blob: ad1432a2a62ee85eeef7bfaea49d142c1161af08 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/fs/ext2/namei.c
3 *
4 * Rewrite to pagecache. Almost all code had been changed, so blame me
5 * if the things go wrong. Please, send bug reports to
6 * viro@parcelfarce.linux.theplanet.co.uk
7 *
8 * Stuff here is basically a glue between the VFS and generic UNIXish
9 * filesystem that keeps everything in pagecache. All knowledge of the
10 * directory layout is in fs/ext2/dir.c - it turned out to be easily separatable
11 * and it's easier to debug that way. In principle we might want to
12 * generalize that a bit and turn it into a library. Or not.
13 *
14 * The only non-static object here is ext2_dir_inode_operations.
15 *
16 * TODO: get rid of kmap() use, add readahead.
17 *
18 * Copyright (C) 1992, 1993, 1994, 1995
19 * Remy Card (card@masi.ibp.fr)
20 * Laboratoire MASI - Institut Blaise Pascal
21 * Universite Pierre et Marie Curie (Paris VI)
22 *
23 * from
24 *
25 * linux/fs/minix/namei.c
26 *
27 * Copyright (C) 1991, 1992 Linus Torvalds
28 *
29 * Big-endian to little-endian byte-swapping/bitmaps by
30 * David S. Miller (davem@caip.rutgers.edu), 1995
31 */
32
33#include <linux/pagemap.h>
34#include "ext2.h"
35#include "xattr.h"
36#include "acl.h"
Carsten Otte6d791252005-06-23 22:05:26 -070037#include "xip.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070038
39/*
40 * Couple of helper functions - make the code slightly cleaner.
41 */
42
43static inline void ext2_inc_count(struct inode *inode)
44{
45 inode->i_nlink++;
46 mark_inode_dirty(inode);
47}
48
49static inline void ext2_dec_count(struct inode *inode)
50{
51 inode->i_nlink--;
52 mark_inode_dirty(inode);
53}
54
55static inline int ext2_add_nondir(struct dentry *dentry, struct inode *inode)
56{
57 int err = ext2_add_link(dentry, inode);
58 if (!err) {
59 d_instantiate(dentry, inode);
60 return 0;
61 }
62 ext2_dec_count(inode);
63 iput(inode);
64 return err;
65}
66
67/*
68 * Methods themselves.
69 */
70
71static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry, struct nameidata *nd)
72{
73 struct inode * inode;
74 ino_t ino;
75
76 if (dentry->d_name.len > EXT2_NAME_LEN)
77 return ERR_PTR(-ENAMETOOLONG);
78
79 ino = ext2_inode_by_name(dir, dentry);
80 inode = NULL;
81 if (ino) {
82 inode = iget(dir->i_sb, ino);
83 if (!inode)
84 return ERR_PTR(-EACCES);
85 }
Pekka Enberg082a05c2006-01-14 13:21:07 -080086 return d_splice_alias(inode, dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -070087}
88
89struct dentry *ext2_get_parent(struct dentry *child)
90{
91 unsigned long ino;
92 struct dentry *parent;
93 struct inode *inode;
94 struct dentry dotdot;
95
96 dotdot.d_name.name = "..";
97 dotdot.d_name.len = 2;
98
99 ino = ext2_inode_by_name(child->d_inode, &dotdot);
100 if (!ino)
101 return ERR_PTR(-ENOENT);
102 inode = iget(child->d_inode->i_sb, ino);
103
104 if (!inode)
105 return ERR_PTR(-EACCES);
106 parent = d_alloc_anon(inode);
107 if (!parent) {
108 iput(inode);
109 parent = ERR_PTR(-ENOMEM);
110 }
111 return parent;
112}
113
114/*
115 * By the time this is called, we already have created
116 * the directory cache entry for the new file, but it
117 * is so far negative - it has no inode.
118 *
119 * If the create succeeds, we fill in the inode information
120 * with d_instantiate().
