diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /fs/minix/dir.c |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'fs/minix/dir.c')
-rw-r--r-- | fs/minix/dir.c | 409 |
1 files changed, 409 insertions, 0 deletions
diff --git a/fs/minix/dir.c b/fs/minix/dir.c new file mode 100644 index 000000000000..732502aabc05 --- /dev/null +++ b/fs/minix/dir.c | |||
@@ -0,0 +1,409 @@ | |||
1 | /* | ||
2 | * linux/fs/minix/dir.c | ||
3 | * | ||
4 | * Copyright (C) 1991, 1992 Linus Torvalds | ||
5 | * | ||
6 | * minix directory handling functions | ||
7 | */ | ||
8 | |||
9 | #include "minix.h" | ||
10 | #include <linux/highmem.h> | ||
11 | #include <linux/smp_lock.h> | ||
12 | |||
13 | typedef struct minix_dir_entry minix_dirent; | ||
14 | |||
15 | static int minix_readdir(struct file *, void *, filldir_t); | ||
16 | |||
17 | struct file_operations minix_dir_operations = { | ||
18 | .read = generic_read_dir, | ||
19 | .readdir = minix_readdir, | ||
20 | .fsync = minix_sync_file, | ||
21 | }; | ||
22 | |||
23 | static inline void dir_put_page(struct page *page) | ||
24 | { | ||
25 | kunmap(page); | ||
26 | page_cache_release(page); | ||
27 | } | ||
28 | |||
29 | /* | ||
30 | * Return the offset into page `page_nr' of the last valid | ||
31 | * byte in that page, plus one. | ||
32 | */ | ||
33 | static unsigned | ||
34 | minix_last_byte(struct inode *inode, unsigned long page_nr) | ||
35 | { | ||
36 | unsigned last_byte = PAGE_CACHE_SIZE; | ||
37 | |||
38 | if (page_nr == (inode->i_size >> PAGE_CACHE_SHIFT)) | ||
39 | last_byte = inode->i_size & (PAGE_CACHE_SIZE - 1); | ||
40 | return last_byte; | ||
41 | } | ||
42 | |||
43 | static inline unsigned long dir_pages(struct inode *inode) | ||
44 | { | ||
45 | return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT; | ||
46 | } | ||
47 | |||
48 | static int dir_commit_chunk(struct page *page, unsigned from, unsigned to) | ||
49 | { | ||
50 | struct inode *dir = (struct inode *)page->mapping->host; | ||
51 | int err = 0; | ||
52 | page->mapping->a_ops->commit_write(NULL, page, from, to); | ||
53 | if (IS_DIRSYNC(dir)) | ||
54 | err = write_one_page(page, 1); | ||
55 | else | ||
56 | unlock_page(page); | ||
57 | return err; | ||
58 | } | ||
59 | |||
60 | static struct page * dir_get_page(struct inode *dir, unsigned long n) | ||
61 | { | ||
62 | struct address_space *mapping = dir->i_mapping; | ||
63 | struct page *page = read_cache_page(mapping, n, | ||
64 | (filler_t*)mapping->a_ops->readpage, NULL); | ||
65 | if (!IS_ERR(page)) { | ||
66 | wait_on_page_locked(page); | ||
67 | kmap(page); | ||
68 | if (!PageUptodate(page)) | ||
69 | goto fail; | ||
70 | } | ||
71 | return page; | ||
72 | |||
73 | fail: | ||
74 | dir_put_page(page); | ||
75 | return ERR_PTR(-EIO); | ||
76 | } | ||
77 | |||
78 | static inline void *minix_next_entry(void *de, struct minix_sb_info *sbi) | ||
79 | { | ||
80 | return (void*)((char*)de + sbi->s_dirsize); | ||
81 | } | ||
82 | |||
83 | static int minix_readdir(struct file * filp, void * dirent, filldir_t filldir) | ||
84 | { | ||
85 | unsigned long pos = filp->f_pos; | ||
86 | struct inode *inode = filp->f_dentry->d_inode; | ||
87 | struct super_block *sb = inode->i_sb; | ||
88 | unsigned offset = pos & ~PAGE_CACHE_MASK; | ||
89 | unsigned long n = pos >> PAGE_CACHE_SHIFT; | ||
90 | unsigned long npages = dir_pages(inode); | ||
91 | struct minix_sb_info *sbi = minix_sb(sb); | ||
92 | unsigned chunk_size = sbi->s_dirsize; | ||
93 | |||
94 | lock_kernel(); | ||
95 | |||
