Version:  2.0.40 2.2.26 2.4.37 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19

Linux/include/linux/fs.h

  1 #ifndef _LINUX_FS_H
  2 #define _LINUX_FS_H
  3 
  4 
  5 #include <linux/linkage.h>
  6 #include <linux/wait.h>
  7 #include <linux/kdev_t.h>
  8 #include <linux/dcache.h>
  9 #include <linux/path.h>
 10 #include <linux/stat.h>
 11 #include <linux/cache.h>
 12 #include <linux/list.h>
 13 #include <linux/list_lru.h>
 14 #include <linux/llist.h>
 15 #include <linux/radix-tree.h>
 16 #include <linux/rbtree.h>
 17 #include <linux/init.h>
 18 #include <linux/pid.h>
 19 #include <linux/bug.h>
 20 #include <linux/mutex.h>
 21 #include <linux/rwsem.h>
 22 #include <linux/capability.h>
 23 #include <linux/semaphore.h>
 24 #include <linux/fiemap.h>
 25 #include <linux/rculist_bl.h>
 26 #include <linux/atomic.h>
 27 #include <linux/shrinker.h>
 28 #include <linux/migrate_mode.h>
 29 #include <linux/uidgid.h>
 30 #include <linux/lockdep.h>
 31 #include <linux/percpu-rwsem.h>
 32 #include <linux/blk_types.h>
 33 
 34 #include <asm/byteorder.h>
 35 #include <uapi/linux/fs.h>
 36 
 37 struct export_operations;
 38 struct hd_geometry;
 39 struct iovec;
 40 struct nameidata;
 41 struct kiocb;
 42 struct kobject;
 43 struct pipe_inode_info;
 44 struct poll_table_struct;
 45 struct kstatfs;
 46 struct vm_area_struct;
 47 struct vfsmount;
 48 struct cred;
 49 struct swap_info_struct;
 50 struct seq_file;
 51 struct workqueue_struct;
 52 struct iov_iter;
 53 
 54 extern void __init inode_init(void);
 55 extern void __init inode_init_early(void);
 56 extern void __init files_init(unsigned long);
 57 
 58 extern struct files_stat_struct files_stat;
 59 extern unsigned long get_max_files(void);
 60 extern int sysctl_nr_open;
 61 extern struct inodes_stat_t inodes_stat;
 62 extern int leases_enable, lease_break_time;
 63 extern int sysctl_protected_symlinks;
 64 extern int sysctl_protected_hardlinks;
 65 
 66 struct buffer_head;
 67 typedef int (get_block_t)(struct inode *inode, sector_t iblock,
 68                         struct buffer_head *bh_result, int create);
 69 typedef void (dio_iodone_t)(struct kiocb *iocb, loff_t offset,
 70                         ssize_t bytes, void *private);
 71 
 72 #define MAY_EXEC                0x00000001
 73 #define MAY_WRITE               0x00000002
 74 #define MAY_READ                0x00000004
 75 #define MAY_APPEND              0x00000008
 76 #define MAY_ACCESS              0x00000010
 77 #define MAY_OPEN                0x00000020
 78 #define MAY_CHDIR               0x00000040
 79 /* called from RCU mode, don't block */
 80 #define MAY_NOT_BLOCK           0x00000080
 81 
 82 /*
 83  * flags in file.f_mode.  Note that FMODE_READ and FMODE_WRITE must correspond
 84  * to O_WRONLY and O_RDWR via the strange trick in __dentry_open()
 85  */
 86 
 87 /* file is open for reading */
 88 #define FMODE_READ              ((__force fmode_t)0x1)
 89 /* file is open for writing */
 90 #define FMODE_WRITE             ((__force fmode_t)0x2)
 91 /* file is seekable */
 92 #define FMODE_LSEEK             ((__force fmode_t)0x4)
 93 /* file can be accessed using pread */
 94 #define FMODE_PREAD             ((__force fmode_t)0x8)
 95 /* file can be accessed using pwrite */
 96 #define FMODE_PWRITE            ((__force fmode_t)0x10)
 97 /* File is opened for execution with sys_execve / sys_uselib */
 98 #define FMODE_EXEC              ((__force fmode_t)0x20)
 99 /* File is opened with O_NDELAY (only set for block devices) */
100 #define FMODE_NDELAY            ((__force fmode_t)0x40)
101 /* File is opened with O_EXCL (only set for block devices) */
102 #define FMODE_EXCL              ((__force fmode_t)0x80)
103 /* File is opened using open(.., 3, ..) and is writeable only for ioctls
104    (specialy hack for floppy.c) */
105 #define FMODE_WRITE_IOCTL       ((__force fmode_t)0x100)
106 /* 32bit hashes as llseek() offset (for directories) */
107 #define FMODE_32BITHASH         ((__force fmode_t)0x200)
108 /* 64bit hashes as llseek() offset (for directories) */
109 #define FMODE_64BITHASH         ((__force fmode_t)0x400)
110 
111 /*
112  * Don't update ctime and mtime.
113  *
114  * Currently a special hack for the XFS open_by_handle ioctl, but we'll
115  * hopefully graduate it to a proper O_CMTIME flag supported by open(2) soon.
116  */
117 #define FMODE_NOCMTIME          ((__force fmode_t)0x800)
118 
119 /* Expect random access pattern */
120 #define FMODE_RANDOM            ((__force fmode_t)0x1000)
121 
122 /* File is huge (eg. /dev/kmem): treat loff_t as unsigned */
123 #define FMODE_UNSIGNED_OFFSET   ((__force fmode_t)0x2000)
124 
125 /* File is opened with O_PATH; almost nothing can be done with it */
126 #define FMODE_PATH              ((__force fmode_t)0x4000)
127 
128 /* File needs atomic accesses to f_pos */
129 #define FMODE_ATOMIC_POS        ((__force fmode_t)0x8000)
130 /* Write access to underlying fs */
131 #define FMODE_WRITER            ((__force fmode_t)0x10000)
132 /* Has read method(s) */
133 #define FMODE_CAN_READ          ((__force fmode_t)0x20000)
134 /* Has write method(s) */
135 #define FMODE_CAN_WRITE         ((__force fmode_t)0x40000)
136 
137 /* File was opened by fanotify and shouldn't generate fanotify events */
138 #define FMODE_NONOTIFY          ((__force fmode_t)0x4000000)
139 
140 /*
141  * Flag for rw_copy_check_uvector and compat_rw_copy_check_uvector
142  * that indicates that they should check the contents of the iovec are
143  * valid, but not check the memory that the iovec elements
144  * points too.
145  */
146 #define CHECK_IOVEC_ONLY -1
147 
148 /*
149  * The below are the various read and write types that we support. Some of
150  * them include behavioral modifiers that send information down to the
151  * block layer and IO scheduler. Terminology:
152  *
153  *      The block layer uses device plugging to defer IO a little bit, in
154  *      the hope that we will see more IO very shortly. This increases
155  *      coalescing of adjacent IO and thus reduces the number of IOs we
156  *      have to send to the device. It also allows for better queuing,
157  *      if the IO isn't mergeable. If the caller is going to be waiting
158  *      for the IO, then he must ensure that the device is unplugged so
159  *      that the IO is dispatched to the driver.
160  *
161  *      All IO is handled async in Linux. This is fine for background
162  *      writes, but for reads or writes that someone waits for completion
163  *      on, we want to notify the block layer and IO scheduler so that they
164  *      know about it. That allows them to make better scheduling
165  *      decisions. So when the below references 'sync' and 'async', it
166  *      is referencing this priority hint.
167  *
168  * With that in mind, the available types are:
169  *
170  * READ                 A normal read operation. Device will be plugged.
171  * READ_SYNC            A synchronous read. Device is not plugged, caller can
172  *                      immediately wait on this read without caring about
173  *                      unplugging.
174  * READA                Used for read-ahead operations. Lower priority, and the
175  *                      block layer could (in theory) choose to ignore this
176  *                      request if it runs into resource problems.
177  * WRITE                A normal async write. Device will be plugged.
178  * WRITE_SYNC           Synchronous write. Identical to WRITE, but passes down
179  *                      the hint that someone will be waiting on this IO
180  *                      shortly. The write equivalent of READ_SYNC.
181  * WRITE_ODIRECT        Special case write for O_DIRECT only.
182  * WRITE_FLUSH          Like WRITE_SYNC but with preceding cache flush.
183  * WRITE_FUA            Like WRITE_SYNC but data is guaranteed to be on
184  *                      non-volatile media on completion.
185  * WRITE_FLUSH_FUA      Combination of WRITE_FLUSH and FUA. The IO is preceded
186  *                      by a cache flush and data is guaranteed to be on
187  *                      non-volatile media on completion.
188  *
189  */
190 #define RW_MASK                 REQ_WRITE
191 #define RWA_MASK                REQ_RAHEAD
192 
193 #define READ                    0
194 #define WRITE                   RW_MASK
195 #define READA                   RWA_MASK
196 
197 #define READ_SYNC               (READ | REQ_SYNC)
198 #define WRITE_SYNC              (WRITE | REQ_SYNC | REQ_NOIDLE)
199 #define WRITE_ODIRECT           (WRITE | REQ_SYNC)
200 #define WRITE_FLUSH             (WRITE | REQ_SYNC | REQ_NOIDLE | REQ_FLUSH)
201 #define WRITE_FUA               (WRITE | REQ_SYNC | REQ_NOIDLE | REQ_FUA)
202 #define WRITE_FLUSH_FUA         (WRITE | REQ_SYNC | REQ_NOIDLE | REQ_FLUSH | REQ_FUA)
203 
204 /*
205  * Attribute flags.  These should be or-ed together to figure out what
206  * has been changed!
207  */
208 #define ATTR_MODE       (1 << 0)
209 #define ATTR_UID        (1 << 1)
210 #define ATTR_GID        (1 << 2)
211 #define ATTR_SIZE       (1 << 3)
212 #define ATTR_ATIME      (1 << 4)
213 #define ATTR_MTIME      (1 << 5)
214 #define ATTR_CTIME      (1 << 6)
215 #define ATTR_ATIME_SET  (1 << 7)
216 #define ATTR_MTIME_SET  (1 << 8)
217 #define ATTR_FORCE      (1 << 9) /* Not a change, but a change it */
218 #define ATTR_ATTR_FLAG  (1 << 10)
219 #define ATTR_KILL_SUID  (1 << 11)
220 #define ATTR_KILL_SGID  (1 << 12)
221 #define ATTR_FILE       (1 << 13)
222 #define ATTR_KILL_PRIV  (1 << 14)
223 #define ATTR_OPEN       (1 << 15) /* Truncating from open(O_TRUNC) */
224 #define ATTR_TIMES_SET  (1 << 16)
225 
226 /*
227  * Whiteout is represented by a char device.  The following constants define the
228  * mode and device number to use.
229  */
230 #define WHITEOUT_MODE 0
231 #define WHITEOUT_DEV 0
232 
233 /*
234  * This is the Inode Attributes structure, used for notify_change().  It
235  * uses the above definitions as flags, to know which values have changed.
236  * Also, in this manner, a Filesystem can look at only the values it cares
237  * about.  Basically, these are the attributes that the VFS layer can
238  * request to change from the FS layer.
239  *
240  * Derek Atkins <warlord@MIT.EDU> 94-10-20
241  */
242 struct iattr {
243         unsigned int    ia_valid;
244         umode_t         ia_mode;
245         kuid_t          ia_uid;
246         kgid_t          ia_gid;
247         loff_t          ia_size;
248         struct timespec ia_atime;
249         struct timespec ia_mtime;
250         struct timespec ia_ctime;
251 
252         /*
253          * Not an attribute, but an auxiliary info for filesystems wanting to
254          * implement an ftruncate() like method.  NOTE: filesystem should
255          * check for (ia_valid & ATTR_FILE), and not for (ia_file != NULL).
256          */
257         struct file     *ia_file;
258 };
259 
260 /*
261  * Includes for diskquotas.
262  */
263 #include <linux/quota.h>
264 
265 /*
266  * Maximum number of layers of fs stack.  Needs to be limited to
267  * prevent kernel stack overflow
268  */
269 #define FILESYSTEM_MAX_STACK_DEPTH 2
270 
271 /** 
272  * enum positive_aop_returns - aop return codes with specific semantics
273  *
274  * @AOP_WRITEPAGE_ACTIVATE: Informs the caller that page writeback has
275  *                          completed, that the page is still locked, and
276  *                          should be considered active.  The VM uses this hint
277  *                          to return the page to the active list -- it won't
278  *                          be a candidate for writeback again in the near
279  *                          future.  Other callers must be careful to unlock
280  *                          the page if they get this return.  Returned by
281  *                          writepage(); 
282  *
283  * @AOP_TRUNCATED_PAGE: The AOP method that was handed a locked page has
284  *                      unlocked it and the page might have been truncated.
285  *                      The caller should back up to acquiring a new page and
286  *                      trying again.  The aop will be taking reasonable
287  *                      precautions not to livelock.  If the caller held a page
288  *                      reference, it should drop it before retrying.  Returned
289  *                      by readpage().
290  *
291  * address_space_operation functions return these large constants to indicate
292  * special semantics to the caller.  These are much larger than the bytes in a
293  * page to allow for functions that return the number of bytes operated on in a
294  * given page.
295  */
296 
297 enum positive_aop_returns {
298         AOP_WRITEPAGE_ACTIVATE  = 0x80000,
299         AOP_TRUNCATED_PAGE      = 0x80001,
300 };
301 
302 #define AOP_FLAG_UNINTERRUPTIBLE        0x0001 /* will not do a short write */
303 #define AOP_FLAG_CONT_EXPAND            0x0002 /* called from cont_expand */
304 #define AOP_FLAG_NOFS                   0x0004 /* used by filesystem to direct
305                                                 * helper code (eg buffer layer)
306                                                 * to clear GFP_FS from alloc */
307 
308 /*
309  * oh the beauties of C type declarations.
310  */
311 struct page;
312 struct address_space;
313 struct writeback_control;
314 
315 /*
316  * "descriptor" for what we're up to with a read.
317  * This allows us to use the same read code yet
318  * have multiple different users of the data that
319  * we read from a file.
320  *
321  * The simplest case just copies the data to user
322  * mode.
323  */
324 typedef struct {
325         size_t written;
326         size_t count;
327         union {
328                 char __user *buf;
329                 void *data;
330         } arg;
331         int error;
332 } read_descriptor_t;
333 
334 typedef int (*read_actor_t)(read_descriptor_t *, struct page *,
335                 unsigned long, unsigned long);
336 
337 struct address_space_operations {
338         int (*writepage)(struct page *page, struct writeback_control *wbc);
339         int (*readpage)(struct file *, struct page *);
340 
341         /* Write back some dirty pages from this mapping. */
342         int (*writepages)(struct address_space *, struct writeback_control *);
343 
344         /* Set a page dirty.  Return true if this dirtied it */
345         int (*set_page_dirty)(struct page *page);
346 
347         int (*readpages)(struct file *filp, struct address_space *mapping,
348                         struct list_head *pages, unsigned nr_pages);
349 
350         int (*write_begin)(struct file *, struct address_space *mapping,
351                                 loff_t pos, unsigned len, unsigned flags,
352                                 struct page **pagep, void **fsdata);
353         int (*write_end)(struct file *, struct address_space *mapping,
354                                 loff_t pos, unsigned len, unsigned copied,
355                                 struct page *page, void *fsdata);
356 
357         /* Unfortunately this kludge is needed for FIBMAP. Don't use it */
358         sector_t (*bmap)(struct address_space *, sector_t);
359         void (*invalidatepage) (struct page *, unsigned int, unsigned int);
360         int (*releasepage) (struct page *, gfp_t);
361         void (*freepage)(struct page *);
362         ssize_t (*direct_IO)(int, struct kiocb *, struct iov_iter *iter, loff_t offset);
363         int (*get_xip_mem)(struct address_space *, pgoff_t, int,
364                                                 void **, unsigned long *);
365         /*
366          * migrate the contents of a page to the specified target. If
367          * migrate_mode is MIGRATE_ASYNC, it must not block.
