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
  40 #include "debug.h"
  41 #include "v9fs.h"
  42 #include "9p.h"
  43 #include "v9fs_vfs.h"
  44 #include "fid.h"
  45
  46 static void v9fs_clear_inode(struct inode *);
  47 static const struct super_operations v9fs_super_ops;
  48
  49 /**
  50  * v9fs_clear_inode - release an inode
  51  * @inode: inode to release
  52  *
  53  */
  54
  55 static void v9fs_clear_inode(struct inode *inode)
  56 {
  57         filemap_fdatawrite(inode->i_mapping);
  58 }
  59
  60 /**
  61  * v9fs_set_super - set the superblock
  62  * @s: super block
  63  * @data: file system specific data
  64  *
  65  */
  66
  67 static int v9fs_set_super(struct super_block *s, void *data)
  68 {
  69         s->s_fs_info = data;
  70         return set_anon_super(s, data);
  71 }
  72
  73 /**
  74  * v9fs_fill_super - populate superblock with info
  75  * @sb: superblock
  76  * @v9ses: session information
  77  *
  78  */
  79
  80 static void
  81 v9fs_fill_super(struct super_block *sb, struct v9fs_session_info *v9ses,
  82                 int flags)
  83 {
  84         sb->s_maxbytes = MAX_LFS_FILESIZE;
  85         sb->s_blocksize_bits = fls(v9ses->maxdata - 1);
  86         sb->s_blocksize = 1 << sb->s_blocksize_bits;
  87         sb->s_magic = V9FS_MAGIC;
  88         sb->s_op = &v9fs_super_ops;
  89
  90         sb->s_flags = flags | MS_ACTIVE | MS_SYNCHRONOUS | MS_DIRSYNC |
  91             MS_NOATIME;
  92 }
  93
  94 /**
  95  * v9fs_get_sb - mount a superblock
  96  * @fs_type: file system type
  97  * @flags: mount flags
  98  * @dev_name: device name that was mounted
  99  * @data: mount options
 100  * @mnt: mountpoint record to be instantiated
 101  *
 102  */
 103
 104 static int v9fs_get_sb(struct file_system_type *fs_type, int flags,
 105                        const char *dev_name, void *data,
 106                        struct vfsmount *mnt)
 107 {
 108         struct super_block *sb = NULL;
 109         struct v9fs_fcall *fcall = NULL;
 110         struct inode *inode = NULL;
 111         struct dentry *root = NULL;
 112         struct v9fs_session_info *v9ses = NULL;
 113         struct v9fs_fid *root_fid = NULL;
 114         int mode = S_IRWXUGO | S_ISVTX;
 115         uid_t uid = current->fsuid;
 116         gid_t gid = current->fsgid;
 117         int stat_result = 0;
 118         int newfid = 0;
 119         int retval = 0;
 120
 121         dprintk(DEBUG_VFS, " \n");
 122
 123         v9ses = kzalloc(sizeof(struct v9fs_session_info), GFP_KERNEL);
 124         if (!v9ses)
 125                 return -ENOMEM;
 126
 127         if ((newfid = v9fs_session_init(v9ses, dev_name, data)) < 0) {
 128                 dprintk(DEBUG_ERROR, "problem initiating session\n");
 129                 retval = newfid;
 130                 goto out_free_session;
 131         }
 132
 133         sb = sget(fs_type, NULL, v9fs_set_super, v9ses);
 134         if (IS_ERR(sb)) {
 135                 retval = PTR_ERR(sb);
 136                 goto out_close_session;
 137         }
 138         v9fs_fill_super(sb, v9ses, flags);
 139
 140         inode = v9fs_get_inode(sb, S_IFDIR | mode);
 141         if (IS_ERR(inode)) {
 142                 retval = PTR_ERR(inode);
 143                 goto put_back_sb;
 144         }
 145
 146         inode->i_uid = uid;
 147         inode->i_gid = gid;
 148
 149         root = d_alloc_root(inode);
 150         if (!root) {
 151                 retval = -ENOMEM;
 152                 goto put_back_sb;
 153         }
 154
 155         sb->s_root = root;
 156
 157         stat_result = v9fs_t_stat(v9ses, newfid, &fcall);
 158         if (stat_result < 0) {
 159                 dprintk(DEBUG_ERROR, "stat error\n");
 160                 v9fs_t_clunk(v9ses, newfid);
 161         } else {
