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Linux/fs/affs/namei.c

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  1 // SPDX-License-Identifier: GPL-2.0
  2 /*
  3  *  linux/fs/affs/namei.c
  4  *
  5  *  (c) 1996  Hans-Joachim Widmaier - Rewritten
  6  *
  7  *  (C) 1993  Ray Burr - Modified for Amiga FFS filesystem.
  8  *
  9  *  (C) 1991  Linus Torvalds - minix filesystem
 10  */
 11 
 12 #include "affs.h"
 13 #include <linux/exportfs.h>
 14 
 15 typedef int (*toupper_t)(int);
 16 
 17 /* Simple toupper() for DOS\1 */
 18 
 19 static int
 20 affs_toupper(int ch)
 21 {
 22         return ch >= 'a' && ch <= 'z' ? ch -= ('a' - 'A') : ch;
 23 }
 24 
 25 /* International toupper() for DOS\3 ("international") */
 26 
 27 static int
 28 affs_intl_toupper(int ch)
 29 {
 30         return (ch >= 'a' && ch <= 'z') || (ch >= 0xE0
 31                 && ch <= 0xFE && ch != 0xF7) ?
 32                 ch - ('a' - 'A') : ch;
 33 }
 34 
 35 static inline toupper_t
 36 affs_get_toupper(struct super_block *sb)
 37 {
 38         return affs_test_opt(AFFS_SB(sb)->s_flags, SF_INTL) ?
 39                affs_intl_toupper : affs_toupper;
 40 }
 41 
 42 /*
 43  * Note: the dentry argument is the parent dentry.
 44  */
 45 static inline int
 46 __affs_hash_dentry(const struct dentry *dentry, struct qstr *qstr, toupper_t toupper, bool notruncate)
 47 {
 48         const u8 *name = qstr->name;
 49         unsigned long hash;
 50         int retval;
 51         u32 len;
 52 
 53         retval = affs_check_name(qstr->name, qstr->len, notruncate);
 54         if (retval)
 55                 return retval;
 56 
 57         hash = init_name_hash(dentry);
 58         len = min(qstr->len, AFFSNAMEMAX);
 59         for (; len > 0; name++, len--)
 60                 hash = partial_name_hash(toupper(*name), hash);
 61         qstr->hash = end_name_hash(hash);
 62 
 63         return 0;
 64 }
 65 
 66 static int
 67 affs_hash_dentry(const struct dentry *dentry, struct qstr *qstr)
 68 {
 69         return __affs_hash_dentry(dentry, qstr, affs_toupper,
 70                                   affs_nofilenametruncate(dentry));
 71 
 72 }
 73 
 74 static int
 75 affs_intl_hash_dentry(const struct dentry *dentry, struct qstr *qstr)
 76 {
 77         return __affs_hash_dentry(dentry, qstr, affs_intl_toupper,
 78                                   affs_nofilenametruncate(dentry));
 79 
 80 }
 81 
 82 static inline int __affs_compare_dentry(unsigned int len,
 83                 const char *str, const struct qstr *name, toupper_t toupper,
 84                 bool notruncate)
 85 {
 86         const u8 *aname = str;
 87         const u8 *bname = name->name;
 88 
 89         /*
 90          * 'str' is the name of an already existing dentry, so the name
 91          * must be valid. 'name' must be validated first.
 92          */
 93 
 94         if (affs_check_name(name->name, name->len, notruncate))
 95                 return 1;
 96 
 97         /*
 98          * If the names are longer than the allowed 30 chars,
 99          * the excess is ignored, so their length may differ.
