LXR linux/fs/9p/vfs

   1/*
   2 *  linux/fs/9p/vfs_super.c
   3 *
   4 * This file contians superblock ops for 9P2000. It is intended that
   5 * you mount this file system on directories.
   6 *
   7 *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
   8 *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
   9 *
  10 *  This program is free software; you can redistribute it and/or modify
  11 *  it under the terms of the GNU General Public License version 2
  12 *  as published by the Free Software Foundation.
  13 *
  14 *  This program is distributed in the hope that it will be useful,
  15 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 *  GNU General Public License for more details.
  18 *
  19 *  You should have received a copy of the GNU General Public License
  20 *  along with this program; if not, write to:
  21 *  Free Software Foundation
  22 *  51 Franklin Street, Fifth Floor
  23 *  Boston, MA  02111-1301  USA
  24 *
  25 */
  26
  27#include <linux/kernel.h>
  28#include <linux/module.h>
  29#include <linux/errno.h>
  30#include <linux/fs.h>
  31#include <linux/file.h>
  32#include <linux/stat.h>
  33#include <linux/string.h>
  34#include <linux/inet.h>
  35#include <linux/pagemap.h>
  36#include <linux/seq_file.h>
  37#include <linux/mount.h>
  38#include <linux/idr.h>
  39#include <linux/sched.h>
  40#include <net/9p/9p.h>
  41#include <net/9p/client.h>
  42
  43#include "v9fs.h"
  44#include "v9fs_vfs.h"
  45#include "fid.h"
  46
  47static void v9fs_clear_inode(struct inode *);
  48static const struct super_operations v9fs_super_ops;
  49
  50/**
  51 * v9fs_clear_inode - release an inode
  52 * @inode: inode to release
  53 *
  54 */
  55
  56static void v9fs_clear_inode(struct inode *inode)
  57{
  58        filemap_fdatawrite(inode->i_mapping);
  59}
  60
  61/**
  62 * v9fs_set_super - set the superblock
  63 * @s: super block
  64 * @data: file system specific data
  65 *
  66 */
  67
  68static int v9fs_set_super(struct super_block *s, void *data)
  69{
  70        s->s_fs_info = data;
  71        return set_anon_super(s, data);
  72}
  73
  74/**
  75 * v9fs_fill_super - populate superblock with info
  76 * @sb: superblock
  77 * @v9ses: session information
  78 * @flags: flags propagated from v9fs_get_sb()
  79 *
  80 */
  81
  82static void
  83v9fs_fill_super(struct super_block *sb, struct v9fs_session_info *v9ses,
  84                int flags)
  85{
  86        sb->s_maxbytes = MAX_LFS_FILESIZE;
  87        sb->s_blocksize_bits = fls(v9ses->maxdata - 1);
  88        sb->s_blocksize = 1 << sb->s_blocksize_bits;
  89        sb->s_magic = V9FS_MAGIC;
  90        sb->s_op = &v9fs_super_ops;
  91
  92        sb->s_flags = flags | MS_ACTIVE | MS_SYNCHRONOUS | MS_DIRSYNC |
  93            MS_NOATIME;
  94}
  95
  96/**
  97 * v9fs_get_sb - mount a superblock
  98 * @fs_type: file system type
  99 * @flags: mount flags
 100 * @dev_name: device name that was mounted
 101 * @data: mount options
 102 * @mnt: mountpoint record to be instantiated
 103 *
 104 */
 105
 106static int v9fs_get_sb(struct file_system_type *fs_type, int flags,
 107                       const char *dev_name, void *data,
 108                       struct vfsmount *mnt)
 109{
 110        struct super_block *sb = NULL;
 111        struct inode *inode = NULL;
 112        struct dentry *root = NULL;
 113        struct v9fs_session_info *v9ses = NULL;
 114        struct p9_wstat *st = NULL;
 115        int mode = S_IRWXUGO | S_ISVTX;
 116        uid_t uid = current->fsuid;
