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 fs_context;
77 struct fs_parameter_spec;
78 struct fileattr;
79 struct iomap_ops;
80
81 extern void __init inode_init(void);
82 extern void __init inode_init_early(void);
83 extern void __init files_init(void);
84 extern void __init files_maxfiles_init(void);
85
86 extern unsigned long get_max_files(void);
87 extern unsigned int sysctl_nr_open;
88
89 typedef __kernel_rwf_t rwf_t;
90
91 struct buffer_head;
92 typedef int (get_block_t)(struct inode *inode, sector_t iblock,
93 struct buffer_head *bh_result, int create);
94 typedef int (dio_iodone_t)(struct kiocb *iocb, loff_t offset,
95 ssize_t bytes, void *private);
96
97 #define MAY_EXEC 0x00000001
98 #define MAY_WRITE 0x00000002
99 #define MAY_READ 0x00000004
100 #define MAY_APPEND 0x00000008
101 #define MAY_ACCESS 0x00000010
102 #define MAY_OPEN 0x00000020
103 #define MAY_CHDIR 0x00000040
104 /* called from RCU mode, don't block */
105 #define MAY_NOT_BLOCK 0x00000080
106
107 /*
108 * flags in file.f_mode. Note that FMODE_READ and FMODE_WRITE must correspond
109 * to O_WRONLY and O_RDWR via the strange trick in do_dentry_open()
110 */
111
112 /* file is open for reading */
113 #define FMODE_READ ((__force fmode_t)(1 << 0))
114 /* file is open for writing */
115 #define FMODE_WRITE ((__force fmode_t)(1 << 1))
116 /* file is seekable */
117 #define FMODE_LSEEK ((__force fmode_t)(1 << 2))
118 /* file can be accessed using pread */
119 #define FMODE_PREAD ((__force fmode_t)(1 << 3))
120 /* file can be accessed using pwrite */
121 #define FMODE_PWRITE ((__force fmode_t)(1 << 4))
122 /* File is opened for execution with sys_execve / sys_uselib */
123 #define FMODE_EXEC ((__force fmode_t)(1 << 5))
124 /* File writes are restricted (block device specific) */
125 #define FMODE_WRITE_RESTRICTED ((__force fmode_t)(1 << 6))
126
127 /* FMODE_* bits 7 to 8 */
128
129 /* 32bit hashes as llseek() offset (for directories) */
130 #define FMODE_32BITHASH ((__force fmode_t)(1 << 9))
131 /* 64bit hashes as llseek() offset (for directories) */
132 #define FMODE_64BITHASH ((__force fmode_t)(1 << 10))
133
134 /*
135 * Don't update ctime and mtime.
136 *
137 * Currently a special hack for the XFS open_by_handle ioctl, but we'll
138 * hopefully graduate it to a proper O_CMTIME flag supported by open(2) soon.
139 */
140 #define FMODE_NOCMTIME ((__force fmode_t)(1 << 11))
141
142 /* Expect random access pattern */
143 #define FMODE_RANDOM ((__force fmode_t)(1 << 12))
144
145 /* File is huge (eg. /dev/mem): treat loff_t as unsigned */
146 #define FMODE_UNSIGNED_OFFSET ((__force fmode_t)(1 << 13))
147
148 /* File is opened with O_PATH; almost nothing can be done with it */
149 #define FMODE_PATH ((__force fmode_t)(1 << 14))
150
151 /* File needs atomic accesses to f_pos */
152 #define FMODE_ATOMIC_POS ((__force fmode_t)(1 << 15))
153 /* Write access to underlying fs */
154 #define FMODE_WRITER ((__force fmode_t)(1 << 16))
155 /* Has read method(s) */
156 #define FMODE_CAN_READ ((__force fmode_t)(1 << 17))
157 /* Has write method(s) */
158 #define FMODE_CAN_WRITE ((__force fmode_t)(1 << 18))
159
160 #define FMODE_OPENED ((__force fmode_t)(1 << 19))
161 #define FMODE_CREATED ((__force fmode_t)(1 << 20))
162
163 /* File is stream-like */
164 #define FMODE_STREAM ((__force fmode_t)(1 << 21))
165
166 /* File supports DIRECT IO */
167 #define FMODE_CAN_ODIRECT ((__force fmode_t)(1 << 22))
168
169 #define FMODE_NOREUSE ((__force fmode_t)(1 << 23))
170
171 /* FMODE_* bit 24 */
172
173 /* File is embedded in backing_file object */
174 #define FMODE_BACKING ((__force fmode_t)(1 << 25))
175
176 /* File was opened by fanotify and shouldn't generate fanotify events */
177 #define FMODE_NONOTIFY ((__force fmode_t)(1 << 26))
178
179 /* File is capable of returning -EAGAIN if I/O will block */
180 #define FMODE_NOWAIT ((__force fmode_t)(1 << 27))
181
182 /* File represents mount that needs unmounting */
183 #define FMODE_NEED_UNMOUNT ((__force fmode_t)(1 << 28))
184
185 /* File does not contribute to nr_files count */
186 #define FMODE_NOACCOUNT ((__force fmode_t)(1 << 29))
187
188 /*
189 * Attribute flags. These should be or-ed together to figure out what
190 * has been changed!
191 */
192 #define ATTR_MODE (1 << 0)
193 #define ATTR_UID (1 << 1)
194 #define ATTR_GID (1 << 2)
195 #define ATTR_SIZE (1 << 3)
196 #define ATTR_ATIME (1 << 4)
197 #define ATTR_MTIME (1 << 5)
198 #define ATTR_CTIME (1 << 6)
199 #define ATTR_ATIME_SET (1 << 7)
200 #define ATTR_MTIME_SET (1 << 8)
201 #define ATTR_FORCE (1 << 9) /* Not a change, but a change it */
202 #define ATTR_KILL_SUID (1 << 11)
203 #define ATTR_KILL_SGID (1 << 12)
204 #define ATTR_FILE (1 << 13)
205 #define ATTR_KILL_PRIV (1 << 14)
206 #define ATTR_OPEN (1 << 15) /* Truncating from open(O_TRUNC) */
207 #define ATTR_TIMES_SET (1 << 16)
208 #define ATTR_TOUCH (1 << 17)
209
210 /*
211 * Whiteout is represented by a char device. The following constants define the
212 * mode and device number to use.
213 */
214 #define WHITEOUT_MODE 0
215 #define WHITEOUT_DEV 0
216
217 /*
218 * This is the Inode Attributes structure, used for notify_change(). It
219 * uses the above definitions as flags, to know which values have changed.
220 * Also, in this manner, a Filesystem can look at only the values it cares
221 * about. Basically, these are the attributes that the VFS layer can
222 * request to change from the FS layer.
223 *
224 * Derek Atkins <warlord@MIT.EDU> 94-10-20
225 */
226 struct iattr {
227 unsigned int ia_valid;
228 umode_t ia_mode;
229 /*
230 * The two anonymous unions wrap structures with the same member.
231 *
232 * Filesystems raising FS_ALLOW_IDMAP need to use ia_vfs{g,u}id which
233 * are a dedicated type requiring the filesystem to use the dedicated
234 * helpers. Other filesystem can continue to use ia_{g,u}id until they
235 * have been ported.
236 *
237 * They always contain the same value. In other words FS_ALLOW_IDMAP
238 * pass down the same value on idmapped mounts as they would on regular
239 * mounts.
240 */
241 union {
242 kuid_t ia_uid;
243 vfsuid_t ia_vfsuid;
244 };
245 union {
246 kgid_t ia_gid;
247 vfsgid_t ia_vfsgid;
248 };
249 loff_t ia_size;
250 struct timespec64 ia_atime;
251 struct timespec64 ia_mtime;
252 struct timespec64 ia_ctime;
253
254 /*
255 * Not an attribute, but an auxiliary info for filesystems wanting to
256 * implement an ftruncate() like method. NOTE: filesystem should
257 * check for (ia_valid & ATTR_FILE), and not for (ia_file != NULL).
258 */
259 struct file *ia_file;
260 };
261
262 /*
263 * Includes for diskquotas.
264 */
265 #include <linux/quota.h>
266
267 /*
268 * Maximum number of layers of fs stack. Needs to be limited to
269 * prevent kernel stack overflow
270 */
271 #define FILESYSTEM_MAX_STACK_DEPTH 2
272
273 /**
274 * enum positive_aop_returns - aop return codes with specific semantics
275 *
276 * @AOP_WRITEPAGE_ACTIVATE: Informs the caller that page writeback has
277 * completed, that the page is still locked, and
278 * should be considered active. The VM uses this hint
279 * to return the page to the active list -- it won't
280 * be a candidate for writeback again in the near
281 * future. Other callers must be careful to unlock
282 * the page if they get this return. Returned by
283 * writepage();
284 *
285 * @AOP_TRUNCATED_PAGE: The AOP method that was handed a locked page has
286 * unlocked it and the page might have been truncated.
287 * The caller should back up to acquiring a new page and
288 * trying again. The aop will be taking reasonable
289 * precautions not to livelock. If the caller held a page
290 * reference, it should drop it before retrying. Returned
291 * by read_folio().
292 *
293 * address_space_operation functions return these large constants to indicate
294 * special semantics to the caller. These are much larger than the bytes in a
295 * page to allow for functions that return the number of bytes operated on in a
296 * given page.
297 */
298
299 enum positive_aop_returns {
300 AOP_WRITEPAGE_ACTIVATE = 0x80000,
301 AOP_TRUNCATED_PAGE = 0x80001,
302 };
303
304 /*
305 * oh the beauties of C type declarations.
306 */
307 struct page;
308 struct address_space;
309 struct writeback_control;
310 struct readahead_control;
311
312 /* Match RWF_* bits to IOCB bits */
313 #define IOCB_HIPRI (__force int) RWF_HIPRI
314 #define IOCB_DSYNC (__force int) RWF_DSYNC
315 #define IOCB_SYNC (__force int) RWF_SYNC
316 #define IOCB_NOWAIT (__force int) RWF_NOWAIT
317 #define IOCB_APPEND (__force int) RWF_APPEND
318
319 /* non-RWF related bits - start at 16 */
320 #define IOCB_EVENTFD (1 << 16)
321 #define IOCB_DIRECT (1 << 17)
322 #define IOCB_WRITE (1 << 18)
323 /* iocb->ki_waitq is valid */
324 #define IOCB_WAITQ (1 << 19)
325 #define IOCB_NOIO (1 << 20)
326 /* can use bio alloc cache */
327 #define IOCB_ALLOC_CACHE (1 << 21)
328 /*
329 * IOCB_DIO_CALLER_COMP can be set by the iocb owner, to indicate that the
330 * iocb completion can be passed back to the owner for execution from a safe
331 * context rather than needing to be punted through a workqueue. If this
332 * flag is set, the bio completion handling may set iocb->dio_complete to a
333 * handler function and iocb->private to context information for that handler.
334 * The issuer should call the handler with that context information from task
335 * context to complete the processing of the iocb. Note that while this
336 * provides a task context for the dio_complete() callback, it should only be
337 * used on the completion side for non-IO generating completions. It's fine to
338 * call blocking functions from this callback, but they should not wait for
339 * unrelated IO (like cache flushing, new IO generation, etc).
340 */
341 #define IOCB_DIO_CALLER_COMP (1 << 22)
342 /* kiocb is a read or write operation submitted by fs/aio.c. */
343 #define IOCB_AIO_RW (1 << 23)
344
345 /* for use in trace events */
346 #define TRACE_IOCB_STRINGS \
347 { IOCB_HIPRI, "HIPRI" }, \
348 { IOCB_DSYNC, "DSYNC" }, \
349 { IOCB_SYNC, "SYNC" }, \
350 { IOCB_NOWAIT, "NOWAIT" }, \
351 { IOCB_APPEND, "APPEND" }, \
352 { IOCB_EVENTFD, "EVENTFD"}, \
353 { IOCB_DIRECT, "DIRECT" }, \
354 { IOCB_WRITE, "WRITE" }, \
355 { IOCB_WAITQ, "WAITQ" }, \
356 { IOCB_NOIO, "NOIO" }, \
357 { IOCB_ALLOC_CACHE, "ALLOC_CACHE" }, \
358 { IOCB_DIO_CALLER_COMP, "CALLER_COMP" }
359
360 struct kiocb {
361 struct file *ki_filp;
362 loff_t ki_pos;
363 void (*ki_complete)(struct kiocb *iocb, long ret);
364 void *private;
365 int ki_flags;
366 u16 ki_ioprio; /* See linux/ioprio.h */
367 union {
368 /*
369 * Only used for async buffered reads, where it denotes the
370 * page waitqueue associated with completing the read. Valid
371 * IFF IOCB_WAITQ is set.
372 */
373 struct wait_page_queue *ki_waitq;
374 /*
375 * Can be used for O_DIRECT IO, where the completion handling
376 * is punted back to the issuer of the IO. May only be set
377 * if IOCB_DIO_CALLER_COMP is set by the issuer, and the issuer
378 * must then check for presence of this handler when ki_complete
379 * is invoked. The data passed in to this handler must be
380 * assigned to ->private when dio_complete is assigned.
381 */
382 ssize_t (*dio_complete)(void *data);
383 };
384 };
385
is_sync_kiocb(struct kiocb * kiocb)386 static inline bool is_sync_kiocb(struct kiocb *kiocb)
387 {
388 return kiocb->ki_complete == NULL;
389 }
390
391 struct address_space_operations {
392 int (*writepage)(struct page *page, struct writeback_control *wbc);
393 int (*read_folio)(struct file *, struct folio *);
394
395 /* Write back some dirty pages from this mapping. */
396 int (*writepages)(struct address_space *, struct writeback_control *);
397
398 /* Mark a folio dirty. Return true if this dirtied it */
399 bool (*dirty_folio)(struct address_space *, struct folio *);
400
401 void (*readahead)(struct readahead_control *);
402
403 int (*write_begin)(struct file *, struct address_space *mapping,
404 loff_t pos, unsigned len,
405 struct page **pagep, void **fsdata);
406 int (*write_end)(struct file *, struct address_space *mapping,
407 loff_t pos, unsigned len, unsigned copied,
408 struct page *page, void *fsdata);
409
410 /* Unfortunately this kludge is needed for FIBMAP. Don't use it */
411 sector_t (*bmap)(struct address_space *, sector_t);
412 void (*invalidate_folio) (struct folio *, size_t offset, size_t len);
413 bool (*release_folio)(struct folio *, gfp_t);
414 void (*free_folio)(struct folio *folio);
415 ssize_t (*direct_IO)(struct kiocb *, struct iov_iter *iter);
416 /*
417 * migrate the contents of a folio to the specified target. If
418 * migrate_mode is MIGRATE_ASYNC, it must not block.
419 */
420 int (*migrate_folio)(struct address_space *, struct folio *dst,
421 struct folio *src, enum migrate_mode);
422 int (*launder_folio)(struct folio *);
423 bool (*is_partially_uptodate) (struct folio *, size_t from,
424 size_t count);
425 void (*is_dirty_writeback) (struct folio *, bool *dirty, bool *wb);
426 int (*error_remove_folio)(struct address_space *, struct folio *);
427
428 /* swapfile support */
429 int (*swap_activate)(struct swap_info_struct *sis, struct file *file,
430 sector_t *span);
431 void (*swap_deactivate)(struct file *file);
432 int (*swap_rw)(struct kiocb *iocb, struct iov_iter *iter);
433 };
434
435 extern const struct address_space_operations empty_aops;
436
437 /**
438 * struct address_space - Contents of a cacheable, mappable object.
439 * @host: Owner, either the inode or the block_device.
440 * @i_pages: Cached pages.
441 * @invalidate_lock: Guards coherency between page cache contents and
442 * file offset->disk block mappings in the filesystem during invalidates.
443 * It is also used to block modification of page cache contents through
444 * memory mappings.
445 * @gfp_mask: Memory allocation flags to use for allocating pages.
446 * @i_mmap_writable: Number of VM_SHARED, VM_MAYWRITE mappings.
447 * @nr_thps: Number of THPs in the pagecache (non-shmem only).
448 * @i_mmap: Tree of private and shared mappings.
449 * @i_mmap_rwsem: Protects @i_mmap and @i_mmap_writable.
450 * @nrpages: Number of page entries, protected by the i_pages lock.
451 * @writeback_index: Writeback starts here.
452 * @a_ops: Methods.
453 * @flags: Error bits and flags (AS_*).
454 * @wb_err: The most recent error which has occurred.
455 * @i_private_lock: For use by the owner of the address_space.
456 * @i_private_list: For use by the owner of the address_space.
457 * @i_private_data: For use by the owner of the address_space.
458 */
459 struct address_space {
460 struct inode *host;
461 struct xarray i_pages;
462 struct rw_semaphore invalidate_lock;
463 gfp_t gfp_mask;
464 atomic_t i_mmap_writable;
465 #ifdef CONFIG_READ_ONLY_THP_FOR_FS
466 /* number of thp, only for non-shmem files */
467 atomic_t nr_thps;
468 #endif
469 struct rb_root_cached i_mmap;
470 unsigned long nrpages;
471 pgoff_t writeback_index;
472 const struct address_space_operations *a_ops;
473 unsigned long flags;
474 errseq_t wb_err;
475 spinlock_t i_private_lock;
476 struct list_head i_private_list;
477 struct rw_semaphore i_mmap_rwsem;
478 void * i_private_data;
479 } __attribute__((aligned(sizeof(long)))) __randomize_layout;
480 /*
481 * On most architectures that alignment is already the case; but
482 * must be enforced here for CRIS, to let the least significant bit
483 * of struct page's "mapping" pointer be used for PAGE_MAPPING_ANON.
