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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         atomic64_t              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 static inline void inode_lock_shared_nested(struct inode *inode, unsigned subclass)
752 {
753         down_read_nested(&inode->i_rwsem, subclass);
754 }
755 
756 void lock_two_nondirectories(struct inode *, struct inode*);
757 void unlock_two_nondirectories(struct inode *, struct inode*);
758 
759 /*
760  * NOTE: in a 32bit arch with a preemptable kernel and
761  * an UP compile the i_size_read/write must be atomic
762  * with respect to the local cpu (unlike with preempt disabled),
763  * but they don't need to be atomic with respect to other cpus like in
764  * true SMP (so they need either to either locally disable irq around
765  * the read or for example on x86 they can be still implemented as a
766  * cmpxchg8b without the need of the lock prefix). For SMP compiles
767  * and 64bit archs it makes no difference if preempt is enabled or not.
768  */
769 static inline loff_t i_size_read(const struct inode *inode)
770 {
771 #if BITS_PER_LONG==32 && defined(CONFIG_SMP)
772         loff_t i_size;
773         unsigned int seq;
774 
775         do {
776                 seq = read_seqcount_begin(&inode->i_size_seqcount);
777                 i_size = inode->i_size;
778         } while (read_seqcount_retry(&inode->i_size_seqcount, seq));
779         return i_size;
780 #elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPT)
781         loff_t i_size;
782 
783         preempt_disable();
784         i_size = inode->i_size;
785         preempt_enable();
786         return i_size;
787 #else
788         return inode->i_size;
789 #endif
790 }
791 
792 /*
793  * NOTE: unlike i_size_read(), i_size_write() does need locking around it
794  * (normally i_mutex), otherwise on 32bit/SMP an update of i_size_seqcount
795  * can be lost, resulting in subsequent i_size_read() calls spinning forever.
796  */
797 static inline void i_size_write(struct inode *inode, loff_t i_size)
798 {
799 #if BITS_PER_LONG==32 && defined(CONFIG_SMP)
800         preempt_disable();
801         write_seqcount_begin(&inode->i_size_seqcount);
802         inode->i_size = i_size;
803         write_seqcount_end(&inode->i_size_seqcount);
804         preempt_enable();
805 #elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPT)
806         preempt_disable();
807         inode->i_size = i_size;
808         preempt_enable();
809 #else
810         inode->i_size = i_size;
811 #endif
812 }
813 
814 static inline unsigned iminor(const struct inode *inode)
815 {
816         return MINOR(inode->i_rdev);
817 }
818 
819 static inline unsigned imajor(const struct inode *inode)
820 {
821         return MAJOR(inode->i_rdev);
822 }
823 
824 extern struct block_device *I_BDEV(struct inode *inode);
825 
826 struct fown_struct {
827         rwlock_t lock;          /* protects pid, uid, euid fields */
828         struct pid *pid;        /* pid or -pgrp where SIGIO should be sent */
829         enum pid_type pid_type; /* Kind of process group SIGIO should be sent to */
830         kuid_t uid, euid;       /* uid/euid of process setting the owner */
831         int signum;             /* posix.1b rt signal to be delivered on IO */
832 };
833 
834 /*
835  * Track a single file's readahead state
836  */
837 struct file_ra_state {
838         pgoff_t start;                  /* where readahead started */
839         unsigned int size;              /* # of readahead pages */
840         unsigned int async_size;        /* do asynchronous readahead when
841                                            there are only # of pages ahead */
842 
843         unsigned int ra_pages;          /* Maximum readahead window */
844         unsigned int mmap_miss;         /* Cache miss stat for mmap accesses */
845         loff_t prev_pos;                /* Cache last read() position */
846 };
847 
848 /*
849  * Check if @index falls in the readahead windows.
850  */
851 static inline int ra_has_index(struct file_ra_state *ra, pgoff_t index)
852 {
853         return (index >= ra->start &&
854                 index <  ra->start + ra->size);
855 }
856 
857 struct file {
858         union {
859                 struct llist_node       fu_llist;
860                 struct rcu_head         fu_rcuhead;
861         } f_u;
862         struct path             f_path;
863         struct inode            *f_inode;       /* cached value */
864         const struct file_operations    *f_op;
865 
866         /*
867          * Protects f_ep_links, f_flags.
868          * Must not be taken from IRQ context.
869          */
870         spinlock_t              f_lock;
871         enum rw_hint            f_write_hint;
872         atomic_long_t           f_count;
873         unsigned int            f_flags;
874         fmode_t                 f_mode;
875         struct mutex            f_pos_lock;
876         loff_t                  f_pos;
877         struct fown_struct      f_owner;
878         const struct cred       *f_cred;
879         struct file_ra_state    f_ra;
880 
881         u64                     f_version;
882 #ifdef CONFIG_SECURITY
883         void                    *f_security;
884 #endif
885         /* needed for tty driver, and maybe others */
886         void                    *private_data;
887 
888 #ifdef CONFIG_EPOLL
889         /* Used by fs/eventpoll.c to link all the hooks to this file */
890         struct list_head        f_ep_links;
891         struct list_head        f_tfile_llink;
892 #endif /* #ifdef CONFIG_EPOLL */
893         struct address_space    *f_mapping;
894         errseq_t                f_wb_err;
895 } __randomize_layout
896   __attribute__((aligned(4)));  /* lest something weird decides that 2 is OK */
897 
898 struct file_handle {
899         __u32 handle_bytes;
900         int handle_type;
901         /* file identifier */
902         unsigned char f_handle[0];
903 };
904 
905 static inline struct file *get_file(struct file *f)
906 {
907         atomic_long_inc(&f->f_count);
908         return f;
909 }
910 #define get_file_rcu(x) atomic_long_inc_not_zero(&(x)->f_count)
911 #define fput_atomic(x)  atomic_long_add_unless(&(x)->f_count, -1, 1)
912 #define file_count(x)   atomic_long_read(&(x)->f_count)
913 
914 #define MAX_NON_LFS     ((1UL<<31) - 1)
915 
916 /* Page cache limit. The filesystems should put that into their s_maxbytes 
917    limits, otherwise bad things can happen in VM. */ 
918 #if BITS_PER_LONG==32
919 #define MAX_LFS_FILESIZE        ((loff_t)ULONG_MAX << PAGE_SHIFT)
920 #elif BITS_PER_LONG==64
921 #define MAX_LFS_FILESIZE        ((loff_t)LLONG_MAX)
922 #endif
923 
924 #define FL_POSIX        1
925 #define FL_FLOCK        2
926 #define FL_DELEG        4       /* NFSv4 delegation */
927 #define FL_ACCESS       8       /* not trying to lock, just looking */
928 #define FL_EXISTS       16      /* when unlocking, test for existence */
929 #define FL_LEASE        32      /* lease held on this file */
930 #define FL_CLOSE        64      /* unlock on close */
931 #define FL_SLEEP        128     /* A blocking lock */
932 #define FL_DOWNGRADE_PENDING    256 /* Lease is being downgraded */
933 #define FL_UNLOCK_PENDING       512 /* Lease is being broken */
934 #define FL_OFDLCK       1024    /* lock is "owned" by struct file */
935 #define FL_LAYOUT       2048    /* outstanding pNFS layout */
936 
937 #define FL_CLOSE_POSIX (FL_POSIX | FL_CLOSE)
938 
939 /*
940  * Special return value from posix_lock_file() and vfs_lock_file() for
941  * asynchronous locking.
942  */
943 #define FILE_LOCK_DEFERRED 1
944 
945 /* legacy typedef, should eventually be removed */
946 typedef void *fl_owner_t;
947 
948 struct file_lock;
949 
950 struct file_lock_operations {
951         void (*fl_copy_lock)(struct file_lock *, struct file_lock *);
952         void (*fl_release_private)(struct file_lock *);
953 };
954 
955 struct lock_manager_operations {
956         int (*lm_compare_owner)(struct file_lock *, struct file_lock *);
957         unsigned long (*lm_owner_key)(struct file_lock *);
958         fl_owner_t (*lm_get_owner)(fl_owner_t);
959         void (*lm_put_owner)(fl_owner_t);
960         void (*lm_notify)(struct file_lock *);  /* unblock callback */
961         int (*lm_grant)(struct file_lock *, int);
962         bool (*lm_break)(struct file_lock *);
963         int (*lm_change)(struct file_lock *, int, struct list_head *);
964         void (*lm_setup)(struct file_lock *, void **);
965 };
966 
967 struct lock_manager {
968         struct list_head list;
969         /*
970          * NFSv4 and up also want opens blocked during the grace period;
971          * NLM doesn't care:
972          */
973         bool block_opens;
974 };
975 
976 struct net;
977 void locks_start_grace(struct net *, struct lock_manager *);
978 void locks_end_grace(struct lock_manager *);
979 bool locks_in_grace(struct net *);
980 bool opens_in_grace(struct net *);
981 
982 /* that will die - we need it for nfs_lock_info */
983 #include <linux/nfs_fs_i.h>
984 
985 /*
986  * struct file_lock represents a generic "file lock". It's used to represent
987  * POSIX byte range locks, BSD (flock) locks, and leases. It's important to
988  * note that the same struct is used to represent both a request for a lock and
989  * the lock itself, but the same object is never used for both.
990  *
991  * FIXME: should we create a separate "struct lock_request" to help distinguish
992  * these two uses?
993  *
994  * The varous i_flctx lists are ordered by:
995  *
996  * 1) lock owner
997  * 2) lock range start
998  * 3) lock range end
999  *
1000  * Obviously, the last two criteria only matter for POSIX locks.
1001  */
1002 struct file_lock {
1003         struct file_lock *fl_next;      /* singly linked list for this inode  */
1004         struct list_head fl_list;       /* link into file_lock_context */
1005         struct hlist_node fl_link;      /* node in global lists */
1006         struct list_head fl_block;      /* circular list of blocked processes */
1007         fl_owner_t fl_owner;
1008         unsigned int fl_flags;
1009         unsigned char fl_type;
1010         unsigned int fl_pid;
1011         int fl_link_cpu;                /* what cpu's list is this on? */
1012         wait_queue_head_t fl_wait;
1013         struct file *fl_file;
1014         loff_t fl_start;
1015         loff_t fl_end;
1016 
1017         struct fasync_struct *  fl_fasync; /* for lease break notifications */
1018         /* for lease breaks: */
1019         unsigned long fl_break_time;
1020         unsigned long fl_downgrade_time;
1021 
1022         const struct file_lock_operations *fl_ops;      /* Callbacks for filesystems */
1023         const struct lock_manager_operations *fl_lmops; /* Callbacks for lockmanagers */
1024         union {
1025                 struct nfs_lock_info    nfs_fl;
1026                 struct nfs4_lock_info   nfs4_fl;
1027                 struct {
1028                         struct list_head link;  /* link in AFS vnode's pending_locks list */
1029                         int state;              /* state of grant or error if -ve */
1030                 } afs;
1031         } fl_u;
1032 } __randomize_layout;
1033 
1034 struct file_lock_context {
1035         spinlock_t              flc_lock;
1036         struct list_head        flc_flock;
1037         struct list_head        flc_posix;
1038         struct list_head        flc_lease;
1039 };
1040 
1041 /* The following constant reflects the upper bound of the file/locking space */
1042 #ifndef OFFSET_MAX
1043 #define INT_LIMIT(x)    (~((x)1 << (sizeof(x)*8 - 1)))
1044 #define OFFSET_MAX      INT_LIMIT(loff_t)
1045 #define OFFT_OFFSET_MAX INT_LIMIT(off_t)
1046 #endif
1047 
1048 extern void send_sigio(struct fown_struct *fown, int fd, int band);
1049 
1050 /*
1051  * Return the inode to use for locking
1052  *
1053  * For overlayfs this should be the overlay inode, not the real inode returned
1054  * by file_inode().  For any other fs file_inode(filp) and locks_inode(filp) are
1055  * equal.
