xref: /xnu-11417.140.69/bsd/sys/mount_internal.h (revision 43a90889846e00bfb5cf1d255cdc0a701a1e05a4) !

/*
 * Copyright (c) 2000-2021 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
/* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
/*
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 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
 */
/*
 * NOTICE: This file was modified by McAfee Research in 2004 to introduce
 * support for mandatory and extensible security protections.  This notice
 * is included in support of clause 2.2 (b) of the Apple Public License,
 * Version 2.0.
 */

#ifndef _SYS_MOUNT_INTERNAL_H_
#define _SYS_MOUNT_INTERNAL_H_

#include <sys/appleapiopts.h>
#ifndef KERNEL
#include <sys/ucred.h>
#else
#include <sys/kernel_types.h>
#include <sys/namei.h>
#endif
#include <sys/_types/_graftdmg_un.h>
#include <sys/queue.h>
#include <sys/lock.h>
#include <net/radix.h>
#include <sys/socket.h>         /* XXX for AF_MAX */
#include <sys/vfs_context.h>            /* XXX for AF_MAX */
#include <sys/mount.h>
#include <sys/cdefs.h>
#include <sys/sysctl.h>

struct label;

#if defined(__i386__) || defined(__x86_64__)
typedef uint64_t  pending_io_t;
#define INCR_PENDING_IO(a, b) OSAddAtomic64((int64_t)(a), (int64_t *)&(b));
#else
typedef uint32_t  pending_io_t;
#define INCR_PENDING_IO(a, b) OSAddAtomic((int32_t)(a), (int32_t *)&(b));
#endif


/*
 * Structure per mounted file system.  Each mounted file system has an
 * array of operations and an instance record.  The file systems are
 * put on a doubly linked list.
 */
TAILQ_HEAD(vnodelst, vnode);

struct mount {
	TAILQ_ENTRY(mount)      mnt_list;                   /* mount list */
	int32_t                 mnt_count;                  /* reference on the mount */
	lck_mtx_t               mnt_mlock;                  /* mutex that protects mount point */
	const struct vfsops     * XNU_PTRAUTH_SIGNED_PTR("mount.vfsops") mnt_op;        /* operations on fs */
	struct vfstable         * XNU_PTRAUTH_SIGNED_PTR("mount.mnt_vtable") mnt_vtable;        /* configuration info */
	struct vnode            * XNU_PTRAUTH_SIGNED_PTR("mount.mnt_vnodecovered") mnt_vnodecovered;    /* vnode we mounted on */
	struct vnodelst         mnt_vnodelist;              /* list of vnodes this mount */
	struct vnodelst         mnt_workerqueue;            /* list of vnodes this mount */
	struct vnodelst         mnt_newvnodes;              /* list of vnodes this mount */
	uint32_t                mnt_flag;                   /* flags */
	uint32_t                mnt_kern_flag;              /* kernel only flags.  NOTE: See mnt_supl_kern_flags below! */
	uint32_t                mnt_compound_ops;           /* Available compound operations */
	uint32_t                mnt_lflag;                  /* mount life cycle flags */
	uint32_t                mnt_maxsymlinklen;          /* max size of short symlink */
	struct vfsstatfs        mnt_vfsstat;                /* cache of filesystem stats */
	qaddr_t                 mnt_data;                   /* private data */
	/* Cached values of the IO constraints for the device */
	uint32_t                mnt_maxreadcnt;             /* Max. byte count for read */
	uint32_t                mnt_maxwritecnt;            /* Max. byte count for write */
	uint32_t                mnt_segreadcnt;             /* Max. segment count for read */
	uint32_t                mnt_segwritecnt;            /* Max. segment count for write */
	uint32_t                mnt_maxsegreadsize;         /* Max. segment read size  */
	uint32_t                mnt_maxsegwritesize;        /* Max. segment write size */
	uint32_t                mnt_alignmentmask;          /* Mask of bits that aren't addressable via DMA */
	uint32_t                mnt_devblocksize;           /* the underlying device block size */
	uint32_t                mnt_ioqueue_depth;          /* the maxiumum number of commands a device can accept */
	uint32_t                mnt_ioscale;                /* scale the various throttles/limits imposed on the amount of I/O in flight */
	uint32_t                mnt_ioflags;                /* flags for  underlying device */
	uint32_t                mnt_minsaturationbytecount; /* if non-zero, mininum amount of writes (in bytes) needed to max out throughput */
	pending_io_t            mnt_pending_write_size __attribute__((aligned(sizeof(pending_io_t))));  /* byte count of pending writes */
	pending_io_t            mnt_pending_read_size  __attribute__((aligned(sizeof(pending_io_t))));  /* byte count of pending reads */
	struct timeval          mnt_last_write_issued_timestamp;
	struct timeval          mnt_last_write_completed_timestamp;
	int64_t                 mnt_max_swappin_available;