484 */
485
486 /* XArray tags, for tagging dirty and writeback pages in the pagecache. */
487 #define PAGECACHE_TAG_DIRTY XA_MARK_0
488 #define PAGECACHE_TAG_WRITEBACK XA_MARK_1
489 #define PAGECACHE_TAG_TOWRITE XA_MARK_2
490
491 /*
492 * Returns true if any of the pages in the mapping are marked with the tag.
493 */
mapping_tagged(struct address_space * mapping,xa_mark_t tag)494 static inline bool mapping_tagged(struct address_space *mapping, xa_mark_t tag)
495 {
496 return xa_marked(&mapping->i_pages, tag);
497 }
498
i_mmap_lock_write(struct address_space * mapping)499 static inline void i_mmap_lock_write(struct address_space *mapping)
500 {
501 down_write(&mapping->i_mmap_rwsem);
502 }
503
i_mmap_trylock_write(struct address_space * mapping)504 static inline int i_mmap_trylock_write(struct address_space *mapping)
505 {
506 return down_write_trylock(&mapping->i_mmap_rwsem);
507 }
508
i_mmap_unlock_write(struct address_space * mapping)509 static inline void i_mmap_unlock_write(struct address_space *mapping)
510 {
511 up_write(&mapping->i_mmap_rwsem);
512 }
513
i_mmap_trylock_read(struct address_space * mapping)514 static inline int i_mmap_trylock_read(struct address_space *mapping)
515 {
516 return down_read_trylock(&mapping->i_mmap_rwsem);
517 }
518
i_mmap_lock_read(struct address_space * mapping)519 static inline void i_mmap_lock_read(struct address_space *mapping)
520 {
521 down_read(&mapping->i_mmap_rwsem);
522 }
523
i_mmap_unlock_read(struct address_space * mapping)524 static inline void i_mmap_unlock_read(struct address_space *mapping)
525 {
526 up_read(&mapping->i_mmap_rwsem);
527 }
528
i_mmap_assert_locked(struct address_space * mapping)529 static inline void i_mmap_assert_locked(struct address_space *mapping)
530 {
531 lockdep_assert_held(&mapping->i_mmap_rwsem);
532 }
533
i_mmap_assert_write_locked(struct address_space * mapping)534 static inline void i_mmap_assert_write_locked(struct address_space *mapping)
535 {
536 lockdep_assert_held_write(&mapping->i_mmap_rwsem);
537 }
538
539 /*
540 * Might pages of this file be mapped into userspace?
541 */
mapping_mapped(struct address_space * mapping)542 static inline int mapping_mapped(struct address_space *mapping)
543 {
544 return !RB_EMPTY_ROOT(&mapping->i_mmap.rb_root);
545 }
546
547 /*
548 * Might pages of this file have been modified in userspace?
549 * Note that i_mmap_writable counts all VM_SHARED, VM_MAYWRITE vmas: do_mmap
550 * marks vma as VM_SHARED if it is shared, and the file was opened for
551 * writing i.e. vma may be mprotected writable even if now readonly.
552 *
553 * If i_mmap_writable is negative, no new writable mappings are allowed. You
554 * can only deny writable mappings, if none exists right now.
555 */
mapping_writably_mapped(struct address_space * mapping)556 static inline int mapping_writably_mapped(struct address_space *mapping)
557 {
558 return atomic_read(&mapping->i_mmap_writable) > 0;
559 }
560
mapping_map_writable(struct address_space * mapping)561 static inline int mapping_map_writable(struct address_space *mapping)
562 {
563 return atomic_inc_unless_negative(&mapping->i_mmap_writable) ?
564 0 : -EPERM;
565 }
566
mapping_unmap_writable(struct address_space * mapping)567 static inline void mapping_unmap_writable(struct address_space *mapping)
568 {
569 atomic_dec(&mapping->i_mmap_writable);
570 }
571
mapping_deny_writable(struct address_space * mapping)572 static inline int mapping_deny_writable(struct address_space *mapping)
573 {
574 return atomic_dec_unless_positive(&mapping->i_mmap_writable) ?
575 0 : -EBUSY;
576 }
577
mapping_allow_writable(struct address_space * mapping)578 static inline void mapping_allow_writable(struct address_space *mapping)
579 {
580 atomic_inc(&mapping->i_mmap_writable);
581 }
582
583 /*
584 * Use sequence counter to get consistent i_size on 32-bit processors.
585 */
586 #if BITS_PER_LONG==32 && defined(CONFIG_SMP)
587 #include <linux/seqlock.h>
588 #define __NEED_I_SIZE_ORDERED
589 #define i_size_ordered_init(inode) seqcount_init(&inode->i_size_seqcount)
590 #else
591 #define i_size_ordered_init(inode) do { } while (0)
592 #endif
593
594 struct posix_acl;
595 #define ACL_NOT_CACHED ((void *)(-1))
596 /*
597 * ACL_DONT_CACHE is for stacked filesystems, that rely on underlying fs to
598 * cache the ACL. This also means that ->get_inode_acl() can be called in RCU
599 * mode with the LOOKUP_RCU flag.
600 */
601 #define ACL_DONT_CACHE ((void *)(-3))
602
603 static inline struct posix_acl *
uncached_acl_sentinel(struct task_struct * task)604 uncached_acl_sentinel(struct task_struct *task)
605 {
606 return (void *)task + 1;
607 }
608
609 static inline bool
is_uncached_acl(struct posix_acl * acl)610 is_uncached_acl(struct posix_acl *acl)
611 {
612 return (long)acl & 1;
613 }
614
615 #define IOP_FASTPERM 0x0001
616 #define IOP_LOOKUP 0x0002
617 #define IOP_NOFOLLOW 0x0004
618 #define IOP_XATTR 0x0008
619 #define IOP_DEFAULT_READLINK 0x0010
620
621 struct fsnotify_mark_connector;
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
i_blocksize(const struct inode * node)742 static inline unsigned int i_blocksize(const struct inode *node)
743 {
744 return (1 << node->i_blkbits);
745 }
746
inode_unhashed(struct inode * inode)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 */
inode_fake_hash(struct inode * inode)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
inode_lock(struct inode * inode)789 static inline void inode_lock(struct inode *inode)
790 {
791 down_write(&inode->i_rwsem);
792 }
793
inode_unlock(struct inode * inode)794 static inline void inode_unlock(struct inode *inode)
795 {
796 up_write(&inode->i_rwsem);
797 }
798
inode_lock_shared(struct inode * inode)799 static inline void inode_lock_shared(struct inode *inode)
800 {
801 down_read(&inode->i_rwsem);
802 }
803
inode_unlock_shared(struct inode * inode)804 static inline void inode_unlock_shared(struct inode *inode)
805 {
806 up_read(&inode->i_rwsem);
807 }
808
inode_trylock(struct inode * inode)809 static inline int inode_trylock(struct inode *inode)
810 {
811 return down_write_trylock(&inode->i_rwsem);
812 }
813
inode_trylock_shared(struct inode * inode)814 static inline int inode_trylock_shared(struct inode *inode)
815 {
816 return down_read_trylock(&inode->i_rwsem);
817 }
818
inode_is_locked(struct inode * inode)819 static inline int inode_is_locked(struct inode *inode)
820 {
821 return rwsem_is_locked(&inode->i_rwsem);
822 }
823
inode_lock_nested(struct inode * inode,unsigned subclass)824 static inline void inode_lock_nested(struct inode *inode, unsigned subclass)
825 {
826 down_write_nested(&inode->i_rwsem, subclass);
827 }
828
inode_lock_shared_nested(struct inode * inode,unsigned subclass)829 static inline void inode_lock_shared_nested(struct inode *inode, unsigned subclass)
830 {
831 down_read_nested(&inode->i_rwsem, subclass);
832 }
833
filemap_invalidate_lock(struct address_space * mapping)834 static inline void filemap_invalidate_lock(struct address_space *mapping)
835 {
836 down_write(&mapping->invalidate_lock);
837 }
838
filemap_invalidate_unlock(struct address_space * mapping)839 static inline void filemap_invalidate_unlock(struct address_space *mapping)
840 {
841 up_write(&mapping->invalidate_lock);
842 }
843
filemap_invalidate_lock_shared(struct address_space * mapping)844 static inline void filemap_invalidate_lock_shared(struct address_space *mapping)
845 {
846 down_read(&mapping->invalidate_lock);
847 }
848
filemap_invalidate_trylock_shared(struct address_space * mapping)849 static inline int filemap_invalidate_trylock_shared(
850 struct address_space *mapping)
851 {
852 return down_read_trylock(&mapping->invalidate_lock);
853 }
854
filemap_invalidate_unlock_shared(struct address_space * mapping)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 */
i_size_read(const struct inode * inode)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 */
i_size_write(struct inode * inode,loff_t i_size)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
iminor(const struct inode * inode)931 static inline unsigned iminor(const struct inode *inode)
932 {
933 return MINOR(inode->i_rdev);
934 }
935
imajor(const struct inode * inode)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 */
ra_has_index(struct file_ra_state * ra,pgoff_t index)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
get_file(struct file * f)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
file_inode(const struct file * f)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 */
file_dentry(const struct file * file)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_marks 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_mark_connector __rcu *s_fsnotify_marks;
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 /*
1305 * Number of inode/mount/sb objects that are being watched, note that
1306 * inodes objects are currently double-accounted.
1307 */
1308 atomic_long_t s_fsnotify_connectors;
1309
1310 /* Read-only state of the superblock is being changed */
1311 int s_readonly_remount;
1312
1313 /* per-sb errseq_t for reporting writeback errors via syncfs */
1314 errseq_t s_wb_err;
1315
1316 /* AIO completions deferred from interrupt context */
1317 struct workqueue_struct *s_dio_done_wq;
1318 struct hlist_head s_pins;
1319
1320 /*
1321 * Owning user namespace and default context in which to
1322 * interpret filesystem uids, gids, quotas, device nodes,
1323 * xattrs and security labels.
1324 */
1325 struct user_namespace *s_user_ns;
1326
1327 /*
1328 * The list_lru structure is essentially just a pointer to a table
1329 * of per-node lru lists, each of which has its own spinlock.
1330 * There is no need to put them into separate cachelines.
1331 */
1332 struct list_lru s_dentry_lru;
1333 struct list_lru s_inode_lru;
1334 struct rcu_head rcu;
1335 struct work_struct destroy_work;
1336
1337 struct mutex s_sync_lock; /* sync serialisation lock */
1338
1339 /*
1340 * Indicates how deep in a filesystem stack this SB is
1341 */
1342 int s_stack_depth;
1343
1344 /* s_inode_list_lock protects s_inodes */
1345 spinlock_t s_inode_list_lock ____cacheline_aligned_in_smp;
1346 struct list_head s_inodes; /* all inodes */
1347
1348 spinlock_t s_inode_wblist_lock;
1349 struct list_head s_inodes_wb; /* writeback inodes */
1350 } __randomize_layout;
1351
i_user_ns(const struct inode * inode)1352 static inline struct user_namespace *i_user_ns(const struct inode *inode)
1353 {
1354 return inode->i_sb->s_user_ns;
1355 }
1356
1357 /* Helper functions so that in most cases filesystems will
1358 * not need to deal directly with kuid_t and kgid_t and can
1359 * instead deal with the raw numeric values that are stored
1360 * in the filesystem.
1361 */
i_uid_read(const struct inode * inode)1362 static inline uid_t i_uid_read(const struct inode *inode)
1363 {
1364 return from_kuid(i_user_ns(inode), inode->i_uid);
1365 }
1366
i_gid_read(const struct inode * inode)1367 static inline gid_t i_gid_read(const struct inode *inode)
1368 {
1369 return from_kgid(i_user_ns(inode), inode->i_gid);
1370 }
1371
i_uid_write(struct inode * inode,uid_t uid)1372 static inline void i_uid_write(struct inode *inode, uid_t uid)
1373 {
1374 inode->i_uid = make_kuid(i_user_ns(inode), uid);
1375 }
1376
i_gid_write(struct inode * inode,gid_t gid)1377 static inline void i_gid_write(struct inode *inode, gid_t gid)
1378 {
1379 inode->i_gid = make_kgid(i_user_ns(inode), gid);
1380 }
1381
1382 /**
1383 * i_uid_into_vfsuid - map an inode's i_uid down according to an idmapping
1384 * @idmap: idmap of the mount the inode was found from
1385 * @inode: inode to map
1386 *
1387 * Return: whe inode's i_uid mapped down according to @idmap.
1388 * If the inode's i_uid has no mapping INVALID_VFSUID is returned.
1389 */
i_uid_into_vfsuid(struct mnt_idmap * idmap,const struct inode * inode)1390 static inline vfsuid_t i_uid_into_vfsuid(struct mnt_idmap *idmap,
1391 const struct inode *inode)
1392 {
1393 return make_vfsuid(idmap, i_user_ns(inode), inode->i_uid);
1394 }
1395
1396 /**
1397 * i_uid_needs_update - check whether inode's i_uid needs to be updated
1398 * @idmap: idmap of the mount the inode was found from
1399 * @attr: the new attributes of @inode
1400 * @inode: the inode to update
1401 *
1402 * Check whether the $inode's i_uid field needs to be updated taking idmapped
1403 * mounts into account if the filesystem supports it.
1404 *
1405 * Return: true if @inode's i_uid field needs to be updated, false if not.
1406 */
i_uid_needs_update(struct mnt_idmap * idmap,const struct iattr * attr,const struct inode * inode)1407 static inline bool i_uid_needs_update(struct mnt_idmap *idmap,
1408 const struct iattr *attr,
1409 const struct inode *inode)
1410 {
1411 return ((attr->ia_valid & ATTR_UID) &&
1412 !vfsuid_eq(attr->ia_vfsuid,
1413 i_uid_into_vfsuid(idmap, inode)));
1414 }
1415
1416 /**
1417 * i_uid_update - update @inode's i_uid field
1418 * @idmap: idmap of the mount the inode was found from
1419 * @attr: the new attributes of @inode
1420 * @inode: the inode to update
1421 *
1422 * Safely update @inode's i_uid field translating the vfsuid of any idmapped
1423 * mount into the filesystem kuid.
1424 */
i_uid_update(struct mnt_idmap * idmap,const struct iattr * attr,struct inode * inode)1425 static inline void i_uid_update(struct mnt_idmap *idmap,
1426 const struct iattr *attr,
1427 struct inode *inode)
1428 {
1429 if (attr->ia_valid & ATTR_UID)
1430 inode->i_uid = from_vfsuid(idmap, i_user_ns(inode),
1431 attr->ia_vfsuid);
1432 }
1433
1434 /**
1435 * i_gid_into_vfsgid - map an inode's i_gid down according to an idmapping
1436 * @idmap: idmap of the mount the inode was found from
1437 * @inode: inode to map
1438 *
1439 * Return: the inode's i_gid mapped down according to @idmap.
1440 * If the inode's i_gid has no mapping INVALID_VFSGID is returned.
1441 */
i_gid_into_vfsgid(struct mnt_idmap * idmap,const struct inode * inode)1442 static inline vfsgid_t i_gid_into_vfsgid(struct mnt_idmap *idmap,
1443 const struct inode *inode)
1444 {
1445 return make_vfsgid(idmap, i_user_ns(inode), inode->i_gid);
1446 }
1447
1448 /**
1449 * i_gid_needs_update - check whether inode's i_gid needs to be updated
1450 * @idmap: idmap of the mount the inode was found from
1451 * @attr: the new attributes of @inode
1452 * @inode: the inode to update
1453 *
1454 * Check whether the $inode's i_gid field needs to be updated taking idmapped
1455 * mounts into account if the filesystem supports it.
1456 *
1457 * Return: true if @inode's i_gid field needs to be updated, false if not.
1458 */
i_gid_needs_update(struct mnt_idmap * idmap,const struct iattr * attr,const struct inode * inode)1459 static inline bool i_gid_needs_update(struct mnt_idmap *idmap,
1460 const struct iattr *attr,
1461 const struct inode *inode)
1462 {
1463 return ((attr->ia_valid & ATTR_GID) &&
1464 !vfsgid_eq(attr->ia_vfsgid,
1465 i_gid_into_vfsgid(idmap, inode)));
1466 }
1467
1468 /**
1469 * i_gid_update - update @inode's i_gid field
1470 * @idmap: idmap of the mount the inode was found from
1471 * @attr: the new attributes of @inode
1472 * @inode: the inode to update
1473 *
1474 * Safely update @inode's i_gid field translating the vfsgid of any idmapped
1475 * mount into the filesystem kgid.
1476 */
i_gid_update(struct mnt_idmap * idmap,const struct iattr * attr,struct inode * inode)1477 static inline void i_gid_update(struct mnt_idmap *idmap,
1478 const struct iattr *attr,
1479 struct inode *inode)
1480 {
1481 if (attr->ia_valid & ATTR_GID)
1482 inode->i_gid = from_vfsgid(idmap, i_user_ns(inode),
1483 attr->ia_vfsgid);
1484 }
1485
1486 /**
1487 * inode_fsuid_set - initialize inode's i_uid field with callers fsuid
1488 * @inode: inode to initialize
1489 * @idmap: idmap of the mount the inode was found from
1490 *
1491 * Initialize the i_uid field of @inode. If the inode was found/created via
1492 * an idmapped mount map the caller's fsuid according to @idmap.
