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 <linux/fs_context.h>
25#include "qnx4.h"
26
27#define QNX4_VERSION  4
28#define QNX4_BMNAME   ".bitmap"
29
30static const struct super_operations qnx4_sops;
31
32static struct inode *qnx4_alloc_inode(struct super_block *sb);
33static void qnx4_free_inode(struct inode *inode);
34static int qnx4_statfs(struct dentry *, struct kstatfs *);
35static int qnx4_get_tree(struct fs_context *fc);
36
37static const struct super_operations qnx4_sops =
38{
39	.alloc_inode	= qnx4_alloc_inode,
40	.free_inode	= qnx4_free_inode,
41	.statfs		= qnx4_statfs,
42};
43
44static int qnx4_reconfigure(struct fs_context *fc)
45{
46	struct super_block *sb = fc->root->d_sb;
47	struct qnx4_sb_info *qs;
48
49	sync_filesystem(sb);
50	qs = qnx4_sb(sb);
51	qs->Version = QNX4_VERSION;
52	fc->sb_flags |= SB_RDONLY;
53	return 0;
54}
55
56static const struct fs_context_operations qnx4_context_opts = {
57	.get_tree	= qnx4_get_tree,
58	.reconfigure	= qnx4_reconfigure,
59};
60
61static int qnx4_get_block( struct inode *inode, sector_t iblock, struct buffer_head *bh, int create )
62{
63	unsigned long phys;
64
65	QNX4DEBUG((KERN_INFO "qnx4: qnx4_get_block inode=[%ld] iblock=[%ld]\n",inode->i_ino,iblock));
66
67	phys = qnx4_block_map( inode, iblock );
68	if ( phys ) {
69		// logical block is before EOF
70		map_bh(bh, inode->i_sb, phys);
71	}
72	return 0;
73}
74
75static inline u32 try_extent(qnx4_xtnt_t *extent, u32 *offset)
76{
77	u32 size = le32_to_cpu(extent->xtnt_size);
78	if (*offset < size)
79		return le32_to_cpu(extent->xtnt_blk) + *offset - 1;
80	*offset -= size;
81	return 0;
82}
83
84unsigned long qnx4_block_map( struct inode *inode, long iblock )
85{
86	int ix;
87	long i_xblk;
88	struct buffer_head *bh = NULL;
89	struct qnx4_xblk *xblk = NULL;
90	struct qnx4_inode_entry *qnx4_inode = qnx4_raw_inode(inode);
91	u16 nxtnt = le16_to_cpu(qnx4_inode->di_num_xtnts);
92	u32 offset = iblock;
93	u32 block = try_extent(&qnx4_inode->di_first_xtnt, &offset);
94
95	if (block) {
96		// iblock is in the first extent. This is easy.
97	} else {
98		// iblock is beyond first extent. We have to follow the extent chain.
99		i_xblk = le32_to_cpu(qnx4_inode->di_xblk);
100		ix = 0;
101		while ( --nxtnt > 0 ) {
102			if ( ix == 0 ) {
103				// read next xtnt block.
104				bh = sb_bread(inode->i_sb, i_xblk - 1);
105				if ( !bh ) {
106					QNX4DEBUG((KERN_ERR "qnx4: I/O error reading xtnt block [%ld])\n", i_xblk - 1));
107					return -EIO;
108				}
109				xblk = (struct qnx4_xblk*)bh->b_data;
110				if ( memcmp( xblk->xblk_signature, "IamXblk", 7 ) ) {
111					QNX4DEBUG((KERN_ERR "qnx4: block at %ld is not a valid xtnt\n", qnx4_inode->i_xblk));
112					return -EIO;
113				}
114			}
115			block = try_extent(&xblk->xblk_xtnts[ix], &offset);
116			if (block) {
117				// got it!
