xref: /xnu-8020.101.4/bsd/sys/mount_internal.h (revision e7776783b89a353188416a9a346c6cdb4928faad)
1 /*
2  * Copyright (c) 2000-2018 Apple Inc. All rights reserved.
3  *
4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5  *
6  * This file contains Original Code and/or Modifications of Original Code
7  * as defined in and that are subject to the Apple Public Source License
8  * Version 2.0 (the 'License'). You may not use this file except in
9  * compliance with the License. The rights granted to you under the License
10  * may not be used to create, or enable the creation or redistribution of,
11  * unlawful or unlicensed copies of an Apple operating system, or to
12  * circumvent, violate, or enable the circumvention or violation of, any
13  * terms of an Apple operating system software license agreement.
14  *
15  * Please obtain a copy of the License at
16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
17  *
18  * The Original Code and all software distributed under the License are
19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23  * Please see the License for the specific language governing rights and
24  * limitations under the License.
25  *
26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27  */
28 /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
29 /*
30  * Copyright (c) 1989, 1991, 1993
31  *	The Regents of the University of California.  All rights reserved.
32  *
33  * Redistribution and use in source and binary forms, with or without
34  * modification, are permitted provided that the following conditions
35  * are met:
36  * 1. Redistributions of source code must retain the above copyright
37  *    notice, this list of conditions and the following disclaimer.
38  * 2. Redistributions in binary form must reproduce the above copyright
39  *    notice, this list of conditions and the following disclaimer in the
40  *    documentation and/or other materials provided with the distribution.
41  * 3. All advertising materials mentioning features or use of this software
42  *    must display the following acknowledgement:
43  *	This product includes software developed by the University of
44  *	California, Berkeley and its contributors.
45  * 4. Neither the name of the University nor the names of its contributors
46  *    may be used to endorse or promote products derived from this software
47  *    without specific prior written permission.
48  *
49  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
50  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
51  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
52  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
53  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
54  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
55  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
56  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
57  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
58  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
59  * SUCH DAMAGE.
60  *
61  *	@(#)mount.h	8.21 (Berkeley) 5/20/95
62  */
63 /*
64  * NOTICE: This file was modified by McAfee Research in 2004 to introduce
65  * support for mandatory and extensible security protections.  This notice
66  * is included in support of clause 2.2 (b) of the Apple Public License,
67  * Version 2.0.
68  */
69 
70 #ifndef _SYS_MOUNT_INTERNAL_H_
71 #define _SYS_MOUNT_INTERNAL_H_
72 
73 #include <sys/appleapiopts.h>
74 #ifndef KERNEL
75 #include <sys/ucred.h>
76 #else
77 #include <sys/kernel_types.h>
78 #include <sys/namei.h>
79 #endif
80 #include <sys/queue.h>
81 #include <sys/lock.h>
82 #include <net/radix.h>
83 #include <sys/socket.h>         /* XXX for AF_MAX */
84 #include <sys/vfs_context.h>            /* XXX for AF_MAX */
85 #include <sys/mount.h>
86 #include <sys/cdefs.h>
87 #include <sys/sysctl.h>
88 
89 struct label;
90 
91 #if defined(__i386__) || defined(__x86_64__)
92 typedef uint64_t  pending_io_t;
93 #define INCR_PENDING_IO(a, b) OSAddAtomic64((int64_t)(a), (int64_t *)&(b));
94 #else
95 typedef uint32_t  pending_io_t;
96 #define INCR_PENDING_IO(a, b) OSAddAtomic((int32_t)(a), (int32_t *)&(b));
97 #endif
98 
99 
100 /*
101  * Structure per mounted file system.  Each mounted file system has an
102  * array of operations and an instance record.  The file systems are
103  * put on a doubly linked list.
