xref: /openbmc/linux/fs/bfs/dir.c (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
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_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 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 = inode->i_blksize = 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->i_nlink--;
121 		mark_inode_dirty(inode);
122 		iput(inode);
123 		unlock_kernel();
124 		return err;
125 	}
126 	unlock_kernel();
127 	d_instantiate(dentry, inode);
128 	return 0;
129 }
130 
131 static struct dentry * bfs_lookup(struct inode * dir, struct dentry * dentry, struct nameidata *nd)
132 {
133 	struct inode * inode = NULL;
134 	struct buffer_head * bh;
135 	struct bfs_dirent * de;
136 
137 	if (dentry->d_name.len > BFS_NAMELEN)
138 		return ERR_PTR(-ENAMETOOLONG);
139 
140 	lock_kernel();
141 	bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
142 	if (bh) {
143 		unsigned long ino = (unsigned long)le16_to_cpu(de->ino);
144 		brelse(bh);
145 		inode = iget(dir->i_sb, ino);
146 		if (!inode) {
147 			unlock_kernel();
148 			return ERR_PTR(-EACCES);
149 		}
150 	}
151 	unlock_kernel();
152 	d_add(dentry, inode);
153 	return NULL;
154 }
155 
156 static int bfs_link(struct dentry * old, struct inode * dir, struct dentry * new)
157 {
158 	struct inode * inode = old->d_inode;
159 	int err;
160 
161 	lock_kernel();
162 	err = bfs_add_entry(dir, new->d_name.name, new->d_name.len, inode->i_ino);
163 	if (err) {
164 		unlock_kernel();
165 		return err;
166 	}
167 	inode->i_nlink++;
168 	inode->i_ctime = CURRENT_TIME_SEC;
169 	mark_inode_dirty(inode);
170 	atomic_inc(&inode->i_count);
171 	d_instantiate(new, inode);
172 	unlock_kernel();
173 	return 0;
174 }
175 
176 
177 static int bfs_unlink(struct inode * dir, struct dentry * dentry)
178 {
179 	int error = -ENOENT;
180 	struct inode * inode;
181 	struct buffer_head * bh;
182 	struct bfs_dirent * de;
183 
184 	inode = dentry->d_inode;
185 	lock_kernel();
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", inode->i_sb->s_id,
192 				inode->i_ino, inode->i_nlink);
193 		inode->i_nlink = 1;
194 	}
195 	de->ino = 0;
196 	mark_buffer_dirty(bh);
197 	dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
198 	mark_inode_dirty(dir);
199 	inode->i_nlink--;
200 	inode->i_ctime = dir->i_ctime;
201 	mark_inode_dirty(inode);
202 	error = 0;
203 
204 out_brelse:
205 	brelse(bh);
206 	unlock_kernel();
207 	return error;
208 }
209 
210 static int bfs_rename(struct inode * old_dir, struct dentry * old_dentry,
211 			struct inode * new_dir, struct dentry * new_dentry)
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 	int error = -ENOENT;
217 
218 	old_bh = new_bh = NULL;
219 	old_inode = old_dentry->d_inode;
220 	if (S_ISDIR(old_inode->i_mode))
221 		return -EINVAL;
222 
223 	lock_kernel();
224 	old_bh = bfs_find_entry(old_dir,
225 				old_dentry->d_name.name,
226 				old_dentry->d_name.len, &old_de);
227 
228 	if (!old_bh || le16_to_cpu(old_de->ino) != old_inode->i_ino)
229 		goto end_rename;
230 
231 	error = -EPERM;
232 	new_inode = new_dentry->d_inode;
233 	new_bh = bfs_find_entry(new_dir,
234 				new_dentry->d_name.name,
235 				new_dentry->d_name.len, &new_de);
236 
237 	if (new_bh && !new_inode) {
238 		brelse(new_bh);
239 		new_bh = NULL;
240 	}
241 	if (!new_bh) {
