xref: /openbmc/linux/fs/qnx4/inode.c (revision 0edbfea5)
1 /*
2  * QNX4 file system, Linux implementation.
3  *
4  * Version : 0.2.1
5  *
6  * Using parts of the xiafs filesystem.
7  *
8  * History :
9  *
10  * 01-06-1998 by Richard Frowijn : first release.
11  * 20-06-1998 by Frank Denis : Linux 2.1.99+ support, boot signature, misc.
12  * 30-06-1998 by Frank Denis : first step to write inodes.
13  */
14 
15 #include <linux/module.h>
16 #include <linux/init.h>
17 #include <linux/slab.h>
18 #include <linux/highuid.h>
19 #include <linux/pagemap.h>
20 #include <linux/buffer_head.h>
21 #include <linux/writeback.h>
22 #include <linux/statfs.h>
23 #include "qnx4.h"
24 
25 #define QNX4_VERSION  4
26 #define QNX4_BMNAME   ".bitmap"
27 
28 static const struct super_operations qnx4_sops;
29 
30 static struct inode *qnx4_alloc_inode(struct super_block *sb);
31 static void qnx4_destroy_inode(struct inode *inode);
32 static int qnx4_remount(struct super_block *sb, int *flags, char *data);
33 static int qnx4_statfs(struct dentry *, struct kstatfs *);
34 
35 static const struct super_operations qnx4_sops =
36 {
37 	.alloc_inode	= qnx4_alloc_inode,
38 	.destroy_inode	= qnx4_destroy_inode,
39 	.statfs		= qnx4_statfs,
40 	.remount_fs	= qnx4_remount,
41 };
42 
43 static int qnx4_remount(struct super_block *sb, int *flags, char *data)
44 {
45 	struct qnx4_sb_info *qs;
46 
47 	sync_filesystem(sb);
48 	qs = qnx4_sb(sb);
49 	qs->Version = QNX4_VERSION;
50 	*flags |= MS_RDONLY;
51 	return 0;
52 }
53 
54 static int qnx4_get_block( struct inode *inode, sector_t iblock, struct buffer_head *bh, int create )
55 {
56 	unsigned long phys;
57 
58 	QNX4DEBUG((KERN_INFO "qnx4: qnx4_get_block inode=[%ld] iblock=[%ld]\n",inode->i_ino,iblock));
59 
60 	phys = qnx4_block_map( inode, iblock );
61 	if ( phys ) {
62 		// logical block is before EOF
63 		map_bh(bh, inode->i_sb, phys);
64 	}
65 	return 0;
66 }
67 
68 static inline u32 try_extent(qnx4_xtnt_t *extent, u32 *offset)
69 {
70 	u32 size = le32_to_cpu(extent->xtnt_size);
71 	if (*offset < size)
72 		return le32_to_cpu(extent->xtnt_blk) + *offset - 1;
73 	*offset -= size;
74 	return 0;
75 }
76 
77 unsigned long qnx4_block_map( struct inode *inode, long iblock )
78 {
79 	int ix;
80 	long i_xblk;
81 	struct buffer_head *bh = NULL;
82 	struct qnx4_xblk *xblk = NULL;
83 	struct qnx4_inode_entry *qnx4_inode = qnx4_raw_inode(inode);
84 	u16 nxtnt = le16_to_cpu(qnx4_inode->di_num_xtnts);
85 	u32 offset = iblock;
86 	u32 block = try_extent(&qnx4_inode->di_first_xtnt, &offset);
87 
88 	if (block) {
89 		// iblock is in the first extent. This is easy.
90 	} else {
91 		// iblock is beyond first extent. We have to follow the extent chain.
92 		i_xblk = le32_to_cpu(qnx4_inode->di_xblk);
93 		ix = 0;
94 		while ( --nxtnt > 0 ) {
95 			if ( ix == 0 ) {
96 				// read next xtnt block.
97 				bh = sb_bread(inode->i_sb, i_xblk - 1);
98 				if ( !bh ) {
99 					QNX4DEBUG((KERN_ERR "qnx4: I/O error reading xtnt block [%ld])\n", i_xblk - 1));
100 					return -EIO;
101 				}
102 				xblk = (struct qnx4_xblk*)bh->b_data;
103 				if ( memcmp( xblk->xblk_signature, "IamXblk", 7 ) ) {
104 					QNX4DEBUG((KERN_ERR "qnx4: block at %ld is not a valid xtnt\n", qnx4_inode->i_xblk));
105 					return -EIO;
106 				}
107 			}
108 			block = try_extent(&xblk->xblk_xtnts[ix], &offset);
109 			if (block) {
110 				// got it!
