prepare for the transition to linux 2.6.22 - make it possible to override the kernel...

[openwrt/openwrt.git] / target / linux / generic-2.6 / patches-2.6.22 / 209-mini_fo.patch

diff -urN linux-2.6.21.1.old/fs/Kconfig linux-2.6.21.1.dev/fs/Kconfig
--- linux-2.6.21.1.old/fs/Kconfig       2007-05-26 19:03:45.497714200 +0200
+++ linux-2.6.21.1.dev/fs/Kconfig       2007-05-26 21:01:26.154331240 +0200
@@ -461,6 +461,9 @@
          This option will enlarge your kernel, but it allows debugging of
          ocfs2 filesystem issues.
 
+config MINI_FO
+       tristate "Mini fanout overlay filesystem"
+
 config MINIX_FS
        tristate "Minix fs support"
        help
diff -urN linux-2.6.21.1.old/fs/Makefile linux-2.6.21.1.dev/fs/Makefile
--- linux-2.6.21.1.old/fs/Makefile      2007-05-26 19:03:45.497714200 +0200
+++ linux-2.6.21.1.dev/fs/Makefile      2007-05-26 21:01:26.160330328 +0200
@@ -76,6 +76,7 @@
 obj-$(CONFIG_RAMFS)            += ramfs/
 obj-$(CONFIG_HUGETLBFS)                += hugetlbfs/
 obj-$(CONFIG_CODA_FS)          += coda/
+obj-$(CONFIG_MINI_FO)          += mini_fo/
 obj-$(CONFIG_MINIX_FS)         += minix/
 obj-$(CONFIG_FAT_FS)           += fat/
 obj-$(CONFIG_MSDOS_FS)         += msdos/
diff -urN linux-2.6.21.1.old/fs/mini_fo/aux.c linux-2.6.21.1.dev/fs/mini_fo/aux.c
--- linux-2.6.21.1.old/fs/mini_fo/aux.c 1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.21.1.dev/fs/mini_fo/aux.c 2007-05-26 21:01:26.160330328 +0200
@@ -0,0 +1,580 @@
+/*
+ * Copyright (c) 1997-2003 Erez Zadok
+ * Copyright (c) 2001-2003 Stony Brook University
+ *
+ * For specific licensing information, see the COPYING file distributed with
+ * this package, or get one from ftp://ftp.filesystems.org/pub/fist/COPYING.
+ *
+ * This Copyright notice must be kept intact and distributed with all
+ * fistgen sources INCLUDING sources generated by fistgen.
+ */
+/*
+ * Copyright (C) 2004, 2005 Markus Klotzbuecher <mk@creamnet.de>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+/*
+ *  $Id$
+ */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include "fist.h"
+#include "mini_fo.h"
+
+/* check if file exists in storage  */
+int exists_in_storage(dentry_t *dentry)
+{
+       check_mini_fo_dentry(dentry);
+       if(dtost(dentry) == MODIFIED || dtost(dentry) == CREATED || dtost(dentry) == DEL_REWRITTEN)
+               return 1;
+       return 0;       
+}
+
+/* check if dentry is in an existing state */
+int is_mini_fo_existant(dentry_t *dentry) 
+{
+       check_mini_fo_dentry(dentry);
+
+       if(dtost(dentry) == DELETED || dtost(dentry) == NON_EXISTANT)
+               return 0;
+       else
+               return 1;
+}
+
+/* 
+ * This function will create a negative storage dentry for 
+ * dentry, what is required for many create like options.
+ * It will create the storage structure if necessary.