	lck_rw_t                mnt_rwlock;                 /* mutex readwrite lock */
	lck_mtx_t               mnt_renamelock;             /* mutex that serializes renames that change shape of tree */
	vnode_t                 mnt_devvp;                  /* the device mounted on for local file systems */
	uint32_t                mnt_devbsdunit;             /* the BSD unit number of the device */
	uint64_t                mnt_throttle_mask;          /* the throttle mask of what devices will be affected by I/O from this mnt */
	void                    *mnt_throttle_info;         /* used by the throttle code */
	int32_t                 mnt_crossref;               /* refernces to cover lookups  crossing into mp */
	int32_t                 mnt_iterref;                /* refernces to cover iterations; drained makes it -ve  */
#if CONFIG_TRIGGERS
	int32_t                 mnt_numtriggers;            /* num of trigger vnodes for this mount */
	vfs_trigger_callback_t  *mnt_triggercallback;
	void                    *mnt_triggerdata;
#endif
	/* XXX 3762912 hack to support HFS filesystem 'owner' */
	uid_t                   mnt_fsowner;
	gid_t                   mnt_fsgroup;

	struct label            *mnt_mntlabel;              /* MAC mount label */

	/*
	 * cache the rootvp of the last mount point
	 * in the chain in the mount struct pointed
	 * to by the vnode sitting in '/'
	 * this cache is used to shortcircuit the
	 * mount chain traversal and allows us
	 * to traverse to the true underlying rootvp
	 * in 1 easy step inside of 'cache_lookup_path'
	 *
	 * make sure to validate against the cached vid
	 * in case the rootvp gets stolen away since
	 * we don't take an explicit long term reference
	 * on it when we mount it
	 */
	vnode_t                 mnt_realrootvp;
	uint32_t                mnt_realrootvp_vid;
	/*
	 * bumped each time a mount or unmount
	 * occurs... its used to invalidate
	 * 'mnt_realrootvp' from the cache
	 */
	uint32_t                mnt_generation;
	/*
	 * if 'MNTK_AUTH_CACHE_TIMEOUT' is
	 * set, then 'mnt_authcache_ttl' is
	 * the time-to-live for the per-vnode authentication cache
	 * on this mount... if zero, no cache is maintained...
	 * if 'MNTK_AUTH_CACHE_TIMEOUT' isn't set, its the
	 * time-to-live for the cached lookup right for
	 * volumes marked 'MNTK_AUTH_OPAQUE'.
	 */
	int                     mnt_authcache_ttl;
	char                    fstypename_override[MFSTYPENAMELEN];

	uint32_t                mnt_iobufinuse;

	void                    *mnt_disk_conditioner_info;

	lck_mtx_t               mnt_iter_lock;              /* mutex that protects iteration of vnodes */

	uint64_t                mnt_mount_id;               /* system-wide unique mount ID */
	uint32_t                mnt_supl_kern_flag;         /* Supplemental kernel-only mount flags */
};

/*
 * default number of seconds to keep cached lookup
 * rights valid on mounts marked MNTK_AUTH_OPAQUE
 */
#define CACHED_LOOKUP_RIGHT_TTL         2

