linux/fs/qnx4/inode.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * QNX4 file system, Linux implementation.
   4 *
   5 * Version : 0.2.1
   6 *
   7 * Using parts of the xiafs filesystem.
   8 *
   9 * History :
  10 *
  11 * 01-06-1998 by Richard Frowijn : first release.
  12 * 20-06-1998 by Frank Denis : Linux 2.1.99+ support, boot signature, misc.
  13 * 30-06-1998 by Frank Denis : first step to write inodes.
  14 */
  15
  16#include <linux/module.h>
  17#include <linux/init.h>
  18#include <linux/slab.h>
  19#include <linux/highuid.h>
  20#include <linux/pagemap.h>
  21#include <linux/buffer_head.h>
  22#include <linux/writeback.h>
  23#include <linux/statfs.h>
  24#include "qnx4.h"
  25
  26#define QNX4_VERSION  4
  27#define QNX4_BMNAME   ".bitmap"
  28
  29static const struct super_operations qnx4_sops;
  30
  31static struct inode *qnx4_alloc_inode(struct super_block *sb);
  32static void qnx4_free_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        .free_inode     = qnx4_free_inode,
  40        .statfs         = qnx4_statfs,
  41        .remount_fs     = qnx4_remount,
  42};
  43
  44static int qnx4_remount(struct super_block *sb, int *flags, char *data)
  45{
  46        struct qnx4_sb_info *qs;
  47
  48        sync_filesystem(sb);
  49        qs = qnx4_sb(sb);
  50        qs->Version = QNX4_VERSION;
  51        *flags |= SB_RDONLY;
  52        return 0;
  53}
  54
  55static 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
  69static 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
  78unsigned 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
 129static 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 */
 151static const char *qnx4_checkroot(struct super_block *sb,
 152                                  struct qnx4_super_block *s)
 153{
 154        struct buffer_head *bh;
 155        struct qnx4_inode_entry *rootdir;
 156        int rd, rl;
 157        int i, j;
 158
 159        if (s->RootDir.di_fname[0] != '/' || s->RootDir.di_fname[1] != '\0')
 160                return "no qnx4 filesystem (no root dir).";
 161        QNX4DEBUG((KERN_NOTICE "QNX4 filesystem found on dev %s.\n", sb->s_id));
 162        rd = le32_to_cpu(s->RootDir.di_first_xtnt.xtnt_blk) - 1;
 163        rl = le32_to_cpu(s->RootDir.di_first_xtnt.xtnt_size);
 164        for (j = 0; j < rl; j++) {
 165                bh = sb_bread(sb, rd + j);      /* root dir, first block */
 166                if (bh == NULL)
 167                        return "unable to read root entry.";
 168                rootdir = (struct qnx4_inode_entry *) bh->b_data;
 169                for (i = 0; i < QNX4_INODES_PER_BLOCK; i++, rootdir++) {
 170                        QNX4DEBUG((KERN_INFO "rootdir entry found : [%s]\n", rootdir->di_fname));
 171                        if (strcmp(rootdir->di_fname, QNX4_BMNAME) != 0)
 172                                continue;
 173                        qnx4_sb(sb)->BitMap = kmemdup(rootdir,
 174                                                      sizeof(struct qnx4_inode_entry),
 175                                                      GFP_KERNEL);
 176                        brelse(bh);
 177                        if (!qnx4_sb(sb)->BitMap)
 178                                return "not enough memory for bitmap inode";
 179                        /* keep bitmap inode known */
 180                        return NULL;
 181                }
 182                brelse(bh);
 183        }
 184        return "bitmap file not found.";
 185}
 186
 187static int qnx4_fill_super(struct super_block *s, void *data, int silent)
 188{
 189        struct buffer_head *bh;
 190        struct inode *root;
 191        const char *errmsg;
 192        struct qnx4_sb_info *qs;
 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        s->s_op = &qnx4_sops;
 202        s->s_magic = QNX4_SUPER_MAGIC;
 203        s->s_flags |= SB_RDONLY;        /* Yup, read-only yet */