+ */
+int get_neg_sto_dentry(dentry_t *dentry) 
+{
+       int err = 0;
+       unsigned int len;
+       const unsigned char *name;
+
+       if(!dentry ||
+          !dtopd(dentry) ||
+          !(dtost(dentry) == UNMODIFIED ||
+            dtost(dentry) == NON_EXISTANT ||
+            dtost(dentry) == DELETED)) {
+               printk(KERN_CRIT "mini_fo: get_neg_sto_dentry: invalid dentry passed.\n");
+               err = -1;
+               goto out;
+       }
+       /* Have we got a neg. dentry already? */
+       if(dtohd2(dentry)) {
+               err = 0;
+               goto out;
+       }
+       if(dtost(dentry->d_parent) == UNMODIFIED) {
+               /* build sto struct */
+               err = build_sto_structure(dentry->d_parent->d_parent, dentry->d_parent);
+               if(err || 
+                  dtost(dentry->d_parent) != MODIFIED) {
+                       printk(KERN_CRIT "mini_fo: get_neg_sto_dentry: ERROR building sto structure.\n");
+                       err = -1;
+                       goto out;
+               }               
+       }
+
+       len = dentry->d_name.len;
+       name = dentry->d_name.name;
+        
+       dtohd2(dentry) = 
+               lookup_one_len(name, dtohd2(dentry->d_parent), len);
+
+ out:
+       return err;
+}
+
+int check_mini_fo_dentry(dentry_t *dentry)
+{
+       ASSERT(dentry != NULL);
+       ASSERT(dtopd(dentry) != NULL);
+       ASSERT((dtohd(dentry) != NULL) || (dtohd2(dentry) != NULL));
+              
+/*     if(dtost(dentry) == MODIFIED) { */
+/*             ASSERT(dentry->d_inode != NULL); */
+/*             ASSERT(dtohd(dentry) != NULL); */
+/*             ASSERT(dtohd(dentry)->d_inode != NULL); */
+/*             ASSERT(dtohd2(dentry) != NULL); */
+/*             ASSERT(dtohd2(dentry)->d_inode != NULL); */
+/*     } */
+/*     else if(dtost(dentry) == UNMODIFIED) { */
+/*             ASSERT(dentry->d_inode != NULL); */
+/*             ASSERT( */
+/*     } */
+       return 0;              
+}
+
+int check_mini_fo_file(file_t *file)
+{
+       ASSERT(file != NULL);
+       ASSERT(ftopd(file) != NULL);
+       ASSERT(file->f_dentry != NULL);
+       
+       /* violent checking, check depending of state and type 
+        *      if(S_ISDIR(file->f_dentry->d_inode->i_mode)) {}
+        */
+       ASSERT((ftohf(file) != NULL) || (ftohf2(file) != NULL));
+       return 0;
+}
+
+int check_mini_fo_inode(inode_t *inode)
+{
+       ASSERT(inode != NULL);
+       ASSERT(itopd(inode) != NULL);
+       ASSERT((itohi(inode) != NULL) || (itohi2(inode) != NULL));
+       return 0;
+}
+
+/* 
+ * will walk a base path as provided by get_mini_fo_bpath and return
+ * the (hopefully ;-) ) positive dentry of the renamed base dir.
+ *
+ * This does some work of path_init.
+ */
+dentry_t *bpath_walk(super_block_t *sb, char *bpath) 
+{
+       int err;
+       struct nameidata nd;
+
+       /* be paranoid */
+       if(!bpath || bpath[0] != '/') {
+               printk(KERN_CRIT "mini_fo: bpath_walk: Invalid string.\n");
+               return NULL;
+       }
+       if(!sb || !stopd(sb)) {
+               printk(KERN_CRIT "mini_fo: bpath_walk: Invalid sb.\n");
+               return NULL;
+       }
+       
+       /* setup nd as path_init does */
+       nd.last_type = LAST_ROOT; /* if there are only slashes... */
+       nd.flags = LOOKUP_FOLLOW;
+       /* fix this: how do I reach this lock? 
