drivers/staging/lustre/lustre/osc/osc_cl_internal.h - nest-learning-thermostat/5.7.1/linux-imx-ul - Git at Google

 /*
  * GPL HEADER START
  *
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 only,
  * as published by the Free Software Foundation.
  *
  * This program is distributed in the hope that it will be useful, but
  * WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * General Public License version 2 for more details (a copy is included
  * in the LICENSE file that accompanied this code).
  *
  * You should have received a copy of the GNU General Public License
  * version 2 along with this program; If not, see
  * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
  *
  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  * CA 95054 USA or visit www.sun.com if you need additional information or
  * have any questions.
  *
  * GPL HEADER END
  */
 /*
  * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
  * Use is subject to license terms.
  *
  * Copyright (c) 2012, Intel Corporation.
  */
 /*
  * This file is part of Lustre, http://www.lustre.org/
  * Lustre is a trademark of Sun Microsystems, Inc.
  */
 /*
  * This file is part of Lustre, http://www.lustre.org/
  * Lustre is a trademark of Sun Microsystems, Inc.
  *
  * Internal interfaces of OSC layer.
  *
  *   Author: Nikita Danilov <nikita.danilov@sun.com>
  *   Author: Jinshan Xiong <jinshan.xiong@whamcloud.com>
  */

 #ifndef OSC_CL_INTERNAL_H
 #define OSC_CL_INTERNAL_H

 #include "../../include/linux/libcfs/libcfs.h"

 #include "../include/obd.h"
 /* osc_build_res_name() */
 #include "../include/cl_object.h"
 #include "../include/lclient.h"
 #include "osc_internal.h"

 /** \defgroup osc osc
  *  @{
  */

 struct osc_extent;

 /**
  * State maintained by osc layer for each IO context.
  */
 struct osc_io {
 	/** super class */
 	struct cl_io_slice oi_cl;
 	/** true if this io is lockless. */
 	int		oi_lockless;
 	/** active extents, we know how many bytes is going to be written,
 	 * so having an active extent will prevent it from being fragmented */
 	struct osc_extent *oi_active;
 	/** partially truncated extent, we need to hold this extent to prevent
 	 * page writeback from happening. */
 	struct osc_extent *oi_trunc;

 	struct obd_info    oi_info;
 	struct obdo	oi_oa;
 	struct osc_async_cbargs {
 		bool		  opc_rpc_sent;
 		int	       opc_rc;
 		struct completion	opc_sync;
 	} oi_cbarg;
 };

 /**
  * State of transfer for osc.
  */
 struct osc_req {
 	struct cl_req_slice    or_cl;
 };

 /**
  * State maintained by osc layer for the duration of a system call.
  */
 struct osc_session {
 	struct osc_io       os_io;
 };

 #define OTI_PVEC_SIZE 64
 struct osc_thread_info {
 	struct ldlm_res_id      oti_resname;
 	ldlm_policy_data_t      oti_policy;
 	struct cl_lock_descr    oti_descr;
 	struct cl_attr	  oti_attr;
 	struct lustre_handle    oti_handle;
 	struct cl_page_list     oti_plist;
 	struct cl_io		oti_io;
 	struct cl_page	       *oti_pvec[OTI_PVEC_SIZE];
 };

 struct osc_object {
 	struct cl_object   oo_cl;
 	struct lov_oinfo  *oo_oinfo;
 	/**
 	 * True if locking against this stripe got -EUSERS.
 	 */
 	int		oo_contended;
 	unsigned long	 oo_contention_time;
 	/**
 	 * List of pages in transfer.
 	 */
 	struct list_head	 oo_inflight[CRT_NR];
 	/**
 	 * Lock, protecting ccc_object::cob_inflight, because a seat-belt is
 	 * locked during take-off and landing.
 	 */
 	spinlock_t	   oo_seatbelt;

 	/**
 	 * used by the osc to keep track of what objects to build into rpcs.
 	 * Protected by client_obd->cli_loi_list_lock.
 	 */
 	struct list_head	   oo_ready_item;
 	struct list_head	   oo_hp_ready_item;
 	struct list_head	   oo_write_item;
 	struct list_head	   oo_read_item;

 	/**
 	 * extent is a red black tree to manage (async) dirty pages.
 	 */
 	struct rb_root       oo_root;
 	/**
 	 * Manage write(dirty) extents.
 	 */
 	struct list_head	   oo_hp_exts; /* list of hp extents */
 	struct list_head	   oo_urgent_exts; /* list of writeback extents */
 	struct list_head	   oo_rpc_exts;

 	struct list_head	   oo_reading_exts;

 	atomic_t	 oo_nr_reads;
 	atomic_t	 oo_nr_writes;

 	/** Protect extent tree. Will be used to protect
 	 * oo_{read|write}_pages soon. */
 	spinlock_t	    oo_lock;
 };

 static inline void osc_object_lock(struct osc_object *obj)
 {
 	spin_lock(&obj->oo_lock);
 }

 static inline int osc_object_trylock(struct osc_object *obj)
 {
 	return spin_trylock(&obj->oo_lock);
 }

 static inline void osc_object_unlock(struct osc_object *obj)
 {
 	spin_unlock(&obj->oo_lock);
 }

 static inline int osc_object_is_locked(struct osc_object *obj)
 {
 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
 	return spin_is_locked(&obj->oo_lock);
 #else
 	/*
 	 * It is not perfect to return true all the time.
 	 * But since this function is only used for assertion
 	 * and checking, it seems OK.
 	 */
 	return 1;
 #endif
 }

 /*
  * Lock "micro-states" for osc layer.
  */
 enum osc_lock_state {
 	OLS_NEW,
 	OLS_ENQUEUED,
 	OLS_UPCALL_RECEIVED,
 	OLS_GRANTED,
 	OLS_RELEASED,
 	OLS_BLOCKED,
 	OLS_CANCELLED
 };

