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
14static 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
32static 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: &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: &es, num: i);
51
52 /* end of name entry */
53 if (exfat_get_entry_type(p_entry: 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: &es, sync: false);
64 return 0;
65}
66
67/* read a directory entry from the opened directory */
68static 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 if (ei->entry == -1)
86 exfat_chain_set(ec: &dir, dir: sbi->root_dir, size: 0, ALLOC_FAT_CHAIN);
87 else
88 exfat_chain_set(ec: &dir, dir: ei->start_clu,
89 EXFAT_B_TO_CLU(i_size_read(inode), sbi), flags: ei->flags);
90
91 dentries_per_clu = sbi->dentries_per_clu;
92 max_dentries = (unsigned int)min_t(u64, MAX_EXFAT_DENTRIES,
93 (u64)EXFAT_CLU_TO_DEN(sbi->num_clusters, sbi));
94
95 clu_offset = EXFAT_DEN_TO_CLU(dentry, sbi);
96 exfat_chain_dup(dup: &clu, ec: &dir);
97
98 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
99 clu.dir += clu_offset;
100 clu.size -= clu_offset;
101 } else {
102 /* hint_information */
103 if (clu_offset > 0 && ei->hint_bmap.off != EXFAT_EOF_CLUSTER &&
104 ei->hint_bmap.off > 0 && clu_offset >= ei->hint_bmap.off) {
105 clu_offset -= ei->hint_bmap.off;
106 clu.dir = ei->hint_bmap.clu;
107 }
108
109 while (clu_offset > 0 && clu.dir != EXFAT_EOF_CLUSTER) {
110 if (exfat_get_next_cluster(sb, &(clu.dir)))
111 return -EIO;
112
113 clu_offset--;
114 }
115 }
116
117 while (clu.dir != EXFAT_EOF_CLUSTER && dentry < max_dentries) {
118 i = dentry & (dentries_per_clu - 1);
119
120 for ( ; i < dentries_per_clu; i++, dentry++) {
121 ep = exfat_get_dentry(sb, p_dir: &clu, entry: i, bh: &bh);
122 if (!ep)
123 return -EIO;
124
125 type = exfat_get_entry_type(p_entry: ep);
126 if (type == TYPE_UNUSED) {
127 brelse(bh);
128 break;
129 }
130
131 if (type != TYPE_FILE && type != TYPE_DIR) {
132 brelse(bh);
133 continue;
134 }
135
136 num_ext = ep->dentry.file.num_ext;
137 dir_entry->attr = le16_to_cpu(ep->dentry.file.attr);
138 exfat_get_entry_time(sbi, ts: &dir_entry->crtime,
139 tz: ep->dentry.file.create_tz,
140 time: ep->dentry.file.create_time,
141 date: ep->dentry.file.create_date,
142 time_cs: ep->dentry.file.create_time_cs);
143 exfat_get_entry_time(sbi, ts: &dir_entry->mtime,
144 tz: ep->dentry.file.modify_tz,
145 time: ep->dentry.file.modify_time,
146 date: ep->dentry.file.modify_date,
147 time_cs: ep->dentry.file.modify_time_cs);
148 exfat_get_entry_time(sbi, ts: &dir_entry->atime,
149 tz: ep->dentry.file.access_tz,
150 time: ep->dentry.file.access_time,
151 date: ep->dentry.file.access_date,
152 time_cs: 0);
153
154 *uni_name.name = 0x0;
155 err = exfat_get_uniname_from_ext_entry(sb, p_dir: &clu, entry: i,
156 uniname: uni_name.name);
157 if (err) {
158 brelse(bh);
159 continue;
160 }
161 exfat_utf16_to_nls(sb, uniname: &uni_name,
162 p_cstring: dir_entry->namebuf.lfn,
163 len: dir_entry->namebuf.lfnbuf_len);
164 brelse(bh);
165
166 ep = exfat_get_dentry(sb, p_dir: &clu, entry: i + 1, bh: &bh);
167 if (!ep)
168 return -EIO;
169 dir_entry->size =
170 le64_to_cpu(ep->dentry.stream.valid_size);
171 dir_entry->entry = dentry;
172 brelse(bh);
173
174 ei->hint_bmap.off = EXFAT_DEN_TO_CLU(dentry, sbi);
175 ei->hint_bmap.clu = clu.dir;
176
177 *cpos = EXFAT_DEN_TO_B(dentry + 1 + num_ext);
178 return 0;
179 }
180
181 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
182 if (--clu.size > 0)
183 clu.dir++;
184 else
185 clu.dir = EXFAT_EOF_CLUSTER;
186 } else {
187 if (exfat_get_next_cluster(sb, &(clu.dir)))
188 return -EIO;
189 }
190 }
191
192 dir_entry->namebuf.lfn[0] = '\0';
193 *cpos = EXFAT_DEN_TO_B(dentry);
194 return 0;
195}
196
197static void exfat_init_namebuf(struct exfat_dentry_namebuf *nb)
198{
199 nb->lfn = NULL;
200 nb->lfnbuf_len = 0;
201}
202
203static int exfat_alloc_namebuf(struct exfat_dentry_namebuf *nb)
204{
205 nb->lfn = __getname();
206 if (!nb->lfn)
207 return -ENOMEM;
208 nb->lfnbuf_len = MAX_VFSNAME_BUF_SIZE;
209 return 0;
210}
211
212static void exfat_free_namebuf(struct exfat_dentry_namebuf *nb)
213{
214 if (!nb->lfn)
215 return;
216
217 __putname(nb->lfn);
218 exfat_init_namebuf(nb);
219}
220
221/*
222 * Before calling dir_emit*(), sbi->s_lock should be released
223 * because page fault can occur in dir_emit*().