+        * read_lock(&current->fs->lock); */
+       nd.mnt = mntget(stopd(sb)->hidden_mnt);
+       nd.dentry = dget(stopd(sb)->base_dir_dentry);
+       /* read_unlock(&current->fs->lock); */
+       
+       err = path_walk(bpath+1, &nd);
+
+       /* validate */
+       if (err || !nd.dentry || !nd.dentry->d_inode) {
+               printk(KERN_CRIT "mini_fo: bpath_walk: path_walk failed.\n");
+               return NULL;
+       }
+       return nd.dentry;
+}
+
+
+/* returns the full path of the basefile incl. its name */
+int get_mini_fo_bpath(dentry_t *dentry, char **bpath, int *bpath_len)
+{
+       char *buf_walker;
+       int len = 0;
+       dentry_t *sky_walker;
+       
+       if(!dentry || !dtohd(dentry)) {
+               printk(KERN_CRIT "mini_fo: get_mini_fo_bpath: invalid dentry passed.\n");
+               return -1;
+       }
+       sky_walker = dtohd(dentry);
+
+       do {
+               len += sky_walker->d_name.len + 1 ; /* 1 for '/' */
+               sky_walker = sky_walker->d_parent;
+       } while(sky_walker != stopd(dentry->d_inode->i_sb)->base_dir_dentry);
+
+       /* 1 to oil the loop */
+       *bpath = (char*)  kmalloc(len + 1, GFP_KERNEL);
+       if(!*bpath) {
+               printk(KERN_CRIT "mini_fo: get_mini_fo_bpath: out of mem.\n");
+               return -1;
+       }
+       buf_walker = *bpath+len; /* put it on last char */
+       *buf_walker = '\n';
+       sky_walker = dtohd(dentry);
+       
+       do {
+               buf_walker -= sky_walker->d_name.len;
+               strncpy(buf_walker, 
+                       sky_walker->d_name.name, 
+                       sky_walker->d_name.len);
+               *(--buf_walker) = '/';
+               sky_walker = sky_walker->d_parent;
+       } while(sky_walker != stopd(dentry->d_inode->i_sb)->base_dir_dentry);
+
+       /* bpath_len doesn't count newline! */
+       *bpath_len = len;
+       return 0;
+}
+
+int mini_fo_cp_cont(dentry_t *tgt_dentry, struct vfsmount *tgt_mnt,
+                   dentry_t *src_dentry, struct vfsmount *src_mnt)
+{
+       void *buf;
+       mm_segment_t old_fs;
+       file_t *tgt_file;
+       file_t *src_file;
+       int bytes, len, tmp, err;
+       err = 0;
+
+       if(!(tgt_dentry->d_inode && src_dentry->d_inode)) {
+               printk(KERN_CRIT "mini_fo_cp_cont: ERROR, neg. dentry passed.\n");
+               err = -EINVAL;
+               goto out;
+       }
+
+       dget(tgt_dentry);
+       dget(src_dentry);
+       mntget(tgt_mnt);
+       mntget(src_mnt);
+
+       /* open file write only */
+       tgt_file = dentry_open(tgt_dentry, tgt_mnt, 0x1);
+       if(!tgt_file || IS_ERR(tgt_file)) {
+               printk(KERN_CRIT "mini_fo_cp_cont: ERROR opening target file.\n");
+               err = PTR_ERR(tgt_file);
+               goto out_err;
+       }
+
+       /* open file read only */
+       src_file = dentry_open(src_dentry, src_mnt, 0x0);
+       if(!src_file || IS_ERR(src_file)) {
+               printk(KERN_CRIT "mini_fo_cp_cont: ERROR opening source file.\n");
+               err = PTR_ERR(src_file);
+
+               /* close target file */
+               fput(tgt_file);
+               goto out_err;
+       }
+
+       /* check if the filesystem(s) support read respective write */
+       if(!src_file->f_op->read || !tgt_file->f_op->write) {
+               printk(KERN_CRIT "mini_fo_cp_cont: ERROR, no fs read or write support.\n");
+               err = -EPERM;
+               goto out_close;
+       }
+
+       /* allocate a page for transfering the data */
+       buf = (void *) __get_free_page(GFP_KERNEL);
+       if(!buf) {
+               printk(KERN_CRIT "mini_fo_cp_cont: ERROR, out of kernel mem.\n");
+               goto out_err;
+       }
+
+       tgt_file->f_pos = 0;
+       src_file->f_pos = 0;
+
+       old_fs = get_fs();
+       set_fs(KERNEL_DS);
+
+       /* Doing this I assume that a read operation will return a full
+        * buffer while there is still data to read, and a less than
+        * full buffer when all data has been read.
