xref: /linux-6.15/include/linux/fs.h (revision 25985edc)
1 #ifndef _LINUX_FS_H
2 #define _LINUX_FS_H
3 
4 /*
5  * This file has definitions for some important file table
6  * structures etc.
7  */
8 
9 #include <linux/limits.h>
10 #include <linux/ioctl.h>
11 #include <linux/blk_types.h>
12 #include <linux/types.h>
13 
14 /*
15  * It's silly to have NR_OPEN bigger than NR_FILE, but you can change
16  * the file limit at runtime and only root can increase the per-process
17  * nr_file rlimit, so it's safe to set up a ridiculously high absolute
18  * upper limit on files-per-process.
19  *
20  * Some programs (notably those using select()) may have to be
21  * recompiled to take full advantage of the new limits..
22  */
23 
24 /* Fixed constants first: */
25 #undef NR_OPEN
26 #define INR_OPEN 1024		/* Initial setting for nfile rlimits */
27 
28 #define BLOCK_SIZE_BITS 10
29 #define BLOCK_SIZE (1<<BLOCK_SIZE_BITS)
30 
31 #define SEEK_SET	0	/* seek relative to beginning of file */
32 #define SEEK_CUR	1	/* seek relative to current file position */
33 #define SEEK_END	2	/* seek relative to end of file */
34 #define SEEK_MAX	SEEK_END
35 
36 struct fstrim_range {
37 	__u64 start;
38 	__u64 len;
39 	__u64 minlen;
40 };
41 
42 /* And dynamically-tunable limits and defaults: */
43 struct files_stat_struct {
44 	unsigned long nr_files;		/* read only */
45 	unsigned long nr_free_files;	/* read only */
46 	unsigned long max_files;		/* tunable */
47 };
48 
49 struct inodes_stat_t {
50 	int nr_inodes;
51 	int nr_unused;
52 	int dummy[5];		/* padding for sysctl ABI compatibility */
53 };
54 
55 
56 #define NR_FILE  8192	/* this can well be larger on a larger system */
57 
58 #define MAY_EXEC 1
59 #define MAY_WRITE 2
60 #define MAY_READ 4
61 #define MAY_APPEND 8
62 #define MAY_ACCESS 16
63 #define MAY_OPEN 32
64 #define MAY_CHDIR 64
65 
66 /*
67  * flags in file.f_mode.  Note that FMODE_READ and FMODE_WRITE must correspond
68  * to O_WRONLY and O_RDWR via the strange trick in __dentry_open()
69  */
70 
71 /* file is open for reading */
72 #define FMODE_READ		((__force fmode_t)0x1)
73 /* file is open for writing */
74 #define FMODE_WRITE		((__force fmode_t)0x2)
75 /* file is seekable */
76 #define FMODE_LSEEK		((__force fmode_t)0x4)
77 /* file can be accessed using pread */
78 #define FMODE_PREAD		((__force fmode_t)0x8)
79 /* file can be accessed using pwrite */
80 #define FMODE_PWRITE		((__force fmode_t)0x10)
81 /* File is opened for execution with sys_execve / sys_uselib */
82 #define FMODE_EXEC		((__force fmode_t)0x20)
83 /* File is opened with O_NDELAY (only set for block devices) */
84 #define FMODE_NDELAY		((__force fmode_t)0x40)
85 /* File is opened with O_EXCL (only set for block devices) */
86 #define FMODE_EXCL		((__force fmode_t)0x80)
87 /* File is opened using open(.., 3, ..) and is writeable only for ioctls
88    (specialy hack for floppy.c) */
89 #define FMODE_WRITE_IOCTL	((__force fmode_t)0x100)
90 
91 /*
92  * Don't update ctime and mtime.
93  *
94  * Currently a special hack for the XFS open_by_handle ioctl, but we'll
95  * hopefully graduate it to a proper O_CMTIME flag supported by open(2) soon.
96  */
97 #define FMODE_NOCMTIME		((__force fmode_t)0x800)
98 
99 /* Expect random access pattern */
100 #define FMODE_RANDOM		((__force fmode_t)0x1000)
101 
102 /* File is huge (eg. /dev/kmem): treat loff_t as unsigned */
103 #define FMODE_UNSIGNED_OFFSET	((__force fmode_t)0x2000)
104 
105 /* File is opened with O_PATH; almost nothing can be done with it */
106 #define FMODE_PATH		((__force fmode_t)0x4000)
107 
108 /* File was opened by fanotify and shouldn't generate fanotify events */
109 #define FMODE_NONOTIFY		((__force fmode_t)0x1000000)
110 
111 /*
112  * The below are the various read and write types that we support. Some of
113  * them include behavioral modifiers that send information down to the
114  * block layer and IO scheduler. Terminology:
115  *
116  *	The block layer uses device plugging to defer IO a little bit, in
117  *	the hope that we will see more IO very shortly. This increases
118  *	coalescing of adjacent IO and thus reduces the number of IOs we
119  *	have to send to the device. It also allows for better queuing,
120  *	if the IO isn't mergeable. If the caller is going to be waiting
121  *	for the IO, then he must ensure that the device is unplugged so
122  *	that the IO is dispatched to the driver.
123  *
124  *	All IO is handled async in Linux. This is fine for background
125  *	writes, but for reads or writes that someone waits for completion
126  *	on, we want to notify the block layer and IO scheduler so that they
127  *	know about it. That allows them to make better scheduling
128  *	decisions. So when the below references 'sync' and 'async', it
129  *	is referencing this priority hint.
130  *
131  * With that in mind, the available types are:
132  *
133  * READ			A normal read operation. Device will be plugged.
134  * READ_SYNC		A synchronous read. Device is not plugged, caller can
135  *			immediately wait on this read without caring about
136  *			unplugging.
137  * READA		Used for read-ahead operations. Lower priority, and the
138  *			block layer could (in theory) choose to ignore this
139  *			request if it runs into resource problems.
140  * WRITE		A normal async write. Device will be plugged.
141  * WRITE_SYNC		Synchronous write. Identical to WRITE, but passes down
142  *			the hint that someone will be waiting on this IO
143  *			shortly. The write equivalent of READ_SYNC.
144  * WRITE_ODIRECT	Special case write for O_DIRECT only.
145  * WRITE_FLUSH		Like WRITE_SYNC but with preceding cache flush.
146  * WRITE_FUA		Like WRITE_SYNC but data is guaranteed to be on
147  *			non-volatile media on completion.
148  * WRITE_FLUSH_FUA	Combination of WRITE_FLUSH and FUA. The IO is preceded
149  *			by a cache flush and data is guaranteed to be on
150  *			non-volatile media on completion.
151  *
152  */
153 #define RW_MASK			REQ_WRITE
154 #define RWA_MASK		REQ_RAHEAD
155 
156 #define READ			0
157 #define WRITE			RW_MASK
158 #define READA			RWA_MASK
159 
160 #define READ_SYNC		(READ | REQ_SYNC)
161 #define READ_META		(READ | REQ_META)
162 #define WRITE_SYNC		(WRITE | REQ_SYNC | REQ_NOIDLE)
163 #define WRITE_ODIRECT		(WRITE | REQ_SYNC)
164 #define WRITE_META		(WRITE | REQ_META)
165 #define WRITE_FLUSH		(WRITE | REQ_SYNC | REQ_NOIDLE | REQ_FLUSH)
166 #define WRITE_FUA		(WRITE | REQ_SYNC | REQ_NOIDLE | REQ_FUA)
167 #define WRITE_FLUSH_FUA		(WRITE | REQ_SYNC | REQ_NOIDLE | REQ_FLUSH | REQ_FUA)
168 
169 #define SEL_IN		1
170 #define SEL_OUT		2
171 #define SEL_EX		4
172 
173 /* public flags for file_system_type */
174 #define FS_REQUIRES_DEV 1
175 #define FS_BINARY_MOUNTDATA 2
176 #define FS_HAS_SUBTYPE 4
177 #define FS_REVAL_DOT	16384	/* Check the paths ".", ".." for staleness */
178 #define FS_RENAME_DOES_D_MOVE	32768	/* FS will handle d_move()
179 					 * during rename() internally.
180 					 */
181 
182 /*
183  * These are the fs-independent mount-flags: up to 32 flags are supported
184  */
185 #define MS_RDONLY	 1	/* Mount read-only */
186 #define MS_NOSUID	 2	/* Ignore suid and sgid bits */
187 #define MS_NODEV	 4	/* Disallow access to device special files */
188 #define MS_NOEXEC	 8	/* Disallow program execution */
189 #define MS_SYNCHRONOUS	16	/* Writes are synced at once */
190 #define MS_REMOUNT	32	/* Alter flags of a mounted FS */
191 #define MS_MANDLOCK	64	/* Allow mandatory locks on an FS */
192 #define MS_DIRSYNC	128	/* Directory modifications are synchronous */
193 #define MS_NOATIME	1024	/* Do not update access times. */
194 #define MS_NODIRATIME	2048	/* Do not update directory access times */
195 #define MS_BIND		4096
196 #define MS_MOVE		8192
197 #define MS_REC		16384
198 #define MS_VERBOSE	32768	/* War is peace. Verbosity is silence.
199 				   MS_VERBOSE is deprecated. */
200 #define MS_SILENT	32768
201 #define MS_POSIXACL	(1<<16)	/* VFS does not apply the umask */
202 #define MS_UNBINDABLE	(1<<17)	/* change to unbindable */
203 #define MS_PRIVATE	(1<<18)	/* change to private */
204 #define MS_SLAVE	(1<<19)	/* change to slave */
205 #define MS_SHARED	(1<<20)	/* change to shared */
206 #define MS_RELATIME	(1<<21)	/* Update atime relative to mtime/ctime. */
207 #define MS_KERNMOUNT	(1<<22) /* this is a kern_mount call */
208 #define MS_I_VERSION	(1<<23) /* Update inode I_version field */
209 #define MS_STRICTATIME	(1<<24) /* Always perform atime updates */
210 #define MS_BORN		(1<<29)
211 #define MS_ACTIVE	(1<<30)
212 #define MS_NOUSER	(1<<31)
213 
214 /*
215  * Superblock flags that can be altered by MS_REMOUNT
216  */
217 #define MS_RMT_MASK	(MS_RDONLY|MS_SYNCHRONOUS|MS_MANDLOCK|MS_I_VERSION)
218 
219 /*
220  * Old magic mount flag and mask
221  */
222 #define MS_MGC_VAL 0xC0ED0000
223 #define MS_MGC_MSK 0xffff0000
224 
225 /* Inode flags - they have nothing to superblock flags now */
226 
227 #define S_SYNC		1	/* Writes are synced at once */
228 #define S_NOATIME	2	/* Do not update access times */
229 #define S_APPEND	4	/* Append-only file */
230 #define S_IMMUTABLE	8	/* Immutable file */
231 #define S_DEAD		16	/* removed, but still open directory */
232 #define S_NOQUOTA	32	/* Inode is not counted to quota */
233 #define S_DIRSYNC	64	/* Directory modifications are synchronous */
234 #define S_NOCMTIME	128	/* Do not update file c/mtime */
235 #define S_SWAPFILE	256	/* Do not truncate: swapon got its bmaps */
236 #define S_PRIVATE	512	/* Inode is fs-internal */
237 #define S_IMA		1024	/* Inode has an associated IMA struct */
238 #define S_AUTOMOUNT	2048	/* Automount/referral quasi-directory */
239 
240 /*
241  * Note that nosuid etc flags are inode-specific: setting some file-system
242  * flags just means all the inodes inherit those flags by default. It might be
243  * possible to override it selectively if you really wanted to with some
244  * ioctl() that is not currently implemented.
245  *
246  * Exception: MS_RDONLY is always applied to the entire file system.
