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Linux/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 struct inode *qnx4_alloc_inode(struct super_block *sb);
 31 static void qnx4_destroy_inode(struct inode *inode);
 32 static int qnx4_remount(struct super_block *sb, int *flags, char *data);
 33 static int qnx4_statfs(struct dentry *, struct kstatfs *);
 34 
 35 static const struct super_operations qnx4_sops =
 36 {
 37         .alloc_inode    = qnx4_alloc_inode,
 38         .destroy_inode  = qnx4_destroy_inode,
 39         .statfs         = qnx4_statfs,
 40         .remount_fs     = qnx4_remount,
 41 };
 42 
 43 static int qnx4_remount(struct super_block *sb, int *flags, char *data)
 44 {
 45         struct qnx4_sb_info *qs;
 46 
 47         sync_filesystem(sb);
 48         qs = qnx4_sb(sb);
 49         qs->Version = QNX4_VERSION;
 50         *flags |= MS_RDONLY;
 51         return 0;
 52 }
 53 
 54 static int qnx4_get_block( struct inode *inode, sector_t iblock, struct buffer_head *bh, int create )
 55 {
 56         unsigned long phys;
 57 
 58         QNX4DEBUG((KERN_INFO "qnx4: qnx4_get_block inode=[%ld] iblock=[%ld]\n",inode->i_ino,iblock));
 59 
 60         phys = qnx4_block_map( inode, iblock );
 61         if ( phys ) {
 62                 // logical block is before EOF
 63                 map_bh(bh, inode->i_sb, phys);
 64         }
 65         return 0;
 66 }
 67 
 68 static inline u32 try_extent(qnx4_xtnt_t *extent, u32 *offset)
 69 {
 70         u32 size = le32_to_cpu(extent->xtnt_size);
 71         if (*offset < size)
 72                 return le32_to_cpu(extent->xtnt_blk) + *offset - 1;
 73         *offset -= size;
 74         return 0;
 75 }
 76 
 77 unsigned long qnx4_block_map( struct inode *inode, long iblock )
 78 {
 79         int ix;
 80         long i_xblk;
 81         struct buffer_head *bh = NULL;
 82         struct qnx4_xblk *xblk = NULL;
 83         struct qnx4_inode_entry *qnx4_inode = qnx4_raw_inode(inode);
 84         u16 nxtnt = le16_to_cpu(qnx4_inode->di_num_xtnts);
 85         u32 offset = iblock;
 86         u32 block = try_extent(&qnx4_inode->di_first_xtnt, &offset);
 87 
 88         if (block) {
 89                 // iblock is in the first extent. This is easy.
 90         } else {
 91                 // iblock is beyond first extent. We have to follow the extent chain.
 92                 i_xblk = le32_to_cpu(qnx4_inode->di_xblk);
 93                 ix = 0;
 94                 while ( --nxtnt > 0 ) {
 95                         if ( ix == 0 ) {
 96                                 // read next xtnt block.
 97                                 bh = sb_bread(inode->i_sb, i_xblk - 1);
 98                                 if ( !bh ) {
 99                                         QNX4DEBUG((KERN_ERR "qnx4: I/O error reading xtnt block [%ld])\n", i_xblk - 1));
100                                         return -EIO;
101                                 }
102                                 xblk = (struct qnx4_xblk*)bh->b_data;
103                                 if ( memcmp( xblk->xblk_signature, "IamXblk", 7 ) ) {
104                                         QNX4DEBUG((KERN_ERR "qnx4: block at %ld is not a valid xtnt\n", qnx4_inode->i_xblk));
105                                         return -EIO;
106                                 }
107                         }
108                         block = try_extent(&xblk->xblk_xtnts[ix], &offset);
109                         if (block) {
110                                 // got it!
111                                 break;
112                         }
113                         if ( ++ix >= xblk->xblk_num_xtnts ) {
114                                 i_xblk = le32_to_cpu(xblk->xblk_next_xblk);
115                                 ix = 0;
116                                 brelse( bh );
117                                 bh = NULL;
118                         }
119                 }
120                 if ( bh )
121                         brelse( bh );
122         }
123 
124         QNX4DEBUG((KERN_INFO "qnx4: mapping block %ld of inode %ld = %ld\n",iblock,inode->i_ino,block));
125         return block;
126 }
127 
128 static int qnx4_statfs(struct dentry *dentry, struct kstatfs *buf)
129 {
130         struct super_block *sb = dentry->d_sb;
131         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
132 
133         buf->f_type    = sb->s_magic;
134         buf->f_bsize   = sb->s_blocksize;
135         buf->f_blocks  = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size) * 8;
136         buf->f_bfree   = qnx4_count_free_blocks(sb);
137         buf->f_bavail  = buf->f_bfree;
138         buf->f_namelen = QNX4_NAME_MAX;
139         buf->f_fsid.val[0] = (u32)id;
140         buf->f_fsid.val[1] = (u32)(id >> 32);
141 
142         return 0;
143 }
144 
145 /*
146  * Check the root directory of the filesystem to make sure
147  * it really _is_ a qnx4 filesystem, and to check the size
148  * of the directory entry.
