/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1989, 1991, 1993
 *      The Regents of the University of California.  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.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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_MOUNT_H_
#define _SYS_MOUNT_H_

#include <sys/types.h>
#include <sys/ucred.h>
#include <sys/queue.h>
#ifdef _KERNEL
#include <sys/lock.h>
#include <sys/lockmgr.h>
#include <sys/tslog.h>
#include <sys/_mutex.h>
#include <sys/_sx.h>
#elif defined(_WANT_MOUNT)
#include <sys/_lock.h>
#include <sys/_lockmgr.h>
#include <sys/_mutex.h>
#endif

/*
 * NOTE: When changing statfs structure, mount structure, MNT_* flags or
 * MNTK_* flags also update DDB show mount command in vfs_subr.c.
 */

typedef struct fsid { int32_t val[2]; } fsid_t; /* filesystem id type */

/* Returns non-zero if fsids are different. */
static __inline int
fsidcmp(const fsid_t *a, const fsid_t *b)
{
        return (a->val[0] != b->val[0] || a->val[1] != b->val[1]);
}

/*
 * File identifier.
 * These are unique per filesystem on a single machine.
 *
 * Note that the offset of fid_data is 4 bytes, so care must be taken to avoid
 * undefined behavior accessing unaligned fields within an embedded struct.
 */
#define MAXFIDSZ        16

struct fid {
        u_short         fid_len;                /* length of data in bytes */
        u_short         fid_data0;              /* force longword alignment */
        char            fid_data[MAXFIDSZ];     /* data (variable length) */
};

/*
 * filesystem statistics
 */
#define MFSNAMELEN      16              /* length of type name including null */
#define MNAMELEN        1024            /* size of on/from name bufs */
#define STATFS_VERSION  0x20140518      /* current version number */
struct statfs {
        uint32_t f_version;             /* structure version number */
        uint32_t f_type;                /* type of filesystem */
        uint64_t f_flags;               /* copy of mount exported flags */
        uint64_t f_bsize;               /* filesystem fragment size */
        uint64_t f_iosize;              /* optimal transfer block size */
        uint64_t f_blocks;              /* total data blocks in filesystem */
        uint64_t f_bfree;               /* free blocks in filesystem */
        int64_t  f_bavail;              /* free blocks avail to non-superuser */
        uint64_t f_files;               /* total file nodes in filesystem */
        int64_t  f_ffree;               /* free nodes avail to non-superuser */
        uint64_t f_syncwrites;          /* count of sync writes since mount */
        uint64_t f_asyncwrites;         /* count of async writes since mount */
        uint64_t f_syncreads;           /* count of sync reads since mount */
        uint64_t f_asyncreads;          /* count of async reads since mount */
        uint32_t f_nvnodelistsize;      /* # of vnodes */
        uint32_t f_spare0;              /* unused spare */
        uint64_t f_spare[9];            /* unused spare */
        uint32_t f_namemax;             /* maximum filename length */
        uid_t     f_owner;              /* user that mounted the filesystem */
        fsid_t    f_fsid;               /* filesystem id */
        char      f_charspare[80];          /* spare string space */
        char      f_fstypename[MFSNAMELEN]; /* filesystem type name */
        char      f_mntfromname[MNAMELEN];  /* mounted filesystem */
        char      f_mntonname[MNAMELEN];    /* directory on which mounted */
};

#if defined(_WANT_FREEBSD11_STATFS) || defined(_KERNEL)
#define FREEBSD11_STATFS_VERSION        0x20030518 /* current version number */
struct freebsd11_statfs {
        uint32_t f_version;             /* structure version number */
        uint32_t f_type;                /* type of filesystem */
        uint64_t f_flags;               /* copy of mount exported flags */
        uint64_t f_bsize;               /* filesystem fragment size */
        uint64_t f_iosize;              /* optimal transfer block size */
        uint64_t f_blocks;              /* total data blocks in filesystem */
        uint64_t f_bfree;               /* free blocks in filesystem */
        int64_t  f_bavail;              /* free blocks avail to non-superuser */
        uint64_t f_files;               /* total file nodes in filesystem */
        int64_t  f_ffree;               /* free nodes avail to non-superuser */
        uint64_t f_syncwrites;          /* count of sync writes since mount */
        uint64_t f_asyncwrites;         /* count of async writes since mount */
        uint64_t f_syncreads;           /* count of sync reads since mount */
        uint64_t f_asyncreads;          /* count of async reads since mount */
        uint64_t f_spare[10];           /* unused spare */
        uint32_t f_namemax;             /* maximum filename length */
        uid_t     f_owner;              /* user that mounted the filesystem */
        fsid_t    f_fsid;               /* filesystem id */
        char      f_charspare[80];      /* spare string space */
        char      f_fstypename[16];     /* filesystem type name */
        char      f_mntfromname[88];    /* mounted filesystem */
        char      f_mntonname[88];      /* directory on which mounted */
};
#endif /* _WANT_FREEBSD11_STATFS || _KERNEL */

#ifdef _KERNEL
#define OMFSNAMELEN     16      /* length of fs type name, including null */
#define OMNAMELEN       (88 - 2 * sizeof(long)) /* size of on/from name bufs */

/* XXX getfsstat.2 is out of date with write and read counter changes here. */
/* XXX statfs.2 is out of date with read counter changes here. */
struct ostatfs {
        long    f_spare2;               /* placeholder */
        long    f_bsize;                /* fundamental filesystem block size */
        long    f_iosize;               /* optimal transfer block size */
        long    f_blocks;               /* total data blocks in filesystem */
        long    f_bfree;                /* free blocks in fs */
        long    f_bavail;               /* free blocks avail to non-superuser */
        long    f_files;                /* total file nodes in filesystem */
        long    f_ffree;                /* free file nodes in fs */
        fsid_t  f_fsid;                 /* filesystem id */
        uid_t   f_owner;                /* user that mounted the filesystem */
        int     f_type;                 /* type of filesystem */
        int     f_flags;                /* copy of mount exported flags */
        long    f_syncwrites;           /* count of sync writes since mount */
        long    f_asyncwrites;          /* count of async writes since mount */
        char    f_fstypename[OMFSNAMELEN]; /* fs type name */
        char    f_mntonname[OMNAMELEN]; /* directory on which mounted */
        long    f_syncreads;            /* count of sync reads since mount */
        long    f_asyncreads;           /* count of async reads since mount */
        short   f_spares1;              /* unused spare */
        char    f_mntfromname[OMNAMELEN];/* mounted filesystem */
        short   f_spares2;              /* unused spare */
        /*
         * XXX on machines where longs are aligned to 8-byte boundaries, there
         * is an unnamed int32_t here.  This spare was after the apparent end
         * of the struct until we bit off the read counters from f_mntonname.
         */
        long    f_spare[2];             /* unused spare */
};
#endif  /* _KERNEL */

#if defined(_WANT_MOUNT) || defined(_KERNEL)
TAILQ_HEAD(vnodelst, vnode);

/* Mount options list */
TAILQ_HEAD(vfsoptlist, vfsopt);
struct vfsopt {
        TAILQ_ENTRY(vfsopt) link;
        char    *name;
        void    *value;
        int     len;
        int     pos;
        int     seen;
};

struct mount_pcpu {
        int             mntp_thread_in_ops;
        int             mntp_ref;
        int             mntp_lockref;
        int             mntp_writeopcount;
};

