xref: /titanic_41/usr/src/uts/common/sys/vfs.h (revision 414388d7cb2ee98771e2ac7c2338c460abd44304)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*	Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T	*/
28 /*	  All Rights Reserved  	*/
29 
30 /*
31  * Portions of this source code were derived from Berkeley 4.3 BSD
32  * under license from the Regents of the University of California.
33  */
34 
35 #ifndef _SYS_VFS_H
36 #define	_SYS_VFS_H
37 
38 #pragma ident	"%Z%%M%	%I%	%E% SMI"
39 
40 #include <sys/types.h>
41 #include <sys/t_lock.h>
42 #include <sys/cred.h>
43 #include <sys/vnode.h>
44 #include <sys/statvfs.h>
45 #include <sys/refstr.h>
46 
47 #ifdef	__cplusplus
48 extern "C" {
49 #endif
50 
51 /*
52  * Data associated with mounted file systems.
53  */
54 
55 /*
56  * Operations vector.  This is used internal to the kernel; file systems
57  * supply their list of operations via vfs_setfsops().
58  */
59 
60 typedef struct vfsops vfsops_t;
61 
62 /*
63  * File system identifier. Should be unique (at least per machine).
64  */
65 typedef struct {
66 	int val[2];			/* file system id type */
67 } fsid_t;
68 
69 /*
70  * File identifier.  Should be unique per filesystem on a single
71  * machine.  This is typically called by a stateless file server
72  * in order to generate "file handles".
73  *
74  * Do not change the definition of struct fid ... fid_t without
75  * letting the CacheFS group know about it!  They will have to do at
76  * least two things, in the same change that changes this structure:
77  *   1. change CFSVERSION in usr/src/uts/common/sys/fs/cachefs_fs.h
78  *   2. put the old version # in the canupgrade array
79  *	in cachfs_upgrade() in usr/src/cmd/fs.d/cachefs/fsck/fsck.c
80  * This is necessary because CacheFS stores FIDs on disk.
81  *
82  * Many underlying file systems cast a struct fid into other
83  * file system dependent structures which may require 4 byte alignment.
84  * Because a fid starts with a short it may not be 4 byte aligned, the
85  * fid_pad will force the alignment.
86  */
87 #define	MAXFIDSZ	64
88 #define	OLD_MAXFIDSZ	16
89 
90 typedef struct fid {
91 	union {
92 		long fid_pad;
93 		struct {
94 			ushort_t len;	/* length of data in bytes */
95 			char	data[MAXFIDSZ]; /* data (variable len) */
96 		} _fid;
97 	} un;
98 } fid_t;
99 
100 #ifdef _SYSCALL32
101 /*
102  * Solaris 64 - use old-style cache format with 32-bit aligned fid for on-disk
103  * struct compatibility.
104  */
105 typedef struct fid32 {
106 	union {
107 		int32_t fid_pad;
108 		struct {
109 			uint16_t  len;   /* length of data in bytes */
110 			char    data[MAXFIDSZ]; /* data (variable len) */
111 		} _fid;
112 	} un;
113 } fid32_t;
114 #else /* not _SYSCALL32 */
115 #define	fid32	fid
116 typedef fid_t	fid32_t;
117 #endif /* _SYSCALL32 */
118 
119 #define	fid_len		un._fid.len
120 #define	fid_data	un._fid.data
121 
122 /*
123  * Structure defining a mount option for a filesystem.
124  * option names are found in mntent.h
125  */
126 typedef struct mntopt {
127 	char	*mo_name;	/* option name */
128 	char	**mo_cancel;	/* list of options cancelled by this one */
129 	char	*mo_arg;	/* argument string for this option */
130 	int	mo_flags;	/* flags for this mount option */
131 	void	*mo_data;	/* filesystem specific data */
132 } mntopt_t;
133 
134 /*
135  * Flags that apply to mount options
136  */
137 
138 #define	MO_SET		0x01		/* option is set */
139 #define	MO_NODISPLAY	0x02		/* option not listed in mnttab */
140 #define	MO_HASVALUE	0x04		/* option takes a value */
141 #define	MO_IGNORE	0x08		/* option ignored by parser */
142 #define	MO_DEFAULT	MO_SET		/* option is on by default */
143 #define	MO_TAG		0x10		/* flags a tag set by user program */
144 #define	MO_EMPTY	0x20		/* empty space in option table */
145 
146 #define	VFS_NOFORCEOPT	0x01		/* honor MO_IGNORE (don't set option) */
147 #define	VFS_DISPLAY	0x02		/* Turn off MO_NODISPLAY bit for opt */
148 #define	VFS_NODISPLAY	0x04		/* Turn on MO_NODISPLAY bit for opt */
149 #define	VFS_CREATEOPT	0x08		/* Create the opt if it's not there */
150 
151 /*
152  * Structure holding mount option strings for the mounted file system.