121 */
122static int ext2_create (struct inode * dir, struct dentry * dentry, int mode, struct nameidata *nd)
123{
124 struct inode * inode = ext2_new_inode (dir, mode);
125 int err = PTR_ERR(inode);
126 if (!IS_ERR(inode)) {
127 inode->i_op = &ext2_file_inode_operations;
Carsten Otte6d791252005-06-23 22:05:26 -0700128 if (ext2_use_xip(inode->i_sb)) {
129 inode->i_mapping->a_ops = &ext2_aops_xip;
130 inode->i_fop = &ext2_xip_file_operations;
131 } else if (test_opt(inode->i_sb, NOBH)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132 inode->i_mapping->a_ops = &ext2_nobh_aops;
Carsten Otte6d791252005-06-23 22:05:26 -0700133 inode->i_fop = &ext2_file_operations;
134 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135 inode->i_mapping->a_ops = &ext2_aops;
Carsten Otte6d791252005-06-23 22:05:26 -0700136 inode->i_fop = &ext2_file_operations;
137 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138 mark_inode_dirty(inode);
139 err = ext2_add_nondir(dentry, inode);
140 }
141 return err;
142}
143
144static int ext2_mknod (struct inode * dir, struct dentry *dentry, int mode, dev_t rdev)
145{
146 struct inode * inode;
147 int err;
148
149 if (!new_valid_dev(rdev))
150 return -EINVAL;
151
152 inode = ext2_new_inode (dir, mode);
153 err = PTR_ERR(inode);
154 if (!IS_ERR(inode)) {
155 init_special_inode(inode, inode->i_mode, rdev);
156#ifdef CONFIG_EXT2_FS_XATTR
157 inode->i_op = &ext2_special_inode_operations;
158#endif
159 mark_inode_dirty(inode);
160 err = ext2_add_nondir(dentry, inode);
161 }
162 return err;
163}
164
165static int ext2_symlink (struct inode * dir, struct dentry * dentry,
166 const char * symname)
167{
168 struct super_block * sb = dir->i_sb;
169 int err = -ENAMETOOLONG;
170 unsigned l = strlen(symname)+1;
171 struct inode * inode;
172
173 if (l > sb->s_blocksize)
174 goto out;
175
176 inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO);
177 err = PTR_ERR(inode);
178 if (IS_ERR(inode))
179 goto out;
180
181 if (l > sizeof (EXT2_I(inode)->i_data)) {
182 /* slow symlink */
183 inode->i_op = &ext2_symlink_inode_operations;
184 if (test_opt(inode->i_sb, NOBH))
185 inode->i_mapping->a_ops = &ext2_nobh_aops;
186 else
187 inode->i_mapping->a_ops = &ext2_aops;
188 err = page_symlink(inode, symname, l);
189 if (err)
190 goto out_fail;
191 } else {
192 /* fast symlink */
193 inode->i_op = &ext2_fast_symlink_inode_operations;
194 memcpy((char*)(EXT2_I(inode)->i_data),symname,l);
195 inode->i_size = l-1;
196 }
197 mark_inode_dirty(inode);
198
199 err = ext2_add_nondir(dentry, inode);
200out:
201 return err;
202
203out_fail:
204 ext2_dec_count(inode);
205 iput (inode);
206 goto out;
207}
208
209static int ext2_link (struct dentry * old_dentry, struct inode * dir,
210 struct dentry *dentry)
211{
212 struct inode *inode = old_dentry->d_inode;
213
214 if (inode->i_nlink >= EXT2_LINK_MAX)
215 return -EMLINK;
216
217 inode->i_ctime = CURRENT_TIME_SEC;
218 ext2_inc_count(inode);
219 atomic_inc(&inode->i_count);
220
221 return ext2_add_nondir(dentry, inode);
222}
223
224static int ext2_mkdir(struct inode * dir, struct dentry * dentry, int mode)
225{
226 struct inode * inode;
227 int err = -EMLINK;
228
229 if (dir->i_nlink >= EXT2_LINK_MAX)
230 goto out;
231
232 ext2_inc_count(dir);
233
234 inode = ext2_new_inode (dir, S_IFDIR | mode);
235 err = PTR_ERR(inode);
236 if (IS_ERR(inode))
237 goto out_dir;
238
239 inode->i_op = &ext2_dir_inode_operations;
240 inode->i_fop = &ext2_dir_operations;
241 if (test_opt(inode->i_sb, NOBH))
242 inode->i_mapping->a_ops = &ext2_nobh_aops;
243 else
244 inode->i_mapping->a_ops = &ext2_aops;
245
246 ext2_inc_count(inode);
247
248 err = ext2_make_empty(inode, dir);
249 if (err)
250 goto out_fail;
251
252 err = ext2_add_link(dentry, inode);
253 if (err)
254 goto out_fail;
255
256 d_instantiate(dentry, inode);
257out:
258 return err;
259
260out_fail:
