[fs/lustre-release.git] / lustre / include / lustre_osc.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.gnu.org/licenses/gpl-2.0.html
 *
 * GPL HEADER END
 */
/*
 * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright (c) 2012, 2017, Intel Corporation.
 */
/*
 * This file is part of Lustre, http://www.lustre.org/
 * Lustre is a trademark of Sun Microsystems, Inc.
 */
/*
 * lustre/include/lustre_osc.h
 *
 * OSC layer structures and methods common for both OSC and MDC.
 *
 * This file contains OSC interfaces used by OSC and MDC. Most of them
 * were just moved from lustre/osc/osc_cl_internal.h for Data-on-MDT
 * purposes.
 *
 *   Author: Nikita Danilov <nikita.danilov@sun.com>
 *   Author: Jinshan Xiong <jinshan.xiong@whamcloud.com>
 *   Author: Mikhail Pershin <mike.pershin@intel.com>
 */

#ifndef LUSTRE_OSC_H
#define LUSTRE_OSC_H

#include <libcfs/libcfs.h>
#include <obd.h>
#include <cl_object.h>

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

struct osc_quota_info {
        /** linkage for quota hash table */
        struct hlist_node oqi_hash;
        __u32             oqi_id;
};

enum async_flags {
        ASYNC_READY = 0x1, /* ap_make_ready will not be called before this
                              page is added to an rpc */
        ASYNC_URGENT = 0x2, /* page must be put into an RPC before return */
        ASYNC_COUNT_STABLE = 0x4, /* ap_refresh_count will not be called
                                     to give the caller a chance to update
                                     or cancel the size of the io */
        ASYNC_HP = 0x10,
};

struct osc_async_page {
        int                     oap_magic;
        unsigned short          oap_cmd;
        unsigned short          oap_interrupted:1;

        struct list_head        oap_pending_item;
        struct list_head        oap_rpc_item;

        loff_t                  oap_obj_off;
        unsigned                oap_page_off;
        enum async_flags        oap_async_flags;

        struct brw_page         oap_brw_page;

        struct ptlrpc_request   *oap_request;
        struct client_obd       *oap_cli;
        struct osc_object       *oap_obj;

        spinlock_t               oap_lock;
};

#define oap_page        oap_brw_page.pg
#define oap_count       oap_brw_page.count
#define oap_brw_flags   oap_brw_page.flag

static inline struct osc_async_page *brw_page2oap(struct brw_page *pga)
{
        return container_of(pga, struct osc_async_page, oap_brw_page);
}

struct osc_cache_waiter {
        struct list_head        ocw_entry;
        wait_queue_head_t       ocw_waitq;
        struct osc_async_page   *ocw_oap;
        int                     ocw_grant;
        int                     ocw_rc;
};

struct osc_device {
        struct cl_device        od_cl;
        struct obd_export       *od_exp;

        /* Write stats is actually protected by client_obd's lock. */
        struct osc_stats {
                uint64_t        os_lockless_writes;    /* by bytes */
                uint64_t        os_lockless_reads;     /* by bytes */
                uint64_t        os_lockless_truncates; /* by times */
        } od_stats;

        /* configuration item(s) */
        time64_t                od_contention_time;
        int                     od_lockless_truncate;
};

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. */
        unsigned int       oi_lockless:1,
        /** true if this io is counted as active IO */
                           oi_is_active:1;
        /** how many LRU pages are reserved for this IO */
        unsigned long      oi_lru_reserved;

        /** 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;
        /** write osc_lock for this IO, used by osc_extent_find(). */
        struct osc_lock   *oi_write_osclock;
        struct obdo        oi_oa;
        struct osc_async_cbargs {
                bool              opc_rpc_sent;
                int               opc_rc;
                struct completion opc_sync;
        } oi_cbarg;
};

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

#define OTI_PVEC_SIZE 256
struct osc_thread_info {
        struct ldlm_res_id      oti_resname;
        union ldlm_policy_data  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 pagevec          oti_pagevec;
        void                    *oti_pvec[OTI_PVEC_SIZE];
        /**
         * Fields used by cl_lock_discard_pages().
         */
        pgoff_t                 oti_next_index;
        pgoff_t                 oti_fn_index; /* first non-overlapped index */
        struct cl_sync_io       oti_anchor;
        struct cl_req_attr      oti_req_attr;
        struct lu_buf           oti_ladvise_buf;
};

static inline __u64 osc_enq2ldlm_flags(__u32 enqflags)
{
        __u64 result = 0;

