xref: /linux/include/linux/fs.h (revision f73a058be5d70dd81a43f16b2bbff4b1576a7af8)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_FS_H
3 #define _LINUX_FS_H
4 
5 #include <linux/linkage.h>
6 #include <linux/wait_bit.h>
7 #include <linux/kdev_t.h>
8 #include <linux/dcache.h>
9 #include <linux/path.h>
10 #include <linux/stat.h>
11 #include <linux/cache.h>
12 #include <linux/list.h>
13 #include <linux/list_lru.h>
14 #include <linux/llist.h>
15 #include <linux/radix-tree.h>
16 #include <linux/xarray.h>
17 #include <linux/rbtree.h>
18 #include <linux/init.h>
19 #include <linux/pid.h>
20 #include <linux/bug.h>
21 #include <linux/mutex.h>
22 #include <linux/rwsem.h>
23 #include <linux/mm_types.h>
24 #include <linux/capability.h>
25 #include <linux/semaphore.h>
26 #include <linux/fcntl.h>
27 #include <linux/rculist_bl.h>
28 #include <linux/atomic.h>
29 #include <linux/shrinker.h>
30 #include <linux/migrate_mode.h>
31 #include <linux/uidgid.h>
32 #include <linux/lockdep.h>
33 #include <linux/percpu-rwsem.h>
34 #include <linux/workqueue.h>
35 #include <linux/delayed_call.h>
36 #include <linux/uuid.h>
37 #include <linux/errseq.h>
38 #include <linux/ioprio.h>
39 #include <linux/fs_types.h>
40 #include <linux/build_bug.h>
41 #include <linux/stddef.h>
42 #include <linux/mount.h>
43 #include <linux/cred.h>
44 #include <linux/mnt_idmapping.h>
45 #include <linux/slab.h>
46 #include <linux/maple_tree.h>
47 #include <linux/rw_hint.h>
48 
49 #include <asm/byteorder.h>
50 #include <uapi/linux/fs.h>
51 
52 struct backing_dev_info;
53 struct bdi_writeback;
54 struct bio;
55 struct io_comp_batch;
56 struct export_operations;
57 struct fiemap_extent_info;
58 struct hd_geometry;
59 struct iovec;
60 struct kiocb;
61 struct kobject;
62 struct pipe_inode_info;
63 struct poll_table_struct;
64 struct kstatfs;
65 struct vm_area_struct;
66 struct vfsmount;
67 struct cred;
68 struct swap_info_struct;
69 struct seq_file;
70 struct workqueue_struct;
71 struct iov_iter;
72 struct fscrypt_inode_info;
73 struct fscrypt_operations;
74 struct fsverity_info;
75 struct fsverity_operations;
76 struct fsnotify_mark_connector;
77 struct fsnotify_sb_info;
78 struct fs_context;
79 struct fs_parameter_spec;
80 struct fileattr;
81 struct iomap_ops;
82 
83 extern void __init inode_init(void);
84 extern void __init inode_init_early(void);
85 extern void __init files_init(void);
86 extern void __init files_maxfiles_init(void);
87 
88 extern unsigned long get_max_files(void);
89 extern unsigned int sysctl_nr_open;
90 
91 typedef __kernel_rwf_t rwf_t;
92 
93 struct buffer_head;
94 typedef int (get_block_t)(struct inode *inode, sector_t iblock,
95 			struct buffer_head *bh_result, int create);
96 typedef int (dio_iodone_t)(struct kiocb *iocb, loff_t offset,
97 			ssize_t bytes, void *private);
98 
99 #define MAY_EXEC		0x00000001
100 #define MAY_WRITE		0x00000002
101 #define MAY_READ		0x00000004
102 #define MAY_APPEND		0x00000008
103 #define MAY_ACCESS		0x00000010
104 #define MAY_OPEN		0x00000020
105 #define MAY_CHDIR		0x00000040
106 /* called from RCU mode, don't block */
107 #define MAY_NOT_BLOCK		0x00000080
108 
109 /*
110  * flags in file.f_mode.  Note that FMODE_READ and FMODE_WRITE must correspond
111  * to O_WRONLY and O_RDWR via the strange trick in do_dentry_open()
112  */
113 
114 /* file is open for reading */
115 #define FMODE_READ		((__force fmode_t)(1 << 0))
116 /* file is open for writing */
117 #define FMODE_WRITE		((__force fmode_t)(1 << 1))
118 /* file is seekable */
119 #define FMODE_LSEEK		((__force fmode_t)(1 << 2))
120 /* file can be accessed using pread */
121 #define FMODE_PREAD		((__force fmode_t)(1 << 3))
122 /* file can be accessed using pwrite */
123 #define FMODE_PWRITE		((__force fmode_t)(1 << 4))
124 /* File is opened for execution with sys_execve / sys_uselib */
125 #define FMODE_EXEC		((__force fmode_t)(1 << 5))
126 /* File writes are restricted (block device specific) */
127 #define FMODE_WRITE_RESTRICTED	((__force fmode_t)(1 << 6))
128 
129 /* FMODE_* bits 7 to 8 */
130 
131 /* 32bit hashes as llseek() offset (for directories) */
132 #define FMODE_32BITHASH         ((__force fmode_t)(1 << 9))
133 /* 64bit hashes as llseek() offset (for directories) */
134 #define FMODE_64BITHASH         ((__force fmode_t)(1 << 10))
135 
136 /*
137  * Don't update ctime and mtime.
138  *
139  * Currently a special hack for the XFS open_by_handle ioctl, but we'll
140  * hopefully graduate it to a proper O_CMTIME flag supported by open(2) soon.
141  */
142 #define FMODE_NOCMTIME		((__force fmode_t)(1 << 11))
143 
144 /* Expect random access pattern */
145 #define FMODE_RANDOM		((__force fmode_t)(1 << 12))
146 
147 /* File is huge (eg. /dev/mem): treat loff_t as unsigned */
148 #define FMODE_UNSIGNED_OFFSET	((__force fmode_t)(1 << 13))
149 
150 /* File is opened with O_PATH; almost nothing can be done with it */
151 #define FMODE_PATH		((__force fmode_t)(1 << 14))
152 
153 /* File needs atomic accesses to f_pos */
154 #define FMODE_ATOMIC_POS	((__force fmode_t)(1 << 15))
155 /* Write access to underlying fs */
156 #define FMODE_WRITER		((__force fmode_t)(1 << 16))
157 /* Has read method(s) */
158 #define FMODE_CAN_READ          ((__force fmode_t)(1 << 17))
159 /* Has write method(s) */
160 #define FMODE_CAN_WRITE         ((__force fmode_t)(1 << 18))
161 
162 #define FMODE_OPENED		((__force fmode_t)(1 << 19))
163 #define FMODE_CREATED		((__force fmode_t)(1 << 20))
164 
165 /* File is stream-like */
166 #define FMODE_STREAM		((__force fmode_t)(1 << 21))
167 
168 /* File supports DIRECT IO */
169 #define	FMODE_CAN_ODIRECT	((__force fmode_t)(1 << 22))
170 
171 #define	FMODE_NOREUSE		((__force fmode_t)(1 << 23))
172 
173 /* FMODE_* bit 24 */
174 
175 /* File is embedded in backing_file object */
176 #define FMODE_BACKING		((__force fmode_t)(1 << 25))
177 
178 /* File was opened by fanotify and shouldn't generate fanotify events */
179 #define FMODE_NONOTIFY		((__force fmode_t)(1 << 26))
180 
181 /* File is capable of returning -EAGAIN if I/O will block */
182 #define FMODE_NOWAIT		((__force fmode_t)(1 << 27))
183 
184 /* File represents mount that needs unmounting */
185 #define FMODE_NEED_UNMOUNT	((__force fmode_t)(1 << 28))
186 
187 /* File does not contribute to nr_files count */
188 #define FMODE_NOACCOUNT		((__force fmode_t)(1 << 29))
189 
190 /*
191  * Attribute flags.  These should be or-ed together to figure out what
192  * has been changed!
193  */
194 #define ATTR_MODE	(1 << 0)
195 #define ATTR_UID	(1 << 1)
196 #define ATTR_GID	(1 << 2)
197 #define ATTR_SIZE	(1 << 3)
198 #define ATTR_ATIME	(1 << 4)
199 #define ATTR_MTIME	(1 << 5)
200 #define ATTR_CTIME	(1 << 6)
201 #define ATTR_ATIME_SET	(1 << 7)
202 #define ATTR_MTIME_SET	(1 << 8)
203 #define ATTR_FORCE	(1 << 9) /* Not a change, but a change it */
204 #define ATTR_KILL_SUID	(1 << 11)
205 #define ATTR_KILL_SGID	(1 << 12)
206 #define ATTR_FILE	(1 << 13)
207 #define ATTR_KILL_PRIV	(1 << 14)
208 #define ATTR_OPEN	(1 << 15) /* Truncating from open(O_TRUNC) */
209 #define ATTR_TIMES_SET	(1 << 16)
210 #define ATTR_TOUCH	(1 << 17)
211 
212 /*
213  * Whiteout is represented by a char device.  The following constants define the
214  * mode and device number to use.
215  */
216 #define WHITEOUT_MODE 0
217 #define WHITEOUT_DEV 0
218 
219 /*
220  * This is the Inode Attributes structure, used for notify_change().  It
221  * uses the above definitions as flags, to know which values have changed.
222  * Also, in this manner, a Filesystem can look at only the values it cares
223  * about.  Basically, these are the attributes that the VFS layer can
224  * request to change from the FS layer.
225  *
226  * Derek Atkins <warlord@MIT.EDU> 94-10-20
227  */
228 struct iattr {
229 	unsigned int	ia_valid;
230 	umode_t		ia_mode;
231 	/*
232 	 * The two anonymous unions wrap structures with the same member.
233 	 *
234 	 * Filesystems raising FS_ALLOW_IDMAP need to use ia_vfs{g,u}id which
235 	 * are a dedicated type requiring the filesystem to use the dedicated
236 	 * helpers. Other filesystem can continue to use ia_{g,u}id until they
237 	 * have been ported.
238 	 *
239 	 * They always contain the same value. In other words FS_ALLOW_IDMAP
240 	 * pass down the same value on idmapped mounts as they would on regular
241 	 * mounts.
242 	 */
243 	union {
244 		kuid_t		ia_uid;
245 		vfsuid_t	ia_vfsuid;
246 	};
247 	union {
248 		kgid_t		ia_gid;
249 		vfsgid_t	ia_vfsgid;
250 	};
251 	loff_t		ia_size;
252 	struct timespec64 ia_atime;
253 	struct timespec64 ia_mtime;
254 	struct timespec64 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 read_folio().
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 /*
307  * oh the beauties of C type declarations.
308  */
309 struct page;
310 struct address_space;
311 struct writeback_control;
312 struct readahead_control;
313 
314 /* Match RWF_* bits to IOCB bits */
315 #define IOCB_HIPRI		(__force int) RWF_HIPRI
316 #define IOCB_DSYNC		(__force int) RWF_DSYNC
317 #define IOCB_SYNC		(__force int) RWF_SYNC
318 #define IOCB_NOWAIT		(__force int) RWF_NOWAIT
319 #define IOCB_APPEND		(__force int) RWF_APPEND
320 
321 /* non-RWF related bits - start at 16 */
322 #define IOCB_EVENTFD		(1 << 16)
323 #define IOCB_DIRECT		(1 << 17)
324 #define IOCB_WRITE		(1 << 18)
325 /* iocb->ki_waitq is valid */
326 #define IOCB_WAITQ		(1 << 19)
327 #define IOCB_NOIO		(1 << 20)
328 /* can use bio alloc cache */
329 #define IOCB_ALLOC_CACHE	(1 << 21)
330 /*
331  * IOCB_DIO_CALLER_COMP can be set by the iocb owner, to indicate that the
332  * iocb completion can be passed back to the owner for execution from a safe
333  * context rather than needing to be punted through a workqueue. If this
334  * flag is set, the bio completion handling may set iocb->dio_complete to a
335  * handler function and iocb->private to context information for that handler.
336  * The issuer should call the handler with that context information from task
337  * context to complete the processing of the iocb. Note that while this
338  * provides a task context for the dio_complete() callback, it should only be
339  * used on the completion side for non-IO generating completions. It's fine to
340  * call blocking functions from this callback, but they should not wait for
341  * unrelated IO (like cache flushing, new IO generation, etc).
342  */
343 #define IOCB_DIO_CALLER_COMP	(1 << 22)
344 /* kiocb is a read or write operation submitted by fs/aio.c. */
345 #define IOCB_AIO_RW		(1 << 23)
346 
347 /* for use in trace events */
348 #define TRACE_IOCB_STRINGS \
349 	{ IOCB_HIPRI,		"HIPRI" }, \
350 	{ IOCB_DSYNC,		"DSYNC" }, \
351 	{ IOCB_SYNC,		"SYNC" }, \
352 	{ IOCB_NOWAIT,		"NOWAIT" }, \
353 	{ IOCB_APPEND,		"APPEND" }, \
354 	{ IOCB_EVENTFD,		"EVENTFD"}, \
355 	{ IOCB_DIRECT,		"DIRECT" }, \
356 	{ IOCB_WRITE,		"WRITE" }, \
357 	{ IOCB_WAITQ,		"WAITQ" }, \
358 	{ IOCB_NOIO,		"NOIO" }, \
359 	{ IOCB_ALLOC_CACHE,	"ALLOC_CACHE" }, \
360 	{ IOCB_DIO_CALLER_COMP,	"CALLER_COMP" }
361 
362 struct kiocb {
363 	struct file		*ki_filp;
364 	loff_t			ki_pos;
365 	void (*ki_complete)(struct kiocb *iocb, long ret);
366 	void			*private;
367 	int			ki_flags;
368 	u16			ki_ioprio; /* See linux/ioprio.h */
369 	union {
370 		/*
371 		 * Only used for async buffered reads, where it denotes the
372 		 * page waitqueue associated with completing the read. Valid
373 		 * IFF IOCB_WAITQ is set.
374 		 */
375 		struct wait_page_queue	*ki_waitq;
376 		/*
377 		 * Can be used for O_DIRECT IO, where the completion handling
378 		 * is punted back to the issuer of the IO. May only be set
379 		 * if IOCB_DIO_CALLER_COMP is set by the issuer, and the issuer
380 		 * must then check for presence of this handler when ki_complete
381 		 * is invoked. The data passed in to this handler must be
382 		 * assigned to ->private when dio_complete is assigned.
383 		 */
384 		ssize_t (*dio_complete)(void *data);
385 	};
386 };
387 
388 static inline bool is_sync_kiocb(struct kiocb *kiocb)
389 {
390 	return kiocb->ki_complete == NULL;
391 }
392 
393 struct address_space_operations {
394 	int (*writepage)(struct page *page, struct writeback_control *wbc);
395 	int (*read_folio)(struct file *, struct folio *);
396 
397 	/* Write back some dirty pages from this mapping. */
398 	int (*writepages)(struct address_space *, struct writeback_control *);
399 
400 	/* Mark a folio dirty.  Return true if this dirtied it */
401 	bool (*dirty_folio)(struct address_space *, struct folio *);
402 
403 	void (*readahead)(struct readahead_control *);
404 
405 	int (*write_begin)(struct file *, struct address_space *mapping,
406 				loff_t pos, unsigned len,
407 				struct page **pagep, void **fsdata);
408 	int (*write_end)(struct file *, struct address_space *mapping,
409 				loff_t pos, unsigned len, unsigned copied,
410 				struct page *page, void *fsdata);
411 
412 	/* Unfortunately this kludge is needed for FIBMAP. Don't use it */
413 	sector_t (*bmap)(struct address_space *, sector_t);
414 	void (*invalidate_folio) (struct folio *, size_t offset, size_t len);
415 	bool (*release_folio)(struct folio *, gfp_t);
416 	void (*free_folio)(struct folio *folio);
417 	ssize_t (*direct_IO)(struct kiocb *, struct iov_iter *iter);
418 	/*
419 	 * migrate the contents of a folio to the specified target. If
420 	 * migrate_mode is MIGRATE_ASYNC, it must not block.
421 	 */
422 	int (*migrate_folio)(struct address_space *, struct folio *dst,
423 			struct folio *src, enum migrate_mode);
424 	int (*launder_folio)(struct folio *);
425 	bool (*is_partially_uptodate) (struct folio *, size_t from,
426 			size_t count);
427 	void (*is_dirty_writeback) (struct folio *, bool *dirty, bool *wb);
428 	int (*error_remove_folio)(struct address_space *, struct folio *);
429 
430 	/* swapfile support */
431 	int (*swap_activate)(struct swap_info_struct *sis, struct file *file,
432 				sector_t *span);
433 	void (*swap_deactivate)(struct file *file);
434 	int (*swap_rw)(struct kiocb *iocb, struct iov_iter *iter);
435 };
436 
437 extern const struct address_space_operations empty_aops;
438 
439 /**
440  * struct address_space - Contents of a cacheable, mappable object.
441  * @host: Owner, either the inode or the block_device.
442  * @i_pages: Cached pages.
443  * @invalidate_lock: Guards coherency between page cache contents and
444  *   file offset->disk block mappings in the filesystem during invalidates.
445  *   It is also used to block modification of page cache contents through
446  *   memory mappings.
447  * @gfp_mask: Memory allocation flags to use for allocating pages.
448  * @i_mmap_writable: Number of VM_SHARED, VM_MAYWRITE mappings.
449  * @nr_thps: Number of THPs in the pagecache (non-shmem only).
450  * @i_mmap: Tree of private and shared mappings.
451  * @i_mmap_rwsem: Protects @i_mmap and @i_mmap_writable.
452  * @nrpages: Number of page entries, protected by the i_pages lock.
453  * @writeback_index: Writeback starts here.
454  * @a_ops: Methods.
455  * @flags: Error bits and flags (AS_*).
456  * @wb_err: The most recent error which has occurred.
457  * @i_private_lock: For use by the owner of the address_space.
458  * @i_private_list: For use by the owner of the address_space.
459  * @i_private_data: For use by the owner of the address_space.
460  */
461 struct address_space {
462 	struct inode		*host;
463 	struct xarray		i_pages;
464 	struct rw_semaphore	invalidate_lock;
465 	gfp_t			gfp_mask;
466 	atomic_t		i_mmap_writable;
467 #ifdef CONFIG_READ_ONLY_THP_FOR_FS
468 	/* number of thp, only for non-shmem files */
469 	atomic_t		nr_thps;
470 #endif
471 	struct rb_root_cached	i_mmap;
472 	unsigned long		nrpages;
473 	pgoff_t			writeback_index;
474 	const struct address_space_operations *a_ops;
475 	unsigned long		flags;
476 	errseq_t		wb_err;
477 	spinlock_t		i_private_lock;
478 	struct list_head	i_private_list;
479 	struct rw_semaphore	i_mmap_rwsem;
480 	void *			i_private_data;
481 } __attribute__((aligned(sizeof(long)))) __randomize_layout;
482 	/*
483 	 * On most architectures that alignment is already the case; but
484 	 * must be enforced here for CRIS, to let the least significant bit
485 	 * of struct page's "mapping" pointer be used for PAGE_MAPPING_ANON.
486 	 */
487 
488 /* XArray tags, for tagging dirty and writeback pages in the pagecache. */
489 #define PAGECACHE_TAG_DIRTY	XA_MARK_0
490 #define PAGECACHE_TAG_WRITEBACK	XA_MARK_1
491 #define PAGECACHE_TAG_TOWRITE	XA_MARK_2
492 
493 /*
494  * Returns true if any of the pages in the mapping are marked with the tag.