100          */
101         if (len >= AFFSNAMEMAX) {
102                 if (name->len < AFFSNAMEMAX)
103                         return 1;
104                 len = AFFSNAMEMAX;
105         } else if (len != name->len)
106                 return 1;
107 
108         for (; len > 0; len--)
109                 if (toupper(*aname++) != toupper(*bname++))
110                         return 1;
111 
112         return 0;
113 }
114 
115 static int
116 affs_compare_dentry(const struct dentry *dentry,
117                 unsigned int len, const char *str, const struct qstr *name)
118 {
119 
120         return __affs_compare_dentry(len, str, name, affs_toupper,
121                                      affs_nofilenametruncate(dentry));
122 }
123 
124 static int
125 affs_intl_compare_dentry(const struct dentry *dentry,
126                 unsigned int len, const char *str, const struct qstr *name)
127 {
128         return __affs_compare_dentry(len, str, name, affs_intl_toupper,
129                                      affs_nofilenametruncate(dentry));
130 
131 }
132 
133 /*
134  * NOTE! unlike strncmp, affs_match returns 1 for success, 0 for failure.
135  */
136 
137 static inline int
138 affs_match(struct dentry *dentry, const u8 *name2, toupper_t toupper)
139 {
140         const u8 *name = dentry->d_name.name;
141         int len = dentry->d_name.len;
142 
143         if (len >= AFFSNAMEMAX) {
144                 if (*name2 < AFFSNAMEMAX)
145                         return 0;
146                 len = AFFSNAMEMAX;
147         } else if (len != *name2)
148                 return 0;
149 
150         for (name2++; len > 0; len--)
151                 if (toupper(*name++) != toupper(*name2++))
152                         return 0;
153         return 1;
154 }
155 
156 int
157 affs_hash_name(struct super_block *sb, const u8 *name, unsigned int len)
158 {
159         toupper_t toupper = affs_get_toupper(sb);
160         u32 hash;
161 
162         hash = len = min(len, AFFSNAMEMAX);
163         for (; len > 0; len--)
164                 hash = (hash * 13 + toupper(*name++)) & 0x7ff;
165 
166         return hash % AFFS_SB(sb)->s_hashsize;
167 }
168 
169 static struct buffer_head *
170 affs_find_entry(struct inode *dir, struct dentry *dentry)
171 {
172         struct super_block *sb = dir->i_sb;
173         struct buffer_head *bh;
174         toupper_t toupper = affs_get_toupper(sb);
175         u32 key;
176 
177         pr_debug("%s(\"%pd\")\n", __func__, dentry);
178 
179         bh = affs_bread(sb, dir->i_ino);
180         if (!bh)
181                 return ERR_PTR(-EIO);
182 
183         key = be32_to_cpu(AFFS_HEAD(bh)->table[affs_hash_name(sb, dentry->d_name.name, dentry->d_name.len)]);
184 
185         for (;;) {
186                 affs_brelse(bh);
187                 if (key == 0)
188                         return NULL;
189                 bh = affs_bread(sb, key);
190                 if (!bh)
191                         return ERR_PTR(-EIO);
192                 if (affs_match(dentry, AFFS_TAIL(sb, bh)->name, toupper))
193                         return bh;
194                 key = be32_to_cpu(AFFS_TAIL(sb, bh)->hash_chain);
195         }
196 }
197 
198 struct dentry *
199 affs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
200 {
201         struct super_block *sb = dir->i_sb;
202         struct buffer_head *bh;
203         struct inode *inode = NULL;
204         struct dentry *res;
205 
206         pr_debug("%s(\"%pd\")\n", __func__, dentry);
207 
208         affs_lock_dir(dir);
209         bh = affs_find_entry(dir, dentry);
210         if (IS_ERR(bh)) {
211                 affs_unlock_dir(dir);
212                 return ERR_CAST(bh);
213         }
214         if (bh) {
215                 u32 ino = bh->b_blocknr;
216 
217                 /* store the real header ino in d_fsdata for faster lookups */
218                 dentry->d_fsdata = (void *)(long)ino;
219                 switch (be32_to_cpu(AFFS_TAIL(sb, bh)->stype)) {
220                 //link to dirs disabled
221                 //case ST_LINKDIR:
222                 case ST_LINKFILE:
