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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
15static 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
44static 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
59static 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 */
96int __exfat_truncate(struct inode *inode)
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
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 (i_size_read(inode) > 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 if (ei->type == TYPE_FILE)
147 ei->attr |= ATTR_ARCHIVE;
148
149 /*
150 * update the directory entry
151 *
152 * If the directory entry is updated by mark_inode_dirty(), the
153 * directory entry will be written after a writeback cycle of
154 * updating the bitmap/FAT, which may result in clusters being
155 * freed but referenced by the directory entry in the event of a
156 * sudden power failure.
157 * __exfat_write_inode() is called for directory entry, bitmap
158 * and FAT to be written in a same writeback.
159 */
160 if (__exfat_write_inode(inode, inode_needs_sync(inode)))
161 return -EIO;
162
163 /* cut off from the FAT chain */
164 if (ei->flags == ALLOC_FAT_CHAIN && last_clu != EXFAT_FREE_CLUSTER &&
165 last_clu != EXFAT_EOF_CLUSTER) {
166 if (exfat_ent_set(sb, last_clu, EXFAT_EOF_CLUSTER))
167 return -EIO;
168 }
169
170 /* invalidate cache and free the clusters */
171 /* clear exfat cache */
172 exfat_cache_inval_inode(inode);
173
174 /* hint information */
175 ei->hint_bmap.off = EXFAT_EOF_CLUSTER;
176 ei->hint_bmap.clu = EXFAT_EOF_CLUSTER;
177
178 /* hint_stat will be used if this is directory. */
179 ei->hint_stat.eidx = 0;
180 ei->hint_stat.clu = ei->start_clu;
181 ei->hint_femp.eidx = EXFAT_HINT_NONE;
182
183 /* free the clusters */
184 if (exfat_free_cluster(inode, &clu))
185 return -EIO;
186
187 return 0;
188}
189
190void exfat_truncate(struct inode *inode)
191{
192 struct super_block *sb = inode->i_sb;
193 struct exfat_sb_info *sbi = EXFAT_SB(sb);
194 struct exfat_inode_info *ei = EXFAT_I(inode);
195 unsigned int blocksize = i_blocksize(inode);
196 loff_t aligned_size;
197 int err;
198
199 mutex_lock(&sbi->s_lock);
200 if (ei->start_clu == 0) {
201 /*
202 * Empty start_clu != ~0 (not allocated)
203 */
204 exfat_fs_error(sb, "tried to truncate zeroed cluster.");
205 goto write_size;
206 }
207
208 err = __exfat_truncate(inode);
209 if (err)
210 goto write_size;
211
212 inode->i_blocks = round_up(i_size_read(inode), sbi->cluster_size) >>
213 inode->i_blkbits;
214write_size:
215 aligned_size = i_size_read(inode);
216 if (aligned_size & (blocksize - 1)) {
217 aligned_size |= (blocksize - 1);
218 aligned_size++;
219 }
220
221 if (ei->i_size_ondisk > i_size_read(inode))
222 ei->i_size_ondisk = aligned_size;
223
224 if (ei->i_size_aligned > i_size_read(inode))
225 ei->i_size_aligned = aligned_size;
226 mutex_unlock(&sbi->s_lock);
227}
228
229int exfat_getattr(struct user_namespace *mnt_uerns, const struct path *path,
230 struct kstat *stat, unsigned int request_mask,
231 unsigned int query_flags)
232{
233 struct inode *inode = d_backing_inode(path->dentry);
234 struct exfat_inode_info *ei = EXFAT_I(inode);
235
236 generic_fillattr(&init_user_ns, inode, stat);
237 exfat_truncate_atime(&stat->atime);
238 stat->result_mask |= STATX_BTIME;
239 stat->btime.tv_sec = ei->i_crtime.tv_sec;
240 stat->btime.tv_nsec = ei->i_crtime.tv_nsec;
241 stat->blksize = EXFAT_SB(inode->i_sb)->cluster_size;
242 return 0;
243}
244
245int exfat_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
246 struct iattr *attr)
247{
248 struct exfat_sb_info *sbi = EXFAT_SB(dentry->d_sb);
249 struct inode *inode = dentry->d_inode;
250 unsigned int ia_valid;
251 int error;
252
253 if ((attr->ia_valid & ATTR_SIZE) &&
254 attr->ia_size > i_size_read(inode)) {
255 error = exfat_cont_expand(inode, attr->ia_size);
256 if (error || attr->ia_valid == ATTR_SIZE)
257 return error;
258 attr->ia_valid &= ~ATTR_SIZE;
259 }
260
261 /* Check for setting the inode time. */
262 ia_valid = attr->ia_valid;
263 if ((ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)) &&
264 exfat_allow_set_time(sbi, inode)) {
265 attr->ia_valid &= ~(ATTR_MTIME_SET | ATTR_ATIME_SET |
266 ATTR_TIMES_SET);
267 }
268
269 error = setattr_prepare(&init_user_ns, dentry, attr);
270 attr->ia_valid = ia_valid;
271 if (error)
272 goto out;
273
274 if (((attr->ia_valid & ATTR_UID) &&
275 !uid_eq(attr->ia_uid, sbi->options.fs_uid)) ||
276 ((attr->ia_valid & ATTR_GID) &&
277 !gid_eq(attr->ia_gid, sbi->options.fs_gid)) ||
278 ((attr->ia_valid & ATTR_MODE) &&
279 (attr->ia_mode & ~(S_IFREG | S_IFLNK | S_IFDIR | 0777)))) {
280 error = -EPERM;
281 goto out;
282 }
283
284 /*
285 * We don't return -EPERM here. Yes, strange, but this is too
286 * old behavior.
