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Linux/include/linux/fs.h

  1 #ifndef _LINUX_FS_H
  2 #define _LINUX_FS_H
  3 
  4 #include <linux/linkage.h>
  5 #include <linux/wait.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/capability.h>
 22 #include <linux/semaphore.h>
 23 #include <linux/fiemap.h>
 24 #include <linux/rculist_bl.h>
 25 #include <linux/atomic.h>
 26 #include <linux/shrinker.h>
 27 #include <linux/migrate_mode.h>
 28 #include <linux/uidgid.h>
 29 #include <linux/lockdep.h>
 30 #include <linux/percpu-rwsem.h>
 31 #include <linux/blk_types.h>
 32 #include <linux/workqueue.h>
 33 #include <linux/percpu-rwsem.h>
 34 #include <linux/delayed_call.h>
 35 
 36 #include <asm/byteorder.h>
 37 #include <uapi/linux/fs.h>
 38 
 39 struct backing_dev_info;
 40 struct bdi_writeback;
 41 struct export_operations;
 42 struct hd_geometry;
 43 struct iovec;
 44 struct kiocb;
 45 struct kobject;
 46 struct pipe_inode_info;
 47 struct poll_table_struct;
 48 struct kstatfs;
 49 struct vm_area_struct;
 50 struct vfsmount;
 51 struct cred;
 52 struct swap_info_struct;
 53 struct seq_file;
 54 struct workqueue_struct;
 55 struct iov_iter;
 56 struct fscrypt_info;
 57 struct fscrypt_operations;
 58 
 59 extern void __init inode_init(void);
 60 extern void __init inode_init_early(void);
 61 extern void __init files_init(void);
 62 extern void __init files_maxfiles_init(void);
 63 
 64 extern struct files_stat_struct files_stat;
 65 extern unsigned long get_max_files(void);
 66 extern int sysctl_nr_open;
 67 extern struct inodes_stat_t inodes_stat;
 68 extern int leases_enable, lease_break_time;
 69 extern int sysctl_protected_symlinks;
 70 extern int sysctl_protected_hardlinks;
 71 
 72 struct buffer_head;
 73 typedef int (get_block_t)(struct inode *inode, sector_t iblock,
 74                         struct buffer_head *bh_result, int create);
 75 typedef int (dio_iodone_t)(struct kiocb *iocb, loff_t offset,
 76                         ssize_t bytes, void *private);
 77 
 78 #define MAY_EXEC                0x00000001
 79 #define MAY_WRITE               0x00000002
 80 #define MAY_READ                0x00000004
 81 #define MAY_APPEND              0x00000008
 82 #define MAY_ACCESS              0x00000010
 83 #define MAY_OPEN                0x00000020
 84 #define MAY_CHDIR               0x00000040
 85 /* called from RCU mode, don't block */
 86 #define MAY_NOT_BLOCK           0x00000080
 87 
 88 /*
 89  * flags in file.f_mode.  Note that FMODE_READ and FMODE_WRITE must correspond
 90  * to O_WRONLY and O_RDWR via the strange trick in __dentry_open()
 91  */
 92 
 93 /* file is open for reading */
 94 #define FMODE_READ              ((__force fmode_t)0x1)
 95 /* file is open for writing */
 96 #define FMODE_WRITE             ((__force fmode_t)0x2)
 97 /* file is seekable */
 98 #define FMODE_LSEEK             ((__force fmode_t)0x4)
 99 /* file can be accessed using pread */
100 #define FMODE_PREAD             ((__force fmode_t)0x8)
101 /* file can be accessed using pwrite */
102 #define FMODE_PWRITE            ((__force fmode_t)0x10)
103 /* File is opened for execution with sys_execve / sys_uselib */
104 #define FMODE_EXEC              ((__force fmode_t)0x20)
105 /* File is opened with O_NDELAY (only set for block devices) */
106 #define FMODE_NDELAY            ((__force fmode_t)0x40)
107 /* File is opened with O_EXCL (only set for block devices) */
108 #define FMODE_EXCL              ((__force fmode_t)0x80)
109 /* File is opened using open(.., 3, ..) and is writeable only for ioctls
110    (specialy hack for floppy.c) */
111 #define FMODE_WRITE_IOCTL       ((__force fmode_t)0x100)
112 /* 32bit hashes as llseek() offset (for directories) */
113 #define FMODE_32BITHASH         ((__force fmode_t)0x200)
114 /* 64bit hashes as llseek() offset (for directories) */
115 #define FMODE_64BITHASH         ((__force fmode_t)0x400)
116 
117 /*
118  * Don't update ctime and mtime.
119  *
120  * Currently a special hack for the XFS open_by_handle ioctl, but we'll
121  * hopefully graduate it to a proper O_CMTIME flag supported by open(2) soon.
122  */
123 #define FMODE_NOCMTIME          ((__force fmode_t)0x800)
124 
125 /* Expect random access pattern */
126 #define FMODE_RANDOM            ((__force fmode_t)0x1000)
127 
128 /* File is huge (eg. /dev/kmem): treat loff_t as unsigned */
129 #define FMODE_UNSIGNED_OFFSET   ((__force fmode_t)0x2000)
130 
131 /* File is opened with O_PATH; almost nothing can be done with it */
132 #define FMODE_PATH              ((__force fmode_t)0x4000)
133 
134 /* File needs atomic accesses to f_pos */
135 #define FMODE_ATOMIC_POS        ((__force fmode_t)0x8000)
136 /* Write access to underlying fs */
137 #define FMODE_WRITER            ((__force fmode_t)0x10000)
138 /* Has read method(s) */
139 #define FMODE_CAN_READ          ((__force fmode_t)0x20000)
140 /* Has write method(s) */
141 #define FMODE_CAN_WRITE         ((__force fmode_t)0x40000)
142 
143 /* File was opened by fanotify and shouldn't generate fanotify events */
144 #define FMODE_NONOTIFY          ((__force fmode_t)0x4000000)
145 
146 /*
147  * Flag for rw_copy_check_uvector and compat_rw_copy_check_uvector
148  * that indicates that they should check the contents of the iovec are
149  * valid, but not check the memory that the iovec elements
150  * points too.
151  */
152 #define CHECK_IOVEC_ONLY -1
153 
154 /*
155  * The below are the various read and write types that we support. Some of
156  * them include behavioral modifiers that send information down to the
157  * block layer and IO scheduler. Terminology:
158  *
159  *      The block layer uses device plugging to defer IO a little bit, in
160  *      the hope that we will see more IO very shortly. This increases
161  *      coalescing of adjacent IO and thus reduces the number of IOs we
162  *      have to send to the device. It also allows for better queuing,
163  *      if the IO isn't mergeable. If the caller is going to be waiting
164  *      for the IO, then he must ensure that the device is unplugged so
165  *      that the IO is dispatched to the driver.
166  *
167  *      All IO is handled async in Linux. This is fine for background
168  *      writes, but for reads or writes that someone waits for completion
169  *      on, we want to notify the block layer and IO scheduler so that they
170  *      know about it. That allows them to make better scheduling
171  *      decisions. So when the below references 'sync' and 'async', it
172  *      is referencing this priority hint.
173  *
174  * With that in mind, the available types are:
175  *
176  * READ                 A normal read operation. Device will be plugged.
177  * READ_SYNC            A synchronous read. Device is not plugged, caller can
178  *                      immediately wait on this read without caring about
179  *                      unplugging.
180  * READA                Used for read-ahead operations. Lower priority, and the
181  *                      block layer could (in theory) choose to ignore this
182  *                      request if it runs into resource problems.
183  * WRITE                A normal async write. Device will be plugged.
184  * WRITE_SYNC           Synchronous write. Identical to WRITE, but passes down
185  *                      the hint that someone will be waiting on this IO
186  *                      shortly. The write equivalent of READ_SYNC.
187  * WRITE_ODIRECT        Special case write for O_DIRECT only.
188  * WRITE_FLUSH          Like WRITE_SYNC but with preceding cache flush.
189  * WRITE_FUA            Like WRITE_SYNC but data is guaranteed to be on
190  *                      non-volatile media on completion.
191  * WRITE_FLUSH_FUA      Combination of WRITE_FLUSH and FUA. The IO is preceded
192  *                      by a cache flush and data is guaranteed to be on
193  *                      non-volatile media on completion.
194  *
195  */
196 #define RW_MASK                 REQ_WRITE
197 #define RWA_MASK                REQ_RAHEAD
198 
199 #define READ                    0
200 #define WRITE                   RW_MASK
201 #define READA                   RWA_MASK
202 
203 #define READ_SYNC               (READ | REQ_SYNC)
204 #define WRITE_SYNC              (WRITE | REQ_SYNC | REQ_NOIDLE)
205 #define WRITE_ODIRECT           (WRITE | REQ_SYNC)
206 #define WRITE_FLUSH             (WRITE | REQ_SYNC | REQ_NOIDLE | REQ_FLUSH)
207 #define WRITE_FUA               (WRITE | REQ_SYNC | REQ_NOIDLE | REQ_FUA)
208 #define WRITE_FLUSH_FUA         (WRITE | REQ_SYNC | REQ_NOIDLE | REQ_FLUSH | REQ_FUA)
209 
210 /*
211  * Attribute flags.  These should be or-ed together to figure out what
212  * has been changed!
213  */
214 #define ATTR_MODE       (1 << 0)
215 #define ATTR_UID        (1 << 1)
216 #define ATTR_GID        (1 << 2)
217 #define ATTR_SIZE       (1 << 3)
218 #define ATTR_ATIME      (1 << 4)
219 #define ATTR_MTIME      (1 << 5)
220 #define ATTR_CTIME      (1 << 6)
221 #define ATTR_ATIME_SET  (1 << 7)
222 #define ATTR_MTIME_SET  (1 << 8)
223 #define ATTR_FORCE      (1 << 9) /* Not a change, but a change it */
224 #define ATTR_ATTR_FLAG  (1 << 10)
225 #define ATTR_KILL_SUID  (1 << 11)
226 #define ATTR_KILL_SGID  (1 << 12)
227 #define ATTR_FILE       (1 << 13)
228 #define ATTR_KILL_PRIV  (1 << 14)
229 #define ATTR_OPEN       (1 << 15) /* Truncating from open(O_TRUNC) */
230 #define ATTR_TIMES_SET  (1 << 16)
231 
232 /*
233  * Whiteout is represented by a char device.  The following constants define the
234  * mode and device number to use.
235  */
236 #define WHITEOUT_MODE 0
237 #define WHITEOUT_DEV 0
238 
239 /*
240  * This is the Inode Attributes structure, used for notify_change().  It
241  * uses the above definitions as flags, to know which values have changed.
242  * Also, in this manner, a Filesystem can look at only the values it cares
243  * about.  Basically, these are the attributes that the VFS layer can
244  * request to change from the FS layer.
245  *
246  * Derek Atkins <warlord@MIT.EDU> 94-10-20
247  */
248 struct iattr {
249         unsigned int    ia_valid;
250         umode_t         ia_mode;
251         kuid_t          ia_uid;
252         kgid_t          ia_gid;
253         loff_t          ia_size;
254         struct timespec ia_atime;
255         struct timespec ia_mtime;
256         struct timespec ia_ctime;
257 
258         /*
259          * Not an attribute, but an auxiliary info for filesystems wanting to
260          * implement an ftruncate() like method.  NOTE: filesystem should
261          * check for (ia_valid & ATTR_FILE), and not for (ia_file != NULL).
262          */
263         struct file     *ia_file;
264 };
265 
266 /*
267  * Includes for diskquotas.
268  */
269 #include <linux/quota.h>
270 
271 /*
272  * Maximum number of layers of fs stack.  Needs to be limited to
273  * prevent kernel stack overflow
274  */
275 #define FILESYSTEM_MAX_STACK_DEPTH 2
276 
277 /** 
278  * enum positive_aop_returns - aop return codes with specific semantics
279  *
280  * @AOP_WRITEPAGE_ACTIVATE: Informs the caller that page writeback has
281  *                          completed, that the page is still locked, and
282  *                          should be considered active.  The VM uses this hint
283  *                          to return the page to the active list -- it won't
284  *                          be a candidate for writeback again in the near
285  *                          future.  Other callers must be careful to unlock
286  *                          the page if they get this return.  Returned by
287  *                          writepage(); 
288  *
289  * @AOP_TRUNCATED_PAGE: The AOP method that was handed a locked page has
290  *                      unlocked it and the page might have been truncated.
291  *                      The caller should back up to acquiring a new page and
292  *                      trying again.  The aop will be taking reasonable
293  *                      precautions not to livelock.  If the caller held a page
294  *                      reference, it should drop it before retrying.  Returned
295  *                      by readpage().
296  *
297  * address_space_operation functions return these large constants to indicate
298  * special semantics to the caller.  These are much larger than the bytes in a
299  * page to allow for functions that return the number of bytes operated on in a
300  * given page.
301  */
302 
303 enum positive_aop_returns {
304         AOP_WRITEPAGE_ACTIVATE  = 0x80000,
305         AOP_TRUNCATED_PAGE      = 0x80001,
306 };
307 
308 #define AOP_FLAG_UNINTERRUPTIBLE        0x0001 /* will not do a short write */
309 #define AOP_FLAG_CONT_EXPAND            0x0002 /* called from cont_expand */
310 #define AOP_FLAG_NOFS                   0x0004 /* used by filesystem to direct
311                                                 * helper code (eg buffer layer)
312                                                 * to clear GFP_FS from alloc */
313 
314 /*
315  * oh the beauties of C type declarations.
316  */
317 struct page;
318 struct address_space;
319 struct writeback_control;
320 
321 #define IOCB_EVENTFD            (1 << 0)
322 #define IOCB_APPEND             (1 << 1)
323 #define IOCB_DIRECT             (1 << 2)
324 #define IOCB_HIPRI              (1 << 3)
325 #define IOCB_DSYNC              (1 << 4)
326 #define IOCB_SYNC               (1 << 5)
327 
328 struct kiocb {
329         struct file             *ki_filp;
330         loff_t                  ki_pos;
331         void (*ki_complete)(struct kiocb *iocb, long ret, long ret2);
332         void                    *private;
333         int                     ki_flags;
334 };
335 
336 static inline bool is_sync_kiocb(struct kiocb *kiocb)
337 {
338         return kiocb->ki_complete == NULL;
339 }
340 
341 static inline int iocb_flags(struct file *file);
342 
343 static inline void init_sync_kiocb(struct kiocb *kiocb, struct file *filp)
344 {
345         *kiocb = (struct kiocb) {
346                 .ki_filp = filp,
347                 .ki_flags = iocb_flags(filp),
348         };
349 }
350 
351 /*
352  * "descriptor" for what we're up to with a read.
353  * This allows us to use the same read code yet
354  * have multiple different users of the data that
355  * we read from a file.
356  *
357  * The simplest case just copies the data to user
358  * mode.
359  */
360 typedef struct {
361         size_t written;
362         size_t count;
363         union {
364                 char __user *buf;
365                 void *data;
366         } arg;
367         int error;
368 } read_descriptor_t;
369 
370 typedef int (*read_actor_t)(read_descriptor_t *, struct page *,
371                 unsigned long, unsigned long);
372 
373 struct address_space_operations {
374         int (*writepage)(struct page *page, struct writeback_control *wbc);
375         int (*readpage)(struct file *, struct page *);
376 
377         /* Write back some dirty pages from this mapping. */
378         int (*writepages)(struct address_space *, struct writeback_control *);
379 
380         /* Set a page dirty.  Return true if this dirtied it */
381         int (*set_page_dirty)(struct page *page);
382 
383         int (*readpages)(struct file *filp, struct address_space *mapping,
384                         struct list_head *pages, unsigned nr_pages);
385 
386         int (*write_begin)(struct file *, struct address_space *mapping,
387                                 loff_t pos, unsigned len, unsigned flags,
388                                 struct page **pagep, void **fsdata);
389         int (*write_end)(struct file *, struct address_space *mapping,
390                                 loff_t pos, unsigned len, unsigned copied,
391                                 struct page *page, void *fsdata);
392 
393         /* Unfortunately this kludge is needed for FIBMAP. Don't use it */
394         sector_t (*bmap)(struct address_space *, sector_t);
395         void (*invalidatepage) (struct page *, unsigned int, unsigned int);
396         int (*releasepage) (struct page *, gfp_t);
397         void (*freepage)(struct page *);
398         ssize_t (*direct_IO)(struct kiocb *, struct iov_iter *iter);
399         /*
400          * migrate the contents of a page to the specified target. If
401          * migrate_mode is MIGRATE_ASYNC, it must not block.
