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Bob Copelanda3ab7152008-07-25 19:45:16 -07001/*
2 * OMFS (as used by RIO Karma) directory operations.
3 * Copyright (C) 2005 Bob Copeland <me@bobcopeland.com>
4 * Released under GPL v2.
5 */
6
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 * Finds the bucket for a given name and reads the containing block;
22 * *ofs is set to the offset of the first list entry.
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 block = clus_to_blk(OMFS_SB(dir->i_sb), dir->i_ino);
29 int bucket = omfs_hash(name, namelen, nbuckets);
30
31 *ofs = OMFS_DIR_START + bucket * 8;
32 return sb_bread(dir->i_sb, block);
33}
34
35static struct buffer_head *omfs_scan_list(struct inode *dir, u64 block,
36 const char *name, int namelen,
37 u64 *prev_block)
38{
39 struct buffer_head *bh;
40 struct omfs_inode *oi;
41 int err = -ENOENT;
42 *prev_block = ~0;
43
44 while (block != ~0) {
45 bh = sb_bread(dir->i_sb,
46 clus_to_blk(OMFS_SB(dir->i_sb), block));
47 if (!bh) {
48 err = -EIO;
49 goto err;
50 }
51
52 oi = (struct omfs_inode *) bh->b_data;
53 if (omfs_is_bad(OMFS_SB(dir->i_sb), &oi->i_head, block)) {
54 brelse(bh);
55 goto err;
56 }
57
58 if (strncmp(oi->i_name, name, namelen) == 0)
59 return bh;
60
61 *prev_block = block;
62 block = be64_to_cpu(oi->i_sibling);
63 brelse(bh);
64 }
65err:
66 return ERR_PTR(err);
67}
68
69static struct buffer_head *omfs_find_entry(struct inode *dir,
70 const char *name, int namelen)
71{
72 struct buffer_head *bh;
73 int ofs;
74 u64 block, dummy;
75
76 bh = omfs_get_bucket(dir, name, namelen, &ofs);
77 if (!bh)
78 return ERR_PTR(-EIO);
79
80 block = be64_to_cpu(*((__be64 *) &bh->b_data[ofs]));
81 brelse(bh);
82
83 return omfs_scan_list(dir, block, name, namelen, &dummy);
84}
85
86int omfs_make_empty(struct inode *inode, struct super_block *sb)
87{
88 struct omfs_sb_info *sbi = OMFS_SB(sb);
89 int block = clus_to_blk(sbi, inode->i_ino);
90 struct buffer_head *bh;
91 struct omfs_inode *oi;
92
93 bh = sb_bread(sb, block);
94 if (!bh)
95 return -ENOMEM;
96
97 memset(bh->b_data, 0, sizeof(struct omfs_inode));
98
99 if (inode->i_mode & S_IFDIR) {
100 memset(&bh->b_data[OMFS_DIR_START], 0xff,
101 sbi->s_sys_blocksize - OMFS_DIR_START);
102 } else
103 omfs_make_empty_table(bh, OMFS_EXTENT_START);
104
105 oi = (struct omfs_inode *) bh->b_data;
106 oi->i_head.h_self = cpu_to_be64(inode->i_ino);
Harvey Harrisond406f662008-07-29 22:33:46 -0700107 oi->i_sibling = ~cpu_to_be64(0ULL);
Bob Copelanda3ab7152008-07-25 19:45:16 -0700108
109 mark_buffer_dirty(bh);
110 brelse(bh);
111 return 0;
112}
113
114static int omfs_add_link(struct dentry *dentry, struct inode *inode)
115{
116 struct inode *dir = dentry->d_parent->d_inode;
117 const char *name = dentry->d_name.name;
118 int namelen = dentry->d_name.len;
119 struct omfs_inode *oi;
120 struct buffer_head *bh;
121 u64 block;
122 __be64 *entry;
123 int ofs;
124
125 /* just prepend to head of queue in proper bucket */
126 bh = omfs_get_bucket(dir, name, namelen, &ofs);
127 if (!bh)
128 goto out;
