[PATCH] fix ->llseek for more directories
[linux-2.6.git] / fs / bfs / dir.c
1 /*
2  *      fs/bfs/dir.c
3  *      BFS directory operations.
4  *      Copyright (C) 1999,2000  Tigran Aivazian <tigran@veritas.com>
5  *      Made endianness-clean by Andrew Stribblehill <ads@wompom.org> 2005
6  */
7
8 #include <linux/time.h>
9 #include <linux/string.h>
10 #include <linux/fs.h>
11 #include <linux/smp_lock.h>
12 #include <linux/buffer_head.h>
13 #include <linux/sched.h>
14 #include "bfs.h"
15
16 #undef DEBUG
17
18 #ifdef DEBUG
19 #define dprintf(x...)   printf(x)
20 #else
21 #define dprintf(x...)
22 #endif
23
24 static int bfs_add_entry(struct inode *dir, const unsigned char *name,
25                                                 int namelen, int ino);
26 static struct buffer_head *bfs_find_entry(struct inode *dir,
27                                 const unsigned char *name, int namelen,
28                                 struct bfs_dirent **res_dir);
29
30 static int bfs_readdir(struct file *f, void *dirent, filldir_t filldir)
31 {
32         struct inode *dir = f->f_path.dentry->d_inode;
33         struct buffer_head *bh;
34         struct bfs_dirent *de;
35         struct bfs_sb_info *info = BFS_SB(dir->i_sb);
36         unsigned int offset;
37         int block;
38
39         mutex_lock(&info->bfs_lock);
40
41         if (f->f_pos & (BFS_DIRENT_SIZE - 1)) {
42                 printf("Bad f_pos=%08lx for %s:%08lx\n",
43                                         (unsigned long)f->f_pos,
44                                         dir->i_sb->s_id, dir->i_ino);
45                 mutex_unlock(&info->bfs_lock);
46                 return -EBADF;
47         }
48
49         while (f->f_pos < dir->i_size) {
50                 offset = f->f_pos & (BFS_BSIZE - 1);
51                 block = BFS_I(dir)->i_sblock + (f->f_pos >> BFS_BSIZE_BITS);
52                 bh = sb_bread(dir->i_sb, block);
53                 if (!bh) {
54                         f->f_pos += BFS_BSIZE - offset;
55                         continue;
56                 }
57                 do {
58                         de = (struct bfs_dirent *)(bh->b_data + offset);
59                         if (de->ino) {
60                                 int size = strnlen(de->name, BFS_NAMELEN);
61                                 if (filldir(dirent, de->name, size, f->f_pos,
62                                                 le16_to_cpu(de->ino),
63                                                 DT_UNKNOWN) < 0) {
64                                         brelse(bh);
65                                         mutex_unlock(&info->bfs_lock);
66                                         return 0;
67                                 }
68                         }
69                         offset += BFS_DIRENT_SIZE;
70                         f->f_pos += BFS_DIRENT_SIZE;
71                 } while ((offset < BFS_BSIZE) && (f->f_pos < dir->i_size));
72                 brelse(bh);
73         }
74
75         mutex_unlock(&info->bfs_lock);
76         return 0;       
77 }
78
79 const struct file_operations bfs_dir_operations = {
80         .read           = generic_read_dir,
81         .readdir        = bfs_readdir,
82         .fsync          = file_fsync,
83         .llseek         = generic_file_llseek,
84 };
85
86 extern void dump_imap(const char *, struct super_block *);
87
88 static int bfs_create(struct inode *dir, struct dentry *dentry, int mode,
89                                                 struct nameidata *nd)
90 {
91         int err;
92         struct inode *inode;
93         struct super_block *s = dir->i_sb;
94         struct bfs_sb_info *info = BFS_SB(s);
95         unsigned long ino;
96
97         inode = new_inode(s);
98         if (!inode)
99                 return -ENOSPC;
100         mutex_lock(&info->bfs_lock);
101         ino = find_first_zero_bit(info->si_imap, info->si_lasti);
102         if (ino > info->si_lasti) {
103                 mutex_unlock(&info->bfs_lock);
104                 iput(inode);
105                 return -ENOSPC;
106         }
107         set_bit(ino, info->si_imap);
108         info->si_freei--;
109         inode->i_uid = current->fsuid;
110         inode->i_gid = (dir->i_mode & S_ISGID) ? dir->i_gid : current->fsgid;
111         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
112         inode->i_blocks = 0;
113         inode->i_op = &bfs_file_inops;
114         inode->i_fop = &bfs_file_operations;
115         inode->i_mapping->a_ops = &bfs_aops;
116         inode->i_mode = mode;
117         inode->i_ino = ino;
118         BFS_I(inode)->i_dsk_ino = ino;
119         BFS_I(inode)->i_sblock = 0;
120         BFS_I(inode)->i_eblock = 0;
121         insert_inode_hash(inode);
122         mark_inode_dirty(inode);
123         dump_imap("create", s);
124
125         err = bfs_add_entry(dir, dentry->d_name.name, dentry->d_name.len,
