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TOMOYO Linux Cross Reference
Linux/include/linux/fs.h

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  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_CUR 1024       /* Initial setting for nfile rlimits */
 27 #define INR_OPEN_MAX 4096       /* Hard limit for nfile rlimits */
 28 
 29 #define BLOCK_SIZE_BITS 10
 30 #define BLOCK_SIZE (1<<BLOCK_SIZE_BITS)
 31 
 32 #define SEEK_SET        0       /* seek relative to beginning of file */
 33 #define SEEK_CUR        1       /* seek relative to current file position */
 34 #define SEEK_END        2       /* seek relative to end of file */
 35 #define SEEK_DATA       3       /* seek to the next data */
 36 #define SEEK_HOLE       4       /* seek to the next hole */
 37 #define SEEK_MAX        SEEK_HOLE
 38 
 39 struct fstrim_range {
 40         __u64 start;
 41         __u64 len;
 42         __u64 minlen;
 43 };
 44 
 45 /* And dynamically-tunable limits and defaults: */
 46 struct files_stat_struct {
 47         unsigned long nr_files;         /* read only */
 48         unsigned long nr_free_files;    /* read only */
 49         unsigned long max_files;                /* tunable */
 50 };
 51 
 52 struct inodes_stat_t {
 53         int nr_inodes;
 54         int nr_unused;
 55         int dummy[5];           /* padding for sysctl ABI compatibility */
 56 };
 57 
 58 
 59 #define NR_FILE  8192   /* this can well be larger on a larger system */
 60 
 61 #define MAY_EXEC                0x00000001
 62 #define MAY_WRITE               0x00000002
 63 #define MAY_READ                0x00000004
 64 #define MAY_APPEND              0x00000008
 65 #define MAY_ACCESS              0x00000010
 66 #define MAY_OPEN                0x00000020
 67 #define MAY_CHDIR               0x00000040
 68 /* called from RCU mode, don't block */
 69 #define MAY_NOT_BLOCK           0x00000080
 70 
 71 /*
 72  * flags in file.f_mode.  Note that FMODE_READ and FMODE_WRITE must correspond
 73  * to O_WRONLY and O_RDWR via the strange trick in __dentry_open()
 74  */
 75 
 76 /* file is open for reading */
 77 #define FMODE_READ              ((__force fmode_t)0x1)
 78 /* file is open for writing */
 79 #define FMODE_WRITE             ((__force fmode_t)0x2)
 80 /* file is seekable */
 81 #define FMODE_LSEEK             ((__force fmode_t)0x4)
 82 /* file can be accessed using pread */
 83 #define FMODE_PREAD             ((__force fmode_t)0x8)
 84 /* file can be accessed using pwrite */
 85 #define FMODE_PWRITE            ((__force fmode_t)0x10)
 86 /* File is opened for execution with sys_execve / sys_uselib */
 87 #define FMODE_EXEC              ((__force fmode_t)0x20)
 88 /* File is opened with O_NDELAY (only set for block devices) */
 89 #define FMODE_NDELAY            ((__force fmode_t)0x40)
 90 /* File is opened with O_EXCL (only set for block devices) */
 91 #define FMODE_EXCL              ((__force fmode_t)0x80)
 92 /* File is opened using open(.., 3, ..) and is writeable only for ioctls
 93    (specialy hack for floppy.c) */
 94 #define FMODE_WRITE_IOCTL       ((__force fmode_t)0x100)
 95 /* 32bit hashes as llseek() offset (for directories) */
 96 #define FMODE_32BITHASH         ((__force fmode_t)0x200)
 97 /* 64bit hashes as llseek() offset (for directories) */
 98 #define FMODE_64BITHASH         ((__force fmode_t)0x400)
 99 
100 /*
101  * Don't update ctime and mtime.
102  *
103  * Currently a special hack for the XFS open_by_handle ioctl, but we'll
104  * hopefully graduate it to a proper O_CMTIME flag supported by open(2) soon.
105  */
106 #define FMODE_NOCMTIME          ((__force fmode_t)0x800)
107 
108 /* Expect random access pattern */
109 #define FMODE_RANDOM            ((__force fmode_t)0x1000)
110 
111 /* File is huge (eg. /dev/kmem): treat loff_t as unsigned */
112 #define FMODE_UNSIGNED_OFFSET   ((__force fmode_t)0x2000)
113 
114 /* File is opened with O_PATH; almost nothing can be done with it */
115 #define FMODE_PATH              ((__force fmode_t)0x4000)
116 
117 /* File was opened by fanotify and shouldn't generate fanotify events */
118 #define FMODE_NONOTIFY          ((__force fmode_t)0x1000000)
119 
120 /*
121  * The below are the various read and write types that we support. Some of
122  * them include behavioral modifiers that send information down to the
123  * block layer and IO scheduler. Terminology:
124  *
125  *      The block layer uses device plugging to defer IO a little bit, in
126  *      the hope that we will see more IO very shortly. This increases
127  *      coalescing of adjacent IO and thus reduces the number of IOs we
128  *      have to send to the device. It also allows for better queuing,
129  *      if the IO isn't mergeable. If the caller is going to be waiting
130  *      for the IO, then he must ensure that the device is unplugged so
131  *      that the IO is dispatched to the driver.
132  *
133  *      All IO is handled async in Linux. This is fine for background
134  *      writes, but for reads or writes that someone waits for completion
135  *      on, we want to notify the block layer and IO scheduler so that they
136  *      know about it. That allows them to make better scheduling
137  *      decisions. So when the below references 'sync' and 'async', it
138  *      is referencing this priority hint.
139  *
140  * With that in mind, the available types are:
141  *
142  * READ                 A normal read operation. Device will be plugged.
143  * READ_SYNC            A synchronous read. Device is not plugged, caller can
144  *                      immediately wait on this read without caring about
145  *                      unplugging.
146  * READA                Used for read-ahead operations. Lower priority, and the
147  *                      block layer could (in theory) choose to ignore this
148  *                      request if it runs into resource problems.
149  * WRITE                A normal async write. Device will be plugged.
150  * WRITE_SYNC           Synchronous write. Identical to WRITE, but passes down
151  *                      the hint that someone will be waiting on this IO
152  *                      shortly. The write equivalent of READ_SYNC.
153  * WRITE_ODIRECT        Special case write for O_DIRECT only.
154  * WRITE_FLUSH          Like WRITE_SYNC but with preceding cache flush.
155  * WRITE_FUA            Like WRITE_SYNC but data is guaranteed to be on
156  *                      non-volatile media on completion.
157  * WRITE_FLUSH_FUA      Combination of WRITE_FLUSH and FUA. The IO is preceded
158  *                      by a cache flush and data is guaranteed to be on
159  *                      non-volatile media on completion.
160  *
161  */
162 #define RW_MASK                 REQ_WRITE
163 #define RWA_MASK                REQ_RAHEAD
164 
165 #define READ                    0
166 #define WRITE                   RW_MASK
167 #define READA                   RWA_MASK
168 #define KERNEL_READ             (READ|REQ_KERNEL)
169 #define KERNEL_WRITE            (WRITE|REQ_KERNEL)
170 
171 #define READ_SYNC               (READ | REQ_SYNC)
172 #define WRITE_SYNC              (WRITE | REQ_SYNC | REQ_NOIDLE)
173 #define WRITE_ODIRECT           (WRITE | REQ_SYNC)
174 #define WRITE_FLUSH             (WRITE | REQ_SYNC | REQ_NOIDLE | REQ_FLUSH)
175 #define WRITE_FUA               (WRITE | REQ_SYNC | REQ_NOIDLE | REQ_FUA)
176 #define WRITE_FLUSH_FUA         (WRITE | REQ_SYNC | REQ_NOIDLE | REQ_FLUSH | REQ_FUA)
177 
178 
179 /*
180  * Flag for rw_copy_check_uvector and compat_rw_copy_check_uvector
181  * that indicates that they should check the contents of the iovec are
182  * valid, but not check the memory that the iovec elements
183  * points too.
184  */
185 #define CHECK_IOVEC_ONLY -1
186 
187 #define SEL_IN          1
188 #define SEL_OUT         2
189 #define SEL_EX          4
190 
191 /* public flags for file_system_type */
192 #define FS_REQUIRES_DEV 1 
193 #define FS_BINARY_MOUNTDATA 2
194 #define FS_HAS_SUBTYPE 4
195 #define FS_REVAL_DOT    16384   /* Check the paths ".", ".." for staleness */
196 #define FS_RENAME_DOES_D_MOVE   32768   /* FS will handle d_move()
197                                          * during rename() internally.
198                                          */
199 
200 /*
201  * These are the fs-independent mount-flags: up to 32 flags are supported
202  */
203 #define MS_RDONLY        1      /* Mount read-only */
204 #define MS_NOSUID        2      /* Ignore suid and sgid bits */
205 #define MS_NODEV         4      /* Disallow access to device special files */
206 #define MS_NOEXEC        8      /* Disallow program execution */
207 #define MS_SYNCHRONOUS  16      /* Writes are synced at once */
208 #define MS_REMOUNT      32      /* Alter flags of a mounted FS */
209 #define MS_MANDLOCK     64      /* Allow mandatory locks on an FS */
210 #define MS_DIRSYNC      128     /* Directory modifications are synchronous */
211 #define MS_NOATIME      1024    /* Do not update access times. */
212 #define MS_NODIRATIME   2048    /* Do not update directory access times */
213 #define MS_BIND         4096
214 #define MS_MOVE         8192
215 #define MS_REC          16384
216 #define MS_VERBOSE      32768   /* War is peace. Verbosity is silence.
217                                    MS_VERBOSE is deprecated. */
218 #define MS_SILENT       32768
219 #define MS_POSIXACL     (1<<16) /* VFS does not apply the umask */
220 #define MS_UNBINDABLE   (1<<17) /* change to unbindable */
221 #define MS_PRIVATE      (1<<18) /* change to private */
222 #define MS_SLAVE        (1<<19) /* change to slave */
223 #define MS_SHARED       (1<<20) /* change to shared */
224 #define MS_RELATIME     (1<<21) /* Update atime relative to mtime/ctime. */
225 #define MS_KERNMOUNT    (1<<22) /* this is a kern_mount call */
226 #define MS_I_VERSION    (1<<23) /* Update inode I_version field */
227 #define MS_STRICTATIME  (1<<24) /* Always perform atime updates */
228 #define MS_NOSEC        (1<<28)
229 #define MS_BORN         (1<<29)
230 #define MS_ACTIVE       (1<<30)
231 #define MS_NOUSER       (1<<31)
232 
233 /*
234  * Superblock flags that can be altered by MS_REMOUNT
235  */
236 #define MS_RMT_MASK     (MS_RDONLY|MS_SYNCHRONOUS|MS_MANDLOCK|MS_I_VERSION)
237 
238 /*
239  * Old magic mount flag and mask
240  */
241 #define MS_MGC_VAL 0xC0ED0000
242 #define MS_MGC_MSK 0xffff0000
243 
244 /* Inode flags - they have nothing to superblock flags now */
245 
246 #define S_SYNC          1       /* Writes are synced at once */
247 #define S_NOATIME       2       /* Do not update access times */
248 #define S_APPEND        4       /* Append-only file */
249 #define S_IMMUTABLE     8       /* Immutable file */
250 #define S_DEAD          16      /* removed, but still open directory */
251 #define S_NOQUOTA       32      /* Inode is not counted to quota */
252 #define S_DIRSYNC       64      /* Directory modifications are synchronous */
253 #define S_NOCMTIME      128     /* Do not update file c/mtime */
254 #define S_SWAPFILE      256     /* Do not truncate: swapon got its bmaps */
255 #define S_PRIVATE       512     /* Inode is fs-internal */
256 #define S_IMA           1024    /* Inode has an associated IMA struct */
257 #define S_AUTOMOUNT     2048    /* Automount/referral quasi-directory */
258 #define S_NOSEC         4096    /* no suid or xattr security attributes */
259 
260 /*
261  * Note that nosuid etc flags are inode-specific: setting some file-system
262  * flags just means all the inodes inherit those flags by default. It might be
263  * possible to override it selectively if you really wanted to with some
264  * ioctl() that is not currently implemented.
265  *
266  * Exception: MS_RDONLY is always applied to the entire file system.
