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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 
205         pr_debug("%s(\"%pd\")\n", __func__, dentry);
206 
207         affs_lock_dir(dir);
208         bh = affs_find_entry(dir, dentry);
209         affs_unlock_dir(dir);
210         if (IS_ERR(bh))
211                 return ERR_CAST(bh);
212         if (bh) {
213                 u32 ino = bh->b_blocknr;
214 
215                 /* store the real header ino in d_fsdata for faster lookups */
216                 dentry->d_fsdata = (void *)(long)ino;
217                 switch (be32_to_cpu(AFFS_TAIL(sb, bh)->stype)) {
218                 //link to dirs disabled
219                 //case ST_LINKDIR:
220                 case ST_LINKFILE:
221                         ino = be32_to_cpu(AFFS_TAIL(sb, bh)->original);
222                 }
223                 affs_brelse(bh);
224                 inode = affs_iget(sb, ino);
225                 if (IS_ERR(inode))
226                         return ERR_CAST(inode);
227         }
228         d_add(dentry, inode);
229         return NULL;
230 }
231 
232 int
233 affs_unlink(struct inode *dir, struct dentry *dentry)
234 {
235         pr_debug("%s(dir=%lu, %lu \"%pd\")\n", __func__, dir->i_ino,
236                  d_inode(dentry)->i_ino, dentry);
237 
238         return affs_remove_header(dentry);
239 }
240 
241 int
242 affs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl)
243 {
244         struct super_block *sb = dir->i_sb;
245         struct inode    *inode;
246         int              error;
247 
248         pr_debug("%s(%lu,\"%pd\",0%ho)\n",
249                  __func__, dir->i_ino, dentry, mode);
250 
251         inode = affs_new_inode(dir);
252         if (!inode)
253                 return -ENOSPC;
254 
255         inode->i_mode = mode;
256         affs_mode_to_prot(inode);
257         mark_inode_dirty(inode);
258 
259         inode->i_op = &affs_file_inode_operations;
260         inode->i_fop = &affs_file_operations;
261         inode->i_mapping->a_ops = affs_test_opt(AFFS_SB(sb)->s_flags, SF_OFS) ?
262                                   &affs_aops_ofs : &affs_aops;
263         error = affs_add_entry(dir, inode, dentry, ST_FILE);
264         if (error) {
265                 clear_nlink(inode);
266                 iput(inode);
267                 return error;
268         }
269         return 0;
270 }
271 
272 int
273 affs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
274 {
275         struct inode            *inode;
276         int                      error;
277 
278         pr_debug("%s(%lu,\"%pd\",0%ho)\n",
279                  __func__, dir->i_ino, dentry, mode);
280 
281         inode = affs_new_inode(dir);
282         if (!inode)
283                 return -ENOSPC;
284 
285         inode->i_mode = S_IFDIR | mode;
286         affs_mode_to_prot(inode);
287 
288         inode->i_op = &affs_dir_inode_operations;
289         inode->i_fop = &affs_dir_operations;
290 
291         error = affs_add_entry(dir, inode, dentry, ST_USERDIR);
292         if (error) {
293                 clear_nlink(inode);
294                 mark_inode_dirty(inode);
295                 iput(inode);
296                 return error;
297         }
298         return 0;
299 }
300 
301 int
302 affs_rmdir(struct inode *dir, struct dentry *dentry)
303 {
304         pr_debug("%s(dir=%lu, %lu \"%pd\")\n", __func__, dir->i_ino,
305                  d_inode(dentry)->i_ino, dentry);
306 
307         return affs_remove_header(dentry);
308 }
309 
310 int
311 affs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
312 {
313         struct super_block      *sb = dir->i_sb;
314         struct buffer_head      *bh;
315         struct inode            *inode;
316         char                    *p;
317         int                      i, maxlen, error;
318         char                     c, lc;
319 
320         pr_debug("%s(%lu,\"%pd\" -> \"%s\")\n",
321                  __func__, dir->i_ino, dentry, symname);
322 
323         maxlen = AFFS_SB(sb)->s_hashsize * sizeof(u32) - 1;
324         inode  = affs_new_inode(dir);
325         if (!inode)
326                 return -ENOSPC;
327 
328         inode->i_op = &affs_symlink_inode_operations;
329         inode_nohighmem(inode);
330         inode->i_data.a_ops = &affs_symlink_aops;
331         inode->i_mode = S_IFLNK | 0777;