1493 */
inode_fsuid_set(struct inode * inode,struct mnt_idmap * idmap)1494 static inline void inode_fsuid_set(struct inode *inode,
1495 struct mnt_idmap *idmap)
1496 {
1497 inode->i_uid = mapped_fsuid(idmap, i_user_ns(inode));
1498 }
1499
1500 /**
1501 * inode_fsgid_set - initialize inode's i_gid field with callers fsgid
1502 * @inode: inode to initialize
1503 * @idmap: idmap of the mount the inode was found from
1504 *
1505 * Initialize the i_gid field of @inode. If the inode was found/created via
1506 * an idmapped mount map the caller's fsgid according to @idmap.
1507 */
inode_fsgid_set(struct inode * inode,struct mnt_idmap * idmap)1508 static inline void inode_fsgid_set(struct inode *inode,
1509 struct mnt_idmap *idmap)
1510 {
1511 inode->i_gid = mapped_fsgid(idmap, i_user_ns(inode));
1512 }
1513
1514 /**
1515 * fsuidgid_has_mapping() - check whether caller's fsuid/fsgid is mapped
1516 * @sb: the superblock we want a mapping in
1517 * @idmap: idmap of the relevant mount
1518 *
1519 * Check whether the caller's fsuid and fsgid have a valid mapping in the
1520 * s_user_ns of the superblock @sb. If the caller is on an idmapped mount map
1521 * the caller's fsuid and fsgid according to the @idmap first.
1522 *
1523 * Return: true if fsuid and fsgid is mapped, false if not.
1524 */
fsuidgid_has_mapping(struct super_block * sb,struct mnt_idmap * idmap)1525 static inline bool fsuidgid_has_mapping(struct super_block *sb,
1526 struct mnt_idmap *idmap)
1527 {
1528 struct user_namespace *fs_userns = sb->s_user_ns;
1529 kuid_t kuid;
1530 kgid_t kgid;
1531
1532 kuid = mapped_fsuid(idmap, fs_userns);
1533 if (!uid_valid(kuid))
1534 return false;
1535 kgid = mapped_fsgid(idmap, fs_userns);
1536 if (!gid_valid(kgid))
1537 return false;
1538 return kuid_has_mapping(fs_userns, kuid) &&
1539 kgid_has_mapping(fs_userns, kgid);
1540 }
1541
1542 struct timespec64 current_time(struct inode *inode);
1543 struct timespec64 inode_set_ctime_current(struct inode *inode);
1544
inode_get_atime_sec(const struct inode * inode)1545 static inline time64_t inode_get_atime_sec(const struct inode *inode)
1546 {
1547 return inode->__i_atime.tv_sec;
1548 }
1549
inode_get_atime_nsec(const struct inode * inode)1550 static inline long inode_get_atime_nsec(const struct inode *inode)
1551 {
1552 return inode->__i_atime.tv_nsec;
1553 }
1554
inode_get_atime(const struct inode * inode)1555 static inline struct timespec64 inode_get_atime(const struct inode *inode)
1556 {
1557 return inode->__i_atime;
1558 }
1559
inode_set_atime_to_ts(struct inode * inode,struct timespec64 ts)1560 static inline struct timespec64 inode_set_atime_to_ts(struct inode *inode,
1561 struct timespec64 ts)
1562 {
1563 inode->__i_atime = ts;
1564 return ts;
1565 }
1566
inode_set_atime(struct inode * inode,time64_t sec,long nsec)1567 static inline struct timespec64 inode_set_atime(struct inode *inode,
1568 time64_t sec, long nsec)
1569 {
1570 struct timespec64 ts = { .tv_sec = sec,
1571 .tv_nsec = nsec };
1572 return inode_set_atime_to_ts(inode, ts);
1573 }
1574
inode_get_mtime_sec(const struct inode * inode)1575 static inline time64_t inode_get_mtime_sec(const struct inode *inode)
1576 {
1577 return inode->__i_mtime.tv_sec;
1578 }
1579
inode_get_mtime_nsec(const struct inode * inode)1580 static inline long inode_get_mtime_nsec(const struct inode *inode)
1581 {
1582 return inode->__i_mtime.tv_nsec;
1583 }
1584
inode_get_mtime(const struct inode * inode)1585 static inline struct timespec64 inode_get_mtime(const struct inode *inode)
1586 {
1587 return inode->__i_mtime;
1588 }
1589
inode_set_mtime_to_ts(struct inode * inode,struct timespec64 ts)1590 static inline struct timespec64 inode_set_mtime_to_ts(struct inode *inode,
1591 struct timespec64 ts)
1592 {
1593 inode->__i_mtime = ts;
1594 return ts;
1595 }
1596
inode_set_mtime(struct inode * inode,time64_t sec,long nsec)1597 static inline struct timespec64 inode_set_mtime(struct inode *inode,
1598 time64_t sec, long nsec)
1599 {
1600 struct timespec64 ts = { .tv_sec = sec,
1601 .tv_nsec = nsec };
1602 return inode_set_mtime_to_ts(inode, ts);
1603 }
1604
inode_get_ctime_sec(const struct inode * inode)1605 static inline time64_t inode_get_ctime_sec(const struct inode *inode)
1606 {
1607 return inode->__i_ctime.tv_sec;
1608 }
1609
inode_get_ctime_nsec(const struct inode * inode)1610 static inline long inode_get_ctime_nsec(const struct inode *inode)
1611 {
1612 return inode->__i_ctime.tv_nsec;
1613 }
1614
inode_get_ctime(const struct inode * inode)1615 static inline struct timespec64 inode_get_ctime(const struct inode *inode)
1616 {
1617 return inode->__i_ctime;
1618 }
1619
inode_set_ctime_to_ts(struct inode * inode,struct timespec64 ts)1620 static inline struct timespec64 inode_set_ctime_to_ts(struct inode *inode,
1621 struct timespec64 ts)
1622 {
1623 inode->__i_ctime = ts;
1624 return ts;
1625 }
1626
1627 /**
1628 * inode_set_ctime - set the ctime in the inode
1629 * @inode: inode in which to set the ctime
1630 * @sec: tv_sec value to set
1631 * @nsec: tv_nsec value to set
1632 *
1633 * Set the ctime in @inode to { @sec, @nsec }
1634 */
inode_set_ctime(struct inode * inode,time64_t sec,long nsec)1635 static inline struct timespec64 inode_set_ctime(struct inode *inode,
1636 time64_t sec, long nsec)
1637 {
1638 struct timespec64 ts = { .tv_sec = sec,
1639 .tv_nsec = nsec };
1640
1641 return inode_set_ctime_to_ts(inode, ts);
1642 }
1643
1644 struct timespec64 simple_inode_init_ts(struct inode *inode);
1645
1646 /*
1647 * Snapshotting support.
1648 */
1649
1650 /*
1651 * These are internal functions, please use sb_start_{write,pagefault,intwrite}
1652 * instead.
1653 */
__sb_end_write(struct super_block * sb,int level)1654 static inline void __sb_end_write(struct super_block *sb, int level)
1655 {
1656 percpu_up_read(sb->s_writers.rw_sem + level-1);
1657 }
1658
__sb_start_write(struct super_block * sb,int level)1659 static inline void __sb_start_write(struct super_block *sb, int level)
1660 {
1661 percpu_down_read(sb->s_writers.rw_sem + level - 1);
1662 }
1663
__sb_start_write_trylock(struct super_block * sb,int level)1664 static inline bool __sb_start_write_trylock(struct super_block *sb, int level)
1665 {
1666 return percpu_down_read_trylock(sb->s_writers.rw_sem + level - 1);
1667 }
1668
1669 #define __sb_writers_acquired(sb, lev) \
1670 percpu_rwsem_acquire(&(sb)->s_writers.rw_sem[(lev)-1], 1, _THIS_IP_)
1671 #define __sb_writers_release(sb, lev) \
1672 percpu_rwsem_release(&(sb)->s_writers.rw_sem[(lev)-1], 1, _THIS_IP_)
1673
1674 /**
1675 * __sb_write_started - check if sb freeze level is held
1676 * @sb: the super we write to
1677 * @level: the freeze level
1678 *
1679 * * > 0 - sb freeze level is held
1680 * * 0 - sb freeze level is not held
1681 * * < 0 - !CONFIG_LOCKDEP/LOCK_STATE_UNKNOWN
1682 */
__sb_write_started(const struct super_block * sb,int level)1683 static inline int __sb_write_started(const struct super_block *sb, int level)
1684 {
1685 return lockdep_is_held_type(sb->s_writers.rw_sem + level - 1, 1);
1686 }
1687
1688 /**
1689 * sb_write_started - check if SB_FREEZE_WRITE is held
1690 * @sb: the super we write to
1691 *
1692 * May be false positive with !CONFIG_LOCKDEP/LOCK_STATE_UNKNOWN.
1693 */
sb_write_started(const struct super_block * sb)1694 static inline bool sb_write_started(const struct super_block *sb)
1695 {
1696 return __sb_write_started(sb, SB_FREEZE_WRITE);
1697 }
1698
1699 /**
1700 * sb_write_not_started - check if SB_FREEZE_WRITE is not held
1701 * @sb: the super we write to
1702 *
1703 * May be false positive with !CONFIG_LOCKDEP/LOCK_STATE_UNKNOWN.
1704 */
sb_write_not_started(const struct super_block * sb)1705 static inline bool sb_write_not_started(const struct super_block *sb)
1706 {
1707 return __sb_write_started(sb, SB_FREEZE_WRITE) <= 0;
1708 }
1709
1710 /**
1711 * file_write_started - check if SB_FREEZE_WRITE is held
1712 * @file: the file we write to
1713 *
1714 * May be false positive with !CONFIG_LOCKDEP/LOCK_STATE_UNKNOWN.
1715 * May be false positive with !S_ISREG, because file_start_write() has
1716 * no effect on !S_ISREG.
1717 */
file_write_started(const struct file * file)1718 static inline bool file_write_started(const struct file *file)
1719 {
1720 if (!S_ISREG(file_inode(file)->i_mode))
1721 return true;
1722 return sb_write_started(file_inode(file)->i_sb);
1723 }
1724
1725 /**
1726 * file_write_not_started - check if SB_FREEZE_WRITE is not held
1727 * @file: the file we write to
1728 *
1729 * May be false positive with !CONFIG_LOCKDEP/LOCK_STATE_UNKNOWN.
1730 * May be false positive with !S_ISREG, because file_start_write() has
1731 * no effect on !S_ISREG.
1732 */
file_write_not_started(const struct file * file)1733 static inline bool file_write_not_started(const struct file *file)
1734 {
1735 if (!S_ISREG(file_inode(file)->i_mode))
1736 return true;
1737 return sb_write_not_started(file_inode(file)->i_sb);
1738 }
1739
1740 /**
1741 * sb_end_write - drop write access to a superblock
1742 * @sb: the super we wrote to
1743 *
1744 * Decrement number of writers to the filesystem. Wake up possible waiters
1745 * wanting to freeze the filesystem.
1746 */
sb_end_write(struct super_block * sb)1747 static inline void sb_end_write(struct super_block *sb)
1748 {
1749 __sb_end_write(sb, SB_FREEZE_WRITE);
1750 }
1751
1752 /**
1753 * sb_end_pagefault - drop write access to a superblock from a page fault
1754 * @sb: the super we wrote to
1755 *
1756 * Decrement number of processes handling write page fault to the filesystem.
1757 * Wake up possible waiters wanting to freeze the filesystem.
1758 */
sb_end_pagefault(struct super_block * sb)1759 static inline void sb_end_pagefault(struct super_block *sb)
1760 {
1761 __sb_end_write(sb, SB_FREEZE_PAGEFAULT);
1762 }
1763
1764 /**
1765 * sb_end_intwrite - drop write access to a superblock for internal fs purposes
1766 * @sb: the super we wrote to
1767 *
1768 * Decrement fs-internal number of writers to the filesystem. Wake up possible
1769 * waiters wanting to freeze the filesystem.
1770 */
sb_end_intwrite(struct super_block * sb)1771 static inline void sb_end_intwrite(struct super_block *sb)
1772 {
1773 __sb_end_write(sb, SB_FREEZE_FS);
1774 }
1775
1776 /**
1777 * sb_start_write - get write access to a superblock
1778 * @sb: the super we write to
1779 *
1780 * When a process wants to write data or metadata to a file system (i.e. dirty
1781 * a page or an inode), it should embed the operation in a sb_start_write() -
1782 * sb_end_write() pair to get exclusion against file system freezing. This
1783 * function increments number of writers preventing freezing. If the file
1784 * system is already frozen, the function waits until the file system is
1785 * thawed.
1786 *
1787 * Since freeze protection behaves as a lock, users have to preserve
1788 * ordering of freeze protection and other filesystem locks. Generally,
1789 * freeze protection should be the outermost lock. In particular, we have:
1790 *
1791 * sb_start_write
1792 * -> i_mutex (write path, truncate, directory ops, ...)
1793 * -> s_umount (freeze_super, thaw_super)
1794 */
sb_start_write(struct super_block * sb)1795 static inline void sb_start_write(struct super_block *sb)
1796 {
1797 __sb_start_write(sb, SB_FREEZE_WRITE);
1798 }
1799
sb_start_write_trylock(struct super_block * sb)1800 static inline bool sb_start_write_trylock(struct super_block *sb)
1801 {
1802 return __sb_start_write_trylock(sb, SB_FREEZE_WRITE);
1803 }
1804
1805 /**
1806 * sb_start_pagefault - get write access to a superblock from a page fault
1807 * @sb: the super we write to
1808 *
1809 * When a process starts handling write page fault, it should embed the
1810 * operation into sb_start_pagefault() - sb_end_pagefault() pair to get
1811 * exclusion against file system freezing. This is needed since the page fault
1812 * is going to dirty a page. This function increments number of running page
1813 * faults preventing freezing. If the file system is already frozen, the
1814 * function waits until the file system is thawed.
1815 *
1816 * Since page fault freeze protection behaves as a lock, users have to preserve
1817 * ordering of freeze protection and other filesystem locks. It is advised to
1818 * put sb_start_pagefault() close to mmap_lock in lock ordering. Page fault
1819 * handling code implies lock dependency:
1820 *
1821 * mmap_lock
1822 * -> sb_start_pagefault
1823 */
sb_start_pagefault(struct super_block * sb)1824 static inline void sb_start_pagefault(struct super_block *sb)
1825 {
1826 __sb_start_write(sb, SB_FREEZE_PAGEFAULT);
1827 }
1828
1829 /**
1830 * sb_start_intwrite - get write access to a superblock for internal fs purposes
1831 * @sb: the super we write to
1832 *
1833 * This is the third level of protection against filesystem freezing. It is
1834 * free for use by a filesystem. The only requirement is that it must rank
1835 * below sb_start_pagefault.
1836 *
1837 * For example filesystem can call sb_start_intwrite() when starting a
1838 * transaction which somewhat eases handling of freezing for internal sources
1839 * of filesystem changes (internal fs threads, discarding preallocation on file
1840 * close, etc.).
1841 */
sb_start_intwrite(struct super_block * sb)1842 static inline void sb_start_intwrite(struct super_block *sb)
1843 {
1844 __sb_start_write(sb, SB_FREEZE_FS);
1845 }
1846
sb_start_intwrite_trylock(struct super_block * sb)1847 static inline bool sb_start_intwrite_trylock(struct super_block *sb)
1848 {
1849 return __sb_start_write_trylock(sb, SB_FREEZE_FS);
1850 }
1851
1852 bool inode_owner_or_capable(struct mnt_idmap *idmap,
1853 const struct inode *inode);
1854
1855 /*
1856 * VFS helper functions..
