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

source code of linux/fs/exfat/file.c