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

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  1 /* SPDX-License-Identifier: GPL-2.0 */
  2 #ifndef _LINUX_FS_H
  3 #define _LINUX_FS_H
  4 
  5 #include <linux/linkage.h>
  6 #include <linux/wait_bit.h>
  7 #include <linux/kdev_t.h>
  8 #include <linux/dcache.h>
  9 #include <linux/path.h>
 10 #include <linux/stat.h>
 11 #include <linux/cache.h>
 12 #include <linux/list.h>
 13 #include <linux/list_lru.h>
 14 #include <linux/llist.h>
 15 #include <linux/radix-tree.h>
 16 #include <linux/rbtree.h>
 17 #include <linux/init.h>
 18 #include <linux/pid.h>
 19 #include <linux/bug.h>
 20 #include <linux/mutex.h>
 21 #include <linux/rwsem.h>
 22 #include <linux/mm_types.h>
 23 #include <linux/capability.h>
 24 #include <linux/semaphore.h>
 25 #include <linux/fcntl.h>
 26 #include <linux/fiemap.h>
 27 #include <linux/rculist_bl.h>
 28 #include <linux/atomic.h>
 29 #include <linux/shrinker.h>
 30 #include <linux/migrate_mode.h>
 31 #include <linux/uidgid.h>
 32 #include <linux/lockdep.h>
 33 #include <linux/percpu-rwsem.h>
 34 #include <linux/workqueue.h>
 35 #include <linux/delayed_call.h>
 36 #include <linux/uuid.h>
 37 #include <linux/errseq.h>
 38 
 39 #include <asm/byteorder.h>
 40 #include <uapi/linux/fs.h>
 41 
 42 struct backing_dev_info;
 43 struct bdi_writeback;
 44 struct bio;
 45 struct export_operations;
 46 struct hd_geometry;
 47 struct iovec;
 48 struct kiocb;
 49 struct kobject;
 50 struct pipe_inode_info;
 51 struct poll_table_struct;
 52 struct kstatfs;
 53 struct vm_area_struct;
 54 struct vfsmount;
 55 struct cred;
 56 struct swap_info_struct;
 57 struct seq_file;
 58 struct workqueue_struct;
 59 struct iov_iter;
 60 struct fscrypt_info;
 61 struct fscrypt_operations;
 62 
 63 extern void __init inode_init(void);
 64 extern void __init inode_init_early(void);
 65 extern void __init files_init(void);
 66 extern void __init files_maxfiles_init(void);
 67 
 68 extern struct files_stat_struct files_stat;
 69 extern unsigned long get_max_files(void);
 70 extern unsigned int sysctl_nr_open;
 71 extern struct inodes_stat_t inodes_stat;
 72 extern int leases_enable, lease_break_time;
 73 extern int sysctl_protected_symlinks;
 74 extern int sysctl_protected_hardlinks;
 75 
 76 typedef __kernel_rwf_t rwf_t;
 77 
 78 struct buffer_head;
 79 typedef int (get_block_t)(struct inode *inode, sector_t iblock,
 80                         struct buffer_head *bh_result, int create);
 81 typedef int (dio_iodone_t)(struct kiocb *iocb, loff_t offset,
 82                         ssize_t bytes, void *private);
 83 
 84 #define MAY_EXEC                0x00000001
 85 #define MAY_WRITE               0x00000002
 86 #define MAY_READ                0x00000004
 87 #define MAY_APPEND              0x00000008
 88 #define MAY_ACCESS              0x00000010
 89 #define MAY_OPEN                0x00000020
 90 #define MAY_CHDIR               0x00000040
 91 /* called from RCU mode, don't block */
 92 #define MAY_NOT_BLOCK           0x00000080
 93 
 94 /*
 95  * flags in file.f_mode.  Note that FMODE_READ and FMODE_WRITE must correspond
 96  * to O_WRONLY and O_RDWR via the strange trick in __dentry_open()
 97  */
 98 
 99 /* file is open for reading */
100 #define FMODE_READ              ((__force fmode_t)0x1)
101 /* file is open for writing */
102 #define FMODE_WRITE             ((__force fmode_t)0x2)
103 /* file is seekable */
104 #define FMODE_LSEEK             ((__force fmode_t)0x4)
105 /* file can be accessed using pread */
106 #define FMODE_PREAD             ((__force fmode_t)0x8)
107 /* file can be accessed using pwrite */
108 #define FMODE_PWRITE            ((__force fmode_t)0x10)
109 /* File is opened for execution with sys_execve / sys_uselib */
110 #define FMODE_EXEC              ((__force fmode_t)0x20)
111 /* File is opened with O_NDELAY (only set for block devices) */
112 #define FMODE_NDELAY            ((__force fmode_t)0x40)
113 /* File is opened with O_EXCL (only set for block devices) */
114 #define FMODE_EXCL              ((__force fmode_t)0x80)
115 /* File is opened using open(.., 3, ..) and is writeable only for ioctls
116    (specialy hack for floppy.c) */
117 #define FMODE_WRITE_IOCTL       ((__force fmode_t)0x100)
118 /* 32bit hashes as llseek() offset (for directories) */
119 #define FMODE_32BITHASH         ((__force fmode_t)0x200)
120 /* 64bit hashes as llseek() offset (for directories) */
121 #define FMODE_64BITHASH         ((__force fmode_t)0x400)
122 
123 /*
124  * Don't update ctime and mtime.
125  *
126  * Currently a special hack for the XFS open_by_handle ioctl, but we'll
127  * hopefully graduate it to a proper O_CMTIME flag supported by open(2) soon.
128  */
129 #define FMODE_NOCMTIME          ((__force fmode_t)0x800)
130 
131 /* Expect random access pattern */
132 #define FMODE_RANDOM            ((__force fmode_t)0x1000)
133 
134 /* File is huge (eg. /dev/kmem): treat loff_t as unsigned */
135 #define FMODE_UNSIGNED_OFFSET   ((__force fmode_t)0x2000)
136 
137 /* File is opened with O_PATH; almost nothing can be done with it */
138 #define FMODE_PATH              ((__force fmode_t)0x4000)
139 
140 /* File needs atomic accesses to f_pos */
141 #define FMODE_ATOMIC_POS        ((__force fmode_t)0x8000)
142 /* Write access to underlying fs */
143 #define FMODE_WRITER            ((__force fmode_t)0x10000)
144 /* Has read method(s) */
145 #define FMODE_CAN_READ          ((__force fmode_t)0x20000)
146 /* Has write method(s) */
147 #define FMODE_CAN_WRITE         ((__force fmode_t)0x40000)
148 
149 /* File was opened by fanotify and shouldn't generate fanotify events */
150 #define FMODE_NONOTIFY          ((__force fmode_t)0x4000000)
151 
152 /* File is capable of returning -EAGAIN if I/O will block */
153 #define FMODE_NOWAIT    ((__force fmode_t)0x8000000)
154 
155 /*
156  * Flag for rw_copy_check_uvector and compat_rw_copy_check_uvector
157  * that indicates that they should check the contents of the iovec are
158  * valid, but not check the memory that the iovec elements
159  * points too.
160  */
161 #define CHECK_IOVEC_ONLY -1
162 
163 /*
164  * Attribute flags.  These should be or-ed together to figure out what
165  * has been changed!
166  */
167 #define ATTR_MODE       (1 << 0)
168 #define ATTR_UID        (1 << 1)
169 #define ATTR_GID        (1 << 2)
170 #define ATTR_SIZE       (1 << 3)
171 #define ATTR_ATIME      (1 << 4)
172 #define ATTR_MTIME      (1 << 5)
173 #define ATTR_CTIME      (1 << 6)
174 #define ATTR_ATIME_SET  (1 << 7)
175 #define ATTR_MTIME_SET  (1 << 8)
176 #define ATTR_FORCE      (1 << 9) /* Not a change, but a change it */
177 #define ATTR_ATTR_FLAG  (1 << 10)
178 #define ATTR_KILL_SUID  (1 << 11)
179 #define ATTR_KILL_SGID  (1 << 12)
180 #define ATTR_FILE       (1 << 13)
181 #define ATTR_KILL_PRIV  (1 << 14)
182 #define ATTR_OPEN       (1 << 15) /* Truncating from open(O_TRUNC) */
183 #define ATTR_TIMES_SET  (1 << 16)
184 #define ATTR_TOUCH      (1 << 17)
185 
186 /*
187  * Whiteout is represented by a char device.  The following constants define the
188  * mode and device number to use.
189  */
190 #define WHITEOUT_MODE 0
191 #define WHITEOUT_DEV 0
192 
193 /*
194  * This is the Inode Attributes structure, used for notify_change().  It
195  * uses the above definitions as flags, to know which values have changed.
196  * Also, in this manner, a Filesystem can look at only the values it cares
197  * about.  Basically, these are the attributes that the VFS layer can
198  * request to change from the FS layer.
199  *
200  * Derek Atkins <warlord@MIT.EDU> 94-10-20
201  */
202 struct iattr {
203         unsigned int    ia_valid;
204         umode_t         ia_mode;
205         kuid_t          ia_uid;
206         kgid_t          ia_gid;
207         loff_t          ia_size;
208         struct timespec ia_atime;
209         struct timespec ia_mtime;
210         struct timespec ia_ctime;
211 
212         /*
213          * Not an attribute, but an auxiliary info for filesystems wanting to
214          * implement an ftruncate() like method.  NOTE: filesystem should
215          * check for (ia_valid & ATTR_FILE), and not for (ia_file != NULL).
216          */
217         struct file     *ia_file;
218 };
219 
220 /*
221  * Includes for diskquotas.
222  */
223 #include <linux/quota.h>
224 
225 /*
226  * Maximum number of layers of fs stack.  Needs to be limited to
227  * prevent kernel stack overflow
228  */
229 #define FILESYSTEM_MAX_STACK_DEPTH 2
230 
231 /** 
232  * enum positive_aop_returns - aop return codes with specific semantics
233  *
234  * @AOP_WRITEPAGE_ACTIVATE: Informs the caller that page writeback has
235  *                          completed, that the page is still locked, and
236  *                          should be considered active.  The VM uses this hint
237  *                          to return the page to the active list -- it won't
238  *                          be a candidate for writeback again in the near
239  *                          future.  Other callers must be careful to unlock
240  *                          the page if they get this return.  Returned by
241  *                          writepage(); 
242  *
243  * @AOP_TRUNCATED_PAGE: The AOP method that was handed a locked page has
244  *                      unlocked it and the page might have been truncated.
245  *                      The caller should back up to acquiring a new page and
246  *                      trying again.  The aop will be taking reasonable
247  *                      precautions not to livelock.  If the caller held a page
248  *                      reference, it should drop it before retrying.  Returned
249  *                      by readpage().
250  *
251  * address_space_operation functions return these large constants to indicate
252  * special semantics to the caller.  These are much larger than the bytes in a
253  * page to allow for functions that return the number of bytes operated on in a
254  * given page.
255  */
256 
257 enum positive_aop_returns {
258         AOP_WRITEPAGE_ACTIVATE  = 0x80000,
259         AOP_TRUNCATED_PAGE      = 0x80001,
260 };
261 
262 #define AOP_FLAG_CONT_EXPAND            0x0001 /* called from cont_expand */
263 #define AOP_FLAG_NOFS                   0x0002 /* used by filesystem to direct
264                                                 * helper code (eg buffer layer)
265                                                 * to clear GFP_FS from alloc */
266 
267 /*
268  * oh the beauties of C type declarations.
269  */
270 struct page;
271 struct address_space;
272 struct writeback_control;
273 
274 /*
275  * Write life time hint values.
276  */
277 enum rw_hint {
278         WRITE_LIFE_NOT_SET      = 0,
279         WRITE_LIFE_NONE         = RWH_WRITE_LIFE_NONE,
280         WRITE_LIFE_SHORT        = RWH_WRITE_LIFE_SHORT,
281         WRITE_LIFE_MEDIUM       = RWH_WRITE_LIFE_MEDIUM,
282         WRITE_LIFE_LONG         = RWH_WRITE_LIFE_LONG,
283         WRITE_LIFE_EXTREME      = RWH_WRITE_LIFE_EXTREME,
284 };
285 
286 #define IOCB_EVENTFD            (1 << 0)
287 #define IOCB_APPEND             (1 << 1)
288 #define IOCB_DIRECT             (1 << 2)
289 #define IOCB_HIPRI              (1 << 3)
290 #define IOCB_DSYNC              (1 << 4)
291 #define IOCB_SYNC               (1 << 5)
292 #define IOCB_WRITE              (1 << 6)
293 #define IOCB_NOWAIT             (1 << 7)
294 
295 struct kiocb {
296         struct file             *ki_filp;
297         loff_t                  ki_pos;
298         void (*ki_complete)(struct kiocb *iocb, long ret, long ret2);
299         void                    *private;
300         int                     ki_flags;
301         enum rw_hint            ki_hint;
302 } __randomize_layout;
303 
304 static inline bool is_sync_kiocb(struct kiocb *kiocb)
305 {
306         return kiocb->ki_complete == NULL;
307 }
308 
309 /*
310  * "descriptor" for what we're up to with a read.
311  * This allows us to use the same read code yet
312  * have multiple different users of the data that
313  * we read from a file.
314  *
315  * The simplest case just copies the data to user
316  * mode.
317  */
318 typedef struct {
319         size_t written;
320         size_t count;
321         union {
322                 char __user *buf;
323                 void *data;
324         } arg;
325         int error;
326 } read_descriptor_t;
327 
328 typedef int (*read_actor_t)(read_descriptor_t *, struct page *,
329                 unsigned long, unsigned long);
330 
331 struct address_space_operations {
332         int (*writepage)(struct page *page, struct writeback_control *wbc);
333         int (*readpage)(struct file *, struct page *);
334 
335         /* Write back some dirty pages from this mapping. */
336         int (*writepages)(struct address_space *, struct writeback_control *);
337 
338         /* Set a page dirty.  Return true if this dirtied it */
339         int (*set_page_dirty)(struct page *page);
340 
341         int (*readpages)(struct file *filp, struct address_space *mapping,
342                         struct list_head *pages, unsigned nr_pages);
343 
344         int (*write_begin)(struct file *, struct address_space *mapping,
345                                 loff_t pos, unsigned len, unsigned flags,
346                                 struct page **pagep, void **fsdata);
347         int (*write_end)(struct file *, struct address_space *mapping,
348                                 loff_t pos, unsigned len, unsigned copied,
349                                 struct page *page, void *fsdata);
350 
351         /* Unfortunately this kludge is needed for FIBMAP. Don't use it */
352         sector_t (*bmap)(struct address_space *, sector_t);
353         void (*invalidatepage) (struct page *, unsigned int, unsigned int);
354         int (*releasepage) (struct page *, gfp_t);
355         void (*freepage)(struct page *);
356         ssize_t (*direct_IO)(struct kiocb *, struct iov_iter *iter);
357         /*
358          * migrate the contents of a page to the specified target. If
359          * migrate_mode is MIGRATE_ASYNC, it must not block.
360          */
361         int (*migratepage) (struct address_space *,
362                         struct page *, struct page *, enum migrate_mode);
363         bool (*isolate_page)(struct page *, isolate_mode_t);
364         void (*putback_page)(struct page *);
365         int (*launder_page) (struct page *);
366         int (*is_partially_uptodate) (struct page *, unsigned long,
367                                         unsigned long);
368         void (*is_dirty_writeback) (struct page *, bool *, bool *);
369         int (*error_remove_page)(struct address_space *, struct page *);
370 
371         /* swapfile support */
372         int (*swap_activate)(struct swap_info_struct *sis, struct file *file,
373                                 sector_t *span);
374         void (*swap_deactivate)(struct file *file);
375 };
376 
377 extern const struct address_space_operations empty_aops;
378 
379 /*
380  * pagecache_write_begin/pagecache_write_end must be used by general code
381  * to write into the pagecache.
382  */
383 int pagecache_write_begin(struct file *, struct address_space *mapping,
384                                 loff_t pos, unsigned len, unsigned flags,
385                                 struct page **pagep, void **fsdata);
386 
387 int pagecache_write_end(struct file *, struct address_space *mapping,
388                                 loff_t pos, unsigned len, unsigned copied,
389                                 struct page *page, void *fsdata);
390 
391 struct address_space {
392         struct inode            *host;          /* owner: inode, block_device */
393         struct radix_tree_root  page_tree;      /* radix tree of all pages */
394         spinlock_t              tree_lock;      /* and lock protecting it */
395         atomic_t                i_mmap_writable;/* count VM_SHARED mappings */
396         struct rb_root_cached   i_mmap;         /* tree of private and shared mappings */
397         struct rw_semaphore     i_mmap_rwsem;   /* protect tree, count, list */
398         /* Protected by tree_lock together with the radix tree */
399         unsigned long           nrpages;        /* number of total pages */
400         /* number of shadow or DAX exceptional entries */
401         unsigned long           nrexceptional;
402         pgoff_t                 writeback_index;/* writeback starts here */
403         const struct address_space_operations *a_ops;   /* methods */
404         unsigned long           flags;          /* error bits */
405         spinlock_t              private_lock;   /* for use by the address_space */
406         gfp_t                   gfp_mask;       /* implicit gfp mask for allocations */
407         struct list_head        private_list;   /* for use by the address_space */
408         void                    *private_data;  /* ditto */
409         errseq_t                wb_err;
410 } __attribute__((aligned(sizeof(long)))) __randomize_layout;
411         /*
412          * On most architectures that alignment is already the case; but
413          * must be enforced here for CRIS, to let the least significant bit
414          * of struct page's "mapping" pointer be used for PAGE_MAPPING_ANON.
