switch open-coded instances of d_make_root() to new helper
[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
183         if (*(qnx4_sb(sb)->sb->RootDir.di_fname) != '/')
184                 return "no qnx4 filesystem (no root dir).";
185         QNX4DEBUG((KERN_NOTICE "QNX4 filesystem found on dev %s.\n", sb->s_id));
186         rd = le32_to_cpu(qnx4_sb(sb)->sb->RootDir.di_first_xtnt.xtnt_blk) - 1;
187         rl = le32_to_cpu(qnx4_sb(sb)->sb->RootDir.di_first_xtnt.xtnt_size);
188         for (j = 0; j < rl; j++) {
189                 bh = sb_bread(sb, rd + j);      /* root dir, first block */
190                 if (bh == NULL)
191                         return "unable to read root entry.";
192                 rootdir = (struct qnx4_inode_entry *) bh->b_data;
193                 for (i = 0; i < QNX4_INODES_PER_BLOCK; i++, rootdir++) {
194                         QNX4DEBUG((KERN_INFO "rootdir entry found : [%s]\n", rootdir->di_fname));
195                         if (strcmp(rootdir->di_fname, QNX4_BMNAME) != 0)
196                                 continue;
197                         qnx4_sb(sb)->BitMap = kmemdup(rootdir,
198                                                       sizeof(struct qnx4_inode_entry),
199                                                       GFP_KERNEL);
200                         brelse(bh);
201                         if (!qnx4_sb(sb)->BitMap)
202                                 return "not enough memory for bitmap inode";
203                         /* keep bitmap inode known */
204                         return NULL;
205                 }
206                 brelse(bh);
207         }
208         return "bitmap file not found.";
209 }
210
211 static int qnx4_fill_super(struct super_block *s, void *data, int silent)
212 {
213         struct buffer_head *bh;
214         struct inode *root;
215         const char *errmsg;
216         struct qnx4_sb_info *qs;
217         int ret = -EINVAL;
218
219         qs = kzalloc(sizeof(struct qnx4_sb_info), GFP_KERNEL);
220         if (!qs)
221                 return -ENOMEM;
222         s->s_fs_info = qs;
223
224         sb_set_blocksize(s, QNX4_BLOCK_SIZE);
225
226         /* Check the superblock signature. Since the qnx4 code is
227            dangerous, we should leave as quickly as possible
228            if we don't belong here... */
229         bh = sb_bread(s, 1);
230         if (!bh) {
231                 printk(KERN_ERR "qnx4: unable to read the superblock\n");
232                 goto outnobh;
233         }
234         if ( le32_to_cpup((__le32*) bh->b_data) != QNX4_SUPER_MAGIC ) {
235                 if (!silent)
236                         printk(KERN_ERR "qnx4: wrong fsid in superblock.\n");
237                 goto out;
238         }
239         s->s_op = &qnx4_sops;
240         s->s_magic = QNX4_SUPER_MAGIC;
241         s->s_flags |= MS_RDONLY;        /* Yup, read-only yet */
242         qnx4_sb(s)->sb_buf = bh;
243         qnx4_sb(s)->sb = (struct qnx4_super_block *) bh->b_data;
244
245
246         /* check before allocating dentries, inodes, .. */
247         errmsg = qnx4_checkroot(s);
248         if (errmsg != NULL) {
249                 if (!silent)
250                         printk(KERN_ERR "qnx4: %s\n", errmsg);
251                 goto out;
252         }
253
254         /* does root not have inode number QNX4_ROOT_INO ?? */
255         root = qnx4_iget(s, QNX4_ROOT_INO * QNX4_INODES_PER_BLOCK);
256         if (IS_ERR(root)) {
257                 printk(KERN_ERR "qnx4: get inode failed\n");
258                 ret = PTR_ERR(root);
259                 goto outb;
260         }
261
262         ret = -ENOMEM;
263         s->s_root = d_make_root(root);
264         if (s->s_root == NULL)
265                 goto outb;
266
267         brelse(bh);
268         return 0;
269
270       outb:
