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/bio.h>
9 #include <linux/buffer_head.h>
10
11 #include "exfat_raw.h"
12 #include "exfat_fs.h"
13
exfat_extract_uni_name(struct exfat_dentry * ep,unsigned short * uniname)14 static int exfat_extract_uni_name(struct exfat_dentry *ep,
15 unsigned short *uniname)
16 {
17 int i, len = 0;
18
19 for (i = 0; i < EXFAT_FILE_NAME_LEN; i++) {
20 *uniname = le16_to_cpu(ep->dentry.name.unicode_0_14[i]);
21 if (*uniname == 0x0)
22 return len;
23 uniname++;
24 len++;
25 }
26
27 *uniname = 0x0;
28 return len;
29
30 }
31
exfat_get_uniname_from_ext_entry(struct super_block * sb,struct exfat_chain * p_dir,int entry,unsigned short * uniname)32 static int exfat_get_uniname_from_ext_entry(struct super_block *sb,
33 struct exfat_chain *p_dir, int entry, unsigned short *uniname)
34 {
35 int i, err;
36 struct exfat_entry_set_cache es;
37 unsigned int uni_len = 0, len;
38
39 err = exfat_get_dentry_set(&es, sb, p_dir, entry, ES_ALL_ENTRIES);
40 if (err)
41 return err;
42
43 /*
44 * First entry : file entry
45 * Second entry : stream-extension entry
46 * Third entry : first file-name entry
47 * So, the index of first file-name dentry should start from 2.
48 */
49 for (i = ES_IDX_FIRST_FILENAME; i < es.num_entries; i++) {
50 struct exfat_dentry *ep = exfat_get_dentry_cached(&es, i);
51
52 /* end of name entry */
53 if (exfat_get_entry_type(ep) != TYPE_EXTEND)
54 break;
55
56 len = exfat_extract_uni_name(ep, uniname);
57 uni_len += len;
58 if (len != EXFAT_FILE_NAME_LEN || uni_len >= MAX_NAME_LENGTH)
59 break;
60 uniname += EXFAT_FILE_NAME_LEN;
61 }
62
63 exfat_put_dentry_set(&es, false);
64 return 0;
65 }
66
67 /* read a directory entry from the opened directory */
exfat_readdir(struct inode * inode,loff_t * cpos,struct exfat_dir_entry * dir_entry)68 static int exfat_readdir(struct inode *inode, loff_t *cpos, struct exfat_dir_entry *dir_entry)
69 {
70 int i, dentries_per_clu, num_ext, err;
71 unsigned int type, clu_offset, max_dentries;
72 struct exfat_chain dir, clu;
73 struct exfat_uni_name uni_name;
74 struct exfat_dentry *ep;
75 struct super_block *sb = inode->i_sb;
76 struct exfat_sb_info *sbi = EXFAT_SB(sb);
77 struct exfat_inode_info *ei = EXFAT_I(inode);
78 unsigned int dentry = EXFAT_B_TO_DEN(*cpos) & 0xFFFFFFFF;
79 struct buffer_head *bh;
80
81 /* check if the given file ID is opened */
82 if (ei->type != TYPE_DIR)
83 return -EPERM;
84
85 exfat_chain_set(&dir, ei->start_clu,
86 EXFAT_B_TO_CLU(i_size_read(inode), sbi), ei->flags);
87
88 dentries_per_clu = sbi->dentries_per_clu;
89 max_dentries = (unsigned int)min_t(u64, MAX_EXFAT_DENTRIES,
90 (u64)EXFAT_CLU_TO_DEN(sbi->num_clusters, sbi));
91
92 clu_offset = EXFAT_DEN_TO_CLU(dentry, sbi);
93 exfat_chain_dup(&clu, &dir);
94
95 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
96 clu.dir += clu_offset;
97 clu.size -= clu_offset;
98 } else {
99 /* hint_information */
100 if (clu_offset > 0 && ei->hint_bmap.off != EXFAT_EOF_CLUSTER &&
101 ei->hint_bmap.off > 0 && clu_offset >= ei->hint_bmap.off) {
102 clu_offset -= ei->hint_bmap.off;
103 clu.dir = ei->hint_bmap.clu;
104 }
105
106 while (clu_offset > 0 && clu.dir != EXFAT_EOF_CLUSTER) {
107 if (exfat_get_next_cluster(sb, &(clu.dir)))
108 return -EIO;
109
110 clu_offset--;
111 }
112 }
113
114 while (clu.dir != EXFAT_EOF_CLUSTER && dentry < max_dentries) {
115 i = dentry & (dentries_per_clu - 1);
116
117 for ( ; i < dentries_per_clu; i++, dentry++) {
118 ep = exfat_get_dentry(sb, &clu, i, &bh);
119 if (!ep)
120 return -EIO;
121
122 type = exfat_get_entry_type(ep);
123 if (type == TYPE_UNUSED) {
124 brelse(bh);
125 break;
126 }
127
128 if (type != TYPE_FILE && type != TYPE_DIR) {
129 brelse(bh);
130 continue;
131 }
132
133 num_ext = ep->dentry.file.num_ext;
134 dir_entry->attr = le16_to_cpu(ep->dentry.file.attr);
135
136 *uni_name.name = 0x0;
137 err = exfat_get_uniname_from_ext_entry(sb, &clu, i,
138 uni_name.name);
139 if (err) {
140 brelse(bh);
141 continue;
142 }
143 exfat_utf16_to_nls(sb, &uni_name,
144 dir_entry->namebuf.lfn,
145 dir_entry->namebuf.lfnbuf_len);
146 brelse(bh);
147
148 ep = exfat_get_dentry(sb, &clu, i + 1, &bh);
149 if (!ep)
150 return -EIO;
151 dir_entry->entry = i;
152 dir_entry->dir = clu;
153 brelse(bh);
154
155 ei->hint_bmap.off = EXFAT_DEN_TO_CLU(dentry, sbi);
156 ei->hint_bmap.clu = clu.dir;
157
158 *cpos = EXFAT_DEN_TO_B(dentry + 1 + num_ext);
159 return 0;
160 }
161
162 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
163 if (--clu.size > 0)
164 clu.dir++;
165 else
166 clu.dir = EXFAT_EOF_CLUSTER;
167 } else {
168 if (exfat_get_next_cluster(sb, &(clu.dir)))
169 return -EIO;
170 }
171 }
172
173 dir_entry->namebuf.lfn[0] = '\0';
174 *cpos = EXFAT_DEN_TO_B(dentry);
175 return 0;
176 }
177
exfat_init_namebuf(struct exfat_dentry_namebuf * nb)178 static void exfat_init_namebuf(struct exfat_dentry_namebuf *nb)
179 {
180 nb->lfn = NULL;
181 nb->lfnbuf_len = 0;
182 }
183
exfat_alloc_namebuf(struct exfat_dentry_namebuf * nb)184 static int exfat_alloc_namebuf(struct exfat_dentry_namebuf *nb)
185 {
186 nb->lfn = __getname();
187 if (!nb->lfn)
188 return -ENOMEM;
189 nb->lfnbuf_len = MAX_VFSNAME_BUF_SIZE;
190 return 0;
191 }
192
exfat_free_namebuf(struct exfat_dentry_namebuf * nb)193 static void exfat_free_namebuf(struct exfat_dentry_namebuf *nb)
194 {
195 if (!nb->lfn)
196 return;
197
198 __putname(nb->lfn);
199 exfat_init_namebuf(nb);
200 }
201
202 /*
203 * Before calling dir_emit*(), sbi->s_lock should be released
204 * because page fault can occur in dir_emit*().