118				break;
119			}
120			if ( ++ix >= xblk->xblk_num_xtnts ) {
121				i_xblk = le32_to_cpu(xblk->xblk_next_xblk);
122				ix = 0;
123				brelse( bh );
124				bh = NULL;
125			}
126		}
127		if ( bh )
128			brelse( bh );
129	}
130
131	QNX4DEBUG((KERN_INFO "qnx4: mapping block %ld of inode %ld = %ld\n",iblock,inode->i_ino,block));
132	return block;
133}
134
135static int qnx4_statfs(struct dentry *dentry, struct kstatfs *buf)
136{
137	struct super_block *sb = dentry->d_sb;
138	u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
139
140	buf->f_type    = sb->s_magic;
141	buf->f_bsize   = sb->s_blocksize;
142	buf->f_blocks  = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size) * 8;
143	buf->f_bfree   = qnx4_count_free_blocks(sb);
144	buf->f_bavail  = buf->f_bfree;
145	buf->f_namelen = QNX4_NAME_MAX;
146	buf->f_fsid    = u64_to_fsid(id);
147
148	return 0;
149}
150
151/*
152 * Check the root directory of the filesystem to make sure
153 * it really _is_ a qnx4 filesystem, and to check the size
154 * of the directory entry.
155 */
156static const char *qnx4_checkroot(struct super_block *sb,
157				  struct qnx4_super_block *s)
158{
159	struct buffer_head *bh;
160	struct qnx4_inode_entry *rootdir;
161	int rd, rl;
162	int i, j;
163
164	if (s->RootDir.di_fname[0] != '/' || s->RootDir.di_fname[1] != '\0')
165		return "no qnx4 filesystem (no root dir).";
166	QNX4DEBUG((KERN_NOTICE "QNX4 filesystem found on dev %s.\n", sb->s_id));
167	rd = le32_to_cpu(s->RootDir.di_first_xtnt.xtnt_blk) - 1;
168	rl = le32_to_cpu(s->RootDir.di_first_xtnt.xtnt_size);
169	for (j = 0; j < rl; j++) {
170		bh = sb_bread(sb, rd + j);	/* root dir, first block */
171		if (bh == NULL)
172			return "unable to read root entry.";
173		rootdir = (struct qnx4_inode_entry *) bh->b_data;
174		for (i = 0; i < QNX4_INODES_PER_BLOCK; i++, rootdir++) {
175			QNX4DEBUG((KERN_INFO "rootdir entry found : [%s]\n", rootdir->di_fname));
176			if (strcmp(rootdir->di_fname, QNX4_BMNAME) != 0)
177				continue;
178			qnx4_sb(sb)->BitMap = kmemdup(rootdir,
179						      sizeof(struct qnx4_inode_entry),
180						      GFP_KERNEL);
181			brelse(bh);
182			if (!qnx4_sb(sb)->BitMap)
183				return "not enough memory for bitmap inode";
184			/* keep bitmap inode known */
185			return NULL;
186		}
187		brelse(bh);
188	}
189	return "bitmap file not found.";
190}
191
192static int qnx4_fill_super(struct super_block *s, struct fs_context *fc)
193{
194	struct buffer_head *bh;
195	struct inode *root;
196	const char *errmsg;
197	struct qnx4_sb_info *qs;
198	int silent = fc->sb_flags & SB_SILENT;
199
200	qs = kzalloc(sizeof(struct qnx4_sb_info), GFP_KERNEL);
201	if (!qs)
202		return -ENOMEM;
203	s->s_fs_info = qs;
204
205	sb_set_blocksize(s, QNX4_BLOCK_SIZE);
206
207	s->s_op = &qnx4_sops;
208	s->s_magic = QNX4_SUPER_MAGIC;
209	s->s_flags |= SB_RDONLY;	/* Yup, read-only yet */
210	s->s_time_min = 0;
211	s->s_time_max = U32_MAX;
212
213	/* Check the superblock signature. Since the qnx4 code is
