xref: /linux/fs/stat.c (revision a031fe8d1d32898582e36ccbffa9847d16f67aa2)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  linux/fs/stat.c
4  *
5  *  Copyright (C) 1991, 1992  Linus Torvalds
6  */
7 
8 #include <linux/blkdev.h>
9 #include <linux/export.h>
10 #include <linux/mm.h>
11 #include <linux/errno.h>
12 #include <linux/file.h>
13 #include <linux/highuid.h>
14 #include <linux/fs.h>
15 #include <linux/namei.h>
16 #include <linux/security.h>
17 #include <linux/cred.h>
18 #include <linux/syscalls.h>
19 #include <linux/pagemap.h>
20 #include <linux/compat.h>
21 #include <linux/iversion.h>
22 
23 #include <linux/uaccess.h>
24 #include <asm/unistd.h>
25 
26 #include "internal.h"
27 #include "mount.h"
28 
29 /**
30  * fill_mg_cmtime - Fill in the mtime and ctime and flag ctime as QUERIED
31  * @stat: where to store the resulting values
32  * @request_mask: STATX_* values requested
33  * @inode: inode from which to grab the c/mtime
34  *
35  * Given @inode, grab the ctime and mtime out if it and store the result
36  * in @stat. When fetching the value, flag it as queried so the next write
37  * will use a fine-grained timestamp.
38  */
39 void fill_mg_cmtime(struct kstat *stat, u32 request_mask, struct inode *inode)
40 {
41 	atomic_long_t *pnsec = (atomic_long_t *)&inode->__i_ctime.tv_nsec;
42 
43 	/* If neither time was requested, then don't report them */
44 	if (!(request_mask & (STATX_CTIME|STATX_MTIME))) {
45 		stat->result_mask &= ~(STATX_CTIME|STATX_MTIME);
46 		return;
47 	}
48 
49 	stat->mtime = inode->i_mtime;
50 	stat->ctime.tv_sec = inode->__i_ctime.tv_sec;
51 	/*
52 	 * Atomically set the QUERIED flag and fetch the new value with
53 	 * the flag masked off.
54 	 */
55 	stat->ctime.tv_nsec = atomic_long_fetch_or(I_CTIME_QUERIED, pnsec) &
56 					~I_CTIME_QUERIED;
57 }
58 EXPORT_SYMBOL(fill_mg_cmtime);
59 
60 /**
61  * generic_fillattr - Fill in the basic attributes from the inode struct
62  * @idmap:		idmap of the mount the inode was found from
63  * @request_mask:	statx request_mask
64  * @inode:		Inode to use as the source
65  * @stat:		Where to fill in the attributes
66  *
67  * Fill in the basic attributes in the kstat structure from data that's to be
68  * found on the VFS inode structure.  This is the default if no getattr inode
69  * operation is supplied.
70  *
71  * If the inode has been found through an idmapped mount the idmap of
72  * the vfsmount must be passed through @idmap. This function will then
73  * take care to map the inode according to @idmap before filling in the
74  * uid and gid filds. On non-idmapped mounts or if permission checking is to be
75  * performed on the raw inode simply passs @nop_mnt_idmap.
76  */
77 void generic_fillattr(struct mnt_idmap *idmap, u32 request_mask,
78 		      struct inode *inode, struct kstat *stat)
79 {
80 	vfsuid_t vfsuid = i_uid_into_vfsuid(idmap, inode);
81 	vfsgid_t vfsgid = i_gid_into_vfsgid(idmap, inode);
82 
83 	stat->dev = inode->i_sb->s_dev;
84 	stat->ino = inode->i_ino;
85 	stat->mode = inode->i_mode;
86 	stat->nlink = inode->i_nlink;
87 	stat->uid = vfsuid_into_kuid(vfsuid);
88 	stat->gid = vfsgid_into_kgid(vfsgid);
89 	stat->rdev = inode->i_rdev;
90 	stat->size = i_size_read(inode);
91 	stat->atime = inode->i_atime;
92 
93 	if (is_mgtime(inode)) {
94 		fill_mg_cmtime(stat, request_mask, inode);
95 	} else {
96 		stat->mtime = inode->i_mtime;
97 		stat->ctime = inode_get_ctime(inode);
98 	}
99 
100 	stat->blksize = i_blocksize(inode);
101 	stat->blocks = inode->i_blocks;
102 
103 	if ((request_mask & STATX_CHANGE_COOKIE) && IS_I_VERSION(inode)) {
104 		stat->result_mask |= STATX_CHANGE_COOKIE;
105 		stat->change_cookie = inode_query_iversion(inode);
106 	}
107 
108 }
109 EXPORT_SYMBOL(generic_fillattr);
110 
111 /**
112  * generic_fill_statx_attr - Fill in the statx attributes from the inode flags
113  * @inode:	Inode to use as the source
114  * @stat:	Where to fill in the attribute flags
115  *
116  * Fill in the STATX_ATTR_* flags in the kstat structure for properties of the
117  * inode that are published on i_flags and enforced by the VFS.