 /**
  * osc-private state of cl_lock.
  *
  * Interaction with DLM.
  *
  * CLIO enqueues all DLM locks through ptlrpcd (that is, in "async" mode).
  *
  * Once receive upcall is invoked, osc_lock remembers a handle of DLM lock in
  * osc_lock::ols_handle and a pointer to that lock in osc_lock::ols_lock.
  *
  * This pointer is protected through a reference, acquired by
  * osc_lock_upcall0(). Also, an additional reference is acquired by
  * ldlm_lock_addref() call protecting the lock from cancellation, until
  * osc_lock_unuse() releases it.
  *
  * Below is a description of how lock references are acquired and released
  * inside of DLM.
  *
  * - When new lock is created and enqueued to the server (ldlm_cli_enqueue())
  *      - ldlm_lock_create()
  *	  - ldlm_lock_new(): initializes a lock with 2 references. One for
  *	    the caller (released when reply from the server is received, or on
  *	    error), and another for the hash table.
  *      - ldlm_lock_addref_internal(): protects the lock from cancellation.
  *
  * - When reply is received from the server (osc_enqueue_interpret())
  *      - ldlm_cli_enqueue_fini()
  *	  - LDLM_LOCK_PUT(): releases caller reference acquired by
  *	    ldlm_lock_new().
  *	  - if (rc != 0)
  *		ldlm_lock_decref(): error case: matches ldlm_cli_enqueue().
  *      - ldlm_lock_decref(): for async locks, matches ldlm_cli_enqueue().
  *
  * - When lock is being cancelled (ldlm_lock_cancel())
  *      - ldlm_lock_destroy()
  *	  - LDLM_LOCK_PUT(): releases hash-table reference acquired by
  *	    ldlm_lock_new().
  *
  * osc_lock is detached from ldlm_lock by osc_lock_detach() that is called
  * either when lock is cancelled (osc_lock_blocking()), or when locks is
  * deleted without cancellation (e.g., from cl_locks_prune()). In the latter
  * case ldlm lock remains in memory, and can be re-attached to osc_lock in the
  * future.
  */
 struct osc_lock {
 	struct cl_lock_slice     ols_cl;
 	/** underlying DLM lock */
 	struct ldlm_lock	*ols_lock;
 	/** lock value block */
 	struct ost_lvb	   ols_lvb;
 	/** DLM flags with which osc_lock::ols_lock was enqueued */
 	__u64		    ols_flags;
 	/** osc_lock::ols_lock handle */
 	struct lustre_handle     ols_handle;
 	struct ldlm_enqueue_info ols_einfo;
 	enum osc_lock_state      ols_state;

 	/**
 	 * How many pages are using this lock for io, currently only used by
 	 * read-ahead. If non-zero, the underlying dlm lock won't be cancelled
 	 * during recovery to avoid deadlock. see bz16774.
 	 *
 	 * \see osc_page::ops_lock
 	 * \see osc_page_addref_lock(), osc_page_putref_lock()
 	 */
 	atomic_t	     ols_pageref;

 	/**
 	 * true, if ldlm_lock_addref() was called against
 	 * osc_lock::ols_lock. This is used for sanity checking.
 	 *
 	 * \see osc_lock::ols_has_ref
 	 */
 	unsigned		  ols_hold :1,
 	/**
 	 * this is much like osc_lock::ols_hold, except that this bit is
 	 * cleared _after_ reference in released in osc_lock_unuse(). This
 	 * fine distinction is needed because:
 	 *
 	 *     - if ldlm lock still has a reference, osc_ast_data_get() needs
 	 *       to return associated cl_lock (so that a flag is needed that is
 	 *       cleared after ldlm_lock_decref() returned), and
 	 *
 	 *     - ldlm_lock_decref() can invoke blocking ast (for a
 	 *       LDLM_FL_CBPENDING lock), and osc_lock functions like
 	 *       osc_lock_cancel() called from there need to know whether to
 	 *       release lock reference (so that a flag is needed that is
 	 *       cleared before ldlm_lock_decref() is called).
 	 */
 				 ols_has_ref:1,
 	/**
 	 * inherit the lockless attribute from top level cl_io.
 	 * If true, osc_lock_enqueue is able to tolerate the -EUSERS error.
 	 */
 				 ols_locklessable:1,
 	/**
 	 * set by osc_lock_use() to wait until blocking AST enters into
 	 * osc_ldlm_blocking_ast0(), so that cl_lock mutex can be used for
 	 * further synchronization.
 	 */
 				 ols_ast_wait:1,
 	/**
 	 * If the data of this lock has been flushed to server side.
 	 */
 				 ols_flush:1,
 	/**
 	 * if set, the osc_lock is a glimpse lock. For glimpse locks, we treat
 	 * the EVAVAIL error as tolerable, this will make upper logic happy
 	 * to wait all glimpse locks to each OSTs to be completed.
 	 * Glimpse lock converts to normal lock if the server lock is
 	 * granted.
 	 * Glimpse lock should be destroyed immediately after use.
 	 */
 				 ols_glimpse:1,
 	/**
 	 * For async glimpse lock.
 	 */
 				 ols_agl:1;
 	/**
 	 * IO that owns this lock. This field is used for a dead-lock
 	 * avoidance by osc_lock_enqueue_wait().
 	 *
 	 * XXX: unfortunately, the owner of a osc_lock is not unique,
 	 * the lock may have multiple users, if the lock is granted and
 	 * then matched.
 	 */
 	struct osc_io	   *ols_owner;
 };


