fs/rcfs/dir.c

   1 /*
   2  * fs/rcfs/dir.c
   3  *
   4  * Copyright (C) Shailabh Nagar,  IBM Corp. 2004
   5  *               Vivek Kashyap,   IBM Corp. 2004
   6  *
   7  *
   8  * Directory operations for rcfs
   9  *
  10  * Latest version, more details at http://ckrm.sf.net
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2 of the License, or
  15  * (at your option) any later version.
  16  *
  17  */
  18
  19 /* Changes
  20  *
  21  * 08 Mar 2004
  22  *        Created.
  23  */
  24
  25 #include <linux/module.h>
  26 #include <linux/fs.h>
  27 #include <linux/namei.h>
  28 #include <linux/namespace.h>
  29 #include <linux/dcache.h>
  30 #include <linux/seq_file.h>
  31 #include <linux/pagemap.h>
  32 #include <linux/highmem.h>
  33 #include <linux/init.h>
  34 #include <linux/string.h>
  35 #include <linux/smp_lock.h>
  36 #include <linux/backing-dev.h>
  37 #include <linux/parser.h>
  38
  39 #include <asm/uaccess.h>
  40
  41 #include <linux/rcfs.h>
  42
  43 #define rcfs_positive(dentry)  ((dentry)->d_inode && !d_unhashed((dentry)))
  44
  45 int rcfs_empty(struct dentry *dentry)
  46 {
  47         struct dentry *child;
  48         int ret = 0;
  49
  50         spin_lock(&dcache_lock);
  51         list_for_each_entry(child, &dentry->d_subdirs, d_child)
  52             if (!rcfs_is_magic(child) && rcfs_positive(child))
  53                 goto out;
  54         ret = 1;
  55       out:
  56         spin_unlock(&dcache_lock);
  57         return ret;
  58 }
  59
  60 /* Directory inode operations */
  61
  62 int
  63 rcfs_create(struct inode *dir, struct dentry *dentry, int mode,
  64             struct nameidata *nd)
  65 {
  66         return rcfs_mknod(dir, dentry, mode | S_IFREG, 0);
  67 }
  68
  69 EXPORT_SYMBOL(rcfs_create);
  70
  71 /* Symlinks permitted ?? */
  72 int rcfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
  73 {
  74         struct inode *inode;
  75         int error = -ENOSPC;
  76
  77         inode = rcfs_get_inode(dir->i_sb, S_IFLNK | S_IRWXUGO, 0);
  78         if (inode) {
  79                 int l = strlen(symname) + 1;
  80                 error = page_symlink(inode, symname, l);
  81                 if (!error) {
  82                         if (dir->i_mode & S_ISGID)
  83                                 inode->i_gid = dir->i_gid;
  84                         d_instantiate(dentry, inode);
  85                         dget(dentry);
  86                 } else
  87                         iput(inode);
  88         }
  89         return error;
  90 }
  91
  92 EXPORT_SYMBOL(rcfs_symlink);
  93
  94 int rcfs_create_coredir(struct inode *dir, struct dentry *dentry)
  95 {
  96
  97         struct rcfs_inode_info *ripar, *ridir;
  98         int sz;
  99
 100         ripar = RCFS_I(dir);
 101         ridir = RCFS_I(dentry->d_inode);
 102
 103         // Inform RC's - do Core operations
 104         if (ckrm_is_core_valid(ripar->core)) {
 105                 sz = strlen(ripar->name) + strlen(dentry->d_name.name) + 2;
 106                 ridir->name = kmalloc(sz, GFP_KERNEL);
 107                 if (!ridir->name) {
 108                         return -ENOMEM;
 109                 }
 110                 snprintf(ridir->name, sz, "%s/%s", ripar->name,
 111                          dentry->d_name.name);
 112                 ridir->core = (*(ripar->core->classtype->alloc))
 113                     (ripar->core, ridir->name);
 114         } else {
 115                 printk(KERN_ERR "rcfs_mkdir: Invalid parent core %p\n",
 116                        ripar->core);
 117                 return -EINVAL;
 118         }
 119
 120         return 0;
 121 }
 122
 123 EXPORT_SYMBOL(rcfs_create_coredir);
 124
 125 int rcfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 126 {
 127
 128         int retval = 0;
 129         ckrm_classtype_t *clstype;
 130
 131 #if 0
 132         struct dentry *pd = list_entry(dir->i_dentry.next, struct dentry,
 133                                        d_alias);
 134         if ((!strcmp(pd->d_name.name, "/") &&
 135              !strcmp(dentry->d_name.name, "ce"))) {
 136                 // Call CE's mkdir if it has registered, else fail.