153  */
154 typedef struct mntopts {
155 	uint_t		mo_count;		/* number of entries in table */
156 	mntopt_t	*mo_list;		/* list of mount options */
157 } mntopts_t;
158 
159 /*
160  * Structure per mounted file system.  Each mounted file system has
161  * an array of operations and an instance record.
162  *
163  * The file systems are kept on a doubly linked circular list headed by
164  * "rootvfs".
165  * File system implementations should not access this list;
166  * it's intended for use only in the kernel's vfs layer.
167  *
168  * Each zone also has its own list of mounts, containing filesystems mounted
169  * somewhere within the filesystem tree rooted at the zone's rootpath.  The
170  * list is doubly linked to match the global list.
171  *
172  * mnttab locking: the in-kernel mnttab uses the vfs_mntpt, vfs_resource and
173  * vfs_mntopts fields in the vfs_t. mntpt and resource are refstr_ts that
174  * are set at mount time and can only be modified during a remount.
175  * It is safe to read these fields if you can prevent a remount on the vfs,
176  * or through the convenience funcs vfs_getmntpoint() and vfs_getresource().
177  * The mntopts field may only be accessed through the provided convenience
178  * functions, as it is protected by the vfs list lock. Modifying a mount
179  * option requires grabbing the vfs list write lock, which can be a very
180  * high latency lock.
181  */
182 struct zone;		/* from zone.h */
183 struct fem_head;	/* from fem.h */
184 
185 typedef struct vfs {
186 	struct vfs	*vfs_next;		/* next VFS in VFS list */
187 	struct vfs	*vfs_prev;		/* prev VFS in VFS list */
188 
189 /* vfs_op should not be used directly.  Accessor functions are provided */
190 	vfsops_t	*vfs_op;		/* operations on VFS */
191 
192 	struct vnode	*vfs_vnodecovered;	/* vnode mounted on */
193 	uint_t		vfs_flag;		/* flags */
194 	uint_t		vfs_bsize;		/* native block size */
195 	int		vfs_fstype;		/* file system type index */
196 	fsid_t		vfs_fsid;		/* file system id */
197 	void		*vfs_data;		/* private data */
198 	dev_t		vfs_dev;		/* device of mounted VFS */
199 	ulong_t		vfs_bcount;		/* I/O count (accounting) */
200 	struct vfs	*vfs_list;		/* sync list pointer */
201 	struct vfs	*vfs_hash;		/* hash list pointer */
202 	ksema_t		vfs_reflock;		/* mount/unmount/sync lock */
203 	uint_t		vfs_count;		/* vfs reference count */
204 	mntopts_t	vfs_mntopts;		/* options mounted with */
205 	refstr_t	*vfs_resource;		/* mounted resource name */
206 	refstr_t	*vfs_mntpt;		/* mount point name */
207 	time_t		vfs_mtime;		/* time we were mounted */
208 	struct fem_head	*vfs_femhead;		/* fs monitoring */
209 	/*
210 	 * Zones support.  Note that the zone that "owns" the mount isn't
211 	 * necessarily the same as the zone in which the zone is visible.
212 	 * That is, vfs_zone and (vfs_zone_next|vfs_zone_prev) may refer to
213 	 * different zones.
214 	 */
215 	struct zone	*vfs_zone;		/* zone that owns the mount */
216 	struct vfs	*vfs_zone_next;		/* next VFS visible in zone */
217 	struct vfs	*vfs_zone_prev;		/* prev VFS visible in zone */
218 } vfs_t;
219 
220 /*
221  * VFS flags.
