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[karo-tx-linux.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 int qnx4_get_block( struct inode *inode, sector_t iblock, struct buffer_head *bh, int create )
56 {
57         unsigned long phys;
58
59         QNX4DEBUG((KERN_INFO "qnx4: qnx4_get_block inode=[%ld] iblock=[%ld]\n",inode->i_ino,iblock));
60
61         phys = qnx4_block_map( inode, iblock );
62         if ( phys ) {
63                 // logical block is before EOF
64                 map_bh(bh, inode->i_sb, phys);
65         }
66         return 0;
67 }
68
69 static inline u32 try_extent(qnx4_xtnt_t *extent, u32 *offset)
70 {
71         u32 size = le32_to_cpu(extent->xtnt_size);
72         if (*offset < size)
73                 return le32_to_cpu(extent->xtnt_blk) + *offset - 1;
74         *offset -= size;
75         return 0;
76 }
77
78 unsigned long qnx4_block_map( struct inode *inode, long iblock )
79 {
80         int ix;
81         long i_xblk;
82         struct buffer_head *bh = NULL;
83         struct qnx4_xblk *xblk = NULL;
84         struct qnx4_inode_entry *qnx4_inode = qnx4_raw_inode(inode);
85         u16 nxtnt = le16_to_cpu(qnx4_inode->di_num_xtnts);
86         u32 offset = iblock;
87         u32 block = try_extent(&qnx4_inode->di_first_xtnt, &offset);
88
89         if (block) {
90                 // iblock is in the first extent. This is easy.
91         } else {
92                 // iblock is beyond first extent. We have to follow the extent chain.
93                 i_xblk = le32_to_cpu(qnx4_inode->di_xblk);
94                 ix = 0;
95                 while ( --nxtnt > 0 ) {
96                         if ( ix == 0 ) {
97                                 // read next xtnt block.
98                                 bh = sb_bread(inode->i_sb, i_xblk - 1);
99                                 if ( !bh ) {
100                                         QNX4DEBUG((KERN_ERR "qnx4: I/O error reading xtnt block [%ld])\n", i_xblk - 1));
101                                         return -EIO;
102                                 }
103                                 xblk = (struct qnx4_xblk*)bh->b_data;
104                                 if ( memcmp( xblk->xblk_signature, "IamXblk", 7 ) ) {
105                                         QNX4DEBUG((KERN_ERR "qnx4: block at %ld is not a valid xtnt\n", qnx4_inode->i_xblk));
106                                         return -EIO;
107                                 }
108                         }
109                         block = try_extent(&xblk->xblk_xtnts[ix], &offset);
110                         if (block) {
111                                 // got it!
112                                 break;
113                         }
114                         if ( ++ix >= xblk->xblk_num_xtnts ) {
115                                 i_xblk = le32_to_cpu(xblk->xblk_next_xblk);
116                                 ix = 0;
117                                 brelse( bh );
118                                 bh = NULL;
119                         }
120                 }
121                 if ( bh )
122                         brelse( bh );
123         }
124
125         QNX4DEBUG((KERN_INFO "qnx4: mapping block %ld of inode %ld = %ld\n",iblock,inode->i_ino,block));
126         return block;
127 }
128
129 static int qnx4_statfs(struct dentry *dentry, struct kstatfs *buf)
130 {
131         struct super_block *sb = dentry->d_sb;
132         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
133
134         buf->f_type    = sb->s_magic;
135         buf->f_bsize   = sb->s_blocksize;
136         buf->f_blocks  = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size) * 8;
137         buf->f_bfree   = qnx4_count_free_blocks(sb);
138         buf->f_bavail  = buf->f_bfree;
139         buf->f_namelen = QNX4_NAME_MAX;
140         buf->f_fsid.val[0] = (u32)id;
141         buf->f_fsid.val[1] = (u32)(id >> 32);
142
143         return 0;
144 }
145
146 /*
147  * Check the root directory of the filesystem to make sure
148  * it really _is_ a qnx4 filesystem, and to check the size
149  * of the directory entry.