224 */
225#define ITER_POS_FILLED_DOTS (2)
226static int exfat_iterate(struct file *file, struct dir_context *ctx)
227{
228 struct inode *inode = file_inode(f: file);
229 struct super_block *sb = inode->i_sb;
230 struct inode *tmp;
231 struct exfat_dir_entry de;
232 struct exfat_dentry_namebuf *nb = &(de.namebuf);
233 struct exfat_inode_info *ei = EXFAT_I(inode);
234 unsigned long inum;
235 loff_t cpos, i_pos;
236 int err = 0, fake_offset = 0;
237
238 exfat_init_namebuf(nb);
239
240 cpos = ctx->pos;
241 if (!dir_emit_dots(file, ctx))
242 goto out;
243
244 if (ctx->pos == ITER_POS_FILLED_DOTS) {
245 cpos = 0;
246 fake_offset = 1;
247 }
248
249 cpos = round_up(cpos, DENTRY_SIZE);
250
251 /* name buffer should be allocated before use */
252 err = exfat_alloc_namebuf(nb);
253 if (err)
254 goto out;
255get_new:
256 mutex_lock(&EXFAT_SB(sb)->s_lock);
257
258 if (ei->flags == ALLOC_NO_FAT_CHAIN && cpos >= i_size_read(inode))
259 goto end_of_dir;
260
261 err = exfat_readdir(inode, cpos: &cpos, dir_entry: &de);
262 if (err) {
263 /*
264 * At least we tried to read a sector.
265 * Move cpos to next sector position (should be aligned).
266 */
267 if (err == -EIO) {
268 cpos += 1 << (sb->s_blocksize_bits);
269 cpos &= ~(sb->s_blocksize - 1);
270 }
271
272 err = -EIO;
273 goto end_of_dir;
274 }
275
276 if (!nb->lfn[0])
277 goto end_of_dir;
278
279 i_pos = ((loff_t)ei->start_clu << 32) | (de.entry & 0xffffffff);
280 tmp = exfat_iget(sb, i_pos);
281 if (tmp) {
282 inum = tmp->i_ino;
283 iput(tmp);
284 } else {
285 inum = iunique(sb, EXFAT_ROOT_INO);
286 }
287
288 mutex_unlock(lock: &EXFAT_SB(sb)->s_lock);
289 if (!dir_emit(ctx, name: nb->lfn, strlen(nb->lfn), ino: inum,
290 type: (de.attr & EXFAT_ATTR_SUBDIR) ? DT_DIR : DT_REG))
291 goto out;
292 ctx->pos = cpos;
293 goto get_new;
294
295end_of_dir:
296 if (!cpos && fake_offset)
297 cpos = ITER_POS_FILLED_DOTS;
298 ctx->pos = cpos;
299 mutex_unlock(lock: &EXFAT_SB(sb)->s_lock);
300out:
301 /*
302 * To improve performance, free namebuf after unlock sb_lock.
303 * If namebuf is not allocated, this function do nothing
304 */
305 exfat_free_namebuf(nb);
306 return err;
307}
308
309WRAP_DIR_ITER(exfat_iterate) // FIXME!
310const struct file_operations exfat_dir_operations = {
311 .llseek = generic_file_llseek,
312 .read = generic_read_dir,
313 .iterate_shared = shared_exfat_iterate,
314 .unlocked_ioctl = exfat_ioctl,
315#ifdef CONFIG_COMPAT
316 .compat_ioctl = exfat_compat_ioctl,
317#endif
318 .fsync = exfat_file_fsync,
319};
320
321int exfat_alloc_new_dir(struct inode *inode, struct exfat_chain *clu)
322{
323 int ret;
324
325 exfat_chain_set(ec: clu, EXFAT_EOF_CLUSTER, size: 0, ALLOC_NO_FAT_CHAIN);
326
327 ret = exfat_alloc_cluster(inode, num_alloc: 1, p_chain: clu, IS_DIRSYNC(inode));
328 if (ret)
329 return ret;
330
331 return exfat_zeroed_cluster(dir: inode, clu: clu->dir);
332}
333
334int exfat_calc_num_entries(struct exfat_uni_name *p_uniname)
335{
336 int len;
337
338 len = p_uniname->name_len;
339 if (len == 0)
340 return -EINVAL;
341
342 /* 1 file entry + 1 stream entry + name entries */
343 return ES_ENTRY_NUM(len);
344}
345
346unsigned int exfat_get_entry_type(struct exfat_dentry *ep)
347{
348 if (ep->type == EXFAT_UNUSED)
349 return TYPE_UNUSED;
350 if (IS_EXFAT_DELETED(ep->type))
351 return TYPE_DELETED;
352 if (ep->type == EXFAT_INVAL)
353 return TYPE_INVALID;
354 if (IS_EXFAT_CRITICAL_PRI(ep->type)) {
355 if (ep->type == EXFAT_BITMAP)
356 return TYPE_BITMAP;
357 if (ep->type == EXFAT_UPCASE)
358 return TYPE_UPCASE;
359 if (ep->type == EXFAT_VOLUME)
360 return TYPE_VOLUME;
361 if (ep->type == EXFAT_FILE) {
362 if (le16_to_cpu(ep->dentry.file.attr) & EXFAT_ATTR_SUBDIR)
363 return TYPE_DIR;
364 return TYPE_FILE;
365 }
366 return TYPE_CRITICAL_PRI;
367 }
368 if (IS_EXFAT_BENIGN_PRI(ep->type)) {
