LU-4257 llite: fast read implementation

[fs/lustre-release.git] / lustre / llite / llite_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) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright (c) 2011, 2015, Intel Corporation.
 */
/*
 * This file is part of Lustre, http://www.lustre.org/
 * Lustre is a trademark of Sun Microsystems, Inc.
 */

#ifndef LLITE_INTERNAL_H
#define LLITE_INTERNAL_H
#include <lustre_debug.h>
#include <lustre_ver.h>
#include <lustre_disk.h>  /* for s2sbi */
#include <lustre_eacl.h>
#include <lustre_linkea.h>

/* for struct cl_lock_descr and struct cl_io */
#include <cl_object.h>
#include <lustre_lmv.h>
#include <lustre_mdc.h>
#include <lustre_intent.h>
#include <linux/compat.h>
#include <linux/aio.h>

#include "vvp_internal.h"
#include "range_lock.h"

#ifndef FMODE_EXEC
#define FMODE_EXEC 0
#endif

#ifndef VM_FAULT_RETRY
#define VM_FAULT_RETRY 0
#endif

/* Kernel 3.1 kills LOOKUP_CONTINUE, LOOKUP_PARENT is equivalent to it.
 * seem kernel commit 49084c3bb2055c401f3493c13edae14d49128ca0 */
#ifndef LOOKUP_CONTINUE
#define LOOKUP_CONTINUE LOOKUP_PARENT
#endif

/** Only used on client-side for indicating the tail of dir hash/offset. */
#define LL_DIR_END_OFF          0x7fffffffffffffffULL
#define LL_DIR_END_OFF_32BIT    0x7fffffffUL

/* 4UL * 1024 * 1024 */
#define LL_MAX_BLKSIZE_BITS 22

#define LL_IT2STR(it) ((it) ? ldlm_it2str((it)->it_op) : "0")
#define LUSTRE_FPRIVATE(file) ((file)->private_data)

struct ll_dentry_data {
        struct lookup_intent            *lld_it;
        unsigned int                    lld_sa_generation;
        unsigned int                    lld_invalid:1;
        struct rcu_head                 lld_rcu_head;
};

#define ll_d2d(de) ((struct ll_dentry_data*)((de)->d_fsdata))

#define LLI_INODE_MAGIC                 0x111d0de5
#define LLI_INODE_DEAD                  0xdeadd00d

/* remote client permission cache */
#define REMOTE_PERM_HASHSIZE 16

struct ll_getname_data {
#ifdef HAVE_DIR_CONTEXT
        struct dir_context      ctx;
#endif
        char            *lgd_name;      /* points to a buffer with NAME_MAX+1 size */
        struct lu_fid   lgd_fid;        /* target fid we are looking for */
        int             lgd_found;      /* inode matched? */
};

/* llite setxid/access permission for user on remote client */
struct ll_remote_perm {
        struct hlist_node       lrp_list;
        uid_t                   lrp_uid;
        gid_t                   lrp_gid;
        uid_t                   lrp_fsuid;
        gid_t                   lrp_fsgid;
        int                     lrp_access_perm; /* MAY_READ/WRITE/EXEC, this
                                                    is access permission with
                                                    lrp_fsuid/lrp_fsgid. */
};

struct ll_grouplock {
        struct lu_env   *lg_env;
        struct cl_io    *lg_io;
        struct cl_lock  *lg_lock;
        unsigned long    lg_gid;
};

struct ll_inode_info {
        __u32                           lli_inode_magic;
        spinlock_t                      lli_lock;

        volatile unsigned long          lli_flags;
        struct posix_acl                *lli_posix_acl;

        struct hlist_head               *lli_remote_perms;
        struct mutex                    lli_rmtperm_mutex;

        /* identifying fields for both metadata and data stacks. */
        struct lu_fid                   lli_fid;
        /* master inode fid for stripe directory */
        struct lu_fid                   lli_pfid;

        /* open count currently used by capability only, indicate whether
         * capability needs renewal */
        atomic_t                        lli_open_count;
        cfs_time_t                      lli_rmtperm_time;

        /* We need all three because every inode may be opened in different
         * modes */
        struct obd_client_handle       *lli_mds_read_och;
        struct obd_client_handle       *lli_mds_write_och;
        struct obd_client_handle       *lli_mds_exec_och;
        __u64                           lli_open_fd_read_count;
        __u64                           lli_open_fd_write_count;
        __u64                           lli_open_fd_exec_count;
        /* Protects access to och pointers and their usage counters */
        struct mutex                    lli_och_mutex;

        struct inode                    lli_vfs_inode;

        /* the most recent timestamps obtained from mds */
        s64                             lli_atime;
        s64                             lli_mtime;
        s64                             lli_ctime;
        spinlock_t                      lli_agl_lock;

        /* Try to make the d::member and f::member are aligned. Before using
         * these members, make clear whether it is directory or not. */
        union {
                /* for directory */
                struct {
                        /* serialize normal readdir and statahead-readdir. */
                        struct mutex                    lli_readdir_mutex;

                        /* metadata statahead */
                        /* since parent-child threads can share the same @file
                         * struct, "opendir_key" is the token when dir close for
                         * case of parent exit before child -- it is me should
                         * cleanup the dir readahead. */
                        void                           *lli_opendir_key;
                        struct ll_statahead_info       *lli_sai;
                        /* protect statahead stuff. */
                        spinlock_t                      lli_sa_lock;
                        /* "opendir_pid" is the token when lookup/revalid
                         * -- I am the owner of dir statahead. */
                        pid_t                           lli_opendir_pid;
                        /* stat will try to access statahead entries or start
                         * statahead if this flag is set, and this flag will be
                         * set upon dir open, and cleared when dir is closed,
                         * statahead hit ratio is too low, or start statahead
                         * thread failed. */
                        unsigned int                    lli_sa_enabled:1;
                        /* generation for statahead */
                        unsigned int                    lli_sa_generation;
                        /* directory stripe information */
                        struct lmv_stripe_md            *lli_lsm_md;
                        /* default directory stripe offset.  This is extracted
                         * from the "dmv" xattr in order to decide which MDT to
                         * create a subdirectory on.  The MDS itself fetches
                         * "dmv" and gets the rest of the default layout itself
                         * (count, hash, etc). */
                        __u32                           lli_def_stripe_offset;
                };

                /* for non-directory */
                struct {
                        struct mutex                    lli_size_mutex;
                        char                           *lli_symlink_name;
                        /*
                         * struct rw_semaphore {
                         *    signed long       count;     // align d.d_def_acl
                         *    spinlock_t        wait_lock; // align d.d_sa_lock
                         *    struct list_head wait_list;
                         * }
                         */
                        struct rw_semaphore             lli_trunc_sem;
                        struct range_lock_tree          lli_write_tree;

                        struct rw_semaphore             lli_glimpse_sem;
                        cfs_time_t                      lli_glimpse_time;
                        struct list_head                lli_agl_list;
                        __u64                           lli_agl_index;

                        /* for writepage() only to communicate to fsync */
                        int                             lli_async_rc;

                        /*
                         * whenever a process try to read/write the file, the
                         * jobid of the process will be saved here, and it'll
                         * be packed into the write PRC when flush later.
                         *
                         * so the read/write statistics for jobid will not be
                         * accurate if the file is shared by different jobs.
                         */
                        char                    lli_jobid[LUSTRE_JOBID_SIZE];
                };
        };