 /**
  * Page state private for osc layer.
  */
 struct osc_page {
 	struct cl_page_slice  ops_cl;
 	/**
 	 * Page queues used by osc to detect when RPC can be formed.
 	 */
 	struct osc_async_page ops_oap;
 	/**
 	 * An offset within page from which next transfer starts. This is used
 	 * by cl_page_clip() to submit partial page transfers.
 	 */
 	int		   ops_from;
 	/**
 	 * An offset within page at which next transfer ends.
 	 *
 	 * \see osc_page::ops_from.
 	 */
 	int		   ops_to;
 	/**
 	 * Boolean, true iff page is under transfer. Used for sanity checking.
 	 */
 	unsigned	      ops_transfer_pinned:1,
 	/**
 	 * True for a `temporary page' created by read-ahead code, probably
 	 * outside of any DLM lock.
 	 */
 			      ops_temp:1,
 	/**
 	 * in LRU?
 	 */
 			      ops_in_lru:1,
 	/**
 	 * Set if the page must be transferred with OBD_BRW_SRVLOCK.
 	 */
 			      ops_srvlock:1;
 	union {
 		/**
 		 * lru page list. ops_inflight and ops_lru are exclusive so
 		 * that they can share the same data.
 		 */
 		struct list_head	      ops_lru;
 		/**
 		 * Linkage into a per-osc_object list of pages in flight. For
 		 * debugging.
 		 */
 		struct list_head	    ops_inflight;
 	};
 	/**
 	 * Thread that submitted this page for transfer. For debugging.
 	 */
 	struct task_struct	*ops_submitter;
 	/**
 	 * Submit time - the time when the page is starting RPC. For debugging.
 	 */
 	unsigned long	    ops_submit_time;

 	/**
 	 * A lock of which we hold a reference covers this page. Only used by
 	 * read-ahead: for a readahead page, we hold it's covering lock to
 	 * prevent it from being canceled during recovery.
 	 *
 	 * \see osc_lock::ols_pageref
 	 * \see osc_page_addref_lock(), osc_page_putref_lock().
 	 */
 	struct cl_lock       *ops_lock;
 };

 extern struct kmem_cache *osc_lock_kmem;
 extern struct kmem_cache *osc_object_kmem;
 extern struct kmem_cache *osc_thread_kmem;
 extern struct kmem_cache *osc_session_kmem;
 extern struct kmem_cache *osc_req_kmem;
 extern struct kmem_cache *osc_extent_kmem;

 extern struct lu_device_type osc_device_type;
 extern struct lu_context_key osc_key;
 extern struct lu_context_key osc_session_key;

 #define OSC_FLAGS (ASYNC_URGENT|ASYNC_READY)

 int osc_lock_init(const struct lu_env *env,
 		  struct cl_object *obj, struct cl_lock *lock,
 		  const struct cl_io *io);
 int osc_io_init  (const struct lu_env *env,
 		  struct cl_object *obj, struct cl_io *io);
 int osc_req_init (const struct lu_env *env, struct cl_device *dev,
 		  struct cl_req *req);
 struct lu_object *osc_object_alloc(const struct lu_env *env,
 				   const struct lu_object_header *hdr,
 				   struct lu_device *dev);
 int osc_page_init(const struct lu_env *env, struct cl_object *obj,
 		  struct cl_page *page, struct page *vmpage);

 void osc_index2policy  (ldlm_policy_data_t *policy, const struct cl_object *obj,
 			pgoff_t start, pgoff_t end);
 int  osc_lvb_print     (const struct lu_env *env, void *cookie,
 			lu_printer_t p, const struct ost_lvb *lvb);

 void osc_page_submit(const struct lu_env *env, struct osc_page *opg,
 		     enum cl_req_type crt, int brw_flags);
 int osc_cancel_async_page(const struct lu_env *env, struct osc_page *ops);
 int osc_set_async_flags(struct osc_object *obj, struct osc_page *opg,
 			u32 async_flags);
 int osc_prep_async_page(struct osc_object *osc, struct osc_page *ops,
 			struct page *page, loff_t offset);
 int osc_queue_async_io(const struct lu_env *env, struct cl_io *io,
 		       struct osc_page *ops);
 int osc_teardown_async_page(const struct lu_env *env, struct osc_object *obj,
 			    struct osc_page *ops);
 int osc_flush_async_page(const struct lu_env *env, struct cl_io *io,
 			 struct osc_page *ops);
 int osc_queue_sync_pages(const struct lu_env *env, struct osc_object *obj,
 			 struct list_head *list, int cmd, int brw_flags);
 int osc_cache_truncate_start(const struct lu_env *env, struct osc_io *oio,
 			     struct osc_object *obj, __u64 size);
 void osc_cache_truncate_end(const struct lu_env *env, struct osc_io *oio,
 			    struct osc_object *obj);
 int osc_cache_writeback_range(const struct lu_env *env, struct osc_object *obj,
 			      pgoff_t start, pgoff_t end, int hp, int discard);
 int osc_cache_wait_range(const struct lu_env *env, struct osc_object *obj,
 			 pgoff_t start, pgoff_t end);
 void osc_io_unplug(const struct lu_env *env, struct client_obd *cli,
 		   struct osc_object *osc, pdl_policy_t pol);

 void osc_object_set_contended  (struct osc_object *obj);
 void osc_object_clear_contended(struct osc_object *obj);
 int  osc_object_is_contended   (struct osc_object *obj);

 int  osc_lock_is_lockless      (const struct osc_lock *olck);

 /*****************************************************************************
  *
  * Accessors.
  *
  */

 static inline struct osc_thread_info *osc_env_info(const struct lu_env *env)
 {
 	struct osc_thread_info *info;

 	info = lu_context_key_get(&env->le_ctx, &osc_key);
 	LASSERT(info != NULL);
 	return info;
 }

 static inline struct osc_session *osc_env_session(const struct lu_env *env)
 {
 	struct osc_session *ses;

 	ses = lu_context_key_get(env->le_ses, &osc_session_key);
 	LASSERT(ses != NULL);
 	return ses;
 }

 static inline struct osc_io *osc_env_io(const struct lu_env *env)
 {
 	return &osc_env_session(env)->os_io;
 }

 static inline int osc_is_object(const struct lu_object *obj)
 {
 	return obj->lo_dev->ld_type == &osc_device_type;
 }

 static inline struct osc_device *lu2osc_dev(const struct lu_device *d)
 {
 	LINVRNT(d->ld_type == &osc_device_type);
 	return container_of0(d, struct osc_device, od_cl.cd_lu_dev);
 }

 static inline struct obd_export *osc_export(const struct osc_object *obj)
 {
 	return lu2osc_dev(obj->oo_cl.co_lu.lo_dev)->od_exp;
 }