1056  */
1057 static inline struct inode *locks_inode(const struct file *f)
1058 {
1059         return f->f_path.dentry->d_inode;
1060 }
1061 
1062 #ifdef CONFIG_FILE_LOCKING
1063 extern int fcntl_getlk(struct file *, unsigned int, struct flock *);
1064 extern int fcntl_setlk(unsigned int, struct file *, unsigned int,
1065                         struct flock *);
1066 
1067 #if BITS_PER_LONG == 32
1068 extern int fcntl_getlk64(struct file *, unsigned int, struct flock64 *);
1069 extern int fcntl_setlk64(unsigned int, struct file *, unsigned int,
1070                         struct flock64 *);
1071 #endif
1072 
1073 extern int fcntl_setlease(unsigned int fd, struct file *filp, long arg);
1074 extern int fcntl_getlease(struct file *filp);
1075 
1076 /* fs/locks.c */
1077 void locks_free_lock_context(struct inode *inode);
1078 void locks_free_lock(struct file_lock *fl);
1079 extern void locks_init_lock(struct file_lock *);
1080 extern struct file_lock * locks_alloc_lock(void);
1081 extern void locks_copy_lock(struct file_lock *, struct file_lock *);
1082 extern void locks_copy_conflock(struct file_lock *, struct file_lock *);
1083 extern void locks_remove_posix(struct file *, fl_owner_t);
1084 extern void locks_remove_file(struct file *);
1085 extern void locks_release_private(struct file_lock *);
1086 extern void posix_test_lock(struct file *, struct file_lock *);
1087 extern int posix_lock_file(struct file *, struct file_lock *, struct file_lock *);
1088 extern int posix_unblock_lock(struct file_lock *);
1089 extern int vfs_test_lock(struct file *, struct file_lock *);
1090 extern int vfs_lock_file(struct file *, unsigned int, struct file_lock *, struct file_lock *);
1091 extern int vfs_cancel_lock(struct file *filp, struct file_lock *fl);
1092 extern int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl);
1093 extern int __break_lease(struct inode *inode, unsigned int flags, unsigned int type);
1094 extern void lease_get_mtime(struct inode *, struct timespec *time);
1095 extern int generic_setlease(struct file *, long, struct file_lock **, void **priv);
1096 extern int vfs_setlease(struct file *, long, struct file_lock **, void **);
1097 extern int lease_modify(struct file_lock *, int, struct list_head *);
1098 struct files_struct;
1099 extern void show_fd_locks(struct seq_file *f,
1100                          struct file *filp, struct files_struct *files);
1101 #else /* !CONFIG_FILE_LOCKING */
1102 static inline int fcntl_getlk(struct file *file, unsigned int cmd,
1103                               struct flock __user *user)
1104 {
1105         return -EINVAL;
1106 }
1107 
1108 static inline int fcntl_setlk(unsigned int fd, struct file *file,
1109                               unsigned int cmd, struct flock __user *user)
1110 {
1111         return -EACCES;
1112 }
1113 
1114 #if BITS_PER_LONG == 32
1115 static inline int fcntl_getlk64(struct file *file, unsigned int cmd,
1116                                 struct flock64 __user *user)
1117 {
1118         return -EINVAL;
1119 }
1120 
1121 static inline int fcntl_setlk64(unsigned int fd, struct file *file,
1122                                 unsigned int cmd, struct flock64 __user *user)
1123 {
1124         return -EACCES;
1125 }
1126 #endif
1127 static inline int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
1128 {
1129         return -EINVAL;
1130 }
1131 
1132 static inline int fcntl_getlease(struct file *filp)
1133 {
1134         return F_UNLCK;
1135 }
1136 
1137 static inline void
1138 locks_free_lock_context(struct inode *inode)
1139 {
1140 }
1141 
1142 static inline void locks_init_lock(struct file_lock *fl)
1143 {
1144         return;
1145 }
1146 
1147 static inline void locks_copy_conflock(struct file_lock *new, struct file_lock *fl)
1148 {
1149         return;
1150 }
1151 
1152 static inline void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
1153 {
1154         return;
1155 }
1156 
1157 static inline void locks_remove_posix(struct file *filp, fl_owner_t owner)
1158 {
1159         return;
1160 }
1161 
1162 static inline void locks_remove_file(struct file *filp)
1163 {
1164         return;
1165 }
1166 
1167 static inline void posix_test_lock(struct file *filp, struct file_lock *fl)
1168 {
1169         return;
1170 }
1171 
1172 static inline int posix_lock_file(struct file *filp, struct file_lock *fl,
1173                                   struct file_lock *conflock)
1174 {
1175         return -ENOLCK;
1176 }
1177 
1178 static inline int posix_unblock_lock(struct file_lock *waiter)
1179 {
1180         return -ENOENT;
1181 }
1182 
1183 static inline int vfs_test_lock(struct file *filp, struct file_lock *fl)
1184 {
1185         return 0;
1186 }
1187 
1188 static inline int vfs_lock_file(struct file *filp, unsigned int cmd,
1189                                 struct file_lock *fl, struct file_lock *conf)
1190 {
1191         return -ENOLCK;
1192 }
1193 
1194 static inline int vfs_cancel_lock(struct file *filp, struct file_lock *fl)
1195 {
1196         return 0;
1197 }
1198 
1199 static inline int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl)
1200 {
1201         return -ENOLCK;
1202 }
1203 
1204 static inline int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
1205 {
1206         return 0;
1207 }
1208 
1209 static inline void lease_get_mtime(struct inode *inode, struct timespec *time)
1210 {
1211         return;
1212 }
1213 
1214 static inline int generic_setlease(struct file *filp, long arg,
1215                                     struct file_lock **flp, void **priv)
1216 {
1217         return -EINVAL;
1218 }
1219 
1220 static inline int vfs_setlease(struct file *filp, long arg,
1221                                struct file_lock **lease, void **priv)
1222 {
1223         return -EINVAL;
1224 }
1225 
1226 static inline int lease_modify(struct file_lock *fl, int arg,
1227                                struct list_head *dispose)
1228 {
1229         return -EINVAL;
1230 }
1231 
1232 struct files_struct;
1233 static inline void show_fd_locks(struct seq_file *f,
1234                         struct file *filp, struct files_struct *files) {}
1235 #endif /* !CONFIG_FILE_LOCKING */
1236 
1237 static inline struct inode *file_inode(const struct file *f)
1238 {
1239         return f->f_inode;
1240 }
1241 
1242 static inline struct dentry *file_dentry(const struct file *file)
1243 {
1244         return d_real(file->f_path.dentry, file_inode(file), 0, 0);
1245 }
1246 
1247 static inline int locks_lock_file_wait(struct file *filp, struct file_lock *fl)
1248 {
1249         return locks_lock_inode_wait(locks_inode(filp), fl);
1250 }
1251 
1252 struct fasync_struct {
1253         spinlock_t              fa_lock;
1254         int                     magic;
1255         int                     fa_fd;
1256         struct fasync_struct    *fa_next; /* singly linked list */
1257         struct file             *fa_file;
1258         struct rcu_head         fa_rcu;
1259 };
1260 
1261 #define FASYNC_MAGIC 0x4601
1262 
1263 /* SMP safe fasync helpers: */
1264 extern int fasync_helper(int, struct file *, int, struct fasync_struct **);
1265 extern struct fasync_struct *fasync_insert_entry(int, struct file *, struct fasync_struct **, struct fasync_struct *);
1266 extern int fasync_remove_entry(struct file *, struct fasync_struct **);
1267 extern struct fasync_struct *fasync_alloc(void);
1268 extern void fasync_free(struct fasync_struct *);
1269 
1270 /* can be called from interrupts */
1271 extern void kill_fasync(struct fasync_struct **, int, int);
1272 
1273 extern void __f_setown(struct file *filp, struct pid *, enum pid_type, int force);
1274 extern int f_setown(struct file *filp, unsigned long arg, int force);
1275 extern void f_delown(struct file *filp);
1276 extern pid_t f_getown(struct file *filp);
1277 extern int send_sigurg(struct fown_struct *fown);
1278 
1279 /*
1280  * sb->s_flags.  Note that these mirror the equivalent MS_* flags where
1281  * represented in both.
1282  */
1283 #define SB_RDONLY        1      /* Mount read-only */
1284 #define SB_NOSUID        2      /* Ignore suid and sgid bits */
1285 #define SB_NODEV         4      /* Disallow access to device special files */
1286 #define SB_NOEXEC        8      /* Disallow program execution */
1287 #define SB_SYNCHRONOUS  16      /* Writes are synced at once */
1288 #define SB_MANDLOCK     64      /* Allow mandatory locks on an FS */
1289 #define SB_DIRSYNC      128     /* Directory modifications are synchronous */
1290 #define SB_NOATIME      1024    /* Do not update access times. */
1291 #define SB_NODIRATIME   2048    /* Do not update directory access times */
1292 #define SB_SILENT       32768
1293 #define SB_POSIXACL     (1<<16) /* VFS does not apply the umask */
1294 #define SB_KERNMOUNT    (1<<22) /* this is a kern_mount call */
1295 #define SB_I_VERSION    (1<<23) /* Update inode I_version field */
1296 #define SB_LAZYTIME     (1<<25) /* Update the on-disk [acm]times lazily */
1297 
1298 /* These sb flags are internal to the kernel */
1299 #define SB_SUBMOUNT     (1<<26)
1300 #define SB_NOREMOTELOCK (1<<27)
1301 #define SB_NOSEC        (1<<28)
1302 #define SB_BORN         (1<<29)
1303 #define SB_ACTIVE       (1<<30)
1304 #define SB_NOUSER       (1<<31)
1305 
1306 /*
1307  *      Umount options
1308  */
1309 
1310 #define MNT_FORCE       0x00000001      /* Attempt to forcibily umount */
1311 #define MNT_DETACH      0x00000002      /* Just detach from the tree */
1312 #define MNT_EXPIRE      0x00000004      /* Mark for expiry */
1313 #define UMOUNT_NOFOLLOW 0x00000008      /* Don't follow symlink on umount */
1314 #define UMOUNT_UNUSED   0x80000000      /* Flag guaranteed to be unused */
1315 
1316 /* sb->s_iflags */
1317 #define SB_I_CGROUPWB   0x00000001      /* cgroup-aware writeback enabled */
1318 #define SB_I_NOEXEC     0x00000002      /* Ignore executables on this fs */
1319 #define SB_I_NODEV      0x00000004      /* Ignore devices on this fs */
1320 #define SB_I_MULTIROOT  0x00000008      /* Multiple roots to the dentry tree */
1321 
1322 /* sb->s_iflags to limit user namespace mounts */
1323 #define SB_I_USERNS_VISIBLE             0x00000010 /* fstype already mounted */
1324 
1325 /* Possible states of 'frozen' field */
1326 enum {
1327         SB_UNFROZEN = 0,                /* FS is unfrozen */
1328         SB_FREEZE_WRITE = 1,            /* Writes, dir ops, ioctls frozen */
1329         SB_FREEZE_PAGEFAULT = 2,        /* Page faults stopped as well */
1330         SB_FREEZE_FS = 3,               /* For internal FS use (e.g. to stop
1331                                          * internal threads if needed) */
1332         SB_FREEZE_COMPLETE = 4,         /* ->freeze_fs finished successfully */
1333 };
1334 
1335 #define SB_FREEZE_LEVELS (SB_FREEZE_COMPLETE - 1)
1336 
1337 struct sb_writers {
1338         int                             frozen;         /* Is sb frozen? */
1339         wait_queue_head_t               wait_unfrozen;  /* for get_super_thawed() */
1340         struct percpu_rw_semaphore      rw_sem[SB_FREEZE_LEVELS];
1341 };
1342 
1343 struct super_block {
1344         struct list_head        s_list;         /* Keep this first */
1345         dev_t                   s_dev;          /* search index; _not_ kdev_t */
1346         unsigned char           s_blocksize_bits;
1347         unsigned long           s_blocksize;
1348         loff_t                  s_maxbytes;     /* Max file size */
1349         struct file_system_type *s_type;
1350         const struct super_operations   *s_op;
1351         const struct dquot_operations   *dq_op;
1352         const struct quotactl_ops       *s_qcop;
1353         const struct export_operations *s_export_op;
1354         unsigned long           s_flags;
1355         unsigned long           s_iflags;       /* internal SB_I_* flags */
1356         unsigned long           s_magic;
1357         struct dentry           *s_root;
1358         struct rw_semaphore     s_umount;
1359         int                     s_count;
1360         atomic_t                s_active;
1361 #ifdef CONFIG_SECURITY
1362         void                    *s_security;
1363 #endif
1364         const struct xattr_handler **s_xattr;
1365 
1366         const struct fscrypt_operations *s_cop;
1367 
1368         struct hlist_bl_head    s_roots;        /* alternate root dentries for NFS */
1369         struct list_head        s_mounts;       /* list of mounts; _not_ for fs use */
1370         struct block_device     *s_bdev;
1371         struct backing_dev_info *s_bdi;
1372         struct mtd_info         *s_mtd;
1373         struct hlist_node       s_instances;
1374         unsigned int            s_quota_types;  /* Bitmask of supported quota types */
1375         struct quota_info       s_dquot;        /* Diskquota specific options */
1376 
1377         struct sb_writers       s_writers;
1378 
1379         char                    s_id[32];       /* Informational name */
1380         uuid_t                  s_uuid;         /* UUID */
1381 
1382         void                    *s_fs_info;     /* Filesystem private info */
1383         unsigned int            s_max_links;
1384         fmode_t                 s_mode;
1385 
1386         /* Granularity of c/m/atime in ns.
1387            Cannot be worse than a second */
1388         u32                s_time_gran;
1389 
1390         /*
1391          * The next field is for VFS *only*. No filesystems have any business
1392          * even looking at it. You had been warned.
1393          */
1394         struct mutex s_vfs_rename_mutex;        /* Kludge */
1395 
1396         /*
1397          * Filesystem subtype.  If non-empty the filesystem type field
1398          * in /proc/mounts will be "type.subtype"
1399          */
1400         char *s_subtype;
1401 
1402         const struct dentry_operations *s_d_op; /* default d_op for dentries */
1403 
1404         /*
1405          * Saved pool identifier for cleancache (-1 means none)
1406          */
1407         int cleancache_poolid;
1408 
1409         struct shrinker s_shrink;       /* per-sb shrinker handle */
1410 
1411         /* Number of inodes with nlink == 0 but still referenced */
1412         atomic_long_t s_remove_count;
1413 
1414         /* Being remounted read-only */
1415         int s_readonly_remount;
1416 
1417         /* AIO completions deferred from interrupt context */
1418         struct workqueue_struct *s_dio_done_wq;
1419         struct hlist_head s_pins;
1420 
1421         /*
1422          * Owning user namespace and default context in which to
1423          * interpret filesystem uids, gids, quotas, device nodes,
1424          * xattrs and security labels.
1425          */
1426         struct user_namespace *s_user_ns;
1427 
1428         /*
1429          * Keep the lru lists last in the structure so they always sit on their
1430          * own individual cachelines.
1431          */
1432         struct list_lru         s_dentry_lru ____cacheline_aligned_in_smp;
1433         struct list_lru         s_inode_lru ____cacheline_aligned_in_smp;
1434         struct rcu_head         rcu;
1435         struct work_struct      destroy_work;
1436 
1437         struct mutex            s_sync_lock;    /* sync serialisation lock */
1438 
1439         /*
1440          * Indicates how deep in a filesystem stack this SB is
1441          */
1442         int s_stack_depth;
1443 
1444         /* s_inode_list_lock protects s_inodes */
1445         spinlock_t              s_inode_list_lock ____cacheline_aligned_in_smp;
1446         struct list_head        s_inodes;       /* all inodes */
1447 
1448         spinlock_t              s_inode_wblist_lock;
1449         struct list_head        s_inodes_wb;    /* writeback inodes */
1450 } __randomize_layout;
1451 
1452 /* Helper functions so that in most cases filesystems will
1453  * not need to deal directly with kuid_t and kgid_t and can
1454  * instead deal with the raw numeric values that are stored
1455  * in the filesystem.
1456  */
1457 static inline uid_t i_uid_read(const struct inode *inode)
1458 {
1459         return from_kuid(inode->i_sb->s_user_ns, inode->i_uid);
1460 }
1461 
1462 static inline gid_t i_gid_read(const struct inode *inode)
1463 {
1464         return from_kgid(inode->i_sb->s_user_ns, inode->i_gid);
1465 }
1466 
1467 static inline void i_uid_write(struct inode *inode, uid_t uid)
1468 {
1469         inode->i_uid = make_kuid(inode->i_sb->s_user_ns, uid);
1470 }
1471 
1472 static inline void i_gid_write(struct inode *inode, gid_t gid)
1473 {
1474         inode->i_gid = make_kgid(inode->i_sb->s_user_ns, gid);
1475 }
1476 
1477 extern struct timespec current_time(struct inode *inode);
1478 
1479 /*
1480  * Snapshotting support.