1857 */
1858 int vfs_create(struct mnt_idmap *, struct inode *,
1859 struct dentry *, umode_t, bool);
1860 int vfs_mkdir(struct mnt_idmap *, struct inode *,
1861 struct dentry *, umode_t);
1862 int vfs_mknod(struct mnt_idmap *, struct inode *, struct dentry *,
1863 umode_t, dev_t);
1864 int vfs_symlink(struct mnt_idmap *, struct inode *,
1865 struct dentry *, const char *);
1866 int vfs_link(struct dentry *, struct mnt_idmap *, struct inode *,
1867 struct dentry *, struct inode **);
1868 int vfs_rmdir(struct mnt_idmap *, struct inode *, struct dentry *);
1869 int vfs_unlink(struct mnt_idmap *, struct inode *, struct dentry *,
1870 struct inode **);
1871
1872 /**
1873 * struct renamedata - contains all information required for renaming
1874 * @old_mnt_idmap: idmap of the old mount the inode was found from
1875 * @old_dir: parent of source
1876 * @old_dentry: source
1877 * @new_mnt_idmap: idmap of the new mount the inode was found from
1878 * @new_dir: parent of destination
1879 * @new_dentry: destination
1880 * @delegated_inode: returns an inode needing a delegation break
1881 * @flags: rename flags
1882 */
1883 struct renamedata {
1884 struct mnt_idmap *old_mnt_idmap;
1885 struct inode *old_dir;
1886 struct dentry *old_dentry;
1887 struct mnt_idmap *new_mnt_idmap;
1888 struct inode *new_dir;
1889 struct dentry *new_dentry;
1890 struct inode **delegated_inode;
1891 unsigned int flags;
1892 } __randomize_layout;
1893
1894 int vfs_rename(struct renamedata *);
1895
vfs_whiteout(struct mnt_idmap * idmap,struct inode * dir,struct dentry * dentry)1896 static inline int vfs_whiteout(struct mnt_idmap *idmap,
1897 struct inode *dir, struct dentry *dentry)
1898 {
1899 return vfs_mknod(idmap, dir, dentry, S_IFCHR | WHITEOUT_MODE,
1900 WHITEOUT_DEV);
1901 }
1902
1903 struct file *kernel_tmpfile_open(struct mnt_idmap *idmap,
1904 const struct path *parentpath,
1905 umode_t mode, int open_flag,
1906 const struct cred *cred);
1907 struct file *kernel_file_open(const struct path *path, int flags,
1908 struct inode *inode, const struct cred *cred);
1909
1910 int vfs_mkobj(struct dentry *, umode_t,
1911 int (*f)(struct dentry *, umode_t, void *),
1912 void *);
1913
1914 int vfs_fchown(struct file *file, uid_t user, gid_t group);
1915 int vfs_fchmod(struct file *file, umode_t mode);
1916 int vfs_utimes(const struct path *path, struct timespec64 *times);
1917
1918 extern long vfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
1919
1920 #ifdef CONFIG_COMPAT
1921 extern long compat_ptr_ioctl(struct file *file, unsigned int cmd,
1922 unsigned long arg);
1923 #else
1924 #define compat_ptr_ioctl NULL
1925 #endif
1926
1927 /*
1928 * VFS file helper functions.
1929 */
1930 void inode_init_owner(struct mnt_idmap *idmap, struct inode *inode,
1931 const struct inode *dir, umode_t mode);
1932 extern bool may_open_dev(const struct path *path);
1933 umode_t mode_strip_sgid(struct mnt_idmap *idmap,
1934 const struct inode *dir, umode_t mode);
1935
1936 /*
1937 * This is the "filldir" function type, used by readdir() to let
1938 * the kernel specify what kind of dirent layout it wants to have.
1939 * This allows the kernel to read directories into kernel space or
1940 * to have different dirent layouts depending on the binary type.
1941 * Return 'true' to keep going and 'false' if there are no more entries.
1942 */
1943 struct dir_context;
1944 typedef bool (*filldir_t)(struct dir_context *, const char *, int, loff_t, u64,
1945 unsigned);
1946
1947 struct dir_context {
1948 filldir_t actor;
1949 loff_t pos;
1950 };
1951
1952 /*
1953 * These flags let !MMU mmap() govern direct device mapping vs immediate
1954 * copying more easily for MAP_PRIVATE, especially for ROM filesystems.
1955 *
1956 * NOMMU_MAP_COPY: Copy can be mapped (MAP_PRIVATE)
1957 * NOMMU_MAP_DIRECT: Can be mapped directly (MAP_SHARED)
1958 * NOMMU_MAP_READ: Can be mapped for reading
1959 * NOMMU_MAP_WRITE: Can be mapped for writing
1960 * NOMMU_MAP_EXEC: Can be mapped for execution
1961 */
1962 #define NOMMU_MAP_COPY 0x00000001
1963 #define NOMMU_MAP_DIRECT 0x00000008
1964 #define NOMMU_MAP_READ VM_MAYREAD
1965 #define NOMMU_MAP_WRITE VM_MAYWRITE
1966 #define NOMMU_MAP_EXEC VM_MAYEXEC
1967
1968 #define NOMMU_VMFLAGS \
1969 (NOMMU_MAP_READ | NOMMU_MAP_WRITE | NOMMU_MAP_EXEC)
1970
1971 /*
1972 * These flags control the behavior of the remap_file_range function pointer.
1973 * If it is called with len == 0 that means "remap to end of source file".
1974 * See Documentation/filesystems/vfs.rst for more details about this call.
1975 *
1976 * REMAP_FILE_DEDUP: only remap if contents identical (i.e. deduplicate)
1977 * REMAP_FILE_CAN_SHORTEN: caller can handle a shortened request
1978 */
1979 #define REMAP_FILE_DEDUP (1 << 0)
1980 #define REMAP_FILE_CAN_SHORTEN (1 << 1)
1981
1982 /*
1983 * These flags signal that the caller is ok with altering various aspects of
1984 * the behavior of the remap operation. The changes must be made by the
1985 * implementation; the vfs remap helper functions can take advantage of them.
1986 * Flags in this category exist to preserve the quirky behavior of the hoisted
1987 * btrfs clone/dedupe ioctls.
1988 */
1989 #define REMAP_FILE_ADVISORY (REMAP_FILE_CAN_SHORTEN)
1990
1991 /*
1992 * These flags control the behavior of vfs_copy_file_range().
1993 * They are not available to the user via syscall.
1994 *
1995 * COPY_FILE_SPLICE: call splice direct instead of fs clone/copy ops
1996 */
1997 #define COPY_FILE_SPLICE (1 << 0)
1998
1999 struct iov_iter;
2000 struct io_uring_cmd;
2001 struct offset_ctx;
2002
2003 typedef unsigned int __bitwise fop_flags_t;
2004
2005 struct file_operations {
2006 struct module *owner;
2007 fop_flags_t fop_flags;
2008 loff_t (*llseek) (struct file *, loff_t, int);
2009 ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);
2010 ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
2011 ssize_t (*read_iter) (struct kiocb *, struct iov_iter *);
2012 ssize_t (*write_iter) (struct kiocb *, struct iov_iter *);
2013 int (*iopoll)(struct kiocb *kiocb, struct io_comp_batch *,
2014 unsigned int flags);
2015 int (*iterate_shared) (struct file *, struct dir_context *);
2016 __poll_t (*poll) (struct file *, struct poll_table_struct *);
2017 long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
2018 long (*compat_ioctl) (struct file *, unsigned int, unsigned long);
2019 int (*mmap) (struct file *, struct vm_area_struct *);
2020 int (*open) (struct inode *, struct file *);
2021 int (*flush) (struct file *, fl_owner_t id);
2022 int (*release) (struct inode *, struct file *);
2023 int (*fsync) (struct file *, loff_t, loff_t, int datasync);
2024 int (*fasync) (int, struct file *, int);
2025 int (*lock) (struct file *, int, struct file_lock *);
2026 unsigned long (*get_unmapped_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
2027 int (*check_flags)(int);
2028 int (*flock) (struct file *, int, struct file_lock *);
2029 ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, loff_t *, size_t, unsigned int);
2030 ssize_t (*splice_read)(struct file *, loff_t *, struct pipe_inode_info *, size_t, unsigned int);
2031 void (*splice_eof)(struct file *file);
2032 int (*setlease)(struct file *, int, struct file_lease **, void **);
2033 long (*fallocate)(struct file *file, int mode, loff_t offset,
2034 loff_t len);
2035 void (*show_fdinfo)(struct seq_file *m, struct file *f);
2036 #ifndef CONFIG_MMU
2037 unsigned (*mmap_capabilities)(struct file *);
2038 #endif
2039 ssize_t (*copy_file_range)(struct file *, loff_t, struct file *,
2040 loff_t, size_t, unsigned int);
2041 loff_t (*remap_file_range)(struct file *file_in, loff_t pos_in,
2042 struct file *file_out, loff_t pos_out,
2043 loff_t len, unsigned int remap_flags);
2044 int (*fadvise)(struct file *, loff_t, loff_t, int);
2045 int (*uring_cmd)(struct io_uring_cmd *ioucmd, unsigned int issue_flags);
2046 int (*uring_cmd_iopoll)(struct io_uring_cmd *, struct io_comp_batch *,
2047 unsigned int poll_flags);
2048 } __randomize_layout;
2049
2050 /* Supports async buffered reads */
2051 #define FOP_BUFFER_RASYNC ((__force fop_flags_t)(1 << 0))
2052 /* Supports async buffered writes */
2053 #define FOP_BUFFER_WASYNC ((__force fop_flags_t)(1 << 1))
2054 /* Supports synchronous page faults for mappings */
2055 #define FOP_MMAP_SYNC ((__force fop_flags_t)(1 << 2))
2056 /* Supports non-exclusive O_DIRECT writes from multiple threads */
2057 #define FOP_DIO_PARALLEL_WRITE ((__force fop_flags_t)(1 << 3))
2058 /* Contains huge pages */
2059 #define FOP_HUGE_PAGES ((__force fop_flags_t)(1 << 4))
2060
2061 /* Wrap a directory iterator that needs exclusive inode access */
2062 int wrap_directory_iterator(struct file *, struct dir_context *,
2063 int (*) (struct file *, struct dir_context *));
2064 #define WRAP_DIR_ITER(x) \
2065 static int shared_##x(struct file *file , struct dir_context *ctx) \
2066 { return wrap_directory_iterator(file, ctx, x); }
2067
2068 struct inode_operations {
2069 struct dentry * (*lookup) (struct inode *,struct dentry *, unsigned int);
2070 const char * (*get_link) (struct dentry *, struct inode *, struct delayed_call *);
2071 int (*permission) (struct mnt_idmap *, struct inode *, int);
2072 struct posix_acl * (*get_inode_acl)(struct inode *, int, bool);
2073
2074 int (*readlink) (struct dentry *, char __user *,int);
2075
2076 int (*create) (struct mnt_idmap *, struct inode *,struct dentry *,
2077 umode_t, bool);
2078 int (*link) (struct dentry *,struct inode *,struct dentry *);
2079 int (*unlink) (struct inode *,struct dentry *);
2080 int (*symlink) (struct mnt_idmap *, struct inode *,struct dentry *,
2081 const char *);
2082 int (*mkdir) (struct mnt_idmap *, struct inode *,struct dentry *,
2083 umode_t);
2084 int (*rmdir) (struct inode *,struct dentry *);
2085 int (*mknod) (struct mnt_idmap *, struct inode *,struct dentry *,
2086 umode_t,dev_t);
2087 int (*rename) (struct mnt_idmap *, struct inode *, struct dentry *,
2088 struct inode *, struct dentry *, unsigned int);
2089 int (*setattr) (struct mnt_idmap *, struct dentry *, struct iattr *);
2090 int (*getattr) (struct mnt_idmap *, const struct path *,
2091 struct kstat *, u32, unsigned int);
2092 ssize_t (*listxattr) (struct dentry *, char *, size_t);
2093 int (*fiemap)(struct inode *, struct fiemap_extent_info *, u64 start,
2094 u64 len);
2095 int (*update_time)(struct inode *, int);
2096 int (*atomic_open)(struct inode *, struct dentry *,
2097 struct file *, unsigned open_flag,
2098 umode_t create_mode);
2099 int (*tmpfile) (struct mnt_idmap *, struct inode *,
2100 struct file *, umode_t);
2101 struct posix_acl *(*get_acl)(struct mnt_idmap *, struct dentry *,
2102 int);
2103 int (*set_acl)(struct mnt_idmap *, struct dentry *,
2104 struct posix_acl *, int);
2105 int (*fileattr_set)(struct mnt_idmap *idmap,
2106 struct dentry *dentry, struct fileattr *fa);
2107 int (*fileattr_get)(struct dentry *dentry, struct fileattr *fa);
2108 struct offset_ctx *(*get_offset_ctx)(struct inode *inode);
2109 } ____cacheline_aligned;
2110
call_read_iter(struct file * file,struct kiocb * kio,struct iov_iter * iter)2111 static inline ssize_t call_read_iter(struct file *file, struct kiocb *kio,
2112 struct iov_iter *iter)
2113 {
2114 return file->f_op->read_iter(kio, iter);
2115 }
2116
call_write_iter(struct file * file,struct kiocb * kio,struct iov_iter * iter)2117 static inline ssize_t call_write_iter(struct file *file, struct kiocb *kio,
2118 struct iov_iter *iter)
2119 {
2120 return file->f_op->write_iter(kio, iter);
2121 }
2122
call_mmap(struct file * file,struct vm_area_struct * vma)2123 static inline int call_mmap(struct file *file, struct vm_area_struct *vma)
2124 {
2125 return file->f_op->mmap(file, vma);
2126 }
2127
2128 extern ssize_t vfs_read(struct file *, char __user *, size_t, loff_t *);
2129 extern ssize_t vfs_write(struct file *, const char __user *, size_t, loff_t *);
2130 extern ssize_t vfs_copy_file_range(struct file *, loff_t , struct file *,
2131 loff_t, size_t, unsigned int);
2132 int __generic_remap_file_range_prep(struct file *file_in, loff_t pos_in,
2133 struct file *file_out, loff_t pos_out,
2134 loff_t *len, unsigned int remap_flags,
2135 const struct iomap_ops *dax_read_ops);
2136 int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in,
2137 struct file *file_out, loff_t pos_out,
2138 loff_t *count, unsigned int remap_flags);
2139 extern loff_t vfs_clone_file_range(struct file *file_in, loff_t pos_in,
2140 struct file *file_out, loff_t pos_out,
2141 loff_t len, unsigned int remap_flags);
2142 extern int vfs_dedupe_file_range(struct file *file,
2143 struct file_dedupe_range *same);
2144 extern loff_t vfs_dedupe_file_range_one(struct file *src_file, loff_t src_pos,
2145 struct file *dst_file, loff_t dst_pos,
2146 loff_t len, unsigned int remap_flags);
2147
2148 /**
2149 * enum freeze_holder - holder of the freeze
2150 * @FREEZE_HOLDER_KERNEL: kernel wants to freeze or thaw filesystem
2151 * @FREEZE_HOLDER_USERSPACE: userspace wants to freeze or thaw filesystem
2152 * @FREEZE_MAY_NEST: whether nesting freeze and thaw requests is allowed
2153 *
2154 * Indicate who the owner of the freeze or thaw request is and whether
2155 * the freeze needs to be exclusive or can nest.
2156 * Without @FREEZE_MAY_NEST, multiple freeze and thaw requests from the
2157 * same holder aren't allowed. It is however allowed to hold a single
2158 * @FREEZE_HOLDER_USERSPACE and a single @FREEZE_HOLDER_KERNEL freeze at
2159 * the same time. This is relied upon by some filesystems during online
2160 * repair or similar.
2161 */
2162 enum freeze_holder {
2163 FREEZE_HOLDER_KERNEL = (1U << 0),
2164 FREEZE_HOLDER_USERSPACE = (1U << 1),
2165 FREEZE_MAY_NEST = (1U << 2),
2166 };
2167
2168 struct super_operations {
2169 struct inode *(*alloc_inode)(struct super_block *sb);
2170 void (*destroy_inode)(struct inode *);
2171 void (*free_inode)(struct inode *);
2172
2173 void (*dirty_inode) (struct inode *, int flags);
2174 int (*write_inode) (struct inode *, struct writeback_control *wbc);
2175 int (*drop_inode) (struct inode *);
2176 void (*evict_inode) (struct inode *);
2177 void (*put_super) (struct super_block *);
2178 int (*sync_fs)(struct super_block *sb, int wait);
2179 int (*freeze_super) (struct super_block *, enum freeze_holder who);
2180 int (*freeze_fs) (struct super_block *);
2181 int (*thaw_super) (struct super_block *, enum freeze_holder who);
2182 int (*unfreeze_fs) (struct super_block *);
2183 int (*statfs) (struct dentry *, struct kstatfs *);
2184 int (*remount_fs) (struct super_block *, int *, char *);
2185 void (*umount_begin) (struct super_block *);
2186
2187 int (*show_options)(struct seq_file *, struct dentry *);
2188 int (*show_devname)(struct seq_file *, struct dentry *);
2189 int (*show_path)(struct seq_file *, struct dentry *);
2190 int (*show_stats)(struct seq_file *, struct dentry *);
2191 #ifdef CONFIG_QUOTA
2192 ssize_t (*quota_read)(struct super_block *, int, char *, size_t, loff_t);
2193 ssize_t (*quota_write)(struct super_block *, int, const char *, size_t, loff_t);
2194 struct dquot __rcu **(*get_dquots)(struct inode *);
2195 #endif
2196 long (*nr_cached_objects)(struct super_block *,
2197 struct shrink_control *);
2198 long (*free_cached_objects)(struct super_block *,
2199 struct shrink_control *);
2200 void (*shutdown)(struct super_block *sb);
2201 };
2202
2203 /*
2204 * Inode flags - they have no relation to superblock flags now
2205 */
2206 #define S_SYNC (1 << 0) /* Writes are synced at once */
2207 #define S_NOATIME (1 << 1) /* Do not update access times */
2208 #define S_APPEND (1 << 2) /* Append-only file */
2209 #define S_IMMUTABLE (1 << 3) /* Immutable file */
2210 #define S_DEAD (1 << 4) /* removed, but still open directory */
2211 #define S_NOQUOTA (1 << 5) /* Inode is not counted to quota */
2212 #define S_DIRSYNC (1 << 6) /* Directory modifications are synchronous */
2213 #define S_NOCMTIME (1 << 7) /* Do not update file c/mtime */
2214 #define S_SWAPFILE (1 << 8) /* Do not truncate: swapon got its bmaps */
2215 #define S_PRIVATE (1 << 9) /* Inode is fs-internal */
2216 #define S_IMA (1 << 10) /* Inode has an associated IMA struct */
2217 #define S_AUTOMOUNT (1 << 11) /* Automount/referral quasi-directory */
2218 #define S_NOSEC (1 << 12) /* no suid or xattr security attributes */
2219 #ifdef CONFIG_FS_DAX
2220 #define S_DAX (1 << 13) /* Direct Access, avoiding the page cache */
2221 #else
2222 #define S_DAX 0 /* Make all the DAX code disappear */
2223 #endif
2224 #define S_ENCRYPTED (1 << 14) /* Encrypted file (using fs/crypto/) */
2225 #define S_CASEFOLD (1 << 15) /* Casefolded file */
2226 #define S_VERITY (1 << 16) /* Verity file (using fs/verity/) */
2227 #define S_KERNEL_FILE (1 << 17) /* File is in use by the kernel (eg. fs/cachefiles) */
2228
2229 /*
2230 * Note that nosuid etc flags are inode-specific: setting some file-system
2231 * flags just means all the inodes inherit those flags by default. It might be
2232 * possible to override it selectively if you really wanted to with some
2233 * ioctl() that is not currently implemented.