368          */
369         int (*migratepage) (struct address_space *,
370                         struct page *, struct page *, enum migrate_mode);
371         int (*launder_page) (struct page *);
372         int (*is_partially_uptodate) (struct page *, unsigned long,
373                                         unsigned long);
374         void (*is_dirty_writeback) (struct page *, bool *, bool *);
375         int (*error_remove_page)(struct address_space *, struct page *);
376 
377         /* swapfile support */
378         int (*swap_activate)(struct swap_info_struct *sis, struct file *file,
379                                 sector_t *span);
380         void (*swap_deactivate)(struct file *file);
381 };
382 
383 extern const struct address_space_operations empty_aops;
384 
385 /*
386  * pagecache_write_begin/pagecache_write_end must be used by general code
387  * to write into the pagecache.
388  */
389 int pagecache_write_begin(struct file *, struct address_space *mapping,
390                                 loff_t pos, unsigned len, unsigned flags,
391                                 struct page **pagep, void **fsdata);
392 
393 int pagecache_write_end(struct file *, struct address_space *mapping,
394                                 loff_t pos, unsigned len, unsigned copied,
395                                 struct page *page, void *fsdata);
396 
397 struct backing_dev_info;
398 struct address_space {
399         struct inode            *host;          /* owner: inode, block_device */
400         struct radix_tree_root  page_tree;      /* radix tree of all pages */
401         spinlock_t              tree_lock;      /* and lock protecting it */
402         atomic_t                i_mmap_writable;/* count VM_SHARED mappings */
403         struct rb_root          i_mmap;         /* tree of private and shared mappings */
404         struct list_head        i_mmap_nonlinear;/*list VM_NONLINEAR mappings */
405         struct rw_semaphore     i_mmap_rwsem;   /* protect tree, count, list */
406         /* Protected by tree_lock together with the radix tree */
407         unsigned long           nrpages;        /* number of total pages */
408         unsigned long           nrshadows;      /* number of shadow entries */
409         pgoff_t                 writeback_index;/* writeback starts here */
410         const struct address_space_operations *a_ops;   /* methods */
411         unsigned long           flags;          /* error bits/gfp mask */
412         struct backing_dev_info *backing_dev_info; /* device readahead, etc */
413         spinlock_t              private_lock;   /* for use by the address_space */
414         struct list_head        private_list;   /* ditto */
415         void                    *private_data;  /* ditto */
416 } __attribute__((aligned(sizeof(long))));
417         /*
418          * On most architectures that alignment is already the case; but
419          * must be enforced here for CRIS, to let the least significant bit
420          * of struct page's "mapping" pointer be used for PAGE_MAPPING_ANON.
421          */
422 struct request_queue;
423 
424 struct block_device {
425         dev_t                   bd_dev;  /* not a kdev_t - it's a search key */
426         int                     bd_openers;
427         struct inode *          bd_inode;       /* will die */
428         struct super_block *    bd_super;
429         struct mutex            bd_mutex;       /* open/close mutex */
430         struct list_head        bd_inodes;
431         void *                  bd_claiming;
432         void *                  bd_holder;
433         int                     bd_holders;
434         bool                    bd_write_holder;
435 #ifdef CONFIG_SYSFS
436         struct list_head        bd_holder_disks;
437 #endif
438         struct block_device *   bd_contains;
439         unsigned                bd_block_size;
440         struct hd_struct *      bd_part;
441         /* number of times partitions within this device have been opened. */
442         unsigned                bd_part_count;
443         int                     bd_invalidated;
444         struct gendisk *        bd_disk;
445         struct request_queue *  bd_queue;
446         struct list_head        bd_list;
447         /*
448          * Private data.  You must have bd_claim'ed the block_device
449          * to use this.  NOTE:  bd_claim allows an owner to claim
450          * the same device multiple times, the owner must take special
451          * care to not mess up bd_private for that case.
452          */
453         unsigned long           bd_private;
454 
455         /* The counter of freeze processes */
456         int                     bd_fsfreeze_count;
457         /* Mutex for freeze */
458         struct mutex            bd_fsfreeze_mutex;
459 };
460 
461 /*
462  * Radix-tree tags, for tagging dirty and writeback pages within the pagecache
463  * radix trees
464  */
465 #define PAGECACHE_TAG_DIRTY     0
466 #define PAGECACHE_TAG_WRITEBACK 1
467 #define PAGECACHE_TAG_TOWRITE   2
468 
469 int mapping_tagged(struct address_space *mapping, int tag);
470 
471 static inline void i_mmap_lock_write(struct address_space *mapping)
472 {
473         down_write(&mapping->i_mmap_rwsem);
474 }
475 
476 static inline void i_mmap_unlock_write(struct address_space *mapping)
477 {
478         up_write(&mapping->i_mmap_rwsem);
479 }
480 
481 static inline void i_mmap_lock_read(struct address_space *mapping)
482 {
483         down_read(&mapping->i_mmap_rwsem);
484 }
485 
486 static inline void i_mmap_unlock_read(struct address_space *mapping)
487 {
488         up_read(&mapping->i_mmap_rwsem);
489 }
490 
491 /*
492  * Might pages of this file be mapped into userspace?
493  */
494 static inline int mapping_mapped(struct address_space *mapping)
495 {
496         return  !RB_EMPTY_ROOT(&mapping->i_mmap) ||
497                 !list_empty(&mapping->i_mmap_nonlinear);
498 }
499 
500 /*
501  * Might pages of this file have been modified in userspace?
502  * Note that i_mmap_writable counts all VM_SHARED vmas: do_mmap_pgoff
503  * marks vma as VM_SHARED if it is shared, and the file was opened for
504  * writing i.e. vma may be mprotected writable even if now readonly.
505  *
506  * If i_mmap_writable is negative, no new writable mappings are allowed. You
507  * can only deny writable mappings, if none exists right now.
508  */
509 static inline int mapping_writably_mapped(struct address_space *mapping)
510 {
511         return atomic_read(&mapping->i_mmap_writable) > 0;
512 }
513 
514 static inline int mapping_map_writable(struct address_space *mapping)
515 {
516         return atomic_inc_unless_negative(&mapping->i_mmap_writable) ?
517                 0 : -EPERM;
518 }
519 
520 static inline void mapping_unmap_writable(struct address_space *mapping)
521 {
522         atomic_dec(&mapping->i_mmap_writable);
523 }
524 
525 static inline int mapping_deny_writable(struct address_space *mapping)
526 {
527         return atomic_dec_unless_positive(&mapping->i_mmap_writable) ?
528                 0 : -EBUSY;
529 }
530 
531 static inline void mapping_allow_writable(struct address_space *mapping)
532 {
533         atomic_inc(&mapping->i_mmap_writable);
534 }
535 
536 /*
537  * Use sequence counter to get consistent i_size on 32-bit processors.
538  */
539 #if BITS_PER_LONG==32 && defined(CONFIG_SMP)
540 #include <linux/seqlock.h>
541 #define __NEED_I_SIZE_ORDERED
542 #define i_size_ordered_init(inode) seqcount_init(&inode->i_size_seqcount)
543 #else
544 #define i_size_ordered_init(inode) do { } while (0)
545 #endif
546 
547 struct posix_acl;
548 #define ACL_NOT_CACHED ((void *)(-1))
549 
550 #define IOP_FASTPERM    0x0001
551 #define IOP_LOOKUP      0x0002
552 #define IOP_NOFOLLOW    0x0004
553 
554 /*
555  * Keep mostly read-only and often accessed (especially for
556  * the RCU path lookup and 'stat' data) fields at the beginning
557  * of the 'struct inode'
558  */
559 struct inode {
560         umode_t                 i_mode;
561         unsigned short          i_opflags;
562         kuid_t                  i_uid;
563         kgid_t                  i_gid;
564         unsigned int            i_flags;
565 
566 #ifdef CONFIG_FS_POSIX_ACL
567         struct posix_acl        *i_acl;
568         struct posix_acl        *i_default_acl;
569 #endif
570 
571         const struct inode_operations   *i_op;
572         struct super_block      *i_sb;
573         struct address_space    *i_mapping;
574 
575 #ifdef CONFIG_SECURITY
576         void                    *i_security;
577 #endif
578 
579         /* Stat data, not accessed from path walking */
580         unsigned long           i_ino;
581         /*
582          * Filesystems may only read i_nlink directly.  They shall use the
583          * following functions for modification:
584          *
585          *    (set|clear|inc|drop)_nlink
586          *    inode_(inc|dec)_link_count
587          */
588         union {
589                 const unsigned int i_nlink;
590                 unsigned int __i_nlink;
591         };
592         dev_t                   i_rdev;
593         loff_t                  i_size;
594         struct timespec         i_atime;
595         struct timespec         i_mtime;
596         struct timespec         i_ctime;
597         spinlock_t              i_lock; /* i_blocks, i_bytes, maybe i_size */
598         unsigned short          i_bytes;
599         unsigned int            i_blkbits;
600         blkcnt_t                i_blocks;
601 
602 #ifdef __NEED_I_SIZE_ORDERED
603         seqcount_t              i_size_seqcount;
604 #endif
605 
606         /* Misc */
607         unsigned long           i_state;
608         struct mutex            i_mutex;
609 
610         unsigned long           dirtied_when;   /* jiffies of first dirtying */
611 
612         struct hlist_node       i_hash;
613         struct list_head        i_wb_list;      /* backing dev IO list */
614         struct list_head        i_lru;          /* inode LRU list */
615         struct list_head        i_sb_list;
616         union {
617                 struct hlist_head       i_dentry;
618                 struct rcu_head         i_rcu;
619         };
620         u64                     i_version;
621         atomic_t                i_count;
622         atomic_t                i_dio_count;
623         atomic_t                i_writecount;
624 #ifdef CONFIG_IMA
625         atomic_t                i_readcount; /* struct files open RO */
626 #endif
627         const struct file_operations    *i_fop; /* former ->i_op->default_file_ops */
628         struct file_lock        *i_flock;
629         struct address_space    i_data;
630         struct list_head        i_devices;
631         union {
632                 struct pipe_inode_info  *i_pipe;
633                 struct block_device     *i_bdev;
634                 struct cdev             *i_cdev;
635         };
636 
637         __u32                   i_generation;
638 
639 #ifdef CONFIG_FSNOTIFY
640         __u32                   i_fsnotify_mask; /* all events this inode cares about */
641         struct hlist_head       i_fsnotify_marks;
642 #endif
643 
644         void                    *i_private; /* fs or device private pointer */
645 };
646 
647 static inline int inode_unhashed(struct inode *inode)
648 {
649         return hlist_unhashed(&inode->i_hash);
650 }
651 
652 /*
653  * inode->i_mutex nesting subclasses for the lock validator:
654  *
655  * 0: the object of the current VFS operation
656  * 1: parent
657  * 2: child/target
658  * 3: xattr
659  * 4: second non-directory
660  * 5: second parent (when locking independent directories in rename)
661  *
662  * I_MUTEX_NONDIR2 is for certain operations (such as rename) which lock two
663  * non-directories at once.
664  *
665  * The locking order between these classes is
666  * parent[2] -> child -> grandchild -> normal -> xattr -> second non-directory
667  */
668 enum inode_i_mutex_lock_class
669 {
670         I_MUTEX_NORMAL,
671         I_MUTEX_PARENT,
672         I_MUTEX_CHILD,
673         I_MUTEX_XATTR,
674         I_MUTEX_NONDIR2,
675         I_MUTEX_PARENT2,
676 };
677 
678 void lock_two_nondirectories(struct inode *, struct inode*);
679 void unlock_two_nondirectories(struct inode *, struct inode*);
680 
681 /*
682  * NOTE: in a 32bit arch with a preemptable kernel and
683  * an UP compile the i_size_read/write must be atomic
684  * with respect to the local cpu (unlike with preempt disabled),
685  * but they don't need to be atomic with respect to other cpus like in
686  * true SMP (so they need either to either locally disable irq around
687  * the read or for example on x86 they can be still implemented as a
688  * cmpxchg8b without the need of the lock prefix). For SMP compiles
689  * and 64bit archs it makes no difference if preempt is enabled or not.
690  */
691 static inline loff_t i_size_read(const struct inode *inode)
692 {
693 #if BITS_PER_LONG==32 && defined(CONFIG_SMP)
694         loff_t i_size;
695         unsigned int seq;
696 
697         do {
698                 seq = read_seqcount_begin(&inode->i_size_seqcount);
699                 i_size = inode->i_size;
700         } while (read_seqcount_retry(&inode->i_size_seqcount, seq));
701         return i_size;
702 #elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPT)
703         loff_t i_size;
704 
705         preempt_disable();
706         i_size = inode->i_size;
707         preempt_enable();
708         return i_size;
709 #else
710         return inode->i_size;
711 #endif
712 }
713 
714 /*
715  * NOTE: unlike i_size_read(), i_size_write() does need locking around it
716  * (normally i_mutex), otherwise on 32bit/SMP an update of i_size_seqcount
717  * can be lost, resulting in subsequent i_size_read() calls spinning forever.
718  */
719 static inline void i_size_write(struct inode *inode, loff_t i_size)
720 {
721 #if BITS_PER_LONG==32 && defined(CONFIG_SMP)
722         preempt_disable();
723         write_seqcount_begin(&inode->i_size_seqcount);
724         inode->i_size = i_size;
725         write_seqcount_end(&inode->i_size_seqcount);
726         preempt_enable();
727 #elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPT)
728         preempt_disable();
729         inode->i_size = i_size;
730         preempt_enable();
731 #else
732         inode->i_size = i_size;
733 #endif
734 }
735 
736 /* Helper functions so that in most cases filesystems will
737  * not need to deal directly with kuid_t and kgid_t and can
738  * instead deal with the raw numeric values that are stored
739  * in the filesystem.
