Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
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" | |
37 | ||
38 | /* | |
39 | * Couple of helper functions - make the code slightly cleaner. | |
40 | */ | |
41 | ||
42 | static inline void ext2_inc_count(struct inode *inode) | |
43 | { | |
44 | inode->i_nlink++; | |
45 | mark_inode_dirty(inode); | |
46 | } | |
47 | ||
48 | static inline void ext2_dec_count(struct inode *inode) | |
49 | { | |
50 | inode->i_nlink--; | |
51 | mark_inode_dirty(inode); | |
52 | } | |
53 | ||
54 | static inline int ext2_add_nondir(struct dentry *dentry, struct inode *inode) | |
55 | { | |
56 | int err = ext2_add_link(dentry, inode); | |
57 | if (!err) { | |
58 | d_instantiate(dentry, inode); | |
59 | return 0; | |
60 | } | |
61 | ext2_dec_count(inode); | |
62 | iput(inode); | |
63 | return err; | |
64 | } | |
65 | ||
66 | /* | |
67 | * Methods themselves. | |
68 | */ | |
69 | ||
70 | static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry, struct nameidata *nd) | |
71 | { | |
72 | struct inode * inode; | |
73 | ino_t ino; | |
74 | ||
75 | if (dentry->d_name.len > EXT2_NAME_LEN) | |
76 | return ERR_PTR(-ENAMETOOLONG); | |
77 | ||
78 | ino = ext2_inode_by_name(dir, dentry); | |
79 | inode = NULL; | |
80 | if (ino) { | |
81 | inode = iget(dir->i_sb, ino); | |
82 | if (!inode) | |
83 | return ERR_PTR(-EACCES); | |
84 | } | |
85 | if (inode) | |
86 | return d_splice_alias(inode, dentry); | |
87 | d_add(dentry, inode); | |
88 | return NULL; | |
89 | } | |
90 | ||
91 | struct dentry *ext2_get_parent(struct dentry *child) | |
92 | { | |
93 | unsigned long ino; | |
94 | struct dentry *parent; | |
95 | struct inode *inode; | |
96 | struct dentry dotdot; | |
97 | ||
98 | dotdot.d_name.name = ".."; | |
99 | dotdot.d_name.len = 2; | |
100 | ||
101 | ino = ext2_inode_by_name(child->d_inode, &dotdot); | |
102 | if (!ino) | |
103 | return ERR_PTR(-ENOENT); | |
104 | inode = iget(child->d_inode->i_sb, ino); | |
105 | ||
106 | if (!inode) | |
107 | return ERR_PTR(-EACCES); | |
108 | parent = d_alloc_anon(inode); | |
109 | if (!parent) { | |
110 | iput(inode); | |
111 | parent = ERR_PTR(-ENOMEM); | |
112 | } | |
113 | return parent; | |
114 | } | |
115 | ||
116 | /* | |
117 | * By the time this is called, we already have created | |
118 | * the directory cache entry for the new file, but it | |
119 | * is so far negative - it has no inode. | |
120 | * | |
121 | * If the create succeeds, we fill in the inode information | |
122 | * with d_instantiate(). | |
123 | */ | |
124 | static int ext2_create (struct inode * dir, struct dentry * dentry, int mode, struct nameidata *nd) | |
125 | { | |
126 | struct inode * inode = ext2_new_inode (dir, mode); | |
127 | int err = PTR_ERR(inode); | |
128 | if (!IS_ERR(inode)) { | |
129 | inode->i_op = &ext2_file_inode_operations; | |
130 | inode->i_fop = &ext2_file_operations; | |
131 | if (test_opt(inode->i_sb, NOBH)) | |
132 | inode->i_mapping->a_ops = &ext2_nobh_aops; | |
133 | else | |
134 | inode->i_mapping->a_ops = &ext2_aops; | |
135 | mark_inode_dirty(inode); | |
136 | err = ext2_add_nondir(dentry, inode); | |
137 | } | |
138 | return err; | |
139 | } | |
140 | ||
141 | static int ext2_mknod (struct inode * dir, struct dentry *dentry, int mode, dev_t rdev) | |
142 | { | |
143 | struct inode * inode; | |
144 | int err; | |
145 | ||
146 | if (!new_valid_dev(rdev)) | |
147 | return -EINVAL; | |
148 | ||
149 | inode = ext2_new_inode (dir, mode); | |
150 | err = PTR_ERR(inode); | |
151 | if (!IS_ERR(inode)) { | |
152 | init_special_inode(inode, inode->i_mode, rdev); | |
153 | #ifdef CONFIG_EXT2_FS_XATTR | |
154 | inode->i_op = &ext2_special_inode_operations; | |
155 | #endif | |
156 | mark_inode_dirty(inode); | |
157 | err = ext2_add_nondir(dentry, inode); | |
158 | } | |
159 | return err; | |
160 | } | |
161 | ||