        CDEBUG(D_DLMTRACE, "flags: %x\n", enqflags);

        LASSERT((enqflags & ~CEF_MASK) == 0);

        if (enqflags & CEF_NONBLOCK)
                result |= LDLM_FL_BLOCK_NOWAIT;
        if (enqflags & CEF_GLIMPSE)
                result |= LDLM_FL_HAS_INTENT;
        if (enqflags & CEF_DISCARD_DATA)
                result |= LDLM_FL_AST_DISCARD_DATA;
        if (enqflags & CEF_PEEK)
                result |= LDLM_FL_TEST_LOCK;
        if (enqflags & CEF_LOCK_MATCH)
                result |= LDLM_FL_MATCH_LOCK;
        if (enqflags & CEF_LOCK_NO_EXPAND)
                result |= LDLM_FL_NO_EXPANSION;
        if (enqflags & CEF_SPECULATIVE)
                result |= LDLM_FL_SPECULATIVE;
        return result;
}

typedef int (*osc_enqueue_upcall_f)(void *cookie, struct lustre_handle *lockh,
                                    int rc);

struct osc_enqueue_args {
        struct obd_export       *oa_exp;
        enum ldlm_type          oa_type;
        enum ldlm_mode          oa_mode;
        __u64                   *oa_flags;
        osc_enqueue_upcall_f    oa_upcall;
        void                    *oa_cookie;
        struct ost_lvb          *oa_lvb;
        struct lustre_handle    oa_lockh;
        bool                    oa_speculative;
};

/**
 * Bit flags for osc_dlm_lock_at_pageoff().
 */
enum osc_dap_flags {
        /**
         * Just check if the desired lock exists, it won't hold reference
         * count on lock.
         */
        OSC_DAP_FL_TEST_LOCK = 1 << 0,
        /**
         * Return the lock even if it is being canceled.
         */
        OSC_DAP_FL_CANCELING = 1 << 1
};

/*
 * The set of operations which are different for MDC and OSC objects
 */
struct osc_object_operations {
        void (*oto_build_res_name)(struct osc_object *osc,
                                   struct ldlm_res_id *resname);
        struct ldlm_lock* (*oto_dlmlock_at_pgoff)(const struct lu_env *env,
                                                struct osc_object *obj,
                                                pgoff_t index,
                                                enum osc_dap_flags dap_flags);
};

struct osc_object {
        struct cl_object        oo_cl;
        struct lov_oinfo        *oo_oinfo;
        /**
         * True if locking against this stripe got -EUSERS.
         */
        int                     oo_contended;
        ktime_t                 oo_contention_time;
#ifdef CONFIG_LUSTRE_DEBUG_EXPENSIVE_CHECK
        /**
         * IO context used for invariant checks in osc_lock_has_pages().
         */
        struct cl_io            oo_debug_io;
        /** Serialization object for osc_object::oo_debug_io. */
        struct mutex            oo_debug_mutex;
#endif
        /**
         * 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_full_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;

        /**
         * Radix tree for caching pages
         */
        spinlock_t              oo_tree_lock;
        struct radix_tree_root  oo_tree;
        unsigned long           oo_npages;

        /* Protect osc_lock this osc_object has */
        struct list_head        oo_ol_list;
        spinlock_t              oo_ol_spin;

        /** number of active IOs of this object */
        atomic_t                oo_nr_ios;
        wait_queue_head_t       oo_io_waitq;

        const struct osc_object_operations *oo_obj_ops;
        bool                    oo_initialized;
};

static inline void osc_build_res_name(struct osc_object *osc,
                                      struct ldlm_res_id *resname)
{
        return osc->oo_obj_ops->oto_build_res_name(osc, resname);
}

static inline struct ldlm_lock *osc_dlmlock_at_pgoff(const struct lu_env *env,
                                                    struct osc_object *obj,
                                                    pgoff_t index,
                                                    enum osc_dap_flags flags)
{
        return obj->oo_obj_ops->oto_dlmlock_at_pgoff(env, obj, index, flags);
}

