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

Version: ~ [ linux-5.12-rc7 ] ~ [ linux-5.11.13 ] ~ [ linux-5.10.29 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.111 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.186 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.230 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.266 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.266 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.18.140 ] ~ [ linux-3.16.85 ] ~ [ linux-3.14.79 ] ~ [ linux-3.12.74 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
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  1 #ifndef _LINUX_FS_H
  2 #define _LINUX_FS_H
  3 
  4 #include <linux/linkage.h>
  5 #include <linux/wait_bit.h>
  6 #include <linux/kdev_t.h>
  7 #include <linux/dcache.h>
  8 #include <linux/path.h>
  9 #include <linux/stat.h>
 10 #include <linux/cache.h>
 11 #include <linux/list.h>
 12 #include <linux/list_lru.h>
 13 #include <linux/llist.h>
 14 #include <linux/radix-tree.h>
 15 #include <linux/rbtree.h>
 16 #include <linux/init.h>
 17 #include <linux/pid.h>
 18 #include <linux/bug.h>
 19 #include <linux/mutex.h>
 20 #include <linux/rwsem.h>
 21 #include <linux/mm_types.h>
 22 #include <linux/capability.h>
 23 #include <linux/semaphore.h>
 24 #include <linux/fcntl.h>
 25 #include <linux/fiemap.h>
 26 #include <linux/rculist_bl.h>
 27 #include <linux/atomic.h>
 28 #include <linux/shrinker.h>
 29 #include <linux/migrate_mode.h>
 30 #include <linux/uidgid.h>
 31 #include <linux/lockdep.h>
 32 #include <linux/percpu-rwsem.h>
 33 #include <linux/workqueue.h>
 34 #include <linux/delayed_call.h>
 35 #include <linux/uuid.h>
 36 #include <linux/errseq.h>
 37 
 38 #include <asm/byteorder.h>
 39 #include <uapi/linux/fs.h>
 40 
 41 struct backing_dev_info;
 42 struct bdi_writeback;
 43 struct bio;
 44 struct export_operations;
 45 struct hd_geometry;
 46 struct iovec;
 47 struct kiocb;
 48 struct kobject;
 49 struct pipe_inode_info;
 50 struct poll_table_struct;
 51 struct kstatfs;
 52 struct vm_area_struct;
 53 struct vfsmount;
 54 struct cred;
 55 struct swap_info_struct;
 56 struct seq_file;
 57 struct workqueue_struct;
 58 struct iov_iter;
 59 struct fscrypt_info;
 60 struct fscrypt_operations;
 61 
 62 extern void __init inode_init(void);
 63 extern void __init inode_init_early(void);
 64 extern void __init files_init(void);
 65 extern void __init files_maxfiles_init(void);
 66 
 67 extern struct files_stat_struct files_stat;
 68 extern unsigned long get_max_files(void);
 69 extern unsigned int sysctl_nr_open;
 70 extern struct inodes_stat_t inodes_stat;
 71 extern int leases_enable, lease_break_time;
 72 extern int sysctl_protected_symlinks;
 73 extern int sysctl_protected_hardlinks;
 74 
 75 struct buffer_head;
 76 typedef int (get_block_t)(struct inode *inode, sector_t iblock,
 77                         struct buffer_head *bh_result, int create);
 78 typedef int (dio_iodone_t)(struct kiocb *iocb, loff_t offset,
 79                         ssize_t bytes, void *private);
 80 
 81 #define MAY_EXEC                0x00000001
 82 #define MAY_WRITE               0x00000002
 83 #define MAY_READ                0x00000004
 84 #define MAY_APPEND              0x00000008
 85 #define MAY_ACCESS              0x00000010
 86 #define MAY_OPEN                0x00000020
 87 #define MAY_CHDIR               0x00000040
 88 /* called from RCU mode, don't block */
 89 #define MAY_NOT_BLOCK           0x00000080
 90 
 91 /*
 92  * flags in file.f_mode.  Note that FMODE_READ and FMODE_WRITE must correspond
 93  * to O_WRONLY and O_RDWR via the strange trick in __dentry_open()
 94  */
 95 
 96 /* file is open for reading */
 97 #define FMODE_READ              ((__force fmode_t)0x1)
 98 /* file is open for writing */
 99 #define FMODE_WRITE             ((__force fmode_t)0x2)
100 /* file is seekable */
101 #define FMODE_LSEEK             ((__force fmode_t)0x4)
102 /* file can be accessed using pread */
103 #define FMODE_PREAD             ((__force fmode_t)0x8)
104 /* file can be accessed using pwrite */
105 #define FMODE_PWRITE            ((__force fmode_t)0x10)
106 /* File is opened for execution with sys_execve / sys_uselib */
107 #define FMODE_EXEC              ((__force fmode_t)0x20)
108 /* File is opened with O_NDELAY (only set for block devices) */
109 #define FMODE_NDELAY            ((__force fmode_t)0x40)
110 /* File is opened with O_EXCL (only set for block devices) */
111 #define FMODE_EXCL              ((__force fmode_t)0x80)
112 /* File is opened using open(.., 3, ..) and is writeable only for ioctls
113    (specialy hack for floppy.c) */
114 #define FMODE_WRITE_IOCTL       ((__force fmode_t)0x100)
115 /* 32bit hashes as llseek() offset (for directories) */
116 #define FMODE_32BITHASH         ((__force fmode_t)0x200)
117 /* 64bit hashes as llseek() offset (for directories) */
118 #define FMODE_64BITHASH         ((__force fmode_t)0x400)
119 
120 /*
121  * Don't update ctime and mtime.
122  *
123  * Currently a special hack for the XFS open_by_handle ioctl, but we'll
124  * hopefully graduate it to a proper O_CMTIME flag supported by open(2) soon.
125  */
126 #define FMODE_NOCMTIME          ((__force fmode_t)0x800)
127 
128 /* Expect random access pattern */
129 #define FMODE_RANDOM            ((__force fmode_t)0x1000)
130 
131 /* File is huge (eg. /dev/kmem): treat loff_t as unsigned */
132 #define FMODE_UNSIGNED_OFFSET   ((__force fmode_t)0x2000)
133 
134 /* File is opened with O_PATH; almost nothing can be done with it */
135 #define FMODE_PATH              ((__force fmode_t)0x4000)
136 
137 /* File needs atomic accesses to f_pos */
138 #define FMODE_ATOMIC_POS        ((__force fmode_t)0x8000)
139 /* Write access to underlying fs */
140 #define FMODE_WRITER            ((__force fmode_t)0x10000)
141 /* Has read method(s) */
142 #define FMODE_CAN_READ          ((__force fmode_t)0x20000)
143 /* Has write method(s) */
144 #define FMODE_CAN_WRITE         ((__force fmode_t)0x40000)
145 
146 /* File was opened by fanotify and shouldn't generate fanotify events */
147 #define FMODE_NONOTIFY          ((__force fmode_t)0x4000000)
148 
149 /* File is capable of returning -EAGAIN if AIO will block */
150 #define FMODE_AIO_NOWAIT        ((__force fmode_t)0x8000000)
151 
152 /*
153  * Flag for rw_copy_check_uvector and compat_rw_copy_check_uvector
154  * that indicates that they should check the contents of the iovec are
155  * valid, but not check the memory that the iovec elements
156  * points too.
157  */
158 #define CHECK_IOVEC_ONLY -1
159 
160 /*
161  * Attribute flags.  These should be or-ed together to figure out what
162  * has been changed!
163  */
164 #define ATTR_MODE       (1 << 0)
165 #define ATTR_UID        (1 << 1)
166 #define ATTR_GID        (1 << 2)
167 #define ATTR_SIZE       (1 << 3)
168 #define ATTR_ATIME      (1 << 4)
169 #define ATTR_MTIME      (1 << 5)
170 #define ATTR_CTIME      (1 << 6)
171 #define ATTR_ATIME_SET  (1 << 7)
172 #define ATTR_MTIME_SET  (1 << 8)
173 #define ATTR_FORCE      (1 << 9) /* Not a change, but a change it */
174 #define ATTR_ATTR_FLAG  (1 << 10)
175 #define ATTR_KILL_SUID  (1 << 11)
176 #define ATTR_KILL_SGID  (1 << 12)
177 #define ATTR_FILE       (1 << 13)
178 #define ATTR_KILL_PRIV  (1 << 14)
179 #define ATTR_OPEN       (1 << 15) /* Truncating from open(O_TRUNC) */
180 #define ATTR_TIMES_SET  (1 << 16)
181 #define ATTR_TOUCH      (1 << 17)
182 
183 /*
184  * Whiteout is represented by a char device.  The following constants define the
185  * mode and device number to use.
186  */
187 #define WHITEOUT_MODE 0
188 #define WHITEOUT_DEV 0
189 
190 /*
191  * This is the Inode Attributes structure, used for notify_change().  It
192  * uses the above definitions as flags, to know which values have changed.
193  * Also, in this manner, a Filesystem can look at only the values it cares
194  * about.  Basically, these are the attributes that the VFS layer can
195  * request to change from the FS layer.
196  *
197  * Derek Atkins <warlord@MIT.EDU> 94-10-20
198  */
199 struct iattr {
200         unsigned int    ia_valid;
201         umode_t         ia_mode;
202         kuid_t          ia_uid;
203         kgid_t          ia_gid;
204         loff_t          ia_size;
205         struct timespec ia_atime;
206         struct timespec ia_mtime;
207         struct timespec ia_ctime;
208 
209         /*
210          * Not an attribute, but an auxiliary info for filesystems wanting to
211          * implement an ftruncate() like method.  NOTE: filesystem should
212          * check for (ia_valid & ATTR_FILE), and not for (ia_file != NULL).
213          */
214         struct file     *ia_file;
215 };
216 
217 /*
218  * Includes for diskquotas.
219  */
220 #include <linux/quota.h>
221 
222 /*
223  * Maximum number of layers of fs stack.  Needs to be limited to
224  * prevent kernel stack overflow
225  */
226 #define FILESYSTEM_MAX_STACK_DEPTH 2
227 
228 /** 
229  * enum positive_aop_returns - aop return codes with specific semantics
230  *
231  * @AOP_WRITEPAGE_ACTIVATE: Informs the caller that page writeback has
232  *                          completed, that the page is still locked, and
233  *                          should be considered active.  The VM uses this hint
234  *                          to return the page to the active list -- it won't
235  *                          be a candidate for writeback again in the near
236  *                          future.  Other callers must be careful to unlock
237  *                          the page if they get this return.  Returned by
238  *                          writepage(); 
239  *
240  * @AOP_TRUNCATED_PAGE: The AOP method that was handed a locked page has
241  *                      unlocked it and the page might have been truncated.
242  *                      The caller should back up to acquiring a new page and
243  *                      trying again.  The aop will be taking reasonable
244  *                      precautions not to livelock.  If the caller held a page
245  *                      reference, it should drop it before retrying.  Returned
246  *                      by readpage().
247  *
248  * address_space_operation functions return these large constants to indicate
249  * special semantics to the caller.  These are much larger than the bytes in a
250  * page to allow for functions that return the number of bytes operated on in a
251  * given page.
252  */
253 
254 enum positive_aop_returns {
255         AOP_WRITEPAGE_ACTIVATE  = 0x80000,
256         AOP_TRUNCATED_PAGE      = 0x80001,
257 };
258 
259 #define AOP_FLAG_CONT_EXPAND            0x0001 /* called from cont_expand */
260 #define AOP_FLAG_NOFS                   0x0002 /* used by filesystem to direct
261                                                 * helper code (eg buffer layer)
262                                                 * to clear GFP_FS from alloc */
263 
264 /*
265  * oh the beauties of C type declarations.
266  */
267 struct page;
268 struct address_space;
269 struct writeback_control;
270 
271 /*
272  * Write life time hint values.
273  */
274 enum rw_hint {
275         WRITE_LIFE_NOT_SET      = 0,
276         WRITE_LIFE_NONE         = RWH_WRITE_LIFE_NONE,
277         WRITE_LIFE_SHORT        = RWH_WRITE_LIFE_SHORT,
278         WRITE_LIFE_MEDIUM       = RWH_WRITE_LIFE_MEDIUM,
279         WRITE_LIFE_LONG         = RWH_WRITE_LIFE_LONG,
280         WRITE_LIFE_EXTREME      = RWH_WRITE_LIFE_EXTREME,
281 };
282 
283 #define IOCB_EVENTFD            (1 << 0)
284 #define IOCB_APPEND             (1 << 1)
285 #define IOCB_DIRECT             (1 << 2)
286 #define IOCB_HIPRI              (1 << 3)
287 #define IOCB_DSYNC              (1 << 4)
288 #define IOCB_SYNC               (1 << 5)
289 #define IOCB_WRITE              (1 << 6)
290 #define IOCB_NOWAIT             (1 << 7)
291 
292 struct kiocb {
293         struct file             *ki_filp;
294         loff_t                  ki_pos;
295         void (*ki_complete)(struct kiocb *iocb, long ret, long ret2);
296         void                    *private;
297         int                     ki_flags;
298         enum rw_hint            ki_hint;
299 } __randomize_layout;
300 
301 static inline bool is_sync_kiocb(struct kiocb *kiocb)
302 {
303         return kiocb->ki_complete == NULL;
304 }
305 
306 /*
307  * "descriptor" for what we're up to with a read.
308  * This allows us to use the same read code yet
309  * have multiple different users of the data that
310  * we read from a file.
311  *
312  * The simplest case just copies the data to user
313  * mode.
314  */
315 typedef struct {
316         size_t written;
317         size_t count;
318         union {
319                 char __user *buf;
320                 void *data;
321         } arg;
322         int error;
323 } read_descriptor_t;
324 
325 typedef int (*read_actor_t)(read_descriptor_t *, struct page *,
326                 unsigned long, unsigned long);
327 
328 struct address_space_operations {
329         int (*writepage)(struct page *page, struct writeback_control *wbc);
330         int (*readpage)(struct file *, struct page *);
331 
332         /* Write back some dirty pages from this mapping. */
333         int (*writepages)(struct address_space *, struct writeback_control *);
334 
335         /* Set a page dirty.  Return true if this dirtied it */
336         int (*set_page_dirty)(struct page *page);
337 
338         int (*readpages)(struct file *filp, struct address_space *mapping,
339                         struct list_head *pages, unsigned nr_pages);
340 
341         int (*write_begin)(struct file *, struct address_space *mapping,
342                                 loff_t pos, unsigned len, unsigned flags,
343                                 struct page **pagep, void **fsdata);
344         int (*write_end)(struct file *, struct address_space *mapping,
345                                 loff_t pos, unsigned len, unsigned copied,
346                                 struct page *page, void *fsdata);
347 
348         /* Unfortunately this kludge is needed for FIBMAP. Don't use it */
349         sector_t (*bmap)(struct address_space *, sector_t);
350         void (*invalidatepage) (struct page *, unsigned int, unsigned int);
351         int (*releasepage) (struct page *, gfp_t);
352         void (*freepage)(struct page *);
353         ssize_t (*direct_IO)(struct kiocb *, struct iov_iter *iter);
354         /*
355          * migrate the contents of a page to the specified target. If
356          * migrate_mode is MIGRATE_ASYNC, it must not block.
357          */
358         int (*migratepage) (struct address_space *,
359                         struct page *, struct page *, enum migrate_mode);
360         bool (*isolate_page)(struct page *, isolate_mode_t);
361         void (*putback_page)(struct page *);
362         int (*launder_page) (struct page *);
363         int (*is_partially_uptodate) (struct page *, unsigned long,
364                                         unsigned long);
365         void (*is_dirty_writeback) (struct page *, bool *, bool *);
366         int (*error_remove_page)(struct address_space *, struct page *);
367 
368         /* swapfile support */
369         int (*swap_activate)(struct swap_info_struct *sis, struct file *file,
370                                 sector_t *span);
371         void (*swap_deactivate)(struct file *file);
372 };
373 
374 extern const struct address_space_operations empty_aops;
375 
376 /*
377  * pagecache_write_begin/pagecache_write_end must be used by general code
378  * to write into the pagecache.
379  */
380 int pagecache_write_begin(struct file *, struct address_space *mapping,
381                                 loff_t pos, unsigned len, unsigned flags,
382                                 struct page **pagep, void **fsdata);
383 
384 int pagecache_write_end(struct file *, struct address_space *mapping,
385                                 loff_t pos, unsigned len, unsigned copied,
386                                 struct page *page, void *fsdata);
387 
388 struct address_space {
389         struct inode            *host;          /* owner: inode, block_device */
390         struct radix_tree_root  page_tree;      /* radix tree of all pages */
391         spinlock_t              tree_lock;      /* and lock protecting it */
392         atomic_t                i_mmap_writable;/* count VM_SHARED mappings */
393         struct rb_root          i_mmap;         /* tree of private and shared mappings */
394         struct rw_semaphore     i_mmap_rwsem;   /* protect tree, count, list */
395         /* Protected by tree_lock together with the radix tree */
396         unsigned long           nrpages;        /* number of total pages */
397         /* number of shadow or DAX exceptional entries */
398         unsigned long           nrexceptional;
399         pgoff_t                 writeback_index;/* writeback starts here */
400         const struct address_space_operations *a_ops;   /* methods */
401         unsigned long           flags;          /* error bits */
402         spinlock_t              private_lock;   /* for use by the address_space */
403         gfp_t                   gfp_mask;       /* implicit gfp mask for allocations */
404         struct list_head        private_list;   /* ditto */
405         void                    *private_data;  /* ditto */
406         errseq_t                wb_err;
407 } __attribute__((aligned(sizeof(long)))) __randomize_layout;
408         /*
409          * On most architectures that alignment is already the case; but
410          * must be enforced here for CRIS, to let the least significant bit
411          * of struct page's "mapping" pointer be used for PAGE_MAPPING_ANON.
