dir.c

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/*
 *  linux/fs/adfs/dir.c
 *
 *  Copyright (C) 1999-2000 Russell King
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 *  Common directory handling for ADFS
 */
#include "adfs.h"

/*
 * For future.  This should probably be per-directory.
 */
static DEFINE_RWLOCK(adfs_dir_lock);

static int
adfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
{
    struct inode *inode = filp->f_path.dentry->d_inode;
    struct super_block *sb = inode->i_sb;
    struct adfs_dir_ops *ops = ADFS_SB(sb)->s_dir;
    struct object_info obj;
    struct adfs_dir dir;
    int ret = 0;

    if (filp->f_pos >> 32)
        goto out;

    ret = ops->read(sb, inode->i_ino, inode->i_size, &dir);
    if (ret)
        goto out;

    switch ((unsigned long)filp->f_pos) {
    case 0:
        if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR) < 0)
            goto free_out;
        filp->f_pos += 1;

    case 1:
        if (filldir(dirent, "..", 2, 1, dir.parent_id, DT_DIR) < 0)
            goto free_out;
        filp->f_pos += 1;

    default:
        break;
    }

    read_lock(&adfs_dir_lock);

    ret = ops->setpos(&dir, filp->f_pos - 2);
    if (ret)
        goto unlock_out;
    while (ops->getnext(&dir, &obj) == 0) {
        if (filldir(dirent, obj.name, obj.name_len,
                filp->f_pos, obj.file_id, DT_UNKNOWN) < 0)
            goto unlock_out;
        filp->f_pos += 1;
    }

unlock_out:
    read_unlock(&adfs_dir_lock);

free_out:
    ops->free(&dir);

out:
    return ret;
}

int
adfs_dir_update(struct super_block *sb, struct object_info *obj, int wait)
{
    int ret = -EINVAL;
#ifdef CONFIG_ADFS_FS_RW
    struct adfs_dir_ops *ops = ADFS_SB(sb)->s_dir;
    struct adfs_dir dir;

    printk(KERN_INFO "adfs_dir_update: object %06X in dir %06X\n",
         obj->file_id, obj->parent_id);

    if (!ops->update) {
        ret = -EINVAL;
        goto out;
    }

    ret = ops->read(sb, obj->parent_id, 0, &dir);
    if (ret)
        goto out;

    write_lock(&adfs_dir_lock);
    ret = ops->update(&dir, obj);
    write_unlock(&adfs_dir_lock);

    if (wait) {
        int err = ops->sync(&dir);
        if (!ret)
            ret = err;
    }

    ops->free(&dir);
out:
#endif
    return ret;
}

static int
adfs_match(struct qstr *name, struct object_info *obj)
{
    int i;

    if (name->len != obj->name_len)
        return 0;

    for (i = 0; i < name->len; i++) {
        char c1, c2;

        c1 = name->name[i];
        c2 = obj->name[i];

        if (c1 >= 'A' && c1 <= 'Z')
            c1 += 'a' - 'A';
        if (c2 >= 'A' && c2 <= 'Z')
            c2 += 'a' - 'A';

        if (c1 != c2)
            return 0;
    }
    return 1;
}

static int
adfs_dir_lookup_byname(struct inode *inode, struct qstr *name, struct object_info *obj)
{
    struct super_block *sb = inode->i_sb;
    struct adfs_dir_ops *ops = ADFS_SB(sb)->s_dir;
    struct adfs_dir dir;
    int ret;

    ret = ops->read(sb, inode->i_ino, inode->i_size, &dir);
    if (ret)
        goto out;

    if (ADFS_I(inode)->parent_id != dir.parent_id) {
        adfs_error(sb, "parent directory changed under me! (%lx but got %lx)\n",
               ADFS_I(inode)->parent_id, dir.parent_id);
        ret = -EIO;
        goto free_out;
    }

    obj->parent_id = inode->i_ino;

    /*
     * '.' is handled by reserved_lookup() in fs/namei.c
     */
    if (name->len == 2 && name->name[0] == '.' && name->name[1] == '.') {
        /*
         * Currently unable to fill in the rest of 'obj',
         * but this is better than nothing.  We need to
         * ascend one level to find it's parent.
         */
        obj->name_len = 0;
        obj->file_id  = obj->parent_id;
        goto free_out;
    }

    read_lock(&adfs_dir_lock);

    ret = ops->setpos(&dir, 0);
    if (ret)
        goto unlock_out;

    ret = -ENOENT;
    while (ops->getnext(&dir, obj) == 0) {
        if (adfs_match(name, obj)) {
            ret = 0;
            break;
        }
    }

unlock_out:
    read_unlock(&adfs_dir_lock);

free_out:
    ops->free(&dir);
out:
    return ret;
}

const struct file_operations adfs_dir_operations = {
    .read       = generic_read_dir,
    .llseek     = generic_file_llseek,
    .readdir    = adfs_readdir,
    .fsync      = generic_file_fsync,
};

static int
adfs_hash(const struct dentry *parent, const struct inode *inode,
        struct qstr *qstr)
{
    const unsigned int name_len = ADFS_SB(parent->d_sb)->s_namelen;
    const unsigned char *name;
    unsigned long hash;
    int i;

    if (qstr->len < name_len)
        return 0;

    /*
     * Truncate the name in place, avoids
     * having to define a compare function.
     */
    qstr->len = i = name_len;
    name = qstr->name;
    hash = init_name_hash();
    while (i--) {
        char c;

        c = *name++;
        if (c >= 'A' && c <= 'Z')
            c += 'a' - 'A';

        hash = partial_name_hash(c, hash);
    }
    qstr->hash = end_name_hash(hash);

    return 0;
}

/*
 * Compare two names, taking note of the name length
 * requirements of the underlying filesystem.
 */
static int
adfs_compare(const struct dentry *parent, const struct inode *pinode,
        const struct dentry *dentry, const struct inode *inode,
        unsigned int len, const char *str, const struct qstr *name)
{
    int i;

    if (len != name->len)
        return 1;

    for (i = 0; i < name->len; i++) {
        char a, b;

        a = str[i];
        b = name->name[i];

        if (a >= 'A' && a <= 'Z')
            a += 'a' - 'A';
        if (b >= 'A' && b <= 'Z')
            b += 'a' - 'A';

        if (a != b)
            return 1;
    }
    return 0;
}

const struct dentry_operations adfs_dentry_operations = {
    .d_hash     = adfs_hash,
    .d_compare  = adfs_compare,
};

static struct dentry *
adfs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
{
    struct inode *inode = NULL;
    struct object_info obj;
    int error;

    error = adfs_dir_lookup_byname(dir, &dentry->d_name, &obj);
    if (error == 0) {
        error = -EACCES;
        /*
         * This only returns NULL if get_empty_inode
         * fails.
         */
        inode = adfs_iget(dir->i_sb, &obj);
        if (inode)
            error = 0;
    }
    d_add(dentry, inode);
    return ERR_PTR(error);
}

/*
 * directories can handle most operations...
 */
const struct inode_operations adfs_dir_inode_operations = {
    .lookup     = adfs_lookup,
    .setattr    = adfs_notify_change,
};