118  */
119 void generic_fill_statx_attr(struct inode *inode, struct kstat *stat)
120 {
121 	if (inode->i_flags & S_IMMUTABLE)
122 		stat->attributes |= STATX_ATTR_IMMUTABLE;
123 	if (inode->i_flags & S_APPEND)
124 		stat->attributes |= STATX_ATTR_APPEND;
125 	stat->attributes_mask |= KSTAT_ATTR_VFS_FLAGS;
126 }
127 EXPORT_SYMBOL(generic_fill_statx_attr);
128 
129 /**
130  * vfs_getattr_nosec - getattr without security checks
131  * @path: file to get attributes from
132  * @stat: structure to return attributes in
133  * @request_mask: STATX_xxx flags indicating what the caller wants
134  * @query_flags: Query mode (AT_STATX_SYNC_TYPE)
135  *
136  * Get attributes without calling security_inode_getattr.
137  *
138  * Currently the only caller other than vfs_getattr is internal to the
139  * filehandle lookup code, which uses only the inode number and returns no
140  * attributes to any user.  Any other code probably wants vfs_getattr.
141  */
142 int vfs_getattr_nosec(const struct path *path, struct kstat *stat,
143 		      u32 request_mask, unsigned int query_flags)
144 {
145 	struct mnt_idmap *idmap;
146 	struct inode *inode = d_backing_inode(path->dentry);
147 
148 	memset(stat, 0, sizeof(*stat));
149 	stat->result_mask |= STATX_BASIC_STATS;
150 	query_flags &= AT_STATX_SYNC_TYPE;
151 
152 	/* allow the fs to override these if it really wants to */
153 	/* SB_NOATIME means filesystem supplies dummy atime value */
154 	if (inode->i_sb->s_flags & SB_NOATIME)
155 		stat->result_mask &= ~STATX_ATIME;
156 
157 	/*
158 	 * Note: If you add another clause to set an attribute flag, please
159 	 * update attributes_mask below.
160 	 */
161 	if (IS_AUTOMOUNT(inode))
162 		stat->attributes |= STATX_ATTR_AUTOMOUNT;
163 
164 	if (IS_DAX(inode))
165 		stat->attributes |= STATX_ATTR_DAX;
166 
167 	stat->attributes_mask |= (STATX_ATTR_AUTOMOUNT |
168 				  STATX_ATTR_DAX);
169 
170 	idmap = mnt_idmap(path->mnt);
171 	if (inode->i_op->getattr)
172 		return inode->i_op->getattr(idmap, path, stat,
173 					    request_mask, query_flags);
174 
175 	generic_fillattr(idmap, request_mask, inode, stat);
176 	return 0;
177 }
178 EXPORT_SYMBOL(vfs_getattr_nosec);
179 
180 /*
181  * vfs_getattr - Get the enhanced basic attributes of a file
182  * @path: The file of interest
183  * @stat: Where to return the statistics
184  * @request_mask: STATX_xxx flags indicating what the caller wants
185  * @query_flags: Query mode (AT_STATX_SYNC_TYPE)
186  *
187  * Ask the filesystem for a file's attributes.  The caller must indicate in
188  * request_mask and query_flags to indicate what they want.
189  *
190  * If the file is remote, the filesystem can be forced to update the attributes
191  * from the backing store by passing AT_STATX_FORCE_SYNC in query_flags or can
192  * suppress the update by passing AT_STATX_DONT_SYNC.
193  *
194  * Bits must have been set in request_mask to indicate which attributes the
195  * caller wants retrieving.  Any such attribute not requested may be returned
196  * anyway, but the value may be approximate, and, if remote, may not have been
197  * synchronised with the server.
198  *
199  * 0 will be returned on success, and a -ve error code if unsuccessful.