150  */
151 static const char *qnx4_checkroot(struct super_block *sb)
152 {
153         struct buffer_head *bh;
154         struct qnx4_inode_entry *rootdir;
155         int rd, rl;
156         int i, j;
157
158         if (*(qnx4_sb(sb)->sb->RootDir.di_fname) != '/')
159                 return "no qnx4 filesystem (no root dir).";
160         QNX4DEBUG((KERN_NOTICE "QNX4 filesystem found on dev %s.\n", sb->s_id));
161         rd = le32_to_cpu(qnx4_sb(sb)->sb->RootDir.di_first_xtnt.xtnt_blk) - 1;
162         rl = le32_to_cpu(qnx4_sb(sb)->sb->RootDir.di_first_xtnt.xtnt_size);
163         for (j = 0; j < rl; j++) {
164                 bh = sb_bread(sb, rd + j);      /* root dir, first block */
165                 if (bh == NULL)
166                         return "unable to read root entry.";
167                 rootdir = (struct qnx4_inode_entry *) bh->b_data;
168                 for (i = 0; i < QNX4_INODES_PER_BLOCK; i++, rootdir++) {
169                         QNX4DEBUG((KERN_INFO "rootdir entry found : [%s]\n", rootdir->di_fname));
170                         if (strcmp(rootdir->di_fname, QNX4_BMNAME) != 0)
171                                 continue;
172                         qnx4_sb(sb)->BitMap = kmemdup(rootdir,
173                                                       sizeof(struct qnx4_inode_entry),
174                                                       GFP_KERNEL);
175                         brelse(bh);
176                         if (!qnx4_sb(sb)->BitMap)
177                                 return "not enough memory for bitmap inode";
178                         /* keep bitmap inode known */
179                         return NULL;
180                 }
181                 brelse(bh);
182         }
183         return "bitmap file not found.";
184 }
185
186 static int qnx4_fill_super(struct super_block *s, void *data, int silent)
187 {
188         struct buffer_head *bh;
189         struct inode *root;
190         const char *errmsg;
191         struct qnx4_sb_info *qs;
192         int ret = -EINVAL;
193
194         qs = kzalloc(sizeof(struct qnx4_sb_info), GFP_KERNEL);
195         if (!qs)
196                 return -ENOMEM;
197         s->s_fs_info = qs;
198
199         sb_set_blocksize(s, QNX4_BLOCK_SIZE);
200
201         /* Check the superblock signature. Since the qnx4 code is
202            dangerous, we should leave as quickly as possible
203            if we don't belong here... */
204         bh = sb_bread(s, 1);
205         if (!bh) {
206                 printk(KERN_ERR "qnx4: unable to read the superblock\n");
207                 goto outnobh;
208         }
209         if ( le32_to_cpup((__le32*) bh->b_data) != QNX4_SUPER_MAGIC ) {
210                 if (!silent)
211                         printk(KERN_ERR "qnx4: wrong fsid in superblock.\n");
212                 goto out;
213         }
214         s->s_op = &qnx4_sops;
215         s->s_magic = QNX4_SUPER_MAGIC;
216         s->s_flags |= MS_RDONLY;        /* Yup, read-only yet */
217         qnx4_sb(s)->sb_buf = bh;
218         qnx4_sb(s)->sb = (struct qnx4_super_block *) bh->b_data;
219
220
221         /* check before allocating dentries, inodes, .. */
222         errmsg = qnx4_checkroot(s);
223         if (errmsg != NULL) {
224                 if (!silent)
225                         printk(KERN_ERR "qnx4: %s\n", errmsg);
226                 goto out;
227         }
228
229         /* does root not have inode number QNX4_ROOT_INO ?? */
230         root = qnx4_iget(s, QNX4_ROOT_INO * QNX4_INODES_PER_BLOCK);
231         if (IS_ERR(root)) {