412          */
413 struct request_queue;
414 
415 struct block_device {
416         dev_t                   bd_dev;  /* not a kdev_t - it's a search key */
417         int                     bd_openers;
418         struct inode *          bd_inode;       /* will die */
419         struct super_block *    bd_super;
420         struct mutex            bd_mutex;       /* open/close mutex */
421         void *                  bd_claiming;
422         void *                  bd_holder;
423         int                     bd_holders;
424         bool                    bd_write_holder;
425 #ifdef CONFIG_SYSFS
426         struct list_head        bd_holder_disks;
427 #endif
428         struct block_device *   bd_contains;
429         unsigned                bd_block_size;
430         struct hd_struct *      bd_part;
431         /* number of times partitions within this device have been opened. */
432         unsigned                bd_part_count;
433         int                     bd_invalidated;
434         struct gendisk *        bd_disk;
435         struct request_queue *  bd_queue;
436         struct backing_dev_info *bd_bdi;
437         struct list_head        bd_list;
438         /*
439          * Private data.  You must have bd_claim'ed the block_device
440          * to use this.  NOTE:  bd_claim allows an owner to claim
441          * the same device multiple times, the owner must take special
442          * care to not mess up bd_private for that case.
443          */
444         unsigned long           bd_private;
445 
446         /* The counter of freeze processes */
447         int                     bd_fsfreeze_count;
448         /* Mutex for freeze */
449         struct mutex            bd_fsfreeze_mutex;
450 } __randomize_layout;
451 
452 /*
453  * Radix-tree tags, for tagging dirty and writeback pages within the pagecache
454  * radix trees
455  */
456 #define PAGECACHE_TAG_DIRTY     0
457 #define PAGECACHE_TAG_WRITEBACK 1
458 #define PAGECACHE_TAG_TOWRITE   2
459 
460 int mapping_tagged(struct address_space *mapping, int tag);
461 
462 static inline void i_mmap_lock_write(struct address_space *mapping)
463 {
464         down_write(&mapping->i_mmap_rwsem);
465 }
466 
467 static inline void i_mmap_unlock_write(struct address_space *mapping)
468 {
469         up_write(&mapping->i_mmap_rwsem);
470 }
471 
472 static inline void i_mmap_lock_read(struct address_space *mapping)
473 {
474         down_read(&mapping->i_mmap_rwsem);
475 }
476 
477 static inline void i_mmap_unlock_read(struct address_space *mapping)
478 {
479         up_read(&mapping->i_mmap_rwsem);
480 }
481 
482 /*
483  * Might pages of this file be mapped into userspace?
484  */
485 static inline int mapping_mapped(struct address_space *mapping)
486 {
487         return  !RB_EMPTY_ROOT(&mapping->i_mmap);
488 }
489 
490 /*
491  * Might pages of this file have been modified in userspace?
492  * Note that i_mmap_writable counts all VM_SHARED vmas: do_mmap_pgoff
493  * marks vma as VM_SHARED if it is shared, and the file was opened for
494  * writing i.e. vma may be mprotected writable even if now readonly.
495  *
496  * If i_mmap_writable is negative, no new writable mappings are allowed. You
497  * can only deny writable mappings, if none exists right now.
498  */
499 static inline int mapping_writably_mapped(struct address_space *mapping)
500 {
501         return atomic_read(&mapping->i_mmap_writable) > 0;
502 }
503 
504 static inline int mapping_map_writable(struct address_space *mapping)
505 {
506         return atomic_inc_unless_negative(&mapping->i_mmap_writable) ?
507                 0 : -EPERM;
508 }
509 
510 static inline void mapping_unmap_writable(struct address_space *mapping)
511 {
512         atomic_dec(&mapping->i_mmap_writable);
513 }
514 
515 static inline int mapping_deny_writable(struct address_space *mapping)
516 {
517         return atomic_dec_unless_positive(&mapping->i_mmap_writable) ?
518                 0 : -EBUSY;
519 }
520 
521 static inline void mapping_allow_writable(struct address_space *mapping)
522 {
523         atomic_inc(&mapping->i_mmap_writable);
524 }
525 
526 /*
527  * Use sequence counter to get consistent i_size on 32-bit processors.
528  */
529 #if BITS_PER_LONG==32 && defined(CONFIG_SMP)
530 #include <linux/seqlock.h>
531 #define __NEED_I_SIZE_ORDERED
532 #define i_size_ordered_init(inode) seqcount_init(&inode->i_size_seqcount)
533 #else
534 #define i_size_ordered_init(inode) do { } while (0)
535 #endif
536 
537 struct posix_acl;
538 #define ACL_NOT_CACHED ((void *)(-1))
539 #define ACL_DONT_CACHE ((void *)(-3))
540 
541 static inline struct posix_acl *
542 uncached_acl_sentinel(struct task_struct *task)
543 {
544         return (void *)task + 1;
545 }
546 
547 static inline bool
548 is_uncached_acl(struct posix_acl *acl)
549 {
550         return (long)acl & 1;
551 }
552 
553 #define IOP_FASTPERM    0x0001
554 #define IOP_LOOKUP      0x0002
555 #define IOP_NOFOLLOW    0x0004
556 #define IOP_XATTR       0x0008
557 #define IOP_DEFAULT_READLINK    0x0010
558 
559 struct fsnotify_mark_connector;
560 
561 /*
562  * Keep mostly read-only and often accessed (especially for
563  * the RCU path lookup and 'stat' data) fields at the beginning
564  * of the 'struct inode'
565  */
566 struct inode {
567         umode_t                 i_mode;
568         unsigned short          i_opflags;
569         kuid_t                  i_uid;
570         kgid_t                  i_gid;
571         unsigned int            i_flags;
572 
573 #ifdef CONFIG_FS_POSIX_ACL
574         struct posix_acl        *i_acl;
575         struct posix_acl        *i_default_acl;
576 #endif
577 
578         const struct inode_operations   *i_op;
579         struct super_block      *i_sb;
580         struct address_space    *i_mapping;
581 
582 #ifdef CONFIG_SECURITY
583         void                    *i_security;
584 #endif
585 
586         /* Stat data, not accessed from path walking */
587         unsigned long           i_ino;
588         /*
589          * Filesystems may only read i_nlink directly.  They shall use the
590          * following functions for modification:
591          *
592          *    (set|clear|inc|drop)_nlink
593          *    inode_(inc|dec)_link_count
594          */
595         union {
596                 const unsigned int i_nlink;
597                 unsigned int __i_nlink;
598         };
599         dev_t                   i_rdev;
600         loff_t                  i_size;
601         struct timespec         i_atime;
602         struct timespec         i_mtime;
603         struct timespec         i_ctime;
604         spinlock_t              i_lock; /* i_blocks, i_bytes, maybe i_size */
605         unsigned short          i_bytes;
606         unsigned int            i_blkbits;
607         enum rw_hint            i_write_hint;
608         blkcnt_t                i_blocks;
609 
610 #ifdef __NEED_I_SIZE_ORDERED
611         seqcount_t              i_size_seqcount;
612 #endif
613 
614         /* Misc */
615         unsigned long           i_state;
616         struct rw_semaphore     i_rwsem;
617 
618         unsigned long           dirtied_when;   /* jiffies of first dirtying */
619         unsigned long           dirtied_time_when;
620 
621         struct hlist_node       i_hash;
622         struct list_head        i_io_list;      /* backing dev IO list */
623 #ifdef CONFIG_CGROUP_WRITEBACK
624         struct bdi_writeback    *i_wb;          /* the associated cgroup wb */
625 
626         /* foreign inode detection, see wbc_detach_inode() */
627         int                     i_wb_frn_winner;
628         u16                     i_wb_frn_avg_time;
629         u16                     i_wb_frn_history;
630 #endif
631         struct list_head        i_lru;          /* inode LRU list */
632         struct list_head        i_sb_list;
633         struct list_head        i_wb_list;      /* backing dev writeback list */
634         union {
635                 struct hlist_head       i_dentry;
636                 struct rcu_head         i_rcu;
637         };
638         u64                     i_version;
639         atomic_t                i_count;
640         atomic_t                i_dio_count;
641         atomic_t                i_writecount;
642 #ifdef CONFIG_IMA
643         atomic_t                i_readcount; /* struct files open RO */
644 #endif
645         const struct file_operations    *i_fop; /* former ->i_op->default_file_ops */
646         struct file_lock_context        *i_flctx;
647         struct address_space    i_data;
648         struct list_head        i_devices;
649         union {
650                 struct pipe_inode_info  *i_pipe;
651                 struct block_device     *i_bdev;
652                 struct cdev             *i_cdev;
653                 char                    *i_link;
654                 unsigned                i_dir_seq;
655         };
656 
657         __u32                   i_generation;
658 
659 #ifdef CONFIG_FSNOTIFY
660         __u32                   i_fsnotify_mask; /* all events this inode cares about */
661         struct fsnotify_mark_connector __rcu    *i_fsnotify_marks;
662 #endif
663 
664 #if IS_ENABLED(CONFIG_FS_ENCRYPTION)
665         struct fscrypt_info     *i_crypt_info;
666 #endif
667 
668         void                    *i_private; /* fs or device private pointer */
669 } __randomize_layout;
670 
671 static inline unsigned int i_blocksize(const struct inode *node)
672 {
673         return (1 << node->i_blkbits);
674 }
675 
676 static inline int inode_unhashed(struct inode *inode)
677 {
678         return hlist_unhashed(&inode->i_hash);
679 }
680 
681 /*
682  * inode->i_mutex nesting subclasses for the lock validator:
683  *
684  * 0: the object of the current VFS operation
685  * 1: parent
686  * 2: child/target
687  * 3: xattr
688  * 4: second non-directory
689  * 5: second parent (when locking independent directories in rename)
690  *
691  * I_MUTEX_NONDIR2 is for certain operations (such as rename) which lock two
692  * non-directories at once.
693  *
694  * The locking order between these classes is
695  * parent[2] -> child -> grandchild -> normal -> xattr -> second non-directory
696  */
697 enum inode_i_mutex_lock_class
698 {
699         I_MUTEX_NORMAL,
700         I_MUTEX_PARENT,
701         I_MUTEX_CHILD,
702         I_MUTEX_XATTR,
703         I_MUTEX_NONDIR2,
704         I_MUTEX_PARENT2,
705 };
706 
707 static inline void inode_lock(struct inode *inode)
708 {
709         down_write(&inode->i_rwsem);
710 }
711 
712 static inline void inode_unlock(struct inode *inode)
713 {
714         up_write(&inode->i_rwsem);
715 }
716 
717 static inline void inode_lock_shared(struct inode *inode)
718 {
719         down_read(&inode->i_rwsem);
720 }
721 
722 static inline void inode_unlock_shared(struct inode *inode)
723 {
724         up_read(&inode->i_rwsem);
725 }
726 
727 static inline int inode_trylock(struct inode *inode)
728 {
729         return down_write_trylock(&inode->i_rwsem);
730 }
731 
732 static inline int inode_trylock_shared(struct inode *inode)
733 {
734         return down_read_trylock(&inode->i_rwsem);
735 }
736 
737 static inline int inode_is_locked(struct inode *inode)
738 {
739         return rwsem_is_locked(&inode->i_rwsem);
740 }
741 
742 static inline void inode_lock_nested(struct inode *inode, unsigned subclass)
743 {
744         down_write_nested(&inode->i_rwsem, subclass);
745 }
746 
747 void lock_two_nondirectories(struct inode *, struct inode*);
748 void unlock_two_nondirectories(struct inode *, struct inode*);
749 
750 /*
751  * NOTE: in a 32bit arch with a preemptable kernel and
752  * an UP compile the i_size_read/write must be atomic
753  * with respect to the local cpu (unlike with preempt disabled),
754  * but they don't need to be atomic with respect to other cpus like in
755  * true SMP (so they need either to either locally disable irq around
756  * the read or for example on x86 they can be still implemented as a
757  * cmpxchg8b without the need of the lock prefix). For SMP compiles
758  * and 64bit archs it makes no difference if preempt is enabled or not.
759  */
760 static inline loff_t i_size_read(const struct inode *inode)
761 {
762 #if BITS_PER_LONG==32 && defined(CONFIG_SMP)
763         loff_t i_size;
764         unsigned int seq;
765 
766         do {
767                 seq = read_seqcount_begin(&inode->i_size_seqcount);
768                 i_size = inode->i_size;
769         } while (read_seqcount_retry(&inode->i_size_seqcount, seq));
770         return i_size;
771 #elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPT)
772         loff_t i_size;
773 
774         preempt_disable();
775         i_size = inode->i_size;
776         preempt_enable();
777         return i_size;
778 #else
779         return inode->i_size;
780 #endif
781 }
782 
783 /*
784  * NOTE: unlike i_size_read(), i_size_write() does need locking around it
785  * (normally i_mutex), otherwise on 32bit/SMP an update of i_size_seqcount
786  * can be lost, resulting in subsequent i_size_read() calls spinning forever.
787  */
788 static inline void i_size_write(struct inode *inode, loff_t i_size)
789 {
790 #if BITS_PER_LONG==32 && defined(CONFIG_SMP)
791         preempt_disable();
792         write_seqcount_begin(&inode->i_size_seqcount);
793         inode->i_size = i_size;
794         write_seqcount_end(&inode->i_size_seqcount);
795         preempt_enable();
796 #elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPT)
797         preempt_disable();
798         inode->i_size = i_size;
799         preempt_enable();
800 #else
801         inode->i_size = i_size;
802 #endif
803 }
804 
805 static inline unsigned iminor(const struct inode *inode)
806 {
807         return MINOR(inode->i_rdev);
808 }
809 
810 static inline unsigned imajor(const struct inode *inode)
811 {
812         return MAJOR(inode->i_rdev);
813 }
814 
815 extern struct block_device *I_BDEV(struct inode *inode);
816 
817 struct fown_struct {
818         rwlock_t lock;          /* protects pid, uid, euid fields */
819         struct pid *pid;        /* pid or -pgrp where SIGIO should be sent */
820         enum pid_type pid_type; /* Kind of process group SIGIO should be sent to */
821         kuid_t uid, euid;       /* uid/euid of process setting the owner */
822         int signum;             /* posix.1b rt signal to be delivered on IO */
823 };
824 
825 /*
826  * Track a single file's readahead state
827  */
828 struct file_ra_state {
829         pgoff_t start;                  /* where readahead started */
830         unsigned int size;              /* # of readahead pages */
831         unsigned int async_size;        /* do asynchronous readahead when
832                                            there are only # of pages ahead */
833 
834         unsigned int ra_pages;          /* Maximum readahead window */
835         unsigned int mmap_miss;         /* Cache miss stat for mmap accesses */
836         loff_t prev_pos;                /* Cache last read() position */
837 };
838 
839 /*
840  * Check if @index falls in the readahead windows.
841  */
842 static inline int ra_has_index(struct file_ra_state *ra, pgoff_t index)
843 {
844         return (index >= ra->start &&
845                 index <  ra->start + ra->size);
846 }
847 
848 struct file {
849         union {
850                 struct llist_node       fu_llist;
851                 struct rcu_head         fu_rcuhead;
852         } f_u;
853         struct path             f_path;
854         struct inode            *f_inode;       /* cached value */
855         const struct file_operations    *f_op;
856 
857         /*
858          * Protects f_ep_links, f_flags.
859          * Must not be taken from IRQ context.
860          */
861         spinlock_t              f_lock;
862         enum rw_hint            f_write_hint;
863         atomic_long_t           f_count;
864         unsigned int            f_flags;
865         fmode_t                 f_mode;
866         struct mutex            f_pos_lock;
867         loff_t                  f_pos;
868         struct fown_struct      f_owner;
869         const struct cred       *f_cred;
870         struct file_ra_state    f_ra;
871 
872         u64                     f_version;
873 #ifdef CONFIG_SECURITY
874         void                    *f_security;
875 #endif
876         /* needed for tty driver, and maybe others */
877         void                    *private_data;
878 
879 #ifdef CONFIG_EPOLL
880         /* Used by fs/eventpoll.c to link all the hooks to this file */
881         struct list_head        f_ep_links;
882         struct list_head        f_tfile_llink;
883 #endif /* #ifdef CONFIG_EPOLL */
884         struct address_space    *f_mapping;
885         errseq_t                f_wb_err;
886 } __randomize_layout
887   __attribute__((aligned(4)));  /* lest something weird decides that 2 is OK */
888 
889 struct file_handle {
890         __u32 handle_bytes;
891         int handle_type;
892         /* file identifier */
893         unsigned char f_handle[0];
894 };
895 
896 static inline struct file *get_file(struct file *f)
897 {
898         atomic_long_inc(&f->f_count);
899         return f;
900 }
901 #define get_file_rcu(x) atomic_long_inc_not_zero(&(x)->f_count)
902 #define fput_atomic(x)  atomic_long_add_unless(&(x)->f_count, -1, 1)
903 #define file_count(x)   atomic_long_read(&(x)->f_count)
904 
905 #define MAX_NON_LFS     ((1UL<<31) - 1)
906 
907 /* Page cache limit. The filesystems should put that into their s_maxbytes 
908    limits, otherwise bad things can happen in VM. */ 
909 #if BITS_PER_LONG==32
910 #define MAX_LFS_FILESIZE        ((loff_t)ULONG_MAX << PAGE_SHIFT)
911 #elif BITS_PER_LONG==64
912 #define MAX_LFS_FILESIZE        ((loff_t)LLONG_MAX)
913 #endif
914 
915 #define FL_POSIX        1
916 #define FL_FLOCK        2
917 #define FL_DELEG        4       /* NFSv4 delegation */
918 #define FL_ACCESS       8       /* not trying to lock, just looking */
919 #define FL_EXISTS       16      /* when unlocking, test for existence */
920 #define FL_LEASE        32      /* lease held on this file */
921 #define FL_CLOSE        64      /* unlock on close */
922 #define FL_SLEEP        128     /* A blocking lock */
923 #define FL_DOWNGRADE_PENDING    256 /* Lease is being downgraded */
924 #define FL_UNLOCK_PENDING       512 /* Lease is being broken */
925 #define FL_OFDLCK       1024    /* lock is "owned" by struct file */
926 #define FL_LAYOUT       2048    /* outstanding pNFS layout */
927 
928 #define FL_CLOSE_POSIX (FL_POSIX | FL_CLOSE)
929 
930 /*
931  * Special return value from posix_lock_file() and vfs_lock_file() for
932  * asynchronous locking.