/*
 * ioflags
 */
#define MNT_IOFLAGS_FUA_SUPPORTED       0x00000001
#define MNT_IOFLAGS_UNMAP_SUPPORTED     0x00000002
#define MNT_IOFLAGS_IOSCHED_SUPPORTED   0x00000004
#define MNT_IOFLAGS_CSUNMAP_SUPPORTED   0x00000008
#define MNT_IOFLAGS_SWAPPIN_SUPPORTED   0x00000010
#define MNT_IOFLAGS_FUSION_DRIVE        0x00000020
#define MNT_IOFLAGS_PERIPHERAL_DRIVE    0x00000040 /* External: Attached directly to the system (USB,TBT,FW,etc.) */

/*
 * ioqueue depth for devices that don't report one
 */
#define MNT_DEFAULT_IOQUEUE_DEPTH       32

/*
 * mnt_ioscale value for the given ioqueue depth
 */
#define MNT_IOSCALE(ioqueue_depth)      ((ioqueue_depth + (MNT_DEFAULT_IOQUEUE_DEPTH - 1)) / MNT_DEFAULT_IOQUEUE_DEPTH)

/* mount point to which dead vps point to */
extern struct mount * const dead_mountp;

/*
 * 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.
 *
 * Note:	We are counting down on new bit assignments.  This is
 *		because the bits here were broken out from the high bits
 *		of the mount flags.
 */
#define MNTK_FSKIT              0x00000020      /* Volume is a FSKit mount */
#define MNTK_SYSTEM             0x00000040      /* Volume associated with system volume (do not allow unmount) */
#define MNTK_NOSWAP             0x00000080      /* swap files cannot be used on this mount */
#define MNTK_SWAP_MOUNT         0x00000100      /* we are swapping to this mount */
#define MNTK_DENY_READDIREXT    0x00000200      /* Deny Extended-style readdir's for this volume */
#define MNTK_PERMIT_UNMOUNT     0x00000400      /* Allow (non-forced) unmounts by UIDs other than the one that mounted the volume */
#define MNTK_TYPENAME_OVERRIDE  0x00000800      /* override the fstypename for statfs() */
#define MNTK_KERNEL_MOUNT       0x00001000      /* mount came from kernel side */
#ifdef CONFIG_IMGSRC_ACCESS
#define MNTK_HAS_MOVED          0x00002000
#endif /* CONFIG_IMGSRC_ACCESS */
#define MNTK_BACKS_ROOT         0x00004000      /* mount contains a disk image backing the root filesystem - therefore it mustn't be unmounted */
#define MNTK_AUTH_CACHE_TTL     0x00008000      /* rights cache has TTL - TTL of 0 disables cache */
#define MNTK_PATH_FROM_ID       0x00010000      /* mounted file system supports id-to-path lookups */
#define MNTK_UNMOUNT_PREFLIGHT  0x00020000      /* mounted file system wants preflight check during unmount */
#define MNTK_NAMED_STREAMS      0x00040000      /* mounted file system supports Named Streams VNOPs */
#define MNTK_EXTENDED_ATTRS     0x00080000      /* mounted file system supports Extended Attributes VNOPs */
#define MNTK_LOCK_LOCAL         0x00100000      /* advisory locking is done above the VFS itself */
#define MNTK_VIRTUALDEV         0x00200000      /* mounted on a virtual device i.e. a disk image */
#define MNTK_ROOTDEV            0x00400000      /* this filesystem resides on the same device as the root - appears unused as of 2020 */
#define MNTK_SSD                0x00800000      /* underlying device is of the solid state variety */
#define MNTK_UNMOUNT            0x01000000      /* unmount in progress */
#define MNTK_MWAIT              0x02000000      /* waiting for unmount to finish - appears unused as of 2020 */
#define MNTK_WANTRDWR           0x04000000      /* upgrade to read/write requested */
#define MNTK_SYSTEMDATA         0x08000000      /* volume is a Data volume tightly linked with System root volume. Firmlinks, etc */
#define MNTK_DIR_HARDLINKS      0x10000000      /* mounted file system supports directory hard links */
#define MNTK_AUTH_OPAQUE        0x20000000      /* authorisation decisions are not made locally */
#define MNTK_AUTH_OPAQUE_ACCESS 0x40000000      /* VNOP_ACCESS is reliable for remote auth */
#define MNTK_EXTENDED_SECURITY  0x80000000      /* extended security supported */