2234 *
2235 * Exception: SB_RDONLY is always applied to the entire file system.
2236 *
2237 * Unfortunately, it is possible to change a filesystems flags with it mounted
2238 * with files in use. This means that all of the inodes will not have their
2239 * i_flags updated. Hence, i_flags no longer inherit the superblock mount
2240 * flags, so these have to be checked separately. -- rmk@arm.uk.linux.org
2241 */
2242 #define __IS_FLG(inode, flg) ((inode)->i_sb->s_flags & (flg))
2243
sb_rdonly(const struct super_block * sb)2244 static inline bool sb_rdonly(const struct super_block *sb) { return sb->s_flags & SB_RDONLY; }
2245 #define IS_RDONLY(inode) sb_rdonly((inode)->i_sb)
2246 #define IS_SYNC(inode) (__IS_FLG(inode, SB_SYNCHRONOUS) || \
2247 ((inode)->i_flags & S_SYNC))
2248 #define IS_DIRSYNC(inode) (__IS_FLG(inode, SB_SYNCHRONOUS|SB_DIRSYNC) || \
2249 ((inode)->i_flags & (S_SYNC|S_DIRSYNC)))
2250 #define IS_MANDLOCK(inode) __IS_FLG(inode, SB_MANDLOCK)
2251 #define IS_NOATIME(inode) __IS_FLG(inode, SB_RDONLY|SB_NOATIME)
2252 #define IS_I_VERSION(inode) __IS_FLG(inode, SB_I_VERSION)
2253
2254 #define IS_NOQUOTA(inode) ((inode)->i_flags & S_NOQUOTA)
2255 #define IS_APPEND(inode) ((inode)->i_flags & S_APPEND)
2256 #define IS_IMMUTABLE(inode) ((inode)->i_flags & S_IMMUTABLE)
2257
2258 #ifdef CONFIG_FS_POSIX_ACL
2259 #define IS_POSIXACL(inode) __IS_FLG(inode, SB_POSIXACL)
2260 #else
2261 #define IS_POSIXACL(inode) 0
2262 #endif
2263
2264 #define IS_DEADDIR(inode) ((inode)->i_flags & S_DEAD)
2265 #define IS_NOCMTIME(inode) ((inode)->i_flags & S_NOCMTIME)
2266
2267 #ifdef CONFIG_SWAP
2268 #define IS_SWAPFILE(inode) ((inode)->i_flags & S_SWAPFILE)
2269 #else
2270 #define IS_SWAPFILE(inode) ((void)(inode), 0U)
2271 #endif
2272
2273 #define IS_PRIVATE(inode) ((inode)->i_flags & S_PRIVATE)
2274 #define IS_IMA(inode) ((inode)->i_flags & S_IMA)
2275 #define IS_AUTOMOUNT(inode) ((inode)->i_flags & S_AUTOMOUNT)
2276 #define IS_NOSEC(inode) ((inode)->i_flags & S_NOSEC)
2277 #define IS_DAX(inode) ((inode)->i_flags & S_DAX)
2278 #define IS_ENCRYPTED(inode) ((inode)->i_flags & S_ENCRYPTED)
2279 #define IS_CASEFOLDED(inode) ((inode)->i_flags & S_CASEFOLD)
2280 #define IS_VERITY(inode) ((inode)->i_flags & S_VERITY)
2281
2282 #define IS_WHITEOUT(inode) (S_ISCHR(inode->i_mode) && \
2283 (inode)->i_rdev == WHITEOUT_DEV)
2284
HAS_UNMAPPED_ID(struct mnt_idmap * idmap,struct inode * inode)2285 static inline bool HAS_UNMAPPED_ID(struct mnt_idmap *idmap,
2286 struct inode *inode)
2287 {
2288 return !vfsuid_valid(i_uid_into_vfsuid(idmap, inode)) ||
2289 !vfsgid_valid(i_gid_into_vfsgid(idmap, inode));
2290 }
2291
init_sync_kiocb(struct kiocb * kiocb,struct file * filp)2292 static inline void init_sync_kiocb(struct kiocb *kiocb, struct file *filp)
2293 {
2294 *kiocb = (struct kiocb) {
2295 .ki_filp = filp,
2296 .ki_flags = filp->f_iocb_flags,
2297 .ki_ioprio = get_current_ioprio(),
2298 };
2299 }
2300
kiocb_clone(struct kiocb * kiocb,struct kiocb * kiocb_src,struct file * filp)2301 static inline void kiocb_clone(struct kiocb *kiocb, struct kiocb *kiocb_src,
2302 struct file *filp)
2303 {
2304 *kiocb = (struct kiocb) {
2305 .ki_filp = filp,
2306 .ki_flags = kiocb_src->ki_flags,
2307 .ki_ioprio = kiocb_src->ki_ioprio,
2308 .ki_pos = kiocb_src->ki_pos,
2309 };
2310 }
2311
2312 /*
2313 * Inode state bits. Protected by inode->i_lock
2314 *
2315 * Four bits determine the dirty state of the inode: I_DIRTY_SYNC,
2316 * I_DIRTY_DATASYNC, I_DIRTY_PAGES, and I_DIRTY_TIME.
2317 *
2318 * Four bits define the lifetime of an inode. Initially, inodes are I_NEW,
2319 * until that flag is cleared. I_WILL_FREE, I_FREEING and I_CLEAR are set at
2320 * various stages of removing an inode.
2321 *
2322 * Two bits are used for locking and completion notification, I_NEW and I_SYNC.
2323 *
2324 * I_DIRTY_SYNC Inode is dirty, but doesn't have to be written on
2325 * fdatasync() (unless I_DIRTY_DATASYNC is also set).
2326 * Timestamp updates are the usual cause.
2327 * I_DIRTY_DATASYNC Data-related inode changes pending. We keep track of
2328 * these changes separately from I_DIRTY_SYNC so that we
2329 * don't have to write inode on fdatasync() when only
2330 * e.g. the timestamps have changed.
2331 * I_DIRTY_PAGES Inode has dirty pages. Inode itself may be clean.
2332 * I_DIRTY_TIME The inode itself has dirty timestamps, and the
2333 * lazytime mount option is enabled. We keep track of this
2334 * separately from I_DIRTY_SYNC in order to implement
2335 * lazytime. This gets cleared if I_DIRTY_INODE
2336 * (I_DIRTY_SYNC and/or I_DIRTY_DATASYNC) gets set. But
2337 * I_DIRTY_TIME can still be set if I_DIRTY_SYNC is already
2338 * in place because writeback might already be in progress
2339 * and we don't want to lose the time update
2340 * I_NEW Serves as both a mutex and completion notification.
2341 * New inodes set I_NEW. If two processes both create
2342 * the same inode, one of them will release its inode and
2343 * wait for I_NEW to be released before returning.
2344 * Inodes in I_WILL_FREE, I_FREEING or I_CLEAR state can
2345 * also cause waiting on I_NEW, without I_NEW actually
2346 * being set. find_inode() uses this to prevent returning
2347 * nearly-dead inodes.
2348 * I_WILL_FREE Must be set when calling write_inode_now() if i_count
2349 * is zero. I_FREEING must be set when I_WILL_FREE is
2350 * cleared.
2351 * I_FREEING Set when inode is about to be freed but still has dirty
2352 * pages or buffers attached or the inode itself is still
2353 * dirty.
2354 * I_CLEAR Added by clear_inode(). In this state the inode is
2355 * clean and can be destroyed. Inode keeps I_FREEING.
2356 *
2357 * Inodes that are I_WILL_FREE, I_FREEING or I_CLEAR are
2358 * prohibited for many purposes. iget() must wait for
2359 * the inode to be completely released, then create it
2360 * anew. Other functions will just ignore such inodes,
2361 * if appropriate. I_NEW is used for waiting.
2362 *
2363 * I_SYNC Writeback of inode is running. The bit is set during
2364 * data writeback, and cleared with a wakeup on the bit
2365 * address once it is done. The bit is also used to pin
2366 * the inode in memory for flusher thread.
2367 *
2368 * I_REFERENCED Marks the inode as recently references on the LRU list.
2369 *
2370 * I_DIO_WAKEUP Never set. Only used as a key for wait_on_bit().
2371 *
2372 * I_WB_SWITCH Cgroup bdi_writeback switching in progress. Used to
2373 * synchronize competing switching instances and to tell
2374 * wb stat updates to grab the i_pages lock. See
2375 * inode_switch_wbs_work_fn() for details.
2376 *
2377 * I_OVL_INUSE Used by overlayfs to get exclusive ownership on upper
2378 * and work dirs among overlayfs mounts.
2379 *
2380 * I_CREATING New object's inode in the middle of setting up.
2381 *
2382 * I_DONTCACHE Evict inode as soon as it is not used anymore.
2383 *
2384 * I_SYNC_QUEUED Inode is queued in b_io or b_more_io writeback lists.
2385 * Used to detect that mark_inode_dirty() should not move
2386 * inode between dirty lists.
2387 *
2388 * I_PINNING_FSCACHE_WB Inode is pinning an fscache object for writeback.
2389 *
2390 * Q: What is the difference between I_WILL_FREE and I_FREEING?
2391 */
2392 #define I_DIRTY_SYNC (1 << 0)
2393 #define I_DIRTY_DATASYNC (1 << 1)
2394 #define I_DIRTY_PAGES (1 << 2)
2395 #define __I_NEW 3
2396 #define I_NEW (1 << __I_NEW)
2397 #define I_WILL_FREE (1 << 4)
2398 #define I_FREEING (1 << 5)
2399 #define I_CLEAR (1 << 6)
2400 #define __I_SYNC 7
2401 #define I_SYNC (1 << __I_SYNC)
2402 #define I_REFERENCED (1 << 8)
2403 #define __I_DIO_WAKEUP 9
2404 #define I_DIO_WAKEUP (1 << __I_DIO_WAKEUP)
2405 #define I_LINKABLE (1 << 10)
2406 #define I_DIRTY_TIME (1 << 11)
2407 #define I_WB_SWITCH (1 << 13)
2408 #define I_OVL_INUSE (1 << 14)
2409 #define I_CREATING (1 << 15)
2410 #define I_DONTCACHE (1 << 16)
2411 #define I_SYNC_QUEUED (1 << 17)
2412 #define I_PINNING_NETFS_WB (1 << 18)
2413
2414 #define I_DIRTY_INODE (I_DIRTY_SYNC | I_DIRTY_DATASYNC)
2415 #define I_DIRTY (I_DIRTY_INODE | I_DIRTY_PAGES)
2416 #define I_DIRTY_ALL (I_DIRTY | I_DIRTY_TIME)
2417
2418 extern void __mark_inode_dirty(struct inode *, int);
mark_inode_dirty(struct inode * inode)2419 static inline void mark_inode_dirty(struct inode *inode)
2420 {
2421 __mark_inode_dirty(inode, I_DIRTY);
2422 }
2423
mark_inode_dirty_sync(struct inode * inode)2424 static inline void mark_inode_dirty_sync(struct inode *inode)
2425 {
2426 __mark_inode_dirty(inode, I_DIRTY_SYNC);
2427 }
2428
2429 /*
2430 * Returns true if the given inode itself only has dirty timestamps (its pages
2431 * may still be dirty) and isn't currently being allocated or freed.
2432 * Filesystems should call this if when writing an inode when lazytime is
2433 * enabled, they want to opportunistically write the timestamps of other inodes
2434 * located very nearby on-disk, e.g. in the same inode block. This returns true
2435 * if the given inode is in need of such an opportunistic update. Requires
2436 * i_lock, or at least later re-checking under i_lock.
2437 */
inode_is_dirtytime_only(struct inode * inode)2438 static inline bool inode_is_dirtytime_only(struct inode *inode)
2439 {
2440 return (inode->i_state & (I_DIRTY_TIME | I_NEW |
2441 I_FREEING | I_WILL_FREE)) == I_DIRTY_TIME;
2442 }
2443
2444 extern void inc_nlink(struct inode *inode);
2445 extern void drop_nlink(struct inode *inode);
2446 extern void clear_nlink(struct inode *inode);
2447 extern void set_nlink(struct inode *inode, unsigned int nlink);
2448
inode_inc_link_count(struct inode * inode)2449 static inline void inode_inc_link_count(struct inode *inode)
2450 {
2451 inc_nlink(inode);
2452 mark_inode_dirty(inode);
2453 }
2454
inode_dec_link_count(struct inode * inode)2455 static inline void inode_dec_link_count(struct inode *inode)
2456 {
2457 drop_nlink(inode);
2458 mark_inode_dirty(inode);
2459 }
2460
2461 enum file_time_flags {
2462 S_ATIME = 1,
2463 S_MTIME = 2,
2464 S_CTIME = 4,
2465 S_VERSION = 8,
2466 };
2467
2468 extern bool atime_needs_update(const struct path *, struct inode *);
2469 extern void touch_atime(const struct path *);
2470 int inode_update_time(struct inode *inode, int flags);
2471
file_accessed(struct file * file)2472 static inline void file_accessed(struct file *file)
2473 {
2474 if (!(file->f_flags & O_NOATIME))
2475 touch_atime(&file->f_path);
2476 }
2477
2478 extern int file_modified(struct file *file);
2479 int kiocb_modified(struct kiocb *iocb);
2480
2481 int sync_inode_metadata(struct inode *inode, int wait);
2482
2483 struct file_system_type {
2484 const char *name;
2485 int fs_flags;
2486 #define FS_REQUIRES_DEV 1
2487 #define FS_BINARY_MOUNTDATA 2
2488 #define FS_HAS_SUBTYPE 4
2489 #define FS_USERNS_MOUNT 8 /* Can be mounted by userns root */
2490 #define FS_DISALLOW_NOTIFY_PERM 16 /* Disable fanotify permission events */
2491 #define FS_ALLOW_IDMAP 32 /* FS has been updated to handle vfs idmappings. */
2492 #define FS_RENAME_DOES_D_MOVE 32768 /* FS will handle d_move() during rename() internally. */
2493 int (*init_fs_context)(struct fs_context *);
2494 const struct fs_parameter_spec *parameters;
2495 struct dentry *(*mount) (struct file_system_type *, int,
2496 const char *, void *);
2497 void (*kill_sb) (struct super_block *);
2498 struct module *owner;
2499 struct file_system_type * next;
2500 struct hlist_head fs_supers;
2501
2502 struct lock_class_key s_lock_key;
2503 struct lock_class_key s_umount_key;
2504 struct lock_class_key s_vfs_rename_key;
2505 struct lock_class_key s_writers_key[SB_FREEZE_LEVELS];
2506
2507 struct lock_class_key i_lock_key;
2508 struct lock_class_key i_mutex_key;
2509 struct lock_class_key invalidate_lock_key;
2510 struct lock_class_key i_mutex_dir_key;
2511 };
2512
2513 #define MODULE_ALIAS_FS(NAME) MODULE_ALIAS("fs-" NAME)
2514
2515 extern struct dentry *mount_bdev(struct file_system_type *fs_type,
2516 int flags, const char *dev_name, void *data,
2517 int (*fill_super)(struct super_block *, void *, int));
2518 extern struct dentry *mount_single(struct file_system_type *fs_type,
2519 int flags, void *data,
2520 int (*fill_super)(struct super_block *, void *, int));
2521 extern struct dentry *mount_nodev(struct file_system_type *fs_type,
2522 int flags, void *data,
2523 int (*fill_super)(struct super_block *, void *, int));
2524 extern struct dentry *mount_subtree(struct vfsmount *mnt, const char *path);
2525 void retire_super(struct super_block *sb);
2526 void generic_shutdown_super(struct super_block *sb);
2527 void kill_block_super(struct super_block *sb);
2528 void kill_anon_super(struct super_block *sb);
2529 void kill_litter_super(struct super_block *sb);
2530 void deactivate_super(struct super_block *sb);
2531 void deactivate_locked_super(struct super_block *sb);
2532 int set_anon_super(struct super_block *s, void *data);
2533 int set_anon_super_fc(struct super_block *s, struct fs_context *fc);
2534 int get_anon_bdev(dev_t *);
2535 void free_anon_bdev(dev_t);
2536 struct super_block *sget_fc(struct fs_context *fc,
2537 int (*test)(struct super_block *, struct fs_context *),
2538 int (*set)(struct super_block *, struct fs_context *));
2539 struct super_block *sget(struct file_system_type *type,
2540 int (*test)(struct super_block *,void *),
2541 int (*set)(struct super_block *,void *),
2542 int flags, void *data);
2543 struct super_block *sget_dev(struct fs_context *fc, dev_t dev);
2544
2545 /* Alas, no aliases. Too much hassle with bringing module.h everywhere */
2546 #define fops_get(fops) \
2547 (((fops) && try_module_get((fops)->owner) ? (fops) : NULL))
2548 #define fops_put(fops) \
2549 do { if (fops) module_put((fops)->owner); } while(0)
2550 /*
2551 * This one is to be used *ONLY* from ->open() instances.
