xref: /openbmc/linux/fs/qnx4/inode.c (revision bbe21298)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * QNX4 file system, Linux implementation.
4  *
5  * Version : 0.2.1
6  *
7  * Using parts of the xiafs filesystem.
8  *
9  * History :
10  *
11  * 01-06-1998 by Richard Frowijn : first release.
12  * 20-06-1998 by Frank Denis : Linux 2.1.99+ support, boot signature, misc.
13  * 30-06-1998 by Frank Denis : first step to write inodes.
14  */
15 
16 #include <linux/module.h>
17 #include <linux/init.h>
18 #include <linux/slab.h>
19 #include <linux/highuid.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 struct inode *qnx4_alloc_inode(struct super_block *sb);
32 static void qnx4_free_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 	.free_inode	= qnx4_free_inode,
40 	.statfs		= qnx4_statfs,
41 	.remount_fs	= qnx4_remount,
42 };
43 
qnx4_remount(struct super_block * sb,int * flags,char * data)44 static int qnx4_remount(struct super_block *sb, int *flags, char *data)
45 {
46 	struct qnx4_sb_info *qs;
47 
48 	sync_filesystem(sb);
49 	qs = qnx4_sb(sb);
50 	qs->Version = QNX4_VERSION;
51 	*flags |= SB_RDONLY;
52 	return 0;
53 }
54 
qnx4_get_block(struct inode * inode,sector_t iblock,struct buffer_head * bh,int create)55 static int qnx4_get_block( struct inode *inode, sector_t iblock, struct buffer_head *bh, int create )
56 {
57 	unsigned long phys;
58 
59 	QNX4DEBUG((KERN_INFO "qnx4: qnx4_get_block inode=[%ld] iblock=[%ld]\n",inode->i_ino,iblock));
60 
61 	phys = qnx4_block_map( inode, iblock );
62 	if ( phys ) {
63 		// logical block is before EOF
64 		map_bh(bh, inode->i_sb, phys);
65 	}
66 	return 0;
67 }
68 
try_extent(qnx4_xtnt_t * extent,u32 * offset)69 static inline u32 try_extent(qnx4_xtnt_t *extent, u32 *offset)
70 {
71 	u32 size = le32_to_cpu(extent->xtnt_size);
72 	if (*offset < size)
73 		return le32_to_cpu(extent->xtnt_blk) + *offset - 1;
74 	*offset -= size;
75 	return 0;
76 }
77 
qnx4_block_map(struct inode * inode,long iblock)78 unsigned long qnx4_block_map( struct inode *inode, long iblock )
79 {
80 	int ix;
81 	long i_xblk;
82 	struct buffer_head *bh = NULL;
83 	struct qnx4_xblk *xblk = NULL;
84 	struct qnx4_inode_entry *qnx4_inode = qnx4_raw_inode(inode);
85 	u16 nxtnt = le16_to_cpu(qnx4_inode->di_num_xtnts);
86 	u32 offset = iblock;
87 	u32 block = try_extent(&qnx4_inode->di_first_xtnt, &offset);
88 
89 	if (block) {
90 		// iblock is in the first extent. This is easy.
91 	} else {
92 		// iblock is beyond first extent. We have to follow the extent chain.
93 		i_xblk = le32_to_cpu(qnx4_inode->di_xblk);
94 		ix = 0;
95 		while ( --nxtnt > 0 ) {
96 			if ( ix == 0 ) {
97 				// read next xtnt block.
98 				bh = sb_bread(inode->i_sb, i_xblk - 1);
99 				if ( !bh ) {
100 					QNX4DEBUG((KERN_ERR "qnx4: I/O error reading xtnt block [%ld])\n", i_xblk - 1));
101 					return -EIO;
102 				}
103 				xblk = (struct qnx4_xblk*)bh->b_data;
104 				if ( memcmp( xblk->xblk_signature, "IamXblk", 7 ) ) {
105 					QNX4DEBUG((KERN_ERR "qnx4: block at %ld is not a valid xtnt\n", qnx4_inode->i_xblk));
106 					return -EIO;
107 				}
108 			}
109 			block = try_extent(&xblk->xblk_xtnts[ix], &offset);
110 			if (block) {
111 				// got it!
