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 <linux/smp_lock.h>
  41 #include <net/9p/9p.h>
  42 #include <net/9p/client.h>
  43
  44 #include "v9fs.h"
  45 #include "v9fs_vfs.h"
  46 #include "fid.h"
  47
  48 static void v9fs_clear_inode(struct inode *);
  49 static const struct super_operations v9fs_super_ops;
  50
  51 /**
  52  * v9fs_clear_inode - release an inode
  53  * @inode: inode to release
  54  *
  55  */
  56
  57 static void v9fs_clear_inode(struct inode *inode)
  58 {
  59         filemap_fdatawrite(inode->i_mapping);
  60 }
  61
  62 /**
  63  * v9fs_set_super - set the superblock
  64  * @s: super block
  65  * @data: file system specific data
  66  *
  67  */
  68
  69 static int v9fs_set_super(struct super_block *s, void *data)
  70 {
  71         s->s_fs_info = data;
  72         return set_anon_super(s, data);
  73 }
  74
  75 /**
  76  * v9fs_fill_super - populate superblock with info
  77  * @sb: superblock
  78  * @v9ses: session information
  79  * @flags: flags propagated from v9fs_get_sb()
  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  * @mnt: mountpoint record to be instantiated
 104  *
 105  */
 106
 107 static int v9fs_get_sb(struct file_system_type *fs_type, int flags,
 108                        const char *dev_name, void *data,
 109                        struct vfsmount *mnt)
 110 {
 111         struct super_block *sb = NULL;
 112         struct inode *inode = NULL;
 113         struct dentry *root = NULL;
 114         struct v9fs_session_info *v9ses = NULL;
 115         struct p9_wstat *st = NULL;
 116         int mode = S_IRWXUGO | S_ISVTX;
 117         uid_t uid = current_fsuid();
 118         gid_t gid = current_fsgid();
 119         struct p9_fid *fid;
 120         int retval = 0;
 121
 122         P9_DPRINTK(P9_DEBUG_VFS, " \n");
 123
 124         st = NULL;
 125         v9ses = kzalloc(sizeof(struct v9fs_session_info), GFP_KERNEL);
 126         if (!v9ses)
 127                 return -ENOMEM;
 128
 129         fid = v9fs_session_init(v9ses, dev_name, data);
 130         if (IS_ERR(fid)) {
 131                 retval = PTR_ERR(fid);
 132                 goto close_session;
 133         }
 134
 135         st = p9_client_stat(fid);
 136         if (IS_ERR(st)) {
 137                 retval = PTR_ERR(st);
 138                 goto clunk_fid;
 139         }
 140
 141         sb = sget(fs_type, NULL, v9fs_set_super, v9ses);
 142         if (IS_ERR(sb)) {
 143                 retval = PTR_ERR(sb);
 144                 goto free_stat;
 145         }
 146         v9fs_fill_super(sb, v9ses, flags);
 147
 148         inode = v9fs_get_inode(sb, S_IFDIR | mode);
 149         if (IS_ERR(inode)) {
 150                 retval = PTR_ERR(inode);
 151                 goto release_sb;
 152         }
 153
 154         inode->i_uid = uid;
 155         inode->i_gid = gid;
 156
 157         root = d_alloc_root(inode);
 158         if (!root) {
 159                 iput(inode);
 160                 retval = -ENOMEM;
 161                 goto release_sb;
 162         }
 163
 164         sb->s_root = root;
 165         root->d_inode->i_ino = v9fs_qid2ino(&st->qid);
 166
 167         v9fs_stat2inode(st, root->d_inode, sb);
 168
 169         v9fs_fid_add(root, fid);
 170         p9stat_free(st);
 171         kfree(st);
 172
 173 P9_DPRINTK(P9_DEBUG_VFS, " simple set mount, return 0\n");
 174         simple_set_mnt(mnt, sb);
 175         return 0;
 176
 177 release_sb:
 178         deactivate_locked_super(sb);
 179
 180 free_stat:
 181         kfree(st);
 182
 183 clunk_fid:
 184         p9_client_clunk(fid);
 185
 186 close_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
 199 static 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
 221 static 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
 229 static void
 230 v9fs_umount_begin(struct super_block *sb)
 231 {
 232         struct v9fs_session_info *v9ses;
 233
 234         lock_kernel();
 235         v9ses = sb->s_fs_info;
 236         v9fs_session_cancel(v9ses);
 237         unlock_kernel();
 238 }
 239
 240 static const struct super_operations v9fs_super_ops = {
 241         .statfs = simple_statfs,
 242         .clear_inode = v9fs_clear_inode,
 243         .show_options = v9fs_show_options,
 244         .umount_begin = v9fs_umount_begin,
 245 };
 246
 247 struct file_system_type v9fs_fs_type = {
 248         .name = "9p",
 249         .get_sb = v9fs_get_sb,
 250         .kill_sb = v9fs_kill_super,
 251         .owner = THIS_MODULE,
 252 };