GNU Linux-libre 5.19-rc6-gnu
[releases.git] / fs / exfat / dir.c
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
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
32 static void 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;
36         struct exfat_entry_set_cache *es;
37
38         es = exfat_get_dentry_set(sb, p_dir, entry, ES_ALL_ENTRIES);
39         if (!es)
40                 return;
41
42         /*
43          * First entry  : file entry
44          * Second entry : stream-extension entry
45          * Third entry  : first file-name entry
46          * So, the index of first file-name dentry should start from 2.
47          */
48         for (i = 2; i < es->num_entries; i++) {
49                 struct exfat_dentry *ep = exfat_get_dentry_cached(es, i);
50
51                 /* end of name entry */
52                 if (exfat_get_entry_type(ep) != TYPE_EXTEND)
53                         break;
54
55                 exfat_extract_uni_name(ep, uniname);
56                 uniname += EXFAT_FILE_NAME_LEN;
57         }
58
59         exfat_free_dentry_set(es, false);
60 }
61
62 /* read a directory entry from the opened directory */
63 static int exfat_readdir(struct inode *inode, loff_t *cpos, struct exfat_dir_entry *dir_entry)
64 {
65         int i, dentries_per_clu, dentries_per_clu_bits = 0, num_ext;
66         unsigned int type, clu_offset, max_dentries;
67         struct exfat_chain dir, clu;
68         struct exfat_uni_name uni_name;
69         struct exfat_dentry *ep;
70         struct super_block *sb = inode->i_sb;
71         struct exfat_sb_info *sbi = EXFAT_SB(sb);
72         struct exfat_inode_info *ei = EXFAT_I(inode);
73         unsigned int dentry = EXFAT_B_TO_DEN(*cpos) & 0xFFFFFFFF;
74         struct buffer_head *bh;
75
76         /* check if the given file ID is opened */
77         if (ei->type != TYPE_DIR)
78                 return -EPERM;
79
80         if (ei->entry == -1)
81                 exfat_chain_set(&dir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
82         else
83                 exfat_chain_set(&dir, ei->start_clu,
84                         EXFAT_B_TO_CLU(i_size_read(inode), sbi), ei->flags);
85
86         dentries_per_clu = sbi->dentries_per_clu;
87         dentries_per_clu_bits = ilog2(dentries_per_clu);
88         max_dentries = (unsigned int)min_t(u64, MAX_EXFAT_DENTRIES,
89                                            (u64)sbi->num_clusters << dentries_per_clu_bits);
90
91         clu_offset = dentry >> dentries_per_clu_bits;
92         exfat_chain_dup(&clu, &dir);
93
94         if (clu.flags == ALLOC_NO_FAT_CHAIN) {
95                 clu.dir += clu_offset;
96                 clu.size -= clu_offset;
97         } else {
98                 /* hint_information */
99                 if (clu_offset > 0 && ei->hint_bmap.off != EXFAT_EOF_CLUSTER &&
100                     ei->hint_bmap.off > 0 && clu_offset >= ei->hint_bmap.off) {
101                         clu_offset -= ei->hint_bmap.off;
102                         clu.dir = ei->hint_bmap.clu;
103                 }
104
105                 while (clu_offset > 0) {
106                         if (exfat_get_next_cluster(sb, &(clu.dir)))
107                                 return -EIO;
108
109                         clu_offset--;
110                 }
111         }
112
113         while (clu.dir != EXFAT_EOF_CLUSTER && dentry < max_dentries) {
114                 i = dentry & (dentries_per_clu - 1);
115
116                 for ( ; i < dentries_per_clu; i++, dentry++) {
117                         ep = exfat_get_dentry(sb, &clu, i, &bh);
118                         if (!ep)
119                                 return -EIO;
120
121                         type = exfat_get_entry_type(ep);
122                         if (type == TYPE_UNUSED) {
123                                 brelse(bh);
124                                 break;
125                         }
126
127                         if (type != TYPE_FILE && type != TYPE_DIR) {
128                                 brelse(bh);
129                                 continue;
130                         }
131
132                         num_ext = ep->dentry.file.num_ext;
133                         dir_entry->attr = le16_to_cpu(ep->dentry.file.attr);
134                         exfat_get_entry_time(sbi, &dir_entry->crtime,
135                                         ep->dentry.file.create_tz,
136                                         ep->dentry.file.create_time,
137                                         ep->dentry.file.create_date,
138                                         ep->dentry.file.create_time_cs);
139                         exfat_get_entry_time(sbi, &dir_entry->mtime,
140                                         ep->dentry.file.modify_tz,
141                                         ep->dentry.file.modify_time,
142                                         ep->dentry.file.modify_date,
143                                         ep->dentry.file.modify_time_cs);
144                         exfat_get_entry_time(sbi, &dir_entry->atime,
145                                         ep->dentry.file.access_tz,
146                                         ep->dentry.file.access_time,
147                                         ep->dentry.file.access_date,
148                                         0);
149