415          */
416 struct request_queue;
417 
418 struct block_device {
419         dev_t                   bd_dev;  /* not a kdev_t - it's a search key */
420         int                     bd_openers;
421         struct inode *          bd_inode;       /* will die */
422         struct super_block *    bd_super;
423         struct mutex            bd_mutex;       /* open/close mutex */
424         void *                  bd_claiming;
425         void *                  bd_holder;
426         int                     bd_holders;
427         bool                    bd_write_holder;
428 #ifdef CONFIG_SYSFS
429         struct list_head        bd_holder_disks;
430 #endif
431         struct block_device *   bd_contains;
432         unsigned                bd_block_size;
433         u8                      bd_partno;
434         struct hd_struct *      bd_part;
435         /* number of times partitions within this device have been opened. */
436         unsigned                bd_part_count;
437         int                     bd_invalidated;
438         struct gendisk *        bd_disk;
439         struct request_queue *  bd_queue;
440         struct backing_dev_info *bd_bdi;
441         struct list_head        bd_list;
442         /*
443          * Private data.  You must have bd_claim'ed the block_device
444          * to use this.  NOTE:  bd_claim allows an owner to claim
445          * the same device multiple times, the owner must take special
446          * care to not mess up bd_private for that case.
447          */
448         unsigned long           bd_private;
449 
450         /* The counter of freeze processes */
451         int                     bd_fsfreeze_count;
452         /* Mutex for freeze */
453         struct mutex            bd_fsfreeze_mutex;
454 } __randomize_layout;
455 
456 /*
457  * Radix-tree tags, for tagging dirty and writeback pages within the pagecache
458  * radix trees
459  */
460 #define PAGECACHE_TAG_DIRTY     0
461 #define PAGECACHE_TAG_WRITEBACK 1
462 #define PAGECACHE_TAG_TOWRITE   2
463 
464 int mapping_tagged(struct address_space *mapping, int tag);
465 
466 static inline void i_mmap_lock_write(struct address_space *mapping)
467 {
468         down_write(&mapping->i_mmap_rwsem);
469 }
470 
471 static inline void i_mmap_unlock_write(struct address_space *mapping)
472 {
473         up_write(&mapping->i_mmap_rwsem);
474 }
475 
476 static inline void i_mmap_lock_read(struct address_space *mapping)
477 {
478         down_read(&mapping->i_mmap_rwsem);
479 }
480 
481 static inline void i_mmap_unlock_read(struct address_space *mapping)
482 {
483         up_read(&mapping->i_mmap_rwsem);
484 }
485 
486 /*
487  * Might pages of this file be mapped into userspace?
488  */
489 static inline int mapping_mapped(struct address_space *mapping)
490 {
491         return  !RB_EMPTY_ROOT(&mapping->i_mmap.rb_root);
492 }
493 
494 /*
495  * Might pages of this file have been modified in userspace?
496  * Note that i_mmap_writable counts all VM_SHARED vmas: do_mmap_pgoff
497  * marks vma as VM_SHARED if it is shared, and the file was opened for
498  * writing i.e. vma may be mprotected writable even if now readonly.
499  *
500  * If i_mmap_writable is negative, no new writable mappings are allowed. You
501  * can only deny writable mappings, if none exists right now.
502  */
503 static inline int mapping_writably_mapped(struct address_space *mapping)
504 {
505         return atomic_read(&mapping->i_mmap_writable) > 0;
506 }
507 
508 static inline int mapping_map_writable(struct address_space *mapping)
509 {
510         return atomic_inc_unless_negative(&mapping->i_mmap_writable) ?
511                 0 : -EPERM;
512 }
513 
514 static inline void mapping_unmap_writable(struct address_space *mapping)
515 {
516         atomic_dec(&mapping->i_mmap_writable);
517 }
518 
519 static inline int mapping_deny_writable(struct address_space *mapping)
520 {
521         return atomic_dec_unless_positive(&mapping->i_mmap_writable) ?
522                 0 : -EBUSY;
523 }
524 
525 static inline void mapping_allow_writable(struct address_space *mapping)
526 {
527         atomic_inc(&mapping->i_mmap_writable);
528 }
529 
530 /*
531  * Use sequence counter to get consistent i_size on 32-bit processors.
532  */
533 #if BITS_PER_LONG==32 && defined(CONFIG_SMP)
534 #include <linux/seqlock.h>
535 #define __NEED_I_SIZE_ORDERED
536 #define i_size_ordered_init(inode) seqcount_init(&inode->i_size_seqcount)
537 #else
538 #define i_size_ordered_init(inode) do { } while (0)
539 #endif
540 
541 struct posix_acl;
542 #define ACL_NOT_CACHED ((void *)(-1))
543 #define ACL_DONT_CACHE ((void *)(-3))
544 
545 static inline struct posix_acl *
546 uncached_acl_sentinel(struct task_struct *task)
547 {
548         return (void *)task + 1;
549 }
550 
551 static inline bool
552 is_uncached_acl(struct posix_acl *acl)
553 {
554         return (long)acl & 1;
555 }
556 
557 #define IOP_FASTPERM    0x0001
558 #define IOP_LOOKUP      0x0002
559 #define IOP_NOFOLLOW    0x0004
560 #define IOP_XATTR       0x0008
561 #define IOP_DEFAULT_READLINK    0x0010
562 
563 struct fsnotify_mark_connector;
564 
565 /*
566  * Keep mostly read-only and often accessed (especially for
567  * the RCU path lookup and 'stat' data) fields at the beginning
568  * of the 'struct inode'
569  */
570 struct inode {
571         umode_t                 i_mode;
572         unsigned short          i_opflags;
573         kuid_t                  i_uid;
574         kgid_t                  i_gid;
575         unsigned int            i_flags;
576 
577 #ifdef CONFIG_FS_POSIX_ACL
578         struct posix_acl        *i_acl;
579         struct posix_acl        *i_default_acl;
580 #endif
581 
582         const struct inode_operations   *i_op;
583         struct super_block      *i_sb;
584         struct address_space    *i_mapping;
585 
586 #ifdef CONFIG_SECURITY
587         void                    *i_security;
588 #endif
589 
590         /* Stat data, not accessed from path walking */
591         unsigned long           i_ino;
592         /*
593          * Filesystems may only read i_nlink directly.  They shall use the
594          * following functions for modification:
595          *
596          *    (set|clear|inc|drop)_nlink
597          *    inode_(inc|dec)_link_count
598          */
599         union {
600                 const unsigned int i_nlink;
601                 unsigned int __i_nlink;
602         };
603         dev_t                   i_rdev;
604         loff_t                  i_size;
605         struct timespec         i_atime;
606         struct timespec         i_mtime;
607         struct timespec         i_ctime;
608         spinlock_t              i_lock; /* i_blocks, i_bytes, maybe i_size */
609         unsigned short          i_bytes;
610         unsigned int            i_blkbits;
611         enum rw_hint            i_write_hint;
612         blkcnt_t                i_blocks;
613 
614 #ifdef __NEED_I_SIZE_ORDERED
615         seqcount_t              i_size_seqcount;
616 #endif
617 
618         /* Misc */
619         unsigned long           i_state;
620         struct rw_semaphore     i_rwsem;
621 
622         unsigned long           dirtied_when;   /* jiffies of first dirtying */
623         unsigned long           dirtied_time_when;
624 
625         struct hlist_node       i_hash;
626         struct list_head        i_io_list;      /* backing dev IO list */
627 #ifdef CONFIG_CGROUP_WRITEBACK
628         struct bdi_writeback    *i_wb;          /* the associated cgroup wb */
629 
630         /* foreign inode detection, see wbc_detach_inode() */
631         int                     i_wb_frn_winner;
632         u16                     i_wb_frn_avg_time;
633         u16                     i_wb_frn_history;
634 #endif
635         struct list_head        i_lru;          /* inode LRU list */
636         struct list_head        i_sb_list;
637         struct list_head        i_wb_list;      /* backing dev writeback list */
638         union {
639                 struct hlist_head       i_dentry;
640                 struct rcu_head         i_rcu;
641         };
642         u64                     i_version;
643         atomic_t                i_count;
644         atomic_t                i_dio_count;
645         atomic_t                i_writecount;
646 #ifdef CONFIG_IMA
647         atomic_t                i_readcount; /* struct files open RO */
648 #endif
649         const struct file_operations    *i_fop; /* former ->i_op->default_file_ops */
650         struct file_lock_context        *i_flctx;
651         struct address_space    i_data;
652         struct list_head        i_devices;
653         union {
654                 struct pipe_inode_info  *i_pipe;
655                 struct block_device     *i_bdev;
656                 struct cdev             *i_cdev;
657                 char                    *i_link;
658                 unsigned                i_dir_seq;
659         };
660 
661         __u32                   i_generation;
662 
663 #ifdef CONFIG_FSNOTIFY
664         __u32                   i_fsnotify_mask; /* all events this inode cares about */
665         struct fsnotify_mark_connector __rcu    *i_fsnotify_marks;
666 #endif
667 
668 #if IS_ENABLED(CONFIG_FS_ENCRYPTION)
669         struct fscrypt_info     *i_crypt_info;
670 #endif
671 
672         void                    *i_private; /* fs or device private pointer */
673 } __randomize_layout;
674 
675 static inline unsigned int i_blocksize(const struct inode *node)
676 {
677         return (1 << node->i_blkbits);
678 }
679 
680 static inline int inode_unhashed(struct inode *inode)
681 {
682         return hlist_unhashed(&inode->i_hash);
683 }
684 
685 /*
686  * inode->i_mutex nesting subclasses for the lock validator:
687  *
688  * 0: the object of the current VFS operation
689  * 1: parent
690  * 2: child/target
691  * 3: xattr
692  * 4: second non-directory
693  * 5: second parent (when locking independent directories in rename)
694  *
695  * I_MUTEX_NONDIR2 is for certain operations (such as rename) which lock two
696  * non-directories at once.
697  *
698  * The locking order between these classes is
699  * parent[2] -> child -> grandchild -> normal -> xattr -> second non-directory
700  */
701 enum inode_i_mutex_lock_class
702 {
703         I_MUTEX_NORMAL,
704         I_MUTEX_PARENT,
705         I_MUTEX_CHILD,
706         I_MUTEX_XATTR,
707         I_MUTEX_NONDIR2,
708         I_MUTEX_PARENT2,
709 };
710 
711 static inline void inode_lock(struct inode *inode)
712 {
713         down_write(&inode->i_rwsem);
714 }
715 
716 static inline void inode_unlock(struct inode *inode)
717 {
718         up_write(&inode->i_rwsem);
719 }
720 
721 static inline void inode_lock_shared(struct inode *inode)
722 {
723         down_read(&inode->i_rwsem);
724 }
725 
726 static inline void inode_unlock_shared(struct inode *inode)
727 {
728         up_read(&inode->i_rwsem);
729 }
730 
731 static inline int inode_trylock(struct inode *inode)
732 {
733         return down_write_trylock(&inode->i_rwsem);
734 }
735 
736 static inline int inode_trylock_shared(struct inode *inode)
737 {
738         return down_read_trylock(&inode->i_rwsem);
739 }
740 
741 static inline int inode_is_locked(struct inode *inode)
742 {
743         return rwsem_is_locked(&inode->i_rwsem);
744 }
745 
746 static inline void inode_lock_nested(struct inode *inode, unsigned subclass)
747 {
748         down_write_nested(&inode->i_rwsem, subclass);
749 }
750 
751 void lock_two_nondirectories(struct inode *, struct inode*);
752 void unlock_two_nondirectories(struct inode *, struct inode*);
753 
754 /*
755  * NOTE: in a 32bit arch with a preemptable kernel and
756  * an UP compile the i_size_read/write must be atomic
757  * with respect to the local cpu (unlike with preempt disabled),
758  * but they don't need to be atomic with respect to other cpus like in
759  * true SMP (so they need either to either locally disable irq around
760  * the read or for example on x86 they can be still implemented as a
761  * cmpxchg8b without the need of the lock prefix). For SMP compiles
762  * and 64bit archs it makes no difference if preempt is enabled or not.
763  */
764 static inline loff_t i_size_read(const struct inode *inode)
765 {
766 #if BITS_PER_LONG==32 && defined(CONFIG_SMP)
767         loff_t i_size;
768         unsigned int seq;
769 
770         do {
771                 seq = read_seqcount_begin(&inode->i_size_seqcount);
772                 i_size = inode->i_size;
773         } while (read_seqcount_retry(&inode->i_size_seqcount, seq));
774         return i_size;
775 #elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPT)
776         loff_t i_size;
777 
778         preempt_disable();
779         i_size = inode->i_size;
780         preempt_enable();
781         return i_size;
782 #else
783         return inode->i_size;
784 #endif
785 }
786 
787 /*
788  * NOTE: unlike i_size_read(), i_size_write() does need locking around it
789  * (normally i_mutex), otherwise on 32bit/SMP an update of i_size_seqcount
790  * can be lost, resulting in subsequent i_size_read() calls spinning forever.
791  */
792 static inline void i_size_write(struct inode *inode, loff_t i_size)
793 {
794 #if BITS_PER_LONG==32 && defined(CONFIG_SMP)
795         preempt_disable();
796         write_seqcount_begin(&inode->i_size_seqcount);
797         inode->i_size = i_size;
798         write_seqcount_end(&inode->i_size_seqcount);
799         preempt_enable();
800 #elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPT)
801         preempt_disable();
802         inode->i_size = i_size;
803         preempt_enable();
804 #else
805         inode->i_size = i_size;
806 #endif
807 }
808 
809 static inline unsigned iminor(const struct inode *inode)
810 {
811         return MINOR(inode->i_rdev);
812 }
813 
814 static inline unsigned imajor(const struct inode *inode)
815 {
816         return MAJOR(inode->i_rdev);
817 }
818 
819 extern struct block_device *I_BDEV(struct inode *inode);
820 
821 struct fown_struct {
822         rwlock_t lock;          /* protects pid, uid, euid fields */
823         struct pid *pid;        /* pid or -pgrp where SIGIO should be sent */
824         enum pid_type pid_type; /* Kind of process group SIGIO should be sent to */
825         kuid_t uid, euid;       /* uid/euid of process setting the owner */
826         int signum;             /* posix.1b rt signal to be delivered on IO */
827 };
828 
829 /*
830  * Track a single file's readahead state
831  */
832 struct file_ra_state {
833         pgoff_t start;                  /* where readahead started */
834         unsigned int size;              /* # of readahead pages */
835         unsigned int async_size;        /* do asynchronous readahead when
836                                            there are only # of pages ahead */
837 
838         unsigned int ra_pages;          /* Maximum readahead window */
839         unsigned int mmap_miss;         /* Cache miss stat for mmap accesses */
840         loff_t prev_pos;                /* Cache last read() position */
841 };
842 
843 /*
844  * Check if @index falls in the readahead windows.
845  */
846 static inline int ra_has_index(struct file_ra_state *ra, pgoff_t index)
847 {
848         return (index >= ra->start &&
849                 index <  ra->start + ra->size);
850 }
851 
852 struct file {
853         union {
854                 struct llist_node       fu_llist;
855                 struct rcu_head         fu_rcuhead;
856         } f_u;
857         struct path             f_path;
858         struct inode            *f_inode;       /* cached value */
859         const struct file_operations    *f_op;
860 
861         /*
862          * Protects f_ep_links, f_flags.
863          * Must not be taken from IRQ context.
864          */
865         spinlock_t              f_lock;
866         enum rw_hint            f_write_hint;
867         atomic_long_t           f_count;
868         unsigned int            f_flags;
869         fmode_t                 f_mode;
870         struct mutex            f_pos_lock;
871         loff_t                  f_pos;
872         struct fown_struct      f_owner;
873         const struct cred       *f_cred;
874         struct file_ra_state    f_ra;
875 
876         u64                     f_version;
877 #ifdef CONFIG_SECURITY
878         void                    *f_security;
879 #endif
880         /* needed for tty driver, and maybe others */
881         void                    *private_data;
882 
883 #ifdef CONFIG_EPOLL
884         /* Used by fs/eventpoll.c to link all the hooks to this file */
885         struct list_head        f_ep_links;
886         struct list_head        f_tfile_llink;
887 #endif /* #ifdef CONFIG_EPOLL */
888         struct address_space    *f_mapping;
889         errseq_t                f_wb_err;
890 } __randomize_layout
891   __attribute__((aligned(4)));  /* lest something weird decides that 2 is OK */
892 
893 struct file_handle {
894         __u32 handle_bytes;
895         int handle_type;
896         /* file identifier */
897         unsigned char f_handle[0];
898 };
899 
900 static inline struct file *get_file(struct file *f)
901 {
902         atomic_long_inc(&f->f_count);
903         return f;
904 }
905 #define get_file_rcu(x) atomic_long_inc_not_zero(&(x)->f_count)
906 #define fput_atomic(x)  atomic_long_add_unless(&(x)->f_count, -1, 1)
907 #define file_count(x)   atomic_long_read(&(x)->f_count)
908 
909 #define MAX_NON_LFS     ((1UL<<31) - 1)
910 
911 /* Page cache limit. The filesystems should put that into their s_maxbytes 
912    limits, otherwise bad things can happen in VM. */ 
913 #if BITS_PER_LONG==32
914 #define MAX_LFS_FILESIZE        ((loff_t)ULONG_MAX << PAGE_SHIFT)
915 #elif BITS_PER_LONG==64
916 #define MAX_LFS_FILESIZE        ((loff_t)LLONG_MAX)
917 #endif
918 
919 #define FL_POSIX        1
920 #define FL_FLOCK        2
921 #define FL_DELEG        4       /* NFSv4 delegation */
922 #define FL_ACCESS       8       /* not trying to lock, just looking */
923 #define FL_EXISTS       16      /* when unlocking, test for existence */
924 #define FL_LEASE        32      /* lease held on this file */
925 #define FL_CLOSE        64      /* unlock on close */
926 #define FL_SLEEP        128     /* A blocking lock */
927 #define FL_DOWNGRADE_PENDING    256 /* Lease is being downgraded */
928 #define FL_UNLOCK_PENDING       512 /* Lease is being broken */
929 #define FL_OFDLCK       1024    /* lock is "owned" by struct file */
930 #define FL_LAYOUT       2048    /* outstanding pNFS layout */
931 
932 #define FL_CLOSE_POSIX (FL_POSIX | FL_CLOSE)
933 
934 /*
935  * Special return value from posix_lock_file() and vfs_lock_file() for
936  * asynchronous locking.