/*
 * Internal supplemental FS control flags stored in mnt_supl_kern_flag
 *
 * NOTE: The 32 bits in the above-mentioned 32bit flag word (mnt_kern_flag) have been
 * exhausted, so this is intended as a supplement.
 */
#define MNTK_SUPL_BASESYSTEM    0x00000001
#define MNTK_SUPL_USE_FULLSYNC  0x00000002

/*
 * Mount Lifecycle Flags (stored in mnt_lflag)
 */
#define MNT_LNOTRESP            0x00000001      /* mount not responding */
#define MNT_LUNMOUNT            0x00000002      /* mount in unmount */
#define MNT_LFORCE              0x00000004      /* mount in forced unmount */
#define MNT_LDRAIN              0x00000008      /* mount in drain */
#define MNT_LITER               0x00000010      /* mount in iteration */
#define MNT_LNEWVN              0x00000020      /* mount has new vnodes created */
#define MNT_LWAIT               0x00000040      /* wait for unmount op */
#define MNT_LMOUNT              0x00000080      /* not finished mounting */
#define MNT_LDEAD               0x00000100      /* mount already unmounted*/
#define MNT_LNOSUB              0x00000200      /* submount - no recursion */

/*
 * 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.
 */
struct vfstable {
	const 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 */
	int         (*vfc_mountroot)(mount_t, vnode_t, vfs_context_t);      /* if != NULL, routine to mount root */
	struct      vfstable *vfc_next;     /* next in list */
	int32_t     vfc_reserved1;
	int32_t     vfc_reserved2;
	int         vfc_vfsflags;           /* for optional types */
	void       *vfc_descptr;            /* desc table allocated address */
	uint32_t    vfc_descsize;           /* number of elements in desc table */
	struct sysctl_oid       *vfc_sysctl;    /* dynamically registered sysctl node */
};

/* vfc_vfsflags: */
#define VFC_VFSLOCALARGS        0x002
#define VFC_VFSGENERICARGS      0x004
#define VFC_VFSNATIVEXATTR      0x010
#define VFC_VFSCANMOUNTROOT 0x020
#define VFC_VFSPREFLIGHT        0x040
#define VFC_VFSREADDIR_EXTENDED 0x080
#define VFC_VFS64BITREADY       0x100
#define VFC_VFSNOMACLABEL       0x1000
#define VFC_VFSVNOP_PAGEINV2    0x2000
#define VFC_VFSVNOP_PAGEOUTV2   0x4000
#define VFC_VFSVNOP_NOUPDATEID_RENAME   0x8000
#define VFC_VFSVNOP_SECLUDE_RENAME      0x10000

extern int maxvfstypenum;               /* highest defined filesystem type */
extern struct vfstable  *vfsconf;       /* head of list of filesystem types */
extern const int maxvfsslots;           /* Maximum statically allocated slots available to be used */
extern int numused_vfsslots;    /* number of statically allocated slots already used */
extern int numregistered_fses;  /* number of total registered filesystems */

/* the following two are xnu private */
struct vfstable *       vfstable_add(struct     vfstable *);
int     vfstable_del(struct vfstable *);


struct vfsmount_args {
	union {
		struct {
			char * mnt_fspec;
			void * mnt_fsdata;
		} mnt_localfs_args;
		struct {
			void *  mnt_fsdata;             /* FS specific */
		} mnt_remotefs_args;
	} mountfs_args;
};