267  *
268  * Unfortunately, it is possible to change a filesystems flags with it mounted
269  * with files in use.  This means that all of the inodes will not have their
270  * i_flags updated.  Hence, i_flags no longer inherit the superblock mount
271  * flags, so these have to be checked separately. -- rmk@arm.uk.linux.org
272  */
273 #define __IS_FLG(inode,flg) ((inode)->i_sb->s_flags & (flg))
274 
275 #define IS_RDONLY(inode) ((inode)->i_sb->s_flags & MS_RDONLY)
276 #define IS_SYNC(inode)          (__IS_FLG(inode, MS_SYNCHRONOUS) || \
277                                         ((inode)->i_flags & S_SYNC))
278 #define IS_DIRSYNC(inode)       (__IS_FLG(inode, MS_SYNCHRONOUS|MS_DIRSYNC) || \
279                                         ((inode)->i_flags & (S_SYNC|S_DIRSYNC)))
280 #define IS_MANDLOCK(inode)      __IS_FLG(inode, MS_MANDLOCK)
281 #define IS_NOATIME(inode)   __IS_FLG(inode, MS_RDONLY|MS_NOATIME)
282 #define IS_I_VERSION(inode)   __IS_FLG(inode, MS_I_VERSION)
283 
284 #define IS_NOQUOTA(inode)       ((inode)->i_flags & S_NOQUOTA)
285 #define IS_APPEND(inode)        ((inode)->i_flags & S_APPEND)
286 #define IS_IMMUTABLE(inode)     ((inode)->i_flags & S_IMMUTABLE)
287 #define IS_POSIXACL(inode)      __IS_FLG(inode, MS_POSIXACL)
288 
289 #define IS_DEADDIR(inode)       ((inode)->i_flags & S_DEAD)
290 #define IS_NOCMTIME(inode)      ((inode)->i_flags & S_NOCMTIME)
291 #define IS_SWAPFILE(inode)      ((inode)->i_flags & S_SWAPFILE)
292 #define IS_PRIVATE(inode)       ((inode)->i_flags & S_PRIVATE)
293 #define IS_IMA(inode)           ((inode)->i_flags & S_IMA)
294 #define IS_AUTOMOUNT(inode)     ((inode)->i_flags & S_AUTOMOUNT)
295 #define IS_NOSEC(inode)         ((inode)->i_flags & S_NOSEC)
296 
297 /* the read-only stuff doesn't really belong here, but any other place is
298    probably as bad and I don't want to create yet another include file. */
299 
300 #define BLKROSET   _IO(0x12,93) /* set device read-only (0 = read-write) */
301 #define BLKROGET   _IO(0x12,94) /* get read-only status (0 = read_write) */
302 #define BLKRRPART  _IO(0x12,95) /* re-read partition table */
303 #define BLKGETSIZE _IO(0x12,96) /* return device size /512 (long *arg) */
304 #define BLKFLSBUF  _IO(0x12,97) /* flush buffer cache */
305 #define BLKRASET   _IO(0x12,98) /* set read ahead for block device */
306 #define BLKRAGET   _IO(0x12,99) /* get current read ahead setting */
307 #define BLKFRASET  _IO(0x12,100)/* set filesystem (mm/filemap.c) read-ahead */
308 #define BLKFRAGET  _IO(0x12,101)/* get filesystem (mm/filemap.c) read-ahead */
309 #define BLKSECTSET _IO(0x12,102)/* set max sectors per request (ll_rw_blk.c) */
310 #define BLKSECTGET _IO(0x12,103)/* get max sectors per request (ll_rw_blk.c) */
311 #define BLKSSZGET  _IO(0x12,104)/* get block device sector size */
312 #if 0
313 #define BLKPG      _IO(0x12,105)/* See blkpg.h */
314 
315 /* Some people are morons.  Do not use sizeof! */
316 
317 #define BLKELVGET  _IOR(0x12,106,size_t)/* elevator get */
318 #define BLKELVSET  _IOW(0x12,107,size_t)/* elevator set */
319 /* This was here just to show that the number is taken -
320    probably all these _IO(0x12,*) ioctls should be moved to blkpg.h. */
321 #endif
322 /* A jump here: 108-111 have been used for various private purposes. */
323 #define BLKBSZGET  _IOR(0x12,112,size_t)
324 #define BLKBSZSET  _IOW(0x12,113,size_t)
325 #define BLKGETSIZE64 _IOR(0x12,114,size_t)      /* return device size in bytes (u64 *arg) */
326 #define BLKTRACESETUP _IOWR(0x12,115,struct blk_user_trace_setup)
327 #define BLKTRACESTART _IO(0x12,116)
328 #define BLKTRACESTOP _IO(0x12,117)
329 #define BLKTRACETEARDOWN _IO(0x12,118)
330 #define BLKDISCARD _IO(0x12,119)
331 #define BLKIOMIN _IO(0x12,120)
332 #define BLKIOOPT _IO(0x12,121)
333 #define BLKALIGNOFF _IO(0x12,122)
334 #define BLKPBSZGET _IO(0x12,123)
335 #define BLKDISCARDZEROES _IO(0x12,124)
336 #define BLKSECDISCARD _IO(0x12,125)
337 #define BLKROTATIONAL _IO(0x12,126)
338 
339 #define BMAP_IOCTL 1            /* obsolete - kept for compatibility */
340 #define FIBMAP     _IO(0x00,1)  /* bmap access */
341 #define FIGETBSZ   _IO(0x00,2)  /* get the block size used for bmap */
342 #define FIFREEZE        _IOWR('X', 119, int)    /* Freeze */
343 #define FITHAW          _IOWR('X', 120, int)    /* Thaw */
344 #define FITRIM          _IOWR('X', 121, struct fstrim_range)    /* Trim */
345 
346 #define FS_IOC_GETFLAGS                 _IOR('f', 1, long)
347 #define FS_IOC_SETFLAGS                 _IOW('f', 2, long)
348 #define FS_IOC_GETVERSION               _IOR('v', 1, long)
349 #define FS_IOC_SETVERSION               _IOW('v', 2, long)
350 #define FS_IOC_FIEMAP                   _IOWR('f', 11, struct fiemap)
351 #define FS_IOC32_GETFLAGS               _IOR('f', 1, int)
352 #define FS_IOC32_SETFLAGS               _IOW('f', 2, int)
353 #define FS_IOC32_GETVERSION             _IOR('v', 1, int)
354 #define FS_IOC32_SETVERSION             _IOW('v', 2, int)
355 
356 /*
357  * Inode flags (FS_IOC_GETFLAGS / FS_IOC_SETFLAGS)
358  */
359 #define FS_SECRM_FL                     0x00000001 /* Secure deletion */
360 #define FS_UNRM_FL                      0x00000002 /* Undelete */
361 #define FS_COMPR_FL                     0x00000004 /* Compress file */
362 #define FS_SYNC_FL                      0x00000008 /* Synchronous updates */
363 #define FS_IMMUTABLE_FL                 0x00000010 /* Immutable file */
364 #define FS_APPEND_FL                    0x00000020 /* writes to file may only append */
365 #define FS_NODUMP_FL                    0x00000040 /* do not dump file */
366 #define FS_NOATIME_FL                   0x00000080 /* do not update atime */
367 /* Reserved for compression usage... */
368 #define FS_DIRTY_FL                     0x00000100
369 #define FS_COMPRBLK_FL                  0x00000200 /* One or more compressed clusters */
370 #define FS_NOCOMP_FL                    0x00000400 /* Don't compress */
371 #define FS_ECOMPR_FL                    0x00000800 /* Compression error */
372 /* End compression flags --- maybe not all used */
373 #define FS_BTREE_FL                     0x00001000 /* btree format dir */
374 #define FS_INDEX_FL                     0x00001000 /* hash-indexed directory */
375 #define FS_IMAGIC_FL                    0x00002000 /* AFS directory */
376 #define FS_JOURNAL_DATA_FL              0x00004000 /* Reserved for ext3 */
377 #define FS_NOTAIL_FL                    0x00008000 /* file tail should not be merged */
378 #define FS_DIRSYNC_FL                   0x00010000 /* dirsync behaviour (directories only) */
379 #define FS_TOPDIR_FL                    0x00020000 /* Top of directory hierarchies*/
380 #define FS_EXTENT_FL                    0x00080000 /* Extents */
381 #define FS_DIRECTIO_FL                  0x00100000 /* Use direct i/o */
382 #define FS_NOCOW_FL                     0x00800000 /* Do not cow file */
383 #define FS_RESERVED_FL                  0x80000000 /* reserved for ext2 lib */
384 
385 #define FS_FL_USER_VISIBLE              0x0003DFFF /* User visible flags */
386 #define FS_FL_USER_MODIFIABLE           0x000380FF /* User modifiable flags */
387 
388 
389 #define SYNC_FILE_RANGE_WAIT_BEFORE     1
390 #define SYNC_FILE_RANGE_WRITE           2
391 #define SYNC_FILE_RANGE_WAIT_AFTER      4
392 
393 #ifdef __KERNEL__
394 
395 #include <linux/linkage.h>
396 #include <linux/wait.h>
397 #include <linux/kdev_t.h>
398 #include <linux/dcache.h>
399 #include <linux/path.h>
400 #include <linux/stat.h>
401 #include <linux/cache.h>
402 #include <linux/list.h>
403 #include <linux/radix-tree.h>
404 #include <linux/prio_tree.h>
405 #include <linux/init.h>
406 #include <linux/pid.h>
407 #include <linux/bug.h>
408 #include <linux/mutex.h>
409 #include <linux/capability.h>
410 #include <linux/semaphore.h>
411 #include <linux/fiemap.h>
412 #include <linux/rculist_bl.h>
413 #include <linux/atomic.h>
414 #include <linux/shrinker.h>
415 #include <linux/migrate_mode.h>
416 #include <linux/uidgid.h>
417 #include <linux/lockdep.h>
418 
419 #include <asm/byteorder.h>
420 
421 struct export_operations;
422 struct hd_geometry;
423 struct iovec;
424 struct nameidata;
425 struct kiocb;
426 struct kobject;
427 struct pipe_inode_info;
428 struct poll_table_struct;
429 struct kstatfs;
430 struct vm_area_struct;
431 struct vfsmount;
432 struct cred;
433 struct swap_info_struct;
434 
435 extern void __init inode_init(void);
436 extern void __init inode_init_early(void);
437 extern void __init files_init(unsigned long);
438 
439 extern struct files_stat_struct files_stat;
440 extern unsigned long get_max_files(void);
441 extern int sysctl_nr_open;
442 extern struct inodes_stat_t inodes_stat;
443 extern int leases_enable, lease_break_time;
444 extern int sysctl_protected_symlinks;
445 extern int sysctl_protected_hardlinks;
446 
447 struct buffer_head;
448 typedef int (get_block_t)(struct inode *inode, sector_t iblock,
449                         struct buffer_head *bh_result, int create);
450 typedef void (dio_iodone_t)(struct kiocb *iocb, loff_t offset,
451                         ssize_t bytes, void *private, int ret,
452                         bool is_async);
453 
454 /*
455  * Attribute flags.  These should be or-ed together to figure out what
456  * has been changed!
457  */
458 #define ATTR_MODE       (1 << 0)
459 #define ATTR_UID        (1 << 1)
460 #define ATTR_GID        (1 << 2)
461 #define ATTR_SIZE       (1 << 3)
462 #define ATTR_ATIME      (1 << 4)
463 #define ATTR_MTIME      (1 << 5)
464 #define ATTR_CTIME      (1 << 6)
465 #define ATTR_ATIME_SET  (1 << 7)
466 #define ATTR_MTIME_SET  (1 << 8)
467 #define ATTR_FORCE      (1 << 9) /* Not a change, but a change it */
468 #define ATTR_ATTR_FLAG  (1 << 10)
469 #define ATTR_KILL_SUID  (1 << 11)
470 #define ATTR_KILL_SGID  (1 << 12)
471 #define ATTR_FILE       (1 << 13)
472 #define ATTR_KILL_PRIV  (1 << 14)
473 #define ATTR_OPEN       (1 << 15) /* Truncating from open(O_TRUNC) */
474 #define ATTR_TIMES_SET  (1 << 16)
475 
476 /*
477  * This is the Inode Attributes structure, used for notify_change().  It
478  * uses the above definitions as flags, to know which values have changed.
479  * Also, in this manner, a Filesystem can look at only the values it cares
480  * about.  Basically, these are the attributes that the VFS layer can
481  * request to change from the FS layer.
482  *
483  * Derek Atkins <warlord@MIT.EDU> 94-10-20
484  */
485 struct iattr {
486         unsigned int    ia_valid;
487         umode_t         ia_mode;
488         kuid_t          ia_uid;
489         kgid_t          ia_gid;
490         loff_t          ia_size;
491         struct timespec ia_atime;
492         struct timespec ia_mtime;
493         struct timespec ia_ctime;
494 
495         /*
496          * Not an attribute, but an auxiliary info for filesystems wanting to
497          * implement an ftruncate() like method.  NOTE: filesystem should
498          * check for (ia_valid & ATTR_FILE), and not for (ia_file != NULL).
499          */
500         struct file     *ia_file;
501 };
502 
503 /*
504  * Includes for diskquotas.
505  */
506 #include <linux/quota.h>
507 
508 /** 
509  * enum positive_aop_returns - aop return codes with specific semantics
510  *
511  * @AOP_WRITEPAGE_ACTIVATE: Informs the caller that page writeback has
512  *                          completed, that the page is still locked, and
513  *                          should be considered active.  The VM uses this hint
514  *                          to return the page to the active list -- it won't
515  *                          be a candidate for writeback again in the near
516  *                          future.  Other callers must be careful to unlock
517  *                          the page if they get this return.  Returned by
518  *                          writepage(); 
519  *
520  * @AOP_TRUNCATED_PAGE: The AOP method that was handed a locked page has
521  *                      unlocked it and the page might have been truncated.
522  *                      The caller should back up to acquiring a new page and
523  *                      trying again.  The aop will be taking reasonable
524  *                      precautions not to livelock.  If the caller held a page
525  *                      reference, it should drop it before retrying.  Returned
526  *                      by readpage().
527  *
528  * address_space_operation functions return these large constants to indicate
529  * special semantics to the caller.  These are much larger than the bytes in a
530  * page to allow for functions that return the number of bytes operated on in a
531  * given page.
532  */
533 
534 enum positive_aop_returns {
535         AOP_WRITEPAGE_ACTIVATE  = 0x80000,
536         AOP_TRUNCATED_PAGE      = 0x80001,
537 };
538 
539 #define AOP_FLAG_UNINTERRUPTIBLE        0x0001 /* will not do a short write */
540 #define AOP_FLAG_CONT_EXPAND            0x0002 /* called from cont_expand */
541 #define AOP_FLAG_NOFS                   0x0004 /* used by filesystem to direct
542                                                 * helper code (eg buffer layer)
543                                                 * to clear GFP_FS from alloc */
544 
545 /*
546  * oh the beauties of C type declarations.
547  */
548 struct page;
549 struct address_space;
550 struct writeback_control;
551 
552 struct iov_iter {
553         const struct iovec *iov;
554         unsigned long nr_segs;
555         size_t iov_offset;
556         size_t count;
557 };
558 
559 size_t iov_iter_copy_from_user_atomic(struct page *page,
560                 struct iov_iter *i, unsigned long offset, size_t bytes);
561 size_t iov_iter_copy_from_user(struct page *page,
562                 struct iov_iter *i, unsigned long offset, size_t bytes);
563 void iov_iter_advance(struct iov_iter *i, size_t bytes);
564 int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes);
565 size_t iov_iter_single_seg_count(struct iov_iter *i);
566 
567 static inline void iov_iter_init(struct iov_iter *i,
568                         const struct iovec *iov, unsigned long nr_segs,
569                         size_t count, size_t written)
570 {
571         i->iov = iov;
572         i->nr_segs = nr_segs;
573         i->iov_offset = 0;
574         i->count = count + written;
575 
576         iov_iter_advance(i, written);
577 }
578 
579 static inline size_t iov_iter_count(struct iov_iter *i)
580 {
581         return i->count;
582 }
583 
584 /*
585  * "descriptor" for what we're up to with a read.
586  * This allows us to use the same read code yet
587  * have multiple different users of the data that
588  * we read from a file.
589  *
590  * The simplest case just copies the data to user
591  * mode.
592  */
593 typedef struct {
594         size_t written;
595         size_t count;
596         union {
597                 char __user *buf;
598                 void *data;
599         } arg;
600         int error;
601 } read_descriptor_t;
602 
603 typedef int (*read_actor_t)(read_descriptor_t *, struct page *,
604                 unsigned long, unsigned long);
605 
606 struct address_space_operations {
607         int (*writepage)(struct page *page, struct writeback_control *wbc);
608         int (*readpage)(struct file *, struct page *);
609 
610         /* Write back some dirty pages from this mapping. */
611         int (*writepages)(struct address_space *, struct writeback_control *);
612 
613         /* Set a page dirty.  Return true if this dirtied it */
614         int (*set_page_dirty)(struct page *page);
615 
616         int (*readpages)(struct file *filp, struct address_space *mapping,
617                         struct list_head *pages, unsigned nr_pages);
618 
619         int (*write_begin)(struct file *, struct address_space *mapping,
620                                 loff_t pos, unsigned len, unsigned flags,
621                                 struct page **pagep, void **fsdata);
622         int (*write_end)(struct file *, struct address_space *mapping,
623                                 loff_t pos, unsigned len, unsigned copied,
624                                 struct page *page, void *fsdata);
625 
626         /* Unfortunately this kludge is needed for FIBMAP. Don't use it */
627         sector_t (*bmap)(struct address_space *, sector_t);
628         void (*invalidatepage) (struct page *, unsigned long);
629         int (*releasepage) (struct page *, gfp_t);
630         void (*freepage)(struct page *);
631         ssize_t (*direct_IO)(int, struct kiocb *, const struct iovec *iov,
632                         loff_t offset, unsigned long nr_segs);
633         int (*get_xip_mem)(struct address_space *, pgoff_t, int,
634                                                 void **, unsigned long *);
635         /*
636          * migrate the contents of a page to the specified target. If sync
637          * is false, it must not block.
638          */
639         int (*migratepage) (struct address_space *,
640                         struct page *, struct page *, enum migrate_mode);
641         int (*launder_page) (struct page *);
642         int (*is_partially_uptodate) (struct page *, read_descriptor_t *,
643                                         unsigned long);
644         int (*error_remove_page)(struct address_space *, struct page *);
645 
646         /* swapfile support */
647         int (*swap_activate)(struct swap_info_struct *sis, struct file *file,
648                                 sector_t *span);
649         void (*swap_deactivate)(struct file *file);
650 };
651 
652 extern const struct address_space_operations empty_aops;
653 
654 /*
655  * pagecache_write_begin/pagecache_write_end must be used by general code
656  * to write into the pagecache.
