pid namespaces: introduce MS_KERNMOUNT flag
[linux-2.6] / fs / qnx4 / inode.c
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/types.h>
17 #include <linux/string.h>
18 #include <linux/errno.h>
19 #include <linux/slab.h>
20 #include <linux/fs.h>
21 #include <linux/qnx4_fs.h>
22 #include <linux/init.h>
23 #include <linux/highuid.h>
24 #include <linux/smp_lock.h>
25 #include <linux/pagemap.h>
26 #include <linux/buffer_head.h>
27 #include <linux/vfs.h>
28 #include <asm/uaccess.h>
29
30 #define QNX4_VERSION  4
31 #define QNX4_BMNAME   ".bitmap"
32
33 static const struct super_operations qnx4_sops;
34
35 #ifdef CONFIG_QNX4FS_RW
36
37 int qnx4_sync_inode(struct inode *inode)
38 {
39         int err = 0;
40 # if 0
41         struct buffer_head *bh;
42
43         bh = qnx4_update_inode(inode);
44         if (bh && buffer_dirty(bh))
45         {
46                 sync_dirty_buffer(bh);
47                 if (buffer_req(bh) && !buffer_uptodate(bh))
48                 {
49                         printk ("IO error syncing qnx4 inode [%s:%08lx]\n",
50                                 inode->i_sb->s_id, inode->i_ino);
51                         err = -1;
52                 }
53                 brelse (bh);
54         } else if (!bh) {
55                 err = -1;
56         }
57 # endif
58
59         return err;
60 }
61
62 static void qnx4_delete_inode(struct inode *inode)
63 {
64         QNX4DEBUG(("qnx4: deleting inode [%lu]\n", (unsigned long) inode->i_ino));
65         truncate_inode_pages(&inode->i_data, 0);
66         inode->i_size = 0;
67         qnx4_truncate(inode);
68         lock_kernel();
69         qnx4_free_inode(inode);
70         unlock_kernel();
71 }
72
73 static void qnx4_write_super(struct super_block *sb)
74 {
75         lock_kernel();
76         QNX4DEBUG(("qnx4: write_super\n"));
77         sb->s_dirt = 0;
78         unlock_kernel();
79 }
80
81 static int qnx4_write_inode(struct inode *inode, int unused)
82 {
83         struct qnx4_inode_entry *raw_inode;
84         int block, ino;
85         struct buffer_head *bh;
86         ino = inode->i_ino;
87
88         QNX4DEBUG(("qnx4: write inode 1.\n"));
89         if (inode->i_nlink == 0) {
90                 return 0;
91         }
92         if (!ino) {
93                 printk("qnx4: bad inode number on dev %s: %d is out of range\n",
94                        inode->i_sb->s_id, ino);
95                 return -EIO;
96         }
97         QNX4DEBUG(("qnx4: write inode 2.\n"));
98         block = ino / QNX4_INODES_PER_BLOCK;
99         lock_kernel();
100         if (!(bh = sb_bread(inode->i_sb, block))) {
101                 printk("qnx4: major problem: unable to read inode from dev "
102                        "%s\n", inode->i_sb->s_id);
103                 unlock_kernel();
104                 return -EIO;
105         }
106         raw_inode = ((struct qnx4_inode_entry *) bh->b_data) +
107             (ino % QNX4_INODES_PER_BLOCK);
108         raw_inode->di_mode  = cpu_to_le16(inode->i_mode);
109         raw_inode->di_uid   = cpu_to_le16(fs_high2lowuid(inode->i_uid));
110         raw_inode->di_gid   = cpu_to_le16(fs_high2lowgid(inode->i_gid));
111         raw_inode->di_nlink = cpu_to_le16(inode->i_nlink);
112         raw_inode->di_size  = cpu_to_le32(inode->i_size);
113         raw_inode->di_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
114         raw_inode->di_atime = cpu_to_le32(inode->i_atime.tv_sec);
115         raw_inode->di_ctime = cpu_to_le32(inode->i_ctime.tv_sec);
