xref: /openbmc/linux/fs/bfs/dir.c (revision e868d61272caa648214046a096e5a6bfc068dc8c)
1 /*
2  *	fs/bfs/dir.c
3  *	BFS directory operations.
4  *	Copyright (C) 1999,2000  Tigran Aivazian <tigran@veritas.com>
5  *      Made endianness-clean by Andrew Stribblehill <ads@wompom.org> 2005
6  */
7 
8 #include <linux/time.h>
9 #include <linux/string.h>
10 #include <linux/fs.h>
11 #include <linux/smp_lock.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 
24 static int bfs_add_entry(struct inode * dir, const unsigned char * name, int namelen, int ino);
25 static struct buffer_head * bfs_find_entry(struct inode * dir,
26 	const unsigned char * name, int namelen, struct bfs_dirent ** res_dir);
27 
28 static int bfs_readdir(struct file * f, void * dirent, filldir_t filldir)
29 {
30 	struct inode * dir = f->f_path.dentry->d_inode;
31 	struct buffer_head * bh;
32 	struct bfs_dirent * de;
33 	unsigned int offset;
34 	int block;
35 
36 	lock_kernel();
37 
38 	if (f->f_pos & (BFS_DIRENT_SIZE-1)) {
39 		printf("Bad f_pos=%08lx for %s:%08lx\n", (unsigned long)f->f_pos,
40 			dir->i_sb->s_id, dir->i_ino);
41 		unlock_kernel();
42 		return -EBADF;
43 	}
44 
45 	while (f->f_pos < dir->i_size) {
46 		offset = f->f_pos & (BFS_BSIZE-1);
47 		block = BFS_I(dir)->i_sblock + (f->f_pos >> BFS_BSIZE_BITS);
48 		bh = sb_bread(dir->i_sb, block);
49 		if (!bh) {
50 			f->f_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 (filldir(dirent, de->name, size, f->f_pos, le16_to_cpu(de->ino), DT_UNKNOWN) < 0) {
58 					brelse(bh);
59 					unlock_kernel();
60 					return 0;
61 				}
62 			}
63 			offset += BFS_DIRENT_SIZE;
64 			f->f_pos += BFS_DIRENT_SIZE;
65 		} while (offset < BFS_BSIZE && f->f_pos < dir->i_size);
66 		brelse(bh);
67 	}
68 
69 	unlock_kernel();
70 	return 0;
71 }
72 
73 const struct file_operations bfs_dir_operations = {
74 	.read		= generic_read_dir,
75 	.readdir	= bfs_readdir,
76 	.fsync		= file_fsync,
77 };
78 
79 extern void dump_imap(const char *, struct super_block *);
80 
81 static int bfs_create(struct inode * dir, struct dentry * dentry, int mode,
82 		struct nameidata *nd)
83 {
84 	int err;
85 	struct inode * inode;
86 	struct super_block * s = dir->i_sb;
87 	struct bfs_sb_info * info = BFS_SB(s);
88 	unsigned long ino;
89 
90 	inode = new_inode(s);
91 	if (!inode)
92 		return -ENOSPC;
93 	lock_kernel();
94 	ino = find_first_zero_bit(info->si_imap, info->si_lasti);
95 	if (ino > info->si_lasti) {
96 		unlock_kernel();
97 		iput(inode);
98 		return -ENOSPC;
99 	}
100 	set_bit(ino, info->si_imap);
101 	info->si_freei--;
102 	inode->i_uid = current->fsuid;
103 	inode->i_gid = (dir->i_mode & S_ISGID) ? dir->i_gid : current->fsgid;
104 	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
105 	inode->i_blocks = 0;
106 	inode->i_op = &bfs_file_inops;
107 	inode->i_fop = &bfs_file_operations;
108 	inode->i_mapping->a_ops = &bfs_aops;
109 	inode->i_mode = mode;
110 	inode->i_ino = ino;
111 	BFS_I(inode)->i_dsk_ino = ino;
112 	BFS_I(inode)->i_sblock = 0;
113 	BFS_I(inode)->i_eblock = 0;
114 	insert_inode_hash(inode);
115         mark_inode_dirty(inode);
116 	dump_imap("create",s);
117 