657  */
658 int pagecache_write_begin(struct file *, struct address_space *mapping,
659                                 loff_t pos, unsigned len, unsigned flags,
660                                 struct page **pagep, void **fsdata);
661 
662 int pagecache_write_end(struct file *, struct address_space *mapping,
663                                 loff_t pos, unsigned len, unsigned copied,
664                                 struct page *page, void *fsdata);
665 
666 struct backing_dev_info;
667 struct address_space {
668         struct inode            *host;          /* owner: inode, block_device */
669         struct radix_tree_root  page_tree;      /* radix tree of all pages */
670         spinlock_t              tree_lock;      /* and lock protecting it */
671         unsigned int            i_mmap_writable;/* count VM_SHARED mappings */
672         struct prio_tree_root   i_mmap;         /* tree of private and shared mappings */
673         struct list_head        i_mmap_nonlinear;/*list VM_NONLINEAR mappings */
674         struct mutex            i_mmap_mutex;   /* protect tree, count, list */
675         /* Protected by tree_lock together with the radix tree */
676         unsigned long           nrpages;        /* number of total pages */
677         pgoff_t                 writeback_index;/* writeback starts here */
678         const struct address_space_operations *a_ops;   /* methods */
679         unsigned long           flags;          /* error bits/gfp mask */
680         struct backing_dev_info *backing_dev_info; /* device readahead, etc */
681         spinlock_t              private_lock;   /* for use by the address_space */
682         struct list_head        private_list;   /* ditto */
683         struct address_space    *assoc_mapping; /* ditto */
684 } __attribute__((aligned(sizeof(long))));
685         /*
686          * On most architectures that alignment is already the case; but
687          * must be enforced here for CRIS, to let the least significant bit
688          * of struct page's "mapping" pointer be used for PAGE_MAPPING_ANON.
689          */
690 struct request_queue;
691 
692 struct block_device {
693         dev_t                   bd_dev;  /* not a kdev_t - it's a search key */
694         int                     bd_openers;
695         struct inode *          bd_inode;       /* will die */
696         struct super_block *    bd_super;
697         struct mutex            bd_mutex;       /* open/close mutex */
698         struct list_head        bd_inodes;
699         void *                  bd_claiming;
700         void *                  bd_holder;
701         int                     bd_holders;
702         bool                    bd_write_holder;
703 #ifdef CONFIG_SYSFS
704         struct list_head        bd_holder_disks;
705 #endif
706         struct block_device *   bd_contains;
707         unsigned                bd_block_size;
708         struct hd_struct *      bd_part;
709         /* number of times partitions within this device have been opened. */
710         unsigned                bd_part_count;
711         int                     bd_invalidated;
712         struct gendisk *        bd_disk;
713         struct request_queue *  bd_queue;
714         struct list_head        bd_list;
715         /*
716          * Private data.  You must have bd_claim'ed the block_device
717          * to use this.  NOTE:  bd_claim allows an owner to claim
718          * the same device multiple times, the owner must take special
719          * care to not mess up bd_private for that case.
720          */
721         unsigned long           bd_private;
722 
723         /* The counter of freeze processes */
724         int                     bd_fsfreeze_count;
725         /* Mutex for freeze */
726         struct mutex            bd_fsfreeze_mutex;
727 };
728 
729 /*
730  * Radix-tree tags, for tagging dirty and writeback pages within the pagecache
731  * radix trees
732  */
733 #define PAGECACHE_TAG_DIRTY     0
734 #define PAGECACHE_TAG_WRITEBACK 1
735 #define PAGECACHE_TAG_TOWRITE   2
736 
737 int mapping_tagged(struct address_space *mapping, int tag);
738 
739 /*
740  * Might pages of this file be mapped into userspace?
741  */
742 static inline int mapping_mapped(struct address_space *mapping)
743 {
744         return  !prio_tree_empty(&mapping->i_mmap) ||
745                 !list_empty(&mapping->i_mmap_nonlinear);
746 }
747 
748 /*
749  * Might pages of this file have been modified in userspace?
750  * Note that i_mmap_writable counts all VM_SHARED vmas: do_mmap_pgoff
751  * marks vma as VM_SHARED if it is shared, and the file was opened for
752  * writing i.e. vma may be mprotected writable even if now readonly.
753  */
754 static inline int mapping_writably_mapped(struct address_space *mapping)
755 {
756         return mapping->i_mmap_writable != 0;
757 }
758 
759 /*
760  * Use sequence counter to get consistent i_size on 32-bit processors.
761  */
762 #if BITS_PER_LONG==32 && defined(CONFIG_SMP)
763 #include <linux/seqlock.h>
764 #define __NEED_I_SIZE_ORDERED
765 #define i_size_ordered_init(inode) seqcount_init(&inode->i_size_seqcount)
766 #else
767 #define i_size_ordered_init(inode) do { } while (0)
768 #endif
769 
770 struct posix_acl;
771 #define ACL_NOT_CACHED ((void *)(-1))
772 
773 #define IOP_FASTPERM    0x0001
774 #define IOP_LOOKUP      0x0002
775 #define IOP_NOFOLLOW    0x0004
776 
777 /*
778  * Keep mostly read-only and often accessed (especially for
779  * the RCU path lookup and 'stat' data) fields at the beginning
780  * of the 'struct inode'
781  */
782 struct inode {
783         umode_t                 i_mode;
784         unsigned short          i_opflags;
785         kuid_t                  i_uid;
786         kgid_t                  i_gid;
787         unsigned int            i_flags;
788 
789 #ifdef CONFIG_FS_POSIX_ACL
790         struct posix_acl        *i_acl;
791         struct posix_acl        *i_default_acl;
792 #endif
793 
794         const struct inode_operations   *i_op;
795         struct super_block      *i_sb;
796         struct address_space    *i_mapping;
797 
798 #ifdef CONFIG_SECURITY
799         void                    *i_security;
800 #endif
801 
802         /* Stat data, not accessed from path walking */
803         unsigned long           i_ino;
804         /*
805          * Filesystems may only read i_nlink directly.  They shall use the
806          * following functions for modification:
807          *
808          *    (set|clear|inc|drop)_nlink
809          *    inode_(inc|dec)_link_count
810          */
811         union {
812                 const unsigned int i_nlink;
813                 unsigned int __i_nlink;
814         };
815         dev_t                   i_rdev;
816         loff_t                  i_size;
817         struct timespec         i_atime;
818         struct timespec         i_mtime;
819         struct timespec         i_ctime;
820         spinlock_t              i_lock; /* i_blocks, i_bytes, maybe i_size */
821         unsigned short          i_bytes;
822         unsigned int            i_blkbits;
823         blkcnt_t                i_blocks;
824 
825 #ifdef __NEED_I_SIZE_ORDERED
826         seqcount_t              i_size_seqcount;
827 #endif
828 
829         /* Misc */
830         unsigned long           i_state;
831         struct mutex            i_mutex;
832 
833         unsigned long           dirtied_when;   /* jiffies of first dirtying */
834 
835         struct hlist_node       i_hash;
836         struct list_head        i_wb_list;      /* backing dev IO list */
837         struct list_head        i_lru;          /* inode LRU list */
838         struct list_head        i_sb_list;
839         union {
840                 struct hlist_head       i_dentry;
841                 struct rcu_head         i_rcu;
842         };
843         u64                     i_version;
844         atomic_t                i_count;
845         atomic_t                i_dio_count;
846         atomic_t                i_writecount;
847         const struct file_operations    *i_fop; /* former ->i_op->default_file_ops */
848         struct file_lock        *i_flock;
849         struct address_space    i_data;
850 #ifdef CONFIG_QUOTA
851         struct dquot            *i_dquot[MAXQUOTAS];
852 #endif
853         struct list_head        i_devices;
854         union {
855                 struct pipe_inode_info  *i_pipe;
856                 struct block_device     *i_bdev;
857                 struct cdev             *i_cdev;
858         };
859 
860         __u32                   i_generation;
861 
862 #ifdef CONFIG_FSNOTIFY
863         __u32                   i_fsnotify_mask; /* all events this inode cares about */
864         struct hlist_head       i_fsnotify_marks;
865 #endif
866 
867 #ifdef CONFIG_IMA
868         atomic_t                i_readcount; /* struct files open RO */
869 #endif
870         void                    *i_private; /* fs or device private pointer */
871 };
872 
873 static inline int inode_unhashed(struct inode *inode)
874 {
875         return hlist_unhashed(&inode->i_hash);
876 }
877 
878 /*
879  * inode->i_mutex nesting subclasses for the lock validator:
880  *
881  * 0: the object of the current VFS operation
882  * 1: parent
883  * 2: child/target
884  * 3: quota file
885  *
886  * The locking order between these classes is
887  * parent -> child -> normal -> xattr -> quota
888  */
889 enum inode_i_mutex_lock_class
890 {
891         I_MUTEX_NORMAL,
892         I_MUTEX_PARENT,
893         I_MUTEX_CHILD,
894         I_MUTEX_XATTR,
895         I_MUTEX_QUOTA
896 };
897 
898 /*
899  * NOTE: in a 32bit arch with a preemptable kernel and
900  * an UP compile the i_size_read/write must be atomic
901  * with respect to the local cpu (unlike with preempt disabled),
902  * but they don't need to be atomic with respect to other cpus like in
903  * true SMP (so they need either to either locally disable irq around
904  * the read or for example on x86 they can be still implemented as a
905  * cmpxchg8b without the need of the lock prefix). For SMP compiles
906  * and 64bit archs it makes no difference if preempt is enabled or not.
907  */
908 static inline loff_t i_size_read(const struct inode *inode)
909 {
910 #if BITS_PER_LONG==32 && defined(CONFIG_SMP)
911         loff_t i_size;
912         unsigned int seq;
913 
914         do {
915                 seq = read_seqcount_begin(&inode->i_size_seqcount);
916                 i_size = inode->i_size;
917         } while (read_seqcount_retry(&inode->i_size_seqcount, seq));
918         return i_size;
919 #elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPT)
920         loff_t i_size;
921 
922         preempt_disable();
923         i_size = inode->i_size;
924         preempt_enable();
925         return i_size;
926 #else
927         return inode->i_size;
928 #endif
929 }
930 
931 /*
932  * NOTE: unlike i_size_read(), i_size_write() does need locking around it
933  * (normally i_mutex), otherwise on 32bit/SMP an update of i_size_seqcount
934  * can be lost, resulting in subsequent i_size_read() calls spinning forever.
935  */
936 static inline void i_size_write(struct inode *inode, loff_t i_size)
937 {
938 #if BITS_PER_LONG==32 && defined(CONFIG_SMP)
939         write_seqcount_begin(&inode->i_size_seqcount);
940         inode->i_size = i_size;
941         write_seqcount_end(&inode->i_size_seqcount);
942 #elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPT)
943         preempt_disable();
944         inode->i_size = i_size;
945         preempt_enable();
946 #else
947         inode->i_size = i_size;
948 #endif
949 }
950 
951 /* Helper functions so that in most cases filesystems will
952  * not need to deal directly with kuid_t and kgid_t and can
953  * instead deal with the raw numeric values that are stored
954  * in the filesystem.
955  */
956 static inline uid_t i_uid_read(const struct inode *inode)
957 {
958         return from_kuid(&init_user_ns, inode->i_uid);
959 }
960 
961 static inline gid_t i_gid_read(const struct inode *inode)
962 {
963         return from_kgid(&init_user_ns, inode->i_gid);
964 }
965 
966 static inline void i_uid_write(struct inode *inode, uid_t uid)
967 {
968         inode->i_uid = make_kuid(&init_user_ns, uid);
969 }
970 
971 static inline void i_gid_write(struct inode *inode, gid_t gid)
972 {
973         inode->i_gid = make_kgid(&init_user_ns, gid);
974 }
975 
976 static inline unsigned iminor(const struct inode *inode)
977 {
978         return MINOR(inode->i_rdev);
979 }
980 
981 static inline unsigned imajor(const struct inode *inode)
982 {
983         return MAJOR(inode->i_rdev);
984 }
985 
986 extern struct block_device *I_BDEV(struct inode *inode);
987 
988 struct fown_struct {
989         rwlock_t lock;          /* protects pid, uid, euid fields */
990         struct pid *pid;        /* pid or -pgrp where SIGIO should be sent */
991         enum pid_type pid_type; /* Kind of process group SIGIO should be sent to */
992         kuid_t uid, euid;       /* uid/euid of process setting the owner */
993         int signum;             /* posix.1b rt signal to be delivered on IO */
994 };
995 
996 /*
997  * Track a single file's readahead state
998  */
999 struct file_ra_state {
1000         pgoff_t start;                  /* where readahead started */
1001         unsigned int size;              /* # of readahead pages */
1002         unsigned int async_size;        /* do asynchronous readahead when
1003                                            there are only # of pages ahead */
1004 
1005         unsigned int ra_pages;          /* Maximum readahead window */
1006         unsigned int mmap_miss;         /* Cache miss stat for mmap accesses */
1007         loff_t prev_pos;                /* Cache last read() position */
1008 };
1009 
1010 /*
1011  * Check if @index falls in the readahead windows.
1012  */
1013 static inline int ra_has_index(struct file_ra_state *ra, pgoff_t index)
1014 {
1015         return (index >= ra->start &&
1016                 index <  ra->start + ra->size);
1017 }
1018 
1019 #define FILE_MNT_WRITE_TAKEN    1
1020 #define FILE_MNT_WRITE_RELEASED 2
1021 
1022 struct file {
1023         /*
1024          * fu_list becomes invalid after file_free is called and queued via
1025          * fu_rcuhead for RCU freeing
1026          */
1027         union {
1028                 struct list_head        fu_list;
1029                 struct rcu_head         fu_rcuhead;
1030         } f_u;
1031         struct path             f_path;
1032 #define f_dentry        f_path.dentry
1033 #define f_vfsmnt        f_path.mnt
1034         const struct file_operations    *f_op;
1035 
1036         /*
1037          * Protects f_ep_links, f_flags, f_pos vs i_size in lseek SEEK_CUR.
1038          * Must not be taken from IRQ context.
1039          */
1040         spinlock_t              f_lock;
1041 #ifdef CONFIG_SMP
1042         int                     f_sb_list_cpu;
1043 #endif
1044         atomic_long_t           f_count;
1045         unsigned int            f_flags;
1046         fmode_t                 f_mode;
1047         loff_t                  f_pos;
1048         struct fown_struct      f_owner;
1049         const struct cred       *f_cred;
1050         struct file_ra_state    f_ra;
1051 
1052         u64                     f_version;
1053 #ifdef CONFIG_SECURITY
1054         void                    *f_security;
1055 #endif
1056         /* needed for tty driver, and maybe others */
1057         void                    *private_data;
1058 
1059 #ifdef CONFIG_EPOLL
1060         /* Used by fs/eventpoll.c to link all the hooks to this file */
1061         struct list_head        f_ep_links;
1062         struct list_head        f_tfile_llink;
1063 #endif /* #ifdef CONFIG_EPOLL */
1064         struct address_space    *f_mapping;
1065 #ifdef CONFIG_DEBUG_WRITECOUNT
1066         unsigned long f_mnt_write_state;
1067 #endif
1068 };
1069 
1070 struct file_handle {
1071         __u32 handle_bytes;
1072         int handle_type;
1073         /* file identifier */
1074         unsigned char f_handle[0];
1075 };
1076 
1077 #define get_file(x)     atomic_long_inc(&(x)->f_count)
1078 #define fput_atomic(x)  atomic_long_add_unless(&(x)->f_count, -1, 1)
1079 #define file_count(x)   atomic_long_read(&(x)->f_count)
1080 
1081 #ifdef CONFIG_DEBUG_WRITECOUNT
1082 static inline void file_take_write(struct file *f)
1083 {
1084         WARN_ON(f->f_mnt_write_state != 0);
1085         f->f_mnt_write_state = FILE_MNT_WRITE_TAKEN;
1086 }
1087 static inline void file_release_write(struct file *f)
1088 {
1089         f->f_mnt_write_state |= FILE_MNT_WRITE_RELEASED;
1090 }
1091 static inline void file_reset_write(struct file *f)
1092 {
1093         f->f_mnt_write_state = 0;
1094 }
1095 static inline void file_check_state(struct file *f)
1096 {
1097         /*
1098          * At this point, either both or neither of these bits
1099          * should be set.