205 */
206 #define ITER_POS_FILLED_DOTS (2)
exfat_iterate(struct file * file,struct dir_context * ctx)207 static int exfat_iterate(struct file *file, struct dir_context *ctx)
208 {
209 struct inode *inode = file_inode(file);
210 struct super_block *sb = inode->i_sb;
211 struct inode *tmp;
212 struct exfat_dir_entry de;
213 struct exfat_dentry_namebuf *nb = &(de.namebuf);
214 struct exfat_inode_info *ei = EXFAT_I(inode);
215 unsigned long inum;
216 loff_t cpos, i_pos;
217 int err = 0, fake_offset = 0;
218
219 exfat_init_namebuf(nb);
220
221 cpos = ctx->pos;
222 if (!dir_emit_dots(file, ctx))
223 goto out;
224
225 if (ctx->pos == ITER_POS_FILLED_DOTS) {
226 cpos = 0;
227 fake_offset = 1;
228 }
229
230 cpos = round_up(cpos, DENTRY_SIZE);
231
232 /* name buffer should be allocated before use */
233 err = exfat_alloc_namebuf(nb);
234 if (err)
235 goto out;
236 get_new:
237 mutex_lock(&EXFAT_SB(sb)->s_lock);
238
239 if (ei->flags == ALLOC_NO_FAT_CHAIN && cpos >= i_size_read(inode))
240 goto end_of_dir;
241
242 err = exfat_readdir(inode, &cpos, &de);
243 if (err) {
244 /*
245 * At least we tried to read a sector.
246 * Move cpos to next sector position (should be aligned).
247 */
248 if (err == -EIO) {
249 cpos += 1 << (sb->s_blocksize_bits);
250 cpos &= ~(sb->s_blocksize - 1);
251 }
252
253 err = -EIO;
254 goto end_of_dir;
255 }
256
257 if (!nb->lfn[0])
258 goto end_of_dir;
259
260 i_pos = ((loff_t)de.dir.dir << 32) | (de.entry & 0xffffffff);
261 tmp = exfat_iget(sb, i_pos);
262 if (tmp) {
263 inum = tmp->i_ino;
264 iput(tmp);
265 } else {
266 inum = iunique(sb, EXFAT_ROOT_INO);
267 }
268
269 mutex_unlock(&EXFAT_SB(sb)->s_lock);
270 if (!dir_emit(ctx, nb->lfn, strlen(nb->lfn), inum,
271 (de.attr & EXFAT_ATTR_SUBDIR) ? DT_DIR : DT_REG))
272 goto out;
273 ctx->pos = cpos;
274 goto get_new;
275
276 end_of_dir:
277 if (!cpos && fake_offset)
278 cpos = ITER_POS_FILLED_DOTS;
279 ctx->pos = cpos;
280 mutex_unlock(&EXFAT_SB(sb)->s_lock);
281 out:
282 /*
283 * To improve performance, free namebuf after unlock sb_lock.
284 * If namebuf is not allocated, this function do nothing
285 */
286 exfat_free_namebuf(nb);
287 return err;