1481  */
1482 
1483 void __sb_end_write(struct super_block *sb, int level);
1484 int __sb_start_write(struct super_block *sb, int level, bool wait);
1485 
1486 #define __sb_writers_acquired(sb, lev)  \
1487         percpu_rwsem_acquire(&(sb)->s_writers.rw_sem[(lev)-1], 1, _THIS_IP_)
1488 #define __sb_writers_release(sb, lev)   \
1489         percpu_rwsem_release(&(sb)->s_writers.rw_sem[(lev)-1], 1, _THIS_IP_)
1490 
1491 /**
1492  * sb_end_write - drop write access to a superblock
1493  * @sb: the super we wrote to
1494  *
1495  * Decrement number of writers to the filesystem. Wake up possible waiters
1496  * wanting to freeze the filesystem.
1497  */
1498 static inline void sb_end_write(struct super_block *sb)
1499 {
1500         __sb_end_write(sb, SB_FREEZE_WRITE);
1501 }
1502 
1503 /**
1504  * sb_end_pagefault - drop write access to a superblock from a page fault
1505  * @sb: the super we wrote to
1506  *
1507  * Decrement number of processes handling write page fault to the filesystem.
1508  * Wake up possible waiters wanting to freeze the filesystem.
1509  */
1510 static inline void sb_end_pagefault(struct super_block *sb)
1511 {
1512         __sb_end_write(sb, SB_FREEZE_PAGEFAULT);
1513 }
1514 
1515 /**
1516  * sb_end_intwrite - drop write access to a superblock for internal fs purposes
1517  * @sb: the super we wrote to
1518  *
1519  * Decrement fs-internal number of writers to the filesystem.  Wake up possible
1520  * waiters wanting to freeze the filesystem.
1521  */
1522 static inline void sb_end_intwrite(struct super_block *sb)
1523 {
1524         __sb_end_write(sb, SB_FREEZE_FS);
1525 }
1526 
1527 /**
1528  * sb_start_write - get write access to a superblock
1529  * @sb: the super we write to
1530  *
1531  * When a process wants to write data or metadata to a file system (i.e. dirty
1532  * a page or an inode), it should embed the operation in a sb_start_write() -
1533  * sb_end_write() pair to get exclusion against file system freezing. This
1534  * function increments number of writers preventing freezing. If the file
1535  * system is already frozen, the function waits until the file system is
1536  * thawed.
1537  *
1538  * Since freeze protection behaves as a lock, users have to preserve
1539  * ordering of freeze protection and other filesystem locks. Generally,
1540  * freeze protection should be the outermost lock. In particular, we have:
1541  *
1542  * sb_start_write
1543  *   -> i_mutex                 (write path, truncate, directory ops, ...)
1544  *   -> s_umount                (freeze_super, thaw_super)
1545  */
1546 static inline void sb_start_write(struct super_block *sb)
1547 {
1548         __sb_start_write(sb, SB_FREEZE_WRITE, true);
1549 }
1550 
1551 static inline int sb_start_write_trylock(struct super_block *sb)
1552 {
1553         return __sb_start_write(sb, SB_FREEZE_WRITE, false);
1554 }
1555 
1556 /**
1557  * sb_start_pagefault - get write access to a superblock from a page fault
1558  * @sb: the super we write to
1559  *
1560  * When a process starts handling write page fault, it should embed the
1561  * operation into sb_start_pagefault() - sb_end_pagefault() pair to get
1562  * exclusion against file system freezing. This is needed since the page fault
1563  * is going to dirty a page. This function increments number of running page
1564  * faults preventing freezing. If the file system is already frozen, the
1565  * function waits until the file system is thawed.
1566  *
1567  * Since page fault freeze protection behaves as a lock, users have to preserve
1568  * ordering of freeze protection and other filesystem locks. It is advised to
1569  * put sb_start_pagefault() close to mmap_sem in lock ordering. Page fault
1570  * handling code implies lock dependency:
1571  *
1572  * mmap_sem
1573  *   -> sb_start_pagefault
1574  */
1575 static inline void sb_start_pagefault(struct super_block *sb)
1576 {
1577         __sb_start_write(sb, SB_FREEZE_PAGEFAULT, true);
1578 }
1579 
1580 /*
1581  * sb_start_intwrite - get write access to a superblock for internal fs purposes
1582  * @sb: the super we write to
1583  *
1584  * This is the third level of protection against filesystem freezing. It is
1585  * free for use by a filesystem. The only requirement is that it must rank
1586  * below sb_start_pagefault.
1587  *
1588  * For example filesystem can call sb_start_intwrite() when starting a
1589  * transaction which somewhat eases handling of freezing for internal sources
1590  * of filesystem changes (internal fs threads, discarding preallocation on file
1591  * close, etc.).
1592  */
1593 static inline void sb_start_intwrite(struct super_block *sb)
1594 {
1595         __sb_start_write(sb, SB_FREEZE_FS, true);
1596 }
1597 
1598 
1599 extern bool inode_owner_or_capable(const struct inode *inode);
1600 
1601 /*
1602  * VFS helper functions..
1603  */
1604 extern int vfs_create(struct inode *, struct dentry *, umode_t, bool);
1605 extern int vfs_mkdir(struct inode *, struct dentry *, umode_t);
1606 extern int vfs_mknod(struct inode *, struct dentry *, umode_t, dev_t);
1607 extern int vfs_symlink(struct inode *, struct dentry *, const char *);
1608 extern int vfs_link(struct dentry *, struct inode *, struct dentry *, struct inode **);
1609 extern int vfs_rmdir(struct inode *, struct dentry *);
1610 extern int vfs_unlink(struct inode *, struct dentry *, struct inode **);
1611 extern int vfs_rename(struct inode *, struct dentry *, struct inode *, struct dentry *, struct inode **, unsigned int);
1612 extern int vfs_whiteout(struct inode *, struct dentry *);
1613 
1614 extern struct dentry *vfs_tmpfile(struct dentry *dentry, umode_t mode,
1615                                   int open_flag);
1616 
1617 int vfs_mkobj(struct dentry *, umode_t,
1618                 int (*f)(struct dentry *, umode_t, void *),
1619                 void *);
1620 
1621 /*
1622  * VFS file helper functions.
1623  */
1624 extern void inode_init_owner(struct inode *inode, const struct inode *dir,
1625                         umode_t mode);
1626 extern bool may_open_dev(const struct path *path);
1627 /*
1628  * VFS FS_IOC_FIEMAP helper definitions.
1629  */
1630 struct fiemap_extent_info {
1631         unsigned int fi_flags;          /* Flags as passed from user */
1632         unsigned int fi_extents_mapped; /* Number of mapped extents */
1633         unsigned int fi_extents_max;    /* Size of fiemap_extent array */
1634         struct fiemap_extent __user *fi_extents_start; /* Start of
1635                                                         fiemap_extent array */
1636 };
1637 int fiemap_fill_next_extent(struct fiemap_extent_info *info, u64 logical,
1638                             u64 phys, u64 len, u32 flags);
1639 int fiemap_check_flags(struct fiemap_extent_info *fieinfo, u32 fs_flags);
1640 
1641 /*
1642  * File types
1643  *
1644  * NOTE! These match bits 12..15 of stat.st_mode
1645  * (ie "(i_mode >> 12) & 15").
1646  */
1647 #define DT_UNKNOWN      0
1648 #define DT_FIFO         1
1649 #define DT_CHR          2
1650 #define DT_DIR          4
1651 #define DT_BLK          6
1652 #define DT_REG          8
1653 #define DT_LNK          10
1654 #define DT_SOCK         12
1655 #define DT_WHT          14
1656 
1657 /*
1658  * This is the "filldir" function type, used by readdir() to let
1659  * the kernel specify what kind of dirent layout it wants to have.
1660  * This allows the kernel to read directories into kernel space or
1661  * to have different dirent layouts depending on the binary type.
1662  */
1663 struct dir_context;
1664 typedef int (*filldir_t)(struct dir_context *, const char *, int, loff_t, u64,
1665                          unsigned);
1666 
1667 struct dir_context {
1668         const filldir_t actor;
1669         loff_t pos;
1670 };
1671 
1672 struct block_device_operations;
1673 
1674 /* These macros are for out of kernel modules to test that
1675  * the kernel supports the unlocked_ioctl and compat_ioctl
1676  * fields in struct file_operations. */
1677 #define HAVE_COMPAT_IOCTL 1
1678 #define HAVE_UNLOCKED_IOCTL 1
1679 
1680 /*
1681  * These flags let !MMU mmap() govern direct device mapping vs immediate
1682  * copying more easily for MAP_PRIVATE, especially for ROM filesystems.
1683  *
1684  * NOMMU_MAP_COPY:      Copy can be mapped (MAP_PRIVATE)
1685  * NOMMU_MAP_DIRECT:    Can be mapped directly (MAP_SHARED)
1686  * NOMMU_MAP_READ:      Can be mapped for reading
1687  * NOMMU_MAP_WRITE:     Can be mapped for writing
1688  * NOMMU_MAP_EXEC:      Can be mapped for execution
1689  */
1690 #define NOMMU_MAP_COPY          0x00000001
1691 #define NOMMU_MAP_DIRECT        0x00000008
1692 #define NOMMU_MAP_READ          VM_MAYREAD
1693 #define NOMMU_MAP_WRITE         VM_MAYWRITE
1694 #define NOMMU_MAP_EXEC          VM_MAYEXEC
1695 
1696 #define NOMMU_VMFLAGS \
1697         (NOMMU_MAP_READ | NOMMU_MAP_WRITE | NOMMU_MAP_EXEC)
1698 
1699 
1700 struct iov_iter;
1701 
1702 struct file_operations {
1703         struct module *owner;
1704         loff_t (*llseek) (struct file *, loff_t, int);
1705         ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);
1706         ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
1707         ssize_t (*read_iter) (struct kiocb *, struct iov_iter *);
1708         ssize_t (*write_iter) (struct kiocb *, struct iov_iter *);
1709         int (*iterate) (struct file *, struct dir_context *);
1710         int (*iterate_shared) (struct file *, struct dir_context *);
1711         __poll_t (*poll) (struct file *, struct poll_table_struct *);
1712         long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
1713         long (*compat_ioctl) (struct file *, unsigned int, unsigned long);
1714         int (*mmap) (struct file *, struct vm_area_struct *);
1715         unsigned long mmap_supported_flags;
1716         int (*open) (struct inode *, struct file *);
1717         int (*flush) (struct file *, fl_owner_t id);
1718         int (*release) (struct inode *, struct file *);
1719         int (*fsync) (struct file *, loff_t, loff_t, int datasync);
1720         int (*fasync) (int, struct file *, int);
1721         int (*lock) (struct file *, int, struct file_lock *);
1722         ssize_t (*sendpage) (struct file *, struct page *, int, size_t, loff_t *, int);
1723         unsigned long (*get_unmapped_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
1724         int (*check_flags)(int);
1725         int (*flock) (struct file *, int, struct file_lock *);
1726         ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, loff_t *, size_t, unsigned int);
1727         ssize_t (*splice_read)(struct file *, loff_t *, struct pipe_inode_info *, size_t, unsigned int);
1728         int (*setlease)(struct file *, long, struct file_lock **, void **);
1729         long (*fallocate)(struct file *file, int mode, loff_t offset,
1730                           loff_t len);
1731         void (*show_fdinfo)(struct seq_file *m, struct file *f);
1732 #ifndef CONFIG_MMU
1733         unsigned (*mmap_capabilities)(struct file *);
1734 #endif
1735         ssize_t (*copy_file_range)(struct file *, loff_t, struct file *,
1736                         loff_t, size_t, unsigned int);
1737         int (*clone_file_range)(struct file *, loff_t, struct file *, loff_t,
1738                         u64);
1739         ssize_t (*dedupe_file_range)(struct file *, u64, u64, struct file *,
1740                         u64);
1741 } __randomize_layout;
1742 
1743 struct inode_operations {
1744         struct dentry * (*lookup) (struct inode *,struct dentry *, unsigned int);
1745         const char * (*get_link) (struct dentry *, struct inode *, struct delayed_call *);
1746         int (*permission) (struct inode *, int);
1747         struct posix_acl * (*get_acl)(struct inode *, int);
1748 
1749         int (*readlink) (struct dentry *, char __user *,int);
1750 
1751         int (*create) (struct inode *,struct dentry *, umode_t, bool);
1752         int (*link) (struct dentry *,struct inode *,struct dentry *);
1753         int (*unlink) (struct inode *,struct dentry *);
1754         int (*symlink) (struct inode *,struct dentry *,const char *);
1755         int (*mkdir) (struct inode *,struct dentry *,umode_t);
1756         int (*rmdir) (struct inode *,struct dentry *);
1757         int (*mknod) (struct inode *,struct dentry *,umode_t,dev_t);
1758         int (*rename) (struct inode *, struct dentry *,
1759                         struct inode *, struct dentry *, unsigned int);
1760         int (*setattr) (struct dentry *, struct iattr *);
1761         int (*getattr) (const struct path *, struct kstat *, u32, unsigned int);
1762         ssize_t (*listxattr) (struct dentry *, char *, size_t);
1763         int (*fiemap)(struct inode *, struct fiemap_extent_info *, u64 start,
1764                       u64 len);
1765         int (*update_time)(struct inode *, struct timespec *, int);
1766         int (*atomic_open)(struct inode *, struct dentry *,
1767                            struct file *, unsigned open_flag,
1768                            umode_t create_mode, int *opened);
1769         int (*tmpfile) (struct inode *, struct dentry *, umode_t);
1770         int (*set_acl)(struct inode *, struct posix_acl *, int);
1771 } ____cacheline_aligned;
1772 
1773 static inline ssize_t call_read_iter(struct file *file, struct kiocb *kio,
1774                                      struct iov_iter *iter)
1775 {
1776         return file->f_op->read_iter(kio, iter);
1777 }
1778 
1779 static inline ssize_t call_write_iter(struct file *file, struct kiocb *kio,
1780                                       struct iov_iter *iter)
1781 {
1782         return file->f_op->write_iter(kio, iter);
1783 }
1784 
1785 static inline int call_mmap(struct file *file, struct vm_area_struct *vma)
1786 {
1787         return file->f_op->mmap(file, vma);
1788 }
1789 
1790 ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector,
1791                               unsigned long nr_segs, unsigned long fast_segs,
1792                               struct iovec *fast_pointer,
1793                               struct iovec **ret_pointer);
1794 
1795 extern ssize_t __vfs_read(struct file *, char __user *, size_t, loff_t *);
1796 extern ssize_t vfs_read(struct file *, char __user *, size_t, loff_t *);
1797 extern ssize_t vfs_write(struct file *, const char __user *, size_t, loff_t *);
1798 extern ssize_t vfs_readv(struct file *, const struct iovec __user *,
1799                 unsigned long, loff_t *, rwf_t);
1800 extern ssize_t vfs_copy_file_range(struct file *, loff_t , struct file *,
1801                                    loff_t, size_t, unsigned int);
1802 extern int vfs_clone_file_prep_inodes(struct inode *inode_in, loff_t pos_in,
1803                                       struct inode *inode_out, loff_t pos_out,
1804                                       u64 *len, bool is_dedupe);
1805 extern int vfs_clone_file_range(struct file *file_in, loff_t pos_in,
1806                 struct file *file_out, loff_t pos_out, u64 len);
1807 extern int vfs_dedupe_file_range_compare(struct inode *src, loff_t srcoff,
1808                                          struct inode *dest, loff_t destoff,
1809                                          loff_t len, bool *is_same);
1810 extern int vfs_dedupe_file_range(struct file *file,
1811                                  struct file_dedupe_range *same);
1812 
1813 struct super_operations {
1814         struct inode *(*alloc_inode)(struct super_block *sb);
1815         void (*destroy_inode)(struct inode *);
1816 
1817         void (*dirty_inode) (struct inode *, int flags);
1818         int (*write_inode) (struct inode *, struct writeback_control *wbc);
1819         int (*drop_inode) (struct inode *);
1820         void (*evict_inode) (struct inode *);
1821         void (*put_super) (struct super_block *);
1822         int (*sync_fs)(struct super_block *sb, int wait);
1823         int (*freeze_super) (struct super_block *);
1824         int (*freeze_fs) (struct super_block *);
1825         int (*thaw_super) (struct super_block *);
1826         int (*unfreeze_fs) (struct super_block *);
1827         int (*statfs) (struct dentry *, struct kstatfs *);
1828         int (*remount_fs) (struct super_block *, int *, char *);
1829         void (*umount_begin) (struct super_block *);
1830 
1831         int (*show_options)(struct seq_file *, struct dentry *);
1832         int (*show_devname)(struct seq_file *, struct dentry *);
1833         int (*show_path)(struct seq_file *, struct dentry *);
1834         int (*show_stats)(struct seq_file *, struct dentry *);
1835 #ifdef CONFIG_QUOTA
1836         ssize_t (*quota_read)(struct super_block *, int, char *, size_t, loff_t);
1837         ssize_t (*quota_write)(struct super_block *, int, const char *, size_t, loff_t);
1838         struct dquot **(*get_dquots)(struct inode *);
1839 #endif
1840         int (*bdev_try_to_free_page)(struct super_block*, struct page*, gfp_t);
1841         long (*nr_cached_objects)(struct super_block *,
1842                                   struct shrink_control *);
1843         long (*free_cached_objects)(struct super_block *,
1844                                     struct shrink_control *);
1845 };
1846 
1847 /*
1848  * Inode flags - they have no relation to superblock flags now
1849  */
1850 #define S_SYNC          1       /* Writes are synced at once */
1851 #define S_NOATIME       2       /* Do not update access times */
1852 #define S_APPEND        4       /* Append-only file */
1853 #define S_IMMUTABLE     8       /* Immutable file */
1854 #define S_DEAD          16      /* removed, but still open directory */
1855 #define S_NOQUOTA       32      /* Inode is not counted to quota */
1856 #define S_DIRSYNC       64      /* Directory modifications are synchronous */
1857 #define S_NOCMTIME      128     /* Do not update file c/mtime */
1858 #define S_SWAPFILE      256     /* Do not truncate: swapon got its bmaps */
1859 #define S_PRIVATE       512     /* Inode is fs-internal */
1860 #define S_IMA           1024    /* Inode has an associated IMA struct */
1861 #define S_AUTOMOUNT     2048    /* Automount/referral quasi-directory */
1862 #define S_NOSEC         4096    /* no suid or xattr security attributes */
1863 #ifdef CONFIG_FS_DAX
1864 #define S_DAX           8192    /* Direct Access, avoiding the page cache */
1865 #else
1866 #define S_DAX           0       /* Make all the DAX code disappear */
1867 #endif
1868 #define S_ENCRYPTED     16384   /* Encrypted file (using fs/crypto/) */
1869 
1870 /*
1871  * Note that nosuid etc flags are inode-specific: setting some file-system
1872  * flags just means all the inodes inherit those flags by default. It might be
1873  * possible to override it selectively if you really wanted to with some
1874  * ioctl() that is not currently implemented.
