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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 unsigned int offset;
36 int block;
37
38 lock_kernel();
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 unlock_kernel();
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 unlock_kernel();
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 unlock_kernel();
75 return 0;
76}
77
78const struct file_operations bfs_dir_operations = {
79 .read = generic_read_dir,
80 .readdir = bfs_readdir,
81 .fsync = file_fsync,
82};
83
84extern void dump_imap(const char *, struct super_block *);
85
86static int bfs_create(struct inode *dir, struct dentry *dentry, int mode,
87 struct nameidata *nd)
88{
89 int err;
90 struct inode *inode;
91 struct super_block *s = dir->i_sb;
92 struct bfs_sb_info *info = BFS_SB(s);
93 unsigned long ino;
94
95 inode = new_inode(s);
96 if (!inode)
97 return -ENOSPC;
98 lock_kernel();
99 ino = find_first_zero_bit(info->si_imap, info->si_lasti);
100 if (ino > info->si_lasti) {
101 unlock_kernel();
102 iput(inode);
103 return -ENOSPC;
104 }
105 set_bit(ino, info->si_imap);
106 info->si_freei--;
107 inode->i_uid = current->fsuid;
108 inode->i_gid = (dir->i_mode & S_ISGID) ? dir->i_gid : current->fsgid;
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_mode = mode;
115 inode->i_ino = ino;
116 BFS_I(inode)->i_dsk_ino = ino;
117 BFS_I(inode)->i_sblock = 0;
118 BFS_I(inode)->i_eblock = 0;
119 insert_inode_hash(inode);
120 mark_inode_dirty(inode);
121 dump_imap("create", s);
122
123 err = bfs_add_entry(dir, dentry->d_name.name, dentry->d_name.len,
124 inode->i_ino);
125 if (err) {
126 inode_dec_link_count(inode);
127 iput(inode);
128 unlock_kernel();
129 return err;
130 }
131 unlock_kernel();
132 d_instantiate(dentry, inode);
133 return 0;
134}
135
136static struct dentry *bfs_lookup(struct inode *dir, struct dentry *dentry,
137 struct nameidata *nd)
138{
139 struct inode *inode = NULL;
140 struct buffer_head *bh;
141 struct bfs_dirent *de;
142
143 if (dentry->d_name.len > BFS_NAMELEN)
144 return ERR_PTR(-ENAMETOOLONG);
145
146 lock_kernel();
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 = iget(dir->i_sb, ino);
152 if (!inode) {
153 unlock_kernel();
154 return ERR_PTR(-EACCES);
155 }
156 }
157 unlock_kernel();
158 d_add(dentry, inode);
159 return NULL;
160}
161
162static int bfs_link(struct dentry *old, struct inode *dir,
163 struct dentry *new)
164{
165 struct inode *inode = old->d_inode;
166 int err;
167
168 lock_kernel();
169 err = bfs_add_entry(dir, new->d_name.name, new->d_name.len,
170 inode->i_ino);
171 if (err) {
172 unlock_kernel();
173 return err;
174 }
175 inc_nlink(inode);
176 inode->i_ctime = CURRENT_TIME_SEC;
177 mark_inode_dirty(inode);
178 atomic_inc(&inode->i_count);
179 d_instantiate(new, inode);
180 unlock_kernel();
181 return 0;
182}
183
184static int bfs_unlink(struct inode *dir, struct dentry *dentry)
185{
186 int error = -ENOENT;
187 struct inode *inode;
188 struct buffer_head *bh;
189 struct bfs_dirent *de;
190
191 inode = dentry->d_inode;
192 lock_kernel();
193 bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
194 if (!bh || (le16_to_cpu(de->ino) != inode->i_ino))
195 goto out_brelse;
196
197 if (!inode->i_nlink) {
198 printf("unlinking non-existent file %s:%lu (nlink=%d)\n",
199 inode->i_sb->s_id, inode->i_ino,
200 inode->i_nlink);
201 inode->i_nlink = 1;
202 }
203 de->ino = 0;
204 mark_buffer_dirty(bh);
205 dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
206 mark_inode_dirty(dir);
207 inode->i_ctime = dir->i_ctime;
208 inode_dec_link_count(inode);
209 error = 0;
210
211out_brelse:
212 brelse(bh);
213 unlock_kernel();
214 return error;
215}
216
217static int bfs_rename(struct inode *old_dir, struct dentry *old_dentry,
