fs/9p/vfs_super.c

   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 as published by
  12  *  the Free Software Foundation; either version 2 of the License, or
  13  *  (at your option) any later version.
  14  *
  15  *  This program is distributed in the hope that it will be useful,
  16  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  *  GNU General Public License for more details.
  19  *
  20  *  You should have received a copy of the GNU General Public License
  21  *  along with this program; if not, write to:
  22  *  Free Software Foundation
  23  *  51 Franklin Street, Fifth Floor
  24  *  Boston, MA  02111-1301  USA
  25  *
  26  */
  27
  28 #include <linux/kernel.h>
  29 #include <linux/config.h>
  30 #include <linux/module.h>
  31 #include <linux/errno.h>
  32 #include <linux/fs.h>
  33 #include <linux/file.h>
  34 #include <linux/stat.h>
  35 #include <linux/string.h>
  36 #include <linux/smp_lock.h>
  37 #include <linux/inet.h>
  38 #include <linux/pagemap.h>
  39 #include <linux/seq_file.h>
  40 #include <linux/mount.h>
  41 #include <linux/idr.h>
  42
  43 #include "debug.h"
  44 #include "v9fs.h"
  45 #include "9p.h"
  46 #include "v9fs_vfs.h"
  47 #include "fid.h"
  48
  49 static void v9fs_clear_inode(struct inode *);
  50 static struct super_operations v9fs_super_ops;
  51
  52 /**
  53  * v9fs_clear_inode - release an inode
  54  * @inode: inode to release
  55  *
  56  */
  57
  58 static void v9fs_clear_inode(struct inode *inode)
  59 {
  60         filemap_fdatawrite(inode->i_mapping);
  61 }
  62
  63 /**
  64  * v9fs_set_super - set the superblock
  65  * @s: super block
  66  * @data: file system specific data
  67  *
  68  */
  69
  70 static int v9fs_set_super(struct super_block *s, void *data)
  71 {
  72         s->s_fs_info = data;
  73         return set_anon_super(s, data);
  74 }
  75
  76 /**
  77  * v9fs_fill_super - populate superblock with info
  78  * @sb: superblock
  79  * @v9ses: session information
  80  *
  81  */
  82
  83 static void
  84 v9fs_fill_super(struct super_block *sb, struct v9fs_session_info *v9ses,
  85                 int flags)
  86 {
  87         sb->s_maxbytes = MAX_LFS_FILESIZE;
  88         sb->s_blocksize_bits = fls(v9ses->maxdata - 1);
  89         sb->s_blocksize = 1 << sb->s_blocksize_bits;
  90         sb->s_magic = V9FS_MAGIC;
  91         sb->s_op = &v9fs_super_ops;
  92
  93         sb->s_flags = flags | MS_ACTIVE | MS_SYNCHRONOUS | MS_DIRSYNC |
  94             MS_NOATIME;
  95 }
  96
  97 /**
  98  * v9fs_get_sb - mount a superblock
  99  * @fs_type: file system type
 100  * @flags: mount flags
 101  * @dev_name: device name that was mounted
 102  * @data: mount options
 103  *
 104  */
 105
 106 static struct super_block *v9fs_get_sb(struct file_system_type
 107                                        *fs_type, int flags,
 108                                        const char *dev_name, void *data)
 109 {
 110         struct super_block *sb = NULL;
 111         struct v9fs_fcall *fcall = NULL;
 112         struct inode *inode = NULL;
 113         struct dentry *root = NULL;
 114         struct v9fs_session_info *v9ses = NULL;
 115         struct v9fs_fid *root_fid = NULL;
 116         int mode = S_IRWXUGO | S_ISVTX;
 117         uid_t uid = current->fsuid;
 118         gid_t gid = current->fsgid;
 119         int stat_result = 0;
 120         int newfid = 0;
 121         int retval = 0;
 122
 123         dprintk(DEBUG_VFS, " \n");
 124
 125         v9ses = kzalloc(sizeof(struct v9fs_session_info), GFP_KERNEL);
 126         if (!v9ses)
 127                 return ERR_PTR(-ENOMEM);
 128
 129         if ((newfid = v9fs_session_init(v9ses, dev_name, data)) < 0) {
 130                 dprintk(DEBUG_ERROR, "problem initiating session\n");
 131                 kfree(v9ses);
 132                 return ERR_PTR(newfid);
 133         }
 134
 135         sb = sget(fs_type, NULL, v9fs_set_super, v9ses);
 136
 137         v9fs_fill_super(sb, v9ses, flags);
 138
 139         inode = v9fs_get_inode(sb, S_IFDIR | mode);
 140         if (IS_ERR(inode)) {
 141                 retval = PTR_ERR(inode);