150                         *uni_name.name = 0x0;
151                         exfat_get_uniname_from_ext_entry(sb, &clu, i,
152                                 uni_name.name);
153                         exfat_utf16_to_nls(sb, &uni_name,
154                                 dir_entry->namebuf.lfn,
155                                 dir_entry->namebuf.lfnbuf_len);
156                         brelse(bh);
157
158                         ep = exfat_get_dentry(sb, &clu, i + 1, &bh);
159                         if (!ep)
160                                 return -EIO;
161                         dir_entry->size =
162                                 le64_to_cpu(ep->dentry.stream.valid_size);
163                         dir_entry->entry = dentry;
164                         brelse(bh);
165
166                         ei->hint_bmap.off = dentry >> dentries_per_clu_bits;
167                         ei->hint_bmap.clu = clu.dir;
168
169                         *cpos = EXFAT_DEN_TO_B(dentry + 1 + num_ext);
170                         return 0;
171                 }
172
173                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
174                         if (--clu.size > 0)
175                                 clu.dir++;
176                         else
177                                 clu.dir = EXFAT_EOF_CLUSTER;
178                 } else {
179                         if (exfat_get_next_cluster(sb, &(clu.dir)))
180                                 return -EIO;
181                 }
182         }
183
184         dir_entry->namebuf.lfn[0] = '\0';
185         *cpos = EXFAT_DEN_TO_B(dentry);
186         return 0;
187 }
188
189 static void exfat_init_namebuf(struct exfat_dentry_namebuf *nb)
190 {
191         nb->lfn = NULL;
192         nb->lfnbuf_len = 0;
193 }
194
195 static int exfat_alloc_namebuf(struct exfat_dentry_namebuf *nb)
196 {
197         nb->lfn = __getname();
198         if (!nb->lfn)
199                 return -ENOMEM;
200         nb->lfnbuf_len = MAX_VFSNAME_BUF_SIZE;
201         return 0;
202 }
203
204 static void exfat_free_namebuf(struct exfat_dentry_namebuf *nb)
205 {
206         if (!nb->lfn)
207                 return;
208
209         __putname(nb->lfn);
210         exfat_init_namebuf(nb);
211 }
212
213 /* skip iterating emit_dots when dir is empty */
214 #define ITER_POS_FILLED_DOTS    (2)
215 static int exfat_iterate(struct file *filp, struct dir_context *ctx)
216 {
217         struct inode *inode = filp->f_path.dentry->d_inode;
218         struct super_block *sb = inode->i_sb;
219         struct inode *tmp;
220         struct exfat_dir_entry de;
221         struct exfat_dentry_namebuf *nb = &(de.namebuf);
222         struct exfat_inode_info *ei = EXFAT_I(inode);
223         unsigned long inum;
224         loff_t cpos, i_pos;
225         int err = 0, fake_offset = 0;
226
227         exfat_init_namebuf(nb);
228         mutex_lock(&EXFAT_SB(sb)->s_lock);
229
230         cpos = ctx->pos;
231         if (!dir_emit_dots(filp, ctx))
232                 goto unlock;
233
234         if (ctx->pos == ITER_POS_FILLED_DOTS) {
235                 cpos = 0;
236                 fake_offset = 1;
237         }
238
239         if (cpos & (DENTRY_SIZE - 1)) {
240                 err = -ENOENT;
241                 goto unlock;
242         }
243
244         /* name buffer should be allocated before use */
245         err = exfat_alloc_namebuf(nb);
246         if (err)
247                 goto unlock;
248 get_new:
249         if (ei->flags == ALLOC_NO_FAT_CHAIN && cpos >= i_size_read(inode))
250                 goto end_of_dir;
251
252         err = exfat_readdir(inode, &cpos, &de);
253         if (err) {
254                 /*
255                  * At least we tried to read a sector.  Move cpos to next sector
256                  * position (should be aligned).
257                  */
258                 if (err == -EIO) {
259                         cpos += 1 << (sb->s_blocksize_bits);
260                         cpos &= ~(sb->s_blocksize - 1);
261                 }
262
263                 err = -EIO;
264                 goto end_of_dir;
265         }
266
267         if (!nb->lfn[0])
268                 goto end_of_dir;
269
270         i_pos = ((loff_t)ei->start_clu << 32) | (de.entry & 0xffffffff);
271         tmp = exfat_iget(sb, i_pos);
272         if (tmp) {
273                 inum = tmp->i_ino;
274                 iput(tmp);
275         } else {
276                 inum = iunique(sb, EXFAT_ROOT_INO);
277         }
278
279         /*
280          * Before calling dir_emit(), sb_lock should be released.
281          * Because page fault can occur in dir_emit() when the size
282          * of buffer given from user is larger than one page size.
283          */
284         mutex_unlock(&EXFAT_SB(sb)->s_lock);
285         if (!dir_emit(ctx, nb->lfn, strlen(nb->lfn), inum,
286                         (de.attr & ATTR_SUBDIR) ? DT_DIR : DT_REG))
287                 goto out_unlocked;
288         mutex_lock(&EXFAT_SB(sb)->s_lock);
289         ctx->pos = cpos;
290         goto get_new;
291
292 end_of_dir:
293         if (!cpos && fake_offset)
294                 cpos = ITER_POS_FILLED_DOTS;
295         ctx->pos = cpos;
296 unlock:
297         mutex_unlock(&EXFAT_SB(sb)->s_lock);
298 out_unlocked:
299         /*
300          * To improve performance, free namebuf after unlock sb_lock.