222  */
223 #define	VFS_RDONLY	0x01		/* read-only vfs */
224 #define	VFS_NOMNTTAB	0x02		/* vfs not seen in mnttab */
225 #define	VFS_NOSETUID	0x08		/* setuid disallowed */
226 #define	VFS_REMOUNT	0x10		/* modify mount options only */
227 #define	VFS_NOTRUNC	0x20		/* does not truncate long file names */
228 #define	VFS_UNLINKABLE	0x40		/* unlink(2) can be applied to root */
229 #define	VFS_PXFS	0x80		/* clustering: global fs proxy vfs */
230 #define	VFS_UNMOUNTED	0x100		/* file system has been unmounted */
231 #define	VFS_NBMAND	0x200		/* allow non-blocking mandatory locks */
232 #define	VFS_XATTR	0x400		/* fs supports extended attributes */
233 #define	VFS_NODEVICES	0x800		/* device-special files disallowed */
234 #define	VFS_NOEXEC	0x1000		/* executables disallowed */
235 
236 #define	VFS_NORESOURCE	"unspecified_resource"
237 #define	VFS_NOMNTPT	"unspecified_mountpoint"
238 
239 /*
240  * Argument structure for mount(2).
241  *
242  * Flags are defined in <sys/mount.h>.
243  *
244  * Note that if the MS_SYSSPACE bit is set in flags, the pointer fields in
245  * this structure are to be interpreted as kernel addresses.  File systems
246  * should be prepared for this possibility.
247  */
248 struct mounta {
249 	char	*spec;
250 	char	*dir;
251 	int	flags;
252 	char	*fstype;
253 	char	*dataptr;
254 	int	datalen;
255 	char	*optptr;
256 	int	optlen;
257 };
258 
259 /*
260  * Reasons for calling the vfs_mountroot() operation.
261  */
262 enum whymountroot { ROOT_INIT, ROOT_REMOUNT, ROOT_UNMOUNT};
263 typedef enum whymountroot whymountroot_t;
264 
265 /*
266  * Reasons for calling the VFS_VNSTATE():
267  */
268 enum vntrans {
269 	VNTRANS_EXISTS,
270 	VNTRANS_IDLED,
271 	VNTRANS_RECLAIMED,
272 	VNTRANS_DESTROYED
273 };
274 typedef enum vntrans vntrans_t;
275 
276 
277 
278 
279 /*
280  * Operations supported on virtual file system.
281  */
282 struct vfsops {
283 	int	(*vfs_mount)(vfs_t *, vnode_t *, struct mounta *, cred_t *);
284 	int	(*vfs_unmount)(vfs_t *, int, cred_t *);
285 	int	(*vfs_root)(vfs_t *, vnode_t **);
286 	int	(*vfs_statvfs)(vfs_t *, statvfs64_t *);
287 	int	(*vfs_sync)(vfs_t *, short, cred_t *);
288 	int	(*vfs_vget)(vfs_t *, vnode_t **, fid_t *);
289 	int	(*vfs_mountroot)(vfs_t *, enum whymountroot);
290 	int	(*vfs_freevfs)(vfs_t *);
291 	int	(*vfs_vnstate)(vfs_t *, vnode_t *, vntrans_t);
292 };
293 
294 extern int	fsop_mount(vfs_t *, vnode_t *, struct mounta *, cred_t *);
295 extern int	fsop_unmount(vfs_t *, int, cred_t *);
296 extern int	fsop_root(vfs_t *, vnode_t **);
297 extern int	fsop_statfs(vfs_t *, statvfs64_t *);
298 extern int	fsop_sync(vfs_t *, short, cred_t *);
299 extern int	fsop_vget(vfs_t *, vnode_t **, fid_t *);
300 extern int	fsop_mountroot(vfs_t *, enum whymountroot);
301 extern void	fsop_freefs(vfs_t *);
302 extern int	fsop_sync_by_kind(int, short, cred_t *);
303 extern int	fsop_vnstate(vfs_t *, vnode_t *, vntrans_t);
304 