495  */
496 static inline bool mapping_tagged(struct address_space *mapping, xa_mark_t tag)
497 {
498 	return xa_marked(&mapping->i_pages, tag);
499 }
500 
501 static inline void i_mmap_lock_write(struct address_space *mapping)
502 {
503 	down_write(&mapping->i_mmap_rwsem);
504 }
505 
506 static inline int i_mmap_trylock_write(struct address_space *mapping)
507 {
508 	return down_write_trylock(&mapping->i_mmap_rwsem);
509 }
510 
511 static inline void i_mmap_unlock_write(struct address_space *mapping)
512 {
513 	up_write(&mapping->i_mmap_rwsem);
514 }
515 
516 static inline int i_mmap_trylock_read(struct address_space *mapping)
517 {
518 	return down_read_trylock(&mapping->i_mmap_rwsem);
519 }
520 
521 static inline void i_mmap_lock_read(struct address_space *mapping)
522 {
523 	down_read(&mapping->i_mmap_rwsem);
524 }
525 
526 static inline void i_mmap_unlock_read(struct address_space *mapping)
527 {
528 	up_read(&mapping->i_mmap_rwsem);
529 }
530 
531 static inline void i_mmap_assert_locked(struct address_space *mapping)
532 {
533 	lockdep_assert_held(&mapping->i_mmap_rwsem);
534 }
535 
536 static inline void i_mmap_assert_write_locked(struct address_space *mapping)
537 {
538 	lockdep_assert_held_write(&mapping->i_mmap_rwsem);
539 }
540 
541 /*
542  * Might pages of this file be mapped into userspace?
543  */
544 static inline int mapping_mapped(struct address_space *mapping)
545 {
546 	return	!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root);
547 }
548 
549 /*
550  * Might pages of this file have been modified in userspace?
551  * Note that i_mmap_writable counts all VM_SHARED, VM_MAYWRITE vmas: do_mmap
552  * marks vma as VM_SHARED if it is shared, and the file was opened for
553  * writing i.e. vma may be mprotected writable even if now readonly.
554  *
555  * If i_mmap_writable is negative, no new writable mappings are allowed. You
556  * can only deny writable mappings, if none exists right now.
557  */
558 static inline int mapping_writably_mapped(struct address_space *mapping)
559 {
560 	return atomic_read(&mapping->i_mmap_writable) > 0;
561 }
562 
563 static inline int mapping_map_writable(struct address_space *mapping)
564 {
565 	return atomic_inc_unless_negative(&mapping->i_mmap_writable) ?
566 		0 : -EPERM;
567 }
568 
569 static inline void mapping_unmap_writable(struct address_space *mapping)
570 {
571 	atomic_dec(&mapping->i_mmap_writable);
572 }
573 
574 static inline int mapping_deny_writable(struct address_space *mapping)
575 {
576 	return atomic_dec_unless_positive(&mapping->i_mmap_writable) ?
577 		0 : -EBUSY;
578 }
579 
580 static inline void mapping_allow_writable(struct address_space *mapping)
581 {
582 	atomic_inc(&mapping->i_mmap_writable);
583 }
584 
585 /*
586  * Use sequence counter to get consistent i_size on 32-bit processors.
587  */
588 #if BITS_PER_LONG==32 && defined(CONFIG_SMP)
589 #include <linux/seqlock.h>
590 #define __NEED_I_SIZE_ORDERED
591 #define i_size_ordered_init(inode) seqcount_init(&inode->i_size_seqcount)
592 #else
593 #define i_size_ordered_init(inode) do { } while (0)
594 #endif
595 
596 struct posix_acl;
597 #define ACL_NOT_CACHED ((void *)(-1))
598 /*
599  * ACL_DONT_CACHE is for stacked filesystems, that rely on underlying fs to
600  * cache the ACL.  This also means that ->get_inode_acl() can be called in RCU
601  * mode with the LOOKUP_RCU flag.
602  */
603 #define ACL_DONT_CACHE ((void *)(-3))
604 
605 static inline struct posix_acl *
606 uncached_acl_sentinel(struct task_struct *task)
607 {
608 	return (void *)task + 1;
609 }
610 
611 static inline bool
612 is_uncached_acl(struct posix_acl *acl)
613 {
614 	return (long)acl & 1;
615 }
616 
617 #define IOP_FASTPERM	0x0001
618 #define IOP_LOOKUP	0x0002
619 #define IOP_NOFOLLOW	0x0004
620 #define IOP_XATTR	0x0008
621 #define IOP_DEFAULT_READLINK	0x0010
622 
623 /*
624  * Keep mostly read-only and often accessed (especially for
625  * the RCU path lookup and 'stat' data) fields at the beginning
626  * of the 'struct inode'
627  */
628 struct inode {
629 	umode_t			i_mode;
630 	unsigned short		i_opflags;
631 	kuid_t			i_uid;
632 	kgid_t			i_gid;
633 	unsigned int		i_flags;
634 
635 #ifdef CONFIG_FS_POSIX_ACL
636 	struct posix_acl	*i_acl;
637 	struct posix_acl	*i_default_acl;
638 #endif
639 
640 	const struct inode_operations	*i_op;
641 	struct super_block	*i_sb;
642 	struct address_space	*i_mapping;
643 
644 #ifdef CONFIG_SECURITY
645 	void			*i_security;
646 #endif
647 
648 	/* Stat data, not accessed from path walking */
649 	unsigned long		i_ino;
650 	/*
651 	 * Filesystems may only read i_nlink directly.  They shall use the
652 	 * following functions for modification:
653 	 *
654 	 *    (set|clear|inc|drop)_nlink
655 	 *    inode_(inc|dec)_link_count
656 	 */
657 	union {
658 		const unsigned int i_nlink;
659 		unsigned int __i_nlink;
660 	};
661 	dev_t			i_rdev;
662 	loff_t			i_size;
663 	struct timespec64	__i_atime;
664 	struct timespec64	__i_mtime;
665 	struct timespec64	__i_ctime; /* use inode_*_ctime accessors! */
666 	spinlock_t		i_lock;	/* i_blocks, i_bytes, maybe i_size */
667 	unsigned short          i_bytes;
668 	u8			i_blkbits;
669 	enum rw_hint		i_write_hint;
670 	blkcnt_t		i_blocks;
671 
672 #ifdef __NEED_I_SIZE_ORDERED
673 	seqcount_t		i_size_seqcount;
674 #endif
675 
676 	/* Misc */
677 	unsigned long		i_state;
678 	struct rw_semaphore	i_rwsem;
679 
680 	unsigned long		dirtied_when;	/* jiffies of first dirtying */
681 	unsigned long		dirtied_time_when;
682 
683 	struct hlist_node	i_hash;
684 	struct list_head	i_io_list;	/* backing dev IO list */
685 #ifdef CONFIG_CGROUP_WRITEBACK
686 	struct bdi_writeback	*i_wb;		/* the associated cgroup wb */
687 
688 	/* foreign inode detection, see wbc_detach_inode() */
689 	int			i_wb_frn_winner;
690 	u16			i_wb_frn_avg_time;
691 	u16			i_wb_frn_history;
692 #endif
693 	struct list_head	i_lru;		/* inode LRU list */
694 	struct list_head	i_sb_list;
695 	struct list_head	i_wb_list;	/* backing dev writeback list */
696 	union {
697 		struct hlist_head	i_dentry;
698 		struct rcu_head		i_rcu;
699 	};
700 	atomic64_t		i_version;
701 	atomic64_t		i_sequence; /* see futex */
702 	atomic_t		i_count;
703 	atomic_t		i_dio_count;
704 	atomic_t		i_writecount;
705 #if defined(CONFIG_IMA) || defined(CONFIG_FILE_LOCKING)
706 	atomic_t		i_readcount; /* struct files open RO */
707 #endif
708 	union {
709 		const struct file_operations	*i_fop;	/* former ->i_op->default_file_ops */
710 		void (*free_inode)(struct inode *);
711 	};
712 	struct file_lock_context	*i_flctx;
713 	struct address_space	i_data;
714 	struct list_head	i_devices;
715 	union {
716 		struct pipe_inode_info	*i_pipe;
717 		struct cdev		*i_cdev;
718 		char			*i_link;
719 		unsigned		i_dir_seq;
720 	};
721 
722 	__u32			i_generation;
723 
724 #ifdef CONFIG_FSNOTIFY
725 	__u32			i_fsnotify_mask; /* all events this inode cares about */
726 	struct fsnotify_mark_connector __rcu	*i_fsnotify_marks;
727 #endif
728 
729 #ifdef CONFIG_FS_ENCRYPTION
730 	struct fscrypt_inode_info	*i_crypt_info;
731 #endif
732 
733 #ifdef CONFIG_FS_VERITY
734 	struct fsverity_info	*i_verity_info;
735 #endif
736 
737 	void			*i_private; /* fs or device private pointer */
738 } __randomize_layout;
739 
740 struct timespec64 timestamp_truncate(struct timespec64 t, struct inode *inode);
741 
742 static inline unsigned int i_blocksize(const struct inode *node)
743 {
744 	return (1 << node->i_blkbits);
745 }
746 
747 static inline int inode_unhashed(struct inode *inode)
748 {
749 	return hlist_unhashed(&inode->i_hash);
750 }
751 
752 /*
753  * __mark_inode_dirty expects inodes to be hashed.  Since we don't
754  * want special inodes in the fileset inode space, we make them
755  * appear hashed, but do not put on any lists.  hlist_del()
756  * will work fine and require no locking.
757  */
758 static inline void inode_fake_hash(struct inode *inode)
759 {
760 	hlist_add_fake(&inode->i_hash);
761 }
762 
763 /*
764  * inode->i_mutex nesting subclasses for the lock validator:
765  *
766  * 0: the object of the current VFS operation
767  * 1: parent
768  * 2: child/target
769  * 3: xattr
770  * 4: second non-directory
771  * 5: second parent (when locking independent directories in rename)
772  *
773  * I_MUTEX_NONDIR2 is for certain operations (such as rename) which lock two
774  * non-directories at once.
775  *
776  * The locking order between these classes is
777  * parent[2] -> child -> grandchild -> normal -> xattr -> second non-directory
778  */
779 enum inode_i_mutex_lock_class
780 {
781 	I_MUTEX_NORMAL,
782 	I_MUTEX_PARENT,
783 	I_MUTEX_CHILD,
784 	I_MUTEX_XATTR,
785 	I_MUTEX_NONDIR2,
786 	I_MUTEX_PARENT2,
787 };
788 
789 static inline void inode_lock(struct inode *inode)
790 {
791 	down_write(&inode->i_rwsem);
792 }
793 
794 static inline void inode_unlock(struct inode *inode)
795 {
796 	up_write(&inode->i_rwsem);
797 }
798 
799 static inline void inode_lock_shared(struct inode *inode)
800 {
801 	down_read(&inode->i_rwsem);
802 }
803 
804 static inline void inode_unlock_shared(struct inode *inode)
805 {
806 	up_read(&inode->i_rwsem);
807 }
808 
809 static inline int inode_trylock(struct inode *inode)
810 {
811 	return down_write_trylock(&inode->i_rwsem);
812 }
813 
814 static inline int inode_trylock_shared(struct inode *inode)
815 {
816 	return down_read_trylock(&inode->i_rwsem);
817 }
818 
819 static inline int inode_is_locked(struct inode *inode)
820 {
821 	return rwsem_is_locked(&inode->i_rwsem);
822 }
823 
824 static inline void inode_lock_nested(struct inode *inode, unsigned subclass)
825 {
826 	down_write_nested(&inode->i_rwsem, subclass);
827 }
828 
829 static inline void inode_lock_shared_nested(struct inode *inode, unsigned subclass)
830 {
831 	down_read_nested(&inode->i_rwsem, subclass);
832 }
833 
834 static inline void filemap_invalidate_lock(struct address_space *mapping)
835 {
836 	down_write(&mapping->invalidate_lock);
837 }
838 
839 static inline void filemap_invalidate_unlock(struct address_space *mapping)
840 {
841 	up_write(&mapping->invalidate_lock);
842 }
843 
844 static inline void filemap_invalidate_lock_shared(struct address_space *mapping)
845 {
846 	down_read(&mapping->invalidate_lock);
847 }
848 
849 static inline int filemap_invalidate_trylock_shared(
850 					struct address_space *mapping)
851 {
852 	return down_read_trylock(&mapping->invalidate_lock);
853 }
854 
855 static inline void filemap_invalidate_unlock_shared(
856 					struct address_space *mapping)
857 {
858 	up_read(&mapping->invalidate_lock);
859 }
860 
861 void lock_two_nondirectories(struct inode *, struct inode*);
862 void unlock_two_nondirectories(struct inode *, struct inode*);
863 
864 void filemap_invalidate_lock_two(struct address_space *mapping1,
865 				 struct address_space *mapping2);
866 void filemap_invalidate_unlock_two(struct address_space *mapping1,
867 				   struct address_space *mapping2);
868 
869 
870 /*
871  * NOTE: in a 32bit arch with a preemptable kernel and
872  * an UP compile the i_size_read/write must be atomic
873  * with respect to the local cpu (unlike with preempt disabled),
874  * but they don't need to be atomic with respect to other cpus like in
875  * true SMP (so they need either to either locally disable irq around
876  * the read or for example on x86 they can be still implemented as a
877  * cmpxchg8b without the need of the lock prefix). For SMP compiles
878  * and 64bit archs it makes no difference if preempt is enabled or not.
879  */
880 static inline loff_t i_size_read(const struct inode *inode)
881 {
882 #if BITS_PER_LONG==32 && defined(CONFIG_SMP)
883 	loff_t i_size;
884 	unsigned int seq;
885 
886 	do {
887 		seq = read_seqcount_begin(&inode->i_size_seqcount);
888 		i_size = inode->i_size;
889 	} while (read_seqcount_retry(&inode->i_size_seqcount, seq));
890 	return i_size;
891 #elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPTION)
892 	loff_t i_size;
893 
894 	preempt_disable();
895 	i_size = inode->i_size;
896 	preempt_enable();
897 	return i_size;
898 #else
899 	/* Pairs with smp_store_release() in i_size_write() */
900 	return smp_load_acquire(&inode->i_size);
901 #endif
902 }
903 
904 /*
905  * NOTE: unlike i_size_read(), i_size_write() does need locking around it
906  * (normally i_mutex), otherwise on 32bit/SMP an update of i_size_seqcount
907  * can be lost, resulting in subsequent i_size_read() calls spinning forever.
908  */
909 static inline void i_size_write(struct inode *inode, loff_t i_size)
910 {
911 #if BITS_PER_LONG==32 && defined(CONFIG_SMP)
912 	preempt_disable();
913 	write_seqcount_begin(&inode->i_size_seqcount);
914 	inode->i_size = i_size;
915 	write_seqcount_end(&inode->i_size_seqcount);
916 	preempt_enable();
917 #elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPTION)
918 	preempt_disable();
919 	inode->i_size = i_size;
920 	preempt_enable();
921 #else
922 	/*
923 	 * Pairs with smp_load_acquire() in i_size_read() to ensure
924 	 * changes related to inode size (such as page contents) are
925 	 * visible before we see the changed inode size.
926 	 */
927 	smp_store_release(&inode->i_size, i_size);
928 #endif
929 }
930 
931 static inline unsigned iminor(const struct inode *inode)
932 {
933 	return MINOR(inode->i_rdev);
934 }
935 
936 static inline unsigned imajor(const struct inode *inode)
937 {
938 	return MAJOR(inode->i_rdev);
939 }
940 
941 struct fown_struct {
942 	rwlock_t lock;          /* protects pid, uid, euid fields */
943 	struct pid *pid;	/* pid or -pgrp where SIGIO should be sent */
944 	enum pid_type pid_type;	/* Kind of process group SIGIO should be sent to */
945 	kuid_t uid, euid;	/* uid/euid of process setting the owner */
946 	int signum;		/* posix.1b rt signal to be delivered on IO */
947 };
948 
949 /**
950  * struct file_ra_state - Track a file's readahead state.
951  * @start: Where the most recent readahead started.
952  * @size: Number of pages read in the most recent readahead.
953  * @async_size: Numer of pages that were/are not needed immediately
954  *      and so were/are genuinely "ahead".  Start next readahead when
955  *      the first of these pages is accessed.
956  * @ra_pages: Maximum size of a readahead request, copied from the bdi.
957  * @mmap_miss: How many mmap accesses missed in the page cache.
958  * @prev_pos: The last byte in the most recent read request.
959  *
960  * When this structure is passed to ->readahead(), the "most recent"
961  * readahead means the current readahead.
962  */
963 struct file_ra_state {
964 	pgoff_t start;
965 	unsigned int size;
966 	unsigned int async_size;
967 	unsigned int ra_pages;
968 	unsigned int mmap_miss;
969 	loff_t prev_pos;
970 };
971 
972 /*
973  * Check if @index falls in the readahead windows.
974  */
975 static inline int ra_has_index(struct file_ra_state *ra, pgoff_t index)
976 {
977 	return (index >= ra->start &&
978 		index <  ra->start + ra->size);
979 }
980 
981 /*
982  * f_{lock,count,pos_lock} members can be highly contended and share
983  * the same cacheline. f_{lock,mode} are very frequently used together
984  * and so share the same cacheline as well. The read-mostly
985  * f_{path,inode,op} are kept on a separate cacheline.
986  */
987 struct file {
988 	union {
989 		/* fput() uses task work when closing and freeing file (default). */
990 		struct callback_head 	f_task_work;
991 		/* fput() must use workqueue (most kernel threads). */
992 		struct llist_node	f_llist;
993 		unsigned int 		f_iocb_flags;
994 	};
995 
996 	/*
997 	 * Protects f_ep, f_flags.
998 	 * Must not be taken from IRQ context.
999 	 */
1000 	spinlock_t		f_lock;
1001 	fmode_t			f_mode;
1002 	atomic_long_t		f_count;
1003 	struct mutex		f_pos_lock;
1004 	loff_t			f_pos;
1005 	unsigned int		f_flags;
1006 	struct fown_struct	f_owner;
1007 	const struct cred	*f_cred;
1008 	struct file_ra_state	f_ra;
1009 	struct path		f_path;
1010 	struct inode		*f_inode;	/* cached value */
1011 	const struct file_operations	*f_op;
1012 
1013 	u64			f_version;
1014 #ifdef CONFIG_SECURITY
1015 	void			*f_security;
1016 #endif
1017 	/* needed for tty driver, and maybe others */
1018 	void			*private_data;
1019 
1020 #ifdef CONFIG_EPOLL
1021 	/* Used by fs/eventpoll.c to link all the hooks to this file */
1022 	struct hlist_head	*f_ep;
1023 #endif /* #ifdef CONFIG_EPOLL */
1024 	struct address_space	*f_mapping;
1025 	errseq_t		f_wb_err;
1026 	errseq_t		f_sb_err; /* for syncfs */
1027 } __randomize_layout
1028   __attribute__((aligned(4)));	/* lest something weird decides that 2 is OK */
1029 
1030 struct file_handle {
1031 	__u32 handle_bytes;
1032 	int handle_type;
1033 	/* file identifier */
1034 	unsigned char f_handle[] __counted_by(handle_bytes);
1035 };
1036 
1037 static inline struct file *get_file(struct file *f)
1038 {
1039 	long prior = atomic_long_fetch_inc_relaxed(&f->f_count);
1040 	WARN_ONCE(!prior, "struct file::f_count incremented from zero; use-after-free condition present!\n");
1041 	return f;
1042 }
1043 
1044 struct file *get_file_rcu(struct file __rcu **f);
1045 struct file *get_file_active(struct file **f);
1046 
1047 #define file_count(x)	atomic_long_read(&(x)->f_count)
1048 
1049 #define	MAX_NON_LFS	((1UL<<31) - 1)
1050 
1051 /* Page cache limit. The filesystems should put that into their s_maxbytes
1052    limits, otherwise bad things can happen in VM. */
1053 #if BITS_PER_LONG==32
1054 #define MAX_LFS_FILESIZE	((loff_t)ULONG_MAX << PAGE_SHIFT)
1055 #elif BITS_PER_LONG==64
1056 #define MAX_LFS_FILESIZE 	((loff_t)LLONG_MAX)
1057 #endif
1058 
1059 /* legacy typedef, should eventually be removed */
1060 typedef void *fl_owner_t;
1061 
1062 struct file_lock;
1063 struct file_lease;
1064 
1065 /* The following constant reflects the upper bound of the file/locking space */
1066 #ifndef OFFSET_MAX
1067 #define OFFSET_MAX	type_max(loff_t)
1068 #define OFFT_OFFSET_MAX	type_max(off_t)
1069 #endif
1070 
1071 extern void send_sigio(struct fown_struct *fown, int fd, int band);
1072 
1073 static inline struct inode *file_inode(const struct file *f)
1074 {
1075 	return f->f_inode;
1076 }
1077 
1078 /*
1079  * file_dentry() is a relic from the days that overlayfs was using files with a
1080  * "fake" path, meaning, f_path on overlayfs and f_inode on underlying fs.
