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Linux/fs/nilfs2/namei.c

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  1 // SPDX-License-Identifier: GPL-2.0+
  2 /*
  3  * namei.c - NILFS pathname lookup operations.
  4  *
  5  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
  6  *
  7  * Modified for NILFS by Amagai Yoshiji and Ryusuke Konishi.
  8  */
  9 /*
 10  *  linux/fs/ext2/namei.c
 11  *
 12  * Copyright (C) 1992, 1993, 1994, 1995
 13  * Remy Card (card@masi.ibp.fr)
 14  * Laboratoire MASI - Institut Blaise Pascal
 15  * Universite Pierre et Marie Curie (Paris VI)
 16  *
 17  *  from
 18  *
 19  *  linux/fs/minix/namei.c
 20  *
 21  *  Copyright (C) 1991, 1992  Linus Torvalds
 22  *
 23  *  Big-endian to little-endian byte-swapping/bitmaps by
 24  *        David S. Miller (davem@caip.rutgers.edu), 1995
 25  */
 26 
 27 #include <linux/pagemap.h>
 28 #include "nilfs.h"
 29 #include "export.h"
 30 
 31 #define NILFS_FID_SIZE_NON_CONNECTABLE \
 32         (offsetof(struct nilfs_fid, parent_gen) / 4)
 33 #define NILFS_FID_SIZE_CONNECTABLE      (sizeof(struct nilfs_fid) / 4)
 34 
 35 static inline int nilfs_add_nondir(struct dentry *dentry, struct inode *inode)
 36 {
 37         int err = nilfs_add_link(dentry, inode);
 38 
 39         if (!err) {
 40                 d_instantiate_new(dentry, inode);
 41                 return 0;
 42         }
 43         inode_dec_link_count(inode);
 44         unlock_new_inode(inode);
 45         iput(inode);
 46         return err;
 47 }
 48 
 49 /*
 50  * Methods themselves.
 51  */
 52 
 53 static struct dentry *
 54 nilfs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
 55 {
 56         struct inode *inode;
 57         ino_t ino;
 58 
 59         if (dentry->d_name.len > NILFS_NAME_LEN)
 60                 return ERR_PTR(-ENAMETOOLONG);
 61 
 62         ino = nilfs_inode_by_name(dir, &dentry->d_name);
 63         inode = ino ? nilfs_iget(dir->i_sb, NILFS_I(dir)->i_root, ino) : NULL;
 64         return d_splice_alias(inode, dentry);
 65 }
 66 
 67 /*
 68  * By the time this is called, we already have created
 69  * the directory cache entry for the new file, but it
 70  * is so far negative - it has no inode.
 71  *
 72  * If the create succeeds, we fill in the inode information
 73  * with d_instantiate().
 74  */
 75 static int nilfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 76                         bool excl)
 77 {
 78         struct inode *inode;
 79         struct nilfs_transaction_info ti;
 80         int err;
 81 
 82         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 83         if (err)
 84                 return err;
 85         inode = nilfs_new_inode(dir, mode);
 86         err = PTR_ERR(inode);
 87         if (!IS_ERR(inode)) {
 88                 inode->i_op = &nilfs_file_inode_operations;
 89                 inode->i_fop = &nilfs_file_operations;
 90                 inode->i_mapping->a_ops = &nilfs_aops;
 91                 nilfs_mark_inode_dirty(inode);
 92                 err = nilfs_add_nondir(dentry, inode);
 93         }
 94         if (!err)
 95                 err = nilfs_transaction_commit(dir->i_sb);
 96         else
 97                 nilfs_transaction_abort(dir->i_sb);
 98 
 99         return err;
100 }
101 
102 static int
103 nilfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t rdev)
104 {
105         struct inode *inode;
106         struct nilfs_transaction_info ti;
107         int err;
108 
109         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
110         if (err)
111                 return err;
112         inode = nilfs_new_inode(dir, mode);
113         err = PTR_ERR(inode);
114         if (!IS_ERR(inode)) {
115                 init_special_inode(inode, inode->i_mode, rdev);
116                 nilfs_mark_inode_dirty(inode);
117                 err = nilfs_add_nondir(dentry, inode);
118         }
119         if (!err)
120                 err = nilfs_transaction_commit(dir->i_sb);
121         else
122                 nilfs_transaction_abort(dir->i_sb);
123 
124         return err;
125 }
126 
127 static int nilfs_symlink(struct inode *dir, struct dentry *dentry,
128                          const char *symname)
129 {
130         struct nilfs_transaction_info ti;
131         struct super_block *sb = dir->i_sb;
132         unsigned int l = strlen(symname) + 1;