        /* XXX: For following frequent used members, although they maybe special
         *      used for non-directory object, it is some time-wasting to check
         *      whether the object is directory or not before using them. On the
         *      other hand, currently, sizeof(f) > sizeof(d), it cannot reduce
         *      the "ll_inode_info" size even if moving those members into u.f.
         *      So keep them out side.
         *
         *      In the future, if more members are added only for directory,
         *      some of the following members can be moved into u.f.
         */
        struct cl_object                *lli_clob;

        /* mutex to request for layout lock exclusively. */
        struct mutex                    lli_layout_mutex;
        /* Layout version, protected by lli_layout_lock */
        __u32                           lli_layout_gen;
        spinlock_t                      lli_layout_lock;

        struct rw_semaphore             lli_xattrs_list_rwsem;
        struct mutex                    lli_xattrs_enq_lock;
        struct list_head                lli_xattrs; /* ll_xattr_entry->xe_list */
};

static inline __u32 ll_layout_version_get(struct ll_inode_info *lli)
{
        __u32 gen;

        spin_lock(&lli->lli_layout_lock);
        gen = lli->lli_layout_gen;
        spin_unlock(&lli->lli_layout_lock);

        return gen;
}

static inline void ll_layout_version_set(struct ll_inode_info *lli, __u32 gen)
{
        spin_lock(&lli->lli_layout_lock);
        lli->lli_layout_gen = gen;
        spin_unlock(&lli->lli_layout_lock);
}

enum ll_file_flags {
        /* File data is modified. */
        LLIF_DATA_MODIFIED      = 0,
        /* File is being restored */
        LLIF_FILE_RESTORING     = 1,
        /* Xattr cache is attached to the file */
        LLIF_XATTR_CACHE        = 2,
};

static inline void ll_file_set_flag(struct ll_inode_info *lli,
                                    enum ll_file_flags flag)
{
        set_bit(flag, &lli->lli_flags);
}

static inline void ll_file_clear_flag(struct ll_inode_info *lli,
                                      enum ll_file_flags flag)
{
        clear_bit(flag, &lli->lli_flags);
}

static inline bool ll_file_test_flag(struct ll_inode_info *lli,
                                     enum ll_file_flags flag)
{
        return test_bit(flag, &lli->lli_flags);
}

static inline bool ll_file_test_and_clear_flag(struct ll_inode_info *lli,
                                               enum ll_file_flags flag)
{
        return test_and_clear_bit(flag, &lli->lli_flags);
}

int ll_xattr_cache_destroy(struct inode *inode);

int ll_xattr_cache_get(struct inode *inode,
                        const char *name,
                        char *buffer,
                        size_t size,
                        __u64 valid);

int ll_init_security(struct dentry *dentry,
                            struct inode *inode,
                            struct inode *dir);

/*
 * Locking to guarantee consistency of non-atomic updates to long long i_size,
 * consistency between file size and KMS.
 *
 * Implemented by ->lli_size_mutex and ->lsm_lock, nested in that order.
 */

void ll_inode_size_lock(struct inode *inode);
void ll_inode_size_unlock(struct inode *inode);

// FIXME: replace the name of this with LL_I to conform to kernel stuff
// static inline struct ll_inode_info *LL_I(struct inode *inode)
static inline struct ll_inode_info *ll_i2info(struct inode *inode)
{
        return container_of(inode, struct ll_inode_info, lli_vfs_inode);
}

/* default to about 64M of readahead on a given system. */
#define SBI_DEFAULT_READAHEAD_MAX       (64UL << (20 - PAGE_CACHE_SHIFT))

/* default to read-ahead full files smaller than 2MB on the second read */
#define SBI_DEFAULT_READAHEAD_WHOLE_MAX (2UL << (20 - PAGE_CACHE_SHIFT))

enum ra_stat {
        RA_STAT_HIT = 0,
        RA_STAT_MISS,
        RA_STAT_DISTANT_READPAGE,
        RA_STAT_MISS_IN_WINDOW,
        RA_STAT_FAILED_GRAB_PAGE,
        RA_STAT_FAILED_MATCH,
        RA_STAT_DISCARDED,
        RA_STAT_ZERO_LEN,
        RA_STAT_ZERO_WINDOW,
        RA_STAT_EOF,
        RA_STAT_MAX_IN_FLIGHT,
        RA_STAT_WRONG_GRAB_PAGE,
        RA_STAT_FAILED_REACH_END,
        _NR_RA_STAT,
};

struct ll_ra_info {
        atomic_t        ra_cur_pages;
        unsigned long   ra_max_pages;
        unsigned long   ra_max_pages_per_file;
        unsigned long   ra_max_read_ahead_whole_pages;
};

/* ra_io_arg will be filled in the beginning of ll_readahead with
 * ras_lock, then the following ll_read_ahead_pages will read RA
 * pages according to this arg, all the items in this structure are
 * counted by page index.
 */
struct ra_io_arg {
        unsigned long ria_start;  /* start offset of read-ahead*/
        unsigned long ria_end;    /* end offset of read-ahead*/
        unsigned long ria_reserved; /* reserved pages for read-ahead */
        unsigned long ria_end_min;  /* minimum end to cover current read */
        bool          ria_eof;    /* reach end of file */
        /* If stride read pattern is detected, ria_stoff means where
         * stride read is started. Note: for normal read-ahead, the
         * value here is meaningless, and also it will not be accessed*/
        pgoff_t ria_stoff;
        /* ria_length and ria_pages are the length and pages length in the
         * stride I/O mode. And they will also be used to check whether
         * it is stride I/O read-ahead in the read-ahead pages*/
        unsigned long ria_length;
        unsigned long ria_pages;
};

/* LL_HIST_MAX=32 causes an overflow */
#define LL_HIST_MAX 28
#define LL_HIST_START 12 /* buckets start at 2^12 = 4k */
#define LL_PROCESS_HIST_MAX 10
struct per_process_info {
        pid_t pid;
        struct obd_histogram pp_r_hist;
        struct obd_histogram pp_w_hist;
};

/* pp_extents[LL_PROCESS_HIST_MAX] will hold the combined process info */
struct ll_rw_extents_info {
        struct per_process_info pp_extents[LL_PROCESS_HIST_MAX + 1];
};

#define LL_OFFSET_HIST_MAX 100
struct ll_rw_process_info {
        pid_t                     rw_pid;
        int                       rw_op;
        loff_t                    rw_range_start;
        loff_t                    rw_range_end;
        loff_t                    rw_last_file_pos;
        loff_t                    rw_offset;
        size_t                    rw_smallest_extent;
        size_t                    rw_largest_extent;
        struct ll_file_data      *rw_last_file;
};

enum stats_track_type {
        STATS_TRACK_ALL = 0,  /* track all processes */
        STATS_TRACK_PID,      /* track process with this pid */
        STATS_TRACK_PPID,     /* track processes with this ppid */
        STATS_TRACK_GID,      /* track processes with this gid */
        STATS_TRACK_LAST,
};

