net/ceph/osd_client.c

// SPDX-License-Identifier: GPL-2.0

#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/ceph_features.h>
#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>
#include <linux/ceph/striper.h>

#define OSD_OPREPLY_FRONT_LEN	512

static struct kmem_cache	*ceph_osd_request_cache;

static const struct ceph_connection_operations osd_con_ops;

/*
 * 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.
 */

static void link_request(struct ceph_osd *osd, struct ceph_osd_request *req);
static void unlink_request(struct ceph_osd *osd, struct ceph_osd_request *req);
static void link_linger(struct ceph_osd *osd,
			struct ceph_osd_linger_request *lreq);
static void unlink_linger(struct ceph_osd *osd,
			  struct ceph_osd_linger_request *lreq);
static void clear_backoffs(struct ceph_osd *osd);

#if 1
static inline bool rwsem_is_wrlocked(struct rw_semaphore *sem)
{
	bool wrlocked = true;

	if (unlikely(down_read_trylock(sem))) {
		wrlocked = false;
		up_read(sem);
	}

	return wrlocked;
}
static inline void verify_osdc_locked(struct ceph_osd_client *osdc)
{
	WARN_ON(!rwsem_is_locked(&osdc->lock));
}
static inline void verify_osdc_wrlocked(struct ceph_osd_client *osdc)
{
	WARN_ON(!rwsem_is_wrlocked(&osdc->lock));
}
static inline void verify_osd_locked(struct ceph_osd *osd)
{
	struct ceph_osd_client *osdc = osd->o_osdc;

	WARN_ON(!(mutex_is_locked(&osd->lock) &&
		  rwsem_is_locked(&osdc->lock)) &&
		!rwsem_is_wrlocked(&osdc->lock));
}
static inline void verify_lreq_locked(struct ceph_osd_linger_request *lreq)
{
	WARN_ON(!mutex_is_locked(&lreq->lock));
}
#else
static inline void verify_osdc_locked(struct ceph_osd_client *osdc) { }
static inline void verify_osdc_wrlocked(struct ceph_osd_client *osdc) { }
static inline void verify_osd_locked(struct ceph_osd *osd) { }
static inline void verify_lreq_locked(struct ceph_osd_linger_request *lreq) { }
#endif

/*
 * 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_file_layout *layout, u64 off, u64 *plen,
			u64 *objnum, u64 *objoff, u64 *objlen)
{
	u64 orig_len = *plen;
	u32 xlen;

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

	dout("calc_layout objnum=%llx %llu~%llu\n", *objnum, *objoff, *objlen);
	return 0;
}

static void ceph_osd_data_init(struct ceph_osd_data *osd_data)
{
	memset(osd_data, 0, sizeof (*osd_data));
	osd_data->type = CEPH_OSD_DATA_TYPE_NONE;
}

static void ceph_osd_data_pages_init(struct ceph_osd_data *osd_data,
			struct page **pages, u64 length, u32 alignment,
			bool pages_from_pool, bool own_pages)
{
	osd_data->type = CEPH_OSD_DATA_TYPE_PAGES;
	osd_data->pages = pages;
	osd_data->length = length;
	osd_data->alignment = alignment;
	osd_data->pages_from_pool = pages_from_pool;
	osd_data->own_pages = own_pages;
}

static void ceph_osd_data_pagelist_init(struct ceph_osd_data *osd_data,
			struct ceph_pagelist *pagelist)
{
	osd_data->type = CEPH_OSD_DATA_TYPE_PAGELIST;
	osd_data->pagelist = pagelist;
}

#ifdef CONFIG_BLOCK
static void ceph_osd_data_bio_init(struct ceph_osd_data *osd_data,
				   struct ceph_bio_iter *bio_pos,
				   u32 bio_length)
{
	osd_data->type = CEPH_OSD_DATA_TYPE_BIO;
	osd_data->bio_pos = *bio_pos;
	osd_data->bio_length = bio_length;
}
#endif /* CONFIG_BLOCK */

static void ceph_osd_data_bvecs_init(struct ceph_osd_data *osd_data,
				     struct ceph_bvec_iter *bvec_pos,
				     u32 num_bvecs)
{
	osd_data->type = CEPH_OSD_DATA_TYPE_BVECS;
	osd_data->bvec_pos = *bvec_pos;
	osd_data->num_bvecs = num_bvecs;
}

#define osd_req_op_data(oreq, whch, typ, fld)				\
({									\
	struct ceph_osd_request *__oreq = (oreq);			\
	unsigned int __whch = (whch);					\
	BUG_ON(__whch >= __oreq->r_num_ops);				\
	&__oreq->r_ops[__whch].typ.fld;					\
})

static struct ceph_osd_data *
osd_req_op_raw_data_in(struct ceph_osd_request *osd_req, unsigned int which)
{
	BUG_ON(which >= osd_req->r_num_ops);

	return &osd_req->r_ops[which].raw_data_in;
}

struct ceph_osd_data *
osd_req_op_extent_osd_data(struct ceph_osd_request *osd_req,
			unsigned int which)
{
	return osd_req_op_data(osd_req, which, extent, osd_data);
}
EXPORT_SYMBOL(osd_req_op_extent_osd_data);

void osd_req_op_raw_data_in_pages(struct ceph_osd_request *osd_req,
			unsigned int which, struct page **pages,
			u64 length, u32 alignment,
			bool pages_from_pool, bool own_pages)
{
	struct ceph_osd_data *osd_data;

	osd_data = osd_req_op_raw_data_in(osd_req, which);
	ceph_osd_data_pages_init(osd_data, pages, length, alignment,
				pages_from_pool, own_pages);
}
EXPORT_SYMBOL(osd_req_op_raw_data_in_pages);

void osd_req_op_extent_osd_data_pages(struct ceph_osd_request *osd_req,
			unsigned int which, struct page **pages,
			u64 length, u32 alignment,
			bool pages_from_pool, bool own_pages)
{
	struct ceph_osd_data *osd_data;

	osd_data = osd_req_op_data(osd_req, which, extent, osd_data);
	ceph_osd_data_pages_init(osd_data, pages, length, alignment,
				pages_from_pool, own_pages);
}
EXPORT_SYMBOL(osd_req_op_extent_osd_data_pages);

void osd_req_op_extent_osd_data_pagelist(struct ceph_osd_request *osd_req,
			unsigned int which, struct ceph_pagelist *pagelist)
{
	struct ceph_osd_data *osd_data;

	osd_data = osd_req_op_data(osd_req, which, extent, osd_data);
	ceph_osd_data_pagelist_init(osd_data, pagelist);
}
EXPORT_SYMBOL(osd_req_op_extent_osd_data_pagelist);

#ifdef CONFIG_BLOCK
void osd_req_op_extent_osd_data_bio(struct ceph_osd_request *osd_req,
				    unsigned int which,
				    struct ceph_bio_iter *bio_pos,
				    u32 bio_length)
{
	struct ceph_osd_data *osd_data;

	osd_data = osd_req_op_data(osd_req, which, extent, osd_data);
	ceph_osd_data_bio_init(osd_data, bio_pos, bio_length);
}
EXPORT_SYMBOL(osd_req_op_extent_osd_data_bio);
#endif /* CONFIG_BLOCK */

void osd_req_op_extent_osd_data_bvecs(struct ceph_osd_request *osd_req,
				      unsigned int which,
				      struct bio_vec *bvecs, u32 num_bvecs,
				      u32 bytes)
{
	struct ceph_osd_data *osd_data;
	struct ceph_bvec_iter it = {
		.bvecs = bvecs,
		.iter = { .bi_size = bytes },
	};

	osd_data = osd_req_op_data(osd_req, which, extent, osd_data);
	ceph_osd_data_bvecs_init(osd_data, &it, num_bvecs);
}
EXPORT_SYMBOL(osd_req_op_extent_osd_data_bvecs);

void osd_req_op_extent_osd_data_bvec_pos(struct ceph_osd_request *osd_req,
					 unsigned int which,
					 struct ceph_bvec_iter *bvec_pos)
{
	struct ceph_osd_data *osd_data;

	osd_data = osd_req_op_data(osd_req, which, extent, osd_data);
	ceph_osd_data_bvecs_init(osd_data, bvec_pos, 0);
}
EXPORT_SYMBOL(osd_req_op_extent_osd_data_bvec_pos);

static void osd_req_op_cls_request_info_pagelist(
			struct ceph_osd_request *osd_req,
			unsigned int which, struct ceph_pagelist *pagelist)
{
	struct ceph_osd_data *osd_data;

	osd_data = osd_req_op_data(osd_req, which, cls, request_info);
	ceph_osd_data_pagelist_init(osd_data, pagelist);
}

void osd_req_op_cls_request_data_pagelist(
			struct ceph_osd_request *osd_req,
			unsigned int which, struct ceph_pagelist *pagelist)
{
	struct ceph_osd_data *osd_data;

	osd_data = osd_req_op_data(osd_req, which, cls, request_data);
	ceph_osd_data_pagelist_init(osd_data, pagelist);
	osd_req->r_ops[which].cls.indata_len += pagelist->length;
	osd_req->r_ops[which].indata_len += pagelist->length;
}
EXPORT_SYMBOL(osd_req_op_cls_request_data_pagelist);

void osd_req_op_cls_request_data_pages(struct ceph_osd_request *osd_req,
			unsigned int which, struct page **pages, u64 length,
			u32 alignment, bool pages_from_pool, bool own_pages)
{
	struct ceph_osd_data *osd_data;

	osd_data = osd_req_op_data(osd_req, which, cls, request_data);
	ceph_osd_data_pages_init(osd_data, pages, length, alignment,
				pages_from_pool, own_pages);
	osd_req->r_ops[which].cls.indata_len += length;
	osd_req->r_ops[which].indata_len += length;
}
EXPORT_SYMBOL(osd_req_op_cls_request_data_pages);

void osd_req_op_cls_request_data_bvecs(struct ceph_osd_request *osd_req,
				       unsigned int which,
				       struct bio_vec *bvecs, u32 num_bvecs,
				       u32 bytes)
{
	struct ceph_osd_data *osd_data;
	struct ceph_bvec_iter it = {
		.bvecs = bvecs,
		.iter = { .bi_size = bytes },
	};

	osd_data = osd_req_op_data(osd_req, which, cls, request_data);
	ceph_osd_data_bvecs_init(osd_data, &it, num_bvecs);
	osd_req->r_ops[which].cls.indata_len += bytes;
	osd_req->r_ops[which].indata_len += bytes;
}
EXPORT_SYMBOL(osd_req_op_cls_request_data_bvecs);

void osd_req_op_cls_response_data_pages(struct ceph_osd_request *osd_req,
			unsigned int which, struct page **pages, u64 length,
			u32 alignment, bool pages_from_pool, bool own_pages)
{
	struct ceph_osd_data *osd_data;

	osd_data = osd_req_op_data(osd_req, which, cls, response_data);
	ceph_osd_data_pages_init(osd_data, pages, length, alignment,
				pages_from_pool, own_pages);
}
EXPORT_SYMBOL(osd_req_op_cls_response_data_pages);

static u64 ceph_osd_data_length(struct ceph_osd_data *osd_data)
{
	switch (osd_data->type) {
	case CEPH_OSD_DATA_TYPE_NONE:
		return 0;
	case CEPH_OSD_DATA_TYPE_PAGES:
		return osd_data->length;
	case CEPH_OSD_DATA_TYPE_PAGELIST:
		return (u64)osd_data->pagelist->length;
#ifdef CONFIG_BLOCK
	case CEPH_OSD_DATA_TYPE_BIO:
		return (u64)osd_data->bio_length;
#endif /* CONFIG_BLOCK */
	case CEPH_OSD_DATA_TYPE_BVECS:
		return osd_data->bvec_pos.iter.bi_size;
	default:
		WARN(true, "unrecognized data type %d\n", (int)osd_data->type);
		return 0;
	}
}

static void ceph_osd_data_release(struct ceph_osd_data *osd_data)
{
	if (osd_data->type == CEPH_OSD_DATA_TYPE_PAGES && osd_data->own_pages) {
		int num_pages;

		num_pages = calc_pages_for((u64)osd_data->alignment,
						(u64)osd_data->length);
		ceph_release_page_vector(osd_data->pages, num_pages);
	}
	ceph_osd_data_init(osd_data);
}

static void osd_req_op_data_release(struct ceph_osd_request *osd_req,
			unsigned int which)
{
	struct ceph_osd_req_op *op;

