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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_shared = bfs_readdir,
74 .fsync = generic_file_fsync,
75 .llseek = generic_file_llseek,
76};
77
78static int bfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
79 bool excl)
80{
81 int err;
82 struct inode *inode;
83 struct super_block *s = dir->i_sb;
84 struct bfs_sb_info *info = BFS_SB(s);
85 unsigned long ino;
86
87 inode = new_inode(s);
88 if (!inode)
89 return -ENOMEM;
90 mutex_lock(&info->bfs_lock);
91 ino = find_first_zero_bit(info->si_imap, info->si_lasti + 1);
92 if (ino > info->si_lasti) {
93 mutex_unlock(&info->bfs_lock);
94 iput(inode);
95 return -ENOSPC;
96 }
97 set_bit(ino, info->si_imap);
98 info->si_freei--;
99 inode_init_owner(inode, dir, mode);
100 inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
101 inode->i_blocks = 0;
102 inode->i_op = &bfs_file_inops;
103 inode->i_fop = &bfs_file_operations;
104 inode->i_mapping->a_ops = &bfs_aops;
105 inode->i_ino = ino;
106 BFS_I(inode)->i_dsk_ino = ino;
107 BFS_I(inode)->i_sblock = 0;
108 BFS_I(inode)->i_eblock = 0;
109 insert_inode_hash(inode);
110 mark_inode_dirty(inode);
111 bfs_dump_imap("create", s);
112
113 err = bfs_add_entry(dir, dentry->d_name.name, dentry->d_name.len,
114 inode->i_ino);
115 if (err) {
116 inode_dec_link_count(inode);
117 mutex_unlock(&info->bfs_lock);
118 iput(inode);
119 return err;
120 }
121 mutex_unlock(&info->bfs_lock);
122 d_instantiate(dentry, inode);
123 return 0;
124}
125
126static struct dentry *bfs_lookup(struct inode *dir, struct dentry *dentry,
127 unsigned int flags)
128{
129 struct inode *inode = NULL;
130 struct buffer_head *bh;
131 struct bfs_dirent *de;
132 struct bfs_sb_info *info = BFS_SB(dir->i_sb);
133
134 if (dentry->d_name.len > BFS_NAMELEN)
135 return ERR_PTR(-ENAMETOOLONG);
136
137 mutex_lock(&info->bfs_lock);
138 bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
139 if (bh) {
140 unsigned long ino = (unsigned long)le16_to_cpu(de->ino);
141 brelse(bh);
142 inode = bfs_iget(dir->i_sb, ino);
143 if (IS_ERR(inode)) {
144 mutex_unlock(&info->bfs_lock);
145 return ERR_CAST(inode);
146 }
147 }
148 mutex_unlock(&info->bfs_lock);
149 d_add(dentry, inode);
150 return NULL;
151}
152
153static int bfs_link(struct dentry *old, struct inode *dir,
154 struct dentry *new)
155{
156 struct inode *inode = d_inode(old);
157 struct bfs_sb_info *info = BFS_SB(inode->i_sb);
158 int err;
159
160 mutex_lock(&info->bfs_lock);
161 err = bfs_add_entry(dir, new->d_name.name, new->d_name.len,
162 inode->i_ino);
163 if (err) {
164 mutex_unlock(&info->bfs_lock);
165 return err;
166 }
167 inc_nlink(inode);
168 inode->i_ctime = current_time(inode);
169 mark_inode_dirty(inode);
170 ihold(inode);
171 d_instantiate(new, inode);
172 mutex_unlock(&info->bfs_lock);
173 return 0;
174}
175
176static int bfs_unlink(struct inode *dir, struct dentry *dentry)
177{
178 int error = -ENOENT;
179 struct inode *inode = d_inode(dentry);
180 struct buffer_head *bh;
181 struct bfs_dirent *de;
182 struct bfs_sb_info *info = BFS_SB(inode->i_sb);
183
184 mutex_lock(&info->bfs_lock);
185 bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
186 if (!bh || (le16_to_cpu(de->ino) != inode->i_ino))
187 goto out_brelse;
188
189 if (!inode->i_nlink) {
190 printf("unlinking non-existent file %s:%lu (nlink=%d)\n",
191 inode->i_sb->s_id, inode->i_ino,
192 inode->i_nlink);
193 set_nlink(inode, 1);
194 }
195 de->ino = 0;
196 mark_buffer_dirty_inode(bh, dir);
197 dir->i_ctime = dir->i_mtime = current_time(dir);
198 mark_inode_dirty(dir);
199 inode->i_ctime = dir->i_ctime;
200 inode_dec_link_count(inode);
201 error = 0;
202
203out_brelse:
204 brelse(bh);
205 mutex_unlock(&info->bfs_lock);
206 return error;
207}
208
209static int bfs_rename(struct inode *old_dir, struct dentry *old_dentry,
210 struct inode *new_dir, struct dentry *new_dentry,
211 unsigned int flags)