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
}

static inline void osc_object_set_contended(struct osc_object *obj)
{
        obj->oo_contention_time = ktime_get();
        /* mb(); */
        obj->oo_contended = 1;
}

static inline void osc_object_clear_contended(struct osc_object *obj)
{
        obj->oo_contended = 0;
}

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

/**
 * osc-private state of cl_lock.
 *
 * Interaction with DLM.
 *
 * 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_dlmlock.
 *
 * 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;
        /** Internal lock to protect states, etc. */
        spinlock_t              ols_lock;
        /** Owner sleeps on this channel for state change */
        struct cl_sync_io       *ols_owner;
        /** waiting list for this lock to be cancelled */
        struct list_head        ols_waiting_list;
        /** wait entry of ols_waiting_list */
        struct list_head        ols_wait_entry;
        /** list entry for osc_object::oo_ol_list */
        struct list_head        ols_nextlock_oscobj;

        /** underlying DLM lock */
        struct ldlm_lock        *ols_dlmlock;
        /** 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;
        /** lock value block */
        struct ost_lvb          ols_lvb;
        /** Lockless operations to be used by lockless lock */
        const struct cl_lock_operations *ols_lockless_ops;
        /**
         * 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,
        /**
         * if set, the osc_lock is a glimpse lock. For glimpse locks, we treat
         * the EVAVAIL error as torerable, 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,
        /**
         * for speculative locks - asynchronous glimpse locks and ladvise
         * lockahead manual lock requests
         *
         * Used to tell osc layer to not wait for the ldlm reply from the
         * server, so the osc lock will be short lived - It only exists to
         * create the ldlm request and is not updated on request completion.
         */
                                ols_speculative:1;
};

static inline int osc_lock_is_lockless(const struct osc_lock *ols)
{
        return (ols->ols_cl.cls_ops == ols->ols_lockless_ops);
}

/**
 * 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,
        /**
         * in LRU?
         */
                                ops_in_lru:1,
        /**
         * Set if the page must be transferred with OBD_BRW_SRVLOCK.
         */
                                ops_srvlock:1,
        /**
         * If the page is in osc_object::oo_tree.
         */
                                ops_intree:1;
        /**
         * lru page list. See osc_lru_{del|use}() in osc_page.c for usage.
         */
        struct list_head        ops_lru;
        /**
         * Submit time - the time when the page is starting RPC. For debugging.
         */
        ktime_t                 ops_submit_time;
};

struct osc_brw_async_args {
        struct obdo             *aa_oa;
        int                      aa_requested_nob;
        int                      aa_nio_count;
        u32                      aa_page_count;
        int                      aa_resends;
        struct brw_page         **aa_ppga;
        struct client_obd       *aa_cli;
        struct list_head         aa_oaps;
        struct list_head         aa_exts;
};

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_extent_kmem;
extern struct kmem_cache *osc_quota_kmem;
extern struct kmem_cache *osc_obdo_kmem;

extern struct lu_context_key osc_key;
extern struct lu_context_key osc_session_key;

#define OSC_FLAGS (ASYNC_URGENT|ASYNC_READY)

/* osc_page.c */
int osc_page_init(const struct lu_env *env, struct cl_object *obj,
                  struct cl_page *page, pgoff_t ind);
void osc_index2policy(union ldlm_policy_data *policy, const struct cl_object *obj,
                      pgoff_t start, pgoff_t end);
void osc_lru_add_batch(struct client_obd *cli, struct list_head *list);
void osc_page_submit(const struct lu_env *env, struct osc_page *opg,
                     enum cl_req_type crt, int brw_flags);
int lru_queue_work(const struct lu_env *env, void *data);
long osc_lru_shrink(const struct lu_env *env, struct client_obd *cli,
                    long target, bool force);

/* osc_cache.c */
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_page_cache_add(const struct lu_env *env,
                       const struct cl_page_slice *slice, struct cl_io *io);
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, const struct cl_io *io,
                         struct osc_object *obj, struct list_head *list,
                         int brw_flags);
int osc_cache_truncate_start(const struct lu_env *env, struct osc_object *obj,
                             __u64 size, struct osc_extent **extp);
void osc_cache_truncate_end(const struct lu_env *env, struct osc_extent *ext);
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);
int osc_io_unplug0(const struct lu_env *env, struct client_obd *cli,
                   struct osc_object *osc, int async);
void osc_wake_cache_waiters(struct client_obd *cli);