937  */
938 #define FILE_LOCK_DEFERRED 1
939 
940 /* legacy typedef, should eventually be removed */
941 typedef void *fl_owner_t;
942 
943 struct file_lock;
944 
945 struct file_lock_operations {
946         void (*fl_copy_lock)(struct file_lock *, struct file_lock *);
947         void (*fl_release_private)(struct file_lock *);
948 };
949 
950 struct lock_manager_operations {
951         int (*lm_compare_owner)(struct file_lock *, struct file_lock *);
952         unsigned long (*lm_owner_key)(struct file_lock *);
953         fl_owner_t (*lm_get_owner)(fl_owner_t);
954         void (*lm_put_owner)(fl_owner_t);
955         void (*lm_notify)(struct file_lock *);  /* unblock callback */
956         int (*lm_grant)(struct file_lock *, int);
957         bool (*lm_break)(struct file_lock *);
958         int (*lm_change)(struct file_lock *, int, struct list_head *);
959         void (*lm_setup)(struct file_lock *, void **);
960 };
961 
962 struct lock_manager {
963         struct list_head list;
964         /*
965          * NFSv4 and up also want opens blocked during the grace period;
966          * NLM doesn't care:
967          */
968         bool block_opens;
969 };
970 
971 struct net;
972 void locks_start_grace(struct net *, struct lock_manager *);
973 void locks_end_grace(struct lock_manager *);
974 bool locks_in_grace(struct net *);
975 bool opens_in_grace(struct net *);
976 
977 /* that will die - we need it for nfs_lock_info */
978 #include <linux/nfs_fs_i.h>
979 
980 /*
981  * struct file_lock represents a generic "file lock". It's used to represent
982  * POSIX byte range locks, BSD (flock) locks, and leases. It's important to
983  * note that the same struct is used to represent both a request for a lock and
984  * the lock itself, but the same object is never used for both.
985  *
986  * FIXME: should we create a separate "struct lock_request" to help distinguish
987  * these two uses?
988  *
989  * The varous i_flctx lists are ordered by:
990  *
991  * 1) lock owner
992  * 2) lock range start
993  * 3) lock range end
994  *
995  * Obviously, the last two criteria only matter for POSIX locks.
996  */
997 struct file_lock {
998         struct file_lock *fl_next;      /* singly linked list for this inode  */
999         struct list_head fl_list;       /* link into file_lock_context */
1000         struct hlist_node fl_link;      /* node in global lists */
1001         struct list_head fl_block;      /* circular list of blocked processes */
1002         fl_owner_t fl_owner;
1003         unsigned int fl_flags;
1004         unsigned char fl_type;
1005         unsigned int fl_pid;
1006         int fl_link_cpu;                /* what cpu's list is this on? */
1007         wait_queue_head_t fl_wait;
1008         struct file *fl_file;
1009         loff_t fl_start;
1010         loff_t fl_end;
1011 
1012         struct fasync_struct *  fl_fasync; /* for lease break notifications */
1013         /* for lease breaks: */
1014         unsigned long fl_break_time;
1015         unsigned long fl_downgrade_time;
1016 
1017         const struct file_lock_operations *fl_ops;      /* Callbacks for filesystems */
1018         const struct lock_manager_operations *fl_lmops; /* Callbacks for lockmanagers */
1019         union {
1020                 struct nfs_lock_info    nfs_fl;
1021                 struct nfs4_lock_info   nfs4_fl;
1022                 struct {
1023                         struct list_head link;  /* link in AFS vnode's pending_locks list */
1024                         int state;              /* state of grant or error if -ve */
1025                 } afs;
1026         } fl_u;
1027 } __randomize_layout;
1028 
1029 struct file_lock_context {
1030         spinlock_t              flc_lock;
1031         struct list_head        flc_flock;
1032         struct list_head        flc_posix;
1033         struct list_head        flc_lease;
1034 };
1035 
1036 /* The following constant reflects the upper bound of the file/locking space */
1037 #ifndef OFFSET_MAX
1038 #define INT_LIMIT(x)    (~((x)1 << (sizeof(x)*8 - 1)))
1039 #define OFFSET_MAX      INT_LIMIT(loff_t)
1040 #define OFFT_OFFSET_MAX INT_LIMIT(off_t)
1041 #endif
1042 
1043 extern void send_sigio(struct fown_struct *fown, int fd, int band);
1044 
1045 /*
1046  * Return the inode to use for locking
1047  *
1048  * For overlayfs this should be the overlay inode, not the real inode returned
1049  * by file_inode().  For any other fs file_inode(filp) and locks_inode(filp) are
1050  * equal.
1051  */
1052 static inline struct inode *locks_inode(const struct file *f)
1053 {
1054         return f->f_path.dentry->d_inode;
1055 }
1056 
1057 #ifdef CONFIG_FILE_LOCKING
1058 extern int fcntl_getlk(struct file *, unsigned int, struct flock *);
1059 extern int fcntl_setlk(unsigned int, struct file *, unsigned int,
1060                         struct flock *);
1061 
1062 #if BITS_PER_LONG == 32
1063 extern int fcntl_getlk64(struct file *, unsigned int, struct flock64 *);
1064 extern int fcntl_setlk64(unsigned int, struct file *, unsigned int,
1065                         struct flock64 *);
1066 #endif
1067 
1068 extern int fcntl_setlease(unsigned int fd, struct file *filp, long arg);
1069 extern int fcntl_getlease(struct file *filp);
1070 
1071 /* fs/locks.c */
1072 void locks_free_lock_context(struct inode *inode);
1073 void locks_free_lock(struct file_lock *fl);
1074 extern void locks_init_lock(struct file_lock *);
1075 extern struct file_lock * locks_alloc_lock(void);
1076 extern void locks_copy_lock(struct file_lock *, struct file_lock *);
1077 extern void locks_copy_conflock(struct file_lock *, struct file_lock *);
1078 extern void locks_remove_posix(struct file *, fl_owner_t);
1079 extern void locks_remove_file(struct file *);
1080 extern void locks_release_private(struct file_lock *);
1081 extern void posix_test_lock(struct file *, struct file_lock *);
1082 extern int posix_lock_file(struct file *, struct file_lock *, struct file_lock *);
1083 extern int posix_unblock_lock(struct file_lock *);
1084 extern int vfs_test_lock(struct file *, struct file_lock *);
1085 extern int vfs_lock_file(struct file *, unsigned int, struct file_lock *, struct file_lock *);
1086 extern int vfs_cancel_lock(struct file *filp, struct file_lock *fl);
1087 extern int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl);
1088 extern int __break_lease(struct inode *inode, unsigned int flags, unsigned int type);
1089 extern void lease_get_mtime(struct inode *, struct timespec *time);
1090 extern int generic_setlease(struct file *, long, struct file_lock **, void **priv);
1091 extern int vfs_setlease(struct file *, long, struct file_lock **, void **);
1092 extern int lease_modify(struct file_lock *, int, struct list_head *);
1093 struct files_struct;
1094 extern void show_fd_locks(struct seq_file *f,
1095                          struct file *filp, struct files_struct *files);
1096 #else /* !CONFIG_FILE_LOCKING */
1097 static inline int fcntl_getlk(struct file *file, unsigned int cmd,
1098                               struct flock __user *user)
1099 {
1100         return -EINVAL;
1101 }
1102 
1103 static inline int fcntl_setlk(unsigned int fd, struct file *file,
1104                               unsigned int cmd, struct flock __user *user)
1105 {
1106         return -EACCES;
1107 }
1108 
1109 #if BITS_PER_LONG == 32
1110 static inline int fcntl_getlk64(struct file *file, unsigned int cmd,
1111                                 struct flock64 __user *user)
1112 {
1113         return -EINVAL;
1114 }
1115 
1116 static inline int fcntl_setlk64(unsigned int fd, struct file *file,
1117                                 unsigned int cmd, struct flock64 __user *user)
1118 {
1119         return -EACCES;
1120 }
1121 #endif
1122 static inline int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
1123 {
1124         return -EINVAL;
1125 }
1126 
1127 static inline int fcntl_getlease(struct file *filp)
1128 {
1129         return F_UNLCK;
1130 }
1131 
1132 static inline void
1133 locks_free_lock_context(struct inode *inode)
1134 {
1135 }
1136 
1137 static inline void locks_init_lock(struct file_lock *fl)
1138 {
1139         return;
1140 }
1141 
1142 static inline void locks_copy_conflock(struct file_lock *new, struct file_lock *fl)
1143 {
1144         return;
1145 }
1146 
1147 static inline void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
1148 {
1149         return;
1150 }
1151 
1152 static inline void locks_remove_posix(struct file *filp, fl_owner_t owner)
1153 {
1154         return;
1155 }
1156 
1157 static inline void locks_remove_file(struct file *filp)
1158 {
1159         return;
1160 }
1161 
1162 static inline void posix_test_lock(struct file *filp, struct file_lock *fl)
1163 {
1164         return;
1165 }
1166 
1167 static inline int posix_lock_file(struct file *filp, struct file_lock *fl,
1168                                   struct file_lock *conflock)
1169 {
1170         return -ENOLCK;
1171 }
1172 
1173 static inline int posix_unblock_lock(struct file_lock *waiter)
1174 {
1175         return -ENOENT;
1176 }
1177 
1178 static inline int vfs_test_lock(struct file *filp, struct file_lock *fl)
1179 {
1180         return 0;
1181 }
1182 
1183 static inline int vfs_lock_file(struct file *filp, unsigned int cmd,
1184                                 struct file_lock *fl, struct file_lock *conf)
1185 {
1186         return -ENOLCK;
1187 }
1188 
1189 static inline int vfs_cancel_lock(struct file *filp, struct file_lock *fl)
1190 {
1191         return 0;
1192 }
1193 
1194 static inline int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl)
1195 {
1196         return -ENOLCK;
1197 }
1198 
1199 static inline int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
1200 {
1201         return 0;
1202 }
1203 
1204 static inline void lease_get_mtime(struct inode *inode, struct timespec *time)
1205 {
1206         return;
1207 }
1208 
1209 static inline int generic_setlease(struct file *filp, long arg,
1210                                     struct file_lock **flp, void **priv)
1211 {
1212         return -EINVAL;
1213 }
1214 
1215 static inline int vfs_setlease(struct file *filp, long arg,
1216                                struct file_lock **lease, void **priv)
1217 {
1218         return -EINVAL;
1219 }
1220 
1221 static inline int lease_modify(struct file_lock *fl, int arg,
1222                                struct list_head *dispose)
1223 {
1224         return -EINVAL;
1225 }
1226 
1227 struct files_struct;
1228 static inline void show_fd_locks(struct seq_file *f,
1229                         struct file *filp, struct files_struct *files) {}
1230 #endif /* !CONFIG_FILE_LOCKING */
1231 
1232 static inline struct inode *file_inode(const struct file *f)
1233 {
1234         return f->f_inode;
1235 }
1236 
1237 static inline struct dentry *file_dentry(const struct file *file)
1238 {
1239         return d_real(file->f_path.dentry, file_inode(file), 0, 0);
1240 }
1241 
1242 static inline int locks_lock_file_wait(struct file *filp, struct file_lock *fl)
1243 {
1244         return locks_lock_inode_wait(locks_inode(filp), fl);
1245 }
1246 
1247 struct fasync_struct {
1248         spinlock_t              fa_lock;
1249         int                     magic;
1250         int                     fa_fd;
1251         struct fasync_struct    *fa_next; /* singly linked list */
1252         struct file             *fa_file;
1253         struct rcu_head         fa_rcu;
1254 };
1255 
1256 #define FASYNC_MAGIC 0x4601
1257 
1258 /* SMP safe fasync helpers: */
1259 extern int fasync_helper(int, struct file *, int, struct fasync_struct **);
1260 extern struct fasync_struct *fasync_insert_entry(int, struct file *, struct fasync_struct **, struct fasync_struct *);
1261 extern int fasync_remove_entry(struct file *, struct fasync_struct **);
1262 extern struct fasync_struct *fasync_alloc(void);
1263 extern void fasync_free(struct fasync_struct *);
1264 
1265 /* can be called from interrupts */
1266 extern void kill_fasync(struct fasync_struct **, int, int);
1267 
1268 extern void __f_setown(struct file *filp, struct pid *, enum pid_type, int force);
1269 extern int f_setown(struct file *filp, unsigned long arg, int force);
1270 extern void f_delown(struct file *filp);
1271 extern pid_t f_getown(struct file *filp);
1272 extern int send_sigurg(struct fown_struct *fown);
1273 
1274 /*
1275  * sb->s_flags.  Note that these mirror the equivalent MS_* flags where
1276  * represented in both.
1277  */
1278 #define SB_RDONLY        1      /* Mount read-only */
1279 #define SB_NOSUID        2      /* Ignore suid and sgid bits */
1280 #define SB_NODEV         4      /* Disallow access to device special files */
1281 #define SB_NOEXEC        8      /* Disallow program execution */
1282 #define SB_SYNCHRONOUS  16      /* Writes are synced at once */
1283 #define SB_MANDLOCK     64      /* Allow mandatory locks on an FS */
1284 #define SB_DIRSYNC      128     /* Directory modifications are synchronous */
1285 #define SB_NOATIME      1024    /* Do not update access times. */
1286 #define SB_NODIRATIME   2048    /* Do not update directory access times */
1287 #define SB_SILENT       32768
1288 #define SB_POSIXACL     (1<<16) /* VFS does not apply the umask */
1289 #define SB_KERNMOUNT    (1<<22) /* this is a kern_mount call */
1290 #define SB_I_VERSION    (1<<23) /* Update inode I_version field */
1291 #define SB_LAZYTIME     (1<<25) /* Update the on-disk [acm]times lazily */
1292 
1293 /* These sb flags are internal to the kernel */
1294 #define SB_SUBMOUNT     (1<<26)
1295 #define SB_NOREMOTELOCK (1<<27)
1296 #define SB_NOSEC        (1<<28)
1297 #define SB_BORN         (1<<29)
1298 #define SB_ACTIVE       (1<<30)
1299 #define SB_NOUSER       (1<<31)
1300 
1301 /*
1302  *      Umount options
1303  */
1304 
1305 #define MNT_FORCE       0x00000001      /* Attempt to forcibily umount */
1306 #define MNT_DETACH      0x00000002      /* Just detach from the tree */
1307 #define MNT_EXPIRE      0x00000004      /* Mark for expiry */
1308 #define UMOUNT_NOFOLLOW 0x00000008      /* Don't follow symlink on umount */
1309 #define UMOUNT_UNUSED   0x80000000      /* Flag guaranteed to be unused */
1310 
1311 /* sb->s_iflags */
1312 #define SB_I_CGROUPWB   0x00000001      /* cgroup-aware writeback enabled */
1313 #define SB_I_NOEXEC     0x00000002      /* Ignore executables on this fs */
1314 #define SB_I_NODEV      0x00000004      /* Ignore devices on this fs */
1315 #define SB_I_MULTIROOT  0x00000008      /* Multiple roots to the dentry tree */
1316 
1317 /* sb->s_iflags to limit user namespace mounts */
1318 #define SB_I_USERNS_VISIBLE             0x00000010 /* fstype already mounted */
1319 
1320 /* Possible states of 'frozen' field */
1321 enum {
1322         SB_UNFROZEN = 0,                /* FS is unfrozen */
1323         SB_FREEZE_WRITE = 1,            /* Writes, dir ops, ioctls frozen */
1324         SB_FREEZE_PAGEFAULT = 2,        /* Page faults stopped as well */
1325         SB_FREEZE_FS = 3,               /* For internal FS use (e.g. to stop
1326                                          * internal threads if needed) */
1327         SB_FREEZE_COMPLETE = 4,         /* ->freeze_fs finished successfully */
1328 };
1329 
1330 #define SB_FREEZE_LEVELS (SB_FREEZE_COMPLETE - 1)
1331 
1332 struct sb_writers {
1333         int                             frozen;         /* Is sb frozen? */
1334         wait_queue_head_t               wait_unfrozen;  /* for get_super_thawed() */
1335         struct percpu_rw_semaphore      rw_sem[SB_FREEZE_LEVELS];
1336 };
1337 
1338 struct super_block {
1339         struct list_head        s_list;         /* Keep this first */
1340         dev_t                   s_dev;          /* search index; _not_ kdev_t */
1341         unsigned char           s_blocksize_bits;
1342         unsigned long           s_blocksize;
1343         loff_t                  s_maxbytes;     /* Max file size */
1344         struct file_system_type *s_type;
1345         const struct super_operations   *s_op;
1346         const struct dquot_operations   *dq_op;
1347         const struct quotactl_ops       *s_qcop;
1348         const struct export_operations *s_export_op;
1349         unsigned long           s_flags;
1350         unsigned long           s_iflags;       /* internal SB_I_* flags */
1351         unsigned long           s_magic;
1352         struct dentry           *s_root;
1353         struct rw_semaphore     s_umount;
1354         int                     s_count;
1355         atomic_t                s_active;
1356 #ifdef CONFIG_SECURITY
1357         void                    *s_security;
1358 #endif
1359         const struct xattr_handler **s_xattr;
1360 
1361         const struct fscrypt_operations *s_cop;
1362 
1363         struct hlist_bl_head    s_anon;         /* anonymous dentries for (nfs) exporting */
1364         struct list_head        s_mounts;       /* list of mounts; _not_ for fs use */
1365         struct block_device     *s_bdev;
1366         struct backing_dev_info *s_bdi;
1367         struct mtd_info         *s_mtd;
1368         struct hlist_node       s_instances;
1369         unsigned int            s_quota_types;  /* Bitmask of supported quota types */
1370         struct quota_info       s_dquot;        /* Diskquota specific options */
1371 
1372         struct sb_writers       s_writers;
1373 
1374         char                    s_id[32];       /* Informational name */
1375         uuid_t                  s_uuid;         /* UUID */
1376 
1377         void                    *s_fs_info;     /* Filesystem private info */
1378         unsigned int            s_max_links;
1379         fmode_t                 s_mode;
1380 
1381         /* Granularity of c/m/atime in ns.
1382            Cannot be worse than a second */
1383         u32                s_time_gran;
1384 
1385         /*
1386          * The next field is for VFS *only*. No filesystems have any business
1387          * even looking at it. You had been warned.