261 ext2_dec_count(inode);
262 ext2_dec_count(inode);
263 iput(inode);
264out_dir:
265 ext2_dec_count(dir);
266 goto out;
267}
268
269static int ext2_unlink(struct inode * dir, struct dentry *dentry)
270{
271 struct inode * inode = dentry->d_inode;
272 struct ext2_dir_entry_2 * de;
273 struct page * page;
274 int err = -ENOENT;
275
276 de = ext2_find_entry (dir, dentry, &page);
277 if (!de)
278 goto out;
279
280 err = ext2_delete_entry (de, page);
281 if (err)
282 goto out;
283
284 inode->i_ctime = dir->i_ctime;
285 ext2_dec_count(inode);
286 err = 0;
287out:
288 return err;
289}
290
291static int ext2_rmdir (struct inode * dir, struct dentry *dentry)
292{
293 struct inode * inode = dentry->d_inode;
294 int err = -ENOTEMPTY;
295
296 if (ext2_empty_dir(inode)) {
297 err = ext2_unlink(dir, dentry);
298 if (!err) {
299 inode->i_size = 0;
300 ext2_dec_count(inode);
301 ext2_dec_count(dir);
302 }
303 }
304 return err;
305}
306
307static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry,
308 struct inode * new_dir, struct dentry * new_dentry )
309{
310 struct inode * old_inode = old_dentry->d_inode;
311 struct inode * new_inode = new_dentry->d_inode;
312 struct page * dir_page = NULL;
313 struct ext2_dir_entry_2 * dir_de = NULL;
314 struct page * old_page;
315 struct ext2_dir_entry_2 * old_de;
316 int err = -ENOENT;
317
318 old_de = ext2_find_entry (old_dir, old_dentry, &old_page);
319 if (!old_de)
320 goto out;
321
322 if (S_ISDIR(old_inode->i_mode)) {
323 err = -EIO;
324 dir_de = ext2_dotdot(old_inode, &dir_page);
325 if (!dir_de)
326 goto out_old;
327 }
328
329 if (new_inode) {
330 struct page *new_page;
331 struct ext2_dir_entry_2 *new_de;
332
333 err = -ENOTEMPTY;
334 if (dir_de && !ext2_empty_dir (new_inode))
335 goto out_dir;
336
337 err = -ENOENT;
338 new_de = ext2_find_entry (new_dir, new_dentry, &new_page);
339 if (!new_de)
340 goto out_dir;
341 ext2_inc_count(old_inode);
342 ext2_set_link(new_dir, new_de, new_page, old_inode);
343 new_inode->i_ctime = CURRENT_TIME_SEC;
344 if (dir_de)
345 new_inode->i_nlink--;
346 ext2_dec_count(new_inode);
347 } else {
348 if (dir_de) {
349 err = -EMLINK;
350 if (new_dir->i_nlink >= EXT2_LINK_MAX)
351 goto out_dir;
352 }
353 ext2_inc_count(old_inode);
354 err = ext2_add_link(new_dentry, old_inode);
355 if (err) {
356 ext2_dec_count(old_inode);
357 goto out_dir;
358 }
359 if (dir_de)
360 ext2_inc_count(new_dir);
361 }
362
363 /*
364 * Like most other Unix systems, set the ctime for inodes on a
365 * rename.
366 * ext2_dec_count() will mark the inode dirty.
367 */
368 old_inode->i_ctime = CURRENT_TIME_SEC;
369
370 ext2_delete_entry (old_de, old_page);
371 ext2_dec_count(old_inode);
372
373 if (dir_de) {
374 ext2_set_link(old_inode, dir_de, dir_page, new_dir);
375 ext2_dec_count(old_dir);
376 }
377 return 0;
378
379
380out_dir:
381 if (dir_de) {
382 kunmap(dir_page);
383 page_cache_release(dir_page);
384 }
385out_old:
386 kunmap(old_page);
387 page_cache_release(old_page);
388out:
389 return err;
390}
391
392struct inode_operations ext2_dir_inode_operations = {
393 .create = ext2_create,
394 .lookup = ext2_lookup,
395 .link = ext2_link,
396 .unlink = ext2_unlink,
397 .symlink = ext2_symlink,
398 .mkdir = ext2_mkdir,
399 .rmdir = ext2_rmdir,
400 .mknod = ext2_mknod,
401 .rename = ext2_rename,
402#ifdef CONFIG_EXT2_FS_XATTR
403 .setxattr = generic_setxattr,
404 .getxattr = generic_getxattr,
405 .listxattr = ext2_listxattr,
406 .removexattr = generic_removexattr,
407#endif
408 .setattr = ext2_setattr,
409 .permission = ext2_permission,
410};
411
412struct inode_operations ext2_special_inode_operations = {
413#ifdef CONFIG_EXT2_FS_XATTR
414 .setxattr = generic_setxattr,
415 .getxattr = generic_getxattr,
416 .listxattr = ext2_listxattr,
417 .removexattr = generic_removexattr,
418#endif
419 .setattr = ext2_setattr,
420 .permission = ext2_permission,
421};