	BUG_ON(which >= osd_req->r_num_ops);
	op = &osd_req->r_ops[which];

	switch (op->op) {
	case CEPH_OSD_OP_READ:
	case CEPH_OSD_OP_WRITE:
	case CEPH_OSD_OP_WRITEFULL:
		ceph_osd_data_release(&op->extent.osd_data);
		break;
	case CEPH_OSD_OP_CALL:
		ceph_osd_data_release(&op->cls.request_info);
		ceph_osd_data_release(&op->cls.request_data);
		ceph_osd_data_release(&op->cls.response_data);
		break;
	case CEPH_OSD_OP_SETXATTR:
	case CEPH_OSD_OP_CMPXATTR:
		ceph_osd_data_release(&op->xattr.osd_data);
		break;
	case CEPH_OSD_OP_STAT:
		ceph_osd_data_release(&op->raw_data_in);
		break;
	case CEPH_OSD_OP_NOTIFY_ACK:
		ceph_osd_data_release(&op->notify_ack.request_data);
		break;
	case CEPH_OSD_OP_NOTIFY:
		ceph_osd_data_release(&op->notify.request_data);
		ceph_osd_data_release(&op->notify.response_data);
		break;
	case CEPH_OSD_OP_LIST_WATCHERS:
		ceph_osd_data_release(&op->list_watchers.response_data);
		break;
	default:
		break;
	}
}

/*
 * Assumes @t is zero-initialized.
 */
static void target_init(struct ceph_osd_request_target *t)
{
	ceph_oid_init(&t->base_oid);
	ceph_oloc_init(&t->base_oloc);
	ceph_oid_init(&t->target_oid);
	ceph_oloc_init(&t->target_oloc);

	ceph_osds_init(&t->acting);
	ceph_osds_init(&t->up);
	t->size = -1;
	t->min_size = -1;

	t->osd = CEPH_HOMELESS_OSD;
}

static void target_copy(struct ceph_osd_request_target *dest,
			const struct ceph_osd_request_target *src)
{
	ceph_oid_copy(&dest->base_oid, &src->base_oid);
	ceph_oloc_copy(&dest->base_oloc, &src->base_oloc);
	ceph_oid_copy(&dest->target_oid, &src->target_oid);
	ceph_oloc_copy(&dest->target_oloc, &src->target_oloc);

	dest->pgid = src->pgid; /* struct */
	dest->spgid = src->spgid; /* struct */
	dest->pg_num = src->pg_num;
	dest->pg_num_mask = src->pg_num_mask;
	ceph_osds_copy(&dest->acting, &src->acting);
	ceph_osds_copy(&dest->up, &src->up);
	dest->size = src->size;
	dest->min_size = src->min_size;
	dest->sort_bitwise = src->sort_bitwise;

	dest->flags = src->flags;
	dest->paused = src->paused;

	dest->epoch = src->epoch;
	dest->last_force_resend = src->last_force_resend;

	dest->osd = src->osd;
}

static void target_destroy(struct ceph_osd_request_target *t)
{
	ceph_oid_destroy(&t->base_oid);
	ceph_oloc_destroy(&t->base_oloc);
	ceph_oid_destroy(&t->target_oid);
	ceph_oloc_destroy(&t->target_oloc);
}

/*
 * requests
 */
static void request_release_checks(struct ceph_osd_request *req)
{
	WARN_ON(!RB_EMPTY_NODE(&req->r_node));
	WARN_ON(!RB_EMPTY_NODE(&req->r_mc_node));
	WARN_ON(!list_empty(&req->r_unsafe_item));
	WARN_ON(req->r_osd);
}

static void ceph_osdc_release_request(struct kref *kref)
{
	struct ceph_osd_request *req = container_of(kref,
					    struct ceph_osd_request, r_kref);
	unsigned int which;

	dout("%s %p (r_request %p r_reply %p)\n", __func__, req,
	     req->r_request, req->r_reply);
	request_release_checks(req);

	if (req->r_request)
		ceph_msg_put(req->r_request);
	if (req->r_reply)
		ceph_msg_put(req->r_reply);

	for (which = 0; which < req->r_num_ops; which++)
		osd_req_op_data_release(req, which);

	target_destroy(&req->r_t);
	ceph_put_snap_context(req->r_snapc);

	if (req->r_mempool)
		mempool_free(req, req->r_osdc->req_mempool);
	else if (req->r_num_ops <= CEPH_OSD_SLAB_OPS)
		kmem_cache_free(ceph_osd_request_cache, req);
	else
		kfree(req);
}

void ceph_osdc_get_request(struct ceph_osd_request *req)
{
	dout("%s %p (was %d)\n", __func__, req,
	     kref_read(&req->r_kref));
	kref_get(&req->r_kref);
}
EXPORT_SYMBOL(ceph_osdc_get_request);

void ceph_osdc_put_request(struct ceph_osd_request *req)
{
	if (req) {
		dout("%s %p (was %d)\n", __func__, req,
		     kref_read(&req->r_kref));
		kref_put(&req->r_kref, ceph_osdc_release_request);
	}
}
EXPORT_SYMBOL(ceph_osdc_put_request);

static void request_init(struct ceph_osd_request *req)
{
	/* req only, each op is zeroed in _osd_req_op_init() */
	memset(req, 0, sizeof(*req));

	kref_init(&req->r_kref);
	init_completion(&req->r_completion);
	RB_CLEAR_NODE(&req->r_node);
	RB_CLEAR_NODE(&req->r_mc_node);
	INIT_LIST_HEAD(&req->r_unsafe_item);

	target_init(&req->r_t);
}

/*
 * This is ugly, but it allows us to reuse linger registration and ping
 * requests, keeping the structure of the code around send_linger{_ping}()
 * reasonable.  Setting up a min_nr=2 mempool for each linger request
 * and dealing with copying ops (this blasts req only, watch op remains
 * intact) isn't any better.
 */
static void request_reinit(struct ceph_osd_request *req)
{
	struct ceph_osd_client *osdc = req->r_osdc;
	bool mempool = req->r_mempool;
	unsigned int num_ops = req->r_num_ops;
	u64 snapid = req->r_snapid;
	struct ceph_snap_context *snapc = req->r_snapc;
	bool linger = req->r_linger;
	struct ceph_msg *request_msg = req->r_request;
	struct ceph_msg *reply_msg = req->r_reply;

	dout("%s req %p\n", __func__, req);
	WARN_ON(kref_read(&req->r_kref) != 1);
	request_release_checks(req);

	WARN_ON(kref_read(&request_msg->kref) != 1);
	WARN_ON(kref_read(&reply_msg->kref) != 1);
	target_destroy(&req->r_t);

	request_init(req);
	req->r_osdc = osdc;
	req->r_mempool = mempool;
	req->r_num_ops = num_ops;
	req->r_snapid = snapid;
	req->r_snapc = snapc;
	req->r_linger = linger;
	req->r_request = request_msg;
	req->r_reply = reply_msg;
}

struct ceph_osd_request *ceph_osdc_alloc_request(struct ceph_osd_client *osdc,
					       struct ceph_snap_context *snapc,
					       unsigned int num_ops,
					       bool use_mempool,
					       gfp_t gfp_flags)
{
	struct ceph_osd_request *req;

	if (use_mempool) {
		BUG_ON(num_ops > CEPH_OSD_SLAB_OPS);
		req = mempool_alloc(osdc->req_mempool, gfp_flags);
	} else if (num_ops <= CEPH_OSD_SLAB_OPS) {
		req = kmem_cache_alloc(ceph_osd_request_cache, gfp_flags);
	} else {
		BUG_ON(num_ops > CEPH_OSD_MAX_OPS);
		req = kmalloc(struct_size(req, r_ops, num_ops), gfp_flags);
	}
	if (unlikely(!req))
		return NULL;

	request_init(req);
	req->r_osdc = osdc;
	req->r_mempool = use_mempool;
	req->r_num_ops = num_ops;
	req->r_snapid = CEPH_NOSNAP;
	req->r_snapc = ceph_get_snap_context(snapc);

	dout("%s req %p\n", __func__, req);
	return req;
}
EXPORT_SYMBOL(ceph_osdc_alloc_request);

static int ceph_oloc_encoding_size(const struct ceph_object_locator *oloc)
{
	return 8 + 4 + 4 + 4 + (oloc->pool_ns ? oloc->pool_ns->len : 0);
}

int ceph_osdc_alloc_messages(struct ceph_osd_request *req, gfp_t gfp)
{
	struct ceph_osd_client *osdc = req->r_osdc;
	struct ceph_msg *msg;
	int msg_size;

	WARN_ON(ceph_oid_empty(&req->r_base_oid));
	WARN_ON(ceph_oloc_empty(&req->r_base_oloc));

	/* create request message */
	msg_size = CEPH_ENCODING_START_BLK_LEN +
			CEPH_PGID_ENCODING_LEN + 1; /* spgid */
	msg_size += 4 + 4 + 4; /* hash, osdmap_epoch, flags */
	msg_size += CEPH_ENCODING_START_BLK_LEN +
			sizeof(struct ceph_osd_reqid); /* reqid */
	msg_size += sizeof(struct ceph_blkin_trace_info); /* trace */
	msg_size += 4 + sizeof(struct ceph_timespec); /* client_inc, mtime */
	msg_size += CEPH_ENCODING_START_BLK_LEN +
			ceph_oloc_encoding_size(&req->r_base_oloc); /* oloc */
	msg_size += 4 + req->r_base_oid.name_len; /* oid */
	msg_size += 2 + req->r_num_ops * sizeof(struct ceph_osd_op);
	msg_size += 8; /* snapid */
	msg_size += 8; /* snap_seq */
	msg_size += 4 + 8 * (req->r_snapc ? req->r_snapc->num_snaps : 0);
	msg_size += 4 + 8; /* retry_attempt, features */

	if (req->r_mempool)
		msg = ceph_msgpool_get(&osdc->msgpool_op, 0);
	else
		msg = ceph_msg_new(CEPH_MSG_OSD_OP, msg_size, gfp, true);
	if (!msg)
		return -ENOMEM;

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

	/* create reply message */
	msg_size = OSD_OPREPLY_FRONT_LEN;
	msg_size += req->r_base_oid.name_len;
	msg_size += req->r_num_ops * sizeof(struct ceph_osd_op);

	if (req->r_mempool)
		msg = ceph_msgpool_get(&osdc->msgpool_op_reply, 0);
	else
		msg = ceph_msg_new(CEPH_MSG_OSD_OPREPLY, msg_size, gfp, true);
	if (!msg)
		return -ENOMEM;

	req->r_reply = msg;

	return 0;
}
EXPORT_SYMBOL(ceph_osdc_alloc_messages);

static bool osd_req_opcode_valid(u16 opcode)
{
	switch (opcode) {
#define GENERATE_CASE(op, opcode, str)	case CEPH_OSD_OP_##op: return true;
__CEPH_FORALL_OSD_OPS(GENERATE_CASE)
#undef GENERATE_CASE
	default:
		return false;
	}
}

/*
 * This is an osd op init function for opcodes that have no data or
 * other information associated with them.  It also serves as a
 * common init routine for all the other init functions, below.
 */
static struct ceph_osd_req_op *
_osd_req_op_init(struct ceph_osd_request *osd_req, unsigned int which,
		 u16 opcode, u32 flags)
{
	struct ceph_osd_req_op *op;

	BUG_ON(which >= osd_req->r_num_ops);
	BUG_ON(!osd_req_opcode_valid(opcode));

	op = &osd_req->r_ops[which];
	memset(op, 0, sizeof (*op));
	op->op = opcode;
	op->flags = flags;

	return op;
}

void osd_req_op_init(struct ceph_osd_request *osd_req,
		     unsigned int which, u16 opcode, u32 flags)
{
	(void)_osd_req_op_init(osd_req, which, opcode, flags);
}
EXPORT_SYMBOL(osd_req_op_init);

void osd_req_op_extent_init(struct ceph_osd_request *osd_req,
				unsigned int which, u16 opcode,
				u64 offset, u64 length,
				u64 truncate_size, u32 truncate_seq)
{
	struct ceph_osd_req_op *op = _osd_req_op_init(osd_req, which,
						      opcode, 0);
	size_t payload_len = 0;

	BUG_ON(opcode != CEPH_OSD_OP_READ && opcode != CEPH_OSD_OP_WRITE &&
	       opcode != CEPH_OSD_OP_WRITEFULL && opcode != CEPH_OSD_OP_ZERO &&
	       opcode != CEPH_OSD_OP_TRUNCATE);

	op->extent.offset = offset;
	op->extent.length = length;
	op->extent.truncate_size = truncate_size;
	op->extent.truncate_seq = truncate_seq;
	if (opcode == CEPH_OSD_OP_WRITE || opcode == CEPH_OSD_OP_WRITEFULL)
		payload_len += length;

	op->indata_len = payload_len;
}
EXPORT_SYMBOL(osd_req_op_extent_init);

void osd_req_op_extent_update(struct ceph_osd_request *osd_req,
				unsigned int which, u64 length)
{
	struct ceph_osd_req_op *op;
	u64 previous;