933  */
934 #define FILE_LOCK_DEFERRED 1
935 
936 /* legacy typedef, should eventually be removed */
937 typedef void *fl_owner_t;
938 
939 struct file_lock;
940 
941 struct file_lock_operations {
942         void (*fl_copy_lock)(struct file_lock *, struct file_lock *);
943         void (*fl_release_private)(struct file_lock *);
944 };
945 
946 struct lock_manager_operations {
947         int (*lm_compare_owner)(struct file_lock *, struct file_lock *);
948         unsigned long (*lm_owner_key)(struct file_lock *);
949         fl_owner_t (*lm_get_owner)(fl_owner_t);
950         void (*lm_put_owner)(fl_owner_t);
951         void (*lm_notify)(struct file_lock *);  /* unblock callback */
952         int (*lm_grant)(struct file_lock *, int);
953         bool (*lm_break)(struct file_lock *);
954         int (*lm_change)(struct file_lock *, int, struct list_head *);
955         void (*lm_setup)(struct file_lock *, void **);
956 };
957 
958 struct lock_manager {
959         struct list_head list;
960         /*
961          * NFSv4 and up also want opens blocked during the grace period;
962          * NLM doesn't care:
963          */
964         bool block_opens;
965 };
966 
967 struct net;
968 void locks_start_grace(struct net *, struct lock_manager *);
969 void locks_end_grace(struct lock_manager *);
970 int locks_in_grace(struct net *);
971 int opens_in_grace(struct net *);
972 
973 /* that will die - we need it for nfs_lock_info */
974 #include <linux/nfs_fs_i.h>
975 
976 /*
977  * struct file_lock represents a generic "file lock". It's used to represent
978  * POSIX byte range locks, BSD (flock) locks, and leases. It's important to
979  * note that the same struct is used to represent both a request for a lock and
980  * the lock itself, but the same object is never used for both.
981  *
982  * FIXME: should we create a separate "struct lock_request" to help distinguish
983  * these two uses?
984  *
985  * The varous i_flctx lists are ordered by:
986  *
987  * 1) lock owner
988  * 2) lock range start
989  * 3) lock range end
990  *
991  * Obviously, the last two criteria only matter for POSIX locks.
992  */
993 struct file_lock {
994         struct file_lock *fl_next;      /* singly linked list for this inode  */
995         struct list_head fl_list;       /* link into file_lock_context */
996         struct hlist_node fl_link;      /* node in global lists */
997         struct list_head fl_block;      /* circular list of blocked processes */
998         fl_owner_t fl_owner;
999         unsigned int fl_flags;
1000         unsigned char fl_type;
1001         unsigned int fl_pid;
1002         int fl_link_cpu;                /* what cpu's list is this on? */
1003         struct pid *fl_nspid;
1004         wait_queue_head_t fl_wait;
1005         struct file *fl_file;
1006         loff_t fl_start;
1007         loff_t fl_end;
1008 
1009         struct fasync_struct *  fl_fasync; /* for lease break notifications */
1010         /* for lease breaks: */
1011         unsigned long fl_break_time;
1012         unsigned long fl_downgrade_time;
1013 
1014         const struct file_lock_operations *fl_ops;      /* Callbacks for filesystems */
1015         const struct lock_manager_operations *fl_lmops; /* Callbacks for lockmanagers */
1016         union {
1017                 struct nfs_lock_info    nfs_fl;
1018                 struct nfs4_lock_info   nfs4_fl;
1019                 struct {
1020                         struct list_head link;  /* link in AFS vnode's pending_locks list */
1021                         int state;              /* state of grant or error if -ve */
1022                 } afs;
1023         } fl_u;
1024 } __randomize_layout;
1025 
1026 struct file_lock_context {
1027         spinlock_t              flc_lock;
1028         struct list_head        flc_flock;
1029         struct list_head        flc_posix;
1030         struct list_head        flc_lease;
1031 };
1032 
1033 /* The following constant reflects the upper bound of the file/locking space */
1034 #ifndef OFFSET_MAX
1035 #define INT_LIMIT(x)    (~((x)1 << (sizeof(x)*8 - 1)))
1036 #define OFFSET_MAX      INT_LIMIT(loff_t)
1037 #define OFFT_OFFSET_MAX INT_LIMIT(off_t)
1038 #endif
1039 
1040 extern void send_sigio(struct fown_struct *fown, int fd, int band);
1041 
1042 /*
1043  * Return the inode to use for locking
1044  *
1045  * For overlayfs this should be the overlay inode, not the real inode returned
1046  * by file_inode().  For any other fs file_inode(filp) and locks_inode(filp) are
1047  * equal.
1048  */
1049 static inline struct inode *locks_inode(const struct file *f)
1050 {
1051         return f->f_path.dentry->d_inode;
1052 }
1053 
1054 #ifdef CONFIG_FILE_LOCKING
1055 extern int fcntl_getlk(struct file *, unsigned int, struct flock *);
1056 extern int fcntl_setlk(unsigned int, struct file *, unsigned int,
1057                         struct flock *);
1058 
1059 #if BITS_PER_LONG == 32
1060 extern int fcntl_getlk64(struct file *, unsigned int, struct flock64 *);
1061 extern int fcntl_setlk64(unsigned int, struct file *, unsigned int,
1062                         struct flock64 *);
1063 #endif
1064 
1065 extern int fcntl_setlease(unsigned int fd, struct file *filp, long arg);
1066 extern int fcntl_getlease(struct file *filp);
1067 
1068 /* fs/locks.c */
1069 void locks_free_lock_context(struct inode *inode);
1070 void locks_free_lock(struct file_lock *fl);
1071 extern void locks_init_lock(struct file_lock *);
1072 extern struct file_lock * locks_alloc_lock(void);
1073 extern void locks_copy_lock(struct file_lock *, struct file_lock *);
1074 extern void locks_copy_conflock(struct file_lock *, struct file_lock *);
1075 extern void locks_remove_posix(struct file *, fl_owner_t);
1076 extern void locks_remove_file(struct file *);
1077 extern void locks_release_private(struct file_lock *);
1078 extern void posix_test_lock(struct file *, struct file_lock *);
1079 extern int posix_lock_file(struct file *, struct file_lock *, struct file_lock *);
1080 extern int posix_unblock_lock(struct file_lock *);
1081 extern int vfs_test_lock(struct file *, struct file_lock *);
1082 extern int vfs_lock_file(struct file *, unsigned int, struct file_lock *, struct file_lock *);
1083 extern int vfs_cancel_lock(struct file *filp, struct file_lock *fl);
1084 extern int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl);
1085 extern int __break_lease(struct inode *inode, unsigned int flags, unsigned int type);
1086 extern void lease_get_mtime(struct inode *, struct timespec *time);
1087 extern int generic_setlease(struct file *, long, struct file_lock **, void **priv);
1088 extern int vfs_setlease(struct file *, long, struct file_lock **, void **);
1089 extern int lease_modify(struct file_lock *, int, struct list_head *);
1090 struct files_struct;
1091 extern void show_fd_locks(struct seq_file *f,
1092                          struct file *filp, struct files_struct *files);
1093 #else /* !CONFIG_FILE_LOCKING */
1094 static inline int fcntl_getlk(struct file *file, unsigned int cmd,
1095                               struct flock __user *user)
1096 {
1097         return -EINVAL;
1098 }
1099 
1100 static inline int fcntl_setlk(unsigned int fd, struct file *file,
1101                               unsigned int cmd, struct flock __user *user)
1102 {
1103         return -EACCES;
1104 }
1105 
1106 #if BITS_PER_LONG == 32
1107 static inline int fcntl_getlk64(struct file *file, unsigned int cmd,
1108                                 struct flock64 __user *user)
1109 {
1110         return -EINVAL;
1111 }
1112 
1113 static inline int fcntl_setlk64(unsigned int fd, struct file *file,
1114                                 unsigned int cmd, struct flock64 __user *user)
1115 {
1116         return -EACCES;
1117 }
1118 #endif
1119 static inline int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
1120 {
1121         return -EINVAL;
1122 }
1123 
1124 static inline int fcntl_getlease(struct file *filp)
1125 {
1126         return F_UNLCK;
1127 }
1128 
1129 static inline void
1130 locks_free_lock_context(struct inode *inode)
1131 {
1132 }
1133 
1134 static inline void locks_init_lock(struct file_lock *fl)
1135 {
1136         return;
1137 }
1138 
1139 static inline void locks_copy_conflock(struct file_lock *new, struct file_lock *fl)
1140 {
1141         return;
1142 }
1143 
1144 static inline void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
1145 {
1146         return;
1147 }
1148 
1149 static inline void locks_remove_posix(struct file *filp, fl_owner_t owner)
1150 {
1151         return;
1152 }
1153 
1154 static inline void locks_remove_file(struct file *filp)
1155 {
1156         return;
1157 }
1158 
1159 static inline void posix_test_lock(struct file *filp, struct file_lock *fl)
1160 {
1161         return;
1162 }
1163 
1164 static inline int posix_lock_file(struct file *filp, struct file_lock *fl,
1165                                   struct file_lock *conflock)
1166 {
1167         return -ENOLCK;
1168 }
1169 
1170 static inline int posix_unblock_lock(struct file_lock *waiter)
1171 {
1172         return -ENOENT;
1173 }
1174 
1175 static inline int vfs_test_lock(struct file *filp, struct file_lock *fl)
1176 {
1177         return 0;
1178 }
1179 
1180 static inline int vfs_lock_file(struct file *filp, unsigned int cmd,
1181                                 struct file_lock *fl, struct file_lock *conf)
1182 {
1183         return -ENOLCK;
1184 }
1185 
1186 static inline int vfs_cancel_lock(struct file *filp, struct file_lock *fl)
1187 {
1188         return 0;
1189 }
1190 
1191 static inline int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl)
1192 {
1193         return -ENOLCK;
1194 }
1195 
1196 static inline int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
1197 {
1198         return 0;
1199 }
1200 
1201 static inline void lease_get_mtime(struct inode *inode, struct timespec *time)
1202 {
1203         return;
1204 }
1205 
1206 static inline int generic_setlease(struct file *filp, long arg,
1207                                     struct file_lock **flp, void **priv)
1208 {
1209         return -EINVAL;
1210 }
1211 
1212 static inline int vfs_setlease(struct file *filp, long arg,
1213                                struct file_lock **lease, void **priv)
1214 {
1215         return -EINVAL;
1216 }
1217 
1218 static inline int lease_modify(struct file_lock *fl, int arg,
1219                                struct list_head *dispose)
1220 {
1221         return -EINVAL;
1222 }
1223 
1224 struct files_struct;
1225 static inline void show_fd_locks(struct seq_file *f,
1226                         struct file *filp, struct files_struct *files) {}
1227 #endif /* !CONFIG_FILE_LOCKING */
1228 
1229 static inline struct inode *file_inode(const struct file *f)
1230 {
1231         return f->f_inode;
1232 }
1233 
1234 static inline struct dentry *file_dentry(const struct file *file)
1235 {
1236         return d_real(file->f_path.dentry, file_inode(file), 0);
1237 }
1238 
1239 static inline int locks_lock_file_wait(struct file *filp, struct file_lock *fl)
1240 {
1241         return locks_lock_inode_wait(locks_inode(filp), fl);
1242 }
1243 
1244 struct fasync_struct {
1245         spinlock_t              fa_lock;
1246         int                     magic;
1247         int                     fa_fd;
1248         struct fasync_struct    *fa_next; /* singly linked list */
1249         struct file             *fa_file;
1250         struct rcu_head         fa_rcu;
1251 };
1252 
1253 #define FASYNC_MAGIC 0x4601
1254 
1255 /* SMP safe fasync helpers: */
1256 extern int fasync_helper(int, struct file *, int, struct fasync_struct **);
1257 extern struct fasync_struct *fasync_insert_entry(int, struct file *, struct fasync_struct **, struct fasync_struct *);
1258 extern int fasync_remove_entry(struct file *, struct fasync_struct **);
1259 extern struct fasync_struct *fasync_alloc(void);
1260 extern void fasync_free(struct fasync_struct *);
1261 
1262 /* can be called from interrupts */
1263 extern void kill_fasync(struct fasync_struct **, int, int);
1264 
1265 extern void __f_setown(struct file *filp, struct pid *, enum pid_type, int force);
1266 extern int f_setown(struct file *filp, unsigned long arg, int force);
1267 extern void f_delown(struct file *filp);
1268 extern pid_t f_getown(struct file *filp);
1269 extern int send_sigurg(struct fown_struct *fown);
1270 
1271 struct mm_struct;
1272 
1273 /*
1274  *      Umount options
1275  */
1276 
1277 #define MNT_FORCE       0x00000001      /* Attempt to forcibily umount */
1278 #define MNT_DETACH      0x00000002      /* Just detach from the tree */
1279 #define MNT_EXPIRE      0x00000004      /* Mark for expiry */
1280 #define UMOUNT_NOFOLLOW 0x00000008      /* Don't follow symlink on umount */
1281 #define UMOUNT_UNUSED   0x80000000      /* Flag guaranteed to be unused */
1282 
1283 /* sb->s_iflags */
1284 #define SB_I_CGROUPWB   0x00000001      /* cgroup-aware writeback enabled */
1285 #define SB_I_NOEXEC     0x00000002      /* Ignore executables on this fs */
1286 #define SB_I_NODEV      0x00000004      /* Ignore devices on this fs */
1287 
1288 /* sb->s_iflags to limit user namespace mounts */
1289 #define SB_I_USERNS_VISIBLE             0x00000010 /* fstype already mounted */
1290 
1291 /* Possible states of 'frozen' field */
1292 enum {
1293         SB_UNFROZEN = 0,                /* FS is unfrozen */
1294         SB_FREEZE_WRITE = 1,            /* Writes, dir ops, ioctls frozen */
1295         SB_FREEZE_PAGEFAULT = 2,        /* Page faults stopped as well */
1296         SB_FREEZE_FS = 3,               /* For internal FS use (e.g. to stop
1297                                          * internal threads if needed) */
1298         SB_FREEZE_COMPLETE = 4,         /* ->freeze_fs finished successfully */
1299 };
1300 
1301 #define SB_FREEZE_LEVELS (SB_FREEZE_COMPLETE - 1)
1302 
1303 struct sb_writers {
1304         int                             frozen;         /* Is sb frozen? */
1305         wait_queue_head_t               wait_unfrozen;  /* for get_super_thawed() */
1306         struct percpu_rw_semaphore      rw_sem[SB_FREEZE_LEVELS];
1307 };
1308 
1309 struct super_block {
1310         struct list_head        s_list;         /* Keep this first */
1311         dev_t                   s_dev;          /* search index; _not_ kdev_t */
1312         unsigned char           s_blocksize_bits;
1313         unsigned long           s_blocksize;
1314         loff_t                  s_maxbytes;     /* Max file size */
1315         struct file_system_type *s_type;
1316         const struct super_operations   *s_op;
1317         const struct dquot_operations   *dq_op;
1318         const struct quotactl_ops       *s_qcop;
1319         const struct export_operations *s_export_op;
1320         unsigned long           s_flags;
1321         unsigned long           s_iflags;       /* internal SB_I_* flags */
1322         unsigned long           s_magic;
1323         struct dentry           *s_root;
1324         struct rw_semaphore     s_umount;
1325         int                     s_count;
1326         atomic_t                s_active;
1327 #ifdef CONFIG_SECURITY
1328         void                    *s_security;
1329 #endif
1330         const struct xattr_handler **s_xattr;
1331 
1332         const struct fscrypt_operations *s_cop;
1333 
1334         struct hlist_bl_head    s_anon;         /* anonymous dentries for (nfs) exporting */
1335         struct list_head        s_mounts;       /* list of mounts; _not_ for fs use */
1336         struct block_device     *s_bdev;
1337         struct backing_dev_info *s_bdi;
1338         struct mtd_info         *s_mtd;
1339         struct hlist_node       s_instances;
1340         unsigned int            s_quota_types;  /* Bitmask of supported quota types */
1341         struct quota_info       s_dquot;        /* Diskquota specific options */
1342 
1343         struct sb_writers       s_writers;
1344 
1345         char                    s_id[32];       /* Informational name */
1346         uuid_t                  s_uuid;         /* UUID */
1347 
1348         void                    *s_fs_info;     /* Filesystem private info */
1349         unsigned int            s_max_links;
1350         fmode_t                 s_mode;
1351 
1352         /* Granularity of c/m/atime in ns.
1353            Cannot be worse than a second */
1354         u32                s_time_gran;
1355 
1356         /*
1357          * The next field is for VFS *only*. No filesystems have any business
1358          * even looking at it. You had been warned.
