xref: /openbmc/linux/fs/qnx4/inode.c (revision b595076a)
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 void qnx4_put_super(struct super_block *sb);
31 static struct inode *qnx4_alloc_inode(struct super_block *sb);
32 static void qnx4_destroy_inode(struct inode *inode);
33 static int qnx4_remount(struct super_block *sb, int *flags, char *data);
34 static int qnx4_statfs(struct dentry *, struct kstatfs *);
35 
36 static const struct super_operations qnx4_sops =
37 {
38 	.alloc_inode	= qnx4_alloc_inode,
39 	.destroy_inode	= qnx4_destroy_inode,
40 	.put_super	= qnx4_put_super,
41 	.statfs		= qnx4_statfs,
42 	.remount_fs	= qnx4_remount,
43 };
44 
45 static int qnx4_remount(struct super_block *sb, int *flags, char *data)
46 {
47 	struct qnx4_sb_info *qs;
48 
49 	qs = qnx4_sb(sb);
50 	qs->Version = QNX4_VERSION;
51 	*flags |= MS_RDONLY;
52 	return 0;
53 }
54 
55 static struct buffer_head *qnx4_getblk(struct inode *inode, int nr,
56 				       int create)
57 {
58 	struct buffer_head *result = NULL;
59 
60 	if ( nr >= 0 )
61 		nr = qnx4_block_map( inode, nr );
62 	if (nr) {
63 		result = sb_getblk(inode->i_sb, nr);
64 		return result;
65 	}
66 	return NULL;
67 }
68 
69 struct buffer_head *qnx4_bread(struct inode *inode, int block, int create)
70 {
71 	struct buffer_head *bh;
72 
73 	bh = qnx4_getblk(inode, block, create);
74 	if (!bh || buffer_uptodate(bh)) {
75 		return bh;
76 	}
77 	ll_rw_block(READ, 1, &bh);
78 	wait_on_buffer(bh);
79 	if (buffer_uptodate(bh)) {
80 		return bh;
81 	}
82 	brelse(bh);
83 
84 	return NULL;
85 }
86 
87 static int qnx4_get_block( struct inode *inode, sector_t iblock, struct buffer_head *bh, int create )
88 {
89 	unsigned long phys;
90 
91 	QNX4DEBUG((KERN_INFO "qnx4: qnx4_get_block inode=[%ld] iblock=[%ld]\n",inode->i_ino,iblock));
92 
93 	phys = qnx4_block_map( inode, iblock );
94 	if ( phys ) {
95 		// logical block is before EOF
96 		map_bh(bh, inode->i_sb, phys);
97 	}
98 	return 0;
99 }
100 
101 unsigned long qnx4_block_map( struct inode *inode, long iblock )
102 {
103 	int ix;
104 	long offset, i_xblk;
105 	unsigned long block = 0;
106 	struct buffer_head *bh = NULL;
107 	struct qnx4_xblk *xblk = NULL;
108 	struct qnx4_inode_entry *qnx4_inode = qnx4_raw_inode(inode);
109 	u16 nxtnt = le16_to_cpu(qnx4_inode->di_num_xtnts);
110 
111 	if ( iblock < le32_to_cpu(qnx4_inode->di_first_xtnt.xtnt_size) ) {
112 		// iblock is in the first extent. This is easy.
113 		block = le32_to_cpu(qnx4_inode->di_first_xtnt.xtnt_blk) + iblock - 1;
114 	} else {
115 		// iblock is beyond first extent. We have to follow the extent chain.
116 		i_xblk = le32_to_cpu(qnx4_inode->di_xblk);
117 		offset = iblock - le32_to_cpu(qnx4_inode->di_first_xtnt.xtnt_size);
118 		ix = 0;
119 		while ( --nxtnt > 0 ) {
120 			if ( ix == 0 ) {
121 				// read next xtnt block.
