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7#include <linux/fs.h>
8#include <linux/ctype.h>
9#include <linux/buffer_head.h>
10#include "omfs.h"
11
12static int omfs_hash(const char *name, int namelen, int mod)
13{
14 int i, hash = 0;
15 for (i = 0; i < namelen; i++)
16 hash ^= tolower(name[i]) << (i % 24);
17 return hash % mod;
18}
19
20
21
22
23
24static struct buffer_head *omfs_get_bucket(struct inode *dir,
25 const char *name, int namelen, int *ofs)
26{
27 int nbuckets = (dir->i_size - OMFS_DIR_START)/8;
28 int bucket = omfs_hash(name, namelen, nbuckets);
29
30 *ofs = OMFS_DIR_START + bucket * 8;
31 return omfs_bread(dir->i_sb, dir->i_ino);
32}
33
34static struct buffer_head *omfs_scan_list(struct inode *dir, u64 block,
35 const char *name, int namelen,
36 u64 *prev_block)
37{
38 struct buffer_head *bh;
39 struct omfs_inode *oi;
40 int err = -ENOENT;
41 *prev_block = ~0;
42
43 while (block != ~0) {
44 bh = omfs_bread(dir->i_sb, block);
45 if (!bh) {
46 err = -EIO;
47 goto err;
48 }
49
50 oi = (struct omfs_inode *) bh->b_data;
51 if (omfs_is_bad(OMFS_SB(dir->i_sb), &oi->i_head, block)) {
52 brelse(bh);
53 goto err;
54 }
55
56 if (strncmp(oi->i_name, name, namelen) == 0)
57 return bh;
58
59 *prev_block = block;
60 block = be64_to_cpu(oi->i_sibling);
61 brelse(bh);
62 }
63err:
64 return ERR_PTR(err);
65}
66
67static struct buffer_head *omfs_find_entry(struct inode *dir,
68 const char *name, int namelen)
69{
70 struct buffer_head *bh;
71 int ofs;
72 u64 block, dummy;
73
74 bh = omfs_get_bucket(dir, name, namelen, &ofs);
75 if (!bh)
76 return ERR_PTR(-EIO);
77
78 block = be64_to_cpu(*((__be64 *) &bh->b_data[ofs]));
79 brelse(bh);
80
81 return omfs_scan_list(dir, block, name, namelen, &dummy);
82}
83
84int omfs_make_empty(struct inode *inode, struct super_block *sb)
85{
86 struct omfs_sb_info *sbi = OMFS_SB(sb);
87 struct buffer_head *bh;
88 struct omfs_inode *oi;
89
90 bh = omfs_bread(sb, inode->i_ino);
91 if (!bh)
92 return -ENOMEM;
93
94 memset(bh->b_data, 0, sizeof(struct omfs_inode));
95
96 if (S_ISDIR(inode->i_mode)) {
97 memset(&bh->b_data[OMFS_DIR_START], 0xff,
98 sbi->s_sys_blocksize - OMFS_DIR_START);
99 } else
100 omfs_make_empty_table(bh, OMFS_EXTENT_START);
101
102 oi = (struct omfs_inode *) bh->b_data;
103 oi->i_head.h_self = cpu_to_be64(inode->i_ino);
104 oi->i_sibling = ~cpu_to_be64(0ULL);
105
106 mark_buffer_dirty(bh);
107 brelse(bh);
108 return 0;
109}
110
111static int omfs_add_link(struct dentry *dentry, struct inode *inode)
112{
113 struct inode *dir = d_inode(dentry->d_parent);
114 const char *name = dentry->d_name.name;
115 int namelen = dentry->d_name.len;
116 struct omfs_inode *oi;
117 struct buffer_head *bh;
118 u64 block;
119 __be64 *entry;
120 int ofs;
121
122
123 bh = omfs_get_bucket(dir, name, namelen, &ofs);
124 if (!bh)
125 goto out;
126
127 entry = (__be64 *) &bh->b_data[ofs];
128 block = be64_to_cpu(*entry);
129 *entry = cpu_to_be64(inode->i_ino);
130 mark_buffer_dirty(bh);
131 brelse(bh);
132
133
134 bh = omfs_bread(dir->i_sb, inode->i_ino);
135 if (!bh)
136 goto out;
137
138 oi = (struct omfs_inode *) bh->b_data;
139 memcpy(oi->i_name, name, namelen);
140 memset(oi->i_name + namelen, 0, OMFS_NAMELEN - namelen);
141 oi->i_sibling = cpu_to_be64(block);
142 oi->i_parent = cpu_to_be64(dir->i_ino);
143 mark_buffer_dirty(bh);
144 brelse(bh);
145
146 dir->i_ctime = current_time(dir);
147
148
149 mark_inode_dirty(dir);
