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
  26 #include <linux/module.h>
  27 #include <linux/fs.h>
  28 #include <linux/namei.h>
  29 #include <asm/namei.h>
  30 #include <linux/namespace.h>
  31 #include <linux/dcache.h>
  32 #include <linux/seq_file.h>
  33 #include <linux/pagemap.h>
  34 #include <linux/highmem.h>
  35 #include <linux/init.h>
  36 #include <linux/string.h>
  37 #include <linux/smp_lock.h>
  38 #include <linux/backing-dev.h>
  39 #include <linux/parser.h>
  40
  41 #include <asm/uaccess.h>
  42
  43 #include <linux/rcfs.h>
  44
  45
  46
  47 #define rcfs_positive(dentry)  ((dentry)->d_inode && !d_unhashed((dentry)))
  48
  49 int rcfs_empty(struct dentry *dentry)
  50 {
  51         struct dentry *child;
  52         int ret = 0;
  53
  54         spin_lock(&dcache_lock);
  55         list_for_each_entry(child, &dentry->d_subdirs, d_child)
  56                 if (!rcfs_is_magic(child) && rcfs_positive(child))
  57                         goto out;
  58         ret = 1;
  59 out:
  60         spin_unlock(&dcache_lock);
  61         return ret;
  62 }
  63
  64
  65
  66
  67 /* Directory inode operations */
  68
  69
  70 int
  71 rcfs_create(struct inode *dir, struct dentry *dentry, int mode,
  72             struct nameidata *nd)
  73 {
  74         return rcfs_mknod(dir, dentry, mode | S_IFREG, 0);
  75 }
  76 EXPORT_SYMBOL(rcfs_create);
  77
  78
  79 /* Symlinks permitted ?? */
  80 int
  81 rcfs_symlink(struct inode * dir, struct dentry *dentry, const char * symname)
  82 {
  83         struct inode *inode;
  84         int error = -ENOSPC;
  85
  86         inode = rcfs_get_inode(dir->i_sb, S_IFLNK|S_IRWXUGO, 0);
  87         if (inode) {
  88                 int l = strlen(symname)+1;
  89                 error = page_symlink(inode, symname, l);
  90                 if (!error) {
  91                         if (dir->i_mode & S_ISGID)
  92                                 inode->i_gid = dir->i_gid;
  93                         d_instantiate(dentry, inode);
  94                         dget(dentry);
  95                 } else
  96                         iput(inode);
  97         }
  98         return error;
  99 }
 100 EXPORT_SYMBOL(rcfs_symlink);
 101
 102 int
 103 rcfs_create_coredir(struct inode *dir, struct dentry *dentry)
 104 {
 105
 106         struct rcfs_inode_info *ripar, *ridir;
 107         int sz;
 108
 109         ripar = RCFS_I(dir);
 110         ridir = RCFS_I(dentry->d_inode);
 111
 112         // Inform RC's - do Core operations
 113         if (ckrm_is_core_valid(ripar->core)) {
 114                 sz = strlen(ripar->name) + strlen(dentry->d_name.name) + 2 ;
 115                 ridir->name = kmalloc(sz, GFP_KERNEL);
 116                 if (!ridir->name) {
 117                         return -ENOMEM;
 118                 }
 119                 snprintf(ridir->name, sz,"%s/%s", ripar->name,
 120                          dentry->d_name.name);
 121                 ridir->core = (*(ripar->core->classtype->alloc))
 122                         (ripar->core,ridir->name);
 123         }
 124         else {
 125                 printk(KERN_ERR "rcfs_mkdir: Invalid parent core %p\n",
 126                        ripar->core);
 127                 return -EINVAL;
 128         }
 129
 130         return 0;
 131 }
 132 EXPORT_SYMBOL(rcfs_create_coredir);
 133
 134
 135 int
 136 rcfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 137 {
 138
 139         int retval = 0;
 140         ckrm_classtype_t *clstype;
 141
 142 #if 0
 143         struct dentry *pd = list_entry(dir->i_dentry.next, struct dentry,
 144                                                         d_alias);
 145         if ((!strcmp(pd->d_name.name, "/") &&
 146              !strcmp(dentry->d_name.name, "ce"))) {
 147                 // Call CE's mkdir if it has registered, else fail.
 148                 if (rcfs_eng_callbacks.mkdir) {
 149                         return (*rcfs_eng_callbacks.mkdir)(dir, dentry, mode);
 150                 } else {
 151                         return -EINVAL;
 152                 }
 153         }
 154 #endif
 155
 156         if (_rcfs_mknod(dir, dentry, mode | S_IFDIR, 0)) {
 157                 printk(KERN_ERR "rcfs_mkdir: error in _rcfs_mknod\n");
 158                 return retval;
 159         }
 160
 161         dir->i_nlink++;
 162
 163         // Inherit parent's ops since _rcfs_mknod assigns noperm ops
 164         dentry->d_inode->i_op = dir->i_op;
 165         dentry->d_inode->i_fop = dir->i_fop;
 166
 167
 168         retval = rcfs_create_coredir(dir, dentry);
 169         if (retval) {
 170                 simple_rmdir(dir,dentry);
 171                 return retval;
 172                 // goto mkdir_err;
 173         }
 174
 175         // create the default set of magic files
 176         clstype = (RCFS_I(dentry->d_inode))->core->classtype;
 177         rcfs_create_magic(dentry, &(((struct rcfs_magf*)clstype->mfdesc)[1]),
 178                           clstype->mfcount-1);
 179
 180         return retval;
 181
 182 //mkdir_err:
 183         dir->i_nlink--;
 184         return retval;
 185 }
 186 EXPORT_SYMBOL(rcfs_mkdir);
 187
 188
 189 int
 190 rcfs_rmdir(struct inode * dir, struct dentry * dentry)
 191 {
 192         struct rcfs_inode_info *ri = RCFS_I(dentry->d_inode);
 193
 194 #if 0
 195         struct dentry *pd = list_entry(dir->i_dentry.next,
 196                                        struct dentry, d_alias);
 197         if ((!strcmp(pd->d_name.name, "/") &&
 198              !strcmp(dentry->d_name.name, "ce"))) {
 199                 // Call CE's mkdir if it has registered, else fail.