104  */
105 TAILQ_HEAD(vnodelst, vnode);
106 
107 struct mount {
108 	TAILQ_ENTRY(mount)      mnt_list;                   /* mount list */
109 	int32_t                 mnt_count;                  /* reference on the mount */
110 	lck_mtx_t               mnt_mlock;                  /* mutex that protects mount point */
111 	const struct vfsops     * XNU_PTRAUTH_SIGNED_PTR("mount.vfsops") mnt_op;        /* operations on fs */
112 	struct vfstable         * XNU_PTRAUTH_SIGNED_PTR("mount.mnt_vtable") mnt_vtable;        /* configuration info */
113 	struct vnode            * XNU_PTRAUTH_SIGNED_PTR("mount.mnt_vnodecovered") mnt_vnodecovered;    /* vnode we mounted on */
114 	struct vnodelst         mnt_vnodelist;              /* list of vnodes this mount */
115 	struct vnodelst         mnt_workerqueue;            /* list of vnodes this mount */
116 	struct vnodelst         mnt_newvnodes;              /* list of vnodes this mount */
117 	uint32_t                mnt_flag;                   /* flags */
118 	uint32_t                mnt_kern_flag;              /* kernel only flags.  NOTE: See mnt_supl_kern_flags below! */
119 	uint32_t                mnt_compound_ops;           /* Available compound operations */
120 	uint32_t                mnt_lflag;                  /* mount life cycle flags */
121 	uint32_t                mnt_maxsymlinklen;          /* max size of short symlink */
122 	struct vfsstatfs        mnt_vfsstat;                /* cache of filesystem stats */
123 	qaddr_t                 mnt_data;                   /* private data */
124 	/* Cached values of the IO constraints for the device */
125 	uint32_t                mnt_maxreadcnt;             /* Max. byte count for read */
126 	uint32_t                mnt_maxwritecnt;            /* Max. byte count for write */
127 	uint32_t                mnt_segreadcnt;             /* Max. segment count for read */
128 	uint32_t                mnt_segwritecnt;            /* Max. segment count for write */
129 	uint32_t                mnt_maxsegreadsize;         /* Max. segment read size  */
130 	uint32_t                mnt_maxsegwritesize;        /* Max. segment write size */
131 	uint32_t                mnt_alignmentmask;          /* Mask of bits that aren't addressable via DMA */
132 	uint32_t                mnt_devblocksize;           /* the underlying device block size */
133 	uint32_t                mnt_ioqueue_depth;          /* the maxiumum number of commands a device can accept */
134 	uint32_t                mnt_ioscale;                /* scale the various throttles/limits imposed on the amount of I/O in flight */
135 	uint32_t                mnt_ioflags;                /* flags for  underlying device */
136 	uint32_t                mnt_minsaturationbytecount; /* if non-zero, mininum amount of writes (in bytes) needed to max out throughput */
137 	pending_io_t            mnt_pending_write_size __attribute__((aligned(sizeof(pending_io_t))));  /* byte count of pending writes */
138 	pending_io_t            mnt_pending_read_size  __attribute__((aligned(sizeof(pending_io_t))));  /* byte count of pending reads */
139 	struct timeval          mnt_last_write_issued_timestamp;
140 	struct timeval          mnt_last_write_completed_timestamp;
141 	int64_t                 mnt_max_swappin_available;
142 
143 	lck_rw_t                mnt_rwlock;                 /* mutex readwrite lock */
144 	lck_mtx_t               mnt_renamelock;             /* mutex that serializes renames that change shape of tree */
145 	vnode_t                 mnt_devvp;                  /* the device mounted on for local file systems */
146 	uint32_t                mnt_devbsdunit;             /* the BSD unit number of the device */
147 	uint64_t                mnt_throttle_mask;          /* the throttle mask of what devices will be affected by I/O from this mnt */
148 	void                    *mnt_throttle_info;         /* used by the throttle code */