200  */
201 int vfs_getattr(const struct path *path, struct kstat *stat,
202 		u32 request_mask, unsigned int query_flags)
203 {
204 	int retval;
205 
206 	retval = security_inode_getattr(path);
207 	if (retval)
208 		return retval;
209 	return vfs_getattr_nosec(path, stat, request_mask, query_flags);
210 }
211 EXPORT_SYMBOL(vfs_getattr);
212 
213 /**
214  * vfs_fstat - Get the basic attributes by file descriptor
215  * @fd: The file descriptor referring to the file of interest
216  * @stat: The result structure to fill in.
217  *
218  * This function is a wrapper around vfs_getattr().  The main difference is
219  * that it uses a file descriptor to determine the file location.
220  *
221  * 0 will be returned on success, and a -ve error code if unsuccessful.
222  */
223 int vfs_fstat(int fd, struct kstat *stat)
224 {
225 	struct fd f;
226 	int error;
227 
228 	f = fdget_raw(fd);
229 	if (!f.file)
230 		return -EBADF;
231 	error = vfs_getattr(&f.file->f_path, stat, STATX_BASIC_STATS, 0);
232 	fdput(f);
233 	return error;
234 }
235 
236 int getname_statx_lookup_flags(int flags)
237 {
238 	int lookup_flags = 0;
239 
240 	if (!(flags & AT_SYMLINK_NOFOLLOW))
241 		lookup_flags |= LOOKUP_FOLLOW;
242 	if (!(flags & AT_NO_AUTOMOUNT))
243 		lookup_flags |= LOOKUP_AUTOMOUNT;
244 	if (flags & AT_EMPTY_PATH)
245 		lookup_flags |= LOOKUP_EMPTY;
246 
247 	return lookup_flags;
248 }
249 
250 /**
251  * vfs_statx - Get basic and extra attributes by filename
252  * @dfd: A file descriptor representing the base dir for a relative filename
253  * @filename: The name of the file of interest
254  * @flags: Flags to control the query
255  * @stat: The result structure to fill in.
256  * @request_mask: STATX_xxx flags indicating what the caller wants
257  *
258  * This function is a wrapper around vfs_getattr().  The main difference is
259  * that it uses a filename and base directory to determine the file location.
260  * Additionally, the use of AT_SYMLINK_NOFOLLOW in flags will prevent a symlink
261  * at the given name from being referenced.
262  *
263  * 0 will be returned on success, and a -ve error code if unsuccessful.
264  */
265 static int vfs_statx(int dfd, struct filename *filename, int flags,
266 	      struct kstat *stat, u32 request_mask)
267 {
268 	struct path path;
269 	unsigned int lookup_flags = getname_statx_lookup_flags(flags);
270 	int error;
271 
272 	if (flags & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT | AT_EMPTY_PATH |
273 		      AT_STATX_SYNC_TYPE))
274 		return -EINVAL;
275 
276 retry:
277 	error = filename_lookup(dfd, filename, lookup_flags, &path, NULL);
278 	if (error)
279 		goto out;
280 
281 	error = vfs_getattr(&path, stat, request_mask, flags);
282 
283 	stat->mnt_id = real_mount(path.mnt)->mnt_id;
284 	stat->result_mask |= STATX_MNT_ID;
285 
286 	if (path.mnt->mnt_root == path.dentry)
287 		stat->attributes |= STATX_ATTR_MOUNT_ROOT;
288 	stat->attributes_mask |= STATX_ATTR_MOUNT_ROOT;
289 
290 	/* Handle STATX_DIOALIGN for block devices. */
291 	if (request_mask & STATX_DIOALIGN) {
292 		struct inode *inode = d_backing_inode(path.dentry);
293 
294 		if (S_ISBLK(inode->i_mode))
295 			bdev_statx_dioalign(inode, stat);
296 	}
297 
298 	path_put(&path);
299 	if (retry_estale(error, lookup_flags)) {
300 		lookup_flags |= LOOKUP_REVAL;
301 		goto retry;
302 	}
303 out:
304 	return error;
305 }
306 
307 int vfs_fstatat(int dfd, const char __user *filename,
308 			      struct kstat *stat, int flags)
309 {
310 	int ret;
311 	int statx_flags = flags | AT_NO_AUTOMOUNT;
312 	struct filename *name;
313 
314 	name = getname_flags(filename, getname_statx_lookup_flags(statx_flags), NULL);
315 	ret = vfs_statx(dfd, name, statx_flags, stat, STATX_BASIC_STATS);
316 	putname(name);
317 
318 	return ret;
319 }
320 
321 #ifdef __ARCH_WANT_OLD_STAT
322 
323 /*
324  * For backward compatibility?  Maybe this should be moved
325  * into arch/i386 instead?
