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/*

 * QNX4 file system, Linux implementation.

 *

 * Version : 0.2.1

 *

 * Using parts of the xiafs filesystem.

 *

 * History :

 *

 * 01-06-1998 by Richard Frowijn : first release.

 * 20-06-1998 by Frank Denis : Linux 2.1.99+ support, boot signature, misc.

 * 30-06-1998 by Frank Denis : first step to write inodes.

 */

#include <linux/module.h>

#include <linux/types.h>

#include <linux/string.h>

#include <linux/errno.h>

#include <linux/slab.h>

#include <linux/fs.h>

#include <linux/qnx4_fs.h>

#include <linux/init.h>

#include <linux/highuid.h>

#include <linux/smp_lock.h>

#include <linux/pagemap.h>

#include <linux/buffer_head.h>

#include <linux/vfs.h>

#include <asm/uaccess.h>

#define QNX4_VERSION  4

#define QNX4_BMNAME   ".bitmap"

static const struct super_operations qnx4_sops;

#ifdef CONFIG_QNX4FS_RW

int qnx4_sync_inode(struct inode *inode)

{

        int err = 0;

# if 0

        struct buffer_head *bh;

        bh = qnx4_update_inode(inode);

        if (bh && buffer_dirty(bh))

        {

                sync_dirty_buffer(bh);

                if (buffer_req(bh) && !buffer_uptodate(bh))

                {

                        printk ("IO error syncing qnx4 inode [%s:%08lx]\n",

                                inode->i_sb->s_id, inode->i_ino);

                        err = -1;

                }

                brelse (bh);

        } else if (!bh) {

                err = -1;

        }

# endif

        return err;

}

static void qnx4_delete_inode(struct inode *inode)

{

        QNX4DEBUG(("qnx4: deleting inode [%lu]\n", (unsigned long) inode->i_ino));

        truncate_inode_pages(&inode->i_data, 0);

        inode->i_size = 0;

        qnx4_truncate(inode);

        lock_kernel();

        qnx4_free_inode(inode);

        unlock_kernel();

}

static void qnx4_write_super(struct super_block *sb)

{

        lock_kernel();

        QNX4DEBUG(("qnx4: write_super\n"));

        sb->s_dirt = 0;

        unlock_kernel();

}

static int qnx4_write_inode(struct inode *inode, int unused)

{

        struct qnx4_inode_entry *raw_inode;

        int block, ino;

        struct buffer_head *bh;

        ino = inode->i_ino;

        QNX4DEBUG(("qnx4: write inode 1.\n"));

        if (inode->i_nlink == 0) {

                return 0;

        }

        if (!ino) {

                printk("qnx4: bad inode number on dev %s: %d is out of range\n",

                       inode->i_sb->s_id, ino);

                return -EIO;

        }

        QNX4DEBUG(("qnx4: write inode 2.\n"));

        block = ino / QNX4_INODES_PER_BLOCK;

        lock_kernel();

        if (!(bh = sb_bread(inode->i_sb, block))) {

                printk("qnx4: major problem: unable to read inode from dev "

                       "%s\n", inode->i_sb->s_id);

                unlock_kernel();

                return -EIO;

        }

        raw_inode = ((struct qnx4_inode_entry *) bh->b_data) +

            (ino % QNX4_INODES_PER_BLOCK);

        raw_inode->di_mode  = cpu_to_le16(inode->i_mode);

        raw_inode->di_uid   = cpu_to_le16(fs_high2lowuid(inode->i_uid));

        raw_inode->di_gid   = cpu_to_le16(fs_high2lowgid(inode->i_gid));

        raw_inode->di_nlink = cpu_to_le16(inode->i_nlink);

        raw_inode->di_size  = cpu_to_le32(inode->i_size);

        raw_inode->di_mtime = cpu_to_le32(inode->i_mtime.tv_sec);

        raw_inode->di_atime = cpu_to_le32(inode->i_atime.tv_sec);

        raw_inode->di_ctime = cpu_to_le32(inode->i_ctime.tv_sec);

        raw_inode->di_first_xtnt.xtnt_size = cpu_to_le32(inode->i_blocks);

        mark_buffer_dirty(bh);

        brelse(bh);

        unlock_kernel();

        return 0;