247  *
248  * Unfortunately, it is possible to change a filesystems flags with it mounted
249  * with files in use.  This means that all of the inodes will not have their
250  * i_flags updated.  Hence, i_flags no longer inherit the superblock mount
251  * flags, so these have to be checked separately. -- [email protected]
252  */
253 #define __IS_FLG(inode,flg) ((inode)->i_sb->s_flags & (flg))
254 
255 #define IS_RDONLY(inode) ((inode)->i_sb->s_flags & MS_RDONLY)
256 #define IS_SYNC(inode)		(__IS_FLG(inode, MS_SYNCHRONOUS) || \
257 					((inode)->i_flags & S_SYNC))
258 #define IS_DIRSYNC(inode)	(__IS_FLG(inode, MS_SYNCHRONOUS|MS_DIRSYNC) || \
259 					((inode)->i_flags & (S_SYNC|S_DIRSYNC)))
260 #define IS_MANDLOCK(inode)	__IS_FLG(inode, MS_MANDLOCK)
261 #define IS_NOATIME(inode)   __IS_FLG(inode, MS_RDONLY|MS_NOATIME)
262 #define IS_I_VERSION(inode)   __IS_FLG(inode, MS_I_VERSION)
263 
264 #define IS_NOQUOTA(inode)	((inode)->i_flags & S_NOQUOTA)
265 #define IS_APPEND(inode)	((inode)->i_flags & S_APPEND)
266 #define IS_IMMUTABLE(inode)	((inode)->i_flags & S_IMMUTABLE)
267 #define IS_POSIXACL(inode)	__IS_FLG(inode, MS_POSIXACL)
268 
269 #define IS_DEADDIR(inode)	((inode)->i_flags & S_DEAD)
270 #define IS_NOCMTIME(inode)	((inode)->i_flags & S_NOCMTIME)
271 #define IS_SWAPFILE(inode)	((inode)->i_flags & S_SWAPFILE)
272 #define IS_PRIVATE(inode)	((inode)->i_flags & S_PRIVATE)
273 #define IS_IMA(inode)		((inode)->i_flags & S_IMA)
274 #define IS_AUTOMOUNT(inode)	((inode)->i_flags & S_AUTOMOUNT)
275 
276 /* the read-only stuff doesn't really belong here, but any other place is
277    probably as bad and I don't want to create yet another include file. */
278 
279 #define BLKROSET   _IO(0x12,93)	/* set device read-only (0 = read-write) */
280 #define BLKROGET   _IO(0x12,94)	/* get read-only status (0 = read_write) */
281 #define BLKRRPART  _IO(0x12,95)	/* re-read partition table */
282 #define BLKGETSIZE _IO(0x12,96)	/* return device size /512 (long *arg) */
283 #define BLKFLSBUF  _IO(0x12,97)	/* flush buffer cache */
284 #define BLKRASET   _IO(0x12,98)	/* set read ahead for block device */
285 #define BLKRAGET   _IO(0x12,99)	/* get current read ahead setting */
286 #define BLKFRASET  _IO(0x12,100)/* set filesystem (mm/filemap.c) read-ahead */
287 #define BLKFRAGET  _IO(0x12,101)/* get filesystem (mm/filemap.c) read-ahead */
288 #define BLKSECTSET _IO(0x12,102)/* set max sectors per request (ll_rw_blk.c) */
289 #define BLKSECTGET _IO(0x12,103)/* get max sectors per request (ll_rw_blk.c) */
290 #define BLKSSZGET  _IO(0x12,104)/* get block device sector size */
291 #if 0
292 #define BLKPG      _IO(0x12,105)/* See blkpg.h */
293 
294 /* Some people are morons.  Do not use sizeof! */
295 
296 #define BLKELVGET  _IOR(0x12,106,size_t)/* elevator get */
297 #define BLKELVSET  _IOW(0x12,107,size_t)/* elevator set */
298 /* This was here just to show that the number is taken -
299    probably all these _IO(0x12,*) ioctls should be moved to blkpg.h. */
300 #endif
301 /* A jump here: 108-111 have been used for various private purposes. */
302 #define BLKBSZGET  _IOR(0x12,112,size_t)
303 #define BLKBSZSET  _IOW(0x12,113,size_t)
304 #define BLKGETSIZE64 _IOR(0x12,114,size_t)	/* return device size in bytes (u64 *arg) */
305 #define BLKTRACESETUP _IOWR(0x12,115,struct blk_user_trace_setup)
306 #define BLKTRACESTART _IO(0x12,116)
307 #define BLKTRACESTOP _IO(0x12,117)
308 #define BLKTRACETEARDOWN _IO(0x12,118)
309 #define BLKDISCARD _IO(0x12,119)
310 #define BLKIOMIN _IO(0x12,120)
311 #define BLKIOOPT _IO(0x12,121)
312 #define BLKALIGNOFF _IO(0x12,122)
313 #define BLKPBSZGET _IO(0x12,123)
314 #define BLKDISCARDZEROES _IO(0x12,124)
315 #define BLKSECDISCARD _IO(0x12,125)
316 
317 #define BMAP_IOCTL 1		/* obsolete - kept for compatibility */
318 #define FIBMAP	   _IO(0x00,1)	/* bmap access */
319 #define FIGETBSZ   _IO(0x00,2)	/* get the block size used for bmap */
320 #define FIFREEZE	_IOWR('X', 119, int)	/* Freeze */
321 #define FITHAW		_IOWR('X', 120, int)	/* Thaw */
322 #define FITRIM		_IOWR('X', 121, struct fstrim_range)	/* Trim */
323 
324 #define	FS_IOC_GETFLAGS			_IOR('f', 1, long)
325 #define	FS_IOC_SETFLAGS			_IOW('f', 2, long)
326 #define	FS_IOC_GETVERSION		_IOR('v', 1, long)
327 #define	FS_IOC_SETVERSION		_IOW('v', 2, long)
328 #define FS_IOC_FIEMAP			_IOWR('f', 11, struct fiemap)
329 #define FS_IOC32_GETFLAGS		_IOR('f', 1, int)
330 #define FS_IOC32_SETFLAGS		_IOW('f', 2, int)
331 #define FS_IOC32_GETVERSION		_IOR('v', 1, int)
332 #define FS_IOC32_SETVERSION		_IOW('v', 2, int)
333 
334 /*
335  * Inode flags (FS_IOC_GETFLAGS / FS_IOC_SETFLAGS)
336  */
337 #define	FS_SECRM_FL			0x00000001 /* Secure deletion */
338 #define	FS_UNRM_FL			0x00000002 /* Undelete */
339 #define	FS_COMPR_FL			0x00000004 /* Compress file */
340 #define FS_SYNC_FL			0x00000008 /* Synchronous updates */
341 #define FS_IMMUTABLE_FL			0x00000010 /* Immutable file */
342 #define FS_APPEND_FL			0x00000020 /* writes to file may only append */
343 #define FS_NODUMP_FL			0x00000040 /* do not dump file */
344 #define FS_NOATIME_FL			0x00000080 /* do not update atime */
345 /* Reserved for compression usage... */
346 #define FS_DIRTY_FL			0x00000100
347 #define FS_COMPRBLK_FL			0x00000200 /* One or more compressed clusters */
348 #define FS_NOCOMP_FL			0x00000400 /* Don't compress */
349 #define FS_ECOMPR_FL			0x00000800 /* Compression error */
350 /* End compression flags --- maybe not all used */
351 #define FS_BTREE_FL			0x00001000 /* btree format dir */
352 #define FS_INDEX_FL			0x00001000 /* hash-indexed directory */
353 #define FS_IMAGIC_FL			0x00002000 /* AFS directory */
354 #define FS_JOURNAL_DATA_FL		0x00004000 /* Reserved for ext3 */
355 #define FS_NOTAIL_FL			0x00008000 /* file tail should not be merged */
356 #define FS_DIRSYNC_FL			0x00010000 /* dirsync behaviour (directories only) */
357 #define FS_TOPDIR_FL			0x00020000 /* Top of directory hierarchies*/
358 #define FS_EXTENT_FL			0x00080000 /* Extents */
359 #define FS_DIRECTIO_FL			0x00100000 /* Use direct i/o */
360 #define FS_NOCOW_FL			0x00800000 /* Do not cow file */
361 #define FS_COW_FL			0x02000000 /* Cow file */
362 #define FS_RESERVED_FL			0x80000000 /* reserved for ext2 lib */
363 
364 #define FS_FL_USER_VISIBLE		0x0003DFFF /* User visible flags */
365 #define FS_FL_USER_MODIFIABLE		0x000380FF /* User modifiable flags */
366 
367 
368 #define SYNC_FILE_RANGE_WAIT_BEFORE	1
369 #define SYNC_FILE_RANGE_WRITE		2
370 #define SYNC_FILE_RANGE_WAIT_AFTER	4
371 
372 #ifdef __KERNEL__
373 
374 #include <linux/linkage.h>
375 #include <linux/wait.h>
376 #include <linux/types.h>
377 #include <linux/kdev_t.h>
378 #include <linux/dcache.h>
379 #include <linux/path.h>
380 #include <linux/stat.h>
381 #include <linux/cache.h>
382 #include <linux/list.h>
383 #include <linux/radix-tree.h>
384 #include <linux/prio_tree.h>
385 #include <linux/init.h>
386 #include <linux/pid.h>
387 #include <linux/mutex.h>
388 #include <linux/capability.h>
389 #include <linux/semaphore.h>
390 #include <linux/fiemap.h>
391 #include <linux/rculist_bl.h>
392 
393 #include <asm/atomic.h>
394 #include <asm/byteorder.h>
395 
396 struct export_operations;
397 struct hd_geometry;
398 struct iovec;
399 struct nameidata;
400 struct kiocb;
401 struct kobject;
402 struct pipe_inode_info;
403 struct poll_table_struct;
404 struct kstatfs;
405 struct vm_area_struct;
406 struct vfsmount;
407 struct cred;
408 
409 extern void __init inode_init(void);
410 extern void __init inode_init_early(void);
411 extern void __init files_init(unsigned long);
412 
413 extern struct files_stat_struct files_stat;
414 extern unsigned long get_max_files(void);
415 extern int sysctl_nr_open;
416 extern struct inodes_stat_t inodes_stat;
417 extern int leases_enable, lease_break_time;
418 
419 struct buffer_head;
420 typedef int (get_block_t)(struct inode *inode, sector_t iblock,
421 			struct buffer_head *bh_result, int create);
422 typedef void (dio_iodone_t)(struct kiocb *iocb, loff_t offset,
423 			ssize_t bytes, void *private, int ret,
424 			bool is_async);
425 
426 /*
427  * Attribute flags.  These should be or-ed together to figure out what
428  * has been changed!
429  */
430 #define ATTR_MODE	(1 << 0)
431 #define ATTR_UID	(1 << 1)
432 #define ATTR_GID	(1 << 2)
433 #define ATTR_SIZE	(1 << 3)
434 #define ATTR_ATIME	(1 << 4)
435 #define ATTR_MTIME	(1 << 5)
436 #define ATTR_CTIME	(1 << 6)
437 #define ATTR_ATIME_SET	(1 << 7)
438 #define ATTR_MTIME_SET	(1 << 8)
439 #define ATTR_FORCE	(1 << 9) /* Not a change, but a change it */
440 #define ATTR_ATTR_FLAG	(1 << 10)
441 #define ATTR_KILL_SUID	(1 << 11)
442 #define ATTR_KILL_SGID	(1 << 12)
443 #define ATTR_FILE	(1 << 13)
444 #define ATTR_KILL_PRIV	(1 << 14)
445 #define ATTR_OPEN	(1 << 15) /* Truncating from open(O_TRUNC) */
446 #define ATTR_TIMES_SET	(1 << 16)
447 
448 /*
449  * This is the Inode Attributes structure, used for notify_change().  It
450  * uses the above definitions as flags, to know which values have changed.
451  * Also, in this manner, a Filesystem can look at only the values it cares
452  * about.  Basically, these are the attributes that the VFS layer can
453  * request to change from the FS layer.
454  *
455  * Derek Atkins <[email protected]> 94-10-20
456  */
457 struct iattr {
458 	unsigned int	ia_valid;
459 	umode_t		ia_mode;
460 	uid_t		ia_uid;
461 	gid_t		ia_gid;
462 	loff_t		ia_size;
463 	struct timespec	ia_atime;
464 	struct timespec	ia_mtime;
465 	struct timespec	ia_ctime;
466 
467 	/*
468 	 * Not an attribute, but an auxiliary info for filesystems wanting to
469 	 * implement an ftruncate() like method.  NOTE: filesystem should
470 	 * check for (ia_valid & ATTR_FILE), and not for (ia_file != NULL).
471 	 */
472 	struct file	*ia_file;
473 };
474 
475 /*
476  * Includes for diskquotas.
477  */
478 #include <linux/quota.h>
479 
480 /**
481  * enum positive_aop_returns - aop return codes with specific semantics
482  *
483  * @AOP_WRITEPAGE_ACTIVATE: Informs the caller that page writeback has
484  * 			    completed, that the page is still locked, and
485  * 			    should be considered active.  The VM uses this hint
486  * 			    to return the page to the active list -- it won't
487  * 			    be a candidate for writeback again in the near
488  * 			    future.  Other callers must be careful to unlock
489  * 			    the page if they get this return.  Returned by
490  * 			    writepage();
491  *
492  * @AOP_TRUNCATED_PAGE: The AOP method that was handed a locked page has
493  *  			unlocked it and the page might have been truncated.
494  *  			The caller should back up to acquiring a new page and
495  *  			trying again.  The aop will be taking reasonable
496  *  			precautions not to livelock.  If the caller held a page
497  *  			reference, it should drop it before retrying.  Returned
498  *  			by readpage().
499  *
500  * address_space_operation functions return these large constants to indicate
501  * special semantics to the caller.  These are much larger than the bytes in a
502  * page to allow for functions that return the number of bytes operated on in a
503  * given page.
504  */
505 
506 enum positive_aop_returns {
507 	AOP_WRITEPAGE_ACTIVATE	= 0x80000,
508 	AOP_TRUNCATED_PAGE	= 0x80001,
509 };
510 
511 #define AOP_FLAG_UNINTERRUPTIBLE	0x0001 /* will not do a short write */
512 #define AOP_FLAG_CONT_EXPAND		0x0002 /* called from cont_expand */
513 #define AOP_FLAG_NOFS			0x0004 /* used by filesystem to direct
514 						* helper code (eg buffer layer)
515 						* to clear GFP_FS from alloc */
516 
517 /*
518  * oh the beauties of C type declarations.
519  */
520 struct page;
521 struct address_space;
522 struct writeback_control;
523 
524 struct iov_iter {
525 	const struct iovec *iov;
526 	unsigned long nr_segs;
527 	size_t iov_offset;
528 	size_t count;
529 };
530 
531 size_t iov_iter_copy_from_user_atomic(struct page *page,
532 		struct iov_iter *i, unsigned long offset, size_t bytes);
533 size_t iov_iter_copy_from_user(struct page *page,
534 		struct iov_iter *i, unsigned long offset, size_t bytes);
535 void iov_iter_advance(struct iov_iter *i, size_t bytes);
536 int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes);
537 size_t iov_iter_single_seg_count(struct iov_iter *i);
538 
539 static inline void iov_iter_init(struct iov_iter *i,
540 			const struct iovec *iov, unsigned long nr_segs,
541 			size_t count, size_t written)
542 {
543 	i->iov = iov;
544 	i->nr_segs = nr_segs;
545 	i->iov_offset = 0;
546 	i->count = count + written;
547 
548 	iov_iter_advance(i, written);
549 }
550 
551 static inline size_t iov_iter_count(struct iov_iter *i)
552 {
553 	return i->count;
554 }
555 
556 /*
557  * "descriptor" for what we're up to with a read.
558  * This allows us to use the same read code yet
559  * have multiple different users of the data that
560  * we read from a file.
561  *
562  * The simplest case just copies the data to user
563  * mode.