+        */
+       bytes = len = PAGE_SIZE;
+       while(bytes == len) {
+               bytes = src_file->f_op->read(src_file, buf, len, 
+                                            &src_file->f_pos);
+               tmp = tgt_file->f_op->write(tgt_file, buf, bytes, 
+                                           &tgt_file->f_pos);
+               if(tmp != bytes) {
+                       printk(KERN_CRIT "mini_fo_cp_cont: ERROR writing.\n");
+                       goto out_close_unset;
+               }
+       }
+
+       free_page((unsigned long) buf);
+       set_fs(old_fs);
+       fput(tgt_file);
+       fput(src_file);
+       goto out;
+
+ out_close_unset:
+       free_page((unsigned long) buf);
+       set_fs(old_fs);
+
+ out_close:
+       fput(tgt_file);
+       fput(src_file);
+
+ out_err:
+       dput(tgt_dentry);
+       dput(src_dentry);
+
+       /* mk: not sure if this need to be done */
+       mntput(tgt_mnt);
+       mntput(src_mnt);
+
+ out:
+       return err;
+}
+
+/* mk:
+ * ndl (no-duplicate list) stuff
+ * This is used in mini_fo_readdir, to save the storage directory contents
+ * and later when reading base, match them against the list in order
+ * to avoid duplicates.
+ */
+
+/* add a file specified by name and len to the ndl
+ * Return values: 0 on success, <0 on failure.
+ */
+int ndl_add_entry(struct readdir_data *rd, const char *name, int len)
+{
+       struct ndl_entry *tmp_entry;
+
+       tmp_entry = (struct ndl_entry *) 
+               kmalloc(sizeof(struct ndl_entry), GFP_KERNEL);
+       if(!tmp_entry) {
+                printk(KERN_CRIT "mini_fo: ndl_add_entry: out of mem.\n");
+                return -ENOMEM;
+        }
+        tmp_entry->name = (char*) kmalloc(len, GFP_KERNEL);
+        if(!tmp_entry->name) {
+                printk(KERN_CRIT "mini_fo: ndl_add_entry: out of mem.\n");
+                return -ENOMEM;
+        }
+       strncpy(tmp_entry->name, name, len);
+        tmp_entry->len = len;
+
+        list_add(&tmp_entry->list, &rd->ndl_list);
+        rd->ndl_size++;
+        return 0;
+}
+
+/* delete all list entries and free memory */
+void ndl_put_list(struct readdir_data *rd)
+{
+       struct list_head *tmp;
+       struct ndl_entry *tmp_entry;
+
+       if(rd->ndl_size <= 0)
+               return;
+       while(!list_empty(&rd->ndl_list)) {
+               tmp = rd->ndl_list.next;
+                list_del(tmp);
+                tmp_entry = list_entry(tmp, struct ndl_entry, list);
+               kfree(tmp_entry->name);
+                kfree(tmp_entry);
+        }
+       rd->ndl_size = 0;
+}
+
+/* Check if a file specified by name and len is in the ndl
+ * Return value: 0 if not in list, 1 if file is found in ndl.
+ */
+int ndl_check_entry(struct readdir_data *rd, const char *name, int len)
+{
+       struct list_head *tmp;
+       struct ndl_entry *tmp_entry;
+
+       if(rd->ndl_size <= 0)
+               return 0;
+
+       list_for_each(tmp, &rd->ndl_list) {
+                tmp_entry = list_entry(tmp, struct ndl_entry, list);
+                if(tmp_entry->len != len)
+                        continue;
+                if(!strncmp(tmp_entry->name, name, len))
+                        return 1;
+        }
+        return 0;
+}
+
+/* mk:
+ * Recursive function to create corresponding directorys in the storage fs.
+ * The function will build the storage directorys up to dentry.
+ */
+int build_sto_structure(dentry_t *dir, dentry_t *dentry)
+{
+       int err;
+       dentry_t *hidden_sto_dentry;
+       dentry_t *hidden_sto_dir_dentry;
+
+       if(dentry->d_parent != dir) {
+               printk(KERN_CRIT "mini_fo: build_sto_structure: invalid parameter or meta data corruption [1].\n");
+               return 1;
+       }
+
+               if(dtost(dir) != MODIFIED) {
+               err = build_sto_structure(dir->d_parent, dentry->d_parent);
+               if(err)
+                       return err;
+       }
+
+       /* ok, coming back again. */
+       check_mini_fo_dentry(dentry);
+       hidden_sto_dentry = dtohd2(dentry);
+
+       if(!hidden_sto_dentry) {
+               /*
+                * This is the case after creating the first 
+                * hidden_sto_dentry.