402          */
403         int (*migratepage) (struct address_space *,
404                         struct page *, struct page *, enum migrate_mode);
405         int (*launder_page) (struct page *);
406         int (*is_partially_uptodate) (struct page *, unsigned long,
407                                         unsigned long);
408         void (*is_dirty_writeback) (struct page *, bool *, bool *);
409         int (*error_remove_page)(struct address_space *, struct page *);
410 
411         /* swapfile support */
412         int (*swap_activate)(struct swap_info_struct *sis, struct file *file,
413                                 sector_t *span);
414         void (*swap_deactivate)(struct file *file);
415 };
416 
417 extern const struct address_space_operations empty_aops;
418 
419 /*
420  * pagecache_write_begin/pagecache_write_end must be used by general code
421  * to write into the pagecache.
422  */
423 int pagecache_write_begin(struct file *, struct address_space *mapping,
424                                 loff_t pos, unsigned len, unsigned flags,
425                                 struct page **pagep, void **fsdata);
426 
427 int pagecache_write_end(struct file *, struct address_space *mapping,
428                                 loff_t pos, unsigned len, unsigned copied,
429                                 struct page *page, void *fsdata);
430 
431 struct address_space {
432         struct inode            *host;          /* owner: inode, block_device */
433         struct radix_tree_root  page_tree;      /* radix tree of all pages */
434         spinlock_t              tree_lock;      /* and lock protecting it */
435         atomic_t                i_mmap_writable;/* count VM_SHARED mappings */
436         struct rb_root          i_mmap;         /* tree of private and shared mappings */
437         struct rw_semaphore     i_mmap_rwsem;   /* protect tree, count, list */
438         /* Protected by tree_lock together with the radix tree */
439         unsigned long           nrpages;        /* number of total pages */
440         /* number of shadow or DAX exceptional entries */
441         unsigned long           nrexceptional;
442         pgoff_t                 writeback_index;/* writeback starts here */
443         const struct address_space_operations *a_ops;   /* methods */
444         unsigned long           flags;          /* error bits/gfp mask */
445         spinlock_t              private_lock;   /* for use by the address_space */
446         struct list_head        private_list;   /* ditto */
447         void                    *private_data;  /* ditto */
448 } __attribute__((aligned(sizeof(long))));
449         /*
450          * On most architectures that alignment is already the case; but
451          * must be enforced here for CRIS, to let the least significant bit
452          * of struct page's "mapping" pointer be used for PAGE_MAPPING_ANON.
453          */
454 struct request_queue;
455 
456 struct block_device {
457         dev_t                   bd_dev;  /* not a kdev_t - it's a search key */
458         int                     bd_openers;
459         struct inode *          bd_inode;       /* will die */
460         struct super_block *    bd_super;
461         struct mutex            bd_mutex;       /* open/close mutex */
462         struct list_head        bd_inodes;
463         void *                  bd_claiming;
464         void *                  bd_holder;
465         int                     bd_holders;
466         bool                    bd_write_holder;
467 #ifdef CONFIG_SYSFS
468         struct list_head        bd_holder_disks;
469 #endif
470         struct block_device *   bd_contains;
471         unsigned                bd_block_size;
472         struct hd_struct *      bd_part;
473         /* number of times partitions within this device have been opened. */
474         unsigned                bd_part_count;
475         int                     bd_invalidated;
476         struct gendisk *        bd_disk;
477         struct request_queue *  bd_queue;
478         struct list_head        bd_list;
479         /*
480          * Private data.  You must have bd_claim'ed the block_device
481          * to use this.  NOTE:  bd_claim allows an owner to claim
482          * the same device multiple times, the owner must take special
483          * care to not mess up bd_private for that case.
484          */
485         unsigned long           bd_private;
486 
487         /* The counter of freeze processes */
488         int                     bd_fsfreeze_count;
489         /* Mutex for freeze */
490         struct mutex            bd_fsfreeze_mutex;
491 };
492 
493 /*
494  * Radix-tree tags, for tagging dirty and writeback pages within the pagecache
495  * radix trees
496  */
497 #define PAGECACHE_TAG_DIRTY     0
498 #define PAGECACHE_TAG_WRITEBACK 1
499 #define PAGECACHE_TAG_TOWRITE   2
500 
501 int mapping_tagged(struct address_space *mapping, int tag);
502 
503 static inline void i_mmap_lock_write(struct address_space *mapping)
504 {
505         down_write(&mapping->i_mmap_rwsem);
506 }
507 
508 static inline void i_mmap_unlock_write(struct address_space *mapping)
509 {
510         up_write(&mapping->i_mmap_rwsem);
511 }
512 
513 static inline void i_mmap_lock_read(struct address_space *mapping)
514 {
515         down_read(&mapping->i_mmap_rwsem);
516 }
517 
518 static inline void i_mmap_unlock_read(struct address_space *mapping)
519 {
520         up_read(&mapping->i_mmap_rwsem);
521 }
522 
523 /*
524  * Might pages of this file be mapped into userspace?
525  */
526 static inline int mapping_mapped(struct address_space *mapping)
527 {
528         return  !RB_EMPTY_ROOT(&mapping->i_mmap);
529 }
530 
531 /*
532  * Might pages of this file have been modified in userspace?
533  * Note that i_mmap_writable counts all VM_SHARED vmas: do_mmap_pgoff
534  * marks vma as VM_SHARED if it is shared, and the file was opened for
535  * writing i.e. vma may be mprotected writable even if now readonly.
536  *
537  * If i_mmap_writable is negative, no new writable mappings are allowed. You
538  * can only deny writable mappings, if none exists right now.
539  */
540 static inline int mapping_writably_mapped(struct address_space *mapping)
541 {
542         return atomic_read(&mapping->i_mmap_writable) > 0;
543 }
544 
545 static inline int mapping_map_writable(struct address_space *mapping)
546 {
547         return atomic_inc_unless_negative(&mapping->i_mmap_writable) ?
548                 0 : -EPERM;
549 }
550 
551 static inline void mapping_unmap_writable(struct address_space *mapping)
552 {
553         atomic_dec(&mapping->i_mmap_writable);
554 }
555 
556 static inline int mapping_deny_writable(struct address_space *mapping)
557 {
558         return atomic_dec_unless_positive(&mapping->i_mmap_writable) ?
559                 0 : -EBUSY;
560 }
561 
562 static inline void mapping_allow_writable(struct address_space *mapping)
563 {
564         atomic_inc(&mapping->i_mmap_writable);
565 }
566 
567 /*
568  * Use sequence counter to get consistent i_size on 32-bit processors.
569  */
570 #if BITS_PER_LONG==32 && defined(CONFIG_SMP)
571 #include <linux/seqlock.h>
572 #define __NEED_I_SIZE_ORDERED
573 #define i_size_ordered_init(inode) seqcount_init(&inode->i_size_seqcount)
574 #else
575 #define i_size_ordered_init(inode) do { } while (0)
576 #endif
577 
578 struct posix_acl;
579 #define ACL_NOT_CACHED ((void *)(-1))
580 
581 static inline struct posix_acl *
582 uncached_acl_sentinel(struct task_struct *task)
583 {
584         return (void *)task + 1;
585 }
586 
587 static inline bool
588 is_uncached_acl(struct posix_acl *acl)
589 {
590         return (long)acl & 1;
591 }
592 
593 #define IOP_FASTPERM    0x0001
594 #define IOP_LOOKUP      0x0002
595 #define IOP_NOFOLLOW    0x0004
596 
597 /*
598  * Keep mostly read-only and often accessed (especially for
599  * the RCU path lookup and 'stat' data) fields at the beginning
600  * of the 'struct inode'
601  */
602 struct inode {
603         umode_t                 i_mode;
604         unsigned short          i_opflags;
605         kuid_t                  i_uid;
606         kgid_t                  i_gid;
607         unsigned int            i_flags;
608 
609 #ifdef CONFIG_FS_POSIX_ACL
610         struct posix_acl        *i_acl;
611         struct posix_acl        *i_default_acl;
612 #endif
613 
614         const struct inode_operations   *i_op;
615         struct super_block      *i_sb;
616         struct address_space    *i_mapping;
617 
618 #ifdef CONFIG_SECURITY
619         void                    *i_security;
620 #endif
621 
622         /* Stat data, not accessed from path walking */
623         unsigned long           i_ino;
624         /*
625          * Filesystems may only read i_nlink directly.  They shall use the
626          * following functions for modification:
627          *
628          *    (set|clear|inc|drop)_nlink
629          *    inode_(inc|dec)_link_count
630          */
631         union {
632                 const unsigned int i_nlink;
633                 unsigned int __i_nlink;
634         };
635         dev_t                   i_rdev;
636         loff_t                  i_size;
637         struct timespec         i_atime;
638         struct timespec         i_mtime;
639         struct timespec         i_ctime;
640         spinlock_t              i_lock; /* i_blocks, i_bytes, maybe i_size */
641         unsigned short          i_bytes;
642         unsigned int            i_blkbits;
643         blkcnt_t                i_blocks;
644 
645 #ifdef __NEED_I_SIZE_ORDERED
646         seqcount_t              i_size_seqcount;
647 #endif
648 
649         /* Misc */
650         unsigned long           i_state;
651         struct rw_semaphore     i_rwsem;
652 
653         unsigned long           dirtied_when;   /* jiffies of first dirtying */
654         unsigned long           dirtied_time_when;
655 
656         struct hlist_node       i_hash;
657         struct list_head        i_io_list;      /* backing dev IO list */
658 #ifdef CONFIG_CGROUP_WRITEBACK
659         struct bdi_writeback    *i_wb;          /* the associated cgroup wb */
660 
661         /* foreign inode detection, see wbc_detach_inode() */
662         int                     i_wb_frn_winner;
663         u16                     i_wb_frn_avg_time;
664         u16                     i_wb_frn_history;
665 #endif
666         struct list_head        i_lru;          /* inode LRU list */
667         struct list_head        i_sb_list;
668         union {
669                 struct hlist_head       i_dentry;
670                 struct rcu_head         i_rcu;
671         };
672         u64                     i_version;
673         atomic_t                i_count;
674         atomic_t                i_dio_count;
675         atomic_t                i_writecount;
676 #ifdef CONFIG_IMA
677         atomic_t                i_readcount; /* struct files open RO */
678 #endif
679         const struct file_operations    *i_fop; /* former ->i_op->default_file_ops */
680         struct file_lock_context        *i_flctx;
681         struct address_space    i_data;
682         struct list_head        i_devices;
683         union {
684                 struct pipe_inode_info  *i_pipe;
685                 struct block_device     *i_bdev;
686                 struct cdev             *i_cdev;
687                 char                    *i_link;
688                 unsigned                i_dir_seq;
689         };
690 
691         __u32                   i_generation;
692 
693 #ifdef CONFIG_FSNOTIFY
694         __u32                   i_fsnotify_mask; /* all events this inode cares about */
695         struct hlist_head       i_fsnotify_marks;
696 #endif
697 
698 #if IS_ENABLED(CONFIG_FS_ENCRYPTION)
699         struct fscrypt_info     *i_crypt_info;
700 #endif
701 
702         void                    *i_private; /* fs or device private pointer */
703 };
704 
705 static inline int inode_unhashed(struct inode *inode)
706 {
707         return hlist_unhashed(&inode->i_hash);
708 }
709 
710 /*
711  * inode->i_mutex nesting subclasses for the lock validator:
712  *
713  * 0: the object of the current VFS operation
714  * 1: parent
715  * 2: child/target
716  * 3: xattr
717  * 4: second non-directory
718  * 5: second parent (when locking independent directories in rename)
719  *
720  * I_MUTEX_NONDIR2 is for certain operations (such as rename) which lock two
721  * non-directories at once.
722  *
723  * The locking order between these classes is
724  * parent[2] -> child -> grandchild -> normal -> xattr -> second non-directory
725  */
726 enum inode_i_mutex_lock_class
727 {
728         I_MUTEX_NORMAL,
729         I_MUTEX_PARENT,
730         I_MUTEX_CHILD,
731         I_MUTEX_XATTR,
732         I_MUTEX_NONDIR2,
733         I_MUTEX_PARENT2,
734 };
735 
736 static inline void inode_lock(struct inode *inode)
737 {
738         down_write(&inode->i_rwsem);
739 }
740 
741 static inline void inode_unlock(struct inode *inode)
742 {
743         up_write(&inode->i_rwsem);
744 }
745 
746 static inline void inode_lock_shared(struct inode *inode)
747 {
748         down_read(&inode->i_rwsem);
749 }
750 
751 static inline void inode_unlock_shared(struct inode *inode)
752 {
753         up_read(&inode->i_rwsem);
754 }
755 
756 static inline int inode_trylock(struct inode *inode)
757 {
758         return down_write_trylock(&inode->i_rwsem);
759 }
760 
761 static inline int inode_trylock_shared(struct inode *inode)
762 {
763         return down_read_trylock(&inode->i_rwsem);
764 }
765 
766 static inline int inode_is_locked(struct inode *inode)
767 {
768         return rwsem_is_locked(&inode->i_rwsem);
769 }
770 
771 static inline void inode_lock_nested(struct inode *inode, unsigned subclass)
772 {
773         down_write_nested(&inode->i_rwsem, subclass);
774 }
775 
776 void lock_two_nondirectories(struct inode *, struct inode*);
777 void unlock_two_nondirectories(struct inode *, struct inode*);
778 
779 /*
780  * NOTE: in a 32bit arch with a preemptable kernel and
781  * an UP compile the i_size_read/write must be atomic
782  * with respect to the local cpu (unlike with preempt disabled),
783  * but they don't need to be atomic with respect to other cpus like in
784  * true SMP (so they need either to either locally disable irq around
785  * the read or for example on x86 they can be still implemented as a
786  * cmpxchg8b without the need of the lock prefix). For SMP compiles
787  * and 64bit archs it makes no difference if preempt is enabled or not.
788  */
789 static inline loff_t i_size_read(const struct inode *inode)
790 {
791 #if BITS_PER_LONG==32 && defined(CONFIG_SMP)
792         loff_t i_size;
793         unsigned int seq;
794 
795         do {
796                 seq = read_seqcount_begin(&inode->i_size_seqcount);
797                 i_size = inode->i_size;
798         } while (read_seqcount_retry(&inode->i_size_seqcount, seq));
799         return i_size;
800 #elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPT)
801         loff_t i_size;
802 
803         preempt_disable();
804         i_size = inode->i_size;
805         preempt_enable();
806         return i_size;
807 #else
808         return inode->i_size;
809 #endif
810 }
811 
812 /*
813  * NOTE: unlike i_size_read(), i_size_write() does need locking around it
814  * (normally i_mutex), otherwise on 32bit/SMP an update of i_size_seqcount
815  * can be lost, resulting in subsequent i_size_read() calls spinning forever.
816  */
817 static inline void i_size_write(struct inode *inode, loff_t i_size)
818 {
819 #if BITS_PER_LONG==32 && defined(CONFIG_SMP)
820         preempt_disable();
821         write_seqcount_begin(&inode->i_size_seqcount);
822         inode->i_size = i_size;
823         write_seqcount_end(&inode->i_size_seqcount);
824         preempt_enable();
825 #elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPT)
826         preempt_disable();
827         inode->i_size = i_size;
828         preempt_enable();
829 #else
830         inode->i_size = i_size;
831 #endif
832 }
833 
834 /* Helper functions so that in most cases filesystems will
835  * not need to deal directly with kuid_t and kgid_t and can
836  * instead deal with the raw numeric values that are stored
837  * in the filesystem.
838  */
839 static inline uid_t i_uid_read(const struct inode *inode)
840 {
841         return from_kuid(&init_user_ns, inode->i_uid);
842 }
843 
844 static inline gid_t i_gid_read(const struct inode *inode)
845 {
846         return from_kgid(&init_user_ns, inode->i_gid);
847 }
848 
849 static inline void i_uid_write(struct inode *inode, uid_t uid)
850 {
851         inode->i_uid = make_kuid(&init_user_ns, uid);
852 }
853 
854 static inline void i_gid_write(struct inode *inode, gid_t gid)
855 {
856         inode->i_gid = make_kgid(&init_user_ns, gid);
857 }
858 
859 static inline unsigned iminor(const struct inode *inode)
860 {
861         return MINOR(inode->i_rdev);
862 }
863 
864 static inline unsigned imajor(const struct inode *inode)
865 {
866         return MAJOR(inode->i_rdev);
867 }
868 
869 extern struct block_device *I_BDEV(struct inode *inode);
870 
871 struct fown_struct {
872         rwlock_t lock;          /* protects pid, uid, euid fields */
873         struct pid *pid;        /* pid or -pgrp where SIGIO should be sent */
874         enum pid_type pid_type; /* Kind of process group SIGIO should be sent to */
875         kuid_t uid, euid;       /* uid/euid of process setting the owner */
876         int signum;             /* posix.1b rt signal to be delivered on IO */
877 };
878 
879 /*
880  * Track a single file's readahead state
881  */
882 struct file_ra_state {
883         pgoff_t start;                  /* where readahead started */
884         unsigned int size;              /* # of readahead pages */
885         unsigned int async_size;        /* do asynchronous readahead when
886                                            there are only # of pages ahead */
887 
888         unsigned int ra_pages;          /* Maximum readahead window */
889         unsigned int mmap_miss;         /* Cache miss stat for mmap accesses */
890         loff_t prev_pos;                /* Cache last read() position */
891 };
892 
893 /*
894  * Check if @index falls in the readahead windows.
