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7#include <linux/sched.h>
8#include <linux/string.h>
9#include <linux/bfs_fs.h>
10#include <linux/locks.h>
11
12#include "bfs_defs.h"
13
14#undef DEBUG
15
16#ifdef DEBUG
17#define dprintf(x...) printf(x)
18#else
19#define dprintf(x...)
20#endif
21
22static int bfs_add_entry(struct inode * dir, const char * name, int namelen, int ino);
23static struct buffer_head * bfs_find_entry(struct inode * dir,
24 const char * name, int namelen, struct bfs_dirent ** res_dir);
25
26static int bfs_readdir(struct file * f, void * dirent, filldir_t filldir)
27{
28 struct inode * dir = f->f_dentry->d_inode;
29 struct buffer_head * bh;
30 struct bfs_dirent * de;
31 kdev_t dev = dir->i_dev;
32 unsigned int offset;
33 int block;
34
35 if (f->f_pos & (BFS_DIRENT_SIZE-1)) {
36 printf("Bad f_pos=%08lx for %s:%08lx\n", (unsigned long)f->f_pos,
37 bdevname(dev), dir->i_ino);
38 return -EBADF;
39 }
40
41 while (f->f_pos < dir->i_size) {
42 offset = f->f_pos & (BFS_BSIZE-1);
43 block = dir->iu_sblock + (f->f_pos >> BFS_BSIZE_BITS);
44 bh = sb_bread(dir->i_sb, block);
45 if (!bh) {
46 f->f_pos += BFS_BSIZE - offset;
47 continue;
48 }
49 do {
50 de = (struct bfs_dirent *)(bh->b_data + offset);
51 if (de->ino) {
52 int size = strnlen(de->name, BFS_NAMELEN);
53 if (filldir(dirent, de->name, size, f->f_pos, de->ino, DT_UNKNOWN) < 0) {
54 brelse(bh);
55 return 0;
56 }
57 }
58 offset += BFS_DIRENT_SIZE;
59 f->f_pos += BFS_DIRENT_SIZE;
60 } while (offset < BFS_BSIZE && f->f_pos < dir->i_size);
61 brelse(bh);
62 }
63
64 UPDATE_ATIME(dir);
65 return 0;
66}
67
68struct file_operations bfs_dir_operations = {
69 read: generic_read_dir,
70 readdir: bfs_readdir,
71 fsync: file_fsync,
72};
73
74extern void dump_imap(const char *, struct super_block *);
75
76static int bfs_create(struct inode * dir, struct dentry * dentry, int mode)
77{
78 int err;
79 struct inode * inode;
80 struct super_block * s = dir->i_sb;
81 unsigned long ino;
82
83 inode = new_inode(s);
84 if (!inode)
85 return -ENOSPC;
86 ino = find_first_zero_bit(s->su_imap, s->su_lasti);
87 if (ino > s->su_lasti) {
88 iput(inode);
89 return -ENOSPC;
90 }
91 set_bit(ino, s->su_imap);
92 s->su_freei--;
93 inode->i_uid = current->fsuid;
94 inode->i_gid = (dir->i_mode & S_ISGID) ? dir->i_gid : current->fsgid;
95 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
96 inode->i_blocks = inode->i_blksize = 0;
97 inode->i_op = &bfs_file_inops;
98 inode->i_fop = &bfs_file_operations;
99 inode->i_mapping->a_ops = &bfs_aops;
100 inode->i_mode = mode;
101 inode->i_ino = inode->iu_dsk_ino = ino;
102 inode->iu_sblock = inode->iu_eblock = 0;
103 insert_inode_hash(inode);
104 mark_inode_dirty(inode);
105 dump_imap("create",s);
106
107 err = bfs_add_entry(dir, dentry->d_name.name, dentry->d_name.len, inode->i_ino);
108 if (err) {
109 inode->i_nlink--;
110 mark_inode_dirty(inode);
111 iput(inode);
112 return err;
113 }
114 d_instantiate(dentry, inode);
115 return 0;
116}
117
118static struct dentry * bfs_lookup(struct inode * dir, struct dentry * dentry)
119{
120 struct inode * inode = NULL;
121 struct buffer_head * bh;
122 struct bfs_dirent * de;
123
124 if (dentry->d_name.len > BFS_NAMELEN)
125 return ERR_PTR(-ENAMETOOLONG);
126
127 bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
128 if (bh) {
129 unsigned long ino = le32_to_cpu(de->ino);
130 brelse(bh);
131 inode = iget(dir->i_sb, ino);
132 if (!inode)
133 return ERR_PTR(-EACCES);
134 }
135 d_add(dentry, inode);
136 return NULL;
137}
138
139static int bfs_link(struct dentry * old, struct inode * dir, struct dentry * new)
140{
141 struct inode * inode = old->d_inode;
142 int err;
143
144 if (S_ISDIR(inode->i_mode))
145 return -EPERM;
146
147 err = bfs_add_entry(dir, new->d_name.name, new->d_name.len, inode->i_ino);
148 if (err)
149 return err;
150 inode->i_nlink++;
151 inode->i_ctime = CURRENT_TIME;
152 mark_inode_dirty(inode);
153 atomic_inc(&inode->i_count);
154 d_instantiate(new, inode);
155 return 0;
156}
157
158
159static int bfs_unlink(struct inode * dir, struct dentry * dentry)
160{
161 int error = -ENOENT;
162 struct inode * inode;
163 struct buffer_head * bh;
164 struct bfs_dirent * de;
165
166 inode = dentry->d_inode;
167 bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