1388          */
1389         struct mutex s_vfs_rename_mutex;        /* Kludge */
1390 
1391         /*
1392          * Filesystem subtype.  If non-empty the filesystem type field
1393          * in /proc/mounts will be "type.subtype"
1394          */
1395         char *s_subtype;
1396 
1397         const struct dentry_operations *s_d_op; /* default d_op for dentries */
1398 
1399         /*
1400          * Saved pool identifier for cleancache (-1 means none)
1401          */
1402         int cleancache_poolid;
1403 
1404         struct shrinker s_shrink;       /* per-sb shrinker handle */
1405 
1406         /* Number of inodes with nlink == 0 but still referenced */
1407         atomic_long_t s_remove_count;
1408 
1409         /* Being remounted read-only */
1410         int s_readonly_remount;
1411 
1412         /* AIO completions deferred from interrupt context */
1413         struct workqueue_struct *s_dio_done_wq;
1414         struct hlist_head s_pins;
1415 
1416         /*
1417          * Owning user namespace and default context in which to
1418          * interpret filesystem uids, gids, quotas, device nodes,
1419          * xattrs and security labels.
1420          */
1421         struct user_namespace *s_user_ns;
1422 
1423         /*
1424          * Keep the lru lists last in the structure so they always sit on their
1425          * own individual cachelines.
1426          */
1427         struct list_lru         s_dentry_lru ____cacheline_aligned_in_smp;
1428         struct list_lru         s_inode_lru ____cacheline_aligned_in_smp;
1429         struct rcu_head         rcu;
1430         struct work_struct      destroy_work;
1431 
1432         struct mutex            s_sync_lock;    /* sync serialisation lock */
1433 
1434         /*
1435          * Indicates how deep in a filesystem stack this SB is
1436          */
1437         int s_stack_depth;
1438 
1439         /* s_inode_list_lock protects s_inodes */
1440         spinlock_t              s_inode_list_lock ____cacheline_aligned_in_smp;
1441         struct list_head        s_inodes;       /* all inodes */
1442 
1443         spinlock_t              s_inode_wblist_lock;
1444         struct list_head        s_inodes_wb;    /* writeback inodes */
1445 } __randomize_layout;
1446 
1447 /* Helper functions so that in most cases filesystems will
1448  * not need to deal directly with kuid_t and kgid_t and can
1449  * instead deal with the raw numeric values that are stored
1450  * in the filesystem.
1451  */
1452 static inline uid_t i_uid_read(const struct inode *inode)
1453 {
1454         return from_kuid(inode->i_sb->s_user_ns, inode->i_uid);
1455 }
1456 
1457 static inline gid_t i_gid_read(const struct inode *inode)
1458 {
1459         return from_kgid(inode->i_sb->s_user_ns, inode->i_gid);
1460 }
1461 
1462 static inline void i_uid_write(struct inode *inode, uid_t uid)
1463 {
1464         inode->i_uid = make_kuid(inode->i_sb->s_user_ns, uid);
1465 }
1466 
1467 static inline void i_gid_write(struct inode *inode, gid_t gid)
1468 {
1469         inode->i_gid = make_kgid(inode->i_sb->s_user_ns, gid);
1470 }
1471 
1472 extern struct timespec current_time(struct inode *inode);
1473 
1474 /*
1475  * Snapshotting support.
1476  */
1477 
1478 void __sb_end_write(struct super_block *sb, int level);
1479 int __sb_start_write(struct super_block *sb, int level, bool wait);
1480 
1481 #define __sb_writers_acquired(sb, lev)  \
1482         percpu_rwsem_acquire(&(sb)->s_writers.rw_sem[(lev)-1], 1, _THIS_IP_)
1483 #define __sb_writers_release(sb, lev)   \
1484         percpu_rwsem_release(&(sb)->s_writers.rw_sem[(lev)-1], 1, _THIS_IP_)
1485 
1486 /**
1487  * sb_end_write - drop write access to a superblock
1488  * @sb: the super we wrote to
1489  *
1490  * Decrement number of writers to the filesystem. Wake up possible waiters
1491  * wanting to freeze the filesystem.
1492  */
1493 static inline void sb_end_write(struct super_block *sb)
1494 {
1495         __sb_end_write(sb, SB_FREEZE_WRITE);
1496 }
1497 
1498 /**
1499  * sb_end_pagefault - drop write access to a superblock from a page fault
1500  * @sb: the super we wrote to
1501  *
1502  * Decrement number of processes handling write page fault to the filesystem.
1503  * Wake up possible waiters wanting to freeze the filesystem.
1504  */
1505 static inline void sb_end_pagefault(struct super_block *sb)
1506 {
1507         __sb_end_write(sb, SB_FREEZE_PAGEFAULT);
1508 }
1509 
1510 /**
1511  * sb_end_intwrite - drop write access to a superblock for internal fs purposes
1512  * @sb: the super we wrote to
1513  *
1514  * Decrement fs-internal number of writers to the filesystem.  Wake up possible
1515  * waiters wanting to freeze the filesystem.
1516  */
1517 static inline void sb_end_intwrite(struct super_block *sb)
1518 {
1519         __sb_end_write(sb, SB_FREEZE_FS);
1520 }
1521 
1522 /**
1523  * sb_start_write - get write access to a superblock
1524  * @sb: the super we write to
1525  *
1526  * When a process wants to write data or metadata to a file system (i.e. dirty
1527  * a page or an inode), it should embed the operation in a sb_start_write() -
1528  * sb_end_write() pair to get exclusion against file system freezing. This
1529  * function increments number of writers preventing freezing. If the file
1530  * system is already frozen, the function waits until the file system is
1531  * thawed.
1532  *
1533  * Since freeze protection behaves as a lock, users have to preserve
1534  * ordering of freeze protection and other filesystem locks. Generally,
1535  * freeze protection should be the outermost lock. In particular, we have:
1536  *
1537  * sb_start_write
1538  *   -> i_mutex                 (write path, truncate, directory ops, ...)
1539  *   -> s_umount                (freeze_super, thaw_super)
1540  */
1541 static inline void sb_start_write(struct super_block *sb)
1542 {
1543         __sb_start_write(sb, SB_FREEZE_WRITE, true);
1544 }
1545 
1546 static inline int sb_start_write_trylock(struct super_block *sb)
1547 {
1548         return __sb_start_write(sb, SB_FREEZE_WRITE, false);
1549 }
1550 
1551 /**
1552  * sb_start_pagefault - get write access to a superblock from a page fault
1553  * @sb: the super we write to
1554  *
1555  * When a process starts handling write page fault, it should embed the
1556  * operation into sb_start_pagefault() - sb_end_pagefault() pair to get
1557  * exclusion against file system freezing. This is needed since the page fault
1558  * is going to dirty a page. This function increments number of running page
1559  * faults preventing freezing. If the file system is already frozen, the
1560  * function waits until the file system is thawed.
1561  *
1562  * Since page fault freeze protection behaves as a lock, users have to preserve
1563  * ordering of freeze protection and other filesystem locks. It is advised to
1564  * put sb_start_pagefault() close to mmap_sem in lock ordering. Page fault
1565  * handling code implies lock dependency:
1566  *
1567  * mmap_sem
1568  *   -> sb_start_pagefault
1569  */
1570 static inline void sb_start_pagefault(struct super_block *sb)
1571 {
1572         __sb_start_write(sb, SB_FREEZE_PAGEFAULT, true);
1573 }
1574 
1575 /*
1576  * sb_start_intwrite - get write access to a superblock for internal fs purposes
1577  * @sb: the super we write to
1578  *
1579  * This is the third level of protection against filesystem freezing. It is
1580  * free for use by a filesystem. The only requirement is that it must rank
1581  * below sb_start_pagefault.
1582  *
1583  * For example filesystem can call sb_start_intwrite() when starting a
1584  * transaction which somewhat eases handling of freezing for internal sources
1585  * of filesystem changes (internal fs threads, discarding preallocation on file
1586  * close, etc.).
1587  */
1588 static inline void sb_start_intwrite(struct super_block *sb)
1589 {
1590         __sb_start_write(sb, SB_FREEZE_FS, true);
1591 }
1592 
1593 
1594 extern bool inode_owner_or_capable(const struct inode *inode);
1595 
1596 /*
1597  * VFS helper functions..
1598  */
1599 extern int vfs_create(struct inode *, struct dentry *, umode_t, bool);
1600 extern int vfs_mkdir(struct inode *, struct dentry *, umode_t);
1601 extern int vfs_mknod(struct inode *, struct dentry *, umode_t, dev_t);
1602 extern int vfs_symlink(struct inode *, struct dentry *, const char *);
1603 extern int vfs_link(struct dentry *, struct inode *, struct dentry *, struct inode **);
1604 extern int vfs_rmdir(struct inode *, struct dentry *);
1605 extern int vfs_unlink(struct inode *, struct dentry *, struct inode **);
1606 extern int vfs_rename(struct inode *, struct dentry *, struct inode *, struct dentry *, struct inode **, unsigned int);
1607 extern int vfs_whiteout(struct inode *, struct dentry *);
1608 
1609 extern struct dentry *vfs_tmpfile(struct dentry *dentry, umode_t mode,
1610                                   int open_flag);
1611 
1612 /*
1613  * VFS file helper functions.
1614  */
1615 extern void inode_init_owner(struct inode *inode, const struct inode *dir,
1616                         umode_t mode);
1617 extern bool may_open_dev(const struct path *path);
1618 /*
1619  * VFS FS_IOC_FIEMAP helper definitions.
1620  */
1621 struct fiemap_extent_info {
1622         unsigned int fi_flags;          /* Flags as passed from user */
1623         unsigned int fi_extents_mapped; /* Number of mapped extents */
1624         unsigned int fi_extents_max;    /* Size of fiemap_extent array */
1625         struct fiemap_extent __user *fi_extents_start; /* Start of
1626                                                         fiemap_extent array */
1627 };
1628 int fiemap_fill_next_extent(struct fiemap_extent_info *info, u64 logical,
1629                             u64 phys, u64 len, u32 flags);
1630 int fiemap_check_flags(struct fiemap_extent_info *fieinfo, u32 fs_flags);
1631 
1632 /*
1633  * File types
1634  *
1635  * NOTE! These match bits 12..15 of stat.st_mode
1636  * (ie "(i_mode >> 12) & 15").
1637  */
1638 #define DT_UNKNOWN      0
1639 #define DT_FIFO         1
1640 #define DT_CHR          2
1641 #define DT_DIR          4
1642 #define DT_BLK          6
1643 #define DT_REG          8
1644 #define DT_LNK          10
1645 #define DT_SOCK         12
1646 #define DT_WHT          14
1647 
1648 /*
1649  * This is the "filldir" function type, used by readdir() to let
1650  * the kernel specify what kind of dirent layout it wants to have.
1651  * This allows the kernel to read directories into kernel space or
1652  * to have different dirent layouts depending on the binary type.
1653  */
1654 struct dir_context;
1655 typedef int (*filldir_t)(struct dir_context *, const char *, int, loff_t, u64,
1656                          unsigned);
1657 
1658 struct dir_context {
1659         const filldir_t actor;
1660         loff_t pos;
1661 };
1662 
1663 struct block_device_operations;
1664 
1665 /* These macros are for out of kernel modules to test that
1666  * the kernel supports the unlocked_ioctl and compat_ioctl
1667  * fields in struct file_operations. */
1668 #define HAVE_COMPAT_IOCTL 1
1669 #define HAVE_UNLOCKED_IOCTL 1
1670 
1671 /*
1672  * These flags let !MMU mmap() govern direct device mapping vs immediate
1673  * copying more easily for MAP_PRIVATE, especially for ROM filesystems.
1674  *
1675  * NOMMU_MAP_COPY:      Copy can be mapped (MAP_PRIVATE)
1676  * NOMMU_MAP_DIRECT:    Can be mapped directly (MAP_SHARED)
1677  * NOMMU_MAP_READ:      Can be mapped for reading
1678  * NOMMU_MAP_WRITE:     Can be mapped for writing
1679  * NOMMU_MAP_EXEC:      Can be mapped for execution
1680  */
1681 #define NOMMU_MAP_COPY          0x00000001
1682 #define NOMMU_MAP_DIRECT        0x00000008
1683 #define NOMMU_MAP_READ          VM_MAYREAD
1684 #define NOMMU_MAP_WRITE         VM_MAYWRITE
1685 #define NOMMU_MAP_EXEC          VM_MAYEXEC
1686 
1687 #define NOMMU_VMFLAGS \
1688         (NOMMU_MAP_READ | NOMMU_MAP_WRITE | NOMMU_MAP_EXEC)
1689 
1690 
1691 struct iov_iter;
1692 
1693 struct file_operations {
1694         struct module *owner;
1695         loff_t (*llseek) (struct file *, loff_t, int);
1696         ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);
1697         ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
1698         ssize_t (*read_iter) (struct kiocb *, struct iov_iter *);
1699         ssize_t (*write_iter) (struct kiocb *, struct iov_iter *);
1700         int (*iterate) (struct file *, struct dir_context *);
1701         int (*iterate_shared) (struct file *, struct dir_context *);
1702         unsigned int (*poll) (struct file *, struct poll_table_struct *);
1703         long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
1704         long (*compat_ioctl) (struct file *, unsigned int, unsigned long);
1705         int (*mmap) (struct file *, struct vm_area_struct *);
1706         unsigned long mmap_supported_flags;
1707         int (*open) (struct inode *, struct file *);
1708         int (*flush) (struct file *, fl_owner_t id);
1709         int (*release) (struct inode *, struct file *);
1710         int (*fsync) (struct file *, loff_t, loff_t, int datasync);
1711         int (*fasync) (int, struct file *, int);
1712         int (*lock) (struct file *, int, struct file_lock *);
1713         ssize_t (*sendpage) (struct file *, struct page *, int, size_t, loff_t *, int);
1714         unsigned long (*get_unmapped_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
1715         int (*check_flags)(int);
1716         int (*flock) (struct file *, int, struct file_lock *);
1717         ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, loff_t *, size_t, unsigned int);
1718         ssize_t (*splice_read)(struct file *, loff_t *, struct pipe_inode_info *, size_t, unsigned int);
1719         int (*setlease)(struct file *, long, struct file_lock **, void **);
1720         long (*fallocate)(struct file *file, int mode, loff_t offset,
1721                           loff_t len);
1722         void (*show_fdinfo)(struct seq_file *m, struct file *f);
1723 #ifndef CONFIG_MMU
1724         unsigned (*mmap_capabilities)(struct file *);
1725 #endif
1726         ssize_t (*copy_file_range)(struct file *, loff_t, struct file *,
1727                         loff_t, size_t, unsigned int);
1728         int (*clone_file_range)(struct file *, loff_t, struct file *, loff_t,
1729                         u64);
1730         ssize_t (*dedupe_file_range)(struct file *, u64, u64, struct file *,
1731                         u64);
1732 } __randomize_layout;
1733 
1734 struct inode_operations {
1735         struct dentry * (*lookup) (struct inode *,struct dentry *, unsigned int);
1736         const char * (*get_link) (struct dentry *, struct inode *, struct delayed_call *);
1737         int (*permission) (struct inode *, int);
1738         struct posix_acl * (*get_acl)(struct inode *, int);
1739 
1740         int (*readlink) (struct dentry *, char __user *,int);
1741 
1742         int (*create) (struct inode *,struct dentry *, umode_t, bool);
1743         int (*link) (struct dentry *,struct inode *,struct dentry *);
1744         int (*unlink) (struct inode *,struct dentry *);
1745         int (*symlink) (struct inode *,struct dentry *,const char *);
1746         int (*mkdir) (struct inode *,struct dentry *,umode_t);
1747         int (*rmdir) (struct inode *,struct dentry *);
1748         int (*mknod) (struct inode *,struct dentry *,umode_t,dev_t);
1749         int (*rename) (struct inode *, struct dentry *,
1750                         struct inode *, struct dentry *, unsigned int);
1751         int (*setattr) (struct dentry *, struct iattr *);
1752         int (*getattr) (const struct path *, struct kstat *, u32, unsigned int);
1753         ssize_t (*listxattr) (struct dentry *, char *, size_t);
1754         int (*fiemap)(struct inode *, struct fiemap_extent_info *, u64 start,
1755                       u64 len);
1756         int (*update_time)(struct inode *, struct timespec *, int);
1757         int (*atomic_open)(struct inode *, struct dentry *,
1758                            struct file *, unsigned open_flag,
1759                            umode_t create_mode, int *opened);
1760         int (*tmpfile) (struct inode *, struct dentry *, umode_t);
1761         int (*set_acl)(struct inode *, struct posix_acl *, int);
1762 } ____cacheline_aligned;
1763 
1764 static inline ssize_t call_read_iter(struct file *file, struct kiocb *kio,
1765                                      struct iov_iter *iter)
1766 {
1767         return file->f_op->read_iter(kio, iter);
1768 }
1769 
1770 static inline ssize_t call_write_iter(struct file *file, struct kiocb *kio,
1771                                       struct iov_iter *iter)
1772 {
1773         return file->f_op->write_iter(kio, iter);
1774 }
1775 
1776 static inline int call_mmap(struct file *file, struct vm_area_struct *vma)
1777 {
1778         return file->f_op->mmap(file, vma);
1779 }
1780 
1781 ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector,
1782                               unsigned long nr_segs, unsigned long fast_segs,
1783                               struct iovec *fast_pointer,
1784                               struct iovec **ret_pointer);
1785 
1786 extern ssize_t __vfs_read(struct file *, char __user *, size_t, loff_t *);
1787 extern ssize_t vfs_read(struct file *, char __user *, size_t, loff_t *);
1788 extern ssize_t vfs_write(struct file *, const char __user *, size_t, loff_t *);
1789 extern ssize_t vfs_readv(struct file *, const struct iovec __user *,
1790                 unsigned long, loff_t *, rwf_t);
1791 extern ssize_t vfs_copy_file_range(struct file *, loff_t , struct file *,
1792                                    loff_t, size_t, unsigned int);
1793 extern int vfs_clone_file_prep_inodes(struct inode *inode_in, loff_t pos_in,
1794                                       struct inode *inode_out, loff_t pos_out,
1795                                       u64 *len, bool is_dedupe);
1796 extern int vfs_clone_file_range(struct file *file_in, loff_t pos_in,
1797                 struct file *file_out, loff_t pos_out, u64 len);
1798 extern int vfs_dedupe_file_range_compare(struct inode *src, loff_t srcoff,
1799                                          struct inode *dest, loff_t destoff,
1800                                          loff_t len, bool *is_same);
1801 extern int vfs_dedupe_file_range(struct file *file,
1802                                  struct file_dedupe_range *same);
1803 
1804 struct super_operations {
1805         struct inode *(*alloc_inode)(struct super_block *sb);
1806         void (*destroy_inode)(struct inode *);
1807 
1808         void (*dirty_inode) (struct inode *, int flags);
1809         int (*write_inode) (struct inode *, struct writeback_control *wbc);
1810         int (*drop_inode) (struct inode *);
1811         void (*evict_inode) (struct inode *);
1812         void (*put_super) (struct super_block *);
1813         int (*sync_fs)(struct super_block *sb, int wait);
1814         int (*freeze_super) (struct super_block *);
1815         int (*freeze_fs) (struct super_block *);
1816         int (*thaw_super) (struct super_block *);
1817         int (*unfreeze_fs) (struct super_block *);
1818         int (*statfs) (struct dentry *, struct kstatfs *);
1819         int (*remount_fs) (struct super_block *, int *, char *);
1820         void (*umount_begin) (struct super_block *);
1821 
1822         int (*show_options)(struct seq_file *, struct dentry *);
1823         int (*show_devname)(struct seq_file *, struct dentry *);
1824         int (*show_path)(struct seq_file *, struct dentry *);
1825         int (*show_stats)(struct seq_file *, struct dentry *);
1826 #ifdef CONFIG_QUOTA
1827         ssize_t (*quota_read)(struct super_block *, int, char *, size_t, loff_t);
1828         ssize_t (*quota_write)(struct super_block *, int, const char *, size_t, loff_t);
1829         struct dquot **(*get_dquots)(struct inode *);
1830 #endif
1831         int (*bdev_try_to_free_page)(struct super_block*, struct page*, gfp_t);
1832         long (*nr_cached_objects)(struct super_block *,
1833                                   struct shrink_control *);
1834         long (*free_cached_objects)(struct super_block *,
1835                                     struct shrink_control *);
1836 };
1837 
1838 /*
1839  * Inode flags - they have no relation to superblock flags now
1840  */
1841 #define S_SYNC          1       /* Writes are synced at once */
1842 #define S_NOATIME       2       /* Do not update access times */
1843 #define S_APPEND        4       /* Append-only file */
1844 #define S_IMMUTABLE     8       /* Immutable file */
1845 #define S_DEAD          16      /* removed, but still open directory */
1846 #define S_NOQUOTA       32      /* Inode is not counted to quota */
1847 #define S_DIRSYNC       64      /* Directory modifications are synchronous */
1848 #define S_NOCMTIME      128     /* Do not update file c/mtime */
1849 #define S_SWAPFILE      256     /* Do not truncate: swapon got its bmaps */
1850 #define S_PRIVATE       512     /* Inode is fs-internal */
1851 #define S_IMA           1024    /* Inode has an associated IMA struct */
1852 #define S_AUTOMOUNT     2048    /* Automount/referral quasi-directory */
1853 #define S_NOSEC         4096    /* no suid or xattr security attributes */
1854 #ifdef CONFIG_FS_DAX
1855 #define S_DAX           8192    /* Direct Access, avoiding the page cache */
1856 #else
1857 #define S_DAX           0       /* Make all the DAX code disappear */
1858 #endif
1859 #define S_ENCRYPTED     16384   /* Encrypted file (using fs/crypto/) */
1860 
1861 /*
1862  * Note that nosuid etc flags are inode-specific: setting some file-system
1863  * flags just means all the inodes inherit those flags by default. It might be
1864  * possible to override it selectively if you really wanted to with some
1865  * ioctl() that is not currently implemented.