111 				break;
112 			}
113 			if ( ++ix >= xblk->xblk_num_xtnts ) {
114 				i_xblk = le32_to_cpu(xblk->xblk_next_xblk);
115 				ix = 0;
116 				brelse( bh );
117 				bh = NULL;
118 			}
119 		}
120 		if ( bh )
121 			brelse( bh );
122 	}
123 
124 	QNX4DEBUG((KERN_INFO "qnx4: mapping block %ld of inode %ld = %ld\n",iblock,inode->i_ino,block));
125 	return block;
126 }
127 
128 static int qnx4_statfs(struct dentry *dentry, struct kstatfs *buf)
129 {
130 	struct super_block *sb = dentry->d_sb;
131 	u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
132 
133 	buf->f_type    = sb->s_magic;
134 	buf->f_bsize   = sb->s_blocksize;
135 	buf->f_blocks  = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size) * 8;
136 	buf->f_bfree   = qnx4_count_free_blocks(sb);
137 	buf->f_bavail  = buf->f_bfree;
138 	buf->f_namelen = QNX4_NAME_MAX;
139 	buf->f_fsid.val[0] = (u32)id;
140 	buf->f_fsid.val[1] = (u32)(id >> 32);
141 
142 	return 0;
143 }
144 
145 /*
146  * Check the root directory of the filesystem to make sure
147  * it really _is_ a qnx4 filesystem, and to check the size
148  * of the directory entry.
149  */
150 static const char *qnx4_checkroot(struct super_block *sb,
151 				  struct qnx4_super_block *s)
152 {
153 	struct buffer_head *bh;
154 	struct qnx4_inode_entry *rootdir;
155 	int rd, rl;
156 	int i, j;
157 
158 	if (s->RootDir.di_fname[0] != '/' || s->RootDir.di_fname[1] != '\0')
159 		return "no qnx4 filesystem (no root dir).";
160 	QNX4DEBUG((KERN_NOTICE "QNX4 filesystem found on dev %s.\n", sb->s_id));
161 	rd = le32_to_cpu(s->RootDir.di_first_xtnt.xtnt_blk) - 1;
162 	rl = le32_to_cpu(s->RootDir.di_first_xtnt.xtnt_size);
163 	for (j = 0; j < rl; j++) {
164 		bh = sb_bread(sb, rd + j);	/* root dir, first block */
165 		if (bh == NULL)
166 			return "unable to read root entry.";
167 		rootdir = (struct qnx4_inode_entry *) bh->b_data;
168 		for (i = 0; i < QNX4_INODES_PER_BLOCK; i++, rootdir++) {
169 			QNX4DEBUG((KERN_INFO "rootdir entry found : [%s]\n", rootdir->di_fname));
170 			if (strcmp(rootdir->di_fname, QNX4_BMNAME) != 0)
171 				continue;
172 			qnx4_sb(sb)->BitMap = kmemdup(rootdir,
173 						      sizeof(struct qnx4_inode_entry),
174 						      GFP_KERNEL);
175 			brelse(bh);
176 			if (!qnx4_sb(sb)->BitMap)
177 				return "not enough memory for bitmap inode";
178 			/* keep bitmap inode known */
179 			return NULL;
180 		}
181 		brelse(bh);
182 	}
183 	return "bitmap file not found.";
184 }
185 
186 static int qnx4_fill_super(struct super_block *s, void *data, int silent)
187 {
188 	struct buffer_head *bh;
189 	struct inode *root;
190 	const char *errmsg;
191 	struct qnx4_sb_info *qs;
192 
193 	qs = kzalloc(sizeof(struct qnx4_sb_info), GFP_KERNEL);
194 	if (!qs)
195 		return -ENOMEM;
196 	s->s_fs_info = qs;
197 
198 	sb_set_blocksize(s, QNX4_BLOCK_SIZE);
199 
200 	s->s_op = &qnx4_sops;
201 	s->s_magic = QNX4_SUPER_MAGIC;
202 	s->s_flags |= MS_RDONLY;	/* Yup, read-only yet */
203 
204 	/* Check the superblock signature. Since the qnx4 code is
205 	   dangerous, we should leave as quickly as possible
206 	   if we don't belong here... */
207 	bh = sb_bread(s, 1);
