1/*
2 * Copyright (c) 2000-2016 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
89struct label;
90
91#if defined(__i386__) || defined(__x86_64__)
92typedef uint64_t pending_io_t;
93#define INCR_PENDING_IO(a, b) OSAddAtomic64((int64_t)(a), (int64_t *)&(b));
94#else
95typedef 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 */
105TAILQ_HEAD(vnodelst, vnode);
106
107struct 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 struct vfsops *mnt_op; /* operations on fs */
112 struct vfstable *mnt_vtable; /* configuration info */
113 struct vnode *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 */
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 struct label *mnt_fslabel; /* MAC default fs label */
162
163 /*
164 * cache the rootvp of the last mount point
165 * in the chain in the mount struct pointed
166 * to by the vnode sitting in '/'
167 * this cache is used to shortcircuit the
168 * mount chain traversal and allows us
169 * to traverse to the true underlying rootvp
170 * in 1 easy step inside of 'cache_lookup_path'
171 *
172 * make sure to validate against the cached vid
173 * in case the rootvp gets stolen away since
174 * we don't take an explicit long term reference
175 * on it when we mount it
176 */
177 vnode_t mnt_realrootvp;
178 uint32_t mnt_realrootvp_vid;
179 /*
180 * bumped each time a mount or unmount
181 * occurs... its used to invalidate
182 * 'mnt_realrootvp' from the cache
183 */
184 uint32_t mnt_generation;
185 /*
186 * if 'MNTK_AUTH_CACHE_TIMEOUT' is
187 * set, then 'mnt_authcache_ttl' is
188 * the time-to-live for the per-vnode authentication cache
189 * on this mount... if zero, no cache is maintained...
190 * if 'MNTK_AUTH_CACHE_TIMEOUT' isn't set, its the
191 * time-to-live for the cached lookup right for
192 * volumes marked 'MNTK_AUTH_OPAQUE'.
193 */
194 int mnt_authcache_ttl;
195 char fstypename_override[MFSTYPENAMELEN];
196
197 uint32_t mnt_iobufinuse;
198
199 void *mnt_disk_conditioner_info;
200
201 lck_mtx_t mnt_iter_lock; /* mutex that protects iteration of vnodes */
202};
203
204/*
205 * default number of seconds to keep cached lookup
206 * rights valid on mounts marked MNTK_AUTH_OPAQUE
207 */
208#define CACHED_LOOKUP_RIGHT_TTL 2
209
210/*
211 * ioflags
212 */
213#define MNT_IOFLAGS_FUA_SUPPORTED 0x00000001
214#define MNT_IOFLAGS_UNMAP_SUPPORTED 0x00000002
215#define MNT_IOFLAGS_IOSCHED_SUPPORTED 0x00000004
216#define MNT_IOFLAGS_CSUNMAP_SUPPORTED 0x00000008
217#define MNT_IOFLAGS_SWAPPIN_SUPPORTED 0x00000010
218#define MNT_IOFLAGS_FUSION_DRIVE 0x00000020
219
220/*
221 * ioqueue depth for devices that don't report one
222 */
223#define MNT_DEFAULT_IOQUEUE_DEPTH 32
224
225/*
226 * mnt_ioscale value for the given ioqueue depth
227 */
228#define MNT_IOSCALE(ioqueue_depth) ((ioqueue_depth + (MNT_DEFAULT_IOQUEUE_DEPTH - 1)) / MNT_DEFAULT_IOQUEUE_DEPTH)
229
230/* mount point to which dead vps point to */
231extern struct mount * dead_mountp;
232
233/*
234 * Internal filesystem control flags stored in mnt_kern_flag.
235 *
236 * MNTK_UNMOUNT locks the mount entry so that name lookup cannot proceed
237 * past the mount point. This keeps the subtree stable during mounts
238 * and unmounts.
239 *
240 * Note: We are counting down on new bit assignments. This is
241 * because the bits here were broken out from the high bits
242 * of the mount flags.