116         raw_inode->di_first_xtnt.xtnt_size = cpu_to_le32(inode->i_blocks);
117         mark_buffer_dirty(bh);
118         brelse(bh);
119         unlock_kernel();
120         return 0;
121 }
122
123 #endif
124
125 static void qnx4_put_super(struct super_block *sb);
126 static struct inode *qnx4_alloc_inode(struct super_block *sb);
127 static void qnx4_destroy_inode(struct inode *inode);
128 static void qnx4_read_inode(struct inode *);
129 static int qnx4_remount(struct super_block *sb, int *flags, char *data);
130 static int qnx4_statfs(struct dentry *, struct kstatfs *);
131
132 static const struct super_operations qnx4_sops =
133 {
134         .alloc_inode    = qnx4_alloc_inode,
135         .destroy_inode  = qnx4_destroy_inode,
136         .read_inode     = qnx4_read_inode,
137         .put_super      = qnx4_put_super,
138         .statfs         = qnx4_statfs,
139         .remount_fs     = qnx4_remount,
140 #ifdef CONFIG_QNX4FS_RW
141         .write_inode    = qnx4_write_inode,
142         .delete_inode   = qnx4_delete_inode,
143         .write_super    = qnx4_write_super,
144 #endif
145 };
146
147 static int qnx4_remount(struct super_block *sb, int *flags, char *data)
148 {
149         struct qnx4_sb_info *qs;
150
151         qs = qnx4_sb(sb);
152         qs->Version = QNX4_VERSION;
153 #ifndef CONFIG_QNX4FS_RW
154         *flags |= MS_RDONLY;
155 #endif
156         if (*flags & MS_RDONLY) {
157                 return 0;
158         }
159
160         mark_buffer_dirty(qs->sb_buf);
161
162         return 0;
163 }
164
165 static struct buffer_head *qnx4_getblk(struct inode *inode, int nr,
166                                        int create)
167 {
168         struct buffer_head *result = NULL;
169
170         if ( nr >= 0 )
171                 nr = qnx4_block_map( inode, nr );
172         if (nr) {
173                 result = sb_getblk(inode->i_sb, nr);
174                 return result;
175         }
176         if (!create) {
177                 return NULL;
178         }
179 #if 0
180         tmp = qnx4_new_block(inode->i_sb);
181         if (!tmp) {
182                 return NULL;
183         }
184         result = sb_getblk(inode->i_sb, tmp);
185         if (tst) {
186                 qnx4_free_block(inode->i_sb, tmp);
187                 brelse(result);
188                 goto repeat;
189         }
190         tst = tmp;
191 #endif
192         inode->i_ctime = CURRENT_TIME_SEC;
193         mark_inode_dirty(inode);
194         return result;
195 }
196
197 struct buffer_head *qnx4_bread(struct inode *inode, int block, int create)
198 {
199         struct buffer_head *bh;
200
201         bh = qnx4_getblk(inode, block, create);
202         if (!bh || buffer_uptodate(bh)) {
203                 return bh;
204         }
205         ll_rw_block(READ, 1, &bh);
206         wait_on_buffer(bh);
207         if (buffer_uptodate(bh)) {
208                 return bh;
209         }
210         brelse(bh);
211
212         return NULL;
213 }
214
215 static int qnx4_get_block( struct inode *inode, sector_t iblock, struct buffer_head *bh, int create )
216 {
217         unsigned long phys;
218
219         QNX4DEBUG(("qnx4: qnx4_get_block inode=[%ld] iblock=[%ld]\n",inode->i_ino,iblock));
220
221         phys = qnx4_block_map( inode, iblock );
222         if ( phys ) {
223                 // logical block is before EOF
224                 map_bh(bh, inode->i_sb, phys);
225         } else if ( create ) {
226                 // to be done.
