685ecff3ab31728d2362a9be39f98dfbc76947c4
[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/buffer_head.h>
12 #include <linux/sched.h>
13 #include "bfs.h"
14
15 #undef DEBUG
16
17 #ifdef DEBUG
18 #define dprintf(x...)   printf(x)
19 #else
20 #define dprintf(x...)
21 #endif
22
23 static int bfs_add_entry(struct inode *dir, const unsigned char *name,
24                                                 int namelen, int ino);
25 static struct buffer_head *bfs_find_entry(struct inode *dir,
26                                 const unsigned char *name, int namelen,
27                                 struct bfs_dirent **res_dir);
28
29 static int bfs_readdir(struct file *f, void *dirent, filldir_t filldir)
30 {
31         struct inode *dir = f->f_path.dentry->d_inode;
32         struct buffer_head *bh;
33         struct bfs_dirent *de;
34         struct bfs_sb_info *info = BFS_SB(dir->i_sb);
35         unsigned int offset;
36         int block;
37
38         mutex_lock(&info->bfs_lock);
39
40         if (f->f_pos & (BFS_DIRENT_SIZE - 1)) {
41                 printf("Bad f_pos=%08lx for %s:%08lx\n",
42                                         (unsigned long)f->f_pos,
43                                         dir->i_sb->s_id, dir->i_ino);
44                 mutex_unlock(&info->bfs_lock);
45                 return -EBADF;
46         }
47
48         while (f->f_pos < dir->i_size) {
49                 offset = f->f_pos & (BFS_BSIZE - 1);
50                 block = BFS_I(dir)->i_sblock + (f->f_pos >> BFS_BSIZE_BITS);
51                 bh = sb_bread(dir->i_sb, block);
52                 if (!bh) {
53                         f->f_pos += BFS_BSIZE - offset;
54                         continue;
55                 }
56                 do {
57                         de = (struct bfs_dirent *)(bh->b_data + offset);
58                         if (de->ino) {
59                                 int size = strnlen(de->name, BFS_NAMELEN);
60                                 if (filldir(dirent, de->name, size, f->f_pos,
61                                                 le16_to_cpu(de->ino),
62                                                 DT_UNKNOWN) < 0) {
63                                         brelse(bh);
64                                         mutex_unlock(&info->bfs_lock);
65                                         return 0;
66                                 }
67                         }
68                         offset += BFS_DIRENT_SIZE;
69                         f->f_pos += BFS_DIRENT_SIZE;
70                 } while ((offset < BFS_BSIZE) && (f->f_pos < dir->i_size));
71                 brelse(bh);
72         }
73
74         mutex_unlock(&info->bfs_lock);
75         return 0;       
76 }
77
78 const struct file_operations bfs_dir_operations = {
79         .read           = generic_read_dir,
80         .readdir        = bfs_readdir,
81         .fsync          = generic_file_fsync,
82         .llseek         = generic_file_llseek,
83 };
84
85 extern void dump_imap(const char *, struct super_block *);
86
87 static int bfs_create(struct inode *dir, struct dentry *dentry, int mode,
88                                                 struct nameidata *nd)
89 {
90         int err;
91         struct inode *inode;
92         struct super_block *s = dir->i_sb;
93         struct bfs_sb_info *info = BFS_SB(s);
94         unsigned long ino;
95
96         inode = new_inode(s);
97         if (!inode)
98                 return -ENOSPC;
99         mutex_lock(&info->bfs_lock);
100         ino = find_first_zero_bit(info->si_imap, info->si_lasti);
101         if (ino > info->si_lasti) {
102                 mutex_unlock(&info->bfs_lock);
103                 iput(inode);
104                 return -ENOSPC;
105         }
106         set_bit(ino, info->si_imap);
107         info->si_freei--;
108         inode_init_owner(inode, dir, mode);
109         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
110         inode->i_blocks = 0;
111         inode->i_op = &bfs_file_inops;
112         inode->i_fop = &bfs_file_operations;
113         inode->i_mapping->a_ops = &bfs_aops;
114         inode->i_ino = ino;
115         BFS_I(inode)->i_dsk_ino = ino;
116         BFS_I(inode)->i_sblock = 0;
117         BFS_I(inode)->i_eblock = 0;
118         insert_inode_hash(inode);
119         mark_inode_dirty(inode);
120         dump_imap("create", s);
121
122         err = bfs_add_entry(dir, dentry->d_name.name, dentry->d_name.len,
123                                                         inode->i_ino);
124         if (err) {
125                 inode_dec_link_count(inode);
126                 mutex_unlock(&info->bfs_lock);
127                 iput(inode);
128                 return err;