+                * After one negative storage_dentry, all pointers to 
+                * hidden_storage dentries are set to NULL. We need to
+                * create the negative dentry before we create the storage
+                * file.
+                */
+               unsigned int len;
+               const unsigned char *name;
+               len = dtohd(dentry)->d_name.len;
+               name = dtohd(dentry)->d_name.name;
+               hidden_sto_dentry = lookup_one_len(name, dtohd2(dir), len);
+               dtohd2(dentry) = hidden_sto_dentry;
+       }
+
+       /* was: hidden_sto_dir_dentry = lock_parent(hidden_sto_dentry); */
+       hidden_sto_dir_dentry = dget(hidden_sto_dentry->d_parent);
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
+       mutex_lock(&hidden_sto_dir_dentry->d_inode->i_mutex);
+#else
+       down(&hidden_sto_dir_dentry->d_inode->i_sem);
+#endif
+       /* lets be safe */
+       if(dtohd2(dir) != hidden_sto_dir_dentry) {
+               printk(KERN_CRIT "mini_fo: build_sto_structure: invalid parameter or meta data corruption [2].\n");
+               return 1;
+       }
+
+       /* check for errors in lock_parent */
+       err = PTR_ERR(hidden_sto_dir_dentry);
+       if(IS_ERR(hidden_sto_dir_dentry)) {
+               printk(KERN_CRIT "mini_fo: build_sto_structure: lock_parent failed.\n");
+               return err;
+       }
+
+       err = vfs_mkdir(hidden_sto_dir_dentry->d_inode,
+                       hidden_sto_dentry,
+                       dir->d_inode->i_mode);
+
+       if(err) {
+               printk(KERN_CRIT "mini_fo: build_sto_structure: failed to create storage dir [1].\n");
+               /* was: unlock_dir(dir); */
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
+               mutex_unlock(&dir->d_inode->i_mutex);
+#else
+               up(&dir->d_inode->i_sem);
+#endif
+               dput(dir);
+               return err;
+       }
+       
+       /* everything ok! */
+       if(!dtohd2(dentry)->d_inode) {
+               printk(KERN_CRIT "mini_fo: build_sto_structure: failed to create storage dir [2].\n");
+               /* was: unlock_dir(dir); */
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
+               mutex_unlock(&dir->d_inode->i_mutex);
+#else
+               up(&dir->d_inode->i_sem);
+#endif
+               dput(dir);
+               return 1;
+       }
+
+       /* interpose the new inode and set new state */
+       itohi2(dentry->d_inode) = igrab(dtohd2(dentry)->d_inode);
+       dtopd(dentry)->state = MODIFIED;
+
+       /* initalize the wol list */
+       itopd(dentry->d_inode)->deleted_list_size = -1;
+       itopd(dentry->d_inode)->renamed_list_size = -1;
+       meta_build_lists(dentry);
+       
+       fist_copy_attr_all(dentry->d_inode, itohi2(dentry->d_inode));
+       fist_copy_attr_timesizes(dir->d_inode, 
+                                hidden_sto_dir_dentry->d_inode);
+       dir->d_inode->i_nlink++;
+       /* was: unlock_dir(hidden_sto_dir_dentry); */
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
+       mutex_unlock(&hidden_sto_dir_dentry->d_inode->i_mutex);
+#else
+       up(&hidden_sto_dir_dentry->d_inode->i_sem);
+#endif
+       dput(hidden_sto_dir_dentry);
+       return 0;
+}
+
+
+#if 0 /* unused */
+
+/*
+ * Read "len" bytes from "filename" into "buf".
+ * "buf" is in kernel space.