 204        s->s_time_min = 0;
 205        s->s_time_max = U32_MAX;
 206
 207        /* Check the superblock signature. Since the qnx4 code is
 208           dangerous, we should leave as quickly as possible
 209           if we don't belong here... */
 210        bh = sb_bread(s, 1);
 211        if (!bh) {
 212                printk(KERN_ERR "qnx4: unable to read the superblock\n");
 213                return -EINVAL;
 214        }
 215
 216        /* check before allocating dentries, inodes, .. */
 217        errmsg = qnx4_checkroot(s, (struct qnx4_super_block *) bh->b_data);
 218        brelse(bh);
 219        if (errmsg != NULL) {
 220                if (!silent)
 221                        printk(KERN_ERR "qnx4: %s\n", errmsg);
 222                return -EINVAL;
 223        }
 224
 225        /* does root not have inode number QNX4_ROOT_INO ?? */
 226        root = qnx4_iget(s, QNX4_ROOT_INO * QNX4_INODES_PER_BLOCK);
 227        if (IS_ERR(root)) {
 228                printk(KERN_ERR "qnx4: get inode failed\n");
 229                return PTR_ERR(root);
 230        }
 231
 232        s->s_root = d_make_root(root);
 233        if (s->s_root == NULL)
 234                return -ENOMEM;
 235
 236        return 0;
 237}
 238
 239static void qnx4_kill_sb(struct super_block *sb)
 240{
 241        struct qnx4_sb_info *qs = qnx4_sb(sb);
 242        kill_block_super(sb);
 243        if (qs) {
 244                kfree(qs->BitMap);
 245                kfree(qs);
 246        }
 247}
 248
 249static int qnx4_readpage(struct file *file, struct page *page)
 250{
 251        return block_read_full_page(page,qnx4_get_block);
 252}
 253
 254static sector_t qnx4_bmap(struct address_space *mapping, sector_t block)
 255{
 256        return generic_block_bmap(mapping,block,qnx4_get_block);
 257}
 258static const struct address_space_operations qnx4_aops = {
 259        .readpage       = qnx4_readpage,
 260        .bmap           = qnx4_bmap
 261};
 262
 263struct inode *qnx4_iget(struct super_block *sb, unsigned long ino)
 264{
 265        struct buffer_head *bh;
 266        struct qnx4_inode_entry *raw_inode;
 267        int block;
 268        struct qnx4_inode_entry *qnx4_inode;
 269        struct inode *inode;
 270
 271        inode = iget_locked(sb, ino);
 272        if (!inode)
 273                return ERR_PTR(-ENOMEM);
 274        if (!(inode->i_state & I_NEW))
 275                return inode;
 276
 277        qnx4_inode = qnx4_raw_inode(inode);
 278        inode->i_mode = 0;
 279
 280        QNX4DEBUG((KERN_INFO "reading inode : [%d]\n", ino));
 281        if (!ino) {
 282                printk(KERN_ERR "qnx4: bad inode number on dev %s: %lu is "
 283                                "out of range\n",
 284                       sb->s_id, ino);
 285                iget_failed(inode);
 286                return ERR_PTR(-EIO);
 287        }
 288        block = ino / QNX4_INODES_PER_BLOCK;
 289
 290        if (!(bh = sb_bread(sb, block))) {
 291                printk(KERN_ERR "qnx4: major problem: unable to read inode from dev "
 292                       "%s\n", sb->s_id);
 293                iget_failed(inode);
 294                return ERR_PTR(-EIO);
 295        }
 296        raw_inode = ((struct qnx4_inode_entry *) bh->b_data) +
 297            (ino % QNX4_INODES_PER_BLOCK);
 298
 299        inode->i_mode    = le16_to_cpu(raw_inode->di_mode);
 300        i_uid_write(inode, (uid_t)le16_to_cpu(raw_inode->di_uid));
 301        i_gid_write(inode, (gid_t)le16_to_cpu(raw_inode->di_gid));
 302        set_nlink(inode, le16_to_cpu(raw_inode->di_nlink));
 303        inode->i_size    = le32_to_cpu(raw_inode->di_size);
 304        inode->i_mtime.tv_sec   = le32_to_cpu(raw_inode->di_mtime);
 305        inode->i_mtime.tv_nsec = 0;
 306        inode->i_atime.tv_sec   = le32_to_cpu(raw_inode->di_atime);
 307        inode->i_atime.tv_nsec = 0;