227         }
228         return 0;
229 }
230
231 unsigned long qnx4_block_map( struct inode *inode, long iblock )
232 {
233         int ix;
234         long offset, i_xblk;
235         unsigned long block = 0;
236         struct buffer_head *bh = NULL;
237         struct qnx4_xblk *xblk = NULL;
238         struct qnx4_inode_entry *qnx4_inode = qnx4_raw_inode(inode);
239         u16 nxtnt = le16_to_cpu(qnx4_inode->di_num_xtnts);
240
241         if ( iblock < le32_to_cpu(qnx4_inode->di_first_xtnt.xtnt_size) ) {
242                 // iblock is in the first extent. This is easy.
243                 block = le32_to_cpu(qnx4_inode->di_first_xtnt.xtnt_blk) + iblock - 1;
244         } else {
245                 // iblock is beyond first extent. We have to follow the extent chain.
246                 i_xblk = le32_to_cpu(qnx4_inode->di_xblk);
247                 offset = iblock - le32_to_cpu(qnx4_inode->di_first_xtnt.xtnt_size);
248                 ix = 0;
249                 while ( --nxtnt > 0 ) {
250                         if ( ix == 0 ) {
251                                 // read next xtnt block.
252                                 bh = sb_bread(inode->i_sb, i_xblk - 1);
253                                 if ( !bh ) {
254                                         QNX4DEBUG(("qnx4: I/O error reading xtnt block [%ld])\n", i_xblk - 1));
255                                         return -EIO;
256                                 }
257                                 xblk = (struct qnx4_xblk*)bh->b_data;
258                                 if ( memcmp( xblk->xblk_signature, "IamXblk", 7 ) ) {
259                                         QNX4DEBUG(("qnx4: block at %ld is not a valid xtnt\n", qnx4_inode->i_xblk));
260                                         return -EIO;
261                                 }
262                         }
263                         if ( offset < le32_to_cpu(xblk->xblk_xtnts[ix].xtnt_size) ) {
264                                 // got it!
265                                 block = le32_to_cpu(xblk->xblk_xtnts[ix].xtnt_blk) + offset - 1;
266                                 break;
267                         }
268                         offset -= le32_to_cpu(xblk->xblk_xtnts[ix].xtnt_size);
269                         if ( ++ix >= xblk->xblk_num_xtnts ) {
270                                 i_xblk = le32_to_cpu(xblk->xblk_next_xblk);
271                                 ix = 0;
272                                 brelse( bh );
273                                 bh = NULL;
274                         }
275                 }
276                 if ( bh )
277                         brelse( bh );
278         }
279
280         QNX4DEBUG(("qnx4: mapping block %ld of inode %ld = %ld\n",iblock,inode->i_ino,block));
281         return block;
282 }
283
284 static int qnx4_statfs(struct dentry *dentry, struct kstatfs *buf)
285 {
286         struct super_block *sb = dentry->d_sb;
287
288         lock_kernel();
289
290         buf->f_type    = sb->s_magic;
291         buf->f_bsize   = sb->s_blocksize;
292         buf->f_blocks  = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size) * 8;
293         buf->f_bfree   = qnx4_count_free_blocks(sb);
294         buf->f_bavail  = buf->f_bfree;
295         buf->f_namelen = QNX4_NAME_MAX;
296
297         unlock_kernel();
298
299         return 0;
300 }
301
302 /*
303  * Check the root directory of the filesystem to make sure
304  * it really _is_ a qnx4 filesystem, and to check the size
305  * of the directory entry.