118 	err = bfs_add_entry(dir, dentry->d_name.name, dentry->d_name.len, inode->i_ino);
119 	if (err) {
120 		inode_dec_link_count(inode);
121 		iput(inode);
122 		unlock_kernel();
123 		return err;
124 	}
125 	unlock_kernel();
126 	d_instantiate(dentry, inode);
127 	return 0;
128 }
129 
130 static struct dentry * bfs_lookup(struct inode * dir, struct dentry * dentry, struct nameidata *nd)
131 {
132 	struct inode * inode = NULL;
133 	struct buffer_head * bh;
134 	struct bfs_dirent * de;
135 
136 	if (dentry->d_name.len > BFS_NAMELEN)
137 		return ERR_PTR(-ENAMETOOLONG);
138 
139 	lock_kernel();
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 = iget(dir->i_sb, ino);
145 		if (!inode) {
146 			unlock_kernel();
147 			return ERR_PTR(-EACCES);
148 		}
149 	}
150 	unlock_kernel();
151 	d_add(dentry, inode);
152 	return NULL;
153 }
154 
155 static int bfs_link(struct dentry * old, struct inode * dir, struct dentry * new)
156 {
157 	struct inode * inode = old->d_inode;
158 	int err;
159 
160 	lock_kernel();
161 	err = bfs_add_entry(dir, new->d_name.name, new->d_name.len, inode->i_ino);
162 	if (err) {
163 		unlock_kernel();
164 		return err;
165 	}
166 	inc_nlink(inode);
167 	inode->i_ctime = CURRENT_TIME_SEC;
168 	mark_inode_dirty(inode);
169 	atomic_inc(&inode->i_count);
170 	d_instantiate(new, inode);
171 	unlock_kernel();
172 	return 0;
173 }
174 
175 
176 static int bfs_unlink(struct inode * dir, struct dentry * dentry)
177 {
178 	int error = -ENOENT;
179 	struct inode * inode;
180 	struct buffer_head * bh;
181 	struct bfs_dirent * de;
182 
183 	inode = dentry->d_inode;
184 	lock_kernel();
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", inode->i_sb->s_id,
191 				inode->i_ino, inode->i_nlink);
192 		inode->i_nlink = 1;
193 	}
194 	de->ino = 0;
195 	mark_buffer_dirty(bh);
196 	dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
197 	mark_inode_dirty(dir);
198 	inode->i_ctime = dir->i_ctime;
199 	inode_dec_link_count(inode);
200 	error = 0;
201 
202 out_brelse:
203 	brelse(bh);
204 	unlock_kernel();
205 	return error;
206 }
207 
208 static int bfs_rename(struct inode * old_dir, struct dentry * old_dentry,
209 			struct inode * new_dir, struct dentry * new_dentry)
210 {
211 	struct inode * old_inode, * new_inode;
212 	struct buffer_head * old_bh, * new_bh;
213 	struct bfs_dirent * old_de, * new_de;
214 	int error = -ENOENT;
215 
216 	old_bh = new_bh = NULL;
217 	old_inode = old_dentry->d_inode;
218 	if (S_ISDIR(old_inode->i_mode))
219 		return -EINVAL;
220 
221 	lock_kernel();
222 	old_bh = bfs_find_entry(old_dir,
223 				old_dentry->d_name.name,
224 				old_dentry->d_name.len, &old_de);
225 
226 	if (!old_bh || le16_to_cpu(old_de->ino) != old_inode->i_ino)
227 		goto end_rename;
228 
229 	error = -EPERM;
230 	new_inode = new_dentry->d_inode;
231 	new_bh = bfs_find_entry(new_dir,
232 				new_dentry->d_name.name,
233 				new_dentry->d_name.len, &new_de);
234 
235 	if (new_bh && !new_inode) {
236 		brelse(new_bh);
237 		new_bh = NULL;
238 	}
239 	if (!new_bh) {
240 		error = bfs_add_entry(new_dir,
241 					new_dentry->d_name.name,
242 			 		new_dentry->d_name.len, old_inode->i_ino);
243 		if (error)
244 			goto end_rename;