168 if (!bh || de->ino != inode->i_ino)
169 goto out_brelse;
170
171 if (!inode->i_nlink) {
172 printf("unlinking non-existent file %s:%lu (nlink=%d)\n", bdevname(inode->i_dev),
173 inode->i_ino, inode->i_nlink);
174 inode->i_nlink = 1;
175 }
176 de->ino = 0;
177 dir->i_version = ++event;
178 mark_buffer_dirty(bh);
179 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
180 mark_inode_dirty(dir);
181 inode->i_nlink--;
182 inode->i_ctime = dir->i_ctime;
183 mark_inode_dirty(inode);
184 error = 0;
185
186out_brelse:
187 brelse(bh);
188 return error;
189}
190
191static int bfs_rename(struct inode * old_dir, struct dentry * old_dentry,
192 struct inode * new_dir, struct dentry * new_dentry)
193{
194 struct inode * old_inode, * new_inode;
195 struct buffer_head * old_bh, * new_bh;
196 struct bfs_dirent * old_de, * new_de;
197 int error = -ENOENT;
198
199 old_bh = new_bh = NULL;
200 old_inode = old_dentry->d_inode;
201 if (S_ISDIR(old_inode->i_mode))
202 return -EINVAL;
203
204 old_bh = bfs_find_entry(old_dir,
205 old_dentry->d_name.name,
206 old_dentry->d_name.len, &old_de);
207
208 if (!old_bh || old_de->ino != old_inode->i_ino)
209 goto end_rename;
210
211 error = -EPERM;
212 new_inode = new_dentry->d_inode;
213 new_bh = bfs_find_entry(new_dir,
214 new_dentry->d_name.name,
215 new_dentry->d_name.len, &new_de);
216
217 if (new_bh && !new_inode) {
218 brelse(new_bh);
219 new_bh = NULL;
220 }
221 if (!new_bh) {
222 error = bfs_add_entry(new_dir,
223 new_dentry->d_name.name,
224 new_dentry->d_name.len, old_inode->i_ino);
225 if (error)
226 goto end_rename;
227 }
228 old_de->ino = 0;
229 old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME;
230 old_dir->i_version = ++event;
231 mark_inode_dirty(old_dir);
232 if (new_inode) {
233 new_inode->i_nlink--;
234 new_inode->i_ctime = CURRENT_TIME;
235 mark_inode_dirty(new_inode);
236 }
237 mark_buffer_dirty(old_bh);
238 error = 0;
239
240end_rename:
241 brelse(old_bh);
242 brelse(new_bh);
243 return error;
244}
245
246struct inode_operations bfs_dir_inops = {
247 create: bfs_create,
248 lookup: bfs_lookup,
249 link: bfs_link,
250 unlink: bfs_unlink,
251 rename: bfs_rename,
252};
253
254static int bfs_add_entry(struct inode * dir, const char * name, int namelen, int ino)
255{
256 struct buffer_head * bh;
257 struct bfs_dirent * de;
258 int block, sblock, eblock, off;
259 int i;
260
261 dprintf("name=%s, namelen=%d\n", name, namelen);
262
263 if (!namelen)
264 return -ENOENT;
265 if (namelen > BFS_NAMELEN)
266 return -ENAMETOOLONG;
267
268 sblock = dir->iu_sblock;
269 eblock = dir->iu_eblock;
270 for (block=sblock; block<=eblock; block++) {
271 bh = sb_bread(dir->i_sb, block);
272 if(!bh)
273 return -ENOSPC;
274 for (off=0; off<BFS_BSIZE; off+=BFS_DIRENT_SIZE) {
275 de = (struct bfs_dirent *)(bh->b_data + off);
276 if (!de->ino) {
277 if ((block-sblock)*BFS_BSIZE + off >= dir->i_size) {
278 dir->i_size += BFS_DIRENT_SIZE;
279 dir->i_ctime = CURRENT_TIME;
280 }
281 dir->i_mtime = CURRENT_TIME;
282 mark_inode_dirty(dir);
283 dir->i_version = ++event;
284 de->ino = ino;
285 for (i=0; i<BFS_NAMELEN; i++)
286 de->name[i] = (i < namelen) ? name[i] : 0;
287 mark_buffer_dirty(bh);
288 brelse(bh);
289 return 0;
290 }
291 }
292 brelse(bh);
293 }
294 return -ENOSPC;
295}
296
297static inline int bfs_namecmp(int len, const char * name, const char * buffer)
298{
299 if (len < BFS_NAMELEN && buffer[len])
300 return 0;
301 return !memcmp(name, buffer, len);
302}
303
304static struct buffer_head * bfs_find_entry(struct inode * dir,
305 const char * name, int namelen, struct bfs_dirent ** res_dir)
306{
307 unsigned long block, offset;
308 struct buffer_head * bh;
309 struct bfs_dirent * de;
310
311 *res_dir = NULL;
312 if (namelen > BFS_NAMELEN)
313 return NULL;
314 bh = NULL;
315 block = offset = 0;
316 while (block * BFS_BSIZE + offset < dir->i_size) {
317 if (!bh) {
318 bh = sb_bread(dir->i_sb, dir->iu_sblock + block);
319 if (!bh) {
320 block++;
321 continue;
322 }
323 }
324 de = (struct bfs_dirent *)(bh->b_data + offset);
325 offset += BFS_DIRENT_SIZE;
326 if (de->ino && bfs_namecmp(namelen, name, de->name)) {
327 *res_dir = de;
328 return bh;
329 }
330 if (offset < bh->b_size)
331 continue;
332 brelse(bh);
333 bh = NULL;
334 offset = 0;
335 block++;
336 }
337 brelse(bh);
338 return NULL;
339}
340