306  */
307 static const char *qnx4_checkroot(struct super_block *sb)
308 {
309         struct buffer_head *bh;
310         struct qnx4_inode_entry *rootdir;
311         int rd, rl;
312         int i, j;
313         int found = 0;
314
315         if (*(qnx4_sb(sb)->sb->RootDir.di_fname) != '/') {
316                 return "no qnx4 filesystem (no root dir).";
317         } else {
318                 QNX4DEBUG(("QNX4 filesystem found on dev %s.\n", sb->s_id));
319                 rd = le32_to_cpu(qnx4_sb(sb)->sb->RootDir.di_first_xtnt.xtnt_blk) - 1;
320                 rl = le32_to_cpu(qnx4_sb(sb)->sb->RootDir.di_first_xtnt.xtnt_size);
321                 for (j = 0; j < rl; j++) {
322                         bh = sb_bread(sb, rd + j);      /* root dir, first block */
323                         if (bh == NULL) {
324                                 return "unable to read root entry.";
325                         }
326                         for (i = 0; i < QNX4_INODES_PER_BLOCK; i++) {
327                                 rootdir = (struct qnx4_inode_entry *) (bh->b_data + i * QNX4_DIR_ENTRY_SIZE);
328                                 if (rootdir->di_fname != NULL) {
329                                         QNX4DEBUG(("Rootdir entry found : [%s]\n", rootdir->di_fname));
330                                         if (!strncmp(rootdir->di_fname, QNX4_BMNAME, sizeof QNX4_BMNAME)) {
331                                                 found = 1;
332                                                 qnx4_sb(sb)->BitMap = kmalloc( sizeof( struct qnx4_inode_entry ), GFP_KERNEL );
333                                                 if (!qnx4_sb(sb)->BitMap) {
334                                                         brelse (bh);
335                                                         return "not enough memory for bitmap inode";
336                                                 }
337                                                 memcpy( qnx4_sb(sb)->BitMap, rootdir, sizeof( struct qnx4_inode_entry ) );      /* keep bitmap inode known */
338                                                 break;
339                                         }
340                                 }
341                         }
342                         brelse(bh);
343                         if (found != 0) {
344                                 break;
345                         }
346                 }
347                 if (found == 0) {
348                         return "bitmap file not found.";
349                 }
350         }
351         return NULL;
352 }
353
354 static int qnx4_fill_super(struct super_block *s, void *data, int silent)
355 {
356         struct buffer_head *bh;
357         struct inode *root;
358         const char *errmsg;
359         struct qnx4_sb_info *qs;
360
361         qs = kzalloc(sizeof(struct qnx4_sb_info), GFP_KERNEL);
362         if (!qs)
363                 return -ENOMEM;
364         s->s_fs_info = qs;
365
366         sb_set_blocksize(s, QNX4_BLOCK_SIZE);
367
368         /* Check the superblock signature. Since the qnx4 code is
369            dangerous, we should leave as quickly as possible
370            if we don't belong here... */
371         bh = sb_bread(s, 1);
372         if (!bh) {
373                 printk("qnx4: unable to read the superblock\n");
374                 goto outnobh;
375         }
376         if ( le32_to_cpup((__le32*) bh->b_data) != QNX4_SUPER_MAGIC ) {
377                 if (!silent)
378                         printk("qnx4: wrong fsid in superblock.\n");
379                 goto out;
380         }
381         s->s_op = &qnx4_sops;
382         s->s_magic = QNX4_SUPER_MAGIC;
383 #ifndef CONFIG_QNX4FS_RW
384         s->s_flags |= MS_RDONLY;        /* Yup, read-only yet */
385 #endif
386         qnx4_sb(s)->sb_buf = bh;