149  */
150 static const char *qnx4_checkroot(struct super_block *sb,
151                                   struct qnx4_super_block *s)
152 {
153         struct buffer_head *bh;
154         struct qnx4_inode_entry *rootdir;
155         int rd, rl;
156         int i, j;
157 
158         if (s->RootDir.di_fname[0] != '/' || s->RootDir.di_fname[1] != '\0')
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(s->RootDir.di_first_xtnt.xtnt_blk) - 1;
162         rl = le32_to_cpu(s->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 
193         qs = kzalloc(sizeof(struct qnx4_sb_info), GFP_KERNEL);
194         if (!qs)
195                 return -ENOMEM;
196         s->s_fs_info = qs;
197 
198         sb_set_blocksize(s, QNX4_BLOCK_SIZE);
199 
200         s->s_op = &qnx4_sops;
201         s->s_magic = QNX4_SUPER_MAGIC;
202         s->s_flags |= MS_RDONLY;        /* Yup, read-only yet */
203 
204         /* Check the superblock signature. Since the qnx4 code is
205            dangerous, we should leave as quickly as possible
206            if we don't belong here... */
207         bh = sb_bread(s, 1);
208         if (!bh) {
209                 printk(KERN_ERR "qnx4: unable to read the superblock\n");
210                 return -EINVAL;
211         }
212 
213         /* check before allocating dentries, inodes, .. */
214         errmsg = qnx4_checkroot(s, (struct qnx4_super_block *) bh->b_data);
215         brelse(bh);
216         if (errmsg != NULL) {
217                 if (!silent)
218                         printk(KERN_ERR "qnx4: %s\n", errmsg);
219                 return -EINVAL;
220         }
221 
222         /* does root not have inode number QNX4_ROOT_INO ?? */
223         root = qnx4_iget(s, QNX4_ROOT_INO * QNX4_INODES_PER_BLOCK);
224         if (IS_ERR(root)) {
225                 printk(KERN_ERR "qnx4: get inode failed\n");
226                 return PTR_ERR(root);
227         }
228 
229         s->s_root = d_make_root(root);
230         if (s->s_root == NULL)
231                 return -ENOMEM;
232 
233         return 0;
234 }
235 
236 static void qnx4_kill_sb(struct super_block *sb)
237 {
238         struct qnx4_sb_info *qs = qnx4_sb(sb);
239         kill_block_super(sb);
240         if (qs) {
241                 kfree(qs->BitMap);
242                 kfree(qs);
243         }
244 }
245 
246 static int qnx4_readpage(struct file *file, struct page *page)
247 {
248         return block_read_full_page(page,qnx4_get_block);
249 }
250 
251 static sector_t qnx4_bmap(struct address_space *mapping, sector_t block)
252 {
253         return generic_block_bmap(mapping,block,qnx4_get_block);
254 }
255 static const struct address_space_operations qnx4_aops = {
256         .readpage       = qnx4_readpage,
257         .bmap           = qnx4_bmap
258 };
259 
260 struct inode *qnx4_iget(struct super_block *sb, unsigned long ino)
261 {
262         struct buffer_head *bh;
263         struct qnx4_inode_entry *raw_inode;
264         int block;
265         struct qnx4_inode_entry *qnx4_inode;
266         struct inode *inode;
267 
268         inode = iget_locked(sb, ino);
269         if (!inode)
270                 return ERR_PTR(-ENOMEM);
271         if (!(inode->i_state & I_NEW))
272                 return inode;
273 
274         qnx4_inode = qnx4_raw_inode(inode);
275         inode->i_mode = 0;
276 
277         QNX4DEBUG((KERN_INFO "reading inode : [%d]\n", ino));
278         if (!ino) {
279                 printk(KERN_ERR "qnx4: bad inode number on dev %s: %lu is "
280                                 "out of range\n",
281                        sb->s_id, ino);
282                 iget_failed(inode);
283                 return ERR_PTR(-EIO);
284         }
285         block = ino / QNX4_INODES_PER_BLOCK;
286 
287         if (!(bh = sb_bread(sb, block))) {
288                 printk(KERN_ERR "qnx4: major problem: unable to read inode from dev "
289                        "%s\n", sb->s_id);
290                 iget_failed(inode);
291                 return ERR_PTR(-EIO);
292         }
293         raw_inode = ((struct qnx4_inode_entry *) bh->b_data) +
294             (ino % QNX4_INODES_PER_BLOCK);
295 
296         inode->i_mode    = le16_to_cpu(raw_inode->di_mode);
297         i_uid_write(inode, (uid_t)le16_to_cpu(raw_inode->di_uid));
298         i_gid_write(inode, (gid_t)le16_to_cpu(raw_inode->di_gid));
299         set_nlink(inode, le16_to_cpu(raw_inode->di_nlink));