1875  *
1876  * Exception: SB_RDONLY is always applied to the entire file system.
1877  *
1878  * Unfortunately, it is possible to change a filesystems flags with it mounted
1879  * with files in use.  This means that all of the inodes will not have their
1880  * i_flags updated.  Hence, i_flags no longer inherit the superblock mount
1881  * flags, so these have to be checked separately. -- rmk@arm.uk.linux.org
1882  */
1883 #define __IS_FLG(inode, flg)    ((inode)->i_sb->s_flags & (flg))
1884 
1885 static inline bool sb_rdonly(const struct super_block *sb) { return sb->s_flags & SB_RDONLY; }
1886 #define IS_RDONLY(inode)        sb_rdonly((inode)->i_sb)
1887 #define IS_SYNC(inode)          (__IS_FLG(inode, SB_SYNCHRONOUS) || \
1888                                         ((inode)->i_flags & S_SYNC))
1889 #define IS_DIRSYNC(inode)       (__IS_FLG(inode, SB_SYNCHRONOUS|SB_DIRSYNC) || \
1890                                         ((inode)->i_flags & (S_SYNC|S_DIRSYNC)))
1891 #define IS_MANDLOCK(inode)      __IS_FLG(inode, SB_MANDLOCK)
1892 #define IS_NOATIME(inode)       __IS_FLG(inode, SB_RDONLY|SB_NOATIME)
1893 #define IS_I_VERSION(inode)     __IS_FLG(inode, SB_I_VERSION)
1894 
1895 #define IS_NOQUOTA(inode)       ((inode)->i_flags & S_NOQUOTA)
1896 #define IS_APPEND(inode)        ((inode)->i_flags & S_APPEND)
1897 #define IS_IMMUTABLE(inode)     ((inode)->i_flags & S_IMMUTABLE)
1898 #define IS_POSIXACL(inode)      __IS_FLG(inode, SB_POSIXACL)
1899 
1900 #define IS_DEADDIR(inode)       ((inode)->i_flags & S_DEAD)
1901 #define IS_NOCMTIME(inode)      ((inode)->i_flags & S_NOCMTIME)
1902 #define IS_SWAPFILE(inode)      ((inode)->i_flags & S_SWAPFILE)
1903 #define IS_PRIVATE(inode)       ((inode)->i_flags & S_PRIVATE)
1904 #define IS_IMA(inode)           ((inode)->i_flags & S_IMA)
1905 #define IS_AUTOMOUNT(inode)     ((inode)->i_flags & S_AUTOMOUNT)
1906 #define IS_NOSEC(inode)         ((inode)->i_flags & S_NOSEC)
1907 #define IS_DAX(inode)           ((inode)->i_flags & S_DAX)
1908 #define IS_ENCRYPTED(inode)     ((inode)->i_flags & S_ENCRYPTED)
1909 
1910 #define IS_WHITEOUT(inode)      (S_ISCHR(inode->i_mode) && \
1911                                  (inode)->i_rdev == WHITEOUT_DEV)
1912 
1913 static inline bool HAS_UNMAPPED_ID(struct inode *inode)
1914 {
1915         return !uid_valid(inode->i_uid) || !gid_valid(inode->i_gid);
1916 }
1917 
1918 static inline enum rw_hint file_write_hint(struct file *file)
1919 {
1920         if (file->f_write_hint != WRITE_LIFE_NOT_SET)
1921                 return file->f_write_hint;
1922 
1923         return file_inode(file)->i_write_hint;
1924 }
1925 
1926 static inline int iocb_flags(struct file *file);
1927 
1928 static inline void init_sync_kiocb(struct kiocb *kiocb, struct file *filp)
1929 {
1930         *kiocb = (struct kiocb) {
1931                 .ki_filp = filp,
1932                 .ki_flags = iocb_flags(filp),
1933                 .ki_hint = file_write_hint(filp),
1934         };
1935 }
1936 
1937 /*
1938  * Inode state bits.  Protected by inode->i_lock
1939  *
1940  * Three bits determine the dirty state of the inode, I_DIRTY_SYNC,
1941  * I_DIRTY_DATASYNC and I_DIRTY_PAGES.
1942  *
1943  * Four bits define the lifetime of an inode.  Initially, inodes are I_NEW,
1944  * until that flag is cleared.  I_WILL_FREE, I_FREEING and I_CLEAR are set at
1945  * various stages of removing an inode.
1946  *
1947  * Two bits are used for locking and completion notification, I_NEW and I_SYNC.
1948  *
1949  * I_DIRTY_SYNC         Inode is dirty, but doesn't have to be written on
1950  *                      fdatasync().  i_atime is the usual cause.
1951  * I_DIRTY_DATASYNC     Data-related inode changes pending. We keep track of
1952  *                      these changes separately from I_DIRTY_SYNC so that we
1953  *                      don't have to write inode on fdatasync() when only
1954  *                      mtime has changed in it.
1955  * I_DIRTY_PAGES        Inode has dirty pages.  Inode itself may be clean.
1956  * I_NEW                Serves as both a mutex and completion notification.
1957  *                      New inodes set I_NEW.  If two processes both create
1958  *                      the same inode, one of them will release its inode and
1959  *                      wait for I_NEW to be released before returning.
1960  *                      Inodes in I_WILL_FREE, I_FREEING or I_CLEAR state can
1961  *                      also cause waiting on I_NEW, without I_NEW actually
1962  *                      being set.  find_inode() uses this to prevent returning
1963  *                      nearly-dead inodes.
1964  * I_WILL_FREE          Must be set when calling write_inode_now() if i_count
1965  *                      is zero.  I_FREEING must be set when I_WILL_FREE is
1966  *                      cleared.
1967  * I_FREEING            Set when inode is about to be freed but still has dirty
1968  *                      pages or buffers attached or the inode itself is still
1969  *                      dirty.
1970  * I_CLEAR              Added by clear_inode().  In this state the inode is
1971  *                      clean and can be destroyed.  Inode keeps I_FREEING.
1972  *
1973  *                      Inodes that are I_WILL_FREE, I_FREEING or I_CLEAR are
1974  *                      prohibited for many purposes.  iget() must wait for
1975  *                      the inode to be completely released, then create it
1976  *                      anew.  Other functions will just ignore such inodes,
1977  *                      if appropriate.  I_NEW is used for waiting.
1978  *
1979  * I_SYNC               Writeback of inode is running. The bit is set during
1980  *                      data writeback, and cleared with a wakeup on the bit
1981  *                      address once it is done. The bit is also used to pin
1982  *                      the inode in memory for flusher thread.
1983  *
1984  * I_REFERENCED         Marks the inode as recently references on the LRU list.
1985  *
1986  * I_DIO_WAKEUP         Never set.  Only used as a key for wait_on_bit().
1987  *
1988  * I_WB_SWITCH          Cgroup bdi_writeback switching in progress.  Used to
1989  *                      synchronize competing switching instances and to tell
1990  *                      wb stat updates to grab mapping->tree_lock.  See
1991  *                      inode_switch_wb_work_fn() for details.
1992  *
1993  * I_OVL_INUSE          Used by overlayfs to get exclusive ownership on upper
1994  *                      and work dirs among overlayfs mounts.
1995  *
1996  * Q: What is the difference between I_WILL_FREE and I_FREEING?