369 if (ep->type == EXFAT_GUID)
370 return TYPE_GUID;
371 if (ep->type == EXFAT_PADDING)
372 return TYPE_PADDING;
373 if (ep->type == EXFAT_ACLTAB)
374 return TYPE_ACLTAB;
375 return TYPE_BENIGN_PRI;
376 }
377 if (IS_EXFAT_CRITICAL_SEC(ep->type)) {
378 if (ep->type == EXFAT_STREAM)
379 return TYPE_STREAM;
380 if (ep->type == EXFAT_NAME)
381 return TYPE_EXTEND;
382 if (ep->type == EXFAT_ACL)
383 return TYPE_ACL;
384 return TYPE_CRITICAL_SEC;
385 }
386
387 if (ep->type == EXFAT_VENDOR_EXT)
388 return TYPE_VENDOR_EXT;
389 if (ep->type == EXFAT_VENDOR_ALLOC)
390 return TYPE_VENDOR_ALLOC;
391
392 return TYPE_BENIGN_SEC;
393}
394
395static void exfat_set_entry_type(struct exfat_dentry *ep, unsigned int type)
396{
397 if (type == TYPE_UNUSED) {
398 ep->type = EXFAT_UNUSED;
399 } else if (type == TYPE_DELETED) {
400 ep->type &= EXFAT_DELETE;
401 } else if (type == TYPE_STREAM) {
402 ep->type = EXFAT_STREAM;
403 } else if (type == TYPE_EXTEND) {
404 ep->type = EXFAT_NAME;
405 } else if (type == TYPE_BITMAP) {
406 ep->type = EXFAT_BITMAP;
407 } else if (type == TYPE_UPCASE) {
408 ep->type = EXFAT_UPCASE;
409 } else if (type == TYPE_VOLUME) {
410 ep->type = EXFAT_VOLUME;
411 } else if (type == TYPE_DIR) {
412 ep->type = EXFAT_FILE;
413 ep->dentry.file.attr = cpu_to_le16(EXFAT_ATTR_SUBDIR);
414 } else if (type == TYPE_FILE) {
415 ep->type = EXFAT_FILE;
416 ep->dentry.file.attr = cpu_to_le16(EXFAT_ATTR_ARCHIVE);
417 }
418}
419
420static void exfat_init_stream_entry(struct exfat_dentry *ep,
421 unsigned int start_clu, unsigned long long size)
422{
423 exfat_set_entry_type(ep, TYPE_STREAM);
424 if (size == 0)
425 ep->dentry.stream.flags = ALLOC_FAT_CHAIN;
426 else
427 ep->dentry.stream.flags = ALLOC_NO_FAT_CHAIN;
428 ep->dentry.stream.start_clu = cpu_to_le32(start_clu);
429 ep->dentry.stream.valid_size = cpu_to_le64(size);
430 ep->dentry.stream.size = cpu_to_le64(size);
431}
432
433static void exfat_init_name_entry(struct exfat_dentry *ep,
434 unsigned short *uniname)
435{
436 int i;
437
438 exfat_set_entry_type(ep, TYPE_EXTEND);
439 ep->dentry.name.flags = 0x0;
440
441 for (i = 0; i < EXFAT_FILE_NAME_LEN; i++) {
442 if (*uniname != 0x0) {
443 ep->dentry.name.unicode_0_14[i] = cpu_to_le16(*uniname);
444 uniname++;
445 } else {
446 ep->dentry.name.unicode_0_14[i] = 0x0;
447 }
448 }
449}
450
451void exfat_init_dir_entry(struct exfat_entry_set_cache *es,
452 unsigned int type, unsigned int start_clu,
453 unsigned long long size, struct timespec64 *ts)
454{
455 struct super_block *sb = es->sb;
456 struct exfat_sb_info *sbi = EXFAT_SB(sb);
457 struct exfat_dentry *ep;
458
459 ep = exfat_get_dentry_cached(es, ES_IDX_FILE);
460 exfat_set_entry_type(ep, type);
461 exfat_set_entry_time(sbi, ts,
462 tz: &ep->dentry.file.create_tz,
463 time: &ep->dentry.file.create_time,
464 date: &ep->dentry.file.create_date,
465 time_cs: &ep->dentry.file.create_time_cs);
466 exfat_set_entry_time(sbi, ts,
467 tz: &ep->dentry.file.modify_tz,
468 time: &ep->dentry.file.modify_time,
469 date: &ep->dentry.file.modify_date,
470 time_cs: &ep->dentry.file.modify_time_cs);
471 exfat_set_entry_time(sbi, ts,
472 tz: &ep->dentry.file.access_tz,
473 time: &ep->dentry.file.access_time,
474 date: &ep->dentry.file.access_date,
475 NULL);
476
477 ep = exfat_get_dentry_cached(es, ES_IDX_STREAM);
478 exfat_init_stream_entry(ep, start_clu, size);
479}
480
481static void exfat_free_benign_secondary_clusters(struct inode *inode,
482 struct exfat_dentry *ep)
483{
484 struct super_block *sb = inode->i_sb;
485 struct exfat_chain dir;
486 unsigned int start_clu =
487 le32_to_cpu(ep->dentry.generic_secondary.start_clu);
488 u64 size = le64_to_cpu(ep->dentry.generic_secondary.size);
489 unsigned char flags = ep->dentry.generic_secondary.flags;
490
491 if (!(flags & ALLOC_POSSIBLE) || !start_clu || !size)