129
130 entry = (__be64 *) &bh->b_data[ofs];
131 block = be64_to_cpu(*entry);
132 *entry = cpu_to_be64(inode->i_ino);
133 mark_buffer_dirty(bh);
134 brelse(bh);
135
136 /* now set the sibling and parent pointers on the new inode */
137 bh = sb_bread(dir->i_sb, clus_to_blk(OMFS_SB(dir->i_sb), inode->i_ino));
138 if (!bh)
139 goto out;
140
141 oi = (struct omfs_inode *) bh->b_data;
142 memcpy(oi->i_name, name, namelen);
143 memset(oi->i_name + namelen, 0, OMFS_NAMELEN - namelen);
144 oi->i_sibling = cpu_to_be64(block);
145 oi->i_parent = cpu_to_be64(dir->i_ino);
146 mark_buffer_dirty(bh);
147 brelse(bh);
148
149 dir->i_ctime = CURRENT_TIME_SEC;
150
151 /* mark affected inodes dirty to rebuild checksums */
152 mark_inode_dirty(dir);
153 mark_inode_dirty(inode);
154 return 0;
155out:
156 return -ENOMEM;
157}
158
159static int omfs_delete_entry(struct dentry *dentry)
160{
161 struct inode *dir = dentry->d_parent->d_inode;
162 struct inode *dirty;
163 const char *name = dentry->d_name.name;
164 int namelen = dentry->d_name.len;
165 struct omfs_inode *oi;
166 struct buffer_head *bh, *bh2;
167 __be64 *entry, next;
168 u64 block, prev;
169 int ofs;
170 int err = -ENOMEM;
171
172 /* delete the proper node in the bucket's linked list */
173 bh = omfs_get_bucket(dir, name, namelen, &ofs);
174 if (!bh)
175 goto out;
176
177 entry = (__be64 *) &bh->b_data[ofs];
178 block = be64_to_cpu(*entry);
179
180 bh2 = omfs_scan_list(dir, block, name, namelen, &prev);
181 if (IS_ERR(bh2)) {
182 err = PTR_ERR(bh2);
183 goto out_free_bh;
184 }
185
186 oi = (struct omfs_inode *) bh2->b_data;
187 next = oi->i_sibling;
188 brelse(bh2);
189
190 if (prev != ~0) {
191 /* found in middle of list, get list ptr */
192 brelse(bh);
193 bh = sb_bread(dir->i_sb,
194 clus_to_blk(OMFS_SB(dir->i_sb), prev));
195 if (!bh)
196 goto out;
197
198 oi = (struct omfs_inode *) bh->b_data;
199 entry = &oi->i_sibling;
200 }
201
202 *entry = next;
203 mark_buffer_dirty(bh);
204
205 if (prev != ~0) {
206 dirty = omfs_iget(dir->i_sb, prev);
207 if (!IS_ERR(dirty)) {
208 mark_inode_dirty(dirty);
209 iput(dirty);
210 }
211 }
212
213 err = 0;
214out_free_bh:
215 brelse(bh);
216out:
217 return err;
218}
219
220static int omfs_dir_is_empty(struct inode *inode)
221{
222 int nbuckets = (inode->i_size - OMFS_DIR_START) / 8;
223 struct buffer_head *bh;
224 u64 *ptr;
225 int i;
226
227 bh = sb_bread(inode->i_sb, clus_to_blk(OMFS_SB(inode->i_sb),
228 inode->i_ino));
229
230 if (!bh)
231 return 0;
232
233 ptr = (u64 *) &bh->b_data[OMFS_DIR_START];
234
235 for (i = 0; i < nbuckets; i++, ptr++)
236 if (*ptr != ~0)
237 break;
238
239 brelse(bh);
240 return *ptr != ~0;
241}
242
243static int omfs_unlink(struct inode *dir, struct dentry *dentry)
244{
245 int ret;
246 struct inode *inode = dentry->d_inode;
247
248 ret = omfs_delete_entry(dentry);
249 if (ret)
250 goto end_unlink;
251
252 inode_dec_link_count(inode);
253 mark_inode_dirty(dir);
254
255end_unlink:
256 return ret;
257}
258
259static int omfs_rmdir(struct inode *dir, struct dentry *dentry)
260{