288 }
289
290 WRAP_DIR_ITER(exfat_iterate) // FIXME!
291 const struct file_operations exfat_dir_operations = {
292 .llseek = generic_file_llseek,
293 .read = generic_read_dir,
294 .iterate_shared = shared_exfat_iterate,
295 .unlocked_ioctl = exfat_ioctl,
296 #ifdef CONFIG_COMPAT
297 .compat_ioctl = exfat_compat_ioctl,
298 #endif
299 .fsync = exfat_file_fsync,
300 };
301
exfat_alloc_new_dir(struct inode * inode,struct exfat_chain * clu)302 int exfat_alloc_new_dir(struct inode *inode, struct exfat_chain *clu)
303 {
304 int ret;
305
306 exfat_chain_set(clu, EXFAT_EOF_CLUSTER, 0, ALLOC_NO_FAT_CHAIN);
307
308 ret = exfat_alloc_cluster(inode, 1, clu, IS_DIRSYNC(inode));
309 if (ret)
310 return ret;
311
312 return exfat_zeroed_cluster(inode, clu->dir);
313 }
314
exfat_calc_num_entries(struct exfat_uni_name * p_uniname)315 int exfat_calc_num_entries(struct exfat_uni_name *p_uniname)
316 {
317 int len;
318
319 len = p_uniname->name_len;
320 if (len == 0)
321 return -EINVAL;
322
323 /* 1 file entry + 1 stream entry + name entries */
324 return ES_ENTRY_NUM(len);
325 }
326
exfat_get_entry_type(struct exfat_dentry * ep)327 unsigned int exfat_get_entry_type(struct exfat_dentry *ep)
328 {
329 if (ep->type == EXFAT_UNUSED)
330 return TYPE_UNUSED;
331 if (IS_EXFAT_DELETED(ep->type))
332 return TYPE_DELETED;
333 if (ep->type == EXFAT_INVAL)
334 return TYPE_INVALID;
335 if (IS_EXFAT_CRITICAL_PRI(ep->type)) {
336 if (ep->type == EXFAT_BITMAP)
337 return TYPE_BITMAP;
338 if (ep->type == EXFAT_UPCASE)
339 return TYPE_UPCASE;
340 if (ep->type == EXFAT_VOLUME)
341 return TYPE_VOLUME;
342 if (ep->type == EXFAT_FILE) {
343 if (le16_to_cpu(ep->dentry.file.attr) & EXFAT_ATTR_SUBDIR)
344 return TYPE_DIR;
345 return TYPE_FILE;
346 }
347 return TYPE_CRITICAL_PRI;
348 }
349 if (IS_EXFAT_BENIGN_PRI(ep->type)) {
350 if (ep->type == EXFAT_GUID)
351 return TYPE_GUID;
352 if (ep->type == EXFAT_PADDING)
353 return TYPE_PADDING;
354 if (ep->type == EXFAT_ACLTAB)
355 return TYPE_ACLTAB;
356 return TYPE_BENIGN_PRI;
357 }
358 if (IS_EXFAT_CRITICAL_SEC(ep->type)) {
359 if (ep->type == EXFAT_STREAM)
360 return TYPE_STREAM;
361 if (ep->type == EXFAT_NAME)
362 return TYPE_EXTEND;
363 if (ep->type == EXFAT_ACL)
364 return TYPE_ACL;
365 return TYPE_CRITICAL_SEC;
366 }
367
368 if (ep->type == EXFAT_VENDOR_EXT)
369 return TYPE_VENDOR_EXT;
370 if (ep->type == EXFAT_VENDOR_ALLOC)
371 return TYPE_VENDOR_ALLOC;
372
373 return TYPE_BENIGN_SEC;
374 }
375
exfat_set_entry_type(struct exfat_dentry * ep,unsigned int type)376 static void exfat_set_entry_type(struct exfat_dentry *ep, unsigned int type)
377 {
378 if (type == TYPE_UNUSED) {
379 ep->type = EXFAT_UNUSED;
380 } else if (type == TYPE_DELETED) {
381 ep->type &= EXFAT_DELETE;
382 } else if (type == TYPE_STREAM) {
383 ep->type = EXFAT_STREAM;
384 } else if (type == TYPE_EXTEND) {
385 ep->type = EXFAT_NAME;
386 } else if (type == TYPE_BITMAP) {
387 ep->type = EXFAT_BITMAP;
388 } else if (type == TYPE_UPCASE) {
389 ep->type = EXFAT_UPCASE;
390 } else if (type == TYPE_VOLUME) {
391 ep->type = EXFAT_VOLUME;
392 } else if (type == TYPE_DIR) {
393 ep->type = EXFAT_FILE;
394 ep->dentry.file.attr = cpu_to_le16(EXFAT_ATTR_SUBDIR);
395 } else if (type == TYPE_FILE) {
396 ep->type = EXFAT_FILE;
397 ep->dentry.file.attr = cpu_to_le16(EXFAT_ATTR_ARCHIVE);
398 }
399 }
400
exfat_init_stream_entry(struct exfat_dentry * ep,unsigned int start_clu,unsigned long long size)401 static void exfat_init_stream_entry(struct exfat_dentry *ep,
402 unsigned int start_clu, unsigned long long size)
403 {
404 memset(ep, 0, sizeof(*ep));
405 exfat_set_entry_type(ep, TYPE_STREAM);
406 if (size == 0)
407 ep->dentry.stream.flags = ALLOC_FAT_CHAIN;
408 else
409 ep->dentry.stream.flags = ALLOC_NO_FAT_CHAIN;
410 ep->dentry.stream.start_clu = cpu_to_le32(start_clu);
411 ep->dentry.stream.valid_size = cpu_to_le64(size);
412 ep->dentry.stream.size = cpu_to_le64(size);
413 }
414
exfat_init_name_entry(struct exfat_dentry * ep,unsigned short * uniname)415 static void exfat_init_name_entry(struct exfat_dentry *ep,
416 unsigned short *uniname)
417 {
418 int i;
419
420 exfat_set_entry_type(ep, TYPE_EXTEND);
421 ep->dentry.name.flags = 0x0;
422
423 for (i = 0; i < EXFAT_FILE_NAME_LEN; i++) {
424 if (*uniname != 0x0) {
425 ep->dentry.name.unicode_0_14[i] = cpu_to_le16(*uniname);
426 uniname++;
427 } else {
428 ep->dentry.name.unicode_0_14[i] = 0x0;
429 }
430 }
431 }
432
exfat_init_dir_entry(struct exfat_entry_set_cache * es,unsigned int type,unsigned int start_clu,unsigned long long size,struct timespec64 * ts)433 void exfat_init_dir_entry(struct exfat_entry_set_cache *es,
434 unsigned int type, unsigned int start_clu,
435 unsigned long long size, struct timespec64 *ts)