_Static_assert(sizeof(struct mount_pcpu) == 16,
    "the struct is allocated from pcpu 16 zone");

/*
 * Structure for tracking a stacked filesystem mounted above another
 * filesystem.  This is expected to be stored in the upper FS' per-mount data.
 *
 * Lock reference:
 *      i - lower mount interlock
 *      c - constant from node initialization
 */
struct mount_upper_node {
        struct mount    *mp;    /* (c) mount object for upper FS */
        TAILQ_ENTRY(mount_upper_node) mnt_upper_link;   /* (i) position in uppers list */
};

/*
 * Structure per mounted filesystem.  Each mounted filesystem has an
 * array of operations and an instance record.  The filesystems are
 * put on a doubly linked list.
 *
 * Lock reference:
 *      l - mnt_listmtx
 *      m - mountlist_mtx
 *      i - interlock
 *      v - vnode freelist mutex
 *      d - deferred unmount list mutex
 *      e - mnt_explock
 *
 * Unmarked fields are considered stable as long as a ref is held.
 *
 */
struct mount {
        int             mnt_vfs_ops;            /* (i) pending vfs ops */
        int             mnt_kern_flag;          /* (i) kernel only flags */
        uint64_t        mnt_flag;               /* (i) flags shared with user */
        struct mount_pcpu *mnt_pcpu;            /* per-CPU data */
        struct vnode    *mnt_rootvnode;
        struct vnode    *mnt_vnodecovered;      /* vnode we mounted on */
        struct vfsops   *mnt_op;                /* operations on fs */
        struct vfsconf  *mnt_vfc;               /* configuration info */
        struct mtx __aligned(CACHE_LINE_SIZE)   mnt_mtx; /* mount structure interlock */
        int             mnt_gen;                /* struct mount generation */
#define mnt_startzero   mnt_list
        TAILQ_ENTRY(mount) mnt_list;            /* (m) mount list */
        struct vnode    *mnt_syncer;            /* syncer vnode */
        int             mnt_ref;                /* (i) Reference count */
        struct vnodelst mnt_nvnodelist;         /* (i) list of vnodes */
        int             mnt_nvnodelistsize;     /* (i) # of vnodes */
        int             mnt_writeopcount;       /* (i) write syscalls pending */
        struct vfsoptlist *mnt_opt;             /* current mount options */
        struct vfsoptlist *mnt_optnew;          /* new options passed to fs */
        struct statfs   mnt_stat;               /* cache of filesystem stats */
        struct ucred    *mnt_cred;              /* credentials of mounter */
        void *          mnt_data;               /* private data */
        time_t          mnt_time;               /* last time written*/
        int             mnt_iosize_max;         /* max size for clusters, etc */
        struct netexport *mnt_export;           /* (e) export list */
        struct label    *mnt_label;             /* MAC label for the fs */
        u_int           mnt_hashseed;           /* Random seed for vfs_hash */
        int             mnt_lockref;            /* (i) Lock reference count */
        int             mnt_secondary_writes;   /* (i) # of secondary writes */
        int             mnt_secondary_accwrites;/* (i) secondary wr. starts */
        struct thread   *mnt_susp_owner;        /* (i) thread owning suspension */
        struct ucred    *mnt_exjail;            /* (i) jail which did exports */
#define mnt_endzero     mnt_gjprovider
        char            *mnt_gjprovider;        /* gjournal provider name */
        struct mtx      mnt_listmtx;
        struct vnodelst mnt_lazyvnodelist;      /* (l) list of lazy vnodes */
        int             mnt_lazyvnodelistsize;  /* (l) # of lazy vnodes */
        int             mnt_upper_pending;      /* (i) # of pending ops on mnt_uppers */
        struct lock     mnt_explock;            /* vfs_export walkers lock */
        struct lock     mnt_renamelock;         /* renames and O_RESOLVE_BENEATH */
        TAILQ_HEAD(, mount_upper_node) mnt_uppers; /* (i) upper mounts over us */
        TAILQ_HEAD(, mount_upper_node) mnt_notify; /* (i) upper mounts for notification */
        STAILQ_ENTRY(mount) mnt_taskqueue_link; /* (d) our place in deferred unmount list */
        uint64_t        mnt_taskqueue_flags;    /* (d) unmount flags passed from taskqueue */
        unsigned int    mnt_unmount_retries;    /* (d) # of failed deferred unmount attempts */
};
#endif  /* _WANT_MOUNT || _KERNEL */

#ifdef _KERNEL
/*
 * Definitions for MNT_VNODE_FOREACH_ALL.
 */
struct vnode *__mnt_vnode_next_all(struct vnode **mvp, struct mount *mp);
struct vnode *__mnt_vnode_first_all(struct vnode **mvp, struct mount *mp);
void          __mnt_vnode_markerfree_all(struct vnode **mvp, struct mount *mp);

#define MNT_VNODE_FOREACH_ALL(vp, mp, mvp)                              \
        for (vp = __mnt_vnode_first_all(&(mvp), (mp));                  \
                (vp) != NULL; vp = __mnt_vnode_next_all(&(mvp), (mp)))

#define MNT_VNODE_FOREACH_ALL_ABORT(mp, mvp)                            \
        do {                                                            \
                MNT_ILOCK(mp);                                          \
                __mnt_vnode_markerfree_all(&(mvp), (mp));               \
                /* MNT_IUNLOCK(mp); -- done in above function */        \
                mtx_assert(MNT_MTX(mp), MA_NOTOWNED);                   \
        } while (0)

/*
 * Definitions for MNT_VNODE_FOREACH_LAZY.
 */
typedef int mnt_lazy_cb_t(struct vnode *, void *);
struct vnode *__mnt_vnode_next_lazy(struct vnode **mvp, struct mount *mp,
    mnt_lazy_cb_t *cb, void *cbarg);
struct vnode *__mnt_vnode_first_lazy(struct vnode **mvp, struct mount *mp,
    mnt_lazy_cb_t *cb, void *cbarg);
void          __mnt_vnode_markerfree_lazy(struct vnode **mvp, struct mount *mp);

#define MNT_VNODE_FOREACH_LAZY(vp, mp, mvp, cb, cbarg)                  \
        for (vp = __mnt_vnode_first_lazy(&(mvp), (mp), (cb), (cbarg));  \
                (vp) != NULL;                                           \
                vp = __mnt_vnode_next_lazy(&(mvp), (mp), (cb), (cbarg)))

#define MNT_VNODE_FOREACH_LAZY_ABORT(mp, mvp)                           \
        __mnt_vnode_markerfree_lazy(&(mvp), (mp))

#define MNT_ILOCK(mp)   mtx_lock(&(mp)->mnt_mtx)
#define MNT_ITRYLOCK(mp) mtx_trylock(&(mp)->mnt_mtx)
#define MNT_IUNLOCK(mp) mtx_unlock(&(mp)->mnt_mtx)
#define MNT_MTX(mp)     (&(mp)->mnt_mtx)

#define MNT_REF(mp)     do {                                            \
        mtx_assert(MNT_MTX(mp), MA_OWNED);                              \
        mp->mnt_ref++;                                                  \
} while (0)
#define MNT_REL(mp)     do {                                            \
        mtx_assert(MNT_MTX(mp), MA_OWNED);                              \
        (mp)->mnt_ref--;                                                \
        if ((mp)->mnt_vfs_ops && (mp)->mnt_ref < 0)             \
                vfs_dump_mount_counters(mp);                            \
        if ((mp)->mnt_ref == 0 && (mp)->mnt_vfs_ops)            \
                wakeup((mp));                                           \
} while (0)

