Version:  2.0.40 2.2.26 2.4.37 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10

Linux/include/linux/fs.h

  1 #ifndef _LINUX_FS_H
  2 #define _LINUX_FS_H
  3 
  4 #include <linux/linkage.h>
  5 #include <linux/wait.h>
  6 #include <linux/kdev_t.h>
  7 #include <linux/dcache.h>
  8 #include <linux/path.h>
  9 #include <linux/stat.h>
 10 #include <linux/cache.h>
 11 #include <linux/list.h>
 12 #include <linux/list_lru.h>
 13 #include <linux/llist.h>
 14 #include <linux/radix-tree.h>
 15 #include <linux/rbtree.h>
 16 #include <linux/init.h>
 17 #include <linux/pid.h>
 18 #include <linux/bug.h>
 19 #include <linux/mutex.h>
 20 #include <linux/rwsem.h>
 21 #include <linux/capability.h>
 22 #include <linux/semaphore.h>
 23 #include <linux/fiemap.h>
 24 #include <linux/rculist_bl.h>
 25 #include <linux/atomic.h>
 26 #include <linux/shrinker.h>
 27 #include <linux/migrate_mode.h>
 28 #include <linux/uidgid.h>
 29 #include <linux/lockdep.h>
 30 #include <linux/percpu-rwsem.h>
 31 #include <linux/workqueue.h>
 32 #include <linux/percpu-rwsem.h>
 33 #include <linux/delayed_call.h>
 34 
 35 #include <asm/byteorder.h>
 36 #include <uapi/linux/fs.h>
 37 
 38 struct backing_dev_info;
 39 struct bdi_writeback;
 40 struct bio;
 41 struct export_operations;
 42 struct hd_geometry;
 43 struct iovec;
 44 struct kiocb;
 45 struct kobject;
 46 struct pipe_inode_info;
 47 struct poll_table_struct;
 48 struct kstatfs;
 49 struct vm_area_struct;
 50 struct vfsmount;
 51 struct cred;
 52 struct swap_info_struct;
 53 struct seq_file;
 54 struct workqueue_struct;
 55 struct iov_iter;
 56 struct fscrypt_info;
 57 struct fscrypt_operations;
 58 
 59 extern void __init inode_init(void);
 60 extern void __init inode_init_early(void);
 61 extern void __init files_init(void);
 62 extern void __init files_maxfiles_init(void);
 63 
 64 extern struct files_stat_struct files_stat;
 65 extern unsigned long get_max_files(void);
 66 extern unsigned int sysctl_nr_open;
 67 extern struct inodes_stat_t inodes_stat;
 68 extern int leases_enable, lease_break_time;
 69 extern int sysctl_protected_symlinks;
 70 extern int sysctl_protected_hardlinks;
 71 
 72 struct buffer_head;
 73 typedef int (get_block_t)(struct inode *inode, sector_t iblock,
 74                         struct buffer_head *bh_result, int create);
 75 typedef int (dio_iodone_t)(struct kiocb *iocb, loff_t offset,
 76                         ssize_t bytes, void *private);
 77 
 78 #define MAY_EXEC                0x00000001
 79 #define MAY_WRITE               0x00000002
 80 #define MAY_READ                0x00000004
 81 #define MAY_APPEND              0x00000008
 82 #define MAY_ACCESS              0x00000010
 83 #define MAY_OPEN                0x00000020
 84 #define MAY_CHDIR               0x00000040
 85 /* called from RCU mode, don't block */
 86 #define MAY_NOT_BLOCK           0x00000080
 87 
 88 /*
 89  * flags in file.f_mode.  Note that FMODE_READ and FMODE_WRITE must correspond
 90  * to O_WRONLY and O_RDWR via the strange trick in __dentry_open()
 91  */
 92 
 93 /* file is open for reading */
 94 #define FMODE_READ              ((__force fmode_t)0x1)
 95 /* file is open for writing */
 96 #define FMODE_WRITE             ((__force fmode_t)0x2)
 97 /* file is seekable */
 98 #define FMODE_LSEEK             ((__force fmode_t)0x4)
 99 /* file can be accessed using pread */
100 #define FMODE_PREAD             ((__force fmode_t)0x8)
101 /* file can be accessed using pwrite */
102 #define FMODE_PWRITE            ((__force fmode_t)0x10)
103 /* File is opened for execution with sys_execve / sys_uselib */
104 #define FMODE_EXEC              ((__force fmode_t)0x20)
105 /* File is opened with O_NDELAY (only set for block devices) */
106 #define FMODE_NDELAY            ((__force fmode_t)0x40)
107 /* File is opened with O_EXCL (only set for block devices) */
108 #define FMODE_EXCL              ((__force fmode_t)0x80)
109 /* File is opened using open(.., 3, ..) and is writeable only for ioctls
110    (specialy hack for floppy.c) */
111 #define FMODE_WRITE_IOCTL       ((__force fmode_t)0x100)
112 /* 32bit hashes as llseek() offset (for directories) */
113 #define FMODE_32BITHASH         ((__force fmode_t)0x200)
114 /* 64bit hashes as llseek() offset (for directories) */
115 #define FMODE_64BITHASH         ((__force fmode_t)0x400)
116 
117 /*
118  * Don't update ctime and mtime.
119  *
120  * Currently a special hack for the XFS open_by_handle ioctl, but we'll
121  * hopefully graduate it to a proper O_CMTIME flag supported by open(2) soon.
122  */
123 #define FMODE_NOCMTIME          ((__force fmode_t)0x800)
124 
125 /* Expect random access pattern */
126 #define FMODE_RANDOM            ((__force fmode_t)0x1000)
127 
128 /* File is huge (eg. /dev/kmem): treat loff_t as unsigned */
129 #define FMODE_UNSIGNED_OFFSET   ((__force fmode_t)0x2000)
130 
131 /* File is opened with O_PATH; almost nothing can be done with it */
132 #define FMODE_PATH              ((__force fmode_t)0x4000)
133 
134 /* File needs atomic accesses to f_pos */
135 #define FMODE_ATOMIC_POS        ((__force fmode_t)0x8000)
136 /* Write access to underlying fs */
137 #define FMODE_WRITER            ((__force fmode_t)0x10000)
138 /* Has read method(s) */
139 #define FMODE_CAN_READ          ((__force fmode_t)0x20000)
140 /* Has write method(s) */
141 #define FMODE_CAN_WRITE         ((__force fmode_t)0x40000)
142 
143 /* File was opened by fanotify and shouldn't generate fanotify events */
144 #define FMODE_NONOTIFY          ((__force fmode_t)0x4000000)
145 
146 /*
147  * Flag for rw_copy_check_uvector and compat_rw_copy_check_uvector
148  * that indicates that they should check the contents of the iovec are
149  * valid, but not check the memory that the iovec elements
150  * points too.
151  */
152 #define CHECK_IOVEC_ONLY -1
153 
154 /*
155  * Attribute flags.  These should be or-ed together to figure out what
156  * has been changed!
157  */
158 #define ATTR_MODE       (1 << 0)
159 #define ATTR_UID        (1 << 1)
160 #define ATTR_GID        (1 << 2)
161 #define ATTR_SIZE       (1 << 3)
162 #define ATTR_ATIME      (1 << 4)
163 #define ATTR_MTIME      (1 << 5)
164 #define ATTR_CTIME      (1 << 6)
165 #define ATTR_ATIME_SET  (1 << 7)
166 #define ATTR_MTIME_SET  (1 << 8)
167 #define ATTR_FORCE      (1 << 9) /* Not a change, but a change it */
168 #define ATTR_ATTR_FLAG  (1 << 10)
169 #define ATTR_KILL_SUID  (1 << 11)
170 #define ATTR_KILL_SGID  (1 << 12)
171 #define ATTR_FILE       (1 << 13)
172 #define ATTR_KILL_PRIV  (1 << 14)
173 #define ATTR_OPEN       (1 << 15) /* Truncating from open(O_TRUNC) */
174 #define ATTR_TIMES_SET  (1 << 16)
175 #define ATTR_TOUCH      (1 << 17)
176 
177 /*
178  * Whiteout is represented by a char device.  The following constants define the
179  * mode and device number to use.
180  */
181 #define WHITEOUT_MODE 0
182 #define WHITEOUT_DEV 0
183 
184 /*
185  * This is the Inode Attributes structure, used for notify_change().  It
186  * uses the above definitions as flags, to know which values have changed.
187  * Also, in this manner, a Filesystem can look at only the values it cares
188  * about.  Basically, these are the attributes that the VFS layer can
189  * request to change from the FS layer.
190  *
191  * Derek Atkins <warlord@MIT.EDU> 94-10-20
192  */
193 struct iattr {
194         unsigned int    ia_valid;
195         umode_t         ia_mode;
196         kuid_t          ia_uid;
197         kgid_t          ia_gid;
198         loff_t          ia_size;
199         struct timespec ia_atime;
200         struct timespec ia_mtime;
201         struct timespec ia_ctime;
202 
203         /*
204          * Not an attribute, but an auxiliary info for filesystems wanting to
205          * implement an ftruncate() like method.  NOTE: filesystem should
206          * check for (ia_valid & ATTR_FILE), and not for (ia_file != NULL).
207          */
208         struct file     *ia_file;
209 };
210 
211 /*
212  * Includes for diskquotas.
213  */
214 #include <linux/quota.h>
215 
216 /*
217  * Maximum number of layers of fs stack.  Needs to be limited to
218  * prevent kernel stack overflow
219  */
220 #define FILESYSTEM_MAX_STACK_DEPTH 2
221 
222 /** 
223  * enum positive_aop_returns - aop return codes with specific semantics
224  *
225  * @AOP_WRITEPAGE_ACTIVATE: Informs the caller that page writeback has
226  *                          completed, that the page is still locked, and
227  *                          should be considered active.  The VM uses this hint
228  *                          to return the page to the active list -- it won't
229  *                          be a candidate for writeback again in the near
230  *                          future.  Other callers must be careful to unlock
231  *                          the page if they get this return.  Returned by
232  *                          writepage(); 
233  *
234  * @AOP_TRUNCATED_PAGE: The AOP method that was handed a locked page has
235  *                      unlocked it and the page might have been truncated.
236  *                      The caller should back up to acquiring a new page and
237  *                      trying again.  The aop will be taking reasonable
238  *                      precautions not to livelock.  If the caller held a page
239  *                      reference, it should drop it before retrying.  Returned
240  *                      by readpage().
241  *
242  * address_space_operation functions return these large constants to indicate
243  * special semantics to the caller.  These are much larger than the bytes in a
244  * page to allow for functions that return the number of bytes operated on in a
245  * given page.
246  */
247 
248 enum positive_aop_returns {
249         AOP_WRITEPAGE_ACTIVATE  = 0x80000,
250         AOP_TRUNCATED_PAGE      = 0x80001,
251 };
252 
253 #define AOP_FLAG_UNINTERRUPTIBLE        0x0001 /* will not do a short write */
254 #define AOP_FLAG_CONT_EXPAND            0x0002 /* called from cont_expand */
255 #define AOP_FLAG_NOFS                   0x0004 /* used by filesystem to direct
256                                                 * helper code (eg buffer layer)
257                                                 * to clear GFP_FS from alloc */
258 
259 /*
260  * oh the beauties of C type declarations.
261  */
262 struct page;
263 struct address_space;
264 struct writeback_control;
265 
266 #define IOCB_EVENTFD            (1 << 0)
267 #define IOCB_APPEND             (1 << 1)
268 #define IOCB_DIRECT             (1 << 2)
269 #define IOCB_HIPRI              (1 << 3)
270 #define IOCB_DSYNC              (1 << 4)
271 #define IOCB_SYNC               (1 << 5)
272 #define IOCB_WRITE              (1 << 6)
273 
274 struct kiocb {
275         struct file             *ki_filp;
276         loff_t                  ki_pos;
277         void (*ki_complete)(struct kiocb *iocb, long ret, long ret2);
278         void                    *private;
279         int                     ki_flags;
280 };
281 
282 static inline bool is_sync_kiocb(struct kiocb *kiocb)
283 {
284         return kiocb->ki_complete == NULL;
285 }
286 
287 static inline int iocb_flags(struct file *file);
288 
289 static inline void init_sync_kiocb(struct kiocb *kiocb, struct file *filp)
290 {
291         *kiocb = (struct kiocb) {
292                 .ki_filp = filp,
293                 .ki_flags = iocb_flags(filp),
294         };
295 }
296 
297 /*
298  * "descriptor" for what we're up to with a read.
299  * This allows us to use the same read code yet
300  * have multiple different users of the data that
301  * we read from a file.
302  *
303  * The simplest case just copies the data to user
304  * mode.
305  */
306 typedef struct {
307         size_t written;
308         size_t count;
309         union {
310                 char __user *buf;
311                 void *data;
312         } arg;
313         int error;
314 } read_descriptor_t;
315 
316 typedef int (*read_actor_t)(read_descriptor_t *, struct page *,
317                 unsigned long, unsigned long);
318 
319 struct address_space_operations {
320         int (*writepage)(struct page *page, struct writeback_control *wbc);
321         int (*readpage)(struct file *, struct page *);
322 
323         /* Write back some dirty pages from this mapping. */
324         int (*writepages)(struct address_space *, struct writeback_control *);
325 
326         /* Set a page dirty.  Return true if this dirtied it */
327         int (*set_page_dirty)(struct page *page);
328 
329         int (*readpages)(struct file *filp, struct address_space *mapping,
330                         struct list_head *pages, unsigned nr_pages);
331 
332         int (*write_begin)(struct file *, struct address_space *mapping,
333                                 loff_t pos, unsigned len, unsigned flags,
334                                 struct page **pagep, void **fsdata);
335         int (*write_end)(struct file *, struct address_space *mapping,
336                                 loff_t pos, unsigned len, unsigned copied,
337                                 struct page *page, void *fsdata);
338 
339         /* Unfortunately this kludge is needed for FIBMAP. Don't use it */
340         sector_t (*bmap)(struct address_space *, sector_t);
341         void (*invalidatepage) (struct page *, unsigned int, unsigned int);
342         int (*releasepage) (struct page *, gfp_t);
343         void (*freepage)(struct page *);
344         ssize_t (*direct_IO)(struct kiocb *, struct iov_iter *iter);
345         /*
346          * migrate the contents of a page to the specified target. If
347          * migrate_mode is MIGRATE_ASYNC, it must not block.
348          */
349         int (*migratepage) (struct address_space *,
350                         struct page *, struct page *, enum migrate_mode);
351         bool (*isolate_page)(struct page *, isolate_mode_t);
352         void (*putback_page)(struct page *);
353         int (*launder_page) (struct page *);
354         int (*is_partially_uptodate) (struct page *, unsigned long,
355                                         unsigned long);
356         void (*is_dirty_writeback) (struct page *, bool *, bool *);
357         int (*error_remove_page)(struct address_space *, struct page *);
358 
359         /* swapfile support */
360         int (*swap_activate)(struct swap_info_struct *sis, struct file *file,
361                                 sector_t *span);
362         void (*swap_deactivate)(struct file *file);
363 };
364 
365 extern const struct address_space_operations empty_aops;
366 
367 /*
368  * pagecache_write_begin/pagecache_write_end must be used by general code
369  * to write into the pagecache.
370  */
371 int pagecache_write_begin(struct file *, struct address_space *mapping,
372                                 loff_t pos, unsigned len, unsigned flags,
373                                 struct page **pagep, void **fsdata);
374 
375 int pagecache_write_end(struct file *, struct address_space *mapping,
376                                 loff_t pos, unsigned len, unsigned copied,
377                                 struct page *page, void *fsdata);
378 
379 struct address_space {
380         struct inode            *host;          /* owner: inode, block_device */
381         struct radix_tree_root  page_tree;      /* radix tree of all pages */
382         spinlock_t              tree_lock;      /* and lock protecting it */
383         atomic_t                i_mmap_writable;/* count VM_SHARED mappings */
384         struct rb_root          i_mmap;         /* tree of private and shared mappings */
385         struct rw_semaphore     i_mmap_rwsem;   /* protect tree, count, list */
386         /* Protected by tree_lock together with the radix tree */
387         unsigned long           nrpages;        /* number of total pages */
388         /* number of shadow or DAX exceptional entries */
389         unsigned long           nrexceptional;
390         pgoff_t                 writeback_index;/* writeback starts here */
391         const struct address_space_operations *a_ops;   /* methods */
392         unsigned long           flags;          /* error bits */
393         spinlock_t              private_lock;   /* for use by the address_space */
394         gfp_t                   gfp_mask;       /* implicit gfp mask for allocations */
395         struct list_head        private_list;   /* ditto */
396         void                    *private_data;  /* ditto */
397 } __attribute__((aligned(sizeof(long))));
398         /*
399          * On most architectures that alignment is already the case; but
400          * must be enforced here for CRIS, to let the least significant bit
401          * of struct page's "mapping" pointer be used for PAGE_MAPPING_ANON.