740  */
741 static inline uid_t i_uid_read(const struct inode *inode)
742 {
743         return from_kuid(&init_user_ns, inode->i_uid);
744 }
745 
746 static inline gid_t i_gid_read(const struct inode *inode)
747 {
748         return from_kgid(&init_user_ns, inode->i_gid);
749 }
750 
751 static inline void i_uid_write(struct inode *inode, uid_t uid)
752 {
753         inode->i_uid = make_kuid(&init_user_ns, uid);
754 }
755 
756 static inline void i_gid_write(struct inode *inode, gid_t gid)
757 {
758         inode->i_gid = make_kgid(&init_user_ns, gid);
759 }
760 
761 static inline unsigned iminor(const struct inode *inode)
762 {
763         return MINOR(inode->i_rdev);
764 }
765 
766 static inline unsigned imajor(const struct inode *inode)
767 {
768         return MAJOR(inode->i_rdev);
769 }
770 
771 extern struct block_device *I_BDEV(struct inode *inode);
772 
773 struct fown_struct {
774         rwlock_t lock;          /* protects pid, uid, euid fields */
775         struct pid *pid;        /* pid or -pgrp where SIGIO should be sent */
776         enum pid_type pid_type; /* Kind of process group SIGIO should be sent to */
777         kuid_t uid, euid;       /* uid/euid of process setting the owner */
778         int signum;             /* posix.1b rt signal to be delivered on IO */
779 };
780 
781 /*
782  * Track a single file's readahead state
783  */
784 struct file_ra_state {
785         pgoff_t start;                  /* where readahead started */
786         unsigned int size;              /* # of readahead pages */
787         unsigned int async_size;        /* do asynchronous readahead when
788                                            there are only # of pages ahead */
789 
790         unsigned int ra_pages;          /* Maximum readahead window */
791         unsigned int mmap_miss;         /* Cache miss stat for mmap accesses */
792         loff_t prev_pos;                /* Cache last read() position */
793 };
794 
795 /*
796  * Check if @index falls in the readahead windows.
797  */
798 static inline int ra_has_index(struct file_ra_state *ra, pgoff_t index)
799 {
800         return (index >= ra->start &&
801                 index <  ra->start + ra->size);
802 }
803 
804 struct file {
805         union {
806                 struct llist_node       fu_llist;
807                 struct rcu_head         fu_rcuhead;
808         } f_u;
809         struct path             f_path;
810         struct inode            *f_inode;       /* cached value */
811         const struct file_operations    *f_op;
812 
813         /*
814          * Protects f_ep_links, f_flags.
815          * Must not be taken from IRQ context.
816          */
817         spinlock_t              f_lock;
818         atomic_long_t           f_count;
819         unsigned int            f_flags;
820         fmode_t                 f_mode;
821         struct mutex            f_pos_lock;
822         loff_t                  f_pos;
823         struct fown_struct      f_owner;
824         const struct cred       *f_cred;
825         struct file_ra_state    f_ra;
826 
827         u64                     f_version;
828 #ifdef CONFIG_SECURITY
829         void                    *f_security;
830 #endif
831         /* needed for tty driver, and maybe others */
832         void                    *private_data;
833 
834 #ifdef CONFIG_EPOLL
835         /* Used by fs/eventpoll.c to link all the hooks to this file */
836         struct list_head        f_ep_links;
837         struct list_head        f_tfile_llink;
838 #endif /* #ifdef CONFIG_EPOLL */
839         struct address_space    *f_mapping;
840 } __attribute__((aligned(4)));  /* lest something weird decides that 2 is OK */
841 
842 struct file_handle {
843         __u32 handle_bytes;
844         int handle_type;
845         /* file identifier */
846         unsigned char f_handle[0];
847 };
848 
849 static inline struct file *get_file(struct file *f)
850 {
851         atomic_long_inc(&f->f_count);
852         return f;
853 }
854 #define fput_atomic(x)  atomic_long_add_unless(&(x)->f_count, -1, 1)
855 #define file_count(x)   atomic_long_read(&(x)->f_count)
856 
857 #define MAX_NON_LFS     ((1UL<<31) - 1)
858 
859 /* Page cache limit. The filesystems should put that into their s_maxbytes 
860    limits, otherwise bad things can happen in VM. */ 
861 #if BITS_PER_LONG==32
862 #define MAX_LFS_FILESIZE        (((loff_t)PAGE_CACHE_SIZE << (BITS_PER_LONG-1))-1) 
863 #elif BITS_PER_LONG==64
864 #define MAX_LFS_FILESIZE        ((loff_t)0x7fffffffffffffffLL)
865 #endif
866 
867 #define FL_POSIX        1
868 #define FL_FLOCK        2
869 #define FL_DELEG        4       /* NFSv4 delegation */
870 #define FL_ACCESS       8       /* not trying to lock, just looking */
871 #define FL_EXISTS       16      /* when unlocking, test for existence */
872 #define FL_LEASE        32      /* lease held on this file */
873 #define FL_CLOSE        64      /* unlock on close */
874 #define FL_SLEEP        128     /* A blocking lock */
875 #define FL_DOWNGRADE_PENDING    256 /* Lease is being downgraded */
876 #define FL_UNLOCK_PENDING       512 /* Lease is being broken */
877 #define FL_OFDLCK       1024    /* lock is "owned" by struct file */
878 
879 /*
880  * Special return value from posix_lock_file() and vfs_lock_file() for
881  * asynchronous locking.
882  */
883 #define FILE_LOCK_DEFERRED 1
884 
885 /* legacy typedef, should eventually be removed */
886 typedef void *fl_owner_t;
887 
888 struct file_lock_operations {
889         void (*fl_copy_lock)(struct file_lock *, struct file_lock *);
890         void (*fl_release_private)(struct file_lock *);
891 };
892 
893 struct lock_manager_operations {
894         int (*lm_compare_owner)(struct file_lock *, struct file_lock *);
895         unsigned long (*lm_owner_key)(struct file_lock *);
896         void (*lm_get_owner)(struct file_lock *, struct file_lock *);
897         void (*lm_put_owner)(struct file_lock *);
898         void (*lm_notify)(struct file_lock *);  /* unblock callback */
899         int (*lm_grant)(struct file_lock *, int);
900         bool (*lm_break)(struct file_lock *);
901         int (*lm_change)(struct file_lock **, int, struct list_head *);
902         void (*lm_setup)(struct file_lock *, void **);
903 };
904 
905 struct lock_manager {
906         struct list_head list;
907 };
908 
909 struct net;
910 void locks_start_grace(struct net *, struct lock_manager *);
911 void locks_end_grace(struct lock_manager *);
912 int locks_in_grace(struct net *);
913 
914 /* that will die - we need it for nfs_lock_info */
915 #include <linux/nfs_fs_i.h>
916 
917 /*
918  * struct file_lock represents a generic "file lock". It's used to represent
919  * POSIX byte range locks, BSD (flock) locks, and leases. It's important to
920  * note that the same struct is used to represent both a request for a lock and
921  * the lock itself, but the same object is never used for both.
922  *
923  * FIXME: should we create a separate "struct lock_request" to help distinguish
924  * these two uses?
925  *
926  * The i_flock list is ordered by:
927  *
928  * 1) lock type -- FL_LEASEs first, then FL_FLOCK, and finally FL_POSIX
929  * 2) lock owner
930  * 3) lock range start
931  * 4) lock range end
932  *
933  * Obviously, the last two criteria only matter for POSIX locks.
934  */
935 struct file_lock {
936         struct file_lock *fl_next;      /* singly linked list for this inode  */
937         struct hlist_node fl_link;      /* node in global lists */
938         struct list_head fl_block;      /* circular list of blocked processes */
939         fl_owner_t fl_owner;
940         unsigned int fl_flags;
941         unsigned char fl_type;
942         unsigned int fl_pid;
943         int fl_link_cpu;                /* what cpu's list is this on? */
944         struct pid *fl_nspid;
945         wait_queue_head_t fl_wait;
946         struct file *fl_file;
947         loff_t fl_start;
948         loff_t fl_end;
949 
950         struct fasync_struct *  fl_fasync; /* for lease break notifications */
951         /* for lease breaks: */
952         unsigned long fl_break_time;
953         unsigned long fl_downgrade_time;
954 
955         const struct file_lock_operations *fl_ops;      /* Callbacks for filesystems */
956         const struct lock_manager_operations *fl_lmops; /* Callbacks for lockmanagers */
957         union {
958                 struct nfs_lock_info    nfs_fl;
959                 struct nfs4_lock_info   nfs4_fl;
960                 struct {
961                         struct list_head link;  /* link in AFS vnode's pending_locks list */
962                         int state;              /* state of grant or error if -ve */
963                 } afs;
964         } fl_u;
965 };
966 
967 /* The following constant reflects the upper bound of the file/locking space */
968 #ifndef OFFSET_MAX
969 #define INT_LIMIT(x)    (~((x)1 << (sizeof(x)*8 - 1)))
970 #define OFFSET_MAX      INT_LIMIT(loff_t)
971 #define OFFT_OFFSET_MAX INT_LIMIT(off_t)
972 #endif
973 
974 #include <linux/fcntl.h>
975 
976 extern void send_sigio(struct fown_struct *fown, int fd, int band);
977 
978 #ifdef CONFIG_FILE_LOCKING
979 extern int fcntl_getlk(struct file *, unsigned int, struct flock __user *);
980 extern int fcntl_setlk(unsigned int, struct file *, unsigned int,
981                         struct flock __user *);
982 
983 #if BITS_PER_LONG == 32
984 extern int fcntl_getlk64(struct file *, unsigned int, struct flock64 __user *);
985 extern int fcntl_setlk64(unsigned int, struct file *, unsigned int,
986                         struct flock64 __user *);
987 #endif
988 
989 extern int fcntl_setlease(unsigned int fd, struct file *filp, long arg);
990 extern int fcntl_getlease(struct file *filp);
991 
992 /* fs/locks.c */
993 void locks_free_lock(struct file_lock *fl);
994 extern void locks_init_lock(struct file_lock *);
995 extern struct file_lock * locks_alloc_lock(void);
996 extern void locks_copy_lock(struct file_lock *, struct file_lock *);
997 extern void locks_copy_conflock(struct file_lock *, struct file_lock *);
998 extern void locks_remove_posix(struct file *, fl_owner_t);
999 extern void locks_remove_file(struct file *);
1000 extern void locks_release_private(struct file_lock *);
1001 extern void posix_test_lock(struct file *, struct file_lock *);
1002 extern int posix_lock_file(struct file *, struct file_lock *, struct file_lock *);
1003 extern int posix_lock_file_wait(struct file *, struct file_lock *);
1004 extern int posix_unblock_lock(struct file_lock *);
1005 extern int vfs_test_lock(struct file *, struct file_lock *);
1006 extern int vfs_lock_file(struct file *, unsigned int, struct file_lock *, struct file_lock *);
1007 extern int vfs_cancel_lock(struct file *filp, struct file_lock *fl);
1008 extern int flock_lock_file_wait(struct file *filp, struct file_lock *fl);
1009 extern int __break_lease(struct inode *inode, unsigned int flags, unsigned int type);
1010 extern void lease_get_mtime(struct inode *, struct timespec *time);
1011 extern int generic_setlease(struct file *, long, struct file_lock **, void **priv);
1012 extern int vfs_setlease(struct file *, long, struct file_lock **, void **);
1013 extern int lease_modify(struct file_lock **, int, struct list_head *);
1014 #else /* !CONFIG_FILE_LOCKING */
1015 static inline int fcntl_getlk(struct file *file, unsigned int cmd,
1016                               struct flock __user *user)
1017 {
1018         return -EINVAL;
1019 }
1020 
1021 static inline int fcntl_setlk(unsigned int fd, struct file *file,
1022                               unsigned int cmd, struct flock __user *user)
1023 {
1024         return -EACCES;
1025 }
1026 
1027 #if BITS_PER_LONG == 32
1028 static inline int fcntl_getlk64(struct file *file, unsigned int cmd,
1029                                 struct flock64 __user *user)
1030 {
1031         return -EINVAL;
1032 }
1033 
1034 static inline int fcntl_setlk64(unsigned int fd, struct file *file,
1035                                 unsigned int cmd, struct flock64 __user *user)
1036 {
1037         return -EACCES;
1038 }
1039 #endif
1040 static inline int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
1041 {
1042         return -EINVAL;
1043 }
1044 
1045 static inline int fcntl_getlease(struct file *filp)
1046 {
1047         return F_UNLCK;
1048 }
1049 
1050 static inline void locks_init_lock(struct file_lock *fl)
1051 {
1052         return;
1053 }
1054 
1055 static inline void locks_copy_conflock(struct file_lock *new, struct file_lock *fl)
1056 {
1057         return;
1058 }
1059 
1060 static inline void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
1061 {
1062         return;
1063 }
1064 
1065 static inline void locks_remove_posix(struct file *filp, fl_owner_t owner)
1066 {
1067         return;
1068 }
1069 
1070 static inline void locks_remove_file(struct file *filp)
1071 {
1072         return;
1073 }
1074 
1075 static inline void posix_test_lock(struct file *filp, struct file_lock *fl)
1076 {
1077         return;
1078 }
1079 
1080 static inline int posix_lock_file(struct file *filp, struct file_lock *fl,
1081                                   struct file_lock *conflock)
1082 {
1083         return -ENOLCK;
1084 }
1085 
1086 static inline int posix_lock_file_wait(struct file *filp, struct file_lock *fl)
1087 {
1088         return -ENOLCK;
1089 }
1090 
1091 static inline int posix_unblock_lock(struct file_lock *waiter)
1092 {
1093         return -ENOENT;
1094 }
1095 
1096 static inline int vfs_test_lock(struct file *filp, struct file_lock *fl)
1097 {
1098         return 0;
1099 }
1100 
1101 static inline int vfs_lock_file(struct file *filp, unsigned int cmd,
1102                                 struct file_lock *fl, struct file_lock *conf)
1103 {
1104         return -ENOLCK;
1105 }
1106 
1107 static inline int vfs_cancel_lock(struct file *filp, struct file_lock *fl)
1108 {
1109         return 0;
1110 }
1111 
1112 static inline int flock_lock_file_wait(struct file *filp,
1113                                        struct file_lock *request)
1114 {
1115         return -ENOLCK;
1116 }
1117 
1118 static inline int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
1119 {
1120         return 0;
1121 }
1122 
1123 static inline void lease_get_mtime(struct inode *inode, struct timespec *time)
1124 {
1125         return;
1126 }
1127 
1128 static inline int generic_setlease(struct file *filp, long arg,
1129                                     struct file_lock **flp, void **priv)
1130 {
1131         return -EINVAL;
1132 }
1133 
1134 static inline int vfs_setlease(struct file *filp, long arg,
1135                                struct file_lock **lease, void **priv)
1136 {
1137         return -EINVAL;
1138 }
1139 
1140 static inline int lease_modify(struct file_lock **before, int arg,
1141                                struct list_head *dispose)
1142 {
1143         return -EINVAL;
1144 }
1145 #endif /* !CONFIG_FILE_LOCKING */
1146 
1147 
1148 struct fasync_struct {
1149         spinlock_t              fa_lock;
1150         int                     magic;
1151         int                     fa_fd;
1152         struct fasync_struct    *fa_next; /* singly linked list */
1153         struct file             *fa_file;
1154         struct rcu_head         fa_rcu;
1155 };
1156 
1157 #define FASYNC_MAGIC 0x4601
1158 
1159 /* SMP safe fasync helpers: */
1160 extern int fasync_helper(int, struct file *, int, struct fasync_struct **);
1161 extern struct fasync_struct *fasync_insert_entry(int, struct file *, struct fasync_struct **, struct fasync_struct *);
1162 extern int fasync_remove_entry(struct file *, struct fasync_struct **);
1163 extern struct fasync_struct *fasync_alloc(void);
1164 extern void fasync_free(struct fasync_struct *);
1165 
1166 /* can be called from interrupts */
1167 extern void kill_fasync(struct fasync_struct **, int, int);
1168 
1169 extern void __f_setown(struct file *filp, struct pid *, enum pid_type, int force);
1170 extern void f_setown(struct file *filp, unsigned long arg, int force);
1171 extern void f_delown(struct file *filp);
1172 extern pid_t f_getown(struct file *filp);
1173 extern int send_sigurg(struct fown_struct *fown);
1174 
1175 struct mm_struct;
1176 
1177 /*
1178  *      Umount options
1179  */
1180 
1181 #define MNT_FORCE       0x00000001      /* Attempt to forcibily umount */
1182 #define MNT_DETACH      0x00000002      /* Just detach from the tree */
1183 #define MNT_EXPIRE      0x00000004      /* Mark for expiry */
1184 #define UMOUNT_NOFOLLOW 0x00000008      /* Don't follow symlink on umount */
1185 #define UMOUNT_UNUSED   0x80000000      /* Flag guaranteed to be unused */
1186 
1187 extern struct list_head super_blocks;
1188 extern spinlock_t sb_lock;
1189 
1190 /* Possible states of 'frozen' field */
1191 enum {
1192         SB_UNFROZEN = 0,                /* FS is unfrozen */
1193         SB_FREEZE_WRITE = 1,            /* Writes, dir ops, ioctls frozen */
1194         SB_FREEZE_PAGEFAULT = 2,        /* Page faults stopped as well */
1195         SB_FREEZE_FS = 3,               /* For internal FS use (e.g. to stop
1196                                          * internal threads if needed) */
1197         SB_FREEZE_COMPLETE = 4,         /* ->freeze_fs finished successfully */
1198 };
1199 
1200 #define SB_FREEZE_LEVELS (SB_FREEZE_COMPLETE - 1)
1201 
1202 struct sb_writers {
1203         /* Counters for counting writers at each level */
1204         struct percpu_counter   counter[SB_FREEZE_LEVELS];
1205         wait_queue_head_t       wait;           /* queue for waiting for
1206                                                    writers / faults to finish */
1207         int                     frozen;         /* Is sb frozen? */
1208         wait_queue_head_t       wait_unfrozen;  /* queue for waiting for
1209                                                    sb to be thawed */
1210 #ifdef CONFIG_DEBUG_LOCK_ALLOC
1211         struct lockdep_map      lock_map[SB_FREEZE_LEVELS];
1212 #endif
1213 };
1214 
1215 struct super_block {
1216         struct list_head        s_list;         /* Keep this first */
1217         dev_t                   s_dev;          /* search index; _not_ kdev_t */
1218         unsigned char           s_blocksize_bits;
1219         unsigned long           s_blocksize;
1220         loff_t                  s_maxbytes;     /* Max file size */
1221         struct file_system_type *s_type;
1222         const struct super_operations   *s_op;
1223         const struct dquot_operations   *dq_op;
1224         const struct quotactl_ops       *s_qcop;
1225         const struct export_operations *s_export_op;
1226         unsigned long           s_flags;
1227         unsigned long           s_magic;
1228         struct dentry           *s_root;
1229         struct rw_semaphore     s_umount;
1230         int                     s_count;
1231         atomic_t                s_active;
1232 #ifdef CONFIG_SECURITY
1233         void                    *s_security;
1234 #endif
1235         const struct xattr_handler **s_xattr;
1236 
1237         struct list_head        s_inodes;       /* all inodes */
1238         struct hlist_bl_head    s_anon;         /* anonymous dentries for (nfs) exporting */
1239         struct list_head        s_mounts;       /* list of mounts; _not_ for fs use */
1240         struct block_device     *s_bdev;
1241         struct backing_dev_info *s_bdi;
1242         struct mtd_info         *s_mtd;
1243         struct hlist_node       s_instances;
1244         unsigned int            s_quota_types;  /* Bitmask of supported quota types */
1245         struct quota_info       s_dquot;        /* Diskquota specific options */
1246 
1247         struct sb_writers       s_writers;
1248 
1249         char s_id[32];                          /* Informational name */
1250         u8 s_uuid[16];                          /* UUID */
1251 
1252         void                    *s_fs_info;     /* Filesystem private info */
1253         unsigned int            s_max_links;
1254         fmode_t                 s_mode;
1255 
1256         /* Granularity of c/m/atime in ns.