162 | static int ext2_symlink (struct inode * dir, struct dentry * dentry, | |
163 | const char * symname) | |
164 | { | |
165 | struct super_block * sb = dir->i_sb; | |
166 | int err = -ENAMETOOLONG; | |
167 | unsigned l = strlen(symname)+1; | |
168 | struct inode * inode; | |
169 | ||
170 | if (l > sb->s_blocksize) | |
171 | goto out; | |
172 | ||
173 | inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO); | |
174 | err = PTR_ERR(inode); | |
175 | if (IS_ERR(inode)) | |
176 | goto out; | |
177 | ||
178 | if (l > sizeof (EXT2_I(inode)->i_data)) { | |
179 | /* slow symlink */ | |
180 | inode->i_op = &ext2_symlink_inode_operations; | |
181 | if (test_opt(inode->i_sb, NOBH)) | |
182 | inode->i_mapping->a_ops = &ext2_nobh_aops; | |
183 | else | |
184 | inode->i_mapping->a_ops = &ext2_aops; | |
185 | err = page_symlink(inode, symname, l); | |
186 | if (err) | |
187 | goto out_fail; | |
188 | } else { | |
189 | /* fast symlink */ | |
190 | inode->i_op = &ext2_fast_symlink_inode_operations; | |
191 | memcpy((char*)(EXT2_I(inode)->i_data),symname,l); | |
192 | inode->i_size = l-1; | |
193 | } | |
194 | mark_inode_dirty(inode); | |
195 | ||
196 | err = ext2_add_nondir(dentry, inode); | |
197 | out: | |
198 | return err; | |
199 | ||
200 | out_fail: | |
201 | ext2_dec_count(inode); | |
202 | iput (inode); | |
203 | goto out; | |
204 | } | |
205 | ||
206 | static int ext2_link (struct dentry * old_dentry, struct inode * dir, | |
207 | struct dentry *dentry) | |
208 | { | |
209 | struct inode *inode = old_dentry->d_inode; | |
210 | ||
211 | if (inode->i_nlink >= EXT2_LINK_MAX) | |
212 | return -EMLINK; | |
213 | ||
214 | inode->i_ctime = CURRENT_TIME_SEC; | |
215 | ext2_inc_count(inode); | |
216 | atomic_inc(&inode->i_count); | |
217 | ||
218 | return ext2_add_nondir(dentry, inode); | |
219 | } | |
220 | ||
221 | static int ext2_mkdir(struct inode * dir, struct dentry * dentry, int mode) | |
222 | { | |
223 | struct inode * inode; | |
224 | int err = -EMLINK; | |
225 | ||
226 | if (dir->i_nlink >= EXT2_LINK_MAX) | |
227 | goto out; | |
228 | ||
229 | ext2_inc_count(dir); | |
230 | ||
231 | inode = ext2_new_inode (dir, S_IFDIR | mode); | |
232 | err = PTR_ERR(inode); | |
233 | if (IS_ERR(inode)) | |
234 | goto out_dir; | |
235 | ||
236 | inode->i_op = &ext2_dir_inode_operations; | |
237 | inode->i_fop = &ext2_dir_operations; | |
238 | if (test_opt(inode->i_sb, NOBH)) | |
239 | inode->i_mapping->a_ops = &ext2_nobh_aops; | |
240 | else | |
241 | inode->i_mapping->a_ops = &ext2_aops; | |
242 | ||
243 | ext2_inc_count(inode); | |
244 | ||
245 | err = ext2_make_empty(inode, dir); | |
246 | if (err) | |
247 | goto out_fail; | |
248 | ||
249 | err = ext2_add_link(dentry, inode); | |
250 | if (err) | |
251 | goto out_fail; | |
252 | ||
253 | d_instantiate(dentry, inode); | |
254 | out: | |
255 | return err; | |
256 | ||
257 | out_fail: | |
258 | ext2_dec_count(inode); | |
259 | ext2_dec_count(inode); | |
260 | iput(inode); | |
261 | out_dir: | |
262 | ext2_dec_count(dir); | |
263 | goto out; | |
264 | } | |
265 | ||
266 | static int ext2_unlink(struct inode * dir, struct dentry *dentry) | |
267 | { | |
268 | struct inode * inode = dentry->d_inode; | |
269 | struct ext2_dir_entry_2 * de; | |
270 | struct page * page; | |
271 | int err = -ENOENT; | |
272 | ||
273 | de = ext2_find_entry (dir, dentry, &page); | |
274 | if (!de) | |
275 | goto out; | |
276 | ||
277 | err = ext2_delete_entry (de, page); | |
278 | if (err) | |
279 | goto out; | |
280 | ||
281 | inode->i_ctime = dir->i_ctime; | |
282 | ext2_dec_count(inode); | |
283 | err = 0; | |
284 | out: | |
285 | return err; | |
286 | } | |
287 | ||
288 | static int ext2_rmdir (struct inode * dir, struct dentry *dentry) | |
289 | { | |
290 | struct inode * inode = dentry->d_inode; | |
291 | int err = -ENOTEMPTY; | |
292 | ||
293 | if (ext2_empty_dir(inode)) { | |
