headers: smp_lock.h redux
[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          = simple_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->i_uid = current_fsuid();
109         inode->i_gid = (dir->i_mode & S_ISGID) ? dir->i_gid : current_fsgid();
110         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
111         inode->i_blocks = 0;
112         inode->i_op = &bfs_file_inops;
113         inode->i_fop = &bfs_file_operations;
114         inode->i_mapping->a_ops = &bfs_aops;
115         inode->i_mode = mode;
116         inode->i_ino = ino;
117         BFS_I(inode)->i_dsk_ino = ino;
118         BFS_I(inode)->i_sblock = 0;
119         BFS_I(inode)->i_eblock = 0;
120         insert_inode_hash(inode);
121         mark_inode_dirty(inode);
122         dump_imap("create", s);
123
124         err = bfs_add_entry(dir, dentry->d_name.name, dentry->d_name.len,
125                                                         inode->i_ino);
126         if (err) {
127                 inode_dec_link_count(inode);
128                 mutex_unlock(&info->bfs_lock);
129                 iput(inode);
130                 return err;
131         }
132         mutex_unlock(&info->bfs_lock);
133         d_instantiate(dentry, inode);
134         return 0;
135 }
136
137 static struct dentry *bfs_lookup(struct inode *dir, struct dentry *dentry,
138                                                 struct nameidata *nd)
139 {
140         struct inode *inode = NULL;
141         struct buffer_head *bh;
142         struct bfs_dirent *de;
143         struct bfs_sb_info *info = BFS_SB(dir->i_sb);
144
145         if (dentry->d_name.len > BFS_NAMELEN)
146                 return ERR_PTR(-ENAMETOOLONG);
147
148         mutex_lock(&info->bfs_lock);
149         bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
150         if (bh) {
151                 unsigned long ino = (unsigned long)le16_to_cpu(de->ino);
152                 brelse(bh);
153                 inode = bfs_iget(dir->i_sb, ino);
154                 if (IS_ERR(inode)) {
155                         mutex_unlock(&info->bfs_lock);
156                         return ERR_CAST(inode);
157                 }
158         }
159         mutex_unlock(&info->bfs_lock);
160         d_add(dentry, inode);
161         return NULL;
162 }
163
164 static int bfs_link(struct dentry *old, struct inode *dir,
165                                                 struct dentry *new)
166 {
167         struct inode *inode = old->d_inode;
168         struct bfs_sb_info *info = BFS_SB(inode->i_sb);
169         int err;
170
171         mutex_lock(&info->bfs_lock);
172         err = bfs_add_entry(dir, new->d_name.name, new->d_name.len,
173                                                         inode->i_ino);
174         if (err) {
175                 mutex_unlock(&info->bfs_lock);
176                 return err;
177         }
178         inc_nlink(inode);
179         inode->i_ctime = CURRENT_TIME_SEC;
180         mark_inode_dirty(inode);
181         atomic_inc(&inode->i_count);
182         d_instantiate(new, inode);
183         mutex_unlock(&info->bfs_lock);
184         return 0;
185 }
186
187 static int bfs_unlink(struct inode *dir, struct dentry *dentry)
188 {
189         int error = -ENOENT;
190         struct inode *inode = dentry->d_inode;
191         struct buffer_head *bh;
192         struct bfs_dirent *de;
193         struct bfs_sb_info *info = BFS_SB(inode->i_sb);
194
195         mutex_lock(&info->bfs_lock);
196         bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
197         if (!bh || (le16_to_cpu(de->ino) != inode->i_ino))
198                 goto out_brelse;
199
200         if (!inode->i_nlink) {
201                 printf("unlinking non-existent file %s:%lu (nlink=%d)\n",
202                                         inode->i_sb->s_id, inode->i_ino,
203                                         inode->i_nlink);
204                 inode->i_nlink = 1;
205         }
206         de->ino = 0;
207         mark_buffer_dirty_inode(bh, dir);
208         dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
209         mark_inode_dirty(dir);
210         inode->i_ctime = dir->i_ctime;
211         inode_dec_link_count(inode);
212         error = 0;
213
214 out_brelse:
215         brelse(bh);
216         mutex_unlock(&info->bfs_lock);
217         return error;
218 }
219
220 static int bfs_rename(struct inode *old_dir, struct dentry *old_dentry,
221                         struct inode *new_dir, struct dentry *new_dentry)
222 {
223         struct inode *old_inode, *new_inode;
224         struct buffer_head *old_bh, *new_bh;
225         struct bfs_dirent *old_de, *new_de;
226         struct bfs_sb_info *info;
227         int error = -ENOENT;
228
229         old_bh = new_bh = NULL;
230         old_inode = old_dentry->d_inode;
231         if (S_ISDIR(old_inode->i_mode))
232                 return -EINVAL;
233
234         info = BFS_SB(old_inode->i_sb);
235
236         mutex_lock(&info->bfs_lock);
237         old_bh = bfs_find_entry(old_dir, 
238                                 old_dentry->d_name.name, 
239                                 old_dentry->d_name.len, &old_de);
240
241         if (!old_bh || (le16_to_cpu(old_de->ino) != old_inode->i_ino))
242                 goto end_rename;
243
