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 #include "xip.h"
38
39 static inline int ext2_add_nondir(struct dentry *dentry, struct inode *inode)
40 {
41 int err = ext2_add_link(dentry, inode);
42 if (!err) {
43 d_instantiate(dentry, inode);
44 return 0;
45 }
46 inode_dec_link_count(inode);
47 iput(inode);
48 return err;
49 }
50
51 /*
52 * Methods themselves.
53 */
54
55 static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry, struct nameidata *nd)
56 {
57 struct inode * inode;
58 ino_t ino;
59
60 if (dentry->d_name.len > EXT2_NAME_LEN)
61 return ERR_PTR(-ENAMETOOLONG);
62
63 ino = ext2_inode_by_name(dir, dentry);
64 inode = NULL;
65 if (ino) {
66 inode = ext2_iget(dir->i_sb, ino);
67 if (IS_ERR(inode))
68 return ERR_CAST(inode);
69 }
70 return d_splice_alias(inode, dentry);
71 }
72
73 struct dentry *ext2_get_parent(struct dentry *child)
74 {
75 unsigned long ino;
76 struct dentry *parent;
77 struct inode *inode;
78 struct dentry dotdot;
79
80 dotdot.d_name.name = "..";
81 dotdot.d_name.len = 2;
82
83 ino = ext2_inode_by_name(child->d_inode, &dotdot);
84 if (!ino)
85 return ERR_PTR(-ENOENT);
86 inode = ext2_iget(child->d_inode->i_sb, ino);
87
88 if (IS_ERR(inode))
89 return ERR_CAST(inode);
90 parent = d_alloc_anon(inode);
91 if (!parent) {
92 iput(inode);
93 parent = ERR_PTR(-ENOMEM);
94 }
95 return parent;
96 }
97
98 /*
99 * By the time this is called, we already have created
100 * the directory cache entry for the new file, but it
101 * is so far negative - it has no inode.
102 *
103 * If the create succeeds, we fill in the inode information
104 * with d_instantiate().
105 */
106 static int ext2_create (struct inode * dir, struct dentry * dentry, int mode, struct nameidata *nd)
107 {
108 struct inode * inode = ext2_new_inode (dir, mode);
109 int err = PTR_ERR(inode);
110 if (!IS_ERR(inode)) {
111 inode->i_op = &ext2_file_inode_operations;
112 if (ext2_use_xip(inode->i_sb)) {
113 inode->i_mapping->a_ops = &ext2_aops_xip;
114 inode->i_fop = &ext2_xip_file_operations;
115 } else if (test_opt(inode->i_sb, NOBH)) {
116 inode->i_mapping->a_ops = &ext2_nobh_aops;
117 inode->i_fop = &ext2_file_operations;
118 } else {
119 inode->i_mapping->a_ops = &ext2_aops;
120 inode->i_fop = &ext2_file_operations;
121 }
122 mark_inode_dirty(inode);
123 err = ext2_add_nondir(dentry, inode);
124 }
125 return err;
126 }
127
128 static int ext2_mknod (struct inode * dir, struct dentry *dentry, int mode, dev_t rdev)
129 {
130 struct inode * inode;
131 int err;
132
133 if (!new_valid_dev(rdev))
134 return -EINVAL;
135
136 inode = ext2_new_inode (dir, mode);
137 err = PTR_ERR(inode);
138 if (!IS_ERR(inode)) {
139 init_special_inode(inode, inode->i_mode, rdev);
140 #ifdef CONFIG_EXT2_FS_XATTR
141 inode->i_op = &ext2_special_inode_operations;
142 #endif
143 mark_inode_dirty(inode);
144 err = ext2_add_nondir(dentry, inode);
145 }
146 return err;
147 }
148
149 static int ext2_symlink (struct inode * dir, struct dentry * dentry,
150 const char * symname)
151 {
152 struct super_block * sb = dir->i_sb;
153 int err = -ENAMETOOLONG;
154 unsigned l = strlen(symname)+1;