1100          */
1101         WARN_ON(f->f_mnt_write_state == FILE_MNT_WRITE_TAKEN);
1102         WARN_ON(f->f_mnt_write_state == FILE_MNT_WRITE_RELEASED);
1103 }
1104 static inline int file_check_writeable(struct file *f)
1105 {
1106         if (f->f_mnt_write_state == FILE_MNT_WRITE_TAKEN)
1107                 return 0;
1108         printk(KERN_WARNING "writeable file with no "
1109                             "mnt_want_write()\n");
1110         WARN_ON(1);
1111         return -EINVAL;
1112 }
1113 #else /* !CONFIG_DEBUG_WRITECOUNT */
1114 static inline void file_take_write(struct file *filp) {}
1115 static inline void file_release_write(struct file *filp) {}
1116 static inline void file_reset_write(struct file *filp) {}
1117 static inline void file_check_state(struct file *filp) {}
1118 static inline int file_check_writeable(struct file *filp)
1119 {
1120         return 0;
1121 }
1122 #endif /* CONFIG_DEBUG_WRITECOUNT */
1123 
1124 #define MAX_NON_LFS     ((1UL<<31) - 1)
1125 
1126 /* Page cache limit. The filesystems should put that into their s_maxbytes 
1127    limits, otherwise bad things can happen in VM. */ 
1128 #if BITS_PER_LONG==32
1129 #define MAX_LFS_FILESIZE        (((u64)PAGE_CACHE_SIZE << (BITS_PER_LONG-1))-1) 
1130 #elif BITS_PER_LONG==64
1131 #define MAX_LFS_FILESIZE        0x7fffffffffffffffUL
1132 #endif
1133 
1134 #define FL_POSIX        1
1135 #define FL_FLOCK        2
1136 #define FL_ACCESS       8       /* not trying to lock, just looking */
1137 #define FL_EXISTS       16      /* when unlocking, test for existence */
1138 #define FL_LEASE        32      /* lease held on this file */
1139 #define FL_CLOSE        64      /* unlock on close */
1140 #define FL_SLEEP        128     /* A blocking lock */
1141 #define FL_DOWNGRADE_PENDING    256 /* Lease is being downgraded */
1142 #define FL_UNLOCK_PENDING       512 /* Lease is being broken */
1143 
1144 /*
1145  * Special return value from posix_lock_file() and vfs_lock_file() for
1146  * asynchronous locking.
1147  */
1148 #define FILE_LOCK_DEFERRED 1
1149 
1150 /*
1151  * The POSIX file lock owner is determined by
1152  * the "struct files_struct" in the thread group
1153  * (or NULL for no owner - BSD locks).
1154  *
1155  * Lockd stuffs a "host" pointer into this.
1156  */
1157 typedef struct files_struct *fl_owner_t;
1158 
1159 struct file_lock_operations {
1160         void (*fl_copy_lock)(struct file_lock *, struct file_lock *);
1161         void (*fl_release_private)(struct file_lock *);
1162 };
1163 
1164 struct lock_manager_operations {
1165         int (*lm_compare_owner)(struct file_lock *, struct file_lock *);
1166         void (*lm_notify)(struct file_lock *);  /* unblock callback */
1167         int (*lm_grant)(struct file_lock *, struct file_lock *, int);
1168         void (*lm_break)(struct file_lock *);
1169         int (*lm_change)(struct file_lock **, int);
1170 };
1171 
1172 struct lock_manager {
1173         struct list_head list;
1174 };
1175 
1176 struct net;
1177 void locks_start_grace(struct net *, struct lock_manager *);
1178 void locks_end_grace(struct lock_manager *);
1179 int locks_in_grace(struct net *);
1180 
1181 /* that will die - we need it for nfs_lock_info */
1182 #include <linux/nfs_fs_i.h>
1183 
1184 struct file_lock {
1185         struct file_lock *fl_next;      /* singly linked list for this inode  */
1186         struct list_head fl_link;       /* doubly linked list of all locks */
1187         struct list_head fl_block;      /* circular list of blocked processes */
1188         fl_owner_t fl_owner;
1189         unsigned int fl_flags;
1190         unsigned char fl_type;
1191         unsigned int fl_pid;
1192         struct pid *fl_nspid;
1193         wait_queue_head_t fl_wait;
1194         struct file *fl_file;
1195         loff_t fl_start;
1196         loff_t fl_end;
1197 
1198         struct fasync_struct *  fl_fasync; /* for lease break notifications */
1199         /* for lease breaks: */
1200         unsigned long fl_break_time;
1201         unsigned long fl_downgrade_time;
1202 
1203         const struct file_lock_operations *fl_ops;      /* Callbacks for filesystems */
1204         const struct lock_manager_operations *fl_lmops; /* Callbacks for lockmanagers */
1205         union {
1206                 struct nfs_lock_info    nfs_fl;
1207                 struct nfs4_lock_info   nfs4_fl;
1208                 struct {
1209                         struct list_head link;  /* link in AFS vnode's pending_locks list */
1210                         int state;              /* state of grant or error if -ve */
1211                 } afs;
1212         } fl_u;
1213 };
1214 
1215 /* The following constant reflects the upper bound of the file/locking space */
1216 #ifndef OFFSET_MAX
1217 #define INT_LIMIT(x)    (~((x)1 << (sizeof(x)*8 - 1)))
1218 #define OFFSET_MAX      INT_LIMIT(loff_t)
1219 #define OFFT_OFFSET_MAX INT_LIMIT(off_t)
1220 #endif
1221 
1222 #include <linux/fcntl.h>
1223 
1224 extern void send_sigio(struct fown_struct *fown, int fd, int band);
1225 
1226 #ifdef CONFIG_FILE_LOCKING
1227 extern int fcntl_getlk(struct file *, struct flock __user *);
1228 extern int fcntl_setlk(unsigned int, struct file *, unsigned int,
1229                         struct flock __user *);
1230 
1231 #if BITS_PER_LONG == 32
1232 extern int fcntl_getlk64(struct file *, struct flock64 __user *);
1233 extern int fcntl_setlk64(unsigned int, struct file *, unsigned int,
1234                         struct flock64 __user *);
1235 #endif
1236 
1237 extern int fcntl_setlease(unsigned int fd, struct file *filp, long arg);
1238 extern int fcntl_getlease(struct file *filp);
1239 
1240 /* fs/locks.c */
1241 void locks_free_lock(struct file_lock *fl);
1242 extern void locks_init_lock(struct file_lock *);
1243 extern struct file_lock * locks_alloc_lock(void);
1244 extern void locks_copy_lock(struct file_lock *, struct file_lock *);
1245 extern void __locks_copy_lock(struct file_lock *, const struct file_lock *);
1246 extern void locks_remove_posix(struct file *, fl_owner_t);
1247 extern void locks_remove_flock(struct file *);
1248 extern void locks_release_private(struct file_lock *);
1249 extern void posix_test_lock(struct file *, struct file_lock *);
1250 extern int posix_lock_file(struct file *, struct file_lock *, struct file_lock *);
1251 extern int posix_lock_file_wait(struct file *, struct file_lock *);
1252 extern int posix_unblock_lock(struct file *, struct file_lock *);
1253 extern int vfs_test_lock(struct file *, struct file_lock *);
1254 extern int vfs_lock_file(struct file *, unsigned int, struct file_lock *, struct file_lock *);
1255 extern int vfs_cancel_lock(struct file *filp, struct file_lock *fl);
1256 extern int flock_lock_file_wait(struct file *filp, struct file_lock *fl);
1257 extern int __break_lease(struct inode *inode, unsigned int flags);
1258 extern void lease_get_mtime(struct inode *, struct timespec *time);
1259 extern int generic_setlease(struct file *, long, struct file_lock **);
1260 extern int vfs_setlease(struct file *, long, struct file_lock **);
1261 extern int lease_modify(struct file_lock **, int);
1262 extern int lock_may_read(struct inode *, loff_t start, unsigned long count);
1263 extern int lock_may_write(struct inode *, loff_t start, unsigned long count);
1264 extern void locks_delete_block(struct file_lock *waiter);
1265 extern void lock_flocks(void);
1266 extern void unlock_flocks(void);
1267 #else /* !CONFIG_FILE_LOCKING */
1268 static inline int fcntl_getlk(struct file *file, struct flock __user *user)
1269 {
1270         return -EINVAL;
1271 }
1272 
1273 static inline int fcntl_setlk(unsigned int fd, struct file *file,
1274                               unsigned int cmd, struct flock __user *user)
1275 {
1276         return -EACCES;
1277 }
1278 
1279 #if BITS_PER_LONG == 32
1280 static inline int fcntl_getlk64(struct file *file, struct flock64 __user *user)
1281 {
1282         return -EINVAL;
1283 }
1284 
1285 static inline int fcntl_setlk64(unsigned int fd, struct file *file,
1286                                 unsigned int cmd, struct flock64 __user *user)
1287 {
1288         return -EACCES;
1289 }
1290 #endif
1291 static inline int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
1292 {
1293         return 0;
1294 }
1295 
1296 static inline int fcntl_getlease(struct file *filp)
1297 {
1298         return 0;
1299 }
1300 
1301 static inline void locks_init_lock(struct file_lock *fl)
1302 {
1303         return;
1304 }
1305 
1306 static inline void __locks_copy_lock(struct file_lock *new, struct file_lock *fl)
1307 {
1308         return;
1309 }
1310 
1311 static inline void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
1312 {
1313         return;
1314 }
1315 
1316 static inline void locks_remove_posix(struct file *filp, fl_owner_t owner)
1317 {
1318         return;
1319 }
1320 
1321 static inline void locks_remove_flock(struct file *filp)
1322 {
1323         return;
1324 }
1325 
1326 static inline void posix_test_lock(struct file *filp, struct file_lock *fl)
1327 {
1328         return;
1329 }
1330 
1331 static inline int posix_lock_file(struct file *filp, struct file_lock *fl,
1332                                   struct file_lock *conflock)
1333 {
1334         return -ENOLCK;
1335 }
1336 
1337 static inline int posix_lock_file_wait(struct file *filp, struct file_lock *fl)
1338 {
1339         return -ENOLCK;
1340 }
1341 
1342 static inline int posix_unblock_lock(struct file *filp,
1343                                      struct file_lock *waiter)
1344 {
1345         return -ENOENT;
1346 }
1347 
1348 static inline int vfs_test_lock(struct file *filp, struct file_lock *fl)
1349 {
1350         return 0;
1351 }
1352 
1353 static inline int vfs_lock_file(struct file *filp, unsigned int cmd,
1354                                 struct file_lock *fl, struct file_lock *conf)
1355 {
1356         return -ENOLCK;
1357 }
1358 
1359 static inline int vfs_cancel_lock(struct file *filp, struct file_lock *fl)
1360 {
1361         return 0;
1362 }
1363 
1364 static inline int flock_lock_file_wait(struct file *filp,
1365                                        struct file_lock *request)
1366 {
1367         return -ENOLCK;
1368 }
1369 
1370 static inline int __break_lease(struct inode *inode, unsigned int mode)
1371 {
1372         return 0;
1373 }
1374 
1375 static inline void lease_get_mtime(struct inode *inode, struct timespec *time)
1376 {
1377         return;
1378 }
1379 
1380 static inline int generic_setlease(struct file *filp, long arg,
1381                                     struct file_lock **flp)
1382 {
1383         return -EINVAL;
1384 }
1385 
1386 static inline int vfs_setlease(struct file *filp, long arg,
1387                                struct file_lock **lease)
1388 {
1389         return -EINVAL;
1390 }
1391 
1392 static inline int lease_modify(struct file_lock **before, int arg)
1393 {
1394         return -EINVAL;
1395 }
1396 
1397 static inline int lock_may_read(struct inode *inode, loff_t start,
1398                                 unsigned long len)
1399 {
1400         return 1;
1401 }
1402 
1403 static inline int lock_may_write(struct inode *inode, loff_t start,
1404                                  unsigned long len)
1405 {
1406         return 1;
1407 }
1408 
1409 static inline void locks_delete_block(struct file_lock *waiter)
1410 {
1411 }
1412 
1413 static inline void lock_flocks(void)
1414 {
1415 }
1416 
1417 static inline void unlock_flocks(void)
1418 {
1419 }
1420 
1421 #endif /* !CONFIG_FILE_LOCKING */
1422 
1423 
1424 struct fasync_struct {
1425         spinlock_t              fa_lock;
1426         int                     magic;
1427         int                     fa_fd;
1428         struct fasync_struct    *fa_next; /* singly linked list */
1429         struct file             *fa_file;
1430         struct rcu_head         fa_rcu;
1431 };
1432 
1433 #define FASYNC_MAGIC 0x4601
1434 
1435 /* SMP safe fasync helpers: */
1436 extern int fasync_helper(int, struct file *, int, struct fasync_struct **);
1437 extern struct fasync_struct *fasync_insert_entry(int, struct file *, struct fasync_struct **, struct fasync_struct *);
1438 extern int fasync_remove_entry(struct file *, struct fasync_struct **);
1439 extern struct fasync_struct *fasync_alloc(void);
1440 extern void fasync_free(struct fasync_struct *);
1441 
1442 /* can be called from interrupts */
1443 extern void kill_fasync(struct fasync_struct **, int, int);
1444 
1445 extern int __f_setown(struct file *filp, struct pid *, enum pid_type, int force);
1446 extern int f_setown(struct file *filp, unsigned long arg, int force);
1447 extern void f_delown(struct file *filp);
1448 extern pid_t f_getown(struct file *filp);
1449 extern int send_sigurg(struct fown_struct *fown);
1450 
1451 struct mm_struct;
1452 
1453 /*
1454  *      Umount options
1455  */
1456 
1457 #define MNT_FORCE       0x00000001      /* Attempt to forcibily umount */
1458 #define MNT_DETACH      0x00000002      /* Just detach from the tree */
1459 #define MNT_EXPIRE      0x00000004      /* Mark for expiry */
1460 #define UMOUNT_NOFOLLOW 0x00000008      /* Don't follow symlink on umount */
1461 #define UMOUNT_UNUSED   0x80000000      /* Flag guaranteed to be unused */
1462 
1463 extern struct list_head super_blocks;
1464 extern spinlock_t sb_lock;
1465 
1466 /* Possible states of 'frozen' field */
1467 enum {
1468         SB_UNFROZEN = 0,                /* FS is unfrozen */
1469         SB_FREEZE_WRITE = 1,            /* Writes, dir ops, ioctls frozen */
1470         SB_FREEZE_PAGEFAULT = 2,        /* Page faults stopped as well */
1471         SB_FREEZE_FS = 3,               /* For internal FS use (e.g. to stop
1472                                          * internal threads if needed) */
1473         SB_FREEZE_COMPLETE = 4,         /* ->freeze_fs finished successfully */
1474 };
1475 
1476 #define SB_FREEZE_LEVELS (SB_FREEZE_COMPLETE - 1)
1477 
1478 struct sb_writers {
1479         /* Counters for counting writers at each level */
1480         struct percpu_counter   counter[SB_FREEZE_LEVELS];
1481         wait_queue_head_t       wait;           /* queue for waiting for
1482                                                    writers / faults to finish */
1483         int                     frozen;         /* Is sb frozen? */
1484         wait_queue_head_t       wait_unfrozen;  /* queue for waiting for
1485                                                    sb to be thawed */
1486 #ifdef CONFIG_DEBUG_LOCK_ALLOC
1487         struct lockdep_map      lock_map[SB_FREEZE_LEVELS];
1488 #endif
1489 };
1490 
1491 struct super_block {
1492         struct list_head        s_list;         /* Keep this first */
1493         dev_t                   s_dev;          /* search index; _not_ kdev_t */
1494         unsigned char           s_blocksize_bits;
1495         unsigned long           s_blocksize;
1496         loff_t                  s_maxbytes;     /* Max file size */
1497         struct file_system_type *s_type;
1498         const struct super_operations   *s_op;
1499         const struct dquot_operations   *dq_op;
1500         const struct quotactl_ops       *s_qcop;
1501         const struct export_operations *s_export_op;
1502         unsigned long           s_flags;
1503         unsigned long           s_magic;
1504         struct dentry           *s_root;
1505         struct rw_semaphore     s_umount;
1506         struct mutex            s_lock;
1507         int                     s_count;
1508         atomic_t                s_active;
1509 #ifdef CONFIG_SECURITY
1510         void                    *s_security;
1511 #endif
1512         const struct xattr_handler **s_xattr;
1513 
1514         struct list_head        s_inodes;       /* all inodes */
1515         struct hlist_bl_head    s_anon;         /* anonymous dentries for (nfs) exporting */
1516 #ifdef CONFIG_SMP
1517         struct list_head __percpu *s_files;
1518 #else
1519         struct list_head        s_files;
1520 #endif
1521         struct list_head        s_mounts;       /* list of mounts; _not_ for fs use */
1522         /* s_dentry_lru, s_nr_dentry_unused protected by dcache.c lru locks */
1523         struct list_head        s_dentry_lru;   /* unused dentry lru */
1524         int                     s_nr_dentry_unused;     /* # of dentry on lru */
1525 
1526         /* s_inode_lru_lock protects s_inode_lru and s_nr_inodes_unused */
1527         spinlock_t              s_inode_lru_lock ____cacheline_aligned_in_smp;
1528         struct list_head        s_inode_lru;            /* unused inode lru */
1529         int                     s_nr_inodes_unused;     /* # of inodes on lru */
1530 
1531         struct block_device     *s_bdev;
1532         struct backing_dev_info *s_bdi;
1533         struct mtd_info         *s_mtd;
1534         struct hlist_node       s_instances;
1535         struct quota_info       s_dquot;        /* Diskquota specific options */
1536 
1537         struct sb_writers       s_writers;
1538 
1539         char s_id[32];                          /* Informational name */
1540         u8 s_uuid[16];                          /* UUID */
1541 
1542         void                    *s_fs_info;     /* Filesystem private info */
1543         unsigned int            s_max_links;
1544         fmode_t                 s_mode;
1545 
1546         /* Granularity of c/m/atime in ns.