244         error = -EPERM;
245         new_inode = new_dentry->d_inode;
246         new_bh = bfs_find_entry(new_dir, 
247                                 new_dentry->d_name.name, 
248                                 new_dentry->d_name.len, &new_de);
249
250         if (new_bh && !new_inode) {
251                 brelse(new_bh);
252                 new_bh = NULL;
253         }
254         if (!new_bh) {
255                 error = bfs_add_entry(new_dir, 
256                                         new_dentry->d_name.name,
257                                         new_dentry->d_name.len,
258                                         old_inode->i_ino);
259                 if (error)
260                         goto end_rename;
261         }
262         old_de->ino = 0;
263         old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
264         mark_inode_dirty(old_dir);
265         if (new_inode) {
266                 new_inode->i_ctime = CURRENT_TIME_SEC;
267                 inode_dec_link_count(new_inode);
268         }
269         mark_buffer_dirty_inode(old_bh, old_dir);
270         error = 0;
271
272 end_rename:
273         mutex_unlock(&info->bfs_lock);
274         brelse(old_bh);
275         brelse(new_bh);
276         return error;
277 }
278
279 const struct inode_operations bfs_dir_inops = {
280         .create                 = bfs_create,
281         .lookup                 = bfs_lookup,
282         .link                   = bfs_link,
283         .unlink                 = bfs_unlink,
284         .rename                 = bfs_rename,
285 };
286
287 static int bfs_add_entry(struct inode *dir, const unsigned char *name,
288                                                         int namelen, int ino)
289 {
290         struct buffer_head *bh;
291         struct bfs_dirent *de;
292         int block, sblock, eblock, off, pos;
293         int i;
294
295         dprintf("name=%s, namelen=%d\n", name, namelen);
296
297         if (!namelen)
298                 return -ENOENT;
299         if (namelen > BFS_NAMELEN)
300                 return -ENAMETOOLONG;
301
302         sblock = BFS_I(dir)->i_sblock;
303         eblock = BFS_I(dir)->i_eblock;
304         for (block = sblock; block <= eblock; block++) {
305                 bh = sb_bread(dir->i_sb, block);
306                 if (!bh)
307                         return -ENOSPC;
308                 for (off = 0; off < BFS_BSIZE; off += BFS_DIRENT_SIZE) {
309                         de = (struct bfs_dirent *)(bh->b_data + off);
310                         if (!de->ino) {
311                                 pos = (block - sblock) * BFS_BSIZE + off;
312                                 if (pos >= dir->i_size) {
313                                         dir->i_size += BFS_DIRENT_SIZE;
314                                         dir->i_ctime = CURRENT_TIME_SEC;
315                                 }
316                                 dir->i_mtime = CURRENT_TIME_SEC;
317                                 mark_inode_dirty(dir);
318                                 de->ino = cpu_to_le16((u16)ino);
319                                 for (i = 0; i < BFS_NAMELEN; i++)
320                                         de->name[i] =
321                                                 (i < namelen) ? name[i] : 0;
322                                 mark_buffer_dirty_inode(bh, dir);
323                                 brelse(bh);
324                                 return 0;
325                         }
326                 }
327                 brelse(bh);
328         }
329         return -ENOSPC;
330 }
331
332 static inline int bfs_namecmp(int len, const unsigned char *name,
333                                                         const char *buffer)
334 {
335         if ((len < BFS_NAMELEN) && buffer[len])
336                 return 0;
337         return !memcmp(name, buffer, len);
338 }
339
340 static struct buffer_head *bfs_find_entry(struct inode *dir,
341                         const unsigned char *name, int namelen,
342                         struct bfs_dirent **res_dir)
343 {
344         unsigned long block = 0, offset = 0;
345         struct buffer_head *bh = NULL;
346         struct bfs_dirent *de;
347
348         *res_dir = NULL;
349         if (namelen > BFS_NAMELEN)
350                 return NULL;
351
352         while (block * BFS_BSIZE + offset < dir->i_size) {
353                 if (!bh) {
354                         bh = sb_bread(dir->i_sb, BFS_I(dir)->i_sblock + block);
355                         if (!bh) {
356                                 block++;
357                                 continue;
358                         }
359                 }
360                 de = (struct bfs_dirent *)(bh->b_data + offset);
361                 offset += BFS_DIRENT_SIZE;
362                 if (le16_to_cpu(de->ino) &&
363                                 bfs_namecmp(namelen, name, de->name)) {
364                         *res_dir = de;
365                         return bh;
366                 }
367                 if (offset < bh->b_size)
368                         continue;
369                 brelse(bh);
370                 bh = NULL;
371                 offset = 0;
372                 block++;
373         }
374         brelse(bh);
375         return NULL;
376 }