301          * If namebuf is not allocated, this function do nothing
302          */
303         exfat_free_namebuf(nb);
304         return err;
305 }
306
307 const struct file_operations exfat_dir_operations = {
308         .llseek         = generic_file_llseek,
309         .read           = generic_read_dir,
310         .iterate        = exfat_iterate,
311         .unlocked_ioctl = exfat_ioctl,
312 #ifdef CONFIG_COMPAT
313         .compat_ioctl = exfat_compat_ioctl,
314 #endif
315         .fsync          = exfat_file_fsync,
316 };
317
318 int exfat_alloc_new_dir(struct inode *inode, struct exfat_chain *clu)
319 {
320         int ret;
321
322         exfat_chain_set(clu, EXFAT_EOF_CLUSTER, 0, ALLOC_NO_FAT_CHAIN);
323
324         ret = exfat_alloc_cluster(inode, 1, clu, IS_DIRSYNC(inode));
325         if (ret)
326                 return ret;
327
328         return exfat_zeroed_cluster(inode, clu->dir);
329 }
330
331 int exfat_calc_num_entries(struct exfat_uni_name *p_uniname)
332 {
333         int len;
334
335         len = p_uniname->name_len;
336         if (len == 0)
337                 return -EINVAL;
338
339         /* 1 file entry + 1 stream entry + name entries */
340         return ((len - 1) / EXFAT_FILE_NAME_LEN + 3);
341 }
342
343 unsigned int exfat_get_entry_type(struct exfat_dentry *ep)
344 {
345         if (ep->type == EXFAT_UNUSED)
346                 return TYPE_UNUSED;
347         if (IS_EXFAT_DELETED(ep->type))
348                 return TYPE_DELETED;
349         if (ep->type == EXFAT_INVAL)
350                 return TYPE_INVALID;
351         if (IS_EXFAT_CRITICAL_PRI(ep->type)) {
352                 if (ep->type == EXFAT_BITMAP)
353                         return TYPE_BITMAP;
354                 if (ep->type == EXFAT_UPCASE)
355                         return TYPE_UPCASE;
356                 if (ep->type == EXFAT_VOLUME)
357                         return TYPE_VOLUME;
358                 if (ep->type == EXFAT_FILE) {
359                         if (le16_to_cpu(ep->dentry.file.attr) & ATTR_SUBDIR)
360                                 return TYPE_DIR;
361                         return TYPE_FILE;
362                 }
363                 return TYPE_CRITICAL_PRI;
364         }
365         if (IS_EXFAT_BENIGN_PRI(ep->type)) {
366                 if (ep->type == EXFAT_GUID)
367                         return TYPE_GUID;
368                 if (ep->type == EXFAT_PADDING)
369                         return TYPE_PADDING;
370                 if (ep->type == EXFAT_ACLTAB)
371                         return TYPE_ACLTAB;
372                 return TYPE_BENIGN_PRI;
373         }
374         if (IS_EXFAT_CRITICAL_SEC(ep->type)) {
375                 if (ep->type == EXFAT_STREAM)
376                         return TYPE_STREAM;
377                 if (ep->type == EXFAT_NAME)
378                         return TYPE_EXTEND;
379                 if (ep->type == EXFAT_ACL)
380                         return TYPE_ACL;
381                 return TYPE_CRITICAL_SEC;
382         }
383         return TYPE_BENIGN_SEC;
384 }
385
386 static void exfat_set_entry_type(struct exfat_dentry *ep, unsigned int type)
387 {
388         if (type == TYPE_UNUSED) {
389                 ep->type = EXFAT_UNUSED;
390         } else if (type == TYPE_DELETED) {
391                 ep->type &= EXFAT_DELETE;
392         } else if (type == TYPE_STREAM) {
393                 ep->type = EXFAT_STREAM;
394         } else if (type == TYPE_EXTEND) {
395                 ep->type = EXFAT_NAME;
396         } else if (type == TYPE_BITMAP) {
397                 ep->type = EXFAT_BITMAP;
398         } else if (type == TYPE_UPCASE) {
399                 ep->type = EXFAT_UPCASE;
400         } else if (type == TYPE_VOLUME) {
401                 ep->type = EXFAT_VOLUME;
402         } else if (type == TYPE_DIR) {
403                 ep->type = EXFAT_FILE;
404                 ep->dentry.file.attr = cpu_to_le16(ATTR_SUBDIR);
405         } else if (type == TYPE_FILE) {
406                 ep->type = EXFAT_FILE;
407                 ep->dentry.file.attr = cpu_to_le16(ATTR_ARCHIVE);
408         }
409 }
410
411 static void exfat_init_stream_entry(struct exfat_dentry *ep,
412                 unsigned char flags, unsigned int start_clu,
413                 unsigned long long size)
414 {
415         exfat_set_entry_type(ep, TYPE_STREAM);
416         ep->dentry.stream.flags = flags;
417         ep->dentry.stream.start_clu = cpu_to_le32(start_clu);
418         ep->dentry.stream.valid_size = cpu_to_le64(size);
419         ep->dentry.stream.size = cpu_to_le64(size);
420 }
421
422 static void exfat_init_name_entry(struct exfat_dentry *ep,
423                 unsigned short *uniname)
424 {
425         int i;
426
427         exfat_set_entry_type(ep, TYPE_EXTEND);
428         ep->dentry.name.flags = 0x0;
429
430         for (i = 0; i < EXFAT_FILE_NAME_LEN; i++) {
431                 if (*uniname != 0x0) {
432                         ep->dentry.name.unicode_0_14[i] = cpu_to_le16(*uniname);
433                         uniname++;
434                 } else {
435                         ep->dentry.name.unicode_0_14[i] = 0x0;
436                 }
437         }
438 }
439
440 int exfat_init_dir_entry(struct inode *inode, struct exfat_chain *p_dir,
441                 int entry, unsigned int type, unsigned int start_clu,
442                 unsigned long long size)
443 {
444         struct super_block *sb = inode->i_sb;
445         struct exfat_sb_info *sbi = EXFAT_SB(sb);
446         struct timespec64 ts = current_time(inode);
447         struct exfat_dentry *ep;
448         struct buffer_head *bh;
449
450         /*
451          * We cannot use exfat_get_dentry_set here because file ep is not
452          * initialized yet.