#endif /* _KERNEL */

#if defined(_WANT_MNTOPTNAMES) || defined(_KERNEL)
struct mntoptnames {
        uint64_t o_opt;
        const char *o_name;
};
#define MNTOPT_NAMES                                                    \
        { MNT_ASYNC,            "asynchronous" },                       \
        { MNT_EXPORTED,         "NFS exported" },                       \
        { MNT_LOCAL,            "local" },                              \
        { MNT_NOATIME,          "noatime" },                            \
        { MNT_NOEXEC,           "noexec" },                             \
        { MNT_NOSUID,           "nosuid" },                             \
        { MNT_NOSYMFOLLOW,      "nosymfollow" },                        \
        { MNT_QUOTA,            "with quotas" },                        \
        { MNT_RDONLY,           "read-only" },                          \
        { MNT_SYNCHRONOUS,      "synchronous" },                        \
        { MNT_UNION,            "union" },                              \
        { MNT_NOCLUSTERR,       "noclusterr" },                         \
        { MNT_NOCLUSTERW,       "noclusterw" },                         \
        { MNT_SUIDDIR,          "suiddir" },                            \
        { MNT_SOFTDEP,          "soft-updates" },                       \
        { MNT_SUJ,              "journaled soft-updates" },             \
        { MNT_MULTILABEL,       "multilabel" },                         \
        { MNT_ACLS,             "acls" },                               \
        { MNT_NFS4ACLS,         "nfsv4acls" },                          \
        { MNT_GJOURNAL,         "gjournal" },                           \
        { MNT_AUTOMOUNTED,      "automounted" },                        \
        { MNT_VERIFIED,         "verified" },                           \
        { MNT_UNTRUSTED,        "untrusted" },                          \
        { MNT_NOCOVER,          "nocover" },                            \
        { MNT_EMPTYDIR,         "emptydir" },                           \
        { MNT_UPDATE,           "update" },                             \
        { MNT_DELEXPORT,        "delexport" },                          \
        { MNT_RELOAD,           "reload" },                             \
        { MNT_FORCE,            "force" },                              \
        { MNT_SNAPSHOT,         "snapshot" },                           \
        { MNT_NAMEDATTR,        "named attributes" },                   \
        { 0, NULL }
#endif

/*
 * User specifiable flags, stored in mnt_flag.
 */
#define MNT_RDONLY      0x0000000000000001ULL /* read only filesystem */
#define MNT_SYNCHRONOUS 0x0000000000000002ULL /* fs written synchronously */
#define MNT_NOEXEC      0x0000000000000004ULL /* can't exec from filesystem */
#define MNT_NOSUID      0x0000000000000008ULL /* don't honor setuid fs bits */
#define MNT_NFS4ACLS    0x0000000000000010ULL /* enable NFS version 4 ACLs */
#define MNT_UNION       0x0000000000000020ULL /* union with underlying fs */
#define MNT_ASYNC       0x0000000000000040ULL /* fs written asynchronously */
#define MNT_SUIDDIR     0x0000000000100000ULL /* special SUID dir handling */
#define MNT_SOFTDEP     0x0000000000200000ULL /* using soft updates */
#define MNT_NOSYMFOLLOW 0x0000000000400000ULL /* do not follow symlinks */
#define MNT_GJOURNAL    0x0000000002000000ULL /* GEOM journal support enabled */
#define MNT_MULTILABEL  0x0000000004000000ULL /* MAC support for objects */
#define MNT_ACLS        0x0000000008000000ULL /* ACL support enabled */
#define MNT_NOATIME     0x0000000010000000ULL /* dont update file access time */
#define MNT_NOCLUSTERR  0x0000000040000000ULL /* disable cluster read */
#define MNT_NOCLUSTERW  0x0000000080000000ULL /* disable cluster write */
#define MNT_SUJ         0x0000000100000000ULL /* using journaled soft updates */
#define MNT_AUTOMOUNTED 0x0000000200000000ULL /* mounted by automountd(8) */
#define MNT_UNTRUSTED   0x0000000800000000ULL /* filesys metadata untrusted */
#define MNT_NAMEDATTR   0x0000020000000000ULL /* named attributes enabled */

/*
 * NFS export related mount flags.
 */
#define MNT_EXRDONLY    0x0000000000000080ULL   /* exported read only */
#define MNT_EXPORTED    0x0000000000000100ULL   /* filesystem is exported */
#define MNT_DEFEXPORTED 0x0000000000000200ULL   /* exported to the world */
#define MNT_EXPORTANON  0x0000000000000400ULL   /* anon uid mapping for all */
#define MNT_EXKERB      0x0000000000000800ULL   /* exported with Kerberos */
#define MNT_EXPUBLIC    0x0000000020000000ULL   /* public export (WebNFS) */
#define MNT_EXTLS       0x0000004000000000ULL /* require TLS */
#define MNT_EXTLSCERT   0x0000008000000000ULL /* require TLS with client cert */
#define MNT_EXTLSCERTUSER 0x0000010000000000ULL /* require TLS with user cert */

/*
 * Flags set by internal operations, but visible to the user.
 */
#define MNT_LOCAL       0x0000000000001000ULL /* filesystem is stored locally */
#define MNT_QUOTA       0x0000000000002000ULL /* quotas are enabled on fs */
#define MNT_ROOTFS      0x0000000000004000ULL /* identifies the root fs */
#define MNT_USER        0x0000000000008000ULL /* mounted by a user */
#define MNT_IGNORE      0x0000000000800000ULL /* do not show entry in df */
#define MNT_VERIFIED    0x0000000400000000ULL /* filesystem is verified */

/*
 * Mask of flags that are visible to statfs().
 * XXX I think that this could now become (~(MNT_CMDFLAGS))
 * but the 'mount' program may need changing to handle this.
 */
#define MNT_VISFLAGMASK (MNT_RDONLY     | MNT_SYNCHRONOUS | MNT_NOEXEC  | \
                        MNT_NOSUID      | MNT_UNION     | MNT_SUJ       | \
                        MNT_ASYNC       | MNT_EXRDONLY  | MNT_EXPORTED  | \
                        MNT_DEFEXPORTED | MNT_EXPORTANON| MNT_EXKERB    | \
                        MNT_LOCAL       | MNT_USER      | MNT_QUOTA     | \
                        MNT_ROOTFS      | MNT_NOATIME   | MNT_NOCLUSTERR| \
                        MNT_NOCLUSTERW  | MNT_SUIDDIR   | MNT_SOFTDEP   | \
                        MNT_IGNORE      | MNT_EXPUBLIC  | MNT_NOSYMFOLLOW | \
                        MNT_GJOURNAL    | MNT_MULTILABEL | MNT_ACLS     | \
                        MNT_NFS4ACLS    | MNT_AUTOMOUNTED | MNT_VERIFIED | \
                        MNT_UNTRUSTED   | MNT_NAMEDATTR)