2552 * fops must be non-NULL, pinned down *and* module dependencies
2553 * should be sufficient to pin the caller down as well.
2554 */
2555 #define replace_fops(f, fops) \
2556 do { \
2557 struct file *__file = (f); \
2558 fops_put(__file->f_op); \
2559 BUG_ON(!(__file->f_op = (fops))); \
2560 } while(0)
2561
2562 extern int register_filesystem(struct file_system_type *);
2563 extern int unregister_filesystem(struct file_system_type *);
2564 extern int vfs_statfs(const struct path *, struct kstatfs *);
2565 extern int user_statfs(const char __user *, struct kstatfs *);
2566 extern int fd_statfs(int, struct kstatfs *);
2567 int freeze_super(struct super_block *super, enum freeze_holder who);
2568 int thaw_super(struct super_block *super, enum freeze_holder who);
2569 extern __printf(2, 3)
2570 int super_setup_bdi_name(struct super_block *sb, char *fmt, ...);
2571 extern int super_setup_bdi(struct super_block *sb);
2572
super_set_uuid(struct super_block * sb,const u8 * uuid,unsigned len)2573 static inline void super_set_uuid(struct super_block *sb, const u8 *uuid, unsigned len)
2574 {
2575 if (WARN_ON(len > sizeof(sb->s_uuid)))
2576 len = sizeof(sb->s_uuid);
2577 sb->s_uuid_len = len;
2578 memcpy(&sb->s_uuid, uuid, len);
2579 }
2580
2581 /* set sb sysfs name based on sb->s_bdev */
super_set_sysfs_name_bdev(struct super_block * sb)2582 static inline void super_set_sysfs_name_bdev(struct super_block *sb)
2583 {
2584 snprintf(sb->s_sysfs_name, sizeof(sb->s_sysfs_name), "%pg", sb->s_bdev);
2585 }
2586
2587 /* set sb sysfs name based on sb->s_uuid */
super_set_sysfs_name_uuid(struct super_block * sb)2588 static inline void super_set_sysfs_name_uuid(struct super_block *sb)
2589 {
2590 WARN_ON(sb->s_uuid_len != sizeof(sb->s_uuid));
2591 snprintf(sb->s_sysfs_name, sizeof(sb->s_sysfs_name), "%pU", sb->s_uuid.b);
2592 }
2593
2594 /* set sb sysfs name based on sb->s_id */
super_set_sysfs_name_id(struct super_block * sb)2595 static inline void super_set_sysfs_name_id(struct super_block *sb)
2596 {
2597 strscpy(sb->s_sysfs_name, sb->s_id, sizeof(sb->s_sysfs_name));
2598 }
2599
2600 /* try to use something standard before you use this */
2601 __printf(2, 3)
super_set_sysfs_name_generic(struct super_block * sb,const char * fmt,...)2602 static inline void super_set_sysfs_name_generic(struct super_block *sb, const char *fmt, ...)
2603 {
2604 va_list args;
2605
2606 va_start(args, fmt);
2607 vsnprintf(sb->s_sysfs_name, sizeof(sb->s_sysfs_name), fmt, args);
2608 va_end(args);
2609 }
2610
2611 extern int current_umask(void);
2612
2613 extern void ihold(struct inode * inode);
2614 extern void iput(struct inode *);
2615 int inode_update_timestamps(struct inode *inode, int flags);
2616 int generic_update_time(struct inode *, int);
2617
2618 /* /sys/fs */
2619 extern struct kobject *fs_kobj;
2620
2621 #define MAX_RW_COUNT (INT_MAX & PAGE_MASK)
2622
2623 /* fs/open.c */
2624 struct audit_names;
2625 struct filename {
2626 const char *name; /* pointer to actual string */
2627 const __user char *uptr; /* original userland pointer */
2628 atomic_t refcnt;
2629 struct audit_names *aname;
2630 const char iname[];
2631 };
2632 static_assert(offsetof(struct filename, iname) % sizeof(long) == 0);
2633
file_mnt_idmap(const struct file * file)2634 static inline struct mnt_idmap *file_mnt_idmap(const struct file *file)
2635 {
2636 return mnt_idmap(file->f_path.mnt);
2637 }
2638
2639 /**
2640 * is_idmapped_mnt - check whether a mount is mapped
2641 * @mnt: the mount to check
2642 *
2643 * If @mnt has an non @nop_mnt_idmap attached to it then @mnt is mapped.
2644 *
2645 * Return: true if mount is mapped, false if not.
2646 */
is_idmapped_mnt(const struct vfsmount * mnt)2647 static inline bool is_idmapped_mnt(const struct vfsmount *mnt)
2648 {
2649 return mnt_idmap(mnt) != &nop_mnt_idmap;
2650 }
2651
2652 extern long vfs_truncate(const struct path *, loff_t);
2653 int do_truncate(struct mnt_idmap *, struct dentry *, loff_t start,
2654 unsigned int time_attrs, struct file *filp);
2655 extern int vfs_fallocate(struct file *file, int mode, loff_t offset,
2656 loff_t len);
2657 extern long do_sys_open(int dfd, const char __user *filename, int flags,
2658 umode_t mode);
2659 extern struct file *file_open_name(struct filename *, int, umode_t);
2660 extern struct file *filp_open(const char *, int, umode_t);
2661 extern struct file *file_open_root(const struct path *,
2662 const char *, int, umode_t);
file_open_root_mnt(struct vfsmount * mnt,const char * name,int flags,umode_t mode)2663 static inline struct file *file_open_root_mnt(struct vfsmount *mnt,
2664 const char *name, int flags, umode_t mode)
2665 {
2666 return file_open_root(&(struct path){.mnt = mnt, .dentry = mnt->mnt_root},
2667 name, flags, mode);
2668 }
2669 struct file *dentry_open(const struct path *path, int flags,
2670 const struct cred *creds);
2671 struct file *dentry_create(const struct path *path, int flags, umode_t mode,
2672 const struct cred *cred);
2673 struct path *backing_file_user_path(struct file *f);
2674
2675 /*
2676 * When mmapping a file on a stackable filesystem (e.g., overlayfs), the file
2677 * stored in ->vm_file is a backing file whose f_inode is on the underlying
2678 * filesystem. When the mapped file path and inode number are displayed to
2679 * user (e.g. via /proc/<pid>/maps), these helpers should be used to get the
2680 * path and inode number to display to the user, which is the path of the fd
2681 * that user has requested to map and the inode number that would be returned
2682 * by fstat() on that same fd.
2683 */
2684 /* Get the path to display in /proc/<pid>/maps */
file_user_path(struct file * f)2685 static inline const struct path *file_user_path(struct file *f)
2686 {
2687 if (unlikely(f->f_mode & FMODE_BACKING))
2688 return backing_file_user_path(f);
2689 return &f->f_path;
2690 }
2691 /* Get the inode whose inode number to display in /proc/<pid>/maps */
file_user_inode(struct file * f)2692 static inline const struct inode *file_user_inode(struct file *f)
2693 {
2694 if (unlikely(f->f_mode & FMODE_BACKING))
2695 return d_inode(backing_file_user_path(f)->dentry);
2696 return file_inode(f);
2697 }
2698
file_clone_open(struct file * file)2699 static inline struct file *file_clone_open(struct file *file)
2700 {
2701 return dentry_open(&file->f_path, file->f_flags, file->f_cred);
2702 }
2703 extern int filp_close(struct file *, fl_owner_t id);
2704
2705 extern struct filename *getname_flags(const char __user *, int, int *);
2706 extern struct filename *getname_uflags(const char __user *, int);
2707 extern struct filename *getname(const char __user *);
2708 extern struct filename *getname_kernel(const char *);
2709 extern void putname(struct filename *name);
2710
2711 extern int finish_open(struct file *file, struct dentry *dentry,
2712 int (*open)(struct inode *, struct file *));
2713 extern int finish_no_open(struct file *file, struct dentry *dentry);
2714
2715 /* Helper for the simple case when original dentry is used */
finish_open_simple(struct file * file,int error)2716 static inline int finish_open_simple(struct file *file, int error)
2717 {
2718 if (error)
2719 return error;
2720
2721 return finish_open(file, file->f_path.dentry, NULL);
2722 }
2723
2724 /* fs/dcache.c */
2725 extern void __init vfs_caches_init_early(void);
2726 extern void __init vfs_caches_init(void);
2727
2728 extern struct kmem_cache *names_cachep;
2729
2730 #define __getname() kmem_cache_alloc(names_cachep, GFP_KERNEL)
2731 #define __putname(name) kmem_cache_free(names_cachep, (void *)(name))
2732
2733 extern struct super_block *blockdev_superblock;
sb_is_blkdev_sb(struct super_block * sb)2734 static inline bool sb_is_blkdev_sb(struct super_block *sb)
2735 {
2736 return IS_ENABLED(CONFIG_BLOCK) && sb == blockdev_superblock;
2737 }
2738
2739 void emergency_thaw_all(void);
2740 extern int sync_filesystem(struct super_block *);
2741 extern const struct file_operations def_blk_fops;
2742 extern const struct file_operations def_chr_fops;
2743
2744 /* fs/char_dev.c */
2745 #define CHRDEV_MAJOR_MAX 512
2746 /* Marks the bottom of the first segment of free char majors */
2747 #define CHRDEV_MAJOR_DYN_END 234
2748 /* Marks the top and bottom of the second segment of free char majors */
2749 #define CHRDEV_MAJOR_DYN_EXT_START 511
2750 #define CHRDEV_MAJOR_DYN_EXT_END 384
2751
2752 extern int alloc_chrdev_region(dev_t *, unsigned, unsigned, const char *);
2753 extern int register_chrdev_region(dev_t, unsigned, const char *);
2754 extern int __register_chrdev(unsigned int major, unsigned int baseminor,
2755 unsigned int count, const char *name,
2756 const struct file_operations *fops);
2757 extern void __unregister_chrdev(unsigned int major, unsigned int baseminor,
2758 unsigned int count, const char *name);
2759 extern void unregister_chrdev_region(dev_t, unsigned);
2760 extern void chrdev_show(struct seq_file *,off_t);
2761
register_chrdev(unsigned int major,const char * name,const struct file_operations * fops)2762 static inline int register_chrdev(unsigned int major, const char *name,
2763 const struct file_operations *fops)
2764 {
2765 return __register_chrdev(major, 0, 256, name, fops);
2766 }
2767
unregister_chrdev(unsigned int major,const char * name)2768 static inline void unregister_chrdev(unsigned int major, const char *name)
2769 {
2770 __unregister_chrdev(major, 0, 256, name);
2771 }
2772
2773 extern void init_special_inode(struct inode *, umode_t, dev_t);
2774
2775 /* Invalid inode operations -- fs/bad_inode.c */
2776 extern void make_bad_inode(struct inode *);
2777 extern bool is_bad_inode(struct inode *);
2778
2779 extern int __must_check file_fdatawait_range(struct file *file, loff_t lstart,
2780 loff_t lend);
2781 extern int __must_check file_check_and_advance_wb_err(struct file *file);
2782 extern int __must_check file_write_and_wait_range(struct file *file,
2783 loff_t start, loff_t end);
2784
file_write_and_wait(struct file * file)2785 static inline int file_write_and_wait(struct file *file)
2786 {
2787 return file_write_and_wait_range(file, 0, LLONG_MAX);
2788 }
2789
2790 extern int vfs_fsync_range(struct file *file, loff_t start, loff_t end,
2791 int datasync);
2792 extern int vfs_fsync(struct file *file, int datasync);
2793
2794 extern int sync_file_range(struct file *file, loff_t offset, loff_t nbytes,
2795 unsigned int flags);
2796
iocb_is_dsync(const struct kiocb * iocb)2797 static inline bool iocb_is_dsync(const struct kiocb *iocb)
2798 {
2799 return (iocb->ki_flags & IOCB_DSYNC) ||
2800 IS_SYNC(iocb->ki_filp->f_mapping->host);
2801 }
2802
2803 /*
2804 * Sync the bytes written if this was a synchronous write. Expect ki_pos
2805 * to already be updated for the write, and will return either the amount
2806 * of bytes passed in, or an error if syncing the file failed.
2807 */
generic_write_sync(struct kiocb * iocb,ssize_t count)2808 static inline ssize_t generic_write_sync(struct kiocb *iocb, ssize_t count)
2809 {
2810 if (iocb_is_dsync(iocb)) {
2811 int ret = vfs_fsync_range(iocb->ki_filp,
2812 iocb->ki_pos - count, iocb->ki_pos - 1,
2813 (iocb->ki_flags & IOCB_SYNC) ? 0 : 1);
2814 if (ret)
2815 return ret;
2816 }
2817
2818 return count;
2819 }
2820
2821 extern void emergency_sync(void);
2822 extern void emergency_remount(void);
2823
2824 #ifdef CONFIG_BLOCK
2825 extern int bmap(struct inode *inode, sector_t *block);
2826 #else
bmap(struct inode * inode,sector_t * block)2827 static inline int bmap(struct inode *inode, sector_t *block)
2828 {
2829 return -EINVAL;
2830 }
2831 #endif
2832
2833 int notify_change(struct mnt_idmap *, struct dentry *,
2834 struct iattr *, struct inode **);
2835 int inode_permission(struct mnt_idmap *, struct inode *, int);
2836 int generic_permission(struct mnt_idmap *, struct inode *, int);
file_permission(struct file * file,int mask)2837 static inline int file_permission(struct file *file, int mask)
2838 {
2839 return inode_permission(file_mnt_idmap(file),
2840 file_inode(file), mask);
2841 }
path_permission(const struct path * path,int mask)2842 static inline int path_permission(const struct path *path, int mask)
2843 {
2844 return inode_permission(mnt_idmap(path->mnt),
2845 d_inode(path->dentry), mask);
2846 }
2847 int __check_sticky(struct mnt_idmap *idmap, struct inode *dir,
2848 struct inode *inode);
2849
execute_ok(struct inode * inode)2850 static inline bool execute_ok(struct inode *inode)
2851 {
2852 return (inode->i_mode & S_IXUGO) || S_ISDIR(inode->i_mode);
2853 }
2854
inode_wrong_type(const struct inode * inode,umode_t mode)2855 static inline bool inode_wrong_type(const struct inode *inode, umode_t mode)
2856 {
2857 return (inode->i_mode ^ mode) & S_IFMT;
2858 }
2859
2860 /**
2861 * file_start_write - get write access to a superblock for regular file io
2862 * @file: the file we want to write to
2863 *
2864 * This is a variant of sb_start_write() which is a noop on non-regualr file.
2865 * Should be matched with a call to file_end_write().
2866 */
file_start_write(struct file * file)2867 static inline void file_start_write(struct file *file)
2868 {
2869 if (!S_ISREG(file_inode(file)->i_mode))
2870 return;
2871 sb_start_write(file_inode(file)->i_sb);
2872 }
2873
file_start_write_trylock(struct file * file)2874 static inline bool file_start_write_trylock(struct file *file)
2875 {
2876 if (!S_ISREG(file_inode(file)->i_mode))
2877 return true;
2878 return sb_start_write_trylock(file_inode(file)->i_sb);
2879 }
2880
2881 /**
2882 * file_end_write - drop write access to a superblock of a regular file
2883 * @file: the file we wrote to
2884 *
2885 * Should be matched with a call to file_start_write().
2886 */
file_end_write(struct file * file)2887 static inline void file_end_write(struct file *file)
2888 {
2889 if (!S_ISREG(file_inode(file)->i_mode))
2890 return;
2891 sb_end_write(file_inode(file)->i_sb);
2892 }
2893
2894 /**
2895 * kiocb_start_write - get write access to a superblock for async file io
2896 * @iocb: the io context we want to submit the write with
2897 *
2898 * This is a variant of sb_start_write() for async io submission.
2899 * Should be matched with a call to kiocb_end_write().
2900 */
kiocb_start_write(struct kiocb * iocb)2901 static inline void kiocb_start_write(struct kiocb *iocb)
2902 {
2903 struct inode *inode = file_inode(iocb->ki_filp);
2904
2905 sb_start_write(inode->i_sb);
2906 /*
2907 * Fool lockdep by telling it the lock got released so that it
2908 * doesn't complain about the held lock when we return to userspace.
2909 */
2910 __sb_writers_release(inode->i_sb, SB_FREEZE_WRITE);
2911 }
2912
2913 /**
2914 * kiocb_end_write - drop write access to a superblock after async file io
2915 * @iocb: the io context we sumbitted the write with
2916 *
2917 * Should be matched with a call to kiocb_start_write().
2918 */
kiocb_end_write(struct kiocb * iocb)2919 static inline void kiocb_end_write(struct kiocb *iocb)
2920 {
2921 struct inode *inode = file_inode(iocb->ki_filp);
2922
2923 /*
2924 * Tell lockdep we inherited freeze protection from submission thread.