1257            Cannot be worse than a second */
1258         u32                s_time_gran;
1259 
1260         /*
1261          * The next field is for VFS *only*. No filesystems have any business
1262          * even looking at it. You had been warned.
1263          */
1264         struct mutex s_vfs_rename_mutex;        /* Kludge */
1265 
1266         /*
1267          * Filesystem subtype.  If non-empty the filesystem type field
1268          * in /proc/mounts will be "type.subtype"
1269          */
1270         char *s_subtype;
1271 
1272         /*
1273          * Saved mount options for lazy filesystems using
1274          * generic_show_options()
1275          */
1276         char __rcu *s_options;
1277         const struct dentry_operations *s_d_op; /* default d_op for dentries */
1278 
1279         /*
1280          * Saved pool identifier for cleancache (-1 means none)
1281          */
1282         int cleancache_poolid;
1283 
1284         struct shrinker s_shrink;       /* per-sb shrinker handle */
1285 
1286         /* Number of inodes with nlink == 0 but still referenced */
1287         atomic_long_t s_remove_count;
1288 
1289         /* Being remounted read-only */
1290         int s_readonly_remount;
1291 
1292         /* AIO completions deferred from interrupt context */
1293         struct workqueue_struct *s_dio_done_wq;
1294         struct hlist_head s_pins;
1295 
1296         /*
1297          * Keep the lru lists last in the structure so they always sit on their
1298          * own individual cachelines.
1299          */
1300         struct list_lru         s_dentry_lru ____cacheline_aligned_in_smp;
1301         struct list_lru         s_inode_lru ____cacheline_aligned_in_smp;
1302         struct rcu_head         rcu;
1303 
1304         /*
1305          * Indicates how deep in a filesystem stack this SB is
1306          */
1307         int s_stack_depth;
1308 };
1309 
1310 extern struct timespec current_fs_time(struct super_block *sb);
1311 
1312 /*
1313  * Snapshotting support.
1314  */
1315 
1316 void __sb_end_write(struct super_block *sb, int level);
1317 int __sb_start_write(struct super_block *sb, int level, bool wait);
1318 
1319 /**
1320  * sb_end_write - drop write access to a superblock
1321  * @sb: the super we wrote to
1322  *
1323  * Decrement number of writers to the filesystem. Wake up possible waiters
1324  * wanting to freeze the filesystem.
1325  */
1326 static inline void sb_end_write(struct super_block *sb)
1327 {
1328         __sb_end_write(sb, SB_FREEZE_WRITE);
1329 }
1330 
1331 /**
1332  * sb_end_pagefault - drop write access to a superblock from a page fault
1333  * @sb: the super we wrote to
1334  *
1335  * Decrement number of processes handling write page fault to the filesystem.
1336  * Wake up possible waiters wanting to freeze the filesystem.
1337  */
1338 static inline void sb_end_pagefault(struct super_block *sb)
1339 {
1340         __sb_end_write(sb, SB_FREEZE_PAGEFAULT);
1341 }
1342 
1343 /**
1344  * sb_end_intwrite - drop write access to a superblock for internal fs purposes
1345  * @sb: the super we wrote to
1346  *
1347  * Decrement fs-internal number of writers to the filesystem.  Wake up possible
1348  * waiters wanting to freeze the filesystem.
1349  */
1350 static inline void sb_end_intwrite(struct super_block *sb)
1351 {
1352         __sb_end_write(sb, SB_FREEZE_FS);
1353 }
1354 
1355 /**
1356  * sb_start_write - get write access to a superblock
1357  * @sb: the super we write to
1358  *
1359  * When a process wants to write data or metadata to a file system (i.e. dirty
1360  * a page or an inode), it should embed the operation in a sb_start_write() -
1361  * sb_end_write() pair to get exclusion against file system freezing. This
1362  * function increments number of writers preventing freezing. If the file
1363  * system is already frozen, the function waits until the file system is
1364  * thawed.
1365  *
1366  * Since freeze protection behaves as a lock, users have to preserve
1367  * ordering of freeze protection and other filesystem locks. Generally,
1368  * freeze protection should be the outermost lock. In particular, we have:
1369  *
1370  * sb_start_write
1371  *   -> i_mutex                 (write path, truncate, directory ops, ...)
1372  *   -> s_umount                (freeze_super, thaw_super)
1373  */
1374 static inline void sb_start_write(struct super_block *sb)
1375 {
1376         __sb_start_write(sb, SB_FREEZE_WRITE, true);
1377 }
1378 
1379 static inline int sb_start_write_trylock(struct super_block *sb)
1380 {
1381         return __sb_start_write(sb, SB_FREEZE_WRITE, false);
1382 }
1383 
1384 /**
1385  * sb_start_pagefault - get write access to a superblock from a page fault
1386  * @sb: the super we write to
1387  *
1388  * When a process starts handling write page fault, it should embed the
1389  * operation into sb_start_pagefault() - sb_end_pagefault() pair to get
1390  * exclusion against file system freezing. This is needed since the page fault
1391  * is going to dirty a page. This function increments number of running page
1392  * faults preventing freezing. If the file system is already frozen, the
1393  * function waits until the file system is thawed.
1394  *
1395  * Since page fault freeze protection behaves as a lock, users have to preserve
1396  * ordering of freeze protection and other filesystem locks. It is advised to
1397  * put sb_start_pagefault() close to mmap_sem in lock ordering. Page fault
1398  * handling code implies lock dependency:
1399  *
1400  * mmap_sem
1401  *   -> sb_start_pagefault
1402  */
1403 static inline void sb_start_pagefault(struct super_block *sb)
1404 {
1405         __sb_start_write(sb, SB_FREEZE_PAGEFAULT, true);
1406 }
1407 
1408 /*
1409  * sb_start_intwrite - get write access to a superblock for internal fs purposes
1410  * @sb: the super we write to
1411  *
1412  * This is the third level of protection against filesystem freezing. It is
1413  * free for use by a filesystem. The only requirement is that it must rank
1414  * below sb_start_pagefault.
1415  *
1416  * For example filesystem can call sb_start_intwrite() when starting a
1417  * transaction which somewhat eases handling of freezing for internal sources
1418  * of filesystem changes (internal fs threads, discarding preallocation on file
1419  * close, etc.).
1420  */
1421 static inline void sb_start_intwrite(struct super_block *sb)
1422 {
1423         __sb_start_write(sb, SB_FREEZE_FS, true);
1424 }
1425 
1426 
1427 extern bool inode_owner_or_capable(const struct inode *inode);
1428 
1429 /*
1430  * VFS helper functions..
1431  */
1432 extern int vfs_create(struct inode *, struct dentry *, umode_t, bool);
1433 extern int vfs_mkdir(struct inode *, struct dentry *, umode_t);
1434 extern int vfs_mknod(struct inode *, struct dentry *, umode_t, dev_t);
1435 extern int vfs_symlink(struct inode *, struct dentry *, const char *);
1436 extern int vfs_link(struct dentry *, struct inode *, struct dentry *, struct inode **);
1437 extern int vfs_rmdir(struct inode *, struct dentry *);
1438 extern int vfs_unlink(struct inode *, struct dentry *, struct inode **);
1439 extern int vfs_rename(struct inode *, struct dentry *, struct inode *, struct dentry *, struct inode **, unsigned int);
1440 extern int vfs_whiteout(struct inode *, struct dentry *);
1441 
1442 /*
1443  * VFS dentry helper functions.
1444  */
1445 extern void dentry_unhash(struct dentry *dentry);
1446 
1447 /*
1448  * VFS file helper functions.
1449  */
1450 extern void inode_init_owner(struct inode *inode, const struct inode *dir,
1451                         umode_t mode);
1452 /*
1453  * VFS FS_IOC_FIEMAP helper definitions.
1454  */
1455 struct fiemap_extent_info {
1456         unsigned int fi_flags;          /* Flags as passed from user */
1457         unsigned int fi_extents_mapped; /* Number of mapped extents */
1458         unsigned int fi_extents_max;    /* Size of fiemap_extent array */
1459         struct fiemap_extent __user *fi_extents_start; /* Start of
1460                                                         fiemap_extent array */
1461 };
1462 int fiemap_fill_next_extent(struct fiemap_extent_info *info, u64 logical,
1463                             u64 phys, u64 len, u32 flags);
1464 int fiemap_check_flags(struct fiemap_extent_info *fieinfo, u32 fs_flags);
1465 
1466 /*
1467  * File types
1468  *
1469  * NOTE! These match bits 12..15 of stat.st_mode
1470  * (ie "(i_mode >> 12) & 15").
1471  */
1472 #define DT_UNKNOWN      0
1473 #define DT_FIFO         1
1474 #define DT_CHR          2
1475 #define DT_DIR          4
1476 #define DT_BLK          6
1477 #define DT_REG          8
1478 #define DT_LNK          10
1479 #define DT_SOCK         12
1480 #define DT_WHT          14
1481 
1482 /*
1483  * This is the "filldir" function type, used by readdir() to let
1484  * the kernel specify what kind of dirent layout it wants to have.
1485  * This allows the kernel to read directories into kernel space or
1486  * to have different dirent layouts depending on the binary type.