133         struct inode *inode;
134         int err;
135 
136         if (l > sb->s_blocksize)
137                 return -ENAMETOOLONG;
138 
139         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
140         if (err)
141                 return err;
142 
143         inode = nilfs_new_inode(dir, S_IFLNK | 0777);
144         err = PTR_ERR(inode);
145         if (IS_ERR(inode))
146                 goto out;
147 
148         /* slow symlink */
149         inode->i_op = &nilfs_symlink_inode_operations;
150         inode_nohighmem(inode);
151         inode->i_mapping->a_ops = &nilfs_aops;
152         err = page_symlink(inode, symname, l);
153         if (err)
154                 goto out_fail;
155 
156         /* mark_inode_dirty(inode); */
157         /* page_symlink() do this */
158 
159         err = nilfs_add_nondir(dentry, inode);
160 out:
161         if (!err)
162                 err = nilfs_transaction_commit(dir->i_sb);
163         else
164                 nilfs_transaction_abort(dir->i_sb);
165 
166         return err;
167 
168 out_fail:
169         drop_nlink(inode);
170         nilfs_mark_inode_dirty(inode);
171         unlock_new_inode(inode);
172         iput(inode);
173         goto out;
174 }
175 
176 static int nilfs_link(struct dentry *old_dentry, struct inode *dir,
177                       struct dentry *dentry)
178 {
179         struct inode *inode = d_inode(old_dentry);
180         struct nilfs_transaction_info ti;
181         int err;
182 
183         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
184         if (err)
185                 return err;
186 
187         inode->i_ctime = current_time(inode);
188         inode_inc_link_count(inode);
189         ihold(inode);
190 
191         err = nilfs_add_link(dentry, inode);
192         if (!err) {
193                 d_instantiate(dentry, inode);
194                 err = nilfs_transaction_commit(dir->i_sb);
195         } else {
196                 inode_dec_link_count(inode);
197                 iput(inode);
198                 nilfs_transaction_abort(dir->i_sb);
199         }
200 
201         return err;
202 }
203 
204 static int nilfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
205 {
206         struct inode *inode;
207         struct nilfs_transaction_info ti;
208         int err;
209 
210         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
211         if (err)
212                 return err;
213 
214         inc_nlink(dir);
215 
216         inode = nilfs_new_inode(dir, S_IFDIR | mode);
217         err = PTR_ERR(inode);
218         if (IS_ERR(inode))
219                 goto out_dir;
220 
221         inode->i_op = &nilfs_dir_inode_operations;
222         inode->i_fop = &nilfs_dir_operations;
223         inode->i_mapping->a_ops = &nilfs_aops;
224 
225         inc_nlink(inode);
226 
227         err = nilfs_make_empty(inode, dir);
228         if (err)
229                 goto out_fail;
230 
231         err = nilfs_add_link(dentry, inode);
232         if (err)
233                 goto out_fail;
234 
235         nilfs_mark_inode_dirty(inode);
236         d_instantiate_new(dentry, inode);
237 out:
238         if (!err)
239                 err = nilfs_transaction_commit(dir->i_sb);
240         else
241                 nilfs_transaction_abort(dir->i_sb);
242 
243         return err;
244 
245 out_fail:
246         drop_nlink(inode);
247         drop_nlink(inode);
248         nilfs_mark_inode_dirty(inode);
249         unlock_new_inode(inode);
250         iput(inode);
251 out_dir:
252         drop_nlink(dir);
253         nilfs_mark_inode_dirty(dir);
254         goto out;
255 }
256 
257 static int nilfs_do_unlink(struct inode *dir, struct dentry *dentry)
258 {
259         struct inode *inode;
260         struct nilfs_dir_entry *de;
261         struct page *page;
262         int err;
263 
264         err = -ENOENT;
265         de = nilfs_find_entry(dir, &dentry->d_name, &page);
266         if (!de)
267                 goto out;
268 
269         inode = d_inode(dentry);
270         err = -EIO;
271         if (le64_to_cpu(de->inode) != inode->i_ino)
272                 goto out;
273 
274         if (!inode->i_nlink) {
275                 nilfs_msg(inode->i_sb, KERN_WARNING,
276                           "deleting nonexistent file (ino=%lu), %d",
277                           inode->i_ino, inode->i_nlink);
278                 set_nlink(inode, 1);