static inline int osc_io_unplug_async(const struct lu_env *env,
                                      struct client_obd *cli,
                                      struct osc_object *osc)
{
        return osc_io_unplug0(env, cli, osc, 1);
}

static inline void osc_io_unplug(const struct lu_env *env,
                                 struct client_obd *cli,
                                 struct osc_object *osc)
{
        (void)osc_io_unplug0(env, cli, osc, 0);
}

typedef int (*osc_page_gang_cbt)(const struct lu_env *, struct cl_io *,
                                 struct osc_page *, void *);
int osc_page_gang_lookup(const struct lu_env *env, struct cl_io *io,
                        struct osc_object *osc, pgoff_t start, pgoff_t end,
                        osc_page_gang_cbt cb, void *cbdata);
int osc_discard_cb(const struct lu_env *env, struct cl_io *io,
                   struct osc_page *ops, void *cbdata);

/* osc_dev.c */
int osc_device_init(const struct lu_env *env, struct lu_device *d,
                    const char *name, struct lu_device *next);
struct lu_device *osc_device_fini(const struct lu_env *env,
                                  struct lu_device *d);
struct lu_device *osc_device_free(const struct lu_env *env,
                                  struct lu_device *d);

/* osc_object.c */
int osc_object_init(const struct lu_env *env, struct lu_object *obj,
                    const struct lu_object_conf *conf);
void osc_object_free(const struct lu_env *env, struct lu_object *obj);
int osc_lvb_print(const struct lu_env *env, void *cookie,
                  lu_printer_t p, const struct ost_lvb *lvb);
int osc_object_print(const struct lu_env *env, void *cookie,
                     lu_printer_t p, const struct lu_object *obj);
int osc_attr_get(const struct lu_env *env, struct cl_object *obj,
                 struct cl_attr *attr);
int osc_attr_update(const struct lu_env *env, struct cl_object *obj,
                    const struct cl_attr *attr, unsigned valid);
int osc_object_glimpse(const struct lu_env *env, const struct cl_object *obj,
                       struct ost_lvb *lvb);
int osc_object_invalidate(const struct lu_env *env, struct osc_object *osc);
int osc_object_is_contended(struct osc_object *obj);
int osc_object_find_cbdata(const struct lu_env *env, struct cl_object *obj,
                           ldlm_iterator_t iter, void *data);
int osc_object_prune(const struct lu_env *env, struct cl_object *obj);

/* osc_request.c */
void osc_init_grant(struct client_obd *cli, struct obd_connect_data *ocd);
int osc_setup_common(struct obd_device *obd, struct lustre_cfg *lcfg);
int osc_precleanup_common(struct obd_device *obd);
int osc_cleanup_common(struct obd_device *obd);
int osc_set_info_async(const struct lu_env *env, struct obd_export *exp,
                       u32 keylen, void *key, u32 vallen, void *val,
                       struct ptlrpc_request_set *set);
int osc_ldlm_resource_invalidate(struct cfs_hash *hs, struct cfs_hash_bd *bd,
                                 struct hlist_node *hnode, void *arg);
int osc_reconnect(const struct lu_env *env, struct obd_export *exp,
                  struct obd_device *obd, struct obd_uuid *cluuid,
                  struct obd_connect_data *data, void *localdata);
int osc_disconnect(struct obd_export *exp);
int osc_punch_send(struct obd_export *exp, struct obdo *oa,
                   obd_enqueue_update_f upcall, void *cookie);

/* osc_io.c */
int osc_io_submit(const struct lu_env *env, const struct cl_io_slice *ios,
                  enum cl_req_type crt, struct cl_2queue *queue);
int osc_io_commit_async(const struct lu_env *env,
                        const struct cl_io_slice *ios,
                        struct cl_page_list *qin, int from, int to,
                        cl_commit_cbt cb);
int osc_io_iter_init(const struct lu_env *env, const struct cl_io_slice *ios);
void osc_io_iter_fini(const struct lu_env *env,
                      const struct cl_io_slice *ios);
int osc_io_write_iter_init(const struct lu_env *env,
                           const struct cl_io_slice *ios);
void osc_io_write_iter_fini(const struct lu_env *env,
                            const struct cl_io_slice *ios);
int osc_io_fault_start(const struct lu_env *env, const struct cl_io_slice *ios);
void osc_io_setattr_end(const struct lu_env *env,
                        const struct cl_io_slice *slice);
int osc_io_read_start(const struct lu_env *env,
                      const struct cl_io_slice *slice);
int osc_io_write_start(const struct lu_env *env,
                       const struct cl_io_slice *slice);
void osc_io_end(const struct lu_env *env, const struct cl_io_slice *slice);
int osc_fsync_ost(const struct lu_env *env, struct osc_object *obj,
                  struct cl_fsync_io *fio);
void osc_io_fsync_end(const struct lu_env *env,
                      const struct cl_io_slice *slice);
void osc_read_ahead_release(const struct lu_env *env, void *cbdata);