564  */
565 typedef struct {
566 	size_t written;
567 	size_t count;
568 	union {
569 		char __user *buf;
570 		void *data;
571 	} arg;
572 	int error;
573 } read_descriptor_t;
574 
575 typedef int (*read_actor_t)(read_descriptor_t *, struct page *,
576 		unsigned long, unsigned long);
577 
578 struct address_space_operations {
579 	int (*writepage)(struct page *page, struct writeback_control *wbc);
580 	int (*readpage)(struct file *, struct page *);
581 
582 	/* Write back some dirty pages from this mapping. */
583 	int (*writepages)(struct address_space *, struct writeback_control *);
584 
585 	/* Set a page dirty.  Return true if this dirtied it */
586 	int (*set_page_dirty)(struct page *page);
587 
588 	int (*readpages)(struct file *filp, struct address_space *mapping,
589 			struct list_head *pages, unsigned nr_pages);
590 
591 	int (*write_begin)(struct file *, struct address_space *mapping,
592 				loff_t pos, unsigned len, unsigned flags,
593 				struct page **pagep, void **fsdata);
594 	int (*write_end)(struct file *, struct address_space *mapping,
595 				loff_t pos, unsigned len, unsigned copied,
596 				struct page *page, void *fsdata);
597 
598 	/* Unfortunately this kludge is needed for FIBMAP. Don't use it */
599 	sector_t (*bmap)(struct address_space *, sector_t);
600 	void (*invalidatepage) (struct page *, unsigned long);
601 	int (*releasepage) (struct page *, gfp_t);
602 	void (*freepage)(struct page *);
603 	ssize_t (*direct_IO)(int, struct kiocb *, const struct iovec *iov,
604 			loff_t offset, unsigned long nr_segs);
605 	int (*get_xip_mem)(struct address_space *, pgoff_t, int,
606 						void **, unsigned long *);
607 	/* migrate the contents of a page to the specified target */
608 	int (*migratepage) (struct address_space *,
609 			struct page *, struct page *);
610 	int (*launder_page) (struct page *);
611 	int (*is_partially_uptodate) (struct page *, read_descriptor_t *,
612 					unsigned long);
613 	int (*error_remove_page)(struct address_space *, struct page *);
614 };
615 
616 /*
617  * pagecache_write_begin/pagecache_write_end must be used by general code
618  * to write into the pagecache.
619  */
620 int pagecache_write_begin(struct file *, struct address_space *mapping,
621 				loff_t pos, unsigned len, unsigned flags,
622 				struct page **pagep, void **fsdata);
623 
624 int pagecache_write_end(struct file *, struct address_space *mapping,
625 				loff_t pos, unsigned len, unsigned copied,
626 				struct page *page, void *fsdata);
627 
628 struct backing_dev_info;
629 struct address_space {
630 	struct inode		*host;		/* owner: inode, block_device */
631 	struct radix_tree_root	page_tree;	/* radix tree of all pages */
632 	spinlock_t		tree_lock;	/* and lock protecting it */
633 	unsigned int		i_mmap_writable;/* count VM_SHARED mappings */
634 	struct prio_tree_root	i_mmap;		/* tree of private and shared mappings */
635 	struct list_head	i_mmap_nonlinear;/*list VM_NONLINEAR mappings */
636 	spinlock_t		i_mmap_lock;	/* protect tree, count, list */
637 	unsigned int		truncate_count;	/* Cover race condition with truncate */
638 	unsigned long		nrpages;	/* number of total pages */
639 	pgoff_t			writeback_index;/* writeback starts here */
640 	const struct address_space_operations *a_ops;	/* methods */
641 	unsigned long		flags;		/* error bits/gfp mask */
642 	struct backing_dev_info *backing_dev_info; /* device readahead, etc */
643 	spinlock_t		private_lock;	/* for use by the address_space */
644 	struct list_head	private_list;	/* ditto */
645 	struct address_space	*assoc_mapping;	/* ditto */
646 	struct mutex		unmap_mutex;    /* to protect unmapping */
647 } __attribute__((aligned(sizeof(long))));
648 	/*
649 	 * On most architectures that alignment is already the case; but
650 	 * must be enforced here for CRIS, to let the least significant bit
651 	 * of struct page's "mapping" pointer be used for PAGE_MAPPING_ANON.
652 	 */
653 
654 struct block_device {
655 	dev_t			bd_dev;  /* not a kdev_t - it's a search key */
656 	int			bd_openers;
657 	struct inode *		bd_inode;	/* will die */
658 	struct super_block *	bd_super;
659 	struct mutex		bd_mutex;	/* open/close mutex */
660 	struct list_head	bd_inodes;
661 	void *			bd_claiming;
662 	void *			bd_holder;
663 	int			bd_holders;
664 	bool			bd_write_holder;
665 #ifdef CONFIG_SYSFS
666 	struct list_head	bd_holder_disks;
667 #endif
668 	struct block_device *	bd_contains;
669 	unsigned		bd_block_size;
670 	struct hd_struct *	bd_part;
671 	/* number of times partitions within this device have been opened. */
672 	unsigned		bd_part_count;
673 	int			bd_invalidated;
674 	struct gendisk *	bd_disk;
675 	struct list_head	bd_list;
676 	/*
677 	 * Private data.  You must have bd_claim'ed the block_device
678 	 * to use this.  NOTE:  bd_claim allows an owner to claim
679 	 * the same device multiple times, the owner must take special
680 	 * care to not mess up bd_private for that case.
681 	 */
682 	unsigned long		bd_private;
683 
684 	/* The counter of freeze processes */
685 	int			bd_fsfreeze_count;
686 	/* Mutex for freeze */
687 	struct mutex		bd_fsfreeze_mutex;
688 };
689 
690 /*
691  * Radix-tree tags, for tagging dirty and writeback pages within the pagecache
692  * radix trees
693  */
694 #define PAGECACHE_TAG_DIRTY	0
695 #define PAGECACHE_TAG_WRITEBACK	1
696 #define PAGECACHE_TAG_TOWRITE	2
697 
698 int mapping_tagged(struct address_space *mapping, int tag);
699 
700 /*
701  * Might pages of this file be mapped into userspace?
702  */
703 static inline int mapping_mapped(struct address_space *mapping)
704 {
705 	return	!prio_tree_empty(&mapping->i_mmap) ||
706 		!list_empty(&mapping->i_mmap_nonlinear);
707 }
708 
709 /*
710  * Might pages of this file have been modified in userspace?
711  * Note that i_mmap_writable counts all VM_SHARED vmas: do_mmap_pgoff
712  * marks vma as VM_SHARED if it is shared, and the file was opened for
713  * writing i.e. vma may be mprotected writable even if now readonly.
714  */
715 static inline int mapping_writably_mapped(struct address_space *mapping)
716 {
717 	return mapping->i_mmap_writable != 0;
718 }
719 
720 /*
721  * Use sequence counter to get consistent i_size on 32-bit processors.
722  */
723 #if BITS_PER_LONG==32 && defined(CONFIG_SMP)
724 #include <linux/seqlock.h>
725 #define __NEED_I_SIZE_ORDERED
726 #define i_size_ordered_init(inode) seqcount_init(&inode->i_size_seqcount)
727 #else
728 #define i_size_ordered_init(inode) do { } while (0)
729 #endif
730 
731 struct posix_acl;
732 #define ACL_NOT_CACHED ((void *)(-1))
733 
734 struct inode {
735 	/* RCU path lookup touches following: */
736 	umode_t			i_mode;
737 	uid_t			i_uid;
738 	gid_t			i_gid;
739 	const struct inode_operations	*i_op;
740 	struct super_block	*i_sb;
741 
742 	spinlock_t		i_lock;	/* i_blocks, i_bytes, maybe i_size */
743 	unsigned int		i_flags;
744 	struct mutex		i_mutex;
745 
746 	unsigned long		i_state;
747 	unsigned long		dirtied_when;	/* jiffies of first dirtying */
748 
749 	struct hlist_node	i_hash;
750 	struct list_head	i_wb_list;	/* backing dev IO list */
751 	struct list_head	i_lru;		/* inode LRU list */
752 	struct list_head	i_sb_list;
753 	union {
754 		struct list_head	i_dentry;
755 		struct rcu_head		i_rcu;
756 	};
757 	unsigned long		i_ino;
758 	atomic_t		i_count;
759 	unsigned int		i_nlink;
760 	dev_t			i_rdev;
761 	unsigned int		i_blkbits;
762 	u64			i_version;
763 	loff_t			i_size;
764 #ifdef __NEED_I_SIZE_ORDERED
765 	seqcount_t		i_size_seqcount;
766 #endif
767 	struct timespec		i_atime;
768 	struct timespec		i_mtime;
769 	struct timespec		i_ctime;
770 	blkcnt_t		i_blocks;
771 	unsigned short          i_bytes;
772 	struct rw_semaphore	i_alloc_sem;
773 	const struct file_operations	*i_fop;	/* former ->i_op->default_file_ops */
774 	struct file_lock	*i_flock;
775 	struct address_space	*i_mapping;
776 	struct address_space	i_data;
777 #ifdef CONFIG_QUOTA
778 	struct dquot		*i_dquot[MAXQUOTAS];
779 #endif
780 	struct list_head	i_devices;
781 	union {
782 		struct pipe_inode_info	*i_pipe;
783 		struct block_device	*i_bdev;
784 		struct cdev		*i_cdev;
785 	};
786 
787 	__u32			i_generation;
788 
789 #ifdef CONFIG_FSNOTIFY
790 	__u32			i_fsnotify_mask; /* all events this inode cares about */
791 	struct hlist_head	i_fsnotify_marks;
792 #endif
793 
794 #ifdef CONFIG_IMA
795 	atomic_t		i_readcount; /* struct files open RO */
796 #endif
797 	atomic_t		i_writecount;
798 #ifdef CONFIG_SECURITY
799 	void			*i_security;
800 #endif
801 #ifdef CONFIG_FS_POSIX_ACL
802 	struct posix_acl	*i_acl;
803 	struct posix_acl	*i_default_acl;
804 #endif
805 	void			*i_private; /* fs or device private pointer */
806 };
807 
808 static inline int inode_unhashed(struct inode *inode)
809 {
810 	return hlist_unhashed(&inode->i_hash);
811 }
812 
813 /*
814  * inode->i_mutex nesting subclasses for the lock validator:
815  *
816  * 0: the object of the current VFS operation
817  * 1: parent
818  * 2: child/target
819  * 3: quota file
820  *
821  * The locking order between these classes is
822  * parent -> child -> normal -> xattr -> quota
823  */
824 enum inode_i_mutex_lock_class
825 {
826 	I_MUTEX_NORMAL,
827 	I_MUTEX_PARENT,
828 	I_MUTEX_CHILD,
829 	I_MUTEX_XATTR,
830 	I_MUTEX_QUOTA
831 };
832 
833 /*
834  * NOTE: in a 32bit arch with a preemptable kernel and
835  * an UP compile the i_size_read/write must be atomic
836  * with respect to the local cpu (unlike with preempt disabled),
837  * but they don't need to be atomic with respect to other cpus like in
838  * true SMP (so they need either to either locally disable irq around
839  * the read or for example on x86 they can be still implemented as a
840  * cmpxchg8b without the need of the lock prefix). For SMP compiles
841  * and 64bit archs it makes no difference if preempt is enabled or not.
842  */
843 static inline loff_t i_size_read(const struct inode *inode)
844 {
845 #if BITS_PER_LONG==32 && defined(CONFIG_SMP)
846 	loff_t i_size;
847 	unsigned int seq;
848 
849 	do {
850 		seq = read_seqcount_begin(&inode->i_size_seqcount);
851 		i_size = inode->i_size;
852 	} while (read_seqcount_retry(&inode->i_size_seqcount, seq));
853 	return i_size;
854 #elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPT)
855 	loff_t i_size;
856 
857 	preempt_disable();
858 	i_size = inode->i_size;
859 	preempt_enable();
860 	return i_size;
861 #else
862 	return inode->i_size;
863 #endif
864 }
865 
866 /*
867  * NOTE: unlike i_size_read(), i_size_write() does need locking around it
868  * (normally i_mutex), otherwise on 32bit/SMP an update of i_size_seqcount
869  * can be lost, resulting in subsequent i_size_read() calls spinning forever.
870  */
871 static inline void i_size_write(struct inode *inode, loff_t i_size)
872 {
873 #if BITS_PER_LONG==32 && defined(CONFIG_SMP)
874 	write_seqcount_begin(&inode->i_size_seqcount);
875 	inode->i_size = i_size;
876 	write_seqcount_end(&inode->i_size_seqcount);
877 #elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPT)
878 	preempt_disable();
879 	inode->i_size = i_size;
880 	preempt_enable();
881 #else
882 	inode->i_size = i_size;
883 #endif
884 }
885 
886 static inline unsigned iminor(const struct inode *inode)
887 {
888 	return MINOR(inode->i_rdev);
889 }
890 
891 static inline unsigned imajor(const struct inode *inode)
892 {
893 	return MAJOR(inode->i_rdev);
894 }
895 
896 extern struct block_device *I_BDEV(struct inode *inode);
897 
898 struct fown_struct {
899 	rwlock_t lock;          /* protects pid, uid, euid fields */
900 	struct pid *pid;	/* pid or -pgrp where SIGIO should be sent */
901 	enum pid_type pid_type;	/* Kind of process group SIGIO should be sent to */
902 	uid_t uid, euid;	/* uid/euid of process setting the owner */
903 	int signum;		/* posix.1b rt signal to be delivered on IO */
904 };
905 
906 /*
907  * Track a single file's readahead state
908  */
909 struct file_ra_state {
910 	pgoff_t start;			/* where readahead started */
911 	unsigned int size;		/* # of readahead pages */
912 	unsigned int async_size;	/* do asynchronous readahead when
913 					   there are only # of pages ahead */
914 
915 	unsigned int ra_pages;		/* Maximum readahead window */
916 	unsigned int mmap_miss;		/* Cache miss stat for mmap accesses */
917 	loff_t prev_pos;		/* Cache last read() position */
918 };
919 
920 /*
921  * Check if @index falls in the readahead windows.