305 #define	VFS_MOUNT(vfsp, mvp, uap, cr) fsop_mount(vfsp, mvp, uap, cr)
306 #define	VFS_UNMOUNT(vfsp, flag, cr) fsop_unmount(vfsp, flag, cr)
307 #define	VFS_ROOT(vfsp, vpp) fsop_root(vfsp, vpp)
308 #define	VFS_STATVFS(vfsp, sp) fsop_statfs(vfsp, sp)
309 #define	VFS_SYNC(vfsp, flag, cr) fsop_sync(vfsp, flag, cr)
310 #define	VFS_VGET(vfsp, vpp, fidp) fsop_vget(vfsp, vpp, fidp)
311 #define	VFS_MOUNTROOT(vfsp, init) fsop_mountroot(vfsp, init)
312 #define	VFS_FREEVFS(vfsp) fsop_freefs(vfsp)
313 #define	VFS_VNSTATE(vfsp, vn, ns)	fsop_vnstate(vfsp, vn, ns)
314 
315 #define	VFSNAME_MOUNT		"mount"
316 #define	VFSNAME_UNMOUNT		"unmount"
317 #define	VFSNAME_ROOT		"root"
318 #define	VFSNAME_STATVFS		"statvfs"
319 #define	VFSNAME_SYNC		"sync"
320 #define	VFSNAME_VGET		"vget"
321 #define	VFSNAME_MOUNTROOT	"mountroot"
322 #define	VFSNAME_FREEVFS		"freevfs"
323 #define	VFSNAME_VNSTATE		"vnstate"
324 /*
325  * Filesystem type switch table.
326  */
327 
328 typedef struct vfssw {
329 	char		*vsw_name;	/* type name -- max len _ST_FSTYPSZ */
330 	int		(*vsw_init) (int, char *);
331 				/* init routine (for non-loadable fs only) */
332 	int		vsw_flag;	/* flags */
333 	mntopts_t	vsw_optproto;	/* mount options table prototype */
334 	uint_t		vsw_count;	/* count of references */
335 	kmutex_t	vsw_lock;	/* lock to protect vsw_count */
336 	vfsops_t	vsw_vfsops;	/* filesystem operations vector */
337 } vfssw_t;
338 
339 /*
340  * Filesystem type definition record.  All file systems must export a record
341  * of this type through their modlfs structure.
342  */
343 
344 typedef struct vfsdef_v3 {
345 	int		def_version;	/* structure version, must be first */
346 	char		*name;		/* filesystem type name */
347 	int		(*init) (int, char *);	/* init routine */
348 	int		flags;		/* filesystem flags */
349 	mntopts_t	*optproto;	/* mount options table prototype */
350 } vfsdef_v3;
351 
352 typedef struct vfsdef_v3 vfsdef_t;
353 
354 enum {
355 	VFSDEF_VERSION = 3
356 };
357 
358 /*
359  * Generic operations vector types (used for vfs/vnode ops registration).
360  */
361 
362 extern int fs_default();		/* "default" function placeholder */
363 extern int fs_error();			/* "error" function placeholder */
364 
365 int fs_build_vector(void *vector, int *unused_ops,
366     const fs_operation_trans_def_t *translation,
367     const fs_operation_def_t *operations);
368 
369 /*
370  * flags for vfssw and vfsdef
371  */
372 #define	VSW_HASPROTO	0x01	/* struct has a mount options prototype */
373 #define	VSW_CANRWRO	0x02	/* file system can transition from rw to ro */
374 #define	VSW_CANREMOUNT	0x04	/* file system supports remounts */
375 #define	VSW_NOTZONESAFE	0x08	/* zone_enter(2) should fail for these files */
376 #define	VSW_VOLATILEDEV	0x10	/* vfs_dev can change each time fs is mounted */
377 
378 #define	VSW_INSTALLED	0x8000	/* this vsw is associated with a file system */
379 
380 #if defined(_KERNEL)
381 /*
382  * Public operations.