453          */
454         ep = exfat_get_dentry(sb, p_dir, entry, &bh);
455         if (!ep)
456                 return -EIO;
457
458         exfat_set_entry_type(ep, type);
459         exfat_set_entry_time(sbi, &ts,
460                         &ep->dentry.file.create_tz,
461                         &ep->dentry.file.create_time,
462                         &ep->dentry.file.create_date,
463                         &ep->dentry.file.create_time_cs);
464         exfat_set_entry_time(sbi, &ts,
465                         &ep->dentry.file.modify_tz,
466                         &ep->dentry.file.modify_time,
467                         &ep->dentry.file.modify_date,
468                         &ep->dentry.file.modify_time_cs);
469         exfat_set_entry_time(sbi, &ts,
470                         &ep->dentry.file.access_tz,
471                         &ep->dentry.file.access_time,
472                         &ep->dentry.file.access_date,
473                         NULL);
474
475         exfat_update_bh(bh, IS_DIRSYNC(inode));
476         brelse(bh);
477
478         ep = exfat_get_dentry(sb, p_dir, entry + 1, &bh);
479         if (!ep)
480                 return -EIO;
481
482         exfat_init_stream_entry(ep,
483                 (type == TYPE_FILE) ? ALLOC_FAT_CHAIN : ALLOC_NO_FAT_CHAIN,
484                 start_clu, size);
485         exfat_update_bh(bh, IS_DIRSYNC(inode));
486         brelse(bh);
487
488         return 0;
489 }
490
491 int exfat_update_dir_chksum(struct inode *inode, struct exfat_chain *p_dir,
492                 int entry)
493 {
494         struct super_block *sb = inode->i_sb;
495         int ret = 0;
496         int i, num_entries;
497         u16 chksum;
498         struct exfat_dentry *ep, *fep;
499         struct buffer_head *fbh, *bh;
500
501         fep = exfat_get_dentry(sb, p_dir, entry, &fbh);
502         if (!fep)
503                 return -EIO;
504
505         num_entries = fep->dentry.file.num_ext + 1;
506         chksum = exfat_calc_chksum16(fep, DENTRY_SIZE, 0, CS_DIR_ENTRY);
507
508         for (i = 1; i < num_entries; i++) {
509                 ep = exfat_get_dentry(sb, p_dir, entry + i, &bh);
510                 if (!ep) {
511                         ret = -EIO;
512                         goto release_fbh;
513                 }
514                 chksum = exfat_calc_chksum16(ep, DENTRY_SIZE, chksum,
515                                 CS_DEFAULT);
516                 brelse(bh);
517         }
518
519         fep->dentry.file.checksum = cpu_to_le16(chksum);
520         exfat_update_bh(fbh, IS_DIRSYNC(inode));
521 release_fbh:
522         brelse(fbh);
523         return ret;
524 }
525
526 int exfat_init_ext_entry(struct inode *inode, struct exfat_chain *p_dir,
527                 int entry, int num_entries, struct exfat_uni_name *p_uniname)
528 {
529         struct super_block *sb = inode->i_sb;
530         int i;
531         unsigned short *uniname = p_uniname->name;
532         struct exfat_dentry *ep;
533         struct buffer_head *bh;
534         int sync = IS_DIRSYNC(inode);
535
536         ep = exfat_get_dentry(sb, p_dir, entry, &bh);
537         if (!ep)
538                 return -EIO;
539
540         ep->dentry.file.num_ext = (unsigned char)(num_entries - 1);
541         exfat_update_bh(bh, sync);
542         brelse(bh);
543
544         ep = exfat_get_dentry(sb, p_dir, entry + 1, &bh);
545         if (!ep)
546                 return -EIO;
547
548         ep->dentry.stream.name_len = p_uniname->name_len;
549         ep->dentry.stream.name_hash = cpu_to_le16(p_uniname->name_hash);
550         exfat_update_bh(bh, sync);
551         brelse(bh);
552
553         for (i = EXFAT_FIRST_CLUSTER; i < num_entries; i++) {
554                 ep = exfat_get_dentry(sb, p_dir, entry + i, &bh);
555                 if (!ep)
556                         return -EIO;
557
558                 exfat_init_name_entry(ep, uniname);
559                 exfat_update_bh(bh, sync);
560                 brelse(bh);
561                 uniname += EXFAT_FILE_NAME_LEN;
562         }
563
564         exfat_update_dir_chksum(inode, p_dir, entry);
565         return 0;
566 }
567
568 int exfat_remove_entries(struct inode *inode, struct exfat_chain *p_dir,
569                 int entry, int order, int num_entries)
570 {
571         struct super_block *sb = inode->i_sb;
572         int i;
573         struct exfat_dentry *ep;
574         struct buffer_head *bh;
575
576         for (i = order; i < num_entries; i++) {
577                 ep = exfat_get_dentry(sb, p_dir, entry + i, &bh);
578                 if (!ep)
579                         return -EIO;
580
581                 exfat_set_entry_type(ep, TYPE_DELETED);
582                 exfat_update_bh(bh, IS_DIRSYNC(inode));
583                 brelse(bh);
584         }
585
586         return 0;
587 }
588
589 void exfat_update_dir_chksum_with_entry_set(struct exfat_entry_set_cache *es)
590 {
591         int chksum_type = CS_DIR_ENTRY, i;
592         unsigned short chksum = 0;
593         struct exfat_dentry *ep;
594
595         for (i = 0; i < es->num_entries; i++) {
596                 ep = exfat_get_dentry_cached(es, i);
597                 chksum = exfat_calc_chksum16(ep, DENTRY_SIZE, chksum,
598                                              chksum_type);
599                 chksum_type = CS_DEFAULT;
600         }
601         ep = exfat_get_dentry_cached(es, 0);
602         ep->dentry.file.checksum = cpu_to_le16(chksum);
603         es->modified = true;
604 }
605
606 int exfat_free_dentry_set(struct exfat_entry_set_cache *es, int sync)
