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/cred.h>
8 #include <linux/buffer_head.h>
9 #include <linux/blkdev.h>
10
11 #include "exfat_raw.h"
12 #include "exfat_fs.h"
13
exfat_cont_expand(struct inode * inode,loff_t size)14 static int exfat_cont_expand(struct inode *inode, loff_t size)
15 {
16 struct address_space *mapping = inode->i_mapping;
17 loff_t start = i_size_read(inode), count = size - i_size_read(inode);
18 int err, err2;
19
20 err = generic_cont_expand_simple(inode, size);
21 if (err)
22 return err;
23
24 inode->i_ctime = inode->i_mtime = current_time(inode);
25 mark_inode_dirty(inode);
26
27 if (!IS_SYNC(inode))
28 return 0;
29
30 err = filemap_fdatawrite_range(mapping, start, start + count - 1);
31 err2 = sync_mapping_buffers(mapping);
32 if (!err)
33 err = err2;
34 err2 = write_inode_now(inode, 1);
35 if (!err)
36 err = err2;
37 if (err)
38 return err;
39
40 return filemap_fdatawait_range(mapping, start, start + count - 1);
41 }
42
exfat_allow_set_time(struct exfat_sb_info * sbi,struct inode * inode)43 static bool exfat_allow_set_time(struct exfat_sb_info *sbi, struct inode *inode)
44 {
45 mode_t allow_utime = sbi->options.allow_utime;
46
47 if (!uid_eq(current_fsuid(), inode->i_uid)) {
48 if (in_group_p(inode->i_gid))
49 allow_utime >>= 3;
50 if (allow_utime & MAY_WRITE)
51 return true;
52 }
53
54 /* use a default check */
55 return false;
56 }
57
exfat_sanitize_mode(const struct exfat_sb_info * sbi,struct inode * inode,umode_t * mode_ptr)58 static int exfat_sanitize_mode(const struct exfat_sb_info *sbi,
59 struct inode *inode, umode_t *mode_ptr)
60 {
61 mode_t i_mode, mask, perm;
62
63 i_mode = inode->i_mode;
64
65 mask = (S_ISREG(i_mode) || S_ISLNK(i_mode)) ?
66 sbi->options.fs_fmask : sbi->options.fs_dmask;
67 perm = *mode_ptr & ~(S_IFMT | mask);
68
69 /* Of the r and x bits, all (subject to umask) must be present.*/
70 if ((perm & 0555) != (i_mode & 0555))
71 return -EPERM;
72
73 if (exfat_mode_can_hold_ro(inode)) {
74 /*
75 * Of the w bits, either all (subject to umask) or none must
76 * be present.
77 */
78 if ((perm & 0222) && ((perm & 0222) != (0222 & ~mask)))
79 return -EPERM;
80 } else {
81 /*
82 * If exfat_mode_can_hold_ro(inode) is false, can't change
83 * w bits.
84 */
85 if ((perm & 0222) != (0222 & ~mask))
86 return -EPERM;
87 }
88
89 *mode_ptr &= S_IFMT | perm;
90
91 return 0;
92 }
93
94 /* resize the file length */
__exfat_truncate(struct inode * inode,loff_t new_size)95 int __exfat_truncate(struct inode *inode, loff_t new_size)
96 {
97 unsigned int num_clusters_new, num_clusters_phys;
98 unsigned int last_clu = EXFAT_FREE_CLUSTER;
99 struct exfat_chain clu;
100 struct super_block *sb = inode->i_sb;
101 struct exfat_sb_info *sbi = EXFAT_SB(sb);
102 struct exfat_inode_info *ei = EXFAT_I(inode);
103 int evict = (ei->dir.dir == DIR_DELETED) ? 1 : 0;
104
105 /* check if the given file ID is opened */
106 if (ei->type != TYPE_FILE && ei->type != TYPE_DIR)
107 return -EPERM;
108
109 exfat_set_volume_dirty(sb);
110
111 num_clusters_new = EXFAT_B_TO_CLU_ROUND_UP(i_size_read(inode), sbi);
112 num_clusters_phys = EXFAT_B_TO_CLU_ROUND_UP(ei->i_size_ondisk, sbi);
113
114 exfat_chain_set(&clu, ei->start_clu, num_clusters_phys, ei->flags);
115
116 if (new_size > 0) {
117 /*
118 * Truncate FAT chain num_clusters after the first cluster
119 * num_clusters = min(new, phys);
120 */
121 unsigned int num_clusters =
122 min(num_clusters_new, num_clusters_phys);
123
124 /*
125 * Follow FAT chain
126 * (defensive coding - works fine even with corrupted FAT table