326  */
327 static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * statbuf)
328 {
329 	static int warncount = 5;
330 	struct __old_kernel_stat tmp;
331 
332 	if (warncount > 0) {
333 		warncount--;
334 		printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.\n",
335 			current->comm);
336 	} else if (warncount < 0) {
337 		/* it's laughable, but... */
338 		warncount = 0;
339 	}
340 
341 	memset(&tmp, 0, sizeof(struct __old_kernel_stat));
342 	tmp.st_dev = old_encode_dev(stat->dev);
343 	tmp.st_ino = stat->ino;
344 	if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
345 		return -EOVERFLOW;
346 	tmp.st_mode = stat->mode;
347 	tmp.st_nlink = stat->nlink;
348 	if (tmp.st_nlink != stat->nlink)
349 		return -EOVERFLOW;
350 	SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
351 	SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
352 	tmp.st_rdev = old_encode_dev(stat->rdev);
353 #if BITS_PER_LONG == 32
354 	if (stat->size > MAX_NON_LFS)
355 		return -EOVERFLOW;
356 #endif
357 	tmp.st_size = stat->size;
358 	tmp.st_atime = stat->atime.tv_sec;
359 	tmp.st_mtime = stat->mtime.tv_sec;
360 	tmp.st_ctime = stat->ctime.tv_sec;
361 	return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
362 }
363 
364 SYSCALL_DEFINE2(stat, const char __user *, filename,
365 		struct __old_kernel_stat __user *, statbuf)
366 {
367 	struct kstat stat;
368 	int error;
369 
370 	error = vfs_stat(filename, &stat);
371 	if (error)
372 		return error;
373 
374 	return cp_old_stat(&stat, statbuf);
375 }
376 
377 SYSCALL_DEFINE2(lstat, const char __user *, filename,
378 		struct __old_kernel_stat __user *, statbuf)
379 {
380 	struct kstat stat;
381 	int error;
382 
383 	error = vfs_lstat(filename, &stat);
384 	if (error)
385 		return error;
386 
387 	return cp_old_stat(&stat, statbuf);
388 }
389 
390 SYSCALL_DEFINE2(fstat, unsigned int, fd, struct __old_kernel_stat __user *, statbuf)
391 {
392 	struct kstat stat;
393 	int error = vfs_fstat(fd, &stat);
394 
395 	if (!error)
396 		error = cp_old_stat(&stat, statbuf);
397 
398 	return error;
399 }
400 
401 #endif /* __ARCH_WANT_OLD_STAT */
402 
403 #ifdef __ARCH_WANT_NEW_STAT
404 
405 #if BITS_PER_LONG == 32
406 #  define choose_32_64(a,b) a
407 #else
408 #  define choose_32_64(a,b) b
409 #endif
410 
411 #ifndef INIT_STRUCT_STAT_PADDING
412 #  define INIT_STRUCT_STAT_PADDING(st) memset(&st, 0, sizeof(st))
413 #endif
414 
415 static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf)
416 {
417 	struct stat tmp;
418 
419 	if (sizeof(tmp.st_dev) < 4 && !old_valid_dev(stat->dev))
420 		return -EOVERFLOW;
421 	if (sizeof(tmp.st_rdev) < 4 && !old_valid_dev(stat->rdev))
422 		return -EOVERFLOW;
423 #if BITS_PER_LONG == 32
424 	if (stat->size > MAX_NON_LFS)
425 		return -EOVERFLOW;
426 #endif
427 
428 	INIT_STRUCT_STAT_PADDING(tmp);
429 	tmp.st_dev = new_encode_dev(stat->dev);
430 	tmp.st_ino = stat->ino;
431 	if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
432 		return -EOVERFLOW;
433 	tmp.st_mode = stat->mode;
434 	tmp.st_nlink = stat->nlink;
435 	if (tmp.st_nlink != stat->nlink)
436 		return -EOVERFLOW;
437 	SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
438 	SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
439 	tmp.st_rdev = new_encode_dev(stat->rdev);