}

#endif

static void qnx4_put_super(struct super_block *sb);

static struct inode *qnx4_alloc_inode(struct super_block *sb);

static void qnx4_destroy_inode(struct inode *inode);

static void qnx4_read_inode(struct inode *);

static int qnx4_remount(struct super_block *sb, int *flags, char *data);

static int qnx4_statfs(struct dentry *, struct kstatfs *);

static const struct super_operations qnx4_sops =

{

        .alloc_inode    = qnx4_alloc_inode,

        .destroy_inode  = qnx4_destroy_inode,

        .read_inode     = qnx4_read_inode,

        .put_super      = qnx4_put_super,

        .statfs         = qnx4_statfs,

        .remount_fs     = qnx4_remount,

#ifdef CONFIG_QNX4FS_RW

        .write_inode    = qnx4_write_inode,

        .delete_inode   = qnx4_delete_inode,

        .write_super    = qnx4_write_super,

#endif

};

static int qnx4_remount(struct super_block *sb, int *flags, char *data)

{

        struct qnx4_sb_info *qs;

        qs = qnx4_sb(sb);

        qs->Version = QNX4_VERSION;

#ifndef CONFIG_QNX4FS_RW

        *flags |= MS_RDONLY;

#endif

        if (*flags & MS_RDONLY) {

                return 0;

        }

        mark_buffer_dirty(qs->sb_buf);

        return 0;

}

static struct buffer_head *qnx4_getblk(struct inode *inode, int nr,

                                       int create)

{

        struct buffer_head *result = NULL;

        if ( nr >= 0 )

                nr = qnx4_block_map( inode, nr );

        if (nr) {

                result = sb_getblk(inode->i_sb, nr);

                return result;

        }

        if (!create) {

                return NULL;

        }

#if 0

        tmp = qnx4_new_block(inode->i_sb);

        if (!tmp) {

                return NULL;

        }

        result = sb_getblk(inode->i_sb, tmp);

        if (tst) {

                qnx4_free_block(inode->i_sb, tmp);

                brelse(result);

                goto repeat;

        }

        tst = tmp;

#endif

        inode->i_ctime = CURRENT_TIME_SEC;

        mark_inode_dirty(inode);

        return result;

}

struct buffer_head *qnx4_bread(struct inode *inode, int block, int create)

{

        struct buffer_head *bh;

        bh = qnx4_getblk(inode, block, create);

        if (!bh || buffer_uptodate(bh)) {

                return bh;

        }

        ll_rw_block(READ, 1, &bh);

        wait_on_buffer(bh);

        if (buffer_uptodate(bh)) {

                return bh;

        }

        brelse(bh);

        return NULL;

}

static int qnx4_get_block( struct inode *inode, sector_t iblock, struct buffer_head *bh, int create )

{

        unsigned long phys;

        QNX4DEBUG(("qnx4: qnx4_get_block inode=[%ld] iblock=[%ld]\n",inode->i_ino,iblock));

        phys = qnx4_block_map( inode, iblock );

        if ( phys ) {

                // logical block is before EOF

                map_bh(bh, inode->i_sb, phys);

        } else if ( create ) {

                // to be done.

        }

        return 0;

}

unsigned long qnx4_block_map( struct inode *inode, long iblock )

{

        int ix;

        long offset, i_xblk;

        unsigned long block = 0;

        struct buffer_head *bh = NULL;

        struct qnx4_xblk *xblk = NULL;

        struct qnx4_inode_entry *qnx4_inode = qnx4_raw_inode(inode);

        u16 nxtnt = le16_to_cpu(qnx4_inode->di_num_xtnts);

        if ( iblock < le32_to_cpu(qnx4_inode->di_first_xtnt.xtnt_size) ) {

                // iblock is in the first extent. This is easy.

                block = le32_to_cpu(qnx4_inode->di_first_xtnt.xtnt_blk) + iblock - 1;

        } else {

                // iblock is beyond first extent. We have to follow the extent chain.

                i_xblk = le32_to_cpu(qnx4_inode->di_xblk);

                offset = iblock - le32_to_cpu(qnx4_inode->di_first_xtnt.xtnt_size);

                ix = 0;

                while ( --nxtnt > 0 ) {

                        if ( ix == 0 ) {

                                // read next xtnt block.