1487  */
1488 struct dir_context;
1489 typedef int (*filldir_t)(struct dir_context *, const char *, int, loff_t, u64,
1490                          unsigned);
1491 
1492 struct dir_context {
1493         const filldir_t actor;
1494         loff_t pos;
1495 };
1496 
1497 struct block_device_operations;
1498 
1499 /* These macros are for out of kernel modules to test that
1500  * the kernel supports the unlocked_ioctl and compat_ioctl
1501  * fields in struct file_operations. */
1502 #define HAVE_COMPAT_IOCTL 1
1503 #define HAVE_UNLOCKED_IOCTL 1
1504 
1505 struct iov_iter;
1506 
1507 struct file_operations {
1508         struct module *owner;
1509         loff_t (*llseek) (struct file *, loff_t, int);
1510         ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);
1511         ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
1512         ssize_t (*aio_read) (struct kiocb *, const struct iovec *, unsigned long, loff_t);
1513         ssize_t (*aio_write) (struct kiocb *, const struct iovec *, unsigned long, loff_t);
1514         ssize_t (*read_iter) (struct kiocb *, struct iov_iter *);
1515         ssize_t (*write_iter) (struct kiocb *, struct iov_iter *);
1516         int (*iterate) (struct file *, struct dir_context *);
1517         unsigned int (*poll) (struct file *, struct poll_table_struct *);
1518         long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
1519         long (*compat_ioctl) (struct file *, unsigned int, unsigned long);
1520         int (*mmap) (struct file *, struct vm_area_struct *);
1521         void (*mremap)(struct file *, struct vm_area_struct *);
1522         int (*open) (struct inode *, struct file *);
1523         int (*flush) (struct file *, fl_owner_t id);
1524         int (*release) (struct inode *, struct file *);
1525         int (*fsync) (struct file *, loff_t, loff_t, int datasync);
1526         int (*aio_fsync) (struct kiocb *, int datasync);
1527         int (*fasync) (int, struct file *, int);
1528         int (*lock) (struct file *, int, struct file_lock *);
1529         ssize_t (*sendpage) (struct file *, struct page *, int, size_t, loff_t *, int);
1530         unsigned long (*get_unmapped_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
1531         int (*check_flags)(int);
1532         int (*flock) (struct file *, int, struct file_lock *);
1533         ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, loff_t *, size_t, unsigned int);
1534         ssize_t (*splice_read)(struct file *, loff_t *, struct pipe_inode_info *, size_t, unsigned int);
1535         int (*setlease)(struct file *, long, struct file_lock **, void **);
1536         long (*fallocate)(struct file *file, int mode, loff_t offset,
1537                           loff_t len);
1538         void (*show_fdinfo)(struct seq_file *m, struct file *f);
1539 };
1540 
1541 struct inode_operations {
1542         struct dentry * (*lookup) (struct inode *,struct dentry *, unsigned int);
1543         void * (*follow_link) (struct dentry *, struct nameidata *);
1544         int (*permission) (struct inode *, int);
1545         struct posix_acl * (*get_acl)(struct inode *, int);
1546 
1547         int (*readlink) (struct dentry *, char __user *,int);
1548         void (*put_link) (struct dentry *, struct nameidata *, void *);
1549 
1550         int (*create) (struct inode *,struct dentry *, umode_t, bool);
1551         int (*link) (struct dentry *,struct inode *,struct dentry *);
1552         int (*unlink) (struct inode *,struct dentry *);
1553         int (*symlink) (struct inode *,struct dentry *,const char *);
1554         int (*mkdir) (struct inode *,struct dentry *,umode_t);
1555         int (*rmdir) (struct inode *,struct dentry *);
1556         int (*mknod) (struct inode *,struct dentry *,umode_t,dev_t);
1557         int (*rename) (struct inode *, struct dentry *,
1558                         struct inode *, struct dentry *);
1559         int (*rename2) (struct inode *, struct dentry *,
1560                         struct inode *, struct dentry *, unsigned int);
1561         int (*setattr) (struct dentry *, struct iattr *);
1562         int (*getattr) (struct vfsmount *mnt, struct dentry *, struct kstat *);
1563         int (*setxattr) (struct dentry *, const char *,const void *,size_t,int);
1564         ssize_t (*getxattr) (struct dentry *, const char *, void *, size_t);
1565         ssize_t (*listxattr) (struct dentry *, char *, size_t);
1566         int (*removexattr) (struct dentry *, const char *);
1567         int (*fiemap)(struct inode *, struct fiemap_extent_info *, u64 start,
1568                       u64 len);
1569         int (*update_time)(struct inode *, struct timespec *, int);
1570         int (*atomic_open)(struct inode *, struct dentry *,
1571                            struct file *, unsigned open_flag,
1572                            umode_t create_mode, int *opened);
1573         int (*tmpfile) (struct inode *, struct dentry *, umode_t);
1574         int (*set_acl)(struct inode *, struct posix_acl *, int);
1575 
1576         /* WARNING: probably going away soon, do not use! */
1577         int (*dentry_open)(struct dentry *, struct file *, const struct cred *);
1578 } ____cacheline_aligned;
1579 
1580 ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector,
1581                               unsigned long nr_segs, unsigned long fast_segs,
1582                               struct iovec *fast_pointer,
1583                               struct iovec **ret_pointer);
1584 
1585 extern ssize_t __vfs_read(struct file *, char __user *, size_t, loff_t *);
1586 extern ssize_t vfs_read(struct file *, char __user *, size_t, loff_t *);
1587 extern ssize_t vfs_write(struct file *, const char __user *, size_t, loff_t *);
1588 extern ssize_t vfs_readv(struct file *, const struct iovec __user *,
1589                 unsigned long, loff_t *);
1590 extern ssize_t vfs_writev(struct file *, const struct iovec __user *,
1591                 unsigned long, loff_t *);
1592 
1593 struct super_operations {
1594         struct inode *(*alloc_inode)(struct super_block *sb);
1595         void (*destroy_inode)(struct inode *);
1596 
1597         void (*dirty_inode) (struct inode *, int flags);
1598         int (*write_inode) (struct inode *, struct writeback_control *wbc);
1599         int (*drop_inode) (struct inode *);
1600         void (*evict_inode) (struct inode *);
1601         void (*put_super) (struct super_block *);
1602         int (*sync_fs)(struct super_block *sb, int wait);
1603         int (*freeze_super) (struct super_block *);
1604         int (*freeze_fs) (struct super_block *);
1605         int (*thaw_super) (struct super_block *);
1606         int (*unfreeze_fs) (struct super_block *);
1607         int (*statfs) (struct dentry *, struct kstatfs *);
1608         int (*remount_fs) (struct super_block *, int *, char *);
1609         void (*umount_begin) (struct super_block *);
1610 
1611         int (*show_options)(struct seq_file *, struct dentry *);
1612         int (*show_devname)(struct seq_file *, struct dentry *);
1613         int (*show_path)(struct seq_file *, struct dentry *);
1614         int (*show_stats)(struct seq_file *, struct dentry *);
1615 #ifdef CONFIG_QUOTA
1616         ssize_t (*quota_read)(struct super_block *, int, char *, size_t, loff_t);
1617         ssize_t (*quota_write)(struct super_block *, int, const char *, size_t, loff_t);
1618         struct dquot **(*get_dquots)(struct inode *);
1619 #endif
1620         int (*bdev_try_to_free_page)(struct super_block*, struct page*, gfp_t);
1621         long (*nr_cached_objects)(struct super_block *, int);
1622         long (*free_cached_objects)(struct super_block *, long, int);
1623 };
1624 
1625 /*
1626  * Inode flags - they have no relation to superblock flags now
1627  */
1628 #define S_SYNC          1       /* Writes are synced at once */
1629 #define S_NOATIME       2       /* Do not update access times */
1630 #define S_APPEND        4       /* Append-only file */
1631 #define S_IMMUTABLE     8       /* Immutable file */
1632 #define S_DEAD          16      /* removed, but still open directory */
1633 #define S_NOQUOTA       32      /* Inode is not counted to quota */
1634 #define S_DIRSYNC       64      /* Directory modifications are synchronous */
1635 #define S_NOCMTIME      128     /* Do not update file c/mtime */
1636 #define S_SWAPFILE      256     /* Do not truncate: swapon got its bmaps */
1637 #define S_PRIVATE       512     /* Inode is fs-internal */
1638 #define S_IMA           1024    /* Inode has an associated IMA struct */
1639 #define S_AUTOMOUNT     2048    /* Automount/referral quasi-directory */
1640 #define S_NOSEC         4096    /* no suid or xattr security attributes */
1641 
1642 /*
1643  * Note that nosuid etc flags are inode-specific: setting some file-system
1644  * flags just means all the inodes inherit those flags by default. It might be
1645  * possible to override it selectively if you really wanted to with some
1646  * ioctl() that is not currently implemented.
1647  *
1648  * Exception: MS_RDONLY is always applied to the entire file system.
1649  *
1650  * Unfortunately, it is possible to change a filesystems flags with it mounted
1651  * with files in use.  This means that all of the inodes will not have their
1652  * i_flags updated.  Hence, i_flags no longer inherit the superblock mount
1653  * flags, so these have to be checked separately. -- rmk@arm.uk.linux.org
1654  */
1655 #define __IS_FLG(inode, flg)    ((inode)->i_sb->s_flags & (flg))
1656 
1657 #define IS_RDONLY(inode)        ((inode)->i_sb->s_flags & MS_RDONLY)
1658 #define IS_SYNC(inode)          (__IS_FLG(inode, MS_SYNCHRONOUS) || \
1659                                         ((inode)->i_flags & S_SYNC))
1660 #define IS_DIRSYNC(inode)       (__IS_FLG(inode, MS_SYNCHRONOUS|MS_DIRSYNC) || \
1661                                         ((inode)->i_flags & (S_SYNC|S_DIRSYNC)))
1662 #define IS_MANDLOCK(inode)      __IS_FLG(inode, MS_MANDLOCK)
1663 #define IS_NOATIME(inode)       __IS_FLG(inode, MS_RDONLY|MS_NOATIME)
1664 #define IS_I_VERSION(inode)     __IS_FLG(inode, MS_I_VERSION)
1665 
1666 #define IS_NOQUOTA(inode)       ((inode)->i_flags & S_NOQUOTA)
1667 #define IS_APPEND(inode)        ((inode)->i_flags & S_APPEND)
1668 #define IS_IMMUTABLE(inode)     ((inode)->i_flags & S_IMMUTABLE)
1669 #define IS_POSIXACL(inode)      __IS_FLG(inode, MS_POSIXACL)
1670 
1671 #define IS_DEADDIR(inode)       ((inode)->i_flags & S_DEAD)
1672 #define IS_NOCMTIME(inode)      ((inode)->i_flags & S_NOCMTIME)
1673 #define IS_SWAPFILE(inode)      ((inode)->i_flags & S_SWAPFILE)
1674 #define IS_PRIVATE(inode)       ((inode)->i_flags & S_PRIVATE)
1675 #define IS_IMA(inode)           ((inode)->i_flags & S_IMA)
1676 #define IS_AUTOMOUNT(inode)     ((inode)->i_flags & S_AUTOMOUNT)
1677 #define IS_NOSEC(inode)         ((inode)->i_flags & S_NOSEC)
1678 
1679 #define IS_WHITEOUT(inode)      (S_ISCHR(inode->i_mode) && \
1680                                  (inode)->i_rdev == WHITEOUT_DEV)
1681 
1682 /*
1683  * Inode state bits.  Protected by inode->i_lock
1684  *
1685  * Three bits determine the dirty state of the inode, I_DIRTY_SYNC,
1686  * I_DIRTY_DATASYNC and I_DIRTY_PAGES.
1687  *
1688  * Four bits define the lifetime of an inode.  Initially, inodes are I_NEW,
1689  * until that flag is cleared.  I_WILL_FREE, I_FREEING and I_CLEAR are set at
1690  * various stages of removing an inode.
1691  *
1692  * Two bits are used for locking and completion notification, I_NEW and I_SYNC.
1693  *
1694  * I_DIRTY_SYNC         Inode is dirty, but doesn't have to be written on
1695  *                      fdatasync().  i_atime is the usual cause.
1696  * I_DIRTY_DATASYNC     Data-related inode changes pending. We keep track of
1697  *                      these changes separately from I_DIRTY_SYNC so that we
1698  *                      don't have to write inode on fdatasync() when only
1699  *                      mtime has changed in it.
1700  * I_DIRTY_PAGES        Inode has dirty pages.  Inode itself may be clean.
1701  * I_NEW                Serves as both a mutex and completion notification.
1702  *                      New inodes set I_NEW.  If two processes both create
1703  *                      the same inode, one of them will release its inode and
1704  *                      wait for I_NEW to be released before returning.
1705  *                      Inodes in I_WILL_FREE, I_FREEING or I_CLEAR state can
1706  *                      also cause waiting on I_NEW, without I_NEW actually
1707  *                      being set.  find_inode() uses this to prevent returning
1708  *                      nearly-dead inodes.
1709  * I_WILL_FREE          Must be set when calling write_inode_now() if i_count
1710  *                      is zero.  I_FREEING must be set when I_WILL_FREE is
1711  *                      cleared.
1712  * I_FREEING            Set when inode is about to be freed but still has dirty
1713  *                      pages or buffers attached or the inode itself is still
1714  *                      dirty.
1715  * I_CLEAR              Added by clear_inode().  In this state the inode is
1716  *                      clean and can be destroyed.  Inode keeps I_FREEING.
1717  *
1718  *                      Inodes that are I_WILL_FREE, I_FREEING or I_CLEAR are
1719  *                      prohibited for many purposes.  iget() must wait for
1720  *                      the inode to be completely released, then create it
1721  *                      anew.  Other functions will just ignore such inodes,
1722  *                      if appropriate.  I_NEW is used for waiting.
1723  *
1724  * I_SYNC               Writeback of inode is running. The bit is set during
1725  *                      data writeback, and cleared with a wakeup on the bit
1726  *                      address once it is done. The bit is also used to pin
1727  *                      the inode in memory for flusher thread.
1728  *
1729  * I_REFERENCED         Marks the inode as recently references on the LRU list.
1730  *
1731  * I_DIO_WAKEUP         Never set.  Only used as a key for wait_on_bit().
1732  *
1733  * Q: What is the difference between I_WILL_FREE and I_FREEING?
1734  */
1735 #define I_DIRTY_SYNC            (1 << 0)
1736 #define I_DIRTY_DATASYNC        (1 << 1)
1737 #define I_DIRTY_PAGES           (1 << 2)
1738 #define __I_NEW                 3
1739 #define I_NEW                   (1 << __I_NEW)
1740 #define I_WILL_FREE             (1 << 4)
1741 #define I_FREEING               (1 << 5)
1742 #define I_CLEAR                 (1 << 6)
1743 #define __I_SYNC                7
1744 #define I_SYNC                  (1 << __I_SYNC)
1745 #define I_REFERENCED            (1 << 8)
1746 #define __I_DIO_WAKEUP          9
1747 #define I_DIO_WAKEUP            (1 << I_DIO_WAKEUP)
1748 #define I_LINKABLE              (1 << 10)
1749 
1750 #define I_DIRTY (I_DIRTY_SYNC | I_DIRTY_DATASYNC | I_DIRTY_PAGES)
1751 
1752 extern void __mark_inode_dirty(struct inode *, int);
1753 static inline void mark_inode_dirty(struct inode *inode)
1754 {
1755         __mark_inode_dirty(inode, I_DIRTY);
1756 }
1757 
1758 static inline void mark_inode_dirty_sync(struct inode *inode)
1759 {
1760         __mark_inode_dirty(inode, I_DIRTY_SYNC);
1761 }
1762 
1763 extern void inc_nlink(struct inode *inode);
1764 extern void drop_nlink(struct inode *inode);
1765 extern void clear_nlink(struct inode *inode);
1766 extern void set_nlink(struct inode *inode, unsigned int nlink);
1767 
1768 static inline void inode_inc_link_count(struct inode *inode)
1769 {
1770         inc_nlink(inode);
1771         mark_inode_dirty(inode);
1772 }
1773 
1774 static inline void inode_dec_link_count(struct inode *inode)
1775 {
1776         drop_nlink(inode);
1777         mark_inode_dirty(inode);
1778 }
1779 
1780 /**
1781  * inode_inc_iversion - increments i_version
1782  * @inode: inode that need to be updated
1783  *
1784  * Every time the inode is modified, the i_version field will be incremented.