	BUG_ON(which >= osd_req->r_num_ops);
	op = &osd_req->r_ops[which];
	previous = op->extent.length;

	if (length == previous)
		return;		/* Nothing to do */
	BUG_ON(length > previous);

	op->extent.length = length;
	if (op->op == CEPH_OSD_OP_WRITE || op->op == CEPH_OSD_OP_WRITEFULL)
		op->indata_len -= previous - length;
}
EXPORT_SYMBOL(osd_req_op_extent_update);

void osd_req_op_extent_dup_last(struct ceph_osd_request *osd_req,
				unsigned int which, u64 offset_inc)
{
	struct ceph_osd_req_op *op, *prev_op;

	BUG_ON(which + 1 >= osd_req->r_num_ops);

	prev_op = &osd_req->r_ops[which];
	op = _osd_req_op_init(osd_req, which + 1, prev_op->op, prev_op->flags);
	/* dup previous one */
	op->indata_len = prev_op->indata_len;
	op->outdata_len = prev_op->outdata_len;
	op->extent = prev_op->extent;
	/* adjust offset */
	op->extent.offset += offset_inc;
	op->extent.length -= offset_inc;

	if (op->op == CEPH_OSD_OP_WRITE || op->op == CEPH_OSD_OP_WRITEFULL)
		op->indata_len -= offset_inc;
}
EXPORT_SYMBOL(osd_req_op_extent_dup_last);

int osd_req_op_cls_init(struct ceph_osd_request *osd_req, unsigned int which,
			u16 opcode, const char *class, const char *method)
{
	struct ceph_osd_req_op *op = _osd_req_op_init(osd_req, which,
						      opcode, 0);
	struct ceph_pagelist *pagelist;
	size_t payload_len = 0;
	size_t size;

	BUG_ON(opcode != CEPH_OSD_OP_CALL);

	pagelist = kmalloc(sizeof (*pagelist), GFP_NOFS);
	if (!pagelist)
		return -ENOMEM;

	ceph_pagelist_init(pagelist);

	op->cls.class_name = class;
	size = strlen(class);
	BUG_ON(size > (size_t) U8_MAX);
	op->cls.class_len = size;
	ceph_pagelist_append(pagelist, class, size);
	payload_len += size;

	op->cls.method_name = method;
	size = strlen(method);
	BUG_ON(size > (size_t) U8_MAX);
	op->cls.method_len = size;
	ceph_pagelist_append(pagelist, method, size);
	payload_len += size;

	osd_req_op_cls_request_info_pagelist(osd_req, which, pagelist);

	op->indata_len = payload_len;
	return 0;
}
EXPORT_SYMBOL(osd_req_op_cls_init);

int osd_req_op_xattr_init(struct ceph_osd_request *osd_req, unsigned int which,
			  u16 opcode, const char *name, const void *value,
			  size_t size, u8 cmp_op, u8 cmp_mode)
{
	struct ceph_osd_req_op *op = _osd_req_op_init(osd_req, which,
						      opcode, 0);
	struct ceph_pagelist *pagelist;
	size_t payload_len;

	BUG_ON(opcode != CEPH_OSD_OP_SETXATTR && opcode != CEPH_OSD_OP_CMPXATTR);

	pagelist = kmalloc(sizeof(*pagelist), GFP_NOFS);
	if (!pagelist)
		return -ENOMEM;

	ceph_pagelist_init(pagelist);

	payload_len = strlen(name);
	op->xattr.name_len = payload_len;
	ceph_pagelist_append(pagelist, name, payload_len);

	op->xattr.value_len = size;
	ceph_pagelist_append(pagelist, value, size);
	payload_len += size;

	op->xattr.cmp_op = cmp_op;
	op->xattr.cmp_mode = cmp_mode;

	ceph_osd_data_pagelist_init(&op->xattr.osd_data, pagelist);
	op->indata_len = payload_len;
	return 0;
}
EXPORT_SYMBOL(osd_req_op_xattr_init);

/*
 * @watch_opcode: CEPH_OSD_WATCH_OP_*
 */
static void osd_req_op_watch_init(struct ceph_osd_request *req, int which,
				  u64 cookie, u8 watch_opcode)
{
	struct ceph_osd_req_op *op;

	op = _osd_req_op_init(req, which, CEPH_OSD_OP_WATCH, 0);
	op->watch.cookie = cookie;
	op->watch.op = watch_opcode;
	op->watch.gen = 0;
}

void osd_req_op_alloc_hint_init(struct ceph_osd_request *osd_req,
				unsigned int which,
				u64 expected_object_size,
				u64 expected_write_size)
{
	struct ceph_osd_req_op *op = _osd_req_op_init(osd_req, which,
						      CEPH_OSD_OP_SETALLOCHINT,
						      0);

	op->alloc_hint.expected_object_size = expected_object_size;
	op->alloc_hint.expected_write_size = expected_write_size;

	/*
	 * CEPH_OSD_OP_SETALLOCHINT op is advisory and therefore deemed
	 * not worth a feature bit.  Set FAILOK per-op flag to make
	 * sure older osds don't trip over an unsupported opcode.
	 */
	op->flags |= CEPH_OSD_OP_FLAG_FAILOK;
}
EXPORT_SYMBOL(osd_req_op_alloc_hint_init);

static void ceph_osdc_msg_data_add(struct ceph_msg *msg,
				struct ceph_osd_data *osd_data)
{
	u64 length = ceph_osd_data_length(osd_data);

	if (osd_data->type == CEPH_OSD_DATA_TYPE_PAGES) {
		BUG_ON(length > (u64) SIZE_MAX);
		if (length)
			ceph_msg_data_add_pages(msg, osd_data->pages,
					length, osd_data->alignment);
	} else if (osd_data->type == CEPH_OSD_DATA_TYPE_PAGELIST) {
		BUG_ON(!length);
		ceph_msg_data_add_pagelist(msg, osd_data->pagelist);
#ifdef CONFIG_BLOCK
	} else if (osd_data->type == CEPH_OSD_DATA_TYPE_BIO) {
		ceph_msg_data_add_bio(msg, &osd_data->bio_pos, length);
#endif
	} else if (osd_data->type == CEPH_OSD_DATA_TYPE_BVECS) {
		ceph_msg_data_add_bvecs(msg, &osd_data->bvec_pos);
	} else {
		BUG_ON(osd_data->type != CEPH_OSD_DATA_TYPE_NONE);
	}
}

static u32 osd_req_encode_op(struct ceph_osd_op *dst,
			     const struct ceph_osd_req_op *src)
{
	if (WARN_ON(!osd_req_opcode_valid(src->op))) {
		pr_err("unrecognized osd opcode %d\n", src->op);

		return 0;
	}

	switch (src->op) {
	case CEPH_OSD_OP_STAT:
		break;
	case CEPH_OSD_OP_READ:
	case CEPH_OSD_OP_WRITE:
	case CEPH_OSD_OP_WRITEFULL:
	case CEPH_OSD_OP_ZERO:
	case CEPH_OSD_OP_TRUNCATE:
		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_CALL:
		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);
		break;
	case CEPH_OSD_OP_WATCH:
		dst->watch.cookie = cpu_to_le64(src->watch.cookie);
		dst->watch.ver = cpu_to_le64(0);
		dst->watch.op = src->watch.op;
		dst->watch.gen = cpu_to_le32(src->watch.gen);
		break;
	case CEPH_OSD_OP_NOTIFY_ACK:
		break;
	case CEPH_OSD_OP_NOTIFY:
		dst->notify.cookie = cpu_to_le64(src->notify.cookie);
		break;
	case CEPH_OSD_OP_LIST_WATCHERS:
		break;
	case CEPH_OSD_OP_SETALLOCHINT:
		dst->alloc_hint.expected_object_size =
		    cpu_to_le64(src->alloc_hint.expected_object_size);
		dst->alloc_hint.expected_write_size =
		    cpu_to_le64(src->alloc_hint.expected_write_size);
		break;
	case CEPH_OSD_OP_SETXATTR:
	case CEPH_OSD_OP_CMPXATTR:
		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;
		break;
	case CEPH_OSD_OP_CREATE:
	case CEPH_OSD_OP_DELETE:
		break;
	default:
		pr_err("unsupported osd opcode %s\n",
			ceph_osd_op_name(src->op));
		WARN_ON(1);

		return 0;
	}

	dst->op = cpu_to_le16(src->op);
	dst->flags = cpu_to_le32(src->flags);
	dst->payload_len = cpu_to_le32(src->indata_len);

	return src->indata_len;
}

/*
 * 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.)
 */
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,
					       unsigned int which, int num_ops,
					       int opcode, int flags,
					       struct ceph_snap_context *snapc,
					       u32 truncate_seq,
					       u64 truncate_size,
					       bool use_mempool)
{
	struct ceph_osd_request *req;
	u64 objnum = 0;
	u64 objoff = 0;
	u64 objlen = 0;
	int r;

	BUG_ON(opcode != CEPH_OSD_OP_READ && opcode != CEPH_OSD_OP_WRITE &&
	       opcode != CEPH_OSD_OP_ZERO && opcode != CEPH_OSD_OP_TRUNCATE &&
	       opcode != CEPH_OSD_OP_CREATE && opcode != CEPH_OSD_OP_DELETE);

	req = ceph_osdc_alloc_request(osdc, snapc, num_ops, use_mempool,
					GFP_NOFS);
	if (!req) {
		r = -ENOMEM;
		goto fail;
	}

	/* calculate max write size */
	r = calc_layout(layout, off, plen, &objnum, &objoff, &objlen);
	if (r)
		goto fail;

	if (opcode == CEPH_OSD_OP_CREATE || opcode == CEPH_OSD_OP_DELETE) {
		osd_req_op_init(req, which, opcode, 0);
	} else {
		u32 object_size = layout->object_size;
		u32 object_base = off - objoff;
		if (!(truncate_seq == 1 && truncate_size == -1ULL)) {
			if (truncate_size <= object_base) {
				truncate_size = 0;
			} else {
				truncate_size -= object_base;
				if (truncate_size > object_size)
					truncate_size = object_size;
			}
		}
		osd_req_op_extent_init(req, which, opcode, objoff, objlen,
				       truncate_size, truncate_seq);
	}

	req->r_flags = flags;
	req->r_base_oloc.pool = layout->pool_id;
	req->r_base_oloc.pool_ns = ceph_try_get_string(layout->pool_ns);
	ceph_oid_printf(&req->r_base_oid, "%llx.%08llx", vino.ino, objnum);

	req->r_snapid = vino.snap;
	if (flags & CEPH_OSD_FLAG_WRITE)
		req->r_data_offset = off;

	r = ceph_osdc_alloc_messages(req, GFP_NOFS);
	if (r)
		goto fail;

	return req;

fail:
	ceph_osdc_put_request(req);
	return ERR_PTR(r);
}
EXPORT_SYMBOL(ceph_osdc_new_request);

/*
 * We keep osd requests in an rbtree, sorted by ->r_tid.
 */
DEFINE_RB_FUNCS(request, struct ceph_osd_request, r_tid, r_node)
DEFINE_RB_FUNCS(request_mc, struct ceph_osd_request, r_tid, r_mc_node)

/*
 * Call @fn on each OSD request as long as @fn returns 0.
 */
static void for_each_request(struct ceph_osd_client *osdc,
			int (*fn)(struct ceph_osd_request *req, void *arg),
			void *arg)
{
	struct rb_node *n, *p;

	for (n = rb_first(&osdc->osds); n; n = rb_next(n)) {
		struct ceph_osd *osd = rb_entry(n, struct ceph_osd, o_node);

		for (p = rb_first(&osd->o_requests); p; ) {
			struct ceph_osd_request *req =
			    rb_entry(p, struct ceph_osd_request, r_node);

			p = rb_next(p);
			if (fn(req, arg))
				return;
		}
	}

	for (p = rb_first(&osdc->homeless_osd.o_requests); p; ) {
		struct ceph_osd_request *req =
		    rb_entry(p, struct ceph_osd_request, r_node);

		p = rb_next(p);
		if (fn(req, arg))
			return;
	}
}

static bool osd_homeless(struct ceph_osd *osd)
{
	return osd->o_osd == CEPH_HOMELESS_OSD;
}

static bool osd_registered(struct ceph_osd *osd)
{
	verify_osdc_locked(osd->o_osdc);

	return !RB_EMPTY_NODE(&osd->o_node);
}

/*
 * Assumes @osd is zero-initialized.
 */
static void osd_init(struct ceph_osd *osd)
{
	refcount_set(&osd->o_ref, 1);
	RB_CLEAR_NODE(&osd->o_node);
	osd->o_requests = RB_ROOT;
	osd->o_linger_requests = RB_ROOT;
	osd->o_backoff_mappings = RB_ROOT;
	osd->o_backoffs_by_id = RB_ROOT;
	INIT_LIST_HEAD(&osd->o_osd_lru);
	INIT_LIST_HEAD(&osd->o_keepalive_item);
	osd->o_incarnation = 1;
	mutex_init(&osd->lock);
}

static void osd_cleanup(struct ceph_osd *osd)
{
	WARN_ON(!RB_EMPTY_NODE(&osd->o_node));
	WARN_ON(!RB_EMPTY_ROOT(&osd->o_requests));
	WARN_ON(!RB_EMPTY_ROOT(&osd->o_linger_requests));
	WARN_ON(!RB_EMPTY_ROOT(&osd->o_backoff_mappings));
	WARN_ON(!RB_EMPTY_ROOT(&osd->o_backoffs_by_id));
	WARN_ON(!list_empty(&osd->o_osd_lru));
	WARN_ON(!list_empty(&osd->o_keepalive_item));

	if (osd->o_auth.authorizer) {
		WARN_ON(osd_homeless(osd));
		ceph_auth_destroy_authorizer(osd->o_auth.authorizer);
	}
}