/* Mask of flags that can be updated. */
#define MNT_UPDATEMASK (MNT_NOSUID      | MNT_NOEXEC    | \
                        MNT_SYNCHRONOUS | MNT_UNION     | MNT_ASYNC     | \
                        MNT_NOATIME | \
                        MNT_NOSYMFOLLOW | MNT_IGNORE    | \
                        MNT_NOCLUSTERR  | MNT_NOCLUSTERW | MNT_SUIDDIR  | \
                        MNT_ACLS        | MNT_USER      | MNT_NFS4ACLS  | \
                        MNT_AUTOMOUNTED | MNT_UNTRUSTED)

/*
 * External filesystem command modifier flags.
 * Unmount can use the MNT_FORCE flag.
 * XXX: These are not STATES and really should be somewhere else.
 * XXX: MNT_BYFSID and MNT_NONBUSY collide with MNT_ACLS and MNT_MULTILABEL,
 *      but because MNT_ACLS and MNT_MULTILABEL are only used for mount(2),
 *      and MNT_BYFSID and MNT_NONBUSY are only used for unmount(2),
 *      it's harmless.
 */
#define MNT_UPDATE      0x0000000000010000ULL /* not real mount, just update */
#define MNT_DELEXPORT   0x0000000000020000ULL /* delete export host lists */
#define MNT_RELOAD      0x0000000000040000ULL /* reload filesystem data */
#define MNT_FORCE       0x0000000000080000ULL /* force unmount or readonly */
#define MNT_SNAPSHOT    0x0000000001000000ULL /* snapshot the filesystem */
#define MNT_NONBUSY     0x0000000004000000ULL /* check vnode use counts. */
#define MNT_BYFSID      0x0000000008000000ULL /* specify filesystem by ID. */
#define MNT_NOCOVER     0x0000001000000000ULL /* Do not cover a mount point */
#define MNT_EMPTYDIR    0x0000002000000000ULL /* Only mount on empty dir */
#define MNT_RECURSE     0x0000100000000000ULL /* recursively unmount uppers */
#define MNT_DEFERRED    0x0000200000000000ULL /* unmount in async context */
#define MNT_CMDFLAGS   (MNT_UPDATE      | MNT_DELEXPORT | MNT_RELOAD    | \
                        MNT_FORCE       | MNT_SNAPSHOT  | MNT_NONBUSY   | \
                        MNT_BYFSID      | MNT_NOCOVER   | MNT_EMPTYDIR  | \
                        MNT_RECURSE     | MNT_DEFERRED)

/*
 * Internal filesystem control flags stored in mnt_kern_flag.
 *
 * MNTK_UNMOUNT locks the mount entry so that name lookup cannot
 * proceed past the mount point.  This keeps the subtree stable during
 * mounts and unmounts.  When non-forced unmount flushes all vnodes
 * from the mp queue, the MNTK_UNMOUNT flag prevents insmntque() from
 * queueing new vnodes.
 *
 * MNTK_UNMOUNTF permits filesystems to detect a forced unmount while
 * dounmount() is still waiting to lock the mountpoint. This allows
 * the filesystem to cancel operations that might otherwise deadlock
 * with the unmount attempt (used by NFS).
 */
#define MNTK_UNMOUNTF           0x00000001 /* forced unmount in progress */
#define MNTK_ASYNC              0x00000002 /* filtered async flag */
#define MNTK_SOFTDEP            0x00000004 /* async disabled by softdep */
#define MNTK_NOMSYNC            0x00000008 /* don't do msync */
#define MNTK_DRAINING           0x00000010 /* lock draining is happening */
#define MNTK_REFEXPIRE          0x00000020 /* refcount expiring is happening */
#define MNTK_EXTENDED_SHARED    0x00000040 /* Allow shared locking for more ops */
#define MNTK_SHARED_WRITES      0x00000080 /* Allow shared locking for writes */
#define MNTK_NO_IOPF            0x00000100 /* Disallow page faults during reads
                                              and writes. Filesystem shall
                                              properly handle i/o state on
                                              EFAULT. */
#define MNTK_RECURSE            0x00000200 /* pending recursive unmount */
#define MNTK_UPPER_WAITER       0x00000400 /* waiting to drain MNTK_UPPER_PENDING */
/* UNUSED                       0x00000800 */
#define MNTK_UNLOCKED_INSMNTQUE 0x00001000 /* fs does not lock the vnode for
                                              insmntque */
#define MNTK_UNMAPPED_BUFS      0x00002000
#define MNTK_USES_BCACHE        0x00004000 /* FS uses the buffer cache. */
/* UNUSED                       0x00008000 */
#define MNTK_VMSETSIZE_BUG      0x00010000
#define MNTK_UNIONFS            0x00020000 /* A hack for F_ISUNIONSTACK */
#define MNTK_FPLOOKUP           0x00040000 /* fast path lookup is supported */
#define MNTK_SUSPEND_ALL        0x00080000 /* Suspended by all-fs suspension */
#define MNTK_TASKQUEUE_WAITER   0x00100000 /* Waiting on unmount taskqueue */
/* UNUSED                       0x00200000 */
/* UNUSED                       0x00400000 */
#define MNTK_NOASYNC            0x00800000 /* disable async */
#define MNTK_UNMOUNT            0x01000000 /* unmount in progress */
#define MNTK_MWAIT              0x02000000 /* waiting for unmount to finish */
#define MNTK_SUSPEND            0x08000000 /* request write suspension */
#define MNTK_SUSPEND2           0x04000000 /* block secondary writes */
#define MNTK_SUSPENDED          0x10000000 /* write operations are suspended */
#define MNTK_NULL_NOCACHE       0x20000000 /* auto disable cache for nullfs
                                              mounts over this fs */
#define MNTK_LOOKUP_SHARED      0x40000000 /* FS supports shared lock lookups */
/* UNUSED                       0x80000000 */

#ifdef _KERNEL
static inline int
MNT_SHARED_WRITES(struct mount *mp)
{

        return (mp != NULL && (mp->mnt_kern_flag & MNTK_SHARED_WRITES) != 0);
}

static inline int
MNT_EXTENDED_SHARED(struct mount *mp)
{

        return (mp != NULL && (mp->mnt_kern_flag & MNTK_EXTENDED_SHARED) != 0);
}
#endif

/*
 * Sysctl CTL_VFS definitions.
 *
 * Second level identifier specifies which filesystem. Second level
 * identifier VFS_VFSCONF returns information about all filesystems.
 * Second level identifier VFS_GENERIC is non-terminal.
 */
#define VFS_VFSCONF             0       /* get configured filesystems */
#define VFS_GENERIC             0       /* generic filesystem information */
/*
 * Third level identifiers for VFS_GENERIC are given below; third
 * level identifiers for specific filesystems are given in their
 * mount specific header files.
 */
#define VFS_MAXTYPENUM  1       /* int: highest defined filesystem type */
#define VFS_CONF        2       /* struct: vfsconf for filesystem given
                                   as next argument */

/*
 * Flags for various system call interfaces.
 *
 * waitfor flags to vfs_sync() and getfsstat()
 */
#define MNT_WAIT        1       /* synchronously wait for I/O to complete */
#define MNT_NOWAIT      2       /* start all I/O, but do not wait for it */
#define MNT_LAZY        3       /* push data not written by filesystem syncer */
#define MNT_SUSPEND     4       /* Suspend file system after sync */

/*
 * Generic file handle
 */
struct fhandle {
        fsid_t  fh_fsid;        /* Filesystem id of mount point */
        struct  fid fh_fid;     /* Filesys specific id */
};
typedef struct fhandle  fhandle_t;