223                         ino = be32_to_cpu(AFFS_TAIL(sb, bh)->original);
224                 }
225                 affs_brelse(bh);
226                 inode = affs_iget(sb, ino);
227         }
228         res = d_splice_alias(inode, dentry);
229         if (!IS_ERR_OR_NULL(res))
230                 res->d_fsdata = dentry->d_fsdata;
231         affs_unlock_dir(dir);
232         return res;
233 }
234 
235 int
236 affs_unlink(struct inode *dir, struct dentry *dentry)
237 {
238         pr_debug("%s(dir=%lu, %lu \"%pd\")\n", __func__, dir->i_ino,
239                  d_inode(dentry)->i_ino, dentry);
240 
241         return affs_remove_header(dentry);
242 }
243 
244 int
245 affs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl)
246 {
247         struct super_block *sb = dir->i_sb;
248         struct inode    *inode;
249         int              error;
250 
251         pr_debug("%s(%lu,\"%pd\",0%ho)\n",
252                  __func__, dir->i_ino, dentry, mode);
253 
254         inode = affs_new_inode(dir);
255         if (!inode)
256                 return -ENOSPC;
257 
258         inode->i_mode = mode;
259         affs_mode_to_prot(inode);
260         mark_inode_dirty(inode);
261 
262         inode->i_op = &affs_file_inode_operations;
263         inode->i_fop = &affs_file_operations;
264         inode->i_mapping->a_ops = affs_test_opt(AFFS_SB(sb)->s_flags, SF_OFS) ?
265                                   &affs_aops_ofs : &affs_aops;
266         error = affs_add_entry(dir, inode, dentry, ST_FILE);
267         if (error) {
268                 clear_nlink(inode);
269                 iput(inode);
270                 return error;
271         }
272         return 0;
273 }
274 
275 int
276 affs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
277 {
278         struct inode            *inode;
279         int                      error;
280 
281         pr_debug("%s(%lu,\"%pd\",0%ho)\n",
282                  __func__, dir->i_ino, dentry, mode);
283 
284         inode = affs_new_inode(dir);
285         if (!inode)
286                 return -ENOSPC;
287 
288         inode->i_mode = S_IFDIR | mode;
289         affs_mode_to_prot(inode);
290 
291         inode->i_op = &affs_dir_inode_operations;
292         inode->i_fop = &affs_dir_operations;
293 
294         error = affs_add_entry(dir, inode, dentry, ST_USERDIR);
295         if (error) {
296                 clear_nlink(inode);
297                 mark_inode_dirty(inode);
298                 iput(inode);
299                 return error;
300         }
301         return 0;
302 }
303 
304 int
305 affs_rmdir(struct inode *dir, struct dentry *dentry)
306 {
307         pr_debug("%s(dir=%lu, %lu \"%pd\")\n", __func__, dir->i_ino,
308                  d_inode(dentry)->i_ino, dentry);
309 
310         return affs_remove_header(dentry);
311 }
312 
313 int
314 affs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
315 {
316         struct super_block      *sb = dir->i_sb;
317         struct buffer_head      *bh;
318         struct inode            *inode;
319         char                    *p;
320         int                      i, maxlen, error;
321         char                     c, lc;
322 
323         pr_debug("%s(%lu,\"%pd\" -> \"%s\")\n",
324                  __func__, dir->i_ino, dentry, symname);
325 
326         maxlen = AFFS_SB(sb)->s_hashsize * sizeof(u32) - 1;
327         inode  = affs_new_inode(dir);
328         if (!inode)
329                 return -ENOSPC;
330 
331         inode->i_op = &affs_symlink_inode_operations;
332         inode_nohighmem(inode);
333         inode->i_data.a_ops = &affs_symlink_aops;
334         inode->i_mode = S_IFLNK | 0777;
335         affs_mode_to_prot(inode);
336 
337         error = -EIO;
338         bh = affs_bread(sb, inode->i_ino);
339         if (!bh)
340                 goto err;
341         i  = 0;
342         p  = (char *)AFFS_HEAD(bh)->table;
343         lc = '/';
344         if (*symname == '/') {
345                 struct affs_sb_info *sbi = AFFS_SB(sb);
346                 while (*symname == '/')
347                         symname++;
348                 spin_lock(&sbi->symlink_lock);