 200                 if (rcfs_eng_callbacks.rmdir) {
 201                         return (*rcfs_eng_callbacks.rmdir)(dir, dentry);
 202                 } else {
 203                         return simple_rmdir(dir, dentry);
 204                 }
 205         }
 206         else if ((!strcmp(pd->d_name.name, "/") &&
 207                   !strcmp(dentry->d_name.name, "network"))) {
 208                 return -EPERM;
 209         }
 210 #endif
 211
 212         if (!rcfs_empty(dentry)) {
 213                 printk(KERN_ERR "rcfs_rmdir: directory not empty\n");
 214                 goto out;
 215         }
 216
 217         // Core class removal
 218
 219         if (ri->core == NULL) {
 220                 printk(KERN_ERR "rcfs_rmdir: core==NULL\n");
 221                 // likely a race condition
 222                 return 0;
 223         }
 224
 225         if ((*(ri->core->classtype->free))(ri->core)) {
 226                 printk(KERN_ERR "rcfs_rmdir: ckrm_free_core_class failed\n");
 227                 goto out;
 228         }
 229         ri->core = NULL ; // just to be safe
 230
 231         // Clear magic files only after core successfully removed
 232         rcfs_clear_magic(dentry);
 233
 234         return simple_rmdir(dir, dentry);
 235
 236 out:
 237         return -EBUSY;
 238 }
 239 EXPORT_SYMBOL(rcfs_rmdir);
 240
 241
 242 int
 243 rcfs_unlink(struct inode *dir, struct dentry *dentry)
 244 {
 245         // -ENOENT and not -ENOPERM to allow rm -rf to work despite
 246         // magic files being present
 247         return -ENOENT;
 248 }
 249 EXPORT_SYMBOL(rcfs_unlink);
 250
 251 // rename is allowed on directories only
 252 int
 253 rcfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 254                 struct inode *new_dir, struct dentry *new_dentry)
 255 {
 256         if (S_ISDIR(old_dentry->d_inode->i_mode))
 257                 return simple_rename(old_dir, old_dentry, new_dir, new_dentry);
 258         else
 259                 return -EINVAL;
 260 }
 261 EXPORT_SYMBOL(rcfs_rename);
 262
 263
 264 struct inode_operations rcfs_dir_inode_operations = {
 265         .create         = rcfs_create,
 266         .lookup         = simple_lookup,
 267         .link           = simple_link,
 268         .unlink         = rcfs_unlink,
 269         .symlink        = rcfs_symlink,
 270         .mkdir          = rcfs_mkdir,
 271         .rmdir          = rcfs_rmdir,
 272         .mknod          = rcfs_mknod,
 273         .rename         = rcfs_rename,
 274 };
 275
 276
 277
 278
 279
 280 int
 281 rcfs_root_create(struct inode *dir, struct dentry *dentry, int mode,
 282                  struct nameidata *nd)
 283 {
 284         return -EPERM;
 285 }
 286
 287
 288 int
 289 rcfs_root_symlink(struct inode * dir, struct dentry *dentry,
 290                   const char * symname)
 291 {
 292         return -EPERM;
 293 }
 294
 295 int
 296 rcfs_root_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 297 {
 298         return -EPERM;
 299 }
 300
 301 int
 302 rcfs_root_rmdir(struct inode * dir, struct dentry * dentry)
 303 {
 304         return -EPERM;
 305 }
 306
 307 int
 308 rcfs_root_unlink(struct inode *dir, struct dentry *dentry)
 309 {
 310         return -EPERM;
 311 }
 312
 313 int
 314 rcfs_root_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
 315 {
 316         return -EPERM;
 317 }
 318
 319 int
 320 rcfs_root_rename(struct inode *old_dir, struct dentry *old_dentry,
 321                 struct inode *new_dir, struct dentry *new_dentry)
 322 {
 323         return -EPERM;
 324 }
 325
 326 struct inode_operations rcfs_rootdir_inode_operations = {
 327         .create         = rcfs_root_create,
 328         .lookup         = simple_lookup,
 329         .link           = simple_link,
 330         .unlink         = rcfs_root_unlink,
 331         .symlink        = rcfs_root_symlink,
 332         .mkdir          = rcfs_root_mkdir,
 333         .rmdir          = rcfs_root_rmdir,
 334         .mknod          = rcfs_root_mknod,
 335         .rename         = rcfs_root_rename,
 336 };