/*
 * Old export arguments without security flavor list
 */
struct oexport_args {
        int     ex_flags;               /* export related flags */
        uid_t   ex_root;                /* mapping for root uid */
        struct  xucred ex_anon;         /* mapping for anonymous user */
        struct  sockaddr *ex_addr;      /* net address to which exported */
        u_char  ex_addrlen;             /* and the net address length */
        struct  sockaddr *ex_mask;      /* mask of valid bits in saddr */
        u_char  ex_masklen;             /* and the smask length */
        char    *ex_indexfile;          /* index file for WebNFS URLs */
};

/*
 * Not quite so old export arguments with 32bit ex_flags and xucred ex_anon.
 */
#define MAXSECFLAVORS   5
struct o2export_args {
        int     ex_flags;               /* export related flags */
        uid_t   ex_root;                /* mapping for root uid */
        struct  xucred ex_anon;         /* mapping for anonymous user */
        struct  sockaddr *ex_addr;      /* net address to which exported */
        u_char  ex_addrlen;             /* and the net address length */
        struct  sockaddr *ex_mask;      /* mask of valid bits in saddr */
        u_char  ex_masklen;             /* and the smask length */
        char    *ex_indexfile;          /* index file for WebNFS URLs */
        int     ex_numsecflavors;       /* security flavor count */
        int     ex_secflavors[MAXSECFLAVORS]; /* list of security flavors */
};

/*
 * Export arguments for local filesystem mount calls.
 */
struct export_args {
        uint64_t ex_flags;              /* export related flags */
        uid_t   ex_root;                /* mapping for root uid */
        uid_t   ex_uid;                 /* mapping for anonymous user */
        int     ex_ngroups;
        gid_t   *ex_groups;
        struct  sockaddr *ex_addr;      /* net address to which exported */
        u_char  ex_addrlen;             /* and the net address length */
        struct  sockaddr *ex_mask;      /* mask of valid bits in saddr */
        u_char  ex_masklen;             /* and the smask length */
        char    *ex_indexfile;          /* index file for WebNFS URLs */
        int     ex_numsecflavors;       /* security flavor count */
        int     ex_secflavors[MAXSECFLAVORS]; /* list of security flavors */
};

/*
 * Structure holding information for a publicly exported filesystem
 * (WebNFS). Currently the specs allow just for one such filesystem.
 */
struct nfs_public {
        int             np_valid;       /* Do we hold valid information */
        fhandle_t       np_handle;      /* Filehandle for pub fs (internal) */
        struct mount    *np_mount;      /* Mountpoint of exported fs */
        char            *np_index;      /* Index file */
};

/*
 * Filesystem configuration information. One of these exists for each
 * type of filesystem supported by the kernel. These are searched at
 * mount time to identify the requested filesystem.
 *
 * XXX: Never change the first two arguments!
 */
struct vfsconf {
        u_int   vfc_version;            /* ABI version number */
        char    vfc_name[MFSNAMELEN];   /* filesystem type name */
        struct  vfsops *vfc_vfsops;     /* filesystem operations vector */
        struct  vfsops *vfc_vfsops_sd;  /* ... signal-deferred */
        int     vfc_typenum;            /* historic filesystem type number */
        int     vfc_refcount;           /* number mounted of this type */
        int     vfc_flags;              /* permanent flags */
        int     vfc_prison_flag;        /* prison allow.mount.* flag */
        struct  vfsoptdecl *vfc_opts;   /* mount options */
        TAILQ_ENTRY(vfsconf) vfc_list;  /* list of vfscons */
};

/* Userland version of the struct vfsconf. */
struct xvfsconf {
        struct  vfsops *vfc_vfsops;     /* filesystem operations vector */
        char    vfc_name[MFSNAMELEN];   /* filesystem type name */
        int     vfc_typenum;            /* historic filesystem type number */
        int     vfc_refcount;           /* number mounted of this type */
        int     vfc_flags;              /* permanent flags */
        struct  vfsconf *vfc_next;      /* next in list */
};

#ifndef BURN_BRIDGES
struct ovfsconf {
        void    *vfc_vfsops;
        char    vfc_name[32];
        int     vfc_index;
        int     vfc_refcount;
        int     vfc_flags;
};
#endif

/*
 * NB: these flags refer to IMPLEMENTATION properties, not properties of
 * any actual mounts; i.e., it does not make sense to change the flags.
 */
#define VFCF_STATIC     0x00010000      /* statically compiled into kernel */
#define VFCF_NETWORK    0x00020000      /* may get data over the network */
#define VFCF_READONLY   0x00040000      /* writes are not implemented */
#define VFCF_SYNTHETIC  0x00080000      /* data does not represent real files */
#define VFCF_LOOPBACK   0x00100000      /* aliases some other mounted FS */
#define VFCF_UNICODE    0x00200000      /* stores file names as Unicode */
#define VFCF_JAIL       0x00400000      /* can be mounted from within a jail */
#define VFCF_DELEGADMIN 0x00800000      /* supports delegated administration */
#define VFCF_SBDRY      0x01000000      /* Stop at Boundary: defer stop requests
                                           to kernel->user (AST) transition */
#define VFCF_FILEMOUNT  0x02000000      /* allow mounting files */
#define VFCF_FILEREVINC 0x04000000      /* va_filerev is incr. by one */
#define VFCF_FILEREVCT  0x08000000      /* va_filerev is set to ctime */

typedef uint32_t fsctlop_t;

struct vfsidctl {
        int             vc_vers;        /* should be VFSIDCTL_VERS1 (below) */
        fsid_t          vc_fsid;        /* fsid to operate on */
        char            vc_fstypename[MFSNAMELEN];
                                        /* type of fs 'nfs' or '*' */
        fsctlop_t       vc_op;          /* operation VFS_CTL_* (below) */
        void            *vc_ptr;        /* pointer to data structure */
        size_t          vc_len;         /* sizeof said structure */
        u_int32_t       vc_spare[12];   /* spare (must be zero) */
};

/* vfsidctl API version. */
#define VFS_CTL_VERS1   0x01

/*
 * New style VFS sysctls, do not reuse/conflict with the namespace for
 * private sysctls.
 * All "global" sysctl ops have the 33rd bit set:
 * 0x...1....
 * Private sysctl ops should have the 33rd bit unset.
 */
#define VFS_CTL_QUERY   0x00010001      /* anything wrong? (vfsquery) */
#define VFS_CTL_TIMEO   0x00010002      /* set timeout for vfs notification */
#define VFS_CTL_NOLOCKS 0x00010003      /* disable file locking */

struct vfsquery {
        u_int32_t       vq_flags;
        u_int32_t       vq_spare[31];
};

/* vfsquery flags */
#define VQ_NOTRESP      0x0001  /* server down */
#define VQ_NEEDAUTH     0x0002  /* server bad auth */
#define VQ_LOWDISK      0x0004  /* we're low on space */
#define VQ_MOUNT        0x0008  /* new filesystem arrived */
#define VQ_UNMOUNT      0x0010  /* filesystem has left */
#define VQ_DEAD         0x0020  /* filesystem is dead, needs force unmount */
#define VQ_ASSIST       0x0040  /* filesystem needs assistance from external
                                   program */
#define VQ_NOTRESPLOCK  0x0080  /* server lockd down */
#define VQ_FLAG0100     0x0100  /* placeholder */
#define VQ_FLAG0200     0x0200  /* placeholder */
#define VQ_FLAG0400     0x0400  /* placeholder */
#define VQ_FLAG0800     0x0800  /* placeholder */
#define VQ_FLAG1000     0x1000  /* placeholder */
#define VQ_FLAG2000     0x2000  /* placeholder */
#define VQ_FLAG4000     0x4000  /* placeholder */
#define VQ_FLAG8000     0x8000  /* placeholder */