149 	int32_t                 mnt_crossref;               /* refernces to cover lookups  crossing into mp */
150 	int32_t                 mnt_iterref;                /* refernces to cover iterations; drained makes it -ve  */
151 #if CONFIG_TRIGGERS
152 	int32_t                 mnt_numtriggers;            /* num of trigger vnodes for this mount */
153 	vfs_trigger_callback_t  *mnt_triggercallback;
154 	void                    *mnt_triggerdata;
155 #endif
156 	/* XXX 3762912 hack to support HFS filesystem 'owner' */
157 	uid_t                   mnt_fsowner;
158 	gid_t                   mnt_fsgroup;
159 
160 	struct label            *mnt_mntlabel;              /* MAC mount label */
161 
162 	/*
163 	 * cache the rootvp of the last mount point
164 	 * in the chain in the mount struct pointed
165 	 * to by the vnode sitting in '/'
166 	 * this cache is used to shortcircuit the
167 	 * mount chain traversal and allows us
168 	 * to traverse to the true underlying rootvp
169 	 * in 1 easy step inside of 'cache_lookup_path'
170 	 *
171 	 * make sure to validate against the cached vid
172 	 * in case the rootvp gets stolen away since
173 	 * we don't take an explicit long term reference
174 	 * on it when we mount it
175 	 */
176 	vnode_t                 mnt_realrootvp;
177 	uint32_t                mnt_realrootvp_vid;
178 	/*
179 	 * bumped each time a mount or unmount
180 	 * occurs... its used to invalidate
181 	 * 'mnt_realrootvp' from the cache
182 	 */
183 	uint32_t                mnt_generation;
184 	/*
185 	 * if 'MNTK_AUTH_CACHE_TIMEOUT' is
186 	 * set, then 'mnt_authcache_ttl' is
187 	 * the time-to-live for the per-vnode authentication cache
188 	 * on this mount... if zero, no cache is maintained...
189 	 * if 'MNTK_AUTH_CACHE_TIMEOUT' isn't set, its the
190 	 * time-to-live for the cached lookup right for
191 	 * volumes marked 'MNTK_AUTH_OPAQUE'.
192 	 */
193 	int                     mnt_authcache_ttl;
194 	char                    fstypename_override[MFSTYPENAMELEN];
195 
196 	uint32_t                mnt_iobufinuse;
197 
198 	void                    *mnt_disk_conditioner_info;
199 
200 	lck_mtx_t               mnt_iter_lock;              /* mutex that protects iteration of vnodes */
201 
202 	uint64_t                mnt_mount_id;               /* system-wide unique mount ID */
203 	uint32_t                mnt_supl_kern_flag;         /* Supplemental kernel-only mount flags */
204 };
205 
206 /*
207  * default number of seconds to keep cached lookup
208  * rights valid on mounts marked MNTK_AUTH_OPAQUE
209  */
210 #define CACHED_LOOKUP_RIGHT_TTL         2
211 
212 /*
213  * ioflags
214  */
215 #define MNT_IOFLAGS_FUA_SUPPORTED       0x00000001
216 #define MNT_IOFLAGS_UNMAP_SUPPORTED     0x00000002
217 #define MNT_IOFLAGS_IOSCHED_SUPPORTED   0x00000004
218 #define MNT_IOFLAGS_CSUNMAP_SUPPORTED   0x00000008
219 #define MNT_IOFLAGS_SWAPPIN_SUPPORTED   0x00000010
220 #define MNT_IOFLAGS_FUSION_DRIVE        0x00000020
221 #define MNT_IOFLAGS_PERIPHERAL_DRIVE    0x00000040 /* External: Attached directly to the system (USB,TBT,FW,etc.) */
222 
223 /*
224  * ioqueue depth for devices that don't report one
225  */
226 #define MNT_DEFAULT_IOQUEUE_DEPTH       32
227 
228 /*
229  * mnt_ioscale value for the given ioqueue depth
230  */
231 #define MNT_IOSCALE(ioqueue_depth)      ((ioqueue_depth + (MNT_DEFAULT_IOQUEUE_DEPTH - 1)) / MNT_DEFAULT_IOQUEUE_DEPTH)
232 
233 /* mount point to which dead vps point to */
234 extern struct mount * const dead_mountp;
235 
236 /*
237  * Internal filesystem control flags stored in mnt_kern_flag.
238  *
239  * MNTK_UNMOUNT locks the mount entry so that name lookup cannot proceed
240  * past the mount point.  This keeps the subtree stable during mounts
241  * and unmounts.
242  *
243  * Note:	We are counting down on new bit assignments.  This is
244  *		because the bits here were broken out from the high bits
245  *		of the mount flags.