+ */
+int
+mini_fo_read_file(const char *filename, void *buf, int len)
+{
+    file_t *filp;
+    mm_segment_t oldfs;
+    int bytes;
+    /* Chroot? Maybe NULL isn't right here */
+    filp = filp_open(filename, O_RDONLY, 0);
+    if (!filp || IS_ERR(filp)) {
+       printk("mini_fo_read_file err %d\n", (int) PTR_ERR(filp));
+       return -1;  /* or do something else */
+    }
+
+    if (!filp->f_op->read)
+       return -2;  /* file(system) doesn't allow reads */
+
+    /* now read len bytes from offset 0 */
+    filp->f_pos = 0;           /* start offset */
+    oldfs = get_fs();
+    set_fs(KERNEL_DS);
+    bytes = filp->f_op->read(filp, buf, len, &filp->f_pos);
+    set_fs(oldfs);
+
+    /* close the file */
+    fput(filp);
+
+    return bytes;
+}
+
+
+
+/*
+ * Write "len" bytes from "buf" to "filename"
+ * "buf" is in kernel space.
+ */
+int
+mini_fo_write_file(const char *filename, void *buf, int len)
+{
+    file_t *filp;
+    mm_segment_t oldfs;
+    int bytes;
+                               /* Chroot? Maybe NULL isn't right here */
+    filp = filp_open(filename, O_RDWR|O_CREAT, 0640);
+    if (!filp || IS_ERR(filp)) {
+       printk("mini_fo_write_file err %d\n", (int) PTR_ERR(filp));
+       return -1;  /* or do something else */
+    }
+
+    if (!filp->f_op->write)
+       return -2;  /* file(system) doesn't allow writes */
+
+    /* now write len bytes from offset 0 */
+    filp->f_pos = 0;           /* start offset */
+    oldfs = get_fs();
+    set_fs(KERNEL_DS);
+    bytes = filp->f_op->write(filp, buf, len, &filp->f_pos);
+    set_fs(oldfs);
+
+    /* close the file */
+    fput(filp);
+
+    return bytes;
+}
+
+#endif /* unused */
+
diff -urN linux-2.6.21.1.old/fs/mini_fo/ChangeLog linux-2.6.21.1.dev/fs/mini_fo/ChangeLog
--- linux-2.6.21.1.old/fs/mini_fo/ChangeLog     1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.21.1.dev/fs/mini_fo/ChangeLog     2007-05-26 21:01:26.161330176 +0200
@@ -0,0 +1,281 @@
+2006-01-24  Markus Klotzbuecher  <mk@mary.denx.de>
+
+       * Add tons of ugly ifdefs to Ed L. Cashin's mutex patch to
+          retain backwards compatibility.
+       
+2006-01-24  Ed L. Cashin <ecashin@coraid.com>
+
+       * Support for the new mutex infrastructure
+       (7892f2f48d165a34b0b8130c8a195dfd807b8cb6)
+
+2005-10-15  Markus Klotzbuecher  <mk@localhost.localdomain>
+
+       * Bugfix for a serious memory leak in mini_fo_follow_link.
+
+2005-09-21  Markus Klotzbuecher  <mk@mary>
+
+       * new release 0.6.1
+
+       * fix of a compiler warning due to changes in 2.6.13
+
+2005-09-21  Klaus Wenninger  <klaus.wenninger@siemens.com>
+
+       * file.c: readdir: fix for a bug that caused directory entries
+          to show up twice when using storage filesystems such as
+          minixfs or pramfs.
+
+2005-06-30  Eric Lammerts <eric@lammerts.org>
+
+       * fix for an oops when overwriting a binary thats beeing
+          executed.
+
+2005-06-09    <mk@mary>
+
+       * Renamed overlay to mini_fo-overlay.
+
+       * Added mini_fo-merge script to allow merging of storage and base
+       after making modifications.
+
+2005-05-22  root  <mk@mary>
+
+       * Added overlay script that allows to easily mount mini_fo ontop
+       of a given base directory
+
+2005-05-10    <mk@mary>
+
+       * inode.c: xattr functions return -EOPNOSUPP instead of
+          -ENOSUPP, what confuses "ls -l"
+
+       * Changed license from LGPL to GPL.
+
+2005-05-08  root  <mk@mary>
+
+       * Makefile: clean it up and added make install and make
+          uninstall.
+       
+2005-05-06    <mk@mary>
+
+       * merged devel branch back to main. [v0-6-0-pre3]
+
+       * removed unused files print.c and fist_ioctl. [devel-0-0-18]
+
+       * ioctl: removed fist_ioctl stuff, that is not needed for
+          now.
