xref: /linux/fs/exfat/file.c (revision 8170a99c0bc6109566f001e3a6f3c76b672c9fad)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
4  */
5 
6 #include <linux/slab.h>
7 #include <linux/compat.h>
8 #include <linux/cred.h>
9 #include <linux/buffer_head.h>
10 #include <linux/blkdev.h>
11 #include <linux/fsnotify.h>
12 #include <linux/security.h>
13 #include <linux/msdos_fs.h>
14 #include <linux/writeback.h>
15 
16 #include "exfat_raw.h"
17 #include "exfat_fs.h"
18 
exfat_cont_expand(struct inode * inode,loff_t size)19 static int exfat_cont_expand(struct inode *inode, loff_t size)
20 {
21 	int ret;
22 	unsigned int num_clusters, new_num_clusters, last_clu;
23 	struct exfat_inode_info *ei = EXFAT_I(inode);
24 	struct super_block *sb = inode->i_sb;
25 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
26 	struct exfat_chain clu;
27 
28 	ret = inode_newsize_ok(inode, size);
29 	if (ret)
30 		return ret;
31 
32 	num_clusters = EXFAT_B_TO_CLU(exfat_ondisk_size(inode), sbi);
33 	new_num_clusters = EXFAT_B_TO_CLU_ROUND_UP(size, sbi);
34 
35 	if (new_num_clusters == num_clusters)
36 		goto out;
37 
38 	if (num_clusters) {
39 		exfat_chain_set(&clu, ei->start_clu, num_clusters, ei->flags);
40 		ret = exfat_find_last_cluster(sb, &clu, &last_clu);
41 		if (ret)
42 			return ret;
43 
44 		clu.dir = last_clu + 1;
45 	} else {
46 		last_clu = EXFAT_EOF_CLUSTER;
47 		clu.dir = EXFAT_EOF_CLUSTER;
48 	}
49 
50 	clu.size = 0;
51 	clu.flags = ei->flags;
52 
53 	ret = exfat_alloc_cluster(inode, new_num_clusters - num_clusters,
54 			&clu, inode_needs_sync(inode));
55 	if (ret)
56 		return ret;
57 
58 	/* Append new clusters to chain */
59 	if (num_clusters) {
60 		if (clu.flags != ei->flags)
61 			if (exfat_chain_cont_cluster(sb, ei->start_clu, num_clusters))
62 				goto free_clu;
63 
64 		if (clu.flags == ALLOC_FAT_CHAIN)
65 			if (exfat_ent_set(sb, last_clu, clu.dir))
66 				goto free_clu;
67 	} else
68 		ei->start_clu = clu.dir;
69 
70 	ei->flags = clu.flags;
71 
72 out:
73 	inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
74 	/* Expanded range not zeroed, do not update valid_size */
75 	i_size_write(inode, size);
76 
77 	inode->i_blocks = round_up(size, sbi->cluster_size) >> 9;
78 	mark_inode_dirty(inode);
79 
80 	if (IS_SYNC(inode))
81 		return write_inode_now(inode, 1);
82 
83 	return 0;
84 
85 free_clu:
86 	exfat_free_cluster(inode, &clu);
87 	return -EIO;
88 }
89 
exfat_allow_set_time(struct mnt_idmap * idmap,struct exfat_sb_info * sbi,struct inode * inode)90 static bool exfat_allow_set_time(struct mnt_idmap *idmap,
91 				 struct exfat_sb_info *sbi, struct inode *inode)
92 {
93 	mode_t allow_utime = sbi->options.allow_utime;
94 
95 	if (!vfsuid_eq_kuid(i_uid_into_vfsuid(idmap, inode),
96 			    current_fsuid())) {
97 		if (vfsgid_in_group_p(i_gid_into_vfsgid(idmap, inode)))
98 			allow_utime >>= 3;
99 		if (allow_utime & MAY_WRITE)
100 			return true;
101 	}
102 
103 	/* use a default check */
104 	return false;
105 }
106 
exfat_sanitize_mode(const struct exfat_sb_info * sbi,struct inode * inode,umode_t * mode_ptr)107 static int exfat_sanitize_mode(const struct exfat_sb_info *sbi,
108 		struct inode *inode, umode_t *mode_ptr)
109 {
110 	mode_t i_mode, mask, perm;
111 
112 	i_mode = inode->i_mode;
113 
114 	mask = (S_ISREG(i_mode) || S_ISLNK(i_mode)) ?