 308        inode->i_ctime.tv_sec   = le32_to_cpu(raw_inode->di_ctime);
 309        inode->i_ctime.tv_nsec = 0;
 310        inode->i_blocks  = le32_to_cpu(raw_inode->di_first_xtnt.xtnt_size);
 311
 312        memcpy(qnx4_inode, raw_inode, QNX4_DIR_ENTRY_SIZE);
 313        if (S_ISREG(inode->i_mode)) {
 314                inode->i_fop = &generic_ro_fops;
 315                inode->i_mapping->a_ops = &qnx4_aops;
 316                qnx4_i(inode)->mmu_private = inode->i_size;
 317        } else if (S_ISDIR(inode->i_mode)) {
 318                inode->i_op = &qnx4_dir_inode_operations;
 319                inode->i_fop = &qnx4_dir_operations;
 320        } else if (S_ISLNK(inode->i_mode)) {
 321                inode->i_op = &page_symlink_inode_operations;
 322                inode_nohighmem(inode);
 323                inode->i_mapping->a_ops = &qnx4_aops;
 324                qnx4_i(inode)->mmu_private = inode->i_size;
 325        } else {
 326                printk(KERN_ERR "qnx4: bad inode %lu on dev %s\n",
 327                        ino, sb->s_id);
 328                iget_failed(inode);
 329                brelse(bh);
 330                return ERR_PTR(-EIO);
 331        }
 332        brelse(bh);
 333        unlock_new_inode(inode);
 334        return inode;
 335}
 336
 337static struct kmem_cache *qnx4_inode_cachep;
 338
 339static struct inode *qnx4_alloc_inode(struct super_block *sb)
 340{
 341        struct qnx4_inode_info *ei;
 342        ei = kmem_cache_alloc(qnx4_inode_cachep, GFP_KERNEL);
 343        if (!ei)
 344                return NULL;
 345        return &ei->vfs_inode;
 346}
 347
 348static void qnx4_free_inode(struct inode *inode)
 349{
 350        kmem_cache_free(qnx4_inode_cachep, qnx4_i(inode));
 351}
 352
 353static void init_once(void *foo)
 354{
 355        struct qnx4_inode_info *ei = (struct qnx4_inode_info *) foo;
 356
 357        inode_init_once(&ei->vfs_inode);
 358}
 359
 360static int init_inodecache(void)
 361{
 362        qnx4_inode_cachep = kmem_cache_create("qnx4_inode_cache",
 363                                             sizeof(struct qnx4_inode_info),
 364                                             0, (SLAB_RECLAIM_ACCOUNT|
 365                                                SLAB_MEM_SPREAD|SLAB_ACCOUNT),
 366                                             init_once);
 367        if (qnx4_inode_cachep == NULL)
 368                return -ENOMEM;
 369        return 0;
 370}
 371
 372static void destroy_inodecache(void)
 373{
 374        /*
 375         * Make sure all delayed rcu free inodes are flushed before we
 376         * destroy cache.
 377         */
 378        rcu_barrier();
 379        kmem_cache_destroy(qnx4_inode_cachep);
 380}
 381
 382static struct dentry *qnx4_mount(struct file_system_type *fs_type,
 383        int flags, const char *dev_name, void *data)
 384{
 385        return mount_bdev(fs_type, flags, dev_name, data, qnx4_fill_super);
 386}
 387
 388static struct file_system_type qnx4_fs_type = {
 389        .owner          = THIS_MODULE,
 390        .name           = "qnx4",
 391        .mount          = qnx4_mount,
 392        .kill_sb        = qnx4_kill_sb,
 393        .fs_flags       = FS_REQUIRES_DEV,
 394};
 395MODULE_ALIAS_FS("qnx4");
 396
 397static int __init init_qnx4_fs(void)
 398{
 399        int err;
 400
 401        err = init_inodecache();
 402        if (err)
 403                return err;
 404
 405        err = register_filesystem(&qnx4_fs_type);
 406        if (err) {
 407                destroy_inodecache();
 408                return err;
 409        }
 410
 411        printk(KERN_INFO "QNX4 filesystem 0.2.3 registered.\n");
 412        return 0;
 413}
 414
 415static void __exit exit_qnx4_fs(void)
 416{
 417        unregister_filesystem(&qnx4_fs_type);
 418        destroy_inodecache();
 419}
 420
 421module_init(init_qnx4_fs)
 422module_exit(exit_qnx4_fs)
 423MODULE_LICENSE("GPL");
 424
 425