+
+2005-05-03    <mk@mary>
+
+       * file.c: simplified mini_fo_open and mini_fo_setattr using
+          new state changing functions. [devel-0-0-17]
+
+       * inode.c: Fixed getattr state bug (see below) in 2.4 function
+          mini_fo_inode revalidate.
+
+       * inode.c: found an other bug in mini_fo_getattr. States are not
+         reliable in this function, as a file can be opened, unlinked and
+         the getattr function called. This results in a deleted dentry
+         with an inode. Fix is to ignore states and simply use the inode
+         available.
+
+2005-04-29    <mk@mary>
+
+       * file.c: Bugfix and cleanup in fasync and fsync. [devel-0-0-16]
+
+       * file.c: do not use mini_fo_lock so the generic version is
+          used (I guess).
+
+       * inode.c: getattr, never call getattr on lower files, as this
+          will cause the inum to change.
+
+       * inode.c: rename_reg_file renamed to rename_nondir, as it
+          doesn't matter as long it't not a dir. Removed all
+          rename_dev_file etc.           
+
+       * tagged as devel-0-0-15
+
+       * inode.c: added support for chosing support for extended
+          attrs at compile time by XATTR define in mini_fo.h .
+
+       * inode.c: fixed mini_fo_getattr to use mini_fo inode and not
+          lower again, what avoids inode number changes that confused
+          rm again. This is the proper solution.
+
+2005-04-24    <mk@mary>
+
+       * all files: updated Copyright notive to 2005. [devel-0-0-14]
+
+       * inode.c: fixed mini_fo_getattr to not change the inode
+          number, even if lower files change.
+
+       * super.c: fixed a bug that caused deleted base file to show
+          up suddenly after some time, or after creating a special
+          file. The problem was that after some time or after special
+          file creating sync_sb_inodes is called by the vfs, that
+          called our mini_fo_put_inode. There was (wrongly) called
+          __meta_put_lists, that nuked the lists, although the inode
+          was going to continue its life. Moving __meta_put_lists to
+          mini_fo_clear_inode, where an inode is really destroyed,
+          solved the problem.
+
+
+2005-04-23    <mk@mary>
+
+       * state.c, aux.c: more cleaning up and
+          simplifications. [devel-0-0-13] 
+
+       * inode.c: implemented mini_fo_getattr, that was required for
+          2.6 because inode_revalidate has been remove there, and the
+         old "du" bug returned.
+
+
+2005-04-20    <mk@mary>
+
+       * aux.c: get_neg_sto_dentry(): allow to be called for dentries
+          in state UNMODIFIED, NON_EXISTANT _and_ DELETED.
+
+2005-04-19    <mk@mary>
+
+       * Fixed a bug under 2.6 that caused files deleted via mini_fo
+          not to be deleted properly and therefore the fs filled up
+          untill no memory was left. [devel-0-0-12]
+
+       * Added basic hard link support. This means that creating
+          hardlinks will work, but existing ones will be treated as
+          individual files. [devel-0-0-11]
+
+2005-04-17    <mk@mary>
+
+       * Bugfixes
+
+2005-04-13  root  <mk@mary>
+
+       * Added file state.c for the state transition
+          functions. Doesn't work very well yet, though...
+
+2005-04-12    <mk@mary>
+
+       * Porting to 2.6 started, which is easier than expected, also
+          due to Olivier previous work.
+
+2005-04-08    <mk@mary>
+
+       * Fixed the bug that caused du to return invalid sizes of
+          directory trees. The problem was that
+          mini_fo_inode_revalidate didn't always copy the attributes
+          from the base inode properly.
+
+2005-04-01  Markus Klotzbuecher  <mk@chasey>
+
+       * Merged devel branch back to main trunk and updated the
+          RELEASE notes. This will be 0-6-0-pre1.
+
+2005-03-31  Markus Klotzbuecher  <mk@chasey>
+
+       * Fixed some bugs in rename_reg_file, that only showed up in
+          the kernel compile test. Kernel compiles cleanly ontop of
+          mini_fo, now also make mrproper etc. work. Seems pretty stable.
+
+2005-03-28  Markus Klotzbuecher  <mk@chasey>
+
+       * Many, many directory renaming bugfixes and a lot of other
+          cleanup. Dir renaming seems to work relatively stable.
