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Linux/include/linux/fs.h

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

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