126                                                         inode->i_ino);
127         if (err) {
128                 inode_dec_link_count(inode);
129                 mutex_unlock(&info->bfs_lock);
130                 iput(inode);
131                 return err;
132         }
133         mutex_unlock(&info->bfs_lock);
134         d_instantiate(dentry, inode);
135         return 0;
136 }
137
138 static struct dentry *bfs_lookup(struct inode *dir, struct dentry *dentry,
139                                                 struct nameidata *nd)
140 {
141         struct inode *inode = NULL;
142         struct buffer_head *bh;
143         struct bfs_dirent *de;
144         struct bfs_sb_info *info = BFS_SB(dir->i_sb);
145
146         if (dentry->d_name.len > BFS_NAMELEN)
147                 return ERR_PTR(-ENAMETOOLONG);
148
149         mutex_lock(&info->bfs_lock);
150         bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
151         if (bh) {
152                 unsigned long ino = (unsigned long)le16_to_cpu(de->ino);
153                 brelse(bh);
154                 inode = bfs_iget(dir->i_sb, ino);
155                 if (IS_ERR(inode)) {
156                         mutex_unlock(&info->bfs_lock);
157                         return ERR_CAST(inode);
158                 }
159         }
160         mutex_unlock(&info->bfs_lock);
161         d_add(dentry, inode);
162         return NULL;
163 }
164
165 static int bfs_link(struct dentry *old, struct inode *dir,
166                                                 struct dentry *new)
167 {
168         struct inode *inode = old->d_inode;
169         struct bfs_sb_info *info = BFS_SB(inode->i_sb);
170         int err;
171
172         mutex_lock(&info->bfs_lock);
173         err = bfs_add_entry(dir, new->d_name.name, new->d_name.len,
174                                                         inode->i_ino);
175         if (err) {
176                 mutex_unlock(&info->bfs_lock);
177                 return err;
178         }
179         inc_nlink(inode);
180         inode->i_ctime = CURRENT_TIME_SEC;
181         mark_inode_dirty(inode);
182         atomic_inc(&inode->i_count);
183         d_instantiate(new, inode);
184         mutex_unlock(&info->bfs_lock);
185         return 0;
186 }
187
188 static int bfs_unlink(struct inode *dir, struct dentry *dentry)
189 {
190         int error = -ENOENT;
191         struct inode *inode = dentry->d_inode;
192         struct buffer_head *bh;
193         struct bfs_dirent *de;
194         struct bfs_sb_info *info = BFS_SB(inode->i_sb);
195
196         mutex_lock(&info->bfs_lock);
197         bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
198         if (!bh || (le16_to_cpu(de->ino) != inode->i_ino))
199                 goto out_brelse;
200
201         if (!inode->i_nlink) {
202                 printf("unlinking non-existent file %s:%lu (nlink=%d)\n",
203                                         inode->i_sb->s_id, inode->i_ino,
204                                         inode->i_nlink);
205                 inode->i_nlink = 1;
206         }
207         de->ino = 0;
208         mark_buffer_dirty(bh);
209         dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
210         mark_inode_dirty(dir);
211         inode->i_ctime = dir->i_ctime;
212         inode_dec_link_count(inode);
213         error = 0;
214
215 out_brelse:
216         brelse(bh);
217         mutex_unlock(&info->bfs_lock);
218         return error;
219 }
220
221 static int bfs_rename(struct inode *old_dir, struct dentry *old_dentry,
222                         struct inode *new_dir, struct dentry *new_dentry)
223 {
224         struct inode *old_inode, *new_inode;
225         struct buffer_head *old_bh, *new_bh;
226         struct bfs_dirent *old_de, *new_de;
227         struct bfs_sb_info *info;
228         int error = -ENOENT;
229
230         old_bh = new_bh = NULL;
231         old_inode = old_dentry->d_inode;
232         if (S_ISDIR(old_inode->i_mode))
233                 return -EINVAL;
234
235         info = BFS_SB(old_inode->i_sb);
236
237         mutex_lock(&info->bfs_lock);
238         old_bh = bfs_find_entry(old_dir, 
239                                 old_dentry->d_name.name, 
240                                 old_dentry->d_name.len, &old_de);
241
242         if (!old_bh || (le16_to_cpu(old_de->ino) != old_inode->i_ino))
243                 goto end_rename;
244
245         error = -EPERM;
246         new_inode = new_dentry->d_inode;
247         new_bh = bfs_find_entry(new_dir, 
248                                 new_dentry->d_name.name, 
249                                 new_dentry->d_name.len, &new_de);
250
251         if (new_bh && !new_inode) {
252                 brelse(new_bh);
253                 new_bh = NULL;
254         }
255         if (!new_bh) {