1785  * The filesystem has to be mounted with i_version flag
1786  */
1787 
1788 static inline void inode_inc_iversion(struct inode *inode)
1789 {
1790        spin_lock(&inode->i_lock);
1791        inode->i_version++;
1792        spin_unlock(&inode->i_lock);
1793 }
1794 
1795 enum file_time_flags {
1796         S_ATIME = 1,
1797         S_MTIME = 2,
1798         S_CTIME = 4,
1799         S_VERSION = 8,
1800 };
1801 
1802 extern void touch_atime(const struct path *);
1803 static inline void file_accessed(struct file *file)
1804 {
1805         if (!(file->f_flags & O_NOATIME))
1806                 touch_atime(&file->f_path);
1807 }
1808 
1809 int sync_inode(struct inode *inode, struct writeback_control *wbc);
1810 int sync_inode_metadata(struct inode *inode, int wait);
1811 
1812 struct file_system_type {
1813         const char *name;
1814         int fs_flags;
1815 #define FS_REQUIRES_DEV         1 
1816 #define FS_BINARY_MOUNTDATA     2
1817 #define FS_HAS_SUBTYPE          4
1818 #define FS_USERNS_MOUNT         8       /* Can be mounted by userns root */
1819 #define FS_USERNS_DEV_MOUNT     16 /* A userns mount does not imply MNT_NODEV */
1820 #define FS_RENAME_DOES_D_MOVE   32768   /* FS will handle d_move() during rename() internally. */
1821         struct dentry *(*mount) (struct file_system_type *, int,
1822                        const char *, void *);
1823         void (*kill_sb) (struct super_block *);
1824         struct module *owner;
1825         struct file_system_type * next;
1826         struct hlist_head fs_supers;
1827 
1828         struct lock_class_key s_lock_key;
1829         struct lock_class_key s_umount_key;
1830         struct lock_class_key s_vfs_rename_key;
1831         struct lock_class_key s_writers_key[SB_FREEZE_LEVELS];
1832 
1833         struct lock_class_key i_lock_key;
1834         struct lock_class_key i_mutex_key;
1835         struct lock_class_key i_mutex_dir_key;
1836 };
1837 
1838 #define MODULE_ALIAS_FS(NAME) MODULE_ALIAS("fs-" NAME)
1839 
1840 extern struct dentry *mount_ns(struct file_system_type *fs_type, int flags,
1841         void *data, int (*fill_super)(struct super_block *, void *, int));
1842 extern struct dentry *mount_bdev(struct file_system_type *fs_type,
1843         int flags, const char *dev_name, void *data,
1844         int (*fill_super)(struct super_block *, void *, int));
1845 extern struct dentry *mount_single(struct file_system_type *fs_type,
1846         int flags, void *data,
1847         int (*fill_super)(struct super_block *, void *, int));
1848 extern struct dentry *mount_nodev(struct file_system_type *fs_type,
1849         int flags, void *data,
1850         int (*fill_super)(struct super_block *, void *, int));
1851 extern struct dentry *mount_subtree(struct vfsmount *mnt, const char *path);
1852 void generic_shutdown_super(struct super_block *sb);
1853 void kill_block_super(struct super_block *sb);
1854 void kill_anon_super(struct super_block *sb);
1855 void kill_litter_super(struct super_block *sb);
1856 void deactivate_super(struct super_block *sb);
1857 void deactivate_locked_super(struct super_block *sb);
1858 int set_anon_super(struct super_block *s, void *data);
1859 int get_anon_bdev(dev_t *);
1860 void free_anon_bdev(dev_t);
1861 struct super_block *sget(struct file_system_type *type,
1862                         int (*test)(struct super_block *,void *),
1863                         int (*set)(struct super_block *,void *),
1864                         int flags, void *data);
1865 extern struct dentry *mount_pseudo(struct file_system_type *, char *,
1866         const struct super_operations *ops,
1867         const struct dentry_operations *dops,
1868         unsigned long);
1869 
1870 /* Alas, no aliases. Too much hassle with bringing module.h everywhere */
1871 #define fops_get(fops) \
1872         (((fops) && try_module_get((fops)->owner) ? (fops) : NULL))
1873 #define fops_put(fops) \
1874         do { if (fops) module_put((fops)->owner); } while(0)
1875 /*
1876  * This one is to be used *ONLY* from ->open() instances.
1877  * fops must be non-NULL, pinned down *and* module dependencies
1878  * should be sufficient to pin the caller down as well.
1879  */
1880 #define replace_fops(f, fops) \
1881         do {    \
1882                 struct file *__file = (f); \
1883                 fops_put(__file->f_op); \
1884                 BUG_ON(!(__file->f_op = (fops))); \
1885         } while(0)
1886 
1887 extern int register_filesystem(struct file_system_type *);
1888 extern int unregister_filesystem(struct file_system_type *);
1889 extern struct vfsmount *kern_mount_data(struct file_system_type *, void *data);
1890 #define kern_mount(type) kern_mount_data(type, NULL)
1891 extern void kern_unmount(struct vfsmount *mnt);
1892 extern int may_umount_tree(struct vfsmount *);
1893 extern int may_umount(struct vfsmount *);
1894 extern long do_mount(const char *, const char __user *,
1895                      const char *, unsigned long, void *);
1896 extern struct vfsmount *collect_mounts(struct path *);
1897 extern void drop_collected_mounts(struct vfsmount *);
1898 extern int iterate_mounts(int (*)(struct vfsmount *, void *), void *,
1899                           struct vfsmount *);
1900 extern int vfs_statfs(struct path *, struct kstatfs *);
1901 extern int user_statfs(const char __user *, struct kstatfs *);
1902 extern int fd_statfs(int, struct kstatfs *);
1903 extern int vfs_ustat(dev_t, struct kstatfs *);
1904 extern int freeze_super(struct super_block *super);
1905 extern int thaw_super(struct super_block *super);
1906 extern bool our_mnt(struct vfsmount *mnt);
1907 extern bool fs_fully_visible(struct file_system_type *);
1908 
1909 extern int current_umask(void);
1910 
1911 extern void ihold(struct inode * inode);
1912 extern void iput(struct inode *);
1913 
1914 static inline struct inode *file_inode(const struct file *f)
1915 {
1916         return f->f_inode;
1917 }
1918 
1919 /* /sys/fs */
1920 extern struct kobject *fs_kobj;
1921 
1922 #define MAX_RW_COUNT (INT_MAX & PAGE_CACHE_MASK)
1923 
1924 #define FLOCK_VERIFY_READ  1
1925 #define FLOCK_VERIFY_WRITE 2
1926 
1927 #ifdef CONFIG_FILE_LOCKING
1928 extern int locks_mandatory_locked(struct file *);
1929 extern int locks_mandatory_area(int, struct inode *, struct file *, loff_t, size_t);
1930 
1931 /*
1932  * Candidates for mandatory locking have the setgid bit set
1933  * but no group execute bit -  an otherwise meaningless combination.
1934  */
1935 
1936 static inline int __mandatory_lock(struct inode *ino)
1937 {
1938         return (ino->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID;
1939 }
1940 
1941 /*
1942  * ... and these candidates should be on MS_MANDLOCK mounted fs,
1943  * otherwise these will be advisory locks
1944  */
1945 
1946 static inline int mandatory_lock(struct inode *ino)
1947 {
1948         return IS_MANDLOCK(ino) && __mandatory_lock(ino);
1949 }
1950 
1951 static inline int locks_verify_locked(struct file *file)
1952 {
1953         if (mandatory_lock(file_inode(file)))
1954                 return locks_mandatory_locked(file);
1955         return 0;
1956 }
1957 
1958 static inline int locks_verify_truncate(struct inode *inode,
1959                                     struct file *filp,
1960                                     loff_t size)
1961 {
1962         if (inode->i_flock && mandatory_lock(inode))
1963                 return locks_mandatory_area(
1964                         FLOCK_VERIFY_WRITE, inode, filp,
1965                         size < inode->i_size ? size : inode->i_size,
1966                         (size < inode->i_size ? inode->i_size - size
1967                          : size - inode->i_size)
1968                 );
1969         return 0;
1970 }
1971 
1972 static inline int break_lease(struct inode *inode, unsigned int mode)
1973 {
1974         /*
1975          * Since this check is lockless, we must ensure that any refcounts
1976          * taken are done before checking inode->i_flock. Otherwise, we could
1977          * end up racing with tasks trying to set a new lease on this file.
1978          */
1979         smp_mb();
1980         if (inode->i_flock)
1981                 return __break_lease(inode, mode, FL_LEASE);
1982         return 0;
1983 }
1984 
1985 static inline int break_deleg(struct inode *inode, unsigned int mode)
1986 {
1987         /*
1988          * Since this check is lockless, we must ensure that any refcounts
1989          * taken are done before checking inode->i_flock. Otherwise, we could
1990          * end up racing with tasks trying to set a new lease on this file.
1991          */
1992         smp_mb();
1993         if (inode->i_flock)
1994                 return __break_lease(inode, mode, FL_DELEG);
1995         return 0;
1996 }
1997 
1998 static inline int try_break_deleg(struct inode *inode, struct inode **delegated_inode)
1999 {
2000         int ret;
2001 
2002         ret = break_deleg(inode, O_WRONLY|O_NONBLOCK);
2003         if (ret == -EWOULDBLOCK && delegated_inode) {
2004                 *delegated_inode = inode;
2005                 ihold(inode);
2006         }
2007         return ret;
2008 }
2009 
2010 static inline int break_deleg_wait(struct inode **delegated_inode)
2011 {
2012         int ret;
2013 
2014         ret = break_deleg(*delegated_inode, O_WRONLY);
2015         iput(*delegated_inode);
2016         *delegated_inode = NULL;
2017         return ret;
2018 }
2019 
2020 #else /* !CONFIG_FILE_LOCKING */
2021 static inline int locks_mandatory_locked(struct file *file)
2022 {
2023         return 0;
2024 }
2025 
2026 static inline int locks_mandatory_area(int rw, struct inode *inode,
2027                                        struct file *filp, loff_t offset,
2028                                        size_t count)
2029 {
2030         return 0;
2031 }
2032 
2033 static inline int __mandatory_lock(struct inode *inode)
2034 {
2035         return 0;
2036 }
2037 
2038 static inline int mandatory_lock(struct inode *inode)
2039 {
2040         return 0;
2041 }
2042 
2043 static inline int locks_verify_locked(struct file *file)
2044 {
2045         return 0;
2046 }
2047 
2048 static inline int locks_verify_truncate(struct inode *inode, struct file *filp,
2049                                         size_t size)
2050 {
2051         return 0;
2052 }
2053 
2054 static inline int break_lease(struct inode *inode, unsigned int mode)
2055 {
2056         return 0;
2057 }
2058 
2059 static inline int break_deleg(struct inode *inode, unsigned int mode)
2060 {
2061         return 0;
2062 }
2063 
2064 static inline int try_break_deleg(struct inode *inode, struct inode **delegated_inode)
2065 {
2066         return 0;
2067 }
2068 
2069 static inline int break_deleg_wait(struct inode **delegated_inode)
2070 {
2071         BUG();
2072         return 0;
2073 }
2074 
2075 #endif /* CONFIG_FILE_LOCKING */
2076 
2077 /* fs/open.c */
2078 struct audit_names;
2079 struct filename {
2080         const char              *name;  /* pointer to actual string */
2081         const __user char       *uptr;  /* original userland pointer */
2082         struct audit_names      *aname;
2083         bool                    separate; /* should "name" be freed? */
2084 };
2085 
2086 extern long vfs_truncate(struct path *, loff_t);
2087 extern int do_truncate(struct dentry *, loff_t start, unsigned int time_attrs,
2088                        struct file *filp);
2089 extern int vfs_fallocate(struct file *file, int mode, loff_t offset,
2090                         loff_t len);
2091 extern long do_sys_open(int dfd, const char __user *filename, int flags,
2092                         umode_t mode);
2093 extern struct file *file_open_name(struct filename *, int, umode_t);
2094 extern struct file *filp_open(const char *, int, umode_t);
2095 extern struct file *file_open_root(struct dentry *, struct vfsmount *,
2096                                    const char *, int);
2097 extern int vfs_open(const struct path *, struct file *, const struct cred *);
2098 extern struct file * dentry_open(const struct path *, int, const struct cred *);
2099 extern int filp_close(struct file *, fl_owner_t id);
2100 
2101 extern struct filename *getname_flags(const char __user *, int, int *);
2102 extern struct filename *getname(const char __user *);
2103 extern struct filename *getname_kernel(const char *);
2104 
2105 enum {
2106         FILE_CREATED = 1,
2107         FILE_OPENED = 2
2108 };
2109 extern int finish_open(struct file *file, struct dentry *dentry,
2110                         int (*open)(struct inode *, struct file *),
2111                         int *opened);
2112 extern int finish_no_open(struct file *file, struct dentry *dentry);
2113 
2114 /* fs/ioctl.c */
2115 
2116 extern int ioctl_preallocate(struct file *filp, void __user *argp);
2117 
2118 /* fs/dcache.c */
2119 extern void __init vfs_caches_init_early(void);
2120 extern void __init vfs_caches_init(unsigned long);
2121 
2122 extern struct kmem_cache *names_cachep;
2123 
2124 extern void final_putname(struct filename *name);
2125 
2126 #define __getname()             kmem_cache_alloc(names_cachep, GFP_KERNEL)
2127 #define __putname(name)         kmem_cache_free(names_cachep, (void *)(name))
2128 #ifndef CONFIG_AUDITSYSCALL
2129 #define putname(name)           final_putname(name)
2130 #else
2131 extern void putname(struct filename *name);
2132 #endif
2133 
2134 #ifdef CONFIG_BLOCK
2135 extern int register_blkdev(unsigned int, const char *);
2136 extern void unregister_blkdev(unsigned int, const char *);
2137 extern struct block_device *bdget(dev_t);
2138 extern struct block_device *bdgrab(struct block_device *bdev);
2139 extern void bd_set_size(struct block_device *, loff_t size);
2140 extern void bd_forget(struct inode *inode);
2141 extern void bdput(struct block_device *);
2142 extern void invalidate_bdev(struct block_device *);
2143 extern void iterate_bdevs(void (*)(struct block_device *, void *), void *);
2144 extern int sync_blockdev(struct block_device *bdev);
2145 extern void kill_bdev(struct block_device *);
2146 extern struct super_block *freeze_bdev(struct block_device *);
2147 extern void emergency_thaw_all(void);
2148 extern int thaw_bdev(struct block_device *bdev, struct super_block *sb);
2149 extern int fsync_bdev(struct block_device *);
2150 extern int sb_is_blkdev_sb(struct super_block *sb);
2151 #else
2152 static inline void bd_forget(struct inode *inode) {}
2153 static inline int sync_blockdev(struct block_device *bdev) { return 0; }
2154 static inline void kill_bdev(struct block_device *bdev) {}
2155 static inline void invalidate_bdev(struct block_device *bdev) {}
2156 
2157 static inline struct super_block *freeze_bdev(struct block_device *sb)
2158 {
2159         return NULL;
2160 }
2161 
2162 static inline int thaw_bdev(struct block_device *bdev, struct super_block *sb)
2163 {
2164         return 0;
2165 }
2166 
2167 static inline void iterate_bdevs(void (*f)(struct block_device *, void *), void *arg)
2168 {
2169 }
2170 
2171 static inline int sb_is_blkdev_sb(struct super_block *sb)
2172 {
2173         return 0;
2174 }
2175 #endif
2176 extern int sync_filesystem(struct super_block *);
2177 extern const struct file_operations def_blk_fops;
2178 extern const struct file_operations def_chr_fops;
2179 #ifdef CONFIG_BLOCK
2180 extern int ioctl_by_bdev(struct block_device *, unsigned, unsigned long);
2181 extern int blkdev_ioctl(struct block_device *, fmode_t, unsigned, unsigned long);
2182 extern long compat_blkdev_ioctl(struct file *, unsigned, unsigned long);
2183 extern int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder);
2184 extern struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
2185                                                void *holder);