/* flags for sbi->ll_flags */
#define LL_SBI_NOLCK             0x01 /* DLM locking disabled (directio-only) */
#define LL_SBI_CHECKSUM          0x02 /* checksum each page as it's written */
#define LL_SBI_FLOCK             0x04
#define LL_SBI_USER_XATTR        0x08 /* support user xattr */
#define LL_SBI_ACL               0x10 /* support ACL */
#define LL_SBI_RMT_CLIENT        0x40 /* remote client */
#define LL_SBI_MDS_CAPA          0x80 /* support mds capa, obsolete */
#define LL_SBI_OSS_CAPA         0x100 /* support oss capa, obsolete */
#define LL_SBI_LOCALFLOCK       0x200 /* Local flocks support by kernel */
#define LL_SBI_LRU_RESIZE       0x400 /* lru resize support */
#define LL_SBI_LAZYSTATFS       0x800 /* lazystatfs mount option */
/*      LL_SBI_SOM_PREVIEW     0x1000    SOM preview mount option, obsolete */
#define LL_SBI_32BIT_API       0x2000 /* generate 32 bit inodes. */
#define LL_SBI_64BIT_HASH      0x4000 /* support 64-bits dir hash/offset */
#define LL_SBI_AGL_ENABLED     0x8000 /* enable agl */
#define LL_SBI_VERBOSE        0x10000 /* verbose mount/umount */
#define LL_SBI_LAYOUT_LOCK    0x20000 /* layout lock support */
#define LL_SBI_USER_FID2PATH  0x40000 /* allow fid2path by unprivileged users */
#define LL_SBI_XATTR_CACHE    0x80000 /* support for xattr cache */
#define LL_SBI_NOROOTSQUASH  0x100000 /* do not apply root squash */
#define LL_SBI_ALWAYS_PING   0x200000 /* always ping even if server
                                       * suppress_pings */
#define LL_SBI_FAST_READ     0x400000 /* fast read support */

#define LL_SBI_FLAGS {  \
        "nolck",        \
        "checksum",     \
        "flock",        \
        "user_xattr",   \
        "acl",          \
        "???",          \
        "rmt_client",   \
        "mds_capa",     \
        "oss_capa",     \
        "flock",        \
        "lru_resize",   \
        "lazy_statfs",  \
        "som",          \
        "32bit_api",    \
        "64bit_hash",   \
        "agl",          \
        "verbose",      \
        "layout",       \
        "user_fid2path",\
        "xattr_cache",  \
        "norootsquash", \
        "always_ping",  \
        "fast_read",    \
}

#define RCE_HASHES      32

struct rmtacl_ctl_entry {
        struct list_head       rce_list;
        pid_t            rce_key; /* hash key */
        int              rce_ops; /* acl operation type */
};

struct rmtacl_ctl_table {
        spinlock_t      rct_lock;
        struct list_head        rct_entries[RCE_HASHES];
};

#define EE_HASHES       32

struct eacl_entry {
        struct list_head            ee_list;
        pid_t                 ee_key; /* hash key */
        struct lu_fid         ee_fid;
        int                   ee_type; /* ACL type for ACCESS or DEFAULT */
        ext_acl_xattr_header *ee_acl;
};

struct eacl_table {
        spinlock_t      et_lock;
        struct list_head        et_entries[EE_HASHES];
};


/* This is embedded into llite super-blocks to keep track of connect
 * flags (capabilities) supported by all imports given mount is
 * connected to. */
struct lustre_client_ocd {
        /* This is conjunction of connect_flags across all imports
         * (LOVs) this mount is connected to. This field is updated by
         * cl_ocd_update() under ->lco_lock. */
        __u64                    lco_flags;
        struct mutex             lco_lock;
        struct obd_export       *lco_md_exp;
        struct obd_export       *lco_dt_exp;
};

struct ll_sb_info {
        /* this protects pglist and ra_info.  It isn't safe to
         * grab from interrupt contexts */
        spinlock_t                ll_lock;
        spinlock_t                ll_pp_extent_lock; /* pp_extent entry*/
        spinlock_t                ll_process_lock; /* ll_rw_process_info */
        struct obd_uuid           ll_sb_uuid;
        struct obd_export        *ll_md_exp;
        struct obd_export        *ll_dt_exp;
        struct proc_dir_entry*    ll_proc_root;
        struct lu_fid             ll_root_fid; /* root object fid */

        int                       ll_flags;
        unsigned int              ll_umounting:1,
                                  ll_xattr_cache_enabled:1,
                                  ll_client_common_fill_super_succeeded:1;

        /* per-conn chain of SBs */
        struct list_head                ll_conn_chain;
        struct lustre_client_ocd  ll_lco;

        /*please don't ask -p*/
        struct list_head        ll_orphan_dentry_list;

        struct lprocfs_stats     *ll_stats; /* lprocfs stats counter */

        /* Used to track "unstable" pages on a client, and maintain a
         * LRU list of clean pages. An "unstable" page is defined as
         * any page which is sent to a server as part of a bulk request,
         * but is uncommitted to stable storage. */
        struct cl_client_cache   *ll_cache;

        struct lprocfs_stats     *ll_ra_stats;

        struct ll_ra_info         ll_ra_info;
        unsigned int              ll_namelen;
        struct file_operations   *ll_fop;

        unsigned int              ll_md_brw_pages; /* readdir pages per RPC */

        struct lu_site           *ll_site;
        struct cl_device         *ll_cl;
        /* Statistics */
        struct ll_rw_extents_info ll_rw_extents_info;
        int                       ll_extent_process_count;
        struct ll_rw_process_info ll_rw_process_info[LL_PROCESS_HIST_MAX];
        unsigned int              ll_offset_process_count;
        struct ll_rw_process_info ll_rw_offset_info[LL_OFFSET_HIST_MAX];
        unsigned int              ll_rw_offset_entry_count;
        int                       ll_stats_track_id;
        enum stats_track_type     ll_stats_track_type;
        int                       ll_rw_stats_on;

        /* metadata stat-ahead */
        unsigned int              ll_sa_max;     /* max statahead RPCs */
        atomic_t                  ll_sa_total;   /* statahead thread started
                                                  * count */
        atomic_t                  ll_sa_wrong;   /* statahead thread stopped for
                                                  * low hit ratio */
        atomic_t                  ll_sa_running; /* running statahead thread
                                                  * count */
        atomic_t                  ll_agl_total;  /* AGL thread started count */

        dev_t                     ll_sdev_orig; /* save s_dev before assign for
                                                 * clustred nfs */
        struct rmtacl_ctl_table   ll_rct;
        struct eacl_table         ll_et;

        /* root squash */
        struct root_squash_info   ll_squash;
};

/*
 * per file-descriptor read-ahead data.
 */
struct ll_readahead_state {
        spinlock_t  ras_lock;
        /*
         * index of the last page that read(2) needed and that wasn't in the
         * cache. Used by ras_update() to detect seeks.
         *
         * XXX nikita: if access seeks into cached region, Lustre doesn't see
         * this.
         */
        unsigned long   ras_last_readpage;
        /*
         * number of pages read after last read-ahead window reset. As window
         * is reset on each seek, this is effectively a number of consecutive
         * accesses. Maybe ->ras_accessed_in_window is better name.
         *
         * XXX nikita: window is also reset (by ras_update()) when Lustre
         * believes that memory pressure evicts read-ahead pages. In that
         * case, it probably doesn't make sense to expand window to
         * PTLRPC_MAX_BRW_PAGES on the third access.
         */
        unsigned long   ras_consecutive_pages;
        /*
         * number of read requests after the last read-ahead window reset
         * As window is reset on each seek, this is effectively the number
         * on consecutive read request and is used to trigger read-ahead.
         */
        unsigned long   ras_consecutive_requests;
        /*
         * Parameters of current read-ahead window. Handled by
         * ras_update(). On the initial access to the file or after a seek,
         * window is reset to 0. After 3 consecutive accesses, window is
         * expanded to PTLRPC_MAX_BRW_PAGES. Afterwards, window is enlarged by
         * PTLRPC_MAX_BRW_PAGES chunks up to ->ra_max_pages.
         */
        unsigned long   ras_window_start, ras_window_len;
        /*
         * Optimal RPC size. It decides how many pages will be sent
         * for each read-ahead.
         */
        unsigned long   ras_rpc_size;
        /*
         * Where next read-ahead should start at. This lies within read-ahead
         * window. Read-ahead window is read in pieces rather than at once
         * because: 1. lustre limits total number of pages under read-ahead by
         * ->ra_max_pages (see ll_ra_count_get()), 2. client cannot read pages
         * not covered by DLM lock.
         */
        unsigned long   ras_next_readahead;
        /*
         * Total number of ll_file_read requests issued, reads originating
         * due to mmap are not counted in this total.  This value is used to
         * trigger full file read-ahead after multiple reads to a small file.
         */
        unsigned long   ras_requests;
        /*
         * Page index with respect to the current request, these value
         * will not be accurate when dealing with reads issued via mmap.
         */
        unsigned long   ras_request_index;
        /*
         * The following 3 items are used for detecting the stride I/O
         * mode.
         * In stride I/O mode,
         * ...............|-----data-----|****gap*****|--------|******|....
         *    offset      |-stride_pages-|-stride_gap-|
         * ras_stride_offset = offset;
         * ras_stride_length = stride_pages + stride_gap;
         * ras_stride_pages = stride_pages;
         * Note: all these three items are counted by pages.
         */
        unsigned long   ras_stride_length;
        unsigned long   ras_stride_pages;
        pgoff_t         ras_stride_offset;
        /*
         * number of consecutive stride request count, and it is similar as
         * ras_consecutive_requests, but used for stride I/O mode.
         * Note: only more than 2 consecutive stride request are detected,
         * stride read-ahead will be enable
         */
        unsigned long   ras_consecutive_stride_requests;
};