440 	tmp.st_size = stat->size;
441 	tmp.st_atime = stat->atime.tv_sec;
442 	tmp.st_mtime = stat->mtime.tv_sec;
443 	tmp.st_ctime = stat->ctime.tv_sec;
444 #ifdef STAT_HAVE_NSEC
445 	tmp.st_atime_nsec = stat->atime.tv_nsec;
446 	tmp.st_mtime_nsec = stat->mtime.tv_nsec;
447 	tmp.st_ctime_nsec = stat->ctime.tv_nsec;
448 #endif
449 	tmp.st_blocks = stat->blocks;
450 	tmp.st_blksize = stat->blksize;
451 	return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
452 }
453 
454 SYSCALL_DEFINE2(newstat, const char __user *, filename,
455 		struct stat __user *, statbuf)
456 {
457 	struct kstat stat;
458 	int error = vfs_stat(filename, &stat);
459 
460 	if (error)
461 		return error;
462 	return cp_new_stat(&stat, statbuf);
463 }
464 
465 SYSCALL_DEFINE2(newlstat, const char __user *, filename,
466 		struct stat __user *, statbuf)
467 {
468 	struct kstat stat;
469 	int error;
470 
471 	error = vfs_lstat(filename, &stat);
472 	if (error)
473 		return error;
474 
475 	return cp_new_stat(&stat, statbuf);
476 }
477 
478 #if !defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_SYS_NEWFSTATAT)
479 SYSCALL_DEFINE4(newfstatat, int, dfd, const char __user *, filename,
480 		struct stat __user *, statbuf, int, flag)
481 {
482 	struct kstat stat;
483 	int error;
484 
485 	error = vfs_fstatat(dfd, filename, &stat, flag);
486 	if (error)
487 		return error;
488 	return cp_new_stat(&stat, statbuf);
489 }
490 #endif
491 
492 SYSCALL_DEFINE2(newfstat, unsigned int, fd, struct stat __user *, statbuf)
493 {
494 	struct kstat stat;
495 	int error = vfs_fstat(fd, &stat);
496 
497 	if (!error)
498 		error = cp_new_stat(&stat, statbuf);
499 
500 	return error;
501 }
502 #endif
503 
504 static int do_readlinkat(int dfd, const char __user *pathname,
505 			 char __user *buf, int bufsiz)
506 {
507 	struct path path;
508 	int error;
509 	int empty = 0;
510 	unsigned int lookup_flags = LOOKUP_EMPTY;
511 
512 	if (bufsiz <= 0)
513 		return -EINVAL;
514 
515 retry:
516 	error = user_path_at_empty(dfd, pathname, lookup_flags, &path, &empty);
517 	if (!error) {
518 		struct inode *inode = d_backing_inode(path.dentry);
519 
520 		error = empty ? -ENOENT : -EINVAL;
521 		/*
522 		 * AFS mountpoints allow readlink(2) but are not symlinks
523 		 */
524 		if (d_is_symlink(path.dentry) || inode->i_op->readlink) {
525 			error = security_inode_readlink(path.dentry);
526 			if (!error) {
527 				touch_atime(&path);
528 				error = vfs_readlink(path.dentry, buf, bufsiz);
529 			}
530 		}
531 		path_put(&path);
532 		if (retry_estale(error, lookup_flags)) {
533 			lookup_flags |= LOOKUP_REVAL;
534 			goto retry;
535 		}
536 	}
537 	return error;
538 }
539 
540 SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname,
541 		char __user *, buf, int, bufsiz)
542 {
543 	return do_readlinkat(dfd, pathname, buf, bufsiz);
544 }
545 
546 SYSCALL_DEFINE3(readlink, const char __user *, path, char __user *, buf,
547 		int, bufsiz)
548 {
549 	return do_readlinkat(AT_FDCWD, path, buf, bufsiz);
550 }
551 
552 
553 /* ---------- LFS-64 ----------- */
554 #if defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_COMPAT_STAT64)
555 
556 #ifndef INIT_STRUCT_STAT64_PADDING
557 #  define INIT_STRUCT_STAT64_PADDING(st) memset(&st, 0, sizeof(st))
558 #endif
559 