332         affs_mode_to_prot(inode);
333 
334         error = -EIO;
335         bh = affs_bread(sb, inode->i_ino);
336         if (!bh)
337                 goto err;
338         i  = 0;
339         p  = (char *)AFFS_HEAD(bh)->table;
340         lc = '/';
341         if (*symname == '/') {
342                 struct affs_sb_info *sbi = AFFS_SB(sb);
343                 while (*symname == '/')
344                         symname++;
345                 spin_lock(&sbi->symlink_lock);
346                 while (sbi->s_volume[i])        /* Cannot overflow */
347                         *p++ = sbi->s_volume[i++];
348                 spin_unlock(&sbi->symlink_lock);
349         }
350         while (i < maxlen && (c = *symname++)) {
351                 if (c == '.' && lc == '/' && *symname == '.' && symname[1] == '/') {
352                         *p++ = '/';
353                         i++;
354                         symname += 2;
355                         lc = '/';
356                 } else if (c == '.' && lc == '/' && *symname == '/') {
357                         symname++;
358                         lc = '/';
359                 } else {
360                         *p++ = c;
361                         lc   = c;
362                         i++;
363                 }
364                 if (lc == '/')
365                         while (*symname == '/')
366                                 symname++;
367         }
368         *p = 0;
369         inode->i_size = i + 1;
370         mark_buffer_dirty_inode(bh, inode);
371         affs_brelse(bh);
372         mark_inode_dirty(inode);
373 
374         error = affs_add_entry(dir, inode, dentry, ST_SOFTLINK);
375         if (error)
376                 goto err;
377 
378         return 0;
379 
380 err:
381         clear_nlink(inode);
382         mark_inode_dirty(inode);
383         iput(inode);
384         return error;
385 }
386 
387 int
388 affs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
389 {
390         struct inode *inode = d_inode(old_dentry);
391 
392         pr_debug("%s(%lu, %lu, \"%pd\")\n", __func__, inode->i_ino, dir->i_ino,
393                  dentry);
394 
395         return affs_add_entry(dir, inode, dentry, ST_LINKFILE);
396 }
397 
398 static int
399 affs_rename(struct inode *old_dir, struct dentry *old_dentry,
400             struct inode *new_dir, struct dentry *new_dentry)
401 {
402         struct super_block *sb = old_dir->i_sb;
403         struct buffer_head *bh = NULL;
404         int retval;
405 
406         retval = affs_check_name(new_dentry->d_name.name,
407                                  new_dentry->d_name.len,
408                                  affs_nofilenametruncate(old_dentry));
409 
410         if (retval)
411                 return retval;
412 
413         /* Unlink destination if it already exists */
414         if (d_really_is_positive(new_dentry)) {
415                 retval = affs_remove_header(new_dentry);
416                 if (retval)
417                         return retval;
418         }
419 
420         bh = affs_bread(sb, d_inode(old_dentry)->i_ino);
421         if (!bh)
422                 return -EIO;
423 
424         /* Remove header from its parent directory. */
425         affs_lock_dir(old_dir);
426         retval = affs_remove_hash(old_dir, bh);
427         affs_unlock_dir(old_dir);
428         if (retval)
429                 goto done;
430 
431         /* And insert it into the new directory with the new name. */
432         affs_copy_name(AFFS_TAIL(sb, bh)->name, new_dentry);
433         affs_fix_checksum(sb, bh);
434         affs_lock_dir(new_dir);
435         retval = affs_insert_hash(new_dir, bh);
436         affs_unlock_dir(new_dir);
437         /* TODO: move it back to old_dir, if error? */
438 
439 done:
440         mark_buffer_dirty_inode(bh, retval ? old_dir : new_dir);
441         affs_brelse(bh);
442         return retval;
443 }
444 
445 static int
446 affs_xrename(struct inode *old_dir, struct dentry *old_dentry,
447              struct inode *new_dir, struct dentry *new_dentry)
448 {
449 
450         struct super_block *sb = old_dir->i_sb;
451         struct buffer_head *bh_old = NULL;
452         struct buffer_head *bh_new = NULL;
453         int retval;
454 
455         bh_old = affs_bread(sb, d_inode(old_dentry)->i_ino);
456         if (!bh_old)
457                 return -EIO;
458 