214	   dangerous, we should leave as quickly as possible
215	   if we don't belong here... */
216	bh = sb_bread(s, 1);
217	if (!bh) {
218		printk(KERN_ERR "qnx4: unable to read the superblock\n");
219		return -EINVAL;
220	}
221
222 	/* check before allocating dentries, inodes, .. */
223	errmsg = qnx4_checkroot(s, (struct qnx4_super_block *) bh->b_data);
224	brelse(bh);
225	if (errmsg != NULL) {
226		if (!silent)
227			printk(KERN_ERR "qnx4: %s\n", errmsg);
228		return -EINVAL;
229	}
230
231 	/* does root not have inode number QNX4_ROOT_INO ?? */
232	root = qnx4_iget(s, QNX4_ROOT_INO * QNX4_INODES_PER_BLOCK);
233	if (IS_ERR(root)) {
234		printk(KERN_ERR "qnx4: get inode failed\n");
235		return PTR_ERR(root);
236 	}
237
238 	s->s_root = d_make_root(root);
239 	if (s->s_root == NULL)
240 		return -ENOMEM;
241
242	return 0;
243}
244
245static int qnx4_get_tree(struct fs_context *fc)
246{
247	return get_tree_bdev(fc, qnx4_fill_super);
248}
249
250static int qnx4_init_fs_context(struct fs_context *fc)
251{
252	fc->ops = &qnx4_context_opts;
253
254	return 0;
255}
256
257static void qnx4_kill_sb(struct super_block *sb)
258{
259	struct qnx4_sb_info *qs = qnx4_sb(sb);
260	kill_block_super(sb);
261	if (qs) {
262		kfree(qs->BitMap);
263		kfree(qs);
264	}
265}
266
267static int qnx4_read_folio(struct file *file, struct folio *folio)
268{
269	return block_read_full_folio(folio, qnx4_get_block);
270}
271
272static sector_t qnx4_bmap(struct address_space *mapping, sector_t block)
273{
274	return generic_block_bmap(mapping,block,qnx4_get_block);
275}
276
277static const struct address_space_operations qnx4_aops = {
278	.read_folio	= qnx4_read_folio,
279	.bmap		= qnx4_bmap
280};
281
282struct inode *qnx4_iget(struct super_block *sb, unsigned long ino)
283{
284	struct buffer_head *bh;
285	struct qnx4_inode_entry *raw_inode;
286	int block;
287	struct qnx4_inode_entry *qnx4_inode;
288	struct inode *inode;
289
290	inode = iget_locked(sb, ino);
291	if (!inode)
292		return ERR_PTR(-ENOMEM);
293	if (!(inode->i_state & I_NEW))
294		return inode;
295
296	qnx4_inode = qnx4_raw_inode(inode);
297	inode->i_mode = 0;
298
299	QNX4DEBUG((KERN_INFO "reading inode : [%d]\n", ino));
300	if (!ino) {
301		printk(KERN_ERR "qnx4: bad inode number on dev %s: %lu is "
302				"out of range\n",
303		       sb->s_id, ino);
304		iget_failed(inode);
305		return ERR_PTR(-EIO);
306	}
307	block = ino / QNX4_INODES_PER_BLOCK;
308
309	if (!(bh = sb_bread(sb, block))) {
310		printk(KERN_ERR "qnx4: major problem: unable to read inode from dev "
311		       "%s\n", sb->s_id);
312		iget_failed(inode);
313		return ERR_PTR(-EIO);
314	}
315	raw_inode = ((struct qnx4_inode_entry *) bh->b_data) +
316	    (ino % QNX4_INODES_PER_BLOCK);
317
318	inode->i_mode    = le16_to_cpu(raw_inode->di_mode);
319	i_uid_write(inode, (uid_t)le16_to_cpu(raw_inode->di_uid));
320	i_gid_write(inode, (gid_t)le16_to_cpu(raw_inode->di_gid));
321	set_nlink(inode, le16_to_cpu(raw_inode->di_nlink));