127 */
128 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
129 clu.dir += num_clusters;
130 clu.size -= num_clusters;
131 } else {
132 while (num_clusters > 0) {
133 last_clu = clu.dir;
134 if (exfat_get_next_cluster(sb, &(clu.dir)))
135 return -EIO;
136
137 num_clusters--;
138 clu.size--;
139 }
140 }
141 } else {
142 ei->flags = ALLOC_NO_FAT_CHAIN;
143 ei->start_clu = EXFAT_EOF_CLUSTER;
144 }
145
146 i_size_write(inode, new_size);
147
148 if (ei->type == TYPE_FILE)
149 ei->attr |= ATTR_ARCHIVE;
150
151 /* update the directory entry */
152 if (!evict) {
153 struct timespec64 ts;
154 struct exfat_dentry *ep, *ep2;
155 struct exfat_entry_set_cache *es;
156 int err;
157
158 es = exfat_get_dentry_set(sb, &(ei->dir), ei->entry,
159 ES_ALL_ENTRIES);
160 if (!es)
161 return -EIO;
162 ep = exfat_get_dentry_cached(es, 0);
163 ep2 = exfat_get_dentry_cached(es, 1);
164
165 ts = current_time(inode);
166 exfat_set_entry_time(sbi, &ts,
167 &ep->dentry.file.modify_tz,
168 &ep->dentry.file.modify_time,
169 &ep->dentry.file.modify_date,
170 &ep->dentry.file.modify_time_cs);
171 ep->dentry.file.attr = cpu_to_le16(ei->attr);
172
173 /* File size should be zero if there is no cluster allocated */
174 if (ei->start_clu == EXFAT_EOF_CLUSTER) {
175 ep2->dentry.stream.valid_size = 0;
176 ep2->dentry.stream.size = 0;
177 } else {
178 ep2->dentry.stream.valid_size = cpu_to_le64(new_size);
179 ep2->dentry.stream.size = ep2->dentry.stream.valid_size;
180 }
181
182 if (new_size == 0) {
183 /* Any directory can not be truncated to zero */
184 WARN_ON(ei->type != TYPE_FILE);
185
186 ep2->dentry.stream.flags = ALLOC_FAT_CHAIN;
187 ep2->dentry.stream.start_clu = EXFAT_FREE_CLUSTER;
188 }
189
190 exfat_update_dir_chksum_with_entry_set(es);
191 err = exfat_free_dentry_set(es, inode_needs_sync(inode));
192 if (err)
193 return err;
194 }
195
196 /* cut off from the FAT chain */
197 if (ei->flags == ALLOC_FAT_CHAIN && last_clu != EXFAT_FREE_CLUSTER &&
198 last_clu != EXFAT_EOF_CLUSTER) {
199 if (exfat_ent_set(sb, last_clu, EXFAT_EOF_CLUSTER))
200 return -EIO;
201 }
202
203 /* invalidate cache and free the clusters */
204 /* clear exfat cache */
205 exfat_cache_inval_inode(inode);
206
207 /* hint information */
208 ei->hint_bmap.off = EXFAT_EOF_CLUSTER;
209 ei->hint_bmap.clu = EXFAT_EOF_CLUSTER;
210
211 /* hint_stat will be used if this is directory. */
212 ei->hint_stat.eidx = 0;
213 ei->hint_stat.clu = ei->start_clu;
214 ei->hint_femp.eidx = EXFAT_HINT_NONE;
215
216 /* free the clusters */
217 if (exfat_free_cluster(inode, &clu))
218 return -EIO;
219
220 exfat_clear_volume_dirty(sb);
221
222 return 0;
223 }
224
exfat_truncate(struct inode * inode,loff_t size)225 void exfat_truncate(struct inode *inode, loff_t size)
226 {
227 struct super_block *sb = inode->i_sb;
228 struct exfat_sb_info *sbi = EXFAT_SB(sb);
229 struct exfat_inode_info *ei = EXFAT_I(inode);
230 unsigned int blocksize = i_blocksize(inode);
231 loff_t aligned_size;
232 int err;
233
234 mutex_lock(&sbi->s_lock);
235 if (ei->start_clu == 0) {
236 /*
237 * Empty start_clu != ~0 (not allocated)
238 */
239 exfat_fs_error(sb, "tried to truncate zeroed cluster.");
240 goto write_size;
241 }
242
243 err = __exfat_truncate(inode, i_size_read(inode));
244 if (err)
245 goto write_size;
246
247 inode->i_ctime = inode->i_mtime = current_time(inode);
248 if (IS_DIRSYNC(inode))
249 exfat_sync_inode(inode);
250 else
251 mark_inode_dirty(inode);
252
253 inode->i_blocks = round_up(i_size_read(inode), sbi->cluster_size) >> 9;