492 return;
493
494 exfat_chain_set(ec: &dir, dir: start_clu,
495 EXFAT_B_TO_CLU_ROUND_UP(size, EXFAT_SB(sb)),
496 flags);
497 exfat_free_cluster(inode, p_chain: &dir);
498}
499
500void exfat_init_ext_entry(struct exfat_entry_set_cache *es, int num_entries,
501 struct exfat_uni_name *p_uniname)
502{
503 int i;
504 unsigned short *uniname = p_uniname->name;
505 struct exfat_dentry *ep;
506
507 ep = exfat_get_dentry_cached(es, ES_IDX_FILE);
508 ep->dentry.file.num_ext = (unsigned char)(num_entries - 1);
509
510 ep = exfat_get_dentry_cached(es, ES_IDX_STREAM);
511 ep->dentry.stream.name_len = p_uniname->name_len;
512 ep->dentry.stream.name_hash = cpu_to_le16(p_uniname->name_hash);
513
514 for (i = ES_IDX_FIRST_FILENAME; i < num_entries; i++) {
515 ep = exfat_get_dentry_cached(es, num: i);
516 exfat_init_name_entry(ep, uniname);
517 uniname += EXFAT_FILE_NAME_LEN;
518 }
519
520 exfat_update_dir_chksum(es);
521}
522
523void exfat_remove_entries(struct inode *inode, struct exfat_entry_set_cache *es,
524 int order)
525{
526 int i;
527 struct exfat_dentry *ep;
528
529 for (i = order; i < es->num_entries; i++) {
530 ep = exfat_get_dentry_cached(es, num: i);
531
532 if (exfat_get_entry_type(ep) & TYPE_BENIGN_SEC)
533 exfat_free_benign_secondary_clusters(inode, ep);
534
535 exfat_set_entry_type(ep, TYPE_DELETED);
536 }
537
538 if (order < es->num_entries)
539 es->modified = true;
540}
541
542void exfat_update_dir_chksum(struct exfat_entry_set_cache *es)
543{
544 int chksum_type = CS_DIR_ENTRY, i;
545 unsigned short chksum = 0;
546 struct exfat_dentry *ep;
547
548 for (i = ES_IDX_FILE; i < es->num_entries; i++) {
549 ep = exfat_get_dentry_cached(es, num: i);
550 chksum = exfat_calc_chksum16(data: ep, DENTRY_SIZE, chksum,
551 type: chksum_type);
552 chksum_type = CS_DEFAULT;
553 }
554 ep = exfat_get_dentry_cached(es, ES_IDX_FILE);
555 ep->dentry.file.checksum = cpu_to_le16(chksum);
556 es->modified = true;
557}
558
559int exfat_put_dentry_set(struct exfat_entry_set_cache *es, int sync)
560{
561 int i, err = 0;
562
563 if (es->modified)
564 err = exfat_update_bhs(bhs: es->bh, nr_bhs: es->num_bh, sync);
565
566 for (i = 0; i < es->num_bh; i++)
567 if (err)
568 bforget(bh: es->bh[i]);
569 else
570 brelse(bh: es->bh[i]);
571
572 if (IS_DYNAMIC_ES(es))
573 kfree(objp: es->bh);
574
575 return err;
576}
577
578static int exfat_walk_fat_chain(struct super_block *sb,
579 struct exfat_chain *p_dir, unsigned int byte_offset,
580 unsigned int *clu)
581{
582 struct exfat_sb_info *sbi = EXFAT_SB(sb);
583 unsigned int clu_offset;
584 unsigned int cur_clu;
585
586 clu_offset = EXFAT_B_TO_CLU(byte_offset, sbi);
587 cur_clu = p_dir->dir;
588
589 if (p_dir->flags == ALLOC_NO_FAT_CHAIN) {
590 cur_clu += clu_offset;
591 } else {
592 while (clu_offset > 0) {
593 if (exfat_get_next_cluster(sb, &cur_clu))
594 return -EIO;
595 if (cur_clu == EXFAT_EOF_CLUSTER) {
596 exfat_fs_error(sb,
597 "invalid dentry access beyond EOF (clu : %u, eidx : %d)",
598 p_dir->dir,
599 EXFAT_B_TO_DEN(byte_offset));
600 return -EIO;
601 }
602 clu_offset--;
603 }
604 }
605
606 *clu = cur_clu;
607 return 0;
608}
609
610static int exfat_find_location(struct super_block *sb, struct exfat_chain *p_dir,
611 int entry, sector_t *sector, int *offset)
612{
613 int ret;
614 unsigned int off, clu = 0;
615 struct exfat_sb_info *sbi = EXFAT_SB(sb);
616
617 off = EXFAT_DEN_TO_B(entry);
618
619 ret = exfat_walk_fat_chain(sb, p_dir, byte_offset: off, clu: &clu);
620 if (ret)
621 return ret;
622
623 /* byte offset in cluster */
624 off = EXFAT_CLU_OFFSET(off, sbi);
625
626 /* byte offset in sector */
627 *offset = EXFAT_BLK_OFFSET(off, sb);
628
629 /* sector offset in cluster */
630 *sector = EXFAT_B_TO_BLK(off, sb);
631 *sector += exfat_cluster_to_sector(sbi, clus: clu);
632 return 0;
633}
634