115 		sbi->options.fs_fmask : sbi->options.fs_dmask;
116 	perm = *mode_ptr & ~(S_IFMT | mask);
117 
118 	/* Of the r and x bits, all (subject to umask) must be present.*/
119 	if ((perm & 0555) != (i_mode & 0555))
120 		return -EPERM;
121 
122 	if (exfat_mode_can_hold_ro(inode)) {
123 		/*
124 		 * Of the w bits, either all (subject to umask) or none must
125 		 * be present.
126 		 */
127 		if ((perm & 0222) && ((perm & 0222) != (0222 & ~mask)))
128 			return -EPERM;
129 	} else {
130 		/*
131 		 * If exfat_mode_can_hold_ro(inode) is false, can't change
132 		 * w bits.
133 		 */
134 		if ((perm & 0222) != (0222 & ~mask))
135 			return -EPERM;
136 	}
137 
138 	*mode_ptr &= S_IFMT | perm;
139 
140 	return 0;
141 }
142 
143 /* resize the file length */
__exfat_truncate(struct inode * inode)144 int __exfat_truncate(struct inode *inode)
145 {
146 	unsigned int num_clusters_new, num_clusters_phys;
147 	unsigned int last_clu = EXFAT_FREE_CLUSTER;
148 	struct exfat_chain clu;
149 	struct super_block *sb = inode->i_sb;
150 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
151 	struct exfat_inode_info *ei = EXFAT_I(inode);
152 
153 	/* check if the given file ID is opened */
154 	if (ei->type != TYPE_FILE && ei->type != TYPE_DIR)
155 		return -EPERM;
156 
157 	exfat_set_volume_dirty(sb);
158 
159 	num_clusters_new = EXFAT_B_TO_CLU_ROUND_UP(i_size_read(inode), sbi);
160 	num_clusters_phys = EXFAT_B_TO_CLU(exfat_ondisk_size(inode), sbi);
161 
162 	exfat_chain_set(&clu, ei->start_clu, num_clusters_phys, ei->flags);
163 
164 	if (i_size_read(inode) > 0) {
165 		/*
166 		 * Truncate FAT chain num_clusters after the first cluster
167 		 * num_clusters = min(new, phys);
168 		 */
169 		unsigned int num_clusters =
170 			min(num_clusters_new, num_clusters_phys);
171 
172 		/*
173 		 * Follow FAT chain
174 		 * (defensive coding - works fine even with corrupted FAT table
175 		 */
176 		if (clu.flags == ALLOC_NO_FAT_CHAIN) {
177 			clu.dir += num_clusters;
178 			clu.size -= num_clusters;
179 		} else {
180 			while (num_clusters > 0) {
181 				last_clu = clu.dir;
182 				if (exfat_get_next_cluster(sb, &(clu.dir)))
183 					return -EIO;
184 
185 				num_clusters--;
186 				clu.size--;
187 			}
188 		}
189 	} else {
190 		ei->flags = ALLOC_NO_FAT_CHAIN;
191 		ei->start_clu = EXFAT_EOF_CLUSTER;
192 	}
193 
194 	if (i_size_read(inode) < ei->valid_size)
195 		ei->valid_size = i_size_read(inode);
196 
197 	if (ei->type == TYPE_FILE)
198 		ei->attr |= EXFAT_ATTR_ARCHIVE;
199 
200 	/*
201 	 * update the directory entry
202 	 *
203 	 * If the directory entry is updated by mark_inode_dirty(), the
204 	 * directory entry will be written after a writeback cycle of
205 	 * updating the bitmap/FAT, which may result in clusters being
206 	 * freed but referenced by the directory entry in the event of a
207 	 * sudden power failure.