212{
213 struct inode *old_inode, *new_inode;
214 struct buffer_head *old_bh, *new_bh;
215 struct bfs_dirent *old_de, *new_de;
216 struct bfs_sb_info *info;
217 int error = -ENOENT;
218
219 if (flags & ~RENAME_NOREPLACE)
220 return -EINVAL;
221
222 old_bh = new_bh = NULL;
223 old_inode = d_inode(old_dentry);
224 if (S_ISDIR(old_inode->i_mode))
225 return -EINVAL;
226
227 info = BFS_SB(old_inode->i_sb);
228
229 mutex_lock(&info->bfs_lock);
230 old_bh = bfs_find_entry(old_dir,
231 old_dentry->d_name.name,
232 old_dentry->d_name.len, &old_de);
233
234 if (!old_bh || (le16_to_cpu(old_de->ino) != old_inode->i_ino))
235 goto end_rename;
236
237 error = -EPERM;
238 new_inode = d_inode(new_dentry);
239 new_bh = bfs_find_entry(new_dir,
240 new_dentry->d_name.name,
241 new_dentry->d_name.len, &new_de);
242
243 if (new_bh && !new_inode) {
244 brelse(new_bh);
245 new_bh = NULL;
246 }
247 if (!new_bh) {
248 error = bfs_add_entry(new_dir,
249 new_dentry->d_name.name,
250 new_dentry->d_name.len,
251 old_inode->i_ino);
252 if (error)
253 goto end_rename;
254 }
255 old_de->ino = 0;
256 old_dir->i_ctime = old_dir->i_mtime = current_time(old_dir);
257 mark_inode_dirty(old_dir);
258 if (new_inode) {
259 new_inode->i_ctime = current_time(new_inode);
260 inode_dec_link_count(new_inode);
261 }
262 mark_buffer_dirty_inode(old_bh, old_dir);
263 error = 0;
264
265end_rename:
266 mutex_unlock(&info->bfs_lock);
267 brelse(old_bh);
268 brelse(new_bh);
269 return error;
270}
271
272const struct inode_operations bfs_dir_inops = {
273 .create = bfs_create,
274 .lookup = bfs_lookup,
275 .link = bfs_link,
276 .unlink = bfs_unlink,
277 .rename = bfs_rename,
278};
279
280static int bfs_add_entry(struct inode *dir, const unsigned char *name,
281 int namelen, int ino)
282{
283 struct buffer_head *bh;
284 struct bfs_dirent *de;
285 int block, sblock, eblock, off, pos;
286 int i;
287
288 dprintf("name=%s, namelen=%d\n", name, namelen);
289
290 if (!namelen)
291 return -ENOENT;
292 if (namelen > BFS_NAMELEN)
293 return -ENAMETOOLONG;
294
295 sblock = BFS_I(dir)->i_sblock;
296 eblock = BFS_I(dir)->i_eblock;
297 for (block = sblock; block <= eblock; block++) {
298 bh = sb_bread(dir->i_sb, block);
299 if (!bh)
300 return -EIO;
301 for (off = 0; off < BFS_BSIZE; off += BFS_DIRENT_SIZE) {
302 de = (struct bfs_dirent *)(bh->b_data + off);
303 if (!de->ino) {
304 pos = (block - sblock) * BFS_BSIZE + off;
305 if (pos >= dir->i_size) {
306 dir->i_size += BFS_DIRENT_SIZE;
307 dir->i_ctime = current_time(dir);
308 }
309 dir->i_mtime = current_time(dir);
310 mark_inode_dirty(dir);
311 de->ino = cpu_to_le16((u16)ino);
312 for (i = 0; i < BFS_NAMELEN; i++)
313 de->name[i] =
314 (i < namelen) ? name[i] : 0;
315 mark_buffer_dirty_inode(bh, dir);
316 brelse(bh);
317 return 0;
318 }
319 }
320 brelse(bh);
321 }
322 return -ENOSPC;
323}
324
325static inline int bfs_namecmp(int len, const unsigned char *name,
326 const char *buffer)
327{
328 if ((len < BFS_NAMELEN) && buffer[len])
329 return 0;
330 return !memcmp(name, buffer, len);
331}
332
333static struct buffer_head *bfs_find_entry(struct inode *dir,
334 const unsigned char *name, int namelen,
335 struct bfs_dirent **res_dir)
336{
337 unsigned long block = 0, offset = 0;
338 struct buffer_head *bh = NULL;
339 struct bfs_dirent *de;
340
341 *res_dir = NULL;
342 if (namelen > BFS_NAMELEN)
343 return NULL;
344
345 while (block * BFS_BSIZE + offset < dir->i_size) {
346 if (!bh) {
347 bh = sb_bread(dir->i_sb, BFS_I(dir)->i_sblock + block);
348 if (!bh) {
349 block++;
350 continue;
351 }
352 }
353 de = (struct bfs_dirent *)(bh->b_data + offset);
354 offset += BFS_DIRENT_SIZE;
355 if (le16_to_cpu(de->ino) &&
356 bfs_namecmp(namelen, name, de->name)) {
357 *res_dir = de;
358 return bh;
359 }
360 if (offset < bh->b_size)
361 continue;
362 brelse(bh);
363 bh = NULL;
364 offset = 0;
365 block++;
366 }
367 brelse(bh);
368 return NULL;
369}
370