436 {
437 struct super_block *sb = es->sb;
438 struct exfat_sb_info *sbi = EXFAT_SB(sb);
439 struct exfat_dentry *ep;
440
441 ep = exfat_get_dentry_cached(es, ES_IDX_FILE);
442 memset(ep, 0, sizeof(*ep));
443 exfat_set_entry_type(ep, type);
444 exfat_set_entry_time(sbi, ts,
445 &ep->dentry.file.create_tz,
446 &ep->dentry.file.create_time,
447 &ep->dentry.file.create_date,
448 &ep->dentry.file.create_time_cs);
449 exfat_set_entry_time(sbi, ts,
450 &ep->dentry.file.modify_tz,
451 &ep->dentry.file.modify_time,
452 &ep->dentry.file.modify_date,
453 &ep->dentry.file.modify_time_cs);
454 exfat_set_entry_time(sbi, ts,
455 &ep->dentry.file.access_tz,
456 &ep->dentry.file.access_time,
457 &ep->dentry.file.access_date,
458 NULL);
459
460 ep = exfat_get_dentry_cached(es, ES_IDX_STREAM);
461 exfat_init_stream_entry(ep, start_clu, size);
462 }
463
exfat_free_benign_secondary_clusters(struct inode * inode,struct exfat_dentry * ep)464 static void exfat_free_benign_secondary_clusters(struct inode *inode,
465 struct exfat_dentry *ep)
466 {
467 struct super_block *sb = inode->i_sb;
468 struct exfat_chain dir;
469 unsigned int start_clu =
470 le32_to_cpu(ep->dentry.generic_secondary.start_clu);
471 u64 size = le64_to_cpu(ep->dentry.generic_secondary.size);
472 unsigned char flags = ep->dentry.generic_secondary.flags;
473
474 if (!(flags & ALLOC_POSSIBLE) || !start_clu || !size)
475 return;
476
477 exfat_chain_set(&dir, start_clu,
478 EXFAT_B_TO_CLU_ROUND_UP(size, EXFAT_SB(sb)),
479 flags);
480 exfat_free_cluster(inode, &dir);
481 }
482
exfat_init_ext_entry(struct exfat_entry_set_cache * es,int num_entries,struct exfat_uni_name * p_uniname)483 void exfat_init_ext_entry(struct exfat_entry_set_cache *es, int num_entries,
484 struct exfat_uni_name *p_uniname)
485 {
486 int i;
487 unsigned short *uniname = p_uniname->name;
488 struct exfat_dentry *ep;
489
490 ep = exfat_get_dentry_cached(es, ES_IDX_FILE);
491 ep->dentry.file.num_ext = (unsigned char)(num_entries - 1);
492
493 ep = exfat_get_dentry_cached(es, ES_IDX_STREAM);
494 ep->dentry.stream.name_len = p_uniname->name_len;
495 ep->dentry.stream.name_hash = cpu_to_le16(p_uniname->name_hash);
496
497 for (i = ES_IDX_FIRST_FILENAME; i < num_entries; i++) {
498 ep = exfat_get_dentry_cached(es, i);
499 exfat_init_name_entry(ep, uniname);
500 uniname += EXFAT_FILE_NAME_LEN;
501 }
502
503 exfat_update_dir_chksum(es);
504 }
505
exfat_remove_entries(struct inode * inode,struct exfat_entry_set_cache * es,int order)506 void exfat_remove_entries(struct inode *inode, struct exfat_entry_set_cache *es,
507 int order)
508 {
509 int i;
510 struct exfat_dentry *ep;
511
512 for (i = order; i < es->num_entries; i++) {
513 ep = exfat_get_dentry_cached(es, i);
514
515 if (exfat_get_entry_type(ep) & TYPE_BENIGN_SEC)
516 exfat_free_benign_secondary_clusters(inode, ep);
517
518 exfat_set_entry_type(ep, TYPE_DELETED);
519 }
520
521 if (order < es->num_entries)
522 es->modified = true;
523 }
524
exfat_update_dir_chksum(struct exfat_entry_set_cache * es)525 void exfat_update_dir_chksum(struct exfat_entry_set_cache *es)
526 {
527 int chksum_type = CS_DIR_ENTRY, i;
528 unsigned short chksum = 0;
529 struct exfat_dentry *ep;
530
531 for (i = ES_IDX_FILE; i < es->num_entries; i++) {
532 ep = exfat_get_dentry_cached(es, i);
533 chksum = exfat_calc_chksum16(ep, DENTRY_SIZE, chksum,
534 chksum_type);
535 chksum_type = CS_DEFAULT;
536 }
537 ep = exfat_get_dentry_cached(es, ES_IDX_FILE);
538 ep->dentry.file.checksum = cpu_to_le16(chksum);
539 es->modified = true;
540 }
541
exfat_put_dentry_set(struct exfat_entry_set_cache * es,int sync)542 int exfat_put_dentry_set(struct exfat_entry_set_cache *es, int sync)
543 {
544 int i, err = 0;
545
546 if (es->modified)
547 err = exfat_update_bhs(es->bh, es->num_bh, sync);
548
549 for (i = 0; i < es->num_bh; i++)
550 if (err)
551 bforget(es->bh[i]);
552 else
553 brelse(es->bh[i]);
554
555 if (IS_DYNAMIC_ES(es))
556 kfree(es->bh);
557
558 return err;
559 }
560
exfat_walk_fat_chain(struct super_block * sb,struct exfat_chain * p_dir,unsigned int byte_offset,unsigned int * clu)561 static int exfat_walk_fat_chain(struct super_block *sb,
562 struct exfat_chain *p_dir, unsigned int byte_offset,
563 unsigned int *clu)
564 {
565 struct exfat_sb_info *sbi = EXFAT_SB(sb);
566 unsigned int clu_offset;
567 unsigned int cur_clu;
568
569 clu_offset = EXFAT_B_TO_CLU(byte_offset, sbi);
570 cur_clu = p_dir->dir;
571
572 if (p_dir->flags == ALLOC_NO_FAT_CHAIN) {
573 cur_clu += clu_offset;
574 } else {
575 while (clu_offset > 0) {
576 if (exfat_get_next_cluster(sb, &cur_clu))
577 return -EIO;
578 if (cur_clu == EXFAT_EOF_CLUSTER) {
579 exfat_fs_error(sb,
580 "invalid dentry access beyond EOF (clu : %u, eidx : %d)",