635#define EXFAT_MAX_RA_SIZE (128*1024)
636static int exfat_dir_readahead(struct super_block *sb, sector_t sec)
637{
638 struct exfat_sb_info *sbi = EXFAT_SB(sb);
639 struct buffer_head *bh;
640 unsigned int max_ra_count = EXFAT_MAX_RA_SIZE >> sb->s_blocksize_bits;
641 unsigned int page_ra_count = PAGE_SIZE >> sb->s_blocksize_bits;
642 unsigned int adj_ra_count = max(sbi->sect_per_clus, page_ra_count);
643 unsigned int ra_count = min(adj_ra_count, max_ra_count);
644
645 /* Read-ahead is not required */
646 if (sbi->sect_per_clus == 1)
647 return 0;
648
649 if (sec < sbi->data_start_sector) {
650 exfat_err(sb, "requested sector is invalid(sect:%llu, root:%llu)",
651 (unsigned long long)sec, sbi->data_start_sector);
652 return -EIO;
653 }
654
655 /* Not sector aligned with ra_count, resize ra_count to page size */
656 if ((sec - sbi->data_start_sector) & (ra_count - 1))
657 ra_count = page_ra_count;
658
659 bh = sb_find_get_block(sb, block: sec);
660 if (!bh || !buffer_uptodate(bh)) {
661 unsigned int i;
662
663 for (i = 0; i < ra_count; i++)
664 sb_breadahead(sb, block: (sector_t)(sec + i));
665 }
666 brelse(bh);
667 return 0;
668}
669
670struct exfat_dentry *exfat_get_dentry(struct super_block *sb,
671 struct exfat_chain *p_dir, int entry, struct buffer_head **bh)
672{
673 unsigned int dentries_per_page = EXFAT_B_TO_DEN(PAGE_SIZE);
674 int off;
675 sector_t sec;
676
677 if (p_dir->dir == DIR_DELETED) {
678 exfat_err(sb, "abnormal access to deleted dentry");
679 return NULL;
680 }
681
682 if (exfat_find_location(sb, p_dir, entry, sector: &sec, offset: &off))
683 return NULL;
684
685 if (p_dir->dir != EXFAT_FREE_CLUSTER &&
686 !(entry & (dentries_per_page - 1)))
687 exfat_dir_readahead(sb, sec);
688
689 *bh = sb_bread(sb, block: sec);
690 if (!*bh)
691 return NULL;
692
693 return (struct exfat_dentry *)((*bh)->b_data + off);
694}
695
696enum exfat_validate_dentry_mode {
697 ES_MODE_GET_FILE_ENTRY,
698 ES_MODE_GET_STRM_ENTRY,
699 ES_MODE_GET_NAME_ENTRY,
700 ES_MODE_GET_CRITICAL_SEC_ENTRY,
701 ES_MODE_GET_BENIGN_SEC_ENTRY,
702};
703
704static bool exfat_validate_entry(unsigned int type,
705 enum exfat_validate_dentry_mode *mode)
706{
707 if (type == TYPE_UNUSED || type == TYPE_DELETED)
708 return false;
709
710 switch (*mode) {
711 case ES_MODE_GET_FILE_ENTRY:
712 if (type != TYPE_STREAM)
713 return false;
714 *mode = ES_MODE_GET_STRM_ENTRY;
715 break;
716 case ES_MODE_GET_STRM_ENTRY:
717 if (type != TYPE_EXTEND)
718 return false;
719 *mode = ES_MODE_GET_NAME_ENTRY;
720 break;
721 case ES_MODE_GET_NAME_ENTRY:
722 if (type & TYPE_BENIGN_SEC)
723 *mode = ES_MODE_GET_BENIGN_SEC_ENTRY;
724 else if (type != TYPE_EXTEND)
725 return false;
726 break;
727 case ES_MODE_GET_BENIGN_SEC_ENTRY:
728 /* Assume unreconized benign secondary entry */
729 if (!(type & TYPE_BENIGN_SEC))
730 return false;
731 break;
732 default:
733 return false;
734 }
735
736 return true;
737}
738
739struct exfat_dentry *exfat_get_dentry_cached(
740 struct exfat_entry_set_cache *es, int num)
741{
742 int off = es->start_off + num * DENTRY_SIZE;
743 struct buffer_head *bh = es->bh[EXFAT_B_TO_BLK(off, es->sb)];
744 char *p = bh->b_data + EXFAT_BLK_OFFSET(off, es->sb);
745
746 return (struct exfat_dentry *)p;
747}
748
749/*
750 * Returns a set of dentries.
751 *
752 * Note It provides a direct pointer to bh->data via exfat_get_dentry_cached().
753 * User should call exfat_get_dentry_set() after setting 'modified' to apply
754 * changes made in this entry set to the real device.
755 *
756 * in:
757 * sb+p_dir+entry: indicates a file/dir
758 * num_entries: specifies how many dentries should be included.
759 * It will be set to es->num_entries if it is not 0.
760 * If num_entries is 0, es->num_entries will be obtained
761 * from the first dentry.
762 * out:
763 * es: pointer of entry set on success.