261 int err = -ENOTEMPTY;
262 struct inode *inode = dentry->d_inode;
263
264 if (omfs_dir_is_empty(inode)) {
265 err = omfs_unlink(dir, dentry);
266 if (!err)
267 inode_dec_link_count(inode);
268 }
269 return err;
270}
271
272static int omfs_add_node(struct inode *dir, struct dentry *dentry, int mode)
273{
274 int err;
275 struct inode *inode = omfs_new_inode(dir, mode);
276
277 if (IS_ERR(inode))
278 return PTR_ERR(inode);
279
280 err = omfs_make_empty(inode, dir->i_sb);
281 if (err)
282 goto out_free_inode;
283
284 err = omfs_add_link(dentry, inode);
285 if (err)
286 goto out_free_inode;
287
288 d_instantiate(dentry, inode);
289 return 0;
290
291out_free_inode:
292 iput(inode);
293 return err;
294}
295
296static int omfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
297{
298 return omfs_add_node(dir, dentry, mode | S_IFDIR);
299}
300
301static int omfs_create(struct inode *dir, struct dentry *dentry, int mode,
302 struct nameidata *nd)
303{
304 return omfs_add_node(dir, dentry, mode | S_IFREG);
305}
306
307static struct dentry *omfs_lookup(struct inode *dir, struct dentry *dentry,
308 struct nameidata *nd)
309{
310 struct buffer_head *bh;
311 struct inode *inode = NULL;
312
313 if (dentry->d_name.len > OMFS_NAMELEN)
314 return ERR_PTR(-ENAMETOOLONG);
315
316 bh = omfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len);
317 if (!IS_ERR(bh)) {
318 struct omfs_inode *oi = (struct omfs_inode *)bh->b_data;
319 ino_t ino = be64_to_cpu(oi->i_head.h_self);
320 brelse(bh);
321 inode = omfs_iget(dir->i_sb, ino);
322 if (IS_ERR(inode))
323 return ERR_CAST(inode);
324 }
325 d_add(dentry, inode);
326 return NULL;
327}
328
329/* sanity check block's self pointer */
330int omfs_is_bad(struct omfs_sb_info *sbi, struct omfs_header *header,
331 u64 fsblock)
332{
333 int is_bad;
334 u64 ino = be64_to_cpu(header->h_self);
335 is_bad = ((ino != fsblock) || (ino < sbi->s_root_ino) ||
336 (ino > sbi->s_num_blocks));
337
338 if (is_bad)
339 printk(KERN_WARNING "omfs: bad hash chain detected\n");
340
341 return is_bad;
342}
343
344static int omfs_fill_chain(struct file *filp, void *dirent, filldir_t filldir,
345 u64 fsblock, int hindex)
346{
347 struct inode *dir = filp->f_dentry->d_inode;
348 struct buffer_head *bh;
349 struct omfs_inode *oi;
350 u64 self;
351 int res = 0;
352 unsigned char d_type;
353
354 /* follow chain in this bucket */
355 while (fsblock != ~0) {
356 bh = sb_bread(dir->i_sb, clus_to_blk(OMFS_SB(dir->i_sb),
357 fsblock));
358 if (!bh)
359 goto out;
360
361 oi = (struct omfs_inode *) bh->b_data;
362 if (omfs_is_bad(OMFS_SB(dir->i_sb), &oi->i_head, fsblock)) {
363 brelse(bh);
364 goto out;
365 }
366
367 self = fsblock;
368 fsblock = be64_to_cpu(oi->i_sibling);
369
370 /* skip visited nodes */
371 if (hindex) {
372 hindex--;
373 brelse(bh);
374 continue;
375 }
376
377 d_type = (oi->i_type == OMFS_DIR) ? DT_DIR : DT_REG;
378
379 res = filldir(dirent, oi->i_name, strnlen(oi->i_name,
380 OMFS_NAMELEN), filp->f_pos, self, d_type);
381 if (res == 0)
382 filp->f_pos++;
383 brelse(bh);
384 }