560 static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf)
561 {
562 	struct stat64 tmp;
563 
564 	INIT_STRUCT_STAT64_PADDING(tmp);
565 #ifdef CONFIG_MIPS
566 	/* mips has weird padding, so we don't get 64 bits there */
567 	tmp.st_dev = new_encode_dev(stat->dev);
568 	tmp.st_rdev = new_encode_dev(stat->rdev);
569 #else
570 	tmp.st_dev = huge_encode_dev(stat->dev);
571 	tmp.st_rdev = huge_encode_dev(stat->rdev);
572 #endif
573 	tmp.st_ino = stat->ino;
574 	if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
575 		return -EOVERFLOW;
576 #ifdef STAT64_HAS_BROKEN_ST_INO
577 	tmp.__st_ino = stat->ino;
578 #endif
579 	tmp.st_mode = stat->mode;
580 	tmp.st_nlink = stat->nlink;
581 	tmp.st_uid = from_kuid_munged(current_user_ns(), stat->uid);
582 	tmp.st_gid = from_kgid_munged(current_user_ns(), stat->gid);
583 	tmp.st_atime = stat->atime.tv_sec;
584 	tmp.st_atime_nsec = stat->atime.tv_nsec;
585 	tmp.st_mtime = stat->mtime.tv_sec;
586 	tmp.st_mtime_nsec = stat->mtime.tv_nsec;
587 	tmp.st_ctime = stat->ctime.tv_sec;
588 	tmp.st_ctime_nsec = stat->ctime.tv_nsec;
589 	tmp.st_size = stat->size;
590 	tmp.st_blocks = stat->blocks;
591 	tmp.st_blksize = stat->blksize;
592 	return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
593 }
594 
595 SYSCALL_DEFINE2(stat64, const char __user *, filename,
596 		struct stat64 __user *, statbuf)
597 {
598 	struct kstat stat;
599 	int error = vfs_stat(filename, &stat);
600 
601 	if (!error)
602 		error = cp_new_stat64(&stat, statbuf);
603 
604 	return error;
605 }
606 
607 SYSCALL_DEFINE2(lstat64, const char __user *, filename,
608 		struct stat64 __user *, statbuf)
609 {
610 	struct kstat stat;
611 	int error = vfs_lstat(filename, &stat);
612 
613 	if (!error)
614 		error = cp_new_stat64(&stat, statbuf);
615 
616 	return error;
617 }
618 
619 SYSCALL_DEFINE2(fstat64, unsigned long, fd, struct stat64 __user *, statbuf)
620 {
621 	struct kstat stat;
622 	int error = vfs_fstat(fd, &stat);
623 
624 	if (!error)
625 		error = cp_new_stat64(&stat, statbuf);
626 
627 	return error;
628 }
629 
630 SYSCALL_DEFINE4(fstatat64, int, dfd, const char __user *, filename,
631 		struct stat64 __user *, statbuf, int, flag)
632 {
633 	struct kstat stat;
634 	int error;
635 
636 	error = vfs_fstatat(dfd, filename, &stat, flag);
637 	if (error)
638 		return error;
639 	return cp_new_stat64(&stat, statbuf);
640 }
641 #endif /* __ARCH_WANT_STAT64 || __ARCH_WANT_COMPAT_STAT64 */
642 
643 static noinline_for_stack int
644 cp_statx(const struct kstat *stat, struct statx __user *buffer)
645 {
646 	struct statx tmp;
647 
648 	memset(&tmp, 0, sizeof(tmp));
649 
650 	/* STATX_CHANGE_COOKIE is kernel-only for now */
651 	tmp.stx_mask = stat->result_mask & ~STATX_CHANGE_COOKIE;
652 	tmp.stx_blksize = stat->blksize;
653 	/* STATX_ATTR_CHANGE_MONOTONIC is kernel-only for now */
654 	tmp.stx_attributes = stat->attributes & ~STATX_ATTR_CHANGE_MONOTONIC;
655 	tmp.stx_nlink = stat->nlink;
656 	tmp.stx_uid = from_kuid_munged(current_user_ns(), stat->uid);
657 	tmp.stx_gid = from_kgid_munged(current_user_ns(), stat->gid);
658 	tmp.stx_mode = stat->mode;
659 	tmp.stx_ino = stat->ino;
660 	tmp.stx_size = stat->size;
661 	tmp.stx_blocks = stat->blocks;
662 	tmp.stx_attributes_mask = stat->attributes_mask;
663 	tmp.stx_atime.tv_sec = stat->atime.tv_sec;