402          */
403 struct request_queue;
404 
405 struct block_device {
406         dev_t                   bd_dev;  /* not a kdev_t - it's a search key */
407         int                     bd_openers;
408         struct inode *          bd_inode;       /* will die */
409         struct super_block *    bd_super;
410         struct mutex            bd_mutex;       /* open/close mutex */
411         void *                  bd_claiming;
412         void *                  bd_holder;
413         int                     bd_holders;
414         bool                    bd_write_holder;
415 #ifdef CONFIG_SYSFS
416         struct list_head        bd_holder_disks;
417 #endif
418         struct block_device *   bd_contains;
419         unsigned                bd_block_size;
420         struct hd_struct *      bd_part;
421         /* number of times partitions within this device have been opened. */
422         unsigned                bd_part_count;
423         int                     bd_invalidated;
424         struct gendisk *        bd_disk;
425         struct request_queue *  bd_queue;
426         struct list_head        bd_list;
427         /*
428          * Private data.  You must have bd_claim'ed the block_device
429          * to use this.  NOTE:  bd_claim allows an owner to claim
430          * the same device multiple times, the owner must take special
431          * care to not mess up bd_private for that case.
432          */
433         unsigned long           bd_private;
434 
435         /* The counter of freeze processes */
436         int                     bd_fsfreeze_count;
437         /* Mutex for freeze */
438         struct mutex            bd_fsfreeze_mutex;
439 };
440 
441 /*
442  * Radix-tree tags, for tagging dirty and writeback pages within the pagecache
443  * radix trees
444  */
445 #define PAGECACHE_TAG_DIRTY     0
446 #define PAGECACHE_TAG_WRITEBACK 1
447 #define PAGECACHE_TAG_TOWRITE   2
448 
449 int mapping_tagged(struct address_space *mapping, int tag);
450 
451 static inline void i_mmap_lock_write(struct address_space *mapping)
452 {
453         down_write(&mapping->i_mmap_rwsem);
454 }
455 
456 static inline void i_mmap_unlock_write(struct address_space *mapping)
457 {
458         up_write(&mapping->i_mmap_rwsem);
459 }
460 
461 static inline void i_mmap_lock_read(struct address_space *mapping)
462 {
463         down_read(&mapping->i_mmap_rwsem);
464 }
465 
466 static inline void i_mmap_unlock_read(struct address_space *mapping)
467 {
468         up_read(&mapping->i_mmap_rwsem);
469 }
470 
471 /*
472  * Might pages of this file be mapped into userspace?
473  */
474 static inline int mapping_mapped(struct address_space *mapping)
475 {
476         return  !RB_EMPTY_ROOT(&mapping->i_mmap);
477 }
478 
479 /*
480  * Might pages of this file have been modified in userspace?
481  * Note that i_mmap_writable counts all VM_SHARED vmas: do_mmap_pgoff
482  * marks vma as VM_SHARED if it is shared, and the file was opened for
483  * writing i.e. vma may be mprotected writable even if now readonly.
484  *
485  * If i_mmap_writable is negative, no new writable mappings are allowed. You
486  * can only deny writable mappings, if none exists right now.
487  */
488 static inline int mapping_writably_mapped(struct address_space *mapping)
489 {
490         return atomic_read(&mapping->i_mmap_writable) > 0;
491 }
492 
493 static inline int mapping_map_writable(struct address_space *mapping)
494 {
495         return atomic_inc_unless_negative(&mapping->i_mmap_writable) ?
496                 0 : -EPERM;
497 }
498 
499 static inline void mapping_unmap_writable(struct address_space *mapping)
500 {
501         atomic_dec(&mapping->i_mmap_writable);
502 }
503 
504 static inline int mapping_deny_writable(struct address_space *mapping)
505 {
506         return atomic_dec_unless_positive(&mapping->i_mmap_writable) ?
507                 0 : -EBUSY;
508 }
509 
510 static inline void mapping_allow_writable(struct address_space *mapping)
511 {
512         atomic_inc(&mapping->i_mmap_writable);
513 }
514 
515 /*
516  * Use sequence counter to get consistent i_size on 32-bit processors.
517  */
518 #if BITS_PER_LONG==32 && defined(CONFIG_SMP)
519 #include <linux/seqlock.h>
520 #define __NEED_I_SIZE_ORDERED
521 #define i_size_ordered_init(inode) seqcount_init(&inode->i_size_seqcount)
522 #else
523 #define i_size_ordered_init(inode) do { } while (0)
524 #endif
525 
526 struct posix_acl;
527 #define ACL_NOT_CACHED ((void *)(-1))
528 #define ACL_DONT_CACHE ((void *)(-3))
529 
530 static inline struct posix_acl *
531 uncached_acl_sentinel(struct task_struct *task)
532 {
533         return (void *)task + 1;
534 }
535 
536 static inline bool
537 is_uncached_acl(struct posix_acl *acl)
538 {
539         return (long)acl & 1;
540 }
541 
542 #define IOP_FASTPERM    0x0001
543 #define IOP_LOOKUP      0x0002
544 #define IOP_NOFOLLOW    0x0004
545 #define IOP_XATTR       0x0008
546 #define IOP_DEFAULT_READLINK    0x0010
547 
548 /*
549  * Keep mostly read-only and often accessed (especially for
550  * the RCU path lookup and 'stat' data) fields at the beginning
551  * of the 'struct inode'
552  */
553 struct inode {
554         umode_t                 i_mode;
555         unsigned short          i_opflags;
556         kuid_t                  i_uid;
557         kgid_t                  i_gid;
558         unsigned int            i_flags;
559 
560 #ifdef CONFIG_FS_POSIX_ACL
561         struct posix_acl        *i_acl;
562         struct posix_acl        *i_default_acl;
563 #endif
564 
565         const struct inode_operations   *i_op;
566         struct super_block      *i_sb;
567         struct address_space    *i_mapping;
568 
569 #ifdef CONFIG_SECURITY
570         void                    *i_security;
571 #endif
572 
573         /* Stat data, not accessed from path walking */
574         unsigned long           i_ino;
575         /*
576          * Filesystems may only read i_nlink directly.  They shall use the
577          * following functions for modification:
578          *
579          *    (set|clear|inc|drop)_nlink
580          *    inode_(inc|dec)_link_count
581          */
582         union {
583                 const unsigned int i_nlink;
584                 unsigned int __i_nlink;
585         };
586         dev_t                   i_rdev;
587         loff_t                  i_size;
588         struct timespec         i_atime;
589         struct timespec         i_mtime;
590         struct timespec         i_ctime;
591         spinlock_t              i_lock; /* i_blocks, i_bytes, maybe i_size */
592         unsigned short          i_bytes;
593         unsigned int            i_blkbits;
594         blkcnt_t                i_blocks;
595 
596 #ifdef __NEED_I_SIZE_ORDERED
597         seqcount_t              i_size_seqcount;
598 #endif
599 
600         /* Misc */
601         unsigned long           i_state;
602         struct rw_semaphore     i_rwsem;
603 
604         unsigned long           dirtied_when;   /* jiffies of first dirtying */
605         unsigned long           dirtied_time_when;
606 
607         struct hlist_node       i_hash;
608         struct list_head        i_io_list;      /* backing dev IO list */
609 #ifdef CONFIG_CGROUP_WRITEBACK
610         struct bdi_writeback    *i_wb;          /* the associated cgroup wb */
611 
612         /* foreign inode detection, see wbc_detach_inode() */
613         int                     i_wb_frn_winner;
614         u16                     i_wb_frn_avg_time;
615         u16                     i_wb_frn_history;
616 #endif
617         struct list_head        i_lru;          /* inode LRU list */
618         struct list_head        i_sb_list;
619         struct list_head        i_wb_list;      /* backing dev writeback list */
620         union {
621                 struct hlist_head       i_dentry;
622                 struct rcu_head         i_rcu;
623         };
624         u64                     i_version;
625         atomic_t                i_count;
626         atomic_t                i_dio_count;
627         atomic_t                i_writecount;
628 #ifdef CONFIG_IMA
629         atomic_t                i_readcount; /* struct files open RO */
630 #endif
631         const struct file_operations    *i_fop; /* former ->i_op->default_file_ops */
632         struct file_lock_context        *i_flctx;
633         struct address_space    i_data;
634         struct list_head        i_devices;
635         union {
636                 struct pipe_inode_info  *i_pipe;
637                 struct block_device     *i_bdev;
638                 struct cdev             *i_cdev;
639                 char                    *i_link;
640                 unsigned                i_dir_seq;
641         };
642 
643         __u32                   i_generation;
644 
645 #ifdef CONFIG_FSNOTIFY
646         __u32                   i_fsnotify_mask; /* all events this inode cares about */
647         struct hlist_head       i_fsnotify_marks;
648 #endif
649 
650 #if IS_ENABLED(CONFIG_FS_ENCRYPTION)
651         struct fscrypt_info     *i_crypt_info;
652 #endif
653 
654         void                    *i_private; /* fs or device private pointer */
655 };
656 
657 static inline int inode_unhashed(struct inode *inode)
658 {
659         return hlist_unhashed(&inode->i_hash);
660 }
661 
662 /*
663  * inode->i_mutex nesting subclasses for the lock validator:
664  *
665  * 0: the object of the current VFS operation
666  * 1: parent
667  * 2: child/target
668  * 3: xattr
669  * 4: second non-directory
670  * 5: second parent (when locking independent directories in rename)
671  *
672  * I_MUTEX_NONDIR2 is for certain operations (such as rename) which lock two
673  * non-directories at once.
674  *
675  * The locking order between these classes is
676  * parent[2] -> child -> grandchild -> normal -> xattr -> second non-directory
677  */
678 enum inode_i_mutex_lock_class
679 {
680         I_MUTEX_NORMAL,
681         I_MUTEX_PARENT,
682         I_MUTEX_CHILD,
683         I_MUTEX_XATTR,
684         I_MUTEX_NONDIR2,
685         I_MUTEX_PARENT2,
686 };
687 
688 static inline void inode_lock(struct inode *inode)
689 {
690         down_write(&inode->i_rwsem);
691 }
692 
693 static inline void inode_unlock(struct inode *inode)
694 {
695         up_write(&inode->i_rwsem);
696 }
697 
698 static inline void inode_lock_shared(struct inode *inode)
699 {
700         down_read(&inode->i_rwsem);
701 }
702 
703 static inline void inode_unlock_shared(struct inode *inode)
704 {
705         up_read(&inode->i_rwsem);
706 }
707 
708 static inline int inode_trylock(struct inode *inode)
709 {
710         return down_write_trylock(&inode->i_rwsem);
711 }
712 
713 static inline int inode_trylock_shared(struct inode *inode)
714 {
715         return down_read_trylock(&inode->i_rwsem);
716 }
717 
718 static inline int inode_is_locked(struct inode *inode)
719 {
720         return rwsem_is_locked(&inode->i_rwsem);
721 }
722 
723 static inline void inode_lock_nested(struct inode *inode, unsigned subclass)
724 {
725         down_write_nested(&inode->i_rwsem, subclass);
726 }
727 
728 void lock_two_nondirectories(struct inode *, struct inode*);
729 void unlock_two_nondirectories(struct inode *, struct inode*);
730 
731 /*
732  * NOTE: in a 32bit arch with a preemptable kernel and
733  * an UP compile the i_size_read/write must be atomic
734  * with respect to the local cpu (unlike with preempt disabled),
735  * but they don't need to be atomic with respect to other cpus like in
736  * true SMP (so they need either to either locally disable irq around
737  * the read or for example on x86 they can be still implemented as a
738  * cmpxchg8b without the need of the lock prefix). For SMP compiles
739  * and 64bit archs it makes no difference if preempt is enabled or not.
740  */
741 static inline loff_t i_size_read(const struct inode *inode)
742 {
743 #if BITS_PER_LONG==32 && defined(CONFIG_SMP)
744         loff_t i_size;
745         unsigned int seq;
746 
747         do {
748                 seq = read_seqcount_begin(&inode->i_size_seqcount);
749                 i_size = inode->i_size;
750         } while (read_seqcount_retry(&inode->i_size_seqcount, seq));
751         return i_size;
752 #elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPT)
753         loff_t i_size;
754 
755         preempt_disable();
756         i_size = inode->i_size;
757         preempt_enable();
758         return i_size;
759 #else
760         return inode->i_size;
761 #endif
762 }
763 
764 /*
765  * NOTE: unlike i_size_read(), i_size_write() does need locking around it
766  * (normally i_mutex), otherwise on 32bit/SMP an update of i_size_seqcount
767  * can be lost, resulting in subsequent i_size_read() calls spinning forever.
768  */
769 static inline void i_size_write(struct inode *inode, loff_t i_size)
770 {
771 #if BITS_PER_LONG==32 && defined(CONFIG_SMP)
772         preempt_disable();
773         write_seqcount_begin(&inode->i_size_seqcount);
774         inode->i_size = i_size;
775         write_seqcount_end(&inode->i_size_seqcount);
776         preempt_enable();
777 #elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPT)
778         preempt_disable();
779         inode->i_size = i_size;
780         preempt_enable();
781 #else
782         inode->i_size = i_size;
783 #endif
784 }
785 
786 static inline unsigned iminor(const struct inode *inode)
787 {
788         return MINOR(inode->i_rdev);
789 }
790 
791 static inline unsigned imajor(const struct inode *inode)
792 {
793         return MAJOR(inode->i_rdev);
794 }
795 
796 extern struct block_device *I_BDEV(struct inode *inode);
797 
798 struct fown_struct {
799         rwlock_t lock;          /* protects pid, uid, euid fields */
800         struct pid *pid;        /* pid or -pgrp where SIGIO should be sent */
801         enum pid_type pid_type; /* Kind of process group SIGIO should be sent to */
802         kuid_t uid, euid;       /* uid/euid of process setting the owner */
803         int signum;             /* posix.1b rt signal to be delivered on IO */
804 };
805 
806 /*
807  * Track a single file's readahead state
808  */
809 struct file_ra_state {
810         pgoff_t start;                  /* where readahead started */
811         unsigned int size;              /* # of readahead pages */
812         unsigned int async_size;        /* do asynchronous readahead when
813                                            there are only # of pages ahead */
814 
815         unsigned int ra_pages;          /* Maximum readahead window */
816         unsigned int mmap_miss;         /* Cache miss stat for mmap accesses */
817         loff_t prev_pos;                /* Cache last read() position */
818 };
819 
820 /*
821  * Check if @index falls in the readahead windows.
822  */
823 static inline int ra_has_index(struct file_ra_state *ra, pgoff_t index)
824 {
825         return (index >= ra->start &&
826                 index <  ra->start + ra->size);
827 }
828 
829 struct file {
830         union {
831                 struct llist_node       fu_llist;
832                 struct rcu_head         fu_rcuhead;
833         } f_u;
834         struct path             f_path;
835         struct inode            *f_inode;       /* cached value */
836         const struct file_operations    *f_op;
837 
838         /*
839          * Protects f_ep_links, f_flags.
840          * Must not be taken from IRQ context.
841          */
842         spinlock_t              f_lock;
843         atomic_long_t           f_count;
844         unsigned int            f_flags;
845         fmode_t                 f_mode;
846         struct mutex            f_pos_lock;
847         loff_t                  f_pos;
848         struct fown_struct      f_owner;
849         const struct cred       *f_cred;
850         struct file_ra_state    f_ra;
851 
852         u64                     f_version;
853 #ifdef CONFIG_SECURITY
854         void                    *f_security;
855 #endif
856         /* needed for tty driver, and maybe others */
857         void                    *private_data;
858 
859 #ifdef CONFIG_EPOLL
860         /* Used by fs/eventpoll.c to link all the hooks to this file */
861         struct list_head        f_ep_links;
862         struct list_head        f_tfile_llink;
863 #endif /* #ifdef CONFIG_EPOLL */
864         struct address_space    *f_mapping;
865 } __attribute__((aligned(4)));  /* lest something weird decides that 2 is OK */
866 
867 struct file_handle {
868         __u32 handle_bytes;
869         int handle_type;
870         /* file identifier */
871         unsigned char f_handle[0];
872 };
873 
874 static inline struct file *get_file(struct file *f)
875 {
876         atomic_long_inc(&f->f_count);
877         return f;
878 }
879 #define get_file_rcu(x) atomic_long_inc_not_zero(&(x)->f_count)
880 #define fput_atomic(x)  atomic_long_add_unless(&(x)->f_count, -1, 1)
881 #define file_count(x)   atomic_long_read(&(x)->f_count)
882 
883 #define MAX_NON_LFS     ((1UL<<31) - 1)
884 
885 /* Page cache limit. The filesystems should put that into their s_maxbytes 
886    limits, otherwise bad things can happen in VM. */ 
887 #if BITS_PER_LONG==32
888 #define MAX_LFS_FILESIZE        (((loff_t)PAGE_SIZE << (BITS_PER_LONG-1))-1)
889 #elif BITS_PER_LONG==64
890 #define MAX_LFS_FILESIZE        ((loff_t)0x7fffffffffffffffLL)
891 #endif
892 
893 #define FL_POSIX        1
894 #define FL_FLOCK        2
895 #define FL_DELEG        4       /* NFSv4 delegation */
896 #define FL_ACCESS       8       /* not trying to lock, just looking */
897 #define FL_EXISTS       16      /* when unlocking, test for existence */
898 #define FL_LEASE        32      /* lease held on this file */
899 #define FL_CLOSE        64      /* unlock on close */
900 #define FL_SLEEP        128     /* A blocking lock */
901 #define FL_DOWNGRADE_PENDING    256 /* Lease is being downgraded */
902 #define FL_UNLOCK_PENDING       512 /* Lease is being broken */
903 #define FL_OFDLCK       1024    /* lock is "owned" by struct file */
904 #define FL_LAYOUT       2048    /* outstanding pNFS layout */
905 
906 /*
907  * Special return value from posix_lock_file() and vfs_lock_file() for
908  * asynchronous locking.
