text: /*-
   * 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.
   * 4. 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.
   *
   *	@(#)mount.h	8.21 (Berkeley) 5/20/95
   * $FreeBSD: src/sys/sys/mount.h,v 1.249.2.4.2.1 2010/12/21 17:09:25 kensmith Exp $
   */
  
  #ifndef _SYS_MOUNT_H_
  #define _SYS_MOUNT_H_
  
  #include <sys/ucred.h>
  #include <sys/queue.h>
  #ifdef _KERNEL
  #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 */
  
  /*
   * File identifier.
   * These are unique per filesystem on a single machine.
   */
  #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	88		/* size of on/from name bufs */
  #define	STATFS_VERSION	0x20030518	/* 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 */
  	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[MFSNAMELEN]; /* filesystem type name */
  	char	  f_mntfromname[MNAMELEN];  /* mounted filesystem */
  	char	  f_mntonname[MNAMELEN];    /* directory on which mounted */
  };
  
  #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 */
  };
  
  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;
  };
  
  /*
   * 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:
   *	m - mountlist_mtx
   *	i - interlock
   *
   * Unmarked fields are considered stable as long as a ref is held.
   *
   */
  struct mount {
  	struct mtx	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 vfsops	*mnt_op;		/* operations on fs */
  	struct vfsconf	*mnt_vfc;		/* configuration info */
  	struct vnode	*mnt_vnodecovered;	/* vnode we mounted on */
  	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 */
  	int		mnt_kern_flag;		/* (i) kernel only flags */
  	u_int		mnt_flag;		/* (i) flags shared with user */
  	u_int		mnt_xflag;		/* (i) more flags shared with user */
  	u_int		mnt_noasync;		/* (i) # noasync overrides */
  	struct vfsoptlist *mnt_opt;		/* current mount options */
  	struct vfsoptlist *mnt_optnew;		/* new options passed to fs */
  	int		mnt_maxsymlinklen;	/* max size of short symlink */
  	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;		/* 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 */
  #define	mnt_endzero	mnt_gjprovider
  	char		*mnt_gjprovider;	/* gjournal provider name */
  	struct lock	mnt_explock;		/* vfs_export walkers lock */
  };
  
  struct vnode *__mnt_vnode_next(struct vnode **mvp, struct mount *mp);
  struct vnode *__mnt_vnode_first(struct vnode **mvp, struct mount *mp);
  void          __mnt_vnode_markerfree(struct vnode **mvp, struct mount *mp);
  
  #define MNT_VNODE_FOREACH(vp, mp, mvp) \
  	for (vp = __mnt_vnode_first(&(mvp), (mp)); \
  		(vp) != NULL; vp = __mnt_vnode_next(&(mvp), (mp)))
  
  #define MNT_VNODE_FOREACH_ABORT_ILOCKED(mp, mvp)			\
  	__mnt_vnode_markerfree(&(mvp), (mp))
  
  #define MNT_VNODE_FOREACH_ABORT(mp, mvp)				\
          do {								\
  	  MNT_ILOCK(mp);						\
            MNT_VNODE_FOREACH_ABORT_ILOCKED(mp, mvp);			\
  	  MNT_IUNLOCK(mp);						\
  	} while (0)
  
  #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)	(mp)->mnt_ref++
  #define	MNT_REL(mp)	do {						\
  	KASSERT((mp)->mnt_ref > 0, ("negative mnt_ref"));			\
  	(mp)->mnt_ref--;						\
  	if ((mp)->mnt_ref == 0)						\
  		wakeup((mp));						\
  } while (0)
  
  #endif /* _KERNEL */
  
  /*
   * User specifiable flags, stored in mnt_flag.
   */
  #define	MNT_RDONLY	0x00000001	/* read only filesystem */
  #define	MNT_SYNCHRONOUS	0x00000002	/* filesystem written synchronously */
  #define	MNT_NOEXEC	0x00000004	/* can't exec from filesystem */
  #define	MNT_NOSUID	0x00000008	/* don't honor setuid bits on fs */
  #define	MNT_UNION	0x00000020	/* union with underlying filesystem */
  #define	MNT_ASYNC	0x00000040	/* filesystem written asynchronously */
  #define	MNT_SUIDDIR	0x00100000	/* special handling of SUID on dirs */
  #define	MNT_SOFTDEP	0x00200000	/* soft updates being done */
  #define	MNT_NOSYMFOLLOW	0x00400000	/* do not follow symlinks */
  #define	MNT_GJOURNAL	0x02000000	/* GEOM journal support enabled */
  #define	MNT_MULTILABEL	0x04000000	/* MAC support for individual objects */
  #define	MNT_ACLS	0x08000000	/* ACL support enabled */
  #define	MNT_NOATIME	0x10000000	/* disable update of file access time */
  #define	MNT_NOCLUSTERR	0x40000000	/* disable cluster read */
  #define	MNT_NOCLUSTERW	0x80000000	/* disable cluster write */
  #define	MNT_NFS4ACLS	0x00000010
  