 117        gid_t gid = current->fsgid;
 118        struct p9_fid *fid;
 119        int retval = 0;
 120
 121        P9_DPRINTK(P9_DEBUG_VFS, " \n");
 122
 123        st = NULL;
 124        v9ses = kzalloc(sizeof(struct v9fs_session_info), GFP_KERNEL);
 125        if (!v9ses)
 126                return -ENOMEM;
 127
 128        fid = v9fs_session_init(v9ses, dev_name, data);
 129        if (IS_ERR(fid)) {
 130                retval = PTR_ERR(fid);
 131                goto close_session;
 132        }
 133
 134        st = p9_client_stat(fid);
 135        if (IS_ERR(st)) {
 136                retval = PTR_ERR(st);
 137                goto clunk_fid;
 138        }
 139
 140        sb = sget(fs_type, NULL, v9fs_set_super, v9ses);
 141        if (IS_ERR(sb)) {
 142                retval = PTR_ERR(sb);
 143                goto free_stat;
 144        }
 145        v9fs_fill_super(sb, v9ses, flags);
 146
 147        inode = v9fs_get_inode(sb, S_IFDIR | mode);
 148        if (IS_ERR(inode)) {
 149                retval = PTR_ERR(inode);
 150                goto release_sb;
 151        }
 152
 153        inode->i_uid = uid;
 154        inode->i_gid = gid;
 155
 156        root = d_alloc_root(inode);
 157        if (!root) {
 158                retval = -ENOMEM;
 159                goto release_sb;
 160        }
 161
 162        sb->s_root = root;
 163        root->d_inode->i_ino = v9fs_qid2ino(&st->qid);
 164
 165        v9fs_stat2inode(st, root->d_inode, sb);
 166
 167        v9fs_fid_add(root, fid);
 168        p9stat_free(st);
 169        kfree(st);
 170
 171P9_DPRINTK(P9_DEBUG_VFS, " return simple set mount\n");
 172        return simple_set_mnt(mnt, sb);
 173
 174release_sb:
 175        if (sb) {
 176                up_write(&sb->s_umount);
 177                deactivate_super(sb);
 178        }
 179
 180free_stat:
 181        kfree(st);
 182
 183clunk_fid:
 184        p9_client_clunk(fid);
 185
 186close_session:
 187        v9fs_session_close(v9ses);
 188        kfree(v9ses);
 189
 190        return retval;
 191}
 192
 193/**
 194 * v9fs_kill_super - Kill Superblock
 195 * @s: superblock
 196 *
 197 */
 198
 199static void v9fs_kill_super(struct super_block *s)
 200{
 201        struct v9fs_session_info *v9ses = s->s_fs_info;
 202
 203        P9_DPRINTK(P9_DEBUG_VFS, " %p\n", s);
 204
 205        v9fs_dentry_release(s->s_root); /* clunk root */
 206
 207        kill_anon_super(s);
 208
 209        v9fs_session_close(v9ses);
 210        kfree(v9ses);
 211        P9_DPRINTK(P9_DEBUG_VFS, "exiting kill_super\n");
 212}
 213
 214/**
 215 * v9fs_show_options - Show mount options in /proc/mounts
 216 * @m: seq_file to write to
 217 * @mnt: mount descriptor
 218 *
 219 */
 220
 221static int v9fs_show_options(struct seq_file *m, struct vfsmount *mnt)
 222{
 223        struct v9fs_session_info *v9ses = mnt->mnt_sb->s_fs_info;
 224
 225        seq_printf(m, "%s", v9ses->options);
 226        return 0;
 227}
 228
 229static void
 230v9fs_umount_begin(struct super_block *sb)
 231{
 232        struct v9fs_session_info *v9ses = sb->s_fs_info;
 233
 234        v9fs_session_cancel(v9ses);
 235}
 236
 237static const struct super_operations v9fs_super_ops = {
 238        .statfs = simple_statfs,
 239        .clear_inode = v9fs_clear_inode,
 240        .show_options = v9fs_show_options,
 241        .umount_begin = v9fs_umount_begin,
 242};
 243
 244struct file_system_type v9fs_fs_type = {
 245        .name = "9p",
 246        .get_sb = v9fs_get_sb,
 247        .kill_sb = v9fs_kill_super,
 248        .owner = THIS_MODULE,
 249};
 250