922  */
923 static inline int ra_has_index(struct file_ra_state *ra, pgoff_t index)
924 {
925 	return (index >= ra->start &&
926 		index <  ra->start + ra->size);
927 }
928 
929 #define FILE_MNT_WRITE_TAKEN	1
930 #define FILE_MNT_WRITE_RELEASED	2
931 
932 struct file {
933 	/*
934 	 * fu_list becomes invalid after file_free is called and queued via
935 	 * fu_rcuhead for RCU freeing
936 	 */
937 	union {
938 		struct list_head	fu_list;
939 		struct rcu_head 	fu_rcuhead;
940 	} f_u;
941 	struct path		f_path;
942 #define f_dentry	f_path.dentry
943 #define f_vfsmnt	f_path.mnt
944 	const struct file_operations	*f_op;
945 	spinlock_t		f_lock;  /* f_ep_links, f_flags, no IRQ */
946 #ifdef CONFIG_SMP
947 	int			f_sb_list_cpu;
948 #endif
949 	atomic_long_t		f_count;
950 	unsigned int 		f_flags;
951 	fmode_t			f_mode;
952 	loff_t			f_pos;
953 	struct fown_struct	f_owner;
954 	const struct cred	*f_cred;
955 	struct file_ra_state	f_ra;
956 
957 	u64			f_version;
958 #ifdef CONFIG_SECURITY
959 	void			*f_security;
960 #endif
961 	/* needed for tty driver, and maybe others */
962 	void			*private_data;
963 
964 #ifdef CONFIG_EPOLL
965 	/* Used by fs/eventpoll.c to link all the hooks to this file */
966 	struct list_head	f_ep_links;
967 #endif /* #ifdef CONFIG_EPOLL */
968 	struct address_space	*f_mapping;
969 #ifdef CONFIG_DEBUG_WRITECOUNT
970 	unsigned long f_mnt_write_state;
971 #endif
972 };
973 
974 struct file_handle {
975 	__u32 handle_bytes;
976 	int handle_type;
977 	/* file identifier */
978 	unsigned char f_handle[0];
979 };
980 
981 #define get_file(x)	atomic_long_inc(&(x)->f_count)
982 #define fput_atomic(x)	atomic_long_add_unless(&(x)->f_count, -1, 1)
983 #define file_count(x)	atomic_long_read(&(x)->f_count)
984 
985 #ifdef CONFIG_DEBUG_WRITECOUNT
986 static inline void file_take_write(struct file *f)
987 {
988 	WARN_ON(f->f_mnt_write_state != 0);
989 	f->f_mnt_write_state = FILE_MNT_WRITE_TAKEN;
990 }
991 static inline void file_release_write(struct file *f)
992 {
993 	f->f_mnt_write_state |= FILE_MNT_WRITE_RELEASED;
994 }
995 static inline void file_reset_write(struct file *f)
996 {
997 	f->f_mnt_write_state = 0;
998 }
999 static inline void file_check_state(struct file *f)
1000 {
1001 	/*
1002 	 * At this point, either both or neither of these bits
1003 	 * should be set.
1004 	 */
1005 	WARN_ON(f->f_mnt_write_state == FILE_MNT_WRITE_TAKEN);
1006 	WARN_ON(f->f_mnt_write_state == FILE_MNT_WRITE_RELEASED);
1007 }
1008 static inline int file_check_writeable(struct file *f)
1009 {
1010 	if (f->f_mnt_write_state == FILE_MNT_WRITE_TAKEN)
1011 		return 0;
1012 	printk(KERN_WARNING "writeable file with no "
1013 			    "mnt_want_write()\n");
1014 	WARN_ON(1);
1015 	return -EINVAL;
1016 }
1017 #else /* !CONFIG_DEBUG_WRITECOUNT */
1018 static inline void file_take_write(struct file *filp) {}
1019 static inline void file_release_write(struct file *filp) {}
1020 static inline void file_reset_write(struct file *filp) {}
1021 static inline void file_check_state(struct file *filp) {}
1022 static inline int file_check_writeable(struct file *filp)
1023 {
1024 	return 0;
1025 }
1026 #endif /* CONFIG_DEBUG_WRITECOUNT */
1027 
1028 #define	MAX_NON_LFS	((1UL<<31) - 1)
1029 
1030 /* Page cache limit. The filesystems should put that into their s_maxbytes
1031    limits, otherwise bad things can happen in VM. */
1032 #if BITS_PER_LONG==32
1033 #define MAX_LFS_FILESIZE	(((u64)PAGE_CACHE_SIZE << (BITS_PER_LONG-1))-1)
1034 #elif BITS_PER_LONG==64
1035 #define MAX_LFS_FILESIZE 	0x7fffffffffffffffUL
1036 #endif
1037 
1038 #define FL_POSIX	1
1039 #define FL_FLOCK	2
1040 #define FL_ACCESS	8	/* not trying to lock, just looking */
1041 #define FL_EXISTS	16	/* when unlocking, test for existence */
1042 #define FL_LEASE	32	/* lease held on this file */
1043 #define FL_CLOSE	64	/* unlock on close */
1044 #define FL_SLEEP	128	/* A blocking lock */
1045 
1046 /*
1047  * Special return value from posix_lock_file() and vfs_lock_file() for
1048  * asynchronous locking.
1049  */
1050 #define FILE_LOCK_DEFERRED 1
1051 
1052 /*
1053  * The POSIX file lock owner is determined by
1054  * the "struct files_struct" in the thread group
1055  * (or NULL for no owner - BSD locks).
1056  *
1057  * Lockd stuffs a "host" pointer into this.
1058  */
1059 typedef struct files_struct *fl_owner_t;
1060 
1061 struct file_lock_operations {
1062 	void (*fl_copy_lock)(struct file_lock *, struct file_lock *);
1063 	void (*fl_release_private)(struct file_lock *);
1064 };
1065 
1066 struct lock_manager_operations {
1067 	int (*fl_compare_owner)(struct file_lock *, struct file_lock *);
1068 	void (*fl_notify)(struct file_lock *);	/* unblock callback */
1069 	int (*fl_grant)(struct file_lock *, struct file_lock *, int);
1070 	void (*fl_release_private)(struct file_lock *);
1071 	void (*fl_break)(struct file_lock *);
1072 	int (*fl_change)(struct file_lock **, int);
1073 };
1074 
1075 struct lock_manager {
1076 	struct list_head list;
1077 };
1078 
1079 void locks_start_grace(struct lock_manager *);
1080 void locks_end_grace(struct lock_manager *);
1081 int locks_in_grace(void);
1082 
1083 /* that will die - we need it for nfs_lock_info */
1084 #include <linux/nfs_fs_i.h>
1085 
1086 struct file_lock {
1087 	struct file_lock *fl_next;	/* singly linked list for this inode  */
1088 	struct list_head fl_link;	/* doubly linked list of all locks */
1089 	struct list_head fl_block;	/* circular list of blocked processes */
1090 	fl_owner_t fl_owner;
1091 	unsigned char fl_flags;
1092 	unsigned char fl_type;
1093 	unsigned int fl_pid;
1094 	struct pid *fl_nspid;
1095 	wait_queue_head_t fl_wait;
1096 	struct file *fl_file;
1097 	loff_t fl_start;
1098 	loff_t fl_end;
1099 
1100 	struct fasync_struct *	fl_fasync; /* for lease break notifications */
1101 	unsigned long fl_break_time;	/* for nonblocking lease breaks */
1102 
1103 	const struct file_lock_operations *fl_ops;	/* Callbacks for filesystems */
1104 	const struct lock_manager_operations *fl_lmops;	/* Callbacks for lockmanagers */
1105 	union {
1106 		struct nfs_lock_info	nfs_fl;
1107 		struct nfs4_lock_info	nfs4_fl;
1108 		struct {
1109 			struct list_head link;	/* link in AFS vnode's pending_locks list */
1110 			int state;		/* state of grant or error if -ve */
1111 		} afs;
1112 	} fl_u;
1113 };
1114 
1115 /* The following constant reflects the upper bound of the file/locking space */
1116 #ifndef OFFSET_MAX
1117 #define INT_LIMIT(x)	(~((x)1 << (sizeof(x)*8 - 1)))
1118 #define OFFSET_MAX	INT_LIMIT(loff_t)
1119 #define OFFT_OFFSET_MAX	INT_LIMIT(off_t)
1120 #endif
1121 
1122 #include <linux/fcntl.h>
1123 
1124 extern void send_sigio(struct fown_struct *fown, int fd, int band);
1125 
1126 #ifdef CONFIG_FILE_LOCKING
1127 extern int fcntl_getlk(struct file *, struct flock __user *);
1128 extern int fcntl_setlk(unsigned int, struct file *, unsigned int,
1129 			struct flock __user *);
1130 
1131 #if BITS_PER_LONG == 32
1132 extern int fcntl_getlk64(struct file *, struct flock64 __user *);
1133 extern int fcntl_setlk64(unsigned int, struct file *, unsigned int,
1134 			struct flock64 __user *);
1135 #endif
1136 
1137 extern int fcntl_setlease(unsigned int fd, struct file *filp, long arg);
1138 extern int fcntl_getlease(struct file *filp);
1139 
1140 /* fs/locks.c */
1141 void locks_free_lock(struct file_lock *fl);
1142 extern void locks_init_lock(struct file_lock *);
1143 extern struct file_lock * locks_alloc_lock(void);
1144 extern void locks_copy_lock(struct file_lock *, struct file_lock *);
1145 extern void __locks_copy_lock(struct file_lock *, const struct file_lock *);
1146 extern void locks_remove_posix(struct file *, fl_owner_t);
1147 extern void locks_remove_flock(struct file *);
1148 extern void locks_release_private(struct file_lock *);
1149 extern void posix_test_lock(struct file *, struct file_lock *);
1150 extern int posix_lock_file(struct file *, struct file_lock *, struct file_lock *);
1151 extern int posix_lock_file_wait(struct file *, struct file_lock *);
1152 extern int posix_unblock_lock(struct file *, struct file_lock *);
1153 extern int vfs_test_lock(struct file *, struct file_lock *);
1154 extern int vfs_lock_file(struct file *, unsigned int, struct file_lock *, struct file_lock *);
1155 extern int vfs_cancel_lock(struct file *filp, struct file_lock *fl);
1156 extern int flock_lock_file_wait(struct file *filp, struct file_lock *fl);
1157 extern int __break_lease(struct inode *inode, unsigned int flags);
1158 extern void lease_get_mtime(struct inode *, struct timespec *time);
1159 extern int generic_setlease(struct file *, long, struct file_lock **);
1160 extern int vfs_setlease(struct file *, long, struct file_lock **);
1161 extern int lease_modify(struct file_lock **, int);
1162 extern int lock_may_read(struct inode *, loff_t start, unsigned long count);
1163 extern int lock_may_write(struct inode *, loff_t start, unsigned long count);
1164 extern void lock_flocks(void);
1165 extern void unlock_flocks(void);
1166 #else /* !CONFIG_FILE_LOCKING */
1167 static inline int fcntl_getlk(struct file *file, struct flock __user *user)
1168 {
1169 	return -EINVAL;
1170 }
1171 
1172 static inline int fcntl_setlk(unsigned int fd, struct file *file,
1173 			      unsigned int cmd, struct flock __user *user)
1174 {
1175 	return -EACCES;
1176 }
1177 
1178 #if BITS_PER_LONG == 32
1179 static inline int fcntl_getlk64(struct file *file, struct flock64 __user *user)
1180 {
1181 	return -EINVAL;
1182 }
1183 
1184 static inline int fcntl_setlk64(unsigned int fd, struct file *file,
1185 				unsigned int cmd, struct flock64 __user *user)
1186 {
1187 	return -EACCES;
1188 }
1189 #endif
1190 static inline int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
1191 {
1192 	return 0;
1193 }
1194 
1195 static inline int fcntl_getlease(struct file *filp)
1196 {
1197 	return 0;
1198 }
1199 
1200 static inline void locks_init_lock(struct file_lock *fl)
1201 {
1202 	return;
1203 }
1204 
1205 static inline void __locks_copy_lock(struct file_lock *new, struct file_lock *fl)
1206 {
1207 	return;
1208 }
1209 
1210 static inline void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
1211 {
1212 	return;
1213 }
1214 
1215 static inline void locks_remove_posix(struct file *filp, fl_owner_t owner)
1216 {
1217 	return;
1218 }
1219 
1220 static inline void locks_remove_flock(struct file *filp)
1221 {
1222 	return;
1223 }
1224 
1225 static inline void posix_test_lock(struct file *filp, struct file_lock *fl)
1226 {
1227 	return;
1228 }
1229 
1230 static inline int posix_lock_file(struct file *filp, struct file_lock *fl,
1231 				  struct file_lock *conflock)
1232 {
1233 	return -ENOLCK;
1234 }
1235 
1236 static inline int posix_lock_file_wait(struct file *filp, struct file_lock *fl)
1237 {
1238 	return -ENOLCK;
1239 }
1240 
1241 static inline int posix_unblock_lock(struct file *filp,
1242 				     struct file_lock *waiter)
1243 {
1244 	return -ENOENT;
1245 }
1246 
1247 static inline int vfs_test_lock(struct file *filp, struct file_lock *fl)
1248 {
1249 	return 0;
1250 }
1251 
1252 static inline int vfs_lock_file(struct file *filp, unsigned int cmd,
1253 				struct file_lock *fl, struct file_lock *conf)
1254 {
1255 	return -ENOLCK;
1256 }
1257 
1258 static inline int vfs_cancel_lock(struct file *filp, struct file_lock *fl)
1259 {
1260 	return 0;
1261 }
1262 
1263 static inline int flock_lock_file_wait(struct file *filp,
1264 				       struct file_lock *request)
1265 {
1266 	return -ENOLCK;
1267 }
1268 
1269 static inline int __break_lease(struct inode *inode, unsigned int mode)
1270 {
1271 	return 0;
1272 }
1273 
1274 static inline void lease_get_mtime(struct inode *inode, struct timespec *time)
1275 {
1276 	return;
1277 }
1278 
1279 static inline int generic_setlease(struct file *filp, long arg,
1280 				    struct file_lock **flp)
1281 {
1282 	return -EINVAL;
1283 }
1284 
1285 static inline int vfs_setlease(struct file *filp, long arg,
1286 			       struct file_lock **lease)
1287 {
1288 	return -EINVAL;
1289 }
1290 
1291 static inline int lease_modify(struct file_lock **before, int arg)
1292 {
1293 	return -EINVAL;
1294 }
1295 
1296 static inline int lock_may_read(struct inode *inode, loff_t start,
1297 				unsigned long len)
1298 {
1299 	return 1;
1300 }
1301 
1302 static inline int lock_may_write(struct inode *inode, loff_t start,
1303 				 unsigned long len)
1304 {
1305 	return 1;
1306 }
1307 
1308 static inline void lock_flocks(void)
1309 {
1310 }
1311 
1312 static inline void unlock_flocks(void)
1313 {
1314 }
1315 
1316 #endif /* !CONFIG_FILE_LOCKING */
1317 
1318 
1319 struct fasync_struct {
1320 	spinlock_t		fa_lock;
1321 	int			magic;
1322 	int			fa_fd;
1323 	struct fasync_struct	*fa_next; /* singly linked list */
1324 	struct file		*fa_file;
1325 	struct rcu_head		fa_rcu;
1326 };
1327 
1328 #define FASYNC_MAGIC 0x4601
1329 
1330 /* SMP safe fasync helpers: */
1331 extern int fasync_helper(int, struct file *, int, struct fasync_struct **);
1332 extern struct fasync_struct *fasync_insert_entry(int, struct file *, struct fasync_struct **, struct fasync_struct *);
1333 extern int fasync_remove_entry(struct file *, struct fasync_struct **);
1334 extern struct fasync_struct *fasync_alloc(void);
1335 extern void fasync_free(struct fasync_struct *);
1336 
1337 /* can be called from interrupts */
1338 extern void kill_fasync(struct fasync_struct **, int, int);
1339 
1340 extern int __f_setown(struct file *filp, struct pid *, enum pid_type, int force);
1341 extern int f_setown(struct file *filp, unsigned long arg, int force);
1342 extern void f_delown(struct file *filp);
1343 extern pid_t f_getown(struct file *filp);
1344 extern int send_sigurg(struct fown_struct *fown);
1345 
1346 /*
1347  *	Umount options
1348  */
1349 
1350 #define MNT_FORCE	0x00000001	/* Attempt to forcibily umount */
1351 #define MNT_DETACH	0x00000002	/* Just detach from the tree */
1352 #define MNT_EXPIRE	0x00000004	/* Mark for expiry */
1353 #define UMOUNT_NOFOLLOW	0x00000008	/* Don't follow symlink on umount */
1354 #define UMOUNT_UNUSED	0x80000000	/* Flag guaranteed to be unused */
1355 
1356 extern struct list_head super_blocks;
1357 extern spinlock_t sb_lock;
1358 
1359 struct super_block {
1360 	struct list_head	s_list;		/* Keep this first */
1361 	dev_t			s_dev;		/* search index; _not_ kdev_t */
1362 	unsigned char		s_dirt;
1363 	unsigned char		s_blocksize_bits;
1364 	unsigned long		s_blocksize;
1365 	loff_t			s_maxbytes;	/* Max file size */
1366 	struct file_system_type	*s_type;
1367 	const struct super_operations	*s_op;
1368 	const struct dquot_operations	*dq_op;
1369 	const struct quotactl_ops	*s_qcop;
1370 	const struct export_operations *s_export_op;
1371 	unsigned long		s_flags;
1372 	unsigned long		s_magic;
1373 	struct dentry		*s_root;
1374 	struct rw_semaphore	s_umount;
1375 	struct mutex		s_lock;
1376 	int			s_count;
1377 	atomic_t		s_active;
1378 #ifdef CONFIG_SECURITY
1379 	void                    *s_security;
1380 #endif
1381 	const struct xattr_handler **s_xattr;
1382 
1383 	struct list_head	s_inodes;	/* all inodes */
1384 	struct hlist_bl_head	s_anon;		/* anonymous dentries for (nfs) exporting */
1385 #ifdef CONFIG_SMP
1386 	struct list_head __percpu *s_files;
1387 #else
1388 	struct list_head	s_files;
1389 #endif
1390 	/* s_dentry_lru, s_nr_dentry_unused protected by dcache.c lru locks */
1391 	struct list_head	s_dentry_lru;	/* unused dentry lru */
1392 	int			s_nr_dentry_unused;	/* # of dentry on lru */
1393 
1394 	struct block_device	*s_bdev;
1395 	struct backing_dev_info *s_bdi;
1396 	struct mtd_info		*s_mtd;
1397 	struct list_head	s_instances;
1398 	struct quota_info	s_dquot;	/* Diskquota specific options */
1399 
1400 	int			s_frozen;
1401 	wait_queue_head_t	s_wait_unfrozen;
1402 
1403 	char s_id[32];				/* Informational name */
1404 	u8 s_uuid[16];				/* UUID */
1405 
1406 	void 			*s_fs_info;	/* Filesystem private info */
1407 	fmode_t			s_mode;
1408 
1409 	/* Granularity of c/m/atime in ns.