1997  */
1998 #define I_DIRTY_SYNC            (1 << 0)
1999 #define I_DIRTY_DATASYNC        (1 << 1)
2000 #define I_DIRTY_PAGES           (1 << 2)
2001 #define __I_NEW                 3
2002 #define I_NEW                   (1 << __I_NEW)
2003 #define I_WILL_FREE             (1 << 4)
2004 #define I_FREEING               (1 << 5)
2005 #define I_CLEAR                 (1 << 6)
2006 #define __I_SYNC                7
2007 #define I_SYNC                  (1 << __I_SYNC)
2008 #define I_REFERENCED            (1 << 8)
2009 #define __I_DIO_WAKEUP          9
2010 #define I_DIO_WAKEUP            (1 << __I_DIO_WAKEUP)
2011 #define I_LINKABLE              (1 << 10)
2012 #define I_DIRTY_TIME            (1 << 11)
2013 #define __I_DIRTY_TIME_EXPIRED  12
2014 #define I_DIRTY_TIME_EXPIRED    (1 << __I_DIRTY_TIME_EXPIRED)
2015 #define I_WB_SWITCH             (1 << 13)
2016 #define I_OVL_INUSE                     (1 << 14)
2017 
2018 #define I_DIRTY (I_DIRTY_SYNC | I_DIRTY_DATASYNC | I_DIRTY_PAGES)
2019 #define I_DIRTY_ALL (I_DIRTY | I_DIRTY_TIME)
2020 
2021 extern void __mark_inode_dirty(struct inode *, int);
2022 static inline void mark_inode_dirty(struct inode *inode)
2023 {
2024         __mark_inode_dirty(inode, I_DIRTY);
2025 }
2026 
2027 static inline void mark_inode_dirty_sync(struct inode *inode)
2028 {
2029         __mark_inode_dirty(inode, I_DIRTY_SYNC);
2030 }
2031 
2032 extern void inc_nlink(struct inode *inode);
2033 extern void drop_nlink(struct inode *inode);
2034 extern void clear_nlink(struct inode *inode);
2035 extern void set_nlink(struct inode *inode, unsigned int nlink);
2036 
2037 static inline void inode_inc_link_count(struct inode *inode)
2038 {
2039         inc_nlink(inode);
2040         mark_inode_dirty(inode);
2041 }
2042 
2043 static inline void inode_dec_link_count(struct inode *inode)
2044 {
2045         drop_nlink(inode);
2046         mark_inode_dirty(inode);
2047 }
2048 
2049 enum file_time_flags {
2050         S_ATIME = 1,
2051         S_MTIME = 2,
2052         S_CTIME = 4,
2053         S_VERSION = 8,
2054 };
2055 
2056 extern void touch_atime(const struct path *);
2057 static inline void file_accessed(struct file *file)
2058 {
2059         if (!(file->f_flags & O_NOATIME))
2060                 touch_atime(&file->f_path);
2061 }
2062 
2063 int sync_inode(struct inode *inode, struct writeback_control *wbc);
2064 int sync_inode_metadata(struct inode *inode, int wait);
2065 
2066 struct file_system_type {
2067         const char *name;
2068         int fs_flags;
2069 #define FS_REQUIRES_DEV         1 
2070 #define FS_BINARY_MOUNTDATA     2
2071 #define FS_HAS_SUBTYPE          4
2072 #define FS_USERNS_MOUNT         8       /* Can be mounted by userns root */
2073 #define FS_RENAME_DOES_D_MOVE   32768   /* FS will handle d_move() during rename() internally. */
2074         struct dentry *(*mount) (struct file_system_type *, int,
2075                        const char *, void *);
2076         void (*kill_sb) (struct super_block *);
2077         struct module *owner;
2078         struct file_system_type * next;
2079         struct hlist_head fs_supers;
2080 
2081         struct lock_class_key s_lock_key;
2082         struct lock_class_key s_umount_key;
2083         struct lock_class_key s_vfs_rename_key;
2084         struct lock_class_key s_writers_key[SB_FREEZE_LEVELS];
2085 
2086         struct lock_class_key i_lock_key;
2087         struct lock_class_key i_mutex_key;
2088         struct lock_class_key i_mutex_dir_key;
2089 };
2090 
2091 #define MODULE_ALIAS_FS(NAME) MODULE_ALIAS("fs-" NAME)
2092 
2093 extern struct dentry *mount_ns(struct file_system_type *fs_type,
2094         int flags, void *data, void *ns, struct user_namespace *user_ns,
2095         int (*fill_super)(struct super_block *, void *, int));
2096 #ifdef CONFIG_BLOCK
2097 extern struct dentry *mount_bdev(struct file_system_type *fs_type,
2098         int flags, const char *dev_name, void *data,
2099         int (*fill_super)(struct super_block *, void *, int));
2100 #else
2101 static inline struct dentry *mount_bdev(struct file_system_type *fs_type,
2102         int flags, const char *dev_name, void *data,
2103         int (*fill_super)(struct super_block *, void *, int))
2104 {
2105         return ERR_PTR(-ENODEV);
2106 }
2107 #endif
2108 extern struct dentry *mount_single(struct file_system_type *fs_type,
2109         int flags, void *data,
2110         int (*fill_super)(struct super_block *, void *, int));
2111 extern struct dentry *mount_nodev(struct file_system_type *fs_type,
2112         int flags, void *data,
2113         int (*fill_super)(struct super_block *, void *, int));
2114 extern struct dentry *mount_subtree(struct vfsmount *mnt, const char *path);
2115 void generic_shutdown_super(struct super_block *sb);
2116 #ifdef CONFIG_BLOCK
2117 void kill_block_super(struct super_block *sb);
2118 #else
2119 static inline void kill_block_super(struct super_block *sb)
2120 {
2121         BUG();
2122 }
2123 #endif
2124 void kill_anon_super(struct super_block *sb);
2125 void kill_litter_super(struct super_block *sb);
2126 void deactivate_super(struct super_block *sb);
2127 void deactivate_locked_super(struct super_block *sb);
2128 int set_anon_super(struct super_block *s, void *data);
2129 int get_anon_bdev(dev_t *);
2130 void free_anon_bdev(dev_t);
2131 struct super_block *sget_userns(struct file_system_type *type,
2132                         int (*test)(struct super_block *,void *),
2133                         int (*set)(struct super_block *,void *),
2134                         int flags, struct user_namespace *user_ns,
2135                         void *data);
2136 struct super_block *sget(struct file_system_type *type,
2137                         int (*test)(struct super_block *,void *),
2138                         int (*set)(struct super_block *,void *),
2139                         int flags, void *data);
2140 extern struct dentry *mount_pseudo_xattr(struct file_system_type *, char *,
2141                                          const struct super_operations *ops,
2142                                          const struct xattr_handler **xattr,
2143                                          const struct dentry_operations *dops,
2144                                          unsigned long);
2145 
2146 static inline struct dentry *
2147 mount_pseudo(struct file_system_type *fs_type, char *name,
2148              const struct super_operations *ops,
2149              const struct dentry_operations *dops, unsigned long magic)
2150 {
2151         return mount_pseudo_xattr(fs_type, name, ops, NULL, dops, magic);
2152 }
2153 
2154 /* Alas, no aliases. Too much hassle with bringing module.h everywhere */
2155 #define fops_get(fops) \
2156         (((fops) && try_module_get((fops)->owner) ? (fops) : NULL))
2157 #define fops_put(fops) \
2158         do { if (fops) module_put((fops)->owner); } while(0)
2159 /*
2160  * This one is to be used *ONLY* from ->open() instances.
2161  * fops must be non-NULL, pinned down *and* module dependencies
2162  * should be sufficient to pin the caller down as well.
2163  */
2164 #define replace_fops(f, fops) \
2165         do {    \
2166                 struct file *__file = (f); \
2167                 fops_put(__file->f_op); \
2168                 BUG_ON(!(__file->f_op = (fops))); \
2169         } while(0)
2170 
2171 extern int register_filesystem(struct file_system_type *);
2172 extern int unregister_filesystem(struct file_system_type *);
2173 extern struct vfsmount *kern_mount_data(struct file_system_type *, void *data);
2174 #define kern_mount(type) kern_mount_data(type, NULL)
2175 extern void kern_unmount(struct vfsmount *mnt);
2176 extern int may_umount_tree(struct vfsmount *);
2177 extern int may_umount(struct vfsmount *);
2178 extern long do_mount(const char *, const char __user *,
2179                      const char *, unsigned long, void *);
2180 extern struct vfsmount *collect_mounts(const struct path *);
2181 extern void drop_collected_mounts(struct vfsmount *);
2182 extern int iterate_mounts(int (*)(struct vfsmount *, void *), void *,
2183                           struct vfsmount *);
2184 extern int vfs_statfs(const struct path *, struct kstatfs *);
2185 extern int user_statfs(const char __user *, struct kstatfs *);
2186 extern int fd_statfs(int, struct kstatfs *);
2187 extern int freeze_super(struct super_block *super);
2188 extern int thaw_super(struct super_block *super);
2189 extern bool our_mnt(struct vfsmount *mnt);
2190 extern __printf(2, 3)
2191 int super_setup_bdi_name(struct super_block *sb, char *fmt, ...);
2192 extern int super_setup_bdi(struct super_block *sb);
2193 
2194 extern int current_umask(void);
2195 
2196 extern void ihold(struct inode * inode);
2197 extern void iput(struct inode *);
2198 extern int generic_update_time(struct inode *, struct timespec *, int);
2199 
2200 /* /sys/fs */
2201 extern struct kobject *fs_kobj;
2202 
2203 #define MAX_RW_COUNT (INT_MAX & PAGE_MASK)
2204 
2205 #ifdef CONFIG_MANDATORY_FILE_LOCKING
2206 extern int locks_mandatory_locked(struct file *);
2207 extern int locks_mandatory_area(struct inode *, struct file *, loff_t, loff_t, unsigned char);
2208 
2209 /*
2210  * Candidates for mandatory locking have the setgid bit set
2211  * but no group execute bit -  an otherwise meaningless combination.
2212  */
2213 
2214 static inline int __mandatory_lock(struct inode *ino)
2215 {
2216         return (ino->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID;
2217 }
2218 
2219 /*
2220  * ... and these candidates should be on SB_MANDLOCK mounted fs,
2221  * otherwise these will be advisory locks
2222  */
2223 
2224 static inline int mandatory_lock(struct inode *ino)
2225 {
2226         return IS_MANDLOCK(ino) && __mandatory_lock(ino);
2227 }
2228 
2229 static inline int locks_verify_locked(struct file *file)
2230 {
2231         if (mandatory_lock(locks_inode(file)))
2232                 return locks_mandatory_locked(file);
2233         return 0;
2234 }
2235 
2236 static inline int locks_verify_truncate(struct inode *inode,
2237                                     struct file *f,
2238                                     loff_t size)
2239 {
2240         if (!inode->i_flctx || !mandatory_lock(inode))
2241                 return 0;
2242 
2243         if (size < inode->i_size) {
2244                 return locks_mandatory_area(inode, f, size, inode->i_size - 1,
2245                                 F_WRLCK);
2246         } else {
2247                 return locks_mandatory_area(inode, f, inode->i_size, size - 1,
2248                                 F_WRLCK);
2249         }
2250 }
2251 
2252 #else /* !CONFIG_MANDATORY_FILE_LOCKING */
2253 
2254 static inline int locks_mandatory_locked(struct file *file)
2255 {
2256         return 0;
2257 }
2258 
2259 static inline int locks_mandatory_area(struct inode *inode, struct file *filp,
2260                                        loff_t start, loff_t end, unsigned char type)
2261 {
2262         return 0;
2263 }
2264 
2265 static inline int __mandatory_lock(struct inode *inode)
2266 {
2267         return 0;
2268 }
2269 
2270 static inline int mandatory_lock(struct inode *inode)
2271 {
2272         return 0;
2273 }
2274 
2275 static inline int locks_verify_locked(struct file *file)
2276 {
2277         return 0;
2278 }
2279 
2280 static inline int locks_verify_truncate(struct inode *inode, struct file *filp,
2281                                         size_t size)
2282 {
2283         return 0;
2284 }
2285 
2286 #endif /* CONFIG_MANDATORY_FILE_LOCKING */
2287 
2288 
2289 #ifdef CONFIG_FILE_LOCKING
2290 static inline int break_lease(struct inode *inode, unsigned int mode)
2291 {
2292         /*
2293          * Since this check is lockless, we must ensure that any refcounts
2294          * taken are done before checking i_flctx->flc_lease. Otherwise, we
2295          * could end up racing with tasks trying to set a new lease on this
2296          * file.
2297          */
2298         smp_mb();
2299         if (inode->i_flctx && !list_empty_careful(&inode->i_flctx->flc_lease))
2300                 return __break_lease(inode, mode, FL_LEASE);
2301         return 0;
2302 }
2303 
2304 static inline int break_deleg(struct inode *inode, unsigned int mode)
2305 {
2306         /*
2307          * Since this check is lockless, we must ensure that any refcounts
2308          * taken are done before checking i_flctx->flc_lease. Otherwise, we
2309          * could end up racing with tasks trying to set a new lease on this
2310          * file.
2311          */
2312         smp_mb();
2313         if (inode->i_flctx && !list_empty_careful(&inode->i_flctx->flc_lease))
2314                 return __break_lease(inode, mode, FL_DELEG);
2315         return 0;
2316 }
2317 
2318 static inline int try_break_deleg(struct inode *inode, struct inode **delegated_inode)
2319 {
2320         int ret;
2321 
2322         ret = break_deleg(inode, O_WRONLY|O_NONBLOCK);
2323         if (ret == -EWOULDBLOCK && delegated_inode) {
2324                 *delegated_inode = inode;
2325                 ihold(inode);
2326         }
2327         return ret;
2328 }
2329 
2330 static inline int break_deleg_wait(struct inode **delegated_inode)
2331 {
2332         int ret;
2333 
2334         ret = break_deleg(*delegated_inode, O_WRONLY);
2335         iput(*delegated_inode);
2336         *delegated_inode = NULL;
2337         return ret;
2338 }
2339 
2340 static inline int break_layout(struct inode *inode, bool wait)
2341 {
2342         smp_mb();
2343         if (inode->i_flctx && !list_empty_careful(&inode->i_flctx->flc_lease))
2344                 return __break_lease(inode,
2345                                 wait ? O_WRONLY : O_WRONLY | O_NONBLOCK,
2346                                 FL_LAYOUT);
2347         return 0;
2348 }
2349 
2350 #else /* !CONFIG_FILE_LOCKING */
2351 static inline int break_lease(struct inode *inode, unsigned int mode)
2352 {
2353         return 0;
2354 }
2355 
2356 static inline int break_deleg(struct inode *inode, unsigned int mode)
2357 {
2358         return 0;
2359 }
2360 
2361 static inline int try_break_deleg(struct inode *inode, struct inode **delegated_inode)
2362 {
2363         return 0;
2364 }
2365 
2366 static inline int break_deleg_wait(struct inode **delegated_inode)
2367 {
2368         BUG();
2369         return 0;
2370 }
2371 
2372 static inline int break_layout(struct inode *inode, bool wait)
2373 {
2374         return 0;
2375 }
2376 
2377 #endif /* CONFIG_FILE_LOCKING */
2378 
2379 /* fs/open.c */
2380 struct audit_names;
2381 struct filename {
2382         const char              *name;  /* pointer to actual string */
2383         const __user char       *uptr;  /* original userland pointer */
2384         struct audit_names      *aname;
2385         int                     refcnt;
2386         const char              iname[];
2387 };
2388 
2389 extern long vfs_truncate(const struct path *, loff_t);
2390 extern int do_truncate(struct dentry *, loff_t start, unsigned int time_attrs,
2391                        struct file *filp);
2392 extern int vfs_fallocate(struct file *file, int mode, loff_t offset,
2393                         loff_t len);
2394 extern long do_sys_open(int dfd, const char __user *filename, int flags,
2395                         umode_t mode);
2396 extern struct file *file_open_name(struct filename *, int, umode_t);
2397 extern struct file *filp_open(const char *, int, umode_t);
2398 extern struct file *file_open_root(struct dentry *, struct vfsmount *,
2399                                    const char *, int, umode_t);