909  */
910 #define FILE_LOCK_DEFERRED 1
911 
912 /* legacy typedef, should eventually be removed */
913 typedef void *fl_owner_t;
914 
915 struct file_lock;
916 
917 struct file_lock_operations {
918         void (*fl_copy_lock)(struct file_lock *, struct file_lock *);
919         void (*fl_release_private)(struct file_lock *);
920 };
921 
922 struct lock_manager_operations {
923         int (*lm_compare_owner)(struct file_lock *, struct file_lock *);
924         unsigned long (*lm_owner_key)(struct file_lock *);
925         fl_owner_t (*lm_get_owner)(fl_owner_t);
926         void (*lm_put_owner)(fl_owner_t);
927         void (*lm_notify)(struct file_lock *);  /* unblock callback */
928         int (*lm_grant)(struct file_lock *, int);
929         bool (*lm_break)(struct file_lock *);
930         int (*lm_change)(struct file_lock *, int, struct list_head *);
931         void (*lm_setup)(struct file_lock *, void **);
932 };
933 
934 struct lock_manager {
935         struct list_head list;
936         /*
937          * NFSv4 and up also want opens blocked during the grace period;
938          * NLM doesn't care:
939          */
940         bool block_opens;
941 };
942 
943 struct net;
944 void locks_start_grace(struct net *, struct lock_manager *);
945 void locks_end_grace(struct lock_manager *);
946 int locks_in_grace(struct net *);
947 int opens_in_grace(struct net *);
948 
949 /* that will die - we need it for nfs_lock_info */
950 #include <linux/nfs_fs_i.h>
951 
952 /*
953  * struct file_lock represents a generic "file lock". It's used to represent
954  * POSIX byte range locks, BSD (flock) locks, and leases. It's important to
955  * note that the same struct is used to represent both a request for a lock and
956  * the lock itself, but the same object is never used for both.
957  *
958  * FIXME: should we create a separate "struct lock_request" to help distinguish
959  * these two uses?
960  *
961  * The varous i_flctx lists are ordered by:
962  *
963  * 1) lock owner
964  * 2) lock range start
965  * 3) lock range end
966  *
967  * Obviously, the last two criteria only matter for POSIX locks.
968  */
969 struct file_lock {
970         struct file_lock *fl_next;      /* singly linked list for this inode  */
971         struct list_head fl_list;       /* link into file_lock_context */
972         struct hlist_node fl_link;      /* node in global lists */
973         struct list_head fl_block;      /* circular list of blocked processes */
974         fl_owner_t fl_owner;
975         unsigned int fl_flags;
976         unsigned char fl_type;
977         unsigned int fl_pid;
978         int fl_link_cpu;                /* what cpu's list is this on? */
979         struct pid *fl_nspid;
980         wait_queue_head_t fl_wait;
981         struct file *fl_file;
982         loff_t fl_start;
983         loff_t fl_end;
984 
985         struct fasync_struct *  fl_fasync; /* for lease break notifications */
986         /* for lease breaks: */
987         unsigned long fl_break_time;
988         unsigned long fl_downgrade_time;
989 
990         const struct file_lock_operations *fl_ops;      /* Callbacks for filesystems */
991         const struct lock_manager_operations *fl_lmops; /* Callbacks for lockmanagers */
992         union {
993                 struct nfs_lock_info    nfs_fl;
994                 struct nfs4_lock_info   nfs4_fl;
995                 struct {
996                         struct list_head link;  /* link in AFS vnode's pending_locks list */
997                         int state;              /* state of grant or error if -ve */
998                 } afs;
999         } fl_u;
1000 };
1001 
1002 struct file_lock_context {
1003         spinlock_t              flc_lock;
1004         struct list_head        flc_flock;
1005         struct list_head        flc_posix;
1006         struct list_head        flc_lease;
1007 };
1008 
1009 /* The following constant reflects the upper bound of the file/locking space */
1010 #ifndef OFFSET_MAX
1011 #define INT_LIMIT(x)    (~((x)1 << (sizeof(x)*8 - 1)))
1012 #define OFFSET_MAX      INT_LIMIT(loff_t)
1013 #define OFFT_OFFSET_MAX INT_LIMIT(off_t)
1014 #endif
1015 
1016 #include <linux/fcntl.h>
1017 
1018 extern void send_sigio(struct fown_struct *fown, int fd, int band);
1019 
1020 /*
1021  * Return the inode to use for locking
1022  *
1023  * For overlayfs this should be the overlay inode, not the real inode returned
1024  * by file_inode().  For any other fs file_inode(filp) and locks_inode(filp) are
1025  * equal.
1026  */
1027 static inline struct inode *locks_inode(const struct file *f)
1028 {
1029         return f->f_path.dentry->d_inode;
1030 }
1031 
1032 #ifdef CONFIG_FILE_LOCKING
1033 extern int fcntl_getlk(struct file *, unsigned int, struct flock __user *);
1034 extern int fcntl_setlk(unsigned int, struct file *, unsigned int,
1035                         struct flock __user *);
1036 
1037 #if BITS_PER_LONG == 32
1038 extern int fcntl_getlk64(struct file *, unsigned int, struct flock64 __user *);
1039 extern int fcntl_setlk64(unsigned int, struct file *, unsigned int,
1040                         struct flock64 __user *);
1041 #endif
1042 
1043 extern int fcntl_setlease(unsigned int fd, struct file *filp, long arg);
1044 extern int fcntl_getlease(struct file *filp);
1045 
1046 /* fs/locks.c */
1047 void locks_free_lock_context(struct inode *inode);
1048 void locks_free_lock(struct file_lock *fl);
1049 extern void locks_init_lock(struct file_lock *);
1050 extern struct file_lock * locks_alloc_lock(void);
1051 extern void locks_copy_lock(struct file_lock *, struct file_lock *);
1052 extern void locks_copy_conflock(struct file_lock *, struct file_lock *);
1053 extern void locks_remove_posix(struct file *, fl_owner_t);
1054 extern void locks_remove_file(struct file *);
1055 extern void locks_release_private(struct file_lock *);
1056 extern void posix_test_lock(struct file *, struct file_lock *);
1057 extern int posix_lock_file(struct file *, struct file_lock *, struct file_lock *);
1058 extern int posix_unblock_lock(struct file_lock *);
1059 extern int vfs_test_lock(struct file *, struct file_lock *);
1060 extern int vfs_lock_file(struct file *, unsigned int, struct file_lock *, struct file_lock *);
1061 extern int vfs_cancel_lock(struct file *filp, struct file_lock *fl);
1062 extern int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl);
1063 extern int __break_lease(struct inode *inode, unsigned int flags, unsigned int type);
1064 extern void lease_get_mtime(struct inode *, struct timespec *time);
1065 extern int generic_setlease(struct file *, long, struct file_lock **, void **priv);
1066 extern int vfs_setlease(struct file *, long, struct file_lock **, void **);
1067 extern int lease_modify(struct file_lock *, int, struct list_head *);
1068 struct files_struct;
1069 extern void show_fd_locks(struct seq_file *f,
1070                          struct file *filp, struct files_struct *files);
1071 #else /* !CONFIG_FILE_LOCKING */
1072 static inline int fcntl_getlk(struct file *file, unsigned int cmd,
1073                               struct flock __user *user)
1074 {
1075         return -EINVAL;
1076 }
1077 
1078 static inline int fcntl_setlk(unsigned int fd, struct file *file,
1079                               unsigned int cmd, struct flock __user *user)
1080 {
1081         return -EACCES;
1082 }
1083 
1084 #if BITS_PER_LONG == 32
1085 static inline int fcntl_getlk64(struct file *file, unsigned int cmd,
1086                                 struct flock64 __user *user)
1087 {
1088         return -EINVAL;
1089 }
1090 
1091 static inline int fcntl_setlk64(unsigned int fd, struct file *file,
1092                                 unsigned int cmd, struct flock64 __user *user)
1093 {
1094         return -EACCES;
1095 }
1096 #endif
1097 static inline int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
1098 {
1099         return -EINVAL;
1100 }
1101 
1102 static inline int fcntl_getlease(struct file *filp)
1103 {
1104         return F_UNLCK;
1105 }
1106 
1107 static inline void
1108 locks_free_lock_context(struct inode *inode)
1109 {
1110 }
1111 
1112 static inline void locks_init_lock(struct file_lock *fl)
1113 {
1114         return;
1115 }
1116 
1117 static inline void locks_copy_conflock(struct file_lock *new, struct file_lock *fl)
1118 {
1119         return;
1120 }
1121 
1122 static inline void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
1123 {
1124         return;
1125 }
1126 
1127 static inline void locks_remove_posix(struct file *filp, fl_owner_t owner)
1128 {
1129         return;
1130 }
1131 
1132 static inline void locks_remove_file(struct file *filp)
1133 {
1134         return;
1135 }
1136 
1137 static inline void posix_test_lock(struct file *filp, struct file_lock *fl)
1138 {
1139         return;
1140 }
1141 
1142 static inline int posix_lock_file(struct file *filp, struct file_lock *fl,
1143                                   struct file_lock *conflock)
1144 {
1145         return -ENOLCK;
1146 }
1147 
1148 static inline int posix_unblock_lock(struct file_lock *waiter)
1149 {
1150         return -ENOENT;
1151 }
1152 
1153 static inline int vfs_test_lock(struct file *filp, struct file_lock *fl)
1154 {
1155         return 0;
1156 }
1157 
1158 static inline int vfs_lock_file(struct file *filp, unsigned int cmd,
1159                                 struct file_lock *fl, struct file_lock *conf)
1160 {
1161         return -ENOLCK;
1162 }
1163 
1164 static inline int vfs_cancel_lock(struct file *filp, struct file_lock *fl)
1165 {
1166         return 0;
1167 }
1168 
1169 static inline int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl)
1170 {
1171         return -ENOLCK;
1172 }
1173 
1174 static inline int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
1175 {
1176         return 0;
1177 }
1178 
1179 static inline void lease_get_mtime(struct inode *inode, struct timespec *time)
1180 {
1181         return;
1182 }
1183 
1184 static inline int generic_setlease(struct file *filp, long arg,
1185                                     struct file_lock **flp, void **priv)
1186 {
1187         return -EINVAL;
1188 }
1189 
1190 static inline int vfs_setlease(struct file *filp, long arg,
1191                                struct file_lock **lease, void **priv)
1192 {
1193         return -EINVAL;
1194 }
1195 
1196 static inline int lease_modify(struct file_lock *fl, int arg,
1197                                struct list_head *dispose)
1198 {
1199         return -EINVAL;
1200 }
1201 
1202 struct files_struct;
1203 static inline void show_fd_locks(struct seq_file *f,
1204                         struct file *filp, struct files_struct *files) {}
1205 #endif /* !CONFIG_FILE_LOCKING */
1206 
1207 static inline struct inode *file_inode(const struct file *f)
1208 {
1209         return f->f_inode;
1210 }
1211 
1212 static inline struct dentry *file_dentry(const struct file *file)
1213 {
1214         return d_real(file->f_path.dentry, file_inode(file), 0);
1215 }
1216 
1217 static inline int locks_lock_file_wait(struct file *filp, struct file_lock *fl)
1218 {
1219         return locks_lock_inode_wait(locks_inode(filp), fl);
1220 }
1221 
1222 struct fasync_struct {
1223         spinlock_t              fa_lock;
1224         int                     magic;
1225         int                     fa_fd;
1226         struct fasync_struct    *fa_next; /* singly linked list */
1227         struct file             *fa_file;
1228         struct rcu_head         fa_rcu;
1229 };
1230 
1231 #define FASYNC_MAGIC 0x4601
1232 
1233 /* SMP safe fasync helpers: */
1234 extern int fasync_helper(int, struct file *, int, struct fasync_struct **);
1235 extern struct fasync_struct *fasync_insert_entry(int, struct file *, struct fasync_struct **, struct fasync_struct *);
1236 extern int fasync_remove_entry(struct file *, struct fasync_struct **);
1237 extern struct fasync_struct *fasync_alloc(void);
1238 extern void fasync_free(struct fasync_struct *);
1239 
1240 /* can be called from interrupts */
1241 extern void kill_fasync(struct fasync_struct **, int, int);
1242 
1243 extern void __f_setown(struct file *filp, struct pid *, enum pid_type, int force);
1244 extern void f_setown(struct file *filp, unsigned long arg, int force);
1245 extern void f_delown(struct file *filp);
1246 extern pid_t f_getown(struct file *filp);
1247 extern int send_sigurg(struct fown_struct *fown);
1248 
1249 struct mm_struct;
1250 
1251 /*
1252  *      Umount options
1253  */
1254 
1255 #define MNT_FORCE       0x00000001      /* Attempt to forcibily umount */
1256 #define MNT_DETACH      0x00000002      /* Just detach from the tree */
1257 #define MNT_EXPIRE      0x00000004      /* Mark for expiry */
1258 #define UMOUNT_NOFOLLOW 0x00000008      /* Don't follow symlink on umount */
1259 #define UMOUNT_UNUSED   0x80000000      /* Flag guaranteed to be unused */
1260 
1261 /* sb->s_iflags */
1262 #define SB_I_CGROUPWB   0x00000001      /* cgroup-aware writeback enabled */
1263 #define SB_I_NOEXEC     0x00000002      /* Ignore executables on this fs */
1264 #define SB_I_NODEV      0x00000004      /* Ignore devices on this fs */
1265 
1266 /* sb->s_iflags to limit user namespace mounts */
1267 #define SB_I_USERNS_VISIBLE             0x00000010 /* fstype already mounted */
1268 
1269 /* Possible states of 'frozen' field */
1270 enum {
1271         SB_UNFROZEN = 0,                /* FS is unfrozen */
1272         SB_FREEZE_WRITE = 1,            /* Writes, dir ops, ioctls frozen */
1273         SB_FREEZE_PAGEFAULT = 2,        /* Page faults stopped as well */
1274         SB_FREEZE_FS = 3,               /* For internal FS use (e.g. to stop
1275                                          * internal threads if needed) */
1276         SB_FREEZE_COMPLETE = 4,         /* ->freeze_fs finished successfully */
1277 };
1278 
1279 #define SB_FREEZE_LEVELS (SB_FREEZE_COMPLETE - 1)
1280 
1281 struct sb_writers {
1282         int                             frozen;         /* Is sb frozen? */
1283         wait_queue_head_t               wait_unfrozen;  /* for get_super_thawed() */
1284         struct percpu_rw_semaphore      rw_sem[SB_FREEZE_LEVELS];
1285 };
1286 
1287 struct super_block {
1288         struct list_head        s_list;         /* Keep this first */
1289         dev_t                   s_dev;          /* search index; _not_ kdev_t */
1290         unsigned char           s_blocksize_bits;
1291         unsigned long           s_blocksize;
1292         loff_t                  s_maxbytes;     /* Max file size */
1293         struct file_system_type *s_type;
1294         const struct super_operations   *s_op;
1295         const struct dquot_operations   *dq_op;
1296         const struct quotactl_ops       *s_qcop;
1297         const struct export_operations *s_export_op;
1298         unsigned long           s_flags;
1299         unsigned long           s_iflags;       /* internal SB_I_* flags */
1300         unsigned long           s_magic;
1301         struct dentry           *s_root;
1302         struct rw_semaphore     s_umount;
1303         int                     s_count;
1304         atomic_t                s_active;
1305 #ifdef CONFIG_SECURITY
1306         void                    *s_security;
1307 #endif
1308         const struct xattr_handler **s_xattr;
1309 
1310         const struct fscrypt_operations *s_cop;
1311 
1312         struct hlist_bl_head    s_anon;         /* anonymous dentries for (nfs) exporting */
1313         struct list_head        s_mounts;       /* list of mounts; _not_ for fs use */
1314         struct block_device     *s_bdev;
1315         struct backing_dev_info *s_bdi;
1316         struct mtd_info         *s_mtd;
1317         struct hlist_node       s_instances;
1318         unsigned int            s_quota_types;  /* Bitmask of supported quota types */
1319         struct quota_info       s_dquot;        /* Diskquota specific options */
1320 
1321         struct sb_writers       s_writers;
1322 
1323         char s_id[32];                          /* Informational name */
1324         u8 s_uuid[16];                          /* UUID */
1325 
1326         void                    *s_fs_info;     /* Filesystem private info */
1327         unsigned int            s_max_links;
1328         fmode_t                 s_mode;
1329 
1330         /* Granularity of c/m/atime in ns.
