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
12 #include "exfat_raw.h"
13 #include "exfat_fs.h"
14
exfat_cont_expand(struct inode * inode,loff_t size)15 static int exfat_cont_expand(struct inode *inode, loff_t size)
16 {
17 struct address_space *mapping = inode->i_mapping;
18 loff_t start = i_size_read(inode), count = size - i_size_read(inode);
19 int err, err2;
20
21 err = generic_cont_expand_simple(inode, size);
22 if (err)
23 return err;
24
25 inode->i_ctime = inode->i_mtime = current_time(inode);
26 mark_inode_dirty(inode);
27
28 if (!IS_SYNC(inode))
29 return 0;
30
31 err = filemap_fdatawrite_range(mapping, start, start + count - 1);
32 err2 = sync_mapping_buffers(mapping);
33 if (!err)
34 err = err2;
35 err2 = write_inode_now(inode, 1);
36 if (!err)
37 err = err2;
38 if (err)
39 return err;
40
41 return filemap_fdatawait_range(mapping, start, start + count - 1);
42 }
43
exfat_allow_set_time(struct exfat_sb_info * sbi,struct inode * inode)44 static bool exfat_allow_set_time(struct exfat_sb_info *sbi, struct inode *inode)
45 {
46 mode_t allow_utime = sbi->options.allow_utime;
47
48 if (!uid_eq(current_fsuid(), inode->i_uid)) {
49 if (in_group_p(inode->i_gid))
50 allow_utime >>= 3;
51 if (allow_utime & MAY_WRITE)
52 return true;
53 }
54
55 /* use a default check */
56 return false;
57 }
58
exfat_sanitize_mode(const struct exfat_sb_info * sbi,struct inode * inode,umode_t * mode_ptr)59 static int exfat_sanitize_mode(const struct exfat_sb_info *sbi,
60 struct inode *inode, umode_t *mode_ptr)
61 {
62 mode_t i_mode, mask, perm;
63
64 i_mode = inode->i_mode;
65
66 mask = (S_ISREG(i_mode) || S_ISLNK(i_mode)) ?
67 sbi->options.fs_fmask : sbi->options.fs_dmask;
68 perm = *mode_ptr & ~(S_IFMT | mask);
69
70 /* Of the r and x bits, all (subject to umask) must be present.*/
71 if ((perm & 0555) != (i_mode & 0555))
72 return -EPERM;
73
74 if (exfat_mode_can_hold_ro(inode)) {
75 /*
76 * Of the w bits, either all (subject to umask) or none must
77 * be present.
78 */
79 if ((perm & 0222) && ((perm & 0222) != (0222 & ~mask)))
80 return -EPERM;
81 } else {
82 /*
83 * If exfat_mode_can_hold_ro(inode) is false, can't change
84 * w bits.