1081  * In those days, file_dentry() was needed to get the underlying fs dentry that
1082  * matches f_inode.
1083  * Files with "fake" path should not exist nowadays, so use an assertion to make
1084  * sure that file_dentry() was not papering over filesystem bugs.
1085  */
1086 static inline struct dentry *file_dentry(const struct file *file)
1087 {
1088 	struct dentry *dentry = file->f_path.dentry;
1089 
1090 	WARN_ON_ONCE(d_inode(dentry) != file_inode(file));
1091 	return dentry;
1092 }
1093 
1094 struct fasync_struct {
1095 	rwlock_t		fa_lock;
1096 	int			magic;
1097 	int			fa_fd;
1098 	struct fasync_struct	*fa_next; /* singly linked list */
1099 	struct file		*fa_file;
1100 	struct rcu_head		fa_rcu;
1101 };
1102 
1103 #define FASYNC_MAGIC 0x4601
1104 
1105 /* SMP safe fasync helpers: */
1106 extern int fasync_helper(int, struct file *, int, struct fasync_struct **);
1107 extern struct fasync_struct *fasync_insert_entry(int, struct file *, struct fasync_struct **, struct fasync_struct *);
1108 extern int fasync_remove_entry(struct file *, struct fasync_struct **);
1109 extern struct fasync_struct *fasync_alloc(void);
1110 extern void fasync_free(struct fasync_struct *);
1111 
1112 /* can be called from interrupts */
1113 extern void kill_fasync(struct fasync_struct **, int, int);
1114 
1115 extern void __f_setown(struct file *filp, struct pid *, enum pid_type, int force);
1116 extern int f_setown(struct file *filp, int who, int force);
1117 extern void f_delown(struct file *filp);
1118 extern pid_t f_getown(struct file *filp);
1119 extern int send_sigurg(struct fown_struct *fown);
1120 
1121 /*
1122  * sb->s_flags.  Note that these mirror the equivalent MS_* flags where
1123  * represented in both.
1124  */
1125 #define SB_RDONLY       BIT(0)	/* Mount read-only */
1126 #define SB_NOSUID       BIT(1)	/* Ignore suid and sgid bits */
1127 #define SB_NODEV        BIT(2)	/* Disallow access to device special files */
1128 #define SB_NOEXEC       BIT(3)	/* Disallow program execution */
1129 #define SB_SYNCHRONOUS  BIT(4)	/* Writes are synced at once */
1130 #define SB_MANDLOCK     BIT(6)	/* Allow mandatory locks on an FS */
1131 #define SB_DIRSYNC      BIT(7)	/* Directory modifications are synchronous */
1132 #define SB_NOATIME      BIT(10)	/* Do not update access times. */
1133 #define SB_NODIRATIME   BIT(11)	/* Do not update directory access times */
1134 #define SB_SILENT       BIT(15)
1135 #define SB_POSIXACL     BIT(16)	/* Supports POSIX ACLs */
1136 #define SB_INLINECRYPT  BIT(17)	/* Use blk-crypto for encrypted files */
1137 #define SB_KERNMOUNT    BIT(22)	/* this is a kern_mount call */
1138 #define SB_I_VERSION    BIT(23)	/* Update inode I_version field */
1139 #define SB_LAZYTIME     BIT(25)	/* Update the on-disk [acm]times lazily */
1140 
1141 /* These sb flags are internal to the kernel */
1142 #define SB_DEAD         BIT(21)
1143 #define SB_DYING        BIT(24)
1144 #define SB_SUBMOUNT     BIT(26)
1145 #define SB_FORCE        BIT(27)
1146 #define SB_NOSEC        BIT(28)
1147 #define SB_BORN         BIT(29)
1148 #define SB_ACTIVE       BIT(30)
1149 #define SB_NOUSER       BIT(31)
1150 
1151 /* These flags relate to encoding and casefolding */
1152 #define SB_ENC_STRICT_MODE_FL	(1 << 0)
1153 
1154 #define sb_has_strict_encoding(sb) \
1155 	(sb->s_encoding_flags & SB_ENC_STRICT_MODE_FL)
1156 
1157 /*
1158  *	Umount options
1159  */
1160 
1161 #define MNT_FORCE	0x00000001	/* Attempt to forcibily umount */
1162 #define MNT_DETACH	0x00000002	/* Just detach from the tree */
1163 #define MNT_EXPIRE	0x00000004	/* Mark for expiry */
1164 #define UMOUNT_NOFOLLOW	0x00000008	/* Don't follow symlink on umount */
1165 #define UMOUNT_UNUSED	0x80000000	/* Flag guaranteed to be unused */
1166 
1167 /* sb->s_iflags */
1168 #define SB_I_CGROUPWB	0x00000001	/* cgroup-aware writeback enabled */
1169 #define SB_I_NOEXEC	0x00000002	/* Ignore executables on this fs */
1170 #define SB_I_NODEV	0x00000004	/* Ignore devices on this fs */
1171 #define SB_I_STABLE_WRITES 0x00000008	/* don't modify blks until WB is done */
1172 
1173 /* sb->s_iflags to limit user namespace mounts */
1174 #define SB_I_USERNS_VISIBLE		0x00000010 /* fstype already mounted */
1175 #define SB_I_IMA_UNVERIFIABLE_SIGNATURE	0x00000020
1176 #define SB_I_UNTRUSTED_MOUNTER		0x00000040
1177 #define SB_I_EVM_HMAC_UNSUPPORTED	0x00000080
1178 
1179 #define SB_I_SKIP_SYNC	0x00000100	/* Skip superblock at global sync */
1180 #define SB_I_PERSB_BDI	0x00000200	/* has a per-sb bdi */
1181 #define SB_I_TS_EXPIRY_WARNED 0x00000400 /* warned about timestamp range expiry */
1182 #define SB_I_RETIRED	0x00000800	/* superblock shouldn't be reused */
1183 #define SB_I_NOUMASK	0x00001000	/* VFS does not apply umask */
1184 
1185 /* Possible states of 'frozen' field */
1186 enum {
1187 	SB_UNFROZEN = 0,		/* FS is unfrozen */
1188 	SB_FREEZE_WRITE	= 1,		/* Writes, dir ops, ioctls frozen */
1189 	SB_FREEZE_PAGEFAULT = 2,	/* Page faults stopped as well */
1190 	SB_FREEZE_FS = 3,		/* For internal FS use (e.g. to stop
1191 					 * internal threads if needed) */
1192 	SB_FREEZE_COMPLETE = 4,		/* ->freeze_fs finished successfully */
1193 };
1194 
1195 #define SB_FREEZE_LEVELS (SB_FREEZE_COMPLETE - 1)
1196 
1197 struct sb_writers {
1198 	unsigned short			frozen;		/* Is sb frozen? */
1199 	int				freeze_kcount;	/* How many kernel freeze requests? */
1200 	int				freeze_ucount;	/* How many userspace freeze requests? */
1201 	struct percpu_rw_semaphore	rw_sem[SB_FREEZE_LEVELS];
1202 };
1203 
1204 struct super_block {
1205 	struct list_head	s_list;		/* Keep this first */
1206 	dev_t			s_dev;		/* search index; _not_ kdev_t */
1207 	unsigned char		s_blocksize_bits;
1208 	unsigned long		s_blocksize;
1209 	loff_t			s_maxbytes;	/* Max file size */
1210 	struct file_system_type	*s_type;
1211 	const struct super_operations	*s_op;
1212 	const struct dquot_operations	*dq_op;
1213 	const struct quotactl_ops	*s_qcop;
1214 	const struct export_operations *s_export_op;
1215 	unsigned long		s_flags;
1216 	unsigned long		s_iflags;	/* internal SB_I_* flags */
1217 	unsigned long		s_magic;
1218 	struct dentry		*s_root;
1219 	struct rw_semaphore	s_umount;
1220 	int			s_count;
1221 	atomic_t		s_active;
1222 #ifdef CONFIG_SECURITY
1223 	void                    *s_security;
1224 #endif
1225 	const struct xattr_handler * const *s_xattr;
1226 #ifdef CONFIG_FS_ENCRYPTION
1227 	const struct fscrypt_operations	*s_cop;
1228 	struct fscrypt_keyring	*s_master_keys; /* master crypto keys in use */
1229 #endif
1230 #ifdef CONFIG_FS_VERITY
1231 	const struct fsverity_operations *s_vop;
1232 #endif
1233 #if IS_ENABLED(CONFIG_UNICODE)
1234 	struct unicode_map *s_encoding;
1235 	__u16 s_encoding_flags;
1236 #endif
1237 	struct hlist_bl_head	s_roots;	/* alternate root dentries for NFS */
1238 	struct list_head	s_mounts;	/* list of mounts; _not_ for fs use */
1239 	struct block_device	*s_bdev;	/* can go away once we use an accessor for @s_bdev_file */
1240 	struct file		*s_bdev_file;
1241 	struct backing_dev_info *s_bdi;
1242 	struct mtd_info		*s_mtd;
1243 	struct hlist_node	s_instances;
1244 	unsigned int		s_quota_types;	/* Bitmask of supported quota types */
1245 	struct quota_info	s_dquot;	/* Diskquota specific options */
1246 
1247 	struct sb_writers	s_writers;
1248 
1249 	/*
1250 	 * Keep s_fs_info, s_time_gran, s_fsnotify_mask, and
1251 	 * s_fsnotify_info together for cache efficiency. They are frequently
1252 	 * accessed and rarely modified.
1253 	 */
1254 	void			*s_fs_info;	/* Filesystem private info */
1255 
1256 	/* Granularity of c/m/atime in ns (cannot be worse than a second) */
1257 	u32			s_time_gran;
1258 	/* Time limits for c/m/atime in seconds */
1259 	time64_t		   s_time_min;
1260 	time64_t		   s_time_max;
1261 #ifdef CONFIG_FSNOTIFY
1262 	__u32			s_fsnotify_mask;
1263 	struct fsnotify_sb_info	*s_fsnotify_info;
1264 #endif
1265 
1266 	/*
1267 	 * q: why are s_id and s_sysfs_name not the same? both are human
1268 	 * readable strings that identify the filesystem
1269 	 * a: s_id is allowed to change at runtime; it's used in log messages,
1270 	 * and we want to when a device starts out as single device (s_id is dev
1271 	 * name) but then a device is hot added and we have to switch to
1272 	 * identifying it by UUID
1273 	 * but s_sysfs_name is a handle for programmatic access, and can't
1274 	 * change at runtime
1275 	 */
1276 	char			s_id[32];	/* Informational name */
1277 	uuid_t			s_uuid;		/* UUID */
1278 	u8			s_uuid_len;	/* Default 16, possibly smaller for weird filesystems */
1279 
1280 	/* if set, fs shows up under sysfs at /sys/fs/$FSTYP/s_sysfs_name */
1281 	char			s_sysfs_name[UUID_STRING_LEN + 1];
1282 
1283 	unsigned int		s_max_links;
1284 
1285 	/*
1286 	 * The next field is for VFS *only*. No filesystems have any business
1287 	 * even looking at it. You had been warned.
1288 	 */
1289 	struct mutex s_vfs_rename_mutex;	/* Kludge */
1290 
1291 	/*
1292 	 * Filesystem subtype.  If non-empty the filesystem type field
1293 	 * in /proc/mounts will be "type.subtype"
1294 	 */
1295 	const char *s_subtype;
1296 
1297 	const struct dentry_operations *s_d_op; /* default d_op for dentries */
1298 
1299 	struct shrinker *s_shrink;	/* per-sb shrinker handle */
1300 
1301 	/* Number of inodes with nlink == 0 but still referenced */
1302 	atomic_long_t s_remove_count;
1303 
1304 	/* Read-only state of the superblock is being changed */
1305 	int s_readonly_remount;
1306 
1307 	/* per-sb errseq_t for reporting writeback errors via syncfs */
1308 	errseq_t s_wb_err;
1309 
1310 	/* AIO completions deferred from interrupt context */
1311 	struct workqueue_struct *s_dio_done_wq;
1312 	struct hlist_head s_pins;
1313 
1314 	/*
1315 	 * Owning user namespace and default context in which to
1316 	 * interpret filesystem uids, gids, quotas, device nodes,
1317 	 * xattrs and security labels.
1318 	 */
1319 	struct user_namespace *s_user_ns;
1320 
1321 	/*
1322 	 * The list_lru structure is essentially just a pointer to a table
1323 	 * of per-node lru lists, each of which has its own spinlock.
1324 	 * There is no need to put them into separate cachelines.
1325 	 */
1326 	struct list_lru		s_dentry_lru;
1327 	struct list_lru		s_inode_lru;
1328 	struct rcu_head		rcu;
1329 	struct work_struct	destroy_work;
1330 
1331 	struct mutex		s_sync_lock;	/* sync serialisation lock */
1332 
1333 	/*
1334 	 * Indicates how deep in a filesystem stack this SB is
1335 	 */
1336 	int s_stack_depth;
1337 
1338 	/* s_inode_list_lock protects s_inodes */
1339 	spinlock_t		s_inode_list_lock ____cacheline_aligned_in_smp;
1340 	struct list_head	s_inodes;	/* all inodes */
1341 
1342 	spinlock_t		s_inode_wblist_lock;
1343 	struct list_head	s_inodes_wb;	/* writeback inodes */
1344 } __randomize_layout;
1345 
1346 static inline struct user_namespace *i_user_ns(const struct inode *inode)
1347 {
1348 	return inode->i_sb->s_user_ns;
1349 }
1350 
1351 /* Helper functions so that in most cases filesystems will
1352  * not need to deal directly with kuid_t and kgid_t and can
1353  * instead deal with the raw numeric values that are stored
1354  * in the filesystem.
1355  */
1356 static inline uid_t i_uid_read(const struct inode *inode)
1357 {
1358 	return from_kuid(i_user_ns(inode), inode->i_uid);
1359 }
1360 
1361 static inline gid_t i_gid_read(const struct inode *inode)
1362 {
1363 	return from_kgid(i_user_ns(inode), inode->i_gid);
1364 }
1365 
1366 static inline void i_uid_write(struct inode *inode, uid_t uid)
1367 {
1368 	inode->i_uid = make_kuid(i_user_ns(inode), uid);
1369 }
1370 
1371 static inline void i_gid_write(struct inode *inode, gid_t gid)
1372 {
1373 	inode->i_gid = make_kgid(i_user_ns(inode), gid);
1374 }
1375 
1376 /**
1377  * i_uid_into_vfsuid - map an inode's i_uid down according to an idmapping
1378  * @idmap: idmap of the mount the inode was found from
1379  * @inode: inode to map
1380  *
1381  * Return: whe inode's i_uid mapped down according to @idmap.
1382  * If the inode's i_uid has no mapping INVALID_VFSUID is returned.
1383  */
1384 static inline vfsuid_t i_uid_into_vfsuid(struct mnt_idmap *idmap,
1385 					 const struct inode *inode)
1386 {
1387 	return make_vfsuid(idmap, i_user_ns(inode), inode->i_uid);
1388 }
1389 
1390 /**
1391  * i_uid_needs_update - check whether inode's i_uid needs to be updated
1392  * @idmap: idmap of the mount the inode was found from
1393  * @attr: the new attributes of @inode
1394  * @inode: the inode to update
1395  *
1396  * Check whether the $inode's i_uid field needs to be updated taking idmapped
1397  * mounts into account if the filesystem supports it.
1398  *
1399  * Return: true if @inode's i_uid field needs to be updated, false if not.
1400  */
1401 static inline bool i_uid_needs_update(struct mnt_idmap *idmap,
1402 				      const struct iattr *attr,
1403 				      const struct inode *inode)
1404 {
1405 	return ((attr->ia_valid & ATTR_UID) &&
1406 		!vfsuid_eq(attr->ia_vfsuid,
1407 			   i_uid_into_vfsuid(idmap, inode)));
1408 }
1409 
1410 /**
1411  * i_uid_update - update @inode's i_uid field
1412  * @idmap: idmap of the mount the inode was found from
1413  * @attr: the new attributes of @inode
1414  * @inode: the inode to update
1415  *
1416  * Safely update @inode's i_uid field translating the vfsuid of any idmapped
1417  * mount into the filesystem kuid.
1418  */
1419 static inline void i_uid_update(struct mnt_idmap *idmap,
1420 				const struct iattr *attr,
1421 				struct inode *inode)
1422 {
1423 	if (attr->ia_valid & ATTR_UID)
1424 		inode->i_uid = from_vfsuid(idmap, i_user_ns(inode),
1425 					   attr->ia_vfsuid);
1426 }
1427 
1428 /**
1429  * i_gid_into_vfsgid - map an inode's i_gid down according to an idmapping
1430  * @idmap: idmap of the mount the inode was found from
1431  * @inode: inode to map
1432  *
1433  * Return: the inode's i_gid mapped down according to @idmap.
1434  * If the inode's i_gid has no mapping INVALID_VFSGID is returned.
1435  */
1436 static inline vfsgid_t i_gid_into_vfsgid(struct mnt_idmap *idmap,
1437 					 const struct inode *inode)
1438 {
1439 	return make_vfsgid(idmap, i_user_ns(inode), inode->i_gid);
1440 }
1441 
1442 /**
1443  * i_gid_needs_update - check whether inode's i_gid needs to be updated
1444  * @idmap: idmap of the mount the inode was found from
1445  * @attr: the new attributes of @inode
1446  * @inode: the inode to update
1447  *
1448  * Check whether the $inode's i_gid field needs to be updated taking idmapped
1449  * mounts into account if the filesystem supports it.
1450  *
1451  * Return: true if @inode's i_gid field needs to be updated, false if not.
1452  */
1453 static inline bool i_gid_needs_update(struct mnt_idmap *idmap,
1454 				      const struct iattr *attr,
1455 				      const struct inode *inode)
1456 {
1457 	return ((attr->ia_valid & ATTR_GID) &&
1458 		!vfsgid_eq(attr->ia_vfsgid,
1459 			   i_gid_into_vfsgid(idmap, inode)));
1460 }
1461 
1462 /**
1463  * i_gid_update - update @inode's i_gid field
1464  * @idmap: idmap of the mount the inode was found from
1465  * @attr: the new attributes of @inode
1466  * @inode: the inode to update
1467  *
1468  * Safely update @inode's i_gid field translating the vfsgid of any idmapped
1469  * mount into the filesystem kgid.
1470  */
1471 static inline void i_gid_update(struct mnt_idmap *idmap,
1472 				const struct iattr *attr,
1473 				struct inode *inode)
1474 {
1475 	if (attr->ia_valid & ATTR_GID)
1476 		inode->i_gid = from_vfsgid(idmap, i_user_ns(inode),
1477 					   attr->ia_vfsgid);
1478 }
1479 
1480 /**
1481  * inode_fsuid_set - initialize inode's i_uid field with callers fsuid
1482  * @inode: inode to initialize
1483  * @idmap: idmap of the mount the inode was found from
1484  *
1485  * Initialize the i_uid field of @inode. If the inode was found/created via
1486  * an idmapped mount map the caller's fsuid according to @idmap.