895  */
896 static inline int ra_has_index(struct file_ra_state *ra, pgoff_t index)
897 {
898         return (index >= ra->start &&
899                 index <  ra->start + ra->size);
900 }
901 
902 struct file {
903         union {
904                 struct llist_node       fu_llist;
905                 struct rcu_head         fu_rcuhead;
906         } f_u;
907         struct path             f_path;
908         struct inode            *f_inode;       /* cached value */
909         const struct file_operations    *f_op;
910 
911         /*
912          * Protects f_ep_links, f_flags.
913          * Must not be taken from IRQ context.
914          */
915         spinlock_t              f_lock;
916         atomic_long_t           f_count;
917         unsigned int            f_flags;
918         fmode_t                 f_mode;
919         struct mutex            f_pos_lock;
920         loff_t                  f_pos;
921         struct fown_struct      f_owner;
922         const struct cred       *f_cred;
923         struct file_ra_state    f_ra;
924 
925         u64                     f_version;
926 #ifdef CONFIG_SECURITY
927         void                    *f_security;
928 #endif
929         /* needed for tty driver, and maybe others */
930         void                    *private_data;
931 
932 #ifdef CONFIG_EPOLL
933         /* Used by fs/eventpoll.c to link all the hooks to this file */
934         struct list_head        f_ep_links;
935         struct list_head        f_tfile_llink;
936 #endif /* #ifdef CONFIG_EPOLL */
937         struct address_space    *f_mapping;
938 } __attribute__((aligned(4)));  /* lest something weird decides that 2 is OK */
939 
940 struct file_handle {
941         __u32 handle_bytes;
942         int handle_type;
943         /* file identifier */
944         unsigned char f_handle[0];
945 };
946 
947 static inline struct file *get_file(struct file *f)
948 {
949         atomic_long_inc(&f->f_count);
950         return f;
951 }
952 #define get_file_rcu(x) atomic_long_inc_not_zero(&(x)->f_count)
953 #define fput_atomic(x)  atomic_long_add_unless(&(x)->f_count, -1, 1)
954 #define file_count(x)   atomic_long_read(&(x)->f_count)
955 
956 #define MAX_NON_LFS     ((1UL<<31) - 1)
957 
958 /* Page cache limit. The filesystems should put that into their s_maxbytes 
959    limits, otherwise bad things can happen in VM. */ 
960 #if BITS_PER_LONG==32
961 #define MAX_LFS_FILESIZE        (((loff_t)PAGE_SIZE << (BITS_PER_LONG-1))-1)
962 #elif BITS_PER_LONG==64
963 #define MAX_LFS_FILESIZE        ((loff_t)0x7fffffffffffffffLL)
964 #endif
965 
966 #define FL_POSIX        1
967 #define FL_FLOCK        2
968 #define FL_DELEG        4       /* NFSv4 delegation */
969 #define FL_ACCESS       8       /* not trying to lock, just looking */
970 #define FL_EXISTS       16      /* when unlocking, test for existence */
971 #define FL_LEASE        32      /* lease held on this file */
972 #define FL_CLOSE        64      /* unlock on close */
973 #define FL_SLEEP        128     /* A blocking lock */
974 #define FL_DOWNGRADE_PENDING    256 /* Lease is being downgraded */
975 #define FL_UNLOCK_PENDING       512 /* Lease is being broken */
976 #define FL_OFDLCK       1024    /* lock is "owned" by struct file */
977 #define FL_LAYOUT       2048    /* outstanding pNFS layout */
978 
979 /*
980  * Special return value from posix_lock_file() and vfs_lock_file() for
981  * asynchronous locking.
982  */
983 #define FILE_LOCK_DEFERRED 1
984 
985 /* legacy typedef, should eventually be removed */
986 typedef void *fl_owner_t;
987 
988 struct file_lock;
989 
990 struct file_lock_operations {
991         void (*fl_copy_lock)(struct file_lock *, struct file_lock *);
992         void (*fl_release_private)(struct file_lock *);
993 };
994 
995 struct lock_manager_operations {
996         int (*lm_compare_owner)(struct file_lock *, struct file_lock *);
997         unsigned long (*lm_owner_key)(struct file_lock *);
998         fl_owner_t (*lm_get_owner)(fl_owner_t);
999         void (*lm_put_owner)(fl_owner_t);
1000         void (*lm_notify)(struct file_lock *);  /* unblock callback */
1001         int (*lm_grant)(struct file_lock *, int);
1002         bool (*lm_break)(struct file_lock *);
1003         int (*lm_change)(struct file_lock *, int, struct list_head *);
1004         void (*lm_setup)(struct file_lock *, void **);
1005 };
1006 
1007 struct lock_manager {
1008         struct list_head list;
1009         /*
1010          * NFSv4 and up also want opens blocked during the grace period;
1011          * NLM doesn't care:
1012          */
1013         bool block_opens;
1014 };
1015 
1016 struct net;
1017 void locks_start_grace(struct net *, struct lock_manager *);
1018 void locks_end_grace(struct lock_manager *);
1019 int locks_in_grace(struct net *);
1020 int opens_in_grace(struct net *);
1021 
1022 /* that will die - we need it for nfs_lock_info */
1023 #include <linux/nfs_fs_i.h>
1024 
1025 /*
1026  * struct file_lock represents a generic "file lock". It's used to represent
1027  * POSIX byte range locks, BSD (flock) locks, and leases. It's important to
1028  * note that the same struct is used to represent both a request for a lock and
1029  * the lock itself, but the same object is never used for both.
1030  *
1031  * FIXME: should we create a separate "struct lock_request" to help distinguish
1032  * these two uses?
1033  *
1034  * The varous i_flctx lists are ordered by:
1035  *
1036  * 1) lock owner
1037  * 2) lock range start
1038  * 3) lock range end
1039  *
1040  * Obviously, the last two criteria only matter for POSIX locks.
1041  */
1042 struct file_lock {
1043         struct file_lock *fl_next;      /* singly linked list for this inode  */
1044         struct list_head fl_list;       /* link into file_lock_context */
1045         struct hlist_node fl_link;      /* node in global lists */
1046         struct list_head fl_block;      /* circular list of blocked processes */
1047         fl_owner_t fl_owner;
1048         unsigned int fl_flags;
1049         unsigned char fl_type;
1050         unsigned int fl_pid;
1051         int fl_link_cpu;                /* what cpu's list is this on? */
1052         struct pid *fl_nspid;
1053         wait_queue_head_t fl_wait;
1054         struct file *fl_file;
1055         loff_t fl_start;
1056         loff_t fl_end;
1057 
1058         struct fasync_struct *  fl_fasync; /* for lease break notifications */
1059         /* for lease breaks: */
1060         unsigned long fl_break_time;
1061         unsigned long fl_downgrade_time;
1062 
1063         const struct file_lock_operations *fl_ops;      /* Callbacks for filesystems */
1064         const struct lock_manager_operations *fl_lmops; /* Callbacks for lockmanagers */
1065         union {
1066                 struct nfs_lock_info    nfs_fl;
1067                 struct nfs4_lock_info   nfs4_fl;
1068                 struct {
1069                         struct list_head link;  /* link in AFS vnode's pending_locks list */
1070                         int state;              /* state of grant or error if -ve */
1071                 } afs;
1072         } fl_u;
1073 };
1074 
1075 struct file_lock_context {
1076         spinlock_t              flc_lock;
1077         struct list_head        flc_flock;
1078         struct list_head        flc_posix;
1079         struct list_head        flc_lease;
1080 };
1081 
1082 /* The following constant reflects the upper bound of the file/locking space */
1083 #ifndef OFFSET_MAX
1084 #define INT_LIMIT(x)    (~((x)1 << (sizeof(x)*8 - 1)))
1085 #define OFFSET_MAX      INT_LIMIT(loff_t)
1086 #define OFFT_OFFSET_MAX INT_LIMIT(off_t)
1087 #endif
1088 
1089 #include <linux/fcntl.h>
1090 
1091 extern void send_sigio(struct fown_struct *fown, int fd, int band);
1092 
1093 #ifdef CONFIG_FILE_LOCKING
1094 extern int fcntl_getlk(struct file *, unsigned int, struct flock __user *);
1095 extern int fcntl_setlk(unsigned int, struct file *, unsigned int,
1096                         struct flock __user *);
1097 
1098 #if BITS_PER_LONG == 32
1099 extern int fcntl_getlk64(struct file *, unsigned int, struct flock64 __user *);
1100 extern int fcntl_setlk64(unsigned int, struct file *, unsigned int,
1101                         struct flock64 __user *);
1102 #endif
1103 
1104 extern int fcntl_setlease(unsigned int fd, struct file *filp, long arg);
1105 extern int fcntl_getlease(struct file *filp);
1106 
1107 /* fs/locks.c */
1108 void locks_free_lock_context(struct inode *inode);
1109 void locks_free_lock(struct file_lock *fl);
1110 extern void locks_init_lock(struct file_lock *);
1111 extern struct file_lock * locks_alloc_lock(void);
1112 extern void locks_copy_lock(struct file_lock *, struct file_lock *);
1113 extern void locks_copy_conflock(struct file_lock *, struct file_lock *);
1114 extern void locks_remove_posix(struct file *, fl_owner_t);
1115 extern void locks_remove_file(struct file *);
1116 extern void locks_release_private(struct file_lock *);
1117 extern void posix_test_lock(struct file *, struct file_lock *);
1118 extern int posix_lock_file(struct file *, struct file_lock *, struct file_lock *);
1119 extern int posix_unblock_lock(struct file_lock *);
1120 extern int vfs_test_lock(struct file *, struct file_lock *);
1121 extern int vfs_lock_file(struct file *, unsigned int, struct file_lock *, struct file_lock *);
1122 extern int vfs_cancel_lock(struct file *filp, struct file_lock *fl);
1123 extern int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl);
1124 extern int __break_lease(struct inode *inode, unsigned int flags, unsigned int type);
1125 extern void lease_get_mtime(struct inode *, struct timespec *time);
1126 extern int generic_setlease(struct file *, long, struct file_lock **, void **priv);
1127 extern int vfs_setlease(struct file *, long, struct file_lock **, void **);
1128 extern int lease_modify(struct file_lock *, int, struct list_head *);
1129 struct files_struct;
1130 extern void show_fd_locks(struct seq_file *f,
1131                          struct file *filp, struct files_struct *files);
1132 #else /* !CONFIG_FILE_LOCKING */
1133 static inline int fcntl_getlk(struct file *file, unsigned int cmd,
1134                               struct flock __user *user)
1135 {
1136         return -EINVAL;
1137 }
1138 
1139 static inline int fcntl_setlk(unsigned int fd, struct file *file,
1140                               unsigned int cmd, struct flock __user *user)
1141 {
1142         return -EACCES;
1143 }
1144 
1145 #if BITS_PER_LONG == 32
1146 static inline int fcntl_getlk64(struct file *file, unsigned int cmd,
1147                                 struct flock64 __user *user)
1148 {
1149         return -EINVAL;
1150 }
1151 
1152 static inline int fcntl_setlk64(unsigned int fd, struct file *file,
1153                                 unsigned int cmd, struct flock64 __user *user)
1154 {
1155         return -EACCES;
1156 }
1157 #endif
1158 static inline int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
1159 {
1160         return -EINVAL;
1161 }
1162 
1163 static inline int fcntl_getlease(struct file *filp)
1164 {
1165         return F_UNLCK;
1166 }
1167 
1168 static inline void
1169 locks_free_lock_context(struct inode *inode)
1170 {
1171 }
1172 
1173 static inline void locks_init_lock(struct file_lock *fl)
1174 {
1175         return;
1176 }
1177 
1178 static inline void locks_copy_conflock(struct file_lock *new, struct file_lock *fl)
1179 {
1180         return;
1181 }
1182 
1183 static inline void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
1184 {
1185         return;
1186 }
1187 
1188 static inline void locks_remove_posix(struct file *filp, fl_owner_t owner)
1189 {
1190         return;
1191 }
1192 
1193 static inline void locks_remove_file(struct file *filp)
1194 {
1195         return;
1196 }
1197 
1198 static inline void posix_test_lock(struct file *filp, struct file_lock *fl)
1199 {
1200         return;
1201 }
1202 
1203 static inline int posix_lock_file(struct file *filp, struct file_lock *fl,
1204                                   struct file_lock *conflock)
1205 {
1206         return -ENOLCK;
1207 }
1208 
1209 static inline int posix_unblock_lock(struct file_lock *waiter)
1210 {
1211         return -ENOENT;
1212 }
1213 
1214 static inline int vfs_test_lock(struct file *filp, struct file_lock *fl)
1215 {
1216         return 0;
1217 }
1218 
1219 static inline int vfs_lock_file(struct file *filp, unsigned int cmd,
1220                                 struct file_lock *fl, struct file_lock *conf)
1221 {
1222         return -ENOLCK;
1223 }
1224 
1225 static inline int vfs_cancel_lock(struct file *filp, struct file_lock *fl)
1226 {
1227         return 0;
1228 }
1229 
1230 static inline int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl)
1231 {
1232         return -ENOLCK;
1233 }
1234 
1235 static inline int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
1236 {
1237         return 0;
1238 }
1239 
1240 static inline void lease_get_mtime(struct inode *inode, struct timespec *time)
1241 {
1242         return;
1243 }
1244 
1245 static inline int generic_setlease(struct file *filp, long arg,
1246                                     struct file_lock **flp, void **priv)
1247 {
1248         return -EINVAL;
1249 }
1250 
1251 static inline int vfs_setlease(struct file *filp, long arg,
1252                                struct file_lock **lease, void **priv)
1253 {
1254         return -EINVAL;
1255 }
1256 
1257 static inline int lease_modify(struct file_lock *fl, int arg,
1258                                struct list_head *dispose)
1259 {
1260         return -EINVAL;
1261 }
1262 
1263 struct files_struct;
1264 static inline void show_fd_locks(struct seq_file *f,
1265                         struct file *filp, struct files_struct *files) {}
1266 #endif /* !CONFIG_FILE_LOCKING */
1267 
1268 static inline struct inode *file_inode(const struct file *f)
1269 {
1270         return f->f_inode;
1271 }
1272 
1273 static inline struct dentry *file_dentry(const struct file *file)
1274 {
1275         struct dentry *dentry = file->f_path.dentry;
1276 
1277         if (unlikely(dentry->d_flags & DCACHE_OP_REAL))
1278                 return dentry->d_op->d_real(dentry, file_inode(file));
1279         else
1280                 return dentry;
1281 }
1282 
1283 static inline int locks_lock_file_wait(struct file *filp, struct file_lock *fl)
1284 {
1285         return locks_lock_inode_wait(file_inode(filp), fl);
1286 }
1287 
1288 struct fasync_struct {
1289         spinlock_t              fa_lock;
1290         int                     magic;
1291         int                     fa_fd;
1292         struct fasync_struct    *fa_next; /* singly linked list */
1293         struct file             *fa_file;
1294         struct rcu_head         fa_rcu;
1295 };
1296 
1297 #define FASYNC_MAGIC 0x4601
1298 
1299 /* SMP safe fasync helpers: */
1300 extern int fasync_helper(int, struct file *, int, struct fasync_struct **);
1301 extern struct fasync_struct *fasync_insert_entry(int, struct file *, struct fasync_struct **, struct fasync_struct *);
1302 extern int fasync_remove_entry(struct file *, struct fasync_struct **);
1303 extern struct fasync_struct *fasync_alloc(void);
1304 extern void fasync_free(struct fasync_struct *);
1305 
1306 /* can be called from interrupts */
1307 extern void kill_fasync(struct fasync_struct **, int, int);
1308 
1309 extern void __f_setown(struct file *filp, struct pid *, enum pid_type, int force);
1310 extern void f_setown(struct file *filp, unsigned long arg, int force);
1311 extern void f_delown(struct file *filp);
1312 extern pid_t f_getown(struct file *filp);
1313 extern int send_sigurg(struct fown_struct *fown);
1314 
1315 struct mm_struct;
1316 
1317 /*
1318  *      Umount options
1319  */
1320 
1321 #define MNT_FORCE       0x00000001      /* Attempt to forcibily umount */
1322 #define MNT_DETACH      0x00000002      /* Just detach from the tree */
1323 #define MNT_EXPIRE      0x00000004      /* Mark for expiry */
1324 #define UMOUNT_NOFOLLOW 0x00000008      /* Don't follow symlink on umount */
1325 #define UMOUNT_UNUSED   0x80000000      /* Flag guaranteed to be unused */
1326 
1327 /* sb->s_iflags */
1328 #define SB_I_CGROUPWB   0x00000001      /* cgroup-aware writeback enabled */
1329 #define SB_I_NOEXEC     0x00000002      /* Ignore executables on this fs */
1330 
1331 /* Possible states of 'frozen' field */
1332 enum {
1333         SB_UNFROZEN = 0,                /* FS is unfrozen */
1334         SB_FREEZE_WRITE = 1,            /* Writes, dir ops, ioctls frozen */
1335         SB_FREEZE_PAGEFAULT = 2,        /* Page faults stopped as well */
1336         SB_FREEZE_FS = 3,               /* For internal FS use (e.g. to stop
1337                                          * internal threads if needed) */
1338         SB_FREEZE_COMPLETE = 4,         /* ->freeze_fs finished successfully */
1339 };
1340 
1341 #define SB_FREEZE_LEVELS (SB_FREEZE_COMPLETE - 1)
1342 
1343 struct sb_writers {
1344         int                             frozen;         /* Is sb frozen? */
1345         wait_queue_head_t               wait_unfrozen;  /* for get_super_thawed() */
1346         struct percpu_rw_semaphore      rw_sem[SB_FREEZE_LEVELS];
1347 };
1348 
1349 struct super_block {
1350         struct list_head        s_list;         /* Keep this first */
1351         dev_t                   s_dev;          /* search index; _not_ kdev_t */
1352         unsigned char           s_blocksize_bits;
1353         unsigned long           s_blocksize;
1354         loff_t                  s_maxbytes;     /* Max file size */
1355         struct file_system_type *s_type;
1356         const struct super_operations   *s_op;
1357         const struct dquot_operations   *dq_op;
1358         const struct quotactl_ops       *s_qcop;
1359         const struct export_operations *s_export_op;
1360         unsigned long           s_flags;
1361         unsigned long           s_iflags;       /* internal SB_I_* flags */
1362         unsigned long           s_magic;
1363         struct dentry           *s_root;
1364         struct rw_semaphore     s_umount;
1365         int                     s_count;
1366         atomic_t                s_active;
1367 #ifdef CONFIG_SECURITY
1368         void                    *s_security;
1369 #endif
1370         const struct xattr_handler **s_xattr;
1371 
1372         const struct fscrypt_operations *s_cop;
1373 
1374         struct hlist_bl_head    s_anon;         /* anonymous dentries for (nfs) exporting */
1375         struct list_head        s_mounts;       /* list of mounts; _not_ for fs use */
1376         struct block_device     *s_bdev;
1377         struct backing_dev_info *s_bdi;
1378         struct mtd_info         *s_mtd;
1379         struct hlist_node       s_instances;
1380         unsigned int            s_quota_types;  /* Bitmask of supported quota types */
1381         struct quota_info       s_dquot;        /* Diskquota specific options */
1382 
1383         struct sb_writers       s_writers;
1384 
1385         char s_id[32];                          /* Informational name */
1386         u8 s_uuid[16];                          /* UUID */
1387 
1388         void                    *s_fs_info;     /* Filesystem private info */
1389         unsigned int            s_max_links;
1390         fmode_t                 s_mode;
1391 
1392         /* Granularity of c/m/atime in ns.