                                bh = sb_bread(inode->i_sb, i_xblk - 1);

                                if ( !bh ) {

                                        QNX4DEBUG(("qnx4: I/O error reading xtnt block [%ld])\n", i_xblk - 1));

                                        return -EIO;

                                }

                                xblk = (struct qnx4_xblk*)bh->b_data;

                                if ( memcmp( xblk->xblk_signature, "IamXblk", 7 ) ) {

                                        QNX4DEBUG(("qnx4: block at %ld is not a valid xtnt\n", qnx4_inode->i_xblk));

                                        return -EIO;

                                }

                        }

                        if ( offset < le32_to_cpu(xblk->xblk_xtnts[ix].xtnt_size) ) {

                                // got it!

                                block = le32_to_cpu(xblk->xblk_xtnts[ix].xtnt_blk) + offset - 1;

                                break;

                        }

                        offset -= le32_to_cpu(xblk->xblk_xtnts[ix].xtnt_size);

                        if ( ++ix >= xblk->xblk_num_xtnts ) {

                                i_xblk = le32_to_cpu(xblk->xblk_next_xblk);

                                ix = 0;

                                brelse( bh );

                                bh = NULL;

                        }

                }

                if ( bh )

                        brelse( bh );

        }

        QNX4DEBUG(("qnx4: mapping block %ld of inode %ld = %ld\n",iblock,inode->i_ino,block));

        return block;

}

static int qnx4_statfs(struct dentry *dentry, struct kstatfs *buf)

{

        struct super_block *sb = dentry->d_sb;

        lock_kernel();

        buf->f_type    = sb->s_magic;

        buf->f_bsize   = sb->s_blocksize;

        buf->f_blocks  = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size) * 8;

        buf->f_bfree   = qnx4_count_free_blocks(sb);

        buf->f_bavail  = buf->f_bfree;

        buf->f_namelen = QNX4_NAME_MAX;

        unlock_kernel();

        return 0;

}

/*

 * Check the root directory of the filesystem to make sure

 * it really _is_ a qnx4 filesystem, and to check the size

 * of the directory entry.

 */

static const char *qnx4_checkroot(struct super_block *sb)

{

        struct buffer_head *bh;

        struct qnx4_inode_entry *rootdir;

        int rd, rl;

        int i, j;

        int found = 0;

        if (*(qnx4_sb(sb)->sb->RootDir.di_fname) != '/') {

                return "no qnx4 filesystem (no root dir).";

        } else {

                QNX4DEBUG(("QNX4 filesystem found on dev %s.\n", sb->s_id));

                rd = le32_to_cpu(qnx4_sb(sb)->sb->RootDir.di_first_xtnt.xtnt_blk) - 1;

                rl = le32_to_cpu(qnx4_sb(sb)->sb->RootDir.di_first_xtnt.xtnt_size);

                for (j = 0; j < rl; j++) {

                        bh = sb_bread(sb, rd + j);      /* root dir, first block */

                        if (bh == NULL) {

                                return "unable to read root entry.";

                        }

                        for (i = 0; i < QNX4_INODES_PER_BLOCK; i++) {

                                rootdir = (struct qnx4_inode_entry *) (bh->b_data + i * QNX4_DIR_ENTRY_SIZE);

                                if (rootdir->di_fname != NULL) {

                                        QNX4DEBUG(("Rootdir entry found : [%s]\n", rootdir->di_fname));

                                        if (!strncmp(rootdir->di_fname, QNX4_BMNAME, sizeof QNX4_BMNAME)) {

                                                found = 1;

                                                qnx4_sb(sb)->BitMap = kmalloc( sizeof( struct qnx4_inode_entry ), GFP_KERNEL );

                                                if (!qnx4_sb(sb)->BitMap) {

                                                        brelse (bh);

                                                        return "not enough memory for bitmap inode";

                                                }

                                                memcpy( qnx4_sb(sb)->BitMap, rootdir, sizeof( struct qnx4_inode_entry ) );      /* keep bitmap inode known */

                                                break;

                                        }

                                }

                        }

                        brelse(bh);

                        if (found != 0) {

                                break;

                        }

                }

                if (found == 0) {

                        return "bitmap file not found.";

                }

        }

        return NULL;

}

static int qnx4_fill_super(struct super_block *s, void *data, int silent)

