Root/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
28static const struct super_operations qnx4_sops;
29
30static void qnx4_put_super(struct super_block *sb);
31static struct inode *qnx4_alloc_inode(struct super_block *sb);
32static void qnx4_destroy_inode(struct inode *inode);
33static int qnx4_remount(struct super_block *sb, int *flags, char *data);
34static int qnx4_statfs(struct dentry *, struct kstatfs *);
35
36static 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
45static 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
55static 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
69struct 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
87static 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
101unsigned 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
154static 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 */
176static 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
224static 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
293static 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
302static int qnx4_writepage(struct page *page, struct writeback_control *wbc)
303{
304    return block_write_full_page(page,qnx4_get_block, wbc);
305}
306
307static int qnx4_readpage(struct file *file, struct page *page)
308{
309    return block_read_full_page(page,qnx4_get_block);
310}
311
312static 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}
331static sector_t qnx4_bmap(struct address_space *mapping, sector_t block)
332{
333    return generic_block_bmap(mapping,block,qnx4_get_block);
334}
335static 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
343struct 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
416static struct kmem_cache *qnx4_inode_cachep;
417
418static 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
427static 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
434static void qnx4_destroy_inode(struct inode *inode)
435{
436    call_rcu(&inode->i_rcu, qnx4_i_callback);
437}
438
439static 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
446static 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
458static void destroy_inodecache(void)
459{
460    kmem_cache_destroy(qnx4_inode_cachep);
461}
462
463static 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
469static 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
477static 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
495static void __exit exit_qnx4_fs(void)
496{
497    unregister_filesystem(&qnx4_fs_type);
498    destroy_inodecache();
499}
500
501module_init(init_qnx4_fs)
502module_exit(exit_qnx4_fs)
503MODULE_LICENSE("GPL");
504
505

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