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

	WARN_ON(onum == CEPH_HOMELESS_OSD);

	osd = kzalloc(sizeof(*osd), GFP_NOIO | __GFP_NOFAIL);
	osd_init(osd);
	osd->o_osdc = osdc;
	osd->o_osd = onum;

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

	return osd;
}

static struct ceph_osd *get_osd(struct ceph_osd *osd)
{
	if (refcount_inc_not_zero(&osd->o_ref)) {
		dout("get_osd %p %d -> %d\n", osd, refcount_read(&osd->o_ref)-1,
		     refcount_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, refcount_read(&osd->o_ref),
	     refcount_read(&osd->o_ref) - 1);
	if (refcount_dec_and_test(&osd->o_ref)) {
		osd_cleanup(osd);
		kfree(osd);
	}
}

DEFINE_RB_FUNCS(osd, struct ceph_osd, o_osd, o_node)

static void __move_osd_to_lru(struct ceph_osd *osd)
{
	struct ceph_osd_client *osdc = osd->o_osdc;

	dout("%s osd %p osd%d\n", __func__, osd, osd->o_osd);
	BUG_ON(!list_empty(&osd->o_osd_lru));

	spin_lock(&osdc->osd_lru_lock);
	list_add_tail(&osd->o_osd_lru, &osdc->osd_lru);
	spin_unlock(&osdc->osd_lru_lock);

	osd->lru_ttl = jiffies + osdc->client->options->osd_idle_ttl;
}

static void maybe_move_osd_to_lru(struct ceph_osd *osd)
{
	if (RB_EMPTY_ROOT(&osd->o_requests) &&
	    RB_EMPTY_ROOT(&osd->o_linger_requests))
		__move_osd_to_lru(osd);
}

static void __remove_osd_from_lru(struct ceph_osd *osd)
{
	struct ceph_osd_client *osdc = osd->o_osdc;

	dout("%s osd %p osd%d\n", __func__, osd, osd->o_osd);

	spin_lock(&osdc->osd_lru_lock);
	if (!list_empty(&osd->o_osd_lru))
		list_del_init(&osd->o_osd_lru);
	spin_unlock(&osdc->osd_lru_lock);
}

/*
 * Close the connection and assign any leftover requests to the
 * homeless session.
 */
static void close_osd(struct ceph_osd *osd)
{
	struct ceph_osd_client *osdc = osd->o_osdc;
	struct rb_node *n;

	verify_osdc_wrlocked(osdc);
	dout("%s osd %p osd%d\n", __func__, osd, osd->o_osd);

	ceph_con_close(&osd->o_con);

	for (n = rb_first(&osd->o_requests); n; ) {
		struct ceph_osd_request *req =
		    rb_entry(n, struct ceph_osd_request, r_node);

		n = rb_next(n); /* unlink_request() */

		dout(" reassigning req %p tid %llu\n", req, req->r_tid);
		unlink_request(osd, req);
		link_request(&osdc->homeless_osd, req);
	}
	for (n = rb_first(&osd->o_linger_requests); n; ) {
		struct ceph_osd_linger_request *lreq =
		    rb_entry(n, struct ceph_osd_linger_request, node);

		n = rb_next(n); /* unlink_linger() */

		dout(" reassigning lreq %p linger_id %llu\n", lreq,
		     lreq->linger_id);
		unlink_linger(osd, lreq);
		link_linger(&osdc->homeless_osd, lreq);
	}
	clear_backoffs(osd);

	__remove_osd_from_lru(osd);
	erase_osd(&osdc->osds, osd);
	put_osd(osd);
}

/*
 * reset osd connect
 */
static int reopen_osd(struct ceph_osd *osd)
{
	struct ceph_entity_addr *peer_addr;

	dout("%s osd %p osd%d\n", __func__, osd, osd->o_osd);

	if (RB_EMPTY_ROOT(&osd->o_requests) &&
	    RB_EMPTY_ROOT(&osd->o_linger_requests)) {
		close_osd(osd);
		return -ENODEV;
	}

	peer_addr = &osd->o_osdc->osdmap->osd_addr[osd->o_osd];
	if (!memcmp(peer_addr, &osd->o_con.peer_addr, sizeof (*peer_addr)) &&
			!ceph_con_opened(&osd->o_con)) {
		struct rb_node *n;

		dout("osd addr hasn't changed and connection never opened, "
		     "letting msgr retry\n");
		/* touch each r_stamp for handle_timeout()'s benfit */
		for (n = rb_first(&osd->o_requests); n; n = rb_next(n)) {
			struct ceph_osd_request *req =
			    rb_entry(n, struct ceph_osd_request, r_node);
			req->r_stamp = jiffies;
		}

		return -EAGAIN;
	}

	ceph_con_close(&osd->o_con);
	ceph_con_open(&osd->o_con, CEPH_ENTITY_TYPE_OSD, osd->o_osd, peer_addr);
	osd->o_incarnation++;

	return 0;
}

static struct ceph_osd *lookup_create_osd(struct ceph_osd_client *osdc, int o,
					  bool wrlocked)
{
	struct ceph_osd *osd;

	if (wrlocked)
		verify_osdc_wrlocked(osdc);
	else
		verify_osdc_locked(osdc);

	if (o != CEPH_HOMELESS_OSD)
		osd = lookup_osd(&osdc->osds, o);
	else
		osd = &osdc->homeless_osd;
	if (!osd) {
		if (!wrlocked)
			return ERR_PTR(-EAGAIN);

		osd = create_osd(osdc, o);
		insert_osd(&osdc->osds, osd);
		ceph_con_open(&osd->o_con, CEPH_ENTITY_TYPE_OSD, osd->o_osd,
			      &osdc->osdmap->osd_addr[osd->o_osd]);
	}

	dout("%s osdc %p osd%d -> osd %p\n", __func__, osdc, o, osd);
	return osd;
}

/*
 * Create request <-> OSD session relation.
 *
 * @req has to be assigned a tid, @osd may be homeless.
 */
static void link_request(struct ceph_osd *osd, struct ceph_osd_request *req)
{
	verify_osd_locked(osd);
	WARN_ON(!req->r_tid || req->r_osd);
	dout("%s osd %p osd%d req %p tid %llu\n", __func__, osd, osd->o_osd,
	     req, req->r_tid);

	if (!osd_homeless(osd))
		__remove_osd_from_lru(osd);
	else
		atomic_inc(&osd->o_osdc->num_homeless);

	get_osd(osd);
	insert_request(&osd->o_requests, req);
	req->r_osd = osd;
}

static void unlink_request(struct ceph_osd *osd, struct ceph_osd_request *req)
{
	verify_osd_locked(osd);
	WARN_ON(req->r_osd != osd);
	dout("%s osd %p osd%d req %p tid %llu\n", __func__, osd, osd->o_osd,
	     req, req->r_tid);

	req->r_osd = NULL;
	erase_request(&osd->o_requests, req);
	put_osd(osd);

	if (!osd_homeless(osd))
		maybe_move_osd_to_lru(osd);
	else
		atomic_dec(&osd->o_osdc->num_homeless);
}

static bool __pool_full(struct ceph_pg_pool_info *pi)
{
	return pi->flags & CEPH_POOL_FLAG_FULL;
}

static bool have_pool_full(struct ceph_osd_client *osdc)
{
	struct rb_node *n;

	for (n = rb_first(&osdc->osdmap->pg_pools); n; n = rb_next(n)) {
		struct ceph_pg_pool_info *pi =
		    rb_entry(n, struct ceph_pg_pool_info, node);

		if (__pool_full(pi))
			return true;
	}

	return false;
}

static bool pool_full(struct ceph_osd_client *osdc, s64 pool_id)
{
	struct ceph_pg_pool_info *pi;

	pi = ceph_pg_pool_by_id(osdc->osdmap, pool_id);
	if (!pi)
		return false;

	return __pool_full(pi);
}

/*
 * Returns whether a request should be blocked from being sent
 * based on the current osdmap and osd_client settings.
 */
static bool target_should_be_paused(struct ceph_osd_client *osdc,
				    const struct ceph_osd_request_target *t,
				    struct ceph_pg_pool_info *pi)
{
	bool pauserd = ceph_osdmap_flag(osdc, CEPH_OSDMAP_PAUSERD);
	bool pausewr = ceph_osdmap_flag(osdc, CEPH_OSDMAP_PAUSEWR) ||
		       ceph_osdmap_flag(osdc, CEPH_OSDMAP_FULL) ||
		       __pool_full(pi);

	WARN_ON(pi->id != t->target_oloc.pool);
	return ((t->flags & CEPH_OSD_FLAG_READ) && pauserd) ||
	       ((t->flags & CEPH_OSD_FLAG_WRITE) && pausewr) ||
	       (osdc->osdmap->epoch < osdc->epoch_barrier);
}

enum calc_target_result {
	CALC_TARGET_NO_ACTION = 0,
	CALC_TARGET_NEED_RESEND,
	CALC_TARGET_POOL_DNE,
};

static enum calc_target_result calc_target(struct ceph_osd_client *osdc,
					   struct ceph_osd_request_target *t,
					   struct ceph_connection *con,
					   bool any_change)
{
	struct ceph_pg_pool_info *pi;
	struct ceph_pg pgid, last_pgid;
	struct ceph_osds up, acting;
	bool force_resend = false;
	bool unpaused = false;
	bool legacy_change = false;
	bool split = false;
	bool sort_bitwise = ceph_osdmap_flag(osdc, CEPH_OSDMAP_SORTBITWISE);
	bool recovery_deletes = ceph_osdmap_flag(osdc,
						 CEPH_OSDMAP_RECOVERY_DELETES);
	enum calc_target_result ct_res;

	t->epoch = osdc->osdmap->epoch;
	pi = ceph_pg_pool_by_id(osdc->osdmap, t->base_oloc.pool);
	if (!pi) {
		t->osd = CEPH_HOMELESS_OSD;
		ct_res = CALC_TARGET_POOL_DNE;
		goto out;
	}

	if (osdc->osdmap->epoch == pi->last_force_request_resend) {
		if (t->last_force_resend < pi->last_force_request_resend) {
			t->last_force_resend = pi->last_force_request_resend;
			force_resend = true;
		} else if (t->last_force_resend == 0) {
			force_resend = true;
		}
	}

	/* apply tiering */
	ceph_oid_copy(&t->target_oid, &t->base_oid);
	ceph_oloc_copy(&t->target_oloc, &t->base_oloc);
	if ((t->flags & CEPH_OSD_FLAG_IGNORE_OVERLAY) == 0) {
		if (t->flags & CEPH_OSD_FLAG_READ && pi->read_tier >= 0)
			t->target_oloc.pool = pi->read_tier;
		if (t->flags & CEPH_OSD_FLAG_WRITE && pi->write_tier >= 0)
			t->target_oloc.pool = pi->write_tier;

		pi = ceph_pg_pool_by_id(osdc->osdmap, t->target_oloc.pool);
		if (!pi) {
			t->osd = CEPH_HOMELESS_OSD;
			ct_res = CALC_TARGET_POOL_DNE;
			goto out;
		}
	}