 162                 /* Setup the Root Inode */
 163                 root_fid = v9fs_fid_create(v9ses, newfid);
 164                 if (root_fid == NULL) {
 165                         retval = -ENOMEM;
 166                         goto put_back_sb;
 167                 }
 168
 169                 retval = v9fs_fid_insert(root_fid, root);
 170                 if (retval < 0) {
 171                         kfree(fcall);
 172                         goto put_back_sb;
 173                 }
 174
 175                 root_fid->qid = fcall->params.rstat.stat.qid;
 176                 root->d_inode->i_ino =
 177                     v9fs_qid2ino(&fcall->params.rstat.stat.qid);
 178                 v9fs_stat2inode(&fcall->params.rstat.stat, root->d_inode, sb);
 179         }
 180
 181         kfree(fcall);
 182
 183         if (stat_result < 0) {
 184                 retval = stat_result;
 185                 goto put_back_sb;
 186         }
 187
 188         return simple_set_mnt(mnt, sb);
 189
 190 out_close_session:
 191         v9fs_session_close(v9ses);
 192 out_free_session:
 193         kfree(v9ses);
 194         return retval;
 195
 196 put_back_sb:
 197         /* deactivate_super calls v9fs_kill_super which will frees the rest */
 198         up_write(&sb->s_umount);
 199         deactivate_super(sb);
 200         return retval;
 201 }
 202
 203 /**
 204  * v9fs_kill_super - Kill Superblock
 205  * @s: superblock
 206  *
 207  */
 208
 209 static void v9fs_kill_super(struct super_block *s)
 210 {
 211         struct v9fs_session_info *v9ses = s->s_fs_info;
 212
 213         dprintk(DEBUG_VFS, " %p\n", s);
 214
 215         v9fs_dentry_release(s->s_root); /* clunk root */
 216
 217         kill_anon_super(s);
 218
 219         v9fs_session_close(v9ses);
 220         kfree(v9ses);
 221         dprintk(DEBUG_VFS, "exiting kill_super\n");
 222 }
 223
 224 /**
 225  * v9fs_show_options - Show mount options in /proc/mounts
 226  * @m: seq_file to write to
 227  * @mnt: mount descriptor
 228  *
 229  */
 230
 231 static int v9fs_show_options(struct seq_file *m, struct vfsmount *mnt)
 232 {
 233         struct v9fs_session_info *v9ses = mnt->mnt_sb->s_fs_info;
 234
 235         if (v9ses->debug != 0)
 236                 seq_printf(m, ",debug=%u", v9ses->debug);
 237         if (v9ses->port != V9FS_PORT)
 238                 seq_printf(m, ",port=%u", v9ses->port);
 239         if (v9ses->maxdata != 9000)
 240                 seq_printf(m, ",msize=%u", v9ses->maxdata);
 241         if (v9ses->afid != ~0)
 242                 seq_printf(m, ",afid=%u", v9ses->afid);
 243         if (v9ses->proto == PROTO_UNIX)
 244                 seq_puts(m, ",proto=unix");
 245         if (v9ses->extended == 0)
 246                 seq_puts(m, ",noextend");
 247         if (v9ses->nodev == 1)
 248                 seq_puts(m, ",nodevmap");
 249         seq_printf(m, ",name=%s", v9ses->name);
 250         seq_printf(m, ",aname=%s", v9ses->remotename);
 251         seq_printf(m, ",uid=%u", v9ses->uid);
 252         seq_printf(m, ",gid=%u", v9ses->gid);
 253         return 0;
 254 }
 255
 256 static void
 257 v9fs_umount_begin(struct vfsmount *vfsmnt, int flags)
 258 {
 259         struct v9fs_session_info *v9ses = vfsmnt->mnt_sb->s_fs_info;
 260
 261         if (flags & MNT_FORCE)
 262                 v9fs_session_cancel(v9ses);
 263 }
 264
 265 static const struct super_operations v9fs_super_ops = {
 266         .statfs = simple_statfs,
 267         .clear_inode = v9fs_clear_inode,
 268         .show_options = v9fs_show_options,
 269         .umount_begin = v9fs_umount_begin,
 270 };
 271
 272 struct file_system_type v9fs_fs_type = {
 273         .name = "9p",
 274         .get_sb = v9fs_get_sb,
 275         .kill_sb = v9fs_kill_super,
 276         .owner = THIS_MODULE,
 277 };