764 * return:
765 * 0 on success
766 * -error code on failure
767 */
768static int __exfat_get_dentry_set(struct exfat_entry_set_cache *es,
769 struct super_block *sb, struct exfat_chain *p_dir, int entry,
770 unsigned int num_entries)
771{
772 int ret, i, num_bh;
773 unsigned int off;
774 sector_t sec;
775 struct exfat_sb_info *sbi = EXFAT_SB(sb);
776 struct buffer_head *bh;
777
778 if (p_dir->dir == DIR_DELETED) {
779 exfat_err(sb, "access to deleted dentry");
780 return -EIO;
781 }
782
783 ret = exfat_find_location(sb, p_dir, entry, sector: &sec, offset: &off);
784 if (ret)
785 return ret;
786
787 memset(es, 0, sizeof(*es));
788 es->sb = sb;
789 es->modified = false;
790 es->start_off = off;
791 es->bh = es->__bh;
792
793 bh = sb_bread(sb, block: sec);
794 if (!bh)
795 return -EIO;
796 es->bh[es->num_bh++] = bh;
797
798 if (num_entries == ES_ALL_ENTRIES) {
799 struct exfat_dentry *ep;
800
801 ep = exfat_get_dentry_cached(es, ES_IDX_FILE);
802 if (ep->type != EXFAT_FILE) {
803 brelse(bh);
804 return -EIO;
805 }
806
807 num_entries = ep->dentry.file.num_ext + 1;
808 }
809
810 es->num_entries = num_entries;
811
812 num_bh = EXFAT_B_TO_BLK_ROUND_UP(off + num_entries * DENTRY_SIZE, sb);
813 if (num_bh > ARRAY_SIZE(es->__bh)) {
814 es->bh = kmalloc_array(n: num_bh, size: sizeof(*es->bh), GFP_KERNEL);
815 if (!es->bh) {
816 brelse(bh);
817 return -ENOMEM;
818 }
819 es->bh[0] = bh;
820 }
821
822 for (i = 1; i < num_bh; i++) {
823 /* get the next sector */
824 if (exfat_is_last_sector_in_cluster(sbi, sec)) {
825 unsigned int clu = exfat_sector_to_cluster(sbi, sec);
826
827 if (p_dir->flags == ALLOC_NO_FAT_CHAIN)
828 clu++;
829 else if (exfat_get_next_cluster(sb, &clu))
830 goto put_es;
831 sec = exfat_cluster_to_sector(sbi, clus: clu);
832 } else {
833 sec++;
834 }
835
836 bh = sb_bread(sb, block: sec);
837 if (!bh)
838 goto put_es;
839 es->bh[es->num_bh++] = bh;
840 }
841
842 return 0;
843
844put_es:
845 exfat_put_dentry_set(es, sync: false);
846 return -EIO;
847}
848
849int exfat_get_dentry_set(struct exfat_entry_set_cache *es,
850 struct super_block *sb, struct exfat_chain *p_dir,
851 int entry, unsigned int num_entries)
852{
853 int ret, i;
854 struct exfat_dentry *ep;
855 enum exfat_validate_dentry_mode mode = ES_MODE_GET_FILE_ENTRY;
856
857 ret = __exfat_get_dentry_set(es, sb, p_dir, entry, num_entries);
858 if (ret < 0)
859 return ret;
860
861 /* validate cached dentries */
862 for (i = ES_IDX_STREAM; i < es->num_entries; i++) {
863 ep = exfat_get_dentry_cached(es, num: i);
864 if (!exfat_validate_entry(type: exfat_get_entry_type(ep), mode: &mode))
865 goto put_es;
866 }
867 return 0;
868
869put_es:
870 exfat_put_dentry_set(es, sync: false);
871 return -EIO;
872}
873
874static int exfat_validate_empty_dentry_set(struct exfat_entry_set_cache *es)
875{
876 struct exfat_dentry *ep;
877 struct buffer_head *bh;
878 int i, off;
879 bool unused_hit = false;
880
881 /*
882 * ONLY UNUSED OR DELETED DENTRIES ARE ALLOWED:
883 * Although it violates the specification for a deleted entry to
884 * follow an unused entry, some exFAT implementations could work
885 * like this. Therefore, to improve compatibility, let's allow it.
886 */
887 for (i = 0; i < es->num_entries; i++) {
888 ep = exfat_get_dentry_cached(es, num: i);
889 if (ep->type == EXFAT_UNUSED) {
890 unused_hit = true;
891 } else if (!IS_EXFAT_DELETED(ep->type)) {
892 if (unused_hit)
893 goto err_used_follow_unused;
894 i++;
895 goto count_skip_entries;
896 }
897 }
898
899 return 0;
900
901err_used_follow_unused:
902 off = es->start_off + (i << DENTRY_SIZE_BITS);
903 bh = es->bh[EXFAT_B_TO_BLK(off, es->sb)];
904
905 exfat_fs_error(es->sb,
906 "in sector %lld, dentry %d should be unused, but 0x%x",
907 bh->b_blocknr, off >> DENTRY_SIZE_BITS, ep->type);
908
909 return -EIO;
910
911count_skip_entries:
912 es->num_entries = EXFAT_B_TO_DEN(EXFAT_BLK_TO_B(es->num_bh, es->sb) - es->start_off);
913 for (; i < es->num_entries; i++) {
914 ep = exfat_get_dentry_cached(es, num: i);
915 if (IS_EXFAT_DELETED(ep->type))
916 break;
917 }
918
919 return i;
920}
921
922/*
923 * Get an empty dentry set.
924 *
925 * in:
926 * sb+p_dir+entry: indicates the empty dentry location
927 * num_entries: specifies how many empty dentries should be included.
928 * out:
929 * es: pointer of empty dentry set on success.
930 * return:
931 * 0 : on success
932 * >0 : the dentries are not empty, the return value is the number of
933 * dentries to be skipped for the next lookup.
