFP_NOFS);

  	case CEPH_MSG_OSD_OPREPLY:
  		return get_reply(con, hdr, skip);
  	default:
  		pr_info("alloc_msg unexpected msg type %d from osd%d
  ", 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
   */
  static int get_authorizer(struct ceph_connection *con,

  			  void **buf, int *len, int *proto,
  			  void **reply_buf, int *reply_len, 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;
  	int ret = 0;
  
  	if (force_new && o->o_authorizer) {
  		ac->ops->destroy_authorizer(ac, o->o_authorizer);
  		o->o_authorizer = NULL;
  	}
  	if (o->o_authorizer == NULL) {
  		ret = ac->ops->create_authorizer(
  			ac, CEPH_ENTITY_TYPE_OSD,
  			&o->o_authorizer,
  			&o->o_authorizer_buf,
  			&o->o_authorizer_buf_len,
  			&o->o_authorizer_reply_buf,
  			&o->o_authorizer_reply_buf_len);
  		if (ret)

  			return ret;

  	}
  
  	*proto = ac->protocol;
  	*buf = o->o_authorizer_buf;
  	*len = o->o_authorizer_buf_len;
  	*reply_buf = o->o_authorizer_reply_buf;
  	*reply_len = o->o_authorizer_reply_buf_len;
  	return 0;
  }
  
  
  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;
  
  	return ac->ops->verify_authorizer_reply(ac, o->o_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->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,

  };