294 | err = ext2_unlink(dir, dentry); | |
295 | if (!err) { | |
296 | inode->i_size = 0; | |
297 | ext2_dec_count(inode); | |
298 | ext2_dec_count(dir); | |
299 | } | |
300 | } | |
301 | return err; | |
302 | } | |
303 | ||
304 | static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry, | |
305 | struct inode * new_dir, struct dentry * new_dentry ) | |
306 | { | |
307 | struct inode * old_inode = old_dentry->d_inode; | |
308 | struct inode * new_inode = new_dentry->d_inode; | |
309 | struct page * dir_page = NULL; | |
310 | struct ext2_dir_entry_2 * dir_de = NULL; | |
311 | struct page * old_page; | |
312 | struct ext2_dir_entry_2 * old_de; | |
313 | int err = -ENOENT; | |
314 | ||
315 | old_de = ext2_find_entry (old_dir, old_dentry, &old_page); | |
316 | if (!old_de) | |
317 | goto out; | |
318 | ||
319 | if (S_ISDIR(old_inode->i_mode)) { | |
320 | err = -EIO; | |
321 | dir_de = ext2_dotdot(old_inode, &dir_page); | |
322 | if (!dir_de) | |
323 | goto out_old; | |
324 | } | |
325 | ||
326 | if (new_inode) { | |
327 | struct page *new_page; | |
328 | struct ext2_dir_entry_2 *new_de; | |
329 | ||
330 | err = -ENOTEMPTY; | |
331 | if (dir_de && !ext2_empty_dir (new_inode)) | |
332 | goto out_dir; | |
333 | ||
334 | err = -ENOENT; | |
335 | new_de = ext2_find_entry (new_dir, new_dentry, &new_page); | |
336 | if (!new_de) | |
337 | goto out_dir; | |
338 | ext2_inc_count(old_inode); | |
339 | ext2_set_link(new_dir, new_de, new_page, old_inode); | |
340 | new_inode->i_ctime = CURRENT_TIME_SEC; | |
341 | if (dir_de) | |
342 | new_inode->i_nlink--; | |
343 | ext2_dec_count(new_inode); | |
344 | } else { | |
345 | if (dir_de) { | |
346 | err = -EMLINK; | |
347 | if (new_dir->i_nlink >= EXT2_LINK_MAX) | |
348 | goto out_dir; | |
349 | } | |
350 | ext2_inc_count(old_inode); | |
351 | err = ext2_add_link(new_dentry, old_inode); | |
352 | if (err) { | |
353 | ext2_dec_count(old_inode); | |
354 | goto out_dir; | |
355 | } | |
356 | if (dir_de) | |
357 | ext2_inc_count(new_dir); | |
358 | } | |
359 | ||
360 | /* | |
361 | * Like most other Unix systems, set the ctime for inodes on a | |
362 | * rename. | |
363 | * ext2_dec_count() will mark the inode dirty. | |
364 | */ | |
365 | old_inode->i_ctime = CURRENT_TIME_SEC; | |
366 | ||
367 | ext2_delete_entry (old_de, old_page); | |
368 | ext2_dec_count(old_inode); | |
369 | ||
370 | if (dir_de) { | |
371 | ext2_set_link(old_inode, dir_de, dir_page, new_dir); | |
372 | ext2_dec_count(old_dir); | |
373 | } | |
374 | return 0; | |
375 | ||
376 | ||
377 | out_dir: | |
378 | if (dir_de) { | |
379 | kunmap(dir_page); | |
380 | page_cache_release(dir_page); | |
381 | } | |
382 | out_old: | |
383 | kunmap(old_page); | |
384 | page_cache_release(old_page); | |
385 | out: | |
386 | return err; | |
387 | } | |
388 | ||
389 | struct inode_operations ext2_dir_inode_operations = { | |
390 | .create = ext2_create, | |
391 | .lookup = ext2_lookup, | |
392 | .link = ext2_link, | |
393 | .unlink = ext2_unlink, | |
394 | .symlink = ext2_symlink, | |
395 | .mkdir = ext2_mkdir, | |
396 | .rmdir = ext2_rmdir, | |
397 | .mknod = ext2_mknod, | |
398 | .rename = ext2_rename, | |
399 | #ifdef CONFIG_EXT2_FS_XATTR | |
400 | .setxattr = generic_setxattr, | |
401 | .getxattr = generic_getxattr, | |
402 | .listxattr = ext2_listxattr, | |
403 | .removexattr = generic_removexattr, | |
404 | #endif | |
405 | .setattr = ext2_setattr, | |
406 | .permission = ext2_permission, | |
407 | }; | |
408 | ||
409 | struct inode_operations ext2_special_inode_operations = { | |
410 | #ifdef CONFIG_EXT2_FS_XATTR | |
411 | .setxattr = generic_setxattr, | |
412 | .getxattr = generic_getxattr, | |
413 | .listxattr = ext2_listxattr, | |
414 | .removexattr = generic_removexattr, | |
415 | #endif | |
416 | .setattr = ext2_setattr, | |
417 | .permission = ext2_permission, | |
418 | }; |