1331            Cannot be worse than a second */
1332         u32                s_time_gran;
1333 
1334         /*
1335          * The next field is for VFS *only*. No filesystems have any business
1336          * even looking at it. You had been warned.
1337          */
1338         struct mutex s_vfs_rename_mutex;        /* Kludge */
1339 
1340         /*
1341          * Filesystem subtype.  If non-empty the filesystem type field
1342          * in /proc/mounts will be "type.subtype"
1343          */
1344         char *s_subtype;
1345 
1346         /*
1347          * Saved mount options for lazy filesystems using
1348          * generic_show_options()
1349          */
1350         char __rcu *s_options;
1351         const struct dentry_operations *s_d_op; /* default d_op for dentries */
1352 
1353         /*
1354          * Saved pool identifier for cleancache (-1 means none)
1355          */
1356         int cleancache_poolid;
1357 
1358         struct shrinker s_shrink;       /* per-sb shrinker handle */
1359 
1360         /* Number of inodes with nlink == 0 but still referenced */
1361         atomic_long_t s_remove_count;
1362 
1363         /* Being remounted read-only */
1364         int s_readonly_remount;
1365 
1366         /* AIO completions deferred from interrupt context */
1367         struct workqueue_struct *s_dio_done_wq;
1368         struct hlist_head s_pins;
1369 
1370         /*
1371          * Owning user namespace and default context in which to
1372          * interpret filesystem uids, gids, quotas, device nodes,
1373          * xattrs and security labels.
1374          */
1375         struct user_namespace *s_user_ns;
1376 
1377         /*
1378          * Keep the lru lists last in the structure so they always sit on their
1379          * own individual cachelines.
1380          */
1381         struct list_lru         s_dentry_lru ____cacheline_aligned_in_smp;
1382         struct list_lru         s_inode_lru ____cacheline_aligned_in_smp;
1383         struct rcu_head         rcu;
1384         struct work_struct      destroy_work;
1385 
1386         struct mutex            s_sync_lock;    /* sync serialisation lock */
1387 
1388         /*
1389          * Indicates how deep in a filesystem stack this SB is
1390          */
1391         int s_stack_depth;
1392 
1393         /* s_inode_list_lock protects s_inodes */
1394         spinlock_t              s_inode_list_lock ____cacheline_aligned_in_smp;
1395         struct list_head        s_inodes;       /* all inodes */
1396 
1397         spinlock_t              s_inode_wblist_lock;
1398         struct list_head        s_inodes_wb;    /* writeback inodes */
1399 };
1400 
1401 /* Helper functions so that in most cases filesystems will
1402  * not need to deal directly with kuid_t and kgid_t and can
1403  * instead deal with the raw numeric values that are stored
1404  * in the filesystem.
1405  */
1406 static inline uid_t i_uid_read(const struct inode *inode)
1407 {
1408         return from_kuid(inode->i_sb->s_user_ns, inode->i_uid);
1409 }
1410 
1411 static inline gid_t i_gid_read(const struct inode *inode)
1412 {
1413         return from_kgid(inode->i_sb->s_user_ns, inode->i_gid);
1414 }
1415 
1416 static inline void i_uid_write(struct inode *inode, uid_t uid)
1417 {
1418         inode->i_uid = make_kuid(inode->i_sb->s_user_ns, uid);
1419 }
1420 
1421 static inline void i_gid_write(struct inode *inode, gid_t gid)
1422 {
1423         inode->i_gid = make_kgid(inode->i_sb->s_user_ns, gid);
1424 }
1425 
1426 extern struct timespec current_fs_time(struct super_block *sb);
1427 extern struct timespec current_time(struct inode *inode);
1428 
1429 /*
1430  * Snapshotting support.
1431  */
1432 
1433 void __sb_end_write(struct super_block *sb, int level);
1434 int __sb_start_write(struct super_block *sb, int level, bool wait);
1435 
1436 #define __sb_writers_acquired(sb, lev)  \
1437         percpu_rwsem_acquire(&(sb)->s_writers.rw_sem[(lev)-1], 1, _THIS_IP_)
1438 #define __sb_writers_release(sb, lev)   \
1439         percpu_rwsem_release(&(sb)->s_writers.rw_sem[(lev)-1], 1, _THIS_IP_)
1440 
1441 /**
1442  * sb_end_write - drop write access to a superblock
1443  * @sb: the super we wrote to
1444  *
1445  * Decrement number of writers to the filesystem. Wake up possible waiters
1446  * wanting to freeze the filesystem.
1447  */
1448 static inline void sb_end_write(struct super_block *sb)
1449 {
1450         __sb_end_write(sb, SB_FREEZE_WRITE);
1451 }
1452 
1453 /**
1454  * sb_end_pagefault - drop write access to a superblock from a page fault
1455  * @sb: the super we wrote to
1456  *
1457  * Decrement number of processes handling write page fault to the filesystem.
1458  * Wake up possible waiters wanting to freeze the filesystem.
1459  */
1460 static inline void sb_end_pagefault(struct super_block *sb)
1461 {
1462         __sb_end_write(sb, SB_FREEZE_PAGEFAULT);
1463 }
1464 
1465 /**
1466  * sb_end_intwrite - drop write access to a superblock for internal fs purposes
1467  * @sb: the super we wrote to
1468  *
1469  * Decrement fs-internal number of writers to the filesystem.  Wake up possible
1470  * waiters wanting to freeze the filesystem.
1471  */
1472 static inline void sb_end_intwrite(struct super_block *sb)
1473 {
1474         __sb_end_write(sb, SB_FREEZE_FS);
1475 }
1476 
1477 /**
1478  * sb_start_write - get write access to a superblock
1479  * @sb: the super we write to
1480  *
1481  * When a process wants to write data or metadata to a file system (i.e. dirty
1482  * a page or an inode), it should embed the operation in a sb_start_write() -
1483  * sb_end_write() pair to get exclusion against file system freezing. This
1484  * function increments number of writers preventing freezing. If the file
1485  * system is already frozen, the function waits until the file system is
1486  * thawed.
1487  *
1488  * Since freeze protection behaves as a lock, users have to preserve
1489  * ordering of freeze protection and other filesystem locks. Generally,
1490  * freeze protection should be the outermost lock. In particular, we have:
1491  *
1492  * sb_start_write
1493  *   -> i_mutex                 (write path, truncate, directory ops, ...)
1494  *   -> s_umount                (freeze_super, thaw_super)
1495  */
1496 static inline void sb_start_write(struct super_block *sb)
1497 {
1498         __sb_start_write(sb, SB_FREEZE_WRITE, true);
1499 }
1500 
1501 static inline int sb_start_write_trylock(struct super_block *sb)
1502 {
1503         return __sb_start_write(sb, SB_FREEZE_WRITE, false);
1504 }
1505 
1506 /**
1507  * sb_start_pagefault - get write access to a superblock from a page fault
1508  * @sb: the super we write to
1509  *
1510  * When a process starts handling write page fault, it should embed the
1511  * operation into sb_start_pagefault() - sb_end_pagefault() pair to get
1512  * exclusion against file system freezing. This is needed since the page fault
1513  * is going to dirty a page. This function increments number of running page
1514  * faults preventing freezing. If the file system is already frozen, the
1515  * function waits until the file system is thawed.
1516  *
1517  * Since page fault freeze protection behaves as a lock, users have to preserve
1518  * ordering of freeze protection and other filesystem locks. It is advised to
1519  * put sb_start_pagefault() close to mmap_sem in lock ordering. Page fault
1520  * handling code implies lock dependency:
1521  *
1522  * mmap_sem
1523  *   -> sb_start_pagefault
1524  */
1525 static inline void sb_start_pagefault(struct super_block *sb)
1526 {
1527         __sb_start_write(sb, SB_FREEZE_PAGEFAULT, true);
1528 }
1529 
1530 /*
1531  * sb_start_intwrite - get write access to a superblock for internal fs purposes
1532  * @sb: the super we write to
1533  *
1534  * This is the third level of protection against filesystem freezing. It is
1535  * free for use by a filesystem. The only requirement is that it must rank
1536  * below sb_start_pagefault.
1537  *
1538  * For example filesystem can call sb_start_intwrite() when starting a
1539  * transaction which somewhat eases handling of freezing for internal sources
1540  * of filesystem changes (internal fs threads, discarding preallocation on file
1541  * close, etc.).
1542  */
1543 static inline void sb_start_intwrite(struct super_block *sb)
1544 {
1545         __sb_start_write(sb, SB_FREEZE_FS, true);
1546 }
1547 
1548 
1549 extern bool inode_owner_or_capable(const struct inode *inode);
1550 
1551 /*
1552  * VFS helper functions..
1553  */
1554 extern int vfs_create(struct inode *, struct dentry *, umode_t, bool);
1555 extern int vfs_mkdir(struct inode *, struct dentry *, umode_t);
1556 extern int vfs_mknod(struct inode *, struct dentry *, umode_t, dev_t);
1557 extern int vfs_symlink(struct inode *, struct dentry *, const char *);
1558 extern int vfs_link(struct dentry *, struct inode *, struct dentry *, struct inode **);
1559 extern int vfs_rmdir(struct inode *, struct dentry *);
1560 extern int vfs_unlink(struct inode *, struct dentry *, struct inode **);
1561 extern int vfs_rename(struct inode *, struct dentry *, struct inode *, struct dentry *, struct inode **, unsigned int);
1562 extern int vfs_whiteout(struct inode *, struct dentry *);
1563 
1564 /*
1565  * VFS file helper functions.
1566  */
1567 extern void inode_init_owner(struct inode *inode, const struct inode *dir,
1568                         umode_t mode);
1569 extern bool may_open_dev(const struct path *path);
1570 /*
1571  * VFS FS_IOC_FIEMAP helper definitions.
1572  */
1573 struct fiemap_extent_info {
1574         unsigned int fi_flags;          /* Flags as passed from user */
1575         unsigned int fi_extents_mapped; /* Number of mapped extents */
1576         unsigned int fi_extents_max;    /* Size of fiemap_extent array */
1577         struct fiemap_extent __user *fi_extents_start; /* Start of
1578                                                         fiemap_extent array */
1579 };
1580 int fiemap_fill_next_extent(struct fiemap_extent_info *info, u64 logical,
1581                             u64 phys, u64 len, u32 flags);
1582 int fiemap_check_flags(struct fiemap_extent_info *fieinfo, u32 fs_flags);
1583 
1584 /*
1585  * File types
1586  *
1587  * NOTE! These match bits 12..15 of stat.st_mode
1588  * (ie "(i_mode >> 12) & 15").
1589  */
1590 #define DT_UNKNOWN      0
1591 #define DT_FIFO         1
1592 #define DT_CHR          2
1593 #define DT_DIR          4
1594 #define DT_BLK          6
1595 #define DT_REG          8
1596 #define DT_LNK          10
1597 #define DT_SOCK         12
1598 #define DT_WHT          14
1599 
1600 /*
1601  * This is the "filldir" function type, used by readdir() to let
1602  * the kernel specify what kind of dirent layout it wants to have.
1603  * This allows the kernel to read directories into kernel space or
1604  * to have different dirent layouts depending on the binary type.
1605  */
1606 struct dir_context;
1607 typedef int (*filldir_t)(struct dir_context *, const char *, int, loff_t, u64,
1608                          unsigned);
1609 
1610 struct dir_context {
1611         const filldir_t actor;
1612         loff_t pos;
1613 };
1614 
1615 struct block_device_operations;
1616 
1617 /* These macros are for out of kernel modules to test that
1618  * the kernel supports the unlocked_ioctl and compat_ioctl
1619  * fields in struct file_operations. */
1620 #define HAVE_COMPAT_IOCTL 1
1621 #define HAVE_UNLOCKED_IOCTL 1
1622 
1623 /*
1624  * These flags let !MMU mmap() govern direct device mapping vs immediate
1625  * copying more easily for MAP_PRIVATE, especially for ROM filesystems.