1393            Cannot be worse than a second */
1394         u32                s_time_gran;
1395 
1396         /*
1397          * The next field is for VFS *only*. No filesystems have any business
1398          * even looking at it. You had been warned.
1399          */
1400         struct mutex s_vfs_rename_mutex;        /* Kludge */
1401 
1402         /*
1403          * Filesystem subtype.  If non-empty the filesystem type field
1404          * in /proc/mounts will be "type.subtype"
1405          */
1406         char *s_subtype;
1407 
1408         /*
1409          * Saved mount options for lazy filesystems using
1410          * generic_show_options()
1411          */
1412         char __rcu *s_options;
1413         const struct dentry_operations *s_d_op; /* default d_op for dentries */
1414 
1415         /*
1416          * Saved pool identifier for cleancache (-1 means none)
1417          */
1418         int cleancache_poolid;
1419 
1420         struct shrinker s_shrink;       /* per-sb shrinker handle */
1421 
1422         /* Number of inodes with nlink == 0 but still referenced */
1423         atomic_long_t s_remove_count;
1424 
1425         /* Being remounted read-only */
1426         int s_readonly_remount;
1427 
1428         /* AIO completions deferred from interrupt context */
1429         struct workqueue_struct *s_dio_done_wq;
1430         struct hlist_head s_pins;
1431 
1432         /*
1433          * Keep the lru lists last in the structure so they always sit on their
1434          * own individual cachelines.
1435          */
1436         struct list_lru         s_dentry_lru ____cacheline_aligned_in_smp;
1437         struct list_lru         s_inode_lru ____cacheline_aligned_in_smp;
1438         struct rcu_head         rcu;
1439         struct work_struct      destroy_work;
1440 
1441         struct mutex            s_sync_lock;    /* sync serialisation lock */
1442 
1443         /*
1444          * Indicates how deep in a filesystem stack this SB is
1445          */
1446         int s_stack_depth;
1447 
1448         /* s_inode_list_lock protects s_inodes */
1449         spinlock_t              s_inode_list_lock ____cacheline_aligned_in_smp;
1450         struct list_head        s_inodes;       /* all inodes */
1451 };
1452 
1453 extern struct timespec current_fs_time(struct super_block *sb);
1454 
1455 /*
1456  * Snapshotting support.
1457  */
1458 
1459 void __sb_end_write(struct super_block *sb, int level);
1460 int __sb_start_write(struct super_block *sb, int level, bool wait);
1461 
1462 #define __sb_writers_acquired(sb, lev)  \
1463         percpu_rwsem_acquire(&(sb)->s_writers.rw_sem[(lev)-1], 1, _THIS_IP_)
1464 #define __sb_writers_release(sb, lev)   \
1465         percpu_rwsem_release(&(sb)->s_writers.rw_sem[(lev)-1], 1, _THIS_IP_)
1466 
1467 /**
1468  * sb_end_write - drop write access to a superblock
1469  * @sb: the super we wrote to
1470  *
1471  * Decrement number of writers to the filesystem. Wake up possible waiters
1472  * wanting to freeze the filesystem.
1473  */
1474 static inline void sb_end_write(struct super_block *sb)
1475 {
1476         __sb_end_write(sb, SB_FREEZE_WRITE);
1477 }
1478 
1479 /**
1480  * sb_end_pagefault - drop write access to a superblock from a page fault
1481  * @sb: the super we wrote to
1482  *
1483  * Decrement number of processes handling write page fault to the filesystem.
1484  * Wake up possible waiters wanting to freeze the filesystem.
1485  */
1486 static inline void sb_end_pagefault(struct super_block *sb)
1487 {
1488         __sb_end_write(sb, SB_FREEZE_PAGEFAULT);
1489 }
1490 
1491 /**
1492  * sb_end_intwrite - drop write access to a superblock for internal fs purposes
1493  * @sb: the super we wrote to
1494  *
1495  * Decrement fs-internal number of writers to the filesystem.  Wake up possible
1496  * waiters wanting to freeze the filesystem.
1497  */
1498 static inline void sb_end_intwrite(struct super_block *sb)
1499 {
1500         __sb_end_write(sb, SB_FREEZE_FS);
1501 }
1502 
1503 /**
1504  * sb_start_write - get write access to a superblock
1505  * @sb: the super we write to
1506  *
1507  * When a process wants to write data or metadata to a file system (i.e. dirty
1508  * a page or an inode), it should embed the operation in a sb_start_write() -
1509  * sb_end_write() pair to get exclusion against file system freezing. This
1510  * function increments number of writers preventing freezing. If the file
1511  * system is already frozen, the function waits until the file system is
1512  * thawed.
1513  *
1514  * Since freeze protection behaves as a lock, users have to preserve
1515  * ordering of freeze protection and other filesystem locks. Generally,
1516  * freeze protection should be the outermost lock. In particular, we have:
1517  *
1518  * sb_start_write
1519  *   -> i_mutex                 (write path, truncate, directory ops, ...)
1520  *   -> s_umount                (freeze_super, thaw_super)
1521  */
1522 static inline void sb_start_write(struct super_block *sb)
1523 {
1524         __sb_start_write(sb, SB_FREEZE_WRITE, true);
1525 }
1526 
1527 static inline int sb_start_write_trylock(struct super_block *sb)
1528 {
1529         return __sb_start_write(sb, SB_FREEZE_WRITE, false);
1530 }
1531 
1532 /**
1533  * sb_start_pagefault - get write access to a superblock from a page fault
1534  * @sb: the super we write to
1535  *
1536  * When a process starts handling write page fault, it should embed the
1537  * operation into sb_start_pagefault() - sb_end_pagefault() pair to get
1538  * exclusion against file system freezing. This is needed since the page fault
1539  * is going to dirty a page. This function increments number of running page
1540  * faults preventing freezing. If the file system is already frozen, the
1541  * function waits until the file system is thawed.
1542  *
1543  * Since page fault freeze protection behaves as a lock, users have to preserve
1544  * ordering of freeze protection and other filesystem locks. It is advised to
1545  * put sb_start_pagefault() close to mmap_sem in lock ordering. Page fault
1546  * handling code implies lock dependency:
1547  *
1548  * mmap_sem
1549  *   -> sb_start_pagefault
1550  */
1551 static inline void sb_start_pagefault(struct super_block *sb)
1552 {
1553         __sb_start_write(sb, SB_FREEZE_PAGEFAULT, true);
1554 }
1555 
1556 /*
1557  * sb_start_intwrite - get write access to a superblock for internal fs purposes
1558  * @sb: the super we write to
1559  *
1560  * This is the third level of protection against filesystem freezing. It is
1561  * free for use by a filesystem. The only requirement is that it must rank
1562  * below sb_start_pagefault.
1563  *
1564  * For example filesystem can call sb_start_intwrite() when starting a
1565  * transaction which somewhat eases handling of freezing for internal sources
1566  * of filesystem changes (internal fs threads, discarding preallocation on file
1567  * close, etc.).
1568  */
1569 static inline void sb_start_intwrite(struct super_block *sb)
1570 {
1571         __sb_start_write(sb, SB_FREEZE_FS, true);
1572 }
1573 
1574 
1575 extern bool inode_owner_or_capable(const struct inode *inode);
1576 
1577 /*
1578  * VFS helper functions..
1579  */
1580 extern int vfs_create(struct inode *, struct dentry *, umode_t, bool);
1581 extern int vfs_mkdir(struct inode *, struct dentry *, umode_t);
1582 extern int vfs_mknod(struct inode *, struct dentry *, umode_t, dev_t);
1583 extern int vfs_symlink(struct inode *, struct dentry *, const char *);
1584 extern int vfs_link(struct dentry *, struct inode *, struct dentry *, struct inode **);
1585 extern int vfs_rmdir(struct inode *, struct dentry *);
1586 extern int vfs_unlink(struct inode *, struct dentry *, struct inode **);
1587 extern int vfs_rename(struct inode *, struct dentry *, struct inode *, struct dentry *, struct inode **, unsigned int);
1588 extern int vfs_whiteout(struct inode *, struct dentry *);
1589 
1590 /*
1591  * VFS file helper functions.
1592  */
1593 extern void inode_init_owner(struct inode *inode, const struct inode *dir,
1594                         umode_t mode);
1595 /*
1596  * VFS FS_IOC_FIEMAP helper definitions.
1597  */
1598 struct fiemap_extent_info {
1599         unsigned int fi_flags;          /* Flags as passed from user */
1600         unsigned int fi_extents_mapped; /* Number of mapped extents */
1601         unsigned int fi_extents_max;    /* Size of fiemap_extent array */
1602         struct fiemap_extent __user *fi_extents_start; /* Start of
1603                                                         fiemap_extent array */
1604 };
1605 int fiemap_fill_next_extent(struct fiemap_extent_info *info, u64 logical,
1606                             u64 phys, u64 len, u32 flags);
1607 int fiemap_check_flags(struct fiemap_extent_info *fieinfo, u32 fs_flags);
1608 
1609 /*
1610  * File types
1611  *
1612  * NOTE! These match bits 12..15 of stat.st_mode
1613  * (ie "(i_mode >> 12) & 15").
1614  */
1615 #define DT_UNKNOWN      0
1616 #define DT_FIFO         1
1617 #define DT_CHR          2
1618 #define DT_DIR          4
1619 #define DT_BLK          6
1620 #define DT_REG          8
1621 #define DT_LNK          10
1622 #define DT_SOCK         12
1623 #define DT_WHT          14
1624 
1625 /*
1626  * This is the "filldir" function type, used by readdir() to let
1627  * the kernel specify what kind of dirent layout it wants to have.
1628  * This allows the kernel to read directories into kernel space or
1629  * to have different dirent layouts depending on the binary type.
1630  */
1631 struct dir_context;
1632 typedef int (*filldir_t)(struct dir_context *, const char *, int, loff_t, u64,
1633                          unsigned);
1634 
1635 struct dir_context {
1636         const filldir_t actor;
1637         loff_t pos;
1638 };
1639 
1640 struct block_device_operations;
1641 
1642 /* These macros are for out of kernel modules to test that
1643  * the kernel supports the unlocked_ioctl and compat_ioctl
1644  * fields in struct file_operations. */
1645 #define HAVE_COMPAT_IOCTL 1
1646 #define HAVE_UNLOCKED_IOCTL 1
1647 
1648 /*
1649  * These flags let !MMU mmap() govern direct device mapping vs immediate
1650  * copying more easily for MAP_PRIVATE, especially for ROM filesystems.
