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

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