300         inode->i_size    = le32_to_cpu(raw_inode->di_size);
301         inode->i_mtime.tv_sec   = le32_to_cpu(raw_inode->di_mtime);
302         inode->i_mtime.tv_nsec = 0;
303         inode->i_atime.tv_sec   = le32_to_cpu(raw_inode->di_atime);
304         inode->i_atime.tv_nsec = 0;
305         inode->i_ctime.tv_sec   = le32_to_cpu(raw_inode->di_ctime);
306         inode->i_ctime.tv_nsec = 0;
307         inode->i_blocks  = le32_to_cpu(raw_inode->di_first_xtnt.xtnt_size);
308 
309         memcpy(qnx4_inode, raw_inode, QNX4_DIR_ENTRY_SIZE);
310         if (S_ISREG(inode->i_mode)) {
311                 inode->i_fop = &generic_ro_fops;
312                 inode->i_mapping->a_ops = &qnx4_aops;
313                 qnx4_i(inode)->mmu_private = inode->i_size;
314         } else if (S_ISDIR(inode->i_mode)) {
315                 inode->i_op = &qnx4_dir_inode_operations;
316                 inode->i_fop = &qnx4_dir_operations;
317         } else if (S_ISLNK(inode->i_mode)) {
318                 inode->i_op = &page_symlink_inode_operations;
319                 inode->i_mapping->a_ops = &qnx4_aops;
320                 qnx4_i(inode)->mmu_private = inode->i_size;
321         } else {
322                 printk(KERN_ERR "qnx4: bad inode %lu on dev %s\n",
323                         ino, sb->s_id);
324                 iget_failed(inode);
325                 brelse(bh);
326                 return ERR_PTR(-EIO);
327         }
328         brelse(bh);
329         unlock_new_inode(inode);
330         return inode;
331 }
332 
333 static struct kmem_cache *qnx4_inode_cachep;
334 
335 static struct inode *qnx4_alloc_inode(struct super_block *sb)
336 {
337         struct qnx4_inode_info *ei;
338         ei = kmem_cache_alloc(qnx4_inode_cachep, GFP_KERNEL);
339         if (!ei)
340                 return NULL;
341         return &ei->vfs_inode;
342 }
343 
344 static void qnx4_i_callback(struct rcu_head *head)
345 {
346         struct inode *inode = container_of(head, struct inode, i_rcu);
347         kmem_cache_free(qnx4_inode_cachep, qnx4_i(inode));
348 }
349 
350 static void qnx4_destroy_inode(struct inode *inode)
351 {
352         call_rcu(&inode->i_rcu, qnx4_i_callback);
353 }
354 
355 static void init_once(void *foo)
356 {
357         struct qnx4_inode_info *ei = (struct qnx4_inode_info *) foo;
358 
359         inode_init_once(&ei->vfs_inode);
360 }
361 
362 static int init_inodecache(void)
363 {
364         qnx4_inode_cachep = kmem_cache_create("qnx4_inode_cache",
365                                              sizeof(struct qnx4_inode_info),
366                                              0, (SLAB_RECLAIM_ACCOUNT|
367                                                 SLAB_MEM_SPREAD),
368                                              init_once);
369         if (qnx4_inode_cachep == NULL)
370                 return -ENOMEM;
371         return 0;
372 }
373 
374 static void destroy_inodecache(void)
375 {
376         /*
377          * Make sure all delayed rcu free inodes are flushed before we
378          * destroy cache.
379          */
380         rcu_barrier();
381         kmem_cache_destroy(qnx4_inode_cachep);
382 }
383 
384 static struct dentry *qnx4_mount(struct file_system_type *fs_type,
385         int flags, const char *dev_name, void *data)
386 {
387         return mount_bdev(fs_type, flags, dev_name, data, qnx4_fill_super);
388 }
389 
390 static struct file_system_type qnx4_fs_type = {
391         .owner          = THIS_MODULE,
392         .name           = "qnx4",
393         .mount          = qnx4_mount,
394         .kill_sb        = qnx4_kill_sb,
395         .fs_flags       = FS_REQUIRES_DEV,
396 };
397 MODULE_ALIAS_FS("qnx4");
398 
399 static int __init init_qnx4_fs(void)
400 {
401         int err;
402 
403         err = init_inodecache();
404         if (err)
405                 return err;
406 
407         err = register_filesystem(&qnx4_fs_type);
408         if (err) {
409                 destroy_inodecache();
410                 return err;
411         }
412 
413         printk(KERN_INFO "QNX4 filesystem 0.2.3 registered.\n");
414         return 0;
415 }
416 
417 static void __exit exit_qnx4_fs(void)
418 {
419         unregister_filesystem(&qnx4_fs_type);
420         destroy_inodecache();
421 }
422 
423 module_init(init_qnx4_fs)
424 module_exit(exit_qnx4_fs)
425 MODULE_LICENSE("GPL");
426 
427 

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