208 	if (!bh) {
209 		printk(KERN_ERR "qnx4: unable to read the superblock\n");
210 		return -EINVAL;
211 	}
212 
213  	/* check before allocating dentries, inodes, .. */
214 	errmsg = qnx4_checkroot(s, (struct qnx4_super_block *) bh->b_data);
215 	brelse(bh);
216 	if (errmsg != NULL) {
217  		if (!silent)
218 			printk(KERN_ERR "qnx4: %s\n", errmsg);
219 		return -EINVAL;
220 	}
221 
222  	/* does root not have inode number QNX4_ROOT_INO ?? */
223 	root = qnx4_iget(s, QNX4_ROOT_INO * QNX4_INODES_PER_BLOCK);
224 	if (IS_ERR(root)) {
225 		printk(KERN_ERR "qnx4: get inode failed\n");
226 		return PTR_ERR(root);
227  	}
228 
229  	s->s_root = d_make_root(root);
230  	if (s->s_root == NULL)
231  		return -ENOMEM;
232 
233 	return 0;
234 }
235 
236 static void qnx4_kill_sb(struct super_block *sb)
237 {
238 	struct qnx4_sb_info *qs = qnx4_sb(sb);
239 	kill_block_super(sb);
240 	if (qs) {
241 		kfree(qs->BitMap);
242 		kfree(qs);
243 	}
244 }
245 
246 static int qnx4_readpage(struct file *file, struct page *page)
247 {
248 	return block_read_full_page(page,qnx4_get_block);
249 }
250 
251 static sector_t qnx4_bmap(struct address_space *mapping, sector_t block)
252 {
253 	return generic_block_bmap(mapping,block,qnx4_get_block);
254 }
255 static const struct address_space_operations qnx4_aops = {
256 	.readpage	= qnx4_readpage,
257 	.bmap		= qnx4_bmap
258 };
259 
260 struct inode *qnx4_iget(struct super_block *sb, unsigned long ino)
261 {
262 	struct buffer_head *bh;
263 	struct qnx4_inode_entry *raw_inode;
264 	int block;
265 	struct qnx4_inode_entry *qnx4_inode;
266 	struct inode *inode;
267 
268 	inode = iget_locked(sb, ino);
269 	if (!inode)
270 		return ERR_PTR(-ENOMEM);
271 	if (!(inode->i_state & I_NEW))
272 		return inode;
273 
274 	qnx4_inode = qnx4_raw_inode(inode);
275 	inode->i_mode = 0;
276 
277 	QNX4DEBUG((KERN_INFO "reading inode : [%d]\n", ino));
278 	if (!ino) {
279 		printk(KERN_ERR "qnx4: bad inode number on dev %s: %lu is "
280 				"out of range\n",
281 		       sb->s_id, ino);
282 		iget_failed(inode);
283 		return ERR_PTR(-EIO);
284 	}
285 	block = ino / QNX4_INODES_PER_BLOCK;
286 
287 	if (!(bh = sb_bread(sb, block))) {
288 		printk(KERN_ERR "qnx4: major problem: unable to read inode from dev "
289 		       "%s\n", sb->s_id);
290 		iget_failed(inode);
291 		return ERR_PTR(-EIO);
292 	}
293 	raw_inode = ((struct qnx4_inode_entry *) bh->b_data) +
294 	    (ino % QNX4_INODES_PER_BLOCK);
295 
296 	inode->i_mode    = le16_to_cpu(raw_inode->di_mode);
297 	i_uid_write(inode, (uid_t)le16_to_cpu(raw_inode->di_uid));
298 	i_gid_write(inode, (gid_t)le16_to_cpu(raw_inode->di_gid));
299 	set_nlink(inode, le16_to_cpu(raw_inode->di_nlink));
300 	inode->i_size    = le32_to_cpu(raw_inode->di_size);
301 	inode->i_mtime.tv_sec   = le32_to_cpu(raw_inode->di_mtime);
302 	inode->i_mtime.tv_nsec = 0;
303 	inode->i_atime.tv_sec   = le32_to_cpu(raw_inode->di_atime);
304 	inode->i_atime.tv_nsec = 0;
305 	inode->i_ctime.tv_sec   = le32_to_cpu(raw_inode->di_ctime);
306 	inode->i_ctime.tv_nsec = 0;
307 	inode->i_blocks  = le32_to_cpu(raw_inode->di_first_xtnt.xtnt_size);
308 
309 	memcpy(qnx4_inode, raw_inode, QNX4_DIR_ENTRY_SIZE);