245 	}
246 	old_de->ino = 0;
247 	old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
248 	mark_inode_dirty(old_dir);
249 	if (new_inode) {
250 		new_inode->i_ctime = CURRENT_TIME_SEC;
251 		inode_dec_link_count(new_inode);
252 	}
253 	mark_buffer_dirty(old_bh);
254 	error = 0;
255 
256 end_rename:
257 	unlock_kernel();
258 	brelse(old_bh);
259 	brelse(new_bh);
260 	return error;
261 }
262 
263 const struct inode_operations bfs_dir_inops = {
264 	.create			= bfs_create,
265 	.lookup			= bfs_lookup,
266 	.link			= bfs_link,
267 	.unlink			= bfs_unlink,
268 	.rename			= bfs_rename,
269 };
270 
271 static int bfs_add_entry(struct inode * dir, const unsigned char * name, int namelen, int ino)
272 {
273 	struct buffer_head * bh;
274 	struct bfs_dirent * de;
275 	int block, sblock, eblock, off, eoff;
276 	int i;
277 
278 	dprintf("name=%s, namelen=%d\n", name, namelen);
279 
280 	if (!namelen)
281 		return -ENOENT;
282 	if (namelen > BFS_NAMELEN)
283 		return -ENAMETOOLONG;
284 
285 	sblock = BFS_I(dir)->i_sblock;
286 	eblock = BFS_I(dir)->i_eblock;
287 	eoff = dir->i_size % BFS_BSIZE;
288 	for (block=sblock; block<=eblock; block++) {
289 		bh = sb_bread(dir->i_sb, block);
290 		if(!bh)
291 			return -ENOSPC;
292 		for (off=0; off<BFS_BSIZE; off+=BFS_DIRENT_SIZE) {
293 			de = (struct bfs_dirent *)(bh->b_data + off);
294 			if (block==eblock && off>=eoff) {
295 				/* Do not read/interpret the garbage in the end of eblock. */
296 				de->ino = 0;
297 			}
298 			if (!de->ino) {
299 				if ((block-sblock)*BFS_BSIZE + off >= dir->i_size) {
300 					dir->i_size += BFS_DIRENT_SIZE;
301 					dir->i_ctime = CURRENT_TIME_SEC;
302 				}
303 				dir->i_mtime = CURRENT_TIME_SEC;
304 				mark_inode_dirty(dir);
305 				de->ino = cpu_to_le16((u16)ino);
306 				for (i=0; i<BFS_NAMELEN; i++)
307 					de->name[i] = (i < namelen) ? name[i] : 0;
308 				mark_buffer_dirty(bh);
309 				brelse(bh);
310 				return 0;
311 			}
312 		}
313 		brelse(bh);
314 	}
315 	return -ENOSPC;
316 }
317 
318 static inline int bfs_namecmp(int len, const unsigned char * name, const char * buffer)
319 {
320 	if (len < BFS_NAMELEN && buffer[len])
321 		return 0;
322 	return !memcmp(name, buffer, len);
323 }
324 
325 static struct buffer_head * bfs_find_entry(struct inode * dir,
326 	const unsigned char * name, int namelen, struct bfs_dirent ** res_dir)
327 {
328 	unsigned long block, offset;
329 	struct buffer_head * bh;
330 	struct bfs_dirent * de;
331 
332 	*res_dir = NULL;
333 	if (namelen > BFS_NAMELEN)
334 		return NULL;
335 	bh = NULL;
336 	block = offset = 0;
337 	while (block * BFS_BSIZE + offset < dir->i_size) {
338 		if (!bh) {
339 			bh = sb_bread(dir->i_sb, BFS_I(dir)->i_sblock + block);
340 			if (!bh) {
341 				block++;
342 				continue;
343 			}
344 		}
345 		de = (struct bfs_dirent *)(bh->b_data + offset);
346 		offset += BFS_DIRENT_SIZE;
347 		if (le16_to_cpu(de->ino) && bfs_namecmp(namelen, name, de->name)) {
348 			*res_dir = de;
349 			return bh;
350 		}
351 		if (offset < bh->b_size)
352 			continue;
353 		brelse(bh);
354 		bh = NULL;
355 		offset = 0;
356 		block++;
357 	}
358 	brelse(bh);
359 	return NULL;
360 }
361