1547            Cannot be worse than a second */
1548         u32                s_time_gran;
1549 
1550         /*
1551          * The next field is for VFS *only*. No filesystems have any business
1552          * even looking at it. You had been warned.
1553          */
1554         struct mutex s_vfs_rename_mutex;        /* Kludge */
1555 
1556         /*
1557          * Filesystem subtype.  If non-empty the filesystem type field
1558          * in /proc/mounts will be "type.subtype"
1559          */
1560         char *s_subtype;
1561 
1562         /*
1563          * Saved mount options for lazy filesystems using
1564          * generic_show_options()
1565          */
1566         char __rcu *s_options;
1567         const struct dentry_operations *s_d_op; /* default d_op for dentries */
1568 
1569         /*
1570          * Saved pool identifier for cleancache (-1 means none)
1571          */
1572         int cleancache_poolid;
1573 
1574         struct shrinker s_shrink;       /* per-sb shrinker handle */
1575 
1576         /* Number of inodes with nlink == 0 but still referenced */
1577         atomic_long_t s_remove_count;
1578 
1579         /* Being remounted read-only */
1580         int s_readonly_remount;
1581 };
1582 
1583 /* superblock cache pruning functions */
1584 extern void prune_icache_sb(struct super_block *sb, int nr_to_scan);
1585 extern void prune_dcache_sb(struct super_block *sb, int nr_to_scan);
1586 
1587 extern struct timespec current_fs_time(struct super_block *sb);
1588 
1589 /*
1590  * Snapshotting support.
1591  */
1592 
1593 void __sb_end_write(struct super_block *sb, int level);
1594 int __sb_start_write(struct super_block *sb, int level, bool wait);
1595 
1596 /**
1597  * sb_end_write - drop write access to a superblock
1598  * @sb: the super we wrote to
1599  *
1600  * Decrement number of writers to the filesystem. Wake up possible waiters
1601  * wanting to freeze the filesystem.
1602  */
1603 static inline void sb_end_write(struct super_block *sb)
1604 {
1605         __sb_end_write(sb, SB_FREEZE_WRITE);
1606 }
1607 
1608 /**
1609  * sb_end_pagefault - drop write access to a superblock from a page fault
1610  * @sb: the super we wrote to
1611  *
1612  * Decrement number of processes handling write page fault to the filesystem.
1613  * Wake up possible waiters wanting to freeze the filesystem.
1614  */
1615 static inline void sb_end_pagefault(struct super_block *sb)
1616 {
1617         __sb_end_write(sb, SB_FREEZE_PAGEFAULT);
1618 }
1619 
1620 /**
1621  * sb_end_intwrite - drop write access to a superblock for internal fs purposes
1622  * @sb: the super we wrote to
1623  *
1624  * Decrement fs-internal number of writers to the filesystem.  Wake up possible
1625  * waiters wanting to freeze the filesystem.
1626  */
1627 static inline void sb_end_intwrite(struct super_block *sb)
1628 {
1629         __sb_end_write(sb, SB_FREEZE_FS);
1630 }
1631 
1632 /**
1633  * sb_start_write - get write access to a superblock
1634  * @sb: the super we write to
1635  *
1636  * When a process wants to write data or metadata to a file system (i.e. dirty
1637  * a page or an inode), it should embed the operation in a sb_start_write() -
1638  * sb_end_write() pair to get exclusion against file system freezing. This
1639  * function increments number of writers preventing freezing. If the file
1640  * system is already frozen, the function waits until the file system is
1641  * thawed.
1642  *
1643  * Since freeze protection behaves as a lock, users have to preserve
1644  * ordering of freeze protection and other filesystem locks. Generally,
1645  * freeze protection should be the outermost lock. In particular, we have:
1646  *
1647  * sb_start_write
1648  *   -> i_mutex                 (write path, truncate, directory ops, ...)
1649  *   -> s_umount                (freeze_super, thaw_super)
1650  */
1651 static inline void sb_start_write(struct super_block *sb)
1652 {
1653         __sb_start_write(sb, SB_FREEZE_WRITE, true);
1654 }
1655 
1656 static inline int sb_start_write_trylock(struct super_block *sb)
1657 {
1658         return __sb_start_write(sb, SB_FREEZE_WRITE, false);
1659 }
1660 
1661 /**
1662  * sb_start_pagefault - get write access to a superblock from a page fault
1663  * @sb: the super we write to
1664  *
1665  * When a process starts handling write page fault, it should embed the
1666  * operation into sb_start_pagefault() - sb_end_pagefault() pair to get
1667  * exclusion against file system freezing. This is needed since the page fault
1668  * is going to dirty a page. This function increments number of running page
1669  * faults preventing freezing. If the file system is already frozen, the
1670  * function waits until the file system is thawed.
1671  *
1672  * Since page fault freeze protection behaves as a lock, users have to preserve
1673  * ordering of freeze protection and other filesystem locks. It is advised to
1674  * put sb_start_pagefault() close to mmap_sem in lock ordering. Page fault
1675  * handling code implies lock dependency:
1676  *
1677  * mmap_sem
1678  *   -> sb_start_pagefault
1679  */
1680 static inline void sb_start_pagefault(struct super_block *sb)
1681 {
1682         __sb_start_write(sb, SB_FREEZE_PAGEFAULT, true);
1683 }
1684 
1685 /*
1686  * sb_start_intwrite - get write access to a superblock for internal fs purposes
1687  * @sb: the super we write to
1688  *
1689  * This is the third level of protection against filesystem freezing. It is
1690  * free for use by a filesystem. The only requirement is that it must rank
1691  * below sb_start_pagefault.
1692  *
1693  * For example filesystem can call sb_start_intwrite() when starting a
1694  * transaction which somewhat eases handling of freezing for internal sources
1695  * of filesystem changes (internal fs threads, discarding preallocation on file
1696  * close, etc.).
1697  */
1698 static inline void sb_start_intwrite(struct super_block *sb)
1699 {
1700         __sb_start_write(sb, SB_FREEZE_FS, true);
1701 }
1702 
1703 
1704 extern bool inode_owner_or_capable(const struct inode *inode);
1705 
1706 /* not quite ready to be deprecated, but... */
1707 extern void lock_super(struct super_block *);
1708 extern void unlock_super(struct super_block *);
1709 
1710 /*
1711  * VFS helper functions..
1712  */
1713 extern int vfs_create(struct inode *, struct dentry *, umode_t, bool);
1714 extern int vfs_mkdir(struct inode *, struct dentry *, umode_t);
1715 extern int vfs_mknod(struct inode *, struct dentry *, umode_t, dev_t);
1716 extern int vfs_symlink(struct inode *, struct dentry *, const char *);
1717 extern int vfs_link(struct dentry *, struct inode *, struct dentry *);
1718 extern int vfs_rmdir(struct inode *, struct dentry *);
1719 extern int vfs_unlink(struct inode *, struct dentry *);
1720 extern int vfs_rename(struct inode *, struct dentry *, struct inode *, struct dentry *);
1721 
1722 /*
1723  * VFS dentry helper functions.
1724  */
1725 extern void dentry_unhash(struct dentry *dentry);
1726 
1727 /*
1728  * VFS file helper functions.
1729  */
1730 extern void inode_init_owner(struct inode *inode, const struct inode *dir,
1731                         umode_t mode);
1732 /*
1733  * VFS FS_IOC_FIEMAP helper definitions.
1734  */
1735 struct fiemap_extent_info {
1736         unsigned int fi_flags;          /* Flags as passed from user */
1737         unsigned int fi_extents_mapped; /* Number of mapped extents */
1738         unsigned int fi_extents_max;    /* Size of fiemap_extent array */
1739         struct fiemap_extent __user *fi_extents_start; /* Start of
1740                                                         fiemap_extent array */
1741 };
1742 int fiemap_fill_next_extent(struct fiemap_extent_info *info, u64 logical,
1743                             u64 phys, u64 len, u32 flags);
1744 int fiemap_check_flags(struct fiemap_extent_info *fieinfo, u32 fs_flags);
1745 
1746 /*
1747  * File types
1748  *
1749  * NOTE! These match bits 12..15 of stat.st_mode
1750  * (ie "(i_mode >> 12) & 15").
1751  */
1752 #define DT_UNKNOWN      0
1753 #define DT_FIFO         1
1754 #define DT_CHR          2
1755 #define DT_DIR          4
1756 #define DT_BLK          6
1757 #define DT_REG          8
1758 #define DT_LNK          10
1759 #define DT_SOCK         12
1760 #define DT_WHT          14
1761 
1762 /*
1763  * This is the "filldir" function type, used by readdir() to let
1764  * the kernel specify what kind of dirent layout it wants to have.
1765  * This allows the kernel to read directories into kernel space or
1766  * to have different dirent layouts depending on the binary type.
1767  */
1768 typedef int (*filldir_t)(void *, const char *, int, loff_t, u64, unsigned);
1769 struct block_device_operations;
1770 
1771 /* These macros are for out of kernel modules to test that
1772  * the kernel supports the unlocked_ioctl and compat_ioctl
1773  * fields in struct file_operations. */
1774 #define HAVE_COMPAT_IOCTL 1
1775 #define HAVE_UNLOCKED_IOCTL 1
1776 
1777 struct file_operations {
1778         struct module *owner;
1779         loff_t (*llseek) (struct file *, loff_t, int);
1780         ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);
1781         ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
1782         ssize_t (*aio_read) (struct kiocb *, const struct iovec *, unsigned long, loff_t);
1783         ssize_t (*aio_write) (struct kiocb *, const struct iovec *, unsigned long, loff_t);
1784         int (*readdir) (struct file *, void *, filldir_t);
1785         unsigned int (*poll) (struct file *, struct poll_table_struct *);
1786         long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
1787         long (*compat_ioctl) (struct file *, unsigned int, unsigned long);
1788         int (*mmap) (struct file *, struct vm_area_struct *);
1789         int (*open) (struct inode *, struct file *);
1790         int (*flush) (struct file *, fl_owner_t id);
1791         int (*release) (struct inode *, struct file *);
1792         int (*fsync) (struct file *, loff_t, loff_t, int datasync);
1793         int (*aio_fsync) (struct kiocb *, int datasync);
1794         int (*fasync) (int, struct file *, int);
1795         int (*lock) (struct file *, int, struct file_lock *);
1796         ssize_t (*sendpage) (struct file *, struct page *, int, size_t, loff_t *, int);
1797         unsigned long (*get_unmapped_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
1798         int (*check_flags)(int);
1799         int (*flock) (struct file *, int, struct file_lock *);
1800         ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, loff_t *, size_t, unsigned int);
1801         ssize_t (*splice_read)(struct file *, loff_t *, struct pipe_inode_info *, size_t, unsigned int);
1802         int (*setlease)(struct file *, long, struct file_lock **);
1803         long (*fallocate)(struct file *file, int mode, loff_t offset,
1804                           loff_t len);
1805 };
1806 
1807 struct inode_operations {
1808         struct dentry * (*lookup) (struct inode *,struct dentry *, unsigned int);
1809         void * (*follow_link) (struct dentry *, struct nameidata *);
1810         int (*permission) (struct inode *, int);
1811         struct posix_acl * (*get_acl)(struct inode *, int);
1812 
1813         int (*readlink) (struct dentry *, char __user *,int);
1814         void (*put_link) (struct dentry *, struct nameidata *, void *);
1815 
1816         int (*create) (struct inode *,struct dentry *, umode_t, bool);
1817         int (*link) (struct dentry *,struct inode *,struct dentry *);
1818         int (*unlink) (struct inode *,struct dentry *);
1819         int (*symlink) (struct inode *,struct dentry *,const char *);
1820         int (*mkdir) (struct inode *,struct dentry *,umode_t);
1821         int (*rmdir) (struct inode *,struct dentry *);
1822         int (*mknod) (struct inode *,struct dentry *,umode_t,dev_t);
1823         int (*rename) (struct inode *, struct dentry *,
1824                         struct inode *, struct dentry *);
1825         void (*truncate) (struct inode *);
1826         int (*setattr) (struct dentry *, struct iattr *);
1827         int (*getattr) (struct vfsmount *mnt, struct dentry *, struct kstat *);
1828         int (*setxattr) (struct dentry *, const char *,const void *,size_t,int);
1829         ssize_t (*getxattr) (struct dentry *, const char *, void *, size_t);
1830         ssize_t (*listxattr) (struct dentry *, char *, size_t);
1831         int (*removexattr) (struct dentry *, const char *);
1832         int (*fiemap)(struct inode *, struct fiemap_extent_info *, u64 start,
1833                       u64 len);
1834         int (*update_time)(struct inode *, struct timespec *, int);
1835         int (*atomic_open)(struct inode *, struct dentry *,
1836                            struct file *, unsigned open_flag,
1837                            umode_t create_mode, int *opened);
1838 } ____cacheline_aligned;
1839 
1840 struct seq_file;
1841 
1842 ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector,
1843                               unsigned long nr_segs, unsigned long fast_segs,
1844                               struct iovec *fast_pointer,
1845                               struct iovec **ret_pointer);
1846 
1847 extern ssize_t vfs_read(struct file *, char __user *, size_t, loff_t *);
1848 extern ssize_t vfs_write(struct file *, const char __user *, size_t, loff_t *);
1849 extern ssize_t vfs_readv(struct file *, const struct iovec __user *,
1850                 unsigned long, loff_t *);
1851 extern ssize_t vfs_writev(struct file *, const struct iovec __user *,
1852                 unsigned long, loff_t *);
1853 
1854 struct super_operations {
1855         struct inode *(*alloc_inode)(struct super_block *sb);
1856         void (*destroy_inode)(struct inode *);
1857 
1858         void (*dirty_inode) (struct inode *, int flags);
1859         int (*write_inode) (struct inode *, struct writeback_control *wbc);
1860         int (*drop_inode) (struct inode *);
1861         void (*evict_inode) (struct inode *);
1862         void (*put_super) (struct super_block *);
1863         int (*sync_fs)(struct super_block *sb, int wait);
1864         int (*freeze_fs) (struct super_block *);
1865         int (*unfreeze_fs) (struct super_block *);
1866         int (*statfs) (struct dentry *, struct kstatfs *);
1867         int (*remount_fs) (struct super_block *, int *, char *);
1868         void (*umount_begin) (struct super_block *);
1869 
1870         int (*show_options)(struct seq_file *, struct dentry *);
1871         int (*show_devname)(struct seq_file *, struct dentry *);
1872         int (*show_path)(struct seq_file *, struct dentry *);
1873         int (*show_stats)(struct seq_file *, struct dentry *);
1874 #ifdef CONFIG_QUOTA
1875         ssize_t (*quota_read)(struct super_block *, int, char *, size_t, loff_t);
1876         ssize_t (*quota_write)(struct super_block *, int, const char *, size_t, loff_t);
1877 #endif
1878         int (*bdev_try_to_free_page)(struct super_block*, struct page*, gfp_t);
1879         int (*nr_cached_objects)(struct super_block *);
1880         void (*free_cached_objects)(struct super_block *, int);
1881 };
1882 
1883 /*
1884  * Inode state bits.  Protected by inode->i_lock
1885  *
1886  * Three bits determine the dirty state of the inode, I_DIRTY_SYNC,
1887  * I_DIRTY_DATASYNC and I_DIRTY_PAGES.