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(const struct path * path,struct kstat * stat,unsigned int request_mask,unsigned int query_flags)269 int exfat_getattr(const struct path *path, struct kstat *stat,
270 unsigned int request_mask, unsigned int query_flags)
271 {
272 struct inode *inode = d_backing_inode(path->dentry);
273 struct exfat_inode_info *ei = EXFAT_I(inode);
274
275 generic_fillattr(inode, stat);
276 exfat_truncate_atime(&stat->atime);
277 stat->result_mask |= STATX_BTIME;
278 stat->btime.tv_sec = ei->i_crtime.tv_sec;
279 stat->btime.tv_nsec = ei->i_crtime.tv_nsec;
280 stat->blksize = EXFAT_SB(inode->i_sb)->cluster_size;
281 return 0;
282 }
283
exfat_setattr(struct dentry * dentry,struct iattr * attr)284 int exfat_setattr(struct dentry *dentry, struct iattr *attr)
285 {
286 struct exfat_sb_info *sbi = EXFAT_SB(dentry->d_sb);
287 struct inode *inode = dentry->d_inode;
288 unsigned int ia_valid;
289 int error;
290
291 if ((attr->ia_valid & ATTR_SIZE) &&
292 attr->ia_size > i_size_read(inode)) {
293 error = exfat_cont_expand(inode, attr->ia_size);
294 if (error || attr->ia_valid == ATTR_SIZE)
295 return error;
296 attr->ia_valid &= ~ATTR_SIZE;
297 }
298
299 /* Check for setting the inode time. */
300 ia_valid = attr->ia_valid;
301 if ((ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)) &&
302 exfat_allow_set_time(sbi, inode)) {
303 attr->ia_valid &= ~(ATTR_MTIME_SET | ATTR_ATIME_SET |
304 ATTR_TIMES_SET);
305 }
306
307 error = setattr_prepare(dentry, attr);
308 attr->ia_valid = ia_valid;
309 if (error)
310 goto out;
311
312 if (((attr->ia_valid & ATTR_UID) &&
313 !uid_eq(attr->ia_uid, sbi->options.fs_uid)) ||
314 ((attr->ia_valid & ATTR_GID) &&
315 !gid_eq(attr->ia_gid, sbi->options.fs_gid)) ||
316 ((attr->ia_valid & ATTR_MODE) &&
317 (attr->ia_mode & ~(S_IFREG | S_IFLNK | S_IFDIR | 0777)))) {
318 error = -EPERM;
319 goto out;
320 }
321
322 /*
323 * We don't return -EPERM here. Yes, strange, but this is too
324 * old behavior.
325 */
326 if (attr->ia_valid & ATTR_MODE) {
327 if (exfat_sanitize_mode(sbi, inode, &attr->ia_mode) < 0)
328 attr->ia_valid &= ~ATTR_MODE;
329 }
330
331 if (attr->ia_valid & ATTR_SIZE) {
332 error = exfat_block_truncate_page(inode, attr->ia_size);
333 if (error)
334 goto out;
335
336 down_write(&EXFAT_I(inode)->truncate_lock);
337 truncate_setsize(inode, attr->ia_size);
338 exfat_truncate(inode, attr->ia_size);
339 up_write(&EXFAT_I(inode)->truncate_lock);
340 }
341
342 setattr_copy(inode, attr);
343 exfat_truncate_atime(&inode->i_atime);
344 mark_inode_dirty(inode);
345
346 out:
347 return error;
348 }
349
exfat_file_fsync(struct file * filp,loff_t start,loff_t end,int datasync)350 int exfat_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
351 {
352 struct inode *inode = filp->f_mapping->host;
353 int err;
354
355 err = __generic_file_fsync(filp, start, end, datasync);
356 if (err)
357 return err;
358
359 err = sync_blockdev(inode->i_sb->s_bdev);
360 if (err)
361 return err;
362
363 return blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL);
364 }
365
366 const struct file_operations exfat_file_operations = {
367 .llseek = generic_file_llseek,
368 .read_iter = generic_file_read_iter,
369 .write_iter = generic_file_write_iter,
370 .mmap = generic_file_mmap,
371 .fsync = exfat_file_fsync,
372 .splice_read = generic_file_splice_read,
373 .splice_write = iter_file_splice_write,
374 };
375
376 const struct inode_operations exfat_file_inode_operations = {
377 .setattr = exfat_setattr,
378 .getattr = exfat_getattr,
379 };
380