extern struct kmem_cache *ll_file_data_slab;
struct lustre_handle;
struct ll_file_data {
        struct ll_readahead_state fd_ras;
        struct ll_grouplock fd_grouplock;
        __u64 lfd_pos;
        __u32 fd_flags;
        fmode_t fd_omode;
        /* openhandle if lease exists for this file.
         * Borrow lli->lli_och_mutex to protect assignment */
        struct obd_client_handle *fd_lease_och;
        struct obd_client_handle *fd_och;
        struct file *fd_file;
        /* Indicate whether need to report failure when close.
         * true: failure is known, not report again.
         * false: unknown failure, should report. */
        bool fd_write_failed;
        rwlock_t fd_lock; /* protect lcc list */
        struct list_head fd_lccs; /* list of ll_cl_context */
};

extern spinlock_t inode_lock;

extern struct proc_dir_entry *proc_lustre_fs_root;

static inline struct inode *ll_info2i(struct ll_inode_info *lli)
{
        return &lli->lli_vfs_inode;
}

__u32 ll_i2suppgid(struct inode *i);
void ll_i2gids(__u32 *suppgids, struct inode *i1,struct inode *i2);

static inline int ll_need_32bit_api(struct ll_sb_info *sbi)
{
#if BITS_PER_LONG == 32
        return 1;
#elif defined(CONFIG_COMPAT)
        return unlikely(is_compat_task() || (sbi->ll_flags & LL_SBI_32BIT_API));
#else
        return unlikely(sbi->ll_flags & LL_SBI_32BIT_API);
#endif
}

static inline bool ll_sbi_has_fast_read(struct ll_sb_info *sbi)
{
        return !!(sbi->ll_flags & LL_SBI_FAST_READ);
}

void ll_ras_enter(struct file *f);

/* llite/lcommon_misc.c */
int cl_ocd_update(struct obd_device *host, struct obd_device *watched,
                  enum obd_notify_event ev, void *owner, void *data);
int cl_get_grouplock(struct cl_object *obj, unsigned long gid, int nonblock,
                     struct ll_grouplock *lg);
void cl_put_grouplock(struct ll_grouplock *lg);

/* llite/lproc_llite.c */
#ifdef CONFIG_PROC_FS
int lprocfs_register_mountpoint(struct proc_dir_entry *parent,
                                struct super_block *sb, char *osc, char *mdc);
void lprocfs_unregister_mountpoint(struct ll_sb_info *sbi);
void ll_stats_ops_tally(struct ll_sb_info *sbi, int op, int count);
extern struct lprocfs_vars lprocfs_llite_obd_vars[];
#else
static inline int lprocfs_register_mountpoint(struct proc_dir_entry *parent,
                        struct super_block *sb, char *osc, char *mdc){return 0;}
static inline void lprocfs_unregister_mountpoint(struct ll_sb_info *sbi) {}
static void ll_stats_ops_tally(struct ll_sb_info *sbi, int op, int count) {}
#endif

enum {
        LPROC_LL_DIRTY_HITS,
        LPROC_LL_DIRTY_MISSES,
        LPROC_LL_READ_BYTES,
        LPROC_LL_WRITE_BYTES,
        LPROC_LL_BRW_READ,
        LPROC_LL_BRW_WRITE,
        LPROC_LL_IOCTL,
        LPROC_LL_OPEN,
        LPROC_LL_RELEASE,
        LPROC_LL_MAP,
        LPROC_LL_FAULT,
        LPROC_LL_MKWRITE,
        LPROC_LL_LLSEEK,
        LPROC_LL_FSYNC,
        LPROC_LL_READDIR,
        LPROC_LL_SETATTR,
        LPROC_LL_TRUNC,
        LPROC_LL_FLOCK,
        LPROC_LL_GETATTR,
        LPROC_LL_CREATE,
        LPROC_LL_LINK,
        LPROC_LL_UNLINK,
        LPROC_LL_SYMLINK,
        LPROC_LL_MKDIR,
        LPROC_LL_RMDIR,
        LPROC_LL_MKNOD,
        LPROC_LL_RENAME,
        LPROC_LL_STAFS,
        LPROC_LL_ALLOC_INODE,
        LPROC_LL_SETXATTR,
        LPROC_LL_GETXATTR,
        LPROC_LL_GETXATTR_HITS,
        LPROC_LL_LISTXATTR,
        LPROC_LL_REMOVEXATTR,
        LPROC_LL_INODE_PERM,
        LPROC_LL_FILE_OPCODES
};

/* llite/dir.c */
struct ll_dir_chain {
};

static inline void ll_dir_chain_init(struct ll_dir_chain *chain)
{
}

static inline void ll_dir_chain_fini(struct ll_dir_chain *chain)
{
}

extern const struct file_operations ll_dir_operations;
extern const struct inode_operations ll_dir_inode_operations;
#ifdef HAVE_DIR_CONTEXT
int ll_dir_read(struct inode *inode, __u64 *pos, struct md_op_data *op_data,
                struct dir_context *ctx);
#else
int ll_dir_read(struct inode *inode, __u64 *pos, struct md_op_data *op_data,
                void *cookie, filldir_t filldir);
#endif
int ll_get_mdt_idx(struct inode *inode);
int ll_get_mdt_idx_by_fid(struct ll_sb_info *sbi, const struct lu_fid *fid);
struct page *ll_get_dir_page(struct inode *dir, struct md_op_data *op_data,
                             __u64 offset, struct ll_dir_chain *chain);
void ll_release_page(struct inode *inode, struct page *page, bool remove);

/* llite/namei.c */
extern const struct inode_operations ll_special_inode_operations;

struct inode *ll_iget(struct super_block *sb, ino_t hash,
                      struct lustre_md *lic);
int ll_test_inode_by_fid(struct inode *inode, void *opaque);
int ll_md_blocking_ast(struct ldlm_lock *, struct ldlm_lock_desc *,
                       void *data, int flag);
struct dentry *ll_splice_alias(struct inode *inode, struct dentry *de);
int ll_rmdir_entry(struct inode *dir, char *name, int namelen);
void ll_update_times(struct ptlrpc_request *request, struct inode *inode);