1651  *
1652  * NOMMU_MAP_COPY:      Copy can be mapped (MAP_PRIVATE)
1653  * NOMMU_MAP_DIRECT:    Can be mapped directly (MAP_SHARED)
1654  * NOMMU_MAP_READ:      Can be mapped for reading
1655  * NOMMU_MAP_WRITE:     Can be mapped for writing
1656  * NOMMU_MAP_EXEC:      Can be mapped for execution
1657  */
1658 #define NOMMU_MAP_COPY          0x00000001
1659 #define NOMMU_MAP_DIRECT        0x00000008
1660 #define NOMMU_MAP_READ          VM_MAYREAD
1661 #define NOMMU_MAP_WRITE         VM_MAYWRITE
1662 #define NOMMU_MAP_EXEC          VM_MAYEXEC
1663 
1664 #define NOMMU_VMFLAGS \
1665         (NOMMU_MAP_READ | NOMMU_MAP_WRITE | NOMMU_MAP_EXEC)
1666 
1667 
1668 struct iov_iter;
1669 
1670 struct file_operations {
1671         struct module *owner;
1672         loff_t (*llseek) (struct file *, loff_t, int);
1673         ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);
1674         ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
1675         ssize_t (*read_iter) (struct kiocb *, struct iov_iter *);
1676         ssize_t (*write_iter) (struct kiocb *, struct iov_iter *);
1677         int (*iterate) (struct file *, struct dir_context *);
1678         int (*iterate_shared) (struct file *, struct dir_context *);
1679         unsigned int (*poll) (struct file *, struct poll_table_struct *);
1680         long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
1681         long (*compat_ioctl) (struct file *, unsigned int, unsigned long);
1682         int (*mmap) (struct file *, struct vm_area_struct *);
1683         int (*open) (struct inode *, struct file *);
1684         int (*flush) (struct file *, fl_owner_t id);
1685         int (*release) (struct inode *, struct file *);
1686         int (*fsync) (struct file *, loff_t, loff_t, int datasync);
1687         int (*aio_fsync) (struct kiocb *, int datasync);
1688         int (*fasync) (int, struct file *, int);
1689         int (*lock) (struct file *, int, struct file_lock *);
1690         ssize_t (*sendpage) (struct file *, struct page *, int, size_t, loff_t *, int);
1691         unsigned long (*get_unmapped_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
1692         int (*check_flags)(int);
1693         int (*flock) (struct file *, int, struct file_lock *);
1694         ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, loff_t *, size_t, unsigned int);
1695         ssize_t (*splice_read)(struct file *, loff_t *, struct pipe_inode_info *, size_t, unsigned int);
1696         int (*setlease)(struct file *, long, struct file_lock **, void **);
1697         long (*fallocate)(struct file *file, int mode, loff_t offset,
1698                           loff_t len);
1699         void (*show_fdinfo)(struct seq_file *m, struct file *f);
1700 #ifndef CONFIG_MMU
1701         unsigned (*mmap_capabilities)(struct file *);
1702 #endif
1703         ssize_t (*copy_file_range)(struct file *, loff_t, struct file *,
1704                         loff_t, size_t, unsigned int);
1705         int (*clone_file_range)(struct file *, loff_t, struct file *, loff_t,
1706                         u64);
1707         ssize_t (*dedupe_file_range)(struct file *, u64, u64, struct file *,
1708                         u64);
1709 };
1710 
1711 struct inode_operations {
1712         struct dentry * (*lookup) (struct inode *,struct dentry *, unsigned int);
1713         const char * (*get_link) (struct dentry *, struct inode *, struct delayed_call *);
1714         int (*permission) (struct inode *, int);
1715         struct posix_acl * (*get_acl)(struct inode *, int);
1716 
1717         int (*readlink) (struct dentry *, char __user *,int);
1718 
1719         int (*create) (struct inode *,struct dentry *, umode_t, bool);
1720         int (*link) (struct dentry *,struct inode *,struct dentry *);
1721         int (*unlink) (struct inode *,struct dentry *);
1722         int (*symlink) (struct inode *,struct dentry *,const char *);
1723         int (*mkdir) (struct inode *,struct dentry *,umode_t);
1724         int (*rmdir) (struct inode *,struct dentry *);
1725         int (*mknod) (struct inode *,struct dentry *,umode_t,dev_t);
1726         int (*rename) (struct inode *, struct dentry *,
1727                         struct inode *, struct dentry *);
1728         int (*rename2) (struct inode *, struct dentry *,
1729                         struct inode *, struct dentry *, unsigned int);
1730         int (*setattr) (struct dentry *, struct iattr *);
1731         int (*getattr) (struct vfsmount *mnt, struct dentry *, struct kstat *);
1732         int (*setxattr) (struct dentry *, struct inode *,
1733                          const char *, const void *, size_t, int);
1734         ssize_t (*getxattr) (struct dentry *, struct inode *,
1735                              const char *, void *, size_t);
1736         ssize_t (*listxattr) (struct dentry *, char *, size_t);
1737         int (*removexattr) (struct dentry *, const char *);
1738         int (*fiemap)(struct inode *, struct fiemap_extent_info *, u64 start,
1739                       u64 len);
1740         int (*update_time)(struct inode *, struct timespec *, int);
1741         int (*atomic_open)(struct inode *, struct dentry *,
1742                            struct file *, unsigned open_flag,
1743                            umode_t create_mode, int *opened);
1744         int (*tmpfile) (struct inode *, struct dentry *, umode_t);
1745         int (*set_acl)(struct inode *, struct posix_acl *, int);
1746 } ____cacheline_aligned;
1747 
1748 ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector,
1749                               unsigned long nr_segs, unsigned long fast_segs,
1750                               struct iovec *fast_pointer,
1751                               struct iovec **ret_pointer);
1752 
1753 extern ssize_t __vfs_read(struct file *, char __user *, size_t, loff_t *);
1754 extern ssize_t __vfs_write(struct file *, const char __user *, size_t, loff_t *);
1755 extern ssize_t vfs_read(struct file *, char __user *, size_t, loff_t *);
1756 extern ssize_t vfs_write(struct file *, const char __user *, size_t, loff_t *);
1757 extern ssize_t vfs_readv(struct file *, const struct iovec __user *,
1758                 unsigned long, loff_t *, int);
1759 extern ssize_t vfs_writev(struct file *, const struct iovec __user *,
1760                 unsigned long, loff_t *, int);
1761 extern ssize_t vfs_copy_file_range(struct file *, loff_t , struct file *,
1762                                    loff_t, size_t, unsigned int);
1763 extern int vfs_clone_file_range(struct file *file_in, loff_t pos_in,
1764                 struct file *file_out, loff_t pos_out, u64 len);
1765 extern int vfs_dedupe_file_range(struct file *file,
1766                                  struct file_dedupe_range *same);
1767 
1768 struct super_operations {
1769         struct inode *(*alloc_inode)(struct super_block *sb);
1770         void (*destroy_inode)(struct inode *);
1771 
1772         void (*dirty_inode) (struct inode *, int flags);
1773         int (*write_inode) (struct inode *, struct writeback_control *wbc);
1774         int (*drop_inode) (struct inode *);
1775         void (*evict_inode) (struct inode *);
1776         void (*put_super) (struct super_block *);
1777         int (*sync_fs)(struct super_block *sb, int wait);
1778         int (*freeze_super) (struct super_block *);
1779         int (*freeze_fs) (struct super_block *);
1780         int (*thaw_super) (struct super_block *);
1781         int (*unfreeze_fs) (struct super_block *);
1782         int (*statfs) (struct dentry *, struct kstatfs *);
1783         int (*remount_fs) (struct super_block *, int *, char *);
1784         void (*umount_begin) (struct super_block *);
1785 
1786         int (*show_options)(struct seq_file *, struct dentry *);
1787         int (*show_devname)(struct seq_file *, struct dentry *);
1788         int (*show_path)(struct seq_file *, struct dentry *);
1789         int (*show_stats)(struct seq_file *, struct dentry *);
1790 #ifdef CONFIG_QUOTA
1791         ssize_t (*quota_read)(struct super_block *, int, char *, size_t, loff_t);
1792         ssize_t (*quota_write)(struct super_block *, int, const char *, size_t, loff_t);
1793         struct dquot **(*get_dquots)(struct inode *);
1794 #endif
1795         int (*bdev_try_to_free_page)(struct super_block*, struct page*, gfp_t);
1796         long (*nr_cached_objects)(struct super_block *,
1797                                   struct shrink_control *);
1798         long (*free_cached_objects)(struct super_block *,
1799                                     struct shrink_control *);
1800 };
1801 
1802 /*
1803  * Inode flags - they have no relation to superblock flags now
1804  */
1805 #define S_SYNC          1       /* Writes are synced at once */
1806 #define S_NOATIME       2       /* Do not update access times */
1807 #define S_APPEND        4       /* Append-only file */
1808 #define S_IMMUTABLE     8       /* Immutable file */
1809 #define S_DEAD          16      /* removed, but still open directory */
1810 #define S_NOQUOTA       32      /* Inode is not counted to quota */
1811 #define S_DIRSYNC       64      /* Directory modifications are synchronous */
1812 #define S_NOCMTIME      128     /* Do not update file c/mtime */
1813 #define S_SWAPFILE      256     /* Do not truncate: swapon got its bmaps */
1814 #define S_PRIVATE       512     /* Inode is fs-internal */
1815 #define S_IMA           1024    /* Inode has an associated IMA struct */
1816 #define S_AUTOMOUNT     2048    /* Automount/referral quasi-directory */
1817 #define S_NOSEC         4096    /* no suid or xattr security attributes */
1818 #ifdef CONFIG_FS_DAX
1819 #define S_DAX           8192    /* Direct Access, avoiding the page cache */
1820 #else
1821 #define S_DAX           0       /* Make all the DAX code disappear */
1822 #endif
1823 
1824 /*
1825  * Note that nosuid etc flags are inode-specific: setting some file-system
1826  * flags just means all the inodes inherit those flags by default. It might be
1827  * possible to override it selectively if you really wanted to with some
1828  * ioctl() that is not currently implemented.
1829  *
1830  * Exception: MS_RDONLY is always applied to the entire file system.
1831  *
1832  * Unfortunately, it is possible to change a filesystems flags with it mounted
1833  * with files in use.  This means that all of the inodes will not have their
1834  * i_flags updated.  Hence, i_flags no longer inherit the superblock mount
1835  * flags, so these have to be checked separately. -- rmk@arm.uk.linux.org
1836  */
1837 #define __IS_FLG(inode, flg)    ((inode)->i_sb->s_flags & (flg))
1838 
1839 #define IS_RDONLY(inode)        ((inode)->i_sb->s_flags & MS_RDONLY)
1840 #define IS_SYNC(inode)          (__IS_FLG(inode, MS_SYNCHRONOUS) || \
1841                                         ((inode)->i_flags & S_SYNC))
1842 #define IS_DIRSYNC(inode)       (__IS_FLG(inode, MS_SYNCHRONOUS|MS_DIRSYNC) || \
1843                                         ((inode)->i_flags & (S_SYNC|S_DIRSYNC)))
1844 #define IS_MANDLOCK(inode)      __IS_FLG(inode, MS_MANDLOCK)
1845 #define IS_NOATIME(inode)       __IS_FLG(inode, MS_RDONLY|MS_NOATIME)
1846 #define IS_I_VERSION(inode)     __IS_FLG(inode, MS_I_VERSION)
1847 
1848 #define IS_NOQUOTA(inode)       ((inode)->i_flags & S_NOQUOTA)
1849 #define IS_APPEND(inode)        ((inode)->i_flags & S_APPEND)
1850 #define IS_IMMUTABLE(inode)     ((inode)->i_flags & S_IMMUTABLE)
1851 #define IS_POSIXACL(inode)      __IS_FLG(inode, MS_POSIXACL)
1852 
1853 #define IS_DEADDIR(inode)       ((inode)->i_flags & S_DEAD)
1854 #define IS_NOCMTIME(inode)      ((inode)->i_flags & S_NOCMTIME)
1855 #define IS_SWAPFILE(inode)      ((inode)->i_flags & S_SWAPFILE)
1856 #define IS_PRIVATE(inode)       ((inode)->i_flags & S_PRIVATE)
1857 #define IS_IMA(inode)           ((inode)->i_flags & S_IMA)
1858 #define IS_AUTOMOUNT(inode)     ((inode)->i_flags & S_AUTOMOUNT)
1859 #define IS_NOSEC(inode)         ((inode)->i_flags & S_NOSEC)
1860 #define IS_DAX(inode)           ((inode)->i_flags & S_DAX)
1861 
1862 #define IS_WHITEOUT(inode)      (S_ISCHR(inode->i_mode) && \
1863                                  (inode)->i_rdev == WHITEOUT_DEV)
1864 
1865 /*
1866  * Inode state bits.  Protected by inode->i_lock
1867  *
1868  * Three bits determine the dirty state of the inode, I_DIRTY_SYNC,
1869  * I_DIRTY_DATASYNC and I_DIRTY_PAGES.
1870  *
1871  * Four bits define the lifetime of an inode.  Initially, inodes are I_NEW,
1872  * until that flag is cleared.  I_WILL_FREE, I_FREEING and I_CLEAR are set at
1873  * various stages of removing an inode.
1874  *
1875  * Two bits are used for locking and completion notification, I_NEW and I_SYNC.
1876  *
1877  * I_DIRTY_SYNC         Inode is dirty, but doesn't have to be written on
1878  *                      fdatasync().  i_atime is the usual cause.
1879  * I_DIRTY_DATASYNC     Data-related inode changes pending. We keep track of
1880  *                      these changes separately from I_DIRTY_SYNC so that we
1881  *                      don't have to write inode on fdatasync() when only
1882  *                      mtime has changed in it.
1883  * I_DIRTY_PAGES        Inode has dirty pages.  Inode itself may be clean.
1884  * I_NEW                Serves as both a mutex and completion notification.
1885  *                      New inodes set I_NEW.  If two processes both create
1886  *                      the same inode, one of them will release its inode and
1887  *                      wait for I_NEW to be released before returning.
1888  *                      Inodes in I_WILL_FREE, I_FREEING or I_CLEAR state can
1889  *                      also cause waiting on I_NEW, without I_NEW actually
1890  *                      being set.  find_inode() uses this to prevent returning
1891  *                      nearly-dead inodes.
1892  * I_WILL_FREE          Must be set when calling write_inode_now() if i_count
1893  *                      is zero.  I_FREEING must be set when I_WILL_FREE is
1894  *                      cleared.
1895  * I_FREEING            Set when inode is about to be freed but still has dirty
1896  *                      pages or buffers attached or the inode itself is still
1897  *                      dirty.
1898  * I_CLEAR              Added by clear_inode().  In this state the inode is
1899  *                      clean and can be destroyed.  Inode keeps I_FREEING.
1900  *
1901  *                      Inodes that are I_WILL_FREE, I_FREEING or I_CLEAR are
1902  *                      prohibited for many purposes.  iget() must wait for
1903  *                      the inode to be completely released, then create it
1904  *                      anew.  Other functions will just ignore such inodes,
1905  *                      if appropriate.  I_NEW is used for waiting.
1906  *
1907  * I_SYNC               Writeback of inode is running. The bit is set during
1908  *                      data writeback, and cleared with a wakeup on the bit
1909  *                      address once it is done. The bit is also used to pin
1910  *                      the inode in memory for flusher thread.
1911  *
1912  * I_REFERENCED         Marks the inode as recently references on the LRU list.
1913  *
1914  * I_DIO_WAKEUP         Never set.  Only used as a key for wait_on_bit().
1915  *
1916  * I_WB_SWITCH          Cgroup bdi_writeback switching in progress.  Used to
1917  *                      synchronize competing switching instances and to tell
1918  *                      wb stat updates to grab mapping->tree_lock.  See
1919  *                      inode_switch_wb_work_fn() for details.
1920  *
1921  * Q: What is the difference between I_WILL_FREE and I_FREEING?
1922  */
1923 #define I_DIRTY_SYNC            (1 << 0)
1924 #define I_DIRTY_DATASYNC        (1 << 1)
1925 #define I_DIRTY_PAGES           (1 << 2)
1926 #define __I_NEW                 3
1927 #define I_NEW                   (1 << __I_NEW)
1928 #define I_WILL_FREE             (1 << 4)
1929 #define I_FREEING               (1 << 5)
1930 #define I_CLEAR                 (1 << 6)
1931 #define __I_SYNC                7
1932 #define I_SYNC                  (1 << __I_SYNC)
1933 #define I_REFERENCED            (1 << 8)
1934 #define __I_DIO_WAKEUP          9
1935 #define I_DIO_WAKEUP            (1 << __I_DIO_WAKEUP)
1936 #define I_LINKABLE              (1 << 10)
1937 #define I_DIRTY_TIME            (1 << 11)
1938 #define __I_DIRTY_TIME_EXPIRED  12
1939 #define I_DIRTY_TIME_EXPIRED    (1 << __I_DIRTY_TIME_EXPIRED)
1940 #define I_WB_SWITCH             (1 << 13)
1941 
1942 #define I_DIRTY (I_DIRTY_SYNC | I_DIRTY_DATASYNC | I_DIRTY_PAGES)
1943 #define I_DIRTY_ALL (I_DIRTY | I_DIRTY_TIME)
1944 
1945 extern void __mark_inode_dirty(struct inode *, int);
1946 static inline void mark_inode_dirty(struct inode *inode)
1947 {
1948         __mark_inode_dirty(inode, I_DIRTY);
1949 }
1950 
1951 static inline void mark_inode_dirty_sync(struct inode *inode)
1952 {
1953         __mark_inode_dirty(inode, I_DIRTY_SYNC);
1954 }
1955 
1956 extern void inc_nlink(struct inode *inode);
1957 extern void drop_nlink(struct inode *inode);
1958 extern void clear_nlink(struct inode *inode);
1959 extern void set_nlink(struct inode *inode, unsigned int nlink);
1960 
1961 static inline void inode_inc_link_count(struct inode *inode)
1962 {
1963         inc_nlink(inode);
1964         mark_inode_dirty(inode);
1965 }
1966 
1967 static inline void inode_dec_link_count(struct inode *inode)
1968 {
1969         drop_nlink(inode);
1970         mark_inode_dirty(inode);
1971 }
1972 
1973 /**
1974  * inode_inc_iversion - increments i_version
1975  * @inode: inode that need to be updated
1976  *
1977  * Every time the inode is modified, the i_version field will be incremented.
