xref: /openbmc/linux/fs/qnx4/inode.c (revision e8e0929d)
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/smp_lock.h>
20 #include <linux/pagemap.h>
21 #include <linux/buffer_head.h>
22 #include <linux/writeback.h>
23 #include <linux/statfs.h>
24 #include "qnx4.h"
25 
26 #define QNX4_VERSION  4
27 #define QNX4_BMNAME   ".bitmap"
28 
29 static const struct super_operations qnx4_sops;
30 
31 static void qnx4_put_super(struct super_block *sb);
32 static struct inode *qnx4_alloc_inode(struct super_block *sb);
33 static void qnx4_destroy_inode(struct inode *inode);
34 static int qnx4_remount(struct super_block *sb, int *flags, char *data);
35 static int qnx4_statfs(struct dentry *, struct kstatfs *);
36 
37 static const struct super_operations qnx4_sops =
38 {
39 	.alloc_inode	= qnx4_alloc_inode,
40 	.destroy_inode	= qnx4_destroy_inode,
41 	.put_super	= qnx4_put_super,
42 	.statfs		= qnx4_statfs,
43 	.remount_fs	= qnx4_remount,
44 };
45 
46 static int qnx4_remount(struct super_block *sb, int *flags, char *data)
47 {
48 	struct qnx4_sb_info *qs;
49 
50 	qs = qnx4_sb(sb);
51 	qs->Version = QNX4_VERSION;
52 	*flags |= MS_RDONLY;
53 	return 0;
54 }
55 
56 static struct buffer_head *qnx4_getblk(struct inode *inode, int nr,
57 				       int create)
58 {
59 	struct buffer_head *result = NULL;
60 
61 	if ( nr >= 0 )
62 		nr = qnx4_block_map( inode, nr );
63 	if (nr) {
64 		result = sb_getblk(inode->i_sb, nr);
65 		return result;
66 	}
67 	if (!create) {
68 		return NULL;
69 	}
70 #if 0
71 	tmp = qnx4_new_block(inode->i_sb);
72 	if (!tmp) {
73 		return NULL;
74 	}
75 	result = sb_getblk(inode->i_sb, tmp);
76 	if (tst) {
77 		qnx4_free_block(inode->i_sb, tmp);
78 		brelse(result);
79 		goto repeat;
80 	}
81 	tst = tmp;
82 #endif
83 	inode->i_ctime = CURRENT_TIME_SEC;
84 	mark_inode_dirty(inode);
85 	return result;
86 }
87 
88 struct buffer_head *qnx4_bread(struct inode *inode, int block, int create)
89 {
90 	struct buffer_head *bh;
91 
92 	bh = qnx4_getblk(inode, block, create);
93 	if (!bh || buffer_uptodate(bh)) {
94 		return bh;
95 	}
96 	ll_rw_block(READ, 1, &bh);
97 	wait_on_buffer(bh);
98 	if (buffer_uptodate(bh)) {
99 		return bh;
100 	}
101 	brelse(bh);
102 
103 	return NULL;
104 }
105 
106 static int qnx4_get_block( struct inode *inode, sector_t iblock, struct buffer_head *bh, int create )
107 {
108 	unsigned long phys;
109 
110 	QNX4DEBUG(("qnx4: qnx4_get_block inode=[%ld] iblock=[%ld]\n",inode->i_ino,iblock));
111 
112 	phys = qnx4_block_map( inode, iblock );
113 	if ( phys ) {
114 		// logical block is before EOF
115 		map_bh(bh, inode->i_sb, phys);
116 	} else if ( create ) {
117 		// to be done.
118 	}
119 	return 0;
120 }
121 
122 unsigned long qnx4_block_map( struct inode *inode, long iblock )
123 {
124 	int ix;
125 	long offset, i_xblk;
126 	unsigned long block = 0;
127 	struct buffer_head *bh = NULL;
128 	struct qnx4_xblk *xblk = NULL;
129 	struct qnx4_inode_entry *qnx4_inode = qnx4_raw_inode(inode);
130 	u16 nxtnt = le16_to_cpu(qnx4_inode->di_num_xtnts);
131 
132 	if ( iblock < le32_to_cpu(qnx4_inode->di_first_xtnt.xtnt_size) ) {
133 		// iblock is in the first extent. This is easy.