581 p_dir->dir,
582 EXFAT_B_TO_DEN(byte_offset));
583 return -EIO;
584 }
585 clu_offset--;
586 }
587 }
588
589 *clu = cur_clu;
590 return 0;
591 }
592
exfat_find_location(struct super_block * sb,struct exfat_chain * p_dir,int entry,sector_t * sector,int * offset)593 static int exfat_find_location(struct super_block *sb, struct exfat_chain *p_dir,
594 int entry, sector_t *sector, int *offset)
595 {
596 int ret;
597 unsigned int off, clu = 0;
598 struct exfat_sb_info *sbi = EXFAT_SB(sb);
599
600 off = EXFAT_DEN_TO_B(entry);
601
602 ret = exfat_walk_fat_chain(sb, p_dir, off, &clu);
603 if (ret)
604 return ret;
605
606 /* byte offset in cluster */
607 off = EXFAT_CLU_OFFSET(off, sbi);
608
609 /* byte offset in sector */
610 *offset = EXFAT_BLK_OFFSET(off, sb);
611
612 /* sector offset in cluster */
613 *sector = EXFAT_B_TO_BLK(off, sb);
614 *sector += exfat_cluster_to_sector(sbi, clu);
615 return 0;
616 }
617
618 #define EXFAT_MAX_RA_SIZE (128*1024)
exfat_dir_readahead(struct super_block * sb,sector_t sec)619 static int exfat_dir_readahead(struct super_block *sb, sector_t sec)
620 {
621 struct exfat_sb_info *sbi = EXFAT_SB(sb);
622 struct buffer_head *bh;
623 unsigned int max_ra_count = EXFAT_MAX_RA_SIZE >> sb->s_blocksize_bits;
624 unsigned int page_ra_count = PAGE_SIZE >> sb->s_blocksize_bits;
625 unsigned int adj_ra_count = max(sbi->sect_per_clus, page_ra_count);
626 unsigned int ra_count = min(adj_ra_count, max_ra_count);
627
628 /* Read-ahead is not required */
629 if (sbi->sect_per_clus == 1)
630 return 0;
631
632 if (sec < sbi->data_start_sector) {
633 exfat_err(sb, "requested sector is invalid(sect:%llu, root:%llu)",
634 (unsigned long long)sec, sbi->data_start_sector);
635 return -EIO;
636 }
637
638 /* Not sector aligned with ra_count, resize ra_count to page size */
639 if ((sec - sbi->data_start_sector) & (ra_count - 1))
640 ra_count = page_ra_count;
641
642 bh = sb_find_get_block(sb, sec);
643 if (!bh || !buffer_uptodate(bh)) {
644 unsigned int i;
645
646 for (i = 0; i < ra_count; i++)
647 sb_breadahead(sb, (sector_t)(sec + i));
648 }
649 brelse(bh);
650 return 0;
651 }
652
exfat_get_dentry(struct super_block * sb,struct exfat_chain * p_dir,int entry,struct buffer_head ** bh)653 struct exfat_dentry *exfat_get_dentry(struct super_block *sb,
654 struct exfat_chain *p_dir, int entry, struct buffer_head **bh)
655 {
656 unsigned int dentries_per_page = EXFAT_B_TO_DEN(PAGE_SIZE);
657 int off;
658 sector_t sec;
659
660 if (p_dir->dir == DIR_DELETED) {
661 exfat_err(sb, "abnormal access to deleted dentry");
662 return NULL;
663 }
664
665 if (exfat_find_location(sb, p_dir, entry, &sec, &off))
666 return NULL;
667
668 if (p_dir->dir != EXFAT_FREE_CLUSTER &&
669 !(entry & (dentries_per_page - 1)))
670 exfat_dir_readahead(sb, sec);
671
672 *bh = sb_bread(sb, sec);
673 if (!*bh)
674 return NULL;
675
676 return (struct exfat_dentry *)((*bh)->b_data + off);
677 }
678
679 enum exfat_validate_dentry_mode {
680 ES_MODE_GET_FILE_ENTRY,
681 ES_MODE_GET_STRM_ENTRY,
682 ES_MODE_GET_NAME_ENTRY,
683 ES_MODE_GET_CRITICAL_SEC_ENTRY,
684 ES_MODE_GET_BENIGN_SEC_ENTRY,
685 };
686
exfat_validate_entry(unsigned int type,enum exfat_validate_dentry_mode * mode)687 static bool exfat_validate_entry(unsigned int type,
688 enum exfat_validate_dentry_mode *mode)
689 {
690 if (type == TYPE_UNUSED || type == TYPE_DELETED)
691 return false;
692
693 switch (*mode) {
694 case ES_MODE_GET_FILE_ENTRY:
695 if (type != TYPE_STREAM)
696 return false;
697 *mode = ES_MODE_GET_STRM_ENTRY;
698 break;
699 case ES_MODE_GET_STRM_ENTRY:
700 if (type != TYPE_EXTEND)
701 return false;
702 *mode = ES_MODE_GET_NAME_ENTRY;
703 break;
704 case ES_MODE_GET_NAME_ENTRY:
705 if (type & TYPE_BENIGN_SEC)
706 *mode = ES_MODE_GET_BENIGN_SEC_ENTRY;
707 else if (type != TYPE_EXTEND)
708 return false;
709 break;
710 case ES_MODE_GET_BENIGN_SEC_ENTRY:
711 /* Assume unreconized benign secondary entry */
712 if (!(type & TYPE_BENIGN_SEC))
713 return false;
714 break;
715 default:
716 return false;
717 }
718
719 return true;
720 }
721
exfat_get_dentry_cached(struct exfat_entry_set_cache * es,int num)722 struct exfat_dentry *exfat_get_dentry_cached(
723 struct exfat_entry_set_cache *es, int num)
724 {
725 int off = es->start_off + num * DENTRY_SIZE;
726 struct buffer_head *bh = es->bh[EXFAT_B_TO_BLK(off, es->sb)];
727 char *p = bh->b_data + EXFAT_BLK_OFFSET(off, es->sb);
728
729 return (struct exfat_dentry *)p;
730 }
731
732 /*
733 * Returns a set of dentries.
734 *
735 * Note It provides a direct pointer to bh->data via exfat_get_dentry_cached().
736 * User should call exfat_get_dentry_set() after setting 'modified' to apply
737 * changes made in this entry set to the real device.
