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16#include <linux/pagemap.h>
17#include <linux/highmem.h>
18#include <linux/swap.h>
19#include "sysv.h"
20
21static int sysv_readdir(struct file *, void *, filldir_t);
22
23const struct file_operations sysv_dir_operations = {
24 .llseek = generic_file_llseek,
25 .read = generic_read_dir,
26 .readdir = sysv_readdir,
27 .fsync = generic_file_fsync,
28};
29
30static inline void dir_put_page(struct page *page)
31{
32 kunmap(page);
33 page_cache_release(page);
34}
35
36static inline unsigned long dir_pages(struct inode *inode)
37{
38 return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT;
39}
40
41static int dir_commit_chunk(struct page *page, loff_t pos, unsigned len)
42{
43 struct address_space *mapping = page->mapping;
44 struct inode *dir = mapping->host;
45 int err = 0;
46
47 block_write_end(NULL, mapping, pos, len, len, page, NULL);
48 if (pos+len > dir->i_size) {
49 i_size_write(dir, pos+len);
50 mark_inode_dirty(dir);
51 }
52 if (IS_DIRSYNC(dir))
53 err = write_one_page(page, 1);
54 else
55 unlock_page(page);
56 return err;
57}
58
59static struct page * dir_get_page(struct inode *dir, unsigned long n)
60{
61 struct address_space *mapping = dir->i_mapping;
62 struct page *page = read_mapping_page(mapping, n, NULL);
63 if (!IS_ERR(page))
64 kmap(page);
65 return page;
66}
67
68static int sysv_readdir(struct file * filp, void * dirent, filldir_t filldir)
69{
70 unsigned long pos = filp->f_pos;
71 struct inode *inode = file_inode(filp);
72 struct super_block *sb = inode->i_sb;
73 unsigned offset = pos & ~PAGE_CACHE_MASK;
74 unsigned long n = pos >> PAGE_CACHE_SHIFT;
75 unsigned long npages = dir_pages(inode);
76
77 pos = (pos + SYSV_DIRSIZE-1) & ~(SYSV_DIRSIZE-1);
78 if (pos >= inode->i_size)
79 goto done;
80
81 for ( ; n < npages; n++, offset = 0) {
82 char *kaddr, *limit;
83 struct sysv_dir_entry *de;
84 struct page *page = dir_get_page(inode, n);
85
86 if (IS_ERR(page))
87 continue;
88 kaddr = (char *)page_address(page);
89 de = (struct sysv_dir_entry *)(kaddr+offset);
90 limit = kaddr + PAGE_CACHE_SIZE - SYSV_DIRSIZE;
91 for ( ;(char*)de <= limit; de++) {
92 char *name = de->name;
93 int over;
94
95 if (!de->inode)
96 continue;
97
98 offset = (char *)de - kaddr;
99
100 over = filldir(dirent, name, strnlen(name,SYSV_NAMELEN),
101 ((loff_t)n<<PAGE_CACHE_SHIFT) | offset,
102 fs16_to_cpu(SYSV_SB(sb), de->inode),
103 DT_UNKNOWN);
104 if (over) {
105 dir_put_page(page);
106 goto done;
107 }
108 }
109 dir_put_page(page);
110 }
111
112done:
113 filp->f_pos = ((loff_t)n << PAGE_CACHE_SHIFT) | offset;
114 return 0;
115}
116
117
118
119
120static inline int namecompare(int len, int maxlen,
121 const char * name, const char * buffer)
122{
123 if (len < maxlen && buffer[len])
124 return 0;
125 return !memcmp(name, buffer, len);
126}
127
128
129
130
131
132
133
134
135
136struct sysv_dir_entry *sysv_find_entry(struct dentry *dentry, struct page **res_page)
137{
138 const char * name = dentry->d_name.name;
139 int namelen = dentry->d_name.len;
140 struct inode * dir = dentry->d_parent->d_inode;
141 unsigned long start, n;
142 unsigned long npages = dir_pages(dir);
143 struct page *page = NULL;
144 struct sysv_dir_entry *de;
145
146 *res_page = NULL;
147
148 start = SYSV_I(dir)->i_dir_start_lookup;
149 if (start >= npages)
150 start = 0;
151 n = start;
152
153 do {
154 char *kaddr;
155 page = dir_get_page(dir, n);
156 if (!IS_ERR(page)) {
157 kaddr = (char*)page_address(page);
158 de = (struct sysv_dir_entry *) kaddr;
159 kaddr += PAGE_CACHE_SIZE - SYSV_DIRSIZE;
160 for ( ; (char *) de <= kaddr ; de++) {
161 if (!de->inode)
162 continue;
163 if (namecompare(namelen, SYSV_NAMELEN,
164 name, de->name))
165 goto found;
166 }
167 dir_put_page(page);
168 }
169
170 if (++n >= npages)
171 n = 0;
172 } while (n != start);
173
174 return NULL;
175
176found:
177 SYSV_I(dir)->i_dir_start_lookup = n;
178 *res_page = page;
179 return de;
180}
181
182int sysv_add_link(struct dentry *dentry, struct inode *inode)
183{
184 struct inode *dir = dentry->d_parent->d_inode;
185 const char * name = dentry->d_name.name;
186 int namelen = dentry->d_name.len;
187 struct page *page = NULL;
188 struct sysv_dir_entry * de;
189 unsigned long npages = dir_pages(dir);
190 unsigned long n;
191 char *kaddr;
192 loff_t pos;
193 int err;
194
195
196 for (n = 0; n <= npages; n++) {
197 page = dir_get_page(dir, n);
198 err = PTR_ERR(page);
199 if (IS_ERR(page))