{

        struct buffer_head *bh;

        struct inode *root;

        const char *errmsg;

        struct qnx4_sb_info *qs;

        qs = kzalloc(sizeof(struct qnx4_sb_info), GFP_KERNEL);

        if (!qs)

                return -ENOMEM;

        s->s_fs_info = qs;

        sb_set_blocksize(s, QNX4_BLOCK_SIZE);

        /* Check the superblock signature. Since the qnx4 code is

           dangerous, we should leave as quickly as possible

           if we don't belong here... */

        bh = sb_bread(s, 1);

        if (!bh) {

                printk("qnx4: unable to read the superblock\n");

                goto outnobh;

        }

        if ( le32_to_cpup((__le32*) bh->b_data) != QNX4_SUPER_MAGIC ) {

                if (!silent)

                        printk("qnx4: wrong fsid in superblock.\n");

                goto out;

        }

        s->s_op = &qnx4_sops;

        s->s_magic = QNX4_SUPER_MAGIC;

#ifndef CONFIG_QNX4FS_RW

        s->s_flags |= MS_RDONLY;        /* Yup, read-only yet */

#endif

        qnx4_sb(s)->sb_buf = bh;

        qnx4_sb(s)->sb = (struct qnx4_super_block *) bh->b_data;

        /* check before allocating dentries, inodes, .. */

        errmsg = qnx4_checkroot(s);

        if (errmsg != NULL) {

                if (!silent)

                        printk("qnx4: %s\n", errmsg);

                goto out;

        }

        /* does root not have inode number QNX4_ROOT_INO ?? */

        root = iget(s, QNX4_ROOT_INO * QNX4_INODES_PER_BLOCK);

        if (!root) {

                printk("qnx4: get inode failed\n");

                goto out;

        }

        s->s_root = d_alloc_root(root);

        if (s->s_root == NULL)

                goto outi;

        brelse(bh);

        return 0;

      outi:

        iput(root);

      out:

        brelse(bh);

      outnobh:

        kfree(qs);

        s->s_fs_info = NULL;

        return -EINVAL;

}

static void qnx4_put_super(struct super_block *sb)

{

        struct qnx4_sb_info *qs = qnx4_sb(sb);

        kfree( qs->BitMap );

        kfree( qs );

        sb->s_fs_info = NULL;

        return;

}

static int qnx4_writepage(struct page *page, struct writeback_control *wbc)

{

        return block_write_full_page(page,qnx4_get_block, wbc);

}

static int qnx4_readpage(struct file *file, struct page *page)

{

        return block_read_full_page(page,qnx4_get_block);

}

static int qnx4_write_begin(struct file *file, struct address_space *mapping,

                        loff_t pos, unsigned len, unsigned flags,

                        struct page **pagep, void **fsdata)

{

        struct qnx4_inode_info *qnx4_inode = qnx4_i(mapping->host);

        *pagep = NULL;

        return cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,

                                qnx4_get_block,

                                &qnx4_inode->mmu_private);

}

static sector_t qnx4_bmap(struct address_space *mapping, sector_t block)

{

        return generic_block_bmap(mapping,block,qnx4_get_block);

}

static const struct address_space_operations qnx4_aops = {

        .readpage       = qnx4_readpage,

        .writepage      = qnx4_writepage,

        .sync_page      = block_sync_page,

        .write_begin    = qnx4_write_begin,

        .write_end      = generic_write_end,

        .bmap           = qnx4_bmap

};

static void qnx4_read_inode(struct inode *inode)

{

        struct buffer_head *bh;

        struct qnx4_inode_entry *raw_inode;

        int block, ino;

        struct super_block *sb = inode->i_sb;

        struct qnx4_inode_entry *qnx4_inode = qnx4_raw_inode(inode);

        ino = inode->i_ino;

        inode->i_mode = 0;

        QNX4DEBUG(("Reading inode : [%d]\n", ino));

        if (!ino) {

                printk("qnx4: bad inode number on dev %s: %d is out of range\n",

                       sb->s_id, ino);

                return;

        }

        block = ino / QNX4_INODES_PER_BLOCK;

        if (!(bh = sb_bread(sb, block))) {

                printk("qnx4: major problem: unable to read inode from dev "

                       "%s\n", sb->s_id);

                return;