1866  *
1867  * Exception: SB_RDONLY is always applied to the entire file system.
1868  *
1869  * Unfortunately, it is possible to change a filesystems flags with it mounted
1870  * with files in use.  This means that all of the inodes will not have their
1871  * i_flags updated.  Hence, i_flags no longer inherit the superblock mount
1872  * flags, so these have to be checked separately. -- rmk@arm.uk.linux.org
1873  */
1874 #define __IS_FLG(inode, flg)    ((inode)->i_sb->s_flags & (flg))
1875 
1876 static inline bool sb_rdonly(const struct super_block *sb) { return sb->s_flags & SB_RDONLY; }
1877 #define IS_RDONLY(inode)        sb_rdonly((inode)->i_sb)
1878 #define IS_SYNC(inode)          (__IS_FLG(inode, SB_SYNCHRONOUS) || \
1879                                         ((inode)->i_flags & S_SYNC))
1880 #define IS_DIRSYNC(inode)       (__IS_FLG(inode, SB_SYNCHRONOUS|SB_DIRSYNC) || \
1881                                         ((inode)->i_flags & (S_SYNC|S_DIRSYNC)))
1882 #define IS_MANDLOCK(inode)      __IS_FLG(inode, SB_MANDLOCK)
1883 #define IS_NOATIME(inode)       __IS_FLG(inode, SB_RDONLY|SB_NOATIME)
1884 #define IS_I_VERSION(inode)     __IS_FLG(inode, SB_I_VERSION)
1885 
1886 #define IS_NOQUOTA(inode)       ((inode)->i_flags & S_NOQUOTA)
1887 #define IS_APPEND(inode)        ((inode)->i_flags & S_APPEND)
1888 #define IS_IMMUTABLE(inode)     ((inode)->i_flags & S_IMMUTABLE)
1889 #define IS_POSIXACL(inode)      __IS_FLG(inode, SB_POSIXACL)
1890 
1891 #define IS_DEADDIR(inode)       ((inode)->i_flags & S_DEAD)
1892 #define IS_NOCMTIME(inode)      ((inode)->i_flags & S_NOCMTIME)
1893 #define IS_SWAPFILE(inode)      ((inode)->i_flags & S_SWAPFILE)
1894 #define IS_PRIVATE(inode)       ((inode)->i_flags & S_PRIVATE)
1895 #define IS_IMA(inode)           ((inode)->i_flags & S_IMA)
1896 #define IS_AUTOMOUNT(inode)     ((inode)->i_flags & S_AUTOMOUNT)
1897 #define IS_NOSEC(inode)         ((inode)->i_flags & S_NOSEC)
1898 #define IS_DAX(inode)           ((inode)->i_flags & S_DAX)
1899 #define IS_ENCRYPTED(inode)     ((inode)->i_flags & S_ENCRYPTED)
1900 
1901 #define IS_WHITEOUT(inode)      (S_ISCHR(inode->i_mode) && \
1902                                  (inode)->i_rdev == WHITEOUT_DEV)
1903 
1904 static inline bool HAS_UNMAPPED_ID(struct inode *inode)
1905 {
1906         return !uid_valid(inode->i_uid) || !gid_valid(inode->i_gid);
1907 }
1908 
1909 static inline enum rw_hint file_write_hint(struct file *file)
1910 {
1911         if (file->f_write_hint != WRITE_LIFE_NOT_SET)
1912                 return file->f_write_hint;
1913 
1914         return file_inode(file)->i_write_hint;
1915 }
1916 
1917 static inline int iocb_flags(struct file *file);
1918 
1919 static inline void init_sync_kiocb(struct kiocb *kiocb, struct file *filp)
1920 {
1921         *kiocb = (struct kiocb) {
1922                 .ki_filp = filp,
1923                 .ki_flags = iocb_flags(filp),
1924                 .ki_hint = file_write_hint(filp),
1925         };
1926 }
1927 
1928 /*
1929  * Inode state bits.  Protected by inode->i_lock
1930  *
1931  * Three bits determine the dirty state of the inode, I_DIRTY_SYNC,
1932  * I_DIRTY_DATASYNC and I_DIRTY_PAGES.
1933  *
1934  * Four bits define the lifetime of an inode.  Initially, inodes are I_NEW,
1935  * until that flag is cleared.  I_WILL_FREE, I_FREEING and I_CLEAR are set at
1936  * various stages of removing an inode.
1937  *
1938  * Two bits are used for locking and completion notification, I_NEW and I_SYNC.
1939  *
1940  * I_DIRTY_SYNC         Inode is dirty, but doesn't have to be written on
1941  *                      fdatasync().  i_atime is the usual cause.
1942  * I_DIRTY_DATASYNC     Data-related inode changes pending. We keep track of
1943  *                      these changes separately from I_DIRTY_SYNC so that we
1944  *                      don't have to write inode on fdatasync() when only
1945  *                      mtime has changed in it.
1946  * I_DIRTY_PAGES        Inode has dirty pages.  Inode itself may be clean.
1947  * I_NEW                Serves as both a mutex and completion notification.
1948  *                      New inodes set I_NEW.  If two processes both create
1949  *                      the same inode, one of them will release its inode and
1950  *                      wait for I_NEW to be released before returning.
1951  *                      Inodes in I_WILL_FREE, I_FREEING or I_CLEAR state can
1952  *                      also cause waiting on I_NEW, without I_NEW actually
1953  *                      being set.  find_inode() uses this to prevent returning
1954  *                      nearly-dead inodes.
1955  * I_WILL_FREE          Must be set when calling write_inode_now() if i_count
1956  *                      is zero.  I_FREEING must be set when I_WILL_FREE is
1957  *                      cleared.
1958  * I_FREEING            Set when inode is about to be freed but still has dirty
1959  *                      pages or buffers attached or the inode itself is still
1960  *                      dirty.
1961  * I_CLEAR              Added by clear_inode().  In this state the inode is
1962  *                      clean and can be destroyed.  Inode keeps I_FREEING.
1963  *
1964  *                      Inodes that are I_WILL_FREE, I_FREEING or I_CLEAR are
1965  *                      prohibited for many purposes.  iget() must wait for
1966  *                      the inode to be completely released, then create it
1967  *                      anew.  Other functions will just ignore such inodes,
1968  *                      if appropriate.  I_NEW is used for waiting.
1969  *
1970  * I_SYNC               Writeback of inode is running. The bit is set during
1971  *                      data writeback, and cleared with a wakeup on the bit
1972  *                      address once it is done. The bit is also used to pin
1973  *                      the inode in memory for flusher thread.
1974  *
1975  * I_REFERENCED         Marks the inode as recently references on the LRU list.
1976  *
1977  * I_DIO_WAKEUP         Never set.  Only used as a key for wait_on_bit().
1978  *
1979  * I_WB_SWITCH          Cgroup bdi_writeback switching in progress.  Used to
1980  *                      synchronize competing switching instances and to tell
1981  *                      wb stat updates to grab mapping->tree_lock.  See
1982  *                      inode_switch_wb_work_fn() for details.
1983  *
1984  * I_OVL_INUSE          Used by overlayfs to get exclusive ownership on upper
1985  *                      and work dirs among overlayfs mounts.
1986  *
1987  * Q: What is the difference between I_WILL_FREE and I_FREEING?
1988  */
1989 #define I_DIRTY_SYNC            (1 << 0)
1990 #define I_DIRTY_DATASYNC        (1 << 1)
1991 #define I_DIRTY_PAGES           (1 << 2)
1992 #define __I_NEW                 3
1993 #define I_NEW                   (1 << __I_NEW)
1994 #define I_WILL_FREE             (1 << 4)
1995 #define I_FREEING               (1 << 5)
1996 #define I_CLEAR                 (1 << 6)
1997 #define __I_SYNC                7
1998 #define I_SYNC                  (1 << __I_SYNC)
1999 #define I_REFERENCED            (1 << 8)
2000 #define __I_DIO_WAKEUP          9
2001 #define I_DIO_WAKEUP            (1 << __I_DIO_WAKEUP)
2002 #define I_LINKABLE              (1 << 10)
2003 #define I_DIRTY_TIME            (1 << 11)
2004 #define __I_DIRTY_TIME_EXPIRED  12
2005 #define I_DIRTY_TIME_EXPIRED    (1 << __I_DIRTY_TIME_EXPIRED)
2006 #define I_WB_SWITCH             (1 << 13)
2007 #define I_OVL_INUSE                     (1 << 14)
2008 
2009 #define I_DIRTY (I_DIRTY_SYNC | I_DIRTY_DATASYNC | I_DIRTY_PAGES)
2010 #define I_DIRTY_ALL (I_DIRTY | I_DIRTY_TIME)
2011 
2012 extern void __mark_inode_dirty(struct inode *, int);
2013 static inline void mark_inode_dirty(struct inode *inode)
2014 {
2015         __mark_inode_dirty(inode, I_DIRTY);
2016 }
2017 
2018 static inline void mark_inode_dirty_sync(struct inode *inode)
2019 {
2020         __mark_inode_dirty(inode, I_DIRTY_SYNC);
2021 }
2022 
2023 extern void inc_nlink(struct inode *inode);
2024 extern void drop_nlink(struct inode *inode);
2025 extern void clear_nlink(struct inode *inode);
2026 extern void set_nlink(struct inode *inode, unsigned int nlink);
2027 
2028 static inline void inode_inc_link_count(struct inode *inode)
2029 {
2030         inc_nlink(inode);
2031         mark_inode_dirty(inode);
2032 }
2033 
2034 static inline void inode_dec_link_count(struct inode *inode)
2035 {
2036         drop_nlink(inode);
2037         mark_inode_dirty(inode);
2038 }
2039 
2040 /**
2041  * inode_inc_iversion - increments i_version
2042  * @inode: inode that need to be updated
2043  *
2044  * Every time the inode is modified, the i_version field will be incremented.
2045  * The filesystem has to be mounted with i_version flag
2046  */
2047 
2048 static inline void inode_inc_iversion(struct inode *inode)
2049 {
2050        spin_lock(&inode->i_lock);
2051        inode->i_version++;
2052        spin_unlock(&inode->i_lock);
2053 }
2054 
2055 enum file_time_flags {
2056         S_ATIME = 1,
2057         S_MTIME = 2,
2058         S_CTIME = 4,
2059         S_VERSION = 8,
2060 };
2061 
2062 extern void touch_atime(const struct path *);
2063 static inline void file_accessed(struct file *file)
2064 {
2065         if (!(file->f_flags & O_NOATIME))
2066                 touch_atime(&file->f_path);
2067 }
2068 
2069 int sync_inode(struct inode *inode, struct writeback_control *wbc);
2070 int sync_inode_metadata(struct inode *inode, int wait);
2071 
2072 struct file_system_type {
2073         const char *name;
2074         int fs_flags;
2075 #define FS_REQUIRES_DEV         1 
2076 #define FS_BINARY_MOUNTDATA     2
2077 #define FS_HAS_SUBTYPE          4
2078 #define FS_USERNS_MOUNT         8       /* Can be mounted by userns root */
2079 #define FS_RENAME_DOES_D_MOVE   32768   /* FS will handle d_move() during rename() internally. */
2080         struct dentry *(*mount) (struct file_system_type *, int,
2081                        const char *, void *);
2082         void (*kill_sb) (struct super_block *);
2083         struct module *owner;
2084         struct file_system_type * next;
2085         struct hlist_head fs_supers;
2086 
2087         struct lock_class_key s_lock_key;
2088         struct lock_class_key s_umount_key;
2089         struct lock_class_key s_vfs_rename_key;
2090         struct lock_class_key s_writers_key[SB_FREEZE_LEVELS];
2091 
2092         struct lock_class_key i_lock_key;
2093         struct lock_class_key i_mutex_key;
2094         struct lock_class_key i_mutex_dir_key;
2095 };
2096 
2097 #define MODULE_ALIAS_FS(NAME) MODULE_ALIAS("fs-" NAME)
2098 
2099 extern struct dentry *mount_ns(struct file_system_type *fs_type,
2100         int flags, void *data, void *ns, struct user_namespace *user_ns,
2101         int (*fill_super)(struct super_block *, void *, int));
2102 #ifdef CONFIG_BLOCK
2103 extern struct dentry *mount_bdev(struct file_system_type *fs_type,
2104         int flags, const char *dev_name, void *data,
2105         int (*fill_super)(struct super_block *, void *, int));
2106 #else
2107 static inline struct dentry *mount_bdev(struct file_system_type *fs_type,
2108         int flags, const char *dev_name, void *data,
2109         int (*fill_super)(struct super_block *, void *, int))
2110 {
2111         return ERR_PTR(-ENODEV);
2112 }
2113 #endif
2114 extern struct dentry *mount_single(struct file_system_type *fs_type,
2115         int flags, void *data,
2116         int (*fill_super)(struct super_block *, void *, int));
2117 extern struct dentry *mount_nodev(struct file_system_type *fs_type,
2118         int flags, void *data,
2119         int (*fill_super)(struct super_block *, void *, int));
2120 extern struct dentry *mount_subtree(struct vfsmount *mnt, const char *path);
2121 void generic_shutdown_super(struct super_block *sb);
2122 #ifdef CONFIG_BLOCK
2123 void kill_block_super(struct super_block *sb);
2124 #else
2125 static inline void kill_block_super(struct super_block *sb)
2126 {
2127         BUG();
2128 }
2129 #endif
2130 void kill_anon_super(struct super_block *sb);
2131 void kill_litter_super(struct super_block *sb);
2132 void deactivate_super(struct super_block *sb);
2133 void deactivate_locked_super(struct super_block *sb);
2134 int set_anon_super(struct super_block *s, void *data);
2135 int get_anon_bdev(dev_t *);
2136 void free_anon_bdev(dev_t);
2137 struct super_block *sget_userns(struct file_system_type *type,
2138                         int (*test)(struct super_block *,void *),
2139                         int (*set)(struct super_block *,void *),
2140                         int flags, struct user_namespace *user_ns,
2141                         void *data);
2142 struct super_block *sget(struct file_system_type *type,
2143                         int (*test)(struct super_block *,void *),
2144                         int (*set)(struct super_block *,void *),
2145                         int flags, void *data);
2146 extern struct dentry *mount_pseudo_xattr(struct file_system_type *, char *,
2147                                          const struct super_operations *ops,
2148                                          const struct xattr_handler **xattr,
2149                                          const struct dentry_operations *dops,
2150                                          unsigned long);
2151 
2152 static inline struct dentry *
2153 mount_pseudo(struct file_system_type *fs_type, char *name,
2154              const struct super_operations *ops,
2155              const struct dentry_operations *dops, unsigned long magic)
2156 {
2157         return mount_pseudo_xattr(fs_type, name, ops, NULL, dops, magic);
2158 }
2159 
2160 /* Alas, no aliases. Too much hassle with bringing module.h everywhere */
2161 #define fops_get(fops) \
2162         (((fops) && try_module_get((fops)->owner) ? (fops) : NULL))
2163 #define fops_put(fops) \
2164         do { if (fops) module_put((fops)->owner); } while(0)
2165 /*
2166  * This one is to be used *ONLY* from ->open() instances.
