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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
24static int bfs_add_entry(struct inode *dir, const unsigned char *name,
25 int namelen, int ino);
26static struct buffer_head *bfs_find_entry(struct inode *dir,
27 const unsigned char *name, int namelen,
28 struct bfs_dirent **res_dir);
29
30static 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
79const 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
86extern void dump_imap(const char *, struct super_block *);
87
88static 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
138static 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
165static 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
188static 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
215out_brelse:
216 brelse(bh);
217 mutex_unlock(&info->bfs_lock);
218 return error;
219}
220
221static 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
273end_rename:
274 mutex_unlock(&info->bfs_lock);
275 brelse(old_bh);
276 brelse(new_bh);
277 return error;
278}
279
280const 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
288static 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
333static 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
341static 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}
378