 137                 if (rcfs_eng_callbacks.mkdir) {
 138                         return (*rcfs_eng_callbacks.mkdir) (dir, dentry, mode);
 139                 } else {
 140                         return -EINVAL;
 141                 }
 142         }
 143 #endif
 144
 145         if (_rcfs_mknod(dir, dentry, mode | S_IFDIR, 0)) {
 146                 printk(KERN_ERR "rcfs_mkdir: error in _rcfs_mknod\n");
 147                 return retval;
 148         }
 149
 150         dir->i_nlink++;
 151
 152         // Inherit parent's ops since _rcfs_mknod assigns noperm ops
 153         dentry->d_inode->i_op = dir->i_op;
 154         dentry->d_inode->i_fop = dir->i_fop;
 155
 156         retval = rcfs_create_coredir(dir, dentry);
 157         if (retval) {
 158                 simple_rmdir(dir, dentry);
 159                 return retval;
 160                 // goto mkdir_err;
 161         }
 162         // create the default set of magic files
 163         clstype = (RCFS_I(dentry->d_inode))->core->classtype;
 164         rcfs_create_magic(dentry, &(((struct rcfs_magf *)clstype->mfdesc)[1]),
 165                           clstype->mfcount - 3);
 166
 167         return retval;
 168
 169 //mkdir_err:
 170         dir->i_nlink--;
 171         return retval;
 172 }
 173
 174 EXPORT_SYMBOL(rcfs_mkdir);
 175
 176 int rcfs_rmdir(struct inode *dir, struct dentry *dentry)
 177 {
 178         struct rcfs_inode_info *ri = RCFS_I(dentry->d_inode);
 179
 180 #if 0
 181         struct dentry *pd = list_entry(dir->i_dentry.next,
 182                                        struct dentry, d_alias);
 183         if ((!strcmp(pd->d_name.name, "/") &&
 184              !strcmp(dentry->d_name.name, "ce"))) {
 185                 // Call CE's mkdir if it has registered, else fail.
 186                 if (rcfs_eng_callbacks.rmdir) {
 187                         return (*rcfs_eng_callbacks.rmdir) (dir, dentry);
 188                 } else {
 189                         return simple_rmdir(dir, dentry);
 190                 }
 191         } else if ((!strcmp(pd->d_name.name, "/") &&
 192                     !strcmp(dentry->d_name.name, "network"))) {
 193                 return -EPERM;
 194         }
 195 #endif
 196
 197         if (!rcfs_empty(dentry)) {
 198                 printk(KERN_ERR "rcfs_rmdir: directory not empty\n");
 199                 return -ENOTEMPTY;
 200         }
 201         // Core class removal
 202
 203         if (ri->core == NULL) {
 204                 printk(KERN_ERR "rcfs_rmdir: core==NULL\n");
 205                 // likely a race condition
 206                 return 0;
 207         }
 208
 209         if ((*(ri->core->classtype->free)) (ri->core)) {
 210                 printk(KERN_ERR "rcfs_rmdir: ckrm_free_core_class failed\n");
 211                 goto out;
 212         }
 213         ri->core = NULL;        // just to be safe
 214
 215         // Clear magic files only after core successfully removed
 216         rcfs_clear_magic(dentry);
 217
 218         return simple_rmdir(dir, dentry);
 219
 220       out:
 221         return -EBUSY;
 222 }
 223
 224 EXPORT_SYMBOL(rcfs_rmdir);
 225
 226 int rcfs_unlink(struct inode *dir, struct dentry *dentry)
 227 {
 228         // -ENOENT and not -ENOPERM to allow rm -rf to work despite
 229         // magic files being present
 230         return -ENOENT;
 231 }
 232
 233 EXPORT_SYMBOL(rcfs_unlink);
 234
 235 // rename is allowed on directories only
 236 int
 237 rcfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 238             struct inode *new_dir, struct dentry *new_dentry)
 239 {
 240         if (S_ISDIR(old_dentry->d_inode->i_mode))
 241                 return simple_rename(old_dir, old_dentry, new_dir, new_dentry);
 242         else
 243                 return -EINVAL;
 244 }
 245
 246 EXPORT_SYMBOL(rcfs_rename);
 247
 248 struct inode_operations rcfs_dir_inode_operations = {
 249         .create = rcfs_create,
 250         .lookup = simple_lookup,
 251         .link = simple_link,
 252         .unlink = rcfs_unlink,
 253         .symlink = rcfs_symlink,
 254         .mkdir = rcfs_mkdir,
 255         .rmdir = rcfs_rmdir,
 256         .mknod = rcfs_mknod,
 257         .rename = rcfs_rename,
 258 };
 259
 260 int
 261 rcfs_root_create(struct inode *dir, struct dentry *dentry, int mode,
 262                  struct nameidata *nd)
 263 {
 264         return -EPERM;
 265 }
 266
 267 int
 268 rcfs_root_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
 269 {
 270         return -EPERM;
 271 }
 272
 273 int rcfs_root_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 274 {
 275         return -EPERM;
 276 }
 277
 278 int rcfs_root_rmdir(struct inode *dir, struct dentry *dentry)
 279 {
 280         return -EPERM;
 281 }
 282
 283 int rcfs_root_unlink(struct inode *dir, struct dentry *dentry)
 284 {
 285         return -EPERM;
 286 }
 287
 288 int
 289 rcfs_root_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
 290 {
 291         return -EPERM;
 292 }
 293
 294 int
 295 rcfs_root_rename(struct inode *old_dir, struct dentry *old_dentry,
 296                  struct inode *new_dir, struct dentry *new_dentry)
 297 {
 298         return -EPERM;
 299 }
 300
 301 struct inode_operations rcfs_rootdir_inode_operations = {
 302         .create = rcfs_root_create,
 303         .lookup = simple_lookup,
 304         .link = simple_link,
 305         .unlink = rcfs_root_unlink,
 306         .symlink = rcfs_root_symlink,
 307         .mkdir = rcfs_root_mkdir,
 308         .rmdir = rcfs_root_rmdir,
 309         .mknod = rcfs_root_mknod,
 310         .rename = rcfs_root_rename,
 311 };