208 	 * __exfat_write_inode() is called for directory entry, bitmap
209 	 * and FAT to be written in a same writeback.
210 	 */
211 	if (__exfat_write_inode(inode, inode_needs_sync(inode)))
212 		return -EIO;
213 
214 	/* cut off from the FAT chain */
215 	if (ei->flags == ALLOC_FAT_CHAIN && last_clu != EXFAT_FREE_CLUSTER &&
216 			last_clu != EXFAT_EOF_CLUSTER) {
217 		if (exfat_ent_set(sb, last_clu, EXFAT_EOF_CLUSTER))
218 			return -EIO;
219 	}
220 
221 	/* invalidate cache and free the clusters */
222 	/* clear exfat cache */
223 	exfat_cache_inval_inode(inode);
224 
225 	/* hint information */
226 	ei->hint_bmap.off = EXFAT_EOF_CLUSTER;
227 	ei->hint_bmap.clu = EXFAT_EOF_CLUSTER;
228 
229 	/* hint_stat will be used if this is directory. */
230 	ei->hint_stat.eidx = 0;
231 	ei->hint_stat.clu = ei->start_clu;
232 	ei->hint_femp.eidx = EXFAT_HINT_NONE;
233 
234 	/* free the clusters */
235 	if (exfat_free_cluster(inode, &clu))
236 		return -EIO;
237 
238 	return 0;
239 }
240 
exfat_truncate(struct inode * inode)241 void exfat_truncate(struct inode *inode)
242 {
243 	struct super_block *sb = inode->i_sb;
244 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
245 	struct exfat_inode_info *ei = EXFAT_I(inode);
246 	int err;
247 
248 	mutex_lock(&sbi->s_lock);
249 	if (ei->start_clu == 0) {
250 		/*
251 		 * Empty start_clu != ~0 (not allocated)
252 		 */
253 		exfat_fs_error(sb, "tried to truncate zeroed cluster.");
254 		goto write_size;
255 	}
256 
257 	err = __exfat_truncate(inode);
258 	if (err)
259 		goto write_size;
260 
261 	inode->i_blocks = round_up(i_size_read(inode), sbi->cluster_size) >> 9;
262 write_size:
263 	mutex_unlock(&sbi->s_lock);
264 }
265 
exfat_getattr(struct mnt_idmap * idmap,const struct path * path,struct kstat * stat,unsigned int request_mask,unsigned int query_flags)266 int exfat_getattr(struct mnt_idmap *idmap, const struct path *path,
267 		  struct kstat *stat, unsigned int request_mask,
268 		  unsigned int query_flags)
269 {
270 	struct inode *inode = d_backing_inode(path->dentry);
271 	struct exfat_inode_info *ei = EXFAT_I(inode);
272 
273 	generic_fillattr(idmap, request_mask, inode, stat);
274 	exfat_truncate_atime(&stat->atime);
275 	stat->result_mask |= STATX_BTIME;
276 	stat->btime.tv_sec = ei->i_crtime.tv_sec;
277 	stat->btime.tv_nsec = ei->i_crtime.tv_nsec;
278 	stat->blksize = EXFAT_SB(inode->i_sb)->cluster_size;
279 	return 0;
280 }
281 
exfat_setattr(struct mnt_idmap * idmap,struct dentry * dentry,struct iattr * attr)282 int exfat_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
283 		  struct iattr *attr)
284 {
285 	struct exfat_sb_info *sbi = EXFAT_SB(dentry->d_sb);
286 	struct inode *inode = dentry->d_inode;
287 	unsigned int ia_valid;
288 	int error;
289 
290 	if (unlikely(exfat_forced_shutdown(inode->i_sb)))
291 		return -EIO;
292 
293 	if ((attr->ia_valid & ATTR_SIZE) &&
294 	    attr->ia_size > i_size_read(inode)) {
295 		error = exfat_cont_expand(inode, attr->ia_size);
296 		if (error || attr->ia_valid == ATTR_SIZE)