279         }
280         err = nilfs_delete_entry(de, page);
281         if (err)
282                 goto out;
283 
284         inode->i_ctime = dir->i_ctime;
285         drop_nlink(inode);
286         err = 0;
287 out:
288         return err;
289 }
290 
291 static int nilfs_unlink(struct inode *dir, struct dentry *dentry)
292 {
293         struct nilfs_transaction_info ti;
294         int err;
295 
296         err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
297         if (err)
298                 return err;
299 
300         err = nilfs_do_unlink(dir, dentry);
301 
302         if (!err) {
303                 nilfs_mark_inode_dirty(dir);
304                 nilfs_mark_inode_dirty(d_inode(dentry));
305                 err = nilfs_transaction_commit(dir->i_sb);
306         } else
307                 nilfs_transaction_abort(dir->i_sb);
308 
309         return err;
310 }
311 
312 static int nilfs_rmdir(struct inode *dir, struct dentry *dentry)
313 {
314         struct inode *inode = d_inode(dentry);
315         struct nilfs_transaction_info ti;
316         int err;
317 
318         err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
319         if (err)
320                 return err;
321 
322         err = -ENOTEMPTY;
323         if (nilfs_empty_dir(inode)) {
324                 err = nilfs_do_unlink(dir, dentry);
325                 if (!err) {
326                         inode->i_size = 0;
327                         drop_nlink(inode);
328                         nilfs_mark_inode_dirty(inode);
329                         drop_nlink(dir);
330                         nilfs_mark_inode_dirty(dir);
331                 }
332         }
333         if (!err)
334                 err = nilfs_transaction_commit(dir->i_sb);
335         else
336                 nilfs_transaction_abort(dir->i_sb);
337 
338         return err;
339 }
340 
341 static int nilfs_rename(struct inode *old_dir, struct dentry *old_dentry,
342                         struct inode *new_dir,  struct dentry *new_dentry,
343                         unsigned int flags)
344 {
345         struct inode *old_inode = d_inode(old_dentry);
346         struct inode *new_inode = d_inode(new_dentry);
347         struct page *dir_page = NULL;
348         struct nilfs_dir_entry *dir_de = NULL;
349         struct page *old_page;
350         struct nilfs_dir_entry *old_de;
351         struct nilfs_transaction_info ti;
352         int err;
353 
354         if (flags & ~RENAME_NOREPLACE)
355                 return -EINVAL;
356 
357         err = nilfs_transaction_begin(old_dir->i_sb, &ti, 1);
358         if (unlikely(err))
359                 return err;
360 
361         err = -ENOENT;
362         old_de = nilfs_find_entry(old_dir, &old_dentry->d_name, &old_page);
363         if (!old_de)
364                 goto out;
365 
366         if (S_ISDIR(old_inode->i_mode)) {
367                 err = -EIO;
368                 dir_de = nilfs_dotdot(old_inode, &dir_page);
369                 if (!dir_de)
370                         goto out_old;
371         }
372 
373         if (new_inode) {
374                 struct page *new_page;
375                 struct nilfs_dir_entry *new_de;
376 
377                 err = -ENOTEMPTY;
378                 if (dir_de && !nilfs_empty_dir(new_inode))
379                         goto out_dir;
380 
381                 err = -ENOENT;
382                 new_de = nilfs_find_entry(new_dir, &new_dentry->d_name, &new_page);
383                 if (!new_de)
384                         goto out_dir;
385                 nilfs_set_link(new_dir, new_de, new_page, old_inode);
386                 nilfs_mark_inode_dirty(new_dir);
387                 new_inode->i_ctime = current_time(new_inode);
388                 if (dir_de)
389                         drop_nlink(new_inode);
390                 drop_nlink(new_inode);
391                 nilfs_mark_inode_dirty(new_inode);
392         } else {
393                 err = nilfs_add_link(new_dentry, old_inode);
394                 if (err)
395                         goto out_dir;
396                 if (dir_de) {
397                         inc_nlink(new_dir);
398                         nilfs_mark_inode_dirty(new_dir);
399                 }
400         }
401 
402         /*
403          * Like most other Unix systems, set the ctime for inodes on a
404          * rename.