2167  * fops must be non-NULL, pinned down *and* module dependencies
2168  * should be sufficient to pin the caller down as well.
2169  */
2170 #define replace_fops(f, fops) \
2171         do {    \
2172                 struct file *__file = (f); \
2173                 fops_put(__file->f_op); \
2174                 BUG_ON(!(__file->f_op = (fops))); \
2175         } while(0)
2176 
2177 extern int register_filesystem(struct file_system_type *);
2178 extern int unregister_filesystem(struct file_system_type *);
2179 extern struct vfsmount *kern_mount_data(struct file_system_type *, void *data);
2180 #define kern_mount(type) kern_mount_data(type, NULL)
2181 extern void kern_unmount(struct vfsmount *mnt);
2182 extern int may_umount_tree(struct vfsmount *);
2183 extern int may_umount(struct vfsmount *);
2184 extern long do_mount(const char *, const char __user *,
2185                      const char *, unsigned long, void *);
2186 extern struct vfsmount *collect_mounts(const struct path *);
2187 extern void drop_collected_mounts(struct vfsmount *);
2188 extern int iterate_mounts(int (*)(struct vfsmount *, void *), void *,
2189                           struct vfsmount *);
2190 extern int vfs_statfs(const struct path *, struct kstatfs *);
2191 extern int user_statfs(const char __user *, struct kstatfs *);
2192 extern int fd_statfs(int, struct kstatfs *);
2193 extern int freeze_super(struct super_block *super);
2194 extern int thaw_super(struct super_block *super);
2195 extern bool our_mnt(struct vfsmount *mnt);
2196 extern __printf(2, 3)
2197 int super_setup_bdi_name(struct super_block *sb, char *fmt, ...);
2198 extern int super_setup_bdi(struct super_block *sb);
2199 
2200 extern int current_umask(void);
2201 
2202 extern void ihold(struct inode * inode);
2203 extern void iput(struct inode *);
2204 extern int generic_update_time(struct inode *, struct timespec *, int);
2205 
2206 /* /sys/fs */
2207 extern struct kobject *fs_kobj;
2208 
2209 #define MAX_RW_COUNT (INT_MAX & PAGE_MASK)
2210 
2211 #ifdef CONFIG_MANDATORY_FILE_LOCKING
2212 extern int locks_mandatory_locked(struct file *);
2213 extern int locks_mandatory_area(struct inode *, struct file *, loff_t, loff_t, unsigned char);
2214 
2215 /*
2216  * Candidates for mandatory locking have the setgid bit set
2217  * but no group execute bit -  an otherwise meaningless combination.
2218  */
2219 
2220 static inline int __mandatory_lock(struct inode *ino)
2221 {
2222         return (ino->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID;
2223 }
2224 
2225 /*
2226  * ... and these candidates should be on SB_MANDLOCK mounted fs,
2227  * otherwise these will be advisory locks
2228  */
2229 
2230 static inline int mandatory_lock(struct inode *ino)
2231 {
2232         return IS_MANDLOCK(ino) && __mandatory_lock(ino);
2233 }
2234 
2235 static inline int locks_verify_locked(struct file *file)
2236 {
2237         if (mandatory_lock(locks_inode(file)))
2238                 return locks_mandatory_locked(file);
2239         return 0;
2240 }
2241 
2242 static inline int locks_verify_truncate(struct inode *inode,
2243                                     struct file *f,
2244                                     loff_t size)
2245 {
2246         if (!inode->i_flctx || !mandatory_lock(inode))
2247                 return 0;
2248 
2249         if (size < inode->i_size) {
2250                 return locks_mandatory_area(inode, f, size, inode->i_size - 1,
2251                                 F_WRLCK);
2252         } else {
2253                 return locks_mandatory_area(inode, f, inode->i_size, size - 1,
2254                                 F_WRLCK);
2255         }
2256 }
2257 
2258 #else /* !CONFIG_MANDATORY_FILE_LOCKING */
2259 
2260 static inline int locks_mandatory_locked(struct file *file)
2261 {
2262         return 0;
2263 }
2264 
2265 static inline int locks_mandatory_area(struct inode *inode, struct file *filp,
2266                                        loff_t start, loff_t end, unsigned char type)
2267 {
2268         return 0;
2269 }
2270 
2271 static inline int __mandatory_lock(struct inode *inode)
2272 {
2273         return 0;
2274 }
2275 
2276 static inline int mandatory_lock(struct inode *inode)
2277 {
2278         return 0;
2279 }
2280 
2281 static inline int locks_verify_locked(struct file *file)
2282 {
2283         return 0;
2284 }
2285 
2286 static inline int locks_verify_truncate(struct inode *inode, struct file *filp,
2287                                         size_t size)
2288 {
2289         return 0;
2290 }
2291 
2292 #endif /* CONFIG_MANDATORY_FILE_LOCKING */
2293 
2294 
2295 #ifdef CONFIG_FILE_LOCKING
2296 static inline int break_lease(struct inode *inode, unsigned int mode)
2297 {
2298         /*
2299          * Since this check is lockless, we must ensure that any refcounts
2300          * taken are done before checking i_flctx->flc_lease. Otherwise, we
2301          * could end up racing with tasks trying to set a new lease on this
2302          * file.
2303          */
2304         smp_mb();
2305         if (inode->i_flctx && !list_empty_careful(&inode->i_flctx->flc_lease))
2306                 return __break_lease(inode, mode, FL_LEASE);
2307         return 0;
2308 }
2309 
2310 static inline int break_deleg(struct inode *inode, unsigned int mode)
2311 {
2312         /*
2313          * Since this check is lockless, we must ensure that any refcounts
2314          * taken are done before checking i_flctx->flc_lease. Otherwise, we
2315          * could end up racing with tasks trying to set a new lease on this
2316          * file.
2317          */
2318         smp_mb();
2319         if (inode->i_flctx && !list_empty_careful(&inode->i_flctx->flc_lease))
2320                 return __break_lease(inode, mode, FL_DELEG);
2321         return 0;
2322 }
2323 
2324 static inline int try_break_deleg(struct inode *inode, struct inode **delegated_inode)
2325 {
2326         int ret;
2327 
2328         ret = break_deleg(inode, O_WRONLY|O_NONBLOCK);
2329         if (ret == -EWOULDBLOCK && delegated_inode) {
2330                 *delegated_inode = inode;
2331                 ihold(inode);
2332         }
2333         return ret;
2334 }
2335 
2336 static inline int break_deleg_wait(struct inode **delegated_inode)
2337 {
2338         int ret;
2339 
2340         ret = break_deleg(*delegated_inode, O_WRONLY);
2341         iput(*delegated_inode);
2342         *delegated_inode = NULL;
2343         return ret;
2344 }
2345 
2346 static inline int break_layout(struct inode *inode, bool wait)
2347 {
2348         smp_mb();
2349         if (inode->i_flctx && !list_empty_careful(&inode->i_flctx->flc_lease))
2350                 return __break_lease(inode,
2351                                 wait ? O_WRONLY : O_WRONLY | O_NONBLOCK,
2352                                 FL_LAYOUT);
2353         return 0;
2354 }
2355 
2356 #else /* !CONFIG_FILE_LOCKING */
2357 static inline int break_lease(struct inode *inode, unsigned int mode)
2358 {
2359         return 0;
2360 }
2361 
2362 static inline int break_deleg(struct inode *inode, unsigned int mode)
2363 {
2364         return 0;
2365 }
2366 
2367 static inline int try_break_deleg(struct inode *inode, struct inode **delegated_inode)
2368 {
2369         return 0;
2370 }
2371 
2372 static inline int break_deleg_wait(struct inode **delegated_inode)
2373 {
2374         BUG();
2375         return 0;
2376 }
2377 
2378 static inline int break_layout(struct inode *inode, bool wait)
2379 {
2380         return 0;
2381 }
2382 
2383 #endif /* CONFIG_FILE_LOCKING */
2384 
2385 /* fs/open.c */
2386 struct audit_names;
2387 struct filename {
2388         const char              *name;  /* pointer to actual string */
2389         const __user char       *uptr;  /* original userland pointer */
2390         struct audit_names      *aname;
2391         int                     refcnt;
2392         const char              iname[];
2393 };
2394 
2395 extern long vfs_truncate(const struct path *, loff_t);
2396 extern int do_truncate(struct dentry *, loff_t start, unsigned int time_attrs,
2397                        struct file *filp);
2398 extern int vfs_fallocate(struct file *file, int mode, loff_t offset,
2399                         loff_t len);
2400 extern long do_sys_open(int dfd, const char __user *filename, int flags,
2401                         umode_t mode);
2402 extern struct file *file_open_name(struct filename *, int, umode_t);
2403 extern struct file *filp_open(const char *, int, umode_t);
2404 extern struct file *file_open_root(struct dentry *, struct vfsmount *,
2405                                    const char *, int, umode_t);
2406 extern struct file * dentry_open(const struct path *, int, const struct cred *);
2407 extern int filp_close(struct file *, fl_owner_t id);
2408 
2409 extern struct filename *getname_flags(const char __user *, int, int *);
2410 extern struct filename *getname(const char __user *);
2411 extern struct filename *getname_kernel(const char *);
2412 extern void putname(struct filename *name);
2413 
2414 enum {
2415         FILE_CREATED = 1,
2416         FILE_OPENED = 2
2417 };
2418 extern int finish_open(struct file *file, struct dentry *dentry,
2419                         int (*open)(struct inode *, struct file *),
2420                         int *opened);
2421 extern int finish_no_open(struct file *file, struct dentry *dentry);
2422 
2423 /* fs/ioctl.c */
2424 
2425 extern int ioctl_preallocate(struct file *filp, void __user *argp);
2426 
2427 /* fs/dcache.c */
2428 extern void __init vfs_caches_init_early(void);
2429 extern void __init vfs_caches_init(void);
2430 
2431 extern struct kmem_cache *names_cachep;
2432 
2433 #define __getname()             kmem_cache_alloc(names_cachep, GFP_KERNEL)
2434 #define __putname(name)         kmem_cache_free(names_cachep, (void *)(name))
2435 
2436 #ifdef CONFIG_BLOCK
2437 extern int register_blkdev(unsigned int, const char *);
2438 extern void unregister_blkdev(unsigned int, const char *);
2439 extern void bdev_unhash_inode(dev_t dev);
2440 extern struct block_device *bdget(dev_t);
2441 extern struct block_device *bdgrab(struct block_device *bdev);
2442 extern void bd_set_size(struct block_device *, loff_t size);
2443 extern void bd_forget(struct inode *inode);
2444 extern void bdput(struct block_device *);
2445 extern void invalidate_bdev(struct block_device *);
2446 extern void iterate_bdevs(void (*)(struct block_device *, void *), void *);
2447 extern int sync_blockdev(struct block_device *bdev);
2448 extern void kill_bdev(struct block_device *);
2449 extern struct super_block *freeze_bdev(struct block_device *);
2450 extern void emergency_thaw_all(void);
2451 extern int thaw_bdev(struct block_device *bdev, struct super_block *sb);
2452 extern int fsync_bdev(struct block_device *);
2453 
2454 extern struct super_block *blockdev_superblock;
2455 
2456 static inline bool sb_is_blkdev_sb(struct super_block *sb)
2457 {
2458         return sb == blockdev_superblock;
2459 }
2460 #else
2461 static inline void bd_forget(struct inode *inode) {}
2462 static inline int sync_blockdev(struct block_device *bdev) { return 0; }
2463 static inline void kill_bdev(struct block_device *bdev) {}
2464 static inline void invalidate_bdev(struct block_device *bdev) {}
2465 
2466 static inline struct super_block *freeze_bdev(struct block_device *sb)
2467 {
2468         return NULL;
2469 }
2470 
2471 static inline int thaw_bdev(struct block_device *bdev, struct super_block *sb)
2472 {
2473         return 0;
2474 }
2475 
2476 static inline void iterate_bdevs(void (*f)(struct block_device *, void *), void *arg)
2477 {
2478 }
2479 
2480 static inline bool sb_is_blkdev_sb(struct super_block *sb)
2481 {
2482         return false;
2483 }
2484 #endif
2485 extern int sync_filesystem(struct super_block *);
2486 extern const struct file_operations def_blk_fops;
2487 extern const struct file_operations def_chr_fops;
2488 #ifdef CONFIG_BLOCK
2489 extern int ioctl_by_bdev(struct block_device *, unsigned, unsigned long);
2490 extern int blkdev_ioctl(struct block_device *, fmode_t, unsigned, unsigned long);
2491 extern long compat_blkdev_ioctl(struct file *, unsigned, unsigned long);
2492 extern int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder);
2493 extern struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
2494                                                void *holder);
2495 extern struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode,
2496                                               void *holder);
2497 extern void blkdev_put(struct block_device *bdev, fmode_t mode);
2498 extern int __blkdev_reread_part(struct block_device *bdev);
2499 extern int blkdev_reread_part(struct block_device *bdev);
2500 
2501 #ifdef CONFIG_SYSFS
2502 extern int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk);
2503 extern void bd_unlink_disk_holder(struct block_device *bdev,
2504                                   struct gendisk *disk);
2505 #else
2506 static inline int bd_link_disk_holder(struct block_device *bdev,
2507                                       struct gendisk *disk)
2508 {
2509         return 0;
2510 }
2511 static inline void bd_unlink_disk_holder(struct block_device *bdev,
2512                                          struct gendisk *disk)
2513 {
2514 }
2515 #endif
2516 #endif
2517 
2518 /* fs/char_dev.c */
2519 #define CHRDEV_MAJOR_MAX 512
2520 /* Marks the bottom of the first segment of free char majors */
2521 #define CHRDEV_MAJOR_DYN_END 234
2522 /* Marks the top and bottom of the second segment of free char majors */
2523 #define CHRDEV_MAJOR_DYN_EXT_START 511
2524 #define CHRDEV_MAJOR_DYN_EXT_END 384
2525 
2526 extern int alloc_chrdev_region(dev_t *, unsigned, unsigned, const char *);
2527 extern int register_chrdev_region(dev_t, unsigned, const char *);
2528 extern int __register_chrdev(unsigned int major, unsigned int baseminor,
2529                              unsigned int count, const char *name,
2530                              const struct file_operations *fops);
2531 extern void __unregister_chrdev(unsigned int major, unsigned int baseminor,
2532                                 unsigned int count, const char *name);
2533 extern void unregister_chrdev_region(dev_t, unsigned);
2534 extern void chrdev_show(struct seq_file *,off_t);
2535 
2536 static inline int register_chrdev(unsigned int major, const char *name,
2537                                   const struct file_operations *fops)
2538 {
2539         return __register_chrdev(major, 0, 256, name, fops);
2540 }
2541 
2542 static inline void unregister_chrdev(unsigned int major, const char *name)
2543 {
2544         __unregister_chrdev(major, 0, 256, name);
2545 }
2546 
2547 /* fs/block_dev.c */
2548 #define BDEVNAME_SIZE   32      /* Largest string for a blockdev identifier */
2549 #define BDEVT_SIZE      10      /* Largest string for MAJ:MIN for blkdev */
2550 
2551 #ifdef CONFIG_BLOCK
2552 #define BLKDEV_MAJOR_MAX        512
2553 extern const char *__bdevname(dev_t, char *buffer);
2554 extern const char *bdevname(struct block_device *bdev, char *buffer);
2555 extern struct block_device *lookup_bdev(const char *);
2556 extern void blkdev_show(struct seq_file *,off_t);
2557 
2558 #else
2559 #define BLKDEV_MAJOR_MAX        0
2560 #endif
2561 
2562 extern void init_special_inode(struct inode *, umode_t, dev_t);
2563 
2564 /* Invalid inode operations -- fs/bad_inode.c */
2565 extern void make_bad_inode(struct inode *);
2566 extern bool is_bad_inode(struct inode *);
2567 
2568 #ifdef CONFIG_BLOCK
2569 extern void check_disk_size_change(struct gendisk *disk,
2570                                    struct block_device *bdev);
2571 extern int revalidate_disk(struct gendisk *);
2572 extern int check_disk_change(struct block_device *);
2573 extern int __invalidate_device(struct block_device *, bool);
2574 extern int invalidate_partition(struct gendisk *, int);
2575 #endif
2576 unsigned long invalidate_mapping_pages(struct address_space *mapping,
2577                                         pgoff_t start, pgoff_t end);
2578 
2579 static inline void invalidate_remote_inode(struct inode *inode)
2580 {
2581         if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
2582             S_ISLNK(inode->i_mode))
2583                 invalidate_mapping_pages(inode->i_mapping, 0, -1);
2584 }
2585 extern int invalidate_inode_pages2(struct address_space *mapping);
2586 extern int invalidate_inode_pages2_range(struct address_space *mapping,
2587                                          pgoff_t start, pgoff_t end);
2588 extern int write_inode_now(struct inode *, int);
2589 extern int filemap_fdatawrite(struct address_space *);
2590 extern int filemap_flush(struct address_space *);
2591 extern int filemap_fdatawait_keep_errors(struct address_space *mapping);
2592 extern int filemap_fdatawait_range(struct address_space *, loff_t lstart,
2593                                    loff_t lend);
2594 
2595 static inline int filemap_fdatawait(struct address_space *mapping)
2596 {
2597         return filemap_fdatawait_range(mapping, 0, LLONG_MAX);
2598 }
2599 
2600 extern bool filemap_range_has_page(struct address_space *, loff_t lstart,
2601                                   loff_t lend);
2602 extern int __must_check file_fdatawait_range(struct file *file, loff_t lstart,
2603                                                 loff_t lend);
2604 extern int filemap_write_and_wait(struct address_space *mapping);
2605 extern int filemap_write_and_wait_range(struct address_space *mapping,
2606                                         loff_t lstart, loff_t lend);
2607 extern int __filemap_fdatawrite_range(struct address_space *mapping,
2608                                 loff_t start, loff_t end, int sync_mode);
2609 extern int filemap_fdatawrite_range(struct address_space *mapping,
2610                                 loff_t start, loff_t end);
2611 extern int filemap_check_errors(struct address_space *mapping);
2612 extern void __filemap_set_wb_err(struct address_space *mapping, int err);
2613 
2614 extern int __must_check file_fdatawait_range(struct file *file, loff_t lstart,
2615                                                 loff_t lend);
2616 extern int __must_check file_check_and_advance_wb_err(struct file *file);
2617 extern int __must_check file_write_and_wait_range(struct file *file,
2618                                                 loff_t start, loff_t end);
2619 
2620 static inline int file_write_and_wait(struct file *file)
2621 {
2622         return file_write_and_wait_range(file, 0, LLONG_MAX);
2623 }
2624 
2625 /**
2626  * filemap_set_wb_err - set a writeback error on an address_space
2627  * @mapping: mapping in which to set writeback error
2628  * @err: error to be set in mapping
2629  *
2630  * When writeback fails in some way, we must record that error so that
2631  * userspace can be informed when fsync and the like are called.  We endeavor
2632  * to report errors on any file that was open at the time of the error.  Some
2633  * internal callers also need to know when writeback errors have occurred.
