linux-imx

/*

 * Copyright (C) 2011 Novell Inc.

 * Copyright (C) 2016 Red Hat, Inc.

 *

 * 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.

 */

​

#include <linux/fs.h>

#include <linux/mount.h>

#include <linux/slab.h>

#include <linux/cred.h>

#include <linux/xattr.h>

#include <linux/exportfs.h>

#include <linux/uuid.h>

#include <linux/namei.h>

#include <linux/ratelimit.h>

#include "overlayfs.h"

​

int ovl_want_write(struct dentry *dentry)

{

    struct ovl_fs *ofs = dentry->d_sb->s_fs_info;

    return mnt_want_write(ofs->upper_mnt);

}

​

void ovl_drop_write(struct dentry *dentry)

{

    struct ovl_fs *ofs = dentry->d_sb->s_fs_info;

    mnt_drop_write(ofs->upper_mnt);

}

​

struct dentry *ovl_workdir(struct dentry *dentry)

{

    struct ovl_fs *ofs = dentry->d_sb->s_fs_info;

    return ofs->workdir;

}

​

const struct cred *ovl_override_creds(struct super_block *sb)

{

    struct ovl_fs *ofs = sb->s_fs_info;

​

    return override_creds(ofs->creator_cred);

}

​

struct super_block *ovl_same_sb(struct super_block *sb)

{

    struct ovl_fs *ofs = sb->s_fs_info;

​

    if (!ofs->numlowerfs)

        return ofs->upper_mnt->mnt_sb;

    else if (ofs->numlowerfs == 1 && !ofs->upper_mnt)

        return ofs->lower_fs[0].sb;

    else

        return NULL;

}

​

/*

 * Check if underlying fs supports file handles and try to determine encoding

 * type, in order to deduce maximum inode number used by fs.

 *

 * Return 0 if file handles are not supported.

 * Return 1 (FILEID_INO32_GEN) if fs uses the default 32bit inode encoding.

 * Return -1 if fs uses a non default encoding with unknown inode size.

 */

int ovl_can_decode_fh(struct super_block *sb)

{

    if (!sb->s_export_op || !sb->s_export_op->fh_to_dentry)

        return 0;

​

    return sb->s_export_op->encode_fh ? -1 : FILEID_INO32_GEN;

}

​

struct dentry *ovl_indexdir(struct super_block *sb)

{

    struct ovl_fs *ofs = sb->s_fs_info;

​

    return ofs->indexdir;

}

​

/* Index all files on copy up. For now only enabled for NFS export */

bool ovl_index_all(struct super_block *sb)

{

    struct ovl_fs *ofs = sb->s_fs_info;

​

    return ofs->config.nfs_export && ofs->config.index;

}

​

/* Verify lower origin on lookup. For now only enabled for NFS export */

bool ovl_verify_lower(struct super_block *sb)

{

    struct ovl_fs *ofs = sb->s_fs_info;