 static inline struct client_obd *osc_cli(const struct osc_object *obj)
 {
 	return &osc_export(obj)->exp_obd->u.cli;
 }

 static inline struct osc_object *cl2osc(const struct cl_object *obj)
 {
 	LINVRNT(osc_is_object(&obj->co_lu));
 	return container_of0(obj, struct osc_object, oo_cl);
 }

 static inline struct cl_object *osc2cl(const struct osc_object *obj)
 {
 	return (struct cl_object *)&obj->oo_cl;
 }

 static inline ldlm_mode_t osc_cl_lock2ldlm(enum cl_lock_mode mode)
 {
 	LASSERT(mode == CLM_READ || mode == CLM_WRITE || mode == CLM_GROUP);
 	if (mode == CLM_READ)
 		return LCK_PR;
 	else if (mode == CLM_WRITE)
 		return LCK_PW;
 	else
 		return LCK_GROUP;
 }

 static inline enum cl_lock_mode osc_ldlm2cl_lock(ldlm_mode_t mode)
 {
 	LASSERT(mode == LCK_PR || mode == LCK_PW || mode == LCK_GROUP);
 	if (mode == LCK_PR)
 		return CLM_READ;
 	else if (mode == LCK_PW)
 		return CLM_WRITE;
 	else
 		return CLM_GROUP;
 }

 static inline struct osc_page *cl2osc_page(const struct cl_page_slice *slice)
 {
 	LINVRNT(osc_is_object(&slice->cpl_obj->co_lu));
 	return container_of0(slice, struct osc_page, ops_cl);
 }

 static inline struct osc_page *oap2osc(struct osc_async_page *oap)
 {
 	return container_of0(oap, struct osc_page, ops_oap);
 }

 static inline struct cl_page *oap2cl_page(struct osc_async_page *oap)
 {
 	return oap2osc(oap)->ops_cl.cpl_page;
 }

 static inline struct osc_page *oap2osc_page(struct osc_async_page *oap)
 {
 	return (struct osc_page *)container_of(oap, struct osc_page, ops_oap);
 }

 static inline struct osc_lock *cl2osc_lock(const struct cl_lock_slice *slice)
 {
 	LINVRNT(osc_is_object(&slice->cls_obj->co_lu));
 	return container_of0(slice, struct osc_lock, ols_cl);
 }

 static inline struct osc_lock *osc_lock_at(const struct cl_lock *lock)
 {
 	return cl2osc_lock(cl_lock_at(lock, &osc_device_type));
 }

 static inline int osc_io_srvlock(struct osc_io *oio)
 {
 	return (oio->oi_lockless && !oio->oi_cl.cis_io->ci_no_srvlock);
 }

 enum osc_extent_state {
 	OES_INV       = 0, /** extent is just initialized or destroyed */
 	OES_ACTIVE    = 1, /** process is using this extent */
 	OES_CACHE     = 2, /** extent is ready for IO */
 	OES_LOCKING   = 3, /** locking page to prepare IO */
 	OES_LOCK_DONE = 4, /** locking finished, ready to send */
 	OES_RPC       = 5, /** in RPC */
 	OES_TRUNC     = 6, /** being truncated */
 	OES_STATE_MAX
 };

 /**
  * osc_extent data to manage dirty pages.
  * osc_extent has the following attributes:
  * 1. all pages in the same must be in one RPC in write back;
  * 2. # of pages must be less than max_pages_per_rpc - implied by 1;
  * 3. must be covered by only 1 osc_lock;
  * 4. exclusive. It's impossible to have overlapped osc_extent.
  *
  * The lifetime of an extent is from when the 1st page is dirtied to when
  * all pages inside it are written out.
  *
  * LOCKING ORDER
  * =============
  * page lock -> client_obd_list_lock -> object lock(osc_object::oo_lock)
  */
 struct osc_extent {
 	/** red-black tree node */
 	struct rb_node     oe_node;
 	/** osc_object of this extent */
 	struct osc_object *oe_obj;
 	/** refcount, removed from red-black tree if reaches zero. */
 	atomic_t       oe_refc;
 	/** busy if non-zero */
 	atomic_t       oe_users;
 	/** link list of osc_object's oo_{hp|urgent|locking}_exts. */
 	struct list_head	 oe_link;
 	/** state of this extent */
 	unsigned int       oe_state;
 	/** flags for this extent. */
 	unsigned int       oe_intree:1,
 	/** 0 is write, 1 is read */
 			   oe_rw:1,
 			   oe_srvlock:1,
 			   oe_memalloc:1,
 	/** an ACTIVE extent is going to be truncated, so when this extent
 	 * is released, it will turn into TRUNC state instead of CACHE. */
 			   oe_trunc_pending:1,
 	/** this extent should be written asap and someone may wait for the
 	 * write to finish. This bit is usually set along with urgent if
 	 * the extent was CACHE state.
 	 * fsync_wait extent can't be merged because new extent region may
 	 * exceed fsync range. */
 			   oe_fsync_wait:1,
 	/** covering lock is being canceled */
 			   oe_hp:1,
 	/** this extent should be written back asap. set if one of pages is
 	 * called by page WB daemon, or sync write or reading requests. */
 			   oe_urgent:1;
 	/** how many grants allocated for this extent.
 	 *  Grant allocated for this extent. There is no grant allocated
 	 *  for reading extents and sync write extents. */
 	unsigned int       oe_grants;
 	/** # of dirty pages in this extent */
 	unsigned int       oe_nr_pages;
 	/** list of pending oap pages. Pages in this list are NOT sorted. */
 	struct list_head	 oe_pages;
 	/** Since an extent has to be written out in atomic, this is used to
 	 * remember the next page need to be locked to write this extent out.
 	 * Not used right now.
 	 */
 	struct osc_page   *oe_next_page;
 	/** start and end index of this extent, include start and end
 	 * themselves. Page offset here is the page index of osc_pages.
 	 * oe_start is used as keyword for red-black tree. */
 	pgoff_t	    oe_start;
 	pgoff_t	    oe_end;
 	/** maximum ending index of this extent, this is limited by
 	 * max_pages_per_rpc, lock extent and chunk size. */
 	pgoff_t	    oe_max_end;
 	/** waitqueue - for those who want to be notified if this extent's
 	 * state has changed. */
 	wait_queue_head_t	oe_waitq;
 	/** lock covering this extent */
 	struct cl_lock    *oe_osclock;
 	/** terminator of this extent. Must be true if this extent is in IO. */
 	struct task_struct	*oe_owner;
 	/** return value of writeback. If somebody is waiting for this extent,
 	 * this value can be known by outside world. */
 	int		oe_rc;
 	/** max pages per rpc when this extent was created */
 	unsigned int       oe_mppr;
 };

 int osc_extent_finish(const struct lu_env *env, struct osc_extent *ext,
 		      int sent, int rc);
 void osc_extent_release(const struct lu_env *env, struct osc_extent *ext);