1410 	   Cannot be worse than a second */
1411 	u32		   s_time_gran;
1412 
1413 	/*
1414 	 * The next field is for VFS *only*. No filesystems have any business
1415 	 * even looking at it. You had been warned.
1416 	 */
1417 	struct mutex s_vfs_rename_mutex;	/* Kludge */
1418 
1419 	/*
1420 	 * Filesystem subtype.  If non-empty the filesystem type field
1421 	 * in /proc/mounts will be "type.subtype"
1422 	 */
1423 	char *s_subtype;
1424 
1425 	/*
1426 	 * Saved mount options for lazy filesystems using
1427 	 * generic_show_options()
1428 	 */
1429 	char __rcu *s_options;
1430 	const struct dentry_operations *s_d_op; /* default d_op for dentries */
1431 };
1432 
1433 extern struct timespec current_fs_time(struct super_block *sb);
1434 
1435 /*
1436  * Snapshotting support.
1437  */
1438 enum {
1439 	SB_UNFROZEN = 0,
1440 	SB_FREEZE_WRITE	= 1,
1441 	SB_FREEZE_TRANS = 2,
1442 };
1443 
1444 #define vfs_check_frozen(sb, level) \
1445 	wait_event((sb)->s_wait_unfrozen, ((sb)->s_frozen < (level)))
1446 
1447 #define get_fs_excl() atomic_inc(&current->fs_excl)
1448 #define put_fs_excl() atomic_dec(&current->fs_excl)
1449 #define has_fs_excl() atomic_read(&current->fs_excl)
1450 
1451 /*
1452  * until VFS tracks user namespaces for inodes, just make all files
1453  * belong to init_user_ns
1454  */
1455 extern struct user_namespace init_user_ns;
1456 #define inode_userns(inode) (&init_user_ns)
1457 extern bool inode_owner_or_capable(const struct inode *inode);
1458 
1459 /* not quite ready to be deprecated, but... */
1460 extern void lock_super(struct super_block *);
1461 extern void unlock_super(struct super_block *);
1462 
1463 /*
1464  * VFS helper functions..
1465  */
1466 extern int vfs_create(struct inode *, struct dentry *, int, struct nameidata *);
1467 extern int vfs_mkdir(struct inode *, struct dentry *, int);
1468 extern int vfs_mknod(struct inode *, struct dentry *, int, dev_t);
1469 extern int vfs_symlink(struct inode *, struct dentry *, const char *);
1470 extern int vfs_link(struct dentry *, struct inode *, struct dentry *);
1471 extern int vfs_rmdir(struct inode *, struct dentry *);
1472 extern int vfs_unlink(struct inode *, struct dentry *);
1473 extern int vfs_rename(struct inode *, struct dentry *, struct inode *, struct dentry *);
1474 
1475 /*
1476  * VFS dentry helper functions.
1477  */
1478 extern void dentry_unhash(struct dentry *dentry);
1479 
1480 /*
1481  * VFS file helper functions.
1482  */
1483 extern int file_permission(struct file *, int);
1484 extern void inode_init_owner(struct inode *inode, const struct inode *dir,
1485 			mode_t mode);
1486 /*
1487  * VFS FS_IOC_FIEMAP helper definitions.
1488  */
1489 struct fiemap_extent_info {
1490 	unsigned int fi_flags;		/* Flags as passed from user */
1491 	unsigned int fi_extents_mapped;	/* Number of mapped extents */
1492 	unsigned int fi_extents_max;	/* Size of fiemap_extent array */
1493 	struct fiemap_extent __user *fi_extents_start; /* Start of
1494 							fiemap_extent array */
1495 };
1496 int fiemap_fill_next_extent(struct fiemap_extent_info *info, u64 logical,
1497 			    u64 phys, u64 len, u32 flags);
1498 int fiemap_check_flags(struct fiemap_extent_info *fieinfo, u32 fs_flags);
1499 
1500 /*
1501  * File types
1502  *
1503  * NOTE! These match bits 12..15 of stat.st_mode
1504  * (ie "(i_mode >> 12) & 15").
1505  */
1506 #define DT_UNKNOWN	0
1507 #define DT_FIFO		1
1508 #define DT_CHR		2
1509 #define DT_DIR		4
1510 #define DT_BLK		6
1511 #define DT_REG		8
1512 #define DT_LNK		10
1513 #define DT_SOCK		12
1514 #define DT_WHT		14
1515 
1516 /*
1517  * This is the "filldir" function type, used by readdir() to let
1518  * the kernel specify what kind of dirent layout it wants to have.
1519  * This allows the kernel to read directories into kernel space or
1520  * to have different dirent layouts depending on the binary type.
1521  */
1522 typedef int (*filldir_t)(void *, const char *, int, loff_t, u64, unsigned);
1523 struct block_device_operations;
1524 
1525 /* These macros are for out of kernel modules to test that
1526  * the kernel supports the unlocked_ioctl and compat_ioctl
1527  * fields in struct file_operations. */
1528 #define HAVE_COMPAT_IOCTL 1
1529 #define HAVE_UNLOCKED_IOCTL 1
1530 
1531 /*
1532  * NOTE:
1533  * all file operations except setlease can be called without
1534  * the big kernel lock held in all filesystems.
1535  */
1536 struct file_operations {
1537 	struct module *owner;
1538 	loff_t (*llseek) (struct file *, loff_t, int);
1539 	ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);
1540 	ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
1541 	ssize_t (*aio_read) (struct kiocb *, const struct iovec *, unsigned long, loff_t);
1542 	ssize_t (*aio_write) (struct kiocb *, const struct iovec *, unsigned long, loff_t);
1543 	int (*readdir) (struct file *, void *, filldir_t);
1544 	unsigned int (*poll) (struct file *, struct poll_table_struct *);
1545 	long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
1546 	long (*compat_ioctl) (struct file *, unsigned int, unsigned long);
1547 	int (*mmap) (struct file *, struct vm_area_struct *);
1548 	int (*open) (struct inode *, struct file *);
1549 	int (*flush) (struct file *, fl_owner_t id);
1550 	int (*release) (struct inode *, struct file *);
1551 	int (*fsync) (struct file *, int datasync);
1552 	int (*aio_fsync) (struct kiocb *, int datasync);
1553 	int (*fasync) (int, struct file *, int);
1554 	int (*lock) (struct file *, int, struct file_lock *);
1555 	ssize_t (*sendpage) (struct file *, struct page *, int, size_t, loff_t *, int);
1556 	unsigned long (*get_unmapped_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
1557 	int (*check_flags)(int);
1558 	int (*flock) (struct file *, int, struct file_lock *);
1559 	ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, loff_t *, size_t, unsigned int);
1560 	ssize_t (*splice_read)(struct file *, loff_t *, struct pipe_inode_info *, size_t, unsigned int);
1561 	int (*setlease)(struct file *, long, struct file_lock **);
1562 	long (*fallocate)(struct file *file, int mode, loff_t offset,
1563 			  loff_t len);
1564 };
1565 
1566 #define IPERM_FLAG_RCU	0x0001
1567 
1568 struct inode_operations {
1569 	struct dentry * (*lookup) (struct inode *,struct dentry *, struct nameidata *);
1570 	void * (*follow_link) (struct dentry *, struct nameidata *);
1571 	int (*permission) (struct inode *, int, unsigned int);
1572 	int (*check_acl)(struct inode *, int, unsigned int);
1573 
1574 	int (*readlink) (struct dentry *, char __user *,int);
1575 	void (*put_link) (struct dentry *, struct nameidata *, void *);
1576 
1577 	int (*create) (struct inode *,struct dentry *,int, struct nameidata *);
1578 	int (*link) (struct dentry *,struct inode *,struct dentry *);
1579 	int (*unlink) (struct inode *,struct dentry *);
1580 	int (*symlink) (struct inode *,struct dentry *,const char *);
1581 	int (*mkdir) (struct inode *,struct dentry *,int);
1582 	int (*rmdir) (struct inode *,struct dentry *);
1583 	int (*mknod) (struct inode *,struct dentry *,int,dev_t);
1584 	int (*rename) (struct inode *, struct dentry *,
1585 			struct inode *, struct dentry *);
1586 	void (*truncate) (struct inode *);
1587 	int (*setattr) (struct dentry *, struct iattr *);
1588 	int (*getattr) (struct vfsmount *mnt, struct dentry *, struct kstat *);
1589 	int (*setxattr) (struct dentry *, const char *,const void *,size_t,int);
1590 	ssize_t (*getxattr) (struct dentry *, const char *, void *, size_t);
1591 	ssize_t (*listxattr) (struct dentry *, char *, size_t);
1592 	int (*removexattr) (struct dentry *, const char *);
1593 	void (*truncate_range)(struct inode *, loff_t, loff_t);
1594 	int (*fiemap)(struct inode *, struct fiemap_extent_info *, u64 start,
1595 		      u64 len);
1596 } ____cacheline_aligned;
1597 
1598 struct seq_file;
1599 
1600 ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector,
1601 				unsigned long nr_segs, unsigned long fast_segs,
1602 				struct iovec *fast_pointer,
1603 				struct iovec **ret_pointer);
1604 
1605 extern ssize_t vfs_read(struct file *, char __user *, size_t, loff_t *);
1606 extern ssize_t vfs_write(struct file *, const char __user *, size_t, loff_t *);
1607 extern ssize_t vfs_readv(struct file *, const struct iovec __user *,
1608 		unsigned long, loff_t *);
1609 extern ssize_t vfs_writev(struct file *, const struct iovec __user *,
1610 		unsigned long, loff_t *);
1611 
1612 struct super_operations {
1613    	struct inode *(*alloc_inode)(struct super_block *sb);
1614 	void (*destroy_inode)(struct inode *);
1615 
1616    	void (*dirty_inode) (struct inode *);
1617 	int (*write_inode) (struct inode *, struct writeback_control *wbc);
1618 	int (*drop_inode) (struct inode *);
1619 	void (*evict_inode) (struct inode *);
1620 	void (*put_super) (struct super_block *);
1621 	void (*write_super) (struct super_block *);
1622 	int (*sync_fs)(struct super_block *sb, int wait);
1623 	int (*freeze_fs) (struct super_block *);
1624 	int (*unfreeze_fs) (struct super_block *);
1625 	int (*statfs) (struct dentry *, struct kstatfs *);
1626 	int (*remount_fs) (struct super_block *, int *, char *);
1627 	void (*umount_begin) (struct super_block *);
1628 
1629 	int (*show_options)(struct seq_file *, struct vfsmount *);
1630 	int (*show_devname)(struct seq_file *, struct vfsmount *);
1631 	int (*show_path)(struct seq_file *, struct vfsmount *);
1632 	int (*show_stats)(struct seq_file *, struct vfsmount *);
1633 #ifdef CONFIG_QUOTA
1634 	ssize_t (*quota_read)(struct super_block *, int, char *, size_t, loff_t);
1635 	ssize_t (*quota_write)(struct super_block *, int, const char *, size_t, loff_t);
1636 #endif
1637 	int (*bdev_try_to_free_page)(struct super_block*, struct page*, gfp_t);
1638 };
1639 
1640 /*
1641  * Inode state bits.  Protected by inode->i_lock
1642  *
1643  * Three bits determine the dirty state of the inode, I_DIRTY_SYNC,
1644  * I_DIRTY_DATASYNC and I_DIRTY_PAGES.