134 		block = le32_to_cpu(qnx4_inode->di_first_xtnt.xtnt_blk) + iblock - 1;
135 	} else {
136 		// iblock is beyond first extent. We have to follow the extent chain.
137 		i_xblk = le32_to_cpu(qnx4_inode->di_xblk);
138 		offset = iblock - le32_to_cpu(qnx4_inode->di_first_xtnt.xtnt_size);
139 		ix = 0;
140 		while ( --nxtnt > 0 ) {
141 			if ( ix == 0 ) {
142 				// read next xtnt block.
143 				bh = sb_bread(inode->i_sb, i_xblk - 1);
144 				if ( !bh ) {
145 					QNX4DEBUG(("qnx4: I/O error reading xtnt block [%ld])\n", i_xblk - 1));
146 					return -EIO;
147 				}
148 				xblk = (struct qnx4_xblk*)bh->b_data;
149 				if ( memcmp( xblk->xblk_signature, "IamXblk", 7 ) ) {
150 					QNX4DEBUG(("qnx4: block at %ld is not a valid xtnt\n", qnx4_inode->i_xblk));
151 					return -EIO;
152 				}
153 			}
154 			if ( offset < le32_to_cpu(xblk->xblk_xtnts[ix].xtnt_size) ) {
155 				// got it!
156 				block = le32_to_cpu(xblk->xblk_xtnts[ix].xtnt_blk) + offset - 1;
157 				break;
158 			}
159 			offset -= le32_to_cpu(xblk->xblk_xtnts[ix].xtnt_size);
160 			if ( ++ix >= xblk->xblk_num_xtnts ) {
161 				i_xblk = le32_to_cpu(xblk->xblk_next_xblk);
162 				ix = 0;
163 				brelse( bh );
164 				bh = NULL;
165 			}
166 		}
167 		if ( bh )
168 			brelse( bh );
169 	}
170 
171 	QNX4DEBUG(("qnx4: mapping block %ld of inode %ld = %ld\n",iblock,inode->i_ino,block));
172 	return block;
173 }
174 
175 static int qnx4_statfs(struct dentry *dentry, struct kstatfs *buf)
176 {
177 	struct super_block *sb = dentry->d_sb;
178 	u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
179 
180 	lock_kernel();
181 
182 	buf->f_type    = sb->s_magic;
183 	buf->f_bsize   = sb->s_blocksize;
184 	buf->f_blocks  = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size) * 8;
185 	buf->f_bfree   = qnx4_count_free_blocks(sb);
186 	buf->f_bavail  = buf->f_bfree;
187 	buf->f_namelen = QNX4_NAME_MAX;
188 	buf->f_fsid.val[0] = (u32)id;
189 	buf->f_fsid.val[1] = (u32)(id >> 32);
190 
191 	unlock_kernel();
192 
193 	return 0;
194 }
195 
196 /*
197  * Check the root directory of the filesystem to make sure
198  * it really _is_ a qnx4 filesystem, and to check the size
199  * of the directory entry.