1978  * The filesystem has to be mounted with i_version flag
1979  */
1980 
1981 static inline void inode_inc_iversion(struct inode *inode)
1982 {
1983        spin_lock(&inode->i_lock);
1984        inode->i_version++;
1985        spin_unlock(&inode->i_lock);
1986 }
1987 
1988 enum file_time_flags {
1989         S_ATIME = 1,
1990         S_MTIME = 2,
1991         S_CTIME = 4,
1992         S_VERSION = 8,
1993 };
1994 
1995 extern bool atime_needs_update(const struct path *, struct inode *);
1996 extern void touch_atime(const struct path *);
1997 static inline void file_accessed(struct file *file)
1998 {
1999         if (!(file->f_flags & O_NOATIME))
2000                 touch_atime(&file->f_path);
2001 }
2002 
2003 int sync_inode(struct inode *inode, struct writeback_control *wbc);
2004 int sync_inode_metadata(struct inode *inode, int wait);
2005 
2006 struct file_system_type {
2007         const char *name;
2008         int fs_flags;
2009 #define FS_REQUIRES_DEV         1 
2010 #define FS_BINARY_MOUNTDATA     2
2011 #define FS_HAS_SUBTYPE          4
2012 #define FS_USERNS_MOUNT         8       /* Can be mounted by userns root */
2013 #define FS_USERNS_DEV_MOUNT     16 /* A userns mount does not imply MNT_NODEV */
2014 #define FS_USERNS_VISIBLE       32      /* FS must already be visible */
2015 #define FS_RENAME_DOES_D_MOVE   32768   /* FS will handle d_move() during rename() internally. */
2016         struct dentry *(*mount) (struct file_system_type *, int,
2017                        const char *, void *);
2018         void (*kill_sb) (struct super_block *);
2019         struct module *owner;
2020         struct file_system_type * next;
2021         struct hlist_head fs_supers;
2022 
2023         struct lock_class_key s_lock_key;
2024         struct lock_class_key s_umount_key;
2025         struct lock_class_key s_vfs_rename_key;
2026         struct lock_class_key s_writers_key[SB_FREEZE_LEVELS];
2027 
2028         struct lock_class_key i_lock_key;
2029         struct lock_class_key i_mutex_key;
2030         struct lock_class_key i_mutex_dir_key;
2031 };
2032 
2033 #define MODULE_ALIAS_FS(NAME) MODULE_ALIAS("fs-" NAME)
2034 
2035 extern struct dentry *mount_ns(struct file_system_type *fs_type, int flags,
2036         void *data, int (*fill_super)(struct super_block *, void *, int));
2037 extern struct dentry *mount_bdev(struct file_system_type *fs_type,
2038         int flags, const char *dev_name, void *data,
2039         int (*fill_super)(struct super_block *, void *, int));
2040 extern struct dentry *mount_single(struct file_system_type *fs_type,
2041         int flags, void *data,
2042         int (*fill_super)(struct super_block *, void *, int));
2043 extern struct dentry *mount_nodev(struct file_system_type *fs_type,
2044         int flags, void *data,
2045         int (*fill_super)(struct super_block *, void *, int));
2046 extern struct dentry *mount_subtree(struct vfsmount *mnt, const char *path);
2047 void generic_shutdown_super(struct super_block *sb);
2048 void kill_block_super(struct super_block *sb);
2049 void kill_anon_super(struct super_block *sb);
2050 void kill_litter_super(struct super_block *sb);
2051 void deactivate_super(struct super_block *sb);
2052 void deactivate_locked_super(struct super_block *sb);
2053 int set_anon_super(struct super_block *s, void *data);
2054 int get_anon_bdev(dev_t *);
2055 void free_anon_bdev(dev_t);
2056 struct super_block *sget(struct file_system_type *type,
2057                         int (*test)(struct super_block *,void *),
2058                         int (*set)(struct super_block *,void *),
2059                         int flags, void *data);
2060 extern struct dentry *mount_pseudo(struct file_system_type *, char *,
2061         const struct super_operations *ops,
2062         const struct dentry_operations *dops,
2063         unsigned long);
2064 
2065 /* Alas, no aliases. Too much hassle with bringing module.h everywhere */
2066 #define fops_get(fops) \
2067         (((fops) && try_module_get((fops)->owner) ? (fops) : NULL))
2068 #define fops_put(fops) \
2069         do { if (fops) module_put((fops)->owner); } while(0)
2070 /*
2071  * This one is to be used *ONLY* from ->open() instances.
2072  * fops must be non-NULL, pinned down *and* module dependencies
2073  * should be sufficient to pin the caller down as well.
2074  */
2075 #define replace_fops(f, fops) \
2076         do {    \
2077                 struct file *__file = (f); \
2078                 fops_put(__file->f_op); \
2079                 BUG_ON(!(__file->f_op = (fops))); \
2080         } while(0)
2081 
2082 extern int register_filesystem(struct file_system_type *);
2083 extern int unregister_filesystem(struct file_system_type *);
2084 extern struct vfsmount *kern_mount_data(struct file_system_type *, void *data);
2085 #define kern_mount(type) kern_mount_data(type, NULL)
2086 extern void kern_unmount(struct vfsmount *mnt);
2087 extern int may_umount_tree(struct vfsmount *);
2088 extern int may_umount(struct vfsmount *);
2089 extern long do_mount(const char *, const char __user *,
2090                      const char *, unsigned long, void *);
2091 extern struct vfsmount *collect_mounts(struct path *);
2092 extern void drop_collected_mounts(struct vfsmount *);
2093 extern int iterate_mounts(int (*)(struct vfsmount *, void *), void *,
2094                           struct vfsmount *);
2095 extern int vfs_statfs(struct path *, struct kstatfs *);
2096 extern int user_statfs(const char __user *, struct kstatfs *);
2097 extern int fd_statfs(int, struct kstatfs *);
2098 extern int vfs_ustat(dev_t, struct kstatfs *);
2099 extern int freeze_super(struct super_block *super);
2100 extern int thaw_super(struct super_block *super);
2101 extern bool our_mnt(struct vfsmount *mnt);
2102 
2103 extern int current_umask(void);
2104 
2105 extern void ihold(struct inode * inode);
2106 extern void iput(struct inode *);
2107 extern int generic_update_time(struct inode *, struct timespec *, int);
2108 
2109 /* /sys/fs */
2110 extern struct kobject *fs_kobj;
2111 
2112 #define MAX_RW_COUNT (INT_MAX & PAGE_MASK)
2113 
2114 #ifdef CONFIG_MANDATORY_FILE_LOCKING
2115 extern int locks_mandatory_locked(struct file *);
2116 extern int locks_mandatory_area(struct inode *, struct file *, loff_t, loff_t, unsigned char);
2117 
2118 /*
2119  * Candidates for mandatory locking have the setgid bit set
2120  * but no group execute bit -  an otherwise meaningless combination.
2121  */
2122 
2123 static inline int __mandatory_lock(struct inode *ino)
2124 {
2125         return (ino->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID;
2126 }
2127 
2128 /*
2129  * ... and these candidates should be on MS_MANDLOCK mounted fs,
2130  * otherwise these will be advisory locks
2131  */
2132 
2133 static inline int mandatory_lock(struct inode *ino)
2134 {
2135         return IS_MANDLOCK(ino) && __mandatory_lock(ino);
2136 }
2137 
2138 static inline int locks_verify_locked(struct file *file)
2139 {
2140         if (mandatory_lock(file_inode(file)))
2141                 return locks_mandatory_locked(file);
2142         return 0;
2143 }
2144 
2145 static inline int locks_verify_truncate(struct inode *inode,
2146                                     struct file *f,
2147                                     loff_t size)
2148 {
2149         if (!inode->i_flctx || !mandatory_lock(inode))
2150                 return 0;
2151 
2152         if (size < inode->i_size) {
2153                 return locks_mandatory_area(inode, f, size, inode->i_size - 1,
2154                                 F_WRLCK);
2155         } else {
2156                 return locks_mandatory_area(inode, f, inode->i_size, size - 1,
2157                                 F_WRLCK);
2158         }
2159 }
2160 
2161 #else /* !CONFIG_MANDATORY_FILE_LOCKING */
2162 
2163 static inline int locks_mandatory_locked(struct file *file)
2164 {
2165         return 0;
2166 }
2167 
2168 static inline int locks_mandatory_area(struct inode *inode, struct file *filp,
2169                                        loff_t start, loff_t end, unsigned char type)
2170 {
2171         return 0;
2172 }
2173 
2174 static inline int __mandatory_lock(struct inode *inode)
2175 {
2176         return 0;
2177 }
2178 
2179 static inline int mandatory_lock(struct inode *inode)
2180 {
2181         return 0;
2182 }
2183 
2184 static inline int locks_verify_locked(struct file *file)
2185 {
2186         return 0;
2187 }
2188 
2189 static inline int locks_verify_truncate(struct inode *inode, struct file *filp,
2190                                         size_t size)
2191 {
2192         return 0;
2193 }
2194 
2195 #endif /* CONFIG_MANDATORY_FILE_LOCKING */
2196 
2197 
2198 #ifdef CONFIG_FILE_LOCKING
2199 static inline int break_lease(struct inode *inode, unsigned int mode)
2200 {
2201         /*
2202          * Since this check is lockless, we must ensure that any refcounts
2203          * taken are done before checking i_flctx->flc_lease. Otherwise, we
2204          * could end up racing with tasks trying to set a new lease on this
2205          * file.
2206          */
2207         smp_mb();
2208         if (inode->i_flctx && !list_empty_careful(&inode->i_flctx->flc_lease))
2209                 return __break_lease(inode, mode, FL_LEASE);
2210         return 0;
2211 }
2212 
2213 static inline int break_deleg(struct inode *inode, unsigned int mode)
2214 {
2215         /*
2216          * Since this check is lockless, we must ensure that any refcounts
2217          * taken are done before checking i_flctx->flc_lease. Otherwise, we
2218          * could end up racing with tasks trying to set a new lease on this
2219          * file.
2220          */
2221         smp_mb();
2222         if (inode->i_flctx && !list_empty_careful(&inode->i_flctx->flc_lease))
2223                 return __break_lease(inode, mode, FL_DELEG);
2224         return 0;
2225 }
2226 
2227 static inline int try_break_deleg(struct inode *inode, struct inode **delegated_inode)
2228 {
2229         int ret;
2230 
2231         ret = break_deleg(inode, O_WRONLY|O_NONBLOCK);
2232         if (ret == -EWOULDBLOCK && delegated_inode) {
2233                 *delegated_inode = inode;
2234                 ihold(inode);
2235         }
2236         return ret;
2237 }
2238 
2239 static inline int break_deleg_wait(struct inode **delegated_inode)
2240 {
2241         int ret;
2242 
2243         ret = break_deleg(*delegated_inode, O_WRONLY);
2244         iput(*delegated_inode);
2245         *delegated_inode = NULL;
2246         return ret;
2247 }
2248 
2249 static inline int break_layout(struct inode *inode, bool wait)
2250 {
2251         smp_mb();
2252         if (inode->i_flctx && !list_empty_careful(&inode->i_flctx->flc_lease))
2253                 return __break_lease(inode,
2254                                 wait ? O_WRONLY : O_WRONLY | O_NONBLOCK,
2255                                 FL_LAYOUT);
2256         return 0;
2257 }
2258 
2259 #else /* !CONFIG_FILE_LOCKING */
2260 static inline int break_lease(struct inode *inode, unsigned int mode)
2261 {
2262         return 0;
2263 }
2264 
2265 static inline int break_deleg(struct inode *inode, unsigned int mode)
2266 {
2267         return 0;
2268 }
2269 
2270 static inline int try_break_deleg(struct inode *inode, struct inode **delegated_inode)
2271 {
2272         return 0;
2273 }
2274 
2275 static inline int break_deleg_wait(struct inode **delegated_inode)
2276 {
2277         BUG();
2278         return 0;
2279 }
2280 
2281 static inline int break_layout(struct inode *inode, bool wait)
2282 {
2283         return 0;
2284 }
2285 
2286 #endif /* CONFIG_FILE_LOCKING */
2287 
2288 /* fs/open.c */
2289 struct audit_names;
2290 struct filename {
2291         const char              *name;  /* pointer to actual string */
2292         const __user char       *uptr;  /* original userland pointer */
2293         struct audit_names      *aname;
2294         int                     refcnt;
2295         const char              iname[];
2296 };
2297 
2298 extern long vfs_truncate(const struct path *, loff_t);
2299 extern int do_truncate(struct dentry *, loff_t start, unsigned int time_attrs,
2300                        struct file *filp);
2301 extern int vfs_fallocate(struct file *file, int mode, loff_t offset,
2302                         loff_t len);
2303 extern long do_sys_open(int dfd, const char __user *filename, int flags,
2304                         umode_t mode);
2305 extern struct file *file_open_name(struct filename *, int, umode_t);
2306 extern struct file *filp_open(const char *, int, umode_t);
2307 extern struct file *file_open_root(struct dentry *, struct vfsmount *,
2308                                    const char *, int, umode_t);
2309 extern struct file * dentry_open(const struct path *, int, const struct cred *);
2310 extern int filp_close(struct file *, fl_owner_t id);
2311 
2312 extern struct filename *getname_flags(const char __user *, int, int *);
2313 extern struct filename *getname(const char __user *);
2314 extern struct filename *getname_kernel(const char *);
2315 extern void putname(struct filename *name);
2316 
2317 enum {
2318         FILE_CREATED = 1,
2319         FILE_OPENED = 2
2320 };
2321 extern int finish_open(struct file *file, struct dentry *dentry,
2322                         int (*open)(struct inode *, struct file *),
2323                         int *opened);
2324 extern int finish_no_open(struct file *file, struct dentry *dentry);
2325 
2326 /* fs/ioctl.c */
2327 
2328 extern int ioctl_preallocate(struct file *filp, void __user *argp);
2329 
2330 /* fs/dcache.c */
2331 extern void __init vfs_caches_init_early(void);
2332 extern void __init vfs_caches_init(void);
2333 
2334 extern struct kmem_cache *names_cachep;
2335 
2336 #define __getname()             kmem_cache_alloc(names_cachep, GFP_KERNEL)
2337 #define __putname(name)         kmem_cache_free(names_cachep, (void *)(name))
2338 
2339 #ifdef CONFIG_BLOCK
2340 extern int register_blkdev(unsigned int, const char *);
2341 extern void unregister_blkdev(unsigned int, const char *);
2342 extern struct block_device *bdget(dev_t);
2343 extern struct block_device *bdgrab(struct block_device *bdev);
2344 extern void bd_set_size(struct block_device *, loff_t size);
2345 extern void bd_forget(struct inode *inode);
2346 extern void bdput(struct block_device *);
2347 extern void invalidate_bdev(struct block_device *);
2348 extern void iterate_bdevs(void (*)(struct block_device *, void *), void *);
2349 extern int sync_blockdev(struct block_device *bdev);
2350 extern void kill_bdev(struct block_device *);
2351 extern struct super_block *freeze_bdev(struct block_device *);
2352 extern void emergency_thaw_all(void);
2353 extern int thaw_bdev(struct block_device *bdev, struct super_block *sb);
2354 extern int fsync_bdev(struct block_device *);
2355 
2356 extern struct super_block *blockdev_superblock;
2357 
2358 static inline bool sb_is_blkdev_sb(struct super_block *sb)
2359 {
2360         return sb == blockdev_superblock;
2361 }
2362 #else
2363 static inline void bd_forget(struct inode *inode) {}
2364 static inline int sync_blockdev(struct block_device *bdev) { return 0; }
2365 static inline void kill_bdev(struct block_device *bdev) {}
2366 static inline void invalidate_bdev(struct block_device *bdev) {}
2367 
2368 static inline struct super_block *freeze_bdev(struct block_device *sb)
2369 {
2370         return NULL;
2371 }
2372 
2373 static inline int thaw_bdev(struct block_device *bdev, struct super_block *sb)
2374 {
2375         return 0;
2376 }
2377 
2378 static inline void iterate_bdevs(void (*f)(struct block_device *, void *), void *arg)
2379 {
2380 }
2381 
2382 static inline bool sb_is_blkdev_sb(struct super_block *sb)
2383 {
2384         return false;
2385 }
2386 #endif
2387 extern int sync_filesystem(struct super_block *);
2388 extern const struct file_operations def_blk_fops;
2389 extern const struct file_operations def_chr_fops;
2390 #ifdef CONFIG_BLOCK
2391 extern int ioctl_by_bdev(struct block_device *, unsigned, unsigned long);
2392 extern int blkdev_ioctl(struct block_device *, fmode_t, unsigned, unsigned long);
2393 extern long compat_blkdev_ioctl(struct file *, unsigned, unsigned long);
2394 extern int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder);
2395 extern struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
2396                                                void *holder);
2397 extern struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode,
2398                                               void *holder);
2399 extern void blkdev_put(struct block_device *bdev, fmode_t mode);
2400 extern int __blkdev_reread_part(struct block_device *bdev);
2401 extern int blkdev_reread_part(struct block_device *bdev);
2402 
2403 #ifdef CONFIG_SYSFS
2404 extern int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk);
2405 extern void bd_unlink_disk_holder(struct block_device *bdev,
2406                                   struct gendisk *disk);
2407 #else
2408 static inline int bd_link_disk_holder(struct block_device *bdev,
2409                                       struct gendisk *disk)
2410 {
2411         return 0;
2412 }
2413 static inline void bd_unlink_disk_holder(struct block_device *bdev,
2414                                          struct gendisk *disk)
2415 {
2416 }
2417 #endif
2418 #endif
2419 
2420 /* fs/char_dev.c */
2421 #define CHRDEV_MAJOR_HASH_SIZE  255
2422 /* Marks the bottom of the first segment of free char majors */
2423 #define CHRDEV_MAJOR_DYN_END 234
2424 extern int alloc_chrdev_region(dev_t *, unsigned, unsigned, const char *);
2425 extern int register_chrdev_region(dev_t, unsigned, const char *);
2426 extern int __register_chrdev(unsigned int major, unsigned int baseminor,
2427                              unsigned int count, const char *name,
2428                              const struct file_operations *fops);
2429 extern void __unregister_chrdev(unsigned int major, unsigned int baseminor,
2430                                 unsigned int count, const char *name);
2431 extern void unregister_chrdev_region(dev_t, unsigned);
2432 extern void chrdev_show(struct seq_file *,off_t);
2433 
2434 static inline int register_chrdev(unsigned int major, const char *name,
2435                                   const struct file_operations *fops)
2436 {
2437         return __register_chrdev(major, 0, 256, name, fops);
2438 }
2439 
2440 static inline void unregister_chrdev(unsigned int major, const char *name)
2441 {
2442         __unregister_chrdev(major, 0, 256, name);
2443 }
2444 
2445 /* fs/block_dev.c */
2446 #define BDEVNAME_SIZE   32      /* Largest string for a blockdev identifier */
2447 #define BDEVT_SIZE      10      /* Largest string for MAJ:MIN for blkdev */
2448 
2449 #ifdef CONFIG_BLOCK
2450 #define BLKDEV_MAJOR_HASH_SIZE  255
2451 extern const char *__bdevname(dev_t, char *buffer);
2452 extern const char *bdevname(struct block_device *bdev, char *buffer);
2453 extern struct block_device *lookup_bdev(const char *);
2454 extern void blkdev_show(struct seq_file *,off_t);
2455 
2456 #else
2457 #define BLKDEV_MAJOR_HASH_SIZE  0
2458 #endif
2459 
2460 extern void init_special_inode(struct inode *, umode_t, dev_t);
2461 
2462 /* Invalid inode operations -- fs/bad_inode.c */
2463 extern void make_bad_inode(struct inode *);
2464 extern bool is_bad_inode(struct inode *);
2465 
2466 #ifdef CONFIG_BLOCK
2467 /*
2468  * return READ, READA, or WRITE
2469  */
2470 #define bio_rw(bio)             ((bio)->bi_rw & (RW_MASK | RWA_MASK))
2471 
2472 /*
2473  * return data direction, READ or WRITE
2474  */
2475 #define bio_data_dir(bio)       ((bio)->bi_rw & 1)
2476 
2477 extern void check_disk_size_change(struct gendisk *disk,
2478                                    struct block_device *bdev);
2479 extern int revalidate_disk(struct gendisk *);
2480 extern int check_disk_change(struct block_device *);
2481 extern int __invalidate_device(struct block_device *, bool);
2482 extern int invalidate_partition(struct gendisk *, int);
2483 #endif
2484 unsigned long invalidate_mapping_pages(struct address_space *mapping,
2485                                         pgoff_t start, pgoff_t end);
2486 
2487 static inline void invalidate_remote_inode(struct inode *inode)
2488 {
2489         if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
2490             S_ISLNK(inode->i_mode))
2491                 invalidate_mapping_pages(inode->i_mapping, 0, -1);
2492 }
2493 extern int invalidate_inode_pages2(struct address_space *mapping);
2494 extern int invalidate_inode_pages2_range(struct address_space *mapping,
2495                                          pgoff_t start, pgoff_t end);
2496 extern int write_inode_now(struct inode *, int);
2497 extern int filemap_fdatawrite(struct address_space *);
2498 extern int filemap_flush(struct address_space *);
2499 extern int filemap_fdatawait(struct address_space *);
2500 extern void filemap_fdatawait_keep_errors(struct address_space *);
2501 extern int filemap_fdatawait_range(struct address_space *, loff_t lstart,
2502                                    loff_t lend);
2503 extern int filemap_write_and_wait(struct address_space *mapping);
2504 extern int filemap_write_and_wait_range(struct address_space *mapping,
2505                                         loff_t lstart, loff_t lend);
2506 extern int __filemap_fdatawrite_range(struct address_space *mapping,
2507                                 loff_t start, loff_t end, int sync_mode);
2508 extern int filemap_fdatawrite_range(struct address_space *mapping,
2509                                 loff_t start, loff_t end);
2510 
2511 extern int vfs_fsync_range(struct file *file, loff_t start, loff_t end,
2512                            int datasync);
2513 extern int vfs_fsync(struct file *file, int datasync);
2514 
2515 /*
2516  * Sync the bytes written if this was a synchronous write.  Expect ki_pos
2517  * to already be updated for the write, and will return either the amount
2518  * of bytes passed in, or an error if syncing the file failed.