1645  *
1646  * Four bits define the lifetime of an inode.  Initially, inodes are I_NEW,
1647  * until that flag is cleared.  I_WILL_FREE, I_FREEING and I_CLEAR are set at
1648  * various stages of removing an inode.
1649  *
1650  * Two bits are used for locking and completion notification, I_NEW and I_SYNC.
1651  *
1652  * I_DIRTY_SYNC		Inode is dirty, but doesn't have to be written on
1653  *			fdatasync().  i_atime is the usual cause.
1654  * I_DIRTY_DATASYNC	Data-related inode changes pending. We keep track of
1655  *			these changes separately from I_DIRTY_SYNC so that we
1656  *			don't have to write inode on fdatasync() when only
1657  *			mtime has changed in it.
1658  * I_DIRTY_PAGES	Inode has dirty pages.  Inode itself may be clean.
1659  * I_NEW		Serves as both a mutex and completion notification.
1660  *			New inodes set I_NEW.  If two processes both create
1661  *			the same inode, one of them will release its inode and
1662  *			wait for I_NEW to be released before returning.
1663  *			Inodes in I_WILL_FREE, I_FREEING or I_CLEAR state can
1664  *			also cause waiting on I_NEW, without I_NEW actually
1665  *			being set.  find_inode() uses this to prevent returning
1666  *			nearly-dead inodes.
1667  * I_WILL_FREE		Must be set when calling write_inode_now() if i_count
1668  *			is zero.  I_FREEING must be set when I_WILL_FREE is
1669  *			cleared.
1670  * I_FREEING		Set when inode is about to be freed but still has dirty
1671  *			pages or buffers attached or the inode itself is still
1672  *			dirty.
1673  * I_CLEAR		Added by end_writeback().  In this state the inode is clean
1674  *			and can be destroyed.  Inode keeps I_FREEING.
1675  *
1676  *			Inodes that are I_WILL_FREE, I_FREEING or I_CLEAR are
1677  *			prohibited for many purposes.  iget() must wait for
1678  *			the inode to be completely released, then create it
1679  *			anew.  Other functions will just ignore such inodes,
1680  *			if appropriate.  I_NEW is used for waiting.
1681  *
1682  * I_SYNC		Synchonized write of dirty inode data.  The bits is
1683  *			set during data writeback, and cleared with a wakeup
1684  *			on the bit address once it is done.
1685  *
1686  * Q: What is the difference between I_WILL_FREE and I_FREEING?
1687  */
1688 #define I_DIRTY_SYNC		(1 << 0)
1689 #define I_DIRTY_DATASYNC	(1 << 1)
1690 #define I_DIRTY_PAGES		(1 << 2)
1691 #define __I_NEW			3
1692 #define I_NEW			(1 << __I_NEW)
1693 #define I_WILL_FREE		(1 << 4)
1694 #define I_FREEING		(1 << 5)
1695 #define I_CLEAR			(1 << 6)
1696 #define __I_SYNC		7
1697 #define I_SYNC			(1 << __I_SYNC)
1698 #define I_REFERENCED		(1 << 8)
1699 
1700 #define I_DIRTY (I_DIRTY_SYNC | I_DIRTY_DATASYNC | I_DIRTY_PAGES)
1701 
1702 extern void __mark_inode_dirty(struct inode *, int);
1703 static inline void mark_inode_dirty(struct inode *inode)
1704 {
1705 	__mark_inode_dirty(inode, I_DIRTY);
1706 }
1707 
1708 static inline void mark_inode_dirty_sync(struct inode *inode)
1709 {
1710 	__mark_inode_dirty(inode, I_DIRTY_SYNC);
1711 }
1712 
1713 /**
1714  * inc_nlink - directly increment an inode's link count
1715  * @inode: inode
1716  *
1717  * This is a low-level filesystem helper to replace any
1718  * direct filesystem manipulation of i_nlink.  Currently,
1719  * it is only here for parity with dec_nlink().
1720  */
1721 static inline void inc_nlink(struct inode *inode)
1722 {
1723 	inode->i_nlink++;
1724 }
1725 
1726 static inline void inode_inc_link_count(struct inode *inode)
1727 {
1728 	inc_nlink(inode);
1729 	mark_inode_dirty(inode);
1730 }
1731 
1732 /**
1733  * drop_nlink - directly drop an inode's link count
1734  * @inode: inode
1735  *
1736  * This is a low-level filesystem helper to replace any
1737  * direct filesystem manipulation of i_nlink.  In cases
1738  * where we are attempting to track writes to the
1739  * filesystem, a decrement to zero means an imminent
1740  * write when the file is truncated and actually unlinked
1741  * on the filesystem.
1742  */
1743 static inline void drop_nlink(struct inode *inode)
1744 {
1745 	inode->i_nlink--;
1746 }
1747 
1748 /**
1749  * clear_nlink - directly zero an inode's link count
1750  * @inode: inode
1751  *
1752  * This is a low-level filesystem helper to replace any
1753  * direct filesystem manipulation of i_nlink.  See
1754  * drop_nlink() for why we care about i_nlink hitting zero.
1755  */
1756 static inline void clear_nlink(struct inode *inode)
1757 {
1758 	inode->i_nlink = 0;
1759 }
1760 
1761 static inline void inode_dec_link_count(struct inode *inode)
1762 {
1763 	drop_nlink(inode);
1764 	mark_inode_dirty(inode);
1765 }
1766 
1767 /**
1768  * inode_inc_iversion - increments i_version
1769  * @inode: inode that need to be updated
1770  *
1771  * Every time the inode is modified, the i_version field will be incremented.
1772  * The filesystem has to be mounted with i_version flag
1773  */
1774 
1775 static inline void inode_inc_iversion(struct inode *inode)
1776 {
1777        spin_lock(&inode->i_lock);
1778        inode->i_version++;
1779        spin_unlock(&inode->i_lock);
1780 }
1781 
1782 extern void touch_atime(struct vfsmount *mnt, struct dentry *dentry);
1783 static inline void file_accessed(struct file *file)
1784 {
1785 	if (!(file->f_flags & O_NOATIME))
1786 		touch_atime(file->f_path.mnt, file->f_path.dentry);
1787 }
1788 
1789 int sync_inode(struct inode *inode, struct writeback_control *wbc);
1790 int sync_inode_metadata(struct inode *inode, int wait);
1791 
1792 struct file_system_type {
1793 	const char *name;
1794 	int fs_flags;
1795 	struct dentry *(*mount) (struct file_system_type *, int,
1796 		       const char *, void *);
1797 	void (*kill_sb) (struct super_block *);
1798 	struct module *owner;
1799 	struct file_system_type * next;
1800 	struct list_head fs_supers;
1801 
1802 	struct lock_class_key s_lock_key;
1803 	struct lock_class_key s_umount_key;
1804 	struct lock_class_key s_vfs_rename_key;
1805 
1806 	struct lock_class_key i_lock_key;
1807 	struct lock_class_key i_mutex_key;
1808 	struct lock_class_key i_mutex_dir_key;
1809 	struct lock_class_key i_alloc_sem_key;
1810 };
1811 
1812 extern struct dentry *mount_ns(struct file_system_type *fs_type, int flags,
1813 	void *data, int (*fill_super)(struct super_block *, void *, int));
1814 extern struct dentry *mount_bdev(struct file_system_type *fs_type,
1815 	int flags, const char *dev_name, void *data,
1816 	int (*fill_super)(struct super_block *, void *, int));
1817 extern struct dentry *mount_single(struct file_system_type *fs_type,
1818 	int flags, void *data,
1819 	int (*fill_super)(struct super_block *, void *, int));
1820 extern struct dentry *mount_nodev(struct file_system_type *fs_type,
1821 	int flags, void *data,
1822 	int (*fill_super)(struct super_block *, void *, int));
1823 void generic_shutdown_super(struct super_block *sb);
1824 void kill_block_super(struct super_block *sb);
1825 void kill_anon_super(struct super_block *sb);
1826 void kill_litter_super(struct super_block *sb);
1827 void deactivate_super(struct super_block *sb);
1828 void deactivate_locked_super(struct super_block *sb);
1829 int set_anon_super(struct super_block *s, void *data);
1830 struct super_block *sget(struct file_system_type *type,
1831 			int (*test)(struct super_block *,void *),
1832 			int (*set)(struct super_block *,void *),
1833 			void *data);
1834 extern struct dentry *mount_pseudo(struct file_system_type *, char *,
1835 	const struct super_operations *ops,
1836 	const struct dentry_operations *dops,
1837 	unsigned long);
1838 
1839 static inline void sb_mark_dirty(struct super_block *sb)
1840 {
1841 	sb->s_dirt = 1;
1842 }
1843 static inline void sb_mark_clean(struct super_block *sb)
1844 {
1845 	sb->s_dirt = 0;
1846 }
1847 static inline int sb_is_dirty(struct super_block *sb)
1848 {
1849 	return sb->s_dirt;
1850 }
1851 
1852 /* Alas, no aliases. Too much hassle with bringing module.h everywhere */
1853 #define fops_get(fops) \
1854 	(((fops) && try_module_get((fops)->owner) ? (fops) : NULL))
1855 #define fops_put(fops) \
1856 	do { if (fops) module_put((fops)->owner); } while(0)
1857 
1858 extern int register_filesystem(struct file_system_type *);
1859 extern int unregister_filesystem(struct file_system_type *);
1860 extern struct vfsmount *kern_mount_data(struct file_system_type *, void *data);
1861 #define kern_mount(type) kern_mount_data(type, NULL)
1862 extern int may_umount_tree(struct vfsmount *);
1863 extern int may_umount(struct vfsmount *);
1864 extern long do_mount(char *, char *, char *, unsigned long, void *);
1865 extern struct vfsmount *collect_mounts(struct path *);
1866 extern void drop_collected_mounts(struct vfsmount *);
1867 extern int iterate_mounts(int (*)(struct vfsmount *, void *), void *,
1868 			  struct vfsmount *);
1869 extern int vfs_statfs(struct path *, struct kstatfs *);
1870 extern int user_statfs(const char __user *, struct kstatfs *);
1871 extern int fd_statfs(int, struct kstatfs *);
1872 extern int statfs_by_dentry(struct dentry *, struct kstatfs *);
1873 extern int freeze_super(struct super_block *super);
1874 extern int thaw_super(struct super_block *super);
1875 
1876 extern int current_umask(void);
1877 
1878 /* /sys/fs */
1879 extern struct kobject *fs_kobj;
1880 
1881 #define MAX_RW_COUNT (INT_MAX & PAGE_CACHE_MASK)
1882 extern int rw_verify_area(int, struct file *, loff_t *, size_t);
1883 
1884 #define FLOCK_VERIFY_READ  1
1885 #define FLOCK_VERIFY_WRITE 2
1886 
1887 #ifdef CONFIG_FILE_LOCKING
1888 extern int locks_mandatory_locked(struct inode *);
1889 extern int locks_mandatory_area(int, struct inode *, struct file *, loff_t, size_t);
1890 
1891 /*
1892  * Candidates for mandatory locking have the setgid bit set
1893  * but no group execute bit -  an otherwise meaningless combination.