96 | pos = (pos + chunk_size-1) & ~(chunk_size-1); | ||
97 | if (pos >= inode->i_size) | ||
98 | goto done; | ||
99 | |||
100 | for ( ; n < npages; n++, offset = 0) { | ||
101 | char *p, *kaddr, *limit; | ||
102 | struct page *page = dir_get_page(inode, n); | ||
103 | |||
104 | if (IS_ERR(page)) | ||
105 | continue; | ||
106 | kaddr = (char *)page_address(page); | ||
107 | p = kaddr+offset; | ||
108 | limit = kaddr + minix_last_byte(inode, n) - chunk_size; | ||
109 | for ( ; p <= limit ; p = minix_next_entry(p, sbi)) { | ||
110 | minix_dirent *de = (minix_dirent *)p; | ||
111 | if (de->inode) { | ||
112 | int over; | ||
113 | unsigned l = strnlen(de->name,sbi->s_namelen); | ||
114 | |||
115 | offset = p - kaddr; | ||
116 | over = filldir(dirent, de->name, l, | ||
117 | (n<<PAGE_CACHE_SHIFT) | offset, | ||
118 | de->inode, DT_UNKNOWN); | ||
119 | if (over) { | ||
120 | dir_put_page(page); | ||
121 | goto done; | ||
122 | } | ||
123 | } | ||
124 | } | ||
125 | dir_put_page(page); | ||
126 | } | ||
127 | |||
128 | done: | ||
129 | filp->f_pos = (n << PAGE_CACHE_SHIFT) | offset; | ||
130 | unlock_kernel(); | ||
131 | return 0; | ||
132 | } | ||
133 | |||
134 | static inline int namecompare(int len, int maxlen, | ||
135 | const char * name, const char * buffer) | ||
136 | { | ||
137 | if (len < maxlen && buffer[len]) | ||
138 | return 0; | ||
139 | return !memcmp(name, buffer, len); | ||
140 | } | ||
141 | |||
142 | /* | ||
143 | * minix_find_entry() | ||
144 | * | ||
145 | * finds an entry in the specified directory with the wanted name. It | ||
146 | * returns the cache buffer in which the entry was found, and the entry | ||
147 | * itself (as a parameter - res_dir). It does NOT read the inode of the | ||
148 | * entry - you'll have to do that yourself if you want to. | ||
149 | */ | ||
150 | minix_dirent *minix_find_entry(struct dentry *dentry, struct page **res_page) | ||
151 | { | ||
152 | const char * name = dentry->d_name.name; | ||
153 | int namelen = dentry->d_name.len; | ||
154 | struct inode * dir = dentry->d_parent->d_inode; | ||
155 | struct super_block * sb = dir->i_sb; | ||
156 | struct minix_sb_info * sbi = minix_sb(sb); | ||
157 | unsigned long n; | ||
158 | unsigned long npages = dir_pages(dir); | ||
159 | struct page *page = NULL; | ||
160 | struct minix_dir_entry *de; | ||
161 | |||
162 | *res_page = NULL; | ||
163 | |||
164 | for (n = 0; n < npages; n++) { | ||
165 | char *kaddr; | ||
166 | page = dir_get_page(dir, n); | ||
167 | if (IS_ERR(page)) | ||
168 | continue; | ||
169 | |||
170 | kaddr = (char*)page_address(page); | ||
171 | de = (struct minix_dir_entry *) kaddr; | ||
172 | kaddr += minix_last_byte(dir, n) - sbi->s_dirsize; | ||
173 | for ( ; (char *) de <= kaddr ; de = minix_next_entry(de,sbi)) { | ||
174 | if (!de->inode) | ||
175 | continue; | ||
176 | if (namecompare(namelen,sbi->s_namelen,name,de->name)) | ||
177 | goto found; | ||
178 | } | ||
179 | dir_put_page(page); | ||
180 | } | ||
181 | return NULL; | ||
182 | |||
183 | found: | ||
184 | *res_page = page; | ||
185 | return de; | ||
186 | } | ||
187 | |||
188 | int minix_add_link(struct dentry *dentry, struct inode *inode) | ||
189 | { | ||
190 | struct inode *dir = dentry->d_parent->d_inode; | ||
191 | const char * name = dentry->d_name.name; | ||
192 | int namelen = dentry->d_name.len; | ||
193 | struct super_block * sb = dir->i_sb; | ||
194 | struct minix_sb_info * sbi = minix_sb(sb); | ||
195 | struct page *page = NULL; | ||
196 | struct minix_dir_entry * de; | ||