2519  */
2520 static inline ssize_t generic_write_sync(struct kiocb *iocb, ssize_t count)
2521 {
2522         if (iocb->ki_flags & IOCB_DSYNC) {
2523                 int ret = vfs_fsync_range(iocb->ki_filp,
2524                                 iocb->ki_pos - count, iocb->ki_pos - 1,
2525                                 (iocb->ki_flags & IOCB_SYNC) ? 0 : 1);
2526                 if (ret)
2527                         return ret;
2528         }
2529 
2530         return count;
2531 }
2532 
2533 extern void emergency_sync(void);
2534 extern void emergency_remount(void);
2535 #ifdef CONFIG_BLOCK
2536 extern sector_t bmap(struct inode *, sector_t);
2537 #endif
2538 extern int notify_change(struct dentry *, struct iattr *, struct inode **);
2539 extern int inode_permission(struct inode *, int);
2540 extern int __inode_permission(struct inode *, int);
2541 extern int generic_permission(struct inode *, int);
2542 extern int __check_sticky(struct inode *dir, struct inode *inode);
2543 
2544 static inline bool execute_ok(struct inode *inode)
2545 {
2546         return (inode->i_mode & S_IXUGO) || S_ISDIR(inode->i_mode);
2547 }
2548 
2549 static inline void file_start_write(struct file *file)
2550 {
2551         if (!S_ISREG(file_inode(file)->i_mode))
2552                 return;
2553         __sb_start_write(file_inode(file)->i_sb, SB_FREEZE_WRITE, true);
2554 }
2555 
2556 static inline bool file_start_write_trylock(struct file *file)
2557 {
2558         if (!S_ISREG(file_inode(file)->i_mode))
2559                 return true;
2560         return __sb_start_write(file_inode(file)->i_sb, SB_FREEZE_WRITE, false);
2561 }
2562 
2563 static inline void file_end_write(struct file *file)
2564 {
2565         if (!S_ISREG(file_inode(file)->i_mode))
2566                 return;
2567         __sb_end_write(file_inode(file)->i_sb, SB_FREEZE_WRITE);
2568 }
2569 
2570 /*
2571  * get_write_access() gets write permission for a file.
2572  * put_write_access() releases this write permission.
2573  * This is used for regular files.
2574  * We cannot support write (and maybe mmap read-write shared) accesses and
2575  * MAP_DENYWRITE mmappings simultaneously. The i_writecount field of an inode
2576  * can have the following values:
2577  * 0: no writers, no VM_DENYWRITE mappings
2578  * < 0: (-i_writecount) vm_area_structs with VM_DENYWRITE set exist
2579  * > 0: (i_writecount) users are writing to the file.
2580  *
2581  * Normally we operate on that counter with atomic_{inc,dec} and it's safe
2582  * except for the cases where we don't hold i_writecount yet. Then we need to
2583  * use {get,deny}_write_access() - these functions check the sign and refuse
2584  * to do the change if sign is wrong.
2585  */
2586 static inline int get_write_access(struct inode *inode)
2587 {
2588         return atomic_inc_unless_negative(&inode->i_writecount) ? 0 : -ETXTBSY;
2589 }
2590 static inline int deny_write_access(struct file *file)
2591 {
2592         struct inode *inode = file_inode(file);
2593         return atomic_dec_unless_positive(&inode->i_writecount) ? 0 : -ETXTBSY;
2594 }
2595 static inline void put_write_access(struct inode * inode)
2596 {
2597         atomic_dec(&inode->i_writecount);
2598 }
2599 static inline void allow_write_access(struct file *file)
2600 {
2601         if (file)
2602                 atomic_inc(&file_inode(file)->i_writecount);
2603 }
2604 static inline bool inode_is_open_for_write(const struct inode *inode)
2605 {
2606         return atomic_read(&inode->i_writecount) > 0;
2607 }
2608 
2609 #ifdef CONFIG_IMA
2610 static inline void i_readcount_dec(struct inode *inode)
2611 {
2612         BUG_ON(!atomic_read(&inode->i_readcount));
2613         atomic_dec(&inode->i_readcount);
2614 }
2615 static inline void i_readcount_inc(struct inode *inode)
2616 {
2617         atomic_inc(&inode->i_readcount);
2618 }
2619 #else
2620 static inline void i_readcount_dec(struct inode *inode)
2621 {
2622         return;
2623 }
2624 static inline void i_readcount_inc(struct inode *inode)
2625 {
2626         return;
2627 }
2628 #endif
2629 extern int do_pipe_flags(int *, int);
2630 
2631 #define __kernel_read_file_id(id) \
2632         id(UNKNOWN, unknown)            \
2633         id(FIRMWARE, firmware)          \
2634         id(MODULE, kernel-module)               \
2635         id(KEXEC_IMAGE, kexec-image)            \
2636         id(KEXEC_INITRAMFS, kexec-initramfs)    \
2637         id(POLICY, security-policy)             \
2638         id(MAX_ID, )
2639 
2640 #define __fid_enumify(ENUM, dummy) READING_ ## ENUM,
2641 #define __fid_stringify(dummy, str) #str,
2642 
2643 enum kernel_read_file_id {
2644         __kernel_read_file_id(__fid_enumify)
2645 };
2646 
2647 static const char * const kernel_read_file_str[] = {
2648         __kernel_read_file_id(__fid_stringify)
2649 };
2650 
2651 static inline const char *kernel_read_file_id_str(enum kernel_read_file_id id)
2652 {
2653         if (id < 0 || id >= READING_MAX_ID)
2654                 return kernel_read_file_str[READING_UNKNOWN];
2655 
2656         return kernel_read_file_str[id];
2657 }
2658 
2659 extern int kernel_read(struct file *, loff_t, char *, unsigned long);
2660 extern int kernel_read_file(struct file *, void **, loff_t *, loff_t,
2661                             enum kernel_read_file_id);
2662 extern int kernel_read_file_from_path(char *, void **, loff_t *, loff_t,
2663                                       enum kernel_read_file_id);
2664 extern int kernel_read_file_from_fd(int, void **, loff_t *, loff_t,
2665                                     enum kernel_read_file_id);
2666 extern ssize_t kernel_write(struct file *, const char *, size_t, loff_t);
2667 extern ssize_t __kernel_write(struct file *, const char *, size_t, loff_t *);
2668 extern struct file * open_exec(const char *);
2669  
2670 /* fs/dcache.c -- generic fs support functions */
2671 extern bool is_subdir(struct dentry *, struct dentry *);
2672 extern bool path_is_under(struct path *, struct path *);
2673 
2674 extern char *file_path(struct file *, char *, int);
2675 
2676 #include <linux/err.h>
2677 
2678 /* needed for stackable file system support */
2679 extern loff_t default_llseek(struct file *file, loff_t offset, int whence);
2680 
2681 extern loff_t vfs_llseek(struct file *file, loff_t offset, int whence);
2682 
2683 extern int inode_init_always(struct super_block *, struct inode *);
2684 extern void inode_init_once(struct inode *);
2685 extern void address_space_init_once(struct address_space *mapping);
2686 extern struct inode * igrab(struct inode *);
2687 extern ino_t iunique(struct super_block *, ino_t);
2688 extern int inode_needs_sync(struct inode *inode);
2689 extern int generic_delete_inode(struct inode *inode);
2690 static inline int generic_drop_inode(struct inode *inode)
2691 {
2692         return !inode->i_nlink || inode_unhashed(inode);
2693 }
2694 
2695 extern struct inode *ilookup5_nowait(struct super_block *sb,
2696                 unsigned long hashval, int (*test)(struct inode *, void *),
2697                 void *data);
2698 extern struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
2699                 int (*test)(struct inode *, void *), void *data);
2700 extern struct inode *ilookup(struct super_block *sb, unsigned long ino);
2701 
2702 extern struct inode * iget5_locked(struct super_block *, unsigned long, int (*test)(struct inode *, void *), int (*set)(struct inode *, void *), void *);
2703 extern struct inode * iget_locked(struct super_block *, unsigned long);
2704 extern struct inode *find_inode_nowait(struct super_block *,
2705                                        unsigned long,
2706                                        int (*match)(struct inode *,
2707                                                     unsigned long, void *),
2708                                        void *data);
2709 extern int insert_inode_locked4(struct inode *, unsigned long, int (*test)(struct inode *, void *), void *);
2710 extern int insert_inode_locked(struct inode *);
2711 #ifdef CONFIG_DEBUG_LOCK_ALLOC
2712 extern void lockdep_annotate_inode_mutex_key(struct inode *inode);
2713 #else
2714 static inline void lockdep_annotate_inode_mutex_key(struct inode *inode) { };
2715 #endif
2716 extern void unlock_new_inode(struct inode *);
2717 extern unsigned int get_next_ino(void);
2718 
2719 extern void __iget(struct inode * inode);
2720 extern void iget_failed(struct inode *);
2721 extern void clear_inode(struct inode *);
2722 extern void __destroy_inode(struct inode *);
2723 extern struct inode *new_inode_pseudo(struct super_block *sb);
2724 extern struct inode *new_inode(struct super_block *sb);
2725 extern void free_inode_nonrcu(struct inode *inode);
2726 extern int should_remove_suid(struct dentry *);
2727 extern int file_remove_privs(struct file *);
2728 extern int dentry_needs_remove_privs(struct dentry *dentry);
2729 static inline int file_needs_remove_privs(struct file *file)
2730 {
2731         return dentry_needs_remove_privs(file->f_path.dentry);
2732 }
2733 
2734 extern void __insert_inode_hash(struct inode *, unsigned long hashval);
2735 static inline void insert_inode_hash(struct inode *inode)
2736 {
2737         __insert_inode_hash(inode, inode->i_ino);
2738 }
2739 
2740 extern void __remove_inode_hash(struct inode *);
2741 static inline void remove_inode_hash(struct inode *inode)
2742 {
2743         if (!inode_unhashed(inode) && !hlist_fake(&inode->i_hash))
2744                 __remove_inode_hash(inode);
2745 }
2746 
2747 extern void inode_sb_list_add(struct inode *inode);
2748 
2749 #ifdef CONFIG_BLOCK
2750 extern blk_qc_t submit_bio(int, struct bio *);
2751 extern int bdev_read_only(struct block_device *);
2752 #endif
2753 extern int set_blocksize(struct block_device *, int);
2754 extern int sb_set_blocksize(struct super_block *, int);
2755 extern int sb_min_blocksize(struct super_block *, int);
2756 
2757 extern int generic_file_mmap(struct file *, struct vm_area_struct *);
2758 extern int generic_file_readonly_mmap(struct file *, struct vm_area_struct *);
2759 extern ssize_t generic_write_checks(struct kiocb *, struct iov_iter *);
2760 extern ssize_t generic_file_read_iter(struct kiocb *, struct iov_iter *);
2761 extern ssize_t __generic_file_write_iter(struct kiocb *, struct iov_iter *);
2762 extern ssize_t generic_file_write_iter(struct kiocb *, struct iov_iter *);
2763 extern ssize_t generic_file_direct_write(struct kiocb *, struct iov_iter *);
2764 extern ssize_t generic_perform_write(struct file *, struct iov_iter *, loff_t);
2765 
2766 ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos);
2767 ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos);
2768 
2769 /* fs/block_dev.c */
2770 extern ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to);
2771 extern ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from);
2772 extern int blkdev_fsync(struct file *filp, loff_t start, loff_t end,
2773                         int datasync);
2774 extern void block_sync_page(struct page *page);
2775 
2776 /* fs/splice.c */
2777 extern ssize_t generic_file_splice_read(struct file *, loff_t *,
2778                 struct pipe_inode_info *, size_t, unsigned int);
2779 extern ssize_t default_file_splice_read(struct file *, loff_t *,
2780                 struct pipe_inode_info *, size_t, unsigned int);
2781 extern ssize_t iter_file_splice_write(struct pipe_inode_info *,
2782                 struct file *, loff_t *, size_t, unsigned int);
2783 extern ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe,
2784                 struct file *out, loff_t *, size_t len, unsigned int flags);
2785 extern long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
2786                 loff_t *opos, size_t len, unsigned int flags);
2787 
2788 
2789 extern void
2790 file_ra_state_init(struct file_ra_state *ra, struct address_space *mapping);
2791 extern loff_t noop_llseek(struct file *file, loff_t offset, int whence);
2792 extern loff_t no_llseek(struct file *file, loff_t offset, int whence);
2793 extern loff_t vfs_setpos(struct file *file, loff_t offset, loff_t maxsize);
2794 extern loff_t generic_file_llseek(struct file *file, loff_t offset, int whence);
2795 extern loff_t generic_file_llseek_size(struct file *file, loff_t offset,
2796                 int whence, loff_t maxsize, loff_t eof);
2797 extern loff_t fixed_size_llseek(struct file *file, loff_t offset,
2798                 int whence, loff_t size);
2799 extern loff_t no_seek_end_llseek_size(struct file *, loff_t, int, loff_t);
2800 extern loff_t no_seek_end_llseek(struct file *, loff_t, int);
2801 extern int generic_file_open(struct inode * inode, struct file * filp);
2802 extern int nonseekable_open(struct inode * inode, struct file * filp);
2803 
2804 #ifdef CONFIG_BLOCK
2805 typedef void (dio_submit_t)(int rw, struct bio *bio, struct inode *inode,
2806                             loff_t file_offset);
2807 
2808 enum {
2809         /* need locking between buffered and direct access */
2810         DIO_LOCKING     = 0x01,
2811 
2812         /* filesystem does not support filling holes */
2813         DIO_SKIP_HOLES  = 0x02,
2814 
2815         /* filesystem can handle aio writes beyond i_size */
2816         DIO_ASYNC_EXTEND = 0x04,
2817 
2818         /* inode/fs/bdev does not need truncate protection */
2819         DIO_SKIP_DIO_COUNT = 0x08,
2820 };
2821 
2822 void dio_end_io(struct bio *bio, int error);
2823 
2824 ssize_t __blockdev_direct_IO(struct kiocb *iocb, struct inode *inode,
2825                              struct block_device *bdev, struct iov_iter *iter,
2826                              get_block_t get_block,
2827                              dio_iodone_t end_io, dio_submit_t submit_io,
2828                              int flags);
2829 
2830 static inline ssize_t blockdev_direct_IO(struct kiocb *iocb,
2831                                          struct inode *inode,
2832                                          struct iov_iter *iter,
2833                                          get_block_t get_block)
2834 {
2835         return __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev, iter,
2836                         get_block, NULL, NULL, DIO_LOCKING | DIO_SKIP_HOLES);
2837 }
2838 #endif
2839 
2840 void inode_dio_wait(struct inode *inode);
2841 
2842 /*
2843  * inode_dio_begin - signal start of a direct I/O requests
2844  * @inode: inode the direct I/O happens on
2845  *
2846  * This is called once we've finished processing a direct I/O request,
2847  * and is used to wake up callers waiting for direct I/O to be quiesced.