2400 extern struct file * dentry_open(const struct path *, int, const struct cred *);
2401 extern int filp_close(struct file *, fl_owner_t id);
2402 
2403 extern struct filename *getname_flags(const char __user *, int, int *);
2404 extern struct filename *getname(const char __user *);
2405 extern struct filename *getname_kernel(const char *);
2406 extern void putname(struct filename *name);
2407 
2408 enum {
2409         FILE_CREATED = 1,
2410         FILE_OPENED = 2
2411 };
2412 extern int finish_open(struct file *file, struct dentry *dentry,
2413                         int (*open)(struct inode *, struct file *),
2414                         int *opened);
2415 extern int finish_no_open(struct file *file, struct dentry *dentry);
2416 
2417 /* fs/ioctl.c */
2418 
2419 extern int ioctl_preallocate(struct file *filp, void __user *argp);
2420 
2421 /* fs/dcache.c */
2422 extern void __init vfs_caches_init_early(void);
2423 extern void __init vfs_caches_init(void);
2424 
2425 extern struct kmem_cache *names_cachep;
2426 
2427 #define __getname()             kmem_cache_alloc(names_cachep, GFP_KERNEL)
2428 #define __putname(name)         kmem_cache_free(names_cachep, (void *)(name))
2429 
2430 #ifdef CONFIG_BLOCK
2431 extern int register_blkdev(unsigned int, const char *);
2432 extern void unregister_blkdev(unsigned int, const char *);
2433 extern void bdev_unhash_inode(dev_t dev);
2434 extern struct block_device *bdget(dev_t);
2435 extern struct block_device *bdgrab(struct block_device *bdev);
2436 extern void bd_set_size(struct block_device *, loff_t size);
2437 extern void bd_forget(struct inode *inode);
2438 extern void bdput(struct block_device *);
2439 extern void invalidate_bdev(struct block_device *);
2440 extern void iterate_bdevs(void (*)(struct block_device *, void *), void *);
2441 extern int sync_blockdev(struct block_device *bdev);
2442 extern void kill_bdev(struct block_device *);
2443 extern struct super_block *freeze_bdev(struct block_device *);
2444 extern void emergency_thaw_all(void);
2445 extern int thaw_bdev(struct block_device *bdev, struct super_block *sb);
2446 extern int fsync_bdev(struct block_device *);
2447 
2448 extern struct super_block *blockdev_superblock;
2449 
2450 static inline bool sb_is_blkdev_sb(struct super_block *sb)
2451 {
2452         return sb == blockdev_superblock;
2453 }
2454 #else
2455 static inline void bd_forget(struct inode *inode) {}
2456 static inline int sync_blockdev(struct block_device *bdev) { return 0; }
2457 static inline void kill_bdev(struct block_device *bdev) {}
2458 static inline void invalidate_bdev(struct block_device *bdev) {}
2459 
2460 static inline struct super_block *freeze_bdev(struct block_device *sb)
2461 {
2462         return NULL;
2463 }
2464 
2465 static inline int thaw_bdev(struct block_device *bdev, struct super_block *sb)
2466 {
2467         return 0;
2468 }
2469 
2470 static inline void iterate_bdevs(void (*f)(struct block_device *, void *), void *arg)
2471 {
2472 }
2473 
2474 static inline bool sb_is_blkdev_sb(struct super_block *sb)
2475 {
2476         return false;
2477 }
2478 #endif
2479 extern int sync_filesystem(struct super_block *);
2480 extern const struct file_operations def_blk_fops;
2481 extern const struct file_operations def_chr_fops;
2482 #ifdef CONFIG_BLOCK
2483 extern int ioctl_by_bdev(struct block_device *, unsigned, unsigned long);
2484 extern int blkdev_ioctl(struct block_device *, fmode_t, unsigned, unsigned long);
2485 extern long compat_blkdev_ioctl(struct file *, unsigned, unsigned long);
2486 extern int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder);
2487 extern struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
2488                                                void *holder);
2489 extern struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode,
2490                                               void *holder);
2491 extern void blkdev_put(struct block_device *bdev, fmode_t mode);
2492 extern int __blkdev_reread_part(struct block_device *bdev);
2493 extern int blkdev_reread_part(struct block_device *bdev);
2494 
2495 #ifdef CONFIG_SYSFS
2496 extern int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk);
2497 extern void bd_unlink_disk_holder(struct block_device *bdev,
2498                                   struct gendisk *disk);
2499 #else
2500 static inline int bd_link_disk_holder(struct block_device *bdev,
2501                                       struct gendisk *disk)
2502 {
2503         return 0;
2504 }
2505 static inline void bd_unlink_disk_holder(struct block_device *bdev,
2506                                          struct gendisk *disk)
2507 {
2508 }
2509 #endif
2510 #endif
2511 
2512 /* fs/char_dev.c */
2513 #define CHRDEV_MAJOR_MAX 512
2514 /* Marks the bottom of the first segment of free char majors */
2515 #define CHRDEV_MAJOR_DYN_END 234
2516 /* Marks the top and bottom of the second segment of free char majors */
2517 #define CHRDEV_MAJOR_DYN_EXT_START 511
2518 #define CHRDEV_MAJOR_DYN_EXT_END 384
2519 
2520 extern int alloc_chrdev_region(dev_t *, unsigned, unsigned, const char *);
2521 extern int register_chrdev_region(dev_t, unsigned, const char *);
2522 extern int __register_chrdev(unsigned int major, unsigned int baseminor,
2523                              unsigned int count, const char *name,
2524                              const struct file_operations *fops);
2525 extern void __unregister_chrdev(unsigned int major, unsigned int baseminor,
2526                                 unsigned int count, const char *name);
2527 extern void unregister_chrdev_region(dev_t, unsigned);
2528 extern void chrdev_show(struct seq_file *,off_t);
2529 
2530 static inline int register_chrdev(unsigned int major, const char *name,
2531                                   const struct file_operations *fops)
2532 {
2533         return __register_chrdev(major, 0, 256, name, fops);
2534 }
2535 
2536 static inline void unregister_chrdev(unsigned int major, const char *name)
2537 {
2538         __unregister_chrdev(major, 0, 256, name);
2539 }
2540 
2541 /* fs/block_dev.c */
2542 #define BDEVNAME_SIZE   32      /* Largest string for a blockdev identifier */
2543 #define BDEVT_SIZE      10      /* Largest string for MAJ:MIN for blkdev */
2544 
2545 #ifdef CONFIG_BLOCK
2546 #define BLKDEV_MAJOR_MAX        512
2547 extern const char *__bdevname(dev_t, char *buffer);
2548 extern const char *bdevname(struct block_device *bdev, char *buffer);
2549 extern struct block_device *lookup_bdev(const char *);
2550 extern void blkdev_show(struct seq_file *,off_t);
2551 
2552 #else
2553 #define BLKDEV_MAJOR_MAX        0
2554 #endif
2555 
2556 extern void init_special_inode(struct inode *, umode_t, dev_t);
2557 
2558 /* Invalid inode operations -- fs/bad_inode.c */
2559 extern void make_bad_inode(struct inode *);
2560 extern bool is_bad_inode(struct inode *);
2561 
2562 #ifdef CONFIG_BLOCK
2563 extern void check_disk_size_change(struct gendisk *disk,
2564                                    struct block_device *bdev);
2565 extern int revalidate_disk(struct gendisk *);
2566 extern int check_disk_change(struct block_device *);
2567 extern int __invalidate_device(struct block_device *, bool);
2568 extern int invalidate_partition(struct gendisk *, int);
2569 #endif
2570 unsigned long invalidate_mapping_pages(struct address_space *mapping,
2571                                         pgoff_t start, pgoff_t end);
2572 
2573 static inline void invalidate_remote_inode(struct inode *inode)
2574 {
2575         if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
2576             S_ISLNK(inode->i_mode))
2577                 invalidate_mapping_pages(inode->i_mapping, 0, -1);
2578 }
2579 extern int invalidate_inode_pages2(struct address_space *mapping);
2580 extern int invalidate_inode_pages2_range(struct address_space *mapping,
2581                                          pgoff_t start, pgoff_t end);
2582 extern int write_inode_now(struct inode *, int);
2583 extern int filemap_fdatawrite(struct address_space *);
2584 extern int filemap_flush(struct address_space *);
2585 extern int filemap_fdatawait_keep_errors(struct address_space *mapping);
2586 extern int filemap_fdatawait_range(struct address_space *, loff_t lstart,
2587                                    loff_t lend);
2588 
2589 static inline int filemap_fdatawait(struct address_space *mapping)
2590 {
2591         return filemap_fdatawait_range(mapping, 0, LLONG_MAX);
2592 }
2593 
2594 extern bool filemap_range_has_page(struct address_space *, loff_t lstart,
2595                                   loff_t lend);
2596 extern int __must_check file_fdatawait_range(struct file *file, loff_t lstart,
2597                                                 loff_t lend);
2598 extern int filemap_write_and_wait(struct address_space *mapping);
2599 extern int filemap_write_and_wait_range(struct address_space *mapping,
2600                                         loff_t lstart, loff_t lend);
2601 extern int __filemap_fdatawrite_range(struct address_space *mapping,
2602                                 loff_t start, loff_t end, int sync_mode);
2603 extern int filemap_fdatawrite_range(struct address_space *mapping,
2604                                 loff_t start, loff_t end);
2605 extern int filemap_check_errors(struct address_space *mapping);
2606 extern void __filemap_set_wb_err(struct address_space *mapping, int err);
2607 
2608 extern int __must_check file_fdatawait_range(struct file *file, loff_t lstart,
2609                                                 loff_t lend);
2610 extern int __must_check file_check_and_advance_wb_err(struct file *file);
2611 extern int __must_check file_write_and_wait_range(struct file *file,
2612                                                 loff_t start, loff_t end);
2613 
2614 static inline int file_write_and_wait(struct file *file)
2615 {
2616         return file_write_and_wait_range(file, 0, LLONG_MAX);
2617 }
2618 
2619 /**
2620  * filemap_set_wb_err - set a writeback error on an address_space
2621  * @mapping: mapping in which to set writeback error
2622  * @err: error to be set in mapping
2623  *
2624  * When writeback fails in some way, we must record that error so that
2625  * userspace can be informed when fsync and the like are called.  We endeavor
2626  * to report errors on any file that was open at the time of the error.  Some
2627  * internal callers also need to know when writeback errors have occurred.
2628  *
2629  * When a writeback error occurs, most filesystems will want to call
2630  * filemap_set_wb_err to record the error in the mapping so that it will be
2631  * automatically reported whenever fsync is called on the file.
2632  */
2633 static inline void filemap_set_wb_err(struct address_space *mapping, int err)
2634 {
2635         /* Fastpath for common case of no error */
2636         if (unlikely(err))
2637                 __filemap_set_wb_err(mapping, err);
2638 }
2639 
2640 /**
2641  * filemap_check_wb_error - has an error occurred since the mark was sampled?
2642  * @mapping: mapping to check for writeback errors
2643  * @since: previously-sampled errseq_t
2644  *
2645  * Grab the errseq_t value from the mapping, and see if it has changed "since"
2646  * the given value was sampled.
2647  *
2648  * If it has then report the latest error set, otherwise return 0.
2649  */
2650 static inline int filemap_check_wb_err(struct address_space *mapping,
2651                                         errseq_t since)
2652 {
2653         return errseq_check(&mapping->wb_err, since);
2654 }
2655 
2656 /**
2657  * filemap_sample_wb_err - sample the current errseq_t to test for later errors
2658  * @mapping: mapping to be sampled
2659  *
2660  * Writeback errors are always reported relative to a particular sample point
2661  * in the past. This function provides those sample points.
2662  */
2663 static inline errseq_t filemap_sample_wb_err(struct address_space *mapping)
2664 {
2665         return errseq_sample(&mapping->wb_err);
2666 }
2667 
2668 extern int vfs_fsync_range(struct file *file, loff_t start, loff_t end,
2669                            int datasync);
2670 extern int vfs_fsync(struct file *file, int datasync);
2671 
2672 /*
2673  * Sync the bytes written if this was a synchronous write.  Expect ki_pos
2674  * to already be updated for the write, and will return either the amount
2675  * of bytes passed in, or an error if syncing the file failed.
2676  */
2677 static inline ssize_t generic_write_sync(struct kiocb *iocb, ssize_t count)
2678 {
2679         if (iocb->ki_flags & IOCB_DSYNC) {
2680                 int ret = vfs_fsync_range(iocb->ki_filp,
2681                                 iocb->ki_pos - count, iocb->ki_pos - 1,
2682                                 (iocb->ki_flags & IOCB_SYNC) ? 0 : 1);
2683                 if (ret)
2684                         return ret;
2685         }
2686 
2687         return count;
2688 }
2689 
2690 extern void emergency_sync(void);
2691 extern void emergency_remount(void);
2692 #ifdef CONFIG_BLOCK
2693 extern sector_t bmap(struct inode *, sector_t);
2694 #endif
2695 extern int notify_change(struct dentry *, struct iattr *, struct inode **);
2696 extern int inode_permission(struct inode *, int);
2697 extern int generic_permission(struct inode *, int);
2698 extern int __check_sticky(struct inode *dir, struct inode *inode);
2699 
2700 static inline bool execute_ok(struct inode *inode)
2701 {
2702         return (inode->i_mode & S_IXUGO) || S_ISDIR(inode->i_mode);
2703 }
2704 
2705 static inline void file_start_write(struct file *file)
2706 {
2707         if (!S_ISREG(file_inode(file)->i_mode))
2708                 return;
2709         __sb_start_write(file_inode(file)->i_sb, SB_FREEZE_WRITE, true);
2710 }
2711 
2712 static inline bool file_start_write_trylock(struct file *file)
2713 {
2714         if (!S_ISREG(file_inode(file)->i_mode))
2715                 return true;
2716         return __sb_start_write(file_inode(file)->i_sb, SB_FREEZE_WRITE, false);
2717 }
2718 
2719 static inline void file_end_write(struct file *file)
2720 {
2721         if (!S_ISREG(file_inode(file)->i_mode))
2722                 return;
2723         __sb_end_write(file_inode(file)->i_sb, SB_FREEZE_WRITE);
2724 }
2725 
2726 static inline int do_clone_file_range(struct file *file_in, loff_t pos_in,
2727                                       struct file *file_out, loff_t pos_out,
2728                                       u64 len)
2729 {
2730         int ret;
2731 
2732         file_start_write(file_out);
2733         ret = vfs_clone_file_range(file_in, pos_in, file_out, pos_out, len);
2734         file_end_write(file_out);
2735 
2736         return ret;
2737 }
2738 
2739 /*
2740  * get_write_access() gets write permission for a file.
2741  * put_write_access() releases this write permission.
2742  * This is used for regular files.
2743  * We cannot support write (and maybe mmap read-write shared) accesses and
2744  * MAP_DENYWRITE mmappings simultaneously. The i_writecount field of an inode
2745  * can have the following values:
2746  * 0: no writers, no VM_DENYWRITE mappings
2747  * < 0: (-i_writecount) vm_area_structs with VM_DENYWRITE set exist
2748  * > 0: (i_writecount) users are writing to the file.
2749  *
2750  * Normally we operate on that counter with atomic_{inc,dec} and it's safe
2751  * except for the cases where we don't hold i_writecount yet. Then we need to
2752  * use {get,deny}_write_access() - these functions check the sign and refuse
2753  * to do the change if sign is wrong.