246  */
247 #define MNTK_SYSTEM             0x00000040      /* Volume associated with system volume (do not allow unmount) */
248 #define MNTK_NOSWAP             0x00000080      /* swap files cannot be used on this mount */
249 #define MNTK_SWAP_MOUNT         0x00000100      /* we are swapping to this mount */
250 #define MNTK_DENY_READDIREXT    0x00000200      /* Deny Extended-style readdir's for this volume */
251 #define MNTK_PERMIT_UNMOUNT     0x00000400      /* Allow (non-forced) unmounts by UIDs other than the one that mounted the volume */
252 #define MNTK_TYPENAME_OVERRIDE  0x00000800      /* override the fstypename for statfs() */
253 #define MNTK_KERNEL_MOUNT       0x00001000      /* mount came from kernel side */
254 #ifdef CONFIG_IMGSRC_ACCESS
255 #define MNTK_HAS_MOVED          0x00002000
256 #endif /* CONFIG_IMGSRC_ACCESS */
257 #define MNTK_BACKS_ROOT         0x00004000      /* mount contains a disk image backing the root filesystem - therefore it mustn't be unmounted */
258 #define MNTK_AUTH_CACHE_TTL     0x00008000      /* rights cache has TTL - TTL of 0 disables cache */
259 #define MNTK_PATH_FROM_ID       0x00010000      /* mounted file system supports id-to-path lookups */
260 #define MNTK_UNMOUNT_PREFLIGHT  0x00020000      /* mounted file system wants preflight check during unmount */
261 #define MNTK_NAMED_STREAMS      0x00040000      /* mounted file system supports Named Streams VNOPs */
262 #define MNTK_EXTENDED_ATTRS     0x00080000      /* mounted file system supports Extended Attributes VNOPs */
263 #define MNTK_LOCK_LOCAL         0x00100000      /* advisory locking is done above the VFS itself */
264 #define MNTK_VIRTUALDEV         0x00200000      /* mounted on a virtual device i.e. a disk image */
265 #define MNTK_ROOTDEV            0x00400000      /* this filesystem resides on the same device as the root - appears unused as of 2020 */
266 #define MNTK_SSD                0x00800000      /* underlying device is of the solid state variety */
267 #define MNTK_UNMOUNT            0x01000000      /* unmount in progress */
268 #define MNTK_MWAIT              0x02000000      /* waiting for unmount to finish - appears unused as of 2020 */
269 #define MNTK_WANTRDWR           0x04000000      /* upgrade to read/write requested */
270 #define MNTK_SYSTEMDATA         0x08000000      /* volume is a Data volume tightly linked with System root volume. Firmlinks, etc */
271 #define MNTK_DIR_HARDLINKS      0x10000000      /* mounted file system supports directory hard links */
272 #define MNTK_AUTH_OPAQUE        0x20000000      /* authorisation decisions are not made locally */
273 #define MNTK_AUTH_OPAQUE_ACCESS 0x40000000      /* VNOP_ACCESS is reliable for remote auth */
274 #define MNTK_EXTENDED_SECURITY  0x80000000      /* extended security supported */
275 
276 
277 /*
278  * Internal supplemental FS control flags stored in mnt_supl_kern_flag
279  *
280  * NOTE: The 32 bits in the above-mentioned 32bit flag word (mnt_kern_flag) have been
281  * exhausted, so this is intended as a supplement.
282  */
283 #define MNTK_SUPL_BASESYSTEM    0x00000001
284 
285 
286 /*
287  * Mount Lifecycle Flags (stored in mnt_lflag)
288  */
289 #define MNT_LNOTRESP            0x00000001      /* mount not responding */
290 #define MNT_LUNMOUNT            0x00000002      /* mount in unmount */
291 #define MNT_LFORCE              0x00000004      /* mount in forced unmount */
292 #define MNT_LDRAIN              0x00000008      /* mount in drain */
293 #define MNT_LITER               0x00000010      /* mount in iteration */
294 #define MNT_LNEWVN              0x00000020      /* mount has new vnodes created */
295 #define MNT_LWAIT               0x00000040      /* wait for unmount op */
296 #define MNT_LMOUNT              0x00000080      /* not finished mounting */
297 #define MNT_LDEAD               0x00000100      /* mount already unmounted*/
298 #define MNT_LNOSUB              0x00000200      /* submount - no recursion */
299 
300 /*
301  * Filesystem configuration information. One of these exists for each
302  * type of filesystem supported by the kernel. These are searched at
303  * mount time to identify the requested filesystem.