1888  *
1889  * Four bits define the lifetime of an inode.  Initially, inodes are I_NEW,
1890  * until that flag is cleared.  I_WILL_FREE, I_FREEING and I_CLEAR are set at
1891  * various stages of removing an inode.
1892  *
1893  * Two bits are used for locking and completion notification, I_NEW and I_SYNC.
1894  *
1895  * I_DIRTY_SYNC         Inode is dirty, but doesn't have to be written on
1896  *                      fdatasync().  i_atime is the usual cause.
1897  * I_DIRTY_DATASYNC     Data-related inode changes pending. We keep track of
1898  *                      these changes separately from I_DIRTY_SYNC so that we
1899  *                      don't have to write inode on fdatasync() when only
1900  *                      mtime has changed in it.
1901  * I_DIRTY_PAGES        Inode has dirty pages.  Inode itself may be clean.
1902  * I_NEW                Serves as both a mutex and completion notification.
1903  *                      New inodes set I_NEW.  If two processes both create
1904  *                      the same inode, one of them will release its inode and
1905  *                      wait for I_NEW to be released before returning.
1906  *                      Inodes in I_WILL_FREE, I_FREEING or I_CLEAR state can
1907  *                      also cause waiting on I_NEW, without I_NEW actually
1908  *                      being set.  find_inode() uses this to prevent returning
1909  *                      nearly-dead inodes.
1910  * I_WILL_FREE          Must be set when calling write_inode_now() if i_count
1911  *                      is zero.  I_FREEING must be set when I_WILL_FREE is
1912  *                      cleared.
1913  * I_FREEING            Set when inode is about to be freed but still has dirty
1914  *                      pages or buffers attached or the inode itself is still
1915  *                      dirty.
1916  * I_CLEAR              Added by clear_inode().  In this state the inode is
1917  *                      clean and can be destroyed.  Inode keeps I_FREEING.
1918  *
1919  *                      Inodes that are I_WILL_FREE, I_FREEING or I_CLEAR are
1920  *                      prohibited for many purposes.  iget() must wait for
1921  *                      the inode to be completely released, then create it
1922  *                      anew.  Other functions will just ignore such inodes,
1923  *                      if appropriate.  I_NEW is used for waiting.
1924  *
1925  * I_SYNC               Writeback of inode is running. The bit is set during
1926  *                      data writeback, and cleared with a wakeup on the bit
1927  *                      address once it is done. The bit is also used to pin
1928  *                      the inode in memory for flusher thread.
1929  *
1930  * I_REFERENCED         Marks the inode as recently references on the LRU list.
1931  *
1932  * I_DIO_WAKEUP         Never set.  Only used as a key for wait_on_bit().
1933  *
1934  * Q: What is the difference between I_WILL_FREE and I_FREEING?
1935  */
1936 #define I_DIRTY_SYNC            (1 << 0)
1937 #define I_DIRTY_DATASYNC        (1 << 1)
1938 #define I_DIRTY_PAGES           (1 << 2)
1939 #define __I_NEW                 3
1940 #define I_NEW                   (1 << __I_NEW)
1941 #define I_WILL_FREE             (1 << 4)
1942 #define I_FREEING               (1 << 5)
1943 #define I_CLEAR                 (1 << 6)
1944 #define __I_SYNC                7
1945 #define I_SYNC                  (1 << __I_SYNC)
1946 #define I_REFERENCED            (1 << 8)
1947 #define __I_DIO_WAKEUP          9
1948 #define I_DIO_WAKEUP            (1 << I_DIO_WAKEUP)
1949 
1950 #define I_DIRTY (I_DIRTY_SYNC | I_DIRTY_DATASYNC | I_DIRTY_PAGES)
1951 
1952 extern void __mark_inode_dirty(struct inode *, int);
1953 static inline void mark_inode_dirty(struct inode *inode)
1954 {
1955         __mark_inode_dirty(inode, I_DIRTY);
1956 }
1957 
1958 static inline void mark_inode_dirty_sync(struct inode *inode)
1959 {
1960         __mark_inode_dirty(inode, I_DIRTY_SYNC);
1961 }
1962 
1963 extern void inc_nlink(struct inode *inode);
1964 extern void drop_nlink(struct inode *inode);
1965 extern void clear_nlink(struct inode *inode);
1966 extern void set_nlink(struct inode *inode, unsigned int nlink);
1967 
1968 static inline void inode_inc_link_count(struct inode *inode)
1969 {
1970         inc_nlink(inode);
1971         mark_inode_dirty(inode);
1972 }
1973 
1974 static inline void inode_dec_link_count(struct inode *inode)
1975 {
1976         drop_nlink(inode);
1977         mark_inode_dirty(inode);
1978 }
1979 
1980 /**
1981  * inode_inc_iversion - increments i_version
1982  * @inode: inode that need to be updated
1983  *
1984  * Every time the inode is modified, the i_version field will be incremented.
1985  * The filesystem has to be mounted with i_version flag
1986  */
1987 
1988 static inline void inode_inc_iversion(struct inode *inode)
1989 {
1990        spin_lock(&inode->i_lock);
1991        inode->i_version++;
1992        spin_unlock(&inode->i_lock);
1993 }
1994 
1995 enum file_time_flags {
1996         S_ATIME = 1,
1997         S_MTIME = 2,
1998         S_CTIME = 4,
1999         S_VERSION = 8,
2000 };
2001 
2002 extern void touch_atime(struct path *);
2003 static inline void file_accessed(struct file *file)
2004 {
2005         if (!(file->f_flags & O_NOATIME))
2006                 touch_atime(&file->f_path);
2007 }
2008 
2009 int sync_inode(struct inode *inode, struct writeback_control *wbc);
2010 int sync_inode_metadata(struct inode *inode, int wait);
2011 
2012 struct file_system_type {
2013         const char *name;
2014         int fs_flags;
2015         struct dentry *(*mount) (struct file_system_type *, int,
2016                        const char *, void *);
2017         void (*kill_sb) (struct super_block *);
2018         struct module *owner;
2019         struct file_system_type * next;
2020         struct hlist_head fs_supers;
2021 
2022         struct lock_class_key s_lock_key;
2023         struct lock_class_key s_umount_key;
2024         struct lock_class_key s_vfs_rename_key;
2025         struct lock_class_key s_writers_key[SB_FREEZE_LEVELS];
2026 
2027         struct lock_class_key i_lock_key;
2028         struct lock_class_key i_mutex_key;
2029         struct lock_class_key i_mutex_dir_key;
2030 };
2031 
2032 extern struct dentry *mount_ns(struct file_system_type *fs_type, int flags,
2033         void *data, int (*fill_super)(struct super_block *, void *, int));
2034 extern struct dentry *mount_bdev(struct file_system_type *fs_type,
2035         int flags, const char *dev_name, void *data,
2036         int (*fill_super)(struct super_block *, void *, int));
2037 extern struct dentry *mount_single(struct file_system_type *fs_type,
2038         int flags, void *data,
2039         int (*fill_super)(struct super_block *, void *, int));
2040 extern struct dentry *mount_nodev(struct file_system_type *fs_type,
2041         int flags, void *data,
2042         int (*fill_super)(struct super_block *, void *, int));
2043 extern struct dentry *mount_subtree(struct vfsmount *mnt, const char *path);
2044 void generic_shutdown_super(struct super_block *sb);
2045 void kill_block_super(struct super_block *sb);
2046 void kill_anon_super(struct super_block *sb);
2047 void kill_litter_super(struct super_block *sb);
2048 void deactivate_super(struct super_block *sb);
2049 void deactivate_locked_super(struct super_block *sb);
2050 int set_anon_super(struct super_block *s, void *data);
2051 int get_anon_bdev(dev_t *);
2052 void free_anon_bdev(dev_t);
2053 struct super_block *sget(struct file_system_type *type,
2054                         int (*test)(struct super_block *,void *),
2055                         int (*set)(struct super_block *,void *),
2056                         int flags, void *data);
2057 extern struct dentry *mount_pseudo(struct file_system_type *, char *,
2058         const struct super_operations *ops,
2059         const struct dentry_operations *dops,
2060         unsigned long);
2061 
2062 /* Alas, no aliases. Too much hassle with bringing module.h everywhere */
2063 #define fops_get(fops) \
2064         (((fops) && try_module_get((fops)->owner) ? (fops) : NULL))
2065 #define fops_put(fops) \
2066         do { if (fops) module_put((fops)->owner); } while(0)
2067 
2068 extern int register_filesystem(struct file_system_type *);
2069 extern int unregister_filesystem(struct file_system_type *);
2070 extern struct vfsmount *kern_mount_data(struct file_system_type *, void *data);
2071 #define kern_mount(type) kern_mount_data(type, NULL)
2072 extern void kern_unmount(struct vfsmount *mnt);
2073 extern int may_umount_tree(struct vfsmount *);
2074 extern int may_umount(struct vfsmount *);
2075 extern long do_mount(char *, char *, char *, unsigned long, void *);
2076 extern struct vfsmount *collect_mounts(struct path *);
2077 extern void drop_collected_mounts(struct vfsmount *);
2078 extern int iterate_mounts(int (*)(struct vfsmount *, void *), void *,
2079                           struct vfsmount *);
2080 extern int vfs_statfs(struct path *, struct kstatfs *);
2081 extern int user_statfs(const char __user *, struct kstatfs *);
2082 extern int fd_statfs(int, struct kstatfs *);
2083 extern int vfs_ustat(dev_t, struct kstatfs *);
2084 extern int freeze_super(struct super_block *super);
2085 extern int thaw_super(struct super_block *super);
2086 extern bool our_mnt(struct vfsmount *mnt);
2087 
2088 extern int current_umask(void);
2089 
2090 /* /sys/fs */
2091 extern struct kobject *fs_kobj;
2092 
2093 #define MAX_RW_COUNT (INT_MAX & PAGE_CACHE_MASK)
2094 extern int rw_verify_area(int, struct file *, loff_t *, size_t);
2095 
2096 #define FLOCK_VERIFY_READ  1
2097 #define FLOCK_VERIFY_WRITE 2
2098 
2099 #ifdef CONFIG_FILE_LOCKING
2100 extern int locks_mandatory_locked(struct inode *);
2101 extern int locks_mandatory_area(int, struct inode *, struct file *, loff_t, size_t);
2102 
2103 /*
2104  * Candidates for mandatory locking have the setgid bit set
2105  * but no group execute bit -  an otherwise meaningless combination.