129         }
130         mutex_unlock(&info->bfs_lock);
131         d_instantiate(dentry, inode);
132         return 0;
133 }
134
135 static struct dentry *bfs_lookup(struct inode *dir, struct dentry *dentry,
136                                                 struct nameidata *nd)
137 {
138         struct inode *inode = NULL;
139         struct buffer_head *bh;
140         struct bfs_dirent *de;
141         struct bfs_sb_info *info = BFS_SB(dir->i_sb);
142
143         if (dentry->d_name.len > BFS_NAMELEN)
144                 return ERR_PTR(-ENAMETOOLONG);
145
146         mutex_lock(&info->bfs_lock);
147         bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
148         if (bh) {
149                 unsigned long ino = (unsigned long)le16_to_cpu(de->ino);
150                 brelse(bh);
151                 inode = bfs_iget(dir->i_sb, ino);
152                 if (IS_ERR(inode)) {
153                         mutex_unlock(&info->bfs_lock);
154                         return ERR_CAST(inode);
155                 }
156         }
157         mutex_unlock(&info->bfs_lock);
158         d_add(dentry, inode);
159         return NULL;
160 }
161
162 static int bfs_link(struct dentry *old, struct inode *dir,
163                                                 struct dentry *new)
164 {
165         struct inode *inode = old->d_inode;
166         struct bfs_sb_info *info = BFS_SB(inode->i_sb);
167         int err;
168
169         mutex_lock(&info->bfs_lock);
170         err = bfs_add_entry(dir, new->d_name.name, new->d_name.len,
171                                                         inode->i_ino);
172         if (err) {
173                 mutex_unlock(&info->bfs_lock);
174                 return err;
175         }
176         inc_nlink(inode);
177         inode->i_ctime = CURRENT_TIME_SEC;
178         mark_inode_dirty(inode);
179         ihold(inode);
180         d_instantiate(new, inode);
181         mutex_unlock(&info->bfs_lock);
182         return 0;
183 }
184
185 static int bfs_unlink(struct inode *dir, struct dentry *dentry)
186 {
187         int error = -ENOENT;
188         struct inode *inode = dentry->d_inode;
189         struct buffer_head *bh;
190         struct bfs_dirent *de;
191         struct bfs_sb_info *info = BFS_SB(inode->i_sb);
192
193         mutex_lock(&info->bfs_lock);
194         bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
195         if (!bh || (le16_to_cpu(de->ino) != inode->i_ino))
196                 goto out_brelse;
197
198         if (!inode->i_nlink) {
199                 printf("unlinking non-existent file %s:%lu (nlink=%d)\n",
200                                         inode->i_sb->s_id, inode->i_ino,
201                                         inode->i_nlink);
202                 inode->i_nlink = 1;
203         }
204         de->ino = 0;
205         mark_buffer_dirty_inode(bh, dir);
206         dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
207         mark_inode_dirty(dir);
208         inode->i_ctime = dir->i_ctime;
209         inode_dec_link_count(inode);
210         error = 0;
211
212 out_brelse:
213         brelse(bh);
214         mutex_unlock(&info->bfs_lock);
215         return error;
216 }
217
218 static int bfs_rename(struct inode *old_dir, struct dentry *old_dentry,
219                         struct inode *new_dir, struct dentry *new_dentry)
220 {
221         struct inode *old_inode, *new_inode;
222         struct buffer_head *old_bh, *new_bh;
223         struct bfs_dirent *old_de, *new_de;
224         struct bfs_sb_info *info;
225         int error = -ENOENT;
226
227         old_bh = new_bh = NULL;
228         old_inode = old_dentry->d_inode;
229         if (S_ISDIR(old_inode->i_mode))
230                 return -EINVAL;
231
232         info = BFS_SB(old_inode->i_sb);
233
234         mutex_lock(&info->bfs_lock);
235         old_bh = bfs_find_entry(old_dir, 
236                                 old_dentry->d_name.name, 
237                                 old_dentry->d_name.len, &old_de);
238
239         if (!old_bh || (le16_to_cpu(old_de->ino) != old_inode->i_ino))
240                 goto end_rename;
241
242         error = -EPERM;
243         new_inode = new_dentry->d_inode;
244         new_bh = bfs_find_entry(new_dir, 
245                                 new_dentry->d_name.name, 
246                                 new_dentry->d_name.len, &new_de);
247
248         if (new_bh && !new_inode) {
249                 brelse(new_bh);
250                 new_bh = NULL;
251         }
252         if (!new_bh) {
253                 error = bfs_add_entry(new_dir, 
254                                         new_dentry->d_name.name,
255                                         new_dentry->d_name.len,