1359          */
1360         struct mutex s_vfs_rename_mutex;        /* Kludge */
1361 
1362         /*
1363          * Filesystem subtype.  If non-empty the filesystem type field
1364          * in /proc/mounts will be "type.subtype"
1365          */
1366         char *s_subtype;
1367 
1368         const struct dentry_operations *s_d_op; /* default d_op for dentries */
1369 
1370         /*
1371          * Saved pool identifier for cleancache (-1 means none)
1372          */
1373         int cleancache_poolid;
1374 
1375         struct shrinker s_shrink;       /* per-sb shrinker handle */
1376 
1377         /* Number of inodes with nlink == 0 but still referenced */
1378         atomic_long_t s_remove_count;
1379 
1380         /* Being remounted read-only */
1381         int s_readonly_remount;
1382 
1383         /* AIO completions deferred from interrupt context */
1384         struct workqueue_struct *s_dio_done_wq;
1385         struct hlist_head s_pins;
1386 
1387         /*
1388          * Owning user namespace and default context in which to
1389          * interpret filesystem uids, gids, quotas, device nodes,
1390          * xattrs and security labels.
1391          */
1392         struct user_namespace *s_user_ns;
1393 
1394         /*
1395          * Keep the lru lists last in the structure so they always sit on their
1396          * own individual cachelines.
1397          */
1398         struct list_lru         s_dentry_lru ____cacheline_aligned_in_smp;
1399         struct list_lru         s_inode_lru ____cacheline_aligned_in_smp;
1400         struct rcu_head         rcu;
1401         struct work_struct      destroy_work;
1402 
1403         struct mutex            s_sync_lock;    /* sync serialisation lock */
1404 
1405         /*
1406          * Indicates how deep in a filesystem stack this SB is
1407          */
1408         int s_stack_depth;
1409 
1410         /* s_inode_list_lock protects s_inodes */
1411         spinlock_t              s_inode_list_lock ____cacheline_aligned_in_smp;
1412         struct list_head        s_inodes;       /* all inodes */
1413 
1414         spinlock_t              s_inode_wblist_lock;
1415         struct list_head        s_inodes_wb;    /* writeback inodes */
1416 } __randomize_layout;
1417 
1418 /* Helper functions so that in most cases filesystems will
1419  * not need to deal directly with kuid_t and kgid_t and can
1420  * instead deal with the raw numeric values that are stored
1421  * in the filesystem.
1422  */
1423 static inline uid_t i_uid_read(const struct inode *inode)
1424 {
1425         return from_kuid(inode->i_sb->s_user_ns, inode->i_uid);
1426 }
1427 
1428 static inline gid_t i_gid_read(const struct inode *inode)
1429 {
1430         return from_kgid(inode->i_sb->s_user_ns, inode->i_gid);
1431 }
1432 
1433 static inline void i_uid_write(struct inode *inode, uid_t uid)
1434 {
1435         inode->i_uid = make_kuid(inode->i_sb->s_user_ns, uid);
1436 }
1437 
1438 static inline void i_gid_write(struct inode *inode, gid_t gid)
1439 {
1440         inode->i_gid = make_kgid(inode->i_sb->s_user_ns, gid);
1441 }
1442 
1443 extern struct timespec current_time(struct inode *inode);
1444 
1445 /*
1446  * Snapshotting support.
1447  */
1448 
1449 void __sb_end_write(struct super_block *sb, int level);
1450 int __sb_start_write(struct super_block *sb, int level, bool wait);
1451 
1452 #define __sb_writers_acquired(sb, lev)  \
1453         percpu_rwsem_acquire(&(sb)->s_writers.rw_sem[(lev)-1], 1, _THIS_IP_)
1454 #define __sb_writers_release(sb, lev)   \
1455         percpu_rwsem_release(&(sb)->s_writers.rw_sem[(lev)-1], 1, _THIS_IP_)
1456 
1457 /**
1458  * sb_end_write - drop write access to a superblock
1459  * @sb: the super we wrote to
1460  *
1461  * Decrement number of writers to the filesystem. Wake up possible waiters
1462  * wanting to freeze the filesystem.
1463  */
1464 static inline void sb_end_write(struct super_block *sb)
1465 {
1466         __sb_end_write(sb, SB_FREEZE_WRITE);
1467 }
1468 
1469 /**
1470  * sb_end_pagefault - drop write access to a superblock from a page fault
1471  * @sb: the super we wrote to
1472  *
1473  * Decrement number of processes handling write page fault to the filesystem.
1474  * Wake up possible waiters wanting to freeze the filesystem.
1475  */
1476 static inline void sb_end_pagefault(struct super_block *sb)
1477 {
1478         __sb_end_write(sb, SB_FREEZE_PAGEFAULT);
1479 }
1480 
1481 /**
1482  * sb_end_intwrite - drop write access to a superblock for internal fs purposes
1483  * @sb: the super we wrote to
1484  *
1485  * Decrement fs-internal number of writers to the filesystem.  Wake up possible
1486  * waiters wanting to freeze the filesystem.
1487  */
1488 static inline void sb_end_intwrite(struct super_block *sb)
1489 {
1490         __sb_end_write(sb, SB_FREEZE_FS);
1491 }
1492 
1493 /**
1494  * sb_start_write - get write access to a superblock
1495  * @sb: the super we write to
1496  *
1497  * When a process wants to write data or metadata to a file system (i.e. dirty
1498  * a page or an inode), it should embed the operation in a sb_start_write() -
1499  * sb_end_write() pair to get exclusion against file system freezing. This
1500  * function increments number of writers preventing freezing. If the file
1501  * system is already frozen, the function waits until the file system is
1502  * thawed.
1503  *
1504  * Since freeze protection behaves as a lock, users have to preserve
1505  * ordering of freeze protection and other filesystem locks. Generally,
1506  * freeze protection should be the outermost lock. In particular, we have:
1507  *
1508  * sb_start_write
1509  *   -> i_mutex                 (write path, truncate, directory ops, ...)
1510  *   -> s_umount                (freeze_super, thaw_super)
1511  */
1512 static inline void sb_start_write(struct super_block *sb)
1513 {
1514         __sb_start_write(sb, SB_FREEZE_WRITE, true);
1515 }
1516 
1517 static inline int sb_start_write_trylock(struct super_block *sb)
1518 {
1519         return __sb_start_write(sb, SB_FREEZE_WRITE, false);
1520 }
1521 
1522 /**
1523  * sb_start_pagefault - get write access to a superblock from a page fault
1524  * @sb: the super we write to
1525  *
1526  * When a process starts handling write page fault, it should embed the
1527  * operation into sb_start_pagefault() - sb_end_pagefault() pair to get
1528  * exclusion against file system freezing. This is needed since the page fault
1529  * is going to dirty a page. This function increments number of running page
1530  * faults preventing freezing. If the file system is already frozen, the
1531  * function waits until the file system is thawed.
1532  *
1533  * Since page fault freeze protection behaves as a lock, users have to preserve
1534  * ordering of freeze protection and other filesystem locks. It is advised to
1535  * put sb_start_pagefault() close to mmap_sem in lock ordering. Page fault
1536  * handling code implies lock dependency:
1537  *
1538  * mmap_sem
1539  *   -> sb_start_pagefault
1540  */
1541 static inline void sb_start_pagefault(struct super_block *sb)
1542 {
1543         __sb_start_write(sb, SB_FREEZE_PAGEFAULT, true);
1544 }
1545 
1546 /*
1547  * sb_start_intwrite - get write access to a superblock for internal fs purposes
1548  * @sb: the super we write to
1549  *
1550  * This is the third level of protection against filesystem freezing. It is
1551  * free for use by a filesystem. The only requirement is that it must rank
1552  * below sb_start_pagefault.
1553  *
1554  * For example filesystem can call sb_start_intwrite() when starting a
1555  * transaction which somewhat eases handling of freezing for internal sources
1556  * of filesystem changes (internal fs threads, discarding preallocation on file
1557  * close, etc.).
1558  */
1559 static inline void sb_start_intwrite(struct super_block *sb)
1560 {
1561         __sb_start_write(sb, SB_FREEZE_FS, true);
1562 }
1563 
1564 
1565 extern bool inode_owner_or_capable(const struct inode *inode);
1566 
1567 /*
1568  * VFS helper functions..
1569  */
1570 extern int vfs_create(struct inode *, struct dentry *, umode_t, bool);
1571 extern int vfs_mkdir(struct inode *, struct dentry *, umode_t);
1572 extern int vfs_mknod(struct inode *, struct dentry *, umode_t, dev_t);
1573 extern int vfs_symlink(struct inode *, struct dentry *, const char *);
1574 extern int vfs_link(struct dentry *, struct inode *, struct dentry *, struct inode **);
1575 extern int vfs_rmdir(struct inode *, struct dentry *);
1576 extern int vfs_unlink(struct inode *, struct dentry *, struct inode **);
1577 extern int vfs_rename(struct inode *, struct dentry *, struct inode *, struct dentry *, struct inode **, unsigned int);
1578 extern int vfs_whiteout(struct inode *, struct dentry *);
1579 
1580 extern struct dentry *vfs_tmpfile(struct dentry *dentry, umode_t mode,
1581                                   int open_flag);
1582 
1583 /*
1584  * VFS file helper functions.
1585  */
1586 extern void inode_init_owner(struct inode *inode, const struct inode *dir,
1587                         umode_t mode);
1588 extern bool may_open_dev(const struct path *path);
1589 /*
1590  * VFS FS_IOC_FIEMAP helper definitions.
1591  */
1592 struct fiemap_extent_info {
1593         unsigned int fi_flags;          /* Flags as passed from user */
1594         unsigned int fi_extents_mapped; /* Number of mapped extents */
1595         unsigned int fi_extents_max;    /* Size of fiemap_extent array */
1596         struct fiemap_extent __user *fi_extents_start; /* Start of
1597                                                         fiemap_extent array */
1598 };
1599 int fiemap_fill_next_extent(struct fiemap_extent_info *info, u64 logical,
1600                             u64 phys, u64 len, u32 flags);
1601 int fiemap_check_flags(struct fiemap_extent_info *fieinfo, u32 fs_flags);
1602 
1603 /*
1604  * File types
1605  *
1606  * NOTE! These match bits 12..15 of stat.st_mode
1607  * (ie "(i_mode >> 12) & 15").
1608  */
1609 #define DT_UNKNOWN      0
1610 #define DT_FIFO         1
1611 #define DT_CHR          2
1612 #define DT_DIR          4
1613 #define DT_BLK          6
1614 #define DT_REG          8
1615 #define DT_LNK          10
1616 #define DT_SOCK         12
1617 #define DT_WHT          14
1618 
1619 /*
1620  * This is the "filldir" function type, used by readdir() to let
1621  * the kernel specify what kind of dirent layout it wants to have.
1622  * This allows the kernel to read directories into kernel space or
1623  * to have different dirent layouts depending on the binary type.
1624  */
1625 struct dir_context;
1626 typedef int (*filldir_t)(struct dir_context *, const char *, int, loff_t, u64,
1627                          unsigned);
1628 
1629 struct dir_context {
1630         const filldir_t actor;
1631         loff_t pos;
1632 };
1633 
1634 struct block_device_operations;
1635 
1636 /* These macros are for out of kernel modules to test that
1637  * the kernel supports the unlocked_ioctl and compat_ioctl
1638  * fields in struct file_operations. */
1639 #define HAVE_COMPAT_IOCTL 1
1640 #define HAVE_UNLOCKED_IOCTL 1
1641 
1642 /*
1643  * These flags let !MMU mmap() govern direct device mapping vs immediate
1644  * copying more easily for MAP_PRIVATE, especially for ROM filesystems.
1645  *
1646  * NOMMU_MAP_COPY:      Copy can be mapped (MAP_PRIVATE)
1647  * NOMMU_MAP_DIRECT:    Can be mapped directly (MAP_SHARED)
1648  * NOMMU_MAP_READ:      Can be mapped for reading
1649  * NOMMU_MAP_WRITE:     Can be mapped for writing
1650  * NOMMU_MAP_EXEC:      Can be mapped for execution
1651  */
1652 #define NOMMU_MAP_COPY          0x00000001
1653 #define NOMMU_MAP_DIRECT        0x00000008
1654 #define NOMMU_MAP_READ          VM_MAYREAD
1655 #define NOMMU_MAP_WRITE         VM_MAYWRITE
1656 #define NOMMU_MAP_EXEC          VM_MAYEXEC
1657 
1658 #define NOMMU_VMFLAGS \
1659         (NOMMU_MAP_READ | NOMMU_MAP_WRITE | NOMMU_MAP_EXEC)
1660 
1661 
1662 struct iov_iter;
1663 
1664 struct file_operations {
1665         struct module *owner;
1666         loff_t (*llseek) (struct file *, loff_t, int);
1667         ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);
1668         ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
1669         ssize_t (*read_iter) (struct kiocb *, struct iov_iter *);
1670         ssize_t (*write_iter) (struct kiocb *, struct iov_iter *);
1671         int (*iterate) (struct file *, struct dir_context *);
1672         int (*iterate_shared) (struct file *, struct dir_context *);
1673         unsigned int (*poll) (struct file *, struct poll_table_struct *);
1674         long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
1675         long (*compat_ioctl) (struct file *, unsigned int, unsigned long);
1676         int (*mmap) (struct file *, struct vm_area_struct *);
1677         int (*open) (struct inode *, struct file *);
1678         int (*flush) (struct file *, fl_owner_t id);
1679         int (*release) (struct inode *, struct file *);
1680         int (*fsync) (struct file *, loff_t, loff_t, int datasync);
1681         int (*fasync) (int, struct file *, int);
1682         int (*lock) (struct file *, int, struct file_lock *);
1683         ssize_t (*sendpage) (struct file *, struct page *, int, size_t, loff_t *, int);
1684         unsigned long (*get_unmapped_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
1685         int (*check_flags)(int);
1686         int (*flock) (struct file *, int, struct file_lock *);
1687         ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, loff_t *, size_t, unsigned int);
1688         ssize_t (*splice_read)(struct file *, loff_t *, struct pipe_inode_info *, size_t, unsigned int);
1689         int (*setlease)(struct file *, long, struct file_lock **, void **);
1690         long (*fallocate)(struct file *file, int mode, loff_t offset,
1691                           loff_t len);
1692         void (*show_fdinfo)(struct seq_file *m, struct file *f);
1693 #ifndef CONFIG_MMU
1694         unsigned (*mmap_capabilities)(struct file *);
1695 #endif
1696         ssize_t (*copy_file_range)(struct file *, loff_t, struct file *,
1697                         loff_t, size_t, unsigned int);
1698         int (*clone_file_range)(struct file *, loff_t, struct file *, loff_t,
1699                         u64);
1700         ssize_t (*dedupe_file_range)(struct file *, u64, u64, struct file *,
1701                         u64);
1702 } __randomize_layout;
1703 
1704 struct inode_operations {
1705         struct dentry * (*lookup) (struct inode *,struct dentry *, unsigned int);
1706         const char * (*get_link) (struct dentry *, struct inode *, struct delayed_call *);
1707         int (*permission) (struct inode *, int);
1708         struct posix_acl * (*get_acl)(struct inode *, int);
1709 
1710         int (*readlink) (struct dentry *, char __user *,int);
1711 
1712         int (*create) (struct inode *,struct dentry *, umode_t, bool);
1713         int (*link) (struct dentry *,struct inode *,struct dentry *);
1714         int (*unlink) (struct inode *,struct dentry *);
1715         int (*symlink) (struct inode *,struct dentry *,const char *);
1716         int (*mkdir) (struct inode *,struct dentry *,umode_t);
1717         int (*rmdir) (struct inode *,struct dentry *);
1718         int (*mknod) (struct inode *,struct dentry *,umode_t,dev_t);
1719         int (*rename) (struct inode *, struct dentry *,
1720                         struct inode *, struct dentry *, unsigned int);
1721         int (*setattr) (struct dentry *, struct iattr *);
1722         int (*getattr) (const struct path *, struct kstat *, u32, unsigned int);
1723         ssize_t (*listxattr) (struct dentry *, char *, size_t);
1724         int (*fiemap)(struct inode *, struct fiemap_extent_info *, u64 start,
1725                       u64 len);
1726         int (*update_time)(struct inode *, struct timespec *, int);
1727         int (*atomic_open)(struct inode *, struct dentry *,
1728                            struct file *, unsigned open_flag,
1729                            umode_t create_mode, int *opened);
1730         int (*tmpfile) (struct inode *, struct dentry *, umode_t);
1731         int (*set_acl)(struct inode *, struct posix_acl *, int);
1732 } ____cacheline_aligned;
1733 
1734 static inline ssize_t call_read_iter(struct file *file, struct kiocb *kio,
1735                                      struct iov_iter *iter)
1736 {
1737         return file->f_op->read_iter(kio, iter);
1738 }
1739 
1740 static inline ssize_t call_write_iter(struct file *file, struct kiocb *kio,
1741                                       struct iov_iter *iter)
1742 {
1743         return file->f_op->write_iter(kio, iter);
1744 }
1745 
1746 static inline int call_mmap(struct file *file, struct vm_area_struct *vma)
1747 {
1748         return file->f_op->mmap(file, vma);
1749 }
1750 
1751 ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector,
1752                               unsigned long nr_segs, unsigned long fast_segs,
1753                               struct iovec *fast_pointer,
1754                               struct iovec **ret_pointer);
1755 
1756 extern ssize_t __vfs_read(struct file *, char __user *, size_t, loff_t *);
1757 extern ssize_t __vfs_write(struct file *, const char __user *, size_t, loff_t *);
1758 extern ssize_t vfs_read(struct file *, char __user *, size_t, loff_t *);
1759 extern ssize_t vfs_write(struct file *, const char __user *, size_t, loff_t *);
1760 extern ssize_t vfs_readv(struct file *, const struct iovec __user *,
1761                 unsigned long, loff_t *, int);
1762 extern ssize_t vfs_writev(struct file *, const struct iovec __user *,
1763                 unsigned long, loff_t *, int);
1764 extern ssize_t vfs_copy_file_range(struct file *, loff_t , struct file *,
1765                                    loff_t, size_t, unsigned int);
1766 extern int vfs_clone_file_prep_inodes(struct inode *inode_in, loff_t pos_in,
1767                                       struct inode *inode_out, loff_t pos_out,
1768                                       u64 *len, bool is_dedupe);
1769 extern int vfs_clone_file_range(struct file *file_in, loff_t pos_in,
1770                 struct file *file_out, loff_t pos_out, u64 len);
1771 extern int vfs_dedupe_file_range_compare(struct inode *src, loff_t srcoff,
1772                                          struct inode *dest, loff_t destoff,
1773                                          loff_t len, bool *is_same);
1774 extern int vfs_dedupe_file_range(struct file *file,
1775                                  struct file_dedupe_range *same);
1776 
1777 struct super_operations {
1778         struct inode *(*alloc_inode)(struct super_block *sb);
1779         void (*destroy_inode)(struct inode *);
1780 
1781         void (*dirty_inode) (struct inode *, int flags);
1782         int (*write_inode) (struct inode *, struct writeback_control *wbc);
1783         int (*drop_inode) (struct inode *);
1784         void (*evict_inode) (struct inode *);
1785         void (*put_super) (struct super_block *);
1786         int (*sync_fs)(struct super_block *sb, int wait);
1787         int (*freeze_super) (struct super_block *);
1788         int (*freeze_fs) (struct super_block *);
1789         int (*thaw_super) (struct super_block *);
1790         int (*unfreeze_fs) (struct super_block *);
1791         int (*statfs) (struct dentry *, struct kstatfs *);
1792         int (*remount_fs) (struct super_block *, int *, char *);
1793         void (*umount_begin) (struct super_block *);
1794 
1795         int (*show_options)(struct seq_file *, struct dentry *);
1796         int (*show_devname)(struct seq_file *, struct dentry *);
1797         int (*show_path)(struct seq_file *, struct dentry *);
1798         int (*show_stats)(struct seq_file *, struct dentry *);
1799 #ifdef CONFIG_QUOTA
1800         ssize_t (*quota_read)(struct super_block *, int, char *, size_t, loff_t);
1801         ssize_t (*quota_write)(struct super_block *, int, const char *, size_t, loff_t);
1802         struct dquot **(*get_dquots)(struct inode *);
1803 #endif
1804         int (*bdev_try_to_free_page)(struct super_block*, struct page*, gfp_t);
1805         long (*nr_cached_objects)(struct super_block *,
1806                                   struct shrink_control *);
1807         long (*free_cached_objects)(struct super_block *,
1808                                     struct shrink_control *);
1809 };
1810 
1811 /*
1812  * Inode flags - they have no relation to superblock flags now
1813  */
1814 #define S_SYNC          1       /* Writes are synced at once */
1815 #define S_NOATIME       2       /* Do not update access times */
1816 #define S_APPEND        4       /* Append-only file */
1817 #define S_IMMUTABLE     8       /* Immutable file */
1818 #define S_DEAD          16      /* removed, but still open directory */
1819 #define S_NOQUOTA       32      /* Inode is not counted to quota */
1820 #define S_DIRSYNC       64      /* Directory modifications are synchronous */
1821 #define S_NOCMTIME      128     /* Do not update file c/mtime */
1822 #define S_SWAPFILE      256     /* Do not truncate: swapon got its bmaps */
1823 #define S_PRIVATE       512     /* Inode is fs-internal */
1824 #define S_IMA           1024    /* Inode has an associated IMA struct */
1825 #define S_AUTOMOUNT     2048    /* Automount/referral quasi-directory */
1826 #define S_NOSEC         4096    /* no suid or xattr security attributes */
1827 #ifdef CONFIG_FS_DAX
1828 #define S_DAX           8192    /* Direct Access, avoiding the page cache */
1829 #else
1830 #define S_DAX           0       /* Make all the DAX code disappear */
1831 #endif
1832 
1833 /*
1834  * Note that nosuid etc flags are inode-specific: setting some file-system
1835  * flags just means all the inodes inherit those flags by default. It might be
1836  * possible to override it selectively if you really wanted to with some
1837  * ioctl() that is not currently implemented.