349                 while (sbi->s_volume[i])        /* Cannot overflow */
350                         *p++ = sbi->s_volume[i++];
351                 spin_unlock(&sbi->symlink_lock);
352         }
353         while (i < maxlen && (c = *symname++)) {
354                 if (c == '.' && lc == '/' && *symname == '.' && symname[1] == '/') {
355                         *p++ = '/';
356                         i++;
357                         symname += 2;
358                         lc = '/';
359                 } else if (c == '.' && lc == '/' && *symname == '/') {
360                         symname++;
361                         lc = '/';
362                 } else {
363                         *p++ = c;
364                         lc   = c;
365                         i++;
366                 }
367                 if (lc == '/')
368                         while (*symname == '/')
369                                 symname++;
370         }
371         *p = 0;
372         inode->i_size = i + 1;
373         mark_buffer_dirty_inode(bh, inode);
374         affs_brelse(bh);
375         mark_inode_dirty(inode);
376 
377         error = affs_add_entry(dir, inode, dentry, ST_SOFTLINK);
378         if (error)
379                 goto err;
380 
381         return 0;
382 
383 err:
384         clear_nlink(inode);
385         mark_inode_dirty(inode);
386         iput(inode);
387         return error;
388 }
389 
390 int
391 affs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
392 {
393         struct inode *inode = d_inode(old_dentry);
394 
395         pr_debug("%s(%lu, %lu, \"%pd\")\n", __func__, inode->i_ino, dir->i_ino,
396                  dentry);
397 
398         return affs_add_entry(dir, inode, dentry, ST_LINKFILE);
399 }
400 
401 static int
402 affs_rename(struct inode *old_dir, struct dentry *old_dentry,
403             struct inode *new_dir, struct dentry *new_dentry)
404 {
405         struct super_block *sb = old_dir->i_sb;
406         struct buffer_head *bh = NULL;
407         int retval;
408 
409         retval = affs_check_name(new_dentry->d_name.name,
410                                  new_dentry->d_name.len,
411                                  affs_nofilenametruncate(old_dentry));
412 
413         if (retval)
414                 return retval;
415 
416         /* Unlink destination if it already exists */
417         if (d_really_is_positive(new_dentry)) {
418                 retval = affs_remove_header(new_dentry);
419                 if (retval)
420                         return retval;
421         }
422 
423         bh = affs_bread(sb, d_inode(old_dentry)->i_ino);
424         if (!bh)
425                 return -EIO;
426 
427         /* Remove header from its parent directory. */
428         affs_lock_dir(old_dir);
429         retval = affs_remove_hash(old_dir, bh);
430         affs_unlock_dir(old_dir);
431         if (retval)
432                 goto done;
433 
434         /* And insert it into the new directory with the new name. */
435         affs_copy_name(AFFS_TAIL(sb, bh)->name, new_dentry);
436         affs_fix_checksum(sb, bh);
437         affs_lock_dir(new_dir);
438         retval = affs_insert_hash(new_dir, bh);
439         affs_unlock_dir(new_dir);
440         /* TODO: move it back to old_dir, if error? */
441 
442 done:
443         mark_buffer_dirty_inode(bh, retval ? old_dir : new_dir);
444         affs_brelse(bh);
445         return retval;
446 }
447 
448 static int
449 affs_xrename(struct inode *old_dir, struct dentry *old_dentry,
450              struct inode *new_dir, struct dentry *new_dentry)
451 {
452 
453         struct super_block *sb = old_dir->i_sb;
454         struct buffer_head *bh_old = NULL;
455         struct buffer_head *bh_new = NULL;
456         int retval;
457 
458         bh_old = affs_bread(sb, d_inode(old_dentry)->i_ino);
459         if (!bh_old)
460                 return -EIO;
461 
462         bh_new = affs_bread(sb, d_inode(new_dentry)->i_ino);
463         if (!bh_new)
464                 return -EIO;
465 
466         /* Remove old header from its parent directory. */
467         affs_lock_dir(old_dir);