155 struct inode * inode;
156
157 if (l > sb->s_blocksize)
158 goto out;
159
160 inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO);
161 err = PTR_ERR(inode);
162 if (IS_ERR(inode))
163 goto out;
164
165 if (l > sizeof (EXT2_I(inode)->i_data)) {
166 /* slow symlink */
167 inode->i_op = &ext2_symlink_inode_operations;
168 if (test_opt(inode->i_sb, NOBH))
169 inode->i_mapping->a_ops = &ext2_nobh_aops;
170 else
171 inode->i_mapping->a_ops = &ext2_aops;
172 err = page_symlink(inode, symname, l);
173 if (err)
174 goto out_fail;
175 } else {
176 /* fast symlink */
177 inode->i_op = &ext2_fast_symlink_inode_operations;
178 memcpy((char*)(EXT2_I(inode)->i_data),symname,l);
179 inode->i_size = l-1;
180 }
181 mark_inode_dirty(inode);
182
183 err = ext2_add_nondir(dentry, inode);
184 out:
185 return err;
186
187 out_fail:
188 inode_dec_link_count(inode);
189 iput (inode);
190 goto out;
191 }
192
193 static int ext2_link (struct dentry * old_dentry, struct inode * dir,
194 struct dentry *dentry)
195 {
196 struct inode *inode = old_dentry->d_inode;
197
198 if (inode->i_nlink >= EXT2_LINK_MAX)
199 return -EMLINK;
200
201 inode->i_ctime = CURRENT_TIME_SEC;
202 inode_inc_link_count(inode);
203 atomic_inc(&inode->i_count);
204
205 return ext2_add_nondir(dentry, inode);
206 }
207
208 static int ext2_mkdir(struct inode * dir, struct dentry * dentry, int mode)
209 {
210 struct inode * inode;
211 int err = -EMLINK;
212
213 if (dir->i_nlink >= EXT2_LINK_MAX)
214 goto out;
215
216 inode_inc_link_count(dir);
217
218 inode = ext2_new_inode (dir, S_IFDIR | mode);
219 err = PTR_ERR(inode);
220 if (IS_ERR(inode))
221 goto out_dir;
222
223 inode->i_op = &ext2_dir_inode_operations;
224 inode->i_fop = &ext2_dir_operations;
225 if (test_opt(inode->i_sb, NOBH))
226 inode->i_mapping->a_ops = &ext2_nobh_aops;
227 else
228 inode->i_mapping->a_ops = &ext2_aops;
229
230 inode_inc_link_count(inode);
231
232 err = ext2_make_empty(inode, dir);
233 if (err)
234 goto out_fail;
235
236 err = ext2_add_link(dentry, inode);
237 if (err)
238 goto out_fail;
239
240 d_instantiate(dentry, inode);
241 out:
242 return err;
243
244 out_fail:
245 inode_dec_link_count(inode);
246 inode_dec_link_count(inode);
247 iput(inode);
248 out_dir:
249 inode_dec_link_count(dir);
250 goto out;
251 }
252
253 static int ext2_unlink(struct inode * dir, struct dentry *dentry)
254 {
255 struct inode * inode = dentry->d_inode;
256 struct ext2_dir_entry_2 * de;
257 struct page * page;
258 int err = -ENOENT;
259
260 de = ext2_find_entry (dir, dentry, &page);
261 if (!de)
262 goto out;
263
264 err = ext2_delete_entry (de, page);
265 if (err)
266 goto out;
267
268 inode->i_ctime = dir->i_ctime;
269 inode_dec_link_count(inode);
270 err = 0;
271 out:
272 return err;
273 }
274
275 static int ext2_rmdir (struct inode * dir, struct dentry *dentry)
276 {
277 struct inode * inode = dentry->d_inode;
278 int err = -ENOTEMPTY;
279
280 if (ext2_empty_dir(inode)) {
281 err = ext2_unlink(dir, dentry);
282 if (!err) {
283 inode->i_size = 0;
284 inode_dec_link_count(inode);
285 inode_dec_link_count(dir);
286 }
