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         sb->s_bdi = &v9ses->bdi;
  81
  82         sb->s_flags = flags | MS_ACTIVE | MS_SYNCHRONOUS | MS_DIRSYNC |
  83             MS_NOATIME;
  84
  85         save_mount_options(sb, data);
  86 }
  87
  88 /**
  89  * v9fs_get_sb - mount a superblock
  90  * @fs_type: file system type
  91  * @flags: mount flags
  92  * @dev_name: device name that was mounted
  93  * @data: mount options
  94  * @mnt: mountpoint record to be instantiated
  95  *
  96  */
  97
  98 static int v9fs_get_sb(struct file_system_type *fs_type, int flags,
  99                        const char *dev_name, void *data,
 100                        struct vfsmount *mnt)
 101 {
 102         struct super_block *sb = NULL;
 103         struct inode *inode = NULL;
 104         struct dentry *root = NULL;
 105         struct v9fs_session_info *v9ses = NULL;
 106         struct p9_wstat *st = NULL;
 107         int mode = S_IRWXUGO | S_ISVTX;
 108         struct p9_fid *fid;
 109         int retval = 0;
 110
 111         P9_DPRINTK(P9_DEBUG_VFS, " \n");
 112
 113         v9ses = kzalloc(sizeof(struct v9fs_session_info), GFP_KERNEL);
 114         if (!v9ses)
 115                 return -ENOMEM;
 116
 117         fid = v9fs_session_init(v9ses, dev_name, data);
 118         if (IS_ERR(fid)) {
 119                 retval = PTR_ERR(fid);
 120                 goto close_session;
 121         }
 122
 123         st = p9_client_stat(fid);
 124         if (IS_ERR(st)) {
 125                 retval = PTR_ERR(st);
 126                 goto clunk_fid;
 127         }
 128
 129         sb = sget(fs_type, NULL, v9fs_set_super, v9ses);
 130         if (IS_ERR(sb)) {
 131                 retval = PTR_ERR(sb);
 132                 goto free_stat;
 133         }
 134         v9fs_fill_super(sb, v9ses, flags, data);
 135
 136         inode = v9fs_get_inode(sb, S_IFDIR | mode);
 137         if (IS_ERR(inode)) {
 138                 retval = PTR_ERR(inode);
 139                 goto release_sb;
 140         }
 141
 142         root = d_alloc_root(inode);
 143         if (!root) {
 144                 iput(inode);
 145                 retval = -ENOMEM;
 146                 goto release_sb;
 147         }
 148
 149         sb->s_root = root;
 150         root->d_inode->i_ino = v9fs_qid2ino(&st->qid);
 151
 152         v9fs_stat2inode(st, root->d_inode, sb);
 153
 154         v9fs_fid_add(root, fid);
 155         p9stat_free(st);
 156         kfree(st);
 157
 158 P9_DPRINTK(P9_DEBUG_VFS, " simple set mount, return 0\n");
 159         simple_set_mnt(mnt, sb);
 160         return 0;
 161
 162 free_stat:
 163         p9stat_free(st);
 164         kfree(st);
 165
 166 clunk_fid:
 167         p9_client_clunk(fid);
 168
 169 close_session:
 170         v9fs_session_close(v9ses);
 171         kfree(v9ses);
 172         return retval;
 173
 174 release_sb:
 175         p9stat_free(st);
 176         kfree(st);
 177         deactivate_locked_super(sb);
 178         return retval;
 179 }
 180
 181 /**
 182  * v9fs_kill_super - Kill Superblock
 183  * @s: superblock
 184  *
 185  */
 186
 187 static void v9fs_kill_super(struct super_block *s)
 188 {
 189         struct v9fs_session_info *v9ses = s->s_fs_info;
 190
 191         P9_DPRINTK(P9_DEBUG_VFS, " %p\n", s);
 192
 193         if (s->s_root)
 194                 v9fs_dentry_release(s->s_root); /* clunk root */
 195
 196         kill_anon_super(s);
 197
 198         v9fs_session_cancel(v9ses);
 199         v9fs_session_close(v9ses);
 200         kfree(v9ses);
 201         s->s_fs_info = NULL;
 202         P9_DPRINTK(P9_DEBUG_VFS, "exiting kill_super\n");
 203 }
 204
 205 static void
 206 v9fs_umount_begin(struct super_block *sb)
 207 {
 208         struct v9fs_session_info *v9ses;
 209
 210         v9ses = sb->s_fs_info;
 211         v9fs_session_begin_cancel(v9ses);
 212 }
 213
 214 static const struct super_operations v9fs_super_ops = {
 215 #ifdef CONFIG_9P_FSCACHE
 216         .alloc_inode = v9fs_alloc_inode,
 217         .destroy_inode = v9fs_destroy_inode,
 218 #endif
 219         .statfs = simple_statfs,
 220         .clear_inode = v9fs_clear_inode,
 221         .show_options = generic_show_options,
 222         .umount_begin = v9fs_umount_begin,
 223 };
 224
 225 struct file_system_type v9fs_fs_type = {
 226         .name = "9p",
 227         .get_sb = v9fs_get_sb,
 228         .kill_sb = v9fs_kill_super,
 229         .owner = THIS_MODULE,
 230 };