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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 <linux/quotaops.h>
35#include "ext2.h"
36#include "xattr.h"
37#include "acl.h"
38#include "xip.h"
39
40static inline int ext2_add_nondir(struct dentry *dentry, struct inode *inode)
41{
42 int err = ext2_add_link(dentry, inode);
43 if (!err) {
44 d_instantiate(dentry, inode);
45 unlock_new_inode(inode);
46 return 0;
47 }
48 inode_dec_link_count(inode);
49 unlock_new_inode(inode);
50 iput(inode);
51 return err;
52}
53
54/*
55 * Methods themselves.
56 */
57
58static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry, struct nameidata *nd)
59{
60 struct inode * inode;
61 ino_t ino;
62
63 if (dentry->d_name.len > EXT2_NAME_LEN)
64 return ERR_PTR(-ENAMETOOLONG);
65
66 ino = ext2_inode_by_name(dir, &dentry->d_name);
67 inode = NULL;
68 if (ino) {
69 inode = ext2_iget(dir->i_sb, ino);
70 if (inode == ERR_PTR(-ESTALE)) {
71 ext2_error(dir->i_sb, __func__,
72 "deleted inode referenced: %lu",
73 (unsigned long) ino);
74 return ERR_PTR(-EIO);
75 }
76 }
77 return d_splice_alias(inode, dentry);
78}
79
80struct dentry *ext2_get_parent(struct dentry *child)
81{
82 struct qstr dotdot = QSTR_INIT("..", 2);
83 unsigned long ino = ext2_inode_by_name(child->d_inode, &dotdot);
84 if (!ino)
85 return ERR_PTR(-ENOENT);
86 return d_obtain_alias(ext2_iget(child->d_inode->i_sb, ino));
87}
88
89/*
90 * By the time this is called, we already have created
91 * the directory cache entry for the new file, but it
92 * is so far negative - it has no inode.
93 *
94 * If the create succeeds, we fill in the inode information
95 * with d_instantiate().
96 */
97static int ext2_create (struct inode * dir, struct dentry * dentry, umode_t mode, struct nameidata *nd)
98{
99 struct inode *inode;
100
101 dquot_initialize(dir);
102
103 inode = ext2_new_inode(dir, mode, &dentry->d_name);
104 if (IS_ERR(inode))
105 return PTR_ERR(inode);
106
107 inode->i_op = &ext2_file_inode_operations;
108 if (ext2_use_xip(inode->i_sb)) {
109 inode->i_mapping->a_ops = &ext2_aops_xip;
110 inode->i_fop = &ext2_xip_file_operations;
111 } else if (test_opt(inode->i_sb, NOBH)) {
112 inode->i_mapping->a_ops = &ext2_nobh_aops;
113 inode->i_fop = &ext2_file_operations;
114 } else {
115 inode->i_mapping->a_ops = &ext2_aops;
116 inode->i_fop = &ext2_file_operations;
117 }
118 mark_inode_dirty(inode);
119 return ext2_add_nondir(dentry, inode);
120}
121
122static int ext2_mknod (struct inode * dir, struct dentry *dentry, umode_t mode, dev_t rdev)
123{
124 struct inode * inode;
125 int err;
126
127 if (!new_valid_dev(rdev))
128 return -EINVAL;
129
130 dquot_initialize(dir);
131
132 inode = ext2_new_inode (dir, mode, &dentry->d_name);
133 err = PTR_ERR(inode);
134 if (!IS_ERR(inode)) {
135 init_special_inode(inode, inode->i_mode, rdev);
136#ifdef CONFIG_EXT2_FS_XATTR
137 inode->i_op = &ext2_special_inode_operations;
138#endif
139 mark_inode_dirty(inode);
140 err = ext2_add_nondir(dentry, inode);
141 }
142 return err;
143}
144
145static int ext2_symlink (struct inode * dir, struct dentry * dentry,
146 const char * symname)
147{
148 struct super_block * sb = dir->i_sb;