243 */
244#define MNTK_NOSWAP 0x00000080 /* swap files cannot be used on this mount */
245#define MNTK_SWAP_MOUNT 0x00000100 /* we are swapping to this mount */
246#define MNTK_DENY_READDIREXT 0x00000200 /* Deny Extended-style readdir's for this volume */
247#define MNTK_PERMIT_UNMOUNT 0x00000400 /* Allow (non-forced) unmounts by UIDs other than the one that mounted the volume */
248#ifdef NFSCLIENT
249#define MNTK_TYPENAME_OVERRIDE 0x00000800 /* override the fstypename for statfs() */
250#endif /* NFSCLIENT */
251#define MNTK_KERNEL_MOUNT 0x00001000 /* mount came from kernel side */
252#ifdef CONFIG_IMGSRC_ACCESS
253#define MNTK_HAS_MOVED 0x00002000
254#define MNTK_BACKS_ROOT 0x00004000
255#endif /* CONFIG_IMGSRC_ACCESS */
256#define MNTK_AUTH_CACHE_TTL 0x00008000 /* rights cache has TTL - TTL of 0 disables cache */
257#define MNTK_PATH_FROM_ID 0x00010000 /* mounted file system supports id-to-path lookups */
258#define MNTK_UNMOUNT_PREFLIGHT 0x00020000 /* mounted file system wants preflight check during unmount */
259#define MNTK_NAMED_STREAMS 0x00040000 /* mounted file system supports Named Streams VNOPs */
260#define MNTK_EXTENDED_ATTRS 0x00080000 /* mounted file system supports Extended Attributes VNOPs */
261#define MNTK_LOCK_LOCAL 0x00100000 /* advisory locking is done above the VFS itself */
262#define MNTK_VIRTUALDEV 0x00200000 /* mounted on a virtual device i.e. a disk image */
263#define MNTK_ROOTDEV 0x00400000 /* this filesystem resides on the same device as the root */
264#define MNTK_SSD 0x00800000 /* underlying device is of the solid state variety */
265#define MNTK_UNMOUNT 0x01000000 /* unmount in progress */
266#define MNTK_MWAIT 0x02000000 /* waiting for unmount to finish */
267#define MNTK_WANTRDWR 0x04000000 /* upgrade to read/write requested */
268#if REV_ENDIAN_FS
269#define MNT_REVEND 0x08000000 /* Reverse endian FS */
270#endif /* REV_ENDIAN_FS */
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#define MNT_LNOTRESP 0x00000001 /* mount not responding */
277#define MNT_LUNMOUNT 0x00000002 /* mount in unmount */
278#define MNT_LFORCE 0x00000004 /* mount in forced unmount */
279#define MNT_LDRAIN 0x00000008 /* mount in drain */
280#define MNT_LITER 0x00000010 /* mount in iteration */
281#define MNT_LNEWVN 0x00000020 /* mount has new vnodes created */
282#define MNT_LWAIT 0x00000040 /* wait for unmount op */
283#define MNT_LUNUSED 0x00000080 /* available flag bit, used to be MNT_LITERWAIT */
284#define MNT_LDEAD 0x00000100 /* mount already unmounted*/
285#define MNT_LNOSUB 0x00000200 /* submount - no recursion */
286
287
288/*
289 * Generic file handle
290 */
291#define NFS_MAX_FH_SIZE NFSV4_MAX_FH_SIZE
292#define NFSV4_MAX_FH_SIZE 128
293#define NFSV3_MAX_FH_SIZE 64
294#define NFSV2_MAX_FH_SIZE 32
295struct fhandle {
296 unsigned int fh_len; /* length of file handle */
297 unsigned char fh_data[NFS_MAX_FH_SIZE]; /* file handle value */
298};
299typedef struct fhandle fhandle_t;
300
301
302
303/*
304 * Filesystem configuration information. One of these exists for each
305 * type of filesystem supported by the kernel. These are searched at
306 * mount time to identify the requested filesystem.