934 * <0 : on failure
935 */
936int exfat_get_empty_dentry_set(struct exfat_entry_set_cache *es,
937 struct super_block *sb, struct exfat_chain *p_dir,
938 int entry, unsigned int num_entries)
939{
940 int ret;
941
942 ret = __exfat_get_dentry_set(es, sb, p_dir, entry, num_entries);
943 if (ret < 0)
944 return ret;
945
946 ret = exfat_validate_empty_dentry_set(es);
947 if (ret)
948 exfat_put_dentry_set(es, sync: false);
949
950 return ret;
951}
952
953static inline void exfat_reset_empty_hint(struct exfat_hint_femp *hint_femp)
954{
955 hint_femp->eidx = EXFAT_HINT_NONE;
956 hint_femp->count = 0;
957}
958
959static inline void exfat_set_empty_hint(struct exfat_inode_info *ei,
960 struct exfat_hint_femp *candi_empty, struct exfat_chain *clu,
961 int dentry, int num_entries, int entry_type)
962{
963 if (ei->hint_femp.eidx == EXFAT_HINT_NONE ||
964 ei->hint_femp.eidx > dentry) {
965 int total_entries = EXFAT_B_TO_DEN(i_size_read(&ei->vfs_inode));
966
967 if (candi_empty->count == 0) {
968 candi_empty->cur = *clu;
969 candi_empty->eidx = dentry;
970 }
971
972 if (entry_type == TYPE_UNUSED)
973 candi_empty->count += total_entries - dentry;
974 else
975 candi_empty->count++;
976
977 if (candi_empty->count == num_entries ||
978 candi_empty->count + candi_empty->eidx == total_entries)
979 ei->hint_femp = *candi_empty;
980 }
981}
982
983enum {
984 DIRENT_STEP_FILE,
985 DIRENT_STEP_STRM,
986 DIRENT_STEP_NAME,
987 DIRENT_STEP_SECD,
988};
989
990/*
991 * @ei: inode info of parent directory
992 * @p_dir: directory structure of parent directory
993 * @num_entries:entry size of p_uniname
994 * @hint_opt: If p_uniname is found, filled with optimized dir/entry
995 * for traversing cluster chain.
996 * @return:
997 * >= 0: file directory entry position where the name exists
998 * -ENOENT: entry with the name does not exist
999 * -EIO: I/O error
1000 */
1001int exfat_find_dir_entry(struct super_block *sb, struct exfat_inode_info *ei,
1002 struct exfat_chain *p_dir, struct exfat_uni_name *p_uniname,
1003 struct exfat_hint *hint_opt)
1004{
1005 int i, rewind = 0, dentry = 0, end_eidx = 0, num_ext = 0, len;
1006 int order, step, name_len = 0;
1007 int dentries_per_clu;
1008 unsigned int entry_type;
1009 unsigned short *uniname = NULL;
1010 struct exfat_chain clu;
1011 struct exfat_hint *hint_stat = &ei->hint_stat;
1012 struct exfat_hint_femp candi_empty;
1013 struct exfat_sb_info *sbi = EXFAT_SB(sb);
1014 int num_entries = exfat_calc_num_entries(p_uniname);
1015
1016 if (num_entries < 0)
1017 return num_entries;
1018
1019 dentries_per_clu = sbi->dentries_per_clu;
1020
1021 exfat_chain_dup(dup: &clu, ec: p_dir);
1022
1023 if (hint_stat->eidx) {
1024 clu.dir = hint_stat->clu;
1025 dentry = hint_stat->eidx;
1026 end_eidx = dentry;
1027 }
1028
1029 exfat_reset_empty_hint(hint_femp: &ei->hint_femp);
1030
1031rewind:
1032 order = 0;
1033 step = DIRENT_STEP_FILE;
1034 exfat_reset_empty_hint(hint_femp: &candi_empty);
1035
1036 while (clu.dir != EXFAT_EOF_CLUSTER) {
1037 i = dentry & (dentries_per_clu - 1);
1038 for (; i < dentries_per_clu; i++, dentry++) {
1039 struct exfat_dentry *ep;
1040 struct buffer_head *bh;
1041
1042 if (rewind && dentry == end_eidx)
1043 goto not_found;
1044
1045 ep = exfat_get_dentry(sb, p_dir: &clu, entry: i, bh: &bh);
1046 if (!ep)
1047 return -EIO;
1048
1049 entry_type = exfat_get_entry_type(ep);
1050
1051 if (entry_type == TYPE_UNUSED ||
1052 entry_type == TYPE_DELETED) {
1053 step = DIRENT_STEP_FILE;
1054
1055 exfat_set_empty_hint(ei, candi_empty: &candi_empty, clu: &clu,
1056 dentry, num_entries,
1057 entry_type);
1058
1059 brelse(bh);
1060 if (entry_type == TYPE_UNUSED)
1061 goto not_found;
1062 continue;
1063 }
1064
1065 exfat_reset_empty_hint(hint_femp: &candi_empty);
1066
1067 if (entry_type == TYPE_FILE || entry_type == TYPE_DIR) {
1068 step = DIRENT_STEP_FILE;
1069 hint_opt->clu = clu.dir;
1070 hint_opt->eidx = i;
1071 num_ext = ep->dentry.file.num_ext;
1072 step = DIRENT_STEP_STRM;
1073 brelse(bh);
1074 continue;
1075 }
1076
1077 if (entry_type == TYPE_STREAM) {
1078 u16 name_hash;
1079
1080 if (step != DIRENT_STEP_STRM) {
1081 step = DIRENT_STEP_FILE;