468         retval = affs_remove_hash(old_dir, bh_old);
469         affs_unlock_dir(old_dir);
470         if (retval)
471                 goto done;
472 
473         /* Remove new header from its parent directory. */
474         affs_lock_dir(new_dir);
475         retval = affs_remove_hash(new_dir, bh_new);
476         affs_unlock_dir(new_dir);
477         if (retval)
478                 goto done;
479 
480         /* Insert old into the new directory with the new name. */
481         affs_copy_name(AFFS_TAIL(sb, bh_old)->name, new_dentry);
482         affs_fix_checksum(sb, bh_old);
483         affs_lock_dir(new_dir);
484         retval = affs_insert_hash(new_dir, bh_old);
485         affs_unlock_dir(new_dir);
486 
487         /* Insert new into the old directory with the old name. */
488         affs_copy_name(AFFS_TAIL(sb, bh_new)->name, old_dentry);
489         affs_fix_checksum(sb, bh_new);
490         affs_lock_dir(old_dir);
491         retval = affs_insert_hash(old_dir, bh_new);
492         affs_unlock_dir(old_dir);
493 done:
494         mark_buffer_dirty_inode(bh_old, new_dir);
495         mark_buffer_dirty_inode(bh_new, old_dir);
496         affs_brelse(bh_old);
497         affs_brelse(bh_new);
498         return retval;
499 }
500 
501 int affs_rename2(struct inode *old_dir, struct dentry *old_dentry,
502                         struct inode *new_dir, struct dentry *new_dentry,
503                         unsigned int flags)
504 {
505 
506         if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE))
507                 return -EINVAL;
508 
509         pr_debug("%s(old=%lu,\"%pd\" to new=%lu,\"%pd\")\n", __func__,
510                  old_dir->i_ino, old_dentry, new_dir->i_ino, new_dentry);
511 
512         if (flags & RENAME_EXCHANGE)
513                 return affs_xrename(old_dir, old_dentry, new_dir, new_dentry);
514 
515         return affs_rename(old_dir, old_dentry, new_dir, new_dentry);
516 }
517 
518 static struct dentry *affs_get_parent(struct dentry *child)
519 {
520         struct inode *parent;
521         struct buffer_head *bh;
522 
523         bh = affs_bread(child->d_sb, d_inode(child)->i_ino);
524         if (!bh)
525                 return ERR_PTR(-EIO);
526 
527         parent = affs_iget(child->d_sb,
528                            be32_to_cpu(AFFS_TAIL(child->d_sb, bh)->parent));
529         brelse(bh);
530         if (IS_ERR(parent))
531                 return ERR_CAST(parent);
532 
533         return d_obtain_alias(parent);
534 }
535 
536 static struct inode *affs_nfs_get_inode(struct super_block *sb, u64 ino,
537                                         u32 generation)
538 {
539         struct inode *inode;
540 
541         if (!affs_validblock(sb, ino))
542                 return ERR_PTR(-ESTALE);
543 
544         inode = affs_iget(sb, ino);
545         if (IS_ERR(inode))
546                 return ERR_CAST(inode);
547 
548         return inode;
549 }
550 
551 static struct dentry *affs_fh_to_dentry(struct super_block *sb, struct fid *fid,
552                                         int fh_len, int fh_type)
553 {
554         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
555                                     affs_nfs_get_inode);
556 }
557 
558 static struct dentry *affs_fh_to_parent(struct super_block *sb, struct fid *fid,
559                                         int fh_len, int fh_type)
560 {
561         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
562                                     affs_nfs_get_inode);
563 }
564 
565 const struct export_operations affs_export_ops = {
566         .fh_to_dentry = affs_fh_to_dentry,
567         .fh_to_parent = affs_fh_to_parent,
568         .get_parent = affs_get_parent,
569 };
570 
571 const struct dentry_operations affs_dentry_operations = {
572         .d_hash         = affs_hash_dentry,
573         .d_compare      = affs_compare_dentry,
574 };
575 
576 const struct dentry_operations affs_intl_dentry_operations = {
577         .d_hash         = affs_intl_hash_dentry,
578         .d_compare      = affs_intl_compare_dentry,
579 };
580 

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