200  */
201 static const char *qnx4_checkroot(struct super_block *sb)
202 {
203 	struct buffer_head *bh;
204 	struct qnx4_inode_entry *rootdir;
205 	int rd, rl;
206 	int i, j;
207 	int found = 0;
208 
209 	if (*(qnx4_sb(sb)->sb->RootDir.di_fname) != '/') {
210 		return "no qnx4 filesystem (no root dir).";
211 	} else {
212 		QNX4DEBUG(("QNX4 filesystem found on dev %s.\n", sb->s_id));
213 		rd = le32_to_cpu(qnx4_sb(sb)->sb->RootDir.di_first_xtnt.xtnt_blk) - 1;
214 		rl = le32_to_cpu(qnx4_sb(sb)->sb->RootDir.di_first_xtnt.xtnt_size);
215 		for (j = 0; j < rl; j++) {
216 			bh = sb_bread(sb, rd + j);	/* root dir, first block */
217 			if (bh == NULL) {
218 				return "unable to read root entry.";
219 			}
220 			for (i = 0; i < QNX4_INODES_PER_BLOCK; i++) {
221 				rootdir = (struct qnx4_inode_entry *) (bh->b_data + i * QNX4_DIR_ENTRY_SIZE);
222 				if (rootdir->di_fname != NULL) {
223 					QNX4DEBUG(("Rootdir entry found : [%s]\n", rootdir->di_fname));
224 					if (!strncmp(rootdir->di_fname, QNX4_BMNAME, sizeof QNX4_BMNAME)) {
225 						found = 1;
226 						qnx4_sb(sb)->BitMap = kmalloc( sizeof( struct qnx4_inode_entry ), GFP_KERNEL );
227 						if (!qnx4_sb(sb)->BitMap) {
228 							brelse (bh);
229 							return "not enough memory for bitmap inode";
230 						}
231 						memcpy( qnx4_sb(sb)->BitMap, rootdir, sizeof( struct qnx4_inode_entry ) );	/* keep bitmap inode known */
232 						break;
233 					}
234 				}
235 			}
236 			brelse(bh);
237 			if (found != 0) {
238 				break;
239 			}
240 		}
241 		if (found == 0) {
242 			return "bitmap file not found.";
243 		}
244 	}
245 	return NULL;
246 }
247 
248 static int qnx4_fill_super(struct super_block *s, void *data, int silent)
249 {
250 	struct buffer_head *bh;
251 	struct inode *root;
252 	const char *errmsg;
253 	struct qnx4_sb_info *qs;
254 	int ret = -EINVAL;
255 
256 	qs = kzalloc(sizeof(struct qnx4_sb_info), GFP_KERNEL);
257 	if (!qs)
258 		return -ENOMEM;
259 	s->s_fs_info = qs;
260 
261 	sb_set_blocksize(s, QNX4_BLOCK_SIZE);
262 
263 	/* Check the superblock signature. Since the qnx4 code is
264 	   dangerous, we should leave as quickly as possible
265 	   if we don't belong here... */
266 	bh = sb_bread(s, 1);
267 	if (!bh) {
268 		printk("qnx4: unable to read the superblock\n");
269 		goto outnobh;
270 	}
271 	if ( le32_to_cpup((__le32*) bh->b_data) != QNX4_SUPER_MAGIC ) {
272 		if (!silent)
273 			printk("qnx4: wrong fsid in superblock.\n");
274 		goto out;
275 	}
276 	s->s_op = &qnx4_sops;
277 	s->s_magic = QNX4_SUPER_MAGIC;
278 	s->s_flags |= MS_RDONLY;	/* Yup, read-only yet */
279 	qnx4_sb(s)->sb_buf = bh;
280 	qnx4_sb(s)->sb = (struct qnx4_super_block *) bh->b_data;
281 
282 
283  	/* check before allocating dentries, inodes, .. */
284 	errmsg = qnx4_checkroot(s);
285 	if (errmsg != NULL) {
286  		if (!silent)
287  			printk("qnx4: %s\n", errmsg);
288 		goto out;
289 	}
290 
291  	/* does root not have inode number QNX4_ROOT_INO ?? */
292 	root = qnx4_iget(s, QNX4_ROOT_INO * QNX4_INODES_PER_BLOCK);
293 	if (IS_ERR(root)) {
294  		printk("qnx4: get inode failed\n");
295 		ret = PTR_ERR(root);