232                 printk(KERN_ERR "qnx4: get inode failed\n");
233                 ret = PTR_ERR(root);
234                 goto outb;
235         }
236
237         ret = -ENOMEM;
238         s->s_root = d_make_root(root);
239         if (s->s_root == NULL)
240                 goto outb;
241
242         brelse(bh);
243         return 0;
244
245       outb:
246         kfree(qs->BitMap);
247       out:
248         brelse(bh);
249       outnobh:
250         kfree(qs);
251         s->s_fs_info = NULL;
252         return ret;
253 }
254
255 static void qnx4_put_super(struct super_block *sb)
256 {
257         struct qnx4_sb_info *qs = qnx4_sb(sb);
258         kfree( qs->BitMap );
259         kfree( qs );
260         sb->s_fs_info = NULL;
261         return;
262 }
263
264 static int qnx4_readpage(struct file *file, struct page *page)
265 {
266         return block_read_full_page(page,qnx4_get_block);
267 }
268
269 static sector_t qnx4_bmap(struct address_space *mapping, sector_t block)
270 {
271         return generic_block_bmap(mapping,block,qnx4_get_block);
272 }
273 static const struct address_space_operations qnx4_aops = {
274         .readpage       = qnx4_readpage,
275         .bmap           = qnx4_bmap
276 };
277
278 struct inode *qnx4_iget(struct super_block *sb, unsigned long ino)
279 {
280         struct buffer_head *bh;
281         struct qnx4_inode_entry *raw_inode;
282         int block;
283         struct qnx4_inode_entry *qnx4_inode;
284         struct inode *inode;
285
286         inode = iget_locked(sb, ino);
287         if (!inode)
288                 return ERR_PTR(-ENOMEM);
289         if (!(inode->i_state & I_NEW))
290                 return inode;
291
292         qnx4_inode = qnx4_raw_inode(inode);
293         inode->i_mode = 0;
294
295         QNX4DEBUG((KERN_INFO "reading inode : [%d]\n", ino));
296         if (!ino) {
297                 printk(KERN_ERR "qnx4: bad inode number on dev %s: %lu is "
298                                 "out of range\n",
299                        sb->s_id, ino);
300                 iget_failed(inode);
301                 return ERR_PTR(-EIO);
302         }
303         block = ino / QNX4_INODES_PER_BLOCK;
304
305         if (!(bh = sb_bread(sb, block))) {
306                 printk(KERN_ERR "qnx4: major problem: unable to read inode from dev "
307                        "%s\n", sb->s_id);
308                 iget_failed(inode);
309                 return ERR_PTR(-EIO);
310         }
311         raw_inode = ((struct qnx4_inode_entry *) bh->b_data) +
312             (ino % QNX4_INODES_PER_BLOCK);
313
314         inode->i_mode    = le16_to_cpu(raw_inode->di_mode);
315         inode->i_uid     = (uid_t)le16_to_cpu(raw_inode->di_uid);
316         inode->i_gid     = (gid_t)le16_to_cpu(raw_inode->di_gid);
317         set_nlink(inode, le16_to_cpu(raw_inode->di_nlink));
318         inode->i_size    = le32_to_cpu(raw_inode->di_size);
319         inode->i_mtime.tv_sec   = le32_to_cpu(raw_inode->di_mtime);
320         inode->i_mtime.tv_nsec = 0;
321         inode->i_atime.tv_sec   = le32_to_cpu(raw_inode->di_atime);
322         inode->i_atime.tv_nsec = 0;
323         inode->i_ctime.tv_sec   = le32_to_cpu(raw_inode->di_ctime);
324         inode->i_ctime.tv_nsec = 0;
325         inode->i_blocks  = le32_to_cpu(raw_inode->di_first_xtnt.xtnt_size);
326
327         memcpy(qnx4_inode, raw_inode, QNX4_DIR_ENTRY_SIZE);
328         if (S_ISREG(inode->i_mode)) {
329                 inode->i_fop = &generic_ro_fops;
330                 inode->i_mapping->a_ops = &qnx4_aops;
331                 qnx4_i(inode)->mmu_private = inode->i_size;