85 */
86 if ((perm & 0222) != (0222 & ~mask))
87 return -EPERM;
88 }
89
90 *mode_ptr &= S_IFMT | perm;
91
92 return 0;
93 }
94
95 /* resize the file length */
__exfat_truncate(struct inode * inode,loff_t new_size)96 int __exfat_truncate(struct inode *inode, loff_t new_size)
97 {
98 unsigned int num_clusters_new, num_clusters_phys;
99 unsigned int last_clu = EXFAT_FREE_CLUSTER;
100 struct exfat_chain clu;
101 struct super_block *sb = inode->i_sb;
102 struct exfat_sb_info *sbi = EXFAT_SB(sb);
103 struct exfat_inode_info *ei = EXFAT_I(inode);
104 int evict = (ei->dir.dir == DIR_DELETED) ? 1 : 0;
105
106 /* check if the given file ID is opened */
107 if (ei->type != TYPE_FILE && ei->type != TYPE_DIR)
108 return -EPERM;
109
110 exfat_set_volume_dirty(sb);
111
112 num_clusters_new = EXFAT_B_TO_CLU_ROUND_UP(i_size_read(inode), sbi);
113 num_clusters_phys = EXFAT_B_TO_CLU_ROUND_UP(ei->i_size_ondisk, sbi);
114
115 exfat_chain_set(&clu, ei->start_clu, num_clusters_phys, ei->flags);
116
117 if (new_size > 0) {
118 /*
119 * Truncate FAT chain num_clusters after the first cluster
120 * num_clusters = min(new, phys);
121 */
122 unsigned int num_clusters =
123 min(num_clusters_new, num_clusters_phys);
124
125 /*
126 * Follow FAT chain
127 * (defensive coding - works fine even with corrupted FAT table
128 */
129 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
130 clu.dir += num_clusters;
131 clu.size -= num_clusters;
132 } else {
133 while (num_clusters > 0) {
134 last_clu = clu.dir;
135 if (exfat_get_next_cluster(sb, &(clu.dir)))
136 return -EIO;
137
138 num_clusters--;
139 clu.size--;
140 }
141 }
142 } else {
143 ei->flags = ALLOC_NO_FAT_CHAIN;
144 ei->start_clu = EXFAT_EOF_CLUSTER;
145 }
146
147 i_size_write(inode, new_size);
148
149 if (ei->type == TYPE_FILE)
150 ei->attr |= ATTR_ARCHIVE;
151
152 /* update the directory entry */
153 if (!evict) {
154 struct timespec64 ts;
155 struct exfat_dentry *ep, *ep2;
156 struct exfat_entry_set_cache *es;
157 int err;
158
159 es = exfat_get_dentry_set(sb, &(ei->dir), ei->entry,
160 ES_ALL_ENTRIES);
161 if (!es)
162 return -EIO;
163 ep = exfat_get_dentry_cached(es, 0);
164 ep2 = exfat_get_dentry_cached(es, 1);
165
166 ts = current_time(inode);
167 exfat_set_entry_time(sbi, &ts,
168 &ep->dentry.file.modify_tz,
169 &ep->dentry.file.modify_time,
170 &ep->dentry.file.modify_date,
171 &ep->dentry.file.modify_time_cs);
172 ep->dentry.file.attr = cpu_to_le16(ei->attr);
173
174 /* File size should be zero if there is no cluster allocated */
175 if (ei->start_clu == EXFAT_EOF_CLUSTER) {
176 ep2->dentry.stream.valid_size = 0;
177 ep2->dentry.stream.size = 0;
178 } else {
179 ep2->dentry.stream.valid_size = cpu_to_le64(new_size);
180 ep2->dentry.stream.size = ep2->dentry.stream.valid_size;
181 }
182
183 if (new_size == 0) {
184 /* Any directory can not be truncated to zero */
185 WARN_ON(ei->type != TYPE_FILE);
186
187 ep2->dentry.stream.flags = ALLOC_FAT_CHAIN;
188 ep2->dentry.stream.start_clu = EXFAT_FREE_CLUSTER;
189 }
190
191 exfat_update_dir_chksum_with_entry_set(es);
192 err = exfat_free_dentry_set(es, inode_needs_sync(inode));
193 if (err)
194 return err;
195 }
196
197 /* cut off from the FAT chain */
198 if (ei->flags == ALLOC_FAT_CHAIN && last_clu != EXFAT_FREE_CLUSTER &&
199 last_clu != EXFAT_EOF_CLUSTER) {
200 if (exfat_ent_set(sb, last_clu, EXFAT_EOF_CLUSTER))
201 return -EIO;
202 }
203
204 /* invalidate cache and free the clusters */