150 mark_inode_dirty(inode);
151 return 0;
152out:
153 return -ENOMEM;
154}
155
156static int omfs_delete_entry(struct dentry *dentry)
157{
158 struct inode *dir = d_inode(dentry->d_parent);
159 struct inode *dirty;
160 const char *name = dentry->d_name.name;
161 int namelen = dentry->d_name.len;
162 struct omfs_inode *oi;
163 struct buffer_head *bh, *bh2;
164 __be64 *entry, next;
165 u64 block, prev;
166 int ofs;
167 int err = -ENOMEM;
168
169
170 bh = omfs_get_bucket(dir, name, namelen, &ofs);
171 if (!bh)
172 goto out;
173
174 entry = (__be64 *) &bh->b_data[ofs];
175 block = be64_to_cpu(*entry);
176
177 bh2 = omfs_scan_list(dir, block, name, namelen, &prev);
178 if (IS_ERR(bh2)) {
179 err = PTR_ERR(bh2);
180 goto out_free_bh;
181 }
182
183 oi = (struct omfs_inode *) bh2->b_data;
184 next = oi->i_sibling;
185 brelse(bh2);
186
187 if (prev != ~0) {
188
189 brelse(bh);
190 bh = omfs_bread(dir->i_sb, prev);
191 if (!bh)
192 goto out;
193
194 oi = (struct omfs_inode *) bh->b_data;
195 entry = &oi->i_sibling;
196 }
197
198 *entry = next;
199 mark_buffer_dirty(bh);
200
201 if (prev != ~0) {
202 dirty = omfs_iget(dir->i_sb, prev);
203 if (!IS_ERR(dirty)) {
204 mark_inode_dirty(dirty);
205 iput(dirty);
206 }
207 }
208
209 err = 0;
210out_free_bh:
211 brelse(bh);
212out:
213 return err;
214}
215
216static int omfs_dir_is_empty(struct inode *inode)
217{
218 int nbuckets = (inode->i_size - OMFS_DIR_START) / 8;
219 struct buffer_head *bh;
220 u64 *ptr;
221 int i;
222
223 bh = omfs_bread(inode->i_sb, inode->i_ino);
224
225 if (!bh)
226 return 0;
227
228 ptr = (u64 *) &bh->b_data[OMFS_DIR_START];
229
230 for (i = 0; i < nbuckets; i++, ptr++)
231 if (*ptr != ~0)
232 break;
233
234 brelse(bh);
235 return *ptr != ~0;
236}
237
238static int omfs_remove(struct inode *dir, struct dentry *dentry)
239{
240 struct inode *inode = d_inode(dentry);
241 int ret;
242
243
244 if (S_ISDIR(inode->i_mode) &&
245 !omfs_dir_is_empty(inode))
246 return -ENOTEMPTY;
247
248 ret = omfs_delete_entry(dentry);
249 if (ret)
250 return ret;
251
252 clear_nlink(inode);
253 mark_inode_dirty(inode);
254 mark_inode_dirty(dir);
255 return 0;
256}
257
258static int omfs_add_node(struct inode *dir, struct dentry *dentry, umode_t mode)
259{
260 int err;
261 struct inode *inode = omfs_new_inode(dir, mode);
262
263 if (IS_ERR(inode))
264 return PTR_ERR(inode);
265
266 err = omfs_make_empty(inode, dir->i_sb);
267 if (err)
268 goto out_free_inode;
269
270 err = omfs_add_link(dentry, inode);
271 if (err)
272 goto out_free_inode;
273
274 d_instantiate(dentry, inode);
275 return 0;
276
277out_free_inode:
278 iput(inode);
279 return err;
280}
281
282static int omfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
283{
284 return omfs_add_node(dir, dentry, mode | S_IFDIR);
285}
286
287static int omfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
288 bool excl)
289{
290 return omfs_add_node(dir, dentry, mode | S_IFREG);
291}
292
293static struct dentry *omfs_lookup(struct inode *dir, struct dentry *dentry,
294 unsigned int flags)
295{
296 struct buffer_head *bh;
297 struct inode *inode = NULL;
298
299 if (dentry->d_name.len > OMFS_NAMELEN)
300 return ERR_PTR(-ENAMETOOLONG);
301
302 bh = omfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len);
303 if (!IS_ERR(bh)) {
304 struct omfs_inode *oi = (struct omfs_inode *)bh->b_data;
305 ino_t ino = be64_to_cpu(oi->i_head.h_self);
306 brelse(bh);