307 */
308struct vfstable {
309 struct vfsops *vfc_vfsops; /* filesystem operations vector */
310 char vfc_name[MFSNAMELEN]; /* filesystem type name */
311 int vfc_typenum; /* historic filesystem type number */
312 int vfc_refcount; /* number mounted of this type */
313 int vfc_flags; /* permanent flags */
314 int (*vfc_mountroot)(mount_t, vnode_t, vfs_context_t); /* if != NULL, routine to mount root */
315 struct vfstable *vfc_next; /* next in list */
316 int32_t vfc_reserved1;
317 int32_t vfc_reserved2;
318 int vfc_vfsflags; /* for optional types */
319 void * vfc_descptr; /* desc table allocated address */
320 int vfc_descsize; /* size allocated for desc table */
321 struct sysctl_oid *vfc_sysctl; /* dynamically registered sysctl node */
322};
323
324/* vfc_vfsflags: */
325#define VFC_VFSLOCALARGS 0x002
326#define VFC_VFSGENERICARGS 0x004
327#define VFC_VFSNATIVEXATTR 0x010
328#define VFC_VFSCANMOUNTROOT 0x020
329#define VFC_VFSPREFLIGHT 0x040
330#define VFC_VFSREADDIR_EXTENDED 0x080
331#define VFC_VFS64BITREADY 0x100
332#define VFC_VFSNOMACLABEL 0x1000
333#define VFC_VFSVNOP_PAGEINV2 0x2000
334#define VFC_VFSVNOP_PAGEOUTV2 0x4000
335#define VFC_VFSVNOP_NOUPDATEID_RENAME 0x8000
336#define VFC_VFSVNOP_SECLUDE_RENAME 0x10000
337
338extern int maxvfstypenum; /* highest defined filesystem type */
339extern struct vfstable *vfsconf; /* head of list of filesystem types */
340extern const int maxvfsslots; /* Maximum statically allocated slots available to be used */
341extern int numused_vfsslots; /* number of statically allocated slots already used */
342extern int numregistered_fses; /* number of total registered filesystems */
343
344/* the following two are xnu private */
345struct vfstable * vfstable_add(struct vfstable *);
346int vfstable_del(struct vfstable *);
347
348
349struct vfsmount_args {
350 union {
351 struct {
352 char * mnt_fspec;
353 void * mnt_fsdata;
354 } mnt_localfs_args;
355 struct {
356 void * mnt_fsdata; /* FS specific */
357 } mnt_remotefs_args;
358 } mountfs_args;
359};
360
361
362/*
363 * LP64 *user* version of statfs structure.
364 * NOTE - must be kept in sync with struct statfs in mount.h
365 */
366struct user64_statfs {
367 short f_otype; /* TEMPORARY SHADOW COPY OF f_type */
368 short f_oflags; /* TEMPORARY SHADOW COPY OF f_flags */
369 user64_long_t f_bsize; /* fundamental file system block size */
370 user64_long_t f_iosize; /* optimal transfer block size */
371 user64_long_t f_blocks; /* total data blocks in file system */
372 user64_long_t f_bfree; /* free blocks in fs */
373 user64_long_t f_bavail; /* free blocks avail to non-superuser */
374 user64_long_t f_files; /* total file nodes in file system */
375 user64_long_t f_ffree; /* free file nodes in fs */
376 fsid_t f_fsid; /* file system id */
377 uid_t f_owner; /* user that mounted the filesystem */
378 short f_reserved1; /* spare for later */
379 short f_type; /* type of filesystem */
380 user64_long_t f_flags; /* copy of mount exported flags */
381 user64_long_t f_reserved2[2]; /* reserved for future use */
382 char f_fstypename[MFSNAMELEN]; /* fs type name */
383 char f_mntonname[MNAMELEN]; /* directory on which mounted */
384 char f_mntfromname[MNAMELEN];/* mounted filesystem */
385 char f_reserved3; /* For alignment */
386 user64_long_t f_reserved4[4]; /* For future use */
387};
388
389/*
390 * ILP32 *user* version of statfs structure.