2186 extern struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode,
2187                                               void *holder);
2188 extern void blkdev_put(struct block_device *bdev, fmode_t mode);
2189 #ifdef CONFIG_SYSFS
2190 extern int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk);
2191 extern void bd_unlink_disk_holder(struct block_device *bdev,
2192                                   struct gendisk *disk);
2193 #else
2194 static inline int bd_link_disk_holder(struct block_device *bdev,
2195                                       struct gendisk *disk)
2196 {
2197         return 0;
2198 }
2199 static inline void bd_unlink_disk_holder(struct block_device *bdev,
2200                                          struct gendisk *disk)
2201 {
2202 }
2203 #endif
2204 #endif
2205 
2206 /* fs/char_dev.c */
2207 #define CHRDEV_MAJOR_HASH_SIZE  255
2208 extern int alloc_chrdev_region(dev_t *, unsigned, unsigned, const char *);
2209 extern int register_chrdev_region(dev_t, unsigned, const char *);
2210 extern int __register_chrdev(unsigned int major, unsigned int baseminor,
2211                              unsigned int count, const char *name,
2212                              const struct file_operations *fops);
2213 extern void __unregister_chrdev(unsigned int major, unsigned int baseminor,
2214                                 unsigned int count, const char *name);
2215 extern void unregister_chrdev_region(dev_t, unsigned);
2216 extern void chrdev_show(struct seq_file *,off_t);
2217 
2218 static inline int register_chrdev(unsigned int major, const char *name,
2219                                   const struct file_operations *fops)
2220 {
2221         return __register_chrdev(major, 0, 256, name, fops);
2222 }
2223 
2224 static inline void unregister_chrdev(unsigned int major, const char *name)
2225 {
2226         __unregister_chrdev(major, 0, 256, name);
2227 }
2228 
2229 /* fs/block_dev.c */
2230 #define BDEVNAME_SIZE   32      /* Largest string for a blockdev identifier */
2231 #define BDEVT_SIZE      10      /* Largest string for MAJ:MIN for blkdev */
2232 
2233 #ifdef CONFIG_BLOCK
2234 #define BLKDEV_MAJOR_HASH_SIZE  255
2235 extern const char *__bdevname(dev_t, char *buffer);
2236 extern const char *bdevname(struct block_device *bdev, char *buffer);
2237 extern struct block_device *lookup_bdev(const char *);
2238 extern void blkdev_show(struct seq_file *,off_t);
2239 
2240 #else
2241 #define BLKDEV_MAJOR_HASH_SIZE  0
2242 #endif
2243 
2244 extern void init_special_inode(struct inode *, umode_t, dev_t);
2245 
2246 /* Invalid inode operations -- fs/bad_inode.c */
2247 extern void make_bad_inode(struct inode *);
2248 extern int is_bad_inode(struct inode *);
2249 
2250 #ifdef CONFIG_BLOCK
2251 /*
2252  * return READ, READA, or WRITE
2253  */
2254 #define bio_rw(bio)             ((bio)->bi_rw & (RW_MASK | RWA_MASK))
2255 
2256 /*
2257  * return data direction, READ or WRITE
2258  */
2259 #define bio_data_dir(bio)       ((bio)->bi_rw & 1)
2260 
2261 extern void check_disk_size_change(struct gendisk *disk,
2262                                    struct block_device *bdev);
2263 extern int revalidate_disk(struct gendisk *);
2264 extern int check_disk_change(struct block_device *);
2265 extern int __invalidate_device(struct block_device *, bool);
2266 extern int invalidate_partition(struct gendisk *, int);
2267 #endif
2268 unsigned long invalidate_mapping_pages(struct address_space *mapping,
2269                                         pgoff_t start, pgoff_t end);
2270 
2271 static inline void invalidate_remote_inode(struct inode *inode)
2272 {
2273         if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
2274             S_ISLNK(inode->i_mode))
2275                 invalidate_mapping_pages(inode->i_mapping, 0, -1);
2276 }
2277 extern int invalidate_inode_pages2(struct address_space *mapping);
2278 extern int invalidate_inode_pages2_range(struct address_space *mapping,
2279                                          pgoff_t start, pgoff_t end);
2280 extern int write_inode_now(struct inode *, int);
2281 extern int filemap_fdatawrite(struct address_space *);
2282 extern int filemap_flush(struct address_space *);
2283 extern int filemap_fdatawait(struct address_space *);
2284 extern int filemap_fdatawait_range(struct address_space *, loff_t lstart,
2285                                    loff_t lend);
2286 extern int filemap_write_and_wait(struct address_space *mapping);
2287 extern int filemap_write_and_wait_range(struct address_space *mapping,
2288                                         loff_t lstart, loff_t lend);
2289 extern int __filemap_fdatawrite_range(struct address_space *mapping,
2290                                 loff_t start, loff_t end, int sync_mode);
2291 extern int filemap_fdatawrite_range(struct address_space *mapping,
2292                                 loff_t start, loff_t end);
2293 
2294 extern int vfs_fsync_range(struct file *file, loff_t start, loff_t end,
2295                            int datasync);
2296 extern int vfs_fsync(struct file *file, int datasync);
2297 static inline int generic_write_sync(struct file *file, loff_t pos, loff_t count)
2298 {
2299         if (!(file->f_flags & O_DSYNC) && !IS_SYNC(file->f_mapping->host))
2300                 return 0;
2301         return vfs_fsync_range(file, pos, pos + count - 1,
2302                                (file->f_flags & __O_SYNC) ? 0 : 1);
2303 }
2304 extern void emergency_sync(void);
2305 extern void emergency_remount(void);
2306 #ifdef CONFIG_BLOCK
2307 extern sector_t bmap(struct inode *, sector_t);
2308 #endif
2309 extern int notify_change(struct dentry *, struct iattr *, struct inode **);
2310 extern int inode_permission(struct inode *, int);
2311 extern int __inode_permission(struct inode *, int);
2312 extern int generic_permission(struct inode *, int);
2313 extern int __check_sticky(struct inode *dir, struct inode *inode);
2314 
2315 static inline bool execute_ok(struct inode *inode)
2316 {
2317         return (inode->i_mode & S_IXUGO) || S_ISDIR(inode->i_mode);
2318 }
2319 
2320 static inline void file_start_write(struct file *file)
2321 {
2322         if (!S_ISREG(file_inode(file)->i_mode))
2323                 return;
2324         __sb_start_write(file_inode(file)->i_sb, SB_FREEZE_WRITE, true);
2325 }
2326 
2327 static inline bool file_start_write_trylock(struct file *file)
2328 {
2329         if (!S_ISREG(file_inode(file)->i_mode))
2330                 return true;
2331         return __sb_start_write(file_inode(file)->i_sb, SB_FREEZE_WRITE, false);
2332 }
2333 
2334 static inline void file_end_write(struct file *file)
2335 {
2336         if (!S_ISREG(file_inode(file)->i_mode))
2337                 return;
2338         __sb_end_write(file_inode(file)->i_sb, SB_FREEZE_WRITE);
2339 }
2340 
2341 /*
2342  * get_write_access() gets write permission for a file.
2343  * put_write_access() releases this write permission.
2344  * This is used for regular files.
2345  * We cannot support write (and maybe mmap read-write shared) accesses and
2346  * MAP_DENYWRITE mmappings simultaneously. The i_writecount field of an inode
2347  * can have the following values:
2348  * 0: no writers, no VM_DENYWRITE mappings
2349  * < 0: (-i_writecount) vm_area_structs with VM_DENYWRITE set exist
2350  * > 0: (i_writecount) users are writing to the file.
2351  *
2352  * Normally we operate on that counter with atomic_{inc,dec} and it's safe
2353  * except for the cases where we don't hold i_writecount yet. Then we need to
2354  * use {get,deny}_write_access() - these functions check the sign and refuse
2355  * to do the change if sign is wrong.
2356  */
2357 static inline int get_write_access(struct inode *inode)
2358 {
2359         return atomic_inc_unless_negative(&inode->i_writecount) ? 0 : -ETXTBSY;
2360 }
2361 static inline int deny_write_access(struct file *file)
2362 {
2363         struct inode *inode = file_inode(file);
2364         return atomic_dec_unless_positive(&inode->i_writecount) ? 0 : -ETXTBSY;
2365 }
2366 static inline void put_write_access(struct inode * inode)
2367 {
2368         atomic_dec(&inode->i_writecount);
2369 }
2370 static inline void allow_write_access(struct file *file)
2371 {
2372         if (file)
2373                 atomic_inc(&file_inode(file)->i_writecount);
2374 }
2375 static inline bool inode_is_open_for_write(const struct inode *inode)
2376 {
2377         return atomic_read(&inode->i_writecount) > 0;
2378 }
2379 
2380 #ifdef CONFIG_IMA
2381 static inline void i_readcount_dec(struct inode *inode)
2382 {
2383         BUG_ON(!atomic_read(&inode->i_readcount));
2384         atomic_dec(&inode->i_readcount);
2385 }
2386 static inline void i_readcount_inc(struct inode *inode)
2387 {
2388         atomic_inc(&inode->i_readcount);
2389 }
2390 #else
2391 static inline void i_readcount_dec(struct inode *inode)
2392 {
2393         return;
2394 }
2395 static inline void i_readcount_inc(struct inode *inode)
2396 {
2397         return;
2398 }
2399 #endif
2400 extern int do_pipe_flags(int *, int);
2401 
2402 extern int kernel_read(struct file *, loff_t, char *, unsigned long);
2403 extern ssize_t kernel_write(struct file *, const char *, size_t, loff_t);
2404 extern ssize_t __kernel_write(struct file *, const char *, size_t, loff_t *);
2405 extern struct file * open_exec(const char *);
2406  
2407 /* fs/dcache.c -- generic fs support functions */
2408 extern int is_subdir(struct dentry *, struct dentry *);
2409 extern int path_is_under(struct path *, struct path *);
2410 
2411 #include <linux/err.h>
2412 
2413 /* needed for stackable file system support */
2414 extern loff_t default_llseek(struct file *file, loff_t offset, int whence);
2415 
2416 extern loff_t vfs_llseek(struct file *file, loff_t offset, int whence);
2417 
2418 extern int inode_init_always(struct super_block *, struct inode *);
2419 extern void inode_init_once(struct inode *);
2420 extern void address_space_init_once(struct address_space *mapping);
2421 extern struct inode * igrab(struct inode *);
2422 extern ino_t iunique(struct super_block *, ino_t);
2423 extern int inode_needs_sync(struct inode *inode);
2424 extern int generic_delete_inode(struct inode *inode);
2425 static inline int generic_drop_inode(struct inode *inode)
2426 {
2427         return !inode->i_nlink || inode_unhashed(inode);
2428 }
2429 
2430 extern struct inode *ilookup5_nowait(struct super_block *sb,
2431                 unsigned long hashval, int (*test)(struct inode *, void *),
2432                 void *data);
2433 extern struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
2434                 int (*test)(struct inode *, void *), void *data);
2435 extern struct inode *ilookup(struct super_block *sb, unsigned long ino);
2436 
2437 extern struct inode * iget5_locked(struct super_block *, unsigned long, int (*test)(struct inode *, void *), int (*set)(struct inode *, void *), void *);
2438 extern struct inode * iget_locked(struct super_block *, unsigned long);
2439 extern int insert_inode_locked4(struct inode *, unsigned long, int (*test)(struct inode *, void *), void *);
2440 extern int insert_inode_locked(struct inode *);
2441 #ifdef CONFIG_DEBUG_LOCK_ALLOC
2442 extern void lockdep_annotate_inode_mutex_key(struct inode *inode);
2443 #else
2444 static inline void lockdep_annotate_inode_mutex_key(struct inode *inode) { };
2445 #endif
2446 extern void unlock_new_inode(struct inode *);
2447 extern unsigned int get_next_ino(void);
2448 
2449 extern void __iget(struct inode * inode);
2450 extern void iget_failed(struct inode *);
2451 extern void clear_inode(struct inode *);
2452 extern void __destroy_inode(struct inode *);
2453 extern struct inode *new_inode_pseudo(struct super_block *sb);
2454 extern struct inode *new_inode(struct super_block *sb);
2455 extern void free_inode_nonrcu(struct inode *inode);
2456 extern int should_remove_suid(struct dentry *);
2457 extern int file_remove_suid(struct file *);
2458 
2459 extern void __insert_inode_hash(struct inode *, unsigned long hashval);
2460 static inline void insert_inode_hash(struct inode *inode)
2461 {
2462         __insert_inode_hash(inode, inode->i_ino);
2463 }
2464 
2465 extern void __remove_inode_hash(struct inode *);
2466 static inline void remove_inode_hash(struct inode *inode)
2467 {
2468         if (!inode_unhashed(inode))
2469                 __remove_inode_hash(inode);
2470 }
2471 
2472 extern void inode_sb_list_add(struct inode *inode);
2473 
2474 #ifdef CONFIG_BLOCK
2475 extern void submit_bio(int, struct bio *);
2476 extern int bdev_read_only(struct block_device *);
2477 #endif
2478 extern int set_blocksize(struct block_device *, int);
2479 extern int sb_set_blocksize(struct super_block *, int);
2480 extern int sb_min_blocksize(struct super_block *, int);
2481 
2482 extern int generic_file_mmap(struct file *, struct vm_area_struct *);
2483 extern int generic_file_readonly_mmap(struct file *, struct vm_area_struct *);
2484 extern int generic_file_remap_pages(struct vm_area_struct *, unsigned long addr,
2485                 unsigned long size, pgoff_t pgoff);
2486 int generic_write_checks(struct file *file, loff_t *pos, size_t *count, int isblk);
2487 extern ssize_t generic_file_read_iter(struct kiocb *, struct iov_iter *);
2488 extern ssize_t __generic_file_write_iter(struct kiocb *, struct iov_iter *);
2489 extern ssize_t generic_file_write_iter(struct kiocb *, struct iov_iter *);
2490 extern ssize_t generic_file_direct_write(struct kiocb *, struct iov_iter *, loff_t);
2491 extern ssize_t generic_perform_write(struct file *, struct iov_iter *, loff_t);
2492 extern ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos);
2493 extern ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos);
2494 extern ssize_t new_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos);
2495 extern ssize_t new_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos);
2496 
2497 /* fs/block_dev.c */
2498 extern ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to);
2499 extern ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from);
2500 extern int blkdev_fsync(struct file *filp, loff_t start, loff_t end,
2501                         int datasync);
2502 extern void block_sync_page(struct page *page);
2503 
2504 /* fs/splice.c */
2505 extern ssize_t generic_file_splice_read(struct file *, loff_t *,
2506                 struct pipe_inode_info *, size_t, unsigned int);
2507 extern ssize_t default_file_splice_read(struct file *, loff_t *,
2508                 struct pipe_inode_info *, size_t, unsigned int);
2509 extern ssize_t iter_file_splice_write(struct pipe_inode_info *,
2510                 struct file *, loff_t *, size_t, unsigned int);
2511 extern ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe,
2512                 struct file *out, loff_t *, size_t len, unsigned int flags);
2513 extern long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
2514                 loff_t *opos, size_t len, unsigned int flags);
2515 
2516 
2517 extern void
2518 file_ra_state_init(struct file_ra_state *ra, struct address_space *mapping);
2519 extern loff_t noop_llseek(struct file *file, loff_t offset, int whence);
2520 extern loff_t no_llseek(struct file *file, loff_t offset, int whence);
2521 extern loff_t vfs_setpos(struct file *file, loff_t offset, loff_t maxsize);
2522 extern loff_t generic_file_llseek(struct file *file, loff_t offset, int whence);
2523 extern loff_t generic_file_llseek_size(struct file *file, loff_t offset,
2524                 int whence, loff_t maxsize, loff_t eof);
2525 extern loff_t fixed_size_llseek(struct file *file, loff_t offset,
2526                 int whence, loff_t size);
2527 extern int generic_file_open(struct inode * inode, struct file * filp);