/* llite/rw.c */
int ll_writepage(struct page *page, struct writeback_control *wbc);
int ll_writepages(struct address_space *, struct writeback_control *wbc);
int ll_readpage(struct file *file, struct page *page);
void ll_readahead_init(struct inode *inode, struct ll_readahead_state *ras);
int vvp_io_write_commit(const struct lu_env *env, struct cl_io *io);

enum lcc_type;
void ll_cl_add(struct file *file, const struct lu_env *env, struct cl_io *io,
               enum lcc_type type);
void ll_cl_remove(struct file *file, const struct lu_env *env);
struct ll_cl_context *ll_cl_find(struct file *file);

extern const struct address_space_operations ll_aops;

/* llite/file.c */
extern struct file_operations ll_file_operations;
extern struct file_operations ll_file_operations_flock;
extern struct file_operations ll_file_operations_noflock;
extern struct inode_operations ll_file_inode_operations;
extern int ll_have_md_lock(struct inode *inode, __u64 *bits,
                           enum ldlm_mode l_req_mode);
extern enum ldlm_mode ll_take_md_lock(struct inode *inode, __u64 bits,
                                      struct lustre_handle *lockh, __u64 flags,
                                      enum ldlm_mode mode);

int ll_file_open(struct inode *inode, struct file *file);
int ll_file_release(struct inode *inode, struct file *file);
int ll_release_openhandle(struct dentry *, struct lookup_intent *);
int ll_md_real_close(struct inode *inode, fmode_t fmode);
extern void ll_rw_stats_tally(struct ll_sb_info *sbi, pid_t pid,
                              struct ll_file_data *file, loff_t pos,
                              size_t count, int rw);
int ll_getattr(struct vfsmount *mnt, struct dentry *de, struct kstat *stat);
struct posix_acl *ll_get_acl(struct inode *inode, int type);
int ll_migrate(struct inode *parent, struct file *file, int mdtidx,
               const char *name, int namelen);
int ll_get_fid_by_name(struct inode *parent, const char *name,
                       int namelen, struct lu_fid *fid, struct inode **inode);
#ifdef HAVE_GENERIC_PERMISSION_4ARGS
int ll_inode_permission(struct inode *inode, int mask, unsigned int flags);
#else
# ifndef HAVE_INODE_PERMISION_2ARGS
int ll_inode_permission(struct inode *inode, int mask, struct nameidata *nd);
# else
int ll_inode_permission(struct inode *inode, int mask);
# endif
#endif

int ll_lov_setstripe_ea_info(struct inode *inode, struct file *file,
                             __u64  flags, struct lov_user_md *lum,
                             int lum_size);
int ll_lov_getstripe_ea_info(struct inode *inode, const char *filename,
                             struct lov_mds_md **lmm, int *lmm_size,
                             struct ptlrpc_request **request);
int ll_dir_setstripe(struct inode *inode, struct lov_user_md *lump,
                     int set_default);
int ll_dir_getstripe(struct inode *inode, void **lmmp,
                     int *lmm_size, struct ptlrpc_request **request,
                     u64 valid);
#ifdef HAVE_FILE_FSYNC_4ARGS
int ll_fsync(struct file *file, loff_t start, loff_t end, int data);
#elif defined(HAVE_FILE_FSYNC_2ARGS)
int ll_fsync(struct file *file, int data);
#else
int ll_fsync(struct file *file, struct dentry *dentry, int data);
#endif
int ll_merge_attr(const struct lu_env *env, struct inode *inode);
int ll_fid2path(struct inode *inode, void __user *arg);
int ll_data_version(struct inode *inode, __u64 *data_version, int flags);
int ll_hsm_release(struct inode *inode);
int ll_hsm_state_set(struct inode *inode, struct hsm_state_set *hss);

/* llite/dcache.c */

int ll_d_init(struct dentry *de);
extern const struct dentry_operations ll_d_ops;
void ll_intent_drop_lock(struct lookup_intent *);
void ll_intent_release(struct lookup_intent *);
void ll_invalidate_aliases(struct inode *);
void ll_lookup_finish_locks(struct lookup_intent *it, struct dentry *dentry);
int ll_revalidate_it_finish(struct ptlrpc_request *request,
                            struct lookup_intent *it, struct dentry *de);

/* llite/llite_lib.c */
extern struct super_operations lustre_super_operations;

void ll_lli_init(struct ll_inode_info *lli);
int ll_fill_super(struct super_block *sb, struct vfsmount *mnt);
void ll_put_super(struct super_block *sb);
void ll_kill_super(struct super_block *sb);
struct inode *ll_inode_from_resource_lock(struct ldlm_lock *lock);
void ll_dir_clear_lsm_md(struct inode *inode);
void ll_clear_inode(struct inode *inode);
int ll_setattr_raw(struct dentry *dentry, struct iattr *attr, bool hsm_import);
int ll_setattr(struct dentry *de, struct iattr *attr);
int ll_statfs(struct dentry *de, struct kstatfs *sfs);
int ll_statfs_internal(struct super_block *sb, struct obd_statfs *osfs,
                       __u64 max_age, __u32 flags);
int ll_update_inode(struct inode *inode, struct lustre_md *md);
int ll_read_inode2(struct inode *inode, void *opaque);
void ll_delete_inode(struct inode *inode);
int ll_iocontrol(struct inode *inode, struct file *file,
                 unsigned int cmd, unsigned long arg);
int ll_flush_ctx(struct inode *inode);
void ll_umount_begin(struct super_block *sb);
int ll_remount_fs(struct super_block *sb, int *flags, char *data);
#ifdef HAVE_SUPEROPS_USE_DENTRY
int ll_show_options(struct seq_file *seq, struct dentry *dentry);
#else
int ll_show_options(struct seq_file *seq, struct vfsmount *vfs);
#endif
void ll_dirty_page_discard_warn(struct page *page, int ioret);
int ll_prep_inode(struct inode **inode, struct ptlrpc_request *req,
                  struct super_block *, struct lookup_intent *);
void lustre_dump_dentry(struct dentry *, int recur);
int ll_obd_statfs(struct inode *inode, void __user *arg);
int ll_get_max_mdsize(struct ll_sb_info *sbi, int *max_mdsize);
int ll_get_default_mdsize(struct ll_sb_info *sbi, int *default_mdsize);
int ll_set_default_mdsize(struct ll_sb_info *sbi, int default_mdsize);
int ll_process_config(struct lustre_cfg *lcfg);

enum {
        LUSTRE_OPC_MKDIR        = 0,
        LUSTRE_OPC_SYMLINK      = 1,
        LUSTRE_OPC_MKNOD        = 2,
        LUSTRE_OPC_CREATE       = 3,
        LUSTRE_OPC_ANY          = 5,
};

struct md_op_data *ll_prep_md_op_data(struct md_op_data *op_data,
                                      struct inode *i1, struct inode *i2,
                                      const char *name, size_t namelen,
                                      __u32 mode, __u32 opc, void *data);
void ll_finish_md_op_data(struct md_op_data *op_data);
int ll_get_obd_name(struct inode *inode, unsigned int cmd, unsigned long arg);
char *ll_get_fsname(struct super_block *sb, char *buf, int buflen);
void ll_compute_rootsquash_state(struct ll_sb_info *sbi);
ssize_t ll_copy_user_md(const struct lov_user_md __user *md,
                        struct lov_user_md **kbuf);
void ll_open_cleanup(struct super_block *sb, struct ptlrpc_request *open_req);