122 				bh = sb_bread(inode->i_sb, i_xblk - 1);
123 				if ( !bh ) {
124 					QNX4DEBUG((KERN_ERR "qnx4: I/O error reading xtnt block [%ld])\n", i_xblk - 1));
125 					return -EIO;
126 				}
127 				xblk = (struct qnx4_xblk*)bh->b_data;
128 				if ( memcmp( xblk->xblk_signature, "IamXblk", 7 ) ) {
129 					QNX4DEBUG((KERN_ERR "qnx4: block at %ld is not a valid xtnt\n", qnx4_inode->i_xblk));
130 					return -EIO;
131 				}
132 			}
133 			if ( offset < le32_to_cpu(xblk->xblk_xtnts[ix].xtnt_size) ) {
134 				// got it!
135 				block = le32_to_cpu(xblk->xblk_xtnts[ix].xtnt_blk) + offset - 1;
136 				break;
137 			}
138 			offset -= le32_to_cpu(xblk->xblk_xtnts[ix].xtnt_size);
139 			if ( ++ix >= xblk->xblk_num_xtnts ) {
140 				i_xblk = le32_to_cpu(xblk->xblk_next_xblk);
141 				ix = 0;
142 				brelse( bh );
143 				bh = NULL;
144 			}
145 		}
146 		if ( bh )
147 			brelse( bh );
148 	}
149 
150 	QNX4DEBUG((KERN_INFO "qnx4: mapping block %ld of inode %ld = %ld\n",iblock,inode->i_ino,block));
151 	return block;
152 }
153 
154 static int qnx4_statfs(struct dentry *dentry, struct kstatfs *buf)
155 {
156 	struct super_block *sb = dentry->d_sb;
157 	u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
158 
159 	buf->f_type    = sb->s_magic;
160 	buf->f_bsize   = sb->s_blocksize;
161 	buf->f_blocks  = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size) * 8;
162 	buf->f_bfree   = qnx4_count_free_blocks(sb);
163 	buf->f_bavail  = buf->f_bfree;
164 	buf->f_namelen = QNX4_NAME_MAX;
165 	buf->f_fsid.val[0] = (u32)id;
166 	buf->f_fsid.val[1] = (u32)(id >> 32);
167 
168 	return 0;
169 }
170 
171 /*
172  * Check the root directory of the filesystem to make sure
173  * it really _is_ a qnx4 filesystem, and to check the size
174  * of the directory entry.
175  */
176 static const char *qnx4_checkroot(struct super_block *sb)
177 {
178 	struct buffer_head *bh;
179 	struct qnx4_inode_entry *rootdir;
180 	int rd, rl;
181 	int i, j;
182 	int found = 0;
183 
184 	if (*(qnx4_sb(sb)->sb->RootDir.di_fname) != '/') {
185 		return "no qnx4 filesystem (no root dir).";
186 	} else {
187 		QNX4DEBUG((KERN_NOTICE "QNX4 filesystem found on dev %s.\n", sb->s_id));
188 		rd = le32_to_cpu(qnx4_sb(sb)->sb->RootDir.di_first_xtnt.xtnt_blk) - 1;
189 		rl = le32_to_cpu(qnx4_sb(sb)->sb->RootDir.di_first_xtnt.xtnt_size);
190 		for (j = 0; j < rl; j++) {
191 			bh = sb_bread(sb, rd + j);	/* root dir, first block */
192 			if (bh == NULL) {
193 				return "unable to read root entry.";
194 			}
195 			for (i = 0; i < QNX4_INODES_PER_BLOCK; i++) {
196 				rootdir = (struct qnx4_inode_entry *) (bh->b_data + i * QNX4_DIR_ENTRY_SIZE);
197 				if (rootdir->di_fname != NULL) {
198 					QNX4DEBUG((KERN_INFO "rootdir entry found : [%s]\n", rootdir->di_fname));
199 					if (!strcmp(rootdir->di_fname,
200 						    QNX4_BMNAME)) {