	__ceph_object_locator_to_pg(pi, &t->target_oid, &t->target_oloc, &pgid);
	last_pgid.pool = pgid.pool;
	last_pgid.seed = ceph_stable_mod(pgid.seed, t->pg_num, t->pg_num_mask);

	ceph_pg_to_up_acting_osds(osdc->osdmap, pi, &pgid, &up, &acting);
	if (any_change &&
	    ceph_is_new_interval(&t->acting,
				 &acting,
				 &t->up,
				 &up,
				 t->size,
				 pi->size,
				 t->min_size,
				 pi->min_size,
				 t->pg_num,
				 pi->pg_num,
				 t->sort_bitwise,
				 sort_bitwise,
				 t->recovery_deletes,
				 recovery_deletes,
				 &last_pgid))
		force_resend = true;

	if (t->paused && !target_should_be_paused(osdc, t, pi)) {
		t->paused = false;
		unpaused = true;
	}
	legacy_change = ceph_pg_compare(&t->pgid, &pgid) ||
			ceph_osds_changed(&t->acting, &acting, any_change);
	if (t->pg_num)
		split = ceph_pg_is_split(&last_pgid, t->pg_num, pi->pg_num);

	if (legacy_change || force_resend || split) {
		t->pgid = pgid; /* struct */
		ceph_pg_to_primary_shard(osdc->osdmap, pi, &pgid, &t->spgid);
		ceph_osds_copy(&t->acting, &acting);
		ceph_osds_copy(&t->up, &up);
		t->size = pi->size;
		t->min_size = pi->min_size;
		t->pg_num = pi->pg_num;
		t->pg_num_mask = pi->pg_num_mask;
		t->sort_bitwise = sort_bitwise;
		t->recovery_deletes = recovery_deletes;

		t->osd = acting.primary;
	}

	if (unpaused || legacy_change || force_resend || split)
		ct_res = CALC_TARGET_NEED_RESEND;
	else
		ct_res = CALC_TARGET_NO_ACTION;

out:
	dout("%s t %p -> %d%d%d%d ct_res %d osd%d\n", __func__, t, unpaused,
	     legacy_change, force_resend, split, ct_res, t->osd);
	return ct_res;
}

static struct ceph_spg_mapping *alloc_spg_mapping(void)
{
	struct ceph_spg_mapping *spg;

	spg = kmalloc(sizeof(*spg), GFP_NOIO);
	if (!spg)
		return NULL;

	RB_CLEAR_NODE(&spg->node);
	spg->backoffs = RB_ROOT;
	return spg;
}

static void free_spg_mapping(struct ceph_spg_mapping *spg)
{
	WARN_ON(!RB_EMPTY_NODE(&spg->node));
	WARN_ON(!RB_EMPTY_ROOT(&spg->backoffs));

	kfree(spg);
}

/*
 * rbtree of ceph_spg_mapping for handling map<spg_t, ...>, similar to
 * ceph_pg_mapping.  Used to track OSD backoffs -- a backoff [range] is
 * defined only within a specific spgid; it does not pass anything to
 * children on split, or to another primary.
 */
DEFINE_RB_FUNCS2(spg_mapping, struct ceph_spg_mapping, spgid, ceph_spg_compare,
		 RB_BYPTR, const struct ceph_spg *, node)

static u64 hoid_get_bitwise_key(const struct ceph_hobject_id *hoid)
{
	return hoid->is_max ? 0x100000000ull : hoid->hash_reverse_bits;
}

static void hoid_get_effective_key(const struct ceph_hobject_id *hoid,
				   void **pkey, size_t *pkey_len)
{
	if (hoid->key_len) {
		*pkey = hoid->key;
		*pkey_len = hoid->key_len;
	} else {
		*pkey = hoid->oid;
		*pkey_len = hoid->oid_len;
	}
}

static int compare_names(const void *name1, size_t name1_len,
			 const void *name2, size_t name2_len)
{
	int ret;

	ret = memcmp(name1, name2, min(name1_len, name2_len));
	if (!ret) {
		if (name1_len < name2_len)
			ret = -1;
		else if (name1_len > name2_len)
			ret = 1;
	}
	return ret;
}

static int hoid_compare(const struct ceph_hobject_id *lhs,
			const struct ceph_hobject_id *rhs)
{
	void *effective_key1, *effective_key2;
	size_t effective_key1_len, effective_key2_len;
	int ret;

	if (lhs->is_max < rhs->is_max)
		return -1;
	if (lhs->is_max > rhs->is_max)
		return 1;

	if (lhs->pool < rhs->pool)
		return -1;
	if (lhs->pool > rhs->pool)
		return 1;

	if (hoid_get_bitwise_key(lhs) < hoid_get_bitwise_key(rhs))
		return -1;
	if (hoid_get_bitwise_key(lhs) > hoid_get_bitwise_key(rhs))
		return 1;

	ret = compare_names(lhs->nspace, lhs->nspace_len,
			    rhs->nspace, rhs->nspace_len);
	if (ret)
		return ret;

	hoid_get_effective_key(lhs, &effective_key1, &effective_key1_len);
	hoid_get_effective_key(rhs, &effective_key2, &effective_key2_len);
	ret = compare_names(effective_key1, effective_key1_len,
			    effective_key2, effective_key2_len);
	if (ret)
		return ret;

	ret = compare_names(lhs->oid, lhs->oid_len, rhs->oid, rhs->oid_len);
	if (ret)
		return ret;

	if (lhs->snapid < rhs->snapid)
		return -1;
	if (lhs->snapid > rhs->snapid)
		return 1;

	return 0;
}

/*
 * For decoding ->begin and ->end of MOSDBackoff only -- no MIN/MAX
 * compat stuff here.
 *
 * Assumes @hoid is zero-initialized.
 */
static int decode_hoid(void **p, void *end, struct ceph_hobject_id *hoid)
{
	u8 struct_v;
	u32 struct_len;
	int ret;

	ret = ceph_start_decoding(p, end, 4, "hobject_t", &struct_v,
				  &struct_len);
	if (ret)
		return ret;

	if (struct_v < 4) {
		pr_err("got struct_v %d < 4 of hobject_t\n", struct_v);
		goto e_inval;
	}

	hoid->key = ceph_extract_encoded_string(p, end, &hoid->key_len,
						GFP_NOIO);
	if (IS_ERR(hoid->key)) {
		ret = PTR_ERR(hoid->key);
		hoid->key = NULL;
		return ret;
	}

	hoid->oid = ceph_extract_encoded_string(p, end, &hoid->oid_len,
						GFP_NOIO);
	if (IS_ERR(hoid->oid)) {
		ret = PTR_ERR(hoid->oid);
		hoid->oid = NULL;
		return ret;
	}

	ceph_decode_64_safe(p, end, hoid->snapid, e_inval);
	ceph_decode_32_safe(p, end, hoid->hash, e_inval);
	ceph_decode_8_safe(p, end, hoid->is_max, e_inval);

	hoid->nspace = ceph_extract_encoded_string(p, end, &hoid->nspace_len,
						   GFP_NOIO);
	if (IS_ERR(hoid->nspace)) {
		ret = PTR_ERR(hoid->nspace);
		hoid->nspace = NULL;
		return ret;
	}

	ceph_decode_64_safe(p, end, hoid->pool, e_inval);

	ceph_hoid_build_hash_cache(hoid);
	return 0;

e_inval:
	return -EINVAL;
}

static int hoid_encoding_size(const struct ceph_hobject_id *hoid)
{
	return 8 + 4 + 1 + 8 + /* snapid, hash, is_max, pool */
	       4 + hoid->key_len + 4 + hoid->oid_len + 4 + hoid->nspace_len;
}

static void encode_hoid(void **p, void *end, const struct ceph_hobject_id *hoid)
{
	ceph_start_encoding(p, 4, 3, hoid_encoding_size(hoid));
	ceph_encode_string(p, end, hoid->key, hoid->key_len);
	ceph_encode_string(p, end, hoid->oid, hoid->oid_len);
	ceph_encode_64(p, hoid->snapid);
	ceph_encode_32(p, hoid->hash);
	ceph_encode_8(p, hoid->is_max);
	ceph_encode_string(p, end, hoid->nspace, hoid->nspace_len);
	ceph_encode_64(p, hoid->pool);
}

static void free_hoid(struct ceph_hobject_id *hoid)
{
	if (hoid) {
		kfree(hoid->key);
		kfree(hoid->oid);
		kfree(hoid->nspace);
		kfree(hoid);
	}
}

static struct ceph_osd_backoff *alloc_backoff(void)
{
	struct ceph_osd_backoff *backoff;

	backoff = kzalloc(sizeof(*backoff), GFP_NOIO);
	if (!backoff)
		return NULL;

	RB_CLEAR_NODE(&backoff->spg_node);
	RB_CLEAR_NODE(&backoff->id_node);
	return backoff;
}

static void free_backoff(struct ceph_osd_backoff *backoff)
{
	WARN_ON(!RB_EMPTY_NODE(&backoff->spg_node));
	WARN_ON(!RB_EMPTY_NODE(&backoff->id_node));

	free_hoid(backoff->begin);
	free_hoid(backoff->end);
	kfree(backoff);
}

/*
 * Within a specific spgid, backoffs are managed by ->begin hoid.
 */
DEFINE_RB_INSDEL_FUNCS2(backoff, struct ceph_osd_backoff, begin, hoid_compare,
			RB_BYVAL, spg_node);

static struct ceph_osd_backoff *lookup_containing_backoff(struct rb_root *root,
					    const struct ceph_hobject_id *hoid)
{
	struct rb_node *n = root->rb_node;

	while (n) {
		struct ceph_osd_backoff *cur =
		    rb_entry(n, struct ceph_osd_backoff, spg_node);
		int cmp;

		cmp = hoid_compare(hoid, cur->begin);
		if (cmp < 0) {
			n = n->rb_left;
		} else if (cmp > 0) {
			if (hoid_compare(hoid, cur->end) < 0)
				return cur;

			n = n->rb_right;
		} else {
			return cur;
		}
	}

	return NULL;
}

/*
 * Each backoff has a unique id within its OSD session.
 */
DEFINE_RB_FUNCS(backoff_by_id, struct ceph_osd_backoff, id, id_node)

static void clear_backoffs(struct ceph_osd *osd)
{
	while (!RB_EMPTY_ROOT(&osd->o_backoff_mappings)) {
		struct ceph_spg_mapping *spg =
		    rb_entry(rb_first(&osd->o_backoff_mappings),
			     struct ceph_spg_mapping, node);

		while (!RB_EMPTY_ROOT(&spg->backoffs)) {
			struct ceph_osd_backoff *backoff =
			    rb_entry(rb_first(&spg->backoffs),
				     struct ceph_osd_backoff, spg_node);

			erase_backoff(&spg->backoffs, backoff);
			erase_backoff_by_id(&osd->o_backoffs_by_id, backoff);
			free_backoff(backoff);
		}
		erase_spg_mapping(&osd->o_backoff_mappings, spg);
		free_spg_mapping(spg);
	}
}

/*
 * Set up a temporary, non-owning view into @t.
 */
static void hoid_fill_from_target(struct ceph_hobject_id *hoid,
				  const struct ceph_osd_request_target *t)
{
	hoid->key = NULL;
	hoid->key_len = 0;
	hoid->oid = t->target_oid.name;
	hoid->oid_len = t->target_oid.name_len;
	hoid->snapid = CEPH_NOSNAP;
	hoid->hash = t->pgid.seed;
	hoid->is_max = false;
	if (t->target_oloc.pool_ns) {
		hoid->nspace = t->target_oloc.pool_ns->str;
		hoid->nspace_len = t->target_oloc.pool_ns->len;
	} else {
		hoid->nspace = NULL;
		hoid->nspace_len = 0;
	}
	hoid->pool = t->target_oloc.pool;
	ceph_hoid_build_hash_cache(hoid);
}

static bool should_plug_request(struct ceph_osd_request *req)
{
	struct ceph_osd *osd = req->r_osd;
	struct ceph_spg_mapping *spg;
	struct ceph_osd_backoff *backoff;
	struct ceph_hobject_id hoid;

	spg = lookup_spg_mapping(&osd->o_backoff_mappings, &req->r_t.spgid);
	if (!spg)
		return false;

	hoid_fill_from_target(&hoid, &req->r_t);
	backoff = lookup_containing_backoff(&spg->backoffs, &hoid);
	if (!backoff)
		return false;

	dout("%s req %p tid %llu backoff osd%d spgid %llu.%xs%d id %llu\n",
	     __func__, req, req->r_tid, osd->o_osd, backoff->spgid.pgid.pool,
	     backoff->spgid.pgid.seed, backoff->spgid.shard, backoff->id);
	return true;
}

static void setup_request_data(struct ceph_osd_request *req,
			       struct ceph_msg *msg)
{
	u32 data_len = 0;
	int i;

	if (!list_empty(&msg->data))
		return;

	WARN_ON(msg->data_length);
	for (i = 0; i < req->r_num_ops; i++) {
		struct ceph_osd_req_op *op = &req->r_ops[i];

		switch (op->op) {
		/* request */
		case CEPH_OSD_OP_WRITE:
		case CEPH_OSD_OP_WRITEFULL:
			WARN_ON(op->indata_len != op->extent.length);
			ceph_osdc_msg_data_add(msg, &op->extent.osd_data);
			break;
		case CEPH_OSD_OP_SETXATTR:
		case CEPH_OSD_OP_CMPXATTR:
			WARN_ON(op->indata_len != op->xattr.name_len +
						  op->xattr.value_len);
			ceph_osdc_msg_data_add(msg, &op->xattr.osd_data);
			break;
		case CEPH_OSD_OP_NOTIFY_ACK:
			ceph_osdc_msg_data_add(msg,
					       &op->notify_ack.request_data);
			break;