664 	tmp.stx_atime.tv_nsec = stat->atime.tv_nsec;
665 	tmp.stx_btime.tv_sec = stat->btime.tv_sec;
666 	tmp.stx_btime.tv_nsec = stat->btime.tv_nsec;
667 	tmp.stx_ctime.tv_sec = stat->ctime.tv_sec;
668 	tmp.stx_ctime.tv_nsec = stat->ctime.tv_nsec;
669 	tmp.stx_mtime.tv_sec = stat->mtime.tv_sec;
670 	tmp.stx_mtime.tv_nsec = stat->mtime.tv_nsec;
671 	tmp.stx_rdev_major = MAJOR(stat->rdev);
672 	tmp.stx_rdev_minor = MINOR(stat->rdev);
673 	tmp.stx_dev_major = MAJOR(stat->dev);
674 	tmp.stx_dev_minor = MINOR(stat->dev);
675 	tmp.stx_mnt_id = stat->mnt_id;
676 	tmp.stx_dio_mem_align = stat->dio_mem_align;
677 	tmp.stx_dio_offset_align = stat->dio_offset_align;
678 
679 	return copy_to_user(buffer, &tmp, sizeof(tmp)) ? -EFAULT : 0;
680 }
681 
682 int do_statx(int dfd, struct filename *filename, unsigned int flags,
683 	     unsigned int mask, struct statx __user *buffer)
684 {
685 	struct kstat stat;
686 	int error;
687 
688 	if (mask & STATX__RESERVED)
689 		return -EINVAL;
690 	if ((flags & AT_STATX_SYNC_TYPE) == AT_STATX_SYNC_TYPE)
691 		return -EINVAL;
692 
693 	/* STATX_CHANGE_COOKIE is kernel-only for now. Ignore requests
694 	 * from userland.
695 	 */
696 	mask &= ~STATX_CHANGE_COOKIE;
697 
698 	error = vfs_statx(dfd, filename, flags, &stat, mask);
699 	if (error)
700 		return error;
701 
702 	return cp_statx(&stat, buffer);
703 }
704 
705 /**
706  * sys_statx - System call to get enhanced stats
707  * @dfd: Base directory to pathwalk from *or* fd to stat.
708  * @filename: File to stat or "" with AT_EMPTY_PATH
709  * @flags: AT_* flags to control pathwalk.
710  * @mask: Parts of statx struct actually required.
711  * @buffer: Result buffer.
712  *
713  * Note that fstat() can be emulated by setting dfd to the fd of interest,
714  * supplying "" as the filename and setting AT_EMPTY_PATH in the flags.
715  */
716 SYSCALL_DEFINE5(statx,
717 		int, dfd, const char __user *, filename, unsigned, flags,
718 		unsigned int, mask,
719 		struct statx __user *, buffer)
720 {
721 	int ret;
722 	struct filename *name;
723 
724 	name = getname_flags(filename, getname_statx_lookup_flags(flags), NULL);
725 	ret = do_statx(dfd, name, flags, mask, buffer);
726 	putname(name);
727 
728 	return ret;
729 }
730 
731 #if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_STAT)
732 static int cp_compat_stat(struct kstat *stat, struct compat_stat __user *ubuf)
733 {
734 	struct compat_stat tmp;
735 
736 	if (sizeof(tmp.st_dev) < 4 && !old_valid_dev(stat->dev))
737 		return -EOVERFLOW;
738 	if (sizeof(tmp.st_rdev) < 4 && !old_valid_dev(stat->rdev))
739 		return -EOVERFLOW;
740 
741 	memset(&tmp, 0, sizeof(tmp));
742 	tmp.st_dev = new_encode_dev(stat->dev);
743 	tmp.st_ino = stat->ino;
744 	if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
745 		return -EOVERFLOW;
746 	tmp.st_mode = stat->mode;
747 	tmp.st_nlink = stat->nlink;
748 	if (tmp.st_nlink != stat->nlink)
749 		return -EOVERFLOW;
750 	SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
751 	SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
752 	tmp.st_rdev = new_encode_dev(stat->rdev);
753 	if ((u64) stat->size > MAX_NON_LFS)
754 		return -EOVERFLOW;
755 	tmp.st_size = stat->size;
756 	tmp.st_atime = stat->atime.tv_sec;
757 	tmp.st_atime_nsec = stat->atime.tv_nsec;