200 goto out;
201 kaddr = (char*)page_address(page);
202 de = (struct sysv_dir_entry *)kaddr;
203 kaddr += PAGE_CACHE_SIZE - SYSV_DIRSIZE;
204 while ((char *)de <= kaddr) {
205 if (!de->inode)
206 goto got_it;
207 err = -EEXIST;
208 if (namecompare(namelen, SYSV_NAMELEN, name, de->name))
209 goto out_page;
210 de++;
211 }
212 dir_put_page(page);
213 }
214 BUG();
215 return -EINVAL;
216
217got_it:
218 pos = page_offset(page) +
219 (char*)de - (char*)page_address(page);
220 lock_page(page);
221 err = sysv_prepare_chunk(page, pos, SYSV_DIRSIZE);
222 if (err)
223 goto out_unlock;
224 memcpy (de->name, name, namelen);
225 memset (de->name + namelen, 0, SYSV_DIRSIZE - namelen - 2);
226 de->inode = cpu_to_fs16(SYSV_SB(inode->i_sb), inode->i_ino);
227 err = dir_commit_chunk(page, pos, SYSV_DIRSIZE);
228 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
229 mark_inode_dirty(dir);
230out_page:
231 dir_put_page(page);
232out:
233 return err;
234out_unlock:
235 unlock_page(page);
236 goto out_page;
237}
238
239int sysv_delete_entry(struct sysv_dir_entry *de, struct page *page)
240{
241 struct inode *inode = page->mapping->host;
242 char *kaddr = (char*)page_address(page);
243 loff_t pos = page_offset(page) + (char *)de - kaddr;
244 int err;
245
246 lock_page(page);
247 err = sysv_prepare_chunk(page, pos, SYSV_DIRSIZE);
248 BUG_ON(err);
249 de->inode = 0;
250 err = dir_commit_chunk(page, pos, SYSV_DIRSIZE);
251 dir_put_page(page);
252 inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
253 mark_inode_dirty(inode);
254 return err;
255}
256
257int sysv_make_empty(struct inode *inode, struct inode *dir)
258{
259 struct page *page = grab_cache_page(inode->i_mapping, 0);
260 struct sysv_dir_entry * de;
261 char *base;
262 int err;
263
264 if (!page)
265 return -ENOMEM;
266 err = sysv_prepare_chunk(page, 0, 2 * SYSV_DIRSIZE);
267 if (err) {
268 unlock_page(page);
269 goto fail;
270 }
271 kmap(page);
272
273 base = (char*)page_address(page);
274 memset(base, 0, PAGE_CACHE_SIZE);
275
276 de = (struct sysv_dir_entry *) base;
277 de->inode = cpu_to_fs16(SYSV_SB(inode->i_sb), inode->i_ino);
278 strcpy(de->name,".");
279 de++;
280 de->inode = cpu_to_fs16(SYSV_SB(inode->i_sb), dir->i_ino);
281 strcpy(de->name,"..");
282
283 kunmap(page);
284 err = dir_commit_chunk(page, 0, 2 * SYSV_DIRSIZE);
285fail:
286 page_cache_release(page);
287 return err;
288}
289
290
291
292
293int sysv_empty_dir(struct inode * inode)
294{
295 struct super_block *sb = inode->i_sb;
296 struct page *page = NULL;
297 unsigned long i, npages = dir_pages(inode);
298
299 for (i = 0; i < npages; i++) {
300 char *kaddr;
301 struct sysv_dir_entry * de;
302 page = dir_get_page(inode, i);
303
304 if (IS_ERR(page))
305 continue;
306
307 kaddr = (char *)page_address(page);
308 de = (struct sysv_dir_entry *)kaddr;
309 kaddr += PAGE_CACHE_SIZE-SYSV_DIRSIZE;
310
311 for ( ;(char *)de <= kaddr; de++) {
312 if (!de->inode)
313 continue;
314
315 if (de->name[0] != '.')
316 goto not_empty;
317 if (!de->name[1]) {
318 if (de->inode == cpu_to_fs16(SYSV_SB(sb),
319 inode->i_ino))
320 continue;
321 goto not_empty;
322 }
323 if (de->name[1] != '.' || de->name[2])
324 goto not_empty;
325 }
326 dir_put_page(page);
327 }
328 return 1;
329
330not_empty:
331 dir_put_page(page);
332 return 0;
333}
334
335
336void sysv_set_link(struct sysv_dir_entry *de, struct page *page,
337 struct inode *inode)
338{
339 struct inode *dir = page->mapping->host;
340 loff_t pos = page_offset(page) +
341 (char *)de-(char*)page_address(page);
342 int err;
343
344 lock_page(page);
345 err = sysv_prepare_chunk(page, pos, SYSV_DIRSIZE);
346 BUG_ON(err);
347 de->inode = cpu_to_fs16(SYSV_SB(inode->i_sb), inode->i_ino);
348 err = dir_commit_chunk(page, pos, SYSV_DIRSIZE);
349 dir_put_page(page);
350 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
351 mark_inode_dirty(dir);
352}
353
354struct sysv_dir_entry * sysv_dotdot (struct inode *dir, struct page **p)
355{
356 struct page *page = dir_get_page(dir, 0);
357 struct sysv_dir_entry *de = NULL;
358
359 if (!IS_ERR(page)) {
360 de = (struct sysv_dir_entry*) page_address(page) + 1;
361 *p = page;
362 }
363 return de;
364}
365
366ino_t sysv_inode_by_name(struct dentry *dentry)
367{
368 struct page *page;
369 struct sysv_dir_entry *de = sysv_find_entry (dentry, &page);
370 ino_t res = 0;
371
372 if (de) {
373 res = fs16_to_cpu(SYSV_SB(dentry->d_sb), de->inode);
374 dir_put_page(page);
375 }
376 return res;
377}
378