  /*
   * NFS export related mount flags.
   */
  #define	MNT_EXRDONLY	0x00000080	/* exported read only */
  #define	MNT_EXPORTED	0x00000100	/* filesystem is exported */
  #define	MNT_DEFEXPORTED	0x00000200	/* exported to the world */
  #define	MNT_EXPORTANON	0x00000400	/* use anon uid mapping for everyone */
  #define	MNT_EXKERB	0x00000800	/* exported with Kerberos uid mapping */
  #define	MNT_EXPUBLIC	0x20000000	/* public export (WebNFS) */
  
  /*
   * Flags set by internal operations,
   * but visible to the user.
   * XXX some of these are not quite right.. (I've never seen the root flag set)
   */
  #define	MNT_LOCAL	0x00001000	/* filesystem is stored locally */
  #define	MNT_QUOTA	0x00002000	/* quotas are enabled on filesystem */
  #define	MNT_ROOTFS	0x00004000	/* identifies the root filesystem */
  #define	MNT_USER	0x00008000	/* mounted by a user */
  #define	MNT_IGNORE	0x00800000	/* do not show entry in df */
  
  /*
   * 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_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)
  
  /* 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)
  
  /*
   * 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 collides with MNT_ACLS, but because MNT_ACLS is only used for
   *      mount(2) and MNT_BYFSID is only used for unmount(2) it's harmless.
   */
  #define	MNT_UPDATE	0x00010000	/* not a real mount, just an update */
  #define	MNT_DELEXPORT	0x00020000	/* delete export host lists */
  #define	MNT_RELOAD	0x00040000	/* reload filesystem data */
  #define	MNT_FORCE	0x00080000	/* force unmount or readonly change */
  #define	MNT_SNAPSHOT	0x01000000	/* snapshot the filesystem */
  #define	MNT_BYFSID	0x08000000	/* specify filesystem by ID. */
  #define MNT_CMDFLAGS   (MNT_UPDATE	| MNT_DELEXPORT	| MNT_RELOAD	| \
  			MNT_FORCE	| MNT_SNAPSHOT	| MNT_BYFSID)
  /*
   * 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.
   *
   * 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).
   *
   * MNTK_NOINSMNTQ is strict subset of MNTK_UNMOUNT. They are separated
   * to allow for failed unmount attempt to restore the syncer vnode for
   * the mount.
   */
  #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_NOINSMNTQ	0x00000008	/* insmntque is not allowed */
  #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_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_MPSAFE	0x20000000	/* Filesystem is MPSAFE. */
  #define MNTK_LOOKUP_SHARED	0x40000000 /* FS supports shared lock lookups */
  #define	MNTK_NOKNOTE	0x80000000	/* Don't send KNOTEs from VOP hooks */
  
  #define	MNT_SHARED_WRITES(mp) (((mp) != NULL) && 	\
  				((mp)->mnt_kern_flag & MNTK_SHARED_WRITES))
  
  /*
   * 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 */
  };
  
  /*
   * Export arguments for local filesystem mount calls.
   */
  #define	MAXSECFLAVORS	5
  struct export_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 */
  };
  
  /*
   * 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 */
  	int	vfc_typenum;		/* historic filesystem type number */
  	int	vfc_refcount;		/* number mounted of this type */
  	int	vfc_flags;		/* permanent flags */
  	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 */
  
  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);
  #endif
  extern int maxvfsconf;		/* highest defined filesystem type */
  extern int nfs_mount_type;	/* vfc_typenum for nfs, or -1 */
  
  TAILQ_HEAD(vfsconfhead, vfsconf);
  extern struct vfsconfhead vfsconf;
  
  /*
   * Operations supported on mounted filesystem.
   */
  struct mount_args;
  struct nameidata;
  struct sysctl_req;
  struct mntarg;
  
  typedef int vfs_cmount_t(struct mntarg *ma, void *data, int 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);
  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, struct vnode **vpp);
  typedef	int vfs_checkexp_t(struct mount *mp, struct sockaddr *nam,
  		    int *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);
  
  struct vfsops {
  	vfs_mount_t		*vfs_mount;
  	vfs_cmount_t		*vfs_cmount;
  	vfs_unmount_t		*vfs_unmount;
  	vfs_root_t		*vfs_root;
  	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_statfs_t	__vfs_statfs;
  