#ifdef _KERNEL
/* Point a sysctl request at a vfsidctl's data. */
#define VCTLTOREQ(vc, req)                                              \
        do {                                                            \
                (req)->newptr = (vc)->vc_ptr;                           \
                (req)->newlen = (vc)->vc_len;                           \
                (req)->newidx = 0;                                      \
        } while (0)
#endif

struct iovec;
struct uio;

#ifdef _KERNEL

/*
 * vfs_busy specific flags and mask.
 */
#define MBF_NOWAIT      0x01
#define MBF_MNTLSTLOCK  0x02
#define MBF_MASK        (MBF_NOWAIT | MBF_MNTLSTLOCK)

#ifdef MALLOC_DECLARE
MALLOC_DECLARE(M_MOUNT);
MALLOC_DECLARE(M_STATFS);
#endif
extern int maxvfsconf;          /* highest defined filesystem type */

TAILQ_HEAD(vfsconfhead, vfsconf);
extern struct vfsconfhead vfsconf;

/*
 * Operations supported on mounted filesystem.
 */
struct mount_args;
struct nameidata;
struct sysctl_req;
struct mntarg;

/*
 * N.B., vfs_cmount is the ancient vfsop invoked by the old mount(2) syscall.
 * The new way is vfs_mount.
 *
 * vfs_cmount implementations typically translate arguments from their
 * respective old per-FS structures into the key-value list supported by
 * nmount(2), then use kernel_mount(9) to mimic nmount(2) from kernelspace.
 *
 * Filesystems with mounters that use nmount(2) do not need to and should not
 * implement vfs_cmount.  Hopefully a future cleanup can remove vfs_cmount and
 * mount(2) entirely.
 */
typedef int vfs_cmount_t(struct mntarg *ma, void *data, uint64_t flags);
typedef int vfs_unmount_t(struct mount *mp, int mntflags);
typedef int vfs_root_t(struct mount *mp, int flags, struct vnode **vpp);
typedef int vfs_quotactl_t(struct mount *mp, int cmds, uid_t uid, void *arg,
                    bool *mp_busy);
typedef int vfs_statfs_t(struct mount *mp, struct statfs *sbp);
typedef int vfs_sync_t(struct mount *mp, int waitfor);
typedef int vfs_vget_t(struct mount *mp, ino_t ino, int flags,
                    struct vnode **vpp);
typedef int vfs_fhtovp_t(struct mount *mp, struct fid *fhp,
                    int flags, struct vnode **vpp);
typedef int vfs_checkexp_t(struct mount *mp, struct sockaddr *nam,
                    uint64_t *extflagsp, struct ucred **credanonp,
                    int *numsecflavors, int *secflavors);
typedef int vfs_init_t(struct vfsconf *);
typedef int vfs_uninit_t(struct vfsconf *);
typedef int vfs_extattrctl_t(struct mount *mp, int cmd,
                    struct vnode *filename_vp, int attrnamespace,
                    const char *attrname);
typedef int vfs_mount_t(struct mount *mp);
typedef int vfs_sysctl_t(struct mount *mp, fsctlop_t op,
                    struct sysctl_req *req);
typedef void vfs_susp_clean_t(struct mount *mp);
typedef void vfs_notify_lowervp_t(struct mount *mp, struct vnode *lowervp);
typedef void vfs_purge_t(struct mount *mp);
struct sbuf;
typedef int vfs_report_lockf_t(struct mount *mp, struct sbuf *sb);

struct vfsops {
        vfs_mount_t             *vfs_mount;
        vfs_cmount_t            *vfs_cmount;
        vfs_unmount_t           *vfs_unmount;
        vfs_root_t              *vfs_root;
        vfs_root_t              *vfs_cachedroot;
        vfs_quotactl_t          *vfs_quotactl;
        vfs_statfs_t            *vfs_statfs;
        vfs_sync_t              *vfs_sync;
        vfs_vget_t              *vfs_vget;
        vfs_fhtovp_t            *vfs_fhtovp;
        vfs_checkexp_t          *vfs_checkexp;
        vfs_init_t              *vfs_init;
        vfs_uninit_t            *vfs_uninit;
        vfs_extattrctl_t        *vfs_extattrctl;
        vfs_sysctl_t            *vfs_sysctl;
        vfs_susp_clean_t        *vfs_susp_clean;
        vfs_notify_lowervp_t    *vfs_reclaim_lowervp;
        vfs_notify_lowervp_t    *vfs_unlink_lowervp;
        vfs_purge_t             *vfs_purge;
        vfs_report_lockf_t      *vfs_report_lockf;
        vfs_mount_t             *vfs_spare[6];  /* spares for ABI compat */
};

vfs_statfs_t    __vfs_statfs;

#define VFS_MOUNT(MP) ({                                                \
        int _rc;                                                        \
                                                                        \
        TSRAW(curthread, TS_ENTER, "VFS_MOUNT", (MP)->mnt_vfc->vfc_name);\
        _rc = (*(MP)->mnt_op->vfs_mount)(MP);                           \
        TSRAW(curthread, TS_EXIT, "VFS_MOUNT", (MP)->mnt_vfc->vfc_name);\
        _rc; })

#define VFS_UNMOUNT(MP, FORCE) ({                                       \
        int _rc;                                                        \
                                                                        \
        _rc = (*(MP)->mnt_op->vfs_unmount)(MP, FORCE);                  \
        _rc; })

#define VFS_ROOT(MP, FLAGS, VPP) ({                                     \
        int _rc;                                                        \
                                                                        \
        _rc = (*(MP)->mnt_op->vfs_root)(MP, FLAGS, VPP);                \
        _rc; })

#define VFS_CACHEDROOT(MP, FLAGS, VPP) ({                               \
        int _rc;                                                        \
                                                                        \
        _rc = (*(MP)->mnt_op->vfs_cachedroot)(MP, FLAGS, VPP);          \
        _rc; })

#define VFS_QUOTACTL(MP, C, U, A, MP_BUSY) ({                           \
        int _rc;                                                        \
                                                                        \
        _rc = (*(MP)->mnt_op->vfs_quotactl)(MP, C, U, A, MP_BUSY);      \
        _rc; })

#define VFS_STATFS(MP, SBP) ({                                          \
        int _rc;                                                        \
                                                                        \
        _rc = __vfs_statfs((MP), (SBP));                                \
        _rc; })

#define VFS_SYNC(MP, WAIT) ({                                           \
        int _rc;                                                        \
                                                                        \
        _rc = (*(MP)->mnt_op->vfs_sync)(MP, WAIT);                      \
        _rc; })

#define VFS_VGET(MP, INO, FLAGS, VPP) ({                                \
        int _rc;                                                        \
                                                                        \
        _rc = (*(MP)->mnt_op->vfs_vget)(MP, INO, FLAGS, VPP);           \
        _rc; })