/* Compute expected user md size when passing in a md from user space */
static inline ssize_t ll_lov_user_md_size(const struct lov_user_md *lum)
{
        switch (lum->lmm_magic) {
        case LOV_USER_MAGIC_V1:
                return sizeof(struct lov_user_md_v1);
        case LOV_USER_MAGIC_V3:
                return sizeof(struct lov_user_md_v3);
        case LOV_USER_MAGIC_SPECIFIC:
                if (lum->lmm_stripe_count > LOV_MAX_STRIPE_COUNT)
                        return -EINVAL;

                return lov_user_md_size(lum->lmm_stripe_count,
                                        LOV_USER_MAGIC_SPECIFIC);
        }

        return -EINVAL;
}

/* llite/llite_nfs.c */
extern struct export_operations lustre_export_operations;
__u32 get_uuid2int(const char *name, int len);
struct inode *search_inode_for_lustre(struct super_block *sb,
                                      const struct lu_fid *fid);
int ll_dir_get_parent_fid(struct inode *dir, struct lu_fid *parent_fid);

/* llite/symlink.c */
extern struct inode_operations ll_fast_symlink_inode_operations;

/**
 * IO arguments for various VFS I/O interfaces.
 */
struct vvp_io_args {
        /** normal/sendfile/splice */
        enum vvp_io_subtype via_io_subtype;

        union {
                struct {
                        struct kiocb      *via_iocb;
                        struct iov_iter   *via_iter;
                } normal;
                struct {
                        struct pipe_inode_info  *via_pipe;
                        unsigned int       via_flags;
                } splice;
        } u;
};

enum lcc_type {
        LCC_RW = 1,
        LCC_MMAP
};

struct ll_cl_context {
        struct list_head         lcc_list;
        void                    *lcc_cookie;
        const struct lu_env     *lcc_env;
        struct cl_io            *lcc_io;
        struct cl_page          *lcc_page;
        enum lcc_type            lcc_type;
};

struct ll_thread_info {
        struct iov_iter         lti_iter;
        struct vvp_io_args      lti_args;
        struct ra_io_arg        lti_ria;
        struct kiocb            lti_kiocb;
        struct ll_cl_context    lti_io_ctx;
};

extern struct lu_context_key ll_thread_key;

static inline struct ll_thread_info *ll_env_info(const struct lu_env *env)
{
        struct ll_thread_info *lti;

        lti = lu_context_key_get(&env->le_ctx, &ll_thread_key);
        LASSERT(lti != NULL);

        return lti;
}

static inline struct vvp_io_args *ll_env_args(const struct lu_env *env,
                                              enum vvp_io_subtype type)
{
        struct vvp_io_args *via = &ll_env_info(env)->lti_args;

        via->via_io_subtype = type;

        return via;
}

/* llite/llite_mmap.c */

int ll_teardown_mmaps(struct address_space *mapping, __u64 first, __u64 last);
int ll_file_mmap(struct file * file, struct vm_area_struct * vma);
void policy_from_vma(union ldlm_policy_data *policy, struct vm_area_struct *vma,
                     unsigned long addr, size_t count);
struct vm_area_struct *our_vma(struct mm_struct *mm, unsigned long addr,
                               size_t count);

static inline void ll_invalidate_page(struct page *vmpage)
{
        struct address_space *mapping = vmpage->mapping;
        loff_t offset = vmpage->index << PAGE_CACHE_SHIFT;

        LASSERT(PageLocked(vmpage));
        if (mapping == NULL)
                return;

        /*
         * truncate_complete_page() calls
         * a_ops->invalidatepage()->cl_page_delete()->vvp_page_delete().
         */
        ll_teardown_mmaps(mapping, offset, offset + PAGE_CACHE_SIZE);
        truncate_complete_page(mapping, vmpage);
}

#define    ll_s2sbi(sb)        (s2lsi(sb)->lsi_llsbi)

/* don't need an addref as the sb_info should be holding one */
static inline struct obd_export *ll_s2dtexp(struct super_block *sb)
{
        return ll_s2sbi(sb)->ll_dt_exp;
}

/* don't need an addref as the sb_info should be holding one */
static inline struct obd_export *ll_s2mdexp(struct super_block *sb)
{
        return ll_s2sbi(sb)->ll_md_exp;
}

static inline struct client_obd *sbi2mdc(struct ll_sb_info *sbi)
{
        struct obd_device *obd = sbi->ll_md_exp->exp_obd;
        if (obd == NULL)
                LBUG();
        return &obd->u.cli;
}

// FIXME: replace the name of this with LL_SB to conform to kernel stuff
static inline struct ll_sb_info *ll_i2sbi(struct inode *inode)
{
        return ll_s2sbi(inode->i_sb);
}

static inline struct obd_export *ll_i2dtexp(struct inode *inode)
{
        return ll_s2dtexp(inode->i_sb);
}

static inline struct obd_export *ll_i2mdexp(struct inode *inode)
{
        return ll_s2mdexp(inode->i_sb);
}

static inline struct lu_fid *ll_inode2fid(struct inode *inode)
{
        struct lu_fid *fid;

        LASSERT(inode != NULL);
        fid = &ll_i2info(inode)->lli_fid;

        return fid;
}

static inline loff_t ll_file_maxbytes(struct inode *inode)
{
        struct cl_object *obj = ll_i2info(inode)->lli_clob;

        if (obj == NULL)
                return MAX_LFS_FILESIZE;

        return min_t(loff_t, cl_object_maxbytes(obj), MAX_LFS_FILESIZE);
}

/* llite/xattr.c */
int ll_setxattr(struct dentry *dentry, const char *name,
                const void *value, size_t size, int flags);
ssize_t ll_getxattr(struct dentry *dentry, const char *name,
                    void *buffer, size_t size);
ssize_t ll_listxattr(struct dentry *dentry, char *buffer, size_t size);
int ll_removexattr(struct dentry *dentry, const char *name);

/* llite/remote_perm.c */
extern struct kmem_cache *ll_remote_perm_cachep;
extern struct kmem_cache *ll_rmtperm_hash_cachep;

void free_rmtperm_hash(struct hlist_head *hash);
int ll_update_remote_perm(struct inode *inode, struct mdt_remote_perm *perm);
int lustre_check_remote_perm(struct inode *inode, int mask);

/**
 * Common IO arguments for various VFS I/O interfaces.
 */
int cl_sb_init(struct super_block *sb);
int cl_sb_fini(struct super_block *sb);

enum ras_update_flags {
        LL_RAS_HIT  = 0x1,
        LL_RAS_MMAP = 0x2
};
void ll_ra_count_put(struct ll_sb_info *sbi, unsigned long len);
void ll_ra_stats_inc(struct inode *inode, enum ra_stat which);

/* llite/llite_rmtacl.c */
#ifdef CONFIG_FS_POSIX_ACL
u64 rce_ops2valid(int ops);
struct rmtacl_ctl_entry *rct_search(struct rmtacl_ctl_table *rct, pid_t key);
int rct_add(struct rmtacl_ctl_table *rct, pid_t key, int ops);
int rct_del(struct rmtacl_ctl_table *rct, pid_t key);
void rct_init(struct rmtacl_ctl_table *rct);
void rct_fini(struct rmtacl_ctl_table *rct);

void ee_free(struct eacl_entry *ee);
int ee_add(struct eacl_table *et, pid_t key, struct lu_fid *fid, int type,
           ext_acl_xattr_header *header);
struct eacl_entry *et_search_del(struct eacl_table *et, pid_t key,
                                 struct lu_fid *fid, int type);
void et_search_free(struct eacl_table *et, pid_t key);
void et_init(struct eacl_table *et);
void et_fini(struct eacl_table *et);
#endif

/* statahead.c */

#define LL_SA_RPC_MIN           2
#define LL_SA_RPC_DEF           32
#define LL_SA_RPC_MAX           8192