205 /* clear exfat cache */
206 exfat_cache_inval_inode(inode);
207
208 /* hint information */
209 ei->hint_bmap.off = EXFAT_EOF_CLUSTER;
210 ei->hint_bmap.clu = EXFAT_EOF_CLUSTER;
211
212 /* hint_stat will be used if this is directory. */
213 ei->hint_stat.eidx = 0;
214 ei->hint_stat.clu = ei->start_clu;
215 ei->hint_femp.eidx = EXFAT_HINT_NONE;
216
217 /* free the clusters */
218 if (exfat_free_cluster(inode, &clu))
219 return -EIO;
220
221 return 0;
222 }
223
exfat_truncate(struct inode * inode,loff_t size)224 void exfat_truncate(struct inode *inode, loff_t size)
225 {
226 struct super_block *sb = inode->i_sb;
227 struct exfat_sb_info *sbi = EXFAT_SB(sb);
228 struct exfat_inode_info *ei = EXFAT_I(inode);
229 unsigned int blocksize = i_blocksize(inode);
230 loff_t aligned_size;
231 int err;
232
233 mutex_lock(&sbi->s_lock);
234 if (ei->start_clu == 0) {
235 /*
236 * Empty start_clu != ~0 (not allocated)
237 */
238 exfat_fs_error(sb, "tried to truncate zeroed cluster.");
239 goto write_size;
240 }
241
242 err = __exfat_truncate(inode, i_size_read(inode));
243 if (err)
244 goto write_size;
245
246 inode->i_ctime = inode->i_mtime = current_time(inode);
247 if (IS_DIRSYNC(inode))
248 exfat_sync_inode(inode);
249 else
250 mark_inode_dirty(inode);
251
252 inode->i_blocks = round_up(i_size_read(inode), sbi->cluster_size) >>
253 inode->i_blkbits;
254 write_size:
255 aligned_size = i_size_read(inode);
256 if (aligned_size & (blocksize - 1)) {
257 aligned_size |= (blocksize - 1);
258 aligned_size++;
259 }
260
261 if (ei->i_size_ondisk > i_size_read(inode))
262 ei->i_size_ondisk = aligned_size;
263
264 if (ei->i_size_aligned > i_size_read(inode))
265 ei->i_size_aligned = aligned_size;
266 mutex_unlock(&sbi->s_lock);
267 }
268
exfat_getattr(struct user_namespace * mnt_uerns,const struct path * path,struct kstat * stat,unsigned int request_mask,unsigned int query_flags)269 int exfat_getattr(struct user_namespace *mnt_uerns, const struct path *path,
270 struct kstat *stat, unsigned int request_mask,
271 unsigned int query_flags)
272 {
273 struct inode *inode = d_backing_inode(path->dentry);
274 struct exfat_inode_info *ei = EXFAT_I(inode);
275
276 generic_fillattr(&init_user_ns, inode, stat);
277 exfat_truncate_atime(&stat->atime);
278 stat->result_mask |= STATX_BTIME;
279 stat->btime.tv_sec = ei->i_crtime.tv_sec;
280 stat->btime.tv_nsec = ei->i_crtime.tv_nsec;
281 stat->blksize = EXFAT_SB(inode->i_sb)->cluster_size;
282 return 0;
283 }
284
exfat_setattr(struct user_namespace * mnt_userns,struct dentry * dentry,struct iattr * attr)285 int exfat_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
286 struct iattr *attr)
287 {
288 struct exfat_sb_info *sbi = EXFAT_SB(dentry->d_sb);
289 struct inode *inode = dentry->d_inode;
290 unsigned int ia_valid;
291 int error;
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(sbi, inode)) {
305 attr->ia_valid &= ~(ATTR_MTIME_SET | ATTR_ATIME_SET |
306 ATTR_TIMES_SET);
307 }
308
309 error = setattr_prepare(&init_user_ns, 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(attr->ia_uid, sbi->options.fs_uid)) ||
316 ((attr->ia_valid & ATTR_GID) &&
317 !gid_eq(attr->ia_gid, sbi->options.fs_gid)) ||
318 ((attr->ia_valid & ATTR_MODE) &&
319 (attr->ia_mode & ~(S_IFREG | S_IFLNK | S_IFDIR | 0777)))) {
320 error = -EPERM;
321 goto out;
322 }
323
324 /*
325 * We don't return -EPERM here. Yes, strange, but this is too
326 * old behavior.