607 {
608         int i, err = 0;
609
610         if (es->modified)
611                 err = exfat_update_bhs(es->bh, es->num_bh, sync);
612
613         for (i = 0; i < es->num_bh; i++)
614                 if (err)
615                         bforget(es->bh[i]);
616                 else
617                         brelse(es->bh[i]);
618         kfree(es);
619         return err;
620 }
621
622 static int exfat_walk_fat_chain(struct super_block *sb,
623                 struct exfat_chain *p_dir, unsigned int byte_offset,
624                 unsigned int *clu)
625 {
626         struct exfat_sb_info *sbi = EXFAT_SB(sb);
627         unsigned int clu_offset;
628         unsigned int cur_clu;
629
630         clu_offset = EXFAT_B_TO_CLU(byte_offset, sbi);
631         cur_clu = p_dir->dir;
632
633         if (p_dir->flags == ALLOC_NO_FAT_CHAIN) {
634                 cur_clu += clu_offset;
635         } else {
636                 while (clu_offset > 0) {
637                         if (exfat_get_next_cluster(sb, &cur_clu))
638                                 return -EIO;
639                         if (cur_clu == EXFAT_EOF_CLUSTER) {
640                                 exfat_fs_error(sb,
641                                         "invalid dentry access beyond EOF (clu : %u, eidx : %d)",
642                                         p_dir->dir,
643                                         EXFAT_B_TO_DEN(byte_offset));
644                                 return -EIO;
645                         }
646                         clu_offset--;
647                 }
648         }
649
650         *clu = cur_clu;
651         return 0;
652 }
653
654 static int exfat_find_location(struct super_block *sb, struct exfat_chain *p_dir,
655                                int entry, sector_t *sector, int *offset)
656 {
657         int ret;
658         unsigned int off, clu = 0;
659         struct exfat_sb_info *sbi = EXFAT_SB(sb);
660
661         off = EXFAT_DEN_TO_B(entry);
662
663         ret = exfat_walk_fat_chain(sb, p_dir, off, &clu);
664         if (ret)
665                 return ret;
666
667         /* byte offset in cluster */
668         off = EXFAT_CLU_OFFSET(off, sbi);
669
670         /* byte offset in sector    */
671         *offset = EXFAT_BLK_OFFSET(off, sb);
672
673         /* sector offset in cluster */
674         *sector = EXFAT_B_TO_BLK(off, sb);
675         *sector += exfat_cluster_to_sector(sbi, clu);
676         return 0;
677 }
678
679 #define EXFAT_MAX_RA_SIZE     (128*1024)
680 static int exfat_dir_readahead(struct super_block *sb, sector_t sec)
681 {
682         struct exfat_sb_info *sbi = EXFAT_SB(sb);
683         struct buffer_head *bh;
684         unsigned int max_ra_count = EXFAT_MAX_RA_SIZE >> sb->s_blocksize_bits;
685         unsigned int page_ra_count = PAGE_SIZE >> sb->s_blocksize_bits;
686         unsigned int adj_ra_count = max(sbi->sect_per_clus, page_ra_count);
687         unsigned int ra_count = min(adj_ra_count, max_ra_count);
688
689         /* Read-ahead is not required */
690         if (sbi->sect_per_clus == 1)
691                 return 0;
692
693         if (sec < sbi->data_start_sector) {
694                 exfat_err(sb, "requested sector is invalid(sect:%llu, root:%llu)",
695                           (unsigned long long)sec, sbi->data_start_sector);
696                 return -EIO;
697         }
698
699         /* Not sector aligned with ra_count, resize ra_count to page size */
700         if ((sec - sbi->data_start_sector) & (ra_count - 1))
701                 ra_count = page_ra_count;
702
703         bh = sb_find_get_block(sb, sec);
704         if (!bh || !buffer_uptodate(bh)) {
705                 unsigned int i;
706
707                 for (i = 0; i < ra_count; i++)
708                         sb_breadahead(sb, (sector_t)(sec + i));
709         }
710         brelse(bh);
711         return 0;
712 }
713
714 struct exfat_dentry *exfat_get_dentry(struct super_block *sb,
715                 struct exfat_chain *p_dir, int entry, struct buffer_head **bh)
716 {
717         unsigned int dentries_per_page = EXFAT_B_TO_DEN(PAGE_SIZE);
718         int off;
719         sector_t sec;
720
721         if (p_dir->dir == DIR_DELETED) {
722                 exfat_err(sb, "abnormal access to deleted dentry");
723                 return NULL;
724         }
725
726         if (exfat_find_location(sb, p_dir, entry, &sec, &off))
727                 return NULL;
728
729         if (p_dir->dir != EXFAT_FREE_CLUSTER &&
730                         !(entry & (dentries_per_page - 1)))
731                 exfat_dir_readahead(sb, sec);
732
733         *bh = sb_bread(sb, sec);
734         if (!*bh)
735                 return NULL;
736
737         return (struct exfat_dentry *)((*bh)->b_data + off);
738 }
739
740 enum exfat_validate_dentry_mode {
741         ES_MODE_STARTED,
742         ES_MODE_GET_FILE_ENTRY,
743         ES_MODE_GET_STRM_ENTRY,
744         ES_MODE_GET_NAME_ENTRY,
745         ES_MODE_GET_CRITICAL_SEC_ENTRY,
746 };
747
748 static bool exfat_validate_entry(unsigned int type,
749                 enum exfat_validate_dentry_mode *mode)
750 {
751         if (type == TYPE_UNUSED || type == TYPE_DELETED)
752                 return false;
753
754         switch (*mode) {
755         case ES_MODE_STARTED:
756                 if  (type != TYPE_FILE && type != TYPE_DIR)
757                         return false;
758                 *mode = ES_MODE_GET_FILE_ENTRY;
759                 return true;
760         case ES_MODE_GET_FILE_ENTRY:
761                 if (type != TYPE_STREAM)