201 						found = 1;
202 						qnx4_sb(sb)->BitMap = kmalloc( sizeof( struct qnx4_inode_entry ), GFP_KERNEL );
203 						if (!qnx4_sb(sb)->BitMap) {
204 							brelse (bh);
205 							return "not enough memory for bitmap inode";
206 						}
207 						memcpy( qnx4_sb(sb)->BitMap, rootdir, sizeof( struct qnx4_inode_entry ) );	/* keep bitmap inode known */
208 						break;
209 					}
210 				}
211 			}
212 			brelse(bh);
213 			if (found != 0) {
214 				break;
215 			}
216 		}
217 		if (found == 0) {
218 			return "bitmap file not found.";
219 		}
220 	}
221 	return NULL;
222 }
223 
224 static int qnx4_fill_super(struct super_block *s, void *data, int silent)
225 {
226 	struct buffer_head *bh;
227 	struct inode *root;
228 	const char *errmsg;
229 	struct qnx4_sb_info *qs;
230 	int ret = -EINVAL;
231 
232 	qs = kzalloc(sizeof(struct qnx4_sb_info), GFP_KERNEL);
233 	if (!qs)
234 		return -ENOMEM;
235 	s->s_fs_info = qs;
236 
237 	sb_set_blocksize(s, QNX4_BLOCK_SIZE);
238 
239 	/* Check the superblock signature. Since the qnx4 code is
240 	   dangerous, we should leave as quickly as possible
241 	   if we don't belong here... */
242 	bh = sb_bread(s, 1);
243 	if (!bh) {
244 		printk(KERN_ERR "qnx4: unable to read the superblock\n");
245 		goto outnobh;
246 	}
247 	if ( le32_to_cpup((__le32*) bh->b_data) != QNX4_SUPER_MAGIC ) {
248 		if (!silent)
249 			printk(KERN_ERR "qnx4: wrong fsid in superblock.\n");
250 		goto out;
251 	}
252 	s->s_op = &qnx4_sops;
253 	s->s_magic = QNX4_SUPER_MAGIC;
254 	s->s_flags |= MS_RDONLY;	/* Yup, read-only yet */
255 	qnx4_sb(s)->sb_buf = bh;
256 	qnx4_sb(s)->sb = (struct qnx4_super_block *) bh->b_data;
257 
258 
259  	/* check before allocating dentries, inodes, .. */
260 	errmsg = qnx4_checkroot(s);
261 	if (errmsg != NULL) {
262  		if (!silent)
263 			printk(KERN_ERR "qnx4: %s\n", errmsg);
264 		goto out;
265 	}
266 
267  	/* does root not have inode number QNX4_ROOT_INO ?? */
268 	root = qnx4_iget(s, QNX4_ROOT_INO * QNX4_INODES_PER_BLOCK);
269 	if (IS_ERR(root)) {
270 		printk(KERN_ERR "qnx4: get inode failed\n");
271 		ret = PTR_ERR(root);
272  		goto out;
273  	}
274 
275 	ret = -ENOMEM;
276  	s->s_root = d_alloc_root(root);
277  	if (s->s_root == NULL)
278  		goto outi;
279 
280 	brelse(bh);
281 	return 0;
282 
283       outi:
284 	iput(root);
285       out:
286 	brelse(bh);
287       outnobh:
288 	kfree(qs);
289 	s->s_fs_info = NULL;
290 	return ret;
291 }
292 
293 static void qnx4_put_super(struct super_block *sb)
294 {
295 	struct qnx4_sb_info *qs = qnx4_sb(sb);
296 	kfree( qs->BitMap );
297 	kfree( qs );
298 	sb->s_fs_info = NULL;
299 	return;
300 }
301 
302 static int qnx4_writepage(struct page *page, struct writeback_control *wbc)
303 {
304 	return block_write_full_page(page,qnx4_get_block, wbc);
305 }
306 