2634  *
2635  * When a writeback error occurs, most filesystems will want to call
2636  * filemap_set_wb_err to record the error in the mapping so that it will be
2637  * automatically reported whenever fsync is called on the file.
2638  */
2639 static inline void filemap_set_wb_err(struct address_space *mapping, int err)
2640 {
2641         /* Fastpath for common case of no error */
2642         if (unlikely(err))
2643                 __filemap_set_wb_err(mapping, err);
2644 }
2645 
2646 /**
2647  * filemap_check_wb_error - has an error occurred since the mark was sampled?
2648  * @mapping: mapping to check for writeback errors
2649  * @since: previously-sampled errseq_t
2650  *
2651  * Grab the errseq_t value from the mapping, and see if it has changed "since"
2652  * the given value was sampled.
2653  *
2654  * If it has then report the latest error set, otherwise return 0.
2655  */
2656 static inline int filemap_check_wb_err(struct address_space *mapping,
2657                                         errseq_t since)
2658 {
2659         return errseq_check(&mapping->wb_err, since);
2660 }
2661 
2662 /**
2663  * filemap_sample_wb_err - sample the current errseq_t to test for later errors
2664  * @mapping: mapping to be sampled
2665  *
2666  * Writeback errors are always reported relative to a particular sample point
2667  * in the past. This function provides those sample points.
2668  */
2669 static inline errseq_t filemap_sample_wb_err(struct address_space *mapping)
2670 {
2671         return errseq_sample(&mapping->wb_err);
2672 }
2673 
2674 extern int vfs_fsync_range(struct file *file, loff_t start, loff_t end,
2675                            int datasync);
2676 extern int vfs_fsync(struct file *file, int datasync);
2677 
2678 /*
2679  * Sync the bytes written if this was a synchronous write.  Expect ki_pos
2680  * to already be updated for the write, and will return either the amount
2681  * of bytes passed in, or an error if syncing the file failed.
2682  */
2683 static inline ssize_t generic_write_sync(struct kiocb *iocb, ssize_t count)
2684 {
2685         if (iocb->ki_flags & IOCB_DSYNC) {
2686                 int ret = vfs_fsync_range(iocb->ki_filp,
2687                                 iocb->ki_pos - count, iocb->ki_pos - 1,
2688                                 (iocb->ki_flags & IOCB_SYNC) ? 0 : 1);
2689                 if (ret)
2690                         return ret;
2691         }
2692 
2693         return count;
2694 }
2695 
2696 extern void emergency_sync(void);
2697 extern void emergency_remount(void);
2698 #ifdef CONFIG_BLOCK
2699 extern sector_t bmap(struct inode *, sector_t);
2700 #endif
2701 extern int notify_change(struct dentry *, struct iattr *, struct inode **);
2702 extern int inode_permission(struct inode *, int);
2703 extern int __inode_permission(struct inode *, int);
2704 extern int generic_permission(struct inode *, int);
2705 extern int __check_sticky(struct inode *dir, struct inode *inode);
2706 
2707 static inline bool execute_ok(struct inode *inode)
2708 {
2709         return (inode->i_mode & S_IXUGO) || S_ISDIR(inode->i_mode);
2710 }
2711 
2712 static inline void file_start_write(struct file *file)
2713 {
2714         if (!S_ISREG(file_inode(file)->i_mode))
2715                 return;
2716         __sb_start_write(file_inode(file)->i_sb, SB_FREEZE_WRITE, true);
2717 }
2718 
2719 static inline bool file_start_write_trylock(struct file *file)
2720 {
2721         if (!S_ISREG(file_inode(file)->i_mode))
2722                 return true;
2723         return __sb_start_write(file_inode(file)->i_sb, SB_FREEZE_WRITE, false);
2724 }
2725 
2726 static inline void file_end_write(struct file *file)
2727 {
2728         if (!S_ISREG(file_inode(file)->i_mode))
2729                 return;
2730         __sb_end_write(file_inode(file)->i_sb, SB_FREEZE_WRITE);
2731 }
2732 
2733 static inline int do_clone_file_range(struct file *file_in, loff_t pos_in,
2734                                       struct file *file_out, loff_t pos_out,
2735                                       u64 len)
2736 {
2737         int ret;
2738 
2739         file_start_write(file_out);
2740         ret = vfs_clone_file_range(file_in, pos_in, file_out, pos_out, len);
2741         file_end_write(file_out);
2742 
2743         return ret;
2744 }
2745 
2746 /*
2747  * get_write_access() gets write permission for a file.
2748  * put_write_access() releases this write permission.
2749  * This is used for regular files.
2750  * We cannot support write (and maybe mmap read-write shared) accesses and
2751  * MAP_DENYWRITE mmappings simultaneously. The i_writecount field of an inode
2752  * can have the following values:
2753  * 0: no writers, no VM_DENYWRITE mappings
2754  * < 0: (-i_writecount) vm_area_structs with VM_DENYWRITE set exist
2755  * > 0: (i_writecount) users are writing to the file.
2756  *
2757  * Normally we operate on that counter with atomic_{inc,dec} and it's safe
2758  * except for the cases where we don't hold i_writecount yet. Then we need to
2759  * use {get,deny}_write_access() - these functions check the sign and refuse
2760  * to do the change if sign is wrong.
2761  */
2762 static inline int get_write_access(struct inode *inode)
2763 {
2764         return atomic_inc_unless_negative(&inode->i_writecount) ? 0 : -ETXTBSY;
2765 }
2766 static inline int deny_write_access(struct file *file)
2767 {
2768         struct inode *inode = file_inode(file);
2769         return atomic_dec_unless_positive(&inode->i_writecount) ? 0 : -ETXTBSY;
2770 }
2771 static inline void put_write_access(struct inode * inode)
2772 {
2773         atomic_dec(&inode->i_writecount);
2774 }
2775 static inline void allow_write_access(struct file *file)
2776 {
2777         if (file)
2778                 atomic_inc(&file_inode(file)->i_writecount);
2779 }
2780 static inline bool inode_is_open_for_write(const struct inode *inode)
2781 {
2782         return atomic_read(&inode->i_writecount) > 0;
2783 }
2784 
2785 #ifdef CONFIG_IMA
2786 static inline void i_readcount_dec(struct inode *inode)
2787 {
2788         BUG_ON(!atomic_read(&inode->i_readcount));
2789         atomic_dec(&inode->i_readcount);
2790 }
2791 static inline void i_readcount_inc(struct inode *inode)
2792 {
2793         atomic_inc(&inode->i_readcount);
2794 }
2795 #else
2796 static inline void i_readcount_dec(struct inode *inode)
2797 {
2798         return;
2799 }
2800 static inline void i_readcount_inc(struct inode *inode)
2801 {
2802         return;
2803 }
2804 #endif
2805 extern int do_pipe_flags(int *, int);
2806 
2807 #define __kernel_read_file_id(id) \
2808         id(UNKNOWN, unknown)            \
2809         id(FIRMWARE, firmware)          \
2810         id(FIRMWARE_PREALLOC_BUFFER, firmware)  \
2811         id(MODULE, kernel-module)               \
2812         id(KEXEC_IMAGE, kexec-image)            \
2813         id(KEXEC_INITRAMFS, kexec-initramfs)    \
2814         id(POLICY, security-policy)             \
2815         id(X509_CERTIFICATE, x509-certificate)  \
2816         id(MAX_ID, )
2817 
2818 #define __fid_enumify(ENUM, dummy) READING_ ## ENUM,
2819 #define __fid_stringify(dummy, str) #str,
2820 
2821 enum kernel_read_file_id {
2822         __kernel_read_file_id(__fid_enumify)
2823 };
2824 
2825 static const char * const kernel_read_file_str[] = {
2826         __kernel_read_file_id(__fid_stringify)
2827 };
2828 
2829 static inline const char *kernel_read_file_id_str(enum kernel_read_file_id id)
2830 {
2831         if ((unsigned)id >= READING_MAX_ID)
2832                 return kernel_read_file_str[READING_UNKNOWN];
2833 
2834         return kernel_read_file_str[id];
2835 }
2836 
2837 extern int kernel_read_file(struct file *, void **, loff_t *, loff_t,
2838                             enum kernel_read_file_id);
2839 extern int kernel_read_file_from_path(const char *, void **, loff_t *, loff_t,
2840                                       enum kernel_read_file_id);
2841 extern int kernel_read_file_from_fd(int, void **, loff_t *, loff_t,
2842                                     enum kernel_read_file_id);
2843 extern ssize_t kernel_read(struct file *, void *, size_t, loff_t *);
2844 extern ssize_t kernel_write(struct file *, const void *, size_t, loff_t *);
2845 extern ssize_t __kernel_write(struct file *, const void *, size_t, loff_t *);
2846 extern struct file * open_exec(const char *);
2847  
2848 /* fs/dcache.c -- generic fs support functions */
2849 extern bool is_subdir(struct dentry *, struct dentry *);
2850 extern bool path_is_under(const struct path *, const struct path *);
2851 
2852 extern char *file_path(struct file *, char *, int);
2853 
2854 #include <linux/err.h>
2855 
2856 /* needed for stackable file system support */
2857 extern loff_t default_llseek(struct file *file, loff_t offset, int whence);
2858 
2859 extern loff_t vfs_llseek(struct file *file, loff_t offset, int whence);
2860 
2861 extern int inode_init_always(struct super_block *, struct inode *);
2862 extern void inode_init_once(struct inode *);
2863 extern void address_space_init_once(struct address_space *mapping);
2864 extern struct inode * igrab(struct inode *);
2865 extern ino_t iunique(struct super_block *, ino_t);
2866 extern int inode_needs_sync(struct inode *inode);
2867 extern int generic_delete_inode(struct inode *inode);
2868 static inline int generic_drop_inode(struct inode *inode)
2869 {
2870         return !inode->i_nlink || inode_unhashed(inode);
2871 }
2872 
2873 extern struct inode *ilookup5_nowait(struct super_block *sb,
2874                 unsigned long hashval, int (*test)(struct inode *, void *),
2875                 void *data);
2876 extern struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
2877                 int (*test)(struct inode *, void *), void *data);
2878 extern struct inode *ilookup(struct super_block *sb, unsigned long ino);
2879 
2880 extern struct inode * iget5_locked(struct super_block *, unsigned long, int (*test)(struct inode *, void *), int (*set)(struct inode *, void *), void *);
2881 extern struct inode * iget_locked(struct super_block *, unsigned long);
2882 extern struct inode *find_inode_nowait(struct super_block *,
2883                                        unsigned long,
2884                                        int (*match)(struct inode *,
2885                                                     unsigned long, void *),
2886                                        void *data);
2887 extern int insert_inode_locked4(struct inode *, unsigned long, int (*test)(struct inode *, void *), void *);
2888 extern int insert_inode_locked(struct inode *);
2889 #ifdef CONFIG_DEBUG_LOCK_ALLOC
2890 extern void lockdep_annotate_inode_mutex_key(struct inode *inode);
2891 #else
2892 static inline void lockdep_annotate_inode_mutex_key(struct inode *inode) { };
2893 #endif
2894 extern void unlock_new_inode(struct inode *);
2895 extern unsigned int get_next_ino(void);
2896 extern void evict_inodes(struct super_block *sb);
2897 
2898 extern void __iget(struct inode * inode);
2899 extern void iget_failed(struct inode *);
2900 extern void clear_inode(struct inode *);
2901 extern void __destroy_inode(struct inode *);
2902 extern struct inode *new_inode_pseudo(struct super_block *sb);
2903 extern struct inode *new_inode(struct super_block *sb);
2904 extern void free_inode_nonrcu(struct inode *inode);
2905 extern int should_remove_suid(struct dentry *);
2906 extern int file_remove_privs(struct file *);
2907 
2908 extern void __insert_inode_hash(struct inode *, unsigned long hashval);
2909 static inline void insert_inode_hash(struct inode *inode)
2910 {
2911         __insert_inode_hash(inode, inode->i_ino);
2912 }
2913 
2914 extern void __remove_inode_hash(struct inode *);
2915 static inline void remove_inode_hash(struct inode *inode)
2916 {
2917         if (!inode_unhashed(inode) && !hlist_fake(&inode->i_hash))
2918                 __remove_inode_hash(inode);
2919 }
2920 
2921 extern void inode_sb_list_add(struct inode *inode);
2922 
2923 #ifdef CONFIG_BLOCK
2924 extern int bdev_read_only(struct block_device *);
2925 #endif
2926 extern int set_blocksize(struct block_device *, int);
2927 extern int sb_set_blocksize(struct super_block *, int);
2928 extern int sb_min_blocksize(struct super_block *, int);
2929 
2930 extern int generic_file_mmap(struct file *, struct vm_area_struct *);
2931 extern int generic_file_readonly_mmap(struct file *, struct vm_area_struct *);
2932 extern ssize_t generic_write_checks(struct kiocb *, struct iov_iter *);
2933 extern ssize_t generic_file_read_iter(struct kiocb *, struct iov_iter *);
2934 extern ssize_t __generic_file_write_iter(struct kiocb *, struct iov_iter *);
2935 extern ssize_t generic_file_write_iter(struct kiocb *, struct iov_iter *);
2936 extern ssize_t generic_file_direct_write(struct kiocb *, struct iov_iter *);
2937 extern ssize_t generic_perform_write(struct file *, struct iov_iter *, loff_t);
2938 
2939 ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos,
2940                 rwf_t flags);
2941 ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos,
2942                 rwf_t flags);
2943 
2944 /* fs/block_dev.c */
2945 extern ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to);
2946 extern ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from);
2947 extern int blkdev_fsync(struct file *filp, loff_t start, loff_t end,
2948                         int datasync);
2949 extern void block_sync_page(struct page *page);
2950 
2951 /* fs/splice.c */
2952 extern ssize_t generic_file_splice_read(struct file *, loff_t *,
2953                 struct pipe_inode_info *, size_t, unsigned int);
2954 extern ssize_t iter_file_splice_write(struct pipe_inode_info *,
2955                 struct file *, loff_t *, size_t, unsigned int);
2956 extern ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe,
2957                 struct file *out, loff_t *, size_t len, unsigned int flags);
2958 extern long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
2959                 loff_t *opos, size_t len, unsigned int flags);
2960 
2961 
2962 extern void
2963 file_ra_state_init(struct file_ra_state *ra, struct address_space *mapping);
2964 extern loff_t noop_llseek(struct file *file, loff_t offset, int whence);
2965 extern loff_t no_llseek(struct file *file, loff_t offset, int whence);
2966 extern loff_t vfs_setpos(struct file *file, loff_t offset, loff_t maxsize);
2967 extern loff_t generic_file_llseek(struct file *file, loff_t offset, int whence);
2968 extern loff_t generic_file_llseek_size(struct file *file, loff_t offset,
2969                 int whence, loff_t maxsize, loff_t eof);
2970 extern loff_t fixed_size_llseek(struct file *file, loff_t offset,
2971                 int whence, loff_t size);
2972 extern loff_t no_seek_end_llseek_size(struct file *, loff_t, int, loff_t);
2973 extern loff_t no_seek_end_llseek(struct file *, loff_t, int);
2974 extern int generic_file_open(struct inode * inode, struct file * filp);
2975 extern int nonseekable_open(struct inode * inode, struct file * filp);
2976 
2977 #ifdef CONFIG_BLOCK
2978 typedef void (dio_submit_t)(struct bio *bio, struct inode *inode,
2979                             loff_t file_offset);
2980 
2981 enum {
2982         /* need locking between buffered and direct access */
2983         DIO_LOCKING     = 0x01,
2984 
2985         /* filesystem does not support filling holes */
2986         DIO_SKIP_HOLES  = 0x02,
2987 
2988         /* filesystem can handle aio writes beyond i_size */
2989         DIO_ASYNC_EXTEND = 0x04,
2990 
2991         /* inode/fs/bdev does not need truncate protection */
2992         DIO_SKIP_DIO_COUNT = 0x08,
2993 };
2994 
2995 void dio_end_io(struct bio *bio);
2996 
2997 ssize_t __blockdev_direct_IO(struct kiocb *iocb, struct inode *inode,
2998                              struct block_device *bdev, struct iov_iter *iter,
2999                              get_block_t get_block,
3000                              dio_iodone_t end_io, dio_submit_t submit_io,
3001                              int flags);
3002 
3003 static inline ssize_t blockdev_direct_IO(struct kiocb *iocb,
3004                                          struct inode *inode,
3005                                          struct iov_iter *iter,
3006                                          get_block_t get_block)
3007 {
3008         return __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev, iter,
3009                         get_block, NULL, NULL, DIO_LOCKING | DIO_SKIP_HOLES);
3010 }
3011 #endif
3012 
3013 void inode_dio_wait(struct inode *inode);
3014 
3015 /*
3016  * inode_dio_begin - signal start of a direct I/O requests
3017  * @inode: inode the direct I/O happens on
3018  *
3019  * This is called once we've finished processing a direct I/O request,
3020  * and is used to wake up callers waiting for direct I/O to be quiesced.