1487  */
1488 static inline void inode_fsuid_set(struct inode *inode,
1489 				   struct mnt_idmap *idmap)
1490 {
1491 	inode->i_uid = mapped_fsuid(idmap, i_user_ns(inode));
1492 }
1493 
1494 /**
1495  * inode_fsgid_set - initialize inode's i_gid field with callers fsgid
1496  * @inode: inode to initialize
1497  * @idmap: idmap of the mount the inode was found from
1498  *
1499  * Initialize the i_gid field of @inode. If the inode was found/created via
1500  * an idmapped mount map the caller's fsgid according to @idmap.
1501  */
1502 static inline void inode_fsgid_set(struct inode *inode,
1503 				   struct mnt_idmap *idmap)
1504 {
1505 	inode->i_gid = mapped_fsgid(idmap, i_user_ns(inode));
1506 }
1507 
1508 /**
1509  * fsuidgid_has_mapping() - check whether caller's fsuid/fsgid is mapped
1510  * @sb: the superblock we want a mapping in
1511  * @idmap: idmap of the relevant mount
1512  *
1513  * Check whether the caller's fsuid and fsgid have a valid mapping in the
1514  * s_user_ns of the superblock @sb. If the caller is on an idmapped mount map
1515  * the caller's fsuid and fsgid according to the @idmap first.
1516  *
1517  * Return: true if fsuid and fsgid is mapped, false if not.
1518  */
1519 static inline bool fsuidgid_has_mapping(struct super_block *sb,
1520 					struct mnt_idmap *idmap)
1521 {
1522 	struct user_namespace *fs_userns = sb->s_user_ns;
1523 	kuid_t kuid;
1524 	kgid_t kgid;
1525 
1526 	kuid = mapped_fsuid(idmap, fs_userns);
1527 	if (!uid_valid(kuid))
1528 		return false;
1529 	kgid = mapped_fsgid(idmap, fs_userns);
1530 	if (!gid_valid(kgid))
1531 		return false;
1532 	return kuid_has_mapping(fs_userns, kuid) &&
1533 	       kgid_has_mapping(fs_userns, kgid);
1534 }
1535 
1536 struct timespec64 current_time(struct inode *inode);
1537 struct timespec64 inode_set_ctime_current(struct inode *inode);
1538 
1539 static inline time64_t inode_get_atime_sec(const struct inode *inode)
1540 {
1541 	return inode->__i_atime.tv_sec;
1542 }
1543 
1544 static inline long inode_get_atime_nsec(const struct inode *inode)
1545 {
1546 	return inode->__i_atime.tv_nsec;
1547 }
1548 
1549 static inline struct timespec64 inode_get_atime(const struct inode *inode)
1550 {
1551 	return inode->__i_atime;
1552 }
1553 
1554 static inline struct timespec64 inode_set_atime_to_ts(struct inode *inode,
1555 						      struct timespec64 ts)
1556 {
1557 	inode->__i_atime = ts;
1558 	return ts;
1559 }
1560 
1561 static inline struct timespec64 inode_set_atime(struct inode *inode,
1562 						time64_t sec, long nsec)
1563 {
1564 	struct timespec64 ts = { .tv_sec  = sec,
1565 				 .tv_nsec = nsec };
1566 	return inode_set_atime_to_ts(inode, ts);
1567 }
1568 
1569 static inline time64_t inode_get_mtime_sec(const struct inode *inode)
1570 {
1571 	return inode->__i_mtime.tv_sec;
1572 }
1573 
1574 static inline long inode_get_mtime_nsec(const struct inode *inode)
1575 {
1576 	return inode->__i_mtime.tv_nsec;
1577 }
1578 
1579 static inline struct timespec64 inode_get_mtime(const struct inode *inode)
1580 {
1581 	return inode->__i_mtime;
1582 }
1583 
1584 static inline struct timespec64 inode_set_mtime_to_ts(struct inode *inode,
1585 						      struct timespec64 ts)
1586 {
1587 	inode->__i_mtime = ts;
1588 	return ts;
1589 }
1590 
1591 static inline struct timespec64 inode_set_mtime(struct inode *inode,
1592 						time64_t sec, long nsec)
1593 {
1594 	struct timespec64 ts = { .tv_sec  = sec,
1595 				 .tv_nsec = nsec };
1596 	return inode_set_mtime_to_ts(inode, ts);
1597 }
1598 
1599 static inline time64_t inode_get_ctime_sec(const struct inode *inode)
1600 {
1601 	return inode->__i_ctime.tv_sec;
1602 }
1603 
1604 static inline long inode_get_ctime_nsec(const struct inode *inode)
1605 {
1606 	return inode->__i_ctime.tv_nsec;
1607 }
1608 
1609 static inline struct timespec64 inode_get_ctime(const struct inode *inode)
1610 {
1611 	return inode->__i_ctime;
1612 }
1613 
1614 static inline struct timespec64 inode_set_ctime_to_ts(struct inode *inode,
1615 						      struct timespec64 ts)
1616 {
1617 	inode->__i_ctime = ts;
1618 	return ts;
1619 }
1620 
1621 /**
1622  * inode_set_ctime - set the ctime in the inode
1623  * @inode: inode in which to set the ctime
1624  * @sec: tv_sec value to set
1625  * @nsec: tv_nsec value to set
1626  *
1627  * Set the ctime in @inode to { @sec, @nsec }
1628  */
1629 static inline struct timespec64 inode_set_ctime(struct inode *inode,
1630 						time64_t sec, long nsec)
1631 {
1632 	struct timespec64 ts = { .tv_sec  = sec,
1633 				 .tv_nsec = nsec };
1634 
1635 	return inode_set_ctime_to_ts(inode, ts);
1636 }
1637 
1638 struct timespec64 simple_inode_init_ts(struct inode *inode);
1639 
1640 /*
1641  * Snapshotting support.
1642  */
1643 
1644 /*
1645  * These are internal functions, please use sb_start_{write,pagefault,intwrite}
1646  * instead.
1647  */
1648 static inline void __sb_end_write(struct super_block *sb, int level)
1649 {
1650 	percpu_up_read(sb->s_writers.rw_sem + level-1);
1651 }
1652 
1653 static inline void __sb_start_write(struct super_block *sb, int level)
1654 {
1655 	percpu_down_read(sb->s_writers.rw_sem + level - 1);
1656 }
1657 
1658 static inline bool __sb_start_write_trylock(struct super_block *sb, int level)
1659 {
1660 	return percpu_down_read_trylock(sb->s_writers.rw_sem + level - 1);
1661 }
1662 
1663 #define __sb_writers_acquired(sb, lev)	\
1664 	percpu_rwsem_acquire(&(sb)->s_writers.rw_sem[(lev)-1], 1, _THIS_IP_)
1665 #define __sb_writers_release(sb, lev)	\
1666 	percpu_rwsem_release(&(sb)->s_writers.rw_sem[(lev)-1], 1, _THIS_IP_)
1667 
1668 /**
1669  * __sb_write_started - check if sb freeze level is held
1670  * @sb: the super we write to
1671  * @level: the freeze level
1672  *
1673  * * > 0 - sb freeze level is held
1674  * *   0 - sb freeze level is not held
1675  * * < 0 - !CONFIG_LOCKDEP/LOCK_STATE_UNKNOWN
1676  */
1677 static inline int __sb_write_started(const struct super_block *sb, int level)
1678 {
1679 	return lockdep_is_held_type(sb->s_writers.rw_sem + level - 1, 1);
1680 }
1681 
1682 /**
1683  * sb_write_started - check if SB_FREEZE_WRITE is held
1684  * @sb: the super we write to
1685  *
1686  * May be false positive with !CONFIG_LOCKDEP/LOCK_STATE_UNKNOWN.
1687  */
1688 static inline bool sb_write_started(const struct super_block *sb)
1689 {
1690 	return __sb_write_started(sb, SB_FREEZE_WRITE);
1691 }
1692 
1693 /**
1694  * sb_write_not_started - check if SB_FREEZE_WRITE is not held
1695  * @sb: the super we write to
1696  *
1697  * May be false positive with !CONFIG_LOCKDEP/LOCK_STATE_UNKNOWN.
1698  */
1699 static inline bool sb_write_not_started(const struct super_block *sb)
1700 {
1701 	return __sb_write_started(sb, SB_FREEZE_WRITE) <= 0;
1702 }
1703 
1704 /**
1705  * file_write_started - check if SB_FREEZE_WRITE is held
1706  * @file: the file we write to
1707  *
1708  * May be false positive with !CONFIG_LOCKDEP/LOCK_STATE_UNKNOWN.
1709  * May be false positive with !S_ISREG, because file_start_write() has
1710  * no effect on !S_ISREG.
1711  */
1712 static inline bool file_write_started(const struct file *file)
1713 {
1714 	if (!S_ISREG(file_inode(file)->i_mode))
1715 		return true;
1716 	return sb_write_started(file_inode(file)->i_sb);
1717 }
1718 
1719 /**
1720  * file_write_not_started - check if SB_FREEZE_WRITE is not held
1721  * @file: the file we write to
1722  *
1723  * May be false positive with !CONFIG_LOCKDEP/LOCK_STATE_UNKNOWN.
1724  * May be false positive with !S_ISREG, because file_start_write() has
1725  * no effect on !S_ISREG.
1726  */
1727 static inline bool file_write_not_started(const struct file *file)
1728 {
1729 	if (!S_ISREG(file_inode(file)->i_mode))
1730 		return true;
1731 	return sb_write_not_started(file_inode(file)->i_sb);
1732 }
1733 
1734 /**
1735  * sb_end_write - drop write access to a superblock
1736  * @sb: the super we wrote to
1737  *
1738  * Decrement number of writers to the filesystem. Wake up possible waiters
1739  * wanting to freeze the filesystem.
1740  */
1741 static inline void sb_end_write(struct super_block *sb)
1742 {
1743 	__sb_end_write(sb, SB_FREEZE_WRITE);
1744 }
1745 
1746 /**
1747  * sb_end_pagefault - drop write access to a superblock from a page fault
1748  * @sb: the super we wrote to
1749  *
1750  * Decrement number of processes handling write page fault to the filesystem.
1751  * Wake up possible waiters wanting to freeze the filesystem.
1752  */
1753 static inline void sb_end_pagefault(struct super_block *sb)
1754 {
1755 	__sb_end_write(sb, SB_FREEZE_PAGEFAULT);
1756 }
1757 
1758 /**
1759  * sb_end_intwrite - drop write access to a superblock for internal fs purposes
1760  * @sb: the super we wrote to
1761  *
1762  * Decrement fs-internal number of writers to the filesystem.  Wake up possible
1763  * waiters wanting to freeze the filesystem.
1764  */
1765 static inline void sb_end_intwrite(struct super_block *sb)
1766 {
1767 	__sb_end_write(sb, SB_FREEZE_FS);
1768 }
1769 
1770 /**
1771  * sb_start_write - get write access to a superblock
1772  * @sb: the super we write to
1773  *
1774  * When a process wants to write data or metadata to a file system (i.e. dirty
1775  * a page or an inode), it should embed the operation in a sb_start_write() -
1776  * sb_end_write() pair to get exclusion against file system freezing. This
1777  * function increments number of writers preventing freezing. If the file
1778  * system is already frozen, the function waits until the file system is
1779  * thawed.
1780  *
1781  * Since freeze protection behaves as a lock, users have to preserve
1782  * ordering of freeze protection and other filesystem locks. Generally,
1783  * freeze protection should be the outermost lock. In particular, we have:
1784  *
1785  * sb_start_write
1786  *   -> i_mutex			(write path, truncate, directory ops, ...)
1787  *   -> s_umount		(freeze_super, thaw_super)
1788  */
1789 static inline void sb_start_write(struct super_block *sb)
1790 {
1791 	__sb_start_write(sb, SB_FREEZE_WRITE);
1792 }
1793 
1794 static inline bool sb_start_write_trylock(struct super_block *sb)
1795 {
1796 	return __sb_start_write_trylock(sb, SB_FREEZE_WRITE);
1797 }
1798 
1799 /**
1800  * sb_start_pagefault - get write access to a superblock from a page fault
1801  * @sb: the super we write to
1802  *
1803  * When a process starts handling write page fault, it should embed the
1804  * operation into sb_start_pagefault() - sb_end_pagefault() pair to get
1805  * exclusion against file system freezing. This is needed since the page fault
1806  * is going to dirty a page. This function increments number of running page
1807  * faults preventing freezing. If the file system is already frozen, the
1808  * function waits until the file system is thawed.
1809  *
1810  * Since page fault freeze protection behaves as a lock, users have to preserve
1811  * ordering of freeze protection and other filesystem locks. It is advised to
1812  * put sb_start_pagefault() close to mmap_lock in lock ordering. Page fault
1813  * handling code implies lock dependency:
1814  *
1815  * mmap_lock
1816  *   -> sb_start_pagefault
1817  */
1818 static inline void sb_start_pagefault(struct super_block *sb)
1819 {
1820 	__sb_start_write(sb, SB_FREEZE_PAGEFAULT);
1821 }
1822 
1823 /**
1824  * sb_start_intwrite - get write access to a superblock for internal fs purposes
1825  * @sb: the super we write to
1826  *
1827  * This is the third level of protection against filesystem freezing. It is
1828  * free for use by a filesystem. The only requirement is that it must rank
1829  * below sb_start_pagefault.
1830  *
1831  * For example filesystem can call sb_start_intwrite() when starting a
1832  * transaction which somewhat eases handling of freezing for internal sources
1833  * of filesystem changes (internal fs threads, discarding preallocation on file
1834  * close, etc.).
1835  */
1836 static inline void sb_start_intwrite(struct super_block *sb)
1837 {
1838 	__sb_start_write(sb, SB_FREEZE_FS);
1839 }
1840 
1841 static inline bool sb_start_intwrite_trylock(struct super_block *sb)
1842 {
1843 	return __sb_start_write_trylock(sb, SB_FREEZE_FS);
1844 }
1845 
1846 bool inode_owner_or_capable(struct mnt_idmap *idmap,
1847 			    const struct inode *inode);
1848 
1849 /*
1850  * VFS helper functions..
1851  */
1852 int vfs_create(struct mnt_idmap *, struct inode *,
1853 	       struct dentry *, umode_t, bool);
1854 int vfs_mkdir(struct mnt_idmap *, struct inode *,
1855 	      struct dentry *, umode_t);
1856 int vfs_mknod(struct mnt_idmap *, struct inode *, struct dentry *,
1857               umode_t, dev_t);
1858 int vfs_symlink(struct mnt_idmap *, struct inode *,
1859 		struct dentry *, const char *);
1860 int vfs_link(struct dentry *, struct mnt_idmap *, struct inode *,
1861 	     struct dentry *, struct inode **);
1862 int vfs_rmdir(struct mnt_idmap *, struct inode *, struct dentry *);
1863 int vfs_unlink(struct mnt_idmap *, struct inode *, struct dentry *,
1864 	       struct inode **);
1865 
1866 /**
1867  * struct renamedata - contains all information required for renaming
1868  * @old_mnt_idmap:     idmap of the old mount the inode was found from
1869  * @old_dir:           parent of source
1870  * @old_dentry:                source
1871  * @new_mnt_idmap:     idmap of the new mount the inode was found from
1872  * @new_dir:           parent of destination
1873  * @new_dentry:                destination
1874  * @delegated_inode:   returns an inode needing a delegation break
1875  * @flags:             rename flags
1876  */
1877 struct renamedata {
1878 	struct mnt_idmap *old_mnt_idmap;
1879 	struct inode *old_dir;
1880 	struct dentry *old_dentry;
1881 	struct mnt_idmap *new_mnt_idmap;
1882 	struct inode *new_dir;
1883 	struct dentry *new_dentry;
1884 	struct inode **delegated_inode;
1885 	unsigned int flags;
1886 } __randomize_layout;
1887 
1888 int vfs_rename(struct renamedata *);
1889 
1890 static inline int vfs_whiteout(struct mnt_idmap *idmap,
1891 			       struct inode *dir, struct dentry *dentry)
1892 {
1893 	return vfs_mknod(idmap, dir, dentry, S_IFCHR | WHITEOUT_MODE,
1894 			 WHITEOUT_DEV);
1895 }
1896 
1897 struct file *kernel_tmpfile_open(struct mnt_idmap *idmap,
1898 				 const struct path *parentpath,
1899 				 umode_t mode, int open_flag,
1900 				 const struct cred *cred);
1901 struct file *kernel_file_open(const struct path *path, int flags,
1902 			      const struct cred *cred);
1903 
1904 int vfs_mkobj(struct dentry *, umode_t,
1905 		int (*f)(struct dentry *, umode_t, void *),
1906 		void *);
1907 
1908 int vfs_fchown(struct file *file, uid_t user, gid_t group);
1909 int vfs_fchmod(struct file *file, umode_t mode);
1910 int vfs_utimes(const struct path *path, struct timespec64 *times);
1911 
1912 extern long vfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
1913 
1914 #ifdef CONFIG_COMPAT
1915 extern long compat_ptr_ioctl(struct file *file, unsigned int cmd,
1916 					unsigned long arg);
1917 #else
1918 #define compat_ptr_ioctl NULL
1919 #endif
1920 
1921 /*
1922  * VFS file helper functions.
1923  */
1924 void inode_init_owner(struct mnt_idmap *idmap, struct inode *inode,
1925 		      const struct inode *dir, umode_t mode);
1926 extern bool may_open_dev(const struct path *path);
1927 umode_t mode_strip_sgid(struct mnt_idmap *idmap,
1928 			const struct inode *dir, umode_t mode);
1929 
1930 /*
1931  * This is the "filldir" function type, used by readdir() to let
1932  * the kernel specify what kind of dirent layout it wants to have.
1933  * This allows the kernel to read directories into kernel space or
1934  * to have different dirent layouts depending on the binary type.
1935  * Return 'true' to keep going and 'false' if there are no more entries.
1936  */
1937 struct dir_context;
1938 typedef bool (*filldir_t)(struct dir_context *, const char *, int, loff_t, u64,
1939 			 unsigned);
1940 
1941 struct dir_context {
1942 	filldir_t actor;
1943 	loff_t pos;
1944 };
1945 
1946 /*
1947  * These flags let !MMU mmap() govern direct device mapping vs immediate
1948  * copying more easily for MAP_PRIVATE, especially for ROM filesystems.
1949  *
1950  * NOMMU_MAP_COPY:	Copy can be mapped (MAP_PRIVATE)
1951  * NOMMU_MAP_DIRECT:	Can be mapped directly (MAP_SHARED)
1952  * NOMMU_MAP_READ:	Can be mapped for reading
1953  * NOMMU_MAP_WRITE:	Can be mapped for writing
1954  * NOMMU_MAP_EXEC:	Can be mapped for execution
1955  */
1956 #define NOMMU_MAP_COPY		0x00000001
1957 #define NOMMU_MAP_DIRECT	0x00000008
1958 #define NOMMU_MAP_READ		VM_MAYREAD
1959 #define NOMMU_MAP_WRITE		VM_MAYWRITE
1960 #define NOMMU_MAP_EXEC		VM_MAYEXEC
1961 
1962 #define NOMMU_VMFLAGS \
1963 	(NOMMU_MAP_READ | NOMMU_MAP_WRITE | NOMMU_MAP_EXEC)
1964 
1965 /*
1966  * These flags control the behavior of the remap_file_range function pointer.
1967  * If it is called with len == 0 that means "remap to end of source file".
1968  * See Documentation/filesystems/vfs.rst for more details about this call.
1969  *
1970  * REMAP_FILE_DEDUP: only remap if contents identical (i.e. deduplicate)
1971  * REMAP_FILE_CAN_SHORTEN: caller can handle a shortened request
1972  */
1973 #define REMAP_FILE_DEDUP		(1 << 0)
1974 #define REMAP_FILE_CAN_SHORTEN		(1 << 1)
1975 
1976 /*
1977  * These flags signal that the caller is ok with altering various aspects of
1978  * the behavior of the remap operation.  The changes must be made by the
1979  * implementation; the vfs remap helper functions can take advantage of them.