1626  *
1627  * NOMMU_MAP_COPY:      Copy can be mapped (MAP_PRIVATE)
1628  * NOMMU_MAP_DIRECT:    Can be mapped directly (MAP_SHARED)
1629  * NOMMU_MAP_READ:      Can be mapped for reading
1630  * NOMMU_MAP_WRITE:     Can be mapped for writing
1631  * NOMMU_MAP_EXEC:      Can be mapped for execution
1632  */
1633 #define NOMMU_MAP_COPY          0x00000001
1634 #define NOMMU_MAP_DIRECT        0x00000008
1635 #define NOMMU_MAP_READ          VM_MAYREAD
1636 #define NOMMU_MAP_WRITE         VM_MAYWRITE
1637 #define NOMMU_MAP_EXEC          VM_MAYEXEC
1638 
1639 #define NOMMU_VMFLAGS \
1640         (NOMMU_MAP_READ | NOMMU_MAP_WRITE | NOMMU_MAP_EXEC)
1641 
1642 
1643 struct iov_iter;
1644 
1645 struct file_operations {
1646         struct module *owner;
1647         loff_t (*llseek) (struct file *, loff_t, int);
1648         ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);
1649         ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
1650         ssize_t (*read_iter) (struct kiocb *, struct iov_iter *);
1651         ssize_t (*write_iter) (struct kiocb *, struct iov_iter *);
1652         int (*iterate) (struct file *, struct dir_context *);
1653         int (*iterate_shared) (struct file *, struct dir_context *);
1654         unsigned int (*poll) (struct file *, struct poll_table_struct *);
1655         long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
1656         long (*compat_ioctl) (struct file *, unsigned int, unsigned long);
1657         int (*mmap) (struct file *, struct vm_area_struct *);
1658         int (*open) (struct inode *, struct file *);
1659         int (*flush) (struct file *, fl_owner_t id);
1660         int (*release) (struct inode *, struct file *);
1661         int (*fsync) (struct file *, loff_t, loff_t, int datasync);
1662         int (*fasync) (int, struct file *, int);
1663         int (*lock) (struct file *, int, struct file_lock *);
1664         ssize_t (*sendpage) (struct file *, struct page *, int, size_t, loff_t *, int);
1665         unsigned long (*get_unmapped_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
1666         int (*check_flags)(int);
1667         int (*flock) (struct file *, int, struct file_lock *);
1668         ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, loff_t *, size_t, unsigned int);
1669         ssize_t (*splice_read)(struct file *, loff_t *, struct pipe_inode_info *, size_t, unsigned int);
1670         int (*setlease)(struct file *, long, struct file_lock **, void **);
1671         long (*fallocate)(struct file *file, int mode, loff_t offset,
1672                           loff_t len);
1673         void (*show_fdinfo)(struct seq_file *m, struct file *f);
1674 #ifndef CONFIG_MMU
1675         unsigned (*mmap_capabilities)(struct file *);
1676 #endif
1677         ssize_t (*copy_file_range)(struct file *, loff_t, struct file *,
1678                         loff_t, size_t, unsigned int);
1679         int (*clone_file_range)(struct file *, loff_t, struct file *, loff_t,
1680                         u64);
1681         ssize_t (*dedupe_file_range)(struct file *, u64, u64, struct file *,
1682                         u64);
1683 };
1684 
1685 struct inode_operations {
1686         struct dentry * (*lookup) (struct inode *,struct dentry *, unsigned int);
1687         const char * (*get_link) (struct dentry *, struct inode *, struct delayed_call *);
1688         int (*permission) (struct inode *, int);
1689         struct posix_acl * (*get_acl)(struct inode *, int);
1690 
1691         int (*readlink) (struct dentry *, char __user *,int);
1692 
1693         int (*create) (struct inode *,struct dentry *, umode_t, bool);
1694         int (*link) (struct dentry *,struct inode *,struct dentry *);
1695         int (*unlink) (struct inode *,struct dentry *);
1696         int (*symlink) (struct inode *,struct dentry *,const char *);
1697         int (*mkdir) (struct inode *,struct dentry *,umode_t);
1698         int (*rmdir) (struct inode *,struct dentry *);
1699         int (*mknod) (struct inode *,struct dentry *,umode_t,dev_t);
1700         int (*rename) (struct inode *, struct dentry *,
1701                         struct inode *, struct dentry *, unsigned int);
1702         int (*setattr) (struct dentry *, struct iattr *);
1703         int (*getattr) (struct vfsmount *mnt, struct dentry *, struct kstat *);
1704         ssize_t (*listxattr) (struct dentry *, char *, size_t);
1705         int (*fiemap)(struct inode *, struct fiemap_extent_info *, u64 start,
1706                       u64 len);
1707         int (*update_time)(struct inode *, struct timespec *, int);
1708         int (*atomic_open)(struct inode *, struct dentry *,
1709                            struct file *, unsigned open_flag,
1710                            umode_t create_mode, int *opened);
1711         int (*tmpfile) (struct inode *, struct dentry *, umode_t);
1712         int (*set_acl)(struct inode *, struct posix_acl *, int);
1713 } ____cacheline_aligned;
1714 
1715 ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector,
1716                               unsigned long nr_segs, unsigned long fast_segs,
1717                               struct iovec *fast_pointer,
1718                               struct iovec **ret_pointer);
1719 
1720 extern ssize_t __vfs_read(struct file *, char __user *, size_t, loff_t *);
1721 extern ssize_t __vfs_write(struct file *, const char __user *, size_t, loff_t *);
1722 extern ssize_t vfs_read(struct file *, char __user *, size_t, loff_t *);
1723 extern ssize_t vfs_write(struct file *, const char __user *, size_t, loff_t *);
1724 extern ssize_t vfs_readv(struct file *, const struct iovec __user *,
1725                 unsigned long, loff_t *, int);
1726 extern ssize_t vfs_writev(struct file *, const struct iovec __user *,
1727                 unsigned long, loff_t *, int);
1728 extern ssize_t vfs_copy_file_range(struct file *, loff_t , struct file *,
1729                                    loff_t, size_t, unsigned int);
1730 extern int vfs_clone_file_prep_inodes(struct inode *inode_in, loff_t pos_in,
1731                                       struct inode *inode_out, loff_t pos_out,
1732                                       u64 *len, bool is_dedupe);
1733 extern int vfs_clone_file_range(struct file *file_in, loff_t pos_in,
1734                 struct file *file_out, loff_t pos_out, u64 len);
1735 extern int vfs_dedupe_file_range_compare(struct inode *src, loff_t srcoff,
1736                                          struct inode *dest, loff_t destoff,
1737                                          loff_t len, bool *is_same);
1738 extern int vfs_dedupe_file_range(struct file *file,
1739                                  struct file_dedupe_range *same);
1740 
1741 static inline int do_clone_file_range(struct file *file_in, loff_t pos_in,
1742                                       struct file *file_out, loff_t pos_out,
1743                                       u64 len)
1744 {
1745         int ret;
1746 
1747         sb_start_write(file_inode(file_out)->i_sb);
1748         ret = vfs_clone_file_range(file_in, pos_in, file_out, pos_out, len);
1749         sb_end_write(file_inode(file_out)->i_sb);
1750 
1751         return ret;
1752 }
1753 
1754 struct super_operations {
1755         struct inode *(*alloc_inode)(struct super_block *sb);
1756         void (*destroy_inode)(struct inode *);
1757 
1758         void (*dirty_inode) (struct inode *, int flags);
1759         int (*write_inode) (struct inode *, struct writeback_control *wbc);
1760         int (*drop_inode) (struct inode *);
1761         void (*evict_inode) (struct inode *);
1762         void (*put_super) (struct super_block *);
1763         int (*sync_fs)(struct super_block *sb, int wait);
1764         int (*freeze_super) (struct super_block *);
1765         int (*freeze_fs) (struct super_block *);
1766         int (*thaw_super) (struct super_block *);
1767         int (*unfreeze_fs) (struct super_block *);
1768         int (*statfs) (struct dentry *, struct kstatfs *);
1769         int (*remount_fs) (struct super_block *, int *, char *);
1770         void (*umount_begin) (struct super_block *);
1771 
1772         int (*show_options)(struct seq_file *, struct dentry *);
1773         int (*show_devname)(struct seq_file *, struct dentry *);
1774         int (*show_path)(struct seq_file *, struct dentry *);
1775         int (*show_stats)(struct seq_file *, struct dentry *);
1776 #ifdef CONFIG_QUOTA
1777         ssize_t (*quota_read)(struct super_block *, int, char *, size_t, loff_t);
1778         ssize_t (*quota_write)(struct super_block *, int, const char *, size_t, loff_t);
1779         struct dquot **(*get_dquots)(struct inode *);
1780 #endif
1781         int (*bdev_try_to_free_page)(struct super_block*, struct page*, gfp_t);
1782         long (*nr_cached_objects)(struct super_block *,
1783                                   struct shrink_control *);
1784         long (*free_cached_objects)(struct super_block *,
1785                                     struct shrink_control *);
1786 };
1787 
1788 /*
1789  * Inode flags - they have no relation to superblock flags now
1790  */
1791 #define S_SYNC          1       /* Writes are synced at once */
1792 #define S_NOATIME       2       /* Do not update access times */
1793 #define S_APPEND        4       /* Append-only file */
1794 #define S_IMMUTABLE     8       /* Immutable file */
1795 #define S_DEAD          16      /* removed, but still open directory */
1796 #define S_NOQUOTA       32      /* Inode is not counted to quota */
1797 #define S_DIRSYNC       64      /* Directory modifications are synchronous */
1798 #define S_NOCMTIME      128     /* Do not update file c/mtime */
1799 #define S_SWAPFILE      256     /* Do not truncate: swapon got its bmaps */
1800 #define S_PRIVATE       512     /* Inode is fs-internal */
1801 #define S_IMA           1024    /* Inode has an associated IMA struct */
1802 #define S_AUTOMOUNT     2048    /* Automount/referral quasi-directory */
1803 #define S_NOSEC         4096    /* no suid or xattr security attributes */
1804 #ifdef CONFIG_FS_DAX
1805 #define S_DAX           8192    /* Direct Access, avoiding the page cache */
1806 #else
1807 #define S_DAX           0       /* Make all the DAX code disappear */
1808 #endif
1809 
1810 /*
1811  * Note that nosuid etc flags are inode-specific: setting some file-system
1812  * flags just means all the inodes inherit those flags by default. It might be
1813  * possible to override it selectively if you really wanted to with some
1814  * ioctl() that is not currently implemented.
1815  *
1816  * Exception: MS_RDONLY is always applied to the entire file system.
1817  *
1818  * Unfortunately, it is possible to change a filesystems flags with it mounted
1819  * with files in use.  This means that all of the inodes will not have their
1820  * i_flags updated.  Hence, i_flags no longer inherit the superblock mount
1821  * flags, so these have to be checked separately. -- rmk@arm.uk.linux.org
1822  */
1823 #define __IS_FLG(inode, flg)    ((inode)->i_sb->s_flags & (flg))
1824 
1825 #define IS_RDONLY(inode)        ((inode)->i_sb->s_flags & MS_RDONLY)
1826 #define IS_SYNC(inode)          (__IS_FLG(inode, MS_SYNCHRONOUS) || \
1827                                         ((inode)->i_flags & S_SYNC))
1828 #define IS_DIRSYNC(inode)       (__IS_FLG(inode, MS_SYNCHRONOUS|MS_DIRSYNC) || \
1829                                         ((inode)->i_flags & (S_SYNC|S_DIRSYNC)))
1830 #define IS_MANDLOCK(inode)      __IS_FLG(inode, MS_MANDLOCK)
1831 #define IS_NOATIME(inode)       __IS_FLG(inode, MS_RDONLY|MS_NOATIME)
1832 #define IS_I_VERSION(inode)     __IS_FLG(inode, MS_I_VERSION)
1833 
1834 #define IS_NOQUOTA(inode)       ((inode)->i_flags & S_NOQUOTA)
1835 #define IS_APPEND(inode)        ((inode)->i_flags & S_APPEND)
1836 #define IS_IMMUTABLE(inode)     ((inode)->i_flags & S_IMMUTABLE)
1837 #define IS_POSIXACL(inode)      __IS_FLG(inode, MS_POSIXACL)
1838 
1839 #define IS_DEADDIR(inode)       ((inode)->i_flags & S_DEAD)
1840 #define IS_NOCMTIME(inode)      ((inode)->i_flags & S_NOCMTIME)
1841 #define IS_SWAPFILE(inode)      ((inode)->i_flags & S_SWAPFILE)
1842 #define IS_PRIVATE(inode)       ((inode)->i_flags & S_PRIVATE)
1843 #define IS_IMA(inode)           ((inode)->i_flags & S_IMA)
1844 #define IS_AUTOMOUNT(inode)     ((inode)->i_flags & S_AUTOMOUNT)
1845 #define IS_NOSEC(inode)         ((inode)->i_flags & S_NOSEC)
1846 #define IS_DAX(inode)           ((inode)->i_flags & S_DAX)
1847 
1848 #define IS_WHITEOUT(inode)      (S_ISCHR(inode->i_mode) && \
1849                                  (inode)->i_rdev == WHITEOUT_DEV)
1850 
1851 static inline bool HAS_UNMAPPED_ID(struct inode *inode)
1852 {
1853         return !uid_valid(inode->i_uid) || !gid_valid(inode->i_gid);
1854 }
1855 
1856 /*
1857  * Inode state bits.  Protected by inode->i_lock
1858  *
1859  * Three bits determine the dirty state of the inode, I_DIRTY_SYNC,
1860  * I_DIRTY_DATASYNC and I_DIRTY_PAGES.
1861  *
1862  * Four bits define the lifetime of an inode.  Initially, inodes are I_NEW,
1863  * until that flag is cleared.  I_WILL_FREE, I_FREEING and I_CLEAR are set at
1864  * various stages of removing an inode.
1865  *
1866  * Two bits are used for locking and completion notification, I_NEW and I_SYNC.
1867  *
1868  * I_DIRTY_SYNC         Inode is dirty, but doesn't have to be written on
1869  *                      fdatasync().  i_atime is the usual cause.
1870  * I_DIRTY_DATASYNC     Data-related inode changes pending. We keep track of
1871  *                      these changes separately from I_DIRTY_SYNC so that we
1872  *                      don't have to write inode on fdatasync() when only
1873  *                      mtime has changed in it.
1874  * I_DIRTY_PAGES        Inode has dirty pages.  Inode itself may be clean.
1875  * I_NEW                Serves as both a mutex and completion notification.
1876  *                      New inodes set I_NEW.  If two processes both create
1877  *                      the same inode, one of them will release its inode and
1878  *                      wait for I_NEW to be released before returning.
1879  *                      Inodes in I_WILL_FREE, I_FREEING or I_CLEAR state can
1880  *                      also cause waiting on I_NEW, without I_NEW actually
1881  *                      being set.  find_inode() uses this to prevent returning
1882  *                      nearly-dead inodes.
1883  * I_WILL_FREE          Must be set when calling write_inode_now() if i_count
1884  *                      is zero.  I_FREEING must be set when I_WILL_FREE is
1885  *                      cleared.
1886  * I_FREEING            Set when inode is about to be freed but still has dirty
1887  *                      pages or buffers attached or the inode itself is still
1888  *                      dirty.
1889  * I_CLEAR              Added by clear_inode().  In this state the inode is
1890  *                      clean and can be destroyed.  Inode keeps I_FREEING.
1891  *
1892  *                      Inodes that are I_WILL_FREE, I_FREEING or I_CLEAR are
1893  *                      prohibited for many purposes.  iget() must wait for
1894  *                      the inode to be completely released, then create it
1895  *                      anew.  Other functions will just ignore such inodes,
1896  *                      if appropriate.  I_NEW is used for waiting.
1897  *
1898  * I_SYNC               Writeback of inode is running. The bit is set during
1899  *                      data writeback, and cleared with a wakeup on the bit
1900  *                      address once it is done. The bit is also used to pin
1901  *                      the inode in memory for flusher thread.
1902  *
1903  * I_REFERENCED         Marks the inode as recently references on the LRU list.
1904  *
1905  * I_DIO_WAKEUP         Never set.  Only used as a key for wait_on_bit().
1906  *
1907  * I_WB_SWITCH          Cgroup bdi_writeback switching in progress.  Used to
1908  *                      synchronize competing switching instances and to tell
1909  *                      wb stat updates to grab mapping->tree_lock.  See
1910  *                      inode_switch_wb_work_fn() for details.
1911  *
1912  * Q: What is the difference between I_WILL_FREE and I_FREEING?
1913  */
1914 #define I_DIRTY_SYNC            (1 << 0)
1915 #define I_DIRTY_DATASYNC        (1 << 1)
1916 #define I_DIRTY_PAGES           (1 << 2)
1917 #define __I_NEW                 3
1918 #define I_NEW                   (1 << __I_NEW)
1919 #define I_WILL_FREE             (1 << 4)
1920 #define I_FREEING               (1 << 5)
1921 #define I_CLEAR                 (1 << 6)
1922 #define __I_SYNC                7
1923 #define I_SYNC                  (1 << __I_SYNC)
1924 #define I_REFERENCED            (1 << 8)
1925 #define __I_DIO_WAKEUP          9
1926 #define I_DIO_WAKEUP            (1 << __I_DIO_WAKEUP)
1927 #define I_LINKABLE              (1 << 10)
1928 #define I_DIRTY_TIME            (1 << 11)
1929 #define __I_DIRTY_TIME_EXPIRED  12
1930 #define I_DIRTY_TIME_EXPIRED    (1 << __I_DIRTY_TIME_EXPIRED)
1931 #define I_WB_SWITCH             (1 << 13)
1932 
1933 #define I_DIRTY (I_DIRTY_SYNC | I_DIRTY_DATASYNC | I_DIRTY_PAGES)
1934 #define I_DIRTY_ALL (I_DIRTY | I_DIRTY_TIME)
1935 
1936 extern void __mark_inode_dirty(struct inode *, int);
1937 static inline void mark_inode_dirty(struct inode *inode)
1938 {
1939         __mark_inode_dirty(inode, I_DIRTY);
1940 }
1941 
1942 static inline void mark_inode_dirty_sync(struct inode *inode)
1943 {
1944         __mark_inode_dirty(inode, I_DIRTY_SYNC);
1945 }
1946 
1947 extern void inc_nlink(struct inode *inode);
1948 extern void drop_nlink(struct inode *inode);
1949 extern void clear_nlink(struct inode *inode);
1950 extern void set_nlink(struct inode *inode, unsigned int nlink);
1951 
1952 static inline void inode_inc_link_count(struct inode *inode)
1953 {
1954         inc_nlink(inode);
1955         mark_inode_dirty(inode);
1956 }
1957 
1958 static inline void inode_dec_link_count(struct inode *inode)
1959 {
1960         drop_nlink(inode);
1961         mark_inode_dirty(inode);
1962 }
1963 
1964 /**
1965  * inode_inc_iversion - increments i_version
1966  * @inode: inode that need to be updated
1967  *
1968  * Every time the inode is modified, the i_version field will be incremented.