2754  */
2755 static inline int get_write_access(struct inode *inode)
2756 {
2757         return atomic_inc_unless_negative(&inode->i_writecount) ? 0 : -ETXTBSY;
2758 }
2759 static inline int deny_write_access(struct file *file)
2760 {
2761         struct inode *inode = file_inode(file);
2762         return atomic_dec_unless_positive(&inode->i_writecount) ? 0 : -ETXTBSY;
2763 }
2764 static inline void put_write_access(struct inode * inode)
2765 {
2766         atomic_dec(&inode->i_writecount);
2767 }
2768 static inline void allow_write_access(struct file *file)
2769 {
2770         if (file)
2771                 atomic_inc(&file_inode(file)->i_writecount);
2772 }
2773 static inline bool inode_is_open_for_write(const struct inode *inode)
2774 {
2775         return atomic_read(&inode->i_writecount) > 0;
2776 }
2777 
2778 #ifdef CONFIG_IMA
2779 static inline void i_readcount_dec(struct inode *inode)
2780 {
2781         BUG_ON(!atomic_read(&inode->i_readcount));
2782         atomic_dec(&inode->i_readcount);
2783 }
2784 static inline void i_readcount_inc(struct inode *inode)
2785 {
2786         atomic_inc(&inode->i_readcount);
2787 }
2788 #else
2789 static inline void i_readcount_dec(struct inode *inode)
2790 {
2791         return;
2792 }
2793 static inline void i_readcount_inc(struct inode *inode)
2794 {
2795         return;
2796 }
2797 #endif
2798 extern int do_pipe_flags(int *, int);
2799 
2800 #define __kernel_read_file_id(id) \
2801         id(UNKNOWN, unknown)            \
2802         id(FIRMWARE, firmware)          \
2803         id(FIRMWARE_PREALLOC_BUFFER, firmware)  \
2804         id(MODULE, kernel-module)               \
2805         id(KEXEC_IMAGE, kexec-image)            \
2806         id(KEXEC_INITRAMFS, kexec-initramfs)    \
2807         id(POLICY, security-policy)             \
2808         id(X509_CERTIFICATE, x509-certificate)  \
2809         id(MAX_ID, )
2810 
2811 #define __fid_enumify(ENUM, dummy) READING_ ## ENUM,
2812 #define __fid_stringify(dummy, str) #str,
2813 
2814 enum kernel_read_file_id {
2815         __kernel_read_file_id(__fid_enumify)
2816 };
2817 
2818 static const char * const kernel_read_file_str[] = {
2819         __kernel_read_file_id(__fid_stringify)
2820 };
2821 
2822 static inline const char *kernel_read_file_id_str(enum kernel_read_file_id id)
2823 {
2824         if ((unsigned)id >= READING_MAX_ID)
2825                 return kernel_read_file_str[READING_UNKNOWN];
2826 
2827         return kernel_read_file_str[id];
2828 }
2829 
2830 extern int kernel_read_file(struct file *, void **, loff_t *, loff_t,
2831                             enum kernel_read_file_id);
2832 extern int kernel_read_file_from_path(const char *, void **, loff_t *, loff_t,
2833                                       enum kernel_read_file_id);
2834 extern int kernel_read_file_from_fd(int, void **, loff_t *, loff_t,
2835                                     enum kernel_read_file_id);
2836 extern ssize_t kernel_read(struct file *, void *, size_t, loff_t *);
2837 extern ssize_t kernel_write(struct file *, const void *, size_t, loff_t *);
2838 extern ssize_t __kernel_write(struct file *, const void *, size_t, loff_t *);
2839 extern struct file * open_exec(const char *);
2840  
2841 /* fs/dcache.c -- generic fs support functions */
2842 extern bool is_subdir(struct dentry *, struct dentry *);
2843 extern bool path_is_under(const struct path *, const struct path *);
2844 
2845 extern char *file_path(struct file *, char *, int);
2846 
2847 #include <linux/err.h>
2848 
2849 /* needed for stackable file system support */
2850 extern loff_t default_llseek(struct file *file, loff_t offset, int whence);
2851 
2852 extern loff_t vfs_llseek(struct file *file, loff_t offset, int whence);
2853 
2854 extern int inode_init_always(struct super_block *, struct inode *);
2855 extern void inode_init_once(struct inode *);
2856 extern void address_space_init_once(struct address_space *mapping);
2857 extern struct inode * igrab(struct inode *);
2858 extern ino_t iunique(struct super_block *, ino_t);
2859 extern int inode_needs_sync(struct inode *inode);
2860 extern int generic_delete_inode(struct inode *inode);
2861 static inline int generic_drop_inode(struct inode *inode)
2862 {
2863         return !inode->i_nlink || inode_unhashed(inode);
2864 }
2865 
2866 extern struct inode *ilookup5_nowait(struct super_block *sb,
2867                 unsigned long hashval, int (*test)(struct inode *, void *),
2868                 void *data);
2869 extern struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
2870                 int (*test)(struct inode *, void *), void *data);
2871 extern struct inode *ilookup(struct super_block *sb, unsigned long ino);
2872 
2873 extern struct inode * iget5_locked(struct super_block *, unsigned long, int (*test)(struct inode *, void *), int (*set)(struct inode *, void *), void *);
2874 extern struct inode * iget_locked(struct super_block *, unsigned long);
2875 extern struct inode *find_inode_nowait(struct super_block *,
2876                                        unsigned long,
2877                                        int (*match)(struct inode *,
2878                                                     unsigned long, void *),
2879                                        void *data);
2880 extern int insert_inode_locked4(struct inode *, unsigned long, int (*test)(struct inode *, void *), void *);
2881 extern int insert_inode_locked(struct inode *);
2882 #ifdef CONFIG_DEBUG_LOCK_ALLOC
2883 extern void lockdep_annotate_inode_mutex_key(struct inode *inode);
2884 #else
2885 static inline void lockdep_annotate_inode_mutex_key(struct inode *inode) { };
2886 #endif
2887 extern void unlock_new_inode(struct inode *);
2888 extern unsigned int get_next_ino(void);
2889 extern void evict_inodes(struct super_block *sb);
2890 
2891 extern void __iget(struct inode * inode);
2892 extern void iget_failed(struct inode *);
2893 extern void clear_inode(struct inode *);
2894 extern void __destroy_inode(struct inode *);
2895 extern struct inode *new_inode_pseudo(struct super_block *sb);
2896 extern struct inode *new_inode(struct super_block *sb);
2897 extern void free_inode_nonrcu(struct inode *inode);
2898 extern int should_remove_suid(struct dentry *);
2899 extern int file_remove_privs(struct file *);
2900 
2901 extern void __insert_inode_hash(struct inode *, unsigned long hashval);
2902 static inline void insert_inode_hash(struct inode *inode)
2903 {
2904         __insert_inode_hash(inode, inode->i_ino);
2905 }
2906 
2907 extern void __remove_inode_hash(struct inode *);
2908 static inline void remove_inode_hash(struct inode *inode)
2909 {
2910         if (!inode_unhashed(inode) && !hlist_fake(&inode->i_hash))
2911                 __remove_inode_hash(inode);
2912 }
2913 
2914 extern void inode_sb_list_add(struct inode *inode);
2915 
2916 #ifdef CONFIG_BLOCK
2917 extern int bdev_read_only(struct block_device *);
2918 #endif
2919 extern int set_blocksize(struct block_device *, int);
2920 extern int sb_set_blocksize(struct super_block *, int);
2921 extern int sb_min_blocksize(struct super_block *, int);
2922 
2923 extern int generic_file_mmap(struct file *, struct vm_area_struct *);
2924 extern int generic_file_readonly_mmap(struct file *, struct vm_area_struct *);
2925 extern ssize_t generic_write_checks(struct kiocb *, struct iov_iter *);
2926 extern ssize_t generic_file_read_iter(struct kiocb *, struct iov_iter *);
2927 extern ssize_t __generic_file_write_iter(struct kiocb *, struct iov_iter *);
2928 extern ssize_t generic_file_write_iter(struct kiocb *, struct iov_iter *);
2929 extern ssize_t generic_file_direct_write(struct kiocb *, struct iov_iter *);
2930 extern ssize_t generic_perform_write(struct file *, struct iov_iter *, loff_t);
2931 
2932 ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos,
2933                 rwf_t flags);
2934 ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos,
2935                 rwf_t flags);
2936 
2937 /* fs/block_dev.c */
2938 extern ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to);
2939 extern ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from);
2940 extern int blkdev_fsync(struct file *filp, loff_t start, loff_t end,
2941                         int datasync);
2942 extern void block_sync_page(struct page *page);
2943 
2944 /* fs/splice.c */
2945 extern ssize_t generic_file_splice_read(struct file *, loff_t *,
2946                 struct pipe_inode_info *, size_t, unsigned int);
2947 extern ssize_t iter_file_splice_write(struct pipe_inode_info *,
2948                 struct file *, loff_t *, size_t, unsigned int);
2949 extern ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe,
2950                 struct file *out, loff_t *, size_t len, unsigned int flags);
2951 extern long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
2952                 loff_t *opos, size_t len, unsigned int flags);
2953 
2954 
2955 extern void
2956 file_ra_state_init(struct file_ra_state *ra, struct address_space *mapping);
2957 extern loff_t noop_llseek(struct file *file, loff_t offset, int whence);
2958 extern loff_t no_llseek(struct file *file, loff_t offset, int whence);
2959 extern loff_t vfs_setpos(struct file *file, loff_t offset, loff_t maxsize);
2960 extern loff_t generic_file_llseek(struct file *file, loff_t offset, int whence);
2961 extern loff_t generic_file_llseek_size(struct file *file, loff_t offset,
2962                 int whence, loff_t maxsize, loff_t eof);
2963 extern loff_t fixed_size_llseek(struct file *file, loff_t offset,
2964                 int whence, loff_t size);
2965 extern loff_t no_seek_end_llseek_size(struct file *, loff_t, int, loff_t);
2966 extern loff_t no_seek_end_llseek(struct file *, loff_t, int);
2967 extern int generic_file_open(struct inode * inode, struct file * filp);
2968 extern int nonseekable_open(struct inode * inode, struct file * filp);
2969 
2970 #ifdef CONFIG_BLOCK
2971 typedef void (dio_submit_t)(struct bio *bio, struct inode *inode,
2972                             loff_t file_offset);
2973 
2974 enum {
2975         /* need locking between buffered and direct access */
2976         DIO_LOCKING     = 0x01,
2977 
2978         /* filesystem does not support filling holes */
2979         DIO_SKIP_HOLES  = 0x02,
2980 
2981         /* filesystem can handle aio writes beyond i_size */
2982         DIO_ASYNC_EXTEND = 0x04,
2983 
2984         /* inode/fs/bdev does not need truncate protection */
2985         DIO_SKIP_DIO_COUNT = 0x08,
2986 };
2987 
2988 void dio_end_io(struct bio *bio);
2989 void dio_warn_stale_pagecache(struct file *filp);
2990 
2991 ssize_t __blockdev_direct_IO(struct kiocb *iocb, struct inode *inode,
2992                              struct block_device *bdev, struct iov_iter *iter,
2993                              get_block_t get_block,
2994                              dio_iodone_t end_io, dio_submit_t submit_io,
2995                              int flags);
2996 
2997 static inline ssize_t blockdev_direct_IO(struct kiocb *iocb,
2998                                          struct inode *inode,
2999                                          struct iov_iter *iter,
3000                                          get_block_t get_block)
3001 {
3002         return __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev, iter,
3003                         get_block, NULL, NULL, DIO_LOCKING | DIO_SKIP_HOLES);
3004 }
3005 #endif
3006 
3007 void inode_dio_wait(struct inode *inode);
3008 
3009 /*
3010  * inode_dio_begin - signal start of a direct I/O requests
3011  * @inode: inode the direct I/O happens on
3012  *
3013  * This is called once we've finished processing a direct I/O request,
3014  * and is used to wake up callers waiting for direct I/O to be quiesced.
3015  */
3016 static inline void inode_dio_begin(struct inode *inode)
3017 {
3018         atomic_inc(&inode->i_dio_count);
3019 }
3020 
3021 /*
3022  * inode_dio_end - signal finish of a direct I/O requests
3023  * @inode: inode the direct I/O happens on
3024  *
3025  * This is called once we've finished processing a direct I/O request,
3026  * and is used to wake up callers waiting for direct I/O to be quiesced.