405          */
406         old_inode->i_ctime = current_time(old_inode);
407 
408         nilfs_delete_entry(old_de, old_page);
409 
410         if (dir_de) {
411                 nilfs_set_link(old_inode, dir_de, dir_page, new_dir);
412                 drop_nlink(old_dir);
413         }
414         nilfs_mark_inode_dirty(old_dir);
415         nilfs_mark_inode_dirty(old_inode);
416 
417         err = nilfs_transaction_commit(old_dir->i_sb);
418         return err;
419 
420 out_dir:
421         if (dir_de) {
422                 kunmap(dir_page);
423                 put_page(dir_page);
424         }
425 out_old:
426         kunmap(old_page);
427         put_page(old_page);
428 out:
429         nilfs_transaction_abort(old_dir->i_sb);
430         return err;
431 }
432 
433 /*
434  * Export operations
435  */
436 static struct dentry *nilfs_get_parent(struct dentry *child)
437 {
438         unsigned long ino;
439         struct inode *inode;
440         struct qstr dotdot = QSTR_INIT("..", 2);
441         struct nilfs_root *root;
442 
443         ino = nilfs_inode_by_name(d_inode(child), &dotdot);
444         if (!ino)
445                 return ERR_PTR(-ENOENT);
446 
447         root = NILFS_I(d_inode(child))->i_root;
448 
449         inode = nilfs_iget(child->d_sb, root, ino);
450         if (IS_ERR(inode))
451                 return ERR_CAST(inode);
452 
453         return d_obtain_alias(inode);
454 }
455 
456 static struct dentry *nilfs_get_dentry(struct super_block *sb, u64 cno,
457                                        u64 ino, u32 gen)
458 {
459         struct nilfs_root *root;
460         struct inode *inode;
461 
462         if (ino < NILFS_FIRST_INO(sb) && ino != NILFS_ROOT_INO)
463                 return ERR_PTR(-ESTALE);
464 
465         root = nilfs_lookup_root(sb->s_fs_info, cno);
466         if (!root)
467                 return ERR_PTR(-ESTALE);
468 
469         inode = nilfs_iget(sb, root, ino);
470         nilfs_put_root(root);
471 
472         if (IS_ERR(inode))
473                 return ERR_CAST(inode);
474         if (gen && inode->i_generation != gen) {
475                 iput(inode);
476                 return ERR_PTR(-ESTALE);
477         }
478         return d_obtain_alias(inode);
479 }
480 
481 static struct dentry *nilfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
482                                          int fh_len, int fh_type)
483 {
484         struct nilfs_fid *fid = (struct nilfs_fid *)fh;
485 
486         if (fh_len < NILFS_FID_SIZE_NON_CONNECTABLE ||
487             (fh_type != FILEID_NILFS_WITH_PARENT &&
488              fh_type != FILEID_NILFS_WITHOUT_PARENT))
489                 return NULL;
490 
491         return nilfs_get_dentry(sb, fid->cno, fid->ino, fid->gen);
492 }
493 
494 static struct dentry *nilfs_fh_to_parent(struct super_block *sb, struct fid *fh,
495                                          int fh_len, int fh_type)
496 {
497         struct nilfs_fid *fid = (struct nilfs_fid *)fh;
498 
499         if (fh_len < NILFS_FID_SIZE_CONNECTABLE ||
500             fh_type != FILEID_NILFS_WITH_PARENT)
501                 return NULL;
502 
503         return nilfs_get_dentry(sb, fid->cno, fid->parent_ino, fid->parent_gen);
504 }
505 
506 static int nilfs_encode_fh(struct inode *inode, __u32 *fh, int *lenp,
507                            struct inode *parent)
508 {
509         struct nilfs_fid *fid = (struct nilfs_fid *)fh;
510         struct nilfs_root *root = NILFS_I(inode)->i_root;
511         int type;
512 
513         if (parent && *lenp < NILFS_FID_SIZE_CONNECTABLE) {
514                 *lenp = NILFS_FID_SIZE_CONNECTABLE;
515                 return FILEID_INVALID;
516         }
517         if (*lenp < NILFS_FID_SIZE_NON_CONNECTABLE) {
518                 *lenp = NILFS_FID_SIZE_NON_CONNECTABLE;
519                 return FILEID_INVALID;
520         }
521 
522         fid->cno = root->cno;
523         fid->ino = inode->i_ino;
524         fid->gen = inode->i_generation;
525 
526         if (parent) {
527                 fid->parent_ino = parent->i_ino;
528                 fid->parent_gen = parent->i_generation;
529                 type = FILEID_NILFS_WITH_PARENT;
530                 *lenp = NILFS_FID_SIZE_CONNECTABLE;
531         } else {
532                 type = FILEID_NILFS_WITHOUT_PARENT;
533                 *lenp = NILFS_FID_SIZE_NON_CONNECTABLE;
534         }
535 
536         return type;
537 }
538 
539 const struct inode_operations nilfs_dir_inode_operations = {
540         .create         = nilfs_create,
541         .lookup         = nilfs_lookup,
542         .link           = nilfs_link,
543         .unlink         = nilfs_unlink,
544         .symlink        = nilfs_symlink,
545         .mkdir          = nilfs_mkdir,
546         .rmdir          = nilfs_rmdir,
547         .mknod          = nilfs_mknod,
548         .rename         = nilfs_rename,
549         .setattr        = nilfs_setattr,
550         .permission     = nilfs_permission,
551         .fiemap         = nilfs_fiemap,
552 };
553 
554 const struct inode_operations nilfs_special_inode_operations = {
555         .setattr        = nilfs_setattr,
556         .permission     = nilfs_permission,
557 };
558 
559 const struct inode_operations nilfs_symlink_inode_operations = {
560         .get_link       = page_get_link,
561         .permission     = nilfs_permission,
562 };
563 
564 const struct export_operations nilfs_export_ops = {
565         .encode_fh = nilfs_encode_fh,
566         .fh_to_dentry = nilfs_fh_to_dentry,
567         .fh_to_parent = nilfs_fh_to_parent,
568         .get_parent = nilfs_get_parent,
569 };
570 

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