1969  * The filesystem has to be mounted with i_version flag
1970  */
1971 
1972 static inline void inode_inc_iversion(struct inode *inode)
1973 {
1974        spin_lock(&inode->i_lock);
1975        inode->i_version++;
1976        spin_unlock(&inode->i_lock);
1977 }
1978 
1979 enum file_time_flags {
1980         S_ATIME = 1,
1981         S_MTIME = 2,
1982         S_CTIME = 4,
1983         S_VERSION = 8,
1984 };
1985 
1986 extern void touch_atime(const struct path *);
1987 static inline void file_accessed(struct file *file)
1988 {
1989         if (!(file->f_flags & O_NOATIME))
1990                 touch_atime(&file->f_path);
1991 }
1992 
1993 int sync_inode(struct inode *inode, struct writeback_control *wbc);
1994 int sync_inode_metadata(struct inode *inode, int wait);
1995 
1996 struct file_system_type {
1997         const char *name;
1998         int fs_flags;
1999 #define FS_REQUIRES_DEV         1 
2000 #define FS_BINARY_MOUNTDATA     2
2001 #define FS_HAS_SUBTYPE          4
2002 #define FS_USERNS_MOUNT         8       /* Can be mounted by userns root */
2003 #define FS_RENAME_DOES_D_MOVE   32768   /* FS will handle d_move() during rename() internally. */
2004         struct dentry *(*mount) (struct file_system_type *, int,
2005                        const char *, void *);
2006         void (*kill_sb) (struct super_block *);
2007         struct module *owner;
2008         struct file_system_type * next;
2009         struct hlist_head fs_supers;
2010 
2011         struct lock_class_key s_lock_key;
2012         struct lock_class_key s_umount_key;
2013         struct lock_class_key s_vfs_rename_key;
2014         struct lock_class_key s_writers_key[SB_FREEZE_LEVELS];
2015 
2016         struct lock_class_key i_lock_key;
2017         struct lock_class_key i_mutex_key;
2018         struct lock_class_key i_mutex_dir_key;
2019 };
2020 
2021 #define MODULE_ALIAS_FS(NAME) MODULE_ALIAS("fs-" NAME)
2022 
2023 extern struct dentry *mount_ns(struct file_system_type *fs_type,
2024         int flags, void *data, void *ns, struct user_namespace *user_ns,
2025         int (*fill_super)(struct super_block *, void *, int));
2026 extern struct dentry *mount_bdev(struct file_system_type *fs_type,
2027         int flags, const char *dev_name, void *data,
2028         int (*fill_super)(struct super_block *, void *, int));
2029 extern struct dentry *mount_single(struct file_system_type *fs_type,
2030         int flags, void *data,
2031         int (*fill_super)(struct super_block *, void *, int));
2032 extern struct dentry *mount_nodev(struct file_system_type *fs_type,
2033         int flags, void *data,
2034         int (*fill_super)(struct super_block *, void *, int));
2035 extern struct dentry *mount_subtree(struct vfsmount *mnt, const char *path);
2036 void generic_shutdown_super(struct super_block *sb);
2037 void kill_block_super(struct super_block *sb);
2038 void kill_anon_super(struct super_block *sb);
2039 void kill_litter_super(struct super_block *sb);
2040 void deactivate_super(struct super_block *sb);
2041 void deactivate_locked_super(struct super_block *sb);
2042 int set_anon_super(struct super_block *s, void *data);
2043 int get_anon_bdev(dev_t *);
2044 void free_anon_bdev(dev_t);
2045 struct super_block *sget_userns(struct file_system_type *type,
2046                         int (*test)(struct super_block *,void *),
2047                         int (*set)(struct super_block *,void *),
2048                         int flags, struct user_namespace *user_ns,
2049                         void *data);
2050 struct super_block *sget(struct file_system_type *type,
2051                         int (*test)(struct super_block *,void *),
2052                         int (*set)(struct super_block *,void *),
2053                         int flags, void *data);
2054 extern struct dentry *mount_pseudo_xattr(struct file_system_type *, char *,
2055                                          const struct super_operations *ops,
2056                                          const struct xattr_handler **xattr,
2057                                          const struct dentry_operations *dops,
2058                                          unsigned long);
2059 
2060 static inline struct dentry *
2061 mount_pseudo(struct file_system_type *fs_type, char *name,
2062              const struct super_operations *ops,
2063              const struct dentry_operations *dops, unsigned long magic)
2064 {
2065         return mount_pseudo_xattr(fs_type, name, ops, NULL, dops, magic);
2066 }
2067 
2068 /* Alas, no aliases. Too much hassle with bringing module.h everywhere */
2069 #define fops_get(fops) \
2070         (((fops) && try_module_get((fops)->owner) ? (fops) : NULL))
2071 #define fops_put(fops) \
2072         do { if (fops) module_put((fops)->owner); } while(0)
2073 /*
2074  * This one is to be used *ONLY* from ->open() instances.
2075  * fops must be non-NULL, pinned down *and* module dependencies
2076  * should be sufficient to pin the caller down as well.
2077  */
2078 #define replace_fops(f, fops) \
2079         do {    \
2080                 struct file *__file = (f); \
2081                 fops_put(__file->f_op); \
2082                 BUG_ON(!(__file->f_op = (fops))); \
2083         } while(0)
2084 
2085 extern int register_filesystem(struct file_system_type *);
2086 extern int unregister_filesystem(struct file_system_type *);
2087 extern struct vfsmount *kern_mount_data(struct file_system_type *, void *data);
2088 #define kern_mount(type) kern_mount_data(type, NULL)
2089 extern void kern_unmount(struct vfsmount *mnt);
2090 extern int may_umount_tree(struct vfsmount *);
2091 extern int may_umount(struct vfsmount *);
2092 extern long do_mount(const char *, const char __user *,
2093                      const char *, unsigned long, void *);
2094 extern struct vfsmount *collect_mounts(const struct path *);
2095 extern void drop_collected_mounts(struct vfsmount *);
2096 extern int iterate_mounts(int (*)(struct vfsmount *, void *), void *,
2097                           struct vfsmount *);
2098 extern int vfs_statfs(const struct path *, struct kstatfs *);
2099 extern int user_statfs(const char __user *, struct kstatfs *);
2100 extern int fd_statfs(int, struct kstatfs *);
2101 extern int vfs_ustat(dev_t, struct kstatfs *);
2102 extern int freeze_super(struct super_block *super);
2103 extern int thaw_super(struct super_block *super);
2104 extern bool our_mnt(struct vfsmount *mnt);
2105 
2106 extern int current_umask(void);
2107 
2108 extern void ihold(struct inode * inode);
2109 extern void iput(struct inode *);
2110 extern int generic_update_time(struct inode *, struct timespec *, int);
2111 
2112 /* /sys/fs */
2113 extern struct kobject *fs_kobj;
2114 
2115 #define MAX_RW_COUNT (INT_MAX & PAGE_MASK)
2116 
2117 #ifdef CONFIG_MANDATORY_FILE_LOCKING
2118 extern int locks_mandatory_locked(struct file *);
2119 extern int locks_mandatory_area(struct inode *, struct file *, loff_t, loff_t, unsigned char);
2120 
2121 /*
2122  * Candidates for mandatory locking have the setgid bit set
2123  * but no group execute bit -  an otherwise meaningless combination.
2124  */
2125 
2126 static inline int __mandatory_lock(struct inode *ino)
2127 {
2128         return (ino->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID;
2129 }
2130 
2131 /*
2132  * ... and these candidates should be on MS_MANDLOCK mounted fs,
2133  * otherwise these will be advisory locks
2134  */
2135 
2136 static inline int mandatory_lock(struct inode *ino)
2137 {
2138         return IS_MANDLOCK(ino) && __mandatory_lock(ino);
2139 }
2140 
2141 static inline int locks_verify_locked(struct file *file)
2142 {
2143         if (mandatory_lock(locks_inode(file)))
2144                 return locks_mandatory_locked(file);
2145         return 0;
2146 }
2147 
2148 static inline int locks_verify_truncate(struct inode *inode,
2149                                     struct file *f,
2150                                     loff_t size)
2151 {
2152         if (!inode->i_flctx || !mandatory_lock(inode))
2153                 return 0;
2154 
2155         if (size < inode->i_size) {
2156                 return locks_mandatory_area(inode, f, size, inode->i_size - 1,
2157                                 F_WRLCK);
2158         } else {
2159                 return locks_mandatory_area(inode, f, inode->i_size, size - 1,
2160                                 F_WRLCK);
2161         }
2162 }
2163 
2164 #else /* !CONFIG_MANDATORY_FILE_LOCKING */
2165 
2166 static inline int locks_mandatory_locked(struct file *file)
2167 {
2168         return 0;
2169 }
2170 
2171 static inline int locks_mandatory_area(struct inode *inode, struct file *filp,
2172                                        loff_t start, loff_t end, unsigned char type)
2173 {
2174         return 0;
2175 }
2176 
2177 static inline int __mandatory_lock(struct inode *inode)
2178 {
2179         return 0;
2180 }
2181 
2182 static inline int mandatory_lock(struct inode *inode)
2183 {
2184         return 0;
2185 }
2186 
2187 static inline int locks_verify_locked(struct file *file)
2188 {
2189         return 0;
2190 }
2191 
2192 static inline int locks_verify_truncate(struct inode *inode, struct file *filp,
2193                                         size_t size)
2194 {
2195         return 0;
2196 }
2197 
2198 #endif /* CONFIG_MANDATORY_FILE_LOCKING */
2199 
2200 
2201 #ifdef CONFIG_FILE_LOCKING
2202 static inline int break_lease(struct inode *inode, unsigned int mode)
2203 {
2204         /*
2205          * Since this check is lockless, we must ensure that any refcounts
2206          * taken are done before checking i_flctx->flc_lease. Otherwise, we
2207          * could end up racing with tasks trying to set a new lease on this
2208          * file.
2209          */
2210         smp_mb();
2211         if (inode->i_flctx && !list_empty_careful(&inode->i_flctx->flc_lease))
2212                 return __break_lease(inode, mode, FL_LEASE);
2213         return 0;
2214 }
2215 
2216 static inline int break_deleg(struct inode *inode, unsigned int mode)
2217 {
2218         /*
2219          * Since this check is lockless, we must ensure that any refcounts
2220          * taken are done before checking i_flctx->flc_lease. Otherwise, we
2221          * could end up racing with tasks trying to set a new lease on this
2222          * file.
2223          */
2224         smp_mb();
2225         if (inode->i_flctx && !list_empty_careful(&inode->i_flctx->flc_lease))
2226                 return __break_lease(inode, mode, FL_DELEG);
2227         return 0;
2228 }
2229 
2230 static inline int try_break_deleg(struct inode *inode, struct inode **delegated_inode)
2231 {
2232         int ret;
2233 
2234         ret = break_deleg(inode, O_WRONLY|O_NONBLOCK);
2235         if (ret == -EWOULDBLOCK && delegated_inode) {
2236                 *delegated_inode = inode;
2237                 ihold(inode);
2238         }
2239         return ret;
2240 }
2241 
2242 static inline int break_deleg_wait(struct inode **delegated_inode)
2243 {
2244         int ret;
2245 
2246         ret = break_deleg(*delegated_inode, O_WRONLY);
2247         iput(*delegated_inode);
2248         *delegated_inode = NULL;
2249         return ret;
2250 }
2251 
2252 static inline int break_layout(struct inode *inode, bool wait)
2253 {
2254         smp_mb();
2255         if (inode->i_flctx && !list_empty_careful(&inode->i_flctx->flc_lease))
2256                 return __break_lease(inode,
2257                                 wait ? O_WRONLY : O_WRONLY | O_NONBLOCK,
2258                                 FL_LAYOUT);
2259         return 0;
2260 }
2261 
2262 #else /* !CONFIG_FILE_LOCKING */
2263 static inline int break_lease(struct inode *inode, unsigned int mode)
2264 {
2265         return 0;
2266 }
2267 
2268 static inline int break_deleg(struct inode *inode, unsigned int mode)
2269 {
2270         return 0;
2271 }
2272 
2273 static inline int try_break_deleg(struct inode *inode, struct inode **delegated_inode)
2274 {
2275         return 0;
2276 }
2277 
2278 static inline int break_deleg_wait(struct inode **delegated_inode)
2279 {
2280         BUG();
2281         return 0;
2282 }
2283 
2284 static inline int break_layout(struct inode *inode, bool wait)
2285 {
2286         return 0;
2287 }
2288 
2289 #endif /* CONFIG_FILE_LOCKING */
2290 
2291 /* fs/open.c */
2292 struct audit_names;
2293 struct filename {
2294         const char              *name;  /* pointer to actual string */
2295         const __user char       *uptr;  /* original userland pointer */
2296         struct audit_names      *aname;
2297         int                     refcnt;
2298         const char              iname[];
2299 };
2300 
2301 extern long vfs_truncate(const struct path *, loff_t);
2302 extern int do_truncate(struct dentry *, loff_t start, unsigned int time_attrs,
2303                        struct file *filp);
2304 extern int vfs_fallocate(struct file *file, int mode, loff_t offset,
2305                         loff_t len);
2306 extern long do_sys_open(int dfd, const char __user *filename, int flags,
2307                         umode_t mode);
2308 extern struct file *file_open_name(struct filename *, int, umode_t);
2309 extern struct file *filp_open(const char *, int, umode_t);
2310 extern struct file *file_open_root(struct dentry *, struct vfsmount *,
2311                                    const char *, int, umode_t);
2312 extern struct file * dentry_open(const struct path *, int, const struct cred *);
2313 extern int filp_close(struct file *, fl_owner_t id);
2314 
2315 extern struct filename *getname_flags(const char __user *, int, int *);
2316 extern struct filename *getname(const char __user *);
2317 extern struct filename *getname_kernel(const char *);
2318 extern void putname(struct filename *name);
2319 
2320 enum {
2321         FILE_CREATED = 1,
2322         FILE_OPENED = 2
2323 };
2324 extern int finish_open(struct file *file, struct dentry *dentry,
2325                         int (*open)(struct inode *, struct file *),
2326                         int *opened);
2327 extern int finish_no_open(struct file *file, struct dentry *dentry);
2328 
2329 /* fs/ioctl.c */
2330 
2331 extern int ioctl_preallocate(struct file *filp, void __user *argp);
2332 
2333 /* fs/dcache.c */
2334 extern void __init vfs_caches_init_early(void);
2335 extern void __init vfs_caches_init(void);
2336 
2337 extern struct kmem_cache *names_cachep;
2338 
2339 #define __getname()             kmem_cache_alloc(names_cachep, GFP_KERNEL)
2340 #define __putname(name)         kmem_cache_free(names_cachep, (void *)(name))
2341 
2342 #ifdef CONFIG_BLOCK
2343 extern int register_blkdev(unsigned int, const char *);
2344 extern void unregister_blkdev(unsigned int, const char *);
2345 extern struct block_device *bdget(dev_t);
2346 extern struct block_device *bdgrab(struct block_device *bdev);
2347 extern void bd_set_size(struct block_device *, loff_t size);
2348 extern void bd_forget(struct inode *inode);
2349 extern void bdput(struct block_device *);
2350 extern void invalidate_bdev(struct block_device *);
2351 extern void iterate_bdevs(void (*)(struct block_device *, void *), void *);
2352 extern int sync_blockdev(struct block_device *bdev);
2353 extern void kill_bdev(struct block_device *);
2354 extern struct super_block *freeze_bdev(struct block_device *);
2355 extern void emergency_thaw_all(void);
2356 extern int thaw_bdev(struct block_device *bdev, struct super_block *sb);
2357 extern int fsync_bdev(struct block_device *);
2358 
2359 extern struct super_block *blockdev_superblock;
2360 
2361 static inline bool sb_is_blkdev_sb(struct super_block *sb)
2362 {
2363         return sb == blockdev_superblock;
2364 }
2365 #else
2366 static inline void bd_forget(struct inode *inode) {}
2367 static inline int sync_blockdev(struct block_device *bdev) { return 0; }
2368 static inline void kill_bdev(struct block_device *bdev) {}
2369 static inline void invalidate_bdev(struct block_device *bdev) {}
2370 
2371 static inline struct super_block *freeze_bdev(struct block_device *sb)
2372 {
2373         return NULL;
2374 }
2375 
2376 static inline int thaw_bdev(struct block_device *bdev, struct super_block *sb)
2377 {
2378         return 0;
2379 }
2380 
2381 static inline void iterate_bdevs(void (*f)(struct block_device *, void *), void *arg)
2382 {
2383 }
2384 
2385 static inline bool sb_is_blkdev_sb(struct super_block *sb)
2386 {
2387         return false;
2388 }
2389 #endif
2390 extern int sync_filesystem(struct super_block *);
2391 extern const struct file_operations def_blk_fops;
2392 extern const struct file_operations def_chr_fops;
2393 #ifdef CONFIG_BLOCK
2394 extern int ioctl_by_bdev(struct block_device *, unsigned, unsigned long);
2395 extern int blkdev_ioctl(struct block_device *, fmode_t, unsigned, unsigned long);
2396 extern long compat_blkdev_ioctl(struct file *, unsigned, unsigned long);
2397 extern int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder);
2398 extern struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
2399                                                void *holder);
2400 extern struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode,
2401                                               void *holder);
2402 extern void blkdev_put(struct block_device *bdev, fmode_t mode);
2403 extern int __blkdev_reread_part(struct block_device *bdev);
2404 extern int blkdev_reread_part(struct block_device *bdev);
2405 
2406 #ifdef CONFIG_SYSFS
2407 extern int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk);
2408 extern void bd_unlink_disk_holder(struct block_device *bdev,
2409                                   struct gendisk *disk);
2410 #else
2411 static inline int bd_link_disk_holder(struct block_device *bdev,
2412                                       struct gendisk *disk)
2413 {
2414         return 0;
2415 }
2416 static inline void bd_unlink_disk_holder(struct block_device *bdev,
2417                                          struct gendisk *disk)
2418 {
2419 }
2420 #endif
2421 #endif
2422 
2423 /* fs/char_dev.c */
2424 #define CHRDEV_MAJOR_HASH_SIZE  255
2425 /* Marks the bottom of the first segment of free char majors */
2426 #define CHRDEV_MAJOR_DYN_END 234
2427 extern int alloc_chrdev_region(dev_t *, unsigned, unsigned, const char *);
2428 extern int register_chrdev_region(dev_t, unsigned, const char *);
2429 extern int __register_chrdev(unsigned int major, unsigned int baseminor,
2430                              unsigned int count, const char *name,
2431                              const struct file_operations *fops);
2432 extern void __unregister_chrdev(unsigned int major, unsigned int baseminor,
2433                                 unsigned int count, const char *name);
2434 extern void unregister_chrdev_region(dev_t, unsigned);
2435 extern void chrdev_show(struct seq_file *,off_t);
2436 
2437 static inline int register_chrdev(unsigned int major, const char *name,
2438                                   const struct file_operations *fops)
2439 {
2440         return __register_chrdev(major, 0, 256, name, fops);
2441 }
2442 
2443 static inline void unregister_chrdev(unsigned int major, const char *name)
2444 {
2445         __unregister_chrdev(major, 0, 256, name);
2446 }
2447 
2448 /* fs/block_dev.c */
2449 #define BDEVNAME_SIZE   32      /* Largest string for a blockdev identifier */
2450 #define BDEVT_SIZE      10      /* Largest string for MAJ:MIN for blkdev */
2451 
2452 #ifdef CONFIG_BLOCK
2453 #define BLKDEV_MAJOR_HASH_SIZE  255
2454 extern const char *__bdevname(dev_t, char *buffer);
2455 extern const char *bdevname(struct block_device *bdev, char *buffer);
2456 extern struct block_device *lookup_bdev(const char *);
2457 extern void blkdev_show(struct seq_file *,off_t);
2458 
2459 #else
2460 #define BLKDEV_MAJOR_HASH_SIZE  0
2461 #endif
2462 
2463 extern void init_special_inode(struct inode *, umode_t, dev_t);
2464 
2465 /* Invalid inode operations -- fs/bad_inode.c */
2466 extern void make_bad_inode(struct inode *);
2467 extern bool is_bad_inode(struct inode *);
2468 
2469 #ifdef CONFIG_BLOCK
2470 extern void check_disk_size_change(struct gendisk *disk,
2471                                    struct block_device *bdev);
2472 extern int revalidate_disk(struct gendisk *);
2473 extern int check_disk_change(struct block_device *);
2474 extern int __invalidate_device(struct block_device *, bool);
2475 extern int invalidate_partition(struct gendisk *, int);
2476 #endif
2477 unsigned long invalidate_mapping_pages(struct address_space *mapping,
2478                                         pgoff_t start, pgoff_t end);
2479 
2480 static inline void invalidate_remote_inode(struct inode *inode)
2481 {
2482         if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
2483             S_ISLNK(inode->i_mode))
2484                 invalidate_mapping_pages(inode->i_mapping, 0, -1);
2485 }
2486 extern int invalidate_inode_pages2(struct address_space *mapping);
2487 extern int invalidate_inode_pages2_range(struct address_space *mapping,
2488                                          pgoff_t start, pgoff_t end);
2489 extern int write_inode_now(struct inode *, int);
2490 extern int filemap_fdatawrite(struct address_space *);
2491 extern int filemap_flush(struct address_space *);
2492 extern int filemap_fdatawait(struct address_space *);
2493 extern void filemap_fdatawait_keep_errors(struct address_space *);
2494 extern int filemap_fdatawait_range(struct address_space *, loff_t lstart,
2495                                    loff_t lend);
2496 extern int filemap_write_and_wait(struct address_space *mapping);
2497 extern int filemap_write_and_wait_range(struct address_space *mapping,
2498                                         loff_t lstart, loff_t lend);
2499 extern int __filemap_fdatawrite_range(struct address_space *mapping,
2500                                 loff_t start, loff_t end, int sync_mode);
2501 extern int filemap_fdatawrite_range(struct address_space *mapping,
2502                                 loff_t start, loff_t end);
2503 extern int filemap_check_errors(struct address_space *mapping);
2504 
2505 extern int vfs_fsync_range(struct file *file, loff_t start, loff_t end,
2506                            int datasync);
2507 extern int vfs_fsync(struct file *file, int datasync);
2508 
2509 /*
2510  * Sync the bytes written if this was a synchronous write.  Expect ki_pos
2511  * to already be updated for the write, and will return either the amount
2512  * of bytes passed in, or an error if syncing the file failed.