459         bh_new = affs_bread(sb, d_inode(new_dentry)->i_ino);
460         if (!bh_new)
461                 return -EIO;
462 
463         /* Remove old header from its parent directory. */
464         affs_lock_dir(old_dir);
465         retval = affs_remove_hash(old_dir, bh_old);
466         affs_unlock_dir(old_dir);
467         if (retval)
468                 goto done;
469 
470         /* Remove new header from its parent directory. */
471         affs_lock_dir(new_dir);
472         retval = affs_remove_hash(new_dir, bh_new);
473         affs_unlock_dir(new_dir);
474         if (retval)
475                 goto done;
476 
477         /* Insert old into the new directory with the new name. */
478         affs_copy_name(AFFS_TAIL(sb, bh_old)->name, new_dentry);
479         affs_fix_checksum(sb, bh_old);
480         affs_lock_dir(new_dir);
481         retval = affs_insert_hash(new_dir, bh_old);
482         affs_unlock_dir(new_dir);
483 
484         /* Insert new into the old directory with the old name. */
485         affs_copy_name(AFFS_TAIL(sb, bh_new)->name, old_dentry);
486         affs_fix_checksum(sb, bh_new);
487         affs_lock_dir(old_dir);
488         retval = affs_insert_hash(old_dir, bh_new);
489         affs_unlock_dir(old_dir);
490 done:
491         mark_buffer_dirty_inode(bh_old, new_dir);
492         mark_buffer_dirty_inode(bh_new, old_dir);
493         affs_brelse(bh_old);
494         affs_brelse(bh_new);
495         return retval;
496 }
497 
498 int affs_rename2(struct inode *old_dir, struct dentry *old_dentry,
499                         struct inode *new_dir, struct dentry *new_dentry,
500                         unsigned int flags)
501 {
502 
503         if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE))
504                 return -EINVAL;
505 
506         pr_debug("%s(old=%lu,\"%pd\" to new=%lu,\"%pd\")\n", __func__,
507                  old_dir->i_ino, old_dentry, new_dir->i_ino, new_dentry);
508 
509         if (flags & RENAME_EXCHANGE)
510                 return affs_xrename(old_dir, old_dentry, new_dir, new_dentry);
511 
512         return affs_rename(old_dir, old_dentry, new_dir, new_dentry);
513 }
514 
515 static struct dentry *affs_get_parent(struct dentry *child)
516 {
517         struct inode *parent;
518         struct buffer_head *bh;
519 
520         bh = affs_bread(child->d_sb, d_inode(child)->i_ino);
521         if (!bh)
522                 return ERR_PTR(-EIO);
523 
524         parent = affs_iget(child->d_sb,
525                            be32_to_cpu(AFFS_TAIL(child->d_sb, bh)->parent));
526         brelse(bh);
527         if (IS_ERR(parent))
528                 return ERR_CAST(parent);
529 
530         return d_obtain_alias(parent);
531 }
532 
533 static struct inode *affs_nfs_get_inode(struct super_block *sb, u64 ino,
534                                         u32 generation)
535 {
536         struct inode *inode;
537 
538         if (!affs_validblock(sb, ino))
539                 return ERR_PTR(-ESTALE);
540 
541         inode = affs_iget(sb, ino);
542         if (IS_ERR(inode))
543                 return ERR_CAST(inode);
544 
545         return inode;
546 }
547 
548 static struct dentry *affs_fh_to_dentry(struct super_block *sb, struct fid *fid,
549                                         int fh_len, int fh_type)
550 {
551         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
552                                     affs_nfs_get_inode);
553 }
554 
555 static struct dentry *affs_fh_to_parent(struct super_block *sb, struct fid *fid,
556                                         int fh_len, int fh_type)
557 {
558         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
559                                     affs_nfs_get_inode);
560 }
561 
562 const struct export_operations affs_export_ops = {
563         .fh_to_dentry = affs_fh_to_dentry,
564         .fh_to_parent = affs_fh_to_parent,
565         .get_parent = affs_get_parent,
566 };
567 
568 const struct dentry_operations affs_dentry_operations = {
569         .d_hash         = affs_hash_dentry,
570         .d_compare      = affs_compare_dentry,
571 };
572 
573 const struct dentry_operations affs_intl_dentry_operations = {
574         .d_hash         = affs_intl_hash_dentry,
575         .d_compare      = affs_intl_compare_dentry,
576 };
577 

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