1980  * Flags in this category exist to preserve the quirky behavior of the hoisted
1981  * btrfs clone/dedupe ioctls.
1982  */
1983 #define REMAP_FILE_ADVISORY		(REMAP_FILE_CAN_SHORTEN)
1984 
1985 /*
1986  * These flags control the behavior of vfs_copy_file_range().
1987  * They are not available to the user via syscall.
1988  *
1989  * COPY_FILE_SPLICE: call splice direct instead of fs clone/copy ops
1990  */
1991 #define COPY_FILE_SPLICE		(1 << 0)
1992 
1993 struct iov_iter;
1994 struct io_uring_cmd;
1995 struct offset_ctx;
1996 
1997 typedef unsigned int __bitwise fop_flags_t;
1998 
1999 struct file_operations {
2000 	struct module *owner;
2001 	fop_flags_t fop_flags;
2002 	loff_t (*llseek) (struct file *, loff_t, int);
2003 	ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);
2004 	ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
2005 	ssize_t (*read_iter) (struct kiocb *, struct iov_iter *);
2006 	ssize_t (*write_iter) (struct kiocb *, struct iov_iter *);
2007 	int (*iopoll)(struct kiocb *kiocb, struct io_comp_batch *,
2008 			unsigned int flags);
2009 	int (*iterate_shared) (struct file *, struct dir_context *);
2010 	__poll_t (*poll) (struct file *, struct poll_table_struct *);
2011 	long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
2012 	long (*compat_ioctl) (struct file *, unsigned int, unsigned long);
2013 	int (*mmap) (struct file *, struct vm_area_struct *);
2014 	int (*open) (struct inode *, struct file *);
2015 	int (*flush) (struct file *, fl_owner_t id);
2016 	int (*release) (struct inode *, struct file *);
2017 	int (*fsync) (struct file *, loff_t, loff_t, int datasync);
2018 	int (*fasync) (int, struct file *, int);
2019 	int (*lock) (struct file *, int, struct file_lock *);
2020 	unsigned long (*get_unmapped_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
2021 	int (*check_flags)(int);
2022 	int (*flock) (struct file *, int, struct file_lock *);
2023 	ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, loff_t *, size_t, unsigned int);
2024 	ssize_t (*splice_read)(struct file *, loff_t *, struct pipe_inode_info *, size_t, unsigned int);
2025 	void (*splice_eof)(struct file *file);
2026 	int (*setlease)(struct file *, int, struct file_lease **, void **);
2027 	long (*fallocate)(struct file *file, int mode, loff_t offset,
2028 			  loff_t len);
2029 	void (*show_fdinfo)(struct seq_file *m, struct file *f);
2030 #ifndef CONFIG_MMU
2031 	unsigned (*mmap_capabilities)(struct file *);
2032 #endif
2033 	ssize_t (*copy_file_range)(struct file *, loff_t, struct file *,
2034 			loff_t, size_t, unsigned int);
2035 	loff_t (*remap_file_range)(struct file *file_in, loff_t pos_in,
2036 				   struct file *file_out, loff_t pos_out,
2037 				   loff_t len, unsigned int remap_flags);
2038 	int (*fadvise)(struct file *, loff_t, loff_t, int);
2039 	int (*uring_cmd)(struct io_uring_cmd *ioucmd, unsigned int issue_flags);
2040 	int (*uring_cmd_iopoll)(struct io_uring_cmd *, struct io_comp_batch *,
2041 				unsigned int poll_flags);
2042 } __randomize_layout;
2043 
2044 /* Supports async buffered reads */
2045 #define FOP_BUFFER_RASYNC	((__force fop_flags_t)(1 << 0))
2046 /* Supports async buffered writes */
2047 #define FOP_BUFFER_WASYNC	((__force fop_flags_t)(1 << 1))
2048 /* Supports synchronous page faults for mappings */
2049 #define FOP_MMAP_SYNC		((__force fop_flags_t)(1 << 2))
2050 /* Supports non-exclusive O_DIRECT writes from multiple threads */
2051 #define FOP_DIO_PARALLEL_WRITE	((__force fop_flags_t)(1 << 3))
2052 /* Contains huge pages */
2053 #define FOP_HUGE_PAGES		((__force fop_flags_t)(1 << 4))
2054 
2055 /* Wrap a directory iterator that needs exclusive inode access */
2056 int wrap_directory_iterator(struct file *, struct dir_context *,
2057 			    int (*) (struct file *, struct dir_context *));
2058 #define WRAP_DIR_ITER(x) \
2059 	static int shared_##x(struct file *file , struct dir_context *ctx) \
2060 	{ return wrap_directory_iterator(file, ctx, x); }
2061 
2062 struct inode_operations {
2063 	struct dentry * (*lookup) (struct inode *,struct dentry *, unsigned int);
2064 	const char * (*get_link) (struct dentry *, struct inode *, struct delayed_call *);
2065 	int (*permission) (struct mnt_idmap *, struct inode *, int);
2066 	struct posix_acl * (*get_inode_acl)(struct inode *, int, bool);
2067 
2068 	int (*readlink) (struct dentry *, char __user *,int);
2069 
2070 	int (*create) (struct mnt_idmap *, struct inode *,struct dentry *,
2071 		       umode_t, bool);
2072 	int (*link) (struct dentry *,struct inode *,struct dentry *);
2073 	int (*unlink) (struct inode *,struct dentry *);
2074 	int (*symlink) (struct mnt_idmap *, struct inode *,struct dentry *,
2075 			const char *);
2076 	int (*mkdir) (struct mnt_idmap *, struct inode *,struct dentry *,
2077 		      umode_t);
2078 	int (*rmdir) (struct inode *,struct dentry *);
2079 	int (*mknod) (struct mnt_idmap *, struct inode *,struct dentry *,
2080 		      umode_t,dev_t);
2081 	int (*rename) (struct mnt_idmap *, struct inode *, struct dentry *,
2082 			struct inode *, struct dentry *, unsigned int);
2083 	int (*setattr) (struct mnt_idmap *, struct dentry *, struct iattr *);
2084 	int (*getattr) (struct mnt_idmap *, const struct path *,
2085 			struct kstat *, u32, unsigned int);
2086 	ssize_t (*listxattr) (struct dentry *, char *, size_t);
2087 	int (*fiemap)(struct inode *, struct fiemap_extent_info *, u64 start,
2088 		      u64 len);
2089 	int (*update_time)(struct inode *, int);
2090 	int (*atomic_open)(struct inode *, struct dentry *,
2091 			   struct file *, unsigned open_flag,
2092 			   umode_t create_mode);
2093 	int (*tmpfile) (struct mnt_idmap *, struct inode *,
2094 			struct file *, umode_t);
2095 	struct posix_acl *(*get_acl)(struct mnt_idmap *, struct dentry *,
2096 				     int);
2097 	int (*set_acl)(struct mnt_idmap *, struct dentry *,
2098 		       struct posix_acl *, int);
2099 	int (*fileattr_set)(struct mnt_idmap *idmap,
2100 			    struct dentry *dentry, struct fileattr *fa);
2101 	int (*fileattr_get)(struct dentry *dentry, struct fileattr *fa);
2102 	struct offset_ctx *(*get_offset_ctx)(struct inode *inode);
2103 } ____cacheline_aligned;
2104 
2105 static inline int call_mmap(struct file *file, struct vm_area_struct *vma)
2106 {
2107 	return file->f_op->mmap(file, vma);
2108 }
2109 
2110 extern ssize_t vfs_read(struct file *, char __user *, size_t, loff_t *);
2111 extern ssize_t vfs_write(struct file *, const char __user *, size_t, loff_t *);
2112 extern ssize_t vfs_copy_file_range(struct file *, loff_t , struct file *,
2113 				   loff_t, size_t, unsigned int);
2114 int remap_verify_area(struct file *file, loff_t pos, loff_t len, bool write);
2115 int __generic_remap_file_range_prep(struct file *file_in, loff_t pos_in,
2116 				    struct file *file_out, loff_t pos_out,
2117 				    loff_t *len, unsigned int remap_flags,
2118 				    const struct iomap_ops *dax_read_ops);
2119 int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in,
2120 				  struct file *file_out, loff_t pos_out,
2121 				  loff_t *count, unsigned int remap_flags);
2122 extern loff_t vfs_clone_file_range(struct file *file_in, loff_t pos_in,
2123 				   struct file *file_out, loff_t pos_out,
2124 				   loff_t len, unsigned int remap_flags);
2125 extern int vfs_dedupe_file_range(struct file *file,
2126 				 struct file_dedupe_range *same);
2127 extern loff_t vfs_dedupe_file_range_one(struct file *src_file, loff_t src_pos,
2128 					struct file *dst_file, loff_t dst_pos,
2129 					loff_t len, unsigned int remap_flags);
2130 
2131 /**
2132  * enum freeze_holder - holder of the freeze
2133  * @FREEZE_HOLDER_KERNEL: kernel wants to freeze or thaw filesystem
2134  * @FREEZE_HOLDER_USERSPACE: userspace wants to freeze or thaw filesystem
2135  * @FREEZE_MAY_NEST: whether nesting freeze and thaw requests is allowed
2136  *
2137  * Indicate who the owner of the freeze or thaw request is and whether
2138  * the freeze needs to be exclusive or can nest.
2139  * Without @FREEZE_MAY_NEST, multiple freeze and thaw requests from the
2140  * same holder aren't allowed. It is however allowed to hold a single
2141  * @FREEZE_HOLDER_USERSPACE and a single @FREEZE_HOLDER_KERNEL freeze at
2142  * the same time. This is relied upon by some filesystems during online
2143  * repair or similar.
2144  */
2145 enum freeze_holder {
2146 	FREEZE_HOLDER_KERNEL	= (1U << 0),
2147 	FREEZE_HOLDER_USERSPACE	= (1U << 1),
2148 	FREEZE_MAY_NEST		= (1U << 2),
2149 };
2150 
2151 struct super_operations {
2152    	struct inode *(*alloc_inode)(struct super_block *sb);
2153 	void (*destroy_inode)(struct inode *);
2154 	void (*free_inode)(struct inode *);
2155 
2156    	void (*dirty_inode) (struct inode *, int flags);
2157 	int (*write_inode) (struct inode *, struct writeback_control *wbc);
2158 	int (*drop_inode) (struct inode *);
2159 	void (*evict_inode) (struct inode *);
2160 	void (*put_super) (struct super_block *);
2161 	int (*sync_fs)(struct super_block *sb, int wait);
2162 	int (*freeze_super) (struct super_block *, enum freeze_holder who);
2163 	int (*freeze_fs) (struct super_block *);
2164 	int (*thaw_super) (struct super_block *, enum freeze_holder who);
2165 	int (*unfreeze_fs) (struct super_block *);
2166 	int (*statfs) (struct dentry *, struct kstatfs *);
2167 	int (*remount_fs) (struct super_block *, int *, char *);
2168 	void (*umount_begin) (struct super_block *);
2169 
2170 	int (*show_options)(struct seq_file *, struct dentry *);
2171 	int (*show_devname)(struct seq_file *, struct dentry *);
2172 	int (*show_path)(struct seq_file *, struct dentry *);
2173 	int (*show_stats)(struct seq_file *, struct dentry *);
2174 #ifdef CONFIG_QUOTA
2175 	ssize_t (*quota_read)(struct super_block *, int, char *, size_t, loff_t);
2176 	ssize_t (*quota_write)(struct super_block *, int, const char *, size_t, loff_t);
2177 	struct dquot __rcu **(*get_dquots)(struct inode *);
2178 #endif
2179 	long (*nr_cached_objects)(struct super_block *,
2180 				  struct shrink_control *);
2181 	long (*free_cached_objects)(struct super_block *,
2182 				    struct shrink_control *);
2183 	void (*shutdown)(struct super_block *sb);
2184 };
2185 
2186 /*
2187  * Inode flags - they have no relation to superblock flags now
2188  */
2189 #define S_SYNC		(1 << 0)  /* Writes are synced at once */
2190 #define S_NOATIME	(1 << 1)  /* Do not update access times */
2191 #define S_APPEND	(1 << 2)  /* Append-only file */
2192 #define S_IMMUTABLE	(1 << 3)  /* Immutable file */
2193 #define S_DEAD		(1 << 4)  /* removed, but still open directory */
2194 #define S_NOQUOTA	(1 << 5)  /* Inode is not counted to quota */
2195 #define S_DIRSYNC	(1 << 6)  /* Directory modifications are synchronous */
2196 #define S_NOCMTIME	(1 << 7)  /* Do not update file c/mtime */
2197 #define S_SWAPFILE	(1 << 8)  /* Do not truncate: swapon got its bmaps */
2198 #define S_PRIVATE	(1 << 9)  /* Inode is fs-internal */
2199 #define S_IMA		(1 << 10) /* Inode has an associated IMA struct */
2200 #define S_AUTOMOUNT	(1 << 11) /* Automount/referral quasi-directory */
2201 #define S_NOSEC		(1 << 12) /* no suid or xattr security attributes */
2202 #ifdef CONFIG_FS_DAX
2203 #define S_DAX		(1 << 13) /* Direct Access, avoiding the page cache */
2204 #else
2205 #define S_DAX		0	  /* Make all the DAX code disappear */
2206 #endif
2207 #define S_ENCRYPTED	(1 << 14) /* Encrypted file (using fs/crypto/) */
2208 #define S_CASEFOLD	(1 << 15) /* Casefolded file */
2209 #define S_VERITY	(1 << 16) /* Verity file (using fs/verity/) */
2210 #define S_KERNEL_FILE	(1 << 17) /* File is in use by the kernel (eg. fs/cachefiles) */
2211 
2212 /*
2213  * Note that nosuid etc flags are inode-specific: setting some file-system
2214  * flags just means all the inodes inherit those flags by default. It might be
2215  * possible to override it selectively if you really wanted to with some
2216  * ioctl() that is not currently implemented.
2217  *
2218  * Exception: SB_RDONLY is always applied to the entire file system.
2219  *
2220  * Unfortunately, it is possible to change a filesystems flags with it mounted
2221  * with files in use.  This means that all of the inodes will not have their
2222  * i_flags updated.  Hence, i_flags no longer inherit the superblock mount
2223  * flags, so these have to be checked separately. -- rmk@arm.uk.linux.org
2224  */
2225 #define __IS_FLG(inode, flg)	((inode)->i_sb->s_flags & (flg))
2226 
2227 static inline bool sb_rdonly(const struct super_block *sb) { return sb->s_flags & SB_RDONLY; }
2228 #define IS_RDONLY(inode)	sb_rdonly((inode)->i_sb)
2229 #define IS_SYNC(inode)		(__IS_FLG(inode, SB_SYNCHRONOUS) || \
2230 					((inode)->i_flags & S_SYNC))
2231 #define IS_DIRSYNC(inode)	(__IS_FLG(inode, SB_SYNCHRONOUS|SB_DIRSYNC) || \
2232 					((inode)->i_flags & (S_SYNC|S_DIRSYNC)))
2233 #define IS_MANDLOCK(inode)	__IS_FLG(inode, SB_MANDLOCK)
2234 #define IS_NOATIME(inode)	__IS_FLG(inode, SB_RDONLY|SB_NOATIME)
2235 #define IS_I_VERSION(inode)	__IS_FLG(inode, SB_I_VERSION)
2236 
2237 #define IS_NOQUOTA(inode)	((inode)->i_flags & S_NOQUOTA)
2238 #define IS_APPEND(inode)	((inode)->i_flags & S_APPEND)
2239 #define IS_IMMUTABLE(inode)	((inode)->i_flags & S_IMMUTABLE)
2240 
2241 #ifdef CONFIG_FS_POSIX_ACL
2242 #define IS_POSIXACL(inode)	__IS_FLG(inode, SB_POSIXACL)
2243 #else
2244 #define IS_POSIXACL(inode)	0
2245 #endif
2246 
2247 #define IS_DEADDIR(inode)	((inode)->i_flags & S_DEAD)
2248 #define IS_NOCMTIME(inode)	((inode)->i_flags & S_NOCMTIME)
2249 
2250 #ifdef CONFIG_SWAP
2251 #define IS_SWAPFILE(inode)	((inode)->i_flags & S_SWAPFILE)
2252 #else
2253 #define IS_SWAPFILE(inode)	((void)(inode), 0U)
2254 #endif
2255 
2256 #define IS_PRIVATE(inode)	((inode)->i_flags & S_PRIVATE)
2257 #define IS_IMA(inode)		((inode)->i_flags & S_IMA)
2258 #define IS_AUTOMOUNT(inode)	((inode)->i_flags & S_AUTOMOUNT)
2259 #define IS_NOSEC(inode)		((inode)->i_flags & S_NOSEC)
2260 #define IS_DAX(inode)		((inode)->i_flags & S_DAX)
2261 #define IS_ENCRYPTED(inode)	((inode)->i_flags & S_ENCRYPTED)
2262 #define IS_CASEFOLDED(inode)	((inode)->i_flags & S_CASEFOLD)
2263 #define IS_VERITY(inode)	((inode)->i_flags & S_VERITY)
2264 
2265 #define IS_WHITEOUT(inode)	(S_ISCHR(inode->i_mode) && \
2266 				 (inode)->i_rdev == WHITEOUT_DEV)
2267 
2268 static inline bool HAS_UNMAPPED_ID(struct mnt_idmap *idmap,
2269 				   struct inode *inode)
2270 {
2271 	return !vfsuid_valid(i_uid_into_vfsuid(idmap, inode)) ||
2272 	       !vfsgid_valid(i_gid_into_vfsgid(idmap, inode));
2273 }
2274 
2275 static inline void init_sync_kiocb(struct kiocb *kiocb, struct file *filp)
2276 {
2277 	*kiocb = (struct kiocb) {
2278 		.ki_filp = filp,
2279 		.ki_flags = filp->f_iocb_flags,
2280 		.ki_ioprio = get_current_ioprio(),
2281 	};
2282 }
2283 
2284 static inline void kiocb_clone(struct kiocb *kiocb, struct kiocb *kiocb_src,
2285 			       struct file *filp)
2286 {
2287 	*kiocb = (struct kiocb) {
2288 		.ki_filp = filp,
2289 		.ki_flags = kiocb_src->ki_flags,
2290 		.ki_ioprio = kiocb_src->ki_ioprio,
2291 		.ki_pos = kiocb_src->ki_pos,
2292 	};
2293 }
2294 
2295 /*
2296  * Inode state bits.  Protected by inode->i_lock
2297  *
2298  * Four bits determine the dirty state of the inode: I_DIRTY_SYNC,
2299  * I_DIRTY_DATASYNC, I_DIRTY_PAGES, and I_DIRTY_TIME.
2300  *
2301  * Four bits define the lifetime of an inode.  Initially, inodes are I_NEW,
2302  * until that flag is cleared.  I_WILL_FREE, I_FREEING and I_CLEAR are set at
2303  * various stages of removing an inode.
2304  *
2305  * Two bits are used for locking and completion notification, I_NEW and I_SYNC.
2306  *
2307  * I_DIRTY_SYNC		Inode is dirty, but doesn't have to be written on
2308  *			fdatasync() (unless I_DIRTY_DATASYNC is also set).
2309  *			Timestamp updates are the usual cause.
2310  * I_DIRTY_DATASYNC	Data-related inode changes pending.  We keep track of
2311  *			these changes separately from I_DIRTY_SYNC so that we
2312  *			don't have to write inode on fdatasync() when only
2313  *			e.g. the timestamps have changed.
2314  * I_DIRTY_PAGES	Inode has dirty pages.  Inode itself may be clean.
2315  * I_DIRTY_TIME		The inode itself has dirty timestamps, and the
2316  *			lazytime mount option is enabled.  We keep track of this
2317  *			separately from I_DIRTY_SYNC in order to implement
2318  *			lazytime.  This gets cleared if I_DIRTY_INODE
2319  *			(I_DIRTY_SYNC and/or I_DIRTY_DATASYNC) gets set. But
2320  *			I_DIRTY_TIME can still be set if I_DIRTY_SYNC is already
2321  *			in place because writeback might already be in progress
2322  *			and we don't want to lose the time update
2323  * I_NEW		Serves as both a mutex and completion notification.