762                         return false;
763                 *mode = ES_MODE_GET_STRM_ENTRY;
764                 return true;
765         case ES_MODE_GET_STRM_ENTRY:
766                 if (type != TYPE_EXTEND)
767                         return false;
768                 *mode = ES_MODE_GET_NAME_ENTRY;
769                 return true;
770         case ES_MODE_GET_NAME_ENTRY:
771                 if (type == TYPE_STREAM)
772                         return false;
773                 if (type != TYPE_EXTEND) {
774                         if (!(type & TYPE_CRITICAL_SEC))
775                                 return false;
776                         *mode = ES_MODE_GET_CRITICAL_SEC_ENTRY;
777                 }
778                 return true;
779         case ES_MODE_GET_CRITICAL_SEC_ENTRY:
780                 if (type == TYPE_EXTEND || type == TYPE_STREAM)
781                         return false;
782                 if ((type & TYPE_CRITICAL_SEC) != TYPE_CRITICAL_SEC)
783                         return false;
784                 return true;
785         default:
786                 WARN_ON_ONCE(1);
787                 return false;
788         }
789 }
790
791 struct exfat_dentry *exfat_get_dentry_cached(
792         struct exfat_entry_set_cache *es, int num)
793 {
794         int off = es->start_off + num * DENTRY_SIZE;
795         struct buffer_head *bh = es->bh[EXFAT_B_TO_BLK(off, es->sb)];
796         char *p = bh->b_data + EXFAT_BLK_OFFSET(off, es->sb);
797
798         return (struct exfat_dentry *)p;
799 }
800
801 /*
802  * Returns a set of dentries for a file or dir.
803  *
804  * Note It provides a direct pointer to bh->data via exfat_get_dentry_cached().
805  * User should call exfat_get_dentry_set() after setting 'modified' to apply
806  * changes made in this entry set to the real device.
807  *
808  * in:
809  *   sb+p_dir+entry: indicates a file/dir
810  *   type:  specifies how many dentries should be included.
811  * return:
812  *   pointer of entry set on success,
813  *   NULL on failure.
814  */
815 struct exfat_entry_set_cache *exfat_get_dentry_set(struct super_block *sb,
816                 struct exfat_chain *p_dir, int entry, unsigned int type)
817 {
818         int ret, i, num_bh;
819         unsigned int off, byte_offset, clu = 0;
820         sector_t sec;
821         struct exfat_sb_info *sbi = EXFAT_SB(sb);
822         struct exfat_entry_set_cache *es;
823         struct exfat_dentry *ep;
824         int num_entries;
825         enum exfat_validate_dentry_mode mode = ES_MODE_STARTED;
826         struct buffer_head *bh;
827
828         if (p_dir->dir == DIR_DELETED) {
829                 exfat_err(sb, "access to deleted dentry");
830                 return NULL;
831         }
832
833         byte_offset = EXFAT_DEN_TO_B(entry);
834         ret = exfat_walk_fat_chain(sb, p_dir, byte_offset, &clu);
835         if (ret)
836                 return NULL;
837
838         es = kzalloc(sizeof(*es), GFP_KERNEL);
839         if (!es)
840                 return NULL;
841         es->sb = sb;
842         es->modified = false;
843
844         /* byte offset in cluster */
845         byte_offset = EXFAT_CLU_OFFSET(byte_offset, sbi);
846
847         /* byte offset in sector */
848         off = EXFAT_BLK_OFFSET(byte_offset, sb);
849         es->start_off = off;
850
851         /* sector offset in cluster */
852         sec = EXFAT_B_TO_BLK(byte_offset, sb);
853         sec += exfat_cluster_to_sector(sbi, clu);
854
855         bh = sb_bread(sb, sec);
856         if (!bh)
857                 goto free_es;
858         es->bh[es->num_bh++] = bh;
859
860         ep = exfat_get_dentry_cached(es, 0);
861         if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
862                 goto free_es;
863
864         num_entries = type == ES_ALL_ENTRIES ?
865                 ep->dentry.file.num_ext + 1 : type;
866         es->num_entries = num_entries;
867
868         num_bh = EXFAT_B_TO_BLK_ROUND_UP(off + num_entries * DENTRY_SIZE, sb);
869         for (i = 1; i < num_bh; i++) {
870                 /* get the next sector */
871                 if (exfat_is_last_sector_in_cluster(sbi, sec)) {
872                         if (p_dir->flags == ALLOC_NO_FAT_CHAIN)
873                                 clu++;
874                         else if (exfat_get_next_cluster(sb, &clu))
875                                 goto free_es;
876                         sec = exfat_cluster_to_sector(sbi, clu);
877                 } else {
878                         sec++;
879                 }
880
881                 bh = sb_bread(sb, sec);
882                 if (!bh)
883                         goto free_es;
884                 es->bh[es->num_bh++] = bh;
885         }
886
887         /* validate cached dentries */
888         for (i = 1; i < num_entries; i++) {
889                 ep = exfat_get_dentry_cached(es, i);
890                 if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
891                         goto free_es;
892         }
893         return es;
894
895 free_es:
896         exfat_free_dentry_set(es, false);
897         return NULL;
898 }
899
900 enum {
901         DIRENT_STEP_FILE,
902         DIRENT_STEP_STRM,
903         DIRENT_STEP_NAME,
904         DIRENT_STEP_SECD,
905 };
906
907 /*
908  * @ei:         inode info of parent directory
909  * @p_dir:      directory structure of parent directory
910  * @num_entries:entry size of p_uniname
911  * @hint_opt:   If p_uniname is found, filled with optimized dir/entry
912  *              for traversing cluster chain.