1894  */
1895 
1896 static inline int __mandatory_lock(struct inode *ino)
1897 {
1898 	return (ino->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID;
1899 }
1900 
1901 /*
1902  * ... and these candidates should be on MS_MANDLOCK mounted fs,
1903  * otherwise these will be advisory locks
1904  */
1905 
1906 static inline int mandatory_lock(struct inode *ino)
1907 {
1908 	return IS_MANDLOCK(ino) && __mandatory_lock(ino);
1909 }
1910 
1911 static inline int locks_verify_locked(struct inode *inode)
1912 {
1913 	if (mandatory_lock(inode))
1914 		return locks_mandatory_locked(inode);
1915 	return 0;
1916 }
1917 
1918 static inline int locks_verify_truncate(struct inode *inode,
1919 				    struct file *filp,
1920 				    loff_t size)
1921 {
1922 	if (inode->i_flock && mandatory_lock(inode))
1923 		return locks_mandatory_area(
1924 			FLOCK_VERIFY_WRITE, inode, filp,
1925 			size < inode->i_size ? size : inode->i_size,
1926 			(size < inode->i_size ? inode->i_size - size
1927 			 : size - inode->i_size)
1928 		);
1929 	return 0;
1930 }
1931 
1932 static inline int break_lease(struct inode *inode, unsigned int mode)
1933 {
1934 	if (inode->i_flock)
1935 		return __break_lease(inode, mode);
1936 	return 0;
1937 }
1938 #else /* !CONFIG_FILE_LOCKING */
1939 static inline int locks_mandatory_locked(struct inode *inode)
1940 {
1941 	return 0;
1942 }
1943 
1944 static inline int locks_mandatory_area(int rw, struct inode *inode,
1945 				       struct file *filp, loff_t offset,
1946 				       size_t count)
1947 {
1948 	return 0;
1949 }
1950 
1951 static inline int __mandatory_lock(struct inode *inode)
1952 {
1953 	return 0;
1954 }
1955 
1956 static inline int mandatory_lock(struct inode *inode)
1957 {
1958 	return 0;
1959 }
1960 
1961 static inline int locks_verify_locked(struct inode *inode)
1962 {
1963 	return 0;
1964 }
1965 
1966 static inline int locks_verify_truncate(struct inode *inode, struct file *filp,
1967 					size_t size)
1968 {
1969 	return 0;
1970 }
1971 
1972 static inline int break_lease(struct inode *inode, unsigned int mode)
1973 {
1974 	return 0;
1975 }
1976 
1977 #endif /* CONFIG_FILE_LOCKING */
1978 
1979 /* fs/open.c */
1980 
1981 extern int do_truncate(struct dentry *, loff_t start, unsigned int time_attrs,
1982 		       struct file *filp);
1983 extern int do_fallocate(struct file *file, int mode, loff_t offset,
1984 			loff_t len);
1985 extern long do_sys_open(int dfd, const char __user *filename, int flags,
1986 			int mode);
1987 extern struct file *filp_open(const char *, int, int);
1988 extern struct file *file_open_root(struct dentry *, struct vfsmount *,
1989 				   const char *, int);
1990 extern struct file * dentry_open(struct dentry *, struct vfsmount *, int,
1991 				 const struct cred *);
1992 extern int filp_close(struct file *, fl_owner_t id);
1993 extern char * getname(const char __user *);
1994 
1995 /* fs/ioctl.c */
1996 
1997 extern int ioctl_preallocate(struct file *filp, void __user *argp);
1998 
1999 /* fs/dcache.c */
2000 extern void __init vfs_caches_init_early(void);
2001 extern void __init vfs_caches_init(unsigned long);
2002 
2003 extern struct kmem_cache *names_cachep;
2004 
2005 #define __getname_gfp(gfp)	kmem_cache_alloc(names_cachep, (gfp))
2006 #define __getname()		__getname_gfp(GFP_KERNEL)
2007 #define __putname(name)		kmem_cache_free(names_cachep, (void *)(name))
2008 #ifndef CONFIG_AUDITSYSCALL
2009 #define putname(name)   __putname(name)
2010 #else
2011 extern void putname(const char *name);
2012 #endif
2013 
2014 #ifdef CONFIG_BLOCK
2015 extern int register_blkdev(unsigned int, const char *);
2016 extern void unregister_blkdev(unsigned int, const char *);
2017 extern struct block_device *bdget(dev_t);
2018 extern struct block_device *bdgrab(struct block_device *bdev);
2019 extern void bd_set_size(struct block_device *, loff_t size);
2020 extern void bd_forget(struct inode *inode);
2021 extern void bdput(struct block_device *);
2022 extern void invalidate_bdev(struct block_device *);
2023 extern int sync_blockdev(struct block_device *bdev);
2024 extern struct super_block *freeze_bdev(struct block_device *);
2025 extern void emergency_thaw_all(void);
2026 extern int thaw_bdev(struct block_device *bdev, struct super_block *sb);
2027 extern int fsync_bdev(struct block_device *);
2028 #else
2029 static inline void bd_forget(struct inode *inode) {}
2030 static inline int sync_blockdev(struct block_device *bdev) { return 0; }
2031 static inline void invalidate_bdev(struct block_device *bdev) {}
2032 
2033 static inline struct super_block *freeze_bdev(struct block_device *sb)
2034 {
2035 	return NULL;
2036 }
2037 
2038 static inline int thaw_bdev(struct block_device *bdev, struct super_block *sb)
2039 {
2040 	return 0;
2041 }
2042 #endif
2043 extern int sync_filesystem(struct super_block *);
2044 extern const struct file_operations def_blk_fops;
2045 extern const struct file_operations def_chr_fops;
2046 extern const struct file_operations bad_sock_fops;
2047 extern const struct file_operations def_fifo_fops;
2048 #ifdef CONFIG_BLOCK
2049 extern int ioctl_by_bdev(struct block_device *, unsigned, unsigned long);
2050 extern int blkdev_ioctl(struct block_device *, fmode_t, unsigned, unsigned long);
2051 extern long compat_blkdev_ioctl(struct file *, unsigned, unsigned long);
2052 extern int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder);
2053 extern struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
2054 					       void *holder);
2055 extern struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode,
2056 					      void *holder);
2057 extern int blkdev_put(struct block_device *bdev, fmode_t mode);
2058 #ifdef CONFIG_SYSFS
2059 extern int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk);
2060 extern void bd_unlink_disk_holder(struct block_device *bdev,
2061 				  struct gendisk *disk);
2062 #else
2063 static inline int bd_link_disk_holder(struct block_device *bdev,
2064 				      struct gendisk *disk)
2065 {
2066 	return 0;
2067 }
2068 static inline void bd_unlink_disk_holder(struct block_device *bdev,
2069 					 struct gendisk *disk)
2070 {
2071 }
2072 #endif
2073 #endif
2074 
2075 /* fs/char_dev.c */
2076 #define CHRDEV_MAJOR_HASH_SIZE	255
2077 extern int alloc_chrdev_region(dev_t *, unsigned, unsigned, const char *);
2078 extern int register_chrdev_region(dev_t, unsigned, const char *);
2079 extern int __register_chrdev(unsigned int major, unsigned int baseminor,
2080 			     unsigned int count, const char *name,
2081 			     const struct file_operations *fops);
2082 extern void __unregister_chrdev(unsigned int major, unsigned int baseminor,
2083 				unsigned int count, const char *name);
2084 extern void unregister_chrdev_region(dev_t, unsigned);
2085 extern void chrdev_show(struct seq_file *,off_t);
2086 
2087 static inline int register_chrdev(unsigned int major, const char *name,
2088 				  const struct file_operations *fops)
2089 {
2090 	return __register_chrdev(major, 0, 256, name, fops);
2091 }
2092 
2093 static inline void unregister_chrdev(unsigned int major, const char *name)
2094 {
2095 	__unregister_chrdev(major, 0, 256, name);
2096 }
2097 
2098 /* fs/block_dev.c */
2099 #define BDEVNAME_SIZE	32	/* Largest string for a blockdev identifier */
2100 #define BDEVT_SIZE	10	/* Largest string for MAJ:MIN for blkdev */
2101 
2102 #ifdef CONFIG_BLOCK
2103 #define BLKDEV_MAJOR_HASH_SIZE	255
2104 extern const char *__bdevname(dev_t, char *buffer);
2105 extern const char *bdevname(struct block_device *bdev, char *buffer);
2106 extern struct block_device *lookup_bdev(const char *);
2107 extern void blkdev_show(struct seq_file *,off_t);
2108 
2109 #else
2110 #define BLKDEV_MAJOR_HASH_SIZE	0
2111 #endif
2112 
2113 extern void init_special_inode(struct inode *, umode_t, dev_t);
2114 
2115 /* Invalid inode operations -- fs/bad_inode.c */
2116 extern void make_bad_inode(struct inode *);
2117 extern int is_bad_inode(struct inode *);
2118 
2119 extern const struct file_operations read_pipefifo_fops;
2120 extern const struct file_operations write_pipefifo_fops;
2121 extern const struct file_operations rdwr_pipefifo_fops;
2122 
2123 extern int fs_may_remount_ro(struct super_block *);
2124 
2125 #ifdef CONFIG_BLOCK
2126 /*
2127  * return READ, READA, or WRITE
2128  */
2129 #define bio_rw(bio)		((bio)->bi_rw & (RW_MASK | RWA_MASK))
2130 
2131 /*
2132  * return data direction, READ or WRITE
2133  */
2134 #define bio_data_dir(bio)	((bio)->bi_rw & 1)
2135 
2136 extern void check_disk_size_change(struct gendisk *disk,
2137 				   struct block_device *bdev);
2138 extern int revalidate_disk(struct gendisk *);
2139 extern int check_disk_change(struct block_device *);
2140 extern int __invalidate_device(struct block_device *, bool);
2141 extern int invalidate_partition(struct gendisk *, int);
2142 #endif
2143 unsigned long invalidate_mapping_pages(struct address_space *mapping,
2144 					pgoff_t start, pgoff_t end);
2145 
2146 static inline void invalidate_remote_inode(struct inode *inode)
2147 {
2148 	if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
2149 	    S_ISLNK(inode->i_mode))
2150 		invalidate_mapping_pages(inode->i_mapping, 0, -1);
2151 }
2152 extern int invalidate_inode_pages2(struct address_space *mapping);
2153 extern int invalidate_inode_pages2_range(struct address_space *mapping,
2154 					 pgoff_t start, pgoff_t end);
2155 extern int write_inode_now(struct inode *, int);
2156 extern int filemap_fdatawrite(struct address_space *);
2157 extern int filemap_flush(struct address_space *);
2158 extern int filemap_fdatawait(struct address_space *);
2159 extern int filemap_fdatawait_range(struct address_space *, loff_t lstart,
2160 				   loff_t lend);
2161 extern int filemap_write_and_wait(struct address_space *mapping);
2162 extern int filemap_write_and_wait_range(struct address_space *mapping,
2163 				        loff_t lstart, loff_t lend);
2164 extern int __filemap_fdatawrite_range(struct address_space *mapping,
2165 				loff_t start, loff_t end, int sync_mode);
2166 extern int filemap_fdatawrite_range(struct address_space *mapping,
2167 				loff_t start, loff_t end);
2168 
2169 extern int vfs_fsync_range(struct file *file, loff_t start, loff_t end,
2170 			   int datasync);
2171 extern int vfs_fsync(struct file *file, int datasync);
2172 extern int generic_write_sync(struct file *file, loff_t pos, loff_t count);
2173 extern void sync_supers(void);
2174 extern void emergency_sync(void);
2175 extern void emergency_remount(void);
2176 #ifdef CONFIG_BLOCK
2177 extern sector_t bmap(struct inode *, sector_t);
2178 #endif
2179 extern int notify_change(struct dentry *, struct iattr *);
2180 extern int inode_permission(struct inode *, int);
2181 extern int generic_permission(struct inode *, int, unsigned int,
2182 		int (*check_acl)(struct inode *, int, unsigned int));
2183 
2184 static inline bool execute_ok(struct inode *inode)
2185 {
2186 	return (inode->i_mode & S_IXUGO) || S_ISDIR(inode->i_mode);
2187 }
2188 
2189 extern int get_write_access(struct inode *);
2190 extern int deny_write_access(struct file *);
2191 static inline void put_write_access(struct inode * inode)
2192 {
2193 	atomic_dec(&inode->i_writecount);
2194 }
2195 static inline void allow_write_access(struct file *file)
2196 {
2197 	if (file)
2198 		atomic_inc(&file->f_path.dentry->d_inode->i_writecount);
2199 }
2200 #ifdef CONFIG_IMA
2201 static inline void i_readcount_dec(struct inode *inode)
2202 {
2203 	BUG_ON(!atomic_read(&inode->i_readcount));
2204 	atomic_dec(&inode->i_readcount);
2205 }
2206 static inline void i_readcount_inc(struct inode *inode)
2207 {
2208 	atomic_inc(&inode->i_readcount);
2209 }
2210 #else
2211 static inline void i_readcount_dec(struct inode *inode)
2212 {
2213 	return;
2214 }
2215 static inline void i_readcount_inc(struct inode *inode)
2216 {
2217 	return;
2218 }
2219 #endif
2220 extern int do_pipe_flags(int *, int);
2221 extern struct file *create_read_pipe(struct file *f, int flags);
2222 extern struct file *create_write_pipe(int flags);
2223 extern void free_write_pipe(struct file *);
2224 
2225 extern int kernel_read(struct file *, loff_t, char *, unsigned long);
2226 extern struct file * open_exec(const char *);
2227 
2228 /* fs/dcache.c -- generic fs support functions */
2229 extern int is_subdir(struct dentry *, struct dentry *);
2230 extern int path_is_under(struct path *, struct path *);
2231 extern ino_t find_inode_number(struct dentry *, struct qstr *);
2232 
2233 #include <linux/err.h>
2234 
2235 /* needed for stackable file system support */
2236 extern loff_t default_llseek(struct file *file, loff_t offset, int origin);
2237 
2238 extern loff_t vfs_llseek(struct file *file, loff_t offset, int origin);
2239 
2240 extern int inode_init_always(struct super_block *, struct inode *);
2241 extern void inode_init_once(struct inode *);
2242 extern void address_space_init_once(struct address_space *mapping);
2243 extern void ihold(struct inode * inode);
2244 extern void iput(struct inode *);
2245 extern struct inode * igrab(struct inode *);
2246 extern ino_t iunique(struct super_block *, ino_t);
2247 extern int inode_needs_sync(struct inode *inode);
2248 extern int generic_delete_inode(struct inode *inode);
2249 extern int generic_drop_inode(struct inode *inode);
2250 
2251 extern struct inode *ilookup5_nowait(struct super_block *sb,
2252 		unsigned long hashval, int (*test)(struct inode *, void *),
2253 		void *data);
2254 extern struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
2255 		int (*test)(struct inode *, void *), void *data);
2256 extern struct inode *ilookup(struct super_block *sb, unsigned long ino);
2257 
2258 extern struct inode * iget5_locked(struct super_block *, unsigned long, int (*test)(struct inode *, void *), int (*set)(struct inode *, void *), void *);
2259 extern struct inode * iget_locked(struct super_block *, unsigned long);
2260 extern int insert_inode_locked4(struct inode *, unsigned long, int (*test)(struct inode *, void *), void *);
2261 extern int insert_inode_locked(struct inode *);
2262 extern void unlock_new_inode(struct inode *);
2263 extern unsigned int get_next_ino(void);
2264 
2265 extern void __iget(struct inode * inode);
2266 extern void iget_failed(struct inode *);
2267 extern void end_writeback(struct inode *);
2268 extern void __destroy_inode(struct inode *);
2269 extern struct inode *new_inode(struct super_block *);
2270 extern void free_inode_nonrcu(struct inode *inode);
2271 extern int should_remove_suid(struct dentry *);
2272 extern int file_remove_suid(struct file *);
2273 