297 			return error;
298 		attr->ia_valid &= ~ATTR_SIZE;
299 	}
300 
301 	/* Check for setting the inode time. */
302 	ia_valid = attr->ia_valid;
303 	if ((ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)) &&
304 	    exfat_allow_set_time(idmap, sbi, inode)) {
305 		attr->ia_valid &= ~(ATTR_MTIME_SET | ATTR_ATIME_SET |
306 				ATTR_TIMES_SET);
307 	}
308 
309 	error = setattr_prepare(idmap, dentry, attr);
310 	attr->ia_valid = ia_valid;
311 	if (error)
312 		goto out;
313 
314 	if (((attr->ia_valid & ATTR_UID) &&
315 	      (!uid_eq(from_vfsuid(idmap, i_user_ns(inode), attr->ia_vfsuid),
316 	       sbi->options.fs_uid))) ||
317 	    ((attr->ia_valid & ATTR_GID) &&
318 	      (!gid_eq(from_vfsgid(idmap, i_user_ns(inode), attr->ia_vfsgid),
319 	       sbi->options.fs_gid))) ||
320 	    ((attr->ia_valid & ATTR_MODE) &&
321 	     (attr->ia_mode & ~(S_IFREG | S_IFLNK | S_IFDIR | 0777)))) {
322 		error = -EPERM;
323 		goto out;
324 	}
325 
326 	/*
327 	 * We don't return -EPERM here. Yes, strange, but this is too
328 	 * old behavior.
329 	 */
330 	if (attr->ia_valid & ATTR_MODE) {
331 		if (exfat_sanitize_mode(sbi, inode, &attr->ia_mode) < 0)
332 			attr->ia_valid &= ~ATTR_MODE;
333 	}
334 
335 	if (attr->ia_valid & ATTR_SIZE)
336 		inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
337 
338 	setattr_copy(idmap, inode, attr);
339 	exfat_truncate_inode_atime(inode);
340 
341 	if (attr->ia_valid & ATTR_SIZE) {
342 		error = exfat_block_truncate_page(inode, attr->ia_size);
343 		if (error)
344 			goto out;
345 
346 		down_write(&EXFAT_I(inode)->truncate_lock);
347 		truncate_setsize(inode, attr->ia_size);
348 
349 		/*
350 		 * __exfat_write_inode() is called from exfat_truncate(), inode
351 		 * is already written by it, so mark_inode_dirty() is unneeded.
352 		 */
353 		exfat_truncate(inode);
354 		up_write(&EXFAT_I(inode)->truncate_lock);
355 	} else
356 		mark_inode_dirty(inode);
357 
358 out:
359 	return error;
360 }
361 
362 /*
363  * modified ioctls from fat/file.c by Welmer Almesberger
364  */
exfat_ioctl_get_attributes(struct inode * inode,u32 __user * user_attr)365 static int exfat_ioctl_get_attributes(struct inode *inode, u32 __user *user_attr)
366 {
367 	u32 attr;
368 
369 	inode_lock_shared(inode);
370 	attr = exfat_make_attr(inode);
371 	inode_unlock_shared(inode);
372 
373 	return put_user(attr, user_attr);
374 }
375 
exfat_ioctl_set_attributes(struct file * file,u32 __user * user_attr)376 static int exfat_ioctl_set_attributes(struct file *file, u32 __user *user_attr)
377 {
378 	struct inode *inode = file_inode(file);
379 	struct exfat_sb_info *sbi = EXFAT_SB(inode->i_sb);
380 	int is_dir = S_ISDIR(inode->i_mode);
381 	u32 attr, oldattr;
382 	struct iattr ia;
383 	int err;
384 
385 	err = get_user(attr, user_attr);
386 	if (err)
387 		goto out;
388 
389 	err = mnt_want_write_file(file);
390 	if (err)
391 		goto out;
392 	inode_lock(inode);
393 
394 	oldattr = exfat_make_attr(inode);
395 
396 	/*
397 	 * Mask attributes so we don't set reserved fields.