197 | unsigned long npages = dir_pages(dir); | ||
198 | unsigned long n; | ||
199 | char *kaddr; | ||
200 | unsigned from, to; | ||
201 | int err; | ||
202 | |||
203 | /* | ||
204 | * We take care of directory expansion in the same loop | ||
205 | * This code plays outside i_size, so it locks the page | ||
206 | * to protect that region. | ||
207 | */ | ||
208 | for (n = 0; n <= npages; n++) { | ||
209 | char *dir_end; | ||
210 | |||
211 | page = dir_get_page(dir, n); | ||
212 | err = PTR_ERR(page); | ||
213 | if (IS_ERR(page)) | ||
214 | goto out; | ||
215 | lock_page(page); | ||
216 | kaddr = (char*)page_address(page); | ||
217 | dir_end = kaddr + minix_last_byte(dir, n); | ||
218 | de = (minix_dirent *)kaddr; | ||
219 | kaddr += PAGE_CACHE_SIZE - sbi->s_dirsize; | ||
220 | while ((char *)de <= kaddr) { | ||
221 | if ((char *)de == dir_end) { | ||
222 | /* We hit i_size */ | ||
223 | de->inode = 0; | ||
224 | goto got_it; | ||
225 | } | ||
226 | if (!de->inode) | ||
227 | goto got_it; | ||
228 | err = -EEXIST; | ||
229 | if (namecompare(namelen,sbi->s_namelen,name,de->name)) | ||
230 | goto out_unlock; | ||
231 | de = minix_next_entry(de, sbi); | ||
232 | } | ||
233 | unlock_page(page); | ||
234 | dir_put_page(page); | ||
235 | } | ||
236 | BUG(); | ||
237 | return -EINVAL; | ||
238 | |||
239 | got_it: | ||
240 | from = (char*)de - (char*)page_address(page); | ||
241 | to = from + sbi->s_dirsize; | ||
242 | err = page->mapping->a_ops->prepare_write(NULL, page, from, to); | ||
243 | if (err) | ||
244 | goto out_unlock; | ||
245 | memcpy (de->name, name, namelen); | ||
246 | memset (de->name + namelen, 0, sbi->s_dirsize - namelen - 2); | ||
247 | de->inode = inode->i_ino; | ||
248 | err = dir_commit_chunk(page, from, to); | ||
249 | dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC; | ||
250 | mark_inode_dirty(dir); | ||
251 | out_put: | ||
252 | dir_put_page(page); | ||
253 | out: | ||
254 | return err; | ||
255 | out_unlock: | ||
256 | unlock_page(page); | ||
257 | goto out_put; | ||
258 | } | ||
259 | |||
260 | int minix_delete_entry(struct minix_dir_entry *de, struct page *page) | ||
261 | { | ||
262 | struct address_space *mapping = page->mapping; | ||
263 | struct inode *inode = (struct inode*)mapping->host; | ||
264 | char *kaddr = page_address(page); | ||
265 | unsigned from = (char*)de - kaddr; | ||
266 | unsigned to = from + minix_sb(inode->i_sb)->s_dirsize; | ||
267 | int err; | ||
268 | |||
269 | lock_page(page); | ||
270 | err = mapping->a_ops->prepare_write(NULL, page, from, to); | ||
271 | if (err == 0) { | ||
272 | de->inode = 0; | ||
273 | err = dir_commit_chunk(page, from, to); | ||
274 | } else { | ||
275 | unlock_page(page); | ||
276 | } | ||
277 | dir_put_page(page); | ||
278 | inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC; | ||
279 | mark_inode_dirty(inode); | ||
280 | return err; | ||
281 | } | ||
282 | |||
283 | int minix_make_empty(struct inode *inode, struct inode *dir) | ||
284 | { | ||
285 | struct address_space *mapping = inode->i_mapping; | ||
286 | struct page *page = grab_cache_page(mapping, 0); | ||
287 | struct minix_sb_info * sbi = minix_sb(inode->i_sb); | ||
288 | struct minix_dir_entry * de; | ||
289 | char *kaddr; | ||
290 | int err; | ||
291 | |||
292 | if (!page) | ||
293 | return -ENOMEM; | ||
294 | err = mapping->a_ops->prepare_write(NULL, page, 0, 2 * sbi->s_dirsize); | ||
295 | if (err) { | ||
296 | unlock_page(page); | ||
297 | goto fail; | ||
298 | } | ||
299 | |||
300 | kaddr = kmap_atomic(page, KM_USER0); | ||