        }

        raw_inode = ((struct qnx4_inode_entry *) bh->b_data) +

            (ino % QNX4_INODES_PER_BLOCK);

        inode->i_mode    = le16_to_cpu(raw_inode->di_mode);

        inode->i_uid     = (uid_t)le16_to_cpu(raw_inode->di_uid);

        inode->i_gid     = (gid_t)le16_to_cpu(raw_inode->di_gid);

        inode->i_nlink   = le16_to_cpu(raw_inode->di_nlink);

        inode->i_size    = le32_to_cpu(raw_inode->di_size);

        inode->i_mtime.tv_sec   = le32_to_cpu(raw_inode->di_mtime);

        inode->i_mtime.tv_nsec = 0;

        inode->i_atime.tv_sec   = le32_to_cpu(raw_inode->di_atime);

        inode->i_atime.tv_nsec = 0;

        inode->i_ctime.tv_sec   = le32_to_cpu(raw_inode->di_ctime);

        inode->i_ctime.tv_nsec = 0;

        inode->i_blocks  = le32_to_cpu(raw_inode->di_first_xtnt.xtnt_size);

        memcpy(qnx4_inode, raw_inode, QNX4_DIR_ENTRY_SIZE);

        if (S_ISREG(inode->i_mode)) {

                inode->i_op = &qnx4_file_inode_operations;

                inode->i_fop = &qnx4_file_operations;

                inode->i_mapping->a_ops = &qnx4_aops;

                qnx4_i(inode)->mmu_private = inode->i_size;

        } else if (S_ISDIR(inode->i_mode)) {

                inode->i_op = &qnx4_dir_inode_operations;

                inode->i_fop = &qnx4_dir_operations;

        } else if (S_ISLNK(inode->i_mode)) {

                inode->i_op = &page_symlink_inode_operations;

                inode->i_mapping->a_ops = &qnx4_aops;

                qnx4_i(inode)->mmu_private = inode->i_size;

        } else

                printk("qnx4: bad inode %d on dev %s\n",ino,sb->s_id);

        brelse(bh);

}

static struct kmem_cache *qnx4_inode_cachep;

static struct inode *qnx4_alloc_inode(struct super_block *sb)

{

        struct qnx4_inode_info *ei;

        ei = kmem_cache_alloc(qnx4_inode_cachep, GFP_KERNEL);

        if (!ei)

                return NULL;

        return &ei->vfs_inode;

}

static void qnx4_destroy_inode(struct inode *inode)

{

        kmem_cache_free(qnx4_inode_cachep, qnx4_i(inode));

}

static void init_once(struct kmem_cache *cachep, void *foo)

{

        struct qnx4_inode_info *ei = (struct qnx4_inode_info *) foo;

        inode_init_once(&ei->vfs_inode);

}

static int init_inodecache(void)

{

        qnx4_inode_cachep = kmem_cache_create("qnx4_inode_cache",

                                             sizeof(struct qnx4_inode_info),

                                             0, (SLAB_RECLAIM_ACCOUNT|

                                                SLAB_MEM_SPREAD),

                                             init_once);

        if (qnx4_inode_cachep == NULL)

                return -ENOMEM;

        return 0;

}

static void destroy_inodecache(void)

{

        kmem_cache_destroy(qnx4_inode_cachep);

}

static int qnx4_get_sb(struct file_system_type *fs_type,

        int flags, const char *dev_name, void *data, struct vfsmount *mnt)

{

        return get_sb_bdev(fs_type, flags, dev_name, data, qnx4_fill_super,

                           mnt);

}

static struct file_system_type qnx4_fs_type = {

        .owner          = THIS_MODULE,

        .name           = "qnx4",

        .get_sb         = qnx4_get_sb,

        .kill_sb        = kill_block_super,

        .fs_flags       = FS_REQUIRES_DEV,

};

static int __init init_qnx4_fs(void)

{

        int err;

        err = init_inodecache();

        if (err)

                return err;

        err = register_filesystem(&qnx4_fs_type);

        if (err) {

                destroy_inodecache();

                return err;

        }

        printk("QNX4 filesystem 0.2.3 registered.\n");

        return 0;

}

static void __exit exit_qnx4_fs(void)

{

        unregister_filesystem(&qnx4_fs_type);

        destroy_inodecache();

}

module_init(init_qnx4_fs)

module_exit(exit_qnx4_fs)

MODULE_LICENSE("GPL");