307 static int qnx4_readpage(struct file *file, struct page *page)
308 {
309 	return block_read_full_page(page,qnx4_get_block);
310 }
311 
312 static int qnx4_write_begin(struct file *file, struct address_space *mapping,
313 			loff_t pos, unsigned len, unsigned flags,
314 			struct page **pagep, void **fsdata)
315 {
316 	struct qnx4_inode_info *qnx4_inode = qnx4_i(mapping->host);
317 	int ret;
318 
319 	*pagep = NULL;
320 	ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
321 				qnx4_get_block,
322 				&qnx4_inode->mmu_private);
323 	if (unlikely(ret)) {
324 		loff_t isize = mapping->host->i_size;
325 		if (pos + len > isize)
326 			vmtruncate(mapping->host, isize);
327 	}
328 
329 	return ret;
330 }
331 static sector_t qnx4_bmap(struct address_space *mapping, sector_t block)
332 {
333 	return generic_block_bmap(mapping,block,qnx4_get_block);
334 }
335 static const struct address_space_operations qnx4_aops = {
336 	.readpage	= qnx4_readpage,
337 	.writepage	= qnx4_writepage,
338 	.sync_page	= block_sync_page,
339 	.write_begin	= qnx4_write_begin,
340 	.write_end	= generic_write_end,
341 	.bmap		= qnx4_bmap
342 };
343 
344 struct inode *qnx4_iget(struct super_block *sb, unsigned long ino)
345 {
346 	struct buffer_head *bh;
347 	struct qnx4_inode_entry *raw_inode;
348 	int block;
349 	struct qnx4_inode_entry *qnx4_inode;
350 	struct inode *inode;
351 
352 	inode = iget_locked(sb, ino);
353 	if (!inode)
354 		return ERR_PTR(-ENOMEM);
355 	if (!(inode->i_state & I_NEW))
356 		return inode;
357 
358 	qnx4_inode = qnx4_raw_inode(inode);
359 	inode->i_mode = 0;
360 
361 	QNX4DEBUG((KERN_INFO "reading inode : [%d]\n", ino));
362 	if (!ino) {
363 		printk(KERN_ERR "qnx4: bad inode number on dev %s: %lu is "
364 				"out of range\n",
365 		       sb->s_id, ino);
366 		iget_failed(inode);
367 		return ERR_PTR(-EIO);
368 	}
369 	block = ino / QNX4_INODES_PER_BLOCK;
370 
371 	if (!(bh = sb_bread(sb, block))) {
372 		printk(KERN_ERR "qnx4: major problem: unable to read inode from dev "
373 		       "%s\n", sb->s_id);
374 		iget_failed(inode);
375 		return ERR_PTR(-EIO);
376 	}
377 	raw_inode = ((struct qnx4_inode_entry *) bh->b_data) +
378 	    (ino % QNX4_INODES_PER_BLOCK);
379 
380 	inode->i_mode    = le16_to_cpu(raw_inode->di_mode);
381 	inode->i_uid     = (uid_t)le16_to_cpu(raw_inode->di_uid);
382 	inode->i_gid     = (gid_t)le16_to_cpu(raw_inode->di_gid);
383 	inode->i_nlink   = le16_to_cpu(raw_inode->di_nlink);
384 	inode->i_size    = le32_to_cpu(raw_inode->di_size);
385 	inode->i_mtime.tv_sec   = le32_to_cpu(raw_inode->di_mtime);
386 	inode->i_mtime.tv_nsec = 0;
387 	inode->i_atime.tv_sec   = le32_to_cpu(raw_inode->di_atime);
388 	inode->i_atime.tv_nsec = 0;
389 	inode->i_ctime.tv_sec   = le32_to_cpu(raw_inode->di_ctime);
390 	inode->i_ctime.tv_nsec = 0;
391 	inode->i_blocks  = le32_to_cpu(raw_inode->di_first_xtnt.xtnt_size);
