File: /usr/src/linux/fs/bfs/dir.c
1 /*
2 * fs/bfs/dir.c
3 * BFS directory operations.
4 * Copyright (C) 1999,2000 Tigran Aivazian <tigran@veritas.com>
5 */
6
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
22 static int bfs_add_entry(struct inode * dir, const char * name, int namelen, int ino);
23 static struct buffer_head * bfs_find_entry(struct inode * dir,
24 const char * name, int namelen, struct bfs_dirent ** res_dir);
25
26 static 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 = bread(dev, block, BFS_BSIZE);
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
68 struct file_operations bfs_dir_operations = {
69 read: generic_read_dir,
70 readdir: bfs_readdir,
71 fsync: file_fsync,
72 };
73
74 extern void dump_imap(const char *, struct super_block *);
75
76 static 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
118 static 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
139 static 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
159 static 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
186 out_brelse:
187 brelse(bh);
188 return error;
189 }
190
191 static 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
240 end_rename:
241 brelse(old_bh);
242 brelse(new_bh);
243 return error;
244 }
245
246 struct 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
254 static 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 kdev_t dev;
260 int i;
261
262 dprintf("name=%s, namelen=%d\n", name, namelen);
263
264 if (!namelen)
265 return -ENOENT;
266 if (namelen > BFS_NAMELEN)
267 return -ENAMETOOLONG;
268
269 dev = dir->i_dev;
270 sblock = dir->iu_sblock;
271 eblock = dir->iu_eblock;
272 for (block=sblock; block<=eblock; block++) {
273 bh = bread(dev, block, BFS_BSIZE);
274 if(!bh)
275 return -ENOSPC;
276 for (off=0; off<BFS_BSIZE; off+=BFS_DIRENT_SIZE) {
277 de = (struct bfs_dirent *)(bh->b_data + off);
278 if (!de->ino) {
279 if ((block-sblock)*BFS_BSIZE + off >= dir->i_size) {
280 dir->i_size += BFS_DIRENT_SIZE;
281 dir->i_ctime = CURRENT_TIME;
282 }
283 dir->i_mtime = CURRENT_TIME;
284 mark_inode_dirty(dir);
285 dir->i_version = ++event;
286 de->ino = ino;
287 for (i=0; i<BFS_NAMELEN; i++)
288 de->name[i] = (i < namelen) ? name[i] : 0;
289 mark_buffer_dirty(bh);
290 brelse(bh);
291 return 0;
292 }
293 }
294 brelse(bh);
295 }
296 return -ENOSPC;
297 }
298
299 static inline int bfs_namecmp(int len, const char * name, const char * buffer)
300 {
301 if (len < BFS_NAMELEN && buffer[len])
302 return 0;
303 return !memcmp(name, buffer, len);
304 }
305
306 static struct buffer_head * bfs_find_entry(struct inode * dir,
307 const char * name, int namelen, struct bfs_dirent ** res_dir)
308 {
309 unsigned long block, offset;
310 struct buffer_head * bh;
311 struct bfs_sb_info * info;
312 struct bfs_dirent * de;
313
314 *res_dir = NULL;
315 info = &dir->i_sb->u.bfs_sb;
316 if (namelen > BFS_NAMELEN)
317 return NULL;
318 bh = NULL;
319 block = offset = 0;
320 while (block * BFS_BSIZE + offset < dir->i_size) {
321 if (!bh) {
322 bh = bread(dir->i_dev, dir->iu_sblock + block, BFS_BSIZE);
323 if (!bh) {
324 block++;
325 continue;
326 }
327 }
328 de = (struct bfs_dirent *)(bh->b_data + offset);
329 offset += BFS_DIRENT_SIZE;
330 if (de->ino && bfs_namecmp(namelen, name, de->name)) {
331 *res_dir = de;
332 return bh;
333 }
334 if (offset < bh->b_size)
335 continue;
336 brelse(bh);
337 bh = NULL;
338 offset = 0;
339 block++;
340 }
341 brelse(bh);
342 return NULL;
343 }
344