738 *
739 * in:
740 * sb+p_dir+entry: indicates a file/dir
741 * num_entries: specifies how many dentries should be included.
742 * It will be set to es->num_entries if it is not 0.
743 * If num_entries is 0, es->num_entries will be obtained
744 * from the first dentry.
745 * out:
746 * es: pointer of entry set on success.
747 * return:
748 * 0 on success
749 * -error code on failure
750 */
__exfat_get_dentry_set(struct exfat_entry_set_cache * es,struct super_block * sb,struct exfat_chain * p_dir,int entry,unsigned int num_entries)751 static int __exfat_get_dentry_set(struct exfat_entry_set_cache *es,
752 struct super_block *sb, struct exfat_chain *p_dir, int entry,
753 unsigned int num_entries)
754 {
755 int ret, i, num_bh;
756 unsigned int off;
757 sector_t sec;
758 struct exfat_sb_info *sbi = EXFAT_SB(sb);
759 struct buffer_head *bh;
760
761 if (p_dir->dir == DIR_DELETED) {
762 exfat_err(sb, "access to deleted dentry");
763 return -EIO;
764 }
765
766 ret = exfat_find_location(sb, p_dir, entry, &sec, &off);
767 if (ret)
768 return ret;
769
770 memset(es, 0, sizeof(*es));
771 es->sb = sb;
772 es->modified = false;
773 es->start_off = off;
774 es->bh = es->__bh;
775
776 bh = sb_bread(sb, sec);
777 if (!bh)
778 return -EIO;
779 es->bh[es->num_bh++] = bh;
780
781 if (num_entries == ES_ALL_ENTRIES) {
782 struct exfat_dentry *ep;
783
784 ep = exfat_get_dentry_cached(es, ES_IDX_FILE);
785 if (ep->type != EXFAT_FILE) {
786 brelse(bh);
787 return -EIO;
788 }
789
790 num_entries = ep->dentry.file.num_ext + 1;
791 }
792
793 es->num_entries = num_entries;
794
795 num_bh = EXFAT_B_TO_BLK_ROUND_UP(off + num_entries * DENTRY_SIZE, sb);
796 if (num_bh > ARRAY_SIZE(es->__bh)) {
797 es->bh = kmalloc_array(num_bh, sizeof(*es->bh), GFP_NOFS);
798 if (!es->bh) {
799 brelse(bh);
800 return -ENOMEM;
801 }
802 es->bh[0] = bh;
803 }
804
805 for (i = 1; i < num_bh; i++) {
806 /* get the next sector */
807 if (exfat_is_last_sector_in_cluster(sbi, sec)) {
808 unsigned int clu = exfat_sector_to_cluster(sbi, sec);
809
810 if (p_dir->flags == ALLOC_NO_FAT_CHAIN)
811 clu++;
812 else if (exfat_get_next_cluster(sb, &clu))
813 goto put_es;
814 sec = exfat_cluster_to_sector(sbi, clu);
815 } else {
816 sec++;
817 }
818
819 bh = sb_bread(sb, sec);
820 if (!bh)
821 goto put_es;
822 es->bh[es->num_bh++] = bh;
823 }
824
825 return 0;
826
827 put_es:
828 exfat_put_dentry_set(es, false);
829 return -EIO;
830 }
831
exfat_get_dentry_set(struct exfat_entry_set_cache * es,struct super_block * sb,struct exfat_chain * p_dir,int entry,unsigned int num_entries)832 int exfat_get_dentry_set(struct exfat_entry_set_cache *es,
833 struct super_block *sb, struct exfat_chain *p_dir,
834 int entry, unsigned int num_entries)
835 {
836 int ret, i;
837 struct exfat_dentry *ep;
838 enum exfat_validate_dentry_mode mode = ES_MODE_GET_FILE_ENTRY;
839
840 ret = __exfat_get_dentry_set(es, sb, p_dir, entry, num_entries);
841 if (ret < 0)
842 return ret;
843
844 /* validate cached dentries */
845 for (i = ES_IDX_STREAM; i < es->num_entries; i++) {
846 ep = exfat_get_dentry_cached(es, i);
847 if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
848 goto put_es;
849 }
850 return 0;
851
852 put_es:
853 exfat_put_dentry_set(es, false);
854 return -EIO;
855 }
856
exfat_validate_empty_dentry_set(struct exfat_entry_set_cache * es)857 static int exfat_validate_empty_dentry_set(struct exfat_entry_set_cache *es)
858 {
859 struct exfat_dentry *ep;
860 struct buffer_head *bh;
861 int i, off;
862 bool unused_hit = false;
863
864 /*
865 * ONLY UNUSED OR DELETED DENTRIES ARE ALLOWED:
866 * Although it violates the specification for a deleted entry to
867 * follow an unused entry, some exFAT implementations could work
868 * like this. Therefore, to improve compatibility, let's allow it.
869 */
870 for (i = 0; i < es->num_entries; i++) {
871 ep = exfat_get_dentry_cached(es, i);
872 if (ep->type == EXFAT_UNUSED) {
873 unused_hit = true;
874 } else if (!IS_EXFAT_DELETED(ep->type)) {
875 if (unused_hit)
876 goto err_used_follow_unused;
877 i++;
878 goto count_skip_entries;
879 }
880 }
881
882 return 0;
883
884 err_used_follow_unused:
885 off = es->start_off + (i << DENTRY_SIZE_BITS);
886 bh = es->bh[EXFAT_B_TO_BLK(off, es->sb)];
887
888 exfat_fs_error(es->sb,
889 "in sector %lld, dentry %d should be unused, but 0x%x",
890 bh->b_blocknr, off >> DENTRY_SIZE_BITS, ep->type);
891
892 return -EIO;
893
894 count_skip_entries:
895 es->num_entries = EXFAT_B_TO_DEN(EXFAT_BLK_TO_B(es->num_bh, es->sb) - es->start_off);
896 for (; i < es->num_entries; i++) {
897 ep = exfat_get_dentry_cached(es, i);
898 if (IS_EXFAT_DELETED(ep->type))
899 break;
900 }
901
902 return i;
903 }
904
905 /*
906 * Get an empty dentry set.