332         } else if (S_ISDIR(inode->i_mode)) {
333                 inode->i_op = &qnx4_dir_inode_operations;
334                 inode->i_fop = &qnx4_dir_operations;
335         } else if (S_ISLNK(inode->i_mode)) {
336                 inode->i_op = &page_symlink_inode_operations;
337                 inode->i_mapping->a_ops = &qnx4_aops;
338                 qnx4_i(inode)->mmu_private = inode->i_size;
339         } else {
340                 printk(KERN_ERR "qnx4: bad inode %lu on dev %s\n",
341                         ino, sb->s_id);
342                 iget_failed(inode);
343                 brelse(bh);
344                 return ERR_PTR(-EIO);
345         }
346         brelse(bh);
347         unlock_new_inode(inode);
348         return inode;
349 }
350
351 static struct kmem_cache *qnx4_inode_cachep;
352
353 static struct inode *qnx4_alloc_inode(struct super_block *sb)
354 {
355         struct qnx4_inode_info *ei;
356         ei = kmem_cache_alloc(qnx4_inode_cachep, GFP_KERNEL);
357         if (!ei)
358                 return NULL;
359         return &ei->vfs_inode;
360 }
361
362 static void qnx4_i_callback(struct rcu_head *head)
363 {
364         struct inode *inode = container_of(head, struct inode, i_rcu);
365         kmem_cache_free(qnx4_inode_cachep, qnx4_i(inode));
366 }
367
368 static void qnx4_destroy_inode(struct inode *inode)
369 {
370         call_rcu(&inode->i_rcu, qnx4_i_callback);
371 }
372
373 static void init_once(void *foo)
374 {
375         struct qnx4_inode_info *ei = (struct qnx4_inode_info *) foo;
376
377         inode_init_once(&ei->vfs_inode);
378 }
379
380 static int init_inodecache(void)
381 {
382         qnx4_inode_cachep = kmem_cache_create("qnx4_inode_cache",
383                                              sizeof(struct qnx4_inode_info),
384                                              0, (SLAB_RECLAIM_ACCOUNT|
385                                                 SLAB_MEM_SPREAD),
386                                              init_once);
387         if (qnx4_inode_cachep == NULL)
388                 return -ENOMEM;
389         return 0;
390 }
391
392 static void destroy_inodecache(void)
393 {
394         /*
395          * Make sure all delayed rcu free inodes are flushed before we
396          * destroy cache.
397          */
398         rcu_barrier();
399         kmem_cache_destroy(qnx4_inode_cachep);
400 }
401
402 static struct dentry *qnx4_mount(struct file_system_type *fs_type,
403         int flags, const char *dev_name, void *data)
404 {
405         return mount_bdev(fs_type, flags, dev_name, data, qnx4_fill_super);
406 }
407
408 static struct file_system_type qnx4_fs_type = {
409         .owner          = THIS_MODULE,
410         .name           = "qnx4",
411         .mount          = qnx4_mount,
412         .kill_sb        = kill_block_super,
413         .fs_flags       = FS_REQUIRES_DEV,
414 };
415
416 static int __init init_qnx4_fs(void)
417 {
418         int err;
419
420         err = init_inodecache();
421         if (err)
422                 return err;
423
424         err = register_filesystem(&qnx4_fs_type);
425         if (err) {
426                 destroy_inodecache();
427                 return err;
428         }
429
430         printk(KERN_INFO "QNX4 filesystem 0.2.3 registered.\n");
431         return 0;
432 }
433
434 static void __exit exit_qnx4_fs(void)
435 {
436         unregister_filesystem(&qnx4_fs_type);
437         destroy_inodecache();
438 }
439
440 module_init(init_qnx4_fs)
441 module_exit(exit_qnx4_fs)
442 MODULE_LICENSE("GPL");
443