+
+2005-03-22  Markus Klotzbuecher  <mk@chasey>
+
+       * Finished implementing lightweight directory renaming. Some
+          basic testing indicates it works fine.
+         Next is to implement testcases for the testsuite and confirm
+          everything is really working ok.
+
+2005-03-18  Markus Klotzbuecher  <mk@chasey>
+
+       * Finished implementing meta.c stuff required for directory
+          renaming.
+
+2005-03-17  Markus Klotzbuecher  <mk@chasey>
+
+       * Fixed all compile warnings + an extremly old bug that
+          somehow crept in while reworking the wol stuff to the META
+          system. Turning on -Werror again... :-)
+
+       * Fixed some bugs in the new rename_reg_file function.
+
+       * Rewrote mini_fo rename and split it into several
+          subfunctions, that handle the different types
+          seperately. Rewrote the regular file function aswell, as it
+          was implemented somewhat inefficient. 
+
+2005-03-16  Markus Klotzbuecher  <mk@chasey>
+
+       * Implemented new META subsystem, removed old WOL stuff in favor 
+         if it.
+
+       * After some basic testing everything seems ok...
+
+2005-03-11  Markus Klotzbuecher  <mk@chasey>
+
+       * Renaming a non regular file caused trouble because I always
+         tried to copy the contents. Now I only do this for regular
+         files. mini_fo_rename still isn't implemented properly, renaming
+         of device files, symlinks etc. results in a empty regular file
+         instead of the proper type.
+       
+       * Directory renaming suddenly works! What a surprise! I guess
+          this is because renaming is implemented as making a copy and
+          removing the original. Still this might not work
+          everywhere...
+
+2005-03-09  Markus Klotzbuecher  <mk@chasey>
+
+       * Bugfix, when a mini_fo directory that exists in storage
+         (state: MODIFIED, CREATED and DEL_REWRITTEN) is deleted, a
+         possibly existing WOL file contained in it needs to be
+         deleted too.
+
+       * Starting cleanup: defined state names in order to get rid of
+          the state numbers.
+
+2005-03-08  Markus Klotzbuecher  <mk@chasey>
+       
+       * Makefile fix, fist_ioctl was built against wrong sources if ARCH=um
+
+       * Fixed a bug in dentry.c, mini_fo_d_hash. In state 4 =
+          DEL_REWRITTEN the hash was calculated from the base dentry,
+          which was wrong and and caused assertions in
+          __mini_fo_hidden_dentry to fail.
+
+2005-02-21    <mk@mary>
+
+       * Implemented directory deleting (inode.c)
+
+       * main.c: made mini_fo_parse_options a little more robust.
+
+2004-12-22    <mk@mary>
+
+       * Makefile cleanup and uml stuff, removed unneccessary files
+
+       * Created a new and hopefully more informative README
+
+       * CHANGELOG: created a new CHANGELOG and added old entries reversely
+
+
+2004-10-24 Gleb Natapov <gleb@nbase.co.il>
+
+       * Fix: owner and group where not correctly copied from base to
+          storage. 
+
+
+2004-10-05 Gleb Natapov <gleb@nbase.co.il>
+
+       * Implementation of fsync, fasync and lock mini_fo functions.
+       
+
+2004-09-29 Bob Lee <bob@pantasys.com>
+
+       * Fix of a serious pointer bug
+       
+
+2004-09-28 Gleb Natapov <gleb@nbase.co.il>
+
+       * Implementation of mini_fo_mknod and mini_fo_rename, support
+          for device files.
+       
diff -urN linux-2.6.21.1.old/fs/mini_fo/dentry.c linux-2.6.21.1.dev/fs/mini_fo/dentry.c
--- linux-2.6.21.1.old/fs/mini_fo/dentry.c      1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.21.1.dev/fs/mini_fo/dentry.c      2007-05-26 21:01:26.161330176 +0200
@@ -0,0 +1,244 @@
+/*
+ * Copyright (c) 1997-2003 Erez Zadok
+ * Copyright (c) 2001-2003 Stony Brook University
+ *
+ * For specific licensing information, see the COPYING file distributed with
+ * this package, or get one from ftp://ftp.filesystems.org/pub/fist/COPYING