3027  */
3028 static inline void inode_dio_end(struct inode *inode)
3029 {
3030         if (atomic_dec_and_test(&inode->i_dio_count))
3031                 wake_up_bit(&inode->i_state, __I_DIO_WAKEUP);
3032 }
3033 
3034 extern void inode_set_flags(struct inode *inode, unsigned int flags,
3035                             unsigned int mask);
3036 
3037 extern const struct file_operations generic_ro_fops;
3038 
3039 #define special_file(m) (S_ISCHR(m)||S_ISBLK(m)||S_ISFIFO(m)||S_ISSOCK(m))
3040 
3041 extern int readlink_copy(char __user *, int, const char *);
3042 extern int page_readlink(struct dentry *, char __user *, int);
3043 extern const char *page_get_link(struct dentry *, struct inode *,
3044                                  struct delayed_call *);
3045 extern void page_put_link(void *);
3046 extern int __page_symlink(struct inode *inode, const char *symname, int len,
3047                 int nofs);
3048 extern int page_symlink(struct inode *inode, const char *symname, int len);
3049 extern const struct inode_operations page_symlink_inode_operations;
3050 extern void kfree_link(void *);
3051 extern void generic_fillattr(struct inode *, struct kstat *);
3052 extern int vfs_getattr_nosec(const struct path *, struct kstat *, u32, unsigned int);
3053 extern int vfs_getattr(const struct path *, struct kstat *, u32, unsigned int);
3054 void __inode_add_bytes(struct inode *inode, loff_t bytes);
3055 void inode_add_bytes(struct inode *inode, loff_t bytes);
3056 void __inode_sub_bytes(struct inode *inode, loff_t bytes);
3057 void inode_sub_bytes(struct inode *inode, loff_t bytes);
3058 static inline loff_t __inode_get_bytes(struct inode *inode)
3059 {
3060         return (((loff_t)inode->i_blocks) << 9) + inode->i_bytes;
3061 }
3062 loff_t inode_get_bytes(struct inode *inode);
3063 void inode_set_bytes(struct inode *inode, loff_t bytes);
3064 const char *simple_get_link(struct dentry *, struct inode *,
3065                             struct delayed_call *);
3066 extern const struct inode_operations simple_symlink_inode_operations;
3067 
3068 extern int iterate_dir(struct file *, struct dir_context *);
3069 
3070 extern int vfs_statx(int, const char __user *, int, struct kstat *, u32);
3071 extern int vfs_statx_fd(unsigned int, struct kstat *, u32, unsigned int);
3072 
3073 static inline int vfs_stat(const char __user *filename, struct kstat *stat)
3074 {
3075         return vfs_statx(AT_FDCWD, filename, AT_NO_AUTOMOUNT,
3076                          stat, STATX_BASIC_STATS);
3077 }
3078 static inline int vfs_lstat(const char __user *name, struct kstat *stat)
3079 {
3080         return vfs_statx(AT_FDCWD, name, AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT,
3081                          stat, STATX_BASIC_STATS);
3082 }
3083 static inline int vfs_fstatat(int dfd, const char __user *filename,
3084                               struct kstat *stat, int flags)
3085 {
3086         return vfs_statx(dfd, filename, flags | AT_NO_AUTOMOUNT,
3087                          stat, STATX_BASIC_STATS);
3088 }
3089 static inline int vfs_fstat(int fd, struct kstat *stat)
3090 {
3091         return vfs_statx_fd(fd, stat, STATX_BASIC_STATS, 0);
3092 }
3093 
3094 
3095 extern const char *vfs_get_link(struct dentry *, struct delayed_call *);
3096 extern int vfs_readlink(struct dentry *, char __user *, int);
3097 
3098 extern int __generic_block_fiemap(struct inode *inode,
3099                                   struct fiemap_extent_info *fieinfo,
3100                                   loff_t start, loff_t len,
3101                                   get_block_t *get_block);
3102 extern int generic_block_fiemap(struct inode *inode,
3103                                 struct fiemap_extent_info *fieinfo, u64 start,
3104                                 u64 len, get_block_t *get_block);
3105 
3106 extern struct file_system_type *get_filesystem(struct file_system_type *fs);
3107 extern void put_filesystem(struct file_system_type *fs);
3108 extern struct file_system_type *get_fs_type(const char *name);
3109 extern struct super_block *get_super(struct block_device *);
3110 extern struct super_block *get_super_thawed(struct block_device *);
3111 extern struct super_block *get_super_exclusive_thawed(struct block_device *bdev);
3112 extern struct super_block *get_active_super(struct block_device *bdev);
3113 extern void drop_super(struct super_block *sb);
3114 extern void drop_super_exclusive(struct super_block *sb);
3115 extern void iterate_supers(void (*)(struct super_block *, void *), void *);
3116 extern void iterate_supers_type(struct file_system_type *,
3117                                 void (*)(struct super_block *, void *), void *);
3118 
3119 extern int dcache_dir_open(struct inode *, struct file *);
3120 extern int dcache_dir_close(struct inode *, struct file *);
3121 extern loff_t dcache_dir_lseek(struct file *, loff_t, int);
3122 extern int dcache_readdir(struct file *, struct dir_context *);
3123 extern int simple_setattr(struct dentry *, struct iattr *);
3124 extern int simple_getattr(const struct path *, struct kstat *, u32, unsigned int);
3125 extern int simple_statfs(struct dentry *, struct kstatfs *);
3126 extern int simple_open(struct inode *inode, struct file *file);
3127 extern int simple_link(struct dentry *, struct inode *, struct dentry *);
3128 extern int simple_unlink(struct inode *, struct dentry *);
3129 extern int simple_rmdir(struct inode *, struct dentry *);
3130 extern int simple_rename(struct inode *, struct dentry *,
3131                          struct inode *, struct dentry *, unsigned int);
3132 extern int noop_fsync(struct file *, loff_t, loff_t, int);
3133 extern int simple_empty(struct dentry *);
3134 extern int simple_readpage(struct file *file, struct page *page);
3135 extern int simple_write_begin(struct file *file, struct address_space *mapping,
3136                         loff_t pos, unsigned len, unsigned flags,
3137                         struct page **pagep, void **fsdata);
3138 extern int simple_write_end(struct file *file, struct address_space *mapping,
3139                         loff_t pos, unsigned len, unsigned copied,
3140                         struct page *page, void *fsdata);
3141 extern int always_delete_dentry(const struct dentry *);
3142 extern struct inode *alloc_anon_inode(struct super_block *);
3143 extern int simple_nosetlease(struct file *, long, struct file_lock **, void **);
3144 extern const struct dentry_operations simple_dentry_operations;
3145 
3146 extern struct dentry *simple_lookup(struct inode *, struct dentry *, unsigned int flags);
3147 extern ssize_t generic_read_dir(struct file *, char __user *, size_t, loff_t *);
3148 extern const struct file_operations simple_dir_operations;
3149 extern const struct inode_operations simple_dir_inode_operations;
3150 extern void make_empty_dir_inode(struct inode *inode);
3151 extern bool is_empty_dir_inode(struct inode *inode);
3152 struct tree_descr { const char *name; const struct file_operations *ops; int mode; };
3153 struct dentry *d_alloc_name(struct dentry *, const char *);
3154 extern int simple_fill_super(struct super_block *, unsigned long,
3155                              const struct tree_descr *);
3156 extern int simple_pin_fs(struct file_system_type *, struct vfsmount **mount, int *count);
3157 extern void simple_release_fs(struct vfsmount **mount, int *count);
3158 
3159 extern ssize_t simple_read_from_buffer(void __user *to, size_t count,
3160                         loff_t *ppos, const void *from, size_t available);
3161 extern ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos,
3162                 const void __user *from, size_t count);
3163 
3164 extern int __generic_file_fsync(struct file *, loff_t, loff_t, int);
3165 extern int generic_file_fsync(struct file *, loff_t, loff_t, int);
3166 
3167 extern int generic_check_addressable(unsigned, u64);
3168 
3169 #ifdef CONFIG_MIGRATION
3170 extern int buffer_migrate_page(struct address_space *,
3171                                 struct page *, struct page *,
3172                                 enum migrate_mode);
3173 #else
3174 #define buffer_migrate_page NULL
3175 #endif
3176 
3177 extern int setattr_prepare(struct dentry *, struct iattr *);
3178 extern int inode_newsize_ok(const struct inode *, loff_t offset);
3179 extern void setattr_copy(struct inode *inode, const struct iattr *attr);
3180 
3181 extern int file_update_time(struct file *file);
3182 
3183 static inline bool io_is_direct(struct file *filp)
3184 {
3185         return (filp->f_flags & O_DIRECT) || IS_DAX(filp->f_mapping->host);
3186 }
3187 
3188 static inline bool vma_is_dax(struct vm_area_struct *vma)
3189 {
3190         return vma->vm_file && IS_DAX(vma->vm_file->f_mapping->host);
3191 }
3192 
3193 static inline bool vma_is_fsdax(struct vm_area_struct *vma)
3194 {
3195         struct inode *inode;
3196 
3197         if (!vma->vm_file)
3198                 return false;
3199         if (!vma_is_dax(vma))
3200                 return false;
3201         inode = file_inode(vma->vm_file);
3202         if (S_ISCHR(inode->i_mode))
3203                 return false; /* device-dax */
3204         return true;
3205 }
3206 
3207 static inline int iocb_flags(struct file *file)
3208 {
3209         int res = 0;
3210         if (file->f_flags & O_APPEND)
3211                 res |= IOCB_APPEND;
3212         if (io_is_direct(file))
3213                 res |= IOCB_DIRECT;
3214         if ((file->f_flags & O_DSYNC) || IS_SYNC(file->f_mapping->host))
3215                 res |= IOCB_DSYNC;
3216         if (file->f_flags & __O_SYNC)
3217                 res |= IOCB_SYNC;
3218         return res;
3219 }
3220 
3221 static inline int kiocb_set_rw_flags(struct kiocb *ki, rwf_t flags)
3222 {
3223         if (unlikely(flags & ~RWF_SUPPORTED))
3224                 return -EOPNOTSUPP;
3225 
3226         if (flags & RWF_NOWAIT) {
3227                 if (!(ki->ki_filp->f_mode & FMODE_NOWAIT))
3228                         return -EOPNOTSUPP;
3229                 ki->ki_flags |= IOCB_NOWAIT;
3230         }
3231         if (flags & RWF_HIPRI)
3232                 ki->ki_flags |= IOCB_HIPRI;
3233         if (flags & RWF_DSYNC)
3234                 ki->ki_flags |= IOCB_DSYNC;
3235         if (flags & RWF_SYNC)
3236                 ki->ki_flags |= (IOCB_DSYNC | IOCB_SYNC);
3237         if (flags & RWF_APPEND)
3238                 ki->ki_flags |= IOCB_APPEND;
3239         return 0;
3240 }
3241 
3242 static inline ino_t parent_ino(struct dentry *dentry)
3243 {
3244         ino_t res;
3245 
3246         /*
3247          * Don't strictly need d_lock here? If the parent ino could change
3248          * then surely we'd have a deeper race in the caller?
3249          */
3250         spin_lock(&dentry->d_lock);
3251         res = dentry->d_parent->d_inode->i_ino;
3252         spin_unlock(&dentry->d_lock);
3253         return res;
3254 }
3255 
3256 /* Transaction based IO helpers */
3257 
3258 /*
3259  * An argresp is stored in an allocated page and holds the
3260  * size of the argument or response, along with its content
3261  */
3262 struct simple_transaction_argresp {
3263         ssize_t size;
3264         char data[0];
3265 };
3266 
3267 #define SIMPLE_TRANSACTION_LIMIT (PAGE_SIZE - sizeof(struct simple_transaction_argresp))
3268 
3269 char *simple_transaction_get(struct file *file, const char __user *buf,
3270                                 size_t size);
3271 ssize_t simple_transaction_read(struct file *file, char __user *buf,
3272                                 size_t size, loff_t *pos);
3273 int simple_transaction_release(struct inode *inode, struct file *file);
3274 
3275 void simple_transaction_set(struct file *file, size_t n);
3276 
3277 /*
3278  * simple attribute files
3279  *
3280  * These attributes behave similar to those in sysfs:
3281  *
3282  * Writing to an attribute immediately sets a value, an open file can be
3283  * written to multiple times.
3284  *
3285  * Reading from an attribute creates a buffer from the value that might get
3286  * read with multiple read calls. When the attribute has been read
3287  * completely, no further read calls are possible until the file is opened
3288  * again.
3289  *
3290  * All attributes contain a text representation of a numeric value
3291  * that are accessed with the get() and set() functions.
3292  */
3293 #define DEFINE_SIMPLE_ATTRIBUTE(__fops, __get, __set, __fmt)            \
3294 static int __fops ## _open(struct inode *inode, struct file *file)      \
3295 {                                                                       \
3296         __simple_attr_check_format(__fmt, 0ull);                        \
3297         return simple_attr_open(inode, file, __get, __set, __fmt);      \
3298 }                                                                       \
3299 static const struct file_operations __fops = {                          \
3300         .owner   = THIS_MODULE,                                         \
3301         .open    = __fops ## _open,                                     \
3302         .release = simple_attr_release,                                 \
3303         .read    = simple_attr_read,                                    \
3304         .write   = simple_attr_write,                                   \
3305         .llseek  = generic_file_llseek,                                 \
3306 }
3307 
3308 static inline __printf(1, 2)
3309 void __simple_attr_check_format(const char *fmt, ...)
3310 {
3311         /* don't do anything, just let the compiler check the arguments; */
3312 }
3313 
3314 int simple_attr_open(struct inode *inode, struct file *file,
3315                      int (*get)(void *, u64 *), int (*set)(void *, u64),
3316                      const char *fmt);
3317 int simple_attr_release(struct inode *inode, struct file *file);
3318 ssize_t simple_attr_read(struct file *file, char __user *buf,
3319                          size_t len, loff_t *ppos);
3320 ssize_t simple_attr_write(struct file *file, const char __user *buf,
3321                           size_t len, loff_t *ppos);
3322 
3323 struct ctl_table;
3324 int proc_nr_files(struct ctl_table *table, int write,
3325                   void __user *buffer, size_t *lenp, loff_t *ppos);
3326 int proc_nr_dentry(struct ctl_table *table, int write,
3327                   void __user *buffer, size_t *lenp, loff_t *ppos);
3328 int proc_nr_inodes(struct ctl_table *table, int write,
3329                    void __user *buffer, size_t *lenp, loff_t *ppos);
3330 int __init get_filesystem_list(char *buf);
3331 
3332 #define __FMODE_EXEC            ((__force int) FMODE_EXEC)
3333 #define __FMODE_NONOTIFY        ((__force int) FMODE_NONOTIFY)
3334 
3335 #define ACC_MODE(x) ("\004\002\006\006"[(x)&O_ACCMODE])
3336 #define OPEN_FMODE(flag) ((__force fmode_t)(((flag + 1) & O_ACCMODE) | \
3337                                             (flag & __FMODE_NONOTIFY)))
3338 
3339 static inline bool is_sxid(umode_t mode)
3340 {
3341         return (mode & S_ISUID) || ((mode & S_ISGID) && (mode & S_IXGRP));
3342 }
3343 
3344 static inline int check_sticky(struct inode *dir, struct inode *inode)
3345 {
3346         if (!(dir->i_mode & S_ISVTX))
3347                 return 0;
3348 
3349         return __check_sticky(dir, inode);
3350 }
3351 
3352 static inline void inode_has_no_xattr(struct inode *inode)
3353 {
3354         if (!is_sxid(inode->i_mode) && (inode->i_sb->s_flags & SB_NOSEC))
3355                 inode->i_flags |= S_NOSEC;
3356 }
3357 
3358 static inline bool is_root_inode(struct inode *inode)
3359 {
3360         return inode == inode->i_sb->s_root->d_inode;
3361 }
3362 
3363 static inline bool dir_emit(struct dir_context *ctx,
3364                             const char *name, int namelen,
3365                             u64 ino, unsigned type)
3366 {
3367         return ctx->actor(ctx, name, namelen, ctx->pos, ino, type) == 0;
3368 }
3369 static inline bool dir_emit_dot(struct file *file, struct dir_context *ctx)
3370 {
3371         return ctx->actor(ctx, ".", 1, ctx->pos,
3372                           file->f_path.dentry->d_inode->i_ino, DT_DIR) == 0;
3373 }
3374 static inline bool dir_emit_dotdot(struct file *file, struct dir_context *ctx)
3375 {
3376         return ctx->actor(ctx, "..", 2, ctx->pos,
3377                           parent_ino(file->f_path.dentry), DT_DIR) == 0;
3378 }
3379 static inline bool dir_emit_dots(struct file *file, struct dir_context *ctx)
3380 {
3381         if (ctx->pos == 0) {
3382                 if (!dir_emit_dot(file, ctx))
3383                         return false;
3384                 ctx->pos = 1;
3385         }
3386         if (ctx->pos == 1) {
3387                 if (!dir_emit_dotdot(file, ctx))
3388                         return false;
3389                 ctx->pos = 2;
3390         }
3391         return true;
3392 }
3393 static inline bool dir_relax(struct inode *inode)
3394 {
3395         inode_unlock(inode);
3396         inode_lock(inode);
3397         return !IS_DEADDIR(inode);
3398 }
3399 
3400 static inline bool dir_relax_shared(struct inode *inode)
3401 {
3402         inode_unlock_shared(inode);
3403         inode_lock_shared(inode);
3404         return !IS_DEADDIR(inode);
3405 }
3406 
3407 extern bool path_noexec(const struct path *path);
3408 extern void inode_nohighmem(struct inode *inode);
3409 
3410 #endif /* _LINUX_FS_H */
3411 

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