1082 brelse(bh);
1083 continue;
1084 }
1085 step = DIRENT_STEP_FILE;
1086 name_hash = le16_to_cpu(
1087 ep->dentry.stream.name_hash);
1088 if (p_uniname->name_hash == name_hash &&
1089 p_uniname->name_len ==
1090 ep->dentry.stream.name_len) {
1091 step = DIRENT_STEP_NAME;
1092 order = 1;
1093 name_len = 0;
1094 }
1095 brelse(bh);
1096 continue;
1097 }
1098
1099 brelse(bh);
1100 if (entry_type == TYPE_EXTEND) {
1101 unsigned short entry_uniname[16], unichar;
1102
1103 if (step != DIRENT_STEP_NAME ||
1104 name_len >= MAX_NAME_LENGTH) {
1105 step = DIRENT_STEP_FILE;
1106 continue;
1107 }
1108
1109 if (++order == 2)
1110 uniname = p_uniname->name;
1111 else
1112 uniname += EXFAT_FILE_NAME_LEN;
1113
1114 len = exfat_extract_uni_name(ep, uniname: entry_uniname);
1115 name_len += len;
1116
1117 unichar = *(uniname+len);
1118 *(uniname+len) = 0x0;
1119
1120 if (exfat_uniname_ncmp(sb, a: uniname,
1121 b: entry_uniname, len)) {
1122 step = DIRENT_STEP_FILE;
1123 } else if (p_uniname->name_len == name_len) {
1124 if (order == num_ext)
1125 goto found;
1126 step = DIRENT_STEP_SECD;
1127 }
1128
1129 *(uniname+len) = unichar;
1130 continue;
1131 }
1132
1133 if (entry_type &
1134 (TYPE_CRITICAL_SEC | TYPE_BENIGN_SEC)) {
1135 if (step == DIRENT_STEP_SECD) {
1136 if (++order == num_ext)
1137 goto found;
1138 continue;
1139 }
1140 }
1141 step = DIRENT_STEP_FILE;
1142 }
1143
1144 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1145 if (--clu.size > 0)
1146 clu.dir++;
1147 else
1148 clu.dir = EXFAT_EOF_CLUSTER;
1149 } else {
1150 if (exfat_get_next_cluster(sb, &clu.dir))
1151 return -EIO;
1152 }
1153 }
1154
1155not_found:
1156 /*
1157 * We started at not 0 index,so we should try to find target
1158 * from 0 index to the index we started at.
1159 */
1160 if (!rewind && end_eidx) {
1161 rewind = 1;
1162 dentry = 0;
1163 clu.dir = p_dir->dir;
1164 goto rewind;
1165 }
1166
1167 /*
1168 * set the EXFAT_EOF_CLUSTER flag to avoid search
1169 * from the beginning again when allocated a new cluster
1170 */
1171 if (ei->hint_femp.eidx == EXFAT_HINT_NONE) {
1172 ei->hint_femp.cur.dir = EXFAT_EOF_CLUSTER;
1173 ei->hint_femp.eidx = p_dir->size * dentries_per_clu;
1174 ei->hint_femp.count = 0;
1175 }
1176
1177 /* initialized hint_stat */
1178 hint_stat->clu = p_dir->dir;
1179 hint_stat->eidx = 0;
1180 return -ENOENT;
1181
1182found:
1183 /* next dentry we'll find is out of this cluster */
1184 if (!((dentry + 1) & (dentries_per_clu - 1))) {
1185 int ret = 0;
1186
1187 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1188 if (--clu.size > 0)
1189 clu.dir++;
1190 else
1191 clu.dir = EXFAT_EOF_CLUSTER;
1192 } else {
1193 ret = exfat_get_next_cluster(sb, &clu.dir);
1194 }
1195
1196 if (ret || clu.dir == EXFAT_EOF_CLUSTER) {
1197 /* just initialized hint_stat */
1198 hint_stat->clu = p_dir->dir;
1199 hint_stat->eidx = 0;
1200 return (dentry - num_ext);
1201 }
1202 }
1203
1204 hint_stat->clu = clu.dir;
1205 hint_stat->eidx = dentry + 1;
1206 return dentry - num_ext;
1207}
1208
1209int exfat_count_dir_entries(struct super_block *sb, struct exfat_chain *p_dir)
1210{
1211 int i, count = 0;
1212 int dentries_per_clu;
1213 unsigned int entry_type;
1214 struct exfat_chain clu;
1215 struct exfat_dentry *ep;
1216 struct exfat_sb_info *sbi = EXFAT_SB(sb);
1217 struct buffer_head *bh;
1218
1219 dentries_per_clu = sbi->dentries_per_clu;
1220
1221 exfat_chain_dup(dup: &clu, ec: p_dir);
1222
1223 while (clu.dir != EXFAT_EOF_CLUSTER) {
1224 for (i = 0; i < dentries_per_clu; i++) {
1225 ep = exfat_get_dentry(sb, p_dir: &clu, entry: i, bh: &bh);
1226 if (!ep)
1227 return -EIO;
1228 entry_type = exfat_get_entry_type(ep);
1229 brelse(bh);
1230
1231 if (entry_type == TYPE_UNUSED)
1232 return count;
1233 if (entry_type != TYPE_DIR)
1234 continue;
1235 count++;
1236 }
1237
1238 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1239 if (--clu.size > 0)
1240 clu.dir++;
1241 else
1242 clu.dir = EXFAT_EOF_CLUSTER;
1243 } else {
1244 if (exfat_get_next_cluster(sb, &(clu.dir)))
1245 return -EIO;
1246 }
1247 }
1248
1249 return count;
1250}
1251

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