296  		goto out;
297  	}
298 
299 	ret = -ENOMEM;
300  	s->s_root = d_alloc_root(root);
301  	if (s->s_root == NULL)
302  		goto outi;
303 
304 	brelse(bh);
305 
306 	return 0;
307 
308       outi:
309 	iput(root);
310       out:
311 	brelse(bh);
312       outnobh:
313 	kfree(qs);
314 	s->s_fs_info = NULL;
315 	return ret;
316 }
317 
318 static void qnx4_put_super(struct super_block *sb)
319 {
320 	struct qnx4_sb_info *qs = qnx4_sb(sb);
321 	kfree( qs->BitMap );
322 	kfree( qs );
323 	sb->s_fs_info = NULL;
324 	return;
325 }
326 
327 static int qnx4_writepage(struct page *page, struct writeback_control *wbc)
328 {
329 	return block_write_full_page(page,qnx4_get_block, wbc);
330 }
331 
332 static int qnx4_readpage(struct file *file, struct page *page)
333 {
334 	return block_read_full_page(page,qnx4_get_block);
335 }
336 
337 static int qnx4_write_begin(struct file *file, struct address_space *mapping,
338 			loff_t pos, unsigned len, unsigned flags,
339 			struct page **pagep, void **fsdata)
340 {
341 	struct qnx4_inode_info *qnx4_inode = qnx4_i(mapping->host);
342 	*pagep = NULL;
343 	return cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
344 				qnx4_get_block,
345 				&qnx4_inode->mmu_private);
346 }
347 static sector_t qnx4_bmap(struct address_space *mapping, sector_t block)
348 {
349 	return generic_block_bmap(mapping,block,qnx4_get_block);
350 }
351 static const struct address_space_operations qnx4_aops = {
352 	.readpage	= qnx4_readpage,
353 	.writepage	= qnx4_writepage,
354 	.sync_page	= block_sync_page,
355 	.write_begin	= qnx4_write_begin,
356 	.write_end	= generic_write_end,
357 	.bmap		= qnx4_bmap
358 };
359 
360 struct inode *qnx4_iget(struct super_block *sb, unsigned long ino)
361 {
362 	struct buffer_head *bh;
363 	struct qnx4_inode_entry *raw_inode;
364 	int block;
365 	struct qnx4_inode_entry *qnx4_inode;
366 	struct inode *inode;
367 
368 	inode = iget_locked(sb, ino);
369 	if (!inode)
370 		return ERR_PTR(-ENOMEM);
371 	if (!(inode->i_state & I_NEW))
372 		return inode;
373 
374 	qnx4_inode = qnx4_raw_inode(inode);
375 	inode->i_mode = 0;
376 
377 	QNX4DEBUG(("Reading inode : [%d]\n", ino));
378 	if (!ino) {
379 		printk(KERN_ERR "qnx4: bad inode number on dev %s: %lu is "
380 				"out of range\n",
381 		       sb->s_id, ino);
382 		iget_failed(inode);
383 		return ERR_PTR(-EIO);
384 	}
385 	block = ino / QNX4_INODES_PER_BLOCK;
386 
387 	if (!(bh = sb_bread(sb, block))) {
388 		printk("qnx4: major problem: unable to read inode from dev "
389 		       "%s\n", sb->s_id);
390 		iget_failed(inode);
391 		return ERR_PTR(-EIO);
392 	}
393 	raw_inode = ((struct qnx4_inode_entry *) bh->b_data) +
394 	    (ino % QNX4_INODES_PER_BLOCK);
395 
396 	inode->i_mode    = le16_to_cpu(raw_inode->di_mode);
397 	inode->i_uid     = (uid_t)le16_to_cpu(raw_inode->di_uid);
398 	inode->i_gid     = (gid_t)le16_to_cpu(raw_inode->di_gid);
399 	inode->i_nlink   = le16_to_cpu(raw_inode->di_nlink);
400 	inode->i_size    = le32_to_cpu(raw_inode->di_size);
401 	inode->i_mtime.tv_sec   = le32_to_cpu(raw_inode->di_mtime);
402 	inode->i_mtime.tv_nsec = 0;