149 int err = -ENAMETOOLONG;
150 unsigned l = strlen(symname)+1;
151 struct inode * inode;
152
153 if (l > sb->s_blocksize)
154 goto out;
155
156 dquot_initialize(dir);
157
158 inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO, &dentry->d_name);
159 err = PTR_ERR(inode);
160 if (IS_ERR(inode))
161 goto out;
162
163 if (l > sizeof (EXT2_I(inode)->i_data)) {
164 /* slow symlink */
165 inode->i_op = &ext2_symlink_inode_operations;
166 if (test_opt(inode->i_sb, NOBH))
167 inode->i_mapping->a_ops = &ext2_nobh_aops;
168 else
169 inode->i_mapping->a_ops = &ext2_aops;
170 err = page_symlink(inode, symname, l);
171 if (err)
172 goto out_fail;
173 } else {
174 /* fast symlink */
175 inode->i_op = &ext2_fast_symlink_inode_operations;
176 memcpy((char*)(EXT2_I(inode)->i_data),symname,l);
177 inode->i_size = l-1;
178 }
179 mark_inode_dirty(inode);
180
181 err = ext2_add_nondir(dentry, inode);
182out:
183 return err;
184
185out_fail:
186 inode_dec_link_count(inode);
187 unlock_new_inode(inode);
188 iput (inode);
189 goto out;
190}
191
192static int ext2_link (struct dentry * old_dentry, struct inode * dir,
193 struct dentry *dentry)
194{
195 struct inode *inode = old_dentry->d_inode;
196 int err;
197
198 dquot_initialize(dir);
199
200 inode->i_ctime = CURRENT_TIME_SEC;
201 inode_inc_link_count(inode);
202 ihold(inode);
203
204 err = ext2_add_link(dentry, inode);
205 if (!err) {
206 d_instantiate(dentry, inode);
207 return 0;
208 }
209 inode_dec_link_count(inode);
210 iput(inode);
211 return err;
212}
213
214static int ext2_mkdir(struct inode * dir, struct dentry * dentry, umode_t mode)
215{
216 struct inode * inode;
217 int err;
218
219 dquot_initialize(dir);
220
221 inode_inc_link_count(dir);
222
223 inode = ext2_new_inode(dir, S_IFDIR | mode, &dentry->d_name);
224 err = PTR_ERR(inode);
225 if (IS_ERR(inode))
226 goto out_dir;
227
228 inode->i_op = &ext2_dir_inode_operations;
229 inode->i_fop = &ext2_dir_operations;
230 if (test_opt(inode->i_sb, NOBH))
231 inode->i_mapping->a_ops = &ext2_nobh_aops;
232 else
233 inode->i_mapping->a_ops = &ext2_aops;
234
235 inode_inc_link_count(inode);
236
237 err = ext2_make_empty(inode, dir);
238 if (err)
239 goto out_fail;
240
241 err = ext2_add_link(dentry, inode);
242 if (err)
243 goto out_fail;
244
245 d_instantiate(dentry, inode);
246 unlock_new_inode(inode);
247out:
248 return err;
249
250out_fail:
251 inode_dec_link_count(inode);
252 inode_dec_link_count(inode);
253 unlock_new_inode(inode);
254 iput(inode);
255out_dir:
256 inode_dec_link_count(dir);
257 goto out;
258}
259
260static int ext2_unlink(struct inode * dir, struct dentry *dentry)
261{
262 struct inode * inode = dentry->d_inode;
263 struct ext2_dir_entry_2 * de;
264 struct page * page;
265 int err = -ENOENT;
266
267 dquot_initialize(dir);
268
269 de = ext2_find_entry (dir, &dentry->d_name, &page);
270 if (!de)
271 goto out;
272
273 err = ext2_delete_entry (de, page);
274 if (err)
275 goto out;
276
277 inode->i_ctime = dir->i_ctime;
278 inode_dec_link_count(inode);
279 err = 0;
280out:
281 return err;
282}
283
284static int ext2_rmdir (struct inode * dir, struct dentry *dentry)
285{