2274 extern void __insert_inode_hash(struct inode *, unsigned long hashval);
2275 extern void remove_inode_hash(struct inode *);
2276 static inline void insert_inode_hash(struct inode *inode)
2277 {
2278 	__insert_inode_hash(inode, inode->i_ino);
2279 }
2280 extern void inode_sb_list_add(struct inode *inode);
2281 
2282 #ifdef CONFIG_BLOCK
2283 extern void submit_bio(int, struct bio *);
2284 extern int bdev_read_only(struct block_device *);
2285 #endif
2286 extern int set_blocksize(struct block_device *, int);
2287 extern int sb_set_blocksize(struct super_block *, int);
2288 extern int sb_min_blocksize(struct super_block *, int);
2289 
2290 extern int generic_file_mmap(struct file *, struct vm_area_struct *);
2291 extern int generic_file_readonly_mmap(struct file *, struct vm_area_struct *);
2292 extern int file_read_actor(read_descriptor_t * desc, struct page *page, unsigned long offset, unsigned long size);
2293 int generic_write_checks(struct file *file, loff_t *pos, size_t *count, int isblk);
2294 extern ssize_t generic_file_aio_read(struct kiocb *, const struct iovec *, unsigned long, loff_t);
2295 extern ssize_t __generic_file_aio_write(struct kiocb *, const struct iovec *, unsigned long,
2296 		loff_t *);
2297 extern ssize_t generic_file_aio_write(struct kiocb *, const struct iovec *, unsigned long, loff_t);
2298 extern ssize_t generic_file_direct_write(struct kiocb *, const struct iovec *,
2299 		unsigned long *, loff_t, loff_t *, size_t, size_t);
2300 extern ssize_t generic_file_buffered_write(struct kiocb *, const struct iovec *,
2301 		unsigned long, loff_t, loff_t *, size_t, ssize_t);
2302 extern ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos);
2303 extern ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos);
2304 extern int generic_segment_checks(const struct iovec *iov,
2305 		unsigned long *nr_segs, size_t *count, int access_flags);
2306 
2307 /* fs/block_dev.c */
2308 extern ssize_t blkdev_aio_write(struct kiocb *iocb, const struct iovec *iov,
2309 				unsigned long nr_segs, loff_t pos);
2310 extern int blkdev_fsync(struct file *filp, int datasync);
2311 
2312 /* fs/splice.c */
2313 extern ssize_t generic_file_splice_read(struct file *, loff_t *,
2314 		struct pipe_inode_info *, size_t, unsigned int);
2315 extern ssize_t default_file_splice_read(struct file *, loff_t *,
2316 		struct pipe_inode_info *, size_t, unsigned int);
2317 extern ssize_t generic_file_splice_write(struct pipe_inode_info *,
2318 		struct file *, loff_t *, size_t, unsigned int);
2319 extern ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe,
2320 		struct file *out, loff_t *, size_t len, unsigned int flags);
2321 extern long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
2322 		size_t len, unsigned int flags);
2323 
2324 extern void
2325 file_ra_state_init(struct file_ra_state *ra, struct address_space *mapping);
2326 extern loff_t noop_llseek(struct file *file, loff_t offset, int origin);
2327 extern loff_t no_llseek(struct file *file, loff_t offset, int origin);
2328 extern loff_t generic_file_llseek(struct file *file, loff_t offset, int origin);
2329 extern loff_t generic_file_llseek_unlocked(struct file *file, loff_t offset,
2330 			int origin);
2331 extern int generic_file_open(struct inode * inode, struct file * filp);
2332 extern int nonseekable_open(struct inode * inode, struct file * filp);
2333 
2334 #ifdef CONFIG_FS_XIP
2335 extern ssize_t xip_file_read(struct file *filp, char __user *buf, size_t len,
2336 			     loff_t *ppos);
2337 extern int xip_file_mmap(struct file * file, struct vm_area_struct * vma);
2338 extern ssize_t xip_file_write(struct file *filp, const char __user *buf,
2339 			      size_t len, loff_t *ppos);
2340 extern int xip_truncate_page(struct address_space *mapping, loff_t from);
2341 #else
2342 static inline int xip_truncate_page(struct address_space *mapping, loff_t from)
2343 {
2344 	return 0;
2345 }
2346 #endif
2347 
2348 #ifdef CONFIG_BLOCK
2349 typedef void (dio_submit_t)(int rw, struct bio *bio, struct inode *inode,
2350 			    loff_t file_offset);
2351 
2352 enum {
2353 	/* need locking between buffered and direct access */
2354 	DIO_LOCKING	= 0x01,
2355 
2356 	/* filesystem does not support filling holes */
2357 	DIO_SKIP_HOLES	= 0x02,
2358 };
2359 
2360 void dio_end_io(struct bio *bio, int error);
2361 
2362 ssize_t __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
2363 	struct block_device *bdev, const struct iovec *iov, loff_t offset,
2364 	unsigned long nr_segs, get_block_t get_block, dio_iodone_t end_io,
2365 	dio_submit_t submit_io,	int flags);
2366 
2367 static inline ssize_t blockdev_direct_IO(int rw, struct kiocb *iocb,
2368 	struct inode *inode, struct block_device *bdev, const struct iovec *iov,
2369 	loff_t offset, unsigned long nr_segs, get_block_t get_block,
2370 	dio_iodone_t end_io)
2371 {
2372 	return __blockdev_direct_IO(rw, iocb, inode, bdev, iov, offset,
2373 				    nr_segs, get_block, end_io, NULL,
2374 				    DIO_LOCKING | DIO_SKIP_HOLES);
2375 }
2376 #endif
2377 
2378 extern const struct file_operations generic_ro_fops;
2379 
2380 #define special_file(m) (S_ISCHR(m)||S_ISBLK(m)||S_ISFIFO(m)||S_ISSOCK(m))
2381 
2382 extern int vfs_readlink(struct dentry *, char __user *, int, const char *);
2383 extern int vfs_follow_link(struct nameidata *, const char *);
2384 extern int page_readlink(struct dentry *, char __user *, int);
2385 extern void *page_follow_link_light(struct dentry *, struct nameidata *);
2386 extern void page_put_link(struct dentry *, struct nameidata *, void *);
2387 extern int __page_symlink(struct inode *inode, const char *symname, int len,
2388 		int nofs);
2389 extern int page_symlink(struct inode *inode, const char *symname, int len);
2390 extern const struct inode_operations page_symlink_inode_operations;
2391 extern int generic_readlink(struct dentry *, char __user *, int);
2392 extern void generic_fillattr(struct inode *, struct kstat *);
2393 extern int vfs_getattr(struct vfsmount *, struct dentry *, struct kstat *);
2394 void __inode_add_bytes(struct inode *inode, loff_t bytes);
2395 void inode_add_bytes(struct inode *inode, loff_t bytes);
2396 void inode_sub_bytes(struct inode *inode, loff_t bytes);
2397 loff_t inode_get_bytes(struct inode *inode);
2398 void inode_set_bytes(struct inode *inode, loff_t bytes);
2399 
2400 extern int vfs_readdir(struct file *, filldir_t, void *);
2401 
2402 extern int vfs_stat(const char __user *, struct kstat *);
2403 extern int vfs_lstat(const char __user *, struct kstat *);
2404 extern int vfs_fstat(unsigned int, struct kstat *);
2405 extern int vfs_fstatat(int , const char __user *, struct kstat *, int);
2406 
2407 extern int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd,
2408 		    unsigned long arg);
2409 extern int __generic_block_fiemap(struct inode *inode,
2410 				  struct fiemap_extent_info *fieinfo,
2411 				  loff_t start, loff_t len,
2412 				  get_block_t *get_block);
2413 extern int generic_block_fiemap(struct inode *inode,
2414 				struct fiemap_extent_info *fieinfo, u64 start,
2415 				u64 len, get_block_t *get_block);
2416 
2417 extern void get_filesystem(struct file_system_type *fs);
2418 extern void put_filesystem(struct file_system_type *fs);
2419 extern struct file_system_type *get_fs_type(const char *name);
2420 extern struct super_block *get_super(struct block_device *);
2421 extern struct super_block *get_active_super(struct block_device *bdev);
2422 extern struct super_block *user_get_super(dev_t);
2423 extern void drop_super(struct super_block *sb);
2424 extern void iterate_supers(void (*)(struct super_block *, void *), void *);
2425 
2426 extern int dcache_dir_open(struct inode *, struct file *);
2427 extern int dcache_dir_close(struct inode *, struct file *);
2428 extern loff_t dcache_dir_lseek(struct file *, loff_t, int);
2429 extern int dcache_readdir(struct file *, void *, filldir_t);
2430 extern int simple_setattr(struct dentry *, struct iattr *);
2431 extern int simple_getattr(struct vfsmount *, struct dentry *, struct kstat *);
2432 extern int simple_statfs(struct dentry *, struct kstatfs *);
2433 extern int simple_link(struct dentry *, struct inode *, struct dentry *);
2434 extern int simple_unlink(struct inode *, struct dentry *);
2435 extern int simple_rmdir(struct inode *, struct dentry *);
2436 extern int simple_rename(struct inode *, struct dentry *, struct inode *, struct dentry *);
2437 extern int noop_fsync(struct file *, int);
2438 extern int simple_empty(struct dentry *);
2439 extern int simple_readpage(struct file *file, struct page *page);
2440 extern int simple_write_begin(struct file *file, struct address_space *mapping,
2441 			loff_t pos, unsigned len, unsigned flags,
2442 			struct page **pagep, void **fsdata);
2443 extern int simple_write_end(struct file *file, struct address_space *mapping,
2444 			loff_t pos, unsigned len, unsigned copied,
2445 			struct page *page, void *fsdata);
2446 
2447 extern struct dentry *simple_lookup(struct inode *, struct dentry *, struct nameidata *);
2448 extern ssize_t generic_read_dir(struct file *, char __user *, size_t, loff_t *);
2449 extern const struct file_operations simple_dir_operations;
2450 extern const struct inode_operations simple_dir_inode_operations;
2451 struct tree_descr { char *name; const struct file_operations *ops; int mode; };
2452 struct dentry *d_alloc_name(struct dentry *, const char *);
2453 extern int simple_fill_super(struct super_block *, unsigned long, struct tree_descr *);
2454 extern int simple_pin_fs(struct file_system_type *, struct vfsmount **mount, int *count);
2455 extern void simple_release_fs(struct vfsmount **mount, int *count);
2456 
2457 extern ssize_t simple_read_from_buffer(void __user *to, size_t count,
2458 			loff_t *ppos, const void *from, size_t available);
2459 extern ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos,
2460 		const void __user *from, size_t count);
2461 
2462 extern int generic_file_fsync(struct file *, int);
2463 
2464 extern int generic_check_addressable(unsigned, u64);
2465 
2466 #ifdef CONFIG_MIGRATION
2467 extern int buffer_migrate_page(struct address_space *,
2468 				struct page *, struct page *);
2469 #else
2470 #define buffer_migrate_page NULL
2471 #endif
2472 
2473 extern int inode_change_ok(const struct inode *, struct iattr *);
2474 extern int inode_newsize_ok(const struct inode *, loff_t offset);
2475 extern void setattr_copy(struct inode *inode, const struct iattr *attr);
2476 
2477 extern void file_update_time(struct file *file);
2478 
2479 extern int generic_show_options(struct seq_file *m, struct vfsmount *mnt);
2480 extern void save_mount_options(struct super_block *sb, char *options);
2481 extern void replace_mount_options(struct super_block *sb, char *options);
2482 
2483 static inline ino_t parent_ino(struct dentry *dentry)
2484 {
2485 	ino_t res;
2486 
2487 	/*
2488 	 * Don't strictly need d_lock here? If the parent ino could change
2489 	 * then surely we'd have a deeper race in the caller?
2490 	 */
2491 	spin_lock(&dentry->d_lock);
2492 	res = dentry->d_parent->d_inode->i_ino;
2493 	spin_unlock(&dentry->d_lock);
2494 	return res;
2495 }
2496 
2497 /* Transaction based IO helpers */
2498 
2499 /*
2500  * An argresp is stored in an allocated page and holds the
2501  * size of the argument or response, along with its content
2502  */
2503 struct simple_transaction_argresp {
2504 	ssize_t size;
2505 	char data[0];
2506 };
2507 
2508 #define SIMPLE_TRANSACTION_LIMIT (PAGE_SIZE - sizeof(struct simple_transaction_argresp))
2509 
2510 char *simple_transaction_get(struct file *file, const char __user *buf,
2511 				size_t size);
2512 ssize_t simple_transaction_read(struct file *file, char __user *buf,
2513 				size_t size, loff_t *pos);
2514 int simple_transaction_release(struct inode *inode, struct file *file);
2515 
2516 void simple_transaction_set(struct file *file, size_t n);
2517 
2518 /*
2519  * simple attribute files
2520  *
2521  * These attributes behave similar to those in sysfs:
2522  *
2523  * Writing to an attribute immediately sets a value, an open file can be
2524  * written to multiple times.
2525  *
2526  * Reading from an attribute creates a buffer from the value that might get
2527  * read with multiple read calls. When the attribute has been read
2528  * completely, no further read calls are possible until the file is opened
2529  * again.
2530  *
2531  * All attributes contain a text representation of a numeric value
2532  * that are accessed with the get() and set() functions.
2533  */
2534 #define DEFINE_SIMPLE_ATTRIBUTE(__fops, __get, __set, __fmt)		\
2535 static int __fops ## _open(struct inode *inode, struct file *file)	\
2536 {									\
2537 	__simple_attr_check_format(__fmt, 0ull);			\
2538 	return simple_attr_open(inode, file, __get, __set, __fmt);	\
2539 }									\
2540 static const struct file_operations __fops = {				\
2541 	.owner	 = THIS_MODULE,						\
2542 	.open	 = __fops ## _open,					\
2543 	.release = simple_attr_release,					\
2544 	.read	 = simple_attr_read,					\
2545 	.write	 = simple_attr_write,					\
2546 	.llseek	 = generic_file_llseek,					\
2547 };
2548 
2549 static inline void __attribute__((format(printf, 1, 2)))
2550 __simple_attr_check_format(const char *fmt, ...)
2551 {
2552 	/* don't do anything, just let the compiler check the arguments; */
2553 }
2554 
2555 int simple_attr_open(struct inode *inode, struct file *file,
2556 		     int (*get)(void *, u64 *), int (*set)(void *, u64),
2557 		     const char *fmt);
2558 int simple_attr_release(struct inode *inode, struct file *file);
2559 ssize_t simple_attr_read(struct file *file, char __user *buf,
2560 			 size_t len, loff_t *ppos);
2561 ssize_t simple_attr_write(struct file *file, const char __user *buf,
2562 			  size_t len, loff_t *ppos);
2563 
2564 struct ctl_table;
2565 int proc_nr_files(struct ctl_table *table, int write,
2566 		  void __user *buffer, size_t *lenp, loff_t *ppos);
2567 int proc_nr_dentry(struct ctl_table *table, int write,
2568 		  void __user *buffer, size_t *lenp, loff_t *ppos);
2569 int proc_nr_inodes(struct ctl_table *table, int write,
2570 		   void __user *buffer, size_t *lenp, loff_t *ppos);
2571 int __init get_filesystem_list(char *buf);
2572 
2573 #define __FMODE_EXEC		((__force int) FMODE_EXEC)
2574 #define __FMODE_NONOTIFY	((__force int) FMODE_NONOTIFY)
2575 
2576 #define ACC_MODE(x) ("\004\002\006\006"[(x)&O_ACCMODE])
2577 #define OPEN_FMODE(flag) ((__force fmode_t)(((flag + 1) & O_ACCMODE) | \
2578 					    (flag & __FMODE_NONOTIFY)))
2579 
2580 #endif /* __KERNEL__ */
2581 #endif /* _LINUX_FS_H */
2582