 /** @} osc */

 #endif /* OSC_CL_INTERNAL_H */
	/*
	* GPL HEADER START
	*
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 only,
	* as published by the Free Software Foundation.
	*
	* This program is distributed in the hope that it will be useful, but
	* WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* General Public License version 2 for more details (a copy is included
	* in the LICENSE file that accompanied this code).
	*
	* You should have received a copy of the GNU General Public License
	* version 2 along with this program; If not, see
	* http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
	*
	* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
	* CA 95054 USA or visit www.sun.com if you need additional information or
	* have any questions.
	*
	* GPL HEADER END
	*/
	/*
	* Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
	* Use is subject to license terms.
	*
	* Copyright (c) 2012, Intel Corporation.
	*/
	/*
	* This file is part of Lustre, http://www.lustre.org/
	* Lustre is a trademark of Sun Microsystems, Inc.
	*/
	/*
	* This file is part of Lustre, http://www.lustre.org/
	* Lustre is a trademark of Sun Microsystems, Inc.
	*
	* Internal interfaces of OSC layer.
	*
	* Author: Nikita Danilov <nikita.danilov@sun.com>
	* Author: Jinshan Xiong <jinshan.xiong@whamcloud.com>
	*/

	#ifndef OSC_CL_INTERNAL_H
	#define OSC_CL_INTERNAL_H

	#include "../../include/linux/libcfs/libcfs.h"

	#include "../include/obd.h"
	/* osc_build_res_name() */
	#include "../include/cl_object.h"
	#include "../include/lclient.h"
	#include "osc_internal.h"

	/** \defgroup osc osc
	* @{
	*/

	struct osc_extent;

	/**
	* State maintained by osc layer for each IO context.
	*/
	struct osc_io {
	/** super class */
	struct cl_io_slice oi_cl;
	/** true if this io is lockless. */
	int oi_lockless;
	/** active extents, we know how many bytes is going to be written,
	* so having an active extent will prevent it from being fragmented */
	struct osc_extent *oi_active;
	/** partially truncated extent, we need to hold this extent to prevent
	* page writeback from happening. */
	struct osc_extent *oi_trunc;

	struct obd_info oi_info;
	struct obdo oi_oa;
	struct osc_async_cbargs {
	bool opc_rpc_sent;
	int opc_rc;
	struct completion opc_sync;
	} oi_cbarg;
	};

	/**
	* State of transfer for osc.
	*/
	struct osc_req {
	struct cl_req_slice or_cl;
	};

	/**
	* State maintained by osc layer for the duration of a system call.
	*/
	struct osc_session {
	struct osc_io os_io;
	};

	#define OTI_PVEC_SIZE 64
	struct osc_thread_info {
	struct ldlm_res_id oti_resname;
	ldlm_policy_data_t oti_policy;
	struct cl_lock_descr oti_descr;
	struct cl_attr oti_attr;
	struct lustre_handle oti_handle;
	struct cl_page_list oti_plist;
	struct cl_io oti_io;
	struct cl_page *oti_pvec[OTI_PVEC_SIZE];
	};

	struct osc_object {
	struct cl_object oo_cl;
	struct lov_oinfo *oo_oinfo;
	/**
	* True if locking against this stripe got -EUSERS.
	*/
	int oo_contended;
	unsigned long oo_contention_time;
	/**
	* List of pages in transfer.
	*/
	struct list_head oo_inflight[CRT_NR];
	/**
	* Lock, protecting ccc_object::cob_inflight, because a seat-belt is
	* locked during take-off and landing.
	*/
	spinlock_t oo_seatbelt;

	/**
	* used by the osc to keep track of what objects to build into rpcs.
	* Protected by client_obd->cli_loi_list_lock.
	*/
	struct list_head oo_ready_item;
	struct list_head oo_hp_ready_item;
	struct list_head oo_write_item;
	struct list_head oo_read_item;

	/**
	* extent is a red black tree to manage (async) dirty pages.
	*/
	struct rb_root oo_root;
	/**
	* Manage write(dirty) extents.
	*/
	struct list_head oo_hp_exts; /* list of hp extents */
	struct list_head oo_urgent_exts; /* list of writeback extents */
	struct list_head oo_rpc_exts;

	struct list_head oo_reading_exts;

	atomic_t oo_nr_reads;
	atomic_t oo_nr_writes;

	/** Protect extent tree. Will be used to protect
	* oo_{read\|write}_pages soon. */
	spinlock_t oo_lock;
	};

	static inline void osc_object_lock(struct osc_object *obj)
	{
	spin_lock(&obj->oo_lock);
	}

	static inline int osc_object_trylock(struct osc_object *obj)
	{
	return spin_trylock(&obj->oo_lock);
	}

	static inline void osc_object_unlock(struct osc_object *obj)
	{
	spin_unlock(&obj->oo_lock);
	}

	static inline int osc_object_is_locked(struct osc_object *obj)
	{
	#if defined(CONFIG_SMP) \|\| defined(CONFIG_DEBUG_SPINLOCK)
	return spin_is_locked(&obj->oo_lock);
	#else
	/*
	* It is not perfect to return true all the time.
	* But since this function is only used for assertion
	* and checking, it seems OK.
	*/
	return 1;
	#endif
	}