398 	 */
399 	attr &= (EXFAT_ATTR_READONLY | EXFAT_ATTR_HIDDEN | EXFAT_ATTR_SYSTEM |
400 		 EXFAT_ATTR_ARCHIVE);
401 	attr |= (is_dir ? EXFAT_ATTR_SUBDIR : 0);
402 
403 	/* Equivalent to a chmod() */
404 	ia.ia_valid = ATTR_MODE | ATTR_CTIME;
405 	ia.ia_ctime = current_time(inode);
406 	if (is_dir)
407 		ia.ia_mode = exfat_make_mode(sbi, attr, 0777);
408 	else
409 		ia.ia_mode = exfat_make_mode(sbi, attr, 0666 | (inode->i_mode & 0111));
410 
411 	/* The root directory has no attributes */
412 	if (inode->i_ino == EXFAT_ROOT_INO && attr != EXFAT_ATTR_SUBDIR) {
413 		err = -EINVAL;
414 		goto out_unlock_inode;
415 	}
416 
417 	if (((attr | oldattr) & EXFAT_ATTR_SYSTEM) &&
418 	    !capable(CAP_LINUX_IMMUTABLE)) {
419 		err = -EPERM;
420 		goto out_unlock_inode;
421 	}
422 
423 	/*
424 	 * The security check is questionable...  We single
425 	 * out the RO attribute for checking by the security
426 	 * module, just because it maps to a file mode.
427 	 */
428 	err = security_inode_setattr(file_mnt_idmap(file),
429 				     file->f_path.dentry, &ia);
430 	if (err)
431 		goto out_unlock_inode;
432 
433 	/* This MUST be done before doing anything irreversible... */
434 	err = exfat_setattr(file_mnt_idmap(file), file->f_path.dentry, &ia);
435 	if (err)
436 		goto out_unlock_inode;
437 
438 	fsnotify_change(file->f_path.dentry, ia.ia_valid);
439 
440 	exfat_save_attr(inode, attr);
441 	mark_inode_dirty(inode);
442 out_unlock_inode:
443 	inode_unlock(inode);
444 	mnt_drop_write_file(file);
445 out:
446 	return err;
447 }
448 
exfat_ioctl_fitrim(struct inode * inode,unsigned long arg)449 static int exfat_ioctl_fitrim(struct inode *inode, unsigned long arg)
450 {
451 	struct fstrim_range range;
452 	int ret = 0;
453 
454 	if (!capable(CAP_SYS_ADMIN))
455 		return -EPERM;
456 
457 	if (!bdev_max_discard_sectors(inode->i_sb->s_bdev))
458 		return -EOPNOTSUPP;
459 
460 	if (copy_from_user(&range, (struct fstrim_range __user *)arg, sizeof(range)))
461 		return -EFAULT;
462 
463 	range.minlen = max_t(unsigned int, range.minlen,
464 				bdev_discard_granularity(inode->i_sb->s_bdev));
465 
466 	ret = exfat_trim_fs(inode, &range);
467 	if (ret < 0)
468 		return ret;
469 
470 	if (copy_to_user((struct fstrim_range __user *)arg, &range, sizeof(range)))
471 		return -EFAULT;
472 
473 	return 0;
474 }
475 
exfat_ioctl_shutdown(struct super_block * sb,unsigned long arg)476 static int exfat_ioctl_shutdown(struct super_block *sb, unsigned long arg)
477 {
478 	u32 flags;
479 
480 	if (!capable(CAP_SYS_ADMIN))
481 		return -EPERM;
482 
483 	if (get_user(flags, (__u32 __user *)arg))
484 		return -EFAULT;
485 
486 	return exfat_force_shutdown(sb, flags);
487 }
488 
exfat_ioctl(struct file * filp,unsigned int cmd,unsigned long arg)489 long exfat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
490 {
491 	struct inode *inode = file_inode(filp);
