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 const struct super_operations v9fs_super_ops;
  48
  49 /**
  50  * v9fs_set_super - set the superblock
  51  * @s: super block
  52  * @data: file system specific data
  53  *
  54  */
  55
  56 static int v9fs_set_super(struct super_block *s, void *data)
  57 {
  58         s->s_fs_info = data;
  59         return set_anon_super(s, data);
  60 }
  61
  62 /**
  63  * v9fs_fill_super - populate superblock with info
  64  * @sb: superblock
  65  * @v9ses: session information
  66  * @flags: flags propagated from v9fs_get_sb()
  67  *
  68  */
  69
  70 static void
  71 v9fs_fill_super(struct super_block *sb, struct v9fs_session_info *v9ses,
  72                 int flags, void *data)
  73 {
  74         sb->s_maxbytes = MAX_LFS_FILESIZE;
  75         sb->s_blocksize_bits = fls(v9ses->maxdata - 1);
  76         sb->s_blocksize = 1 << sb->s_blocksize_bits;
  77         sb->s_magic = V9FS_MAGIC;
  78         sb->s_op = &v9fs_super_ops;
  79
  80         sb->s_flags = flags | MS_ACTIVE | MS_SYNCHRONOUS | MS_DIRSYNC |
  81             MS_NOATIME;
  82
  83         save_mount_options(sb, data);
  84 }
  85
  86 /**
  87  * v9fs_get_sb - mount a superblock
  88  * @fs_type: file system type
  89  * @flags: mount flags
  90  * @dev_name: device name that was mounted
  91  * @data: mount options
  92  * @mnt: mountpoint record to be instantiated
  93  *
  94  */
  95
  96 static int v9fs_get_sb(struct file_system_type *fs_type, int flags,
  97                        const char *dev_name, void *data,
  98                        struct vfsmount *mnt)
  99 {
 100         struct super_block *sb = NULL;
 101         struct inode *inode = NULL;
 102         struct dentry *root = NULL;
 103         struct v9fs_session_info *v9ses = NULL;
 104         struct p9_wstat *st = NULL;
 105         int mode = S_IRWXUGO | S_ISVTX;
 106         struct p9_fid *fid;
 107         int retval = 0;
 108
 109         P9_DPRINTK(P9_DEBUG_VFS, " \n");
 110
 111         v9ses = kzalloc(sizeof(struct v9fs_session_info), GFP_KERNEL);
 112         if (!v9ses)
 113                 return -ENOMEM;
 114
 115         fid = v9fs_session_init(v9ses, dev_name, data);
 116         if (IS_ERR(fid)) {
 117                 retval = PTR_ERR(fid);
 118                 goto close_session;
 119         }
 120
 121         st = p9_client_stat(fid);
 122         if (IS_ERR(st)) {
 123                 retval = PTR_ERR(st);
 124                 goto clunk_fid;
 125         }
 126
 127         sb = sget(fs_type, NULL, v9fs_set_super, v9ses);
 128         if (IS_ERR(sb)) {
 129                 retval = PTR_ERR(sb);
 130                 goto free_stat;
 131         }
 132         v9fs_fill_super(sb, v9ses, flags, data);
 133
 134         inode = v9fs_get_inode(sb, S_IFDIR | mode);
 135         if (IS_ERR(inode)) {
 136                 retval = PTR_ERR(inode);
 137                 goto release_sb;
 138         }
 139
 140         root = d_alloc_root(inode);
 141         if (!root) {
 142                 iput(inode);
 143                 retval = -ENOMEM;
 144                 goto release_sb;
 145         }
 146
 147         sb->s_root = root;
 148         root->d_inode->i_ino = v9fs_qid2ino(&st->qid);
 149
 150         v9fs_stat2inode(st, root->d_inode, sb);
 151
 152         v9fs_fid_add(root, fid);
 153         p9stat_free(st);
 154         kfree(st);
 155
 156 P9_DPRINTK(P9_DEBUG_VFS, " simple set mount, return 0\n");
 157         simple_set_mnt(mnt, sb);
 158         return 0;
 159
 160 free_stat:
 161         p9stat_free(st);
 162         kfree(st);
 163
 164 clunk_fid:
 165         p9_client_clunk(fid);
 166
 167 close_session:
 168         v9fs_session_close(v9ses);
 169         kfree(v9ses);
 170         return retval;
 171
 172 release_sb:
 173         p9stat_free(st);
 174         kfree(st);
 175         deactivate_locked_super(sb);
 176         return retval;
 177 }
 178
 179 /**
 180  * v9fs_kill_super - Kill Superblock
 181  * @s: superblock
 182  *
 183  */
 184
 185 static void v9fs_kill_super(struct super_block *s)
 186 {
 187         struct v9fs_session_info *v9ses = s->s_fs_info;
 188
 189         P9_DPRINTK(P9_DEBUG_VFS, " %p\n", s);
 190
 191         v9fs_dentry_release(s->s_root); /* clunk root */
 192
 193         kill_anon_super(s);
 194
 195         v9fs_session_close(v9ses);
 196         kfree(v9ses);
 197         s->s_fs_info = NULL;
 198         P9_DPRINTK(P9_DEBUG_VFS, "exiting kill_super\n");
 199 }
 200
 201 static void
 202 v9fs_umount_begin(struct super_block *sb)
 203 {
 204         struct v9fs_session_info *v9ses;
 205
 206         v9ses = sb->s_fs_info;
 207         v9fs_session_cancel(v9ses);
 208 }
 209
 210 static const struct super_operations v9fs_super_ops = {
 211 #ifdef CONFIG_9P_FSCACHE
 212         .alloc_inode = v9fs_alloc_inode,
 213         .destroy_inode = v9fs_destroy_inode,
 214 #endif
 215         .statfs = simple_statfs,
 216         .clear_inode = v9fs_clear_inode,
 217         .show_options = generic_show_options,
 218         .umount_begin = v9fs_umount_begin,
 219 };
 220
 221 struct file_system_type v9fs_fs_type = {
 222         .name = "9p",
 223         .get_sb = v9fs_get_sb,
 224         .kill_sb = v9fs_kill_super,
 225         .owner = THIS_MODULE,
 226 };