2513  */
2514 static inline ssize_t generic_write_sync(struct kiocb *iocb, ssize_t count)
2515 {
2516         if (iocb->ki_flags & IOCB_DSYNC) {
2517                 int ret = vfs_fsync_range(iocb->ki_filp,
2518                                 iocb->ki_pos - count, iocb->ki_pos - 1,
2519                                 (iocb->ki_flags & IOCB_SYNC) ? 0 : 1);
2520                 if (ret)
2521                         return ret;
2522         }
2523 
2524         return count;
2525 }
2526 
2527 extern void emergency_sync(void);
2528 extern void emergency_remount(void);
2529 #ifdef CONFIG_BLOCK
2530 extern sector_t bmap(struct inode *, sector_t);
2531 #endif
2532 extern int notify_change(struct dentry *, struct iattr *, struct inode **);
2533 extern int inode_permission(struct inode *, int);
2534 extern int __inode_permission(struct inode *, int);
2535 extern int generic_permission(struct inode *, int);
2536 extern int __check_sticky(struct inode *dir, struct inode *inode);
2537 
2538 static inline bool execute_ok(struct inode *inode)
2539 {
2540         return (inode->i_mode & S_IXUGO) || S_ISDIR(inode->i_mode);
2541 }
2542 
2543 static inline void file_start_write(struct file *file)
2544 {
2545         if (!S_ISREG(file_inode(file)->i_mode))
2546                 return;
2547         __sb_start_write(file_inode(file)->i_sb, SB_FREEZE_WRITE, true);
2548 }
2549 
2550 static inline bool file_start_write_trylock(struct file *file)
2551 {
2552         if (!S_ISREG(file_inode(file)->i_mode))
2553                 return true;
2554         return __sb_start_write(file_inode(file)->i_sb, SB_FREEZE_WRITE, false);
2555 }
2556 
2557 static inline void file_end_write(struct file *file)
2558 {
2559         if (!S_ISREG(file_inode(file)->i_mode))
2560                 return;
2561         __sb_end_write(file_inode(file)->i_sb, SB_FREEZE_WRITE);
2562 }
2563 
2564 /*
2565  * get_write_access() gets write permission for a file.
2566  * put_write_access() releases this write permission.
2567  * This is used for regular files.
2568  * We cannot support write (and maybe mmap read-write shared) accesses and
2569  * MAP_DENYWRITE mmappings simultaneously. The i_writecount field of an inode
2570  * can have the following values:
2571  * 0: no writers, no VM_DENYWRITE mappings
2572  * < 0: (-i_writecount) vm_area_structs with VM_DENYWRITE set exist
2573  * > 0: (i_writecount) users are writing to the file.
2574  *
2575  * Normally we operate on that counter with atomic_{inc,dec} and it's safe
2576  * except for the cases where we don't hold i_writecount yet. Then we need to
2577  * use {get,deny}_write_access() - these functions check the sign and refuse
2578  * to do the change if sign is wrong.
2579  */
2580 static inline int get_write_access(struct inode *inode)
2581 {
2582         return atomic_inc_unless_negative(&inode->i_writecount) ? 0 : -ETXTBSY;
2583 }
2584 static inline int deny_write_access(struct file *file)
2585 {
2586         struct inode *inode = file_inode(file);
2587         return atomic_dec_unless_positive(&inode->i_writecount) ? 0 : -ETXTBSY;
2588 }
2589 static inline void put_write_access(struct inode * inode)
2590 {
2591         atomic_dec(&inode->i_writecount);
2592 }
2593 static inline void allow_write_access(struct file *file)
2594 {
2595         if (file)
2596                 atomic_inc(&file_inode(file)->i_writecount);
2597 }
2598 static inline bool inode_is_open_for_write(const struct inode *inode)
2599 {
2600         return atomic_read(&inode->i_writecount) > 0;
2601 }
2602 
2603 #ifdef CONFIG_IMA
2604 static inline void i_readcount_dec(struct inode *inode)
2605 {
2606         BUG_ON(!atomic_read(&inode->i_readcount));
2607         atomic_dec(&inode->i_readcount);
2608 }
2609 static inline void i_readcount_inc(struct inode *inode)
2610 {
2611         atomic_inc(&inode->i_readcount);
2612 }
2613 #else
2614 static inline void i_readcount_dec(struct inode *inode)
2615 {
2616         return;
2617 }
2618 static inline void i_readcount_inc(struct inode *inode)
2619 {
2620         return;
2621 }
2622 #endif
2623 extern int do_pipe_flags(int *, int);
2624 
2625 #define __kernel_read_file_id(id) \
2626         id(UNKNOWN, unknown)            \
2627         id(FIRMWARE, firmware)          \
2628         id(FIRMWARE_PREALLOC_BUFFER, firmware)  \
2629         id(MODULE, kernel-module)               \
2630         id(KEXEC_IMAGE, kexec-image)            \
2631         id(KEXEC_INITRAMFS, kexec-initramfs)    \
2632         id(POLICY, security-policy)             \
2633         id(MAX_ID, )
2634 
2635 #define __fid_enumify(ENUM, dummy) READING_ ## ENUM,
2636 #define __fid_stringify(dummy, str) #str,
2637 
2638 enum kernel_read_file_id {
2639         __kernel_read_file_id(__fid_enumify)
2640 };
2641 
2642 static const char * const kernel_read_file_str[] = {
2643         __kernel_read_file_id(__fid_stringify)
2644 };
2645 
2646 static inline const char *kernel_read_file_id_str(enum kernel_read_file_id id)
2647 {
2648         if (id < 0 || id >= READING_MAX_ID)
2649                 return kernel_read_file_str[READING_UNKNOWN];
2650 
2651         return kernel_read_file_str[id];
2652 }
2653 
2654 extern int kernel_read(struct file *, loff_t, char *, unsigned long);
2655 extern int kernel_read_file(struct file *, void **, loff_t *, loff_t,
2656                             enum kernel_read_file_id);
2657 extern int kernel_read_file_from_path(char *, void **, loff_t *, loff_t,
2658                                       enum kernel_read_file_id);
2659 extern int kernel_read_file_from_fd(int, void **, loff_t *, loff_t,
2660                                     enum kernel_read_file_id);
2661 extern ssize_t kernel_write(struct file *, const char *, size_t, loff_t);
2662 extern ssize_t __kernel_write(struct file *, const char *, size_t, loff_t *);
2663 extern struct file * open_exec(const char *);
2664  
2665 /* fs/dcache.c -- generic fs support functions */
2666 extern bool is_subdir(struct dentry *, struct dentry *);
2667 extern bool path_is_under(const struct path *, const struct path *);
2668 
2669 extern char *file_path(struct file *, char *, int);
2670 
2671 #include <linux/err.h>
2672 
2673 /* needed for stackable file system support */
2674 extern loff_t default_llseek(struct file *file, loff_t offset, int whence);
2675 
2676 extern loff_t vfs_llseek(struct file *file, loff_t offset, int whence);
2677 
2678 extern int inode_init_always(struct super_block *, struct inode *);
2679 extern void inode_init_once(struct inode *);
2680 extern void address_space_init_once(struct address_space *mapping);
2681 extern struct inode * igrab(struct inode *);
2682 extern ino_t iunique(struct super_block *, ino_t);
2683 extern int inode_needs_sync(struct inode *inode);
2684 extern int generic_delete_inode(struct inode *inode);
2685 static inline int generic_drop_inode(struct inode *inode)
2686 {
2687         return !inode->i_nlink || inode_unhashed(inode);
2688 }
2689 
2690 extern struct inode *ilookup5_nowait(struct super_block *sb,
2691                 unsigned long hashval, int (*test)(struct inode *, void *),
2692                 void *data);
2693 extern struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
2694                 int (*test)(struct inode *, void *), void *data);
2695 extern struct inode *ilookup(struct super_block *sb, unsigned long ino);
2696 
2697 extern struct inode * iget5_locked(struct super_block *, unsigned long, int (*test)(struct inode *, void *), int (*set)(struct inode *, void *), void *);
2698 extern struct inode * iget_locked(struct super_block *, unsigned long);
2699 extern struct inode *find_inode_nowait(struct super_block *,
2700                                        unsigned long,
2701                                        int (*match)(struct inode *,
2702                                                     unsigned long, void *),
2703                                        void *data);
2704 extern int insert_inode_locked4(struct inode *, unsigned long, int (*test)(struct inode *, void *), void *);
2705 extern int insert_inode_locked(struct inode *);
2706 #ifdef CONFIG_DEBUG_LOCK_ALLOC
2707 extern void lockdep_annotate_inode_mutex_key(struct inode *inode);
2708 #else
2709 static inline void lockdep_annotate_inode_mutex_key(struct inode *inode) { };
2710 #endif
2711 extern void unlock_new_inode(struct inode *);
2712 extern unsigned int get_next_ino(void);
2713 
2714 extern void __iget(struct inode * inode);
2715 extern void iget_failed(struct inode *);
2716 extern void clear_inode(struct inode *);
2717 extern void __destroy_inode(struct inode *);
2718 extern struct inode *new_inode_pseudo(struct super_block *sb);
2719 extern struct inode *new_inode(struct super_block *sb);
2720 extern void free_inode_nonrcu(struct inode *inode);
2721 extern int should_remove_suid(struct dentry *);
2722 extern int file_remove_privs(struct file *);
2723 
2724 extern void __insert_inode_hash(struct inode *, unsigned long hashval);
2725 static inline void insert_inode_hash(struct inode *inode)
2726 {
2727         __insert_inode_hash(inode, inode->i_ino);
2728 }
2729 
2730 extern void __remove_inode_hash(struct inode *);
2731 static inline void remove_inode_hash(struct inode *inode)
2732 {
2733         if (!inode_unhashed(inode) && !hlist_fake(&inode->i_hash))
2734                 __remove_inode_hash(inode);
2735 }
2736 
2737 extern void inode_sb_list_add(struct inode *inode);
2738 
2739 #ifdef CONFIG_BLOCK
2740 extern int bdev_read_only(struct block_device *);
2741 #endif
2742 extern int set_blocksize(struct block_device *, int);
2743 extern int sb_set_blocksize(struct super_block *, int);
2744 extern int sb_min_blocksize(struct super_block *, int);
2745 
2746 extern int generic_file_mmap(struct file *, struct vm_area_struct *);
2747 extern int generic_file_readonly_mmap(struct file *, struct vm_area_struct *);
2748 extern ssize_t generic_write_checks(struct kiocb *, struct iov_iter *);
2749 extern ssize_t generic_file_read_iter(struct kiocb *, struct iov_iter *);
2750 extern ssize_t __generic_file_write_iter(struct kiocb *, struct iov_iter *);
2751 extern ssize_t generic_file_write_iter(struct kiocb *, struct iov_iter *);
2752 extern ssize_t generic_file_direct_write(struct kiocb *, struct iov_iter *);
2753 extern ssize_t generic_perform_write(struct file *, struct iov_iter *, loff_t);
2754 
2755 ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos);
2756 ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos);
2757 
2758 /* fs/block_dev.c */
2759 extern ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to);
2760 extern ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from);
2761 extern int blkdev_fsync(struct file *filp, loff_t start, loff_t end,
2762                         int datasync);
2763 extern void block_sync_page(struct page *page);
2764 
2765 /* fs/splice.c */
2766 extern ssize_t generic_file_splice_read(struct file *, loff_t *,
2767                 struct pipe_inode_info *, size_t, unsigned int);
2768 extern ssize_t iter_file_splice_write(struct pipe_inode_info *,
2769                 struct file *, loff_t *, size_t, unsigned int);
2770 extern ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe,
2771                 struct file *out, loff_t *, size_t len, unsigned int flags);
2772 extern long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
2773                 loff_t *opos, size_t len, unsigned int flags);
2774 
2775 
2776 extern void
2777 file_ra_state_init(struct file_ra_state *ra, struct address_space *mapping);
2778 extern loff_t noop_llseek(struct file *file, loff_t offset, int whence);
2779 extern loff_t no_llseek(struct file *file, loff_t offset, int whence);
2780 extern loff_t vfs_setpos(struct file *file, loff_t offset, loff_t maxsize);
2781 extern loff_t generic_file_llseek(struct file *file, loff_t offset, int whence);
2782 extern loff_t generic_file_llseek_size(struct file *file, loff_t offset,
2783                 int whence, loff_t maxsize, loff_t eof);
2784 extern loff_t fixed_size_llseek(struct file *file, loff_t offset,
2785                 int whence, loff_t size);
2786 extern loff_t no_seek_end_llseek_size(struct file *, loff_t, int, loff_t);
2787 extern loff_t no_seek_end_llseek(struct file *, loff_t, int);
2788 extern int generic_file_open(struct inode * inode, struct file * filp);
2789 extern int nonseekable_open(struct inode * inode, struct file * filp);
2790 
2791 #ifdef CONFIG_BLOCK
2792 typedef void (dio_submit_t)(struct bio *bio, struct inode *inode,
2793                             loff_t file_offset);
2794 
2795 enum {
2796         /* need locking between buffered and direct access */
2797         DIO_LOCKING     = 0x01,
2798 
2799         /* filesystem does not support filling holes */
2800         DIO_SKIP_HOLES  = 0x02,
2801 
2802         /* filesystem can handle aio writes beyond i_size */
2803         DIO_ASYNC_EXTEND = 0x04,
2804 
2805         /* inode/fs/bdev does not need truncate protection */
2806         DIO_SKIP_DIO_COUNT = 0x08,
2807 };
2808 
2809 void dio_end_io(struct bio *bio, int error);
2810 
2811 ssize_t __blockdev_direct_IO(struct kiocb *iocb, struct inode *inode,
2812                              struct block_device *bdev, struct iov_iter *iter,
2813                              get_block_t get_block,
2814                              dio_iodone_t end_io, dio_submit_t submit_io,
2815                              int flags);
2816 
2817 static inline ssize_t blockdev_direct_IO(struct kiocb *iocb,
2818                                          struct inode *inode,
2819                                          struct iov_iter *iter,
2820                                          get_block_t get_block)
2821 {
2822         return __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev, iter,
2823                         get_block, NULL, NULL, DIO_LOCKING | DIO_SKIP_HOLES);
2824 }
2825 #endif
2826 
2827 void inode_dio_wait(struct inode *inode);
2828 
2829 /*
2830  * inode_dio_begin - signal start of a direct I/O requests
2831  * @inode: inode the direct I/O happens on
2832  *
2833  * This is called once we've finished processing a direct I/O request,
2834  * and is used to wake up callers waiting for direct I/O to be quiesced.