271         kfree(qs->BitMap);
272       out:
273         brelse(bh);
274       outnobh:
275         kfree(qs);
276         s->s_fs_info = NULL;
277         return ret;
278 }
279
280 static void qnx4_put_super(struct super_block *sb)
281 {
282         struct qnx4_sb_info *qs = qnx4_sb(sb);
283         kfree( qs->BitMap );
284         kfree( qs );
285         sb->s_fs_info = NULL;
286         return;
287 }
288
289 static int qnx4_writepage(struct page *page, struct writeback_control *wbc)
290 {
291         return block_write_full_page(page,qnx4_get_block, wbc);
292 }
293
294 static int qnx4_readpage(struct file *file, struct page *page)
295 {
296         return block_read_full_page(page,qnx4_get_block);
297 }
298
299 static int qnx4_write_begin(struct file *file, struct address_space *mapping,
300                         loff_t pos, unsigned len, unsigned flags,
301                         struct page **pagep, void **fsdata)
302 {
303         struct qnx4_inode_info *qnx4_inode = qnx4_i(mapping->host);
304         int ret;
305
306         *pagep = NULL;
307         ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
308                                 qnx4_get_block,
309                                 &qnx4_inode->mmu_private);
310         if (unlikely(ret)) {
311                 loff_t isize = mapping->host->i_size;
312                 if (pos + len > isize)
313                         vmtruncate(mapping->host, isize);
314         }
315
316         return ret;
317 }
318 static sector_t qnx4_bmap(struct address_space *mapping, sector_t block)
319 {
320         return generic_block_bmap(mapping,block,qnx4_get_block);
321 }
322 static const struct address_space_operations qnx4_aops = {
323         .readpage       = qnx4_readpage,
324         .writepage      = qnx4_writepage,
325         .write_begin    = qnx4_write_begin,
326         .write_end      = generic_write_end,
327         .bmap           = qnx4_bmap
328 };
329
330 struct inode *qnx4_iget(struct super_block *sb, unsigned long ino)
331 {
332         struct buffer_head *bh;
333         struct qnx4_inode_entry *raw_inode;
334         int block;
335         struct qnx4_inode_entry *qnx4_inode;
336         struct inode *inode;
337
338         inode = iget_locked(sb, ino);
339         if (!inode)
340                 return ERR_PTR(-ENOMEM);
341         if (!(inode->i_state & I_NEW))
342                 return inode;
343
344         qnx4_inode = qnx4_raw_inode(inode);
345         inode->i_mode = 0;
346
347         QNX4DEBUG((KERN_INFO "reading inode : [%d]\n", ino));
348         if (!ino) {
349                 printk(KERN_ERR "qnx4: bad inode number on dev %s: %lu is "
350                                 "out of range\n",
351                        sb->s_id, ino);
352                 iget_failed(inode);
353                 return ERR_PTR(-EIO);
354         }
355         block = ino / QNX4_INODES_PER_BLOCK;
356
357         if (!(bh = sb_bread(sb, block))) {
358                 printk(KERN_ERR "qnx4: major problem: unable to read inode from dev "
359                        "%s\n", sb->s_id);
360                 iget_failed(inode);
361                 return ERR_PTR(-EIO);
362         }
363         raw_inode = ((struct qnx4_inode_entry *) bh->b_data) +
364             (ino % QNX4_INODES_PER_BLOCK);
365
366         inode->i_mode    = le16_to_cpu(raw_inode->di_mode);
367         inode->i_uid     = (uid_t)le16_to_cpu(raw_inode->di_uid);
368         inode->i_gid     = (gid_t)le16_to_cpu(raw_inode->di_gid);
369         set_nlink(inode, le16_to_cpu(raw_inode->di_nlink));
370         inode->i_size    = le32_to_cpu(raw_inode->di_size);
371         inode->i_mtime.tv_sec   = le32_to_cpu(raw_inode->di_mtime);
372         inode->i_mtime.tv_nsec = 0;
373         inode->i_atime.tv_sec   = le32_to_cpu(raw_inode->di_atime);
374         inode->i_atime.tv_nsec = 0;