	/*
	* Lock "micro-states" for osc layer.
	*/
	enum osc_lock_state {
	OLS_NEW,
	OLS_ENQUEUED,
	OLS_UPCALL_RECEIVED,
	OLS_GRANTED,
	OLS_RELEASED,
	OLS_BLOCKED,
	OLS_CANCELLED
	};

	/**
	* osc-private state of cl_lock.
	*
	* Interaction with DLM.
	*
	* CLIO enqueues all DLM locks through ptlrpcd (that is, in "async" mode).
	*
	* Once receive upcall is invoked, osc_lock remembers a handle of DLM lock in
	* osc_lock::ols_handle and a pointer to that lock in osc_lock::ols_lock.
	*
	* This pointer is protected through a reference, acquired by
	* osc_lock_upcall0(). Also, an additional reference is acquired by
	* ldlm_lock_addref() call protecting the lock from cancellation, until
	* osc_lock_unuse() releases it.
	*
	* Below is a description of how lock references are acquired and released
	* inside of DLM.
	*
	* - When new lock is created and enqueued to the server (ldlm_cli_enqueue())
	* - ldlm_lock_create()
	* - ldlm_lock_new(): initializes a lock with 2 references. One for
	* the caller (released when reply from the server is received, or on
	* error), and another for the hash table.
	* - ldlm_lock_addref_internal(): protects the lock from cancellation.
	*
	* - When reply is received from the server (osc_enqueue_interpret())
	* - ldlm_cli_enqueue_fini()
	* - LDLM_LOCK_PUT(): releases caller reference acquired by
	* ldlm_lock_new().
	* - if (rc != 0)
	* ldlm_lock_decref(): error case: matches ldlm_cli_enqueue().
	* - ldlm_lock_decref(): for async locks, matches ldlm_cli_enqueue().
	*
	* - When lock is being cancelled (ldlm_lock_cancel())
	* - ldlm_lock_destroy()
	* - LDLM_LOCK_PUT(): releases hash-table reference acquired by
	* ldlm_lock_new().
	*
	* osc_lock is detached from ldlm_lock by osc_lock_detach() that is called
	* either when lock is cancelled (osc_lock_blocking()), or when locks is
	* deleted without cancellation (e.g., from cl_locks_prune()). In the latter
	* case ldlm lock remains in memory, and can be re-attached to osc_lock in the
	* future.
	*/
	struct osc_lock {
	struct cl_lock_slice ols_cl;
	/** underlying DLM lock */
	struct ldlm_lock *ols_lock;
	/** lock value block */
	struct ost_lvb ols_lvb;
	/** DLM flags with which osc_lock::ols_lock was enqueued */
	__u64 ols_flags;
	/** osc_lock::ols_lock handle */
	struct lustre_handle ols_handle;
	struct ldlm_enqueue_info ols_einfo;
	enum osc_lock_state ols_state;

	/**
	* How many pages are using this lock for io, currently only used by
	* read-ahead. If non-zero, the underlying dlm lock won't be cancelled
	* during recovery to avoid deadlock. see bz16774.
	*
	* \see osc_page::ops_lock
	* \see osc_page_addref_lock(), osc_page_putref_lock()
	*/
	atomic_t ols_pageref;

	/**
	* true, if ldlm_lock_addref() was called against
	* osc_lock::ols_lock. This is used for sanity checking.
	*
	* \see osc_lock::ols_has_ref
	*/
	unsigned ols_hold :1,
	/**
	* this is much like osc_lock::ols_hold, except that this bit is
	* cleared _after_ reference in released in osc_lock_unuse(). This
	* fine distinction is needed because:
	*
	* - if ldlm lock still has a reference, osc_ast_data_get() needs
	* to return associated cl_lock (so that a flag is needed that is
	* cleared after ldlm_lock_decref() returned), and
	*
	* - ldlm_lock_decref() can invoke blocking ast (for a
	* LDLM_FL_CBPENDING lock), and osc_lock functions like
	* osc_lock_cancel() called from there need to know whether to
	* release lock reference (so that a flag is needed that is
	* cleared before ldlm_lock_decref() is called).
	*/
	ols_has_ref:1,
	/**
	* inherit the lockless attribute from top level cl_io.
	* If true, osc_lock_enqueue is able to tolerate the -EUSERS error.
	*/
	ols_locklessable:1,
	/**
	* set by osc_lock_use() to wait until blocking AST enters into
	* osc_ldlm_blocking_ast0(), so that cl_lock mutex can be used for
	* further synchronization.
	*/
	ols_ast_wait:1,
	/**
	* If the data of this lock has been flushed to server side.
	*/
	ols_flush:1,
	/**
	* if set, the osc_lock is a glimpse lock. For glimpse locks, we treat
	* the EVAVAIL error as tolerable, this will make upper logic happy
	* to wait all glimpse locks to each OSTs to be completed.
	* Glimpse lock converts to normal lock if the server lock is
	* granted.
	* Glimpse lock should be destroyed immediately after use.
	*/
	ols_glimpse:1,
	/**
	* For async glimpse lock.
	*/
	ols_agl:1;
	/**
	* IO that owns this lock. This field is used for a dead-lock
	* avoidance by osc_lock_enqueue_wait().
	*
	* XXX: unfortunately, the owner of a osc_lock is not unique,
	* the lock may have multiple users, if the lock is granted and
	* then matched.
	*/
	struct osc_io *ols_owner;
	};


