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
30 static const struct super_operations qnx4_sops;
31
32 static struct inode *qnx4_alloc_inode(struct super_block *sb);
33 static void qnx4_free_inode(struct inode *inode);
34 static int qnx4_statfs(struct dentry *, struct kstatfs *);
35 static int qnx4_get_tree(struct fs_context *fc);
36
37 static 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
44 static 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
56 static const struct fs_context_operations qnx4_context_opts = {
57 .get_tree = qnx4_get_tree,
58 .reconfigure = qnx4_reconfigure,
59 };
60
61 static 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
75 static 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
84 unsigned 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
135 static 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 */
156 static 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
192 static 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
245 static int qnx4_get_tree(struct fs_context *fc)
246 {
247 return get_tree_bdev(fc, qnx4_fill_super);
248 }
249
250 static int qnx4_init_fs_context(struct fs_context *fc)
251 {
252 fc->ops = &qnx4_context_opts;
253
254 return 0;
255 }
256
257 static 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
267 static int qnx4_read_folio(struct file *file, struct folio *folio)
268 {
269 return block_read_full_folio(folio, qnx4_get_block);
270 }
271
272 static sector_t qnx4_bmap(struct address_space *mapping, sector_t block)
273 {
274 return generic_block_bmap(mapping,block,qnx4_get_block);
275 }
276
277 static const struct address_space_operations qnx4_aops = {
278 .read_folio = qnx4_read_folio,
279 .bmap = qnx4_bmap
280 };
281
282 struct 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
353 static struct kmem_cache *qnx4_inode_cachep;
354
355 static 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
364 static void qnx4_free_inode(struct inode *inode)
365 {
366 kmem_cache_free(qnx4_inode_cachep, qnx4_i(inode));
367 }
368
369 static 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
376 static 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
388 static 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
398 static 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 };
405 MODULE_ALIAS_FS("qnx4");
406
407 static 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
425 static void __exit exit_qnx4_fs(void)
426 {
427 unregister_filesystem(&qnx4_fs_type);
428 destroy_inodecache();
429 }
430
431 module_init(init_qnx4_fs)
432 module_exit(exit_qnx4_fs)
433 MODULE_DESCRIPTION("QNX4 file system");
434 MODULE_LICENSE("GPL");
435
436
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