242 		error = bfs_add_entry(new_dir,
243 					new_dentry->d_name.name,
244 			 		new_dentry->d_name.len, old_inode->i_ino);
245 		if (error)
246 			goto end_rename;
247 	}
248 	old_de->ino = 0;
249 	old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
250 	mark_inode_dirty(old_dir);
251 	if (new_inode) {
252 		new_inode->i_nlink--;
253 		new_inode->i_ctime = CURRENT_TIME_SEC;
254 		mark_inode_dirty(new_inode);
255 	}
256 	mark_buffer_dirty(old_bh);
257 	error = 0;
258 
259 end_rename:
260 	unlock_kernel();
261 	brelse(old_bh);
262 	brelse(new_bh);
263 	return error;
264 }
265 
266 struct inode_operations bfs_dir_inops = {
267 	.create			= bfs_create,
268 	.lookup			= bfs_lookup,
269 	.link			= bfs_link,
270 	.unlink			= bfs_unlink,
271 	.rename			= bfs_rename,
272 };
273 
274 static int bfs_add_entry(struct inode * dir, const unsigned char * name, int namelen, int ino)
275 {
276 	struct buffer_head * bh;
277 	struct bfs_dirent * de;
278 	int block, sblock, eblock, off, eoff;
279 	int i;
280 
281 	dprintf("name=%s, namelen=%d\n", name, namelen);
282 
283 	if (!namelen)
284 		return -ENOENT;
285 	if (namelen > BFS_NAMELEN)
286 		return -ENAMETOOLONG;
287 
288 	sblock = BFS_I(dir)->i_sblock;
289 	eblock = BFS_I(dir)->i_eblock;
290 	eoff = dir->i_size % BFS_BSIZE;
291 	for (block=sblock; block<=eblock; block++) {
292 		bh = sb_bread(dir->i_sb, block);
293 		if(!bh)
294 			return -ENOSPC;
295 		for (off=0; off<BFS_BSIZE; off+=BFS_DIRENT_SIZE) {
296 			de = (struct bfs_dirent *)(bh->b_data + off);
297 			if (block==eblock && off>=eoff) {
298 				/* Do not read/interpret the garbage in the end of eblock. */
299 				de->ino = 0;
300 			}
301 			if (!de->ino) {
302 				if ((block-sblock)*BFS_BSIZE + off >= dir->i_size) {
303 					dir->i_size += BFS_DIRENT_SIZE;
304 					dir->i_ctime = CURRENT_TIME_SEC;
305 				}
306 				dir->i_mtime = CURRENT_TIME_SEC;
307 				mark_inode_dirty(dir);
308 				de->ino = cpu_to_le16((u16)ino);
309 				for (i=0; i<BFS_NAMELEN; i++)
310 					de->name[i] = (i < namelen) ? name[i] : 0;
311 				mark_buffer_dirty(bh);
312 				brelse(bh);
313 				return 0;
314 			}
315 		}
316 		brelse(bh);
317 	}
318 	return -ENOSPC;
319 }
320 
321 static inline int bfs_namecmp(int len, const unsigned char * name, const char * buffer)
322 {
323 	if (len < BFS_NAMELEN && buffer[len])
324 		return 0;
325 	return !memcmp(name, buffer, len);
326 }
327 
328 static struct buffer_head * bfs_find_entry(struct inode * dir,
329 	const unsigned char * name, int namelen, struct bfs_dirent ** res_dir)
330 {
331 	unsigned long block, offset;
332 	struct buffer_head * bh;
333 	struct bfs_dirent * de;
334 
335 	*res_dir = NULL;
336 	if (namelen > BFS_NAMELEN)
337 		return NULL;
338 	bh = NULL;
339 	block = offset = 0;
340 	while (block * BFS_BSIZE + offset < dir->i_size) {
341 		if (!bh) {
342 			bh = sb_bread(dir->i_sb, BFS_I(dir)->i_sblock + block);
343 			if (!bh) {
344 				block++;
345 				continue;
346 			}
347 		}
348 		de = (struct bfs_dirent *)(bh->b_data + offset);
349 		offset += BFS_DIRENT_SIZE;
350 		if (le16_to_cpu(de->ino) && bfs_namecmp(namelen, name, de->name)) {
351 			*res_dir = de;
352 			return bh;
353 		}
354 		if (offset < bh->b_size)
355 			continue;
356 		brelse(bh);
357 		bh = NULL;
358 		offset = 0;
359 		block++;
360 	}
361 	brelse(bh);
362 	return NULL;
363 }
364