/*
 *  linux/fs/9p/vfs_super.c
 *
 * This file contians superblock ops for 9P2000. It is intended that
 * you mount this file system on directories.
 *
 *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
 *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
 *
 *  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.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to:
 *  Free Software Foundation
 *  51 Franklin Street, Fifth Floor
 *  Boston, MA  02111-1301  USA
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <linux/inet.h>
#include <linux/pagemap.h>
#include <linux/seq_file.h>
#include <linux/mount.h>
#include <linux/idr.h>
#include <linux/sched.h>
#include <net/9p/9p.h>
#include <net/9p/client.h>

#include "v9fs.h"
#include "v9fs_vfs.h"
#include "fid.h"

static void v9fs_clear_inode(struct inode *);
static const struct super_operations v9fs_super_ops;

/**
 * v9fs_clear_inode - release an inode
 * @inode: inode to release
 *
 */

static void v9fs_clear_inode(struct inode *inode)
{
        filemap_fdatawrite(inode->i_mapping);
}

/**
 * v9fs_set_super - set the superblock
 * @s: super block
 * @data: file system specific data
 *
 */

static int v9fs_set_super(struct super_block *s, void *data)
{
        s->s_fs_info = data;
        return set_anon_super(s, data);
}

/**
 * v9fs_fill_super - populate superblock with info
 * @sb: superblock
 * @v9ses: session information
 *
 */

static void
v9fs_fill_super(struct super_block *sb, struct v9fs_session_info *v9ses,
                int flags)
{
        sb->s_maxbytes = MAX_LFS_FILESIZE;
        sb->s_blocksize_bits = fls(v9ses->maxdata - 1);
        sb->s_blocksize = 1 << sb->s_blocksize_bits;
        sb->s_magic = V9FS_MAGIC;
        sb->s_op = &v9fs_super_ops;

        sb->s_flags = flags | MS_ACTIVE | MS_SYNCHRONOUS | MS_DIRSYNC |
            MS_NOATIME;
}

/**
 * v9fs_get_sb - mount a superblock
 * @fs_type: file system type
 * @flags: mount flags
 * @dev_name: device name that was mounted
 * @data: mount options
 * @mnt: mountpoint record to be instantiated
 *
 */

static int v9fs_get_sb(struct file_system_type *fs_type, int flags,
                       const char *dev_name, void *data,
                       struct vfsmount *mnt)
{
        struct super_block *sb = NULL;
        struct inode *inode = NULL;
        struct dentry *root = NULL;
        struct v9fs_session_info *v9ses = NULL;
        struct p9_stat *st = NULL;
        int mode = S_IRWXUGO | S_ISVTX;
        uid_t uid = current->fsuid;
        gid_t gid = current->fsgid;
        struct p9_fid *fid;
        int retval = 0;

        P9_DPRINTK(P9_DEBUG_VFS, " \n");

        st = NULL;
        v9ses = kzalloc(sizeof(struct v9fs_session_info), GFP_KERNEL);
        if (!v9ses)
                return -ENOMEM;

        fid = v9fs_session_init(v9ses, dev_name, data);
        if (IS_ERR(fid)) {
                retval = PTR_ERR(fid);
                fid = NULL;
                kfree(v9ses);
                v9ses = NULL;
                goto error;
        }

        st = p9_client_stat(fid);
        if (IS_ERR(st)) {
                retval = PTR_ERR(st);
                goto error;
        }

        sb = sget(fs_type, NULL, v9fs_set_super, v9ses);
        if (IS_ERR(sb)) {
                retval = PTR_ERR(sb);
                goto error;
        }
        v9fs_fill_super(sb, v9ses, flags);

        inode = v9fs_get_inode(sb, S_IFDIR | mode);
        if (IS_ERR(inode)) {
                retval = PTR_ERR(inode);
                goto error;
        }

        inode->i_uid = uid;
        inode->i_gid = gid;

        root = d_alloc_root(inode);
        if (!root) {
                retval = -ENOMEM;
                goto error;
        }

        sb->s_root = root;
        root->d_inode->i_ino = v9fs_qid2ino(&st->qid);
        v9fs_stat2inode(st, root->d_inode, sb);
        v9fs_fid_add(root, fid);
        kfree(st);

        return simple_set_mnt(mnt, sb);

error:
        kfree(st);
        if (fid)
                p9_client_clunk(fid);

        if (v9ses) {
                v9fs_session_close(v9ses);
                kfree(v9ses);
        }

        if (sb) {
                up_write(&sb->s_umount);
                deactivate_super(sb);
        }

        return retval;
}

/**
 * v9fs_kill_super - Kill Superblock
 * @s: superblock
 *
 */

static void v9fs_kill_super(struct super_block *s)
{
        struct v9fs_session_info *v9ses = s->s_fs_info;

        P9_DPRINTK(P9_DEBUG_VFS, " %p\n", s);

        v9fs_dentry_release(s->s_root); /* clunk root */

        kill_anon_super(s);

        v9fs_session_close(v9ses);
        kfree(v9ses);
        P9_DPRINTK(P9_DEBUG_VFS, "exiting kill_super\n");
}

/**
 * v9fs_show_options - Show mount options in /proc/mounts
 * @m: seq_file to write to
 * @mnt: mount descriptor
 *
 */

static int v9fs_show_options(struct seq_file *m, struct vfsmount *mnt)
{
        struct v9fs_session_info *v9ses = mnt->mnt_sb->s_fs_info;

        seq_printf(m, "%s", v9ses->options);
        return 0;
}

static void
v9fs_umount_begin(struct vfsmount *vfsmnt, int flags)
{
        struct v9fs_session_info *v9ses = vfsmnt->mnt_sb->s_fs_info;

        if (flags & MNT_FORCE)
                v9fs_session_cancel(v9ses);
}

static const struct super_operations v9fs_super_ops = {
        .statfs = simple_statfs,
        .clear_inode = v9fs_clear_inode,
        .show_options = v9fs_show_options,
        .umount_begin = v9fs_umount_begin,
};

struct file_system_type v9fs_fs_type = {
        .name = "9p",
        .get_sb = v9fs_get_sb,
        .kill_sb = v9fs_kill_super,
        .owner = THIS_MODULE,
};