1838  *
1839  * Exception: MS_RDONLY is always applied to the entire file system.
1840  *
1841  * Unfortunately, it is possible to change a filesystems flags with it mounted
1842  * with files in use.  This means that all of the inodes will not have their
1843  * i_flags updated.  Hence, i_flags no longer inherit the superblock mount
1844  * flags, so these have to be checked separately. -- rmk@arm.uk.linux.org
1845  */
1846 #define __IS_FLG(inode, flg)    ((inode)->i_sb->s_flags & (flg))
1847 
1848 #define IS_RDONLY(inode)        ((inode)->i_sb->s_flags & MS_RDONLY)
1849 #define IS_SYNC(inode)          (__IS_FLG(inode, MS_SYNCHRONOUS) || \
1850                                         ((inode)->i_flags & S_SYNC))
1851 #define IS_DIRSYNC(inode)       (__IS_FLG(inode, MS_SYNCHRONOUS|MS_DIRSYNC) || \
1852                                         ((inode)->i_flags & (S_SYNC|S_DIRSYNC)))
1853 #define IS_MANDLOCK(inode)      __IS_FLG(inode, MS_MANDLOCK)
1854 #define IS_NOATIME(inode)       __IS_FLG(inode, MS_RDONLY|MS_NOATIME)
1855 #define IS_I_VERSION(inode)     __IS_FLG(inode, MS_I_VERSION)
1856 
1857 #define IS_NOQUOTA(inode)       ((inode)->i_flags & S_NOQUOTA)
1858 #define IS_APPEND(inode)        ((inode)->i_flags & S_APPEND)
1859 #define IS_IMMUTABLE(inode)     ((inode)->i_flags & S_IMMUTABLE)
1860 #define IS_POSIXACL(inode)      __IS_FLG(inode, MS_POSIXACL)
1861 
1862 #define IS_DEADDIR(inode)       ((inode)->i_flags & S_DEAD)
1863 #define IS_NOCMTIME(inode)      ((inode)->i_flags & S_NOCMTIME)
1864 #define IS_SWAPFILE(inode)      ((inode)->i_flags & S_SWAPFILE)
1865 #define IS_PRIVATE(inode)       ((inode)->i_flags & S_PRIVATE)
1866 #define IS_IMA(inode)           ((inode)->i_flags & S_IMA)
1867 #define IS_AUTOMOUNT(inode)     ((inode)->i_flags & S_AUTOMOUNT)
1868 #define IS_NOSEC(inode)         ((inode)->i_flags & S_NOSEC)
1869 #define IS_DAX(inode)           ((inode)->i_flags & S_DAX)
1870 
1871 #define IS_WHITEOUT(inode)      (S_ISCHR(inode->i_mode) && \
1872                                  (inode)->i_rdev == WHITEOUT_DEV)
1873 
1874 static inline bool HAS_UNMAPPED_ID(struct inode *inode)
1875 {
1876         return !uid_valid(inode->i_uid) || !gid_valid(inode->i_gid);
1877 }
1878 
1879 static inline enum rw_hint file_write_hint(struct file *file)
1880 {
1881         if (file->f_write_hint != WRITE_LIFE_NOT_SET)
1882                 return file->f_write_hint;
1883 
1884         return file_inode(file)->i_write_hint;
1885 }
1886 
1887 static inline int iocb_flags(struct file *file);
1888 
1889 static inline void init_sync_kiocb(struct kiocb *kiocb, struct file *filp)
1890 {
1891         *kiocb = (struct kiocb) {
1892                 .ki_filp = filp,
1893                 .ki_flags = iocb_flags(filp),
1894                 .ki_hint = file_write_hint(filp),
1895         };
1896 }
1897 
1898 /*
1899  * Inode state bits.  Protected by inode->i_lock
1900  *
1901  * Three bits determine the dirty state of the inode, I_DIRTY_SYNC,
1902  * I_DIRTY_DATASYNC and I_DIRTY_PAGES.
1903  *
1904  * Four bits define the lifetime of an inode.  Initially, inodes are I_NEW,
1905  * until that flag is cleared.  I_WILL_FREE, I_FREEING and I_CLEAR are set at
1906  * various stages of removing an inode.
1907  *
1908  * Two bits are used for locking and completion notification, I_NEW and I_SYNC.
1909  *
1910  * I_DIRTY_SYNC         Inode is dirty, but doesn't have to be written on
1911  *                      fdatasync().  i_atime is the usual cause.
1912  * I_DIRTY_DATASYNC     Data-related inode changes pending. We keep track of
1913  *                      these changes separately from I_DIRTY_SYNC so that we
1914  *                      don't have to write inode on fdatasync() when only
1915  *                      mtime has changed in it.
1916  * I_DIRTY_PAGES        Inode has dirty pages.  Inode itself may be clean.
1917  * I_NEW                Serves as both a mutex and completion notification.
1918  *                      New inodes set I_NEW.  If two processes both create
1919  *                      the same inode, one of them will release its inode and
1920  *                      wait for I_NEW to be released before returning.
1921  *                      Inodes in I_WILL_FREE, I_FREEING or I_CLEAR state can
1922  *                      also cause waiting on I_NEW, without I_NEW actually
1923  *                      being set.  find_inode() uses this to prevent returning
1924  *                      nearly-dead inodes.
1925  * I_WILL_FREE          Must be set when calling write_inode_now() if i_count
1926  *                      is zero.  I_FREEING must be set when I_WILL_FREE is
1927  *                      cleared.
1928  * I_FREEING            Set when inode is about to be freed but still has dirty
1929  *                      pages or buffers attached or the inode itself is still
1930  *                      dirty.
1931  * I_CLEAR              Added by clear_inode().  In this state the inode is
1932  *                      clean and can be destroyed.  Inode keeps I_FREEING.
1933  *
1934  *                      Inodes that are I_WILL_FREE, I_FREEING or I_CLEAR are
1935  *                      prohibited for many purposes.  iget() must wait for
1936  *                      the inode to be completely released, then create it
1937  *                      anew.  Other functions will just ignore such inodes,
1938  *                      if appropriate.  I_NEW is used for waiting.
1939  *
1940  * I_SYNC               Writeback of inode is running. The bit is set during
1941  *                      data writeback, and cleared with a wakeup on the bit
1942  *                      address once it is done. The bit is also used to pin
1943  *                      the inode in memory for flusher thread.
1944  *
1945  * I_REFERENCED         Marks the inode as recently references on the LRU list.
1946  *
1947  * I_DIO_WAKEUP         Never set.  Only used as a key for wait_on_bit().
1948  *
1949  * I_WB_SWITCH          Cgroup bdi_writeback switching in progress.  Used to
1950  *                      synchronize competing switching instances and to tell
1951  *                      wb stat updates to grab mapping->tree_lock.  See
1952  *                      inode_switch_wb_work_fn() for details.
1953  *
1954  * I_OVL_INUSE          Used by overlayfs to get exclusive ownership on upper
1955  *                      and work dirs among overlayfs mounts.
1956  *
1957  * Q: What is the difference between I_WILL_FREE and I_FREEING?
1958  */
1959 #define I_DIRTY_SYNC            (1 << 0)
1960 #define I_DIRTY_DATASYNC        (1 << 1)
1961 #define I_DIRTY_PAGES           (1 << 2)
1962 #define __I_NEW                 3
1963 #define I_NEW                   (1 << __I_NEW)
1964 #define I_WILL_FREE             (1 << 4)
1965 #define I_FREEING               (1 << 5)
1966 #define I_CLEAR                 (1 << 6)
1967 #define __I_SYNC                7
1968 #define I_SYNC                  (1 << __I_SYNC)
1969 #define I_REFERENCED            (1 << 8)
1970 #define __I_DIO_WAKEUP          9
1971 #define I_DIO_WAKEUP            (1 << __I_DIO_WAKEUP)
1972 #define I_LINKABLE              (1 << 10)
1973 #define I_DIRTY_TIME            (1 << 11)
1974 #define __I_DIRTY_TIME_EXPIRED  12
1975 #define I_DIRTY_TIME_EXPIRED    (1 << __I_DIRTY_TIME_EXPIRED)
1976 #define I_WB_SWITCH             (1 << 13)
1977 #define I_OVL_INUSE                     (1 << 14)
1978 
1979 #define I_DIRTY (I_DIRTY_SYNC | I_DIRTY_DATASYNC | I_DIRTY_PAGES)
1980 #define I_DIRTY_ALL (I_DIRTY | I_DIRTY_TIME)
1981 
1982 extern void __mark_inode_dirty(struct inode *, int);
1983 static inline void mark_inode_dirty(struct inode *inode)
1984 {
1985         __mark_inode_dirty(inode, I_DIRTY);
1986 }
1987 
1988 static inline void mark_inode_dirty_sync(struct inode *inode)
1989 {
1990         __mark_inode_dirty(inode, I_DIRTY_SYNC);
1991 }
1992 
1993 extern void inc_nlink(struct inode *inode);
1994 extern void drop_nlink(struct inode *inode);
1995 extern void clear_nlink(struct inode *inode);
1996 extern void set_nlink(struct inode *inode, unsigned int nlink);
1997 
1998 static inline void inode_inc_link_count(struct inode *inode)
1999 {
2000         inc_nlink(inode);
2001         mark_inode_dirty(inode);
2002 }
2003 
2004 static inline void inode_dec_link_count(struct inode *inode)
2005 {
2006         drop_nlink(inode);
2007         mark_inode_dirty(inode);
2008 }
2009 
2010 /**
2011  * inode_inc_iversion - increments i_version
2012  * @inode: inode that need to be updated
2013  *
2014  * Every time the inode is modified, the i_version field will be incremented.
2015  * The filesystem has to be mounted with i_version flag
2016  */
2017 
2018 static inline void inode_inc_iversion(struct inode *inode)
2019 {
2020        spin_lock(&inode->i_lock);
2021        inode->i_version++;
2022        spin_unlock(&inode->i_lock);
2023 }
2024 
2025 enum file_time_flags {
2026         S_ATIME = 1,
2027         S_MTIME = 2,
2028         S_CTIME = 4,
2029         S_VERSION = 8,
2030 };
2031 
2032 extern void touch_atime(const struct path *);
2033 static inline void file_accessed(struct file *file)
2034 {
2035         if (!(file->f_flags & O_NOATIME))
2036                 touch_atime(&file->f_path);
2037 }
2038 
2039 int sync_inode(struct inode *inode, struct writeback_control *wbc);
2040 int sync_inode_metadata(struct inode *inode, int wait);
2041 
2042 struct file_system_type {
2043         const char *name;
2044         int fs_flags;
2045 #define FS_REQUIRES_DEV         1 
2046 #define FS_BINARY_MOUNTDATA     2
2047 #define FS_HAS_SUBTYPE          4
2048 #define FS_USERNS_MOUNT         8       /* Can be mounted by userns root */
2049 #define FS_RENAME_DOES_D_MOVE   32768   /* FS will handle d_move() during rename() internally. */
2050         struct dentry *(*mount) (struct file_system_type *, int,
2051                        const char *, void *);
2052         void (*kill_sb) (struct super_block *);
2053         struct module *owner;
2054         struct file_system_type * next;
2055         struct hlist_head fs_supers;
2056 
2057         struct lock_class_key s_lock_key;
2058         struct lock_class_key s_umount_key;
2059         struct lock_class_key s_vfs_rename_key;
2060         struct lock_class_key s_writers_key[SB_FREEZE_LEVELS];
2061 
2062         struct lock_class_key i_lock_key;
2063         struct lock_class_key i_mutex_key;
2064         struct lock_class_key i_mutex_dir_key;
2065 };
2066 
2067 #define MODULE_ALIAS_FS(NAME) MODULE_ALIAS("fs-" NAME)
2068 
2069 extern struct dentry *mount_ns(struct file_system_type *fs_type,
2070         int flags, void *data, void *ns, struct user_namespace *user_ns,
2071         int (*fill_super)(struct super_block *, void *, int));
2072 extern struct dentry *mount_bdev(struct file_system_type *fs_type,
2073         int flags, const char *dev_name, void *data,
2074         int (*fill_super)(struct super_block *, void *, int));
2075 extern struct dentry *mount_single(struct file_system_type *fs_type,
2076         int flags, void *data,
2077         int (*fill_super)(struct super_block *, void *, int));
2078 extern struct dentry *mount_nodev(struct file_system_type *fs_type,
2079         int flags, void *data,
2080         int (*fill_super)(struct super_block *, void *, int));
2081 extern struct dentry *mount_subtree(struct vfsmount *mnt, const char *path);
2082 void generic_shutdown_super(struct super_block *sb);
2083 void kill_block_super(struct super_block *sb);
2084 void kill_anon_super(struct super_block *sb);
2085 void kill_litter_super(struct super_block *sb);
2086 void deactivate_super(struct super_block *sb);
2087 void deactivate_locked_super(struct super_block *sb);
2088 int set_anon_super(struct super_block *s, void *data);
2089 int get_anon_bdev(dev_t *);
2090 void free_anon_bdev(dev_t);
2091 struct super_block *sget_userns(struct file_system_type *type,
2092                         int (*test)(struct super_block *,void *),
2093                         int (*set)(struct super_block *,void *),
2094                         int flags, struct user_namespace *user_ns,
2095                         void *data);
2096 struct super_block *sget(struct file_system_type *type,
2097                         int (*test)(struct super_block *,void *),
2098                         int (*set)(struct super_block *,void *),
2099                         int flags, void *data);
2100 extern struct dentry *mount_pseudo_xattr(struct file_system_type *, char *,
2101                                          const struct super_operations *ops,
2102                                          const struct xattr_handler **xattr,
2103                                          const struct dentry_operations *dops,
2104                                          unsigned long);
2105 
2106 static inline struct dentry *
2107 mount_pseudo(struct file_system_type *fs_type, char *name,
2108              const struct super_operations *ops,
2109              const struct dentry_operations *dops, unsigned long magic)
2110 {
2111         return mount_pseudo_xattr(fs_type, name, ops, NULL, dops, magic);
2112 }
2113 
2114 /* Alas, no aliases. Too much hassle with bringing module.h everywhere */
2115 #define fops_get(fops) \
2116         (((fops) && try_module_get((fops)->owner) ? (fops) : NULL))
2117 #define fops_put(fops) \
2118         do { if (fops) module_put((fops)->owner); } while(0)
2119 /*
2120  * This one is to be used *ONLY* from ->open() instances.