/*
 * LP64 *user* version of statfs structure.
 * NOTE - must be kept in sync with struct statfs in mount.h
 */
struct user64_statfs {
	short           f_otype;                /* TEMPORARY SHADOW COPY OF f_type */
	short           f_oflags;               /* TEMPORARY SHADOW COPY OF f_flags */
	user64_long_t   f_bsize;                /* fundamental file system block size */
	user64_long_t   f_iosize;               /* optimal transfer block size */
	user64_long_t   f_blocks;               /* total data blocks in file system */
	user64_long_t   f_bfree;                /* free blocks in fs */
	user64_long_t   f_bavail;               /* free blocks avail to non-superuser */
	user64_long_t   f_files;                /* total file nodes in file system */
	user64_long_t   f_ffree;                /* free file nodes in fs */
	fsid_t          f_fsid;                 /* file system id */
	uid_t           f_owner;                /* user that mounted the filesystem */
	short           f_reserved1;            /* spare for later */
	short           f_type;                 /* type of filesystem */
	user64_long_t   f_flags;                /* copy of mount exported flags */
	user64_long_t   f_reserved2[2];         /* reserved for future use */
	char            f_fstypename[MFSNAMELEN]; /* fs type name */
	char            f_mntonname[MNAMELEN];  /* directory on which mounted */
	char            f_mntfromname[MNAMELEN];/* mounted filesystem */
	char            f_reserved3;    /* For alignment */
	user64_long_t   f_reserved4[4]; /* For future use */
};

/*
 * ILP32 *user* version of statfs structure.
 * NOTE - must be kept in sync with struct statfs in mount.h
 */
struct user32_statfs {
	short           f_otype;                /* TEMPORARY SHADOW COPY OF f_type */
	short           f_oflags;               /* TEMPORARY SHADOW COPY OF f_flags */
	user32_long_t   f_bsize;                /* fundamental file system block size */
	user32_long_t   f_iosize;               /* optimal transfer block size */
	user32_long_t   f_blocks;               /* total data blocks in file system */
	user32_long_t   f_bfree;                /* free blocks in fs */
	user32_long_t   f_bavail;               /* free blocks avail to non-superuser */
	user32_long_t   f_files;                /* total file nodes in file system */
	user32_long_t   f_ffree;                /* free file nodes in fs */
	fsid_t          f_fsid;                 /* file system id */
	uid_t           f_owner;                /* user that mounted the filesystem */
	short           f_reserved1;    /* spare for later */
	short           f_type;                 /* type of filesystem */
	user32_long_t       f_flags;            /* copy of mount exported flags */
	user32_long_t f_reserved2[2];   /* reserved for future use */
	char            f_fstypename[MFSNAMELEN]; /* fs type name */
	char            f_mntonname[MNAMELEN];  /* directory on which mounted */
	char            f_mntfromname[MNAMELEN];/* mounted filesystem */
	char            f_reserved3;    /* For alignment */
	user32_long_t   f_reserved4[4]; /* For future use */
};

/*
 * throttle I/Os are affected only by normal I/Os happening on the same spindle.  Currently we use a 64-bit integer to
 * represent what devices are affected, so we can handle at most 64 different spindles.  Since
 * throttled I/O is usually useful in non-server environment only, this number is enough in most cases.
 */
#define LOWPRI_MAX_NUM_DEV 64

__BEGIN_DECLS

extern uint32_t mount_generation;
extern TAILQ_HEAD(mntlist, mount) mountlist;
void mount_list_lock(void);
void mount_list_unlock(void);
void mount_lock_init(mount_t);
void mount_lock_destroy(mount_t);
void mount_lock(mount_t);
void mount_lock_spin(mount_t);
void mount_unlock(mount_t);
void mount_iterate_lock(mount_t);
void mount_iterate_unlock(mount_t);
void mount_lock_renames(mount_t);
void mount_unlock_renames(mount_t);
void mount_ref(mount_t, int);
void mount_drop(mount_t, int);
int  mount_refdrain(mount_t);