2324  *			New inodes set I_NEW.  If two processes both create
2325  *			the same inode, one of them will release its inode and
2326  *			wait for I_NEW to be released before returning.
2327  *			Inodes in I_WILL_FREE, I_FREEING or I_CLEAR state can
2328  *			also cause waiting on I_NEW, without I_NEW actually
2329  *			being set.  find_inode() uses this to prevent returning
2330  *			nearly-dead inodes.
2331  * I_WILL_FREE		Must be set when calling write_inode_now() if i_count
2332  *			is zero.  I_FREEING must be set when I_WILL_FREE is
2333  *			cleared.
2334  * I_FREEING		Set when inode is about to be freed but still has dirty
2335  *			pages or buffers attached or the inode itself is still
2336  *			dirty.
2337  * I_CLEAR		Added by clear_inode().  In this state the inode is
2338  *			clean and can be destroyed.  Inode keeps I_FREEING.
2339  *
2340  *			Inodes that are I_WILL_FREE, I_FREEING or I_CLEAR are
2341  *			prohibited for many purposes.  iget() must wait for
2342  *			the inode to be completely released, then create it
2343  *			anew.  Other functions will just ignore such inodes,
2344  *			if appropriate.  I_NEW is used for waiting.
2345  *
2346  * I_SYNC		Writeback of inode is running. The bit is set during
2347  *			data writeback, and cleared with a wakeup on the bit
2348  *			address once it is done. The bit is also used to pin
2349  *			the inode in memory for flusher thread.
2350  *
2351  * I_REFERENCED		Marks the inode as recently references on the LRU list.
2352  *
2353  * I_DIO_WAKEUP		Never set.  Only used as a key for wait_on_bit().
2354  *
2355  * I_WB_SWITCH		Cgroup bdi_writeback switching in progress.  Used to
2356  *			synchronize competing switching instances and to tell
2357  *			wb stat updates to grab the i_pages lock.  See
2358  *			inode_switch_wbs_work_fn() for details.
2359  *
2360  * I_OVL_INUSE		Used by overlayfs to get exclusive ownership on upper
2361  *			and work dirs among overlayfs mounts.
2362  *
2363  * I_CREATING		New object's inode in the middle of setting up.
2364  *
2365  * I_DONTCACHE		Evict inode as soon as it is not used anymore.
2366  *
2367  * I_SYNC_QUEUED	Inode is queued in b_io or b_more_io writeback lists.
2368  *			Used to detect that mark_inode_dirty() should not move
2369  * 			inode between dirty lists.
2370  *
2371  * I_PINNING_FSCACHE_WB	Inode is pinning an fscache object for writeback.
2372  *
2373  * Q: What is the difference between I_WILL_FREE and I_FREEING?
2374  */
2375 #define I_DIRTY_SYNC		(1 << 0)
2376 #define I_DIRTY_DATASYNC	(1 << 1)
2377 #define I_DIRTY_PAGES		(1 << 2)
2378 #define __I_NEW			3
2379 #define I_NEW			(1 << __I_NEW)
2380 #define I_WILL_FREE		(1 << 4)
2381 #define I_FREEING		(1 << 5)
2382 #define I_CLEAR			(1 << 6)
2383 #define __I_SYNC		7
2384 #define I_SYNC			(1 << __I_SYNC)
2385 #define I_REFERENCED		(1 << 8)
2386 #define __I_DIO_WAKEUP		9
2387 #define I_DIO_WAKEUP		(1 << __I_DIO_WAKEUP)
2388 #define I_LINKABLE		(1 << 10)
2389 #define I_DIRTY_TIME		(1 << 11)
2390 #define I_WB_SWITCH		(1 << 13)
2391 #define I_OVL_INUSE		(1 << 14)
2392 #define I_CREATING		(1 << 15)
2393 #define I_DONTCACHE		(1 << 16)
2394 #define I_SYNC_QUEUED		(1 << 17)
2395 #define I_PINNING_NETFS_WB	(1 << 18)
2396 
2397 #define I_DIRTY_INODE (I_DIRTY_SYNC | I_DIRTY_DATASYNC)
2398 #define I_DIRTY (I_DIRTY_INODE | I_DIRTY_PAGES)
2399 #define I_DIRTY_ALL (I_DIRTY | I_DIRTY_TIME)
2400 
2401 extern void __mark_inode_dirty(struct inode *, int);
2402 static inline void mark_inode_dirty(struct inode *inode)
2403 {
2404 	__mark_inode_dirty(inode, I_DIRTY);
2405 }
2406 
2407 static inline void mark_inode_dirty_sync(struct inode *inode)
2408 {
2409 	__mark_inode_dirty(inode, I_DIRTY_SYNC);
2410 }
2411 
2412 /*
2413  * Returns true if the given inode itself only has dirty timestamps (its pages
2414  * may still be dirty) and isn't currently being allocated or freed.
2415  * Filesystems should call this if when writing an inode when lazytime is
2416  * enabled, they want to opportunistically write the timestamps of other inodes
2417  * located very nearby on-disk, e.g. in the same inode block.  This returns true
2418  * if the given inode is in need of such an opportunistic update.  Requires
2419  * i_lock, or at least later re-checking under i_lock.
2420  */
2421 static inline bool inode_is_dirtytime_only(struct inode *inode)
2422 {
2423 	return (inode->i_state & (I_DIRTY_TIME | I_NEW |
2424 				  I_FREEING | I_WILL_FREE)) == I_DIRTY_TIME;
2425 }
2426 
2427 extern void inc_nlink(struct inode *inode);
2428 extern void drop_nlink(struct inode *inode);
2429 extern void clear_nlink(struct inode *inode);
2430 extern void set_nlink(struct inode *inode, unsigned int nlink);
2431 
2432 static inline void inode_inc_link_count(struct inode *inode)
2433 {
2434 	inc_nlink(inode);
2435 	mark_inode_dirty(inode);
2436 }
2437 
2438 static inline void inode_dec_link_count(struct inode *inode)
2439 {
2440 	drop_nlink(inode);
2441 	mark_inode_dirty(inode);
2442 }
2443 
2444 enum file_time_flags {
2445 	S_ATIME = 1,
2446 	S_MTIME = 2,
2447 	S_CTIME = 4,
2448 	S_VERSION = 8,
2449 };
2450 
2451 extern bool atime_needs_update(const struct path *, struct inode *);
2452 extern void touch_atime(const struct path *);
2453 int inode_update_time(struct inode *inode, int flags);
2454 
2455 static inline void file_accessed(struct file *file)
2456 {
2457 	if (!(file->f_flags & O_NOATIME))
2458 		touch_atime(&file->f_path);
2459 }
2460 
2461 extern int file_modified(struct file *file);
2462 int kiocb_modified(struct kiocb *iocb);
2463 
2464 int sync_inode_metadata(struct inode *inode, int wait);
2465 
2466 struct file_system_type {
2467 	const char *name;
2468 	int fs_flags;
2469 #define FS_REQUIRES_DEV		1
2470 #define FS_BINARY_MOUNTDATA	2
2471 #define FS_HAS_SUBTYPE		4
2472 #define FS_USERNS_MOUNT		8	/* Can be mounted by userns root */
2473 #define FS_DISALLOW_NOTIFY_PERM	16	/* Disable fanotify permission events */
2474 #define FS_ALLOW_IDMAP         32      /* FS has been updated to handle vfs idmappings. */
2475 #define FS_RENAME_DOES_D_MOVE	32768	/* FS will handle d_move() during rename() internally. */
2476 	int (*init_fs_context)(struct fs_context *);
2477 	const struct fs_parameter_spec *parameters;
2478 	struct dentry *(*mount) (struct file_system_type *, int,
2479 		       const char *, void *);
2480 	void (*kill_sb) (struct super_block *);
2481 	struct module *owner;
2482 	struct file_system_type * next;
2483 	struct hlist_head fs_supers;
2484 
2485 	struct lock_class_key s_lock_key;
2486 	struct lock_class_key s_umount_key;
2487 	struct lock_class_key s_vfs_rename_key;
2488 	struct lock_class_key s_writers_key[SB_FREEZE_LEVELS];
2489 
2490 	struct lock_class_key i_lock_key;
2491 	struct lock_class_key i_mutex_key;
2492 	struct lock_class_key invalidate_lock_key;
2493 	struct lock_class_key i_mutex_dir_key;
2494 };
2495 
2496 #define MODULE_ALIAS_FS(NAME) MODULE_ALIAS("fs-" NAME)
2497 
2498 extern struct dentry *mount_bdev(struct file_system_type *fs_type,
2499 	int flags, const char *dev_name, void *data,
2500 	int (*fill_super)(struct super_block *, void *, int));
2501 extern struct dentry *mount_single(struct file_system_type *fs_type,
2502 	int flags, void *data,
2503 	int (*fill_super)(struct super_block *, void *, int));
2504 extern struct dentry *mount_nodev(struct file_system_type *fs_type,
2505 	int flags, void *data,
2506 	int (*fill_super)(struct super_block *, void *, int));
2507 extern struct dentry *mount_subtree(struct vfsmount *mnt, const char *path);
2508 void retire_super(struct super_block *sb);
2509 void generic_shutdown_super(struct super_block *sb);
2510 void kill_block_super(struct super_block *sb);
2511 void kill_anon_super(struct super_block *sb);
2512 void kill_litter_super(struct super_block *sb);
2513 void deactivate_super(struct super_block *sb);
2514 void deactivate_locked_super(struct super_block *sb);
2515 int set_anon_super(struct super_block *s, void *data);
2516 int set_anon_super_fc(struct super_block *s, struct fs_context *fc);
2517 int get_anon_bdev(dev_t *);
2518 void free_anon_bdev(dev_t);
2519 struct super_block *sget_fc(struct fs_context *fc,
2520 			    int (*test)(struct super_block *, struct fs_context *),
2521 			    int (*set)(struct super_block *, struct fs_context *));
2522 struct super_block *sget(struct file_system_type *type,
2523 			int (*test)(struct super_block *,void *),
2524 			int (*set)(struct super_block *,void *),
2525 			int flags, void *data);
2526 struct super_block *sget_dev(struct fs_context *fc, dev_t dev);
2527 
2528 /* Alas, no aliases. Too much hassle with bringing module.h everywhere */
2529 #define fops_get(fops) \
2530 	(((fops) && try_module_get((fops)->owner) ? (fops) : NULL))
2531 #define fops_put(fops) \
2532 	do { if (fops) module_put((fops)->owner); } while(0)
2533 /*
2534  * This one is to be used *ONLY* from ->open() instances.
2535  * fops must be non-NULL, pinned down *and* module dependencies
2536  * should be sufficient to pin the caller down as well.
2537  */
2538 #define replace_fops(f, fops) \
2539 	do {	\
2540 		struct file *__file = (f); \
2541 		fops_put(__file->f_op); \
2542 		BUG_ON(!(__file->f_op = (fops))); \
2543 	} while(0)
2544 
2545 extern int register_filesystem(struct file_system_type *);
2546 extern int unregister_filesystem(struct file_system_type *);
2547 extern int vfs_statfs(const struct path *, struct kstatfs *);
2548 extern int user_statfs(const char __user *, struct kstatfs *);
2549 extern int fd_statfs(int, struct kstatfs *);
2550 int freeze_super(struct super_block *super, enum freeze_holder who);
2551 int thaw_super(struct super_block *super, enum freeze_holder who);
2552 extern __printf(2, 3)
2553 int super_setup_bdi_name(struct super_block *sb, char *fmt, ...);
2554 extern int super_setup_bdi(struct super_block *sb);
2555 
2556 static inline void super_set_uuid(struct super_block *sb, const u8 *uuid, unsigned len)
2557 {
2558 	if (WARN_ON(len > sizeof(sb->s_uuid)))
2559 		len = sizeof(sb->s_uuid);
2560 	sb->s_uuid_len = len;
2561 	memcpy(&sb->s_uuid, uuid, len);
2562 }
2563 
2564 /* set sb sysfs name based on sb->s_bdev */
2565 static inline void super_set_sysfs_name_bdev(struct super_block *sb)
2566 {
2567 	snprintf(sb->s_sysfs_name, sizeof(sb->s_sysfs_name), "%pg", sb->s_bdev);
2568 }
2569 
2570 /* set sb sysfs name based on sb->s_uuid */
2571 static inline void super_set_sysfs_name_uuid(struct super_block *sb)
2572 {
2573 	WARN_ON(sb->s_uuid_len != sizeof(sb->s_uuid));
2574 	snprintf(sb->s_sysfs_name, sizeof(sb->s_sysfs_name), "%pU", sb->s_uuid.b);
2575 }
2576 
2577 /* set sb sysfs name based on sb->s_id */
2578 static inline void super_set_sysfs_name_id(struct super_block *sb)
2579 {
2580 	strscpy(sb->s_sysfs_name, sb->s_id, sizeof(sb->s_sysfs_name));
2581 }
2582 
2583 /* try to use something standard before you use this */
2584 __printf(2, 3)
2585 static inline void super_set_sysfs_name_generic(struct super_block *sb, const char *fmt, ...)
2586 {
2587 	va_list args;
2588 
2589 	va_start(args, fmt);
2590 	vsnprintf(sb->s_sysfs_name, sizeof(sb->s_sysfs_name), fmt, args);
2591 	va_end(args);
2592 }
2593 
2594 extern int current_umask(void);
2595 
2596 extern void ihold(struct inode * inode);
2597 extern void iput(struct inode *);
2598 int inode_update_timestamps(struct inode *inode, int flags);
2599 int generic_update_time(struct inode *, int);
2600 
2601 /* /sys/fs */
2602 extern struct kobject *fs_kobj;
2603 
2604 #define MAX_RW_COUNT (INT_MAX & PAGE_MASK)
2605 
2606 /* fs/open.c */
2607 struct audit_names;
2608 struct filename {
2609 	const char		*name;	/* pointer to actual string */
2610 	const __user char	*uptr;	/* original userland pointer */
2611 	atomic_t		refcnt;
2612 	struct audit_names	*aname;
2613 	const char		iname[];
2614 };
2615 static_assert(offsetof(struct filename, iname) % sizeof(long) == 0);
2616 
2617 static inline struct mnt_idmap *file_mnt_idmap(const struct file *file)
2618 {
2619 	return mnt_idmap(file->f_path.mnt);
2620 }
2621 
2622 /**
2623  * is_idmapped_mnt - check whether a mount is mapped
2624  * @mnt: the mount to check
2625  *
2626  * If @mnt has an non @nop_mnt_idmap attached to it then @mnt is mapped.
2627  *
2628  * Return: true if mount is mapped, false if not.
2629  */
2630 static inline bool is_idmapped_mnt(const struct vfsmount *mnt)
2631 {
2632 	return mnt_idmap(mnt) != &nop_mnt_idmap;
2633 }
2634 
2635 extern long vfs_truncate(const struct path *, loff_t);
2636 int do_truncate(struct mnt_idmap *, struct dentry *, loff_t start,
2637 		unsigned int time_attrs, struct file *filp);
2638 extern int vfs_fallocate(struct file *file, int mode, loff_t offset,
2639 			loff_t len);
2640 extern long do_sys_open(int dfd, const char __user *filename, int flags,
2641 			umode_t mode);
2642 extern struct file *file_open_name(struct filename *, int, umode_t);
2643 extern struct file *filp_open(const char *, int, umode_t);
2644 extern struct file *file_open_root(const struct path *,
2645 				   const char *, int, umode_t);
2646 static inline struct file *file_open_root_mnt(struct vfsmount *mnt,
2647 				   const char *name, int flags, umode_t mode)
2648 {
2649 	return file_open_root(&(struct path){.mnt = mnt, .dentry = mnt->mnt_root},
2650 			      name, flags, mode);
2651 }
2652 struct file *dentry_open(const struct path *path, int flags,
2653 			 const struct cred *creds);
2654 struct file *dentry_create(const struct path *path, int flags, umode_t mode,
2655 			   const struct cred *cred);
2656 struct path *backing_file_user_path(struct file *f);
2657 
2658 /*
2659  * When mmapping a file on a stackable filesystem (e.g., overlayfs), the file
2660  * stored in ->vm_file is a backing file whose f_inode is on the underlying
2661  * filesystem.  When the mapped file path and inode number are displayed to
2662  * user (e.g. via /proc/<pid>/maps), these helpers should be used to get the
2663  * path and inode number to display to the user, which is the path of the fd
2664  * that user has requested to map and the inode number that would be returned
2665  * by fstat() on that same fd.
2666  */
2667 /* Get the path to display in /proc/<pid>/maps */
2668 static inline const struct path *file_user_path(struct file *f)
2669 {
2670 	if (unlikely(f->f_mode & FMODE_BACKING))
2671 		return backing_file_user_path(f);
2672 	return &f->f_path;
2673 }
2674 /* Get the inode whose inode number to display in /proc/<pid>/maps */
2675 static inline const struct inode *file_user_inode(struct file *f)
2676 {
2677 	if (unlikely(f->f_mode & FMODE_BACKING))
2678 		return d_inode(backing_file_user_path(f)->dentry);
2679 	return file_inode(f);
2680 }
2681 
2682 static inline struct file *file_clone_open(struct file *file)
2683 {
2684 	return dentry_open(&file->f_path, file->f_flags, file->f_cred);
2685 }
2686 extern int filp_close(struct file *, fl_owner_t id);
2687 
2688 extern struct filename *getname_flags(const char __user *, int, int *);
2689 extern struct filename *getname_uflags(const char __user *, int);
2690 extern struct filename *getname(const char __user *);
2691 extern struct filename *getname_kernel(const char *);
2692 extern void putname(struct filename *name);
2693 
2694 extern int finish_open(struct file *file, struct dentry *dentry,
2695 			int (*open)(struct inode *, struct file *));
2696 extern int finish_no_open(struct file *file, struct dentry *dentry);
2697 
2698 /* Helper for the simple case when original dentry is used */
2699 static inline int finish_open_simple(struct file *file, int error)
2700 {
2701 	if (error)
2702 		return error;
2703 
2704 	return finish_open(file, file->f_path.dentry, NULL);
2705 }
2706 
2707 /* fs/dcache.c */
2708 extern void __init vfs_caches_init_early(void);
2709 extern void __init vfs_caches_init(void);
2710 
2711 extern struct kmem_cache *names_cachep;
2712 
2713 #define __getname()		kmem_cache_alloc(names_cachep, GFP_KERNEL)
2714 #define __putname(name)		kmem_cache_free(names_cachep, (void *)(name))
2715 
2716 extern struct super_block *blockdev_superblock;
2717 static inline bool sb_is_blkdev_sb(struct super_block *sb)
2718 {
2719 	return IS_ENABLED(CONFIG_BLOCK) && sb == blockdev_superblock;
2720 }
2721 
2722 void emergency_thaw_all(void);
2723 extern int sync_filesystem(struct super_block *);
2724 extern const struct file_operations def_blk_fops;
2725 extern const struct file_operations def_chr_fops;
2726 
2727 /* fs/char_dev.c */
2728 #define CHRDEV_MAJOR_MAX 512
2729 /* Marks the bottom of the first segment of free char majors */
2730 #define CHRDEV_MAJOR_DYN_END 234
2731 /* Marks the top and bottom of the second segment of free char majors */
2732 #define CHRDEV_MAJOR_DYN_EXT_START 511
2733 #define CHRDEV_MAJOR_DYN_EXT_END 384
2734 
2735 extern int alloc_chrdev_region(dev_t *, unsigned, unsigned, const char *);
2736 extern int register_chrdev_region(dev_t, unsigned, const char *);
2737 extern int __register_chrdev(unsigned int major, unsigned int baseminor,
2738 			     unsigned int count, const char *name,
2739 			     const struct file_operations *fops);
2740 extern void __unregister_chrdev(unsigned int major, unsigned int baseminor,
2741 				unsigned int count, const char *name);
2742 extern void unregister_chrdev_region(dev_t, unsigned);
2743 extern void chrdev_show(struct seq_file *,off_t);
2744 
2745 static inline int register_chrdev(unsigned int major, const char *name,
2746 				  const struct file_operations *fops)
2747 {
2748 	return __register_chrdev(major, 0, 256, name, fops);
2749 }
2750 
2751 static inline void unregister_chrdev(unsigned int major, const char *name)
2752 {
2753 	__unregister_chrdev(major, 0, 256, name);
2754 }
2755 
2756 extern void init_special_inode(struct inode *, umode_t, dev_t);
2757 
2758 /* Invalid inode operations -- fs/bad_inode.c */
2759 extern void make_bad_inode(struct inode *);
2760 extern bool is_bad_inode(struct inode *);
2761 
2762 extern int __must_check file_fdatawait_range(struct file *file, loff_t lstart,
2763 						loff_t lend);
2764 extern int __must_check file_check_and_advance_wb_err(struct file *file);
2765 extern int __must_check file_write_and_wait_range(struct file *file,
2766 						loff_t start, loff_t end);
2767 
2768 static inline int file_write_and_wait(struct file *file)
2769 {
2770 	return file_write_and_wait_range(file, 0, LLONG_MAX);
2771 }
2772 
2773 extern int vfs_fsync_range(struct file *file, loff_t start, loff_t end,
2774 			   int datasync);
2775 extern int vfs_fsync(struct file *file, int datasync);
2776 
2777 extern int sync_file_range(struct file *file, loff_t offset, loff_t nbytes,
2778 				unsigned int flags);
2779 
2780 static inline bool iocb_is_dsync(const struct kiocb *iocb)
2781 {
2782 	return (iocb->ki_flags & IOCB_DSYNC) ||
2783 		IS_SYNC(iocb->ki_filp->f_mapping->host);
2784 }
2785 
2786 /*
2787  * Sync the bytes written if this was a synchronous write.  Expect ki_pos
2788  * to already be updated for the write, and will return either the amount
2789  * of bytes passed in, or an error if syncing the file failed.