#define LL_SA_CACHE_BIT         5
#define LL_SA_CACHE_SIZE        (1 << LL_SA_CACHE_BIT)
#define LL_SA_CACHE_MASK        (LL_SA_CACHE_SIZE - 1)

/* per inode struct, for dir only */
struct ll_statahead_info {
        struct dentry          *sai_dentry;
        atomic_t                sai_refcount;   /* when access this struct, hold
                                                 * refcount */
        unsigned int            sai_max;        /* max ahead of lookup */
        __u64                   sai_sent;       /* stat requests sent count */
        __u64                   sai_replied;    /* stat requests which received
                                                 * reply */
        __u64                   sai_index;      /* index of statahead entry */
        __u64                   sai_index_wait; /* index of entry which is the
                                                 * caller is waiting for */
        __u64                   sai_hit;        /* hit count */
        __u64                   sai_miss;       /* miss count:
                                                 * for "ls -al" case, includes
                                                 * hidden dentry miss;
                                                 * for "ls -l" case, it does not
                                                 * include hidden dentry miss.
                                                 * "sai_miss_hidden" is used for
                                                 * the later case.
                                                 */
        unsigned int            sai_consecutive_miss; /* consecutive miss */
        unsigned int            sai_miss_hidden;/* "ls -al", but first dentry
                                                 * is not a hidden one */
        unsigned int            sai_skip_hidden;/* skipped hidden dentry count
                                                 */
        unsigned int            sai_ls_all:1,   /* "ls -al", do stat-ahead for
                                                 * hidden entries */
                                sai_agl_valid:1,/* AGL is valid for the dir */
                                sai_in_readpage:1;/* statahead is in readdir()*/
        wait_queue_head_t       sai_waitq;      /* stat-ahead wait queue */
        struct ptlrpc_thread    sai_thread;     /* stat-ahead thread */
        struct ptlrpc_thread    sai_agl_thread; /* AGL thread */
        struct list_head        sai_interim_entries; /* entries which got async
                                                      * stat reply, but not
                                                      * instantiated */
        struct list_head        sai_entries;    /* completed entries */
        struct list_head        sai_agls;       /* AGLs to be sent */
        struct list_head        sai_cache[LL_SA_CACHE_SIZE];
        spinlock_t              sai_cache_lock[LL_SA_CACHE_SIZE];
        atomic_t                sai_cache_count; /* entry count in cache */
};

int ll_statahead(struct inode *dir, struct dentry **dentry, bool unplug);
void ll_authorize_statahead(struct inode *dir, void *key);
void ll_deauthorize_statahead(struct inode *dir, void *key);

/* glimpse.c */
blkcnt_t dirty_cnt(struct inode *inode);

int cl_glimpse_size0(struct inode *inode, int agl);
int cl_glimpse_lock(const struct lu_env *env, struct cl_io *io,
                    struct inode *inode, struct cl_object *clob, int agl);

static inline int cl_glimpse_size(struct inode *inode)
{
        return cl_glimpse_size0(inode, 0);
}

static inline int cl_agl(struct inode *inode)
{
        return cl_glimpse_size0(inode, 1);
}

static inline int ll_glimpse_size(struct inode *inode)
{
        struct ll_inode_info *lli = ll_i2info(inode);
        int rc;

        down_read(&lli->lli_glimpse_sem);
        rc = cl_glimpse_size(inode);
        lli->lli_glimpse_time = cfs_time_current();
        up_read(&lli->lli_glimpse_sem);
        return rc;
}

/* dentry may statahead when statahead is enabled and current process has opened
 * parent directory, and this dentry hasn't accessed statahead cache before */
static inline bool
dentry_may_statahead(struct inode *dir, struct dentry *dentry)
{
        struct ll_inode_info  *lli;
        struct ll_dentry_data *ldd;

        if (ll_i2sbi(dir)->ll_sa_max == 0)
                return false;

        lli = ll_i2info(dir);

        /* statahead is not allowed for this dir, there may be three causes:
         * 1. dir is not opened.
         * 2. statahead hit ratio is too low.
         * 3. previous stat started statahead thread failed. */
        if (!lli->lli_sa_enabled)
                return false;

        /* not the same process, don't statahead */
        if (lli->lli_opendir_pid != current_pid())
                return false;

        /*
         * When stating a dentry, kernel may trigger 'revalidate' or 'lookup'
         * multiple times, eg. for 'getattr', 'getxattr' and etc.
         * For patchless client, lookup intent is not accurate, which may
         * misguide statahead. For example:
         * The 'revalidate' call for 'getattr' and 'getxattr' of a dentry will
         * have the same intent -- IT_GETATTR, while one dentry should access
         * statahead cache once, otherwise statahead windows is messed up.
         * The solution is as following:
         * Assign 'lld_sa_generation' with 'lli_sa_generation' when a dentry
         * IT_GETATTR for the first time, and subsequent IT_GETATTR will
         * bypass interacting with statahead cache by checking
         * 'lld_sa_generation == lli->lli_sa_generation'.
         */
        ldd = ll_d2d(dentry);
        if (ldd != NULL && ldd->lld_sa_generation == lli->lli_sa_generation)
                return false;

        return true;
}

/* llite ioctl register support rountine */
enum llioc_iter {
        LLIOC_CONT = 0,
        LLIOC_STOP
};

#define LLIOC_MAX_CMD           256

/*
 * Rules to write a callback function:
 *
 * Parameters:
 *  @magic: Dynamic ioctl call routine will feed this vaule with the pointer
 *      returned to ll_iocontrol_register.  Callback functions should use this
 *      data to check the potential collasion of ioctl cmd. If collasion is
 *      found, callback function should return LLIOC_CONT.
 *  @rcp: The result of ioctl command.
 *
 *  Return values:
 *      If @magic matches the pointer returned by ll_iocontrol_data, the
 *      callback should return LLIOC_STOP; return LLIOC_STOP otherwise.
 */
typedef enum llioc_iter (*llioc_callback_t)(struct inode *inode,
                struct file *file, unsigned int cmd, unsigned long arg,
                void *magic, int *rcp);

/* export functions */
/* Register ioctl block dynamatically for a regular file.
 *
 * @cmd: the array of ioctl command set
 * @count: number of commands in the @cmd
 * @cb: callback function, it will be called if an ioctl command is found to
 *      belong to the command list @cmd.
 *
 * Return vaule:
 *      A magic pointer will be returned if success;
 *      otherwise, NULL will be returned.
 * */
void *ll_iocontrol_register(llioc_callback_t cb, int count, unsigned int *cmd);
void ll_iocontrol_unregister(void *magic);

int cl_sync_file_range(struct inode *inode, loff_t start, loff_t end,
                       enum cl_fsync_mode mode, int ignore_layout);

/** direct write pages */
struct ll_dio_pages {
        /** page array to be written. we don't support
         * partial pages except the last one. */
        struct page **ldp_pages;
        /* offset of each page */
        loff_t       *ldp_offsets;
        /** if ldp_offsets is NULL, it means a sequential
         * pages to be written, then this is the file offset
         * of the * first page. */
        loff_t        ldp_start_offset;
        /** how many bytes are to be written. */
        size_t        ldp_size;
        /** # of pages in the array. */
        int           ldp_nr;
};

extern ssize_t ll_direct_rw_pages(const struct lu_env *env, struct cl_io *io,
                                  int rw, struct inode *inode,
                                  struct ll_dio_pages *pv);

static inline int ll_file_nolock(const struct file *file)
{
        struct ll_file_data *fd = LUSTRE_FPRIVATE(file);
        struct inode *inode = file->f_path.dentry->d_inode;