#define VFS_FHTOVP(MP, FIDP, FLAGS, VPP) ({                             \
        int _rc;                                                        \
                                                                        \
        _rc = (*(MP)->mnt_op->vfs_fhtovp)(MP, FIDP, FLAGS, VPP);        \
        _rc; })

#define VFS_CHECKEXP(MP, NAM, EXFLG, CRED, NUMSEC, SEC) ({              \
        int _rc;                                                        \
                                                                        \
        _rc = (*(MP)->mnt_op->vfs_checkexp)(MP, NAM, EXFLG, CRED, NUMSEC,\
            SEC);                                                       \
        _rc; })

#define VFS_EXTATTRCTL(MP, C, FN, NS, N) ({                             \
        int _rc;                                                        \
                                                                        \
        _rc = (*(MP)->mnt_op->vfs_extattrctl)(MP, C, FN, NS, N);        \
        _rc; })

#define VFS_SYSCTL(MP, OP, REQ) ({                                      \
        int _rc;                                                        \
                                                                        \
        _rc = (*(MP)->mnt_op->vfs_sysctl)(MP, OP, REQ);                 \
        _rc; })

#define VFS_SUSP_CLEAN(MP) do {                                         \
        if (*(MP)->mnt_op->vfs_susp_clean != NULL) {                    \
                (*(MP)->mnt_op->vfs_susp_clean)(MP);                    \
        }                                                               \
} while (0)

#define VFS_RECLAIM_LOWERVP(MP, VP) do {                                \
        if (*(MP)->mnt_op->vfs_reclaim_lowervp != NULL) {               \
                (*(MP)->mnt_op->vfs_reclaim_lowervp)((MP), (VP));       \
        }                                                               \
} while (0)

#define VFS_UNLINK_LOWERVP(MP, VP) do {                                 \
        if (*(MP)->mnt_op->vfs_unlink_lowervp != NULL) {                \
                (*(MP)->mnt_op->vfs_unlink_lowervp)((MP), (VP));        \
        }                                                               \
} while (0)

#define VFS_PURGE(MP) do {                                              \
        if (*(MP)->mnt_op->vfs_purge != NULL) {                         \
                (*(MP)->mnt_op->vfs_purge)(MP);                         \
        }                                                               \
} while (0)

#define VFS_KNOTE_LOCKED(vp, hint) do                                   \
{                                                                       \
        VN_KNOTE((vp), (hint), KNF_LISTLOCKED);                         \
} while (0)

#define VFS_KNOTE_UNLOCKED(vp, hint) do                                 \
{                                                                       \
        VN_KNOTE((vp), (hint), 0);                                      \
} while (0)

#include <sys/module.h>

/*
 * Version numbers.
 */
#define VFS_VERSION_00  0x19660120
#define VFS_VERSION_01  0x20121030
#define VFS_VERSION_02  0x20180504
#define VFS_VERSION     VFS_VERSION_02

#define VFS_SET(vfsops, fsname, flags) \
        static struct vfsconf fsname ## _vfsconf = {            \
                .vfc_version = VFS_VERSION,                     \
                .vfc_name = #fsname,                            \
                .vfc_vfsops = &vfsops,                          \
                .vfc_typenum = -1,                              \
                .vfc_flags = flags,                             \
        };                                                      \
        static moduledata_t fsname ## _mod = {                  \
                #fsname,                                        \
                vfs_modevent,                                   \
                & fsname ## _vfsconf                            \
        };                                                      \
        DECLARE_MODULE(fsname, fsname ## _mod, SI_SUB_VFS, SI_ORDER_MIDDLE)

enum vfs_notify_upper_type {
        VFS_NOTIFY_UPPER_RECLAIM,
        VFS_NOTIFY_UPPER_UNLINK,
};

/*
 * exported vnode operations
 */

/* Define this to indicate that vfs_exjail_clone() exists for ZFS to use. */
#define VFS_SUPPORTS_EXJAIL_CLONE       1

int     dounmount(struct mount *, uint64_t, struct thread *);

int     kernel_mount(struct mntarg *ma, uint64_t flags);
struct mntarg *mount_arg(struct mntarg *ma, const char *name, const void *val, int len);
struct mntarg *mount_argb(struct mntarg *ma, int flag, const char *name);
struct mntarg *mount_argf(struct mntarg *ma, const char *name, const char *fmt, ...);
struct mntarg *mount_argsu(struct mntarg *ma, const char *name, const void *val, int len);
void    statfs_scale_blocks(struct statfs *sf, long max_size);
struct vfsconf *vfs_byname(const char *);
struct vfsconf *vfs_byname_kld(const char *, struct thread *td, int *);
void    vfs_unref_vfsconf(struct vfsconf *vfsp);
void    vfs_mount_destroy(struct mount *);
void    vfs_event_signal(fsid_t *, u_int32_t, intptr_t);
void    vfs_freeopts(struct vfsoptlist *opts);
void    vfs_deleteopt(struct vfsoptlist *opts, const char *name);
int     vfs_buildopts(struct uio *auio, struct vfsoptlist **options);
int     vfs_flagopt(struct vfsoptlist *opts, const char *name, uint64_t *w,
            uint64_t val);
int     vfs_getopt(struct vfsoptlist *, const char *, void **, int *);
int     vfs_getopt_pos(struct vfsoptlist *opts, const char *name);
int     vfs_getopt_size(struct vfsoptlist *opts, const char *name,
            off_t *value);
char    *vfs_getopts(struct vfsoptlist *, const char *, int *error);
int     vfs_copyopt(struct vfsoptlist *, const char *, void *, int);
int     vfs_filteropt(struct vfsoptlist *, const char **legal);
void    vfs_opterror(struct vfsoptlist *opts, const char *fmt, ...);
int     vfs_scanopt(struct vfsoptlist *opts, const char *name, const char *fmt, ...);
int     vfs_setopt(struct vfsoptlist *opts, const char *name, void *value,
            int len);
int     vfs_setopt_part(struct vfsoptlist *opts, const char *name, void *value,
            int len);
int     vfs_setopts(struct vfsoptlist *opts, const char *name,
            const char *value);
int     vfs_setpublicfs                     /* set publicly exported fs */
            (struct mount *, struct netexport *, struct export_args *);
void    vfs_periodic(struct mount *, int);
int     vfs_busy(struct mount *, int);
void    vfs_exjail_clone(struct mount *, struct mount *);
void    vfs_exjail_delete(struct prison *);
int     vfs_export                       /* process mount export info */
            (struct mount *, struct export_args *, bool);
void    vfs_free_addrlist(struct netexport *);
void    vfs_allocate_syncvnode(struct mount *);
void    vfs_deallocate_syncvnode(struct mount *);
int     vfs_donmount(struct thread *td, uint64_t fsflags,
            struct uio *fsoptions);
void    vfs_getnewfsid(struct mount *);
struct  mount *vfs_getvfs(fsid_t *);      /* return vfs given fsid */
struct  mount *vfs_busyfs(fsid_t *);
int     vfs_modevent(module_t, int, void *);
void    vfs_mount_error(struct mount *, const char *, ...);
void    vfs_mountroot(void);                    /* mount our root filesystem */
void    vfs_mountedfrom(struct mount *, const char *from);
void    vfs_notify_upper(struct vnode *, enum vfs_notify_upper_type);
struct mount *vfs_ref_from_vp(struct vnode *);
void    vfs_ref(struct mount *);
void    vfs_rel(struct mount *);
struct mount *vfs_mount_alloc(struct vnode *, struct vfsconf *, const char *,
            struct ucred *);
int     vfs_suser(struct mount *, struct thread *);
void    vfs_unbusy(struct mount *);
void    vfs_unmountall(void);
struct mount *vfs_register_upper_from_vp(struct vnode *,
            struct mount *ump, struct mount_upper_node *);
void    vfs_register_for_notification(struct mount *, struct mount *,
            struct mount_upper_node *);
void    vfs_unregister_for_notification(struct mount *,
            struct mount_upper_node *);
void    vfs_unregister_upper(struct mount *, struct mount_upper_node *);
int     vfs_remount_ro(struct mount *mp);
int     vfs_report_lockf(struct mount *mp, struct sbuf *sb);