304  */
305 struct vfstable {
306 	const struct vfsops *vfc_vfsops;/* filesystem operations vector */
307 	char        vfc_name[MFSNAMELEN];   /* filesystem type name */
308 	int         vfc_typenum;            /* historic filesystem type number */
309 	int         vfc_refcount;           /* number mounted of this type */
310 	int         vfc_flags;              /* permanent flags */
311 	int         (*vfc_mountroot)(mount_t, vnode_t, vfs_context_t);      /* if != NULL, routine to mount root */
312 	struct      vfstable *vfc_next;     /* next in list */
313 	int32_t     vfc_reserved1;
314 	int32_t     vfc_reserved2;
315 	int         vfc_vfsflags;           /* for optional types */
316 	void       *vfc_descptr;            /* desc table allocated address */
317 	uint32_t    vfc_descsize;           /* number of elements in desc table */
318 	struct sysctl_oid       *vfc_sysctl;    /* dynamically registered sysctl node */
319 };
320 
321 /* vfc_vfsflags: */
322 #define VFC_VFSLOCALARGS        0x002
323 #define VFC_VFSGENERICARGS      0x004
324 #define VFC_VFSNATIVEXATTR      0x010
325 #define VFC_VFSCANMOUNTROOT 0x020
326 #define VFC_VFSPREFLIGHT        0x040
327 #define VFC_VFSREADDIR_EXTENDED 0x080
328 #define VFC_VFS64BITREADY       0x100
329 #define VFC_VFSNOMACLABEL       0x1000
330 #define VFC_VFSVNOP_PAGEINV2    0x2000
331 #define VFC_VFSVNOP_PAGEOUTV2   0x4000
332 #define VFC_VFSVNOP_NOUPDATEID_RENAME   0x8000
333 #define VFC_VFSVNOP_SECLUDE_RENAME      0x10000
334 
335 extern int maxvfstypenum;               /* highest defined filesystem type */
336 extern struct vfstable  *vfsconf;       /* head of list of filesystem types */
337 extern const int maxvfsslots;           /* Maximum statically allocated slots available to be used */
338 extern int numused_vfsslots;    /* number of statically allocated slots already used */
339 extern int numregistered_fses;  /* number of total registered filesystems */
340 
341 /* the following two are xnu private */
342 struct vfstable *       vfstable_add(struct     vfstable *);
343 int     vfstable_del(struct vfstable *);
344 
345 
346 struct vfsmount_args {
347 	union {
348 		struct {
349 			char * mnt_fspec;
350 			void * mnt_fsdata;
351 		} mnt_localfs_args;
352 		struct {
353 			void *  mnt_fsdata;             /* FS specific */
354 		} mnt_remotefs_args;
355 	} mountfs_args;
356 };
357 
358 
359 /*
360  * LP64 *user* version of statfs structure.
361  * NOTE - must be kept in sync with struct statfs in mount.h
362  */
363 struct user64_statfs {
364 	short           f_otype;                /* TEMPORARY SHADOW COPY OF f_type */
365 	short           f_oflags;               /* TEMPORARY SHADOW COPY OF f_flags */
366 	user64_long_t   f_bsize;                /* fundamental file system block size */
367 	user64_long_t   f_iosize;               /* optimal transfer block size */
368 	user64_long_t   f_blocks;               /* total data blocks in file system */
369 	user64_long_t   f_bfree;                /* free blocks in fs */
370 	user64_long_t   f_bavail;               /* free blocks avail to non-superuser */
371 	user64_long_t   f_files;                /* total file nodes in file system */
372 	user64_long_t   f_ffree;                /* free file nodes in fs */
373 	fsid_t          f_fsid;                 /* file system id */
374 	uid_t           f_owner;                /* user that mounted the filesystem */
375 	short           f_reserved1;            /* spare for later */
376 	short           f_type;                 /* type of filesystem */
377 	user64_long_t   f_flags;                /* copy of mount exported flags */
378 	user64_long_t   f_reserved2[2];         /* reserved for future use */
379 	char            f_fstypename[MFSNAMELEN]; /* fs type name */
380 	char            f_mntonname[MNAMELEN];  /* directory on which mounted */
381 	char            f_mntfromname[MNAMELEN];/* mounted filesystem */
382 	char            f_reserved3;    /* For alignment */
383 	user64_long_t   f_reserved4[4]; /* For future use */
384 };
385 
386 /*
387  * ILP32 *user* version of statfs structure.