391 * NOTE - must be kept in sync with struct statfs in mount.h
392 */
393struct user32_statfs {
394 short f_otype; /* TEMPORARY SHADOW COPY OF f_type */
395 short f_oflags; /* TEMPORARY SHADOW COPY OF f_flags */
396 user32_long_t f_bsize; /* fundamental file system block size */
397 user32_long_t f_iosize; /* optimal transfer block size */
398 user32_long_t f_blocks; /* total data blocks in file system */
399 user32_long_t f_bfree; /* free blocks in fs */
400 user32_long_t f_bavail; /* free blocks avail to non-superuser */
401 user32_long_t f_files; /* total file nodes in file system */
402 user32_long_t f_ffree; /* free file nodes in fs */
403 fsid_t f_fsid; /* file system id */
404 uid_t f_owner; /* user that mounted the filesystem */
405 short f_reserved1; /* spare for later */
406 short f_type; /* type of filesystem */
407 user32_long_t f_flags; /* copy of mount exported flags */
408 user32_long_t f_reserved2[2]; /* reserved for future use */
409 char f_fstypename[MFSNAMELEN]; /* fs type name */
410 char f_mntonname[MNAMELEN]; /* directory on which mounted */
411 char f_mntfromname[MNAMELEN];/* mounted filesystem */
412 char f_reserved3; /* For alignment */
413 user32_long_t f_reserved4[4]; /* For future use */
414};
415
416/*
417 * throttle I/Os are affected only by normal I/Os happening on the same spindle. Currently we use a 64-bit integer to
418 * represent what devices are affected, so we can handle at most 64 different spindles. Since
419 * throttled I/O is usually useful in non-server environment only, this number is enough in most cases.
420 */
421#define LOWPRI_MAX_NUM_DEV 64
422
423__BEGIN_DECLS
424
425extern uint32_t mount_generation;
426extern TAILQ_HEAD(mntlist, mount) mountlist;
427void mount_list_lock(void);
428void mount_list_unlock(void);
429void mount_lock_init(mount_t);
430void mount_lock_destroy(mount_t);
431void mount_lock(mount_t);
432void mount_lock_spin(mount_t);
433void mount_unlock(mount_t);
434void mount_iterate_lock(mount_t);
435void mount_iterate_unlock(mount_t);
436void mount_lock_renames(mount_t);
437void mount_unlock_renames(mount_t);
438void mount_ref(mount_t, int);
439void mount_drop(mount_t, int);
440int mount_refdrain(mount_t);
441
442/* vfs_rootmountalloc should be kept as a private api */
443errno_t vfs_rootmountalloc(const char *, const char *, mount_t *mpp);
444
445int vfs_mountroot(void);
446void vfs_unmountall(void);
447int safedounmount(struct mount *, int, vfs_context_t);
448int dounmount(struct mount *, int, int, vfs_context_t);
449void dounmount_submounts(struct mount *, int, vfs_context_t);
450
451/* xnu internal api */
452void mount_dropcrossref(mount_t, vnode_t, int);
453mount_t mount_lookupby_volfsid(int, int);
454mount_t mount_list_lookupby_fsid(fsid_t *, int, int);
455int mount_list_add(mount_t);
456void mount_list_remove(mount_t);
457int mount_iterref(mount_t, int);
458int mount_isdrained(mount_t, int);
459void mount_iterdrop(mount_t);
460void mount_iterdrain(mount_t);
461void mount_iterreset(mount_t);
462
463/* Private NFS spi */
464#define KERNEL_MOUNT_NOAUTH 0x01 /* Don't check the UID of the directory we are mounting on */
465#define KERNEL_MOUNT_PERMIT_UNMOUNT 0x02 /* Allow (non-forced) unmounts by users other the one who mounted the volume */
466/* used by snapshot mounting SPI */
467#define KERNEL_MOUNT_SNAPSHOT 0x04 /* Mounting a snapshot */
468#if NFSCLIENT || DEVFS || ROUTEFS
469/*
470 * NOTE: kernel_mount() does not force MNT_NOSUID, MNT_NOEXEC, or MNT_NODEC for non-privileged
471 * mounting credentials, as the mount(2) system call does.
472 */
473int kernel_mount(char *, vnode_t, vnode_t, const char *, void *, size_t, int, uint32_t, vfs_context_t);
474boolean_t vfs_iskernelmount(mount_t);
475#endif
476
477/* Throttled I/O API. KPI/SPI is in systm.h. */
478
479int throttle_get_io_policy(struct uthread **ut);
480int throttle_get_passive_io_policy(struct uthread **ut);
481void *throttle_info_update_by_mount(mount_t mp);
482void rethrottle_thread(uthread_t ut);
483
484
485/* throttled I/O helper function */
486/* convert the lowest bit to a device index */
487extern int num_trailing_0(uint64_t n);
488
489/* sync lock */
490extern lck_mtx_t * sync_mtx_lck;
491
492extern int sync_timeout_seconds;
493
494__END_DECLS
495
496#endif /* !_SYS_MOUNT_INTERNAL_H_ */
497