arch/ia64/sn/io/hwgfs/ramfs.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (c) 2003 Silicon Graphics, Inc.  All Rights Reserved.
   7  *
   8  *  Mostly shameless copied from Linus Torvalds' ramfs and thus
   9  *  Copyright (C) 2000 Linus Torvalds.
  10  *                2000 Transmeta Corp.
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/backing-dev.h>
  15 #include <linux/fs.h>
  16 #include <linux/pagemap.h>
  17 #include <linux/init.h>
  18 #include <linux/string.h>
  19 #include <asm/uaccess.h>
  20
  21 /* some random number */
  22 #define HWGFS_MAGIC     0x12061983
  23
  24 static struct super_operations hwgfs_ops;
  25 static struct address_space_operations hwgfs_aops;
  26 static struct file_operations hwgfs_file_operations;
  27 static struct inode_operations hwgfs_file_inode_operations;
  28 static struct inode_operations hwgfs_dir_inode_operations;
  29
  30 static struct backing_dev_info hwgfs_backing_dev_info = {
  31         .ra_pages       = 0,    /* No readahead */
  32         .memory_backed  = 1,    /* Does not contribute to dirty memory */
  33 };
  34
  35 static struct inode *hwgfs_get_inode(struct super_block *sb, int mode, dev_t dev)
  36 {
  37         struct inode * inode = new_inode(sb);
  38
  39         if (inode) {
  40                 inode->i_mode = mode;
  41                 inode->i_uid = current->fsuid;
  42                 inode->i_gid = current->fsgid;
  43                 inode->i_blksize = PAGE_CACHE_SIZE;
  44                 inode->i_blocks = 0;
  45                 inode->i_mapping->a_ops = &hwgfs_aops;
  46                 inode->i_mapping->backing_dev_info = &hwgfs_backing_dev_info;
  47                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
  48                 switch (mode & S_IFMT) {
  49                 default:
  50                         init_special_inode(inode, mode, dev);
  51                         break;
  52                 case S_IFREG:
  53                         inode->i_op = &hwgfs_file_inode_operations;
  54                         inode->i_fop = &hwgfs_file_operations;
  55                         break;
  56                 case S_IFDIR:
  57                         inode->i_op = &hwgfs_dir_inode_operations;
  58                         inode->i_fop = &simple_dir_operations;
  59                         inode->i_nlink++;
  60                         break;
  61                 case S_IFLNK:
  62                         inode->i_op = &page_symlink_inode_operations;
  63                         break;
  64                 }
  65         }
  66         return inode;
  67 }
  68
  69 static int hwgfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
  70 {
  71         struct inode * inode = hwgfs_get_inode(dir->i_sb, mode, dev);
  72         int error = -ENOSPC;
  73
  74         if (inode) {
  75                 d_instantiate(dentry, inode);
  76                 dget(dentry);           /* Extra count - pin the dentry in core */
  77                 error = 0;
  78         }
  79         return error;
  80 }
  81
  82 static int hwgfs_mkdir(struct inode * dir, struct dentry * dentry, int mode)
  83 {
  84         return hwgfs_mknod(dir, dentry, mode | S_IFDIR, 0);
  85 }
  86
  87 static int hwgfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *unused)
  88 {
  89         return hwgfs_mknod(dir, dentry, mode | S_IFREG, 0);
  90 }
  91
  92 static int hwgfs_symlink(struct inode * dir, struct dentry *dentry, const char * symname)
  93 {
  94         struct inode *inode;
  95         int error = -ENOSPC;
  96
  97         inode = hwgfs_get_inode(dir->i_sb, S_IFLNK|S_IRWXUGO, 0);
  98         if (inode) {
  99                 int l = strlen(symname)+1;
 100                 error = page_symlink(inode, symname, l);
 101                 if (!error) {
 102                         d_instantiate(dentry, inode);
 103                         dget(dentry);
 104                 } else
 105                         iput(inode);
 106         }
 107         return error;
 108 }
 109
 110 static struct address_space_operations hwgfs_aops = {
 111         .readpage       = simple_readpage,
 112         .prepare_write  = simple_prepare_write,
 113         .commit_write   = simple_commit_write
 114 };
 115
 116 static struct file_operations hwgfs_file_operations = {
 117         .read           = generic_file_read,
 118         .write          = generic_file_write,
 119         .mmap           = generic_file_mmap,
 120         .fsync          = simple_sync_file,
 121         .sendfile       = generic_file_sendfile,
 122 };
 123
 124 static struct inode_operations hwgfs_file_inode_operations = {
 125         .getattr        = simple_getattr,
 126 };
 127
 128 static struct inode_operations hwgfs_dir_inode_operations = {
 129         .create         = hwgfs_create,
 130         .lookup         = simple_lookup,
 131         .link           = simple_link,
 132         .unlink         = simple_unlink,
 133         .symlink        = hwgfs_symlink,
 134         .mkdir          = hwgfs_mkdir,
 135         .rmdir          = simple_rmdir,
 136         .mknod          = hwgfs_mknod,
 137         .rename         = simple_rename,
 138 };
 139
 140 static struct super_operations hwgfs_ops = {
 141         .statfs         = simple_statfs,
 142         .drop_inode     = generic_delete_inode,
 143 };
 144
 145 static int hwgfs_fill_super(struct super_block * sb, void * data, int silent)
 146 {
 147         struct inode * inode;
 148         struct dentry * root;
 149
 150         sb->s_blocksize = PAGE_CACHE_SIZE;
 151         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 152         sb->s_magic = HWGFS_MAGIC;
 153         sb->s_op = &hwgfs_ops;
 154         inode = hwgfs_get_inode(sb, S_IFDIR | 0755, 0);
 155         if (!inode)
 156                 return -ENOMEM;
 157
 158         root = d_alloc_root(inode);
 159         if (!root) {
 160                 iput(inode);
 161                 return -ENOMEM;
 162         }
 163         sb->s_root = root;
 164         return 0;
 165 }
 166
 167 static struct super_block *hwgfs_get_sb(struct file_system_type *fs_type,
 168         int flags, const char *dev_name, void *data)
 169 {
 170         return get_sb_single(fs_type, flags, data, hwgfs_fill_super);
 171 }
 172
 173 static struct file_system_type hwgfs_fs_type = {
 174         .owner          = THIS_MODULE,
 175         .name           = "hwgfs",
 176         .get_sb         = hwgfs_get_sb,
 177         .kill_sb        = kill_litter_super,
 178 };
 179
 180 struct vfsmount *hwgfs_vfsmount;
 181
 182 int __init init_hwgfs_fs(void)
 183 {
 184         int error;
 185
 186         error = register_filesystem(&hwgfs_fs_type);
 187         if (error)
 188                 return error;
 189
 190         hwgfs_vfsmount = kern_mount(&hwgfs_fs_type);
 191         if (IS_ERR(hwgfs_vfsmount))
 192                 goto fail;
 193         return 0;
 194
 195 fail:
 196         unregister_filesystem(&hwgfs_fs_type);
 197         return PTR_ERR(hwgfs_vfsmount);
 198 }
 199
 200 static void __exit exit_hwgfs_fs(void)
 201 {
 202         unregister_filesystem(&hwgfs_fs_type);
 203 }
 204
 205 MODULE_LICENSE("GPL");
 206
 207 module_init(init_hwgfs_fs)
 208 module_exit(exit_hwgfs_fs)