388  * NOTE - must be kept in sync with struct statfs in mount.h
389  */
390 struct user32_statfs {
391 	short           f_otype;                /* TEMPORARY SHADOW COPY OF f_type */
392 	short           f_oflags;               /* TEMPORARY SHADOW COPY OF f_flags */
393 	user32_long_t   f_bsize;                /* fundamental file system block size */
394 	user32_long_t   f_iosize;               /* optimal transfer block size */
395 	user32_long_t   f_blocks;               /* total data blocks in file system */
396 	user32_long_t   f_bfree;                /* free blocks in fs */
397 	user32_long_t   f_bavail;               /* free blocks avail to non-superuser */
398 	user32_long_t   f_files;                /* total file nodes in file system */
399 	user32_long_t   f_ffree;                /* free file nodes in fs */
400 	fsid_t          f_fsid;                 /* file system id */
401 	uid_t           f_owner;                /* user that mounted the filesystem */
402 	short           f_reserved1;    /* spare for later */
403 	short           f_type;                 /* type of filesystem */
404 	user32_long_t       f_flags;            /* copy of mount exported flags */
405 	user32_long_t f_reserved2[2];   /* reserved for future use */
406 	char            f_fstypename[MFSNAMELEN]; /* fs type name */
407 	char            f_mntonname[MNAMELEN];  /* directory on which mounted */
408 	char            f_mntfromname[MNAMELEN];/* mounted filesystem */
409 	char            f_reserved3;    /* For alignment */
410 	user32_long_t   f_reserved4[4]; /* For future use */
411 };
412 
413 /*
414  * throttle I/Os are affected only by normal I/Os happening on the same spindle.  Currently we use a 64-bit integer to
415  * represent what devices are affected, so we can handle at most 64 different spindles.  Since
416  * throttled I/O is usually useful in non-server environment only, this number is enough in most cases.
417  */
418 #define LOWPRI_MAX_NUM_DEV 64
419 
420 __BEGIN_DECLS
421 
422 extern uint32_t mount_generation;
423 extern TAILQ_HEAD(mntlist, mount) mountlist;
424 void mount_list_lock(void);
425 void mount_list_unlock(void);
426 void mount_lock_init(mount_t);
427 void mount_lock_destroy(mount_t);
428 void mount_lock(mount_t);
429 void mount_lock_spin(mount_t);
430 void mount_unlock(mount_t);
431 void mount_iterate_lock(mount_t);
432 void mount_iterate_unlock(mount_t);
433 void mount_lock_renames(mount_t);
434 void mount_unlock_renames(mount_t);
435 void mount_ref(mount_t, int);
436 void mount_drop(mount_t, int);
437 int  mount_refdrain(mount_t);
438 
439 /* vfs_rootmountalloc should be kept as a private api */
440 errno_t vfs_rootmountalloc(const char *, const char *, mount_t *mpp);
441 
442 int vfs_mount_recovery(void);
443 
444 typedef uint32_t vfs_switch_root_flags_t;
445 #define VFSSR_VIRTUALDEV_PROHIBITED     0x01 /* Not allowed to pivot into virtual devices (disk images).
446 	                                      * This is really just because we don't have a great way to find
447 	                                      * the filesystem that backs the image in order to set
448 	                                      * MNTK_BACKS_ROOT on it, which would prevent even forced-unmounts.