2790  */
2791 static inline ssize_t generic_write_sync(struct kiocb *iocb, ssize_t count)
2792 {
2793 	if (iocb_is_dsync(iocb)) {
2794 		int ret = vfs_fsync_range(iocb->ki_filp,
2795 				iocb->ki_pos - count, iocb->ki_pos - 1,
2796 				(iocb->ki_flags & IOCB_SYNC) ? 0 : 1);
2797 		if (ret)
2798 			return ret;
2799 	}
2800 
2801 	return count;
2802 }
2803 
2804 extern void emergency_sync(void);
2805 extern void emergency_remount(void);
2806 
2807 #ifdef CONFIG_BLOCK
2808 extern int bmap(struct inode *inode, sector_t *block);
2809 #else
2810 static inline int bmap(struct inode *inode,  sector_t *block)
2811 {
2812 	return -EINVAL;
2813 }
2814 #endif
2815 
2816 int notify_change(struct mnt_idmap *, struct dentry *,
2817 		  struct iattr *, struct inode **);
2818 int inode_permission(struct mnt_idmap *, struct inode *, int);
2819 int generic_permission(struct mnt_idmap *, struct inode *, int);
2820 static inline int file_permission(struct file *file, int mask)
2821 {
2822 	return inode_permission(file_mnt_idmap(file),
2823 				file_inode(file), mask);
2824 }
2825 static inline int path_permission(const struct path *path, int mask)
2826 {
2827 	return inode_permission(mnt_idmap(path->mnt),
2828 				d_inode(path->dentry), mask);
2829 }
2830 int __check_sticky(struct mnt_idmap *idmap, struct inode *dir,
2831 		   struct inode *inode);
2832 
2833 static inline bool execute_ok(struct inode *inode)
2834 {
2835 	return (inode->i_mode & S_IXUGO) || S_ISDIR(inode->i_mode);
2836 }
2837 
2838 static inline bool inode_wrong_type(const struct inode *inode, umode_t mode)
2839 {
2840 	return (inode->i_mode ^ mode) & S_IFMT;
2841 }
2842 
2843 /**
2844  * file_start_write - get write access to a superblock for regular file io
2845  * @file: the file we want to write to
2846  *
2847  * This is a variant of sb_start_write() which is a noop on non-regualr file.
2848  * Should be matched with a call to file_end_write().
2849  */
2850 static inline void file_start_write(struct file *file)
2851 {
2852 	if (!S_ISREG(file_inode(file)->i_mode))
2853 		return;
2854 	sb_start_write(file_inode(file)->i_sb);
2855 }
2856 
2857 static inline bool file_start_write_trylock(struct file *file)
2858 {
2859 	if (!S_ISREG(file_inode(file)->i_mode))
2860 		return true;
2861 	return sb_start_write_trylock(file_inode(file)->i_sb);
2862 }
2863 
2864 /**
2865  * file_end_write - drop write access to a superblock of a regular file
2866  * @file: the file we wrote to
2867  *
2868  * Should be matched with a call to file_start_write().
2869  */
2870 static inline void file_end_write(struct file *file)
2871 {
2872 	if (!S_ISREG(file_inode(file)->i_mode))
2873 		return;
2874 	sb_end_write(file_inode(file)->i_sb);
2875 }
2876 
2877 /**
2878  * kiocb_start_write - get write access to a superblock for async file io
2879  * @iocb: the io context we want to submit the write with
2880  *
2881  * This is a variant of sb_start_write() for async io submission.
2882  * Should be matched with a call to kiocb_end_write().
2883  */
2884 static inline void kiocb_start_write(struct kiocb *iocb)
2885 {
2886 	struct inode *inode = file_inode(iocb->ki_filp);
2887 
2888 	sb_start_write(inode->i_sb);
2889 	/*
2890 	 * Fool lockdep by telling it the lock got released so that it
2891 	 * doesn't complain about the held lock when we return to userspace.
2892 	 */
2893 	__sb_writers_release(inode->i_sb, SB_FREEZE_WRITE);
2894 }
2895 
2896 /**
2897  * kiocb_end_write - drop write access to a superblock after async file io
2898  * @iocb: the io context we sumbitted the write with
2899  *
2900  * Should be matched with a call to kiocb_start_write().
2901  */
2902 static inline void kiocb_end_write(struct kiocb *iocb)
2903 {
2904 	struct inode *inode = file_inode(iocb->ki_filp);
2905 
2906 	/*
2907 	 * Tell lockdep we inherited freeze protection from submission thread.
2908 	 */
2909 	__sb_writers_acquired(inode->i_sb, SB_FREEZE_WRITE);
2910 	sb_end_write(inode->i_sb);
2911 }
2912 
2913 /*
2914  * This is used for regular files where some users -- especially the
2915  * currently executed binary in a process, previously handled via
2916  * VM_DENYWRITE -- cannot handle concurrent write (and maybe mmap
2917  * read-write shared) accesses.
2918  *
2919  * get_write_access() gets write permission for a file.
2920  * put_write_access() releases this write permission.
2921  * deny_write_access() denies write access to a file.
2922  * allow_write_access() re-enables write access to a file.
2923  *
2924  * The i_writecount field of an inode can have the following values:
2925  * 0: no write access, no denied write access
2926  * < 0: (-i_writecount) users that denied write access to the file.
2927  * > 0: (i_writecount) users that have write access to the file.
2928  *
2929  * Normally we operate on that counter with atomic_{inc,dec} and it's safe
2930  * except for the cases where we don't hold i_writecount yet. Then we need to
2931  * use {get,deny}_write_access() - these functions check the sign and refuse
2932  * to do the change if sign is wrong.
2933  */
2934 static inline int get_write_access(struct inode *inode)
2935 {
2936 	return atomic_inc_unless_negative(&inode->i_writecount) ? 0 : -ETXTBSY;
2937 }
2938 static inline int deny_write_access(struct file *file)
2939 {
2940 	struct inode *inode = file_inode(file);
2941 	return atomic_dec_unless_positive(&inode->i_writecount) ? 0 : -ETXTBSY;
2942 }
2943 static inline void put_write_access(struct inode * inode)
2944 {
2945 	atomic_dec(&inode->i_writecount);
2946 }
2947 static inline void allow_write_access(struct file *file)
2948 {
2949 	if (file)
2950 		atomic_inc(&file_inode(file)->i_writecount);
2951 }
2952 static inline bool inode_is_open_for_write(const struct inode *inode)
2953 {
2954 	return atomic_read(&inode->i_writecount) > 0;
2955 }
2956 
2957 #if defined(CONFIG_IMA) || defined(CONFIG_FILE_LOCKING)
2958 static inline void i_readcount_dec(struct inode *inode)
2959 {
2960 	BUG_ON(atomic_dec_return(&inode->i_readcount) < 0);
2961 }
2962 static inline void i_readcount_inc(struct inode *inode)
2963 {
2964 	atomic_inc(&inode->i_readcount);
2965 }
2966 #else
2967 static inline void i_readcount_dec(struct inode *inode)
2968 {
2969 	return;
2970 }
2971 static inline void i_readcount_inc(struct inode *inode)
2972 {
2973 	return;
2974 }
2975 #endif
2976 extern int do_pipe_flags(int *, int);
2977 
2978 extern ssize_t kernel_read(struct file *, void *, size_t, loff_t *);
2979 ssize_t __kernel_read(struct file *file, void *buf, size_t count, loff_t *pos);
2980 extern ssize_t kernel_write(struct file *, const void *, size_t, loff_t *);
2981 extern ssize_t __kernel_write(struct file *, const void *, size_t, loff_t *);
2982 extern struct file * open_exec(const char *);
2983 
2984 /* fs/dcache.c -- generic fs support functions */
2985 extern bool is_subdir(struct dentry *, struct dentry *);
2986 extern bool path_is_under(const struct path *, const struct path *);
2987 
2988 extern char *file_path(struct file *, char *, int);
2989 
2990 /**
2991  * is_dot_dotdot - returns true only if @name is "." or ".."
2992  * @name: file name to check
2993  * @len: length of file name, in bytes
2994  */
2995 static inline bool is_dot_dotdot(const char *name, size_t len)
2996 {
2997 	return len && unlikely(name[0] == '.') &&
2998 		(len == 1 || (len == 2 && name[1] == '.'));
2999 }
3000 
3001 #include <linux/err.h>
3002 
3003 /* needed for stackable file system support */
3004 extern loff_t default_llseek(struct file *file, loff_t offset, int whence);
3005 
3006 extern loff_t vfs_llseek(struct file *file, loff_t offset, int whence);
3007 
3008 extern int inode_init_always(struct super_block *, struct inode *);
3009 extern void inode_init_once(struct inode *);
3010 extern void address_space_init_once(struct address_space *mapping);
3011 extern struct inode * igrab(struct inode *);
3012 extern ino_t iunique(struct super_block *, ino_t);
3013 extern int inode_needs_sync(struct inode *inode);
3014 extern int generic_delete_inode(struct inode *inode);
3015 static inline int generic_drop_inode(struct inode *inode)
3016 {
3017 	return !inode->i_nlink || inode_unhashed(inode);
3018 }
3019 extern void d_mark_dontcache(struct inode *inode);
3020 
3021 extern struct inode *ilookup5_nowait(struct super_block *sb,
3022 		unsigned long hashval, int (*test)(struct inode *, void *),
3023 		void *data);
3024 extern struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
3025 		int (*test)(struct inode *, void *), void *data);
3026 extern struct inode *ilookup(struct super_block *sb, unsigned long ino);
3027 
3028 extern struct inode *inode_insert5(struct inode *inode, unsigned long hashval,
3029 		int (*test)(struct inode *, void *),
3030 		int (*set)(struct inode *, void *),
3031 		void *data);
3032 extern struct inode * iget5_locked(struct super_block *, unsigned long, int (*test)(struct inode *, void *), int (*set)(struct inode *, void *), void *);
3033 extern struct inode * iget_locked(struct super_block *, unsigned long);
3034 extern struct inode *find_inode_nowait(struct super_block *,
3035 				       unsigned long,
3036 				       int (*match)(struct inode *,
3037 						    unsigned long, void *),
3038 				       void *data);
3039 extern struct inode *find_inode_rcu(struct super_block *, unsigned long,
3040 				    int (*)(struct inode *, void *), void *);
3041 extern struct inode *find_inode_by_ino_rcu(struct super_block *, unsigned long);
3042 extern int insert_inode_locked4(struct inode *, unsigned long, int (*test)(struct inode *, void *), void *);
3043 extern int insert_inode_locked(struct inode *);
3044 #ifdef CONFIG_DEBUG_LOCK_ALLOC
3045 extern void lockdep_annotate_inode_mutex_key(struct inode *inode);
3046 #else
3047 static inline void lockdep_annotate_inode_mutex_key(struct inode *inode) { };
3048 #endif
3049 extern void unlock_new_inode(struct inode *);
3050 extern void discard_new_inode(struct inode *);
3051 extern unsigned int get_next_ino(void);
3052 extern void evict_inodes(struct super_block *sb);
3053 void dump_mapping(const struct address_space *);
3054 
3055 /*
3056  * Userspace may rely on the inode number being non-zero. For example, glibc
3057  * simply ignores files with zero i_ino in unlink() and other places.
3058  *
3059  * As an additional complication, if userspace was compiled with
3060  * _FILE_OFFSET_BITS=32 on a 64-bit kernel we'll only end up reading out the
3061  * lower 32 bits, so we need to check that those aren't zero explicitly. With
3062  * _FILE_OFFSET_BITS=64, this may cause some harmless false-negatives, but
3063  * better safe than sorry.
3064  */
3065 static inline bool is_zero_ino(ino_t ino)
3066 {
3067 	return (u32)ino == 0;
3068 }
3069 
3070 extern void __iget(struct inode * inode);
3071 extern void iget_failed(struct inode *);
3072 extern void clear_inode(struct inode *);
3073 extern void __destroy_inode(struct inode *);
3074 extern struct inode *new_inode_pseudo(struct super_block *sb);
3075 extern struct inode *new_inode(struct super_block *sb);
3076 extern void free_inode_nonrcu(struct inode *inode);
3077 extern int setattr_should_drop_suidgid(struct mnt_idmap *, struct inode *);
3078 extern int file_remove_privs_flags(struct file *file, unsigned int flags);
3079 extern int file_remove_privs(struct file *);
3080 int setattr_should_drop_sgid(struct mnt_idmap *idmap,
3081 			     const struct inode *inode);
3082 
3083 /*
3084  * This must be used for allocating filesystems specific inodes to set
3085  * up the inode reclaim context correctly.
3086  */
3087 #define alloc_inode_sb(_sb, _cache, _gfp) kmem_cache_alloc_lru(_cache, &_sb->s_inode_lru, _gfp)
3088 
3089 extern void __insert_inode_hash(struct inode *, unsigned long hashval);
3090 static inline void insert_inode_hash(struct inode *inode)
3091 {
3092 	__insert_inode_hash(inode, inode->i_ino);
3093 }
3094 
3095 extern void __remove_inode_hash(struct inode *);
3096 static inline void remove_inode_hash(struct inode *inode)
3097 {
3098 	if (!inode_unhashed(inode) && !hlist_fake(&inode->i_hash))
3099 		__remove_inode_hash(inode);
3100 }
3101 
3102 extern void inode_sb_list_add(struct inode *inode);
3103 extern void inode_add_lru(struct inode *inode);
3104 
3105 extern int sb_set_blocksize(struct super_block *, int);
3106 extern int sb_min_blocksize(struct super_block *, int);
3107 
3108 extern int generic_file_mmap(struct file *, struct vm_area_struct *);
3109 extern int generic_file_readonly_mmap(struct file *, struct vm_area_struct *);
3110 extern ssize_t generic_write_checks(struct kiocb *, struct iov_iter *);
3111 int generic_write_checks_count(struct kiocb *iocb, loff_t *count);
3112 extern int generic_write_check_limits(struct file *file, loff_t pos,
3113 		loff_t *count);
3114 extern int generic_file_rw_checks(struct file *file_in, struct file *file_out);
3115 ssize_t filemap_read(struct kiocb *iocb, struct iov_iter *to,
3116 		ssize_t already_read);
3117 extern ssize_t generic_file_read_iter(struct kiocb *, struct iov_iter *);
3118 extern ssize_t __generic_file_write_iter(struct kiocb *, struct iov_iter *);
3119 extern ssize_t generic_file_write_iter(struct kiocb *, struct iov_iter *);
3120 extern ssize_t generic_file_direct_write(struct kiocb *, struct iov_iter *);
3121 ssize_t generic_perform_write(struct kiocb *, struct iov_iter *);
3122 ssize_t direct_write_fallback(struct kiocb *iocb, struct iov_iter *iter,
3123 		ssize_t direct_written, ssize_t buffered_written);
3124 
3125 ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos,
3126 		rwf_t flags);
3127 ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos,
3128 		rwf_t flags);
3129 ssize_t vfs_iocb_iter_read(struct file *file, struct kiocb *iocb,
3130 			   struct iov_iter *iter);
3131 ssize_t vfs_iocb_iter_write(struct file *file, struct kiocb *iocb,
3132 			    struct iov_iter *iter);
3133 
3134 /* fs/splice.c */
3135 ssize_t filemap_splice_read(struct file *in, loff_t *ppos,
3136 			    struct pipe_inode_info *pipe,
3137 			    size_t len, unsigned int flags);
3138 ssize_t copy_splice_read(struct file *in, loff_t *ppos,
3139 			 struct pipe_inode_info *pipe,
3140 			 size_t len, unsigned int flags);
3141 extern ssize_t iter_file_splice_write(struct pipe_inode_info *,
3142 		struct file *, loff_t *, size_t, unsigned int);
3143 
3144 
3145 extern void
3146 file_ra_state_init(struct file_ra_state *ra, struct address_space *mapping);
3147 extern loff_t noop_llseek(struct file *file, loff_t offset, int whence);
3148 #define no_llseek NULL
3149 extern loff_t vfs_setpos(struct file *file, loff_t offset, loff_t maxsize);
3150 extern loff_t generic_file_llseek(struct file *file, loff_t offset, int whence);
3151 extern loff_t generic_file_llseek_size(struct file *file, loff_t offset,
3152 		int whence, loff_t maxsize, loff_t eof);
3153 extern loff_t fixed_size_llseek(struct file *file, loff_t offset,
3154 		int whence, loff_t size);
3155 extern loff_t no_seek_end_llseek_size(struct file *, loff_t, int, loff_t);
3156 extern loff_t no_seek_end_llseek(struct file *, loff_t, int);
3157 int rw_verify_area(int, struct file *, const loff_t *, size_t);
3158 extern int generic_file_open(struct inode * inode, struct file * filp);
3159 extern int nonseekable_open(struct inode * inode, struct file * filp);
3160 extern int stream_open(struct inode * inode, struct file * filp);
3161 
3162 #ifdef CONFIG_BLOCK
3163 typedef void (dio_submit_t)(struct bio *bio, struct inode *inode,
3164 			    loff_t file_offset);
3165 
3166 enum {
3167 	/* need locking between buffered and direct access */
3168 	DIO_LOCKING	= 0x01,
3169 
3170 	/* filesystem does not support filling holes */
3171 	DIO_SKIP_HOLES	= 0x02,
3172 };
3173 
3174 ssize_t __blockdev_direct_IO(struct kiocb *iocb, struct inode *inode,
3175 			     struct block_device *bdev, struct iov_iter *iter,
3176 			     get_block_t get_block,
3177 			     dio_iodone_t end_io,
3178 			     int flags);
3179 
3180 static inline ssize_t blockdev_direct_IO(struct kiocb *iocb,
3181 					 struct inode *inode,
3182 					 struct iov_iter *iter,
3183 					 get_block_t get_block)
3184 {
3185 	return __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev, iter,
3186 			get_block, NULL, DIO_LOCKING | DIO_SKIP_HOLES);
3187 }
3188 #endif
3189 
3190 void inode_dio_wait(struct inode *inode);
3191 
3192 /**
3193  * inode_dio_begin - signal start of a direct I/O requests
3194  * @inode: inode the direct I/O happens on
3195  *
3196  * This is called once we've finished processing a direct I/O request,
3197  * and is used to wake up callers waiting for direct I/O to be quiesced.