2121  * fops must be non-NULL, pinned down *and* module dependencies
2122  * should be sufficient to pin the caller down as well.
2123  */
2124 #define replace_fops(f, fops) \
2125         do {    \
2126                 struct file *__file = (f); \
2127                 fops_put(__file->f_op); \
2128                 BUG_ON(!(__file->f_op = (fops))); \
2129         } while(0)
2130 
2131 extern int register_filesystem(struct file_system_type *);
2132 extern int unregister_filesystem(struct file_system_type *);
2133 extern struct vfsmount *kern_mount_data(struct file_system_type *, void *data);
2134 #define kern_mount(type) kern_mount_data(type, NULL)
2135 extern void kern_unmount(struct vfsmount *mnt);
2136 extern int may_umount_tree(struct vfsmount *);
2137 extern int may_umount(struct vfsmount *);
2138 extern long do_mount(const char *, const char __user *,
2139                      const char *, unsigned long, void *);
2140 extern struct vfsmount *collect_mounts(const struct path *);
2141 extern void drop_collected_mounts(struct vfsmount *);
2142 extern int iterate_mounts(int (*)(struct vfsmount *, void *), void *,
2143                           struct vfsmount *);
2144 extern int vfs_statfs(const struct path *, struct kstatfs *);
2145 extern int user_statfs(const char __user *, struct kstatfs *);
2146 extern int fd_statfs(int, struct kstatfs *);
2147 extern int vfs_ustat(dev_t, struct kstatfs *);
2148 extern int freeze_super(struct super_block *super);
2149 extern int thaw_super(struct super_block *super);
2150 extern bool our_mnt(struct vfsmount *mnt);
2151 extern __printf(2, 3)
2152 int super_setup_bdi_name(struct super_block *sb, char *fmt, ...);
2153 extern int super_setup_bdi(struct super_block *sb);
2154 
2155 extern int current_umask(void);
2156 
2157 extern void ihold(struct inode * inode);
2158 extern void iput(struct inode *);
2159 extern int generic_update_time(struct inode *, struct timespec *, int);
2160 
2161 /* /sys/fs */
2162 extern struct kobject *fs_kobj;
2163 
2164 #define MAX_RW_COUNT (INT_MAX & PAGE_MASK)
2165 
2166 #ifdef CONFIG_MANDATORY_FILE_LOCKING
2167 extern int locks_mandatory_locked(struct file *);
2168 extern int locks_mandatory_area(struct inode *, struct file *, loff_t, loff_t, unsigned char);
2169 
2170 /*
2171  * Candidates for mandatory locking have the setgid bit set
2172  * but no group execute bit -  an otherwise meaningless combination.
2173  */
2174 
2175 static inline int __mandatory_lock(struct inode *ino)
2176 {
2177         return (ino->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID;
2178 }
2179 
2180 /*
2181  * ... and these candidates should be on MS_MANDLOCK mounted fs,
2182  * otherwise these will be advisory locks
2183  */
2184 
2185 static inline int mandatory_lock(struct inode *ino)
2186 {
2187         return IS_MANDLOCK(ino) && __mandatory_lock(ino);
2188 }
2189 
2190 static inline int locks_verify_locked(struct file *file)
2191 {
2192         if (mandatory_lock(locks_inode(file)))
2193                 return locks_mandatory_locked(file);
2194         return 0;
2195 }
2196 
2197 static inline int locks_verify_truncate(struct inode *inode,
2198                                     struct file *f,
2199                                     loff_t size)
2200 {
2201         if (!inode->i_flctx || !mandatory_lock(inode))
2202                 return 0;
2203 
2204         if (size < inode->i_size) {
2205                 return locks_mandatory_area(inode, f, size, inode->i_size - 1,
2206                                 F_WRLCK);
2207         } else {
2208                 return locks_mandatory_area(inode, f, inode->i_size, size - 1,
2209                                 F_WRLCK);
2210         }
2211 }
2212 
2213 #else /* !CONFIG_MANDATORY_FILE_LOCKING */
2214 
2215 static inline int locks_mandatory_locked(struct file *file)
2216 {
2217         return 0;
2218 }
2219 
2220 static inline int locks_mandatory_area(struct inode *inode, struct file *filp,
2221                                        loff_t start, loff_t end, unsigned char type)
2222 {
2223         return 0;
2224 }
2225 
2226 static inline int __mandatory_lock(struct inode *inode)
2227 {
2228         return 0;
2229 }
2230 
2231 static inline int mandatory_lock(struct inode *inode)
2232 {
2233         return 0;
2234 }
2235 
2236 static inline int locks_verify_locked(struct file *file)
2237 {
2238         return 0;
2239 }
2240 
2241 static inline int locks_verify_truncate(struct inode *inode, struct file *filp,
2242                                         size_t size)
2243 {
2244         return 0;
2245 }
2246 
2247 #endif /* CONFIG_MANDATORY_FILE_LOCKING */
2248 
2249 
2250 #ifdef CONFIG_FILE_LOCKING
2251 static inline int break_lease(struct inode *inode, unsigned int mode)
2252 {
2253         /*
2254          * Since this check is lockless, we must ensure that any refcounts
2255          * taken are done before checking i_flctx->flc_lease. Otherwise, we
2256          * could end up racing with tasks trying to set a new lease on this
2257          * file.
2258          */
2259         smp_mb();
2260         if (inode->i_flctx && !list_empty_careful(&inode->i_flctx->flc_lease))
2261                 return __break_lease(inode, mode, FL_LEASE);
2262         return 0;
2263 }
2264 
2265 static inline int break_deleg(struct inode *inode, unsigned int mode)
2266 {
2267         /*
2268          * Since this check is lockless, we must ensure that any refcounts
2269          * taken are done before checking i_flctx->flc_lease. Otherwise, we
2270          * could end up racing with tasks trying to set a new lease on this
2271          * file.
2272          */
2273         smp_mb();
2274         if (inode->i_flctx && !list_empty_careful(&inode->i_flctx->flc_lease))
2275                 return __break_lease(inode, mode, FL_DELEG);
2276         return 0;
2277 }
2278 
2279 static inline int try_break_deleg(struct inode *inode, struct inode **delegated_inode)
2280 {
2281         int ret;
2282 
2283         ret = break_deleg(inode, O_WRONLY|O_NONBLOCK);
2284         if (ret == -EWOULDBLOCK && delegated_inode) {
2285                 *delegated_inode = inode;
2286                 ihold(inode);
2287         }
2288         return ret;
2289 }
2290 
2291 static inline int break_deleg_wait(struct inode **delegated_inode)
2292 {
2293         int ret;
2294 
2295         ret = break_deleg(*delegated_inode, O_WRONLY);
2296         iput(*delegated_inode);
2297         *delegated_inode = NULL;
2298         return ret;
2299 }
2300 
2301 static inline int break_layout(struct inode *inode, bool wait)
2302 {
2303         smp_mb();
2304         if (inode->i_flctx && !list_empty_careful(&inode->i_flctx->flc_lease))
2305                 return __break_lease(inode,
2306                                 wait ? O_WRONLY : O_WRONLY | O_NONBLOCK,
2307                                 FL_LAYOUT);
2308         return 0;
2309 }
2310 
2311 #else /* !CONFIG_FILE_LOCKING */
2312 static inline int break_lease(struct inode *inode, unsigned int mode)
2313 {
2314         return 0;
2315 }
2316 
2317 static inline int break_deleg(struct inode *inode, unsigned int mode)
2318 {
2319         return 0;
2320 }
2321 
2322 static inline int try_break_deleg(struct inode *inode, struct inode **delegated_inode)
2323 {
2324         return 0;
2325 }
2326 
2327 static inline int break_deleg_wait(struct inode **delegated_inode)
2328 {
2329         BUG();
2330         return 0;
2331 }
2332 
2333 static inline int break_layout(struct inode *inode, bool wait)
2334 {
2335         return 0;
2336 }
2337 
2338 #endif /* CONFIG_FILE_LOCKING */
2339 
2340 /* fs/open.c */
2341 struct audit_names;
2342 struct filename {
2343         const char              *name;  /* pointer to actual string */
2344         const __user char       *uptr;  /* original userland pointer */
2345         struct audit_names      *aname;
2346         int                     refcnt;
2347         const char              iname[];
2348 };
2349 
2350 extern long vfs_truncate(const struct path *, loff_t);
2351 extern int do_truncate(struct dentry *, loff_t start, unsigned int time_attrs,
2352                        struct file *filp);
2353 extern int vfs_fallocate(struct file *file, int mode, loff_t offset,
2354                         loff_t len);
2355 extern long do_sys_open(int dfd, const char __user *filename, int flags,
2356                         umode_t mode);
2357 extern struct file *file_open_name(struct filename *, int, umode_t);
2358 extern struct file *filp_open(const char *, int, umode_t);
2359 extern struct file *file_open_root(struct dentry *, struct vfsmount *,
2360                                    const char *, int, umode_t);
2361 extern struct file * dentry_open(const struct path *, int, const struct cred *);
2362 extern int filp_close(struct file *, fl_owner_t id);
2363 
2364 extern struct filename *getname_flags(const char __user *, int, int *);
2365 extern struct filename *getname(const char __user *);
2366 extern struct filename *getname_kernel(const char *);
2367 extern void putname(struct filename *name);
2368 
2369 enum {
2370         FILE_CREATED = 1,
2371         FILE_OPENED = 2
2372 };
2373 extern int finish_open(struct file *file, struct dentry *dentry,
2374                         int (*open)(struct inode *, struct file *),
2375                         int *opened);
2376 extern int finish_no_open(struct file *file, struct dentry *dentry);
2377 
2378 /* fs/ioctl.c */
2379 
2380 extern int ioctl_preallocate(struct file *filp, void __user *argp);
2381 
2382 /* fs/dcache.c */
2383 extern void __init vfs_caches_init_early(void);
2384 extern void __init vfs_caches_init(void);
2385 
2386 extern struct kmem_cache *names_cachep;
2387 
2388 #define __getname()             kmem_cache_alloc(names_cachep, GFP_KERNEL)
2389 #define __putname(name)         kmem_cache_free(names_cachep, (void *)(name))
2390 
2391 #ifdef CONFIG_BLOCK
2392 extern int register_blkdev(unsigned int, const char *);
2393 extern void unregister_blkdev(unsigned int, const char *);
2394 extern void bdev_unhash_inode(dev_t dev);
2395 extern struct block_device *bdget(dev_t);
2396 extern struct block_device *bdgrab(struct block_device *bdev);
2397 extern void bd_set_size(struct block_device *, loff_t size);
2398 extern void bd_forget(struct inode *inode);
2399 extern void bdput(struct block_device *);
2400 extern void invalidate_bdev(struct block_device *);
2401 extern void iterate_bdevs(void (*)(struct block_device *, void *), void *);
2402 extern int sync_blockdev(struct block_device *bdev);
2403 extern void kill_bdev(struct block_device *);
2404 extern struct super_block *freeze_bdev(struct block_device *);
2405 extern void emergency_thaw_all(void);
2406 extern int thaw_bdev(struct block_device *bdev, struct super_block *sb);
2407 extern int fsync_bdev(struct block_device *);
2408 
2409 extern struct super_block *blockdev_superblock;
2410 
2411 static inline bool sb_is_blkdev_sb(struct super_block *sb)
2412 {
2413         return sb == blockdev_superblock;
2414 }
2415 #else
2416 static inline void bd_forget(struct inode *inode) {}
2417 static inline int sync_blockdev(struct block_device *bdev) { return 0; }
2418 static inline void kill_bdev(struct block_device *bdev) {}
2419 static inline void invalidate_bdev(struct block_device *bdev) {}
2420 
2421 static inline struct super_block *freeze_bdev(struct block_device *sb)
2422 {
2423         return NULL;
2424 }
2425 
2426 static inline int thaw_bdev(struct block_device *bdev, struct super_block *sb)
2427 {
2428         return 0;
2429 }
2430 
2431 static inline void iterate_bdevs(void (*f)(struct block_device *, void *), void *arg)
2432 {
2433 }
2434 
2435 static inline bool sb_is_blkdev_sb(struct super_block *sb)
2436 {
2437         return false;
2438 }
2439 #endif
2440 extern int sync_filesystem(struct super_block *);
2441 extern const struct file_operations def_blk_fops;
2442 extern const struct file_operations def_chr_fops;
2443 #ifdef CONFIG_BLOCK
2444 extern int ioctl_by_bdev(struct block_device *, unsigned, unsigned long);
2445 extern int blkdev_ioctl(struct block_device *, fmode_t, unsigned, unsigned long);
2446 extern long compat_blkdev_ioctl(struct file *, unsigned, unsigned long);
2447 extern int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder);
2448 extern struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
2449                                                void *holder);
2450 extern struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode,
2451                                               void *holder);
2452 extern void blkdev_put(struct block_device *bdev, fmode_t mode);
2453 extern int __blkdev_reread_part(struct block_device *bdev);
2454 extern int blkdev_reread_part(struct block_device *bdev);
2455 
2456 #ifdef CONFIG_SYSFS
2457 extern int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk);
2458 extern void bd_unlink_disk_holder(struct block_device *bdev,
2459                                   struct gendisk *disk);
2460 #else
2461 static inline int bd_link_disk_holder(struct block_device *bdev,
2462                                       struct gendisk *disk)
2463 {
2464         return 0;
2465 }
2466 static inline void bd_unlink_disk_holder(struct block_device *bdev,
2467                                          struct gendisk *disk)
2468 {
2469 }
2470 #endif
2471 #endif
2472 
2473 /* fs/char_dev.c */
2474 #define CHRDEV_MAJOR_HASH_SIZE  255
2475 /* Marks the bottom of the first segment of free char majors */
2476 #define CHRDEV_MAJOR_DYN_END 234
2477 extern int alloc_chrdev_region(dev_t *, unsigned, unsigned, const char *);
2478 extern int register_chrdev_region(dev_t, unsigned, const char *);
2479 extern int __register_chrdev(unsigned int major, unsigned int baseminor,
2480                              unsigned int count, const char *name,
2481                              const struct file_operations *fops);
2482 extern void __unregister_chrdev(unsigned int major, unsigned int baseminor,
2483                                 unsigned int count, const char *name);
2484 extern void unregister_chrdev_region(dev_t, unsigned);
2485 extern void chrdev_show(struct seq_file *,off_t);
2486 
2487 static inline int register_chrdev(unsigned int major, const char *name,
2488                                   const struct file_operations *fops)
2489 {
2490         return __register_chrdev(major, 0, 256, name, fops);
2491 }
2492 
2493 static inline void unregister_chrdev(unsigned int major, const char *name)
2494 {
2495         __unregister_chrdev(major, 0, 256, name);
2496 }
2497 
2498 /* fs/block_dev.c */
2499 #define BDEVNAME_SIZE   32      /* Largest string for a blockdev identifier */
2500 #define BDEVT_SIZE      10      /* Largest string for MAJ:MIN for blkdev */
2501 
2502 #ifdef CONFIG_BLOCK
2503 #define BLKDEV_MAJOR_HASH_SIZE  255
2504 extern const char *__bdevname(dev_t, char *buffer);
2505 extern const char *bdevname(struct block_device *bdev, char *buffer);
2506 extern struct block_device *lookup_bdev(const char *);
2507 extern void blkdev_show(struct seq_file *,off_t);
2508 
2509 #else
2510 #define BLKDEV_MAJOR_HASH_SIZE  0
2511 #endif
2512 
2513 extern void init_special_inode(struct inode *, umode_t, dev_t);
2514 
2515 /* Invalid inode operations -- fs/bad_inode.c */
2516 extern void make_bad_inode(struct inode *);
2517 extern bool is_bad_inode(struct inode *);
2518 
2519 #ifdef CONFIG_BLOCK
2520 extern void check_disk_size_change(struct gendisk *disk,
2521                                    struct block_device *bdev);
2522 extern int revalidate_disk(struct gendisk *);
2523 extern int check_disk_change(struct block_device *);
2524 extern int __invalidate_device(struct block_device *, bool);
2525 extern int invalidate_partition(struct gendisk *, int);
2526 #endif
2527 unsigned long invalidate_mapping_pages(struct address_space *mapping,
2528                                         pgoff_t start, pgoff_t end);
2529 
2530 static inline void invalidate_remote_inode(struct inode *inode)
2531 {
2532         if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
2533             S_ISLNK(inode->i_mode))
2534                 invalidate_mapping_pages(inode->i_mapping, 0, -1);
2535 }
2536 extern int invalidate_inode_pages2(struct address_space *mapping);
2537 extern int invalidate_inode_pages2_range(struct address_space *mapping,
2538                                          pgoff_t start, pgoff_t end);
2539 extern int write_inode_now(struct inode *, int);
2540 extern int filemap_fdatawrite(struct address_space *);
2541 extern int filemap_flush(struct address_space *);
2542 extern int filemap_fdatawait(struct address_space *);
2543 extern int filemap_fdatawait_keep_errors(struct address_space *mapping);
2544 extern int filemap_fdatawait_range(struct address_space *, loff_t lstart,
2545                                    loff_t lend);
2546 extern bool filemap_range_has_page(struct address_space *, loff_t lstart,
2547                                   loff_t lend);
2548 extern int filemap_write_and_wait(struct address_space *mapping);
2549 extern int filemap_write_and_wait_range(struct address_space *mapping,
2550                                         loff_t lstart, loff_t lend);
2551 extern int __filemap_fdatawrite_range(struct address_space *mapping,
2552                                 loff_t start, loff_t end, int sync_mode);
2553 extern int filemap_fdatawrite_range(struct address_space *mapping,
2554                                 loff_t start, loff_t end);
2555 extern int filemap_check_errors(struct address_space *mapping);
2556 
2557 extern void __filemap_set_wb_err(struct address_space *mapping, int err);
2558 extern int __must_check file_check_and_advance_wb_err(struct file *file);
2559 extern int __must_check file_write_and_wait_range(struct file *file,
2560                                                 loff_t start, loff_t end);
2561 
2562 /**
2563  * filemap_set_wb_err - set a writeback error on an address_space
2564  * @mapping: mapping in which to set writeback error
2565  * @err: error to be set in mapping
2566  *
2567  * When writeback fails in some way, we must record that error so that
2568  * userspace can be informed when fsync and the like are called.  We endeavor
2569  * to report errors on any file that was open at the time of the error.  Some
2570  * internal callers also need to know when writeback errors have occurred.