2925 */
2926 __sb_writers_acquired(inode->i_sb, SB_FREEZE_WRITE);
2927 sb_end_write(inode->i_sb);
2928 }
2929
2930 /*
2931 * This is used for regular files where some users -- especially the
2932 * currently executed binary in a process, previously handled via
2933 * VM_DENYWRITE -- cannot handle concurrent write (and maybe mmap
2934 * read-write shared) accesses.
2935 *
2936 * get_write_access() gets write permission for a file.
2937 * put_write_access() releases this write permission.
2938 * deny_write_access() denies write access to a file.
2939 * allow_write_access() re-enables write access to a file.
2940 *
2941 * The i_writecount field of an inode can have the following values:
2942 * 0: no write access, no denied write access
2943 * < 0: (-i_writecount) users that denied write access to the file.
2944 * > 0: (i_writecount) users that have write access to the file.
2945 *
2946 * Normally we operate on that counter with atomic_{inc,dec} and it's safe
2947 * except for the cases where we don't hold i_writecount yet. Then we need to
2948 * use {get,deny}_write_access() - these functions check the sign and refuse
2949 * to do the change if sign is wrong.
2950 */
get_write_access(struct inode * inode)2951 static inline int get_write_access(struct inode *inode)
2952 {
2953 return atomic_inc_unless_negative(&inode->i_writecount) ? 0 : -ETXTBSY;
2954 }
deny_write_access(struct file * file)2955 static inline int deny_write_access(struct file *file)
2956 {
2957 struct inode *inode = file_inode(file);
2958 return atomic_dec_unless_positive(&inode->i_writecount) ? 0 : -ETXTBSY;
2959 }
put_write_access(struct inode * inode)2960 static inline void put_write_access(struct inode * inode)
2961 {
2962 atomic_dec(&inode->i_writecount);
2963 }
allow_write_access(struct file * file)2964 static inline void allow_write_access(struct file *file)
2965 {
2966 if (file)
2967 atomic_inc(&file_inode(file)->i_writecount);
2968 }
inode_is_open_for_write(const struct inode * inode)2969 static inline bool inode_is_open_for_write(const struct inode *inode)
2970 {
2971 return atomic_read(&inode->i_writecount) > 0;
2972 }
2973
2974 #if defined(CONFIG_IMA) || defined(CONFIG_FILE_LOCKING)
i_readcount_dec(struct inode * inode)2975 static inline void i_readcount_dec(struct inode *inode)
2976 {
2977 BUG_ON(atomic_dec_return(&inode->i_readcount) < 0);
2978 }
i_readcount_inc(struct inode * inode)2979 static inline void i_readcount_inc(struct inode *inode)
2980 {
2981 atomic_inc(&inode->i_readcount);
2982 }
2983 #else
i_readcount_dec(struct inode * inode)2984 static inline void i_readcount_dec(struct inode *inode)
2985 {
2986 return;
2987 }
i_readcount_inc(struct inode * inode)2988 static inline void i_readcount_inc(struct inode *inode)
2989 {
2990 return;
2991 }
2992 #endif
2993 extern int do_pipe_flags(int *, int);
2994
2995 extern ssize_t kernel_read(struct file *, void *, size_t, loff_t *);
2996 ssize_t __kernel_read(struct file *file, void *buf, size_t count, loff_t *pos);
2997 extern ssize_t kernel_write(struct file *, const void *, size_t, loff_t *);
2998 extern ssize_t __kernel_write(struct file *, const void *, size_t, loff_t *);
2999 extern struct file * open_exec(const char *);
3000
3001 /* fs/dcache.c -- generic fs support functions */
3002 extern bool is_subdir(struct dentry *, struct dentry *);
3003 extern bool path_is_under(const struct path *, const struct path *);
3004
3005 extern char *file_path(struct file *, char *, int);
3006
3007 /**
3008 * is_dot_dotdot - returns true only if @name is "." or ".."
3009 * @name: file name to check
3010 * @len: length of file name, in bytes
3011 */
is_dot_dotdot(const char * name,size_t len)3012 static inline bool is_dot_dotdot(const char *name, size_t len)
3013 {
3014 return len && unlikely(name[0] == '.') &&
3015 (len == 1 || (len == 2 && name[1] == '.'));
3016 }
3017
3018 #include <linux/err.h>
3019
3020 /* needed for stackable file system support */
3021 extern loff_t default_llseek(struct file *file, loff_t offset, int whence);
3022
3023 extern loff_t vfs_llseek(struct file *file, loff_t offset, int whence);
3024
3025 extern int inode_init_always(struct super_block *, struct inode *);
3026 extern void inode_init_once(struct inode *);
3027 extern void address_space_init_once(struct address_space *mapping);
3028 extern struct inode * igrab(struct inode *);
3029 extern ino_t iunique(struct super_block *, ino_t);
3030 extern int inode_needs_sync(struct inode *inode);
3031 extern int generic_delete_inode(struct inode *inode);
generic_drop_inode(struct inode * inode)3032 static inline int generic_drop_inode(struct inode *inode)
3033 {
3034 return !inode->i_nlink || inode_unhashed(inode);
3035 }
3036 extern void d_mark_dontcache(struct inode *inode);
3037
3038 extern struct inode *ilookup5_nowait(struct super_block *sb,
3039 unsigned long hashval, int (*test)(struct inode *, void *),
3040 void *data);
3041 extern struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
3042 int (*test)(struct inode *, void *), void *data);
3043 extern struct inode *ilookup(struct super_block *sb, unsigned long ino);
3044
3045 extern struct inode *inode_insert5(struct inode *inode, unsigned long hashval,
3046 int (*test)(struct inode *, void *),
3047 int (*set)(struct inode *, void *),
3048 void *data);
3049 extern struct inode * iget5_locked(struct super_block *, unsigned long, int (*test)(struct inode *, void *), int (*set)(struct inode *, void *), void *);
3050 extern struct inode * iget_locked(struct super_block *, unsigned long);
3051 extern struct inode *find_inode_nowait(struct super_block *,
3052 unsigned long,
3053 int (*match)(struct inode *,
3054 unsigned long, void *),
3055 void *data);
3056 extern struct inode *find_inode_rcu(struct super_block *, unsigned long,
3057 int (*)(struct inode *, void *), void *);
3058 extern struct inode *find_inode_by_ino_rcu(struct super_block *, unsigned long);
3059 extern int insert_inode_locked4(struct inode *, unsigned long, int (*test)(struct inode *, void *), void *);
3060 extern int insert_inode_locked(struct inode *);
3061 #ifdef CONFIG_DEBUG_LOCK_ALLOC
3062 extern void lockdep_annotate_inode_mutex_key(struct inode *inode);
3063 #else
lockdep_annotate_inode_mutex_key(struct inode * inode)3064 static inline void lockdep_annotate_inode_mutex_key(struct inode *inode) { };
3065 #endif
3066 extern void unlock_new_inode(struct inode *);
3067 extern void discard_new_inode(struct inode *);
3068 extern unsigned int get_next_ino(void);
3069 extern void evict_inodes(struct super_block *sb);
3070 void dump_mapping(const struct address_space *);
3071
3072 /*
3073 * Userspace may rely on the inode number being non-zero. For example, glibc
3074 * simply ignores files with zero i_ino in unlink() and other places.
3075 *
3076 * As an additional complication, if userspace was compiled with
3077 * _FILE_OFFSET_BITS=32 on a 64-bit kernel we'll only end up reading out the
3078 * lower 32 bits, so we need to check that those aren't zero explicitly. With
3079 * _FILE_OFFSET_BITS=64, this may cause some harmless false-negatives, but
3080 * better safe than sorry.
3081 */
is_zero_ino(ino_t ino)3082 static inline bool is_zero_ino(ino_t ino)
3083 {
3084 return (u32)ino == 0;
3085 }
3086
3087 extern void __iget(struct inode * inode);
3088 extern void iget_failed(struct inode *);
3089 extern void clear_inode(struct inode *);
3090 extern void __destroy_inode(struct inode *);
3091 extern struct inode *new_inode_pseudo(struct super_block *sb);
3092 extern struct inode *new_inode(struct super_block *sb);
3093 extern void free_inode_nonrcu(struct inode *inode);
3094 extern int setattr_should_drop_suidgid(struct mnt_idmap *, struct inode *);
3095 extern int file_remove_privs_flags(struct file *file, unsigned int flags);
3096 extern int file_remove_privs(struct file *);
3097 int setattr_should_drop_sgid(struct mnt_idmap *idmap,
3098 const struct inode *inode);
3099
3100 /*
3101 * This must be used for allocating filesystems specific inodes to set
3102 * up the inode reclaim context correctly.
3103 */
3104 static inline void *
alloc_inode_sb(struct super_block * sb,struct kmem_cache * cache,gfp_t gfp)3105 alloc_inode_sb(struct super_block *sb, struct kmem_cache *cache, gfp_t gfp)
3106 {
3107 return kmem_cache_alloc_lru(cache, &sb->s_inode_lru, gfp);
3108 }
3109
3110 extern void __insert_inode_hash(struct inode *, unsigned long hashval);
insert_inode_hash(struct inode * inode)3111 static inline void insert_inode_hash(struct inode *inode)
3112 {
3113 __insert_inode_hash(inode, inode->i_ino);
3114 }
3115
3116 extern void __remove_inode_hash(struct inode *);
remove_inode_hash(struct inode * inode)3117 static inline void remove_inode_hash(struct inode *inode)
3118 {
3119 if (!inode_unhashed(inode) && !hlist_fake(&inode->i_hash))
3120 __remove_inode_hash(inode);
3121 }
3122
3123 extern void inode_sb_list_add(struct inode *inode);
3124 extern void inode_add_lru(struct inode *inode);
3125
3126 extern int sb_set_blocksize(struct super_block *, int);
3127 extern int sb_min_blocksize(struct super_block *, int);
3128
3129 extern int generic_file_mmap(struct file *, struct vm_area_struct *);
3130 extern int generic_file_readonly_mmap(struct file *, struct vm_area_struct *);
3131 extern ssize_t generic_write_checks(struct kiocb *, struct iov_iter *);
3132 int generic_write_checks_count(struct kiocb *iocb, loff_t *count);
3133 extern int generic_write_check_limits(struct file *file, loff_t pos,
3134 loff_t *count);
3135 extern int generic_file_rw_checks(struct file *file_in, struct file *file_out);
3136 ssize_t filemap_read(struct kiocb *iocb, struct iov_iter *to,
3137 ssize_t already_read);
3138 extern ssize_t generic_file_read_iter(struct kiocb *, struct iov_iter *);
3139 extern ssize_t __generic_file_write_iter(struct kiocb *, struct iov_iter *);
3140 extern ssize_t generic_file_write_iter(struct kiocb *, struct iov_iter *);
3141 extern ssize_t generic_file_direct_write(struct kiocb *, struct iov_iter *);
3142 ssize_t generic_perform_write(struct kiocb *, struct iov_iter *);
3143 ssize_t direct_write_fallback(struct kiocb *iocb, struct iov_iter *iter,
3144 ssize_t direct_written, ssize_t buffered_written);
3145
3146 ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos,
3147 rwf_t flags);
3148 ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos,
3149 rwf_t flags);
3150 ssize_t vfs_iocb_iter_read(struct file *file, struct kiocb *iocb,
3151 struct iov_iter *iter);
3152 ssize_t vfs_iocb_iter_write(struct file *file, struct kiocb *iocb,
3153 struct iov_iter *iter);
3154
3155 /* fs/splice.c */
3156 ssize_t filemap_splice_read(struct file *in, loff_t *ppos,
3157 struct pipe_inode_info *pipe,
3158 size_t len, unsigned int flags);
3159 ssize_t copy_splice_read(struct file *in, loff_t *ppos,
3160 struct pipe_inode_info *pipe,
3161 size_t len, unsigned int flags);
3162 extern ssize_t iter_file_splice_write(struct pipe_inode_info *,
3163 struct file *, loff_t *, size_t, unsigned int);
3164
3165
3166 extern void
3167 file_ra_state_init(struct file_ra_state *ra, struct address_space *mapping);
3168 extern loff_t noop_llseek(struct file *file, loff_t offset, int whence);
3169 #define no_llseek NULL
3170 extern loff_t vfs_setpos(struct file *file, loff_t offset, loff_t maxsize);
3171 extern loff_t generic_file_llseek(struct file *file, loff_t offset, int whence);
3172 extern loff_t generic_file_llseek_size(struct file *file, loff_t offset,
3173 int whence, loff_t maxsize, loff_t eof);
3174 extern loff_t fixed_size_llseek(struct file *file, loff_t offset,
3175 int whence, loff_t size);
3176 extern loff_t no_seek_end_llseek_size(struct file *, loff_t, int, loff_t);
3177 extern loff_t no_seek_end_llseek(struct file *, loff_t, int);
3178 int rw_verify_area(int, struct file *, const loff_t *, size_t);
3179 extern int generic_file_open(struct inode * inode, struct file * filp);
3180 extern int nonseekable_open(struct inode * inode, struct file * filp);
3181 extern int stream_open(struct inode * inode, struct file * filp);
3182
3183 #ifdef CONFIG_BLOCK
3184 typedef void (dio_submit_t)(struct bio *bio, struct inode *inode,
3185 loff_t file_offset);
3186
3187 enum {
3188 /* need locking between buffered and direct access */
3189 DIO_LOCKING = 0x01,
3190
3191 /* filesystem does not support filling holes */
3192 DIO_SKIP_HOLES = 0x02,
3193 };
3194
3195 ssize_t __blockdev_direct_IO(struct kiocb *iocb, struct inode *inode,
3196 struct block_device *bdev, struct iov_iter *iter,
3197 get_block_t get_block,
3198 dio_iodone_t end_io,
3199 int flags);
3200
blockdev_direct_IO(struct kiocb * iocb,struct inode * inode,struct iov_iter * iter,get_block_t get_block)3201 static inline ssize_t blockdev_direct_IO(struct kiocb *iocb,
3202 struct inode *inode,
3203 struct iov_iter *iter,
3204 get_block_t get_block)
3205 {
3206 return __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev, iter,
3207 get_block, NULL, DIO_LOCKING | DIO_SKIP_HOLES);
3208 }
3209 #endif
3210
3211 void inode_dio_wait(struct inode *inode);
3212
3213 /**
3214 * inode_dio_begin - signal start of a direct I/O requests
3215 * @inode: inode the direct I/O happens on
3216 *
3217 * This is called once we've finished processing a direct I/O request,
3218 * and is used to wake up callers waiting for direct I/O to be quiesced.
3219 */
inode_dio_begin(struct inode * inode)3220 static inline void inode_dio_begin(struct inode *inode)
3221 {
3222 atomic_inc(&inode->i_dio_count);
3223 }
3224
3225 /**
3226 * inode_dio_end - signal finish of a direct I/O requests
3227 * @inode: inode the direct I/O happens on
3228 *
3229 * This is called once we've finished processing a direct I/O request,
3230 * and is used to wake up callers waiting for direct I/O to be quiesced.