449 	                                      * Also, lots of disk images are backed by userspace processes,
450 	                                      * which also seems like a bad idea for the root filesystem. */
451 
452 int vfs_switch_root(const char *, const char *, vfs_switch_root_flags_t);
453 
454 int     vfs_mountroot(void);
455 void    vfs_unmountall(int only_non_system);
456 int     safedounmount(struct mount *, int, vfs_context_t);
457 int     dounmount(struct mount *, int, int, vfs_context_t);
458 void    dounmount_submounts(struct mount *, int, vfs_context_t);
459 
460 /* xnu internal api */
461 void  mount_dropcrossref(mount_t, vnode_t, int);
462 mount_t mount_lookupby_volfsid(int, int);
463 mount_t mount_list_lookupby_fsid(fsid_t *, int, int);
464 int  mount_list_add(mount_t);
465 void mount_list_remove(mount_t);
466 int  mount_iterref(mount_t, int);
467 int  mount_isdrained(mount_t, int);
468 void mount_iterdrop(mount_t);
469 void mount_iterdrain(mount_t);
470 void mount_iterreset(mount_t);
471 
472 /* These flags are used as flag bits in the `internal_flags` argument to mount_common */
473 /* Private NFS spi */
474 #define KERNEL_MOUNT_NOAUTH             0x01 /* Don't check the UID of the directory we are mounting on */
475 #define KERNEL_MOUNT_PERMIT_UNMOUNT     0x02 /* Allow (non-forced) unmounts by users other the one who mounted the volume */
476 /* used by snapshot mounting SPI */
477 #define KERNEL_MOUNT_SNAPSHOT           0x04 /* Mounting a snapshot */
478 #define KERNEL_MOUNT_DATAVOL            0x08 /* mount the data volume */
479 #define KERNEL_MOUNT_VMVOL              0x10 /* mount the VM volume */
480 #define KERNEL_MOUNT_PREBOOTVOL         0x20 /* mount the Preboot volume */
481 #define KERNEL_MOUNT_RECOVERYVOL        0x40 /* mount the Recovery volume */
482 #define KERNEL_MOUNT_BASESYSTEMROOT     0x80 /* mount a base root volume "instead of" the full root volume (only used during bsd_init) */
483 #define KERNEL_MOUNT_DEVFS             0x100 /* kernel startup mount of devfs */
484 #define KERNEL_MOUNT_FMOUNT            0x200 /* is fmount() system call */
485 #define KERNEL_MOUNT_KMOUNT            0x400 /* is kernel_mount() call */
486 
487 /* mask for checking if any of the "mount volume by role" flags are set */
488 #define KERNEL_MOUNT_VOLBYROLE_MASK (KERNEL_MOUNT_DATAVOL | KERNEL_MOUNT_VMVOL | KERNEL_MOUNT_PREBOOTVOL | KERNEL_MOUNT_RECOVERYVOL)
489 
490 /* mask for sanitizing inputs to kernel_mount() */
491 #define KERNEL_MOUNT_SANITIZE_MASK (~(KERNEL_MOUNT_FMOUNT))
492 
493 /*
494  * NOTE: kernel_mount() does not force MNT_NOSUID, MNT_NOEXEC, or MNT_NODEC for non-privileged
495  * mounting credentials, as the mount(2) system call does.
496  */
497 int kernel_mount(const char *, vnode_t, vnode_t, const char *, void *, size_t, int, uint32_t, vfs_context_t);
498 
499 /* Throttled I/O API.  KPI/SPI is in systm.h. */
500 
501 int  throttle_get_io_policy(struct uthread **ut);
502 int  throttle_get_passive_io_policy(struct uthread **ut);
503 void *throttle_info_update_by_mount(mount_t mp);
504 void rethrottle_thread(uthread_t ut);
505 
506 
507 /* throttled I/O helper function */
508 /* convert the lowest bit to a device index */
509 extern int num_trailing_0(uint64_t n);
510 
511 /* sync lock */
512 extern int sync_timeout_seconds;
513 
514 extern zone_t mount_zone;
515 
516 __END_DECLS
517 
518 #endif /* !_SYS_MOUNT_INTERNAL_H_ */
519