extern  TAILQ_HEAD(mntlist, mount) mountlist;   /* mounted filesystem list */
extern  struct mtx_padalign mountlist_mtx;
extern  struct nfs_public nfs_pub;
extern  struct sx vfsconf_sx;
#define vfsconf_lock()          sx_xlock(&vfsconf_sx)
#define vfsconf_unlock()        sx_xunlock(&vfsconf_sx)
#define vfsconf_slock()         sx_slock(&vfsconf_sx)
#define vfsconf_sunlock()       sx_sunlock(&vfsconf_sx)
struct vnode *mntfs_allocvp(struct mount *, struct vnode *);
void   mntfs_freevp(struct vnode *);

/*
 * Declarations for these vfs default operations are located in
 * kern/vfs_default.c.  They will be automatically used to replace
 * null entries in VFS ops tables when registering a new filesystem
 * type in the global table.
 */
vfs_root_t              vfs_stdroot;
vfs_quotactl_t          vfs_stdquotactl;
vfs_statfs_t            vfs_stdstatfs;
vfs_sync_t              vfs_stdsync;
vfs_sync_t              vfs_stdnosync;
vfs_vget_t              vfs_stdvget;
vfs_fhtovp_t            vfs_stdfhtovp;
vfs_checkexp_t          vfs_stdcheckexp;
vfs_init_t              vfs_stdinit;
vfs_uninit_t            vfs_stduninit;
vfs_extattrctl_t        vfs_stdextattrctl;
vfs_sysctl_t            vfs_stdsysctl;

void    syncer_suspend(void);
void    syncer_resume(void);

struct vnode *vfs_cache_root_clear(struct mount *);
void    vfs_cache_root_set(struct mount *, struct vnode *);

void    vfs_op_barrier_wait(struct mount *);
void    vfs_op_enter(struct mount *);
void    vfs_op_exit_locked(struct mount *);
void    vfs_op_exit(struct mount *);

#ifdef DIAGNOSTIC
void    vfs_assert_mount_counters(struct mount *);
void    vfs_dump_mount_counters(struct mount *);
#else
#define vfs_assert_mount_counters(mp) do { } while (0)
#define vfs_dump_mount_counters(mp) do { } while (0)
#endif

enum mount_counter { MNT_COUNT_REF, MNT_COUNT_LOCKREF, MNT_COUNT_WRITEOPCOUNT };
int     vfs_mount_fetch_counter(struct mount *, enum mount_counter);

void suspend_all_fs(void);
void resume_all_fs(void);

/*
 * Code transitioning mnt_vfs_ops to > 0 issues IPIs until it observes
 * all CPUs not executing code enclosed by thread_in_ops_pcpu variable.
 *
 * This provides an invariant that by the time the last CPU is observed not
 * executing, everyone else entering will see the counter > 0 and exit.
 *
 * Note there is no barrier between vfs_ops and the rest of the code in the
 * section. It is not necessary as the writer has to wait for everyone to drain
 * before making any changes or only make changes safe while the section is
 * executed.
 */
#define vfs_mount_pcpu(mp)              zpcpu_get(mp->mnt_pcpu)
#define vfs_mount_pcpu_remote(mp, cpu)  zpcpu_get_cpu(mp->mnt_pcpu, cpu)

#define vfs_op_thread_entered(mp) ({                            \
        MPASS(curthread->td_critnest > 0);                      \
        struct mount_pcpu *_mpcpu = vfs_mount_pcpu(mp);         \
        _mpcpu->mntp_thread_in_ops == 1;                        \
})

#define vfs_op_thread_enter_crit(mp, _mpcpu) ({                 \
        bool _retval_crit = true;                               \
        MPASS(curthread->td_critnest > 0);                      \
        _mpcpu = vfs_mount_pcpu(mp);                            \
        MPASS(mpcpu->mntp_thread_in_ops == 0);                  \
        _mpcpu->mntp_thread_in_ops = 1;                         \
        atomic_interrupt_fence();                                       \
        if (__predict_false(mp->mnt_vfs_ops > 0)) {             \
                vfs_op_thread_exit_crit(mp, _mpcpu);            \
                _retval_crit = false;                           \
        }                                                       \
        _retval_crit;                                           \
})

#define vfs_op_thread_enter(mp, _mpcpu) ({                      \
        bool _retval;                                           \
        critical_enter();                                       \
        _retval = vfs_op_thread_enter_crit(mp, _mpcpu);         \
        if (__predict_false(!_retval))                          \
                critical_exit();                                \
        _retval;                                                \
})

#define vfs_op_thread_exit_crit(mp, _mpcpu) do {                \
        MPASS(_mpcpu == vfs_mount_pcpu(mp));                    \
        MPASS(_mpcpu->mntp_thread_in_ops == 1);                 \
        atomic_interrupt_fence();                                       \
        _mpcpu->mntp_thread_in_ops = 0;                         \
} while (0)

#define vfs_op_thread_exit(mp, _mpcpu) do {                     \
        vfs_op_thread_exit_crit(mp, _mpcpu);                    \
        critical_exit();                                        \
} while (0)

#define vfs_mp_count_add_pcpu(_mpcpu, count, val) do {          \
        MPASS(_mpcpu->mntp_thread_in_ops == 1);                 \
        _mpcpu->mntp_##count += val;                            \
} while (0)

#define vfs_mp_count_sub_pcpu(_mpcpu, count, val) do {          \
        MPASS(_mpcpu->mntp_thread_in_ops == 1);                 \
        _mpcpu->mntp_##count -= val;                            \
} while (0)

#else /* !_KERNEL */

#include <sys/cdefs.h>

struct stat;

__BEGIN_DECLS
int     fhlink(struct fhandle *, const char *);
int     fhlinkat(struct fhandle *, int, const char *);
int     fhopen(const struct fhandle *, int);
int     fhreadlink(struct fhandle *, char *, size_t);
int     fhstat(const struct fhandle *, struct stat *);
int     fhstatfs(const struct fhandle *, struct statfs *);
int     fstatfs(int, struct statfs *);
int     getfh(const char *, fhandle_t *);
int     getfhat(int, char *, struct fhandle *, int);
int     getfsstat(struct statfs *, long, int);
int     getmntinfo(struct statfs **, int);
int     lgetfh(const char *, fhandle_t *);
int     mount(const char *, const char *, int, void *);
int     nmount(struct iovec *, unsigned int, int);
int     statfs(const char *, struct statfs *);
int     unmount(const char *, int);

/* C library stuff */
int     getvfsbyname(const char *, struct xvfsconf *);
__END_DECLS

#endif /* _KERNEL */

#endif /* !_SYS_MOUNT_H_ */