3231 */
inode_dio_end(struct inode * inode)3232 static inline void inode_dio_end(struct inode *inode)
3233 {
3234 if (atomic_dec_and_test(&inode->i_dio_count))
3235 wake_up_bit(&inode->i_state, __I_DIO_WAKEUP);
3236 }
3237
3238 extern void inode_set_flags(struct inode *inode, unsigned int flags,
3239 unsigned int mask);
3240
3241 extern const struct file_operations generic_ro_fops;
3242
3243 #define special_file(m) (S_ISCHR(m)||S_ISBLK(m)||S_ISFIFO(m)||S_ISSOCK(m))
3244
3245 extern int readlink_copy(char __user *, int, const char *);
3246 extern int page_readlink(struct dentry *, char __user *, int);
3247 extern const char *page_get_link(struct dentry *, struct inode *,
3248 struct delayed_call *);
3249 extern void page_put_link(void *);
3250 extern int page_symlink(struct inode *inode, const char *symname, int len);
3251 extern const struct inode_operations page_symlink_inode_operations;
3252 extern void kfree_link(void *);
3253 void generic_fillattr(struct mnt_idmap *, u32, struct inode *, struct kstat *);
3254 void generic_fill_statx_attr(struct inode *inode, struct kstat *stat);
3255 extern int vfs_getattr_nosec(const struct path *, struct kstat *, u32, unsigned int);
3256 extern int vfs_getattr(const struct path *, struct kstat *, u32, unsigned int);
3257 void __inode_add_bytes(struct inode *inode, loff_t bytes);
3258 void inode_add_bytes(struct inode *inode, loff_t bytes);
3259 void __inode_sub_bytes(struct inode *inode, loff_t bytes);
3260 void inode_sub_bytes(struct inode *inode, loff_t bytes);
__inode_get_bytes(struct inode * inode)3261 static inline loff_t __inode_get_bytes(struct inode *inode)
3262 {
3263 return (((loff_t)inode->i_blocks) << 9) + inode->i_bytes;
3264 }
3265 loff_t inode_get_bytes(struct inode *inode);
3266 void inode_set_bytes(struct inode *inode, loff_t bytes);
3267 const char *simple_get_link(struct dentry *, struct inode *,
3268 struct delayed_call *);
3269 extern const struct inode_operations simple_symlink_inode_operations;
3270
3271 extern int iterate_dir(struct file *, struct dir_context *);
3272
3273 int vfs_fstatat(int dfd, const char __user *filename, struct kstat *stat,
3274 int flags);
3275 int vfs_fstat(int fd, struct kstat *stat);
3276
vfs_stat(const char __user * filename,struct kstat * stat)3277 static inline int vfs_stat(const char __user *filename, struct kstat *stat)
3278 {
3279 return vfs_fstatat(AT_FDCWD, filename, stat, 0);
3280 }
vfs_lstat(const char __user * name,struct kstat * stat)3281 static inline int vfs_lstat(const char __user *name, struct kstat *stat)
3282 {
3283 return vfs_fstatat(AT_FDCWD, name, stat, AT_SYMLINK_NOFOLLOW);
3284 }
3285
3286 extern const char *vfs_get_link(struct dentry *, struct delayed_call *);
3287 extern int vfs_readlink(struct dentry *, char __user *, int);
3288
3289 extern struct file_system_type *get_filesystem(struct file_system_type *fs);
3290 extern void put_filesystem(struct file_system_type *fs);
3291 extern struct file_system_type *get_fs_type(const char *name);
3292 extern void drop_super(struct super_block *sb);
3293 extern void drop_super_exclusive(struct super_block *sb);
3294 extern void iterate_supers(void (*)(struct super_block *, void *), void *);
3295 extern void iterate_supers_type(struct file_system_type *,
3296 void (*)(struct super_block *, void *), void *);
3297
3298 extern int dcache_dir_open(struct inode *, struct file *);
3299 extern int dcache_dir_close(struct inode *, struct file *);
3300 extern loff_t dcache_dir_lseek(struct file *, loff_t, int);
3301 extern int dcache_readdir(struct file *, struct dir_context *);
3302 extern int simple_setattr(struct mnt_idmap *, struct dentry *,
3303 struct iattr *);
3304 extern int simple_getattr(struct mnt_idmap *, const struct path *,
3305 struct kstat *, u32, unsigned int);
3306 extern int simple_statfs(struct dentry *, struct kstatfs *);
3307 extern int simple_open(struct inode *inode, struct file *file);
3308 extern int simple_link(struct dentry *, struct inode *, struct dentry *);
3309 extern int simple_unlink(struct inode *, struct dentry *);
3310 extern int simple_rmdir(struct inode *, struct dentry *);
3311 void simple_rename_timestamp(struct inode *old_dir, struct dentry *old_dentry,
3312 struct inode *new_dir, struct dentry *new_dentry);
3313 extern int simple_rename_exchange(struct inode *old_dir, struct dentry *old_dentry,
3314 struct inode *new_dir, struct dentry *new_dentry);
3315 extern int simple_rename(struct mnt_idmap *, struct inode *,
3316 struct dentry *, struct inode *, struct dentry *,
3317 unsigned int);
3318 extern void simple_recursive_removal(struct dentry *,
3319 void (*callback)(struct dentry *));
3320 extern int noop_fsync(struct file *, loff_t, loff_t, int);
3321 extern ssize_t noop_direct_IO(struct kiocb *iocb, struct iov_iter *iter);
3322 extern int simple_empty(struct dentry *);
3323 extern int simple_write_begin(struct file *file, struct address_space *mapping,
3324 loff_t pos, unsigned len,
3325 struct page **pagep, void **fsdata);
3326 extern const struct address_space_operations ram_aops;
3327 extern int always_delete_dentry(const struct dentry *);
3328 extern struct inode *alloc_anon_inode(struct super_block *);
3329 extern int simple_nosetlease(struct file *, int, struct file_lease **, void **);
3330 extern const struct dentry_operations simple_dentry_operations;
3331
3332 extern struct dentry *simple_lookup(struct inode *, struct dentry *, unsigned int flags);
3333 extern ssize_t generic_read_dir(struct file *, char __user *, size_t, loff_t *);
3334 extern const struct file_operations simple_dir_operations;
3335 extern const struct inode_operations simple_dir_inode_operations;
3336 extern void make_empty_dir_inode(struct inode *inode);
3337 extern bool is_empty_dir_inode(struct inode *inode);
3338 struct tree_descr { const char *name; const struct file_operations *ops; int mode; };
3339 struct dentry *d_alloc_name(struct dentry *, const char *);
3340 extern int simple_fill_super(struct super_block *, unsigned long,
3341 const struct tree_descr *);
3342 extern int simple_pin_fs(struct file_system_type *, struct vfsmount **mount, int *count);
3343 extern void simple_release_fs(struct vfsmount **mount, int *count);
3344
3345 extern ssize_t simple_read_from_buffer(void __user *to, size_t count,
3346 loff_t *ppos, const void *from, size_t available);
3347 extern ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos,
3348 const void __user *from, size_t count);
3349
3350 struct offset_ctx {
3351 struct maple_tree mt;
3352 unsigned long next_offset;
3353 };
3354
3355 void simple_offset_init(struct offset_ctx *octx);
3356 int simple_offset_add(struct offset_ctx *octx, struct dentry *dentry);
3357 void simple_offset_remove(struct offset_ctx *octx, struct dentry *dentry);
3358 int simple_offset_empty(struct dentry *dentry);
3359 int simple_offset_rename(struct inode *old_dir, struct dentry *old_dentry,
3360 struct inode *new_dir, struct dentry *new_dentry);
3361 int simple_offset_rename_exchange(struct inode *old_dir,
3362 struct dentry *old_dentry,
3363 struct inode *new_dir,
3364 struct dentry *new_dentry);
3365 void simple_offset_destroy(struct offset_ctx *octx);
3366
3367 extern const struct file_operations simple_offset_dir_operations;
3368
3369 extern int __generic_file_fsync(struct file *, loff_t, loff_t, int);
3370 extern int generic_file_fsync(struct file *, loff_t, loff_t, int);
3371
3372 extern int generic_check_addressable(unsigned, u64);
3373
3374 extern void generic_set_sb_d_ops(struct super_block *sb);
3375
sb_has_encoding(const struct super_block * sb)3376 static inline bool sb_has_encoding(const struct super_block *sb)
3377 {
3378 #if IS_ENABLED(CONFIG_UNICODE)
3379 return !!sb->s_encoding;
3380 #else
3381 return false;
3382 #endif
3383 }
3384
3385 int may_setattr(struct mnt_idmap *idmap, struct inode *inode,
3386 unsigned int ia_valid);
3387 int setattr_prepare(struct mnt_idmap *, struct dentry *, struct iattr *);
3388 extern int inode_newsize_ok(const struct inode *, loff_t offset);
3389 void setattr_copy(struct mnt_idmap *, struct inode *inode,
3390 const struct iattr *attr);
3391
3392 extern int file_update_time(struct file *file);
3393
vma_is_dax(const struct vm_area_struct * vma)3394 static inline bool vma_is_dax(const struct vm_area_struct *vma)
3395 {
3396 return vma->vm_file && IS_DAX(vma->vm_file->f_mapping->host);
3397 }
3398
vma_is_fsdax(struct vm_area_struct * vma)3399 static inline bool vma_is_fsdax(struct vm_area_struct *vma)
3400 {
3401 struct inode *inode;
3402
3403 if (!IS_ENABLED(CONFIG_FS_DAX) || !vma->vm_file)
3404 return false;
3405 if (!vma_is_dax(vma))
3406 return false;
3407 inode = file_inode(vma->vm_file);
3408 if (S_ISCHR(inode->i_mode))
3409 return false; /* device-dax */
3410 return true;
3411 }
3412
iocb_flags(struct file * file)3413 static inline int iocb_flags(struct file *file)
3414 {
3415 int res = 0;
3416 if (file->f_flags & O_APPEND)
3417 res |= IOCB_APPEND;
3418 if (file->f_flags & O_DIRECT)
3419 res |= IOCB_DIRECT;
3420 if (file->f_flags & O_DSYNC)
3421 res |= IOCB_DSYNC;
3422 if (file->f_flags & __O_SYNC)
3423 res |= IOCB_SYNC;
3424 return res;
3425 }
3426
kiocb_set_rw_flags(struct kiocb * ki,rwf_t flags)3427 static inline int kiocb_set_rw_flags(struct kiocb *ki, rwf_t flags)
3428 {
3429 int kiocb_flags = 0;
3430
3431 /* make sure there's no overlap between RWF and private IOCB flags */
3432 BUILD_BUG_ON((__force int) RWF_SUPPORTED & IOCB_EVENTFD);
3433
3434 if (!flags)
3435 return 0;
3436 if (unlikely(flags & ~RWF_SUPPORTED))
3437 return -EOPNOTSUPP;
3438 if (unlikely((flags & RWF_APPEND) && (flags & RWF_NOAPPEND)))
3439 return -EINVAL;
3440
3441 if (flags & RWF_NOWAIT) {
3442 if (!(ki->ki_filp->f_mode & FMODE_NOWAIT))
3443 return -EOPNOTSUPP;
3444 kiocb_flags |= IOCB_NOIO;
3445 }
3446 kiocb_flags |= (__force int) (flags & RWF_SUPPORTED);
3447 if (flags & RWF_SYNC)
3448 kiocb_flags |= IOCB_DSYNC;
3449
3450 if ((flags & RWF_NOAPPEND) && (ki->ki_flags & IOCB_APPEND)) {
3451 if (IS_APPEND(file_inode(ki->ki_filp)))
3452 return -EPERM;
3453 ki->ki_flags &= ~IOCB_APPEND;
3454 }
3455
3456 ki->ki_flags |= kiocb_flags;
3457 return 0;
3458 }
3459
parent_ino(struct dentry * dentry)3460 static inline ino_t parent_ino(struct dentry *dentry)
3461 {
3462 ino_t res;
3463
3464 /*
3465 * Don't strictly need d_lock here? If the parent ino could change
3466 * then surely we'd have a deeper race in the caller?
3467 */
3468 spin_lock(&dentry->d_lock);
3469 res = dentry->d_parent->d_inode->i_ino;
3470 spin_unlock(&dentry->d_lock);
3471 return res;
3472 }
3473
3474 /* Transaction based IO helpers */
3475
3476 /*
3477 * An argresp is stored in an allocated page and holds the
3478 * size of the argument or response, along with its content
3479 */
3480 struct simple_transaction_argresp {
3481 ssize_t size;
3482 char data[];
3483 };
3484
3485 #define SIMPLE_TRANSACTION_LIMIT (PAGE_SIZE - sizeof(struct simple_transaction_argresp))
3486
3487 char *simple_transaction_get(struct file *file, const char __user *buf,
3488 size_t size);
3489 ssize_t simple_transaction_read(struct file *file, char __user *buf,
3490 size_t size, loff_t *pos);
3491 int simple_transaction_release(struct inode *inode, struct file *file);
3492
3493 void simple_transaction_set(struct file *file, size_t n);
3494
3495 /*
3496 * simple attribute files
3497 *
3498 * These attributes behave similar to those in sysfs:
3499 *
3500 * Writing to an attribute immediately sets a value, an open file can be
3501 * written to multiple times.
3502 *
3503 * Reading from an attribute creates a buffer from the value that might get
3504 * read with multiple read calls. When the attribute has been read
3505 * completely, no further read calls are possible until the file is opened
3506 * again.
3507 *
3508 * All attributes contain a text representation of a numeric value
3509 * that are accessed with the get() and set() functions.
3510 */
3511 #define DEFINE_SIMPLE_ATTRIBUTE_XSIGNED(__fops, __get, __set, __fmt, __is_signed) \
3512 static int __fops ## _open(struct inode *inode, struct file *file) \
3513 { \
3514 __simple_attr_check_format(__fmt, 0ull); \
3515 return simple_attr_open(inode, file, __get, __set, __fmt); \
3516 } \
3517 static const struct file_operations __fops = { \
3518 .owner = THIS_MODULE, \
3519 .open = __fops ## _open, \
3520 .release = simple_attr_release, \
3521 .read = simple_attr_read, \
3522 .write = (__is_signed) ? simple_attr_write_signed : simple_attr_write, \
3523 .llseek = generic_file_llseek, \
3524 }
3525
3526 #define DEFINE_SIMPLE_ATTRIBUTE(__fops, __get, __set, __fmt) \
3527 DEFINE_SIMPLE_ATTRIBUTE_XSIGNED(__fops, __get, __set, __fmt, false)
3528
3529 #define DEFINE_SIMPLE_ATTRIBUTE_SIGNED(__fops, __get, __set, __fmt) \
3530 DEFINE_SIMPLE_ATTRIBUTE_XSIGNED(__fops, __get, __set, __fmt, true)
3531
3532 static inline __printf(1, 2)
__simple_attr_check_format(const char * fmt,...)3533 void __simple_attr_check_format(const char *fmt, ...)
3534 {
3535 /* don't do anything, just let the compiler check the arguments; */
3536 }
3537
3538 int simple_attr_open(struct inode *inode, struct file *file,
3539 int (*get)(void *, u64 *), int (*set)(void *, u64),
3540 const char *fmt);
3541 int simple_attr_release(struct inode *inode, struct file *file);
3542 ssize_t simple_attr_read(struct file *file, char __user *buf,
3543 size_t len, loff_t *ppos);
3544 ssize_t simple_attr_write(struct file *file, const char __user *buf,
3545 size_t len, loff_t *ppos);
3546 ssize_t simple_attr_write_signed(struct file *file, const char __user *buf,
3547 size_t len, loff_t *ppos);
3548
3549 struct ctl_table;
3550 int __init list_bdev_fs_names(char *buf, size_t size);
3551
3552 #define __FMODE_EXEC ((__force int) FMODE_EXEC)
3553 #define __FMODE_NONOTIFY ((__force int) FMODE_NONOTIFY)
3554
3555 #define ACC_MODE(x) ("\004\002\006\006"[(x)&O_ACCMODE])
3556 #define OPEN_FMODE(flag) ((__force fmode_t)(((flag + 1) & O_ACCMODE) | \
3557 (flag & __FMODE_NONOTIFY)))
3558
is_sxid(umode_t mode)3559 static inline bool is_sxid(umode_t mode)
3560 {
3561 return mode & (S_ISUID | S_ISGID);
3562 }
3563
check_sticky(struct mnt_idmap * idmap,struct inode * dir,struct inode * inode)3564 static inline int check_sticky(struct mnt_idmap *idmap,
3565 struct inode *dir, struct inode *inode)
3566 {
3567 if (!(dir->i_mode & S_ISVTX))
3568 return 0;
3569
3570 return __check_sticky(idmap, dir, inode);
3571 }
3572
inode_has_no_xattr(struct inode * inode)3573 static inline void inode_has_no_xattr(struct inode *inode)
3574 {
3575 if (!is_sxid(inode->i_mode) && (inode->i_sb->s_flags & SB_NOSEC))
3576 inode->i_flags |= S_NOSEC;
3577 }
3578
is_root_inode(struct inode * inode)3579 static inline bool is_root_inode(struct inode *inode)
3580 {
3581 return inode == inode->i_sb->s_root->d_inode;
3582 }
3583
dir_emit(struct dir_context * ctx,const char * name,int namelen,u64 ino,unsigned type)3584 static inline bool dir_emit(struct dir_context *ctx,
3585 const char *name, int namelen,
3586 u64 ino, unsigned type)
3587 {
3588 return ctx->actor(ctx, name, namelen, ctx->pos, ino, type);
3589 }
dir_emit_dot(struct file * file,struct dir_context * ctx)3590 static inline bool dir_emit_dot(struct file *file, struct dir_context *ctx)
3591 {
3592 return ctx->actor(ctx, ".", 1, ctx->pos,
3593 file->f_path.dentry->d_inode->i_ino, DT_DIR);
3594 }
dir_emit_dotdot(struct file * file,struct dir_context * ctx)3595 static inline bool dir_emit_dotdot(struct file *file, struct dir_context *ctx)
3596 {
3597 return ctx->actor(ctx, "..", 2, ctx->pos,
3598 parent_ino(file->f_path.dentry), DT_DIR);
3599 }
dir_emit_dots(struct file * file,struct dir_context * ctx)3600 static inline bool dir_emit_dots(struct file *file, struct dir_context *ctx)
3601 {
3602 if (ctx->pos == 0) {
3603 if (!dir_emit_dot(file, ctx))
3604 return false;
3605 ctx->pos = 1;
3606 }
3607 if (ctx->pos == 1) {
3608 if (!dir_emit_dotdot(file, ctx))
3609 return false;
3610 ctx->pos = 2;
3611 }
3612 return true;
3613 }
dir_relax(struct inode * inode)3614 static inline bool dir_relax(struct inode *inode)
3615 {
3616 inode_unlock(inode);
3617 inode_lock(inode);
3618 return !IS_DEADDIR(inode);
3619 }
3620
dir_relax_shared(struct inode * inode)3621 static inline bool dir_relax_shared(struct inode *inode)
3622 {
3623 inode_unlock_shared(inode);
3624 inode_lock_shared(inode);
3625 return !IS_DEADDIR(inode);
3626 }
3627
3628 extern bool path_noexec(const struct path *path);
3629 extern void inode_nohighmem(struct inode *inode);
3630
3631 /* mm/fadvise.c */
3632 extern int vfs_fadvise(struct file *file, loff_t offset, loff_t len,
3633 int advice);
3634 extern int generic_fadvise(struct file *file, loff_t offset, loff_t len,
3635 int advice);
3636
3637 #endif /* _LINUX_FS_H */
3638