Fixed MTP to work with TWRP

fs/adfs/dir.c

@@ -0,0 +1,288 @@
+/*
+ *  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 *file, struct dir_context *ctx)
+{
+	struct inode *inode = file_inode(file);
+	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 (ctx->pos >> 32)
+		return 0;
+
+	ret = ops->read(sb, inode->i_ino, inode->i_size, &dir);
+	if (ret)
+		return ret;
+
+	if (ctx->pos == 0) {
+		if (!dir_emit_dot(file, ctx))
+			goto free_out;
+		ctx->pos = 1;
+	}
+	if (ctx->pos == 1) {
+		if (!dir_emit(ctx, "..", 2, dir.parent_id, DT_DIR))
+			goto free_out;
+		ctx->pos = 2;
+	}
+
+	read_lock(&adfs_dir_lock);
+
+	ret = ops->setpos(&dir, ctx->pos - 2);
+	if (ret)
+		goto unlock_out;
+	while (ops->getnext(&dir, &obj) == 0) {
+		if (!dir_emit(ctx, obj.name, obj.name_len,
+			    obj.file_id, DT_UNKNOWN))
+			break;
+		ctx->pos++;
+	}
+
+unlock_out:
+	read_unlock(&adfs_dir_lock);
+
+free_out:
+	ops->free(&dir);
+	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 %x)\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,
+	.iterate	= adfs_readdir,
+	.fsync		= generic_file_fsync,
+};
+
+static int
+adfs_hash(const struct dentry *parent, 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 dentry *dentry,
+		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,
+};