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 #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
  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  * @flags: flags propagated from v9fs_get_sb()
  79  *
  80  */
  81
  82 static void
  83 v9fs_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
 106 static 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_stat *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         v9fs_stat2inode(st, root->d_inode, sb);
 165         v9fs_fid_add(root, fid);
 166         kfree(st);
 167
 168         return simple_set_mnt(mnt, sb);
 169
 170 release_sb:
 171         if (sb) {
 172                 up_write(&sb->s_umount);
 173                 deactivate_super(sb);
 174         }
 175
 176 free_stat:
 177         kfree(st);
 178
 179 clunk_fid:
 180         p9_client_clunk(fid);
 181
 182 close_session:
 183         v9fs_session_close(v9ses);
 184         kfree(v9ses);
 185
 186         return retval;
 187 }
 188
 189 /**
 190  * v9fs_kill_super - Kill Superblock
 191  * @s: superblock
 192  *
 193  */
 194
 195 static void v9fs_kill_super(struct super_block *s)
 196 {
 197         struct v9fs_session_info *v9ses = s->s_fs_info;
 198
 199         P9_DPRINTK(P9_DEBUG_VFS, " %p\n", s);
 200
 201         v9fs_dentry_release(s->s_root); /* clunk root */
 202
 203         kill_anon_super(s);
 204
 205         v9fs_session_close(v9ses);
 206         kfree(v9ses);
 207         P9_DPRINTK(P9_DEBUG_VFS, "exiting kill_super\n");
 208 }
 209
 210 /**
 211  * v9fs_show_options - Show mount options in /proc/mounts
 212  * @m: seq_file to write to
 213  * @mnt: mount descriptor
 214  *
 215  */
 216
 217 static int v9fs_show_options(struct seq_file *m, struct vfsmount *mnt)
 218 {
 219         struct v9fs_session_info *v9ses = mnt->mnt_sb->s_fs_info;
 220
 221         seq_printf(m, "%s", v9ses->options);
 222         return 0;
 223 }
 224
 225 static void
 226 v9fs_umount_begin(struct super_block *sb)
 227 {
 228         struct v9fs_session_info *v9ses = sb->s_fs_info;
 229
 230         v9fs_session_cancel(v9ses);
 231 }
 232
 233 static const struct super_operations v9fs_super_ops = {
 234         .statfs = simple_statfs,
 235         .clear_inode = v9fs_clear_inode,
 236         .show_options = v9fs_show_options,
 237         .umount_begin = v9fs_umount_begin,
 238 };
 239
 240 struct file_system_type v9fs_fs_type = {
 241         .name = "9p",
 242         .get_sb = v9fs_get_sb,
 243         .kill_sb = v9fs_kill_super,
 244         .owner = THIS_MODULE,
 245 };