3198  */
3199 static inline void inode_dio_begin(struct inode *inode)
3200 {
3201 	atomic_inc(&inode->i_dio_count);
3202 }
3203 
3204 /**
3205  * inode_dio_end - signal finish of a direct I/O requests
3206  * @inode: inode the direct I/O happens on
3207  *
3208  * This is called once we've finished processing a direct I/O request,
3209  * and is used to wake up callers waiting for direct I/O to be quiesced.
3210  */
3211 static inline void inode_dio_end(struct inode *inode)
3212 {
3213 	if (atomic_dec_and_test(&inode->i_dio_count))
3214 		wake_up_bit(&inode->i_state, __I_DIO_WAKEUP);
3215 }
3216 
3217 extern void inode_set_flags(struct inode *inode, unsigned int flags,
3218 			    unsigned int mask);
3219 
3220 extern const struct file_operations generic_ro_fops;
3221 
3222 #define special_file(m) (S_ISCHR(m)||S_ISBLK(m)||S_ISFIFO(m)||S_ISSOCK(m))
3223 
3224 extern int readlink_copy(char __user *, int, const char *);
3225 extern int page_readlink(struct dentry *, char __user *, int);
3226 extern const char *page_get_link(struct dentry *, struct inode *,
3227 				 struct delayed_call *);
3228 extern void page_put_link(void *);
3229 extern int page_symlink(struct inode *inode, const char *symname, int len);
3230 extern const struct inode_operations page_symlink_inode_operations;
3231 extern void kfree_link(void *);
3232 void generic_fillattr(struct mnt_idmap *, u32, struct inode *, struct kstat *);
3233 void generic_fill_statx_attr(struct inode *inode, struct kstat *stat);
3234 extern int vfs_getattr_nosec(const struct path *, struct kstat *, u32, unsigned int);
3235 extern int vfs_getattr(const struct path *, struct kstat *, u32, unsigned int);
3236 void __inode_add_bytes(struct inode *inode, loff_t bytes);
3237 void inode_add_bytes(struct inode *inode, loff_t bytes);
3238 void __inode_sub_bytes(struct inode *inode, loff_t bytes);
3239 void inode_sub_bytes(struct inode *inode, loff_t bytes);
3240 static inline loff_t __inode_get_bytes(struct inode *inode)
3241 {
3242 	return (((loff_t)inode->i_blocks) << 9) + inode->i_bytes;
3243 }
3244 loff_t inode_get_bytes(struct inode *inode);
3245 void inode_set_bytes(struct inode *inode, loff_t bytes);
3246 const char *simple_get_link(struct dentry *, struct inode *,
3247 			    struct delayed_call *);
3248 extern const struct inode_operations simple_symlink_inode_operations;
3249 
3250 extern int iterate_dir(struct file *, struct dir_context *);
3251 
3252 int vfs_fstatat(int dfd, const char __user *filename, struct kstat *stat,
3253 		int flags);
3254 int vfs_fstat(int fd, struct kstat *stat);
3255 
3256 static inline int vfs_stat(const char __user *filename, struct kstat *stat)
3257 {
3258 	return vfs_fstatat(AT_FDCWD, filename, stat, 0);
3259 }
3260 static inline int vfs_lstat(const char __user *name, struct kstat *stat)
3261 {
3262 	return vfs_fstatat(AT_FDCWD, name, stat, AT_SYMLINK_NOFOLLOW);
3263 }
3264 
3265 extern const char *vfs_get_link(struct dentry *, struct delayed_call *);
3266 extern int vfs_readlink(struct dentry *, char __user *, int);
3267 
3268 extern struct file_system_type *get_filesystem(struct file_system_type *fs);
3269 extern void put_filesystem(struct file_system_type *fs);
3270 extern struct file_system_type *get_fs_type(const char *name);
3271 extern void drop_super(struct super_block *sb);
3272 extern void drop_super_exclusive(struct super_block *sb);
3273 extern void iterate_supers(void (*)(struct super_block *, void *), void *);
3274 extern void iterate_supers_type(struct file_system_type *,
3275 			        void (*)(struct super_block *, void *), void *);
3276 
3277 extern int dcache_dir_open(struct inode *, struct file *);
3278 extern int dcache_dir_close(struct inode *, struct file *);
3279 extern loff_t dcache_dir_lseek(struct file *, loff_t, int);
3280 extern int dcache_readdir(struct file *, struct dir_context *);
3281 extern int simple_setattr(struct mnt_idmap *, struct dentry *,
3282 			  struct iattr *);
3283 extern int simple_getattr(struct mnt_idmap *, const struct path *,
3284 			  struct kstat *, u32, unsigned int);
3285 extern int simple_statfs(struct dentry *, struct kstatfs *);
3286 extern int simple_open(struct inode *inode, struct file *file);
3287 extern int simple_link(struct dentry *, struct inode *, struct dentry *);
3288 extern int simple_unlink(struct inode *, struct dentry *);
3289 extern int simple_rmdir(struct inode *, struct dentry *);
3290 void simple_rename_timestamp(struct inode *old_dir, struct dentry *old_dentry,
3291 			     struct inode *new_dir, struct dentry *new_dentry);
3292 extern int simple_rename_exchange(struct inode *old_dir, struct dentry *old_dentry,
3293 				  struct inode *new_dir, struct dentry *new_dentry);
3294 extern int simple_rename(struct mnt_idmap *, struct inode *,
3295 			 struct dentry *, struct inode *, struct dentry *,
3296 			 unsigned int);
3297 extern void simple_recursive_removal(struct dentry *,
3298                               void (*callback)(struct dentry *));
3299 extern int noop_fsync(struct file *, loff_t, loff_t, int);
3300 extern ssize_t noop_direct_IO(struct kiocb *iocb, struct iov_iter *iter);
3301 extern int simple_empty(struct dentry *);
3302 extern int simple_write_begin(struct file *file, struct address_space *mapping,
3303 			loff_t pos, unsigned len,
3304 			struct page **pagep, void **fsdata);
3305 extern const struct address_space_operations ram_aops;
3306 extern int always_delete_dentry(const struct dentry *);
3307 extern struct inode *alloc_anon_inode(struct super_block *);
3308 extern int simple_nosetlease(struct file *, int, struct file_lease **, void **);
3309 extern const struct dentry_operations simple_dentry_operations;
3310 
3311 extern struct dentry *simple_lookup(struct inode *, struct dentry *, unsigned int flags);
3312 extern ssize_t generic_read_dir(struct file *, char __user *, size_t, loff_t *);
3313 extern const struct file_operations simple_dir_operations;
3314 extern const struct inode_operations simple_dir_inode_operations;
3315 extern void make_empty_dir_inode(struct inode *inode);
3316 extern bool is_empty_dir_inode(struct inode *inode);
3317 struct tree_descr { const char *name; const struct file_operations *ops; int mode; };
3318 struct dentry *d_alloc_name(struct dentry *, const char *);
3319 extern int simple_fill_super(struct super_block *, unsigned long,
3320 			     const struct tree_descr *);
3321 extern int simple_pin_fs(struct file_system_type *, struct vfsmount **mount, int *count);
3322 extern void simple_release_fs(struct vfsmount **mount, int *count);
3323 
3324 extern ssize_t simple_read_from_buffer(void __user *to, size_t count,
3325 			loff_t *ppos, const void *from, size_t available);
3326 extern ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos,
3327 		const void __user *from, size_t count);
3328 
3329 struct offset_ctx {
3330 	struct maple_tree	mt;
3331 	unsigned long		next_offset;
3332 };
3333 
3334 void simple_offset_init(struct offset_ctx *octx);
3335 int simple_offset_add(struct offset_ctx *octx, struct dentry *dentry);
3336 void simple_offset_remove(struct offset_ctx *octx, struct dentry *dentry);
3337 int simple_offset_empty(struct dentry *dentry);
3338 int simple_offset_rename(struct inode *old_dir, struct dentry *old_dentry,
3339 			 struct inode *new_dir, struct dentry *new_dentry);
3340 int simple_offset_rename_exchange(struct inode *old_dir,
3341 				  struct dentry *old_dentry,
3342 				  struct inode *new_dir,
3343 				  struct dentry *new_dentry);
3344 void simple_offset_destroy(struct offset_ctx *octx);
3345 
3346 extern const struct file_operations simple_offset_dir_operations;
3347 
3348 extern int __generic_file_fsync(struct file *, loff_t, loff_t, int);
3349 extern int generic_file_fsync(struct file *, loff_t, loff_t, int);
3350 
3351 extern int generic_check_addressable(unsigned, u64);
3352 
3353 extern void generic_set_sb_d_ops(struct super_block *sb);
3354 
3355 static inline bool sb_has_encoding(const struct super_block *sb)
3356 {
3357 #if IS_ENABLED(CONFIG_UNICODE)
3358 	return !!sb->s_encoding;
3359 #else
3360 	return false;
3361 #endif
3362 }
3363 
3364 int may_setattr(struct mnt_idmap *idmap, struct inode *inode,
3365 		unsigned int ia_valid);
3366 int setattr_prepare(struct mnt_idmap *, struct dentry *, struct iattr *);
3367 extern int inode_newsize_ok(const struct inode *, loff_t offset);
3368 void setattr_copy(struct mnt_idmap *, struct inode *inode,
3369 		  const struct iattr *attr);
3370 
3371 extern int file_update_time(struct file *file);
3372 
3373 static inline bool vma_is_dax(const struct vm_area_struct *vma)
3374 {
3375 	return vma->vm_file && IS_DAX(vma->vm_file->f_mapping->host);
3376 }
3377 
3378 static inline bool vma_is_fsdax(struct vm_area_struct *vma)
3379 {
3380 	struct inode *inode;
3381 
3382 	if (!IS_ENABLED(CONFIG_FS_DAX) || !vma->vm_file)
3383 		return false;
3384 	if (!vma_is_dax(vma))
3385 		return false;
3386 	inode = file_inode(vma->vm_file);
3387 	if (S_ISCHR(inode->i_mode))
3388 		return false; /* device-dax */
3389 	return true;
3390 }
3391 
3392 static inline int iocb_flags(struct file *file)
3393 {
3394 	int res = 0;
3395 	if (file->f_flags & O_APPEND)
3396 		res |= IOCB_APPEND;
3397 	if (file->f_flags & O_DIRECT)
3398 		res |= IOCB_DIRECT;
3399 	if (file->f_flags & O_DSYNC)
3400 		res |= IOCB_DSYNC;
3401 	if (file->f_flags & __O_SYNC)
3402 		res |= IOCB_SYNC;
3403 	return res;
3404 }
3405 
3406 static inline int kiocb_set_rw_flags(struct kiocb *ki, rwf_t flags)
3407 {
3408 	int kiocb_flags = 0;
3409 
3410 	/* make sure there's no overlap between RWF and private IOCB flags */
3411 	BUILD_BUG_ON((__force int) RWF_SUPPORTED & IOCB_EVENTFD);
3412 
3413 	if (!flags)
3414 		return 0;
3415 	if (unlikely(flags & ~RWF_SUPPORTED))
3416 		return -EOPNOTSUPP;
3417 	if (unlikely((flags & RWF_APPEND) && (flags & RWF_NOAPPEND)))
3418 		return -EINVAL;
3419 
3420 	if (flags & RWF_NOWAIT) {
3421 		if (!(ki->ki_filp->f_mode & FMODE_NOWAIT))
3422 			return -EOPNOTSUPP;
3423 		kiocb_flags |= IOCB_NOIO;
3424 	}
3425 	kiocb_flags |= (__force int) (flags & RWF_SUPPORTED);
3426 	if (flags & RWF_SYNC)
3427 		kiocb_flags |= IOCB_DSYNC;
3428 
3429 	if ((flags & RWF_NOAPPEND) && (ki->ki_flags & IOCB_APPEND)) {
3430 		if (IS_APPEND(file_inode(ki->ki_filp)))
3431 			return -EPERM;
3432 		ki->ki_flags &= ~IOCB_APPEND;
3433 	}
3434 
3435 	ki->ki_flags |= kiocb_flags;
3436 	return 0;
3437 }
3438 
3439 static inline ino_t parent_ino(struct dentry *dentry)
3440 {
3441 	ino_t res;
3442 
3443 	/*
3444 	 * Don't strictly need d_lock here? If the parent ino could change
3445 	 * then surely we'd have a deeper race in the caller?
3446 	 */
3447 	spin_lock(&dentry->d_lock);
3448 	res = dentry->d_parent->d_inode->i_ino;
3449 	spin_unlock(&dentry->d_lock);
3450 	return res;
3451 }
3452 
3453 /* Transaction based IO helpers */
3454 
3455 /*
3456  * An argresp is stored in an allocated page and holds the
3457  * size of the argument or response, along with its content
3458  */
3459 struct simple_transaction_argresp {
3460 	ssize_t size;
3461 	char data[];
3462 };
3463 
3464 #define SIMPLE_TRANSACTION_LIMIT (PAGE_SIZE - sizeof(struct simple_transaction_argresp))
3465 
3466 char *simple_transaction_get(struct file *file, const char __user *buf,
3467 				size_t size);
3468 ssize_t simple_transaction_read(struct file *file, char __user *buf,
3469 				size_t size, loff_t *pos);
3470 int simple_transaction_release(struct inode *inode, struct file *file);
3471 
3472 void simple_transaction_set(struct file *file, size_t n);
3473 
3474 /*
3475  * simple attribute files
3476  *
3477  * These attributes behave similar to those in sysfs:
3478  *
3479  * Writing to an attribute immediately sets a value, an open file can be
3480  * written to multiple times.
3481  *
3482  * Reading from an attribute creates a buffer from the value that might get
3483  * read with multiple read calls. When the attribute has been read
3484  * completely, no further read calls are possible until the file is opened
3485  * again.
3486  *
3487  * All attributes contain a text representation of a numeric value
3488  * that are accessed with the get() and set() functions.
3489  */
3490 #define DEFINE_SIMPLE_ATTRIBUTE_XSIGNED(__fops, __get, __set, __fmt, __is_signed)	\
3491 static int __fops ## _open(struct inode *inode, struct file *file)	\
3492 {									\
3493 	__simple_attr_check_format(__fmt, 0ull);			\
3494 	return simple_attr_open(inode, file, __get, __set, __fmt);	\
3495 }									\
3496 static const struct file_operations __fops = {				\
3497 	.owner	 = THIS_MODULE,						\
3498 	.open	 = __fops ## _open,					\
3499 	.release = simple_attr_release,					\
3500 	.read	 = simple_attr_read,					\
3501 	.write	 = (__is_signed) ? simple_attr_write_signed : simple_attr_write,	\
3502 	.llseek	 = generic_file_llseek,					\
3503 }
3504 
3505 #define DEFINE_SIMPLE_ATTRIBUTE(__fops, __get, __set, __fmt)		\
3506 	DEFINE_SIMPLE_ATTRIBUTE_XSIGNED(__fops, __get, __set, __fmt, false)
3507 
3508 #define DEFINE_SIMPLE_ATTRIBUTE_SIGNED(__fops, __get, __set, __fmt)	\
3509 	DEFINE_SIMPLE_ATTRIBUTE_XSIGNED(__fops, __get, __set, __fmt, true)
3510 
3511 static inline __printf(1, 2)
3512 void __simple_attr_check_format(const char *fmt, ...)
3513 {
3514 	/* don't do anything, just let the compiler check the arguments; */
3515 }
3516 
3517 int simple_attr_open(struct inode *inode, struct file *file,
3518 		     int (*get)(void *, u64 *), int (*set)(void *, u64),
3519 		     const char *fmt);
3520 int simple_attr_release(struct inode *inode, struct file *file);
3521 ssize_t simple_attr_read(struct file *file, char __user *buf,
3522 			 size_t len, loff_t *ppos);
3523 ssize_t simple_attr_write(struct file *file, const char __user *buf,
3524 			  size_t len, loff_t *ppos);
3525 ssize_t simple_attr_write_signed(struct file *file, const char __user *buf,
3526 				 size_t len, loff_t *ppos);
3527 
3528 struct ctl_table;
3529 int __init list_bdev_fs_names(char *buf, size_t size);
3530 
3531 #define __FMODE_EXEC		((__force int) FMODE_EXEC)
3532 #define __FMODE_NONOTIFY	((__force int) FMODE_NONOTIFY)
3533 
3534 #define ACC_MODE(x) ("\004\002\006\006"[(x)&O_ACCMODE])
3535 #define OPEN_FMODE(flag) ((__force fmode_t)(((flag + 1) & O_ACCMODE) | \
3536 					    (flag & __FMODE_NONOTIFY)))
3537 
3538 static inline bool is_sxid(umode_t mode)
3539 {
3540 	return mode & (S_ISUID | S_ISGID);
3541 }
3542 
3543 static inline int check_sticky(struct mnt_idmap *idmap,
3544 			       struct inode *dir, struct inode *inode)
3545 {
3546 	if (!(dir->i_mode & S_ISVTX))
3547 		return 0;
3548 
3549 	return __check_sticky(idmap, dir, inode);
3550 }
3551 
3552 static inline void inode_has_no_xattr(struct inode *inode)
3553 {
3554 	if (!is_sxid(inode->i_mode) && (inode->i_sb->s_flags & SB_NOSEC))
3555 		inode->i_flags |= S_NOSEC;
3556 }
3557 
3558 static inline bool is_root_inode(struct inode *inode)
3559 {
3560 	return inode == inode->i_sb->s_root->d_inode;
3561 }
3562 
3563 static inline bool dir_emit(struct dir_context *ctx,
3564 			    const char *name, int namelen,
3565 			    u64 ino, unsigned type)
3566 {
3567 	return ctx->actor(ctx, name, namelen, ctx->pos, ino, type);
3568 }
3569 static inline bool dir_emit_dot(struct file *file, struct dir_context *ctx)
3570 {
3571 	return ctx->actor(ctx, ".", 1, ctx->pos,
3572 			  file->f_path.dentry->d_inode->i_ino, DT_DIR);
3573 }
3574 static inline bool dir_emit_dotdot(struct file *file, struct dir_context *ctx)
3575 {
3576 	return ctx->actor(ctx, "..", 2, ctx->pos,
3577 			  parent_ino(file->f_path.dentry), DT_DIR);
3578 }
3579 static inline bool dir_emit_dots(struct file *file, struct dir_context *ctx)
3580 {
3581 	if (ctx->pos == 0) {
3582 		if (!dir_emit_dot(file, ctx))
3583 			return false;
3584 		ctx->pos = 1;
3585 	}
3586 	if (ctx->pos == 1) {
3587 		if (!dir_emit_dotdot(file, ctx))
3588 			return false;
3589 		ctx->pos = 2;
3590 	}
3591 	return true;
3592 }
3593 static inline bool dir_relax(struct inode *inode)
3594 {
3595 	inode_unlock(inode);
3596 	inode_lock(inode);
3597 	return !IS_DEADDIR(inode);
3598 }
3599 
3600 static inline bool dir_relax_shared(struct inode *inode)
3601 {
3602 	inode_unlock_shared(inode);
3603 	inode_lock_shared(inode);
3604 	return !IS_DEADDIR(inode);
3605 }
3606 
3607 extern bool path_noexec(const struct path *path);
3608 extern void inode_nohighmem(struct inode *inode);
3609 
3610 /* mm/fadvise.c */
3611 extern int vfs_fadvise(struct file *file, loff_t offset, loff_t len,
3612 		       int advice);
3613 extern int generic_fadvise(struct file *file, loff_t offset, loff_t len,
3614 			   int advice);
3615 
3616 #endif /* _LINUX_FS_H */
3617