/*      $NetBSD: vnode_impl.h,v 1.27 2023/08/01 16:33:43 dholland Exp $ */

/*-
 * Copyright (c) 2016, 2019, 2020 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef _SYS_VNODE_IMPL_H_
#define _SYS_VNODE_IMPL_H_
#if defined(_KERNEL) || defined(_KMEMUSER)

#include <sys/sdt.h>
#include <sys/vnode.h>

struct namecache;
struct nchnode;

enum vnode_state {
        VS_ACTIVE,      /* Assert only, fs node attached and usecount > 0. */
        VS_MARKER,      /* Stable, used as marker. Will not change. */
        VS_LOADING,     /* Intermediate, initialising the fs node. */
        VS_LOADED,      /* Stable, valid fs node attached. */
        VS_BLOCKED,     /* Intermediate, active, no new references allowed. */
        VS_RECLAIMING,  /* Intermediate, detaching the fs node. */
        VS_RECLAIMED    /* Stable, no fs node attached. */
};

TAILQ_HEAD(vnodelst, vnode_impl);
typedef struct vnodelst vnodelst_t;

struct vcache_key {
        struct mount *vk_mount;
        const void *vk_key;
        size_t vk_key_len;
};

/*
 * Reading or writing any of these items requires holding the appropriate
 * lock.  Field markings and the corresponding locks:
 *
 *      -       stable throughout the life of the vnode
 *      c       vcache_lock
 *      d       vdrain_lock
 *      i       v_interlock
 *      l       vi_nc_listlock
 *      m       mnt_vnodelock
 *      n       vi_nc_lock
 *      n,l     both vi_nc_lock + vi_nc_listlock to modify, either to read
 *      s       syncer_data_lock
 */
struct vnode_impl {
        struct vnode vi_vnode;

        /*
         * Largely stable data.
         */
        struct vcache_key vi_key;               /* c   vnode cache key */

        /*
         * The vnode klist is accessed frequently, but rarely
         * modified.
         */
        struct vnode_klist vi_klist;            /* i   kevent / knote state */

        /*
         * vnode cache, LRU and syncer.  This all changes with some
         * regularity so keep it together.
         */
        struct vnodelst *vi_lrulisthd;          /* d   current lru list head */
        TAILQ_ENTRY(vnode_impl) vi_lrulist;     /* d   lru list */
        int             vi_synclist_slot;       /* s   synclist slot index */
        int             vi_lrulisttm;           /* i   time of lru enqueue */
        TAILQ_ENTRY(vnode_impl) vi_synclist;    /* s   vnodes with dirty bufs */
        SLIST_ENTRY(vnode_impl) vi_hash;        /* c   vnode cache list */
        enum vnode_state vi_state;              /* i   current state */
        TAILQ_ENTRY(vnode_impl) vi_mntvnodes;   /* m   vnodes for mount point */

        /*
         * Namecache.  Give it a separate line so activity doesn't impinge
         * on the stable stuff.
         */
        rb_tree_t       vi_nc_tree              /* n   namecache tree */
            __aligned(COHERENCY_UNIT);
        TAILQ_HEAD(,namecache) vi_nc_list;      /* l   namecaches (parent) */
        mode_t          vi_nc_mode;             /* n,l cached mode or VNOVAL */
        uid_t           vi_nc_uid;              /* n,l cached UID or VNOVAL */
        gid_t           vi_nc_gid;              /* n,l cached GID or VNOVAL */
        uint32_t        vi_nc_spare;            /* -   spare (padding) */

        /*
         * Locks and expensive to access items which can be expected to
         * generate a cache miss.
         */
        krwlock_t       vi_lock                 /* -   lock for this vnode */
            __aligned(COHERENCY_UNIT);
        krwlock_t       vi_nc_lock              /* -   lock on node */
            __aligned(COHERENCY_UNIT);
        krwlock_t       vi_nc_listlock;         /* -   lock on nn_list */
};
typedef struct vnode_impl vnode_impl_t;

#define VIMPL_TO_VNODE(vip)     (&(vip)->vi_vnode)
#define VNODE_TO_VIMPL(vp)      container_of((vp), struct vnode_impl, vi_vnode)

/*
 * Vnode state assertion.
 */
void _vstate_assert(vnode_t *, enum vnode_state, const char *, int, bool);

#if defined(DIAGNOSTIC)

#define VSTATE_ASSERT(vp, state) \
        _vstate_assert((vp), (state), __func__, __LINE__, true)
#define VSTATE_ASSERT_UNLOCKED(vp, state) \
        _vstate_assert((vp), (state), __func__, __LINE__, false)

#else /* defined(DIAGNOSTIC) */

#define VSTATE_ASSERT(vp, state)
#define VSTATE_ASSERT_UNLOCKED(vp, state)

#endif /* defined(DIAGNOSTIC) */

/*
 * Vnode manipulation functions.
 */
const char *
        vstate_name(enum vnode_state);
vnode_t *
        vnalloc_marker(struct mount *);
void    vnfree_marker(vnode_t *);
bool    vnis_marker(vnode_t *);
void    vcache_make_anon(vnode_t *);
int     vcache_vget(vnode_t *);
int     vcache_tryvget(vnode_t *);
int     vfs_drainvnodes(void);

SDT_PROVIDER_DECLARE(vfs);

#endif  /* defined(_KERNEL) || defined(_KMEMUSER) */
#endif  /* !_SYS_VNODE_IMPL_H_ */