	/**
	* Page state private for osc layer.
	*/
	struct osc_page {
	struct cl_page_slice ops_cl;
	/**
	* Page queues used by osc to detect when RPC can be formed.
	*/
	struct osc_async_page ops_oap;
	/**
	* An offset within page from which next transfer starts. This is used
	* by cl_page_clip() to submit partial page transfers.
	*/
	int ops_from;
	/**
	* An offset within page at which next transfer ends.
	*
	* \see osc_page::ops_from.
	*/
	int ops_to;
	/**
	* Boolean, true iff page is under transfer. Used for sanity checking.
	*/
	unsigned ops_transfer_pinned:1,
	/**
	* True for a `temporary page' created by read-ahead code, probably
	* outside of any DLM lock.
	*/
	ops_temp:1,
	/**
	* in LRU?
	*/
	ops_in_lru:1,
	/**
	* Set if the page must be transferred with OBD_BRW_SRVLOCK.
	*/
	ops_srvlock:1;
	union {
	/**
	* lru page list. ops_inflight and ops_lru are exclusive so
	* that they can share the same data.
	*/
	struct list_head ops_lru;
	/**
	* Linkage into a per-osc_object list of pages in flight. For
	* debugging.
	*/
	struct list_head ops_inflight;
	};
	/**
	* Thread that submitted this page for transfer. For debugging.
	*/
	struct task_struct *ops_submitter;
	/**
	* Submit time - the time when the page is starting RPC. For debugging.
	*/
	unsigned long ops_submit_time;

	/**
	* A lock of which we hold a reference covers this page. Only used by
	* read-ahead: for a readahead page, we hold it's covering lock to
	* prevent it from being canceled during recovery.
	*
	* \see osc_lock::ols_pageref
	* \see osc_page_addref_lock(), osc_page_putref_lock().
	*/
	struct cl_lock *ops_lock;
	};

	extern struct kmem_cache *osc_lock_kmem;
	extern struct kmem_cache *osc_object_kmem;
	extern struct kmem_cache *osc_thread_kmem;
	extern struct kmem_cache *osc_session_kmem;
	extern struct kmem_cache *osc_req_kmem;
	extern struct kmem_cache *osc_extent_kmem;

	extern struct lu_device_type osc_device_type;
	extern struct lu_context_key osc_key;
	extern struct lu_context_key osc_session_key;

	#define OSC_FLAGS (ASYNC_URGENT\|ASYNC_READY)

	int osc_lock_init(const struct lu_env *env,
	struct cl_object obj, struct cl_lock lock,
	const struct cl_io *io);
	int osc_io_init (const struct lu_env *env,
	struct cl_object obj, struct cl_io io);
	int osc_req_init (const struct lu_env env, struct cl_device dev,
	struct cl_req *req);
	struct lu_object osc_object_alloc(const struct lu_env env,
	const struct lu_object_header *hdr,
	struct lu_device *dev);
	int osc_page_init(const struct lu_env env, struct cl_object obj,
	struct cl_page page, struct page vmpage);

	void osc_index2policy (ldlm_policy_data_t policy, const struct cl_object obj,
	pgoff_t start, pgoff_t end);
	int osc_lvb_print (const struct lu_env env, void cookie,
	lu_printer_t p, const struct ost_lvb *lvb);

	void osc_page_submit(const struct lu_env env, struct osc_page opg,
	enum cl_req_type crt, int brw_flags);
	int osc_cancel_async_page(const struct lu_env env, struct osc_page ops);
	int osc_set_async_flags(struct osc_object obj, struct osc_page opg,
	u32 async_flags);
	int osc_prep_async_page(struct osc_object osc, struct osc_page ops,
	struct page *page, loff_t offset);
	int osc_queue_async_io(const struct lu_env env, struct cl_io io,
	struct osc_page *ops);
	int osc_teardown_async_page(const struct lu_env env, struct osc_object obj,
	struct osc_page *ops);
	int osc_flush_async_page(const struct lu_env env, struct cl_io io,
	struct osc_page *ops);
	int osc_queue_sync_pages(const struct lu_env env, struct osc_object obj,
	struct list_head *list, int cmd, int brw_flags);
	int osc_cache_truncate_start(const struct lu_env env, struct osc_io oio,
	struct osc_object *obj, __u64 size);
	void osc_cache_truncate_end(const struct lu_env env, struct osc_io oio,
	struct osc_object *obj);
	int osc_cache_writeback_range(const struct lu_env env, struct osc_object obj,
	pgoff_t start, pgoff_t end, int hp, int discard);
	int osc_cache_wait_range(const struct lu_env env, struct osc_object obj,
	pgoff_t start, pgoff_t end);
	void osc_io_unplug(const struct lu_env env, struct client_obd cli,
	struct osc_object *osc, pdl_policy_t pol);

	void osc_object_set_contended (struct osc_object *obj);
	void osc_object_clear_contended(struct osc_object *obj);
	int osc_object_is_contended (struct osc_object *obj);

	int osc_lock_is_lockless (const struct osc_lock *olck);

	/*****************************************************************************
	*
	* Accessors.
	*
	*/

	static inline struct osc_thread_info osc_env_info(const struct lu_env env)
	{
	struct osc_thread_info *info;

	info = lu_context_key_get(&env->le_ctx, &osc_key);
	LASSERT(info != NULL);
	return info;
	}

	static inline struct osc_session osc_env_session(const struct lu_env env)
	{
	struct osc_session *ses;

	ses = lu_context_key_get(env->le_ses, &osc_session_key);
	LASSERT(ses != NULL);
	return ses;
	}

	static inline struct osc_io osc_env_io(const struct lu_env env)
	{
	return &osc_env_session(env)->os_io;
	}

	static inline int osc_is_object(const struct lu_object *obj)
	{
	return obj->lo_dev->ld_type == &osc_device_type;
	}

	static inline struct osc_device lu2osc_dev(const struct lu_device d)
	{
	LINVRNT(d->ld_type == &osc_device_type);
	return container_of0(d, struct osc_device, od_cl.cd_lu_dev);
	}

	static inline struct obd_export osc_export(const struct osc_object obj)
	{
	return lu2osc_dev(obj->oo_cl.co_lu.lo_dev)->od_exp;
	}

	static inline struct client_obd osc_cli(const struct osc_object obj)
	{
	return &osc_export(obj)->exp_obd->u.cli;
	}

	static inline struct osc_object cl2osc(const struct cl_object obj)
	{
	LINVRNT(osc_is_object(&obj->co_lu));
	return container_of0(obj, struct osc_object, oo_cl);
	}

	static inline struct cl_object osc2cl(const struct osc_object obj)
	{
	return (struct cl_object *)&obj->oo_cl;
	}