256                 error = bfs_add_entry(new_dir, 
257                                         new_dentry->d_name.name,
258                                         new_dentry->d_name.len,
259                                         old_inode->i_ino);
260                 if (error)
261                         goto end_rename;
262         }
263         old_de->ino = 0;
264         old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
265         mark_inode_dirty(old_dir);
266         if (new_inode) {
267                 new_inode->i_ctime = CURRENT_TIME_SEC;
268                 inode_dec_link_count(new_inode);
269         }
270         mark_buffer_dirty(old_bh);
271         error = 0;
272
273 end_rename:
274         mutex_unlock(&info->bfs_lock);
275         brelse(old_bh);
276         brelse(new_bh);
277         return error;
278 }
279
280 const struct inode_operations bfs_dir_inops = {
281         .create                 = bfs_create,
282         .lookup                 = bfs_lookup,
283         .link                   = bfs_link,
284         .unlink                 = bfs_unlink,
285         .rename                 = bfs_rename,
286 };
287
288 static int bfs_add_entry(struct inode *dir, const unsigned char *name,
289                                                         int namelen, int ino)
290 {
291         struct buffer_head *bh;
292         struct bfs_dirent *de;
293         int block, sblock, eblock, off, pos;
294         int i;
295
296         dprintf("name=%s, namelen=%d\n", name, namelen);
297
298         if (!namelen)
299                 return -ENOENT;
300         if (namelen > BFS_NAMELEN)
301                 return -ENAMETOOLONG;
302
303         sblock = BFS_I(dir)->i_sblock;
304         eblock = BFS_I(dir)->i_eblock;
305         for (block = sblock; block <= eblock; block++) {
306                 bh = sb_bread(dir->i_sb, block);
307                 if (!bh)
308                         return -ENOSPC;
309                 for (off = 0; off < BFS_BSIZE; off += BFS_DIRENT_SIZE) {
310                         de = (struct bfs_dirent *)(bh->b_data + off);
311                         if (!de->ino) {
312                                 pos = (block - sblock) * BFS_BSIZE + off;
313                                 if (pos >= dir->i_size) {
314                                         dir->i_size += BFS_DIRENT_SIZE;
315                                         dir->i_ctime = CURRENT_TIME_SEC;
316                                 }
317                                 dir->i_mtime = CURRENT_TIME_SEC;
318                                 mark_inode_dirty(dir);
319                                 de->ino = cpu_to_le16((u16)ino);
320                                 for (i = 0; i < BFS_NAMELEN; i++)
321                                         de->name[i] =
322                                                 (i < namelen) ? name[i] : 0;
323                                 mark_buffer_dirty(bh);
324                                 brelse(bh);
325                                 return 0;
326                         }
327                 }
328                 brelse(bh);
329         }
330         return -ENOSPC;
331 }
332
333 static inline int bfs_namecmp(int len, const unsigned char *name,
334                                                         const char *buffer)
335 {
336         if ((len < BFS_NAMELEN) && buffer[len])
337                 return 0;
338         return !memcmp(name, buffer, len);
339 }
340
341 static struct buffer_head *bfs_find_entry(struct inode *dir,
342                         const unsigned char *name, int namelen,
343                         struct bfs_dirent **res_dir)
344 {
345         unsigned long block = 0, offset = 0;
346         struct buffer_head *bh = NULL;
347         struct bfs_dirent *de;
348
349         *res_dir = NULL;
350         if (namelen > BFS_NAMELEN)
351                 return NULL;
352
353         while (block * BFS_BSIZE + offset < dir->i_size) {
354                 if (!bh) {
355                         bh = sb_bread(dir->i_sb, BFS_I(dir)->i_sblock + block);
356                         if (!bh) {
357                                 block++;
358                                 continue;
359                         }
360                 }
361                 de = (struct bfs_dirent *)(bh->b_data + offset);
362                 offset += BFS_DIRENT_SIZE;
363                 if (le16_to_cpu(de->ino) &&
364                                 bfs_namecmp(namelen, name, de->name)) {
365                         *res_dir = de;
366                         return bh;
367                 }
368                 if (offset < bh->b_size)
369                         continue;
370                 brelse(bh);
371                 bh = NULL;
372                 offset = 0;
373                 block++;
374         }
375         brelse(bh);
376         return NULL;
377 }