/* osc_lock.c */
void osc_lock_to_lockless(const struct lu_env *env, struct osc_lock *ols,
                          int force);
void osc_lock_wake_waiters(const struct lu_env *env, struct osc_object *osc,
                           struct osc_lock *oscl);
int osc_lock_enqueue_wait(const struct lu_env *env, struct osc_object *obj,
                          struct osc_lock *oscl);
void osc_lock_set_writer(const struct lu_env *env, const struct cl_io *io,
                         struct cl_object *obj, struct osc_lock *oscl);
int osc_lock_print(const struct lu_env *env, void *cookie,
                   lu_printer_t p, const struct cl_lock_slice *slice);
void osc_lock_cancel(const struct lu_env *env,
                     const struct cl_lock_slice *slice);
void osc_lock_fini(const struct lu_env *env, struct cl_lock_slice *slice);
int osc_ldlm_glimpse_ast(struct ldlm_lock *dlmlock, void *data);
unsigned long osc_ldlm_weigh_ast(struct ldlm_lock *dlmlock);

/*****************************************************************************
 *
 * Accessors and type conversions.
 *
 */
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 struct osc_device *lu2osc_dev(const struct lu_device *d)
{
        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)
{
        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 struct osc_device *obd2osc_dev(const struct obd_device *d)
{
        return container_of0(d->obd_lu_dev, struct osc_device,
                             od_cl.cd_lu_dev);
}

static inline struct lu_device *osc2lu_dev(struct osc_device *osc)
{
        return &osc->od_cl.cd_lu_dev;
}

static inline struct lu_object *osc2lu(struct osc_object *osc)
{
        return &osc->oo_cl.co_lu;
}

static inline struct osc_object *lu2osc(const struct lu_object *obj)
{
        return container_of0(obj, struct osc_object, oo_cl.co_lu);
}

static inline struct osc_io *cl2osc_io(const struct lu_env *env,
                                       const struct cl_io_slice *slice)
{
        struct osc_io *oio = container_of0(slice, struct osc_io, oi_cl);

        LINVRNT(oio == osc_env_io(env));
        return oio;
}

static inline enum ldlm_mode 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;
        if (mode == CLM_WRITE)
                return LCK_PW;
        return LCK_GROUP;
}

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

static inline struct osc_page *cl2osc_page(const struct cl_page_slice *slice)
{
        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 pgoff_t osc_index(struct osc_page *opg)
{
        return opg->ops_cl.cpl_index;
}

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_page *
osc_cl_page_osc(struct cl_page *page, struct osc_object *osc)
{
        const struct cl_page_slice *slice;

        LASSERT(osc != NULL);
        slice = cl_object_page_slice(&osc->oo_cl, page);
        return cl2osc_page(slice);
}

static inline struct osc_lock *cl2osc_lock(const struct cl_lock_slice *slice)
{
        return container_of0(slice, struct osc_lock, ols_cl);
}

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 */
        enum osc_extent_state   oe_state;
        /** flags for this extent. */
        unsigned int            oe_intree:1,
        /** 0 is write, 1 is read */
                                oe_rw:1,
        /** sync extent, queued by osc_queue_sync_pages() */
                                oe_sync:1,
        /** set if this extent has partial, sync pages.
         * Extents with partial page(s) can't merge with others in RPC */
                                oe_no_merge: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,
        /** Non-delay RPC should be used for this extent. */
                                oe_ndelay: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 ldlm_lock        *oe_dlmlock;
        /** 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;
        /** FLR: layout version when this osc_extent is publised */
        __u32                   oe_layout_version;
};

/** @} osc */

#endif /* LUSTRE_OSC_H */