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 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
  41 #include "debug.h"
  42 #include "v9fs.h"
  43 #include "9p.h"
  44 #include "v9fs_vfs.h"
  45 #include "fid.h"
  46
  47 static void v9fs_clear_inode(struct inode *);
  48 static const struct super_operations v9fs_super_ops;
  49
  50 /**
  51  * v9fs_clear_inode - release an inode
  52  * @inode: inode to release
  53  *
  54  */
  55
  56 static 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
  68 static 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  *
  79  */
  80
  81 static void
  82 v9fs_fill_super(struct super_block *sb, struct v9fs_session_info *v9ses,
  83                 int flags)
  84 {
  85         sb->s_maxbytes = MAX_LFS_FILESIZE;
  86         sb->s_blocksize_bits = fls(v9ses->maxdata - 1);
  87         sb->s_blocksize = 1 << sb->s_blocksize_bits;
  88         sb->s_magic = V9FS_MAGIC;
  89         sb->s_op = &v9fs_super_ops;
  90
  91         sb->s_flags = flags | MS_ACTIVE | MS_SYNCHRONOUS | MS_DIRSYNC |
  92             MS_NOATIME;
  93 }
  94
  95 /**
  96  * v9fs_get_sb - mount a superblock
  97  * @fs_type: file system type
  98  * @flags: mount flags
  99  * @dev_name: device name that was mounted
 100  * @data: mount options
 101  * @mnt: mountpoint record to be instantiated
 102  *
 103  */
 104
 105 static int v9fs_get_sb(struct file_system_type *fs_type, int flags,
 106                        const char *dev_name, void *data,
 107                        struct vfsmount *mnt)
 108 {
 109         struct super_block *sb = NULL;
 110         struct v9fs_fcall *fcall = NULL;
 111         struct inode *inode = NULL;
 112         struct dentry *root = NULL;
 113         struct v9fs_session_info *v9ses = NULL;
 114         struct v9fs_fid *root_fid = NULL;
 115         int mode = S_IRWXUGO | S_ISVTX;
 116         uid_t uid = current->fsuid;
 117         gid_t gid = current->fsgid;
 118         int stat_result = 0;
 119         int newfid = 0;
 120         int retval = 0;
 121
 122         dprintk(DEBUG_VFS, " \n");
 123
 124         v9ses = kzalloc(sizeof(struct v9fs_session_info), GFP_KERNEL);
 125         if (!v9ses)
 126                 return -ENOMEM;
 127
 128         if ((newfid = v9fs_session_init(v9ses, dev_name, data)) < 0) {
 129                 dprintk(DEBUG_ERROR, "problem initiating session\n");
 130                 retval = newfid;
 131                 goto out_free_session;
 132         }
 133
 134         sb = sget(fs_type, NULL, v9fs_set_super, v9ses);
 135         if (IS_ERR(sb)) {
 136                 retval = PTR_ERR(sb);
 137                 goto out_close_session;
 138         }
 139         v9fs_fill_super(sb, v9ses, flags);
 140
 141         inode = v9fs_get_inode(sb, S_IFDIR | mode);
 142         if (IS_ERR(inode)) {
 143                 retval = PTR_ERR(inode);
 144                 goto put_back_sb;
 145         }
 146
 147         inode->i_uid = uid;
 148         inode->i_gid = gid;
 149
 150         root = d_alloc_root(inode);
 151         if (!root) {
 152                 retval = -ENOMEM;
 153                 goto put_back_sb;
 154         }
 155
 156         sb->s_root = root;
 157
 158         stat_result = v9fs_t_stat(v9ses, newfid, &fcall);
 159         if (stat_result < 0) {
 160                 dprintk(DEBUG_ERROR, "stat error\n");
 161                 v9fs_t_clunk(v9ses, newfid);
 162         } else {
 163                 /* Setup the Root Inode */
 164                 root_fid = v9fs_fid_create(v9ses, newfid);
 165                 if (root_fid == NULL) {
 166                         retval = -ENOMEM;