387         qnx4_sb(s)->sb = (struct qnx4_super_block *) bh->b_data;
388
389
390         /* check before allocating dentries, inodes, .. */
391         errmsg = qnx4_checkroot(s);
392         if (errmsg != NULL) {
393                 if (!silent)
394                         printk("qnx4: %s\n", errmsg);
395                 goto out;
396         }
397
398         /* does root not have inode number QNX4_ROOT_INO ?? */
399         root = iget(s, QNX4_ROOT_INO * QNX4_INODES_PER_BLOCK);
400         if (!root) {
401                 printk("qnx4: get inode failed\n");
402                 goto out;
403         }
404
405         s->s_root = d_alloc_root(root);
406         if (s->s_root == NULL)
407                 goto outi;
408
409         brelse(bh);
410
411         return 0;
412
413       outi:
414         iput(root);
415       out:
416         brelse(bh);
417       outnobh:
418         kfree(qs);
419         s->s_fs_info = NULL;
420         return -EINVAL;
421 }
422
423 static void qnx4_put_super(struct super_block *sb)
424 {
425         struct qnx4_sb_info *qs = qnx4_sb(sb);
426         kfree( qs->BitMap );
427         kfree( qs );
428         sb->s_fs_info = NULL;
429         return;
430 }
431
432 static int qnx4_writepage(struct page *page, struct writeback_control *wbc)
433 {
434         return block_write_full_page(page,qnx4_get_block, wbc);
435 }
436
437 static int qnx4_readpage(struct file *file, struct page *page)
438 {
439         return block_read_full_page(page,qnx4_get_block);
440 }
441
442 static int qnx4_write_begin(struct file *file, struct address_space *mapping,
443                         loff_t pos, unsigned len, unsigned flags,
444                         struct page **pagep, void **fsdata)
445 {
446         struct qnx4_inode_info *qnx4_inode = qnx4_i(mapping->host);
447         *pagep = NULL;
448         return cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
449                                 qnx4_get_block,
450                                 &qnx4_inode->mmu_private);
451 }
452 static sector_t qnx4_bmap(struct address_space *mapping, sector_t block)
453 {
454         return generic_block_bmap(mapping,block,qnx4_get_block);
455 }
456 static const struct address_space_operations qnx4_aops = {
457         .readpage       = qnx4_readpage,
458         .writepage      = qnx4_writepage,
459         .sync_page      = block_sync_page,
460         .write_begin    = qnx4_write_begin,
461         .write_end      = generic_write_end,
462         .bmap           = qnx4_bmap
463 };
464
465 static void qnx4_read_inode(struct inode *inode)
466 {
467         struct buffer_head *bh;
468         struct qnx4_inode_entry *raw_inode;
469         int block, ino;
470         struct super_block *sb = inode->i_sb;
471         struct qnx4_inode_entry *qnx4_inode = qnx4_raw_inode(inode);
472
473         ino = inode->i_ino;
474         inode->i_mode = 0;
475
476         QNX4DEBUG(("Reading inode : [%d]\n", ino));
477         if (!ino) {
478                 printk("qnx4: bad inode number on dev %s: %d is out of range\n",
479                        sb->s_id, ino);
480                 return;
481         }
482         block = ino / QNX4_INODES_PER_BLOCK;
483
484         if (!(bh = sb_bread(sb, block))) {
485                 printk("qnx4: major problem: unable to read inode from dev "
486                        "%s\n", sb->s_id);
487                 return;
488         }
489         raw_inode = ((struct qnx4_inode_entry *) bh->b_data) +
490             (ino % QNX4_INODES_PER_BLOCK);
491
492         inode->i_mode    = le16_to_cpu(raw_inode->di_mode);
493         inode->i_uid     = (uid_t)le16_to_cpu(raw_inode->di_uid);
494         inode->i_gid     = (gid_t)le16_to_cpu(raw_inode->di_gid);
495         inode->i_nlink   = le16_to_cpu(raw_inode->di_nlink);