375         inode->i_ctime.tv_sec   = le32_to_cpu(raw_inode->di_ctime);
376         inode->i_ctime.tv_nsec = 0;
377         inode->i_blocks  = le32_to_cpu(raw_inode->di_first_xtnt.xtnt_size);
378
379         memcpy(qnx4_inode, raw_inode, QNX4_DIR_ENTRY_SIZE);
380         if (S_ISREG(inode->i_mode)) {
381                 inode->i_fop = &generic_ro_fops;
382                 inode->i_mapping->a_ops = &qnx4_aops;
383                 qnx4_i(inode)->mmu_private = inode->i_size;
384         } else if (S_ISDIR(inode->i_mode)) {
385                 inode->i_op = &qnx4_dir_inode_operations;
386                 inode->i_fop = &qnx4_dir_operations;
387         } else if (S_ISLNK(inode->i_mode)) {
388                 inode->i_op = &page_symlink_inode_operations;
389                 inode->i_mapping->a_ops = &qnx4_aops;
390                 qnx4_i(inode)->mmu_private = inode->i_size;
391         } else {
392                 printk(KERN_ERR "qnx4: bad inode %lu on dev %s\n",
393                         ino, sb->s_id);
394                 iget_failed(inode);
395                 brelse(bh);
396                 return ERR_PTR(-EIO);
397         }
398         brelse(bh);
399         unlock_new_inode(inode);
400         return inode;
401 }
402
403 static struct kmem_cache *qnx4_inode_cachep;
404
405 static struct inode *qnx4_alloc_inode(struct super_block *sb)
406 {
407         struct qnx4_inode_info *ei;
408         ei = kmem_cache_alloc(qnx4_inode_cachep, GFP_KERNEL);
409         if (!ei)
410                 return NULL;
411         return &ei->vfs_inode;
412 }
413
414 static void qnx4_i_callback(struct rcu_head *head)
415 {
416         struct inode *inode = container_of(head, struct inode, i_rcu);
417         kmem_cache_free(qnx4_inode_cachep, qnx4_i(inode));
418 }
419
420 static void qnx4_destroy_inode(struct inode *inode)
421 {
422         call_rcu(&inode->i_rcu, qnx4_i_callback);
423 }
424
425 static void init_once(void *foo)
426 {
427         struct qnx4_inode_info *ei = (struct qnx4_inode_info *) foo;
428
429         inode_init_once(&ei->vfs_inode);
430 }
431
432 static int init_inodecache(void)
433 {
434         qnx4_inode_cachep = kmem_cache_create("qnx4_inode_cache",
435                                              sizeof(struct qnx4_inode_info),
436                                              0, (SLAB_RECLAIM_ACCOUNT|
437                                                 SLAB_MEM_SPREAD),
438                                              init_once);
439         if (qnx4_inode_cachep == NULL)
440                 return -ENOMEM;
441         return 0;
442 }
443
444 static void destroy_inodecache(void)
445 {
446         kmem_cache_destroy(qnx4_inode_cachep);
447 }
448
449 static struct dentry *qnx4_mount(struct file_system_type *fs_type,
450         int flags, const char *dev_name, void *data)
451 {
452         return mount_bdev(fs_type, flags, dev_name, data, qnx4_fill_super);
453 }
454
455 static struct file_system_type qnx4_fs_type = {
456         .owner          = THIS_MODULE,
457         .name           = "qnx4",
458         .mount          = qnx4_mount,
459         .kill_sb        = kill_block_super,
460         .fs_flags       = FS_REQUIRES_DEV,
461 };
462
463 static int __init init_qnx4_fs(void)
464 {
465         int err;
466
467         err = init_inodecache();
468         if (err)
469                 return err;
470
471         err = register_filesystem(&qnx4_fs_type);
472         if (err) {
473                 destroy_inodecache();
474                 return err;
475         }
476
477         printk(KERN_INFO "QNX4 filesystem 0.2.3 registered.\n");
478         return 0;
479 }
480
481 static void __exit exit_qnx4_fs(void)
482 {
483         unregister_filesystem(&qnx4_fs_type);
484         destroy_inodecache();
485 }
486
487 module_init(init_qnx4_fs)
488 module_exit(exit_qnx4_fs)
489 MODULE_LICENSE("GPL");
490