322	inode->i_size    = le32_to_cpu(raw_inode->di_size);
323	inode_set_mtime(inode, le32_to_cpu(raw_inode->di_mtime), 0);
324	inode_set_atime(inode, le32_to_cpu(raw_inode->di_atime), 0);
325	inode_set_ctime(inode, le32_to_cpu(raw_inode->di_ctime), 0);
326	inode->i_blocks  = le32_to_cpu(raw_inode->di_first_xtnt.xtnt_size);
327
328	memcpy(qnx4_inode, raw_inode, QNX4_DIR_ENTRY_SIZE);
329	if (S_ISREG(inode->i_mode)) {
330		inode->i_fop = &generic_ro_fops;
331		inode->i_mapping->a_ops = &qnx4_aops;
332		qnx4_i(inode)->mmu_private = inode->i_size;
333	} else if (S_ISDIR(inode->i_mode)) {
334		inode->i_op = &qnx4_dir_inode_operations;
335		inode->i_fop = &qnx4_dir_operations;
336	} else if (S_ISLNK(inode->i_mode)) {
337		inode->i_op = &page_symlink_inode_operations;
338		inode_nohighmem(inode);
339		inode->i_mapping->a_ops = &qnx4_aops;
340		qnx4_i(inode)->mmu_private = inode->i_size;
341	} else {
342		printk(KERN_ERR "qnx4: bad inode %lu on dev %s\n",
343			ino, sb->s_id);
344		iget_failed(inode);
345		brelse(bh);
346		return ERR_PTR(-EIO);
347	}
348	brelse(bh);
349	unlock_new_inode(inode);
350	return inode;
351}
352
353static struct kmem_cache *qnx4_inode_cachep;
354
355static struct inode *qnx4_alloc_inode(struct super_block *sb)
356{
357	struct qnx4_inode_info *ei;
358	ei = alloc_inode_sb(sb, qnx4_inode_cachep, GFP_KERNEL);
359	if (!ei)
360		return NULL;
361	return &ei->vfs_inode;
362}
363
364static void qnx4_free_inode(struct inode *inode)
365{
366	kmem_cache_free(qnx4_inode_cachep, qnx4_i(inode));
367}
368
369static void init_once(void *foo)
370{
371	struct qnx4_inode_info *ei = (struct qnx4_inode_info *) foo;
372
373	inode_init_once(&ei->vfs_inode);
374}
375
376static int init_inodecache(void)
377{
378	qnx4_inode_cachep = kmem_cache_create("qnx4_inode_cache",
379					     sizeof(struct qnx4_inode_info),
380					     0, (SLAB_RECLAIM_ACCOUNT|
381						SLAB_ACCOUNT),
382					     init_once);
383	if (qnx4_inode_cachep == NULL)
384		return -ENOMEM;
385	return 0;
386}
387
388static void destroy_inodecache(void)
389{
390	/*
391	 * Make sure all delayed rcu free inodes are flushed before we
392	 * destroy cache.
393	 */
394	rcu_barrier();
395	kmem_cache_destroy(qnx4_inode_cachep);
396}
397
398static struct file_system_type qnx4_fs_type = {
399	.owner			= THIS_MODULE,
400	.name			= "qnx4",
401	.kill_sb		= qnx4_kill_sb,
402	.fs_flags		= FS_REQUIRES_DEV,
403	.init_fs_context	= qnx4_init_fs_context,
404};
405MODULE_ALIAS_FS("qnx4");
406
407static int __init init_qnx4_fs(void)
408{
409	int err;
410
411	err = init_inodecache();
412	if (err)
413		return err;
414
415	err = register_filesystem(&qnx4_fs_type);
416	if (err) {
417		destroy_inodecache();
418		return err;
419	}
420
421	printk(KERN_INFO "QNX4 filesystem 0.2.3 registered.\n");
422	return 0;
423}
424
425static void __exit exit_qnx4_fs(void)
426{
427	unregister_filesystem(&qnx4_fs_type);
428	destroy_inodecache();
429}
430
431module_init(init_qnx4_fs)
432module_exit(exit_qnx4_fs)
433MODULE_LICENSE("GPL");
434
435