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/slab.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 const struct super_operations v9fs_super_ops;
  49
  50 /**
  51  * v9fs_set_super - set the superblock
  52  * @s: super block
  53  * @data: file system specific data
  54  *
  55  */
  56
  57 static int v9fs_set_super(struct super_block *s, void *data)
  58 {
  59         s->s_fs_info = data;
  60         return set_anon_super(s, data);
  61 }
  62
  63 /**
  64  * v9fs_fill_super - populate superblock with info
  65  * @sb: superblock
  66  * @v9ses: session information
  67  * @flags: flags propagated from v9fs_get_sb()
  68  *
  69  */
  70
  71 static void
  72 v9fs_fill_super(struct super_block *sb, struct v9fs_session_info *v9ses,
  73                 int flags, void *data)
  74 {
  75         sb->s_maxbytes = MAX_LFS_FILESIZE;
  76         sb->s_blocksize_bits = fls(v9ses->maxdata - 1);
  77         sb->s_blocksize = 1 << sb->s_blocksize_bits;
  78         sb->s_magic = V9FS_MAGIC;
  79         sb->s_op = &v9fs_super_ops;
  80
  81         sb->s_flags = flags | MS_ACTIVE | MS_SYNCHRONOUS | MS_DIRSYNC |
  82             MS_NOATIME;
  83
  84         save_mount_options(sb, data);
  85 }
  86
  87 /**
  88  * v9fs_get_sb - mount a superblock
  89  * @fs_type: file system type
  90  * @flags: mount flags
  91  * @dev_name: device name that was mounted
  92  * @data: mount options
  93  * @mnt: mountpoint record to be instantiated
  94  *
  95  */
  96
  97 static int v9fs_get_sb(struct file_system_type *fs_type, int flags,
  98                        const char *dev_name, void *data,
  99                        struct vfsmount *mnt)
 100 {
 101         struct super_block *sb = NULL;
 102         struct inode *inode = NULL;
 103         struct dentry *root = NULL;
 104         struct v9fs_session_info *v9ses = NULL;
 105         struct p9_wstat *st = NULL;
 106         int mode = S_IRWXUGO | S_ISVTX;
 107         struct p9_fid *fid;
 108         int retval = 0;
 109
 110         P9_DPRINTK(P9_DEBUG_VFS, " \n");
 111
 112         v9ses = kzalloc(sizeof(struct v9fs_session_info), GFP_KERNEL);
 113         if (!v9ses)
 114                 return -ENOMEM;
 115
 116         fid = v9fs_session_init(v9ses, dev_name, data);
 117         if (IS_ERR(fid)) {
 118                 retval = PTR_ERR(fid);
 119                 goto close_session;
 120         }
 121
 122         st = p9_client_stat(fid);
 123         if (IS_ERR(st)) {
 124                 retval = PTR_ERR(st);
 125                 goto clunk_fid;
 126         }
 127
 128         sb = sget(fs_type, NULL, v9fs_set_super, v9ses);
 129         if (IS_ERR(sb)) {
 130                 retval = PTR_ERR(sb);
 131                 goto free_stat;
 132         }
 133         v9fs_fill_super(sb, v9ses, flags, data);
 134
 135         inode = v9fs_get_inode(sb, S_IFDIR | mode);
 136         if (IS_ERR(inode)) {
 137                 retval = PTR_ERR(inode);
 138                 goto release_sb;
 139         }
 140
 141         root = d_alloc_root(inode);
 142         if (!root) {
 143                 iput(inode);
 144                 retval = -ENOMEM;
 145                 goto release_sb;
 146         }
 147
 148         sb->s_root = root;
 149         root->d_inode->i_ino = v9fs_qid2ino(&st->qid);
 150
 151         v9fs_stat2inode(st, root->d_inode, sb);
 152
 153         v9fs_fid_add(root, fid);
 154         p9stat_free(st);
 155         kfree(st);
 156
 157 P9_DPRINTK(P9_DEBUG_VFS, " simple set mount, return 0\n");
 158         simple_set_mnt(mnt, sb);
 159         return 0;
 160
 161 free_stat:
 162         p9stat_free(st);
 163         kfree(st);
 164
 165 clunk_fid:
 166         p9_client_clunk(fid);
 167
 168 close_session:
 169         v9fs_session_close(v9ses);
 170         kfree(v9ses);
 171         return retval;
 172
 173 release_sb:
 174         p9stat_free(st);
 175         kfree(st);
 176         deactivate_locked_super(sb);
 177         return retval;
 178 }
 179
 180 /**
 181  * v9fs_kill_super - Kill Superblock
 182  * @s: superblock
 183  *
 184  */
 185
 186 static void v9fs_kill_super(struct super_block *s)
 187 {
 188         struct v9fs_session_info *v9ses = s->s_fs_info;
 189
 190         P9_DPRINTK(P9_DEBUG_VFS, " %p\n", s);
 191
 192         if (s->s_root)
 193                 v9fs_dentry_release(s->s_root); /* clunk root */
 194
 195         kill_anon_super(s);
 196
 197         v9fs_session_cancel(v9ses);
 198         v9fs_session_close(v9ses);
 199         kfree(v9ses);
 200         s->s_fs_info = NULL;
 201         P9_DPRINTK(P9_DEBUG_VFS, "exiting kill_super\n");
 202 }
 203
 204 static void
 205 v9fs_umount_begin(struct super_block *sb)
 206 {
 207         struct v9fs_session_info *v9ses;
 208
 209         v9ses = sb->s_fs_info;
 210         v9fs_session_begin_cancel(v9ses);
 211 }
 212
 213 static const struct super_operations v9fs_super_ops = {
 214 #ifdef CONFIG_9P_FSCACHE
 215         .alloc_inode = v9fs_alloc_inode,
 216         .destroy_inode = v9fs_destroy_inode,
 217 #endif
 218         .statfs = simple_statfs,
 219         .clear_inode = v9fs_clear_inode,
 220         .show_options = generic_show_options,
 221         .umount_begin = v9fs_umount_begin,
 222 };
 223
 224 struct file_system_type v9fs_fs_type = {
 225         .name = "9p",
 226         .get_sb = v9fs_get_sb,
 227         .kill_sb = v9fs_kill_super,
 228         .owner = THIS_MODULE,
 229 };