2835  */
2836 static inline void inode_dio_begin(struct inode *inode)
2837 {
2838         atomic_inc(&inode->i_dio_count);
2839 }
2840 
2841 /*
2842  * inode_dio_end - signal finish of a direct I/O requests
2843  * @inode: inode the direct I/O happens on
2844  *
2845  * This is called once we've finished processing a direct I/O request,
2846  * and is used to wake up callers waiting for direct I/O to be quiesced.
2847  */
2848 static inline void inode_dio_end(struct inode *inode)
2849 {
2850         if (atomic_dec_and_test(&inode->i_dio_count))
2851                 wake_up_bit(&inode->i_state, __I_DIO_WAKEUP);
2852 }
2853 
2854 extern void inode_set_flags(struct inode *inode, unsigned int flags,
2855                             unsigned int mask);
2856 
2857 extern const struct file_operations generic_ro_fops;
2858 
2859 #define special_file(m) (S_ISCHR(m)||S_ISBLK(m)||S_ISFIFO(m)||S_ISSOCK(m))
2860 
2861 extern int readlink_copy(char __user *, int, const char *);
2862 extern int page_readlink(struct dentry *, char __user *, int);
2863 extern const char *page_get_link(struct dentry *, struct inode *,
2864                                  struct delayed_call *);
2865 extern void page_put_link(void *);
2866 extern int __page_symlink(struct inode *inode, const char *symname, int len,
2867                 int nofs);
2868 extern int page_symlink(struct inode *inode, const char *symname, int len);
2869 extern const struct inode_operations page_symlink_inode_operations;
2870 extern void kfree_link(void *);
2871 extern void generic_fillattr(struct inode *, struct kstat *);
2872 int vfs_getattr_nosec(struct path *path, struct kstat *stat);
2873 extern int vfs_getattr(struct path *, struct kstat *);
2874 void __inode_add_bytes(struct inode *inode, loff_t bytes);
2875 void inode_add_bytes(struct inode *inode, loff_t bytes);
2876 void __inode_sub_bytes(struct inode *inode, loff_t bytes);
2877 void inode_sub_bytes(struct inode *inode, loff_t bytes);
2878 loff_t inode_get_bytes(struct inode *inode);
2879 void inode_set_bytes(struct inode *inode, loff_t bytes);
2880 const char *simple_get_link(struct dentry *, struct inode *,
2881                             struct delayed_call *);
2882 extern const struct inode_operations simple_symlink_inode_operations;
2883 
2884 extern int iterate_dir(struct file *, struct dir_context *);
2885 
2886 extern int vfs_stat(const char __user *, struct kstat *);
2887 extern int vfs_lstat(const char __user *, struct kstat *);
2888 extern int vfs_fstat(unsigned int, struct kstat *);
2889 extern int vfs_fstatat(int , const char __user *, struct kstat *, int);
2890 extern const char *vfs_get_link(struct dentry *, struct delayed_call *);
2891 extern int vfs_readlink(struct dentry *, char __user *, int);
2892 
2893 extern int __generic_block_fiemap(struct inode *inode,
2894                                   struct fiemap_extent_info *fieinfo,
2895                                   loff_t start, loff_t len,
2896                                   get_block_t *get_block);
2897 extern int generic_block_fiemap(struct inode *inode,
2898                                 struct fiemap_extent_info *fieinfo, u64 start,
2899                                 u64 len, get_block_t *get_block);
2900 
2901 extern void get_filesystem(struct file_system_type *fs);
2902 extern void put_filesystem(struct file_system_type *fs);
2903 extern struct file_system_type *get_fs_type(const char *name);
2904 extern struct super_block *get_super(struct block_device *);
2905 extern struct super_block *get_super_thawed(struct block_device *);
2906 extern struct super_block *get_super_exclusive_thawed(struct block_device *bdev);
2907 extern struct super_block *get_active_super(struct block_device *bdev);
2908 extern void drop_super(struct super_block *sb);
2909 extern void drop_super_exclusive(struct super_block *sb);
2910 extern void iterate_supers(void (*)(struct super_block *, void *), void *);
2911 extern void iterate_supers_type(struct file_system_type *,
2912                                 void (*)(struct super_block *, void *), void *);
2913 
2914 extern int dcache_dir_open(struct inode *, struct file *);
2915 extern int dcache_dir_close(struct inode *, struct file *);
2916 extern loff_t dcache_dir_lseek(struct file *, loff_t, int);
2917 extern int dcache_readdir(struct file *, struct dir_context *);
2918 extern int simple_setattr(struct dentry *, struct iattr *);
2919 extern int simple_getattr(struct vfsmount *, struct dentry *, struct kstat *);
2920 extern int simple_statfs(struct dentry *, struct kstatfs *);
2921 extern int simple_open(struct inode *inode, struct file *file);
2922 extern int simple_link(struct dentry *, struct inode *, struct dentry *);
2923 extern int simple_unlink(struct inode *, struct dentry *);
2924 extern int simple_rmdir(struct inode *, struct dentry *);
2925 extern int simple_rename(struct inode *, struct dentry *,
2926                          struct inode *, struct dentry *, unsigned int);
2927 extern int noop_fsync(struct file *, loff_t, loff_t, int);
2928 extern int simple_empty(struct dentry *);
2929 extern int simple_readpage(struct file *file, struct page *page);
2930 extern int simple_write_begin(struct file *file, struct address_space *mapping,
2931                         loff_t pos, unsigned len, unsigned flags,
2932                         struct page **pagep, void **fsdata);
2933 extern int simple_write_end(struct file *file, struct address_space *mapping,
2934                         loff_t pos, unsigned len, unsigned copied,
2935                         struct page *page, void *fsdata);
2936 extern int always_delete_dentry(const struct dentry *);
2937 extern struct inode *alloc_anon_inode(struct super_block *);
2938 extern int simple_nosetlease(struct file *, long, struct file_lock **, void **);
2939 extern const struct dentry_operations simple_dentry_operations;
2940 
2941 extern struct dentry *simple_lookup(struct inode *, struct dentry *, unsigned int flags);
2942 extern ssize_t generic_read_dir(struct file *, char __user *, size_t, loff_t *);
2943 extern const struct file_operations simple_dir_operations;
2944 extern const struct inode_operations simple_dir_inode_operations;
2945 extern void make_empty_dir_inode(struct inode *inode);
2946 extern bool is_empty_dir_inode(struct inode *inode);
2947 struct tree_descr { char *name; const struct file_operations *ops; int mode; };
2948 struct dentry *d_alloc_name(struct dentry *, const char *);
2949 extern int simple_fill_super(struct super_block *, unsigned long, struct tree_descr *);
2950 extern int simple_pin_fs(struct file_system_type *, struct vfsmount **mount, int *count);
2951 extern void simple_release_fs(struct vfsmount **mount, int *count);
2952 
2953 extern ssize_t simple_read_from_buffer(void __user *to, size_t count,
2954                         loff_t *ppos, const void *from, size_t available);
2955 extern ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos,
2956                 const void __user *from, size_t count);
2957 
2958 extern int __generic_file_fsync(struct file *, loff_t, loff_t, int);
2959 extern int generic_file_fsync(struct file *, loff_t, loff_t, int);
2960 
2961 extern int generic_check_addressable(unsigned, u64);
2962 
2963 #ifdef CONFIG_MIGRATION
2964 extern int buffer_migrate_page(struct address_space *,
2965                                 struct page *, struct page *,
2966                                 enum migrate_mode);
2967 #else
2968 #define buffer_migrate_page NULL
2969 #endif
2970 
2971 extern int setattr_prepare(struct dentry *, struct iattr *);
2972 extern int inode_newsize_ok(const struct inode *, loff_t offset);
2973 extern void setattr_copy(struct inode *inode, const struct iattr *attr);
2974 
2975 extern int file_update_time(struct file *file);
2976 
2977 extern int generic_show_options(struct seq_file *m, struct dentry *root);
2978 extern void save_mount_options(struct super_block *sb, char *options);
2979 extern void replace_mount_options(struct super_block *sb, char *options);
2980 
2981 static inline bool io_is_direct(struct file *filp)
2982 {
2983         return (filp->f_flags & O_DIRECT) || IS_DAX(filp->f_mapping->host);
2984 }
2985 
2986 static inline int iocb_flags(struct file *file)
2987 {
2988         int res = 0;
2989         if (file->f_flags & O_APPEND)
2990                 res |= IOCB_APPEND;
2991         if (io_is_direct(file))
2992                 res |= IOCB_DIRECT;
2993         if ((file->f_flags & O_DSYNC) || IS_SYNC(file->f_mapping->host))
2994                 res |= IOCB_DSYNC;
2995         if (file->f_flags & __O_SYNC)
2996                 res |= IOCB_SYNC;
2997         return res;
2998 }
2999 
3000 static inline ino_t parent_ino(struct dentry *dentry)
3001 {
3002         ino_t res;
3003 
3004         /*
3005          * Don't strictly need d_lock here? If the parent ino could change
3006          * then surely we'd have a deeper race in the caller?
3007          */
3008         spin_lock(&dentry->d_lock);
3009         res = dentry->d_parent->d_inode->i_ino;
3010         spin_unlock(&dentry->d_lock);
3011         return res;
3012 }
3013 
3014 /* Transaction based IO helpers */
3015 
3016 /*
3017  * An argresp is stored in an allocated page and holds the
3018  * size of the argument or response, along with its content
3019  */
3020 struct simple_transaction_argresp {
3021         ssize_t size;
3022         char data[0];
3023 };
3024 
3025 #define SIMPLE_TRANSACTION_LIMIT (PAGE_SIZE - sizeof(struct simple_transaction_argresp))
3026 
3027 char *simple_transaction_get(struct file *file, const char __user *buf,
3028                                 size_t size);
3029 ssize_t simple_transaction_read(struct file *file, char __user *buf,
3030                                 size_t size, loff_t *pos);
3031 int simple_transaction_release(struct inode *inode, struct file *file);
3032 
3033 void simple_transaction_set(struct file *file, size_t n);
3034 
3035 /*
3036  * simple attribute files
3037  *
3038  * These attributes behave similar to those in sysfs:
3039  *
3040  * Writing to an attribute immediately sets a value, an open file can be
3041  * written to multiple times.
3042  *
3043  * Reading from an attribute creates a buffer from the value that might get
3044  * read with multiple read calls. When the attribute has been read
3045  * completely, no further read calls are possible until the file is opened
3046  * again.
3047  *
3048  * All attributes contain a text representation of a numeric value
3049  * that are accessed with the get() and set() functions.
3050  */
3051 #define DEFINE_SIMPLE_ATTRIBUTE(__fops, __get, __set, __fmt)            \
3052 static int __fops ## _open(struct inode *inode, struct file *file)      \
3053 {                                                                       \
3054         __simple_attr_check_format(__fmt, 0ull);                        \
3055         return simple_attr_open(inode, file, __get, __set, __fmt);      \
3056 }                                                                       \
3057 static const struct file_operations __fops = {                          \
3058         .owner   = THIS_MODULE,                                         \
3059         .open    = __fops ## _open,                                     \
3060         .release = simple_attr_release,                                 \
3061         .read    = simple_attr_read,                                    \
3062         .write   = simple_attr_write,                                   \
3063         .llseek  = generic_file_llseek,                                 \
3064 }
3065 
3066 static inline __printf(1, 2)
3067 void __simple_attr_check_format(const char *fmt, ...)
3068 {
3069         /* don't do anything, just let the compiler check the arguments; */
3070 }
3071 
3072 int simple_attr_open(struct inode *inode, struct file *file,
3073                      int (*get)(void *, u64 *), int (*set)(void *, u64),
3074                      const char *fmt);
3075 int simple_attr_release(struct inode *inode, struct file *file);
3076 ssize_t simple_attr_read(struct file *file, char __user *buf,
3077                          size_t len, loff_t *ppos);
3078 ssize_t simple_attr_write(struct file *file, const char __user *buf,
3079                           size_t len, loff_t *ppos);
3080 
3081 struct ctl_table;
3082 int proc_nr_files(struct ctl_table *table, int write,
3083                   void __user *buffer, size_t *lenp, loff_t *ppos);
3084 int proc_nr_dentry(struct ctl_table *table, int write,
3085                   void __user *buffer, size_t *lenp, loff_t *ppos);
3086 int proc_nr_inodes(struct ctl_table *table, int write,
3087                    void __user *buffer, size_t *lenp, loff_t *ppos);
3088 int __init get_filesystem_list(char *buf);
3089 
3090 #define __FMODE_EXEC            ((__force int) FMODE_EXEC)
3091 #define __FMODE_NONOTIFY        ((__force int) FMODE_NONOTIFY)
3092 
3093 #define ACC_MODE(x) ("\004\002\006\006"[(x)&O_ACCMODE])
3094 #define OPEN_FMODE(flag) ((__force fmode_t)(((flag + 1) & O_ACCMODE) | \
3095                                             (flag & __FMODE_NONOTIFY)))
3096 
3097 static inline bool is_sxid(umode_t mode)
3098 {
3099         return (mode & S_ISUID) || ((mode & S_ISGID) && (mode & S_IXGRP));
3100 }
3101 
3102 static inline int check_sticky(struct inode *dir, struct inode *inode)
3103 {
3104         if (!(dir->i_mode & S_ISVTX))
3105                 return 0;
3106 
3107         return __check_sticky(dir, inode);
3108 }
3109 
3110 static inline void inode_has_no_xattr(struct inode *inode)
3111 {
3112         if (!is_sxid(inode->i_mode) && (inode->i_sb->s_flags & MS_NOSEC))
3113                 inode->i_flags |= S_NOSEC;
3114 }
3115 
3116 static inline bool is_root_inode(struct inode *inode)
3117 {
3118         return inode == inode->i_sb->s_root->d_inode;
3119 }
3120 
3121 static inline bool dir_emit(struct dir_context *ctx,
3122                             const char *name, int namelen,
3123                             u64 ino, unsigned type)
3124 {
3125         return ctx->actor(ctx, name, namelen, ctx->pos, ino, type) == 0;
3126 }
3127 static inline bool dir_emit_dot(struct file *file, struct dir_context *ctx)
3128 {
3129         return ctx->actor(ctx, ".", 1, ctx->pos,
3130                           file->f_path.dentry->d_inode->i_ino, DT_DIR) == 0;
3131 }
3132 static inline bool dir_emit_dotdot(struct file *file, struct dir_context *ctx)
3133 {
3134         return ctx->actor(ctx, "..", 2, ctx->pos,
3135                           parent_ino(file->f_path.dentry), DT_DIR) == 0;
3136 }
3137 static inline bool dir_emit_dots(struct file *file, struct dir_context *ctx)
3138 {
3139         if (ctx->pos == 0) {
3140                 if (!dir_emit_dot(file, ctx))
3141                         return false;
3142                 ctx->pos = 1;
3143         }
3144         if (ctx->pos == 1) {
3145                 if (!dir_emit_dotdot(file, ctx))
3146                         return false;
3147                 ctx->pos = 2;
3148         }
3149         return true;
3150 }
3151 static inline bool dir_relax(struct inode *inode)
3152 {
3153         inode_unlock(inode);
3154         inode_lock(inode);
3155         return !IS_DEADDIR(inode);
3156 }
3157 
3158 static inline bool dir_relax_shared(struct inode *inode)
3159 {
3160         inode_unlock_shared(inode);
3161         inode_lock_shared(inode);
3162         return !IS_DEADDIR(inode);
3163 }
3164 
3165 extern bool path_noexec(const struct path *path);
3166 extern void inode_nohighmem(struct inode *inode);
3167 
3168 #endif /* _LINUX_FS_H */
3169 

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