327 */
328 if (attr->ia_valid & ATTR_MODE) {
329 if (exfat_sanitize_mode(sbi, inode, &attr->ia_mode) < 0)
330 attr->ia_valid &= ~ATTR_MODE;
331 }
332
333 if (attr->ia_valid & ATTR_SIZE) {
334 error = exfat_block_truncate_page(inode, attr->ia_size);
335 if (error)
336 goto out;
337
338 down_write(&EXFAT_I(inode)->truncate_lock);
339 truncate_setsize(inode, attr->ia_size);
340 exfat_truncate(inode, attr->ia_size);
341 up_write(&EXFAT_I(inode)->truncate_lock);
342 }
343
344 setattr_copy(&init_user_ns, inode, attr);
345 exfat_truncate_atime(&inode->i_atime);
346 mark_inode_dirty(inode);
347
348 out:
349 return error;
350 }
351
exfat_ioctl_fitrim(struct inode * inode,unsigned long arg)352 static int exfat_ioctl_fitrim(struct inode *inode, unsigned long arg)
353 {
354 struct fstrim_range range;
355 int ret = 0;
356
357 if (!capable(CAP_SYS_ADMIN))
358 return -EPERM;
359
360 if (!bdev_max_discard_sectors(inode->i_sb->s_bdev))
361 return -EOPNOTSUPP;
362
363 if (copy_from_user(&range, (struct fstrim_range __user *)arg, sizeof(range)))
364 return -EFAULT;
365
366 range.minlen = max_t(unsigned int, range.minlen,
367 bdev_discard_granularity(inode->i_sb->s_bdev));
368
369 ret = exfat_trim_fs(inode, &range);
370 if (ret < 0)
371 return ret;
372
373 if (copy_to_user((struct fstrim_range __user *)arg, &range, sizeof(range)))
374 return -EFAULT;
375
376 return 0;
377 }
378
exfat_ioctl(struct file * filp,unsigned int cmd,unsigned long arg)379 long exfat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
380 {
381 struct inode *inode = file_inode(filp);
382
383 switch (cmd) {
384 case FITRIM:
385 return exfat_ioctl_fitrim(inode, arg);
386 default:
387 return -ENOTTY;
388 }
389 }
390
391 #ifdef CONFIG_COMPAT
exfat_compat_ioctl(struct file * filp,unsigned int cmd,unsigned long arg)392 long exfat_compat_ioctl(struct file *filp, unsigned int cmd,
393 unsigned long arg)
394 {
395 return exfat_ioctl(filp, cmd, (unsigned long)compat_ptr(arg));
396 }
397 #endif
398
exfat_file_fsync(struct file * filp,loff_t start,loff_t end,int datasync)399 int exfat_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
400 {
401 struct inode *inode = filp->f_mapping->host;
402 int err;
403
404 err = __generic_file_fsync(filp, start, end, datasync);
405 if (err)
406 return err;
407
408 err = sync_blockdev(inode->i_sb->s_bdev);
409 if (err)
410 return err;
411
412 return blkdev_issue_flush(inode->i_sb->s_bdev);
413 }
414
415 const struct file_operations exfat_file_operations = {
416 .llseek = generic_file_llseek,
417 .read_iter = generic_file_read_iter,
418 .write_iter = generic_file_write_iter,
419 .unlocked_ioctl = exfat_ioctl,
420 #ifdef CONFIG_COMPAT
421 .compat_ioctl = exfat_compat_ioctl,
422 #endif
423 .mmap = generic_file_mmap,
424 .fsync = exfat_file_fsync,
425 .splice_read = generic_file_splice_read,
426 .splice_write = iter_file_splice_write,
427 };
428
429 const struct inode_operations exfat_file_inode_operations = {
430 .setattr = exfat_setattr,
431 .getattr = exfat_getattr,
432 };
433