286 struct inode * inode = dentry->d_inode;
287 int err = -ENOTEMPTY;
288
289 if (ext2_empty_dir(inode)) {
290 err = ext2_unlink(dir, dentry);
291 if (!err) {
292 inode->i_size = 0;
293 inode_dec_link_count(inode);
294 inode_dec_link_count(dir);
295 }
296 }
297 return err;
298}
299
300static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry,
301 struct inode * new_dir, struct dentry * new_dentry )
302{
303 struct inode * old_inode = old_dentry->d_inode;
304 struct inode * new_inode = new_dentry->d_inode;
305 struct page * dir_page = NULL;
306 struct ext2_dir_entry_2 * dir_de = NULL;
307 struct page * old_page;
308 struct ext2_dir_entry_2 * old_de;
309 int err = -ENOENT;
310
311 dquot_initialize(old_dir);
312 dquot_initialize(new_dir);
313
314 old_de = ext2_find_entry (old_dir, &old_dentry->d_name, &old_page);
315 if (!old_de)
316 goto out;
317
318 if (S_ISDIR(old_inode->i_mode)) {
319 err = -EIO;
320 dir_de = ext2_dotdot(old_inode, &dir_page);
321 if (!dir_de)
322 goto out_old;
323 }
324
325 if (new_inode) {
326 struct page *new_page;
327 struct ext2_dir_entry_2 *new_de;
328
329 err = -ENOTEMPTY;
330 if (dir_de && !ext2_empty_dir (new_inode))
331 goto out_dir;
332
333 err = -ENOENT;
334 new_de = ext2_find_entry (new_dir, &new_dentry->d_name, &new_page);
335 if (!new_de)
336 goto out_dir;
337 ext2_set_link(new_dir, new_de, new_page, old_inode, 1);
338 new_inode->i_ctime = CURRENT_TIME_SEC;
339 if (dir_de)
340 drop_nlink(new_inode);
341 inode_dec_link_count(new_inode);
342 } else {
343 err = ext2_add_link(new_dentry, old_inode);
344 if (err)
345 goto out_dir;
346 if (dir_de)
347 inode_inc_link_count(new_dir);
348 }
349
350 /*
351 * Like most other Unix systems, set the ctime for inodes on a
352 * rename.
353 */
354 old_inode->i_ctime = CURRENT_TIME_SEC;
355 mark_inode_dirty(old_inode);
356
357 ext2_delete_entry (old_de, old_page);
358
359 if (dir_de) {
360 if (old_dir != new_dir)
361 ext2_set_link(old_inode, dir_de, dir_page, new_dir, 0);
362 else {
363 kunmap(dir_page);
364 page_cache_release(dir_page);
365 }
366 inode_dec_link_count(old_dir);
367 }
368 return 0;
369
370
371out_dir:
372 if (dir_de) {
373 kunmap(dir_page);
374 page_cache_release(dir_page);
375 }
376out_old:
377 kunmap(old_page);
378 page_cache_release(old_page);
379out:
380 return err;
381}
382
383const struct inode_operations ext2_dir_inode_operations = {
384 .create = ext2_create,
385 .lookup = ext2_lookup,
386 .link = ext2_link,
387 .unlink = ext2_unlink,
388 .symlink = ext2_symlink,
389 .mkdir = ext2_mkdir,
390 .rmdir = ext2_rmdir,
391 .mknod = ext2_mknod,
392 .rename = ext2_rename,
393#ifdef CONFIG_EXT2_FS_XATTR
394 .setxattr = generic_setxattr,
395 .getxattr = generic_getxattr,
396 .listxattr = ext2_listxattr,
397 .removexattr = generic_removexattr,
398#endif
399 .setattr = ext2_setattr,
400 .get_acl = ext2_get_acl,
401};
402
403const struct inode_operations ext2_special_inode_operations = {
404#ifdef CONFIG_EXT2_FS_XATTR
405 .setxattr = generic_setxattr,
406 .getxattr = generic_getxattr,
407 .listxattr = ext2_listxattr,
408 .removexattr = generic_removexattr,
409#endif
410 .setattr = ext2_setattr,
411 .get_acl = ext2_get_acl,
412};