310 	if (S_ISREG(inode->i_mode)) {
311 		inode->i_fop = &generic_ro_fops;
312 		inode->i_mapping->a_ops = &qnx4_aops;
313 		qnx4_i(inode)->mmu_private = inode->i_size;
314 	} else if (S_ISDIR(inode->i_mode)) {
315 		inode->i_op = &qnx4_dir_inode_operations;
316 		inode->i_fop = &qnx4_dir_operations;
317 	} else if (S_ISLNK(inode->i_mode)) {
318 		inode->i_op = &page_symlink_inode_operations;
319 		inode_nohighmem(inode);
320 		inode->i_mapping->a_ops = &qnx4_aops;
321 		qnx4_i(inode)->mmu_private = inode->i_size;
322 	} else {
323 		printk(KERN_ERR "qnx4: bad inode %lu on dev %s\n",
324 			ino, sb->s_id);
325 		iget_failed(inode);
326 		brelse(bh);
327 		return ERR_PTR(-EIO);
328 	}
329 	brelse(bh);
330 	unlock_new_inode(inode);
331 	return inode;
332 }
333 
334 static struct kmem_cache *qnx4_inode_cachep;
335 
336 static struct inode *qnx4_alloc_inode(struct super_block *sb)
337 {
338 	struct qnx4_inode_info *ei;
339 	ei = kmem_cache_alloc(qnx4_inode_cachep, GFP_KERNEL);
340 	if (!ei)
341 		return NULL;
342 	return &ei->vfs_inode;
343 }
344 
345 static void qnx4_i_callback(struct rcu_head *head)
346 {
347 	struct inode *inode = container_of(head, struct inode, i_rcu);
348 	kmem_cache_free(qnx4_inode_cachep, qnx4_i(inode));
349 }
350 
351 static void qnx4_destroy_inode(struct inode *inode)
352 {
353 	call_rcu(&inode->i_rcu, qnx4_i_callback);
354 }
355 
356 static void init_once(void *foo)
357 {
358 	struct qnx4_inode_info *ei = (struct qnx4_inode_info *) foo;
359 
360 	inode_init_once(&ei->vfs_inode);
361 }
362 
363 static int init_inodecache(void)
364 {
365 	qnx4_inode_cachep = kmem_cache_create("qnx4_inode_cache",
366 					     sizeof(struct qnx4_inode_info),
367 					     0, (SLAB_RECLAIM_ACCOUNT|
368 						SLAB_MEM_SPREAD|SLAB_ACCOUNT),
369 					     init_once);
370 	if (qnx4_inode_cachep == NULL)
371 		return -ENOMEM;
372 	return 0;
373 }
374 
375 static void destroy_inodecache(void)
376 {
377 	/*
378 	 * Make sure all delayed rcu free inodes are flushed before we
379 	 * destroy cache.
380 	 */
381 	rcu_barrier();
382 	kmem_cache_destroy(qnx4_inode_cachep);
383 }
384 
385 static struct dentry *qnx4_mount(struct file_system_type *fs_type,
386 	int flags, const char *dev_name, void *data)
387 {
388 	return mount_bdev(fs_type, flags, dev_name, data, qnx4_fill_super);
389 }
390 
391 static struct file_system_type qnx4_fs_type = {
392 	.owner		= THIS_MODULE,
393 	.name		= "qnx4",
394 	.mount		= qnx4_mount,
395 	.kill_sb	= qnx4_kill_sb,
396 	.fs_flags	= FS_REQUIRES_DEV,
397 };
398 MODULE_ALIAS_FS("qnx4");
399 
400 static int __init init_qnx4_fs(void)
401 {
402 	int err;
403 
404 	err = init_inodecache();
405 	if (err)
406 		return err;
407 
408 	err = register_filesystem(&qnx4_fs_type);
409 	if (err) {
410 		destroy_inodecache();
411 		return err;
412 	}
413 
414 	printk(KERN_INFO "QNX4 filesystem 0.2.3 registered.\n");
415 	return 0;
416 }
417 
418 static void __exit exit_qnx4_fs(void)
419 {
420 	unregister_filesystem(&qnx4_fs_type);
421 	destroy_inodecache();
422 }
423 
424 module_init(init_qnx4_fs)
425 module_exit(exit_qnx4_fs)
426 MODULE_LICENSE("GPL");
427 
428