913  * @return:
914  *   >= 0:      file directory entry position where the name exists
915  *   -ENOENT:   entry with the name does not exist
916  *   -EIO:      I/O error
917  */
918 int exfat_find_dir_entry(struct super_block *sb, struct exfat_inode_info *ei,
919                 struct exfat_chain *p_dir, struct exfat_uni_name *p_uniname,
920                 int num_entries, unsigned int type, struct exfat_hint *hint_opt)
921 {
922         int i, rewind = 0, dentry = 0, end_eidx = 0, num_ext = 0, len;
923         int order, step, name_len = 0;
924         int dentries_per_clu, num_empty = 0;
925         unsigned int entry_type;
926         unsigned short *uniname = NULL;
927         struct exfat_chain clu;
928         struct exfat_hint *hint_stat = &ei->hint_stat;
929         struct exfat_hint_femp candi_empty;
930         struct exfat_sb_info *sbi = EXFAT_SB(sb);
931
932         dentries_per_clu = sbi->dentries_per_clu;
933
934         exfat_chain_dup(&clu, p_dir);
935
936         if (hint_stat->eidx) {
937                 clu.dir = hint_stat->clu;
938                 dentry = hint_stat->eidx;
939                 end_eidx = dentry;
940         }
941
942         candi_empty.eidx = EXFAT_HINT_NONE;
943 rewind:
944         order = 0;
945         step = DIRENT_STEP_FILE;
946         while (clu.dir != EXFAT_EOF_CLUSTER) {
947                 i = dentry & (dentries_per_clu - 1);
948                 for (; i < dentries_per_clu; i++, dentry++) {
949                         struct exfat_dentry *ep;
950                         struct buffer_head *bh;
951
952                         if (rewind && dentry == end_eidx)
953                                 goto not_found;
954
955                         ep = exfat_get_dentry(sb, &clu, i, &bh);
956                         if (!ep)
957                                 return -EIO;
958
959                         entry_type = exfat_get_entry_type(ep);
960
961                         if (entry_type == TYPE_UNUSED ||
962                             entry_type == TYPE_DELETED) {
963                                 step = DIRENT_STEP_FILE;
964
965                                 num_empty++;
966                                 if (candi_empty.eidx == EXFAT_HINT_NONE &&
967                                                 num_empty == 1) {
968                                         exfat_chain_set(&candi_empty.cur,
969                                                 clu.dir, clu.size, clu.flags);
970                                 }
971
972                                 if (candi_empty.eidx == EXFAT_HINT_NONE &&
973                                                 num_empty >= num_entries) {
974                                         candi_empty.eidx =
975                                                 dentry - (num_empty - 1);
976                                         WARN_ON(candi_empty.eidx < 0);
977                                         candi_empty.count = num_empty;
978
979                                         if (ei->hint_femp.eidx ==
980                                                         EXFAT_HINT_NONE ||
981                                                 candi_empty.eidx <=
982                                                          ei->hint_femp.eidx)
983                                                 ei->hint_femp = candi_empty;
984                                 }
985
986                                 brelse(bh);
987                                 if (entry_type == TYPE_UNUSED)
988                                         goto not_found;
989                                 continue;
990                         }
991
992                         num_empty = 0;
993                         candi_empty.eidx = EXFAT_HINT_NONE;
994
995                         if (entry_type == TYPE_FILE || entry_type == TYPE_DIR) {
996                                 step = DIRENT_STEP_FILE;
997                                 hint_opt->clu = clu.dir;
998                                 hint_opt->eidx = i;
999                                 if (type == TYPE_ALL || type == entry_type) {
1000                                         num_ext = ep->dentry.file.num_ext;
1001                                         step = DIRENT_STEP_STRM;
1002                                 }
1003                                 brelse(bh);
1004                                 continue;
1005                         }
1006
1007                         if (entry_type == TYPE_STREAM) {
1008                                 u16 name_hash;
1009
1010                                 if (step != DIRENT_STEP_STRM) {
1011                                         step = DIRENT_STEP_FILE;
1012                                         brelse(bh);
1013                                         continue;
1014                                 }
1015                                 step = DIRENT_STEP_FILE;
1016                                 name_hash = le16_to_cpu(
1017                                                 ep->dentry.stream.name_hash);
1018                                 if (p_uniname->name_hash == name_hash &&
1019                                     p_uniname->name_len ==
1020                                                 ep->dentry.stream.name_len) {
1021                                         step = DIRENT_STEP_NAME;
1022                                         order = 1;
1023                                         name_len = 0;
1024                                 }
1025                                 brelse(bh);
1026                                 continue;
1027                         }
1028
1029                         brelse(bh);
1030                         if (entry_type == TYPE_EXTEND) {
1031                                 unsigned short entry_uniname[16], unichar;
1032
1033                                 if (step != DIRENT_STEP_NAME) {
1034                                         step = DIRENT_STEP_FILE;
1035                                         continue;
1036                                 }
1037
1038                                 if (++order == 2)
1039                                         uniname = p_uniname->name;
1040                                 else