		/* reply */
		case CEPH_OSD_OP_STAT:
			ceph_osdc_msg_data_add(req->r_reply,
					       &op->raw_data_in);
			break;
		case CEPH_OSD_OP_READ:
			ceph_osdc_msg_data_add(req->r_reply,
					       &op->extent.osd_data);
			break;
		case CEPH_OSD_OP_LIST_WATCHERS:
			ceph_osdc_msg_data_add(req->r_reply,
					       &op->list_watchers.response_data);
			break;

		/* both */
		case CEPH_OSD_OP_CALL:
			WARN_ON(op->indata_len != op->cls.class_len +
						  op->cls.method_len +
						  op->cls.indata_len);
			ceph_osdc_msg_data_add(msg, &op->cls.request_info);
			/* optional, can be NONE */
			ceph_osdc_msg_data_add(msg, &op->cls.request_data);
			/* optional, can be NONE */
			ceph_osdc_msg_data_add(req->r_reply,
					       &op->cls.response_data);
			break;
		case CEPH_OSD_OP_NOTIFY:
			ceph_osdc_msg_data_add(msg,
					       &op->notify.request_data);
			ceph_osdc_msg_data_add(req->r_reply,
					       &op->notify.response_data);
			break;
		}

		data_len += op->indata_len;
	}

	WARN_ON(data_len != msg->data_length);
}

static void encode_pgid(void **p, const struct ceph_pg *pgid)
{
	ceph_encode_8(p, 1);
	ceph_encode_64(p, pgid->pool);
	ceph_encode_32(p, pgid->seed);
	ceph_encode_32(p, -1); /* preferred */
}

static void encode_spgid(void **p, const struct ceph_spg *spgid)
{
	ceph_start_encoding(p, 1, 1, CEPH_PGID_ENCODING_LEN + 1);
	encode_pgid(p, &spgid->pgid);
	ceph_encode_8(p, spgid->shard);
}

static void encode_oloc(void **p, void *end,
			const struct ceph_object_locator *oloc)
{
	ceph_start_encoding(p, 5, 4, ceph_oloc_encoding_size(oloc));
	ceph_encode_64(p, oloc->pool);
	ceph_encode_32(p, -1); /* preferred */
	ceph_encode_32(p, 0);  /* key len */
	if (oloc->pool_ns)
		ceph_encode_string(p, end, oloc->pool_ns->str,
				   oloc->pool_ns->len);
	else
		ceph_encode_32(p, 0);
}

static void encode_request_partial(struct ceph_osd_request *req,
				   struct ceph_msg *msg)
{
	void *p = msg->front.iov_base;
	void *const end = p + msg->front_alloc_len;
	u32 data_len = 0;
	int i;

	if (req->r_flags & CEPH_OSD_FLAG_WRITE) {
		/* snapshots aren't writeable */
		WARN_ON(req->r_snapid != CEPH_NOSNAP);
	} else {
		WARN_ON(req->r_mtime.tv_sec || req->r_mtime.tv_nsec ||
			req->r_data_offset || req->r_snapc);
	}

	setup_request_data(req, msg);

	encode_spgid(&p, &req->r_t.spgid); /* actual spg */
	ceph_encode_32(&p, req->r_t.pgid.seed); /* raw hash */
	ceph_encode_32(&p, req->r_osdc->osdmap->epoch);
	ceph_encode_32(&p, req->r_flags);

	/* reqid */
	ceph_start_encoding(&p, 2, 2, sizeof(struct ceph_osd_reqid));
	memset(p, 0, sizeof(struct ceph_osd_reqid));
	p += sizeof(struct ceph_osd_reqid);

	/* trace */
	memset(p, 0, sizeof(struct ceph_blkin_trace_info));
	p += sizeof(struct ceph_blkin_trace_info);

	ceph_encode_32(&p, 0); /* client_inc, always 0 */
	ceph_encode_timespec64(p, &req->r_mtime);
	p += sizeof(struct ceph_timespec);

	encode_oloc(&p, end, &req->r_t.target_oloc);
	ceph_encode_string(&p, end, req->r_t.target_oid.name,
			   req->r_t.target_oid.name_len);

	/* ops, can imply data */
	ceph_encode_16(&p, req->r_num_ops);
	for (i = 0; i < req->r_num_ops; i++) {
		data_len += osd_req_encode_op(p, &req->r_ops[i]);
		p += sizeof(struct ceph_osd_op);
	}

	ceph_encode_64(&p, req->r_snapid); /* snapid */
	if (req->r_snapc) {
		ceph_encode_64(&p, req->r_snapc->seq);
		ceph_encode_32(&p, req->r_snapc->num_snaps);
		for (i = 0; i < req->r_snapc->num_snaps; i++)
			ceph_encode_64(&p, req->r_snapc->snaps[i]);
	} else {
		ceph_encode_64(&p, 0); /* snap_seq */
		ceph_encode_32(&p, 0); /* snaps len */
	}

	ceph_encode_32(&p, req->r_attempts); /* retry_attempt */
	BUG_ON(p > end - 8); /* space for features */

	msg->hdr.version = cpu_to_le16(8); /* MOSDOp v8 */
	/* front_len is finalized in encode_request_finish() */
	msg->front.iov_len = p - msg->front.iov_base;
	msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
	msg->hdr.data_len = cpu_to_le32(data_len);
	/*
	 * The header "data_off" is a hint to the receiver allowing it
	 * to align received data into its buffers such that there's no
	 * need to re-copy it before writing it to disk (direct I/O).
	 */
	msg->hdr.data_off = cpu_to_le16(req->r_data_offset);

	dout("%s req %p msg %p oid %s oid_len %d\n", __func__, req, msg,
	     req->r_t.target_oid.name, req->r_t.target_oid.name_len);
}

static void encode_request_finish(struct ceph_msg *msg)
{
	void *p = msg->front.iov_base;
	void *const partial_end = p + msg->front.iov_len;
	void *const end = p + msg->front_alloc_len;

	if (CEPH_HAVE_FEATURE(msg->con->peer_features, RESEND_ON_SPLIT)) {
		/* luminous OSD -- encode features and be done */
		p = partial_end;
		ceph_encode_64(&p, msg->con->peer_features);
	} else {
		struct {
			char spgid[CEPH_ENCODING_START_BLK_LEN +
				   CEPH_PGID_ENCODING_LEN + 1];
			__le32 hash;
			__le32 epoch;
			__le32 flags;
			char reqid[CEPH_ENCODING_START_BLK_LEN +
				   sizeof(struct ceph_osd_reqid)];
			char trace[sizeof(struct ceph_blkin_trace_info)];
			__le32 client_inc;
			struct ceph_timespec mtime;
		} __packed head;
		struct ceph_pg pgid;
		void *oloc, *oid, *tail;
		int oloc_len, oid_len, tail_len;
		int len;

		/*
		 * Pre-luminous OSD -- reencode v8 into v4 using @head
		 * as a temporary buffer.  Encode the raw PG; the rest
		 * is just a matter of moving oloc, oid and tail blobs
		 * around.
		 */
		memcpy(&head, p, sizeof(head));
		p += sizeof(head);

		oloc = p;
		p += CEPH_ENCODING_START_BLK_LEN;
		pgid.pool = ceph_decode_64(&p);
		p += 4 + 4; /* preferred, key len */
		len = ceph_decode_32(&p);
		p += len;   /* nspace */
		oloc_len = p - oloc;

		oid = p;
		len = ceph_decode_32(&p);
		p += len;
		oid_len = p - oid;

		tail = p;
		tail_len = partial_end - p;

		p = msg->front.iov_base;
		ceph_encode_copy(&p, &head.client_inc, sizeof(head.client_inc));
		ceph_encode_copy(&p, &head.epoch, sizeof(head.epoch));
		ceph_encode_copy(&p, &head.flags, sizeof(head.flags));
		ceph_encode_copy(&p, &head.mtime, sizeof(head.mtime));

		/* reassert_version */
		memset(p, 0, sizeof(struct ceph_eversion));
		p += sizeof(struct ceph_eversion);

		BUG_ON(p >= oloc);
		memmove(p, oloc, oloc_len);
		p += oloc_len;

		pgid.seed = le32_to_cpu(head.hash);
		encode_pgid(&p, &pgid); /* raw pg */

		BUG_ON(p >= oid);
		memmove(p, oid, oid_len);
		p += oid_len;

		/* tail -- ops, snapid, snapc, retry_attempt */
		BUG_ON(p >= tail);
		memmove(p, tail, tail_len);
		p += tail_len;

		msg->hdr.version = cpu_to_le16(4); /* MOSDOp v4 */
	}

	BUG_ON(p > end);
	msg->front.iov_len = p - msg->front.iov_base;
	msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);

	dout("%s msg %p tid %llu %u+%u+%u v%d\n", __func__, msg,
	     le64_to_cpu(msg->hdr.tid), le32_to_cpu(msg->hdr.front_len),
	     le32_to_cpu(msg->hdr.middle_len), le32_to_cpu(msg->hdr.data_len),
	     le16_to_cpu(msg->hdr.version));
}

/*
 * @req has to be assigned a tid and registered.
 */
static void send_request(struct ceph_osd_request *req)
{
	struct ceph_osd *osd = req->r_osd;

	verify_osd_locked(osd);
	WARN_ON(osd->o_osd != req->r_t.osd);

	/* backoff? */
	if (should_plug_request(req))
		return;

	/*
	 * We may have a previously queued request message hanging
	 * around.  Cancel it to avoid corrupting the msgr.
	 */
	if (req->r_sent)
		ceph_msg_revoke(req->r_request);

	req->r_flags |= CEPH_OSD_FLAG_KNOWN_REDIR;
	if (req->r_attempts)
		req->r_flags |= CEPH_OSD_FLAG_RETRY;
	else
		WARN_ON(req->r_flags & CEPH_OSD_FLAG_RETRY);

	encode_request_partial(req, req->r_request);

	dout("%s req %p tid %llu to pgid %llu.%x spgid %llu.%xs%d osd%d e%u flags 0x%x attempt %d\n",
	     __func__, req, req->r_tid, req->r_t.pgid.pool, req->r_t.pgid.seed,
	     req->r_t.spgid.pgid.pool, req->r_t.spgid.pgid.seed,
	     req->r_t.spgid.shard, osd->o_osd, req->r_t.epoch, req->r_flags,
	     req->r_attempts);

	req->r_t.paused = false;
	req->r_stamp = jiffies;
	req->r_attempts++;

	req->r_sent = osd->o_incarnation;
	req->r_request->hdr.tid = cpu_to_le64(req->r_tid);
	ceph_con_send(&osd->o_con, ceph_msg_get(req->r_request));
}

static void maybe_request_map(struct ceph_osd_client *osdc)
{
	bool continuous = false;

	verify_osdc_locked(osdc);
	WARN_ON(!osdc->osdmap->epoch);

	if (ceph_osdmap_flag(osdc, CEPH_OSDMAP_FULL) ||
	    ceph_osdmap_flag(osdc, CEPH_OSDMAP_PAUSERD) ||
	    ceph_osdmap_flag(osdc, CEPH_OSDMAP_PAUSEWR)) {
		dout("%s osdc %p continuous\n", __func__, osdc);
		continuous = true;
	} else {
		dout("%s osdc %p onetime\n", __func__, osdc);
	}

	if (ceph_monc_want_map(&osdc->client->monc, CEPH_SUB_OSDMAP,
			       osdc->osdmap->epoch + 1, continuous))
		ceph_monc_renew_subs(&osdc->client->monc);
}

static void complete_request(struct ceph_osd_request *req, int err);
static void send_map_check(struct ceph_osd_request *req);

static void __submit_request(struct ceph_osd_request *req, bool wrlocked)
{
	struct ceph_osd_client *osdc = req->r_osdc;
	struct ceph_osd *osd;
	enum calc_target_result ct_res;
	int err = 0;
	bool need_send = false;
	bool promoted = false;