383  */
384 struct umounta;
385 struct statvfsa;
386 struct fstatvfsa;
387 
388 int	vfs_setfsops(int, const fs_operation_def_t *, vfsops_t **);
389 int	vfs_makefsops(const fs_operation_def_t *, vfsops_t **);
390 void	vfs_freevfsops(vfsops_t *);
391 int	vfs_freevfsops_by_type(int);
392 void	vfs_setops(vfs_t *, vfsops_t *);
393 vfsops_t *vfs_getops(vfs_t *vfsp);
394 int	vfs_matchops(vfs_t *, vfsops_t *);
395 int	vfs_can_sync(vfs_t *vfsp);
396 void	vfs_init(vfs_t *vfsp, vfsops_t *, void *);
397 void	vn_exists(vnode_t *);
398 void	vn_idle(vnode_t *);
399 void	vn_reclaim(vnode_t *);
400 void	vn_invalid(vnode_t *);
401 
402 int	rootconf(void);
403 int	svm_rootconf(void);
404 int	domount(char *, struct mounta *, vnode_t *, struct cred *,
405 	    struct vfs **);
406 int	dounmount(struct vfs *, int, cred_t *);
407 int	vfs_lock(struct vfs *);
408 int	vfs_rlock(struct vfs *);
409 void	vfs_lock_wait(struct vfs *);
410 void	vfs_rlock_wait(struct vfs *);
411 void	vfs_unlock(struct vfs *);
412 int	vfs_lock_held(struct vfs *);
413 struct	_kthread *vfs_lock_owner(struct vfs *);
414 void	sync(void);
415 void	vfs_sync(int);
416 void	vfs_mountroot(void);
417 void	vfs_add(vnode_t *, struct vfs *, int);
418 void	vfs_remove(struct vfs *);
419 
420 /* The following functions are not for general use by filesystems */
421 
422 void	vfs_createopttbl(mntopts_t *, const char *);
423 void	vfs_copyopttbl(const mntopts_t *, mntopts_t *);
424 void	vfs_mergeopttbl(const mntopts_t *, const mntopts_t *, mntopts_t *);
425 void	vfs_freeopttbl(mntopts_t *);
426 void	vfs_parsemntopts(mntopts_t *, char *, int);
427 int	vfs_buildoptionstr(const mntopts_t *, char *, int);
428 struct mntopt *vfs_hasopt(const mntopts_t *, const char *);
429 void	vfs_mnttab_modtimeupd(void);
430 
431 void	vfs_clearmntopt(struct vfs *, const char *);
432 void	vfs_setmntopt(struct vfs *, const char *, const char *, int);
433 void	vfs_setresource(struct vfs *, const char *);
434 void	vfs_setmntpoint(struct vfs *, const char *);
435 refstr_t *vfs_getresource(const struct vfs *);
436 refstr_t *vfs_getmntpoint(const struct vfs *);
437 int	vfs_optionisset(const struct vfs *, const char *, char **);
438 int	vfs_settag(uint_t, uint_t, const char *, const char *, cred_t *);
439 int	vfs_clrtag(uint_t, uint_t, const char *, const char *, cred_t *);
440 void	vfs_syncall(void);
441 void	vfs_syncprogress(void);
442 void	vfsinit(void);
443 void	vfs_unmountall(void);
444 void	vfs_make_fsid(fsid_t *, dev_t, int);
445 void	vfs_addmip(dev_t, struct vfs *);
446 void	vfs_delmip(struct vfs *);
447 int	vfs_devismounted(dev_t);
448 int	vfs_devmounting(dev_t, struct vfs *);
449 int	vfs_opsinuse(vfsops_t *);
450 struct vfs *getvfs(fsid_t *);
451 struct vfs *vfs_dev2vfsp(dev_t);
452 struct vfs *vfs_mntpoint2vfsp(const char *);
453 struct vfssw *allocate_vfssw(char *);
454 struct vfssw *vfs_getvfssw(char *);
455 struct vfssw *vfs_getvfsswbyname(char *);
456 struct vfssw *vfs_getvfsswbyvfsops(vfsops_t *);
457 void	vfs_refvfssw(struct vfssw *);
458 void	vfs_unrefvfssw(struct vfssw *);
459 uint_t	vf_to_stf(uint_t);
460 void	vfs_mnttab_modtime(timespec_t *);
461 void	vfs_mnttab_poll(timespec_t *, struct pollhead **);
462 
463 void	vfs_list_lock(void);
464 void	vfs_list_read_lock(void);
465 void	vfs_list_unlock(void);
466 void	vfs_list_add(struct vfs *);
467 void	vfs_list_remove(struct vfs *);
468 void	vfs_hold(vfs_t *vfsp);
469 void	vfs_rele(vfs_t *vfsp);
470 void	fs_freevfs(vfs_t *);
471 void	vfs_root_redev(vfs_t *vfsp, dev_t ndev, int fstype);
472 
473 int	vfs_zone_change_safe(vfs_t *);
474 
475 #define	VFSHASH(maj, min) (((int)((maj)+(min))) & (vfshsz - 1))
476 #define	VFS_ON_LIST(vfsp) \
477 	((vfsp)->vfs_next != (vfsp) && (vfsp)->vfs_next != NULL)
478 
479 /*
480  * Globals.