496         inode->i_size    = le32_to_cpu(raw_inode->di_size);
497         inode->i_mtime.tv_sec   = le32_to_cpu(raw_inode->di_mtime);
498         inode->i_mtime.tv_nsec = 0;
499         inode->i_atime.tv_sec   = le32_to_cpu(raw_inode->di_atime);
500         inode->i_atime.tv_nsec = 0;
501         inode->i_ctime.tv_sec   = le32_to_cpu(raw_inode->di_ctime);
502         inode->i_ctime.tv_nsec = 0;
503         inode->i_blocks  = le32_to_cpu(raw_inode->di_first_xtnt.xtnt_size);
504
505         memcpy(qnx4_inode, raw_inode, QNX4_DIR_ENTRY_SIZE);
506         if (S_ISREG(inode->i_mode)) {
507                 inode->i_op = &qnx4_file_inode_operations;
508                 inode->i_fop = &qnx4_file_operations;
509                 inode->i_mapping->a_ops = &qnx4_aops;
510                 qnx4_i(inode)->mmu_private = inode->i_size;
511         } else if (S_ISDIR(inode->i_mode)) {
512                 inode->i_op = &qnx4_dir_inode_operations;
513                 inode->i_fop = &qnx4_dir_operations;
514         } else if (S_ISLNK(inode->i_mode)) {
515                 inode->i_op = &page_symlink_inode_operations;
516                 inode->i_mapping->a_ops = &qnx4_aops;
517                 qnx4_i(inode)->mmu_private = inode->i_size;
518         } else
519                 printk("qnx4: bad inode %d on dev %s\n",ino,sb->s_id);
520         brelse(bh);
521 }
522
523 static struct kmem_cache *qnx4_inode_cachep;
524
525 static struct inode *qnx4_alloc_inode(struct super_block *sb)
526 {
527         struct qnx4_inode_info *ei;
528         ei = kmem_cache_alloc(qnx4_inode_cachep, GFP_KERNEL);
529         if (!ei)
530                 return NULL;
531         return &ei->vfs_inode;
532 }
533
534 static void qnx4_destroy_inode(struct inode *inode)
535 {
536         kmem_cache_free(qnx4_inode_cachep, qnx4_i(inode));
537 }
538
539 static void init_once(struct kmem_cache *cachep, void *foo)
540 {
541         struct qnx4_inode_info *ei = (struct qnx4_inode_info *) foo;
542
543         inode_init_once(&ei->vfs_inode);
544 }
545
546 static int init_inodecache(void)
547 {
548         qnx4_inode_cachep = kmem_cache_create("qnx4_inode_cache",
549                                              sizeof(struct qnx4_inode_info),
550                                              0, (SLAB_RECLAIM_ACCOUNT|
551                                                 SLAB_MEM_SPREAD),
552                                              init_once);
553         if (qnx4_inode_cachep == NULL)
554                 return -ENOMEM;
555         return 0;
556 }
557
558 static void destroy_inodecache(void)
559 {
560         kmem_cache_destroy(qnx4_inode_cachep);
561 }
562
563 static int qnx4_get_sb(struct file_system_type *fs_type,
564         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
565 {
566         return get_sb_bdev(fs_type, flags, dev_name, data, qnx4_fill_super,
567                            mnt);
568 }
569
570 static struct file_system_type qnx4_fs_type = {
571         .owner          = THIS_MODULE,
572         .name           = "qnx4",
573         .get_sb         = qnx4_get_sb,
574         .kill_sb        = kill_block_super,
575         .fs_flags       = FS_REQUIRES_DEV,
576 };
577
578 static int __init init_qnx4_fs(void)
579 {
580         int err;
581
582         err = init_inodecache();
583         if (err)
584                 return err;
585
586         err = register_filesystem(&qnx4_fs_type);
587         if (err) {
588                 destroy_inodecache();
589                 return err;
590         }
591
592         printk("QNX4 filesystem 0.2.3 registered.\n");
593         return 0;
594 }
595
596 static void __exit exit_qnx4_fs(void)
597 {
598         unregister_filesystem(&qnx4_fs_type);
599         destroy_inodecache();
600 }
601
602 module_init(init_qnx4_fs)
603 module_exit(exit_qnx4_fs)
604 MODULE_LICENSE("GPL");
605