112 				break;
113 			}
114 			if ( ++ix >= xblk->xblk_num_xtnts ) {
115 				i_xblk = le32_to_cpu(xblk->xblk_next_xblk);
116 				ix = 0;
117 				brelse( bh );
118 				bh = NULL;
119 			}
120 		}
121 		if ( bh )
122 			brelse( bh );
123 	}
124 
125 	QNX4DEBUG((KERN_INFO "qnx4: mapping block %ld of inode %ld = %ld\n",iblock,inode->i_ino,block));
126 	return block;
127 }
128 
qnx4_statfs(struct dentry * dentry,struct kstatfs * buf)129 static int qnx4_statfs(struct dentry *dentry, struct kstatfs *buf)
130 {
131 	struct super_block *sb = dentry->d_sb;
132 	u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
133 
134 	buf->f_type    = sb->s_magic;
135 	buf->f_bsize   = sb->s_blocksize;
136 	buf->f_blocks  = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size) * 8;
137 	buf->f_bfree   = qnx4_count_free_blocks(sb);
138 	buf->f_bavail  = buf->f_bfree;
139 	buf->f_namelen = QNX4_NAME_MAX;
140 	buf->f_fsid    = u64_to_fsid(id);
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  */
qnx4_checkroot(struct super_block * sb,struct qnx4_super_block * s)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 
qnx4_fill_super(struct super_block * s,void * data,int silent)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 |= SB_RDONLY;	/* Yup, read-only yet */
203 	s->s_time_min = 0;
204 	s->s_time_max = U32_MAX;
205 
206 	/* Check the superblock signature. Since the qnx4 code is
207 	   dangerous, we should leave as quickly as possible
208 	   if we don't belong here... */
209 	bh = sb_bread(s, 1);
210 	if (!bh) {
211 		printk(KERN_ERR "qnx4: unable to read the superblock\n");
212 		return -EINVAL;
213 	}
214 
215  	/* check before allocating dentries, inodes, .. */
216 	errmsg = qnx4_checkroot(s, (struct qnx4_super_block *) bh->b_data);
217 	brelse(bh);
218 	if (errmsg != NULL) {
219  		if (!silent)
220 			printk(KERN_ERR "qnx4: %s\n", errmsg);
221 		return -EINVAL;
222 	}
223 
224  	/* does root not have inode number QNX4_ROOT_INO ?? */
225 	root = qnx4_iget(s, QNX4_ROOT_INO * QNX4_INODES_PER_BLOCK);
226 	if (IS_ERR(root)) {
227 		printk(KERN_ERR "qnx4: get inode failed\n");
228 		return PTR_ERR(root);
229  	}
230 
231  	s->s_root = d_make_root(root);
232  	if (s->s_root == NULL)
233  		return -ENOMEM;
234 
235 	return 0;
236 }
237 
qnx4_kill_sb(struct super_block * sb)238 static void qnx4_kill_sb(struct super_block *sb)
239 {
240 	struct qnx4_sb_info *qs = qnx4_sb(sb);
241 	kill_block_super(sb);
242 	if (qs) {
243 		kfree(qs->BitMap);
244 		kfree(qs);
245 	}
246 }
247 
qnx4_read_folio(struct file * file,struct folio * folio)248 static int qnx4_read_folio(struct file *file, struct folio *folio)
249 {
250 	return block_read_full_folio(folio, qnx4_get_block);
251 }
252 
qnx4_bmap(struct address_space * mapping,sector_t block)253 static sector_t qnx4_bmap(struct address_space *mapping, sector_t block)
254 {
255 	return generic_block_bmap(mapping,block,qnx4_get_block);
256 }
257 
258 static const struct address_space_operations qnx4_aops = {
259 	.read_folio	= qnx4_read_folio,
260 	.bmap		= qnx4_bmap
261 };
262 
qnx4_iget(struct super_block * sb,unsigned long ino)263 struct inode *qnx4_iget(struct super_block *sb, unsigned long ino)
264 {
265 	struct buffer_head *bh;
266 	struct qnx4_inode_entry *raw_inode;
267 	int block;
268 	struct qnx4_inode_entry *qnx4_inode;
269 	struct inode *inode;
270 
271 	inode = iget_locked(sb, ino);
272 	if (!inode)
273 		return ERR_PTR(-ENOMEM);
274 	if (!(inode->i_state & I_NEW))
275 		return inode;
276 
277 	qnx4_inode = qnx4_raw_inode(inode);
278 	inode->i_mode = 0;
279 
280 	QNX4DEBUG((KERN_INFO "reading inode : [%d]\n", ino));
281 	if (!ino) {
282 		printk(KERN_ERR "qnx4: bad inode number on dev %s: %lu is "
283 				"out of range\n",
284 		       sb->s_id, ino);
285 		iget_failed(inode);
286 		return ERR_PTR(-EIO);
287 	}
288 	block = ino / QNX4_INODES_PER_BLOCK;
289 
290 	if (!(bh = sb_bread(sb, block))) {
291 		printk(KERN_ERR "qnx4: major problem: unable to read inode from dev "
292 		       "%s\n", sb->s_id);
293 		iget_failed(inode);