	static inline ldlm_mode_t osc_cl_lock2ldlm(enum cl_lock_mode mode)
	{
	LASSERT(mode == CLM_READ \|\| mode == CLM_WRITE \|\| mode == CLM_GROUP);
	if (mode == CLM_READ)
	return LCK_PR;
	else if (mode == CLM_WRITE)
	return LCK_PW;
	else
	return LCK_GROUP;
	}

	static inline enum cl_lock_mode osc_ldlm2cl_lock(ldlm_mode_t mode)
	{
	LASSERT(mode == LCK_PR \|\| mode == LCK_PW \|\| mode == LCK_GROUP);
	if (mode == LCK_PR)
	return CLM_READ;
	else if (mode == LCK_PW)
	return CLM_WRITE;
	else
	return CLM_GROUP;
	}

	static inline struct osc_page cl2osc_page(const struct cl_page_slice slice)
	{
	LINVRNT(osc_is_object(&slice->cpl_obj->co_lu));
	return container_of0(slice, struct osc_page, ops_cl);
	}

	static inline struct osc_page oap2osc(struct osc_async_page oap)
	{
	return container_of0(oap, struct osc_page, ops_oap);
	}

	static inline struct cl_page oap2cl_page(struct osc_async_page oap)
	{
	return oap2osc(oap)->ops_cl.cpl_page;
	}

	static inline struct osc_page oap2osc_page(struct osc_async_page oap)
	{
	return (struct osc_page *)container_of(oap, struct osc_page, ops_oap);
	}

	static inline struct osc_lock cl2osc_lock(const struct cl_lock_slice slice)
	{
	LINVRNT(osc_is_object(&slice->cls_obj->co_lu));
	return container_of0(slice, struct osc_lock, ols_cl);
	}

	static inline struct osc_lock osc_lock_at(const struct cl_lock lock)
	{
	return cl2osc_lock(cl_lock_at(lock, &osc_device_type));
	}

	static inline int osc_io_srvlock(struct osc_io *oio)
	{
	return (oio->oi_lockless && !oio->oi_cl.cis_io->ci_no_srvlock);
	}

	enum osc_extent_state {
	OES_INV = 0, /** extent is just initialized or destroyed */
	OES_ACTIVE = 1, /** process is using this extent */
	OES_CACHE = 2, /** extent is ready for IO */
	OES_LOCKING = 3, /** locking page to prepare IO */
	OES_LOCK_DONE = 4, /** locking finished, ready to send */
	OES_RPC = 5, /** in RPC */
	OES_TRUNC = 6, /** being truncated */
	OES_STATE_MAX
	};

	/**
	* osc_extent data to manage dirty pages.
	* osc_extent has the following attributes:
	* 1. all pages in the same must be in one RPC in write back;
	* 2. # of pages must be less than max_pages_per_rpc - implied by 1;
	* 3. must be covered by only 1 osc_lock;
	* 4. exclusive. It's impossible to have overlapped osc_extent.
	*
	* The lifetime of an extent is from when the 1st page is dirtied to when
	* all pages inside it are written out.
	*
	* LOCKING ORDER
	* =============
	* page lock -> client_obd_list_lock -> object lock(osc_object::oo_lock)
	*/
	struct osc_extent {
	/** red-black tree node */
	struct rb_node oe_node;
	/** osc_object of this extent */
	struct osc_object *oe_obj;
	/** refcount, removed from red-black tree if reaches zero. */
	atomic_t oe_refc;
	/** busy if non-zero */
	atomic_t oe_users;
	/** link list of osc_object's oo_{hp\|urgent\|locking}_exts. */
	struct list_head oe_link;
	/** state of this extent */
	unsigned int oe_state;
	/** flags for this extent. */
	unsigned int oe_intree:1,
	/** 0 is write, 1 is read */
	oe_rw:1,
	oe_srvlock:1,
	oe_memalloc:1,
	/** an ACTIVE extent is going to be truncated, so when this extent
	* is released, it will turn into TRUNC state instead of CACHE. */
	oe_trunc_pending:1,
	/** this extent should be written asap and someone may wait for the
	* write to finish. This bit is usually set along with urgent if
	* the extent was CACHE state.
	* fsync_wait extent can't be merged because new extent region may
	* exceed fsync range. */
	oe_fsync_wait:1,
	/** covering lock is being canceled */
	oe_hp:1,
	/** this extent should be written back asap. set if one of pages is
	* called by page WB daemon, or sync write or reading requests. */
	oe_urgent:1;
	/** how many grants allocated for this extent.
	* Grant allocated for this extent. There is no grant allocated
	* for reading extents and sync write extents. */
	unsigned int oe_grants;
	/** # of dirty pages in this extent */
	unsigned int oe_nr_pages;
	/** list of pending oap pages. Pages in this list are NOT sorted. */
	struct list_head oe_pages;
	/** Since an extent has to be written out in atomic, this is used to
	* remember the next page need to be locked to write this extent out.
	* Not used right now.
	*/
	struct osc_page *oe_next_page;
	/** start and end index of this extent, include start and end
	* themselves. Page offset here is the page index of osc_pages.
	* oe_start is used as keyword for red-black tree. */
	pgoff_t oe_start;
	pgoff_t oe_end;
	/** maximum ending index of this extent, this is limited by
	* max_pages_per_rpc, lock extent and chunk size. */
	pgoff_t oe_max_end;
	/** waitqueue - for those who want to be notified if this extent's
	* state has changed. */
	wait_queue_head_t oe_waitq;
	/** lock covering this extent */
	struct cl_lock *oe_osclock;
	/** terminator of this extent. Must be true if this extent is in IO. */
	struct task_struct *oe_owner;
	/** return value of writeback. If somebody is waiting for this extent,
	* this value can be known by outside world. */
	int oe_rc;
	/** max pages per rpc when this extent was created */
	unsigned int oe_mppr;
	};

	int osc_extent_finish(const struct lu_env env, struct osc_extent ext,
	int sent, int rc);
	void osc_extent_release(const struct lu_env env, struct osc_extent ext);

	/** @} osc */

	#endif /* OSC_CL_INTERNAL_H */