907 *
908 * in:
909 * sb+p_dir+entry: indicates the empty dentry location
910 * num_entries: specifies how many empty dentries should be included.
911 * out:
912 * es: pointer of empty dentry set on success.
913 * return:
914 * 0 : on success
915 * >0 : the dentries are not empty, the return value is the number of
916 * dentries to be skipped for the next lookup.
917 * <0 : on failure
918 */
exfat_get_empty_dentry_set(struct exfat_entry_set_cache * es,struct super_block * sb,struct exfat_chain * p_dir,int entry,unsigned int num_entries)919 int exfat_get_empty_dentry_set(struct exfat_entry_set_cache *es,
920 struct super_block *sb, struct exfat_chain *p_dir,
921 int entry, unsigned int num_entries)
922 {
923 int ret;
924
925 ret = __exfat_get_dentry_set(es, sb, p_dir, entry, num_entries);
926 if (ret < 0)
927 return ret;
928
929 ret = exfat_validate_empty_dentry_set(es);
930 if (ret)
931 exfat_put_dentry_set(es, false);
932
933 return ret;
934 }
935
exfat_reset_empty_hint(struct exfat_hint_femp * hint_femp)936 static inline void exfat_reset_empty_hint(struct exfat_hint_femp *hint_femp)
937 {
938 hint_femp->eidx = EXFAT_HINT_NONE;
939 hint_femp->count = 0;
940 }
941
exfat_set_empty_hint(struct exfat_inode_info * ei,struct exfat_hint_femp * candi_empty,struct exfat_chain * clu,int dentry,int num_entries,int entry_type)942 static inline void exfat_set_empty_hint(struct exfat_inode_info *ei,
943 struct exfat_hint_femp *candi_empty, struct exfat_chain *clu,
944 int dentry, int num_entries, int entry_type)
945 {
946 if (ei->hint_femp.eidx == EXFAT_HINT_NONE ||
947 ei->hint_femp.eidx > dentry) {
948 int total_entries = EXFAT_B_TO_DEN(i_size_read(&ei->vfs_inode));
949
950 if (candi_empty->count == 0) {
951 candi_empty->cur = *clu;
952 candi_empty->eidx = dentry;
953 }
954
955 if (entry_type == TYPE_UNUSED)
956 candi_empty->count += total_entries - dentry;
957 else
958 candi_empty->count++;
959
960 if (candi_empty->count == num_entries ||
961 candi_empty->count + candi_empty->eidx == total_entries)
962 ei->hint_femp = *candi_empty;
963 }
964 }
965
966 enum {
967 DIRENT_STEP_FILE,
968 DIRENT_STEP_STRM,
969 DIRENT_STEP_NAME,
970 DIRENT_STEP_SECD,
971 };
972
973 /*
974 * @ei: inode info of parent directory
975 * @p_dir: directory structure of parent directory
976 * @num_entries:entry size of p_uniname
977 * @hint_opt: If p_uniname is found, filled with optimized dir/entry
978 * for traversing cluster chain.
979 * @return:
980 * >= 0: file directory entry position where the name exists
981 * -ENOENT: entry with the name does not exist
982 * -EIO: I/O error
983 */
exfat_find_dir_entry(struct super_block * sb,struct exfat_inode_info * ei,struct exfat_chain * p_dir,struct exfat_uni_name * p_uniname,struct exfat_hint * hint_opt)984 int exfat_find_dir_entry(struct super_block *sb, struct exfat_inode_info *ei,
985 struct exfat_chain *p_dir, struct exfat_uni_name *p_uniname,
986 struct exfat_hint *hint_opt)
987 {
988 int i, rewind = 0, dentry = 0, end_eidx = 0, num_ext = 0, len;
989 int order, step, name_len = 0;
990 int dentries_per_clu;
991 unsigned int entry_type;
992 unsigned short *uniname = NULL;
993 struct exfat_chain clu;
994 struct exfat_hint *hint_stat = &ei->hint_stat;
995 struct exfat_hint_femp candi_empty;
996 struct exfat_sb_info *sbi = EXFAT_SB(sb);
997 int num_entries = exfat_calc_num_entries(p_uniname);
998
999 if (num_entries < 0)
1000 return num_entries;
1001
1002 dentries_per_clu = sbi->dentries_per_clu;
1003
1004 exfat_chain_dup(&clu, p_dir);
1005
1006 if (hint_stat->eidx) {
1007 clu.dir = hint_stat->clu;
1008 dentry = hint_stat->eidx;
1009 end_eidx = dentry;
1010 }
1011
1012 exfat_reset_empty_hint(&ei->hint_femp);
1013
1014 rewind:
1015 order = 0;
1016 step = DIRENT_STEP_FILE;
1017 exfat_reset_empty_hint(&candi_empty);
1018
1019 while (clu.dir != EXFAT_EOF_CLUSTER) {
1020 i = dentry & (dentries_per_clu - 1);
1021 for (; i < dentries_per_clu; i++, dentry++) {
1022 struct exfat_dentry *ep;
1023 struct buffer_head *bh;
1024
1025 if (rewind && dentry == end_eidx)
1026 goto not_found;
1027
1028 ep = exfat_get_dentry(sb, &clu, i, &bh);
1029 if (!ep)
1030 return -EIO;
1031
1032 entry_type = exfat_get_entry_type(ep);
1033
1034 if (entry_type == TYPE_UNUSED ||
1035 entry_type == TYPE_DELETED) {
1036 step = DIRENT_STEP_FILE;
1037
1038 exfat_set_empty_hint(ei, &candi_empty, &clu,
1039 dentry, num_entries,
1040 entry_type);
1041
1042 brelse(bh);
1043 if (entry_type == TYPE_UNUSED)
1044 goto not_found;
1045 continue;
1046 }
1047