307 inode = omfs_iget(dir->i_sb, ino);
308 } else if (bh != ERR_PTR(-ENOENT)) {
309 inode = ERR_CAST(bh);
310 }
311 return d_splice_alias(inode, dentry);
312}
313
314
315int omfs_is_bad(struct omfs_sb_info *sbi, struct omfs_header *header,
316 u64 fsblock)
317{
318 int is_bad;
319 u64 ino = be64_to_cpu(header->h_self);
320 is_bad = ((ino != fsblock) || (ino < sbi->s_root_ino) ||
321 (ino > sbi->s_num_blocks));
322
323 if (is_bad)
324 printk(KERN_WARNING "omfs: bad hash chain detected\n");
325
326 return is_bad;
327}
328
329static bool omfs_fill_chain(struct inode *dir, struct dir_context *ctx,
330 u64 fsblock, int hindex)
331{
332
333 while (fsblock != ~0) {
334 struct buffer_head *bh = omfs_bread(dir->i_sb, fsblock);
335 struct omfs_inode *oi;
336 u64 self;
337 unsigned char d_type;
338
339 if (!bh)
340 return true;
341
342 oi = (struct omfs_inode *) bh->b_data;
343 if (omfs_is_bad(OMFS_SB(dir->i_sb), &oi->i_head, fsblock)) {
344 brelse(bh);
345 return true;
346 }
347
348 self = fsblock;
349 fsblock = be64_to_cpu(oi->i_sibling);
350
351
352 if (hindex) {
353 hindex--;
354 brelse(bh);
355 continue;
356 }
357
358 d_type = (oi->i_type == OMFS_DIR) ? DT_DIR : DT_REG;
359
360 if (!dir_emit(ctx, oi->i_name,
361 strnlen(oi->i_name, OMFS_NAMELEN),
362 self, d_type)) {
363 brelse(bh);
364 return false;
365 }
366 brelse(bh);
367 ctx->pos++;
368 }
369 return true;
370}
371
372static int omfs_rename(struct inode *old_dir, struct dentry *old_dentry,
373 struct inode *new_dir, struct dentry *new_dentry,
374 unsigned int flags)
375{
376 struct inode *new_inode = d_inode(new_dentry);
377 struct inode *old_inode = d_inode(old_dentry);
378 int err;
379
380 if (flags & ~RENAME_NOREPLACE)
381 return -EINVAL;
382
383 if (new_inode) {
384
385 err = omfs_remove(new_dir, new_dentry);
386 if (err)
387 goto out;
388 }
389
390
391
392 err = omfs_delete_entry(old_dentry);
393 if (err)
394 goto out;
395
396 mark_inode_dirty(old_dir);
397 err = omfs_add_link(new_dentry, old_inode);
398 if (err)
399 goto out;
400
401 old_inode->i_ctime = current_time(old_inode);
402 mark_inode_dirty(old_inode);
403out:
404 return err;
405}
406
407static int omfs_readdir(struct file *file, struct dir_context *ctx)
408{
409 struct inode *dir = file_inode(file);
410 struct buffer_head *bh;
411 __be64 *p;
412 unsigned int hchain, hindex;
413 int nbuckets;
414
415 if (ctx->pos >> 32)
416 return -EINVAL;
417
418 if (ctx->pos < 1 << 20) {
419 if (!dir_emit_dots(file, ctx))
420 return 0;
421 ctx->pos = 1 << 20;
422 }
423
424 nbuckets = (dir->i_size - OMFS_DIR_START) / 8;
425
426
427 hchain = (ctx->pos >> 20) - 1;
428 hindex = ctx->pos & 0xfffff;
429
430 bh = omfs_bread(dir->i_sb, dir->i_ino);
431 if (!bh)
432 return -EINVAL;
433
434 p = (__be64 *)(bh->b_data + OMFS_DIR_START) + hchain;
435
436 for (; hchain < nbuckets; hchain++) {
437 __u64 fsblock = be64_to_cpu(*p++);
438 if (!omfs_fill_chain(dir, ctx, fsblock, hindex))
439 break;
440 hindex = 0;
441 ctx->pos = (hchain+2) << 20;
442 }
443 brelse(bh);
444 return 0;
445}
446
447const struct inode_operations omfs_dir_inops = {
448 .lookup = omfs_lookup,
449 .mkdir = omfs_mkdir,
450 .rename = omfs_rename,
451 .create = omfs_create,
452 .unlink = omfs_remove,
453 .rmdir = omfs_remove,
454};
455
456const struct file_operations omfs_dir_operations = {
457 .read = generic_read_dir,
458 .iterate_shared = omfs_readdir,
459 .llseek = generic_file_llseek,
460};
461