385out:
386 return res;
387}
388
389static int omfs_rename(struct inode *old_dir, struct dentry *old_dentry,
390 struct inode *new_dir, struct dentry *new_dentry)
391{
392 struct inode *new_inode = new_dentry->d_inode;
393 struct inode *old_inode = old_dentry->d_inode;
394 struct buffer_head *bh;
395 int is_dir;
396 int err;
397
398 is_dir = S_ISDIR(old_inode->i_mode);
399
400 if (new_inode) {
401 /* overwriting existing file/dir */
402 err = -ENOTEMPTY;
403 if (is_dir && !omfs_dir_is_empty(new_inode))
404 goto out;
405
406 err = -ENOENT;
407 bh = omfs_find_entry(new_dir, new_dentry->d_name.name,
408 new_dentry->d_name.len);
409 if (IS_ERR(bh))
410 goto out;
411 brelse(bh);
412
413 err = omfs_unlink(new_dir, new_dentry);
414 if (err)
415 goto out;
416 }
417
418 /* since omfs locates files by name, we need to unlink _before_
419 * adding the new link or we won't find the old one */
420 inode_inc_link_count(old_inode);
421 err = omfs_unlink(old_dir, old_dentry);
422 if (err) {
423 inode_dec_link_count(old_inode);
424 goto out;
425 }
426
427 err = omfs_add_link(new_dentry, old_inode);
428 if (err)
429 goto out;
430
431 old_inode->i_ctime = CURRENT_TIME_SEC;
432out:
433 return err;
434}
435
436static int omfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
437{
438 struct inode *dir = filp->f_dentry->d_inode;
439 struct buffer_head *bh;
440 loff_t offset, res;
441 unsigned int hchain, hindex;
442 int nbuckets;
443 u64 fsblock;
444 int ret = -EINVAL;
445
446 if (filp->f_pos >> 32)
447 goto success;
448
449 switch ((unsigned long) filp->f_pos) {
450 case 0:
451 if (filldir(dirent, ".", 1, 0, dir->i_ino, DT_DIR) < 0)
452 goto success;
453 filp->f_pos++;
454 /* fall through */
455 case 1:
456 if (filldir(dirent, "..", 2, 1,
457 parent_ino(filp->f_dentry), DT_DIR) < 0)
458 goto success;
459 filp->f_pos = 1 << 20;
460 /* fall through */
461 }
462
463 nbuckets = (dir->i_size - OMFS_DIR_START) / 8;
464
465 /* high 12 bits store bucket + 1 and low 20 bits store hash index */
466 hchain = (filp->f_pos >> 20) - 1;
467 hindex = filp->f_pos & 0xfffff;
468
469 bh = sb_bread(dir->i_sb, clus_to_blk(OMFS_SB(dir->i_sb), dir->i_ino));
470 if (!bh)
471 goto out;
472
473 offset = OMFS_DIR_START + hchain * 8;
474
475 for (; hchain < nbuckets; hchain++, offset += 8) {
476 fsblock = be64_to_cpu(*((__be64 *) &bh->b_data[offset]));
477
478 res = omfs_fill_chain(filp, dirent, filldir, fsblock, hindex);
479 hindex = 0;
480 if (res < 0)
481 break;
482
483 filp->f_pos = (hchain+2) << 20;
484 }
485 brelse(bh);
486success:
487 ret = 0;
488out:
489 return ret;
490}
491
492struct inode_operations omfs_dir_inops = {
493 .lookup = omfs_lookup,
494 .mkdir = omfs_mkdir,
495 .rename = omfs_rename,
496 .create = omfs_create,
497 .unlink = omfs_unlink,
498 .rmdir = omfs_rmdir,
499};
500
501struct file_operations omfs_dir_operations = {
502 .read = generic_read_dir,
503 .readdir = omfs_readdir,
Christoph Hellwig3222a3e2008-09-03 21:53:01 +0200504 .llseek = generic_file_llseek,
Bob Copelanda3ab7152008-07-25 19:45:16 -0700505};