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