2106  */
2107 
2108 static inline int __mandatory_lock(struct inode *ino)
2109 {
2110         return (ino->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID;
2111 }
2112 
2113 /*
2114  * ... and these candidates should be on MS_MANDLOCK mounted fs,
2115  * otherwise these will be advisory locks
2116  */
2117 
2118 static inline int mandatory_lock(struct inode *ino)
2119 {
2120         return IS_MANDLOCK(ino) && __mandatory_lock(ino);
2121 }
2122 
2123 static inline int locks_verify_locked(struct inode *inode)
2124 {
2125         if (mandatory_lock(inode))
2126                 return locks_mandatory_locked(inode);
2127         return 0;
2128 }
2129 
2130 static inline int locks_verify_truncate(struct inode *inode,
2131                                     struct file *filp,
2132                                     loff_t size)
2133 {
2134         if (inode->i_flock && mandatory_lock(inode))
2135                 return locks_mandatory_area(
2136                         FLOCK_VERIFY_WRITE, inode, filp,
2137                         size < inode->i_size ? size : inode->i_size,
2138                         (size < inode->i_size ? inode->i_size - size
2139                          : size - inode->i_size)
2140                 );
2141         return 0;
2142 }
2143 
2144 static inline int break_lease(struct inode *inode, unsigned int mode)
2145 {
2146         if (inode->i_flock)
2147                 return __break_lease(inode, mode);
2148         return 0;
2149 }
2150 #else /* !CONFIG_FILE_LOCKING */
2151 static inline int locks_mandatory_locked(struct inode *inode)
2152 {
2153         return 0;
2154 }
2155 
2156 static inline int locks_mandatory_area(int rw, struct inode *inode,
2157                                        struct file *filp, loff_t offset,
2158                                        size_t count)
2159 {
2160         return 0;
2161 }
2162 
2163 static inline int __mandatory_lock(struct inode *inode)
2164 {
2165         return 0;
2166 }
2167 
2168 static inline int mandatory_lock(struct inode *inode)
2169 {
2170         return 0;
2171 }
2172 
2173 static inline int locks_verify_locked(struct inode *inode)
2174 {
2175         return 0;
2176 }
2177 
2178 static inline int locks_verify_truncate(struct inode *inode, struct file *filp,
2179                                         size_t size)
2180 {
2181         return 0;
2182 }
2183 
2184 static inline int break_lease(struct inode *inode, unsigned int mode)
2185 {
2186         return 0;
2187 }
2188 
2189 #endif /* CONFIG_FILE_LOCKING */
2190 
2191 /* fs/open.c */
2192 
2193 extern int do_truncate(struct dentry *, loff_t start, unsigned int time_attrs,
2194                        struct file *filp);
2195 extern int do_fallocate(struct file *file, int mode, loff_t offset,
2196                         loff_t len);
2197 extern long do_sys_open(int dfd, const char __user *filename, int flags,
2198                         umode_t mode);
2199 extern struct file *filp_open(const char *, int, umode_t);
2200 extern struct file *file_open_root(struct dentry *, struct vfsmount *,
2201                                    const char *, int);
2202 extern struct file * dentry_open(const struct path *, int, const struct cred *);
2203 extern int filp_close(struct file *, fl_owner_t id);
2204 extern char * getname(const char __user *);
2205 enum {
2206         FILE_CREATED = 1,
2207         FILE_OPENED = 2
2208 };
2209 extern int finish_open(struct file *file, struct dentry *dentry,
2210                         int (*open)(struct inode *, struct file *),
2211                         int *opened);
2212 extern int finish_no_open(struct file *file, struct dentry *dentry);
2213 
2214 /* fs/ioctl.c */
2215 
2216 extern int ioctl_preallocate(struct file *filp, void __user *argp);
2217 
2218 /* fs/dcache.c */
2219 extern void __init vfs_caches_init_early(void);
2220 extern void __init vfs_caches_init(unsigned long);
2221 
2222 extern struct kmem_cache *names_cachep;
2223 
2224 #define __getname_gfp(gfp)      kmem_cache_alloc(names_cachep, (gfp))
2225 #define __getname()             __getname_gfp(GFP_KERNEL)
2226 #define __putname(name)         kmem_cache_free(names_cachep, (void *)(name))
2227 #ifndef CONFIG_AUDITSYSCALL
2228 #define putname(name)   __putname(name)
2229 #else
2230 extern void putname(const char *name);
2231 #endif
2232 
2233 #ifdef CONFIG_BLOCK
2234 extern int register_blkdev(unsigned int, const char *);
2235 extern void unregister_blkdev(unsigned int, const char *);
2236 extern struct block_device *bdget(dev_t);
2237 extern struct block_device *bdgrab(struct block_device *bdev);
2238 extern void bd_set_size(struct block_device *, loff_t size);
2239 extern sector_t blkdev_max_block(struct block_device *bdev);
2240 extern void bd_forget(struct inode *inode);
2241 extern void bdput(struct block_device *);
2242 extern void invalidate_bdev(struct block_device *);
2243 extern void iterate_bdevs(void (*)(struct block_device *, void *), void *);
2244 extern int sync_blockdev(struct block_device *bdev);
2245 extern void kill_bdev(struct block_device *);
2246 extern struct super_block *freeze_bdev(struct block_device *);
2247 extern void emergency_thaw_all(void);
2248 extern int thaw_bdev(struct block_device *bdev, struct super_block *sb);
2249 extern int fsync_bdev(struct block_device *);
2250 #else
2251 static inline void bd_forget(struct inode *inode) {}
2252 static inline int sync_blockdev(struct block_device *bdev) { return 0; }
2253 static inline void kill_bdev(struct block_device *bdev) {}
2254 static inline void invalidate_bdev(struct block_device *bdev) {}
2255 
2256 static inline struct super_block *freeze_bdev(struct block_device *sb)
2257 {
2258         return NULL;
2259 }
2260 
2261 static inline int thaw_bdev(struct block_device *bdev, struct super_block *sb)
2262 {
2263         return 0;
2264 }
2265 
2266 static inline void iterate_bdevs(void (*f)(struct block_device *, void *), void *arg)
2267 {
2268 }
2269 #endif
2270 extern int sync_filesystem(struct super_block *);
2271 extern const struct file_operations def_blk_fops;
2272 extern const struct file_operations def_chr_fops;
2273 extern const struct file_operations bad_sock_fops;
2274 extern const struct file_operations def_fifo_fops;
2275 #ifdef CONFIG_BLOCK
2276 extern int ioctl_by_bdev(struct block_device *, unsigned, unsigned long);
2277 extern int blkdev_ioctl(struct block_device *, fmode_t, unsigned, unsigned long);
2278 extern long compat_blkdev_ioctl(struct file *, unsigned, unsigned long);
2279 extern int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder);
2280 extern struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
2281                                                void *holder);
2282 extern struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode,
2283                                               void *holder);
2284 extern int blkdev_put(struct block_device *bdev, fmode_t mode);
2285 #ifdef CONFIG_SYSFS
2286 extern int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk);
2287 extern void bd_unlink_disk_holder(struct block_device *bdev,
2288                                   struct gendisk *disk);
2289 #else
2290 static inline int bd_link_disk_holder(struct block_device *bdev,
2291                                       struct gendisk *disk)
2292 {
2293         return 0;
2294 }
2295 static inline void bd_unlink_disk_holder(struct block_device *bdev,
2296                                          struct gendisk *disk)
2297 {
2298 }
2299 #endif
2300 #endif
2301 
2302 /* fs/char_dev.c */
2303 #define CHRDEV_MAJOR_HASH_SIZE  255
2304 extern int alloc_chrdev_region(dev_t *, unsigned, unsigned, const char *);
2305 extern int register_chrdev_region(dev_t, unsigned, const char *);
2306 extern int __register_chrdev(unsigned int major, unsigned int baseminor,
2307                              unsigned int count, const char *name,
2308                              const struct file_operations *fops);
2309 extern void __unregister_chrdev(unsigned int major, unsigned int baseminor,
2310                                 unsigned int count, const char *name);
2311 extern void unregister_chrdev_region(dev_t, unsigned);
2312 extern void chrdev_show(struct seq_file *,off_t);
2313 
2314 static inline int register_chrdev(unsigned int major, const char *name,
2315                                   const struct file_operations *fops)
2316 {
2317         return __register_chrdev(major, 0, 256, name, fops);
2318 }
2319 
2320 static inline void unregister_chrdev(unsigned int major, const char *name)
2321 {
2322         __unregister_chrdev(major, 0, 256, name);
2323 }
2324 
2325 /* fs/block_dev.c */
2326 #define BDEVNAME_SIZE   32      /* Largest string for a blockdev identifier */
2327 #define BDEVT_SIZE      10      /* Largest string for MAJ:MIN for blkdev */
2328 
2329 #ifdef CONFIG_BLOCK
2330 #define BLKDEV_MAJOR_HASH_SIZE  255
2331 extern const char *__bdevname(dev_t, char *buffer);
2332 extern const char *bdevname(struct block_device *bdev, char *buffer);
2333 extern struct block_device *lookup_bdev(const char *);
2334 extern void blkdev_show(struct seq_file *,off_t);
2335 
2336 #else
2337 #define BLKDEV_MAJOR_HASH_SIZE  0
2338 #endif
2339 
2340 extern void init_special_inode(struct inode *, umode_t, dev_t);
2341 
2342 /* Invalid inode operations -- fs/bad_inode.c */
2343 extern void make_bad_inode(struct inode *);
2344 extern int is_bad_inode(struct inode *);
2345 
2346 extern const struct file_operations read_pipefifo_fops;
2347 extern const struct file_operations write_pipefifo_fops;
2348 extern const struct file_operations rdwr_pipefifo_fops;
2349 
2350 #ifdef CONFIG_BLOCK
2351 /*
2352  * return READ, READA, or WRITE
2353  */
2354 #define bio_rw(bio)             ((bio)->bi_rw & (RW_MASK | RWA_MASK))
2355 
2356 /*
2357  * return data direction, READ or WRITE
2358  */
2359 #define bio_data_dir(bio)       ((bio)->bi_rw & 1)
2360 
2361 extern void check_disk_size_change(struct gendisk *disk,
2362                                    struct block_device *bdev);
2363 extern int revalidate_disk(struct gendisk *);
2364 extern int check_disk_change(struct block_device *);
2365 extern int __invalidate_device(struct block_device *, bool);
2366 extern int invalidate_partition(struct gendisk *, int);
2367 #endif
2368 unsigned long invalidate_mapping_pages(struct address_space *mapping,
2369                                         pgoff_t start, pgoff_t end);
2370 
2371 static inline void invalidate_remote_inode(struct inode *inode)
2372 {
2373         if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
2374             S_ISLNK(inode->i_mode))
2375                 invalidate_mapping_pages(inode->i_mapping, 0, -1);
2376 }
2377 extern int invalidate_inode_pages2(struct address_space *mapping);
2378 extern int invalidate_inode_pages2_range(struct address_space *mapping,
2379                                          pgoff_t start, pgoff_t end);
2380 extern int write_inode_now(struct inode *, int);
2381 extern int filemap_fdatawrite(struct address_space *);
2382 extern int filemap_flush(struct address_space *);
2383 extern int filemap_fdatawait(struct address_space *);
2384 extern int filemap_fdatawait_range(struct address_space *, loff_t lstart,
2385                                    loff_t lend);
2386 extern int filemap_write_and_wait(struct address_space *mapping);
2387 extern int filemap_write_and_wait_range(struct address_space *mapping,
2388                                         loff_t lstart, loff_t lend);
2389 extern int __filemap_fdatawrite_range(struct address_space *mapping,
2390                                 loff_t start, loff_t end, int sync_mode);
2391 extern int filemap_fdatawrite_range(struct address_space *mapping,
2392                                 loff_t start, loff_t end);
2393 
2394 extern int vfs_fsync_range(struct file *file, loff_t start, loff_t end,
2395                            int datasync);
2396 extern int vfs_fsync(struct file *file, int datasync);
2397 extern int generic_write_sync(struct file *file, loff_t pos, loff_t count);
2398 extern void emergency_sync(void);
2399 extern void emergency_remount(void);
2400 #ifdef CONFIG_BLOCK
2401 extern sector_t bmap(struct inode *, sector_t);
2402 #endif
2403 extern int notify_change(struct dentry *, struct iattr *);
2404 extern int inode_permission(struct inode *, int);
2405 extern int generic_permission(struct inode *, int);
2406 
2407 static inline bool execute_ok(struct inode *inode)
2408 {
2409         return (inode->i_mode & S_IXUGO) || S_ISDIR(inode->i_mode);
2410 }
2411 
2412 /*
2413  * get_write_access() gets write permission for a file.
2414  * put_write_access() releases this write permission.
2415  * This is used for regular files.
2416  * We cannot support write (and maybe mmap read-write shared) accesses and
2417  * MAP_DENYWRITE mmappings simultaneously. The i_writecount field of an inode
2418  * can have the following values:
2419  * 0: no writers, no VM_DENYWRITE mappings
2420  * < 0: (-i_writecount) vm_area_structs with VM_DENYWRITE set exist
2421  * > 0: (i_writecount) users are writing to the file.
2422  *
2423  * Normally we operate on that counter with atomic_{inc,dec} and it's safe
2424  * except for the cases where we don't hold i_writecount yet. Then we need to
2425  * use {get,deny}_write_access() - these functions check the sign and refuse
2426  * to do the change if sign is wrong.
2427  */
2428 static inline int get_write_access(struct inode *inode)
2429 {
2430         return atomic_inc_unless_negative(&inode->i_writecount) ? 0 : -ETXTBSY;
2431 }
2432 static inline int deny_write_access(struct file *file)
2433 {
2434         struct inode *inode = file->f_path.dentry->d_inode;
2435         return atomic_dec_unless_positive(&inode->i_writecount) ? 0 : -ETXTBSY;
2436 }
2437 static inline void put_write_access(struct inode * inode)
2438 {
2439         atomic_dec(&inode->i_writecount);
2440 }
2441 static inline void allow_write_access(struct file *file)
2442 {
2443         if (file)
2444                 atomic_inc(&file->f_path.dentry->d_inode->i_writecount);
2445 }
2446 #ifdef CONFIG_IMA
2447 static inline void i_readcount_dec(struct inode *inode)
2448 {
2449         BUG_ON(!atomic_read(&inode->i_readcount));
2450         atomic_dec(&inode->i_readcount);
2451 }
2452 static inline void i_readcount_inc(struct inode *inode)
2453 {
2454         atomic_inc(&inode->i_readcount);
2455 }
2456 #else
2457 static inline void i_readcount_dec(struct inode *inode)
2458 {
2459         return;
2460 }
2461 static inline void i_readcount_inc(struct inode *inode)
2462 {
2463         return;
2464 }
2465 #endif
2466 extern int do_pipe_flags(int *, int);
2467 
2468 extern int kernel_read(struct file *, loff_t, char *, unsigned long);
2469 extern struct file * open_exec(const char *);
2470  
2471 /* fs/dcache.c -- generic fs support functions */
2472 extern int is_subdir(struct dentry *, struct dentry *);
2473 extern int path_is_under(struct path *, struct path *);
2474 extern ino_t find_inode_number(struct dentry *, struct qstr *);
2475 
2476 #include <linux/err.h>
2477 
2478 /* needed for stackable file system support */
2479 extern loff_t default_llseek(struct file *file, loff_t offset, int origin);
2480 
2481 extern loff_t vfs_llseek(struct file *file, loff_t offset, int origin);
2482 
2483 extern int inode_init_always(struct super_block *, struct inode *);
2484 extern void inode_init_once(struct inode *);
2485 extern void address_space_init_once(struct address_space *mapping);
2486 extern void ihold(struct inode * inode);
2487 extern void iput(struct inode *);
2488 extern struct inode * igrab(struct inode *);
2489 extern ino_t iunique(struct super_block *, ino_t);
2490 extern int inode_needs_sync(struct inode *inode);
2491 extern int generic_delete_inode(struct inode *inode);
2492 static inline int generic_drop_inode(struct inode *inode)
2493 {
2494         return !inode->i_nlink || inode_unhashed(inode);
2495 }
2496 
2497 extern struct inode *ilookup5_nowait(struct super_block *sb,
2498                 unsigned long hashval, int (*test)(struct inode *, void *),
2499                 void *data);
2500 extern struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
2501                 int (*test)(struct inode *, void *), void *data);
2502 extern struct inode *ilookup(struct super_block *sb, unsigned long ino);
2503 
2504 extern struct inode * iget5_locked(struct super_block *, unsigned long, int (*test)(struct inode *, void *), int (*set)(struct inode *, void *), void *);
2505 extern struct inode * iget_locked(struct super_block *, unsigned long);
2506 extern int insert_inode_locked4(struct inode *, unsigned long, int (*test)(struct inode *, void *), void *);
2507 extern int insert_inode_locked(struct inode *);
2508 #ifdef CONFIG_DEBUG_LOCK_ALLOC
2509 extern void lockdep_annotate_inode_mutex_key(struct inode *inode);
2510 #else
2511 static inline void lockdep_annotate_inode_mutex_key(struct inode *inode) { };
2512 #endif
2513 extern void unlock_new_inode(struct inode *);
2514 extern unsigned int get_next_ino(void);
2515 
2516 extern void __iget(struct inode * inode);
2517 extern void iget_failed(struct inode *);
2518 extern void clear_inode(struct inode *);
2519 extern void __destroy_inode(struct inode *);
2520 extern struct inode *new_inode_pseudo(struct super_block *sb);