2528 extern int nonseekable_open(struct inode * inode, struct file * filp);
2529 
2530 #ifdef CONFIG_FS_XIP
2531 extern ssize_t xip_file_read(struct file *filp, char __user *buf, size_t len,
2532                              loff_t *ppos);
2533 extern int xip_file_mmap(struct file * file, struct vm_area_struct * vma);
2534 extern ssize_t xip_file_write(struct file *filp, const char __user *buf,
2535                               size_t len, loff_t *ppos);
2536 extern int xip_truncate_page(struct address_space *mapping, loff_t from);
2537 #else
2538 static inline int xip_truncate_page(struct address_space *mapping, loff_t from)
2539 {
2540         return 0;
2541 }
2542 #endif
2543 
2544 #ifdef CONFIG_BLOCK
2545 typedef void (dio_submit_t)(int rw, struct bio *bio, struct inode *inode,
2546                             loff_t file_offset);
2547 
2548 enum {
2549         /* need locking between buffered and direct access */
2550         DIO_LOCKING     = 0x01,
2551 
2552         /* filesystem does not support filling holes */
2553         DIO_SKIP_HOLES  = 0x02,
2554 
2555         /* filesystem can handle aio writes beyond i_size */
2556         DIO_ASYNC_EXTEND = 0x04,
2557 };
2558 
2559 void dio_end_io(struct bio *bio, int error);
2560 
2561 ssize_t __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
2562         struct block_device *bdev, struct iov_iter *iter, loff_t offset,
2563         get_block_t get_block, dio_iodone_t end_io,
2564         dio_submit_t submit_io, int flags);
2565 
2566 static inline ssize_t blockdev_direct_IO(int rw, struct kiocb *iocb,
2567                 struct inode *inode, struct iov_iter *iter, loff_t offset,
2568                 get_block_t get_block)
2569 {
2570         return __blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iter,
2571                                     offset, get_block, NULL, NULL,
2572                                     DIO_LOCKING | DIO_SKIP_HOLES);
2573 }
2574 #endif
2575 
2576 void inode_dio_wait(struct inode *inode);
2577 void inode_dio_done(struct inode *inode);
2578 
2579 extern void inode_set_flags(struct inode *inode, unsigned int flags,
2580                             unsigned int mask);
2581 
2582 extern const struct file_operations generic_ro_fops;
2583 
2584 #define special_file(m) (S_ISCHR(m)||S_ISBLK(m)||S_ISFIFO(m)||S_ISSOCK(m))
2585 
2586 extern int readlink_copy(char __user *, int, const char *);
2587 extern int page_readlink(struct dentry *, char __user *, int);
2588 extern void *page_follow_link_light(struct dentry *, struct nameidata *);
2589 extern void page_put_link(struct dentry *, struct nameidata *, void *);
2590 extern int __page_symlink(struct inode *inode, const char *symname, int len,
2591                 int nofs);
2592 extern int page_symlink(struct inode *inode, const char *symname, int len);
2593 extern const struct inode_operations page_symlink_inode_operations;
2594 extern void kfree_put_link(struct dentry *, struct nameidata *, void *);
2595 extern int generic_readlink(struct dentry *, char __user *, int);
2596 extern void generic_fillattr(struct inode *, struct kstat *);
2597 int vfs_getattr_nosec(struct path *path, struct kstat *stat);
2598 extern int vfs_getattr(struct path *, struct kstat *);
2599 void __inode_add_bytes(struct inode *inode, loff_t bytes);
2600 void inode_add_bytes(struct inode *inode, loff_t bytes);
2601 void __inode_sub_bytes(struct inode *inode, loff_t bytes);
2602 void inode_sub_bytes(struct inode *inode, loff_t bytes);
2603 loff_t inode_get_bytes(struct inode *inode);
2604 void inode_set_bytes(struct inode *inode, loff_t bytes);
2605 
2606 extern int vfs_readdir(struct file *, filldir_t, void *);
2607 extern int iterate_dir(struct file *, struct dir_context *);
2608 
2609 extern int vfs_stat(const char __user *, struct kstat *);
2610 extern int vfs_lstat(const char __user *, struct kstat *);
2611 extern int vfs_fstat(unsigned int, struct kstat *);
2612 extern int vfs_fstatat(int , const char __user *, struct kstat *, int);
2613 
2614 extern int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd,
2615                     unsigned long arg);
2616 extern int __generic_block_fiemap(struct inode *inode,
2617                                   struct fiemap_extent_info *fieinfo,
2618                                   loff_t start, loff_t len,
2619                                   get_block_t *get_block);
2620 extern int generic_block_fiemap(struct inode *inode,
2621                                 struct fiemap_extent_info *fieinfo, u64 start,
2622                                 u64 len, get_block_t *get_block);
2623 
2624 extern void get_filesystem(struct file_system_type *fs);
2625 extern void put_filesystem(struct file_system_type *fs);
2626 extern struct file_system_type *get_fs_type(const char *name);
2627 extern struct super_block *get_super(struct block_device *);
2628 extern struct super_block *get_super_thawed(struct block_device *);
2629 extern struct super_block *get_active_super(struct block_device *bdev);
2630 extern void drop_super(struct super_block *sb);
2631 extern void iterate_supers(void (*)(struct super_block *, void *), void *);
2632 extern void iterate_supers_type(struct file_system_type *,
2633                                 void (*)(struct super_block *, void *), void *);
2634 
2635 extern int dcache_dir_open(struct inode *, struct file *);
2636 extern int dcache_dir_close(struct inode *, struct file *);
2637 extern loff_t dcache_dir_lseek(struct file *, loff_t, int);
2638 extern int dcache_readdir(struct file *, struct dir_context *);
2639 extern int simple_setattr(struct dentry *, struct iattr *);
2640 extern int simple_getattr(struct vfsmount *, struct dentry *, struct kstat *);
2641 extern int simple_statfs(struct dentry *, struct kstatfs *);
2642 extern int simple_open(struct inode *inode, struct file *file);
2643 extern int simple_link(struct dentry *, struct inode *, struct dentry *);
2644 extern int simple_unlink(struct inode *, struct dentry *);
2645 extern int simple_rmdir(struct inode *, struct dentry *);
2646 extern int simple_rename(struct inode *, struct dentry *, struct inode *, struct dentry *);
2647 extern int noop_fsync(struct file *, loff_t, loff_t, int);
2648 extern int simple_empty(struct dentry *);
2649 extern int simple_readpage(struct file *file, struct page *page);
2650 extern int simple_write_begin(struct file *file, struct address_space *mapping,
2651                         loff_t pos, unsigned len, unsigned flags,
2652                         struct page **pagep, void **fsdata);
2653 extern int simple_write_end(struct file *file, struct address_space *mapping,
2654                         loff_t pos, unsigned len, unsigned copied,
2655                         struct page *page, void *fsdata);
2656 extern int always_delete_dentry(const struct dentry *);
2657 extern struct inode *alloc_anon_inode(struct super_block *);
2658 extern int simple_nosetlease(struct file *, long, struct file_lock **, void **);
2659 extern const struct dentry_operations simple_dentry_operations;
2660 
2661 extern struct dentry *simple_lookup(struct inode *, struct dentry *, unsigned int flags);
2662 extern ssize_t generic_read_dir(struct file *, char __user *, size_t, loff_t *);
2663 extern const struct file_operations simple_dir_operations;
2664 extern const struct inode_operations simple_dir_inode_operations;
2665 struct tree_descr { char *name; const struct file_operations *ops; int mode; };
2666 struct dentry *d_alloc_name(struct dentry *, const char *);
2667 extern int simple_fill_super(struct super_block *, unsigned long, struct tree_descr *);
2668 extern int simple_pin_fs(struct file_system_type *, struct vfsmount **mount, int *count);
2669 extern void simple_release_fs(struct vfsmount **mount, int *count);
2670 
2671 extern ssize_t simple_read_from_buffer(void __user *to, size_t count,
2672                         loff_t *ppos, const void *from, size_t available);
2673 extern ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos,
2674                 const void __user *from, size_t count);
2675 
2676 extern int __generic_file_fsync(struct file *, loff_t, loff_t, int);
2677 extern int generic_file_fsync(struct file *, loff_t, loff_t, int);
2678 
2679 extern int generic_check_addressable(unsigned, u64);
2680 
2681 #ifdef CONFIG_MIGRATION
2682 extern int buffer_migrate_page(struct address_space *,
2683                                 struct page *, struct page *,
2684                                 enum migrate_mode);
2685 #else
2686 #define buffer_migrate_page NULL
2687 #endif
2688 
2689 extern int inode_change_ok(const struct inode *, struct iattr *);
2690 extern int inode_newsize_ok(const struct inode *, loff_t offset);
2691 extern void setattr_copy(struct inode *inode, const struct iattr *attr);
2692 
2693 extern int file_update_time(struct file *file);
2694 
2695 extern int generic_show_options(struct seq_file *m, struct dentry *root);
2696 extern void save_mount_options(struct super_block *sb, char *options);
2697 extern void replace_mount_options(struct super_block *sb, char *options);
2698 
2699 static inline ino_t parent_ino(struct dentry *dentry)
2700 {
2701         ino_t res;
2702 
2703         /*
2704          * Don't strictly need d_lock here? If the parent ino could change
2705          * then surely we'd have a deeper race in the caller?
2706          */
2707         spin_lock(&dentry->d_lock);
2708         res = dentry->d_parent->d_inode->i_ino;
2709         spin_unlock(&dentry->d_lock);
2710         return res;
2711 }
2712 
2713 /* Transaction based IO helpers */
2714 
2715 /*
2716  * An argresp is stored in an allocated page and holds the
2717  * size of the argument or response, along with its content
2718  */
2719 struct simple_transaction_argresp {
2720         ssize_t size;
2721         char data[0];
2722 };
2723 
2724 #define SIMPLE_TRANSACTION_LIMIT (PAGE_SIZE - sizeof(struct simple_transaction_argresp))
2725 
2726 char *simple_transaction_get(struct file *file, const char __user *buf,
2727                                 size_t size);
2728 ssize_t simple_transaction_read(struct file *file, char __user *buf,
2729                                 size_t size, loff_t *pos);
2730 int simple_transaction_release(struct inode *inode, struct file *file);
2731 
2732 void simple_transaction_set(struct file *file, size_t n);
2733 
2734 /*
2735  * simple attribute files
2736  *
2737  * These attributes behave similar to those in sysfs:
2738  *
2739  * Writing to an attribute immediately sets a value, an open file can be
2740  * written to multiple times.
2741  *
2742  * Reading from an attribute creates a buffer from the value that might get
2743  * read with multiple read calls. When the attribute has been read
2744  * completely, no further read calls are possible until the file is opened
2745  * again.
2746  *
2747  * All attributes contain a text representation of a numeric value
2748  * that are accessed with the get() and set() functions.
2749  */
2750 #define DEFINE_SIMPLE_ATTRIBUTE(__fops, __get, __set, __fmt)            \
2751 static int __fops ## _open(struct inode *inode, struct file *file)      \
2752 {                                                                       \
2753         __simple_attr_check_format(__fmt, 0ull);                        \
2754         return simple_attr_open(inode, file, __get, __set, __fmt);      \
2755 }                                                                       \
2756 static const struct file_operations __fops = {                          \
2757         .owner   = THIS_MODULE,                                         \
2758         .open    = __fops ## _open,                                     \
2759         .release = simple_attr_release,                                 \
2760         .read    = simple_attr_read,                                    \
2761         .write   = simple_attr_write,                                   \
2762         .llseek  = generic_file_llseek,                                 \
2763 }
2764 
2765 static inline __printf(1, 2)
2766 void __simple_attr_check_format(const char *fmt, ...)
2767 {
2768         /* don't do anything, just let the compiler check the arguments; */
2769 }
2770 
2771 int simple_attr_open(struct inode *inode, struct file *file,
2772                      int (*get)(void *, u64 *), int (*set)(void *, u64),
2773                      const char *fmt);
2774 int simple_attr_release(struct inode *inode, struct file *file);
2775 ssize_t simple_attr_read(struct file *file, char __user *buf,
2776                          size_t len, loff_t *ppos);
2777 ssize_t simple_attr_write(struct file *file, const char __user *buf,
2778                           size_t len, loff_t *ppos);
2779 
2780 struct ctl_table;
2781 int proc_nr_files(struct ctl_table *table, int write,
2782                   void __user *buffer, size_t *lenp, loff_t *ppos);
2783 int proc_nr_dentry(struct ctl_table *table, int write,
2784                   void __user *buffer, size_t *lenp, loff_t *ppos);
2785 int proc_nr_inodes(struct ctl_table *table, int write,
2786                    void __user *buffer, size_t *lenp, loff_t *ppos);
2787 int __init get_filesystem_list(char *buf);
2788 
2789 #define __FMODE_EXEC            ((__force int) FMODE_EXEC)
2790 #define __FMODE_NONOTIFY        ((__force int) FMODE_NONOTIFY)
2791 
2792 #define ACC_MODE(x) ("\004\002\006\006"[(x)&O_ACCMODE])
2793 #define OPEN_FMODE(flag) ((__force fmode_t)(((flag + 1) & O_ACCMODE) | \
2794                                             (flag & __FMODE_NONOTIFY)))
2795 
2796 static inline int is_sxid(umode_t mode)
2797 {
2798         return (mode & S_ISUID) || ((mode & S_ISGID) && (mode & S_IXGRP));
2799 }
2800 
2801 static inline int check_sticky(struct inode *dir, struct inode *inode)
2802 {
2803         if (!(dir->i_mode & S_ISVTX))
2804                 return 0;
2805 
2806         return __check_sticky(dir, inode);
2807 }
2808 
2809 static inline void inode_has_no_xattr(struct inode *inode)
2810 {
2811         if (!is_sxid(inode->i_mode) && (inode->i_sb->s_flags & MS_NOSEC))
2812                 inode->i_flags |= S_NOSEC;
2813 }
2814 
2815 static inline bool is_root_inode(struct inode *inode)
2816 {
2817         return inode == inode->i_sb->s_root->d_inode;
2818 }
2819 
2820 static inline bool dir_emit(struct dir_context *ctx,
2821                             const char *name, int namelen,
2822                             u64 ino, unsigned type)
2823 {
2824         return ctx->actor(ctx, name, namelen, ctx->pos, ino, type) == 0;
2825 }
2826 static inline bool dir_emit_dot(struct file *file, struct dir_context *ctx)
2827 {
2828         return ctx->actor(ctx, ".", 1, ctx->pos,
2829                           file->f_path.dentry->d_inode->i_ino, DT_DIR) == 0;
2830 }
2831 static inline bool dir_emit_dotdot(struct file *file, struct dir_context *ctx)
2832 {
2833         return ctx->actor(ctx, "..", 2, ctx->pos,
2834                           parent_ino(file->f_path.dentry), DT_DIR) == 0;
2835 }
2836 static inline bool dir_emit_dots(struct file *file, struct dir_context *ctx)
2837 {
2838         if (ctx->pos == 0) {
2839                 if (!dir_emit_dot(file, ctx))
2840                         return false;
2841                 ctx->pos = 1;
2842         }
2843         if (ctx->pos == 1) {
2844                 if (!dir_emit_dotdot(file, ctx))
2845                         return false;
2846                 ctx->pos = 2;
2847         }
2848         return true;
2849 }
2850 static inline bool dir_relax(struct inode *inode)
2851 {
2852         mutex_unlock(&inode->i_mutex);
2853         mutex_lock(&inode->i_mutex);
2854         return !IS_DEADDIR(inode);
2855 }
2856 
2857 #endif /* _LINUX_FS_H */
2858 

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