287 }
288 return err;
289 }
290
291 static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry,
292 struct inode * new_dir, struct dentry * new_dentry )
293 {
294 struct inode * old_inode = old_dentry->d_inode;
295 struct inode * new_inode = new_dentry->d_inode;
296 struct page * dir_page = NULL;
297 struct ext2_dir_entry_2 * dir_de = NULL;
298 struct page * old_page;
299 struct ext2_dir_entry_2 * old_de;
300 int err = -ENOENT;
301
302 old_de = ext2_find_entry (old_dir, old_dentry, &old_page);
303 if (!old_de)
304 goto out;
305
306 if (S_ISDIR(old_inode->i_mode)) {
307 err = -EIO;
308 dir_de = ext2_dotdot(old_inode, &dir_page);
309 if (!dir_de)
310 goto out_old;
311 }
312
313 if (new_inode) {
314 struct page *new_page;
315 struct ext2_dir_entry_2 *new_de;
316
317 err = -ENOTEMPTY;
318 if (dir_de && !ext2_empty_dir (new_inode))
319 goto out_dir;
320
321 err = -ENOENT;
322 new_de = ext2_find_entry (new_dir, new_dentry, &new_page);
323 if (!new_de)
324 goto out_dir;
325 inode_inc_link_count(old_inode);
326 ext2_set_link(new_dir, new_de, new_page, old_inode);
327 new_inode->i_ctime = CURRENT_TIME_SEC;
328 if (dir_de)
329 drop_nlink(new_inode);
330 inode_dec_link_count(new_inode);
331 } else {
332 if (dir_de) {
333 err = -EMLINK;
334 if (new_dir->i_nlink >= EXT2_LINK_MAX)
335 goto out_dir;
336 }
337 inode_inc_link_count(old_inode);
338 err = ext2_add_link(new_dentry, old_inode);
339 if (err) {
340 inode_dec_link_count(old_inode);
341 goto out_dir;
342 }
343 if (dir_de)
344 inode_inc_link_count(new_dir);
345 }
346
347 /*
348 * Like most other Unix systems, set the ctime for inodes on a
349 * rename.
350 * inode_dec_link_count() will mark the inode dirty.
351 */
352 old_inode->i_ctime = CURRENT_TIME_SEC;
353
354 ext2_delete_entry (old_de, old_page);
355 inode_dec_link_count(old_inode);
356
357 if (dir_de) {
358 ext2_set_link(old_inode, dir_de, dir_page, new_dir);
359 inode_dec_link_count(old_dir);
360 }
361 return 0;
362
363
364 out_dir:
365 if (dir_de) {
366 kunmap(dir_page);
367 page_cache_release(dir_page);
368 }
369 out_old:
370 kunmap(old_page);
371 page_cache_release(old_page);
372 out:
373 return err;
374 }
375
376 const struct inode_operations ext2_dir_inode_operations = {
377 .create = ext2_create,
378 .lookup = ext2_lookup,
379 .link = ext2_link,
380 .unlink = ext2_unlink,
381 .symlink = ext2_symlink,
382 .mkdir = ext2_mkdir,
383 .rmdir = ext2_rmdir,
384 .mknod = ext2_mknod,
385 .rename = ext2_rename,
386 #ifdef CONFIG_EXT2_FS_XATTR
387 .setxattr = generic_setxattr,
388 .getxattr = generic_getxattr,
389 .listxattr = ext2_listxattr,
390 .removexattr = generic_removexattr,
391 #endif
392 .setattr = ext2_setattr,
393 .permission = ext2_permission,
394 };
395
396 const struct inode_operations ext2_special_inode_operations = {
397 #ifdef CONFIG_EXT2_FS_XATTR
398 .setxattr = generic_setxattr,
399 .getxattr = generic_getxattr,
400 .listxattr = ext2_listxattr,
401 .removexattr = generic_removexattr,
402 #endif
403 .setattr = ext2_setattr,
404 .permission = ext2_permission,
405 };
406
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