2571  *
2572  * When a writeback error occurs, most filesystems will want to call
2573  * filemap_set_wb_err to record the error in the mapping so that it will be
2574  * automatically reported whenever fsync is called on the file.
2575  *
2576  * FIXME: mention FS_* flag here?
2577  */
2578 static inline void filemap_set_wb_err(struct address_space *mapping, int err)
2579 {
2580         /* Fastpath for common case of no error */
2581         if (unlikely(err))
2582                 __filemap_set_wb_err(mapping, err);
2583 }
2584 
2585 /**
2586  * filemap_check_wb_error - has an error occurred since the mark was sampled?
2587  * @mapping: mapping to check for writeback errors
2588  * @since: previously-sampled errseq_t
2589  *
2590  * Grab the errseq_t value from the mapping, and see if it has changed "since"
2591  * the given value was sampled.
2592  *
2593  * If it has then report the latest error set, otherwise return 0.
2594  */
2595 static inline int filemap_check_wb_err(struct address_space *mapping,
2596                                         errseq_t since)
2597 {
2598         return errseq_check(&mapping->wb_err, since);
2599 }
2600 
2601 /**
2602  * filemap_sample_wb_err - sample the current errseq_t to test for later errors
2603  * @mapping: mapping to be sampled
2604  *
2605  * Writeback errors are always reported relative to a particular sample point
2606  * in the past. This function provides those sample points.
2607  */
2608 static inline errseq_t filemap_sample_wb_err(struct address_space *mapping)
2609 {
2610         return errseq_sample(&mapping->wb_err);
2611 }
2612 
2613 extern int vfs_fsync_range(struct file *file, loff_t start, loff_t end,
2614                            int datasync);
2615 extern int vfs_fsync(struct file *file, int datasync);
2616 
2617 /*
2618  * Sync the bytes written if this was a synchronous write.  Expect ki_pos
2619  * to already be updated for the write, and will return either the amount
2620  * of bytes passed in, or an error if syncing the file failed.
2621  */
2622 static inline ssize_t generic_write_sync(struct kiocb *iocb, ssize_t count)
2623 {
2624         if (iocb->ki_flags & IOCB_DSYNC) {
2625                 int ret = vfs_fsync_range(iocb->ki_filp,
2626                                 iocb->ki_pos - count, iocb->ki_pos - 1,
2627                                 (iocb->ki_flags & IOCB_SYNC) ? 0 : 1);
2628                 if (ret)
2629                         return ret;
2630         }
2631 
2632         return count;
2633 }
2634 
2635 extern void emergency_sync(void);
2636 extern void emergency_remount(void);
2637 #ifdef CONFIG_BLOCK
2638 extern sector_t bmap(struct inode *, sector_t);
2639 #endif
2640 extern int notify_change(struct dentry *, struct iattr *, struct inode **);
2641 extern int inode_permission(struct inode *, int);
2642 extern int __inode_permission(struct inode *, int);
2643 extern int generic_permission(struct inode *, int);
2644 extern int __check_sticky(struct inode *dir, struct inode *inode);
2645 
2646 static inline bool execute_ok(struct inode *inode)
2647 {
2648         return (inode->i_mode & S_IXUGO) || S_ISDIR(inode->i_mode);
2649 }
2650 
2651 static inline void file_start_write(struct file *file)
2652 {
2653         if (!S_ISREG(file_inode(file)->i_mode))
2654                 return;
2655         __sb_start_write(file_inode(file)->i_sb, SB_FREEZE_WRITE, true);
2656 }
2657 
2658 static inline bool file_start_write_trylock(struct file *file)
2659 {
2660         if (!S_ISREG(file_inode(file)->i_mode))
2661                 return true;
2662         return __sb_start_write(file_inode(file)->i_sb, SB_FREEZE_WRITE, false);
2663 }
2664 
2665 static inline void file_end_write(struct file *file)
2666 {
2667         if (!S_ISREG(file_inode(file)->i_mode))
2668                 return;
2669         __sb_end_write(file_inode(file)->i_sb, SB_FREEZE_WRITE);
2670 }
2671 
2672 static inline int do_clone_file_range(struct file *file_in, loff_t pos_in,
2673                                       struct file *file_out, loff_t pos_out,
2674                                       u64 len)
2675 {
2676         int ret;
2677 
2678         file_start_write(file_out);
2679         ret = vfs_clone_file_range(file_in, pos_in, file_out, pos_out, len);
2680         file_end_write(file_out);
2681 
2682         return ret;
2683 }
2684 
2685 /*
2686  * get_write_access() gets write permission for a file.
2687  * put_write_access() releases this write permission.
2688  * This is used for regular files.
2689  * We cannot support write (and maybe mmap read-write shared) accesses and
2690  * MAP_DENYWRITE mmappings simultaneously. The i_writecount field of an inode
2691  * can have the following values:
2692  * 0: no writers, no VM_DENYWRITE mappings
2693  * < 0: (-i_writecount) vm_area_structs with VM_DENYWRITE set exist
2694  * > 0: (i_writecount) users are writing to the file.
2695  *
2696  * Normally we operate on that counter with atomic_{inc,dec} and it's safe
2697  * except for the cases where we don't hold i_writecount yet. Then we need to
2698  * use {get,deny}_write_access() - these functions check the sign and refuse
2699  * to do the change if sign is wrong.
2700  */
2701 static inline int get_write_access(struct inode *inode)
2702 {
2703         return atomic_inc_unless_negative(&inode->i_writecount) ? 0 : -ETXTBSY;
2704 }
2705 static inline int deny_write_access(struct file *file)
2706 {
2707         struct inode *inode = file_inode(file);
2708         return atomic_dec_unless_positive(&inode->i_writecount) ? 0 : -ETXTBSY;
2709 }
2710 static inline void put_write_access(struct inode * inode)
2711 {
2712         atomic_dec(&inode->i_writecount);
2713 }
2714 static inline void allow_write_access(struct file *file)
2715 {
2716         if (file)
2717                 atomic_inc(&file_inode(file)->i_writecount);
2718 }
2719 static inline bool inode_is_open_for_write(const struct inode *inode)
2720 {
2721         return atomic_read(&inode->i_writecount) > 0;
2722 }
2723 
2724 #ifdef CONFIG_IMA
2725 static inline void i_readcount_dec(struct inode *inode)
2726 {
2727         BUG_ON(!atomic_read(&inode->i_readcount));
2728         atomic_dec(&inode->i_readcount);
2729 }
2730 static inline void i_readcount_inc(struct inode *inode)
2731 {
2732         atomic_inc(&inode->i_readcount);
2733 }
2734 #else
2735 static inline void i_readcount_dec(struct inode *inode)
2736 {
2737         return;
2738 }
2739 static inline void i_readcount_inc(struct inode *inode)
2740 {
2741         return;
2742 }
2743 #endif
2744 extern int do_pipe_flags(int *, int);
2745 
2746 #define __kernel_read_file_id(id) \
2747         id(UNKNOWN, unknown)            \
2748         id(FIRMWARE, firmware)          \
2749         id(FIRMWARE_PREALLOC_BUFFER, firmware)  \
2750         id(MODULE, kernel-module)               \
2751         id(KEXEC_IMAGE, kexec-image)            \
2752         id(KEXEC_INITRAMFS, kexec-initramfs)    \
2753         id(POLICY, security-policy)             \
2754         id(MAX_ID, )
2755 
2756 #define __fid_enumify(ENUM, dummy) READING_ ## ENUM,
2757 #define __fid_stringify(dummy, str) #str,
2758 
2759 enum kernel_read_file_id {
2760         __kernel_read_file_id(__fid_enumify)
2761 };
2762 
2763 static const char * const kernel_read_file_str[] = {
2764         __kernel_read_file_id(__fid_stringify)
2765 };
2766 
2767 static inline const char *kernel_read_file_id_str(enum kernel_read_file_id id)
2768 {
2769         if ((unsigned)id >= READING_MAX_ID)
2770                 return kernel_read_file_str[READING_UNKNOWN];
2771 
2772         return kernel_read_file_str[id];
2773 }
2774 
2775 extern int kernel_read(struct file *, loff_t, char *, unsigned long);
2776 extern int kernel_read_file(struct file *, void **, loff_t *, loff_t,
2777                             enum kernel_read_file_id);
2778 extern int kernel_read_file_from_path(char *, void **, loff_t *, loff_t,
2779                                       enum kernel_read_file_id);
2780 extern int kernel_read_file_from_fd(int, void **, loff_t *, loff_t,
2781                                     enum kernel_read_file_id);
2782 extern ssize_t kernel_write(struct file *, const char *, size_t, loff_t);
2783 extern ssize_t __kernel_write(struct file *, const char *, size_t, loff_t *);
2784 extern struct file * open_exec(const char *);
2785  
2786 /* fs/dcache.c -- generic fs support functions */
2787 extern bool is_subdir(struct dentry *, struct dentry *);
2788 extern bool path_is_under(const struct path *, const struct path *);
2789 
2790 extern char *file_path(struct file *, char *, int);
2791 
2792 #include <linux/err.h>
2793 
2794 /* needed for stackable file system support */
2795 extern loff_t default_llseek(struct file *file, loff_t offset, int whence);
2796 
2797 extern loff_t vfs_llseek(struct file *file, loff_t offset, int whence);
2798 
2799 extern int inode_init_always(struct super_block *, struct inode *);
2800 extern void inode_init_once(struct inode *);
2801 extern void address_space_init_once(struct address_space *mapping);
2802 extern struct inode * igrab(struct inode *);
2803 extern ino_t iunique(struct super_block *, ino_t);
2804 extern int inode_needs_sync(struct inode *inode);
2805 extern int generic_delete_inode(struct inode *inode);
2806 static inline int generic_drop_inode(struct inode *inode)
2807 {
2808         return !inode->i_nlink || inode_unhashed(inode);
2809 }
2810 
2811 extern struct inode *ilookup5_nowait(struct super_block *sb,
2812                 unsigned long hashval, int (*test)(struct inode *, void *),
2813                 void *data);
2814 extern struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
2815                 int (*test)(struct inode *, void *), void *data);
2816 extern struct inode *ilookup(struct super_block *sb, unsigned long ino);
2817 
2818 extern struct inode * iget5_locked(struct super_block *, unsigned long, int (*test)(struct inode *, void *), int (*set)(struct inode *, void *), void *);
2819 extern struct inode * iget_locked(struct super_block *, unsigned long);
2820 extern struct inode *find_inode_nowait(struct super_block *,
2821                                        unsigned long,
2822                                        int (*match)(struct inode *,
2823                                                     unsigned long, void *),
2824                                        void *data);
2825 extern int insert_inode_locked4(struct inode *, unsigned long, int (*test)(struct inode *, void *), void *);
2826 extern int insert_inode_locked(struct inode *);
2827 #ifdef CONFIG_DEBUG_LOCK_ALLOC
2828 extern void lockdep_annotate_inode_mutex_key(struct inode *inode);
2829 #else
2830 static inline void lockdep_annotate_inode_mutex_key(struct inode *inode) { };
2831 #endif
2832 extern void unlock_new_inode(struct inode *);
2833 extern unsigned int get_next_ino(void);
2834 extern void evict_inodes(struct super_block *sb);
2835 
2836 extern void __iget(struct inode * inode);
2837 extern void iget_failed(struct inode *);
2838 extern void clear_inode(struct inode *);
2839 extern void __destroy_inode(struct inode *);
2840 extern struct inode *new_inode_pseudo(struct super_block *sb);
2841 extern struct inode *new_inode(struct super_block *sb);
2842 extern void free_inode_nonrcu(struct inode *inode);
2843 extern int should_remove_suid(struct dentry *);
2844 extern int file_remove_privs(struct file *);
2845 
2846 extern void __insert_inode_hash(struct inode *, unsigned long hashval);
2847 static inline void insert_inode_hash(struct inode *inode)
2848 {
2849         __insert_inode_hash(inode, inode->i_ino);
2850 }
2851 
2852 extern void __remove_inode_hash(struct inode *);
2853 static inline void remove_inode_hash(struct inode *inode)
2854 {
2855         if (!inode_unhashed(inode) && !hlist_fake(&inode->i_hash))
2856                 __remove_inode_hash(inode);
2857 }
2858 
2859 extern void inode_sb_list_add(struct inode *inode);
2860 
2861 #ifdef CONFIG_BLOCK
2862 extern int bdev_read_only(struct block_device *);
2863 #endif
2864 extern int set_blocksize(struct block_device *, int);
2865 extern int sb_set_blocksize(struct super_block *, int);
2866 extern int sb_min_blocksize(struct super_block *, int);
2867 
2868 extern int generic_file_mmap(struct file *, struct vm_area_struct *);
2869 extern int generic_file_readonly_mmap(struct file *, struct vm_area_struct *);
2870 extern ssize_t generic_write_checks(struct kiocb *, struct iov_iter *);
2871 extern ssize_t generic_file_read_iter(struct kiocb *, struct iov_iter *);
2872 extern ssize_t __generic_file_write_iter(struct kiocb *, struct iov_iter *);
2873 extern ssize_t generic_file_write_iter(struct kiocb *, struct iov_iter *);
2874 extern ssize_t generic_file_direct_write(struct kiocb *, struct iov_iter *);
2875 extern ssize_t generic_perform_write(struct file *, struct iov_iter *, loff_t);
2876 
2877 ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos,
2878                 int flags);
2879 ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos,
2880                 int flags);
2881 
2882 /* fs/block_dev.c */
2883 extern ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to);
2884 extern ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from);
2885 extern int blkdev_fsync(struct file *filp, loff_t start, loff_t end,
2886                         int datasync);
2887 extern void block_sync_page(struct page *page);
2888 
2889 /* fs/splice.c */
2890 extern ssize_t generic_file_splice_read(struct file *, loff_t *,
2891                 struct pipe_inode_info *, size_t, unsigned int);
2892 extern ssize_t iter_file_splice_write(struct pipe_inode_info *,
2893                 struct file *, loff_t *, size_t, unsigned int);
2894 extern ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe,
2895                 struct file *out, loff_t *, size_t len, unsigned int flags);
2896 extern long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
2897                 loff_t *opos, size_t len, unsigned int flags);
2898 
2899 
2900 extern void
2901 file_ra_state_init(struct file_ra_state *ra, struct address_space *mapping);
2902 extern loff_t noop_llseek(struct file *file, loff_t offset, int whence);
2903 extern loff_t no_llseek(struct file *file, loff_t offset, int whence);
2904 extern loff_t vfs_setpos(struct file *file, loff_t offset, loff_t maxsize);
2905 extern loff_t generic_file_llseek(struct file *file, loff_t offset, int whence);
2906 extern loff_t generic_file_llseek_size(struct file *file, loff_t offset,
2907                 int whence, loff_t maxsize, loff_t eof);
2908 extern loff_t fixed_size_llseek(struct file *file, loff_t offset,
2909                 int whence, loff_t size);
2910 extern loff_t no_seek_end_llseek_size(struct file *, loff_t, int, loff_t);
2911 extern loff_t no_seek_end_llseek(struct file *, loff_t, int);
2912 extern int generic_file_open(struct inode * inode, struct file * filp);
2913 extern int nonseekable_open(struct inode * inode, struct file * filp);
2914 
2915 #ifdef CONFIG_BLOCK
2916 typedef void (dio_submit_t)(struct bio *bio, struct inode *inode,
2917                             loff_t file_offset);
2918 
2919 enum {
2920         /* need locking between buffered and direct access */
2921         DIO_LOCKING     = 0x01,
2922 
2923         /* filesystem does not support filling holes */
2924         DIO_SKIP_HOLES  = 0x02,
2925 
2926         /* filesystem can handle aio writes beyond i_size */
2927         DIO_ASYNC_EXTEND = 0x04,
2928 
2929         /* inode/fs/bdev does not need truncate protection */
2930         DIO_SKIP_DIO_COUNT = 0x08,
2931 };
2932 
2933 void dio_end_io(struct bio *bio);
2934 
2935 ssize_t __blockdev_direct_IO(struct kiocb *iocb, struct inode *inode,
2936                              struct block_device *bdev, struct iov_iter *iter,
2937                              get_block_t get_block,
2938                              dio_iodone_t end_io, dio_submit_t submit_io,
2939                              int flags);
2940 
2941 static inline ssize_t blockdev_direct_IO(struct kiocb *iocb,
2942                                          struct inode *inode,
2943                                          struct iov_iter *iter,
2944                                          get_block_t get_block)
2945 {
2946         return __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev, iter,
2947                         get_block, NULL, NULL, DIO_LOCKING | DIO_SKIP_HOLES);
2948 }
2949 #endif
2950 
2951 void inode_dio_wait(struct inode *inode);
2952 
2953 /*
2954  * inode_dio_begin - signal start of a direct I/O requests
2955  * @inode: inode the direct I/O happens on
2956  *
2957  * This is called once we've finished processing a direct I/O request,
2958  * and is used to wake up callers waiting for direct I/O to be quiesced.