        LASSERT(fd != NULL);
        return ((fd->fd_flags & LL_FILE_IGNORE_LOCK) ||
                (ll_i2sbi(inode)->ll_flags & LL_SBI_NOLCK));
}

static inline void ll_set_lock_data(struct obd_export *exp, struct inode *inode,
                                    struct lookup_intent *it, __u64 *bits)
{
        if (!it->it_lock_set) {
                struct lustre_handle handle;

                /* If this inode is a remote object, it will get two
                 * separate locks in different namespaces, Master MDT,
                 * where the name entry is, will grant LOOKUP lock,
                 * remote MDT, where the object is, will grant
                 * UPDATE|PERM lock. The inode will be attched to both
                 * LOOKUP and PERM locks, so revoking either locks will
                 * case the dcache being cleared */
                if (it->it_remote_lock_mode) {
                        handle.cookie = it->it_remote_lock_handle;
                        CDEBUG(D_DLMTRACE, "setting l_data to inode "DFID
                               "(%p) for remote lock "LPX64"\n",
                               PFID(ll_inode2fid(inode)), inode,
                               handle.cookie);
                        md_set_lock_data(exp, &handle.cookie, inode, NULL);
                }

                handle.cookie = it->it_lock_handle;

                CDEBUG(D_DLMTRACE, "setting l_data to inode "DFID"(%p)"
                       " for lock "LPX64"\n",
                       PFID(ll_inode2fid(inode)), inode, handle.cookie);

                md_set_lock_data(exp, &handle.cookie, inode,
                                 &it->it_lock_bits);
                it->it_lock_set = 1;
        }

        if (bits != NULL)
                *bits = it->it_lock_bits;
}

static inline void ll_lock_dcache(struct inode *inode)
{
#ifdef HAVE_DCACHE_LOCK
        spin_lock(&dcache_lock);
#else
        spin_lock(&inode->i_lock);
#endif
}

static inline void ll_unlock_dcache(struct inode *inode)
{
#ifdef HAVE_DCACHE_LOCK
        spin_unlock(&dcache_lock);
#else
        spin_unlock(&inode->i_lock);
#endif
}

static inline int d_lustre_invalid(const struct dentry *dentry)
{
        struct ll_dentry_data *lld = ll_d2d(dentry);

        return (lld == NULL) || lld->lld_invalid;
}

static inline void __d_lustre_invalidate(struct dentry *dentry)
{
        struct ll_dentry_data *lld = ll_d2d(dentry);

        if (lld != NULL)
                lld->lld_invalid = 1;
}

/*
 * Mark dentry INVALID, if dentry refcount is zero (this is normally case for
 * ll_md_blocking_ast), unhash this dentry, and let dcache to reclaim it later;
 * else dput() of the last refcount will unhash this dentry and kill it.
 */
static inline void d_lustre_invalidate(struct dentry *dentry, int nested)
{
        CDEBUG(D_DENTRY, "invalidate dentry %.*s (%p) parent %p inode %p "
               "refc %d\n", dentry->d_name.len, dentry->d_name.name, dentry,
               dentry->d_parent, dentry->d_inode, ll_d_count(dentry));

        spin_lock_nested(&dentry->d_lock,
                         nested ? DENTRY_D_LOCK_NESTED : DENTRY_D_LOCK_NORMAL);
        __d_lustre_invalidate(dentry);
        /*
         * We should be careful about dentries created by d_obtain_alias().
         * These dentries are not put in the dentry tree, instead they are
         * linked to sb->s_anon through dentry->d_hash.
         * shrink_dcache_for_umount() shrinks the tree and sb->s_anon list.
         * If we unhashed such a dentry, unmount would not be able to find
         * it and busy inodes would be reported.
         */
        if (ll_d_count(dentry) == 0 && !(dentry->d_flags & DCACHE_DISCONNECTED))
                __d_drop(dentry);
        spin_unlock(&dentry->d_lock);
}

static inline void d_lustre_revalidate(struct dentry *dentry)
{
        spin_lock(&dentry->d_lock);
        LASSERT(ll_d2d(dentry) != NULL);
        ll_d2d(dentry)->lld_invalid = 0;
        spin_unlock(&dentry->d_lock);
}

int ll_layout_conf(struct inode *inode, const struct cl_object_conf *conf);
int ll_layout_refresh(struct inode *inode, __u32 *gen);
int ll_layout_restore(struct inode *inode, loff_t start, __u64 length);

int ll_xattr_init(void);
void ll_xattr_fini(void);

int ll_getxattr_common(struct inode *inode, const char *name,
                       void *buffer, size_t size, __u64 valid);
int ll_page_sync_io(const struct lu_env *env, struct cl_io *io,
                    struct cl_page *page, enum cl_req_type crt);

int ll_getparent(struct file *file, struct getparent __user *arg);

/* lcommon_cl.c */
int cl_setattr_ost(struct cl_object *obj, const struct iattr *attr,
                   unsigned int attr_flags);

extern struct lu_env *cl_inode_fini_env;
extern __u16 cl_inode_fini_refcheck;

int cl_file_inode_init(struct inode *inode, struct lustre_md *md);
void cl_inode_fini(struct inode *inode);

u64 cl_fid_build_ino(const struct lu_fid *fid, int api32);
u32 cl_fid_build_gen(const struct lu_fid *fid);

#ifndef HAVE_FILE_INODE
static inline struct inode *file_inode(struct file *file)
{
        return file->f_path.dentry->d_inode;
}
#endif

#ifndef HAVE_IOV_ITER_TRUNCATE
static inline void iov_iter_truncate(struct iov_iter *i, u64 count)
{
        if (i->count > count)
                i->count = count;
}
#endif

#ifndef HAVE_FILE_OPERATIONS_READ_WRITE_ITER
static inline void iov_iter_reexpand(struct iov_iter *i, size_t count)
{
        i->count = count;
}

static inline struct iovec iov_iter_iovec(const struct iov_iter *iter)
{
        return (struct iovec) {
                .iov_base = iter->iov->iov_base + iter->iov_offset,
                .iov_len = min(iter->count,
                               iter->iov->iov_len - iter->iov_offset),
        };
}

#define iov_for_each(iov, iter, start)                                  \
        for (iter = (start);                                            \
             (iter).count && ((iov = iov_iter_iovec(&(iter))), 1);      \
             iov_iter_advance(&(iter), (iov).iov_len))

static inline ssize_t
generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
{
        struct iovec iov;
        struct iov_iter i;
        ssize_t bytes = 0;

        iov_for_each(iov, i, *iter) {
                ssize_t res;

                res = generic_file_aio_read(iocb, &iov, 1, iocb->ki_pos);
                if (res <= 0) {
                        if (bytes == 0)
                                bytes = res;
                        break;
                }

                bytes += res;
                if (res < iov.iov_len)
                        break;
        }

        if (bytes > 0)
                iov_iter_advance(iter, bytes);
        return bytes;
}

static inline ssize_t
generic_file_write_iter(struct kiocb *iocb, struct iov_iter *iter)
{
        struct iovec iov;
        struct iov_iter i;
        ssize_t bytes = 0;

        iov_for_each(iov, i, *iter) {
                ssize_t res;

                res = __generic_file_aio_write(iocb, &iov, 1, &iocb->ki_pos);
                if (res <= 0) {
                        if (bytes == 0)
                                bytes = res;
                        break;
                }

                bytes += res;
                if (res < iov.iov_len)
                        break;
        }

        if (bytes > 0)
                iov_iter_advance(iter, bytes);
        return bytes;
}
#endif /* HAVE_FILE_OPERATIONS_READ_WRITE_ITER */
#endif /* LLITE_INTERNAL_H */