/* vfs_rootmountalloc should be kept as a private api */
errno_t vfs_rootmountalloc(const char *, const char *, mount_t *mpp);

int vfs_mount_recovery(void);

typedef uint32_t vfs_switch_root_flags_t;
#define VFSSR_VIRTUALDEV_PROHIBITED     0x01 /* Not allowed to pivot into virtual devices (disk images).
	                                      * This is really just because we don't have a great way to find
	                                      * the filesystem that backs the image in order to set
	                                      * MNTK_BACKS_ROOT on it, which would prevent even forced-unmounts.
	                                      * Also, lots of disk images are backed by userspace processes,
	                                      * which also seems like a bad idea for the root filesystem. */

int vfs_switch_root(const char *, const char *, vfs_switch_root_flags_t);

int     vfs_mountroot(void);
void    vfs_unmountall(int only_non_system);
int     safedounmount(struct mount *, int, vfs_context_t);
int     dounmount(struct mount *, int, int, vfs_context_t);
void    dounmount_submounts(struct mount *, int, vfs_context_t);
int     vfs_setmounting(vnode_t);
void    vfs_clearmounting(vnode_t);
void    vfs_setmountedon(vnode_t);

/* xnu internal api */
void  mount_dropcrossref(mount_t, vnode_t, int);
mount_t mount_lookupby_volfsid(int, int);
mount_t mount_list_lookupby_fsid(fsid_t *, int, int);
int  mount_list_add(mount_t);
void mount_list_remove(mount_t);
int  mount_iterref(mount_t, int);
int  mount_isdrained(mount_t, int);
void mount_iterdrop(mount_t);
void mount_iterdrain(mount_t);
void mount_iterreset(mount_t);

/* These flags are used as flag bits in the `internal_flags` argument to mount_common */
/* Private NFS spi */
#define KERNEL_MOUNT_NOAUTH             0x01 /* Don't check the UID of the directory we are mounting on */
#define KERNEL_MOUNT_PERMIT_UNMOUNT     0x02 /* Allow (non-forced) unmounts by users other the one who mounted the volume */
/* used by snapshot mounting SPI */
#define KERNEL_MOUNT_SNAPSHOT           0x04 /* Mounting a snapshot */
#define KERNEL_MOUNT_DATAVOL            0x08 /* mount the data volume */
#define KERNEL_MOUNT_VMVOL              0x10 /* mount the VM volume */
#define KERNEL_MOUNT_PREBOOTVOL         0x20 /* mount the Preboot volume */
#define KERNEL_MOUNT_RECOVERYVOL        0x40 /* mount the Recovery volume */
#define KERNEL_MOUNT_BASESYSTEMROOT     0x80 /* mount a base root volume "instead of" the full root volume (only used during bsd_init) */
#define KERNEL_MOUNT_DEVFS             0x100 /* kernel startup mount of devfs */
#define KERNEL_MOUNT_FMOUNT            0x200 /* is fmount() system call */
#define KERNEL_MOUNT_KMOUNT            0x400 /* is kernel_mount() call */

/* mask for checking if any of the "mount volume by role" flags are set */
#define KERNEL_MOUNT_VOLBYROLE_MASK (KERNEL_MOUNT_DATAVOL | KERNEL_MOUNT_VMVOL | KERNEL_MOUNT_PREBOOTVOL | KERNEL_MOUNT_RECOVERYVOL)

/* mask for sanitizing inputs to kernel_mount() */
#define KERNEL_MOUNT_SANITIZE_MASK (~(KERNEL_MOUNT_FMOUNT))

/*
 * NOTE: kernel_mount() does not force MNT_NOSUID, MNT_NOEXEC, or MNT_NODEC for non-privileged
 * mounting credentials, as the mount(2) system call does.
 */
int kernel_mount(const char *, vnode_t, vnode_t, const char *, void *, size_t, int, uint32_t, vfs_context_t);

/* Throttled I/O API.  KPI/SPI is in systm.h. */

int  throttle_get_io_policy(struct uthread **ut);
int  throttle_get_passive_io_policy(struct uthread **ut);
void *throttle_info_update_by_mount(mount_t mp);
void rethrottle_thread(uthread_t ut);


/* throttled I/O helper function */
/* convert the lowest bit to a device index */
extern int num_trailing_0(uint64_t n);

/* sync lock */
extern int sync_timeout_seconds;

KALLOC_TYPE_DECLARE(mount_zone);

__END_DECLS

#endif /* !_SYS_MOUNT_INTERNAL_H_ */