758 	tmp.st_mtime = stat->mtime.tv_sec;
759 	tmp.st_mtime_nsec = stat->mtime.tv_nsec;
760 	tmp.st_ctime = stat->ctime.tv_sec;
761 	tmp.st_ctime_nsec = stat->ctime.tv_nsec;
762 	tmp.st_blocks = stat->blocks;
763 	tmp.st_blksize = stat->blksize;
764 	return copy_to_user(ubuf, &tmp, sizeof(tmp)) ? -EFAULT : 0;
765 }
766 
767 COMPAT_SYSCALL_DEFINE2(newstat, const char __user *, filename,
768 		       struct compat_stat __user *, statbuf)
769 {
770 	struct kstat stat;
771 	int error;
772 
773 	error = vfs_stat(filename, &stat);
774 	if (error)
775 		return error;
776 	return cp_compat_stat(&stat, statbuf);
777 }
778 
779 COMPAT_SYSCALL_DEFINE2(newlstat, const char __user *, filename,
780 		       struct compat_stat __user *, statbuf)
781 {
782 	struct kstat stat;
783 	int error;
784 
785 	error = vfs_lstat(filename, &stat);
786 	if (error)
787 		return error;
788 	return cp_compat_stat(&stat, statbuf);
789 }
790 
791 #ifndef __ARCH_WANT_STAT64
792 COMPAT_SYSCALL_DEFINE4(newfstatat, unsigned int, dfd,
793 		       const char __user *, filename,
794 		       struct compat_stat __user *, statbuf, int, flag)
795 {
796 	struct kstat stat;
797 	int error;
798 
799 	error = vfs_fstatat(dfd, filename, &stat, flag);
800 	if (error)
801 		return error;
802 	return cp_compat_stat(&stat, statbuf);
803 }
804 #endif
805 
806 COMPAT_SYSCALL_DEFINE2(newfstat, unsigned int, fd,
807 		       struct compat_stat __user *, statbuf)
808 {
809 	struct kstat stat;
810 	int error = vfs_fstat(fd, &stat);
811 
812 	if (!error)
813 		error = cp_compat_stat(&stat, statbuf);
814 	return error;
815 }
816 #endif
817 
818 /* Caller is here responsible for sufficient locking (ie. inode->i_lock) */
819 void __inode_add_bytes(struct inode *inode, loff_t bytes)
820 {
821 	inode->i_blocks += bytes >> 9;
822 	bytes &= 511;
823 	inode->i_bytes += bytes;
824 	if (inode->i_bytes >= 512) {
825 		inode->i_blocks++;
826 		inode->i_bytes -= 512;
827 	}
828 }
829 EXPORT_SYMBOL(__inode_add_bytes);
830 
831 void inode_add_bytes(struct inode *inode, loff_t bytes)
832 {
833 	spin_lock(&inode->i_lock);
834 	__inode_add_bytes(inode, bytes);
835 	spin_unlock(&inode->i_lock);
836 }
837 
838 EXPORT_SYMBOL(inode_add_bytes);
839 
840 void __inode_sub_bytes(struct inode *inode, loff_t bytes)
841 {
842 	inode->i_blocks -= bytes >> 9;
843 	bytes &= 511;
844 	if (inode->i_bytes < bytes) {
845 		inode->i_blocks--;
846 		inode->i_bytes += 512;
847 	}
848 	inode->i_bytes -= bytes;
849 }
850 
851 EXPORT_SYMBOL(__inode_sub_bytes);
852 
853 void inode_sub_bytes(struct inode *inode, loff_t bytes)
854 {
855 	spin_lock(&inode->i_lock);
856 	__inode_sub_bytes(inode, bytes);
857 	spin_unlock(&inode->i_lock);
858 }
859 
860 EXPORT_SYMBOL(inode_sub_bytes);
861 
862 loff_t inode_get_bytes(struct inode *inode)
863 {
864 	loff_t ret;
865 
866 	spin_lock(&inode->i_lock);
867 	ret = __inode_get_bytes(inode);
868 	spin_unlock(&inode->i_lock);
869 	return ret;
870 }
871 
872 EXPORT_SYMBOL(inode_get_bytes);
873 
874 void inode_set_bytes(struct inode *inode, loff_t bytes)
875 {
876 	/* Caller is here responsible for sufficient locking
877 	 * (ie. inode->i_lock) */
878 	inode->i_blocks = bytes >> 9;
879 	inode->i_bytes = bytes & 511;
880 }
881 
882 EXPORT_SYMBOL(inode_set_bytes);
883