1041                                         uniname += EXFAT_FILE_NAME_LEN;
1042
1043                                 len = exfat_extract_uni_name(ep, entry_uniname);
1044                                 name_len += len;
1045
1046                                 unichar = *(uniname+len);
1047                                 *(uniname+len) = 0x0;
1048
1049                                 if (exfat_uniname_ncmp(sb, uniname,
1050                                         entry_uniname, len)) {
1051                                         step = DIRENT_STEP_FILE;
1052                                 } else if (p_uniname->name_len == name_len) {
1053                                         if (order == num_ext)
1054                                                 goto found;
1055                                         step = DIRENT_STEP_SECD;
1056                                 }
1057
1058                                 *(uniname+len) = unichar;
1059                                 continue;
1060                         }
1061
1062                         if (entry_type &
1063                                         (TYPE_CRITICAL_SEC | TYPE_BENIGN_SEC)) {
1064                                 if (step == DIRENT_STEP_SECD) {
1065                                         if (++order == num_ext)
1066                                                 goto found;
1067                                         continue;
1068                                 }
1069                         }
1070                         step = DIRENT_STEP_FILE;
1071                 }
1072
1073                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1074                         if (--clu.size > 0)
1075                                 clu.dir++;
1076                         else
1077                                 clu.dir = EXFAT_EOF_CLUSTER;
1078                 } else {
1079                         if (exfat_get_next_cluster(sb, &clu.dir))
1080                                 return -EIO;
1081                 }
1082         }
1083
1084 not_found:
1085         /*
1086          * We started at not 0 index,so we should try to find target
1087          * from 0 index to the index we started at.
1088          */
1089         if (!rewind && end_eidx) {
1090                 rewind = 1;
1091                 dentry = 0;
1092                 clu.dir = p_dir->dir;
1093                 /* reset empty hint */
1094                 num_empty = 0;
1095                 candi_empty.eidx = EXFAT_HINT_NONE;
1096                 goto rewind;
1097         }
1098
1099         /* initialized hint_stat */
1100         hint_stat->clu = p_dir->dir;
1101         hint_stat->eidx = 0;
1102         return -ENOENT;
1103
1104 found:
1105         /* next dentry we'll find is out of this cluster */
1106         if (!((dentry + 1) & (dentries_per_clu - 1))) {
1107                 int ret = 0;
1108
1109                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1110                         if (--clu.size > 0)
1111                                 clu.dir++;
1112                         else
1113                                 clu.dir = EXFAT_EOF_CLUSTER;
1114                 } else {
1115                         ret = exfat_get_next_cluster(sb, &clu.dir);
1116                 }
1117
1118                 if (ret || clu.dir == EXFAT_EOF_CLUSTER) {
1119                         /* just initialized hint_stat */
1120                         hint_stat->clu = p_dir->dir;
1121                         hint_stat->eidx = 0;
1122                         return (dentry - num_ext);
1123                 }
1124         }
1125
1126         hint_stat->clu = clu.dir;
1127         hint_stat->eidx = dentry + 1;
1128         return dentry - num_ext;
1129 }
1130
1131 int exfat_count_ext_entries(struct super_block *sb, struct exfat_chain *p_dir,
1132                 int entry, struct exfat_dentry *ep)
1133 {
1134         int i, count = 0;
1135         unsigned int type;
1136         struct exfat_dentry *ext_ep;
1137         struct buffer_head *bh;
1138
1139         for (i = 0, entry++; i < ep->dentry.file.num_ext; i++, entry++) {
1140                 ext_ep = exfat_get_dentry(sb, p_dir, entry, &bh);
1141                 if (!ext_ep)
1142                         return -EIO;
1143
1144                 type = exfat_get_entry_type(ext_ep);
1145                 brelse(bh);
1146                 if (type == TYPE_EXTEND || type == TYPE_STREAM)
1147                         count++;
1148                 else
1149                         break;
1150         }
1151         return count;
1152 }
1153
1154 int exfat_count_dir_entries(struct super_block *sb, struct exfat_chain *p_dir)
1155 {
1156         int i, count = 0;
1157         int dentries_per_clu;
1158         unsigned int entry_type;
1159         struct exfat_chain clu;
1160         struct exfat_dentry *ep;
1161         struct exfat_sb_info *sbi = EXFAT_SB(sb);
1162         struct buffer_head *bh;
1163
1164         dentries_per_clu = sbi->dentries_per_clu;
1165
1166         exfat_chain_dup(&clu, p_dir);
1167
1168         while (clu.dir != EXFAT_EOF_CLUSTER) {
1169                 for (i = 0; i < dentries_per_clu; i++) {
1170                         ep = exfat_get_dentry(sb, &clu, i, &bh);
1171                         if (!ep)
1172                                 return -EIO;
1173                         entry_type = exfat_get_entry_type(ep);
1174                         brelse(bh);
1175
1176                         if (entry_type == TYPE_UNUSED)
1177                                 return count;
1178                         if (entry_type != TYPE_DIR)
1179                                 continue;
1180                         count++;
1181                 }
1182
1183                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1184                         if (--clu.size > 0)
1185                                 clu.dir++;
1186                         else
1187                                 clu.dir = EXFAT_EOF_CLUSTER;
1188                 } else {
1189                         if (exfat_get_next_cluster(sb, &(clu.dir)))
1190                                 return -EIO;
1191                 }
1192         }
1193
1194         return count;
1195 }