vfs: rename 'do_follow_link' to 'should_follow_link'
[linux-2.6.git] / 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/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         .write_begin    = qnx4_write_begin,
339         .write_end      = generic_write_end,
340         .bmap           = qnx4_bmap
341 };
342
343 struct inode *qnx4_iget(struct super_block *sb, unsigned long ino)
344 {
345         struct buffer_head *bh;
346         struct qnx4_inode_entry *raw_inode;
347         int block;
348         struct qnx4_inode_entry *qnx4_inode;
349         struct inode *inode;
350
351         inode = iget_locked(sb, ino);
352         if (!inode)
353                 return ERR_PTR(-ENOMEM);
354         if (!(inode->i_state & I_NEW))
355                 return inode;
356
357         qnx4_inode = qnx4_raw_inode(inode);
358         inode->i_mode = 0;
359
360         QNX4DEBUG((KERN_INFO "reading inode : [%d]\n", ino));
361         if (!ino) {
362                 printk(KERN_ERR "qnx4: bad inode number on dev %s: %lu is "
363                                 "out of range\n",
364                        sb->s_id, ino);
365                 iget_failed(inode);
366                 return ERR_PTR(-EIO);
367         }
368         block = ino / QNX4_INODES_PER_BLOCK;
369
370         if (!(bh = sb_bread(sb, block))) {
371                 printk(KERN_ERR "qnx4: major problem: unable to read inode from dev "
372                        "%s\n", sb->s_id);
373                 iget_failed(inode);
374                 return ERR_PTR(-EIO);
375         }
376         raw_inode = ((struct qnx4_inode_entry *) bh->b_data) +
377             (ino % QNX4_INODES_PER_BLOCK);
378
379         inode->i_mode    = le16_to_cpu(raw_inode->di_mode);
380         inode->i_uid     = (uid_t)le16_to_cpu(raw_inode->di_uid);
381         inode->i_gid     = (gid_t)le16_to_cpu(raw_inode->di_gid);
382         inode->i_nlink   = le16_to_cpu(raw_inode->di_nlink);
383         inode->i_size    = le32_to_cpu(raw_inode->di_size);
384         inode->i_mtime.tv_sec   = le32_to_cpu(raw_inode->di_mtime);
385         inode->i_mtime.tv_nsec = 0;
386         inode->i_atime.tv_sec   = le32_to_cpu(raw_inode->di_atime);
387         inode->i_atime.tv_nsec = 0;
388         inode->i_ctime.tv_sec   = le32_to_cpu(raw_inode->di_ctime);
389         inode->i_ctime.tv_nsec = 0;
390         inode->i_blocks  = le32_to_cpu(raw_inode->di_first_xtnt.xtnt_size);
391
392         memcpy(qnx4_inode, raw_inode, QNX4_DIR_ENTRY_SIZE);
393         if (S_ISREG(inode->i_mode)) {
394                 inode->i_fop = &generic_ro_fops;
395                 inode->i_mapping->a_ops = &qnx4_aops;
396                 qnx4_i(inode)->mmu_private = inode->i_size;
397         } else if (S_ISDIR(inode->i_mode)) {
398                 inode->i_op = &qnx4_dir_inode_operations;
399                 inode->i_fop = &qnx4_dir_operations;
400         } else if (S_ISLNK(inode->i_mode)) {
401                 inode->i_op = &page_symlink_inode_operations;
402                 inode->i_mapping->a_ops = &qnx4_aops;
403                 qnx4_i(inode)->mmu_private = inode->i_size;
404         } else {
405                 printk(KERN_ERR "qnx4: bad inode %lu on dev %s\n",
406                         ino, sb->s_id);
407                 iget_failed(inode);
408                 brelse(bh);
409                 return ERR_PTR(-EIO);
410         }
411         brelse(bh);
412         unlock_new_inode(inode);
413         return inode;
414 }
415
416 static struct kmem_cache *qnx4_inode_cachep;
417
418 static struct inode *qnx4_alloc_inode(struct super_block *sb)
419 {
420         struct qnx4_inode_info *ei;
421         ei = kmem_cache_alloc(qnx4_inode_cachep, GFP_KERNEL);
422         if (!ei)
423                 return NULL;
424         return &ei->vfs_inode;
425 }
426
427 static void qnx4_i_callback(struct rcu_head *head)
428 {
429         struct inode *inode = container_of(head, struct inode, i_rcu);
430         INIT_LIST_HEAD(&inode->i_dentry);
431         kmem_cache_free(qnx4_inode_cachep, qnx4_i(inode));
432 }
433
434 static void qnx4_destroy_inode(struct inode *inode)
435 {
436         call_rcu(&inode->i_rcu, qnx4_i_callback);
437 }
438
439 static void init_once(void *foo)
440 {
441         struct qnx4_inode_info *ei = (struct qnx4_inode_info *) foo;
442
443         inode_init_once(&ei->vfs_inode);
444 }
445
446 static int init_inodecache(void)
447 {
448         qnx4_inode_cachep = kmem_cache_create("qnx4_inode_cache",
449                                              sizeof(struct qnx4_inode_info),
450                                              0, (SLAB_RECLAIM_ACCOUNT|
451                                                 SLAB_MEM_SPREAD),
452                                              init_once);
453         if (qnx4_inode_cachep == NULL)
454                 return -ENOMEM;
455         return 0;
456 }
457
458 static void destroy_inodecache(void)
459 {
460         kmem_cache_destroy(qnx4_inode_cachep);
461 }
462
463 static struct dentry *qnx4_mount(struct file_system_type *fs_type,
464         int flags, const char *dev_name, void *data)
465 {
466         return mount_bdev(fs_type, flags, dev_name, data, qnx4_fill_super);
467 }
468
469 static struct file_system_type qnx4_fs_type = {
470         .owner          = THIS_MODULE,
471         .name           = "qnx4",
472         .mount          = qnx4_mount,
473         .kill_sb        = kill_block_super,
474         .fs_flags       = FS_REQUIRES_DEV,
475 };
476
477 static int __init init_qnx4_fs(void)
478 {
479         int err;
480
481         err = init_inodecache();
482         if (err)
483                 return err;
484
485         err = register_filesystem(&qnx4_fs_type);
486         if (err) {
487                 destroy_inodecache();
488                 return err;
489         }
490
491         printk(KERN_INFO "QNX4 filesystem 0.2.3 registered.\n");
492         return 0;
493 }
494
495 static void __exit exit_qnx4_fs(void)
496 {
497         unregister_filesystem(&qnx4_fs_type);
498         destroy_inodecache();
499 }
500
501 module_init(init_qnx4_fs)
502 module_exit(exit_qnx4_fs)
503 MODULE_LICENSE("GPL");
504