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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
23static int bfs_add_entry(struct inode *dir, const unsigned char *name,
24 int namelen, int ino);
25static struct buffer_head *bfs_find_entry(struct inode *dir,
26 const unsigned char *name, int namelen,
27 struct bfs_dirent **res_dir);
28
29static 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
78const 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
85extern void dump_imap(const char *, struct super_block *);
86
87static 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
137static 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
164static 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
187static 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
214out_brelse:
215 brelse(bh);
216 mutex_unlock(&info->bfs_lock);
217 return error;
218}
219
220static 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
272end_rename:
273 mutex_unlock(&info->bfs_lock);
274 brelse(old_bh);
275 brelse(new_bh);
276 return error;
277}
278
279const 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
287static 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
332static 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
340static 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}
377