492 	u32 __user *user_attr = (u32 __user *)arg;
493 
494 	switch (cmd) {
495 	case FAT_IOCTL_GET_ATTRIBUTES:
496 		return exfat_ioctl_get_attributes(inode, user_attr);
497 	case FAT_IOCTL_SET_ATTRIBUTES:
498 		return exfat_ioctl_set_attributes(filp, user_attr);
499 	case EXFAT_IOC_SHUTDOWN:
500 		return exfat_ioctl_shutdown(inode->i_sb, arg);
501 	case FITRIM:
502 		return exfat_ioctl_fitrim(inode, arg);
503 	default:
504 		return -ENOTTY;
505 	}
506 }
507 
508 #ifdef CONFIG_COMPAT
exfat_compat_ioctl(struct file * filp,unsigned int cmd,unsigned long arg)509 long exfat_compat_ioctl(struct file *filp, unsigned int cmd,
510 				unsigned long arg)
511 {
512 	return exfat_ioctl(filp, cmd, (unsigned long)compat_ptr(arg));
513 }
514 #endif
515 
exfat_file_fsync(struct file * filp,loff_t start,loff_t end,int datasync)516 int exfat_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
517 {
518 	struct inode *inode = filp->f_mapping->host;
519 	int err;
520 
521 	if (unlikely(exfat_forced_shutdown(inode->i_sb)))
522 		return -EIO;
523 
524 	err = __generic_file_fsync(filp, start, end, datasync);
525 	if (err)
526 		return err;
527 
528 	err = sync_blockdev(inode->i_sb->s_bdev);
529 	if (err)
530 		return err;
531 
532 	return blkdev_issue_flush(inode->i_sb->s_bdev);
533 }
534 
exfat_extend_valid_size(struct file * file,loff_t new_valid_size)535 static int exfat_extend_valid_size(struct file *file, loff_t new_valid_size)
536 {
537 	int err;
538 	loff_t pos;
539 	struct inode *inode = file_inode(file);
540 	struct exfat_inode_info *ei = EXFAT_I(inode);
541 	struct address_space *mapping = inode->i_mapping;
542 	const struct address_space_operations *ops = mapping->a_ops;
543 
544 	pos = ei->valid_size;
545 	while (pos < new_valid_size) {
546 		u32 len;
547 		struct folio *folio;
548 
549 		len = PAGE_SIZE - (pos & (PAGE_SIZE - 1));
550 		if (pos + len > new_valid_size)
551 			len = new_valid_size - pos;
552 
553 		err = ops->write_begin(file, mapping, pos, len, &folio, NULL);
554 		if (err)
555 			goto out;
556 
557 		err = ops->write_end(file, mapping, pos, len, len, folio, NULL);
558 		if (err < 0)
559 			goto out;
560 		pos += len;
561 
562 		balance_dirty_pages_ratelimited(mapping);
563 		cond_resched();
564 	}
565 
566 out:
567 	return err;
568 }
569 
exfat_file_write_iter(struct kiocb * iocb,struct iov_iter * iter)570 static ssize_t exfat_file_write_iter(struct kiocb *iocb, struct iov_iter *iter)
571 {
572 	ssize_t ret;
573 	struct file *file = iocb->ki_filp;
574 	struct inode *inode = file_inode(file);
575 	struct exfat_inode_info *ei = EXFAT_I(inode);
576 	loff_t pos = iocb->ki_pos;
577 	loff_t valid_size;
578 
579 	inode_lock(inode);
580 
581 	valid_size = ei->valid_size;
582 
583 	ret = generic_write_checks(iocb, iter);
584 	if (ret < 0)
585 		goto unlock;
586 
587 	if (iocb->ki_flags & IOCB_DIRECT) {