403 	inode->i_atime.tv_sec   = le32_to_cpu(raw_inode->di_atime);
404 	inode->i_atime.tv_nsec = 0;
405 	inode->i_ctime.tv_sec   = le32_to_cpu(raw_inode->di_ctime);
406 	inode->i_ctime.tv_nsec = 0;
407 	inode->i_blocks  = le32_to_cpu(raw_inode->di_first_xtnt.xtnt_size);
408 
409 	memcpy(qnx4_inode, raw_inode, QNX4_DIR_ENTRY_SIZE);
410 	if (S_ISREG(inode->i_mode)) {
411 		inode->i_fop = &generic_ro_fops;
412 		inode->i_mapping->a_ops = &qnx4_aops;
413 		qnx4_i(inode)->mmu_private = inode->i_size;
414 	} else if (S_ISDIR(inode->i_mode)) {
415 		inode->i_op = &qnx4_dir_inode_operations;
416 		inode->i_fop = &qnx4_dir_operations;
417 	} else if (S_ISLNK(inode->i_mode)) {
418 		inode->i_op = &page_symlink_inode_operations;
419 		inode->i_mapping->a_ops = &qnx4_aops;
420 		qnx4_i(inode)->mmu_private = inode->i_size;
421 	} else {
422 		printk(KERN_ERR "qnx4: bad inode %lu on dev %s\n",
423 			ino, sb->s_id);
424 		iget_failed(inode);
425 		brelse(bh);
426 		return ERR_PTR(-EIO);
427 	}
428 	brelse(bh);
429 	unlock_new_inode(inode);
430 	return inode;
431 }
432 
433 static struct kmem_cache *qnx4_inode_cachep;
434 
435 static struct inode *qnx4_alloc_inode(struct super_block *sb)
436 {
437 	struct qnx4_inode_info *ei;
438 	ei = kmem_cache_alloc(qnx4_inode_cachep, GFP_KERNEL);
439 	if (!ei)
440 		return NULL;
441 	return &ei->vfs_inode;
442 }
443 
444 static void qnx4_destroy_inode(struct inode *inode)
445 {
446 	kmem_cache_free(qnx4_inode_cachep, qnx4_i(inode));
447 }
448 
449 static void init_once(void *foo)
450 {
451 	struct qnx4_inode_info *ei = (struct qnx4_inode_info *) foo;
452 
453 	inode_init_once(&ei->vfs_inode);
454 }
455 
456 static int init_inodecache(void)
457 {
458 	qnx4_inode_cachep = kmem_cache_create("qnx4_inode_cache",
459 					     sizeof(struct qnx4_inode_info),
460 					     0, (SLAB_RECLAIM_ACCOUNT|
461 						SLAB_MEM_SPREAD),
462 					     init_once);
463 	if (qnx4_inode_cachep == NULL)
464 		return -ENOMEM;
465 	return 0;
466 }
467 
468 static void destroy_inodecache(void)
469 {
470 	kmem_cache_destroy(qnx4_inode_cachep);
471 }
472 
473 static int qnx4_get_sb(struct file_system_type *fs_type,
474 	int flags, const char *dev_name, void *data, struct vfsmount *mnt)
475 {
476 	return get_sb_bdev(fs_type, flags, dev_name, data, qnx4_fill_super,
477 			   mnt);
478 }
479 
480 static struct file_system_type qnx4_fs_type = {
481 	.owner		= THIS_MODULE,
482 	.name		= "qnx4",
483 	.get_sb		= qnx4_get_sb,
484 	.kill_sb	= kill_block_super,
485 	.fs_flags	= FS_REQUIRES_DEV,
486 };
487 
488 static int __init init_qnx4_fs(void)
489 {
490 	int err;
491 
492 	err = init_inodecache();
493 	if (err)
494 		return err;
495 
496 	err = register_filesystem(&qnx4_fs_type);
497 	if (err) {
498 		destroy_inodecache();
499 		return err;
500 	}
501 
502 	printk("QNX4 filesystem 0.2.3 registered.\n");
503 	return 0;
504 }
505 
506 static void __exit exit_qnx4_fs(void)
507 {
508 	unregister_filesystem(&qnx4_fs_type);
509 	destroy_inodecache();
510 }
511 
512 module_init(init_qnx4_fs)
513 module_exit(exit_qnx4_fs)
514 MODULE_LICENSE("GPL");
515 
516