2959  */
2960 static inline void inode_dio_begin(struct inode *inode)
2961 {
2962         atomic_inc(&inode->i_dio_count);
2963 }
2964 
2965 /*
2966  * inode_dio_end - signal finish of a direct I/O requests
2967  * @inode: inode the direct I/O happens on
2968  *
2969  * This is called once we've finished processing a direct I/O request,
2970  * and is used to wake up callers waiting for direct I/O to be quiesced.
2971  */
2972 static inline void inode_dio_end(struct inode *inode)
2973 {
2974         if (atomic_dec_and_test(&inode->i_dio_count))
2975                 wake_up_bit(&inode->i_state, __I_DIO_WAKEUP);
2976 }
2977 
2978 extern void inode_set_flags(struct inode *inode, unsigned int flags,
2979                             unsigned int mask);
2980 
2981 extern const struct file_operations generic_ro_fops;
2982 
2983 #define special_file(m) (S_ISCHR(m)||S_ISBLK(m)||S_ISFIFO(m)||S_ISSOCK(m))
2984 
2985 extern int readlink_copy(char __user *, int, const char *);
2986 extern int page_readlink(struct dentry *, char __user *, int);
2987 extern const char *page_get_link(struct dentry *, struct inode *,
2988                                  struct delayed_call *);
2989 extern void page_put_link(void *);
2990 extern int __page_symlink(struct inode *inode, const char *symname, int len,
2991                 int nofs);
2992 extern int page_symlink(struct inode *inode, const char *symname, int len);
2993 extern const struct inode_operations page_symlink_inode_operations;
2994 extern void kfree_link(void *);
2995 extern void generic_fillattr(struct inode *, struct kstat *);
2996 extern int vfs_getattr_nosec(const struct path *, struct kstat *, u32, unsigned int);
2997 extern int vfs_getattr(const struct path *, struct kstat *, u32, unsigned int);
2998 void __inode_add_bytes(struct inode *inode, loff_t bytes);
2999 void inode_add_bytes(struct inode *inode, loff_t bytes);
3000 void __inode_sub_bytes(struct inode *inode, loff_t bytes);
3001 void inode_sub_bytes(struct inode *inode, loff_t bytes);
3002 loff_t inode_get_bytes(struct inode *inode);
3003 void inode_set_bytes(struct inode *inode, loff_t bytes);
3004 const char *simple_get_link(struct dentry *, struct inode *,
3005                             struct delayed_call *);
3006 extern const struct inode_operations simple_symlink_inode_operations;
3007 
3008 extern int iterate_dir(struct file *, struct dir_context *);
3009 
3010 extern int vfs_statx(int, const char __user *, int, struct kstat *, u32);
3011 extern int vfs_statx_fd(unsigned int, struct kstat *, u32, unsigned int);
3012 
3013 static inline int vfs_stat(const char __user *filename, struct kstat *stat)
3014 {
3015         return vfs_statx(AT_FDCWD, filename, AT_NO_AUTOMOUNT,
3016                          stat, STATX_BASIC_STATS);
3017 }
3018 static inline int vfs_lstat(const char __user *name, struct kstat *stat)
3019 {
3020         return vfs_statx(AT_FDCWD, name, AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT,
3021                          stat, STATX_BASIC_STATS);
3022 }
3023 static inline int vfs_fstatat(int dfd, const char __user *filename,
3024                               struct kstat *stat, int flags)
3025 {
3026         return vfs_statx(dfd, filename, flags | AT_NO_AUTOMOUNT,
3027                          stat, STATX_BASIC_STATS);
3028 }
3029 static inline int vfs_fstat(int fd, struct kstat *stat)
3030 {
3031         return vfs_statx_fd(fd, stat, STATX_BASIC_STATS, 0);
3032 }
3033 
3034 
3035 extern const char *vfs_get_link(struct dentry *, struct delayed_call *);
3036 extern int vfs_readlink(struct dentry *, char __user *, int);
3037 
3038 extern int __generic_block_fiemap(struct inode *inode,
3039                                   struct fiemap_extent_info *fieinfo,
3040                                   loff_t start, loff_t len,
3041                                   get_block_t *get_block);
3042 extern int generic_block_fiemap(struct inode *inode,
3043                                 struct fiemap_extent_info *fieinfo, u64 start,
3044                                 u64 len, get_block_t *get_block);
3045 
3046 extern struct file_system_type *get_filesystem(struct file_system_type *fs);
3047 extern void put_filesystem(struct file_system_type *fs);
3048 extern struct file_system_type *get_fs_type(const char *name);
3049 extern struct super_block *get_super(struct block_device *);
3050 extern struct super_block *get_super_thawed(struct block_device *);
3051 extern struct super_block *get_super_exclusive_thawed(struct block_device *bdev);
3052 extern struct super_block *get_active_super(struct block_device *bdev);
3053 extern void drop_super(struct super_block *sb);
3054 extern void drop_super_exclusive(struct super_block *sb);
3055 extern void iterate_supers(void (*)(struct super_block *, void *), void *);
3056 extern void iterate_supers_type(struct file_system_type *,
3057                                 void (*)(struct super_block *, void *), void *);
3058 
3059 extern int dcache_dir_open(struct inode *, struct file *);
3060 extern int dcache_dir_close(struct inode *, struct file *);
3061 extern loff_t dcache_dir_lseek(struct file *, loff_t, int);
3062 extern int dcache_readdir(struct file *, struct dir_context *);
3063 extern int simple_setattr(struct dentry *, struct iattr *);
3064 extern int simple_getattr(const struct path *, struct kstat *, u32, unsigned int);
3065 extern int simple_statfs(struct dentry *, struct kstatfs *);
3066 extern int simple_open(struct inode *inode, struct file *file);
3067 extern int simple_link(struct dentry *, struct inode *, struct dentry *);
3068 extern int simple_unlink(struct inode *, struct dentry *);
3069 extern int simple_rmdir(struct inode *, struct dentry *);
3070 extern int simple_rename(struct inode *, struct dentry *,
3071                          struct inode *, struct dentry *, unsigned int);
3072 extern int noop_fsync(struct file *, loff_t, loff_t, int);
3073 extern int simple_empty(struct dentry *);
3074 extern int simple_readpage(struct file *file, struct page *page);
3075 extern int simple_write_begin(struct file *file, struct address_space *mapping,
3076                         loff_t pos, unsigned len, unsigned flags,
3077                         struct page **pagep, void **fsdata);
3078 extern int simple_write_end(struct file *file, struct address_space *mapping,
3079                         loff_t pos, unsigned len, unsigned copied,
3080                         struct page *page, void *fsdata);
3081 extern int always_delete_dentry(const struct dentry *);
3082 extern struct inode *alloc_anon_inode(struct super_block *);
3083 extern int simple_nosetlease(struct file *, long, struct file_lock **, void **);
3084 extern const struct dentry_operations simple_dentry_operations;
3085 
3086 extern struct dentry *simple_lookup(struct inode *, struct dentry *, unsigned int flags);
3087 extern ssize_t generic_read_dir(struct file *, char __user *, size_t, loff_t *);
3088 extern const struct file_operations simple_dir_operations;
3089 extern const struct inode_operations simple_dir_inode_operations;
3090 extern void make_empty_dir_inode(struct inode *inode);
3091 extern bool is_empty_dir_inode(struct inode *inode);
3092 struct tree_descr { const char *name; const struct file_operations *ops; int mode; };
3093 struct dentry *d_alloc_name(struct dentry *, const char *);
3094 extern int simple_fill_super(struct super_block *, unsigned long,
3095                              const struct tree_descr *);
3096 extern int simple_pin_fs(struct file_system_type *, struct vfsmount **mount, int *count);
3097 extern void simple_release_fs(struct vfsmount **mount, int *count);
3098 
3099 extern ssize_t simple_read_from_buffer(void __user *to, size_t count,
3100                         loff_t *ppos, const void *from, size_t available);
3101 extern ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos,
3102                 const void __user *from, size_t count);
3103 
3104 extern int __generic_file_fsync(struct file *, loff_t, loff_t, int);
3105 extern int generic_file_fsync(struct file *, loff_t, loff_t, int);
3106 
3107 extern int generic_check_addressable(unsigned, u64);
3108 
3109 #ifdef CONFIG_MIGRATION
3110 extern int buffer_migrate_page(struct address_space *,
3111                                 struct page *, struct page *,
3112                                 enum migrate_mode);
3113 #else
3114 #define buffer_migrate_page NULL
3115 #endif
3116 
3117 extern int setattr_prepare(struct dentry *, struct iattr *);
3118 extern int inode_newsize_ok(const struct inode *, loff_t offset);
3119 extern void setattr_copy(struct inode *inode, const struct iattr *attr);
3120 
3121 extern int file_update_time(struct file *file);
3122 
3123 static inline bool io_is_direct(struct file *filp)
3124 {
3125         return (filp->f_flags & O_DIRECT) || IS_DAX(filp->f_mapping->host);
3126 }
3127 
3128 static inline bool vma_is_dax(struct vm_area_struct *vma)
3129 {
3130         return vma->vm_file && IS_DAX(vma->vm_file->f_mapping->host);
3131 }
3132 
3133 static inline int iocb_flags(struct file *file)
3134 {
3135         int res = 0;
3136         if (file->f_flags & O_APPEND)
3137                 res |= IOCB_APPEND;
3138         if (io_is_direct(file))
3139                 res |= IOCB_DIRECT;
3140         if ((file->f_flags & O_DSYNC) || IS_SYNC(file->f_mapping->host))
3141                 res |= IOCB_DSYNC;
3142         if (file->f_flags & __O_SYNC)
3143                 res |= IOCB_SYNC;
3144         return res;
3145 }
3146 
3147 static inline int kiocb_set_rw_flags(struct kiocb *ki, int flags)
3148 {
3149         if (unlikely(flags & ~RWF_SUPPORTED))
3150                 return -EOPNOTSUPP;
3151 
3152         if (flags & RWF_NOWAIT) {
3153                 if (!(ki->ki_filp->f_mode & FMODE_AIO_NOWAIT))
3154                         return -EOPNOTSUPP;
3155                 ki->ki_flags |= IOCB_NOWAIT;
3156         }
3157         if (flags & RWF_HIPRI)
3158                 ki->ki_flags |= IOCB_HIPRI;
3159         if (flags & RWF_DSYNC)
3160                 ki->ki_flags |= IOCB_DSYNC;
3161         if (flags & RWF_SYNC)
3162                 ki->ki_flags |= (IOCB_DSYNC | IOCB_SYNC);
3163         return 0;
3164 }
3165 
3166 static inline ino_t parent_ino(struct dentry *dentry)
3167 {
3168         ino_t res;
3169 
3170         /*
3171          * Don't strictly need d_lock here? If the parent ino could change
3172          * then surely we'd have a deeper race in the caller?
3173          */
3174         spin_lock(&dentry->d_lock);
3175         res = dentry->d_parent->d_inode->i_ino;
3176         spin_unlock(&dentry->d_lock);
3177         return res;
3178 }
3179 
3180 /* Transaction based IO helpers */
3181 
3182 /*
3183  * An argresp is stored in an allocated page and holds the
3184  * size of the argument or response, along with its content
3185  */
3186 struct simple_transaction_argresp {
3187         ssize_t size;
3188         char data[0];
3189 };
3190 
3191 #define SIMPLE_TRANSACTION_LIMIT (PAGE_SIZE - sizeof(struct simple_transaction_argresp))
3192 
3193 char *simple_transaction_get(struct file *file, const char __user *buf,
3194                                 size_t size);
3195 ssize_t simple_transaction_read(struct file *file, char __user *buf,
3196                                 size_t size, loff_t *pos);
3197 int simple_transaction_release(struct inode *inode, struct file *file);
3198 
3199 void simple_transaction_set(struct file *file, size_t n);
3200 
3201 /*
3202  * simple attribute files
3203  *
3204  * These attributes behave similar to those in sysfs:
3205  *
3206  * Writing to an attribute immediately sets a value, an open file can be
3207  * written to multiple times.
3208  *
3209  * Reading from an attribute creates a buffer from the value that might get
3210  * read with multiple read calls. When the attribute has been read
3211  * completely, no further read calls are possible until the file is opened
3212  * again.
3213  *
3214  * All attributes contain a text representation of a numeric value
3215  * that are accessed with the get() and set() functions.
3216  */
3217 #define DEFINE_SIMPLE_ATTRIBUTE(__fops, __get, __set, __fmt)            \
3218 static int __fops ## _open(struct inode *inode, struct file *file)      \
3219 {                                                                       \
3220         __simple_attr_check_format(__fmt, 0ull);                        \
3221         return simple_attr_open(inode, file, __get, __set, __fmt);      \
3222 }                                                                       \
3223 static const struct file_operations __fops = {                          \
3224         .owner   = THIS_MODULE,                                         \
3225         .open    = __fops ## _open,                                     \
3226         .release = simple_attr_release,                                 \
3227         .read    = simple_attr_read,                                    \
3228         .write   = simple_attr_write,                                   \
3229         .llseek  = generic_file_llseek,                                 \
3230 }
3231 
3232 static inline __printf(1, 2)
3233 void __simple_attr_check_format(const char *fmt, ...)
3234 {
3235         /* don't do anything, just let the compiler check the arguments; */
3236 }
3237 
3238 int simple_attr_open(struct inode *inode, struct file *file,
3239                      int (*get)(void *, u64 *), int (*set)(void *, u64),
3240                      const char *fmt);
3241 int simple_attr_release(struct inode *inode, struct file *file);
3242 ssize_t simple_attr_read(struct file *file, char __user *buf,
3243                          size_t len, loff_t *ppos);
3244 ssize_t simple_attr_write(struct file *file, const char __user *buf,
3245                           size_t len, loff_t *ppos);
3246 
3247 struct ctl_table;
3248 int proc_nr_files(struct ctl_table *table, int write,
3249                   void __user *buffer, size_t *lenp, loff_t *ppos);
3250 int proc_nr_dentry(struct ctl_table *table, int write,
3251                   void __user *buffer, size_t *lenp, loff_t *ppos);
3252 int proc_nr_inodes(struct ctl_table *table, int write,
3253                    void __user *buffer, size_t *lenp, loff_t *ppos);
3254 int __init get_filesystem_list(char *buf);
3255 
3256 #define __FMODE_EXEC            ((__force int) FMODE_EXEC)
3257 #define __FMODE_NONOTIFY        ((__force int) FMODE_NONOTIFY)
3258 
3259 #define ACC_MODE(x) ("\004\002\006\006"[(x)&O_ACCMODE])
3260 #define OPEN_FMODE(flag) ((__force fmode_t)(((flag + 1) & O_ACCMODE) | \
3261                                             (flag & __FMODE_NONOTIFY)))
3262 
3263 static inline bool is_sxid(umode_t mode)
3264 {
3265         return (mode & S_ISUID) || ((mode & S_ISGID) && (mode & S_IXGRP));
3266 }
3267 
3268 static inline int check_sticky(struct inode *dir, struct inode *inode)
3269 {
3270         if (!(dir->i_mode & S_ISVTX))
3271                 return 0;
3272 
3273         return __check_sticky(dir, inode);
3274 }
3275 
3276 static inline void inode_has_no_xattr(struct inode *inode)
3277 {
3278         if (!is_sxid(inode->i_mode) && (inode->i_sb->s_flags & MS_NOSEC))
3279                 inode->i_flags |= S_NOSEC;
3280 }
3281 
3282 static inline bool is_root_inode(struct inode *inode)
3283 {
3284         return inode == inode->i_sb->s_root->d_inode;
3285 }
3286 
3287 static inline bool dir_emit(struct dir_context *ctx,
3288                             const char *name, int namelen,
3289                             u64 ino, unsigned type)
3290 {
3291         return ctx->actor(ctx, name, namelen, ctx->pos, ino, type) == 0;
3292 }
3293 static inline bool dir_emit_dot(struct file *file, struct dir_context *ctx)
3294 {
3295         return ctx->actor(ctx, ".", 1, ctx->pos,
3296                           file->f_path.dentry->d_inode->i_ino, DT_DIR) == 0;
3297 }
3298 static inline bool dir_emit_dotdot(struct file *file, struct dir_context *ctx)
3299 {
3300         return ctx->actor(ctx, "..", 2, ctx->pos,
3301                           parent_ino(file->f_path.dentry), DT_DIR) == 0;
3302 }
3303 static inline bool dir_emit_dots(struct file *file, struct dir_context *ctx)
3304 {
3305         if (ctx->pos == 0) {
3306                 if (!dir_emit_dot(file, ctx))
3307                         return false;
3308                 ctx->pos = 1;
3309         }
3310         if (ctx->pos == 1) {
3311                 if (!dir_emit_dotdot(file, ctx))
3312                         return false;
3313                 ctx->pos = 2;
3314         }
3315         return true;
3316 }
3317 static inline bool dir_relax(struct inode *inode)
3318 {
3319         inode_unlock(inode);
3320         inode_lock(inode);
3321         return !IS_DEADDIR(inode);
3322 }
3323 
3324 static inline bool dir_relax_shared(struct inode *inode)
3325 {
3326         inode_unlock_shared(inode);
3327         inode_lock_shared(inode);
3328         return !IS_DEADDIR(inode);
3329 }
3330 
3331 extern bool path_noexec(const struct path *path);
3332 extern void inode_nohighmem(struct inode *inode);
3333 
3334 #endif /* _LINUX_FS_H */
3335 

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