256                                         old_inode->i_ino);
257                 if (error)
258                         goto end_rename;
259         }
260         old_de->ino = 0;
261         old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
262         mark_inode_dirty(old_dir);
263         if (new_inode) {
264                 new_inode->i_ctime = CURRENT_TIME_SEC;
265                 inode_dec_link_count(new_inode);
266         }
267         mark_buffer_dirty_inode(old_bh, old_dir);
268         error = 0;
269
270 end_rename:
271         mutex_unlock(&info->bfs_lock);
272         brelse(old_bh);
273         brelse(new_bh);
274         return error;
275 }
276
277 const struct inode_operations bfs_dir_inops = {
278         .create                 = bfs_create,
279         .lookup                 = bfs_lookup,
280         .link                   = bfs_link,
281         .unlink                 = bfs_unlink,
282         .rename                 = bfs_rename,
283 };
284
285 static int bfs_add_entry(struct inode *dir, const unsigned char *name,
286                                                         int namelen, int ino)
287 {
288         struct buffer_head *bh;
289         struct bfs_dirent *de;
290         int block, sblock, eblock, off, pos;
291         int i;
292
293         dprintf("name=%s, namelen=%d\n", name, namelen);
294
295         if (!namelen)
296                 return -ENOENT;
297         if (namelen > BFS_NAMELEN)
298                 return -ENAMETOOLONG;
299
300         sblock = BFS_I(dir)->i_sblock;
301         eblock = BFS_I(dir)->i_eblock;
302         for (block = sblock; block <= eblock; block++) {
303                 bh = sb_bread(dir->i_sb, block);
304                 if (!bh)
305                         return -ENOSPC;
306                 for (off = 0; off < BFS_BSIZE; off += BFS_DIRENT_SIZE) {
307                         de = (struct bfs_dirent *)(bh->b_data + off);
308                         if (!de->ino) {
309                                 pos = (block - sblock) * BFS_BSIZE + off;
310                                 if (pos >= dir->i_size) {
311                                         dir->i_size += BFS_DIRENT_SIZE;
312                                         dir->i_ctime = CURRENT_TIME_SEC;
313                                 }
314                                 dir->i_mtime = CURRENT_TIME_SEC;
315                                 mark_inode_dirty(dir);
316                                 de->ino = cpu_to_le16((u16)ino);
317                                 for (i = 0; i < BFS_NAMELEN; i++)
318                                         de->name[i] =
319                                                 (i < namelen) ? name[i] : 0;
320                                 mark_buffer_dirty_inode(bh, dir);
321                                 brelse(bh);
322                                 return 0;
323                         }
324                 }
325                 brelse(bh);
326         }
327         return -ENOSPC;
328 }
329
330 static inline int bfs_namecmp(int len, const unsigned char *name,
331                                                         const char *buffer)
332 {
333         if ((len < BFS_NAMELEN) && buffer[len])
334                 return 0;
335         return !memcmp(name, buffer, len);
336 }
337
338 static struct buffer_head *bfs_find_entry(struct inode *dir,
339                         const unsigned char *name, int namelen,
340                         struct bfs_dirent **res_dir)
341 {
342         unsigned long block = 0, offset = 0;
343         struct buffer_head *bh = NULL;
344         struct bfs_dirent *de;
345
346         *res_dir = NULL;
347         if (namelen > BFS_NAMELEN)
348                 return NULL;
349
350         while (block * BFS_BSIZE + offset < dir->i_size) {
351                 if (!bh) {
352                         bh = sb_bread(dir->i_sb, BFS_I(dir)->i_sblock + block);
353                         if (!bh) {
354                                 block++;
355                                 continue;
356                         }
357                 }
358                 de = (struct bfs_dirent *)(bh->b_data + offset);
359                 offset += BFS_DIRENT_SIZE;
360                 if (le16_to_cpu(de->ino) &&
361                                 bfs_namecmp(namelen, name, de->name)) {
362                         *res_dir = de;
363                         return bh;
364                 }
365                 if (offset < bh->b_size)
366                         continue;
367                 brelse(bh);
368                 bh = NULL;
369                 offset = 0;
370                 block++;
371         }
372         brelse(bh);
373         return NULL;
374 }