3021  */
3022 static inline void inode_dio_begin(struct inode *inode)
3023 {
3024         atomic_inc(&inode->i_dio_count);
3025 }
3026 
3027 /*
3028  * inode_dio_end - signal finish of a direct I/O requests
3029  * @inode: inode the direct I/O happens on
3030  *
3031  * This is called once we've finished processing a direct I/O request,
3032  * and is used to wake up callers waiting for direct I/O to be quiesced.
3033  */
3034 static inline void inode_dio_end(struct inode *inode)
3035 {
3036         if (atomic_dec_and_test(&inode->i_dio_count))
3037                 wake_up_bit(&inode->i_state, __I_DIO_WAKEUP);
3038 }
3039 
3040 extern void inode_set_flags(struct inode *inode, unsigned int flags,
3041                             unsigned int mask);
3042 
3043 extern const struct file_operations generic_ro_fops;
3044 
3045 #define special_file(m) (S_ISCHR(m)||S_ISBLK(m)||S_ISFIFO(m)||S_ISSOCK(m))
3046 
3047 extern int readlink_copy(char __user *, int, const char *);
3048 extern int page_readlink(struct dentry *, char __user *, int);
3049 extern const char *page_get_link(struct dentry *, struct inode *,
3050                                  struct delayed_call *);
3051 extern void page_put_link(void *);
3052 extern int __page_symlink(struct inode *inode, const char *symname, int len,
3053                 int nofs);
3054 extern int page_symlink(struct inode *inode, const char *symname, int len);
3055 extern const struct inode_operations page_symlink_inode_operations;
3056 extern void kfree_link(void *);
3057 extern void generic_fillattr(struct inode *, struct kstat *);
3058 extern int vfs_getattr_nosec(const struct path *, struct kstat *, u32, unsigned int);
3059 extern int vfs_getattr(const struct path *, struct kstat *, u32, unsigned int);
3060 void __inode_add_bytes(struct inode *inode, loff_t bytes);
3061 void inode_add_bytes(struct inode *inode, loff_t bytes);
3062 void __inode_sub_bytes(struct inode *inode, loff_t bytes);
3063 void inode_sub_bytes(struct inode *inode, loff_t bytes);
3064 static inline loff_t __inode_get_bytes(struct inode *inode)
3065 {
3066         return (((loff_t)inode->i_blocks) << 9) + inode->i_bytes;
3067 }
3068 loff_t inode_get_bytes(struct inode *inode);
3069 void inode_set_bytes(struct inode *inode, loff_t bytes);
3070 const char *simple_get_link(struct dentry *, struct inode *,
3071                             struct delayed_call *);
3072 extern const struct inode_operations simple_symlink_inode_operations;
3073 
3074 extern int iterate_dir(struct file *, struct dir_context *);
3075 
3076 extern int vfs_statx(int, const char __user *, int, struct kstat *, u32);
3077 extern int vfs_statx_fd(unsigned int, struct kstat *, u32, unsigned int);
3078 
3079 static inline int vfs_stat(const char __user *filename, struct kstat *stat)
3080 {
3081         return vfs_statx(AT_FDCWD, filename, AT_NO_AUTOMOUNT,
3082                          stat, STATX_BASIC_STATS);
3083 }
3084 static inline int vfs_lstat(const char __user *name, struct kstat *stat)
3085 {
3086         return vfs_statx(AT_FDCWD, name, AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT,
3087                          stat, STATX_BASIC_STATS);
3088 }
3089 static inline int vfs_fstatat(int dfd, const char __user *filename,
3090                               struct kstat *stat, int flags)
3091 {
3092         return vfs_statx(dfd, filename, flags | AT_NO_AUTOMOUNT,
3093                          stat, STATX_BASIC_STATS);
3094 }
3095 static inline int vfs_fstat(int fd, struct kstat *stat)
3096 {
3097         return vfs_statx_fd(fd, stat, STATX_BASIC_STATS, 0);
3098 }
3099 
3100 
3101 extern const char *vfs_get_link(struct dentry *, struct delayed_call *);
3102 extern int vfs_readlink(struct dentry *, char __user *, int);
3103 
3104 extern int __generic_block_fiemap(struct inode *inode,
3105                                   struct fiemap_extent_info *fieinfo,
3106                                   loff_t start, loff_t len,
3107                                   get_block_t *get_block);
3108 extern int generic_block_fiemap(struct inode *inode,
3109                                 struct fiemap_extent_info *fieinfo, u64 start,
3110                                 u64 len, get_block_t *get_block);
3111 
3112 extern struct file_system_type *get_filesystem(struct file_system_type *fs);
3113 extern void put_filesystem(struct file_system_type *fs);
3114 extern struct file_system_type *get_fs_type(const char *name);
3115 extern struct super_block *get_super(struct block_device *);
3116 extern struct super_block *get_super_thawed(struct block_device *);
3117 extern struct super_block *get_super_exclusive_thawed(struct block_device *bdev);
3118 extern struct super_block *get_active_super(struct block_device *bdev);
3119 extern void drop_super(struct super_block *sb);
3120 extern void drop_super_exclusive(struct super_block *sb);
3121 extern void iterate_supers(void (*)(struct super_block *, void *), void *);
3122 extern void iterate_supers_type(struct file_system_type *,
3123                                 void (*)(struct super_block *, void *), void *);
3124 
3125 extern int dcache_dir_open(struct inode *, struct file *);
3126 extern int dcache_dir_close(struct inode *, struct file *);
3127 extern loff_t dcache_dir_lseek(struct file *, loff_t, int);
3128 extern int dcache_readdir(struct file *, struct dir_context *);
3129 extern int simple_setattr(struct dentry *, struct iattr *);
3130 extern int simple_getattr(const struct path *, struct kstat *, u32, unsigned int);
3131 extern int simple_statfs(struct dentry *, struct kstatfs *);
3132 extern int simple_open(struct inode *inode, struct file *file);
3133 extern int simple_link(struct dentry *, struct inode *, struct dentry *);
3134 extern int simple_unlink(struct inode *, struct dentry *);
3135 extern int simple_rmdir(struct inode *, struct dentry *);
3136 extern int simple_rename(struct inode *, struct dentry *,
3137                          struct inode *, struct dentry *, unsigned int);
3138 extern int noop_fsync(struct file *, loff_t, loff_t, int);
3139 extern int simple_empty(struct dentry *);
3140 extern int simple_readpage(struct file *file, struct page *page);
3141 extern int simple_write_begin(struct file *file, struct address_space *mapping,
3142                         loff_t pos, unsigned len, unsigned flags,
3143                         struct page **pagep, void **fsdata);
3144 extern int simple_write_end(struct file *file, struct address_space *mapping,
3145                         loff_t pos, unsigned len, unsigned copied,
3146                         struct page *page, void *fsdata);
3147 extern int always_delete_dentry(const struct dentry *);
3148 extern struct inode *alloc_anon_inode(struct super_block *);
3149 extern int simple_nosetlease(struct file *, long, struct file_lock **, void **);
3150 extern const struct dentry_operations simple_dentry_operations;
3151 
3152 extern struct dentry *simple_lookup(struct inode *, struct dentry *, unsigned int flags);
3153 extern ssize_t generic_read_dir(struct file *, char __user *, size_t, loff_t *);
3154 extern const struct file_operations simple_dir_operations;
3155 extern const struct inode_operations simple_dir_inode_operations;
3156 extern void make_empty_dir_inode(struct inode *inode);
3157 extern bool is_empty_dir_inode(struct inode *inode);
3158 struct tree_descr { const char *name; const struct file_operations *ops; int mode; };
3159 struct dentry *d_alloc_name(struct dentry *, const char *);
3160 extern int simple_fill_super(struct super_block *, unsigned long,
3161                              const struct tree_descr *);
3162 extern int simple_pin_fs(struct file_system_type *, struct vfsmount **mount, int *count);
3163 extern void simple_release_fs(struct vfsmount **mount, int *count);
3164 
3165 extern ssize_t simple_read_from_buffer(void __user *to, size_t count,
3166                         loff_t *ppos, const void *from, size_t available);
3167 extern ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos,
3168                 const void __user *from, size_t count);
3169 
3170 extern int __generic_file_fsync(struct file *, loff_t, loff_t, int);
3171 extern int generic_file_fsync(struct file *, loff_t, loff_t, int);
3172 
3173 extern int generic_check_addressable(unsigned, u64);
3174 
3175 #ifdef CONFIG_MIGRATION
3176 extern int buffer_migrate_page(struct address_space *,
3177                                 struct page *, struct page *,
3178                                 enum migrate_mode);
3179 #else
3180 #define buffer_migrate_page NULL
3181 #endif
3182 
3183 extern int setattr_prepare(struct dentry *, struct iattr *);
3184 extern int inode_newsize_ok(const struct inode *, loff_t offset);
3185 extern void setattr_copy(struct inode *inode, const struct iattr *attr);
3186 
3187 extern int file_update_time(struct file *file);
3188 
3189 static inline bool io_is_direct(struct file *filp)
3190 {
3191         return (filp->f_flags & O_DIRECT) || IS_DAX(filp->f_mapping->host);
3192 }
3193 
3194 static inline bool vma_is_dax(struct vm_area_struct *vma)
3195 {
3196         return vma->vm_file && IS_DAX(vma->vm_file->f_mapping->host);
3197 }
3198 
3199 static inline bool vma_is_fsdax(struct vm_area_struct *vma)
3200 {
3201         struct inode *inode;
3202 
3203         if (!vma->vm_file)
3204                 return false;
3205         if (!vma_is_dax(vma))
3206                 return false;
3207         inode = file_inode(vma->vm_file);
3208         if (S_ISCHR(inode->i_mode))
3209                 return false; /* device-dax */
3210         return true;
3211 }
3212 
3213 static inline int iocb_flags(struct file *file)
3214 {
3215         int res = 0;
3216         if (file->f_flags & O_APPEND)
3217                 res |= IOCB_APPEND;
3218         if (io_is_direct(file))
3219                 res |= IOCB_DIRECT;
3220         if ((file->f_flags & O_DSYNC) || IS_SYNC(file->f_mapping->host))
3221                 res |= IOCB_DSYNC;
3222         if (file->f_flags & __O_SYNC)
3223                 res |= IOCB_SYNC;
3224         return res;
3225 }
3226 
3227 static inline int kiocb_set_rw_flags(struct kiocb *ki, rwf_t flags)
3228 {
3229         if (unlikely(flags & ~RWF_SUPPORTED))
3230                 return -EOPNOTSUPP;
3231 
3232         if (flags & RWF_NOWAIT) {
3233                 if (!(ki->ki_filp->f_mode & FMODE_NOWAIT))
3234                         return -EOPNOTSUPP;
3235                 ki->ki_flags |= IOCB_NOWAIT;
3236         }
3237         if (flags & RWF_HIPRI)
3238                 ki->ki_flags |= IOCB_HIPRI;
3239         if (flags & RWF_DSYNC)
3240                 ki->ki_flags |= IOCB_DSYNC;
3241         if (flags & RWF_SYNC)
3242                 ki->ki_flags |= (IOCB_DSYNC | IOCB_SYNC);
3243         return 0;
3244 }
3245 
3246 static inline ino_t parent_ino(struct dentry *dentry)
3247 {
3248         ino_t res;
3249 
3250         /*
3251          * Don't strictly need d_lock here? If the parent ino could change
3252          * then surely we'd have a deeper race in the caller?
3253          */
3254         spin_lock(&dentry->d_lock);
3255         res = dentry->d_parent->d_inode->i_ino;
3256         spin_unlock(&dentry->d_lock);
3257         return res;
3258 }
3259 
3260 /* Transaction based IO helpers */
3261 
3262 /*
3263  * An argresp is stored in an allocated page and holds the
3264  * size of the argument or response, along with its content
3265  */
3266 struct simple_transaction_argresp {
3267         ssize_t size;
3268         char data[0];
3269 };
3270 
3271 #define SIMPLE_TRANSACTION_LIMIT (PAGE_SIZE - sizeof(struct simple_transaction_argresp))
3272 
3273 char *simple_transaction_get(struct file *file, const char __user *buf,
3274                                 size_t size);
3275 ssize_t simple_transaction_read(struct file *file, char __user *buf,
3276                                 size_t size, loff_t *pos);
3277 int simple_transaction_release(struct inode *inode, struct file *file);
3278 
3279 void simple_transaction_set(struct file *file, size_t n);
3280 
3281 /*
3282  * simple attribute files
3283  *
3284  * These attributes behave similar to those in sysfs:
3285  *
3286  * Writing to an attribute immediately sets a value, an open file can be
3287  * written to multiple times.
3288  *
3289  * Reading from an attribute creates a buffer from the value that might get
3290  * read with multiple read calls. When the attribute has been read
3291  * completely, no further read calls are possible until the file is opened
3292  * again.
3293  *
3294  * All attributes contain a text representation of a numeric value
3295  * that are accessed with the get() and set() functions.
3296  */
3297 #define DEFINE_SIMPLE_ATTRIBUTE(__fops, __get, __set, __fmt)            \
3298 static int __fops ## _open(struct inode *inode, struct file *file)      \
3299 {                                                                       \
3300         __simple_attr_check_format(__fmt, 0ull);                        \
3301         return simple_attr_open(inode, file, __get, __set, __fmt);      \
3302 }                                                                       \
3303 static const struct file_operations __fops = {                          \
3304         .owner   = THIS_MODULE,                                         \
3305         .open    = __fops ## _open,                                     \
3306         .release = simple_attr_release,                                 \
3307         .read    = simple_attr_read,                                    \
3308         .write   = simple_attr_write,                                   \
3309         .llseek  = generic_file_llseek,                                 \
3310 }
3311 
3312 static inline __printf(1, 2)
3313 void __simple_attr_check_format(const char *fmt, ...)
3314 {
3315         /* don't do anything, just let the compiler check the arguments; */
3316 }
3317 
3318 int simple_attr_open(struct inode *inode, struct file *file,
3319                      int (*get)(void *, u64 *), int (*set)(void *, u64),
3320                      const char *fmt);
3321 int simple_attr_release(struct inode *inode, struct file *file);
3322 ssize_t simple_attr_read(struct file *file, char __user *buf,
3323                          size_t len, loff_t *ppos);
3324 ssize_t simple_attr_write(struct file *file, const char __user *buf,
3325                           size_t len, loff_t *ppos);
3326 
3327 struct ctl_table;
3328 int proc_nr_files(struct ctl_table *table, int write,
3329                   void __user *buffer, size_t *lenp, loff_t *ppos);
3330 int proc_nr_dentry(struct ctl_table *table, int write,
3331                   void __user *buffer, size_t *lenp, loff_t *ppos);
3332 int proc_nr_inodes(struct ctl_table *table, int write,
3333                    void __user *buffer, size_t *lenp, loff_t *ppos);
3334 int __init get_filesystem_list(char *buf);
3335 
3336 #define __FMODE_EXEC            ((__force int) FMODE_EXEC)
3337 #define __FMODE_NONOTIFY        ((__force int) FMODE_NONOTIFY)
3338 
3339 #define ACC_MODE(x) ("\004\002\006\006"[(x)&O_ACCMODE])
3340 #define OPEN_FMODE(flag) ((__force fmode_t)(((flag + 1) & O_ACCMODE) | \
3341                                             (flag & __FMODE_NONOTIFY)))
3342 
3343 static inline bool is_sxid(umode_t mode)
3344 {
3345         return (mode & S_ISUID) || ((mode & S_ISGID) && (mode & S_IXGRP));
3346 }
3347 
3348 static inline int check_sticky(struct inode *dir, struct inode *inode)
3349 {
3350         if (!(dir->i_mode & S_ISVTX))
3351                 return 0;
3352 
3353         return __check_sticky(dir, inode);
3354 }
3355 
3356 static inline void inode_has_no_xattr(struct inode *inode)
3357 {
3358         if (!is_sxid(inode->i_mode) && (inode->i_sb->s_flags & SB_NOSEC))
3359                 inode->i_flags |= S_NOSEC;
3360 }
3361 
3362 static inline bool is_root_inode(struct inode *inode)
3363 {
3364         return inode == inode->i_sb->s_root->d_inode;
3365 }
3366 
3367 static inline bool dir_emit(struct dir_context *ctx,
3368                             const char *name, int namelen,
3369                             u64 ino, unsigned type)
3370 {
3371         return ctx->actor(ctx, name, namelen, ctx->pos, ino, type) == 0;
3372 }
3373 static inline bool dir_emit_dot(struct file *file, struct dir_context *ctx)
3374 {
3375         return ctx->actor(ctx, ".", 1, ctx->pos,
3376                           file->f_path.dentry->d_inode->i_ino, DT_DIR) == 0;
3377 }
3378 static inline bool dir_emit_dotdot(struct file *file, struct dir_context *ctx)
3379 {
3380         return ctx->actor(ctx, "..", 2, ctx->pos,
3381                           parent_ino(file->f_path.dentry), DT_DIR) == 0;
3382 }
3383 static inline bool dir_emit_dots(struct file *file, struct dir_context *ctx)
3384 {
3385         if (ctx->pos == 0) {
3386                 if (!dir_emit_dot(file, ctx))
3387                         return false;
3388                 ctx->pos = 1;
3389         }
3390         if (ctx->pos == 1) {
3391                 if (!dir_emit_dotdot(file, ctx))
3392                         return false;
3393                 ctx->pos = 2;
3394         }
3395         return true;
3396 }
3397 static inline bool dir_relax(struct inode *inode)
3398 {
3399         inode_unlock(inode);
3400         inode_lock(inode);
3401         return !IS_DEADDIR(inode);
3402 }
3403 
3404 static inline bool dir_relax_shared(struct inode *inode)
3405 {
3406         inode_unlock_shared(inode);
3407         inode_lock_shared(inode);
3408         return !IS_DEADDIR(inode);
3409 }
3410 
3411 extern bool path_noexec(const struct path *path);
3412 extern void inode_nohighmem(struct inode *inode);
3413 
3414 #endif /* _LINUX_FS_H */
3415 

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