392 
393 	memcpy(qnx4_inode, raw_inode, QNX4_DIR_ENTRY_SIZE);
394 	if (S_ISREG(inode->i_mode)) {
395 		inode->i_fop = &generic_ro_fops;
396 		inode->i_mapping->a_ops = &qnx4_aops;
397 		qnx4_i(inode)->mmu_private = inode->i_size;
398 	} else if (S_ISDIR(inode->i_mode)) {
399 		inode->i_op = &qnx4_dir_inode_operations;
400 		inode->i_fop = &qnx4_dir_operations;
401 	} else if (S_ISLNK(inode->i_mode)) {
402 		inode->i_op = &page_symlink_inode_operations;
403 		inode->i_mapping->a_ops = &qnx4_aops;
404 		qnx4_i(inode)->mmu_private = inode->i_size;
405 	} else {
406 		printk(KERN_ERR "qnx4: bad inode %lu on dev %s\n",
407 			ino, sb->s_id);
408 		iget_failed(inode);
409 		brelse(bh);
410 		return ERR_PTR(-EIO);
411 	}
412 	brelse(bh);
413 	unlock_new_inode(inode);
414 	return inode;
415 }
416 
417 static struct kmem_cache *qnx4_inode_cachep;
418 
419 static struct inode *qnx4_alloc_inode(struct super_block *sb)
420 {
421 	struct qnx4_inode_info *ei;
422 	ei = kmem_cache_alloc(qnx4_inode_cachep, GFP_KERNEL);
423 	if (!ei)
424 		return NULL;
425 	return &ei->vfs_inode;
426 }
427 
428 static void qnx4_destroy_inode(struct inode *inode)
429 {
430 	kmem_cache_free(qnx4_inode_cachep, qnx4_i(inode));
431 }
432 
433 static void init_once(void *foo)
434 {
435 	struct qnx4_inode_info *ei = (struct qnx4_inode_info *) foo;
436 
437 	inode_init_once(&ei->vfs_inode);
438 }
439 
440 static int init_inodecache(void)
441 {
442 	qnx4_inode_cachep = kmem_cache_create("qnx4_inode_cache",
443 					     sizeof(struct qnx4_inode_info),
444 					     0, (SLAB_RECLAIM_ACCOUNT|
445 						SLAB_MEM_SPREAD),
446 					     init_once);
447 	if (qnx4_inode_cachep == NULL)
448 		return -ENOMEM;
449 	return 0;
450 }
451 
452 static void destroy_inodecache(void)
453 {
454 	kmem_cache_destroy(qnx4_inode_cachep);
455 }
456 
457 static struct dentry *qnx4_mount(struct file_system_type *fs_type,
458 	int flags, const char *dev_name, void *data)
459 {
460 	return mount_bdev(fs_type, flags, dev_name, data, qnx4_fill_super);
461 }
462 
463 static struct file_system_type qnx4_fs_type = {
464 	.owner		= THIS_MODULE,
465 	.name		= "qnx4",
466 	.mount		= qnx4_mount,
467 	.kill_sb	= kill_block_super,
468 	.fs_flags	= FS_REQUIRES_DEV,
469 };
470 
471 static int __init init_qnx4_fs(void)
472 {
473 	int err;
474 
475 	err = init_inodecache();
476 	if (err)
477 		return err;
478 
479 	err = register_filesystem(&qnx4_fs_type);
480 	if (err) {
481 		destroy_inodecache();
482 		return err;
483 	}
484 
485 	printk(KERN_INFO "QNX4 filesystem 0.2.3 registered.\n");
486 	return 0;
487 }
488 
489 static void __exit exit_qnx4_fs(void)
490 {
491 	unregister_filesystem(&qnx4_fs_type);
492 	destroy_inodecache();
493 }
494 
495 module_init(init_qnx4_fs)
496 module_exit(exit_qnx4_fs)
497 MODULE_LICENSE("GPL");
498 
499