287 */
288 if (attr->ia_valid & ATTR_MODE) {
289 if (exfat_sanitize_mode(sbi, inode, &attr->ia_mode) < 0)
290 attr->ia_valid &= ~ATTR_MODE;
291 }
292
293 if (attr->ia_valid & ATTR_SIZE)
294 inode->i_mtime = inode->i_ctime = current_time(inode);
295
296 setattr_copy(&init_user_ns, inode, attr);
297 exfat_truncate_atime(&inode->i_atime);
298
299 if (attr->ia_valid & ATTR_SIZE) {
300 error = exfat_block_truncate_page(inode, attr->ia_size);
301 if (error)
302 goto out;
303
304 down_write(&EXFAT_I(inode)->truncate_lock);
305 truncate_setsize(inode, attr->ia_size);
306
307 /*
308 * __exfat_write_inode() is called from exfat_truncate(), inode
309 * is already written by it, so mark_inode_dirty() is unneeded.
310 */
311 exfat_truncate(inode);
312 up_write(&EXFAT_I(inode)->truncate_lock);
313 } else
314 mark_inode_dirty(inode);
315
316out:
317 return error;
318}
319
320static int exfat_ioctl_fitrim(struct inode *inode, unsigned long arg)
321{
322 struct fstrim_range range;
323 int ret = 0;
324
325 if (!capable(CAP_SYS_ADMIN))
326 return -EPERM;
327
328 if (!bdev_max_discard_sectors(inode->i_sb->s_bdev))
329 return -EOPNOTSUPP;
330
331 if (copy_from_user(&range, (struct fstrim_range __user *)arg, sizeof(range)))
332 return -EFAULT;
333
334 range.minlen = max_t(unsigned int, range.minlen,
335 bdev_discard_granularity(inode->i_sb->s_bdev));
336
337 ret = exfat_trim_fs(inode, &range);
338 if (ret < 0)
339 return ret;
340
341 if (copy_to_user((struct fstrim_range __user *)arg, &range, sizeof(range)))
342 return -EFAULT;
343
344 return 0;
345}
346
347long exfat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
348{
349 struct inode *inode = file_inode(filp);
350
351 switch (cmd) {
352 case FITRIM:
353 return exfat_ioctl_fitrim(inode, arg);
354 default:
355 return -ENOTTY;
356 }
357}
358
359#ifdef CONFIG_COMPAT
360long exfat_compat_ioctl(struct file *filp, unsigned int cmd,
361 unsigned long arg)
362{
363 return exfat_ioctl(filp, cmd, (unsigned long)compat_ptr(arg));
364}
365#endif
366
367int exfat_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
368{
369 struct inode *inode = filp->f_mapping->host;
370 int err;
371
372 err = __generic_file_fsync(filp, start, end, datasync);
373 if (err)
374 return err;
375
376 err = sync_blockdev(inode->i_sb->s_bdev);
377 if (err)
378 return err;
379
380 return blkdev_issue_flush(inode->i_sb->s_bdev);
381}
382
383const struct file_operations exfat_file_operations = {
384 .llseek = generic_file_llseek,
385 .read_iter = generic_file_read_iter,
386 .write_iter = generic_file_write_iter,
387 .unlocked_ioctl = exfat_ioctl,
388#ifdef CONFIG_COMPAT
389 .compat_ioctl = exfat_compat_ioctl,
390#endif
391 .mmap = generic_file_mmap,
392 .fsync = exfat_file_fsync,
393 .splice_read = generic_file_splice_read,
394 .splice_write = iter_file_splice_write,
395};
396
397const struct inode_operations exfat_file_inode_operations = {
398 .setattr = exfat_setattr,
399 .getattr = exfat_getattr,
400};