481  */
482 
483 extern struct vfssw vfssw[];		/* table of filesystem types */
484 extern krwlock_t vfssw_lock;
485 extern char rootfstype[];		/* name of root fstype */
486 extern const int nfstype;		/* # of elements in vfssw array */
487 extern vfsops_t *EIO_vfsops;		/* operations for vfs being torn-down */
488 
489 /*
490  * The following variables are private to the the kernel's vfs layer.  File
491  * system implementations should not access them.
492  */
493 extern struct vfs *rootvfs;		/* ptr to root vfs structure */
494 typedef struct {
495 	struct vfs *rvfs_head;		/* head vfs in chain */
496 	kmutex_t rvfs_lock;		/* mutex protecting this chain */
497 	uint32_t rvfs_len;		/* length of this chain */
498 } rvfs_t;
499 extern rvfs_t *rvfs_list;
500 extern int vfshsz;			/* # of elements in rvfs_head array */
501 extern const mntopts_t vfs_mntopts;	/* globally recognized options */
502 
503 #endif /* defined(_KERNEL) */
504 
505 #define	VFS_HOLD(vfsp) { \
506 	vfs_hold(vfsp); \
507 }
508 
509 #define	VFS_RELE(vfsp)	{ \
510 	vfs_rele(vfsp); \
511 }
512 
513 #define	VFS_INIT(vfsp, op, data)	vfs_init((vfsp), (op), (data))
514 
515 #define	_VFS_INIT(vfsp, op, data)	{ \
516 	(vfsp)->vfs_count = 0; \
517 	(vfsp)->vfs_next = vfsp; \
518 	(vfsp)->vfs_prev = vfsp; \
519 	(vfsp)->vfs_zone_next = vfsp; \
520 	(vfsp)->vfs_zone_prev = vfsp; \
521 	vfs_setops((vfsp), (op)); \
522 	(vfsp)->vfs_flag = 0; \
523 	(vfsp)->vfs_data = (data); \
524 	(vfsp)->vfs_resource = NULL; \
525 	(vfsp)->vfs_mntpt = NULL; \
526 	(vfsp)->vfs_mntopts.mo_count = 0; \
527 	(vfsp)->vfs_mntopts.mo_list = NULL; \
528 	(vfsp)->vfs_femhead = NULL; \
529 	(vfsp)->vfs_zone = NULL; \
530 	sema_init(&(vfsp)->vfs_reflock, 1, NULL, SEMA_DEFAULT, NULL); \
531 }
532 
533 #define	VFS_INSTALLED(vfsswp)	(((vfsswp)->vsw_flag & VSW_INSTALLED) != 0)
534 #define	ALLOCATED_VFSSW(vswp)		((vswp)->vsw_name[0] != '\0')
535 #define	RLOCK_VFSSW()			(rw_enter(&vfssw_lock, RW_READER))
536 #define	RUNLOCK_VFSSW()			(rw_exit(&vfssw_lock))
537 #define	WLOCK_VFSSW()			(rw_enter(&vfssw_lock, RW_WRITER))
538 #define	WUNLOCK_VFSSW()			(rw_exit(&vfssw_lock))
539 #define	VFSSW_LOCKED()			(RW_LOCK_HELD(&vfssw_lock))
540 #define	VFSSW_WRITE_LOCKED()		(RW_WRITE_HELD(&vfssw_lock))
541 /*
542  * VFS_SYNC flags.
543  */
544 #define	SYNC_ATTR	0x01		/* sync attributes only */
545 #define	SYNC_CLOSE	0x02		/* close open file */
546 #define	SYNC_ALL	0x04		/* force to sync all fs */
547 
548 #ifdef	__cplusplus
549 }
550 #endif
551 
552 #endif	/* _SYS_VFS_H */
553