301 | memset(kaddr, 0, PAGE_CACHE_SIZE); | ||
302 | |||
303 | de = (struct minix_dir_entry *)kaddr; | ||
304 | de->inode = inode->i_ino; | ||
305 | strcpy(de->name,"."); | ||
306 | de = minix_next_entry(de, sbi); | ||
307 | de->inode = dir->i_ino; | ||
308 | strcpy(de->name,".."); | ||
309 | kunmap_atomic(kaddr, KM_USER0); | ||
310 | |||
311 | err = dir_commit_chunk(page, 0, 2 * sbi->s_dirsize); | ||
312 | fail: | ||
313 | page_cache_release(page); | ||
314 | return err; | ||
315 | } | ||
316 | |||
317 | /* | ||
318 | * routine to check that the specified directory is empty (for rmdir) | ||
319 | */ | ||
320 | int minix_empty_dir(struct inode * inode) | ||
321 | { | ||
322 | struct page *page = NULL; | ||
323 | unsigned long i, npages = dir_pages(inode); | ||
324 | struct minix_sb_info *sbi = minix_sb(inode->i_sb); | ||
325 | |||
326 | for (i = 0; i < npages; i++) { | ||
327 | char *kaddr; | ||
328 | minix_dirent * de; | ||
329 | page = dir_get_page(inode, i); | ||
330 | |||
331 | if (IS_ERR(page)) | ||
332 | continue; | ||
333 | |||
334 | kaddr = (char *)page_address(page); | ||
335 | de = (minix_dirent *)kaddr; | ||
336 | kaddr += minix_last_byte(inode, i) - sbi->s_dirsize; | ||
337 | |||
338 | while ((char *)de <= kaddr) { | ||
339 | if (de->inode != 0) { | ||
340 | /* check for . and .. */ | ||
341 | if (de->name[0] != '.') | ||
342 | goto not_empty; | ||
343 | if (!de->name[1]) { | ||
344 | if (de->inode != inode->i_ino) | ||
345 | goto not_empty; | ||
346 | } else if (de->name[1] != '.') | ||
347 | goto not_empty; | ||
348 | else if (de->name[2]) | ||
349 | goto not_empty; | ||
350 | } | ||
351 | de = minix_next_entry(de, sbi); | ||
352 | } | ||
353 | dir_put_page(page); | ||
354 | } | ||
355 | return 1; | ||
356 | |||
357 | not_empty: | ||
358 | dir_put_page(page); | ||
359 | return 0; | ||
360 | } | ||
361 | |||
362 | /* Releases the page */ | ||
363 | void minix_set_link(struct minix_dir_entry *de, struct page *page, | ||
364 | struct inode *inode) | ||
365 | { | ||
366 | struct inode *dir = (struct inode*)page->mapping->host; | ||
367 | struct minix_sb_info *sbi = minix_sb(dir->i_sb); | ||
368 | unsigned from = (char *)de-(char*)page_address(page); | ||
369 | unsigned to = from + sbi->s_dirsize; | ||
370 | int err; | ||
371 | |||
372 | lock_page(page); | ||
373 | err = page->mapping->a_ops->prepare_write(NULL, page, from, to); | ||
374 | if (err == 0) { | ||
375 | de->inode = inode->i_ino; | ||
376 | err = dir_commit_chunk(page, from, to); | ||
377 | } else { | ||
378 | unlock_page(page); | ||
379 | } | ||
380 | dir_put_page(page); | ||
381 | dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC; | ||
382 | mark_inode_dirty(dir); | ||
383 | } | ||
384 | |||
385 | struct minix_dir_entry * minix_dotdot (struct inode *dir, struct page **p) | ||
386 | { | ||
387 | struct page *page = dir_get_page(dir, 0); | ||
388 | struct minix_sb_info *sbi = minix_sb(dir->i_sb); | ||
389 | struct minix_dir_entry *de = NULL; | ||
390 | |||
391 | if (!IS_ERR(page)) { | ||
392 | de = minix_next_entry(page_address(page), sbi); | ||
393 | *p = page; | ||
394 | } | ||
395 | return de; | ||
396 | } | ||
397 | |||
398 | ino_t minix_inode_by_name(struct dentry *dentry) | ||
399 | { | ||
400 | struct page *page; | ||
401 | struct minix_dir_entry *de = minix_find_entry(dentry, &page); | ||
402 | ino_t res = 0; | ||
403 | |||
404 | if (de) { | ||
405 | res = de->inode; | ||
406 | dir_put_page(page); | ||
407 | } | ||
408 | return res; | ||
409 | } | ||