1048 exfat_reset_empty_hint(&candi_empty);
1049
1050 if (entry_type == TYPE_FILE || entry_type == TYPE_DIR) {
1051 step = DIRENT_STEP_FILE;
1052 hint_opt->clu = clu.dir;
1053 hint_opt->eidx = i;
1054 num_ext = ep->dentry.file.num_ext;
1055 step = DIRENT_STEP_STRM;
1056 brelse(bh);
1057 continue;
1058 }
1059
1060 if (entry_type == TYPE_STREAM) {
1061 u16 name_hash;
1062
1063 if (step != DIRENT_STEP_STRM) {
1064 step = DIRENT_STEP_FILE;
1065 brelse(bh);
1066 continue;
1067 }
1068 step = DIRENT_STEP_FILE;
1069 name_hash = le16_to_cpu(
1070 ep->dentry.stream.name_hash);
1071 if (p_uniname->name_hash == name_hash &&
1072 p_uniname->name_len ==
1073 ep->dentry.stream.name_len) {
1074 step = DIRENT_STEP_NAME;
1075 order = 1;
1076 name_len = 0;
1077 }
1078 brelse(bh);
1079 continue;
1080 }
1081
1082 brelse(bh);
1083 if (entry_type == TYPE_EXTEND) {
1084 unsigned short entry_uniname[16], unichar;
1085
1086 if (step != DIRENT_STEP_NAME ||
1087 name_len >= MAX_NAME_LENGTH) {
1088 step = DIRENT_STEP_FILE;
1089 continue;
1090 }
1091
1092 if (++order == 2)
1093 uniname = p_uniname->name;
1094 else
1095 uniname += EXFAT_FILE_NAME_LEN;
1096
1097 len = exfat_extract_uni_name(ep, entry_uniname);
1098 name_len += len;
1099
1100 unichar = *(uniname+len);
1101 *(uniname+len) = 0x0;
1102
1103 if (exfat_uniname_ncmp(sb, uniname,
1104 entry_uniname, len)) {
1105 step = DIRENT_STEP_FILE;
1106 } else if (p_uniname->name_len == name_len) {
1107 if (order == num_ext)
1108 goto found;
1109 step = DIRENT_STEP_SECD;
1110 }
1111
1112 *(uniname+len) = unichar;
1113 continue;
1114 }
1115
1116 if (entry_type &
1117 (TYPE_CRITICAL_SEC | TYPE_BENIGN_SEC)) {
1118 if (step == DIRENT_STEP_SECD) {
1119 if (++order == num_ext)
1120 goto found;
1121 continue;
1122 }
1123 }
1124 step = DIRENT_STEP_FILE;
1125 }
1126
1127 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1128 if (--clu.size > 0)
1129 clu.dir++;
1130 else
1131 clu.dir = EXFAT_EOF_CLUSTER;
1132 } else {
1133 if (exfat_get_next_cluster(sb, &clu.dir))
1134 return -EIO;
1135 }
1136 }
1137
1138 not_found:
1139 /*
1140 * We started at not 0 index,so we should try to find target
1141 * from 0 index to the index we started at.
1142 */
1143 if (!rewind && end_eidx) {
1144 rewind = 1;
1145 dentry = 0;
1146 clu.dir = p_dir->dir;
1147 goto rewind;
1148 }
1149
1150 /*
1151 * set the EXFAT_EOF_CLUSTER flag to avoid search
1152 * from the beginning again when allocated a new cluster
1153 */
1154 if (ei->hint_femp.eidx == EXFAT_HINT_NONE) {
1155 ei->hint_femp.cur.dir = EXFAT_EOF_CLUSTER;
1156 ei->hint_femp.eidx = p_dir->size * dentries_per_clu;
1157 ei->hint_femp.count = 0;
1158 }
1159
1160 /* initialized hint_stat */
1161 hint_stat->clu = p_dir->dir;
1162 hint_stat->eidx = 0;
1163 return -ENOENT;
1164
1165 found:
1166 /* next dentry we'll find is out of this cluster */
1167 if (!((dentry + 1) & (dentries_per_clu - 1))) {
1168 int ret = 0;
1169
1170 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1171 if (--clu.size > 0)
1172 clu.dir++;
1173 else
1174 clu.dir = EXFAT_EOF_CLUSTER;
1175 } else {
1176 ret = exfat_get_next_cluster(sb, &clu.dir);
1177 }
1178
1179 if (ret || clu.dir == EXFAT_EOF_CLUSTER) {
1180 /* just initialized hint_stat */
1181 hint_stat->clu = p_dir->dir;
1182 hint_stat->eidx = 0;
1183 return (dentry - num_ext);
1184 }
1185 }
1186
1187 hint_stat->clu = clu.dir;
1188 hint_stat->eidx = dentry + 1;
1189 return dentry - num_ext;
1190 }
1191
exfat_count_dir_entries(struct super_block * sb,struct exfat_chain * p_dir)1192 int exfat_count_dir_entries(struct super_block *sb, struct exfat_chain *p_dir)
1193 {
1194 int i, count = 0;
1195 int dentries_per_clu;
1196 unsigned int entry_type;
1197 struct exfat_chain clu;
1198 struct exfat_dentry *ep;
1199 struct exfat_sb_info *sbi = EXFAT_SB(sb);
1200 struct buffer_head *bh;
1201
1202 dentries_per_clu = sbi->dentries_per_clu;
1203
1204 exfat_chain_dup(&clu, p_dir);
1205
1206 while (clu.dir != EXFAT_EOF_CLUSTER) {
1207 for (i = 0; i < dentries_per_clu; i++) {
1208 ep = exfat_get_dentry(sb, &clu, i, &bh);
1209 if (!ep)
1210 return -EIO;
1211 entry_type = exfat_get_entry_type(ep);
1212 brelse(bh);
1213
1214 if (entry_type == TYPE_UNUSED)
1215 return count;
1216 if (entry_type != TYPE_DIR)
1217 continue;
1218 count++;
1219 }
1220
1221 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1222 if (--clu.size > 0)
1223 clu.dir++;
1224 else
1225 clu.dir = EXFAT_EOF_CLUSTER;
1226 } else {
1227 if (exfat_get_next_cluster(sb, &(clu.dir)))
1228 return -EIO;
1229 }
1230 }
1231
1232 return count;
1233 }
1234