 142                 goto put_back_sb;
 143         }
 144
 145         inode->i_uid = uid;
 146         inode->i_gid = gid;
 147
 148         root = d_alloc_root(inode);
 149         if (!root) {
 150                 retval = -ENOMEM;
 151                 goto put_back_sb;
 152         }
 153
 154         sb->s_root = root;
 155
 156         stat_result = v9fs_t_stat(v9ses, newfid, &fcall);
 157         if (stat_result < 0) {
 158                 dprintk(DEBUG_ERROR, "stat error\n");
 159                 v9fs_t_clunk(v9ses, newfid);
 160         } else {
 161                 /* Setup the Root Inode */
 162                 root_fid = v9fs_fid_create(v9ses, newfid);
 163                 if (root_fid == NULL) {
 164                         retval = -ENOMEM;
 165                         goto put_back_sb;
 166                 }
 167
 168                 retval = v9fs_fid_insert(root_fid, root);
 169                 if (retval < 0) {
 170                         kfree(fcall);
 171                         goto put_back_sb;
 172                 }
 173
 174                 root_fid->qid = fcall->params.rstat.stat.qid;
 175                 root->d_inode->i_ino =
 176                     v9fs_qid2ino(&fcall->params.rstat.stat.qid);
 177                 v9fs_stat2inode(&fcall->params.rstat.stat, root->d_inode, sb);
 178         }
 179
 180         kfree(fcall);
 181
 182         if (stat_result < 0) {
 183                 retval = stat_result;
 184                 goto put_back_sb;
 185         }
 186
 187         return sb;
 188
 189 put_back_sb:
 190         /* deactivate_super calls v9fs_kill_super which will frees the rest */
 191         up_write(&sb->s_umount);
 192         deactivate_super(sb);
 193         return ERR_PTR(retval);
 194 }
 195
 196 /**
 197  * v9fs_kill_super - Kill Superblock
 198  * @s: superblock
 199  *
 200  */
 201
 202 static void v9fs_kill_super(struct super_block *s)
 203 {
 204         struct v9fs_session_info *v9ses = s->s_fs_info;
 205
 206         dprintk(DEBUG_VFS, " %p\n", s);
 207
 208         v9fs_dentry_release(s->s_root); /* clunk root */
 209
 210         kill_anon_super(s);
 211
 212         v9fs_session_close(v9ses);
 213         kfree(v9ses);
 214         dprintk(DEBUG_VFS, "exiting kill_super\n");
 215 }
 216
 217 /**
 218  * v9fs_show_options - Show mount options in /proc/mounts
 219  * @m: seq_file to write to
 220  * @mnt: mount descriptor
 221  *
 222  */
 223
 224 static int v9fs_show_options(struct seq_file *m, struct vfsmount *mnt)
 225 {
 226         struct v9fs_session_info *v9ses = mnt->mnt_sb->s_fs_info;
 227
 228         if (v9ses->debug != 0)
 229                 seq_printf(m, ",debug=%u", v9ses->debug);
 230         if (v9ses->port != V9FS_PORT)
 231                 seq_printf(m, ",port=%u", v9ses->port);
 232         if (v9ses->maxdata != 9000)
 233                 seq_printf(m, ",msize=%u", v9ses->maxdata);
 234         if (v9ses->afid != ~0)
 235                 seq_printf(m, ",afid=%u", v9ses->afid);
 236         if (v9ses->proto == PROTO_UNIX)
 237                 seq_puts(m, ",proto=unix");
 238         if (v9ses->extended == 0)
 239                 seq_puts(m, ",noextend");
 240         if (v9ses->nodev == 1)
 241                 seq_puts(m, ",nodevmap");
 242         seq_printf(m, ",name=%s", v9ses->name);
 243         seq_printf(m, ",aname=%s", v9ses->remotename);
 244         seq_printf(m, ",uid=%u", v9ses->uid);
 245         seq_printf(m, ",gid=%u", v9ses->gid);
 246         return 0;
 247 }
 248
 249 static void
 250 v9fs_umount_begin(struct super_block *sb)
 251 {
 252         struct v9fs_session_info *v9ses = sb->s_fs_info;
 253
 254         v9fs_session_cancel(v9ses);
 255 }
 256
 257 static struct super_operations v9fs_super_ops = {
 258         .statfs = simple_statfs,
 259         .clear_inode = v9fs_clear_inode,
 260         .show_options = v9fs_show_options,
 261         .umount_begin = v9fs_umount_begin,
 262 };
 263
 264 struct file_system_type v9fs_fs_type = {
 265         .name = "9P",
 266         .get_sb = v9fs_get_sb,
 267         .kill_sb = v9fs_kill_super,
 268         .owner = THIS_MODULE,
 269 };