	WARN_ON(req->r_tid);
	dout("%s req %p wrlocked %d\n", __func__, req, wrlocked);

again:
	ct_res = calc_target(osdc, &req->r_t, NULL, false);
	if (ct_res == CALC_TARGET_POOL_DNE && !wrlocked)
		goto promote;

	osd = lookup_create_osd(osdc, req->r_t.osd, wrlocked);
	if (IS_ERR(osd)) {
		WARN_ON(PTR_ERR(osd) != -EAGAIN || wrlocked);
		goto promote;
	}

	if (osdc->abort_err) {
		dout("req %p abort_err %d\n", req, osdc->abort_err);
		err = osdc->abort_err;
	} else if (osdc->osdmap->epoch < osdc->epoch_barrier) {
		dout("req %p epoch %u barrier %u\n", req, osdc->osdmap->epoch,
		     osdc->epoch_barrier);
		req->r_t.paused = true;
		maybe_request_map(osdc);
	} else if ((req->r_flags & CEPH_OSD_FLAG_WRITE) &&
		   ceph_osdmap_flag(osdc, CEPH_OSDMAP_PAUSEWR)) {
		dout("req %p pausewr\n", req);
		req->r_t.paused = true;
		maybe_request_map(osdc);
	} else if ((req->r_flags & CEPH_OSD_FLAG_READ) &&
		   ceph_osdmap_flag(osdc, CEPH_OSDMAP_PAUSERD)) {
		dout("req %p pauserd\n", req);
		req->r_t.paused = true;
		maybe_request_map(osdc);
	} else if ((req->r_flags & CEPH_OSD_FLAG_WRITE) &&
		   !(req->r_flags & (CEPH_OSD_FLAG_FULL_TRY |
				     CEPH_OSD_FLAG_FULL_FORCE)) &&
		   (ceph_osdmap_flag(osdc, CEPH_OSDMAP_FULL) ||
		    pool_full(osdc, req->r_t.base_oloc.pool))) {
		dout("req %p full/pool_full\n", req);
		if (osdc->abort_on_full) {
			err = -ENOSPC;
		} else {
			pr_warn_ratelimited("FULL or reached pool quota\n");
			req->r_t.paused = true;
			maybe_request_map(osdc);
		}
	} else if (!osd_homeless(osd)) {
		need_send = true;
	} else {
		maybe_request_map(osdc);
	}

	mutex_lock(&osd->lock);
	/*
	 * Assign the tid atomically with send_request() to protect
	 * multiple writes to the same object from racing with each
	 * other, resulting in out of order ops on the OSDs.
	 */
	req->r_tid = atomic64_inc_return(&osdc->last_tid);
	link_request(osd, req);
	if (need_send)
		send_request(req);
	else if (err)
		complete_request(req, err);
	mutex_unlock(&osd->lock);

	if (!err && ct_res == CALC_TARGET_POOL_DNE)
		send_map_check(req);

	if (promoted)
		downgrade_write(&osdc->lock);
	return;

promote:
	up_read(&osdc->lock);
	down_write(&osdc->lock);
	wrlocked = true;
	promoted = true;
	goto again;
}

static void account_request(struct ceph_osd_request *req)
{
	WARN_ON(req->r_flags & (CEPH_OSD_FLAG_ACK | CEPH_OSD_FLAG_ONDISK));
	WARN_ON(!(req->r_flags & (CEPH_OSD_FLAG_READ | CEPH_OSD_FLAG_WRITE)));

	req->r_flags |= CEPH_OSD_FLAG_ONDISK;
	atomic_inc(&req->r_osdc->num_requests);

	req->r_start_stamp = jiffies;
}

static void submit_request(struct ceph_osd_request *req, bool wrlocked)
{
	ceph_osdc_get_request(req);
	account_request(req);
	__submit_request(req, wrlocked);
}

static void finish_request(struct ceph_osd_request *req)
{
	struct ceph_osd_client *osdc = req->r_osdc;

	WARN_ON(lookup_request_mc(&osdc->map_checks, req->r_tid));
	dout("%s req %p tid %llu\n", __func__, req, req->r_tid);

	if (req->r_osd)
		unlink_request(req->r_osd, req);
	atomic_dec(&osdc->num_requests);

	/*
	 * If an OSD has failed or returned and a request has been sent
	 * twice, it's possible to get a reply and end up here while the
	 * request message is queued for delivery.  We will ignore the
	 * reply, so not a big deal, but better to try and catch it.
	 */
	ceph_msg_revoke(req->r_request);
	ceph_msg_revoke_incoming(req->r_reply);
}

static void __complete_request(struct ceph_osd_request *req)
{
	dout("%s req %p tid %llu cb %pf result %d\n", __func__, req,
	     req->r_tid, req->r_callback, req->r_result);

	if (req->r_callback)
		req->r_callback(req);
	complete_all(&req->r_completion);
	ceph_osdc_put_request(req);
}

static void complete_request_workfn(struct work_struct *work)
{
	struct ceph_osd_request *req =
	    container_of(work, struct ceph_osd_request, r_complete_work);

	__complete_request(req);
}

/*
 * This is open-coded in handle_reply().
 */
static void complete_request(struct ceph_osd_request *req, int err)
{
	dout("%s req %p tid %llu err %d\n", __func__, req, req->r_tid, err);

	req->r_result = err;
	finish_request(req);

	INIT_WORK(&req->r_complete_work, complete_request_workfn);
	queue_work(req->r_osdc->completion_wq, &req->r_complete_work);
}

static void cancel_map_check(struct ceph_osd_request *req)
{
	struct ceph_osd_client *osdc = req->r_osdc;
	struct ceph_osd_request *lookup_req;

	verify_osdc_wrlocked(osdc);

	lookup_req = lookup_request_mc(&osdc->map_checks, req->r_tid);
	if (!lookup_req)
		return;

	WARN_ON(lookup_req != req);
	erase_request_mc(&osdc->map_checks, req);
	ceph_osdc_put_request(req);
}

static void cancel_request(struct ceph_osd_request *req)
{
	dout("%s req %p tid %llu\n", __func__, req, req->r_tid);

	cancel_map_check(req);
	finish_request(req);
	complete_all(&req->r_completion);
	ceph_osdc_put_request(req);
}

static void abort_request(struct ceph_osd_request *req, int err)
{
	dout("%s req %p tid %llu err %d\n", __func__, req, req->r_tid, err);

	cancel_map_check(req);
	complete_request(req, err);
}

static int abort_fn(struct ceph_osd_request *req, void *arg)
{
	int err = *(int *)arg;

	abort_request(req, err);
	return 0; /* continue iteration */
}

/*
 * Abort all in-flight requests with @err and arrange for all future
 * requests to be failed immediately.
 */
void ceph_osdc_abort_requests(struct ceph_osd_client *osdc, int err)
{
	dout("%s osdc %p err %d\n", __func__, osdc, err);
	down_write(&osdc->lock);
	for_each_request(osdc, abort_fn, &err);
	osdc->abort_err = err;
	up_write(&osdc->lock);
}
EXPORT_SYMBOL(ceph_osdc_abort_requests);

static void update_epoch_barrier(struct ceph_osd_client *osdc, u32 eb)
{
	if (likely(eb > osdc->epoch_barrier)) {
		dout("updating epoch_barrier from %u to %u\n",
				osdc->epoch_barrier, eb);
		osdc->epoch_barrier = eb;
		/* Request map if we're not to the barrier yet */
		if (eb > osdc->osdmap->epoch)
			maybe_request_map(osdc);
	}
}

void ceph_osdc_update_epoch_barrier(struct ceph_osd_client *osdc, u32 eb)
{
	down_read(&osdc->lock);
	if (unlikely(eb > osdc->epoch_barrier)) {
		up_read(&osdc->lock);
		down_write(&osdc->lock);
		update_epoch_barrier(osdc, eb);
		up_write(&osdc->lock);
	} else {
		up_read(&osdc->lock);
	}
}
EXPORT_SYMBOL(ceph_osdc_update_epoch_barrier);

/*
 * We can end up releasing caps as a result of abort_request().
 * In that case, we probably want to ensure that the cap release message
 * has an updated epoch barrier in it, so set the epoch barrier prior to
 * aborting the first request.
 */
static int abort_on_full_fn(struct ceph_osd_request *req, void *arg)
{
	struct ceph_osd_client *osdc = req->r_osdc;
	bool *victims = arg;

	if ((req->r_flags & CEPH_OSD_FLAG_WRITE) &&
	    (ceph_osdmap_flag(osdc, CEPH_OSDMAP_FULL) ||
	     pool_full(osdc, req->r_t.base_oloc.pool))) {
		if (!*victims) {
			update_epoch_barrier(osdc, osdc->osdmap->epoch);
			*victims = true;
		}
		abort_request(req, -ENOSPC);
	}

	return 0; /* continue iteration */
}

/*
 * Drop all pending requests that are stalled waiting on a full condition to
 * clear, and complete them with ENOSPC as the return code. Set the
 * osdc->epoch_barrier to the latest map epoch that we've seen if any were
 * cancelled.
 */
static void ceph_osdc_abort_on_full(struct ceph_osd_client *osdc)
{
	bool victims = false;

	if (osdc->abort_on_full &&
	    (ceph_osdmap_flag(osdc, CEPH_OSDMAP_FULL) || have_pool_full(osdc)))
		for_each_request(osdc, abort_on_full_fn, &victims);
}

static void check_pool_dne(struct ceph_osd_request *req)
{
	struct ceph_osd_client *osdc = req->r_osdc;
	struct ceph_osdmap *map = osdc->osdmap;

	verify_osdc_wrlocked(osdc);
	WARN_ON(!map->epoch);

	if (req->r_attempts) {
		/*
		 * We sent a request earlier, which means that
		 * previously the pool existed, and now it does not
		 * (i.e., it was deleted).
		 */
		req->r_map_dne_bound = map->epoch;
		dout("%s req %p tid %llu pool disappeared\n", __func__, req,
		     req->r_tid);
	} else {
		dout("%s req %p tid %llu map_dne_bound %u have %u\n", __func__,
		     req, req->r_tid, req->r_map_dne_bound, map->epoch);
	}

	if (req->r_map_dne_bound) {
		if (map->epoch >= req->r_map_dne_bound) {
			/* we had a new enough map */
			pr_info_ratelimited("tid %llu pool does not exist\n",
					    req->r_tid);
			complete_request(req, -ENOENT);
		}
	} else {
		send_map_check(req);
	}
}

static void map_check_cb(struct ceph_mon_generic_request *greq)
{
	struct ceph_osd_client *osdc = &greq->monc->client->osdc;
	struct ceph_osd_request *req;
	u64 tid = greq->private_data;

	WARN_ON(greq->result || !greq->u.newest);

	down_write(&osdc->lock);
	req = lookup_request_mc(&osdc->map_checks, tid);
	if (!req) {
		dout("%s tid %llu dne\n", __func__, tid);
		goto out_unlock;
	}

	dout("%s req %p tid %llu map_dne_bound %u newest %llu\n", __func__,
	     req, req->r_tid, req->r_map_dne_bound, greq->u.newest);
	if (!req->r_map_dne_bound)
		req->r_map_dne_bound = greq->u.newest;
	erase_request_mc(&osdc->map_checks, req);
	check_pool_dne(req);

	ceph_osdc_put_request(req);
out_unlock:
	up_write(&osdc->lock);
}

static void send_map_check(struct ceph_osd_request *req)
{
	struct ceph_osd_client *osdc = req->r_osdc;
	struct ceph_osd_request *lookup_req;
	int ret;

	verify_osdc_wrlocked(osdc);

	lookup_req = lookup_request_mc(&osdc->map_checks, req->r_tid);
	if (lookup_req) {
		WARN_ON(lookup_req != req);
		return;
	}

	ceph_osdc_get_request(req);
	insert_request_mc(&osdc->map_checks, req);
	ret = ceph_monc_get_version_async(&osdc->client->monc, "osdmap",
					  map_check_cb, req->r_tid);
	WARN_ON(ret);
}

/*
 * lingering requests, watch/notify v2 infrastructure
 */
static void linger_release(struct kref *kref)
{
	struct ceph_osd_linger_request *lreq =
	    container_of(kref, struct ceph_osd_linger_request, kref);

	dout("%s lreq %p reg_req %p ping_req %p\n", __func__, lreq,
	     lreq->reg_req, lreq->ping_req);
	WARN_ON(!RB_EMPTY_NODE(&lreq->node));
	WARN_ON(!RB_EMPTY_NODE(&lreq->osdc_node));
	WARN_ON(!RB_EMPTY_NODE(&lreq->mc_node));
	WARN_ON(!list_empty(&lreq->scan_item));
	WARN_ON(!list_empty(&lreq->pending_lworks));
	WARN_ON(lreq->osd);

	if (lreq->reg_req)
		ceph_osdc_put_request(lreq->reg_req);
	if (lreq->ping_req)
		ceph_osdc_put_request(lreq->ping_req);
	target_destroy(&lreq->t);
	kfree(lreq);
}

static void linger_put(struct ceph_osd_linger_request *lreq)
{
	if (lreq)
		kref_put(&lreq->kref, linger_release);
}

static struct ceph_osd_linger_request *
linger_get(struct ceph_osd_linger_request *lreq)
{
	kref_get(&lreq->kref);
	return lreq;
}

static struct ceph_osd_linger_request *
linger_alloc(struct ceph_osd_client *osdc)
{
	struct ceph_osd_linger_request *lreq;

	lreq = kzalloc(sizeof(*lreq), GFP_NOIO);
	if (!lreq)
		return NULL;

	kref_init(&lreq->kref);
	mutex_init(&lreq->lock);
	RB_CLEAR_NODE(&lreq->node);
	RB_CLEAR_NODE(&lreq->osdc_node);
	RB_CLEAR_NODE(&lreq->mc_node);
	INIT_LIST_HEAD(&lreq->scan_item);
	INIT_LIST_HEAD(&lreq->pending_lworks);
	init_completion(&lreq->reg_commit_wait);
	init_completion(&lreq->notify_finish_wait);

	lreq->osdc = osdc;
	target_init(&lreq->t);

	dout("%s lreq %p\n", __func__, lreq);
	return lreq;
}

DEFINE_RB_INSDEL_FUNCS(linger, struct ceph_osd_linger_request, linger_id, node)
DEFINE_RB_FUNCS(linger_osdc, struct ceph_osd_linger_request, linger_id, osdc_node)
DEFINE_RB_FUNCS(linger_mc, struct ceph_osd_linger_request, linger_id, mc_node)