588 		unsigned long align = pos | iov_iter_alignment(iter);
589 
590 		if (!IS_ALIGNED(align, i_blocksize(inode)) &&
591 		    !IS_ALIGNED(align, bdev_logical_block_size(inode->i_sb->s_bdev))) {
592 			ret = -EINVAL;
593 			goto unlock;
594 		}
595 	}
596 
597 	if (pos > valid_size) {
598 		ret = exfat_extend_valid_size(file, pos);
599 		if (ret < 0 && ret != -ENOSPC) {
600 			exfat_err(inode->i_sb,
601 				"write: fail to zero from %llu to %llu(%zd)",
602 				valid_size, pos, ret);
603 		}
604 		if (ret < 0)
605 			goto unlock;
606 	}
607 
608 	ret = __generic_file_write_iter(iocb, iter);
609 	if (ret < 0)
610 		goto unlock;
611 
612 	inode_unlock(inode);
613 
614 	if (pos > valid_size)
615 		pos = valid_size;
616 
617 	if (iocb_is_dsync(iocb) && iocb->ki_pos > pos) {
618 		ssize_t err = vfs_fsync_range(file, pos, iocb->ki_pos - 1,
619 				iocb->ki_flags & IOCB_SYNC);
620 		if (err < 0)
621 			return err;
622 	}
623 
624 	return ret;
625 
626 unlock:
627 	inode_unlock(inode);
628 
629 	return ret;
630 }
631 
exfat_page_mkwrite(struct vm_fault * vmf)632 static vm_fault_t exfat_page_mkwrite(struct vm_fault *vmf)
633 {
634 	int err;
635 	struct vm_area_struct *vma = vmf->vma;
636 	struct file *file = vma->vm_file;
637 	struct inode *inode = file_inode(file);
638 	struct exfat_inode_info *ei = EXFAT_I(inode);
639 	loff_t start, end;
640 
641 	if (!inode_trylock(inode))
642 		return VM_FAULT_RETRY;
643 
644 	start = ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
645 	end = min_t(loff_t, i_size_read(inode),
646 			start + vma->vm_end - vma->vm_start);
647 
648 	if (ei->valid_size < end) {
649 		err = exfat_extend_valid_size(file, end);
650 		if (err < 0) {
651 			inode_unlock(inode);
652 			return vmf_fs_error(err);
653 		}
654 	}
655 
656 	inode_unlock(inode);
657 
658 	return filemap_page_mkwrite(vmf);
659 }
660 
661 static const struct vm_operations_struct exfat_file_vm_ops = {
662 	.fault		= filemap_fault,
663 	.map_pages	= filemap_map_pages,
664 	.page_mkwrite	= exfat_page_mkwrite,
665 };
666 
exfat_file_mmap(struct file * file,struct vm_area_struct * vma)667 static int exfat_file_mmap(struct file *file, struct vm_area_struct *vma)
668 {
669 	file_accessed(file);
670 	vma->vm_ops = &exfat_file_vm_ops;
671 	return 0;
672 }
673 
674 const struct file_operations exfat_file_operations = {
675 	.llseek		= generic_file_llseek,
676 	.read_iter	= generic_file_read_iter,
677 	.write_iter	= exfat_file_write_iter,
678 	.unlocked_ioctl = exfat_ioctl,
679 #ifdef CONFIG_COMPAT
680 	.compat_ioctl = exfat_compat_ioctl,
681 #endif
682 	.mmap		= exfat_file_mmap,
683 	.fsync		= exfat_file_fsync,
684 	.splice_read	= filemap_splice_read,
685 	.splice_write	= iter_file_splice_write,
686 };
687 
688 const struct inode_operations exfat_file_inode_operations = {
689 	.setattr     = exfat_setattr,
690 	.getattr     = exfat_getattr,
691 };
692