 167                         goto put_back_sb;
 168                 }
 169
 170                 retval = v9fs_fid_insert(root_fid, root);
 171                 if (retval < 0) {
 172                         kfree(fcall);
 173                         goto put_back_sb;
 174                 }
 175
 176                 root_fid->qid = fcall->params.rstat.stat.qid;
 177                 root->d_inode->i_ino =
 178                     v9fs_qid2ino(&fcall->params.rstat.stat.qid);
 179                 v9fs_stat2inode(&fcall->params.rstat.stat, root->d_inode, sb);
 180         }
 181
 182         kfree(fcall);
 183
 184         if (stat_result < 0) {
 185                 retval = stat_result;
 186                 goto put_back_sb;
 187         }
 188
 189         return simple_set_mnt(mnt, sb);
 190
 191 out_close_session:
 192         v9fs_session_close(v9ses);
 193 out_free_session:
 194         kfree(v9ses);
 195         return retval;
 196
 197 put_back_sb:
 198         /* deactivate_super calls v9fs_kill_super which will frees the rest */
 199         up_write(&sb->s_umount);
 200         deactivate_super(sb);
 201         return retval;
 202 }
 203
 204 /**
 205  * v9fs_kill_super - Kill Superblock
 206  * @s: superblock
 207  *
 208  */
 209
 210 static void v9fs_kill_super(struct super_block *s)
 211 {
 212         struct v9fs_session_info *v9ses = s->s_fs_info;
 213
 214         dprintk(DEBUG_VFS, " %p\n", s);
 215
 216         v9fs_dentry_release(s->s_root); /* clunk root */
 217
 218         kill_anon_super(s);
 219
 220         v9fs_session_close(v9ses);
 221         kfree(v9ses);
 222         dprintk(DEBUG_VFS, "exiting kill_super\n");
 223 }
 224
 225 /**
 226  * v9fs_show_options - Show mount options in /proc/mounts
 227  * @m: seq_file to write to
 228  * @mnt: mount descriptor
 229  *
 230  */
 231
 232 static int v9fs_show_options(struct seq_file *m, struct vfsmount *mnt)
 233 {
 234         struct v9fs_session_info *v9ses = mnt->mnt_sb->s_fs_info;
 235
 236         if (v9ses->debug != 0)
 237                 seq_printf(m, ",debug=%u", v9ses->debug);
 238         if (v9ses->port != V9FS_PORT)
 239                 seq_printf(m, ",port=%u", v9ses->port);
 240         if (v9ses->maxdata != 9000)
 241                 seq_printf(m, ",msize=%u", v9ses->maxdata);
 242         if (v9ses->afid != ~0)
 243                 seq_printf(m, ",afid=%u", v9ses->afid);
 244         if (v9ses->proto == PROTO_UNIX)
 245                 seq_puts(m, ",proto=unix");
 246         if (v9ses->extended == 0)
 247                 seq_puts(m, ",noextend");
 248         if (v9ses->nodev == 1)
 249                 seq_puts(m, ",nodevmap");
 250         seq_printf(m, ",name=%s", v9ses->name);
 251         seq_printf(m, ",aname=%s", v9ses->remotename);
 252         seq_printf(m, ",uid=%u", v9ses->uid);
 253         seq_printf(m, ",gid=%u", v9ses->gid);
 254         return 0;
 255 }
 256
 257 static void
 258 v9fs_umount_begin(struct vfsmount *vfsmnt, int flags)
 259 {
 260         struct v9fs_session_info *v9ses = vfsmnt->mnt_sb->s_fs_info;
 261
 262         if (flags & MNT_FORCE)
 263                 v9fs_session_cancel(v9ses);
 264 }
 265
 266 static const struct super_operations v9fs_super_ops = {
 267         .statfs = simple_statfs,
 268         .clear_inode = v9fs_clear_inode,
 269         .show_options = v9fs_show_options,
 270         .umount_begin = v9fs_umount_begin,
 271 };
 272
 273 struct file_system_type v9fs_fs_type = {
 274         .name = "9p",
 275         .get_sb = v9fs_get_sb,
 276         .kill_sb = v9fs_kill_super,
 277         .owner = THIS_MODULE,
 278 };