2848  */
2849 static inline void inode_dio_begin(struct inode *inode)
2850 {
2851         atomic_inc(&inode->i_dio_count);
2852 }
2853 
2854 /*
2855  * inode_dio_end - signal finish of a direct I/O requests
2856  * @inode: inode the direct I/O happens on
2857  *
2858  * This is called once we've finished processing a direct I/O request,
2859  * and is used to wake up callers waiting for direct I/O to be quiesced.
2860  */
2861 static inline void inode_dio_end(struct inode *inode)
2862 {
2863         if (atomic_dec_and_test(&inode->i_dio_count))
2864                 wake_up_bit(&inode->i_state, __I_DIO_WAKEUP);
2865 }
2866 
2867 extern void inode_set_flags(struct inode *inode, unsigned int flags,
2868                             unsigned int mask);
2869 
2870 extern const struct file_operations generic_ro_fops;
2871 
2872 #define special_file(m) (S_ISCHR(m)||S_ISBLK(m)||S_ISFIFO(m)||S_ISSOCK(m))
2873 
2874 extern int readlink_copy(char __user *, int, const char *);
2875 extern int page_readlink(struct dentry *, char __user *, int);
2876 extern const char *page_get_link(struct dentry *, struct inode *,
2877                                  struct delayed_call *);
2878 extern void page_put_link(void *);
2879 extern int __page_symlink(struct inode *inode, const char *symname, int len,
2880                 int nofs);
2881 extern int page_symlink(struct inode *inode, const char *symname, int len);
2882 extern const struct inode_operations page_symlink_inode_operations;
2883 extern void kfree_link(void *);
2884 extern int generic_readlink(struct dentry *, char __user *, int);
2885 extern void generic_fillattr(struct inode *, struct kstat *);
2886 int vfs_getattr_nosec(struct path *path, struct kstat *stat);
2887 extern int vfs_getattr(struct path *, struct kstat *);
2888 void __inode_add_bytes(struct inode *inode, loff_t bytes);
2889 void inode_add_bytes(struct inode *inode, loff_t bytes);
2890 void __inode_sub_bytes(struct inode *inode, loff_t bytes);
2891 void inode_sub_bytes(struct inode *inode, loff_t bytes);
2892 loff_t inode_get_bytes(struct inode *inode);
2893 void inode_set_bytes(struct inode *inode, loff_t bytes);
2894 const char *simple_get_link(struct dentry *, struct inode *,
2895                             struct delayed_call *);
2896 extern const struct inode_operations simple_symlink_inode_operations;
2897 
2898 extern int iterate_dir(struct file *, struct dir_context *);
2899 
2900 extern int vfs_stat(const char __user *, struct kstat *);
2901 extern int vfs_lstat(const char __user *, struct kstat *);
2902 extern int vfs_fstat(unsigned int, struct kstat *);
2903 extern int vfs_fstatat(int , const char __user *, struct kstat *, int);
2904 
2905 extern int __generic_block_fiemap(struct inode *inode,
2906                                   struct fiemap_extent_info *fieinfo,
2907                                   loff_t start, loff_t len,
2908                                   get_block_t *get_block);
2909 extern int generic_block_fiemap(struct inode *inode,
2910                                 struct fiemap_extent_info *fieinfo, u64 start,
2911                                 u64 len, get_block_t *get_block);
2912 
2913 extern void get_filesystem(struct file_system_type *fs);
2914 extern void put_filesystem(struct file_system_type *fs);
2915 extern struct file_system_type *get_fs_type(const char *name);
2916 extern struct super_block *get_super(struct block_device *);
2917 extern struct super_block *get_super_thawed(struct block_device *);
2918 extern struct super_block *get_active_super(struct block_device *bdev);
2919 extern void drop_super(struct super_block *sb);
2920 extern void iterate_supers(void (*)(struct super_block *, void *), void *);
2921 extern void iterate_supers_type(struct file_system_type *,
2922                                 void (*)(struct super_block *, void *), void *);
2923 
2924 extern int dcache_dir_open(struct inode *, struct file *);
2925 extern int dcache_dir_close(struct inode *, struct file *);
2926 extern loff_t dcache_dir_lseek(struct file *, loff_t, int);
2927 extern int dcache_readdir(struct file *, struct dir_context *);
2928 extern int simple_setattr(struct dentry *, struct iattr *);
2929 extern int simple_getattr(struct vfsmount *, struct dentry *, struct kstat *);
2930 extern int simple_statfs(struct dentry *, struct kstatfs *);
2931 extern int simple_open(struct inode *inode, struct file *file);
2932 extern int simple_link(struct dentry *, struct inode *, struct dentry *);
2933 extern int simple_unlink(struct inode *, struct dentry *);
2934 extern int simple_rmdir(struct inode *, struct dentry *);
2935 extern int simple_rename(struct inode *, struct dentry *, struct inode *, struct dentry *);
2936 extern int noop_fsync(struct file *, loff_t, loff_t, int);
2937 extern int simple_empty(struct dentry *);
2938 extern int simple_readpage(struct file *file, struct page *page);
2939 extern int simple_write_begin(struct file *file, struct address_space *mapping,
2940                         loff_t pos, unsigned len, unsigned flags,
2941                         struct page **pagep, void **fsdata);
2942 extern int simple_write_end(struct file *file, struct address_space *mapping,
2943                         loff_t pos, unsigned len, unsigned copied,
2944                         struct page *page, void *fsdata);
2945 extern int always_delete_dentry(const struct dentry *);
2946 extern struct inode *alloc_anon_inode(struct super_block *);
2947 extern int simple_nosetlease(struct file *, long, struct file_lock **, void **);
2948 extern const struct dentry_operations simple_dentry_operations;
2949 
2950 extern struct dentry *simple_lookup(struct inode *, struct dentry *, unsigned int flags);
2951 extern ssize_t generic_read_dir(struct file *, char __user *, size_t, loff_t *);
2952 extern const struct file_operations simple_dir_operations;
2953 extern const struct inode_operations simple_dir_inode_operations;
2954 extern void make_empty_dir_inode(struct inode *inode);
2955 extern bool is_empty_dir_inode(struct inode *inode);
2956 struct tree_descr { char *name; const struct file_operations *ops; int mode; };
2957 struct dentry *d_alloc_name(struct dentry *, const char *);
2958 extern int simple_fill_super(struct super_block *, unsigned long, struct tree_descr *);
2959 extern int simple_pin_fs(struct file_system_type *, struct vfsmount **mount, int *count);
2960 extern void simple_release_fs(struct vfsmount **mount, int *count);
2961 
2962 extern ssize_t simple_read_from_buffer(void __user *to, size_t count,
2963                         loff_t *ppos, const void *from, size_t available);
2964 extern ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos,
2965                 const void __user *from, size_t count);
2966 
2967 extern int __generic_file_fsync(struct file *, loff_t, loff_t, int);
2968 extern int generic_file_fsync(struct file *, loff_t, loff_t, int);
2969 
2970 extern int generic_check_addressable(unsigned, u64);
2971 
2972 #ifdef CONFIG_MIGRATION
2973 extern int buffer_migrate_page(struct address_space *,
2974                                 struct page *, struct page *,
2975                                 enum migrate_mode);
2976 #else
2977 #define buffer_migrate_page NULL
2978 #endif
2979 
2980 extern int inode_change_ok(const struct inode *, struct iattr *);
2981 extern int inode_newsize_ok(const struct inode *, loff_t offset);
2982 extern void setattr_copy(struct inode *inode, const struct iattr *attr);
2983 
2984 extern int file_update_time(struct file *file);
2985 
2986 extern int generic_show_options(struct seq_file *m, struct dentry *root);
2987 extern void save_mount_options(struct super_block *sb, char *options);
2988 extern void replace_mount_options(struct super_block *sb, char *options);
2989 
2990 static inline bool io_is_direct(struct file *filp)
2991 {
2992         return (filp->f_flags & O_DIRECT) || IS_DAX(filp->f_mapping->host);
2993 }
2994 
2995 static inline int iocb_flags(struct file *file)
2996 {
2997         int res = 0;
2998         if (file->f_flags & O_APPEND)
2999                 res |= IOCB_APPEND;
3000         if (io_is_direct(file))
3001                 res |= IOCB_DIRECT;
3002         if ((file->f_flags & O_DSYNC) || IS_SYNC(file->f_mapping->host))
3003                 res |= IOCB_DSYNC;
3004         if (file->f_flags & __O_SYNC)
3005                 res |= IOCB_SYNC;
3006         return res;
3007 }
3008 
3009 static inline ino_t parent_ino(struct dentry *dentry)
3010 {
3011         ino_t res;
3012 
3013         /*
3014          * Don't strictly need d_lock here? If the parent ino could change
3015          * then surely we'd have a deeper race in the caller?
3016          */
3017         spin_lock(&dentry->d_lock);
3018         res = dentry->d_parent->d_inode->i_ino;
3019         spin_unlock(&dentry->d_lock);
3020         return res;
3021 }
3022 
3023 /* Transaction based IO helpers */
3024 
3025 /*
3026  * An argresp is stored in an allocated page and holds the
3027  * size of the argument or response, along with its content
3028  */
3029 struct simple_transaction_argresp {
3030         ssize_t size;
3031         char data[0];
3032 };
3033 
3034 #define SIMPLE_TRANSACTION_LIMIT (PAGE_SIZE - sizeof(struct simple_transaction_argresp))
3035 
3036 char *simple_transaction_get(struct file *file, const char __user *buf,
3037                                 size_t size);
3038 ssize_t simple_transaction_read(struct file *file, char __user *buf,
3039                                 size_t size, loff_t *pos);
3040 int simple_transaction_release(struct inode *inode, struct file *file);
3041 
3042 void simple_transaction_set(struct file *file, size_t n);
3043 
3044 /*
3045  * simple attribute files
3046  *
3047  * These attributes behave similar to those in sysfs:
3048  *
3049  * Writing to an attribute immediately sets a value, an open file can be
3050  * written to multiple times.
3051  *
3052  * Reading from an attribute creates a buffer from the value that might get
3053  * read with multiple read calls. When the attribute has been read
3054  * completely, no further read calls are possible until the file is opened
3055  * again.
3056  *
3057  * All attributes contain a text representation of a numeric value
3058  * that are accessed with the get() and set() functions.
3059  */
3060 #define DEFINE_SIMPLE_ATTRIBUTE(__fops, __get, __set, __fmt)            \
3061 static int __fops ## _open(struct inode *inode, struct file *file)      \
3062 {                                                                       \
3063         __simple_attr_check_format(__fmt, 0ull);                        \
3064         return simple_attr_open(inode, file, __get, __set, __fmt);      \
3065 }                                                                       \
3066 static const struct file_operations __fops = {                          \
3067         .owner   = THIS_MODULE,                                         \
3068         .open    = __fops ## _open,                                     \
3069         .release = simple_attr_release,                                 \
3070         .read    = simple_attr_read,                                    \
3071         .write   = simple_attr_write,                                   \
3072         .llseek  = generic_file_llseek,                                 \
3073 }
3074 
3075 static inline __printf(1, 2)
3076 void __simple_attr_check_format(const char *fmt, ...)
3077 {
3078         /* don't do anything, just let the compiler check the arguments; */
3079 }
3080 
3081 int simple_attr_open(struct inode *inode, struct file *file,
3082                      int (*get)(void *, u64 *), int (*set)(void *, u64),
3083                      const char *fmt);
3084 int simple_attr_release(struct inode *inode, struct file *file);
3085 ssize_t simple_attr_read(struct file *file, char __user *buf,
3086                          size_t len, loff_t *ppos);
3087 ssize_t simple_attr_write(struct file *file, const char __user *buf,
3088                           size_t len, loff_t *ppos);
3089 
3090 struct ctl_table;
3091 int proc_nr_files(struct ctl_table *table, int write,
3092                   void __user *buffer, size_t *lenp, loff_t *ppos);
3093 int proc_nr_dentry(struct ctl_table *table, int write,
3094                   void __user *buffer, size_t *lenp, loff_t *ppos);
3095 int proc_nr_inodes(struct ctl_table *table, int write,
3096                    void __user *buffer, size_t *lenp, loff_t *ppos);
3097 int __init get_filesystem_list(char *buf);
3098 
3099 #define __FMODE_EXEC            ((__force int) FMODE_EXEC)
3100 #define __FMODE_NONOTIFY        ((__force int) FMODE_NONOTIFY)
3101 
3102 #define ACC_MODE(x) ("\004\002\006\006"[(x)&O_ACCMODE])
3103 #define OPEN_FMODE(flag) ((__force fmode_t)(((flag + 1) & O_ACCMODE) | \
3104                                             (flag & __FMODE_NONOTIFY)))
3105 
3106 static inline bool is_sxid(umode_t mode)
3107 {
3108         return (mode & S_ISUID) || ((mode & S_ISGID) && (mode & S_IXGRP));
3109 }
3110 
3111 static inline int check_sticky(struct inode *dir, struct inode *inode)
3112 {
3113         if (!(dir->i_mode & S_ISVTX))
3114                 return 0;
3115 
3116         return __check_sticky(dir, inode);
3117 }
3118 
3119 static inline void inode_has_no_xattr(struct inode *inode)
3120 {
3121         if (!is_sxid(inode->i_mode) && (inode->i_sb->s_flags & MS_NOSEC))
3122                 inode->i_flags |= S_NOSEC;
3123 }
3124 
3125 static inline bool is_root_inode(struct inode *inode)
3126 {
3127         return inode == inode->i_sb->s_root->d_inode;
3128 }
3129 
3130 static inline bool dir_emit(struct dir_context *ctx,
3131                             const char *name, int namelen,
3132                             u64 ino, unsigned type)
3133 {
3134         return ctx->actor(ctx, name, namelen, ctx->pos, ino, type) == 0;
3135 }
3136 static inline bool dir_emit_dot(struct file *file, struct dir_context *ctx)
3137 {
3138         return ctx->actor(ctx, ".", 1, ctx->pos,
3139                           file->f_path.dentry->d_inode->i_ino, DT_DIR) == 0;
3140 }
3141 static inline bool dir_emit_dotdot(struct file *file, struct dir_context *ctx)
3142 {
3143         return ctx->actor(ctx, "..", 2, ctx->pos,
3144                           parent_ino(file->f_path.dentry), DT_DIR) == 0;
3145 }
3146 static inline bool dir_emit_dots(struct file *file, struct dir_context *ctx)
3147 {
3148         if (ctx->pos == 0) {
3149                 if (!dir_emit_dot(file, ctx))
3150                         return false;
3151                 ctx->pos = 1;
3152         }
3153         if (ctx->pos == 1) {
3154                 if (!dir_emit_dotdot(file, ctx))
3155                         return false;
3156                 ctx->pos = 2;
3157         }
3158         return true;
3159 }
3160 static inline bool dir_relax(struct inode *inode)
3161 {
3162         inode_unlock(inode);
3163         inode_lock(inode);
3164         return !IS_DEADDIR(inode);
3165 }
3166 
3167 static inline bool dir_relax_shared(struct inode *inode)
3168 {
3169         inode_unlock_shared(inode);
3170         inode_lock_shared(inode);
3171         return !IS_DEADDIR(inode);
3172 }
3173 
3174 extern bool path_noexec(const struct path *path);
3175 extern void inode_nohighmem(struct inode *inode);
3176 
3177 #endif /* _LINUX_FS_H */
3178 

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