218 struct inode *new_dir, struct dentry *new_dentry)
219{
220 struct inode *old_inode, *new_inode;
221 struct buffer_head *old_bh, *new_bh;
222 struct bfs_dirent *old_de, *new_de;
223 int error = -ENOENT;
224
225 old_bh = new_bh = NULL;
226 old_inode = old_dentry->d_inode;
227 if (S_ISDIR(old_inode->i_mode))
228 return -EINVAL;
229
230 lock_kernel();
231 old_bh = bfs_find_entry(old_dir,
232 old_dentry->d_name.name,
233 old_dentry->d_name.len, &old_de);
234
235 if (!old_bh || (le16_to_cpu(old_de->ino) != old_inode->i_ino))
236 goto end_rename;
237
238 error = -EPERM;
239 new_inode = new_dentry->d_inode;
240 new_bh = bfs_find_entry(new_dir,
241 new_dentry->d_name.name,
242 new_dentry->d_name.len, &new_de);
243
244 if (new_bh && !new_inode) {
245 brelse(new_bh);
246 new_bh = NULL;
247 }
248 if (!new_bh) {
249 error = bfs_add_entry(new_dir,
250 new_dentry->d_name.name,
251 new_dentry->d_name.len,
252 old_inode->i_ino);
253 if (error)
254 goto end_rename;
255 }
256 old_de->ino = 0;
257 old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
258 mark_inode_dirty(old_dir);
259 if (new_inode) {
260 new_inode->i_ctime = CURRENT_TIME_SEC;
261 inode_dec_link_count(new_inode);
262 }
263 mark_buffer_dirty(old_bh);
264 error = 0;
265
266end_rename:
267 unlock_kernel();
268 brelse(old_bh);
269 brelse(new_bh);
270 return error;
271}
272
273const struct inode_operations bfs_dir_inops = {
274 .create = bfs_create,
275 .lookup = bfs_lookup,
276 .link = bfs_link,
277 .unlink = bfs_unlink,
278 .rename = bfs_rename,
279};
280
281static int bfs_add_entry(struct inode *dir, const unsigned char *name,
282 int namelen, int ino)
283{
284 struct buffer_head *bh;
285 struct bfs_dirent *de;
286 int block, sblock, eblock, off, pos;
287 int i;
288
289 dprintf("name=%s, namelen=%d\n", name, namelen);
290
291 if (!namelen)
292 return -ENOENT;
293 if (namelen > BFS_NAMELEN)
294 return -ENAMETOOLONG;
295
296 sblock = BFS_I(dir)->i_sblock;
297 eblock = BFS_I(dir)->i_eblock;
298 for (block = sblock; block <= eblock; block++) {
299 bh = sb_bread(dir->i_sb, block);
300 if (!bh)
301 return -ENOSPC;
302 for (off = 0; off < BFS_BSIZE; off += BFS_DIRENT_SIZE) {
303 de = (struct bfs_dirent *)(bh->b_data + off);
304 if (!de->ino) {
305 pos = (block - sblock) * BFS_BSIZE + off;
306 if (pos >= dir->i_size) {
307 dir->i_size += BFS_DIRENT_SIZE;
308 dir->i_ctime = CURRENT_TIME_SEC;
309 }
310 dir->i_mtime = CURRENT_TIME_SEC;
311 mark_inode_dirty(dir);
312 de->ino = cpu_to_le16((u16)ino);
313 for (i = 0; i < BFS_NAMELEN; i++)
314 de->name[i] =
315 (i < namelen) ? name[i] : 0;
316 mark_buffer_dirty(bh);
317 brelse(bh);
318 return 0;
319 }
320 }
321 brelse(bh);
322 }
323 return -ENOSPC;
324}
325
326static inline int bfs_namecmp(int len, const unsigned char *name,
327 const char *buffer)
328{
329 if ((len < BFS_NAMELEN) && buffer[len])
330 return 0;
331 return !memcmp(name, buffer, len);
332}
333
334static struct buffer_head *bfs_find_entry(struct inode *dir,
335 const unsigned char *name, int namelen,
336 struct bfs_dirent **res_dir)
337{
338 unsigned long block = 0, offset = 0;
339 struct buffer_head *bh = NULL;
340 struct bfs_dirent *de;
341
342 *res_dir = NULL;
343 if (namelen > BFS_NAMELEN)
344 return NULL;
345
346 while (block * BFS_BSIZE + offset < dir->i_size) {
347 if (!bh) {
348 bh = sb_bread(dir->i_sb, BFS_I(dir)->i_sblock + block);
349 if (!bh) {
350 block++;
351 continue;
352 }
353 }
354 de = (struct bfs_dirent *)(bh->b_data + offset);
355 offset += BFS_DIRENT_SIZE;
356 if (le16_to_cpu(de->ino) &&
357 bfs_namecmp(namelen, name, de->name)) {
358 *res_dir = de;
359 return bh;
360 }
361 if (offset < bh->b_size)
362 continue;
363 brelse(bh);
364 bh = NULL;
365 offset = 0;
366 block++;
367 }
368 brelse(bh);
369 return NULL;
370}
371