2521 extern struct inode *new_inode(struct super_block *sb);
2522 extern void free_inode_nonrcu(struct inode *inode);
2523 extern int should_remove_suid(struct dentry *);
2524 extern int file_remove_suid(struct file *);
2525 
2526 extern void __insert_inode_hash(struct inode *, unsigned long hashval);
2527 static inline void insert_inode_hash(struct inode *inode)
2528 {
2529         __insert_inode_hash(inode, inode->i_ino);
2530 }
2531 
2532 extern void __remove_inode_hash(struct inode *);
2533 static inline void remove_inode_hash(struct inode *inode)
2534 {
2535         if (!inode_unhashed(inode))
2536                 __remove_inode_hash(inode);
2537 }
2538 
2539 extern void inode_sb_list_add(struct inode *inode);
2540 
2541 #ifdef CONFIG_BLOCK
2542 extern void submit_bio(int, struct bio *);
2543 extern int bdev_read_only(struct block_device *);
2544 #endif
2545 extern int set_blocksize(struct block_device *, int);
2546 extern int sb_set_blocksize(struct super_block *, int);
2547 extern int sb_min_blocksize(struct super_block *, int);
2548 
2549 extern int generic_file_mmap(struct file *, struct vm_area_struct *);
2550 extern int generic_file_readonly_mmap(struct file *, struct vm_area_struct *);
2551 extern int file_read_actor(read_descriptor_t * desc, struct page *page, unsigned long offset, unsigned long size);
2552 int generic_write_checks(struct file *file, loff_t *pos, size_t *count, int isblk);
2553 extern ssize_t generic_file_aio_read(struct kiocb *, const struct iovec *, unsigned long, loff_t);
2554 extern ssize_t __generic_file_aio_write(struct kiocb *, const struct iovec *, unsigned long,
2555                 loff_t *);
2556 extern ssize_t generic_file_aio_write(struct kiocb *, const struct iovec *, unsigned long, loff_t);
2557 extern ssize_t generic_file_direct_write(struct kiocb *, const struct iovec *,
2558                 unsigned long *, loff_t, loff_t *, size_t, size_t);
2559 extern ssize_t generic_file_buffered_write(struct kiocb *, const struct iovec *,
2560                 unsigned long, loff_t, loff_t *, size_t, ssize_t);
2561 extern ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos);
2562 extern ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos);
2563 extern int generic_segment_checks(const struct iovec *iov,
2564                 unsigned long *nr_segs, size_t *count, int access_flags);
2565 
2566 /* fs/block_dev.c */
2567 extern ssize_t blkdev_aio_write(struct kiocb *iocb, const struct iovec *iov,
2568                                 unsigned long nr_segs, loff_t pos);
2569 extern int blkdev_fsync(struct file *filp, loff_t start, loff_t end,
2570                         int datasync);
2571 extern void block_sync_page(struct page *page);
2572 
2573 /* fs/splice.c */
2574 extern ssize_t generic_file_splice_read(struct file *, loff_t *,
2575                 struct pipe_inode_info *, size_t, unsigned int);
2576 extern ssize_t default_file_splice_read(struct file *, loff_t *,
2577                 struct pipe_inode_info *, size_t, unsigned int);
2578 extern ssize_t generic_file_splice_write(struct pipe_inode_info *,
2579                 struct file *, loff_t *, size_t, unsigned int);
2580 extern ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe,
2581                 struct file *out, loff_t *, size_t len, unsigned int flags);
2582 extern long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
2583                 size_t len, unsigned int flags);
2584 
2585 extern void
2586 file_ra_state_init(struct file_ra_state *ra, struct address_space *mapping);
2587 extern loff_t noop_llseek(struct file *file, loff_t offset, int origin);
2588 extern loff_t no_llseek(struct file *file, loff_t offset, int origin);
2589 extern loff_t generic_file_llseek(struct file *file, loff_t offset, int origin);
2590 extern loff_t generic_file_llseek_size(struct file *file, loff_t offset,
2591                 int origin, loff_t maxsize, loff_t eof);
2592 extern int generic_file_open(struct inode * inode, struct file * filp);
2593 extern int nonseekable_open(struct inode * inode, struct file * filp);
2594 
2595 #ifdef CONFIG_FS_XIP
2596 extern ssize_t xip_file_read(struct file *filp, char __user *buf, size_t len,
2597                              loff_t *ppos);
2598 extern int xip_file_mmap(struct file * file, struct vm_area_struct * vma);
2599 extern ssize_t xip_file_write(struct file *filp, const char __user *buf,
2600                               size_t len, loff_t *ppos);
2601 extern int xip_truncate_page(struct address_space *mapping, loff_t from);
2602 #else
2603 static inline int xip_truncate_page(struct address_space *mapping, loff_t from)
2604 {
2605         return 0;
2606 }
2607 #endif
2608 
2609 #ifdef CONFIG_BLOCK
2610 typedef void (dio_submit_t)(int rw, struct bio *bio, struct inode *inode,
2611                             loff_t file_offset);
2612 
2613 enum {
2614         /* need locking between buffered and direct access */
2615         DIO_LOCKING     = 0x01,
2616 
2617         /* filesystem does not support filling holes */
2618         DIO_SKIP_HOLES  = 0x02,
2619 };
2620 
2621 void dio_end_io(struct bio *bio, int error);
2622 
2623 ssize_t __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
2624         struct block_device *bdev, const struct iovec *iov, loff_t offset,
2625         unsigned long nr_segs, get_block_t get_block, dio_iodone_t end_io,
2626         dio_submit_t submit_io, int flags);
2627 
2628 static inline ssize_t blockdev_direct_IO(int rw, struct kiocb *iocb,
2629                 struct inode *inode, const struct iovec *iov, loff_t offset,
2630                 unsigned long nr_segs, get_block_t get_block)
2631 {
2632         return __blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
2633                                     offset, nr_segs, get_block, NULL, NULL,
2634                                     DIO_LOCKING | DIO_SKIP_HOLES);
2635 }
2636 #endif
2637 
2638 void inode_dio_wait(struct inode *inode);
2639 void inode_dio_done(struct inode *inode);
2640 
2641 extern const struct file_operations generic_ro_fops;
2642 
2643 #define special_file(m) (S_ISCHR(m)||S_ISBLK(m)||S_ISFIFO(m)||S_ISSOCK(m))
2644 
2645 extern int vfs_readlink(struct dentry *, char __user *, int, const char *);
2646 extern int vfs_follow_link(struct nameidata *, const char *);
2647 extern int page_readlink(struct dentry *, char __user *, int);
2648 extern void *page_follow_link_light(struct dentry *, struct nameidata *);
2649 extern void page_put_link(struct dentry *, struct nameidata *, void *);
2650 extern int __page_symlink(struct inode *inode, const char *symname, int len,
2651                 int nofs);
2652 extern int page_symlink(struct inode *inode, const char *symname, int len);
2653 extern const struct inode_operations page_symlink_inode_operations;
2654 extern int generic_readlink(struct dentry *, char __user *, int);
2655 extern void generic_fillattr(struct inode *, struct kstat *);
2656 extern int vfs_getattr(struct vfsmount *, struct dentry *, struct kstat *);
2657 void __inode_add_bytes(struct inode *inode, loff_t bytes);
2658 void inode_add_bytes(struct inode *inode, loff_t bytes);
2659 void inode_sub_bytes(struct inode *inode, loff_t bytes);
2660 loff_t inode_get_bytes(struct inode *inode);
2661 void inode_set_bytes(struct inode *inode, loff_t bytes);
2662 
2663 extern int vfs_readdir(struct file *, filldir_t, void *);
2664 
2665 extern int vfs_stat(const char __user *, struct kstat *);
2666 extern int vfs_lstat(const char __user *, struct kstat *);
2667 extern int vfs_fstat(unsigned int, struct kstat *);
2668 extern int vfs_fstatat(int , const char __user *, struct kstat *, int);
2669 
2670 extern int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd,
2671                     unsigned long arg);
2672 extern int __generic_block_fiemap(struct inode *inode,
2673                                   struct fiemap_extent_info *fieinfo,
2674                                   loff_t start, loff_t len,
2675                                   get_block_t *get_block);
2676 extern int generic_block_fiemap(struct inode *inode,
2677                                 struct fiemap_extent_info *fieinfo, u64 start,
2678                                 u64 len, get_block_t *get_block);
2679 
2680 extern void get_filesystem(struct file_system_type *fs);
2681 extern void put_filesystem(struct file_system_type *fs);
2682 extern struct file_system_type *get_fs_type(const char *name);
2683 extern struct super_block *get_super(struct block_device *);
2684 extern struct super_block *get_super_thawed(struct block_device *);
2685 extern struct super_block *get_active_super(struct block_device *bdev);
2686 extern void drop_super(struct super_block *sb);
2687 extern void iterate_supers(void (*)(struct super_block *, void *), void *);
2688 extern void iterate_supers_type(struct file_system_type *,
2689                                 void (*)(struct super_block *, void *), void *);
2690 
2691 extern int dcache_dir_open(struct inode *, struct file *);
2692 extern int dcache_dir_close(struct inode *, struct file *);
2693 extern loff_t dcache_dir_lseek(struct file *, loff_t, int);
2694 extern int dcache_readdir(struct file *, void *, filldir_t);
2695 extern int simple_setattr(struct dentry *, struct iattr *);
2696 extern int simple_getattr(struct vfsmount *, struct dentry *, struct kstat *);
2697 extern int simple_statfs(struct dentry *, struct kstatfs *);
2698 extern int simple_open(struct inode *inode, struct file *file);
2699 extern int simple_link(struct dentry *, struct inode *, struct dentry *);
2700 extern int simple_unlink(struct inode *, struct dentry *);
2701 extern int simple_rmdir(struct inode *, struct dentry *);
2702 extern int simple_rename(struct inode *, struct dentry *, struct inode *, struct dentry *);
2703 extern int noop_fsync(struct file *, loff_t, loff_t, int);
2704 extern int simple_empty(struct dentry *);
2705 extern int simple_readpage(struct file *file, struct page *page);
2706 extern int simple_write_begin(struct file *file, struct address_space *mapping,
2707                         loff_t pos, unsigned len, unsigned flags,
2708                         struct page **pagep, void **fsdata);
2709 extern int simple_write_end(struct file *file, struct address_space *mapping,
2710                         loff_t pos, unsigned len, unsigned copied,
2711                         struct page *page, void *fsdata);
2712 
2713 extern struct dentry *simple_lookup(struct inode *, struct dentry *, unsigned int flags);
2714 extern ssize_t generic_read_dir(struct file *, char __user *, size_t, loff_t *);
2715 extern const struct file_operations simple_dir_operations;
2716 extern const struct inode_operations simple_dir_inode_operations;
2717 struct tree_descr { char *name; const struct file_operations *ops; int mode; };
2718 struct dentry *d_alloc_name(struct dentry *, const char *);
2719 extern int simple_fill_super(struct super_block *, unsigned long, struct tree_descr *);
2720 extern int simple_pin_fs(struct file_system_type *, struct vfsmount **mount, int *count);
2721 extern void simple_release_fs(struct vfsmount **mount, int *count);
2722 
2723 extern ssize_t simple_read_from_buffer(void __user *to, size_t count,
2724                         loff_t *ppos, const void *from, size_t available);
2725 extern ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos,
2726                 const void __user *from, size_t count);
2727 
2728 extern int generic_file_fsync(struct file *, loff_t, loff_t, int);
2729 
2730 extern int generic_check_addressable(unsigned, u64);
2731 
2732 #ifdef CONFIG_MIGRATION
2733 extern int buffer_migrate_page(struct address_space *,
2734                                 struct page *, struct page *,
2735                                 enum migrate_mode);
2736 #else
2737 #define buffer_migrate_page NULL
2738 #endif
2739 
2740 extern int inode_change_ok(const struct inode *, struct iattr *);
2741 extern int inode_newsize_ok(const struct inode *, loff_t offset);
2742 extern void setattr_copy(struct inode *inode, const struct iattr *attr);
2743 
2744 extern int file_update_time(struct file *file);
2745 
2746 extern int generic_show_options(struct seq_file *m, struct dentry *root);
2747 extern void save_mount_options(struct super_block *sb, char *options);
2748 extern void replace_mount_options(struct super_block *sb, char *options);
2749 
2750 static inline ino_t parent_ino(struct dentry *dentry)
2751 {
2752         ino_t res;
2753 
2754         /*
2755          * Don't strictly need d_lock here? If the parent ino could change
2756          * then surely we'd have a deeper race in the caller?
2757          */
2758         spin_lock(&dentry->d_lock);
2759         res = dentry->d_parent->d_inode->i_ino;
2760         spin_unlock(&dentry->d_lock);
2761         return res;
2762 }
2763 
2764 /* Transaction based IO helpers */
2765 
2766 /*
2767  * An argresp is stored in an allocated page and holds the
2768  * size of the argument or response, along with its content
2769  */
2770 struct simple_transaction_argresp {
2771         ssize_t size;
2772         char data[0];
2773 };
2774 
2775 #define SIMPLE_TRANSACTION_LIMIT (PAGE_SIZE - sizeof(struct simple_transaction_argresp))
2776 
2777 char *simple_transaction_get(struct file *file, const char __user *buf,
2778                                 size_t size);
2779 ssize_t simple_transaction_read(struct file *file, char __user *buf,
2780                                 size_t size, loff_t *pos);
2781 int simple_transaction_release(struct inode *inode, struct file *file);
2782 
2783 void simple_transaction_set(struct file *file, size_t n);
2784 
2785 /*
2786  * simple attribute files
2787  *
2788  * These attributes behave similar to those in sysfs:
2789  *
2790  * Writing to an attribute immediately sets a value, an open file can be
2791  * written to multiple times.
2792  *
2793  * Reading from an attribute creates a buffer from the value that might get
2794  * read with multiple read calls. When the attribute has been read
2795  * completely, no further read calls are possible until the file is opened
2796  * again.
2797  *
2798  * All attributes contain a text representation of a numeric value
2799  * that are accessed with the get() and set() functions.
2800  */
2801 #define DEFINE_SIMPLE_ATTRIBUTE(__fops, __get, __set, __fmt)            \
2802 static int __fops ## _open(struct inode *inode, struct file *file)      \
2803 {                                                                       \
2804         __simple_attr_check_format(__fmt, 0ull);                        \
2805         return simple_attr_open(inode, file, __get, __set, __fmt);      \
2806 }                                                                       \
2807 static const struct file_operations __fops = {                          \
2808         .owner   = THIS_MODULE,                                         \
2809         .open    = __fops ## _open,                                     \
2810         .release = simple_attr_release,                                 \
2811         .read    = simple_attr_read,                                    \
2812         .write   = simple_attr_write,                                   \
2813         .llseek  = generic_file_llseek,                                 \
2814 };
2815 
2816 static inline __printf(1, 2)
2817 void __simple_attr_check_format(const char *fmt, ...)
2818 {
2819         /* don't do anything, just let the compiler check the arguments; */
2820 }
2821 
2822 int simple_attr_open(struct inode *inode, struct file *file,
2823                      int (*get)(void *, u64 *), int (*set)(void *, u64),
2824                      const char *fmt);
2825 int simple_attr_release(struct inode *inode, struct file *file);
2826 ssize_t simple_attr_read(struct file *file, char __user *buf,
2827                          size_t len, loff_t *ppos);
2828 ssize_t simple_attr_write(struct file *file, const char __user *buf,
2829                           size_t len, loff_t *ppos);
2830 
2831 struct ctl_table;
2832 int proc_nr_files(struct ctl_table *table, int write,
2833                   void __user *buffer, size_t *lenp, loff_t *ppos);
2834 int proc_nr_dentry(struct ctl_table *table, int write,
2835                   void __user *buffer, size_t *lenp, loff_t *ppos);
2836 int proc_nr_inodes(struct ctl_table *table, int write,
2837                    void __user *buffer, size_t *lenp, loff_t *ppos);
2838 int __init get_filesystem_list(char *buf);
2839 
2840 #define __FMODE_EXEC            ((__force int) FMODE_EXEC)
2841 #define __FMODE_NONOTIFY        ((__force int) FMODE_NONOTIFY)
2842 
2843 #define ACC_MODE(x) ("\004\002\006\006"[(x)&O_ACCMODE])
2844 #define OPEN_FMODE(flag) ((__force fmode_t)(((flag + 1) & O_ACCMODE) | \
2845                                             (flag & __FMODE_NONOTIFY)))
2846 
2847 static inline int is_sxid(umode_t mode)
2848 {
2849         return (mode & S_ISUID) || ((mode & S_ISGID) && (mode & S_IXGRP));
2850 }
2851 
2852 static inline void inode_has_no_xattr(struct inode *inode)
2853 {
2854         if (!is_sxid(inode->i_mode) && (inode->i_sb->s_flags & MS_NOSEC))
2855                 inode->i_flags |= S_NOSEC;
2856 }
2857 
2858 #endif /* __KERNEL__ */
2859 #endif /* _LINUX_FS_H */
2860 

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