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9#include <linux/time.h>
10#include <linux/string.h>
11#include <linux/fs.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, struct dir_context *ctx)
31{
32 struct inode *dir = file_inode(f);
33 struct buffer_head *bh;
34 struct bfs_dirent *de;
35 unsigned int offset;
36 int block;
37
38 if (ctx->pos & (BFS_DIRENT_SIZE - 1)) {
39 printf("Bad f_pos=%08lx for %s:%08lx\n",
40 (unsigned long)ctx->pos,
41 dir->i_sb->s_id, dir->i_ino);
42 return -EINVAL;
43 }
44
45 while (ctx->pos < dir->i_size) {
46 offset = ctx->pos & (BFS_BSIZE - 1);
47 block = BFS_I(dir)->i_sblock + (ctx->pos >> BFS_BSIZE_BITS);
48 bh = sb_bread(dir->i_sb, block);
49 if (!bh) {
50 ctx->pos += BFS_BSIZE - offset;
51 continue;
52 }
53 do {
54 de = (struct bfs_dirent *)(bh->b_data + offset);
55 if (de->ino) {
56 int size = strnlen(de->name, BFS_NAMELEN);
57 if (!dir_emit(ctx, de->name, size,
58 le16_to_cpu(de->ino),
59 DT_UNKNOWN)) {
60 brelse(bh);
61 return 0;
62 }
63 }
64 offset += BFS_DIRENT_SIZE;
65 ctx->pos += BFS_DIRENT_SIZE;
66 } while ((offset < BFS_BSIZE) && (ctx->pos < dir->i_size));
67 brelse(bh);
68 }
69 return 0;
70}
71
72const struct file_operations bfs_dir_operations = {
73 .read = generic_read_dir,
74 .iterate_shared = bfs_readdir,
75 .fsync = generic_file_fsync,
76 .llseek = generic_file_llseek,
77};
78
79static int bfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
80 bool excl)
81{
82 int err;
83 struct inode *inode;
84 struct super_block *s = dir->i_sb;
85 struct bfs_sb_info *info = BFS_SB(s);
86 unsigned long ino;
87
88 inode = new_inode(s);
89 if (!inode)
90 return -ENOMEM;
91 mutex_lock(&info->bfs_lock);
92 ino = find_first_zero_bit(info->si_imap, info->si_lasti + 1);
93 if (ino > info->si_lasti) {
94 mutex_unlock(&info->bfs_lock);
95 iput(inode);
96 return -ENOSPC;
97 }
98 set_bit(ino, info->si_imap);
99 info->si_freei--;
100 inode_init_owner(inode, dir, mode);
101 inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
102 inode->i_blocks = 0;
103 inode->i_op = &bfs_file_inops;
104 inode->i_fop = &bfs_file_operations;
105 inode->i_mapping->a_ops = &bfs_aops;
106 inode->i_ino = ino;
107 BFS_I(inode)->i_dsk_ino = ino;
108 BFS_I(inode)->i_sblock = 0;
109 BFS_I(inode)->i_eblock = 0;
110 insert_inode_hash(inode);
111 mark_inode_dirty(inode);
112 bfs_dump_imap("create", s);
113
114 err = bfs_add_entry(dir, dentry->d_name.name, dentry->d_name.len,
115 inode->i_ino);
116 if (err) {
117 inode_dec_link_count(inode);
118 mutex_unlock(&info->bfs_lock);
119 iput(inode);
120 return err;
121 }
122 mutex_unlock(&info->bfs_lock);
123 d_instantiate(dentry, inode);
124 return 0;
125}
126
127static struct dentry *bfs_lookup(struct inode *dir, struct dentry *dentry,
128 unsigned int flags)
129{
130 struct inode *inode = NULL;
131 struct buffer_head *bh;
132 struct bfs_dirent *de;
133 struct bfs_sb_info *info = BFS_SB(dir->i_sb);
134
135 if (dentry->d_name.len > BFS_NAMELEN)
136 return ERR_PTR(-ENAMETOOLONG);
137
138 mutex_lock(&info->bfs_lock);
139 bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
140 if (bh) {
141 unsigned long ino = (unsigned long)le16_to_cpu(de->ino);
142 brelse(bh);
143 inode = bfs_iget(dir->i_sb, ino);
144 if (IS_ERR(inode)) {
145 mutex_unlock(&info->bfs_lock);
146 return ERR_CAST(inode);
147 }
148 }
149 mutex_unlock(&info->bfs_lock);
150 d_add(dentry, inode);
151 return NULL;
152}
153
154static int bfs_link(struct dentry *old, struct inode *dir,
155 struct dentry *new)
156{
157 struct inode *inode = d_inode(old);
158 struct bfs_sb_info *info = BFS_SB(inode->i_sb);
159 int err;
160
161 mutex_lock(&info->bfs_lock);
162 err = bfs_add_entry(dir, new->d_name.name, new->d_name.len,
163 inode->i_ino);
164 if (err) {
165 mutex_unlock(&info->bfs_lock);
166 return err;
167 }
168 inc_nlink(inode);
169 inode->i_ctime = current_time(inode);
170 mark_inode_dirty(inode);
171 ihold(inode);
172 d_instantiate(new, inode);
173 mutex_unlock(&info->bfs_lock);
174 return 0;
175}
176
177static int bfs_unlink(struct inode *dir, struct dentry *dentry)
178{
179 int error = -ENOENT;
180 struct inode *inode = d_inode(dentry);
181 struct buffer_head *bh;
182 struct bfs_dirent *de;
183 struct bfs_sb_info *info = BFS_SB(inode->i_sb);
184
185 mutex_lock(&info->bfs_lock);
186 bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
187 if (!bh || (le16_to_cpu(de->ino) != inode->i_ino))
188 goto out_brelse;
189
190 if (!inode->i_nlink) {
191 printf("unlinking non-existent file %s:%lu (nlink=%d)\n",
192 inode->i_sb->s_id, inode->i_ino,
193 inode->i_nlink);
194 set_nlink(inode, 1);
195 }
196 de->ino = 0;
197 mark_buffer_dirty_inode(bh, dir);
198 dir->i_ctime = dir->i_mtime = current_time(dir);
199 mark_inode_dirty(dir);
200 inode->i_ctime = dir->i_ctime;
201 inode_dec_link_count(inode);
202 error = 0;
203
204out_brelse:
205 brelse(bh);
206 mutex_unlock(&info->bfs_lock);
207 return error;
208}
209
210static int bfs_rename(struct inode *old_dir, struct dentry *old_dentry,
211 struct inode *new_dir, struct dentry *new_dentry,
212 unsigned int flags)
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 if (flags & ~RENAME_NOREPLACE)
221 return -EINVAL;
222
223 old_bh = new_bh = NULL;
224 old_inode = d_inode(old_dentry);
225 if (S_ISDIR(old_inode->i_mode))
226 return -EINVAL;
227
228 info = BFS_SB(old_inode->i_sb);
229
230 mutex_lock(&info->bfs_lock);
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 = d_inode(new_dentry);
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(old_dir);
258 mark_inode_dirty(old_dir);
259 if (new_inode) {
260 new_inode->i_ctime = current_time(new_inode);
261 inode_dec_link_count(new_inode);
262 }
263 mark_buffer_dirty_inode(old_bh, old_dir);
264 error = 0;
265
266end_rename:
267 mutex_unlock(&info->bfs_lock);
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 -EIO;
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(dir);
309 }
310 dir->i_mtime = current_time(dir);
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_inode(bh, dir);
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