294 		return ERR_PTR(-EIO);
295 	}
296 	raw_inode = ((struct qnx4_inode_entry *) bh->b_data) +
297 	    (ino % QNX4_INODES_PER_BLOCK);
298 
299 	inode->i_mode    = le16_to_cpu(raw_inode->di_mode);
300 	i_uid_write(inode, (uid_t)le16_to_cpu(raw_inode->di_uid));
301 	i_gid_write(inode, (gid_t)le16_to_cpu(raw_inode->di_gid));
302 	set_nlink(inode, le16_to_cpu(raw_inode->di_nlink));
303 	inode->i_size    = le32_to_cpu(raw_inode->di_size);
304 	inode->i_mtime.tv_sec   = le32_to_cpu(raw_inode->di_mtime);
305 	inode->i_mtime.tv_nsec = 0;
306 	inode->i_atime.tv_sec   = le32_to_cpu(raw_inode->di_atime);
307 	inode->i_atime.tv_nsec = 0;
308 	inode_set_ctime(inode, le32_to_cpu(raw_inode->di_ctime), 0);
309 	inode->i_blocks  = le32_to_cpu(raw_inode->di_first_xtnt.xtnt_size);
310 
311 	memcpy(qnx4_inode, raw_inode, QNX4_DIR_ENTRY_SIZE);
312 	if (S_ISREG(inode->i_mode)) {
313 		inode->i_fop = &generic_ro_fops;
314 		inode->i_mapping->a_ops = &qnx4_aops;
315 		qnx4_i(inode)->mmu_private = inode->i_size;
316 	} else if (S_ISDIR(inode->i_mode)) {
317 		inode->i_op = &qnx4_dir_inode_operations;
318 		inode->i_fop = &qnx4_dir_operations;
319 	} else if (S_ISLNK(inode->i_mode)) {
320 		inode->i_op = &page_symlink_inode_operations;
321 		inode_nohighmem(inode);
322 		inode->i_mapping->a_ops = &qnx4_aops;
323 		qnx4_i(inode)->mmu_private = inode->i_size;
324 	} else {
325 		printk(KERN_ERR "qnx4: bad inode %lu on dev %s\n",
326 			ino, sb->s_id);
327 		iget_failed(inode);
328 		brelse(bh);
329 		return ERR_PTR(-EIO);
330 	}
331 	brelse(bh);
332 	unlock_new_inode(inode);
333 	return inode;
334 }
335 
336 static struct kmem_cache *qnx4_inode_cachep;
337 
qnx4_alloc_inode(struct super_block * sb)338 static struct inode *qnx4_alloc_inode(struct super_block *sb)
339 {
340 	struct qnx4_inode_info *ei;
341 	ei = alloc_inode_sb(sb, qnx4_inode_cachep, GFP_KERNEL);
342 	if (!ei)
343 		return NULL;
344 	return &ei->vfs_inode;
345 }
346 
qnx4_free_inode(struct inode * inode)347 static void qnx4_free_inode(struct inode *inode)
348 {
349 	kmem_cache_free(qnx4_inode_cachep, qnx4_i(inode));
350 }
351 
init_once(void * foo)352 static void init_once(void *foo)
353 {
354 	struct qnx4_inode_info *ei = (struct qnx4_inode_info *) foo;
355 
356 	inode_init_once(&ei->vfs_inode);
357 }
358 
init_inodecache(void)359 static int init_inodecache(void)
360 {
361 	qnx4_inode_cachep = kmem_cache_create("qnx4_inode_cache",
362 					     sizeof(struct qnx4_inode_info),
363 					     0, (SLAB_RECLAIM_ACCOUNT|
364 						SLAB_MEM_SPREAD|SLAB_ACCOUNT),
365 					     init_once);
366 	if (qnx4_inode_cachep == NULL)
367 		return -ENOMEM;
368 	return 0;
369 }
370 
destroy_inodecache(void)371 static void destroy_inodecache(void)
372 {
373 	/*
374 	 * Make sure all delayed rcu free inodes are flushed before we
375 	 * destroy cache.
376 	 */
377 	rcu_barrier();
378 	kmem_cache_destroy(qnx4_inode_cachep);
379 }
380 
qnx4_mount(struct file_system_type * fs_type,int flags,const char * dev_name,void * data)381 static struct dentry *qnx4_mount(struct file_system_type *fs_type,
382 	int flags, const char *dev_name, void *data)
383 {
384 	return mount_bdev(fs_type, flags, dev_name, data, qnx4_fill_super);
385 }
386 
387 static struct file_system_type qnx4_fs_type = {
388 	.owner		= THIS_MODULE,
389 	.name		= "qnx4",
390 	.mount		= qnx4_mount,
391 	.kill_sb	= qnx4_kill_sb,
392 	.fs_flags	= FS_REQUIRES_DEV,
393 };
394 MODULE_ALIAS_FS("qnx4");
395 
init_qnx4_fs(void)396 static int __init init_qnx4_fs(void)
397 {
398 	int err;
399 
400 	err = init_inodecache();
401 	if (err)
402 		return err;
403 
404 	err = register_filesystem(&qnx4_fs_type);
405 	if (err) {
406 		destroy_inodecache();
407 		return err;
408 	}
409 
410 	printk(KERN_INFO "QNX4 filesystem 0.2.3 registered.\n");
411 	return 0;
412 }
413 
exit_qnx4_fs(void)414 static void __exit exit_qnx4_fs(void)
415 {
416 	unregister_filesystem(&qnx4_fs_type);
417 	destroy_inodecache();
418 }
419 
420 module_init(init_qnx4_fs)
421 module_exit(exit_qnx4_fs)
422 MODULE_LICENSE("GPL");
423 
424