  #define	VFS_MOUNT(MP)		(*(MP)->mnt_op->vfs_mount)(MP)
  #define	VFS_UNMOUNT(MP, FORCE)	(*(MP)->mnt_op->vfs_unmount)(MP, FORCE)
  #define	VFS_ROOT(MP, FLAGS, VPP)					\
  	(*(MP)->mnt_op->vfs_root)(MP, FLAGS, VPP)
  #define	VFS_QUOTACTL(MP, C, U, A)					\
  	(*(MP)->mnt_op->vfs_quotactl)(MP, C, U, A)
  #define	VFS_STATFS(MP, SBP)	__vfs_statfs((MP), (SBP))
  #define	VFS_SYNC(MP, WAIT)	(*(MP)->mnt_op->vfs_sync)(MP, WAIT)
  #define VFS_VGET(MP, INO, FLAGS, VPP) \
  	(*(MP)->mnt_op->vfs_vget)(MP, INO, FLAGS, VPP)
  #define VFS_FHTOVP(MP, FIDP, VPP) \
  	(*(MP)->mnt_op->vfs_fhtovp)(MP, FIDP, VPP)
  #define VFS_CHECKEXP(MP, NAM, EXFLG, CRED, NUMSEC, SEC)	\
  	(*(MP)->mnt_op->vfs_checkexp)(MP, NAM, EXFLG, CRED, NUMSEC, SEC)
  #define	VFS_EXTATTRCTL(MP, C, FN, NS, N)				\
  	(*(MP)->mnt_op->vfs_extattrctl)(MP, C, FN, NS, N)
  #define VFS_SYSCTL(MP, OP, REQ) \
  	(*(MP)->mnt_op->vfs_sysctl)(MP, OP, REQ)
  #define	VFS_SUSP_CLEAN(MP) \
  	({if (*(MP)->mnt_op->vfs_susp_clean != NULL)		\
  	       (*(MP)->mnt_op->vfs_susp_clean)(MP); })
  
  #define	VFS_NEEDSGIANT_(MP)						\
      ((MP) != NULL && ((MP)->mnt_kern_flag & MNTK_MPSAFE) == 0)
  
  #define	VFS_NEEDSGIANT(MP) __extension__				\
  ({									\
  	struct mount *_mp;						\
  	_mp = (MP);							\
  	VFS_NEEDSGIANT_(_mp);						\
  })
  
  #define	VFS_LOCK_GIANT(MP) __extension__				\
  ({									\
  	int _locked;							\
  	struct mount *_mp;						\
  	_mp = (MP);							\
  	if (VFS_NEEDSGIANT_(_mp)) {					\
  		mtx_lock(&Giant);					\
  		_locked = 1;						\
  	} else								\
  		_locked = 0;						\
  	_locked;							\
  })
  #define	VFS_UNLOCK_GIANT(locked)	if ((locked)) mtx_unlock(&Giant);
  #define	VFS_ASSERT_GIANT(MP) do						\
  {									\
  	struct mount *_mp;						\
  	_mp = (MP);							\
  	if (VFS_NEEDSGIANT_(_mp))					\
  		mtx_assert(&Giant, MA_OWNED);				\
  } while (0)
  
  #define VFS_KNOTE_LOCKED(vp, hint) do					\
  {									\
  	if (((vp)->v_vflag & VV_NOKNOTE) == 0)				\
  		VN_KNOTE((vp), (hint), KNF_LISTLOCKED);			\
  } while (0)
  
  #define VFS_KNOTE_UNLOCKED(vp, hint) do					\
  {									\
  	if (((vp)->v_vflag & VV_NOKNOTE) == 0)				\
  		VN_KNOTE((vp), (hint), 0);				\
  } while (0)
  
  #include <sys/module.h>
  
  /*
   * Version numbers.
   */
  #define VFS_VERSION_00	0x19660120
  #define VFS_VERSION	VFS_VERSION_00
  
  #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)
  
  extern	char *mountrootfsname;
  
  /*
   * exported vnode operations
   */
  
  int	dounmount(struct mount *, int, struct thread *);
  
  int	kernel_mount(struct mntarg *ma, int flags);
  int	kernel_vmount(int 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_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, u_int *w, u_int val);
  int	vfs_getopt(struct vfsoptlist *, const char *, void **, int *);
  int	vfs_getopt_pos(struct vfsoptlist *opts, const char *name);
  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_msync(struct mount *, int);
  int	vfs_busy(struct mount *, int);
  int	vfs_export			 /* process mount export info */
  	    (struct mount *, struct export_args *);
  int	vfs_allocate_syncvnode(struct mount *);
  int	vfs_donmount(struct thread *td, int fsflags, struct uio *fsoptions);
  void	vfs_getnewfsid(struct mount *);
  struct cdev *vfs_getrootfsid(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_oexport_conv(const struct oexport_args *oexp,
  	    struct export_args *exp);
  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);
  extern	TAILQ_HEAD(mntlist, mount) mountlist;	/* mounted filesystem list */
  extern	struct mtx mountlist_mtx;
  extern	struct nfs_public nfs_pub;
  
  /*
   * Declarations for these vfs default operations are located in
   * kern/vfs_default.c, they should be used instead of making "dummy"
   * functions or casting entries in the VFS op table to "enopnotsupp()".
   */
  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;
  
  #else /* !_KERNEL */
  
  #include <sys/cdefs.h>
  
  struct stat;
  
  __BEGIN_DECLS
  int	fhopen(const struct fhandle *, int);
  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	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_ */
  