/*
 * Create linger request <-> OSD session relation.
 *
 * @lreq has to be registered, @osd may be homeless.
 */
static void link_linger(struct ceph_osd *osd,
			struct ceph_osd_linger_request *lreq)
{
	verify_osd_locked(osd);
	WARN_ON(!lreq->linger_id || lreq->osd);
	dout("%s osd %p osd%d lreq %p linger_id %llu\n", __func__, osd,
	     osd->o_osd, lreq, lreq->linger_id);

	if (!osd_homeless(osd))
		__remove_osd_from_lru(osd);
	else
		atomic_inc(&osd->o_osdc->num_homeless);

	get_osd(osd);
	insert_linger(&osd->o_linger_requests, lreq);
	lreq->osd = osd;
}

static void unlink_linger(struct ceph_osd *osd,
			  struct ceph_osd_linger_request *lreq)
{
	verify_osd_locked(osd);
	WARN_ON(lreq->osd != osd);
	dout("%s osd %p osd%d lreq %p linger_id %llu\n", __func__, osd,
	     osd->o_osd, lreq, lreq->linger_id);

	lreq->osd = NULL;
	erase_linger(&osd->o_linger_requests, lreq);
	put_osd(osd);

	if (!osd_homeless(osd))
		maybe_move_osd_to_lru(osd);
	else
		atomic_dec(&osd->o_osdc->num_homeless);
}

static bool __linger_registered(struct ceph_osd_linger_request *lreq)
{
	verify_osdc_locked(lreq->osdc);

	return !RB_EMPTY_NODE(&lreq->osdc_node);
}

static bool linger_registered(struct ceph_osd_linger_request *lreq)
{
	struct ceph_osd_client *osdc = lreq->osdc;
	bool registered;

	down_read(&osdc->lock);
	registered = __linger_registered(lreq);
	up_read(&osdc->lock);

	return registered;
}

static void linger_register(struct ceph_osd_linger_request *lreq)
{
	struct ceph_osd_client *osdc = lreq->osdc;

	verify_osdc_wrlocked(osdc);
	WARN_ON(lreq->linger_id);

	linger_get(lreq);
	lreq->linger_id = ++osdc->last_linger_id;
	insert_linger_osdc(&osdc->linger_requests, lreq);
}

static void linger_unregister(struct ceph_osd_linger_request *lreq)
{
	struct ceph_osd_client *osdc = lreq->osdc;

	verify_osdc_wrlocked(osdc);

	erase_linger_osdc(&osdc->linger_requests, lreq);
	linger_put(lreq);
}

static void cancel_linger_request(struct ceph_osd_request *req)
{
	struct ceph_osd_linger_request *lreq = req->r_priv;

	WARN_ON(!req->r_linger);
	cancel_request(req);
	linger_put(lreq);
}

struct linger_work {
	struct work_struct work;
	struct ceph_osd_linger_request *lreq;
	struct list_head pending_item;
	unsigned long queued_stamp;

	union {
		struct {
			u64 notify_id;
			u64 notifier_id;
			void *payload; /* points into @msg front */
			size_t payload_len;

			struct ceph_msg *msg; /* for ceph_msg_put() */
		} notify;
		struct {
			int err;
		} error;
	};
};

static struct linger_work *lwork_alloc(struct ceph_osd_linger_request *lreq,
				       work_func_t workfn)
{
	struct linger_work *lwork;

	lwork = kzalloc(sizeof(*lwork), GFP_NOIO);
	if (!lwork)
		return NULL;

	INIT_WORK(&lwork->work, workfn);
	INIT_LIST_HEAD(&lwork->pending_item);
	lwork->lreq = linger_get(lreq);

	return lwork;
}

static void lwork_free(struct linger_work *lwork)
{
	struct ceph_osd_linger_request *lreq = lwork->lreq;

	mutex_lock(&lreq->lock);
	list_del(&lwork->pending_item);
	mutex_unlock(&lreq->lock);

	linger_put(lreq);
	kfree(lwork);
}

static void lwork_queue(struct linger_work *lwork)
{
	struct ceph_osd_linger_request *lreq = lwork->lreq;
	struct ceph_osd_client *osdc = lreq->osdc;

	verify_lreq_locked(lreq);
	WARN_ON(!list_empty(&lwork->pending_item));

	lwork->queued_stamp = jiffies;
	list_add_tail(&lwork->pending_item, &lreq->pending_lworks);
	queue_work(osdc->notify_wq, &lwork->work);
}

static void do_watch_notify(struct work_struct *w)
{
	struct linger_work *lwork = container_of(w, struct linger_work, work);
	struct ceph_osd_linger_request *lreq = lwork->lreq;

	if (!linger_registered(lreq)) {
		dout("%s lreq %p not registered\n", __func__, lreq);
		goto out;
	}

	WARN_ON(!lreq->is_watch);
	dout("%s lreq %p notify_id %llu notifier_id %llu payload_len %zu\n",
	     __func__, lreq, lwork->notify.notify_id, lwork->notify.notifier_id,
	     lwork->notify.payload_len);
	lreq->wcb(lreq->data, lwork->notify.notify_id, lreq->linger_id,
		  lwork->notify.notifier_id, lwork->notify.payload,
		  lwork->notify.payload_len);

out:
	ceph_msg_put(lwork->notify.msg);
	lwork_free(lwork);
}

static void do_watch_error(struct work_struct *w)
{
	struct linger_work *lwork = container_of(w, struct linger_work, work);
	struct ceph_osd_linger_request *lreq = lwork->lreq;

	if (!linger_registered(lreq)) {
		dout("%s lreq %p not registered\n", __func__, lreq);
		goto out;
	}

	dout("%s lreq %p err %d\n", __func__, lreq, lwork->error.err);
	lreq->errcb(lreq->data, lreq->linger_id, lwork->error.err);

out:
	lwork_free(lwork);
}

static void queue_watch_error(struct ceph_osd_linger_request *lreq)
{
	struct linger_work *lwork;

	lwork = lwork_alloc(lreq, do_watch_error);
	if (!lwork) {
		pr_err("failed to allocate error-lwork\n");
		return;
	}

	lwork->error.err = lreq->last_error;
	lwork_queue(lwork);
}

static void linger_reg_commit_complete(struct ceph_osd_linger_request *lreq,
				       int result)
{
	if (!completion_done(&lreq->reg_commit_wait)) {
		lreq->reg_commit_error = (result <= 0 ? result : 0);
		complete_all(&lreq->reg_commit_wait);
	}
}

static void linger_commit_cb(struct ceph_osd_request *req)
{
	struct ceph_osd_linger_request *lreq = req->r_priv;

	mutex_lock(&lreq->lock);
	dout("%s lreq %p linger_id %llu result %d\n", __func__, lreq,
	     lreq->linger_id, req->r_result);
	linger_reg_commit_complete(lreq, req->r_result);
	lreq->committed = true;

	if (!lreq->is_watch) {
		struct ceph_osd_data *osd_data =
		    osd_req_op_data(req, 0, notify, response_data);
		void *p = page_address(osd_data->pages[0]);

		WARN_ON(req->r_ops[0].op != CEPH_OSD_OP_NOTIFY ||
			osd_data->type != CEPH_OSD_DATA_TYPE_PAGES);

		/* make note of the notify_id */
		if (req->r_ops[0].outdata_len >= sizeof(u64)) {
			lreq->notify_id = ceph_decode_64(&p);
			dout("lreq %p notify_id %llu\n", lreq,
			     lreq->notify_id);
		} else {
			dout("lreq %p no notify_id\n", lreq);
		}
	}

	mutex_unlock(&lreq->lock);
	linger_put(lreq);
}

static int normalize_watch_error(int err)
{
	/*
	 * Translate ENOENT -> ENOTCONN so that a delete->disconnection
	 * notification and a failure to reconnect because we raced with
	 * the delete appear the same to the user.
	 */
	if (err == -ENOENT)
		err = -ENOTCONN;

	return err;
}

static void linger_reconnect_cb(struct ceph_osd_request *req)
{
	struct ceph_osd_linger_request *lreq = req->r_priv;

	mutex_lock(&lreq->lock);
	dout("%s lreq %p linger_id %llu result %d last_error %d\n", __func__,
	     lreq, lreq->linger_id, req->r_result, lreq->last_error);
	if (req->r_result < 0) {
		if (!lreq->last_error) {
			lreq->last_error = normalize_watch_error(req->r_result);
			queue_watch_error(lreq);
		}
	}

	mutex_unlock(&lreq->lock);
	linger_put(lreq);
}

static void send_linger(struct ceph_osd_linger_request *lreq)
{
	struct ceph_osd_request *req = lreq->reg_req;
	struct ceph_osd_req_op *op = &req->r_ops[0];

	verify_osdc_wrlocked(req->r_osdc);
	dout("%s lreq %p linger_id %llu\n", __func__, lreq, lreq->linger_id);

	if (req->r_osd)
		cancel_linger_request(req);

	request_reinit(req);
	ceph_oid_copy(&req->r_base_oid, &lreq->t.base_oid);
	ceph_oloc_copy(&req->r_base_oloc, &lreq->t.base_oloc);
	req->r_flags = lreq->t.flags;
	req->r_mtime = lreq->mtime;

	mutex_lock(&lreq->lock);
	if (lreq->is_watch && lreq->committed) {
		WARN_ON(op->op != CEPH_OSD_OP_WATCH ||
			op->watch.cookie != lreq->linger_id);
		op->watch.op = CEPH_OSD_WATCH_OP_RECONNECT;
		op->watch.gen = ++lreq->register_gen;
		dout("lreq %p reconnect register_gen %u\n", lreq,
		     op->watch.gen);
		req->r_callback = linger_reconnect_cb;
	} else {
		if (!lreq->is_watch)
			lreq->notify_id = 0;
		else
			WARN_ON(op->watch.op != CEPH_OSD_WATCH_OP_WATCH);
		dout("lreq %p register\n", lreq);
		req->r_callback = linger_commit_cb;
	}
	mutex_unlock(&lreq->lock);

	req->r_priv = linger_get(lreq);
	req->r_linger = true;

	submit_request(req, true);
}

static void linger_ping_cb(struct ceph_osd_request *req)
{
	struct ceph_osd_linger_request *lreq = req->r_priv;

	mutex_lock(&lreq->lock);
	dout("%s lreq %p linger_id %llu result %d ping_sent %lu last_error %d\n",
	     __func__, lreq, lreq->linger_id, req->r_result, lreq->ping_sent,
	     lreq->last_error);
	if (lreq->register_gen == req->r_ops[0].watch.gen) {
		if (!req->r_result) {
			lreq->watch_valid_thru = lreq->ping_sent;
		} else if (!lreq->last_error) {
			lreq->last_error = normalize_watch_error(req->r_result);
			queue_watch_error(lreq);
		}
	} else {
		dout("lreq %p register_gen %u ignoring old pong %u\n", lreq,
		     lreq->register_gen, req->r_ops[0].watch.gen);
	}

	mutex_unlock(&lreq->lock);
	linger_put(lreq);
}

static void send_linger_ping(struct ceph_osd_linger_request *lreq)
{
	struct ceph_osd_client *osdc = lreq->osdc;
	struct ceph_osd_request *req = lreq->ping_req;
	struct ceph_osd_req_op *op = &req->r_ops[0];

	if (ceph_osdmap_flag(osdc, CEPH_OSDMAP_PAUSERD)) {
		dout("%s PAUSERD\n", __func__);
		return;
	}

	lreq->ping_sent = jiffies;
	dout("%s lreq %p linger_id %llu ping_sent %lu register_gen %u\n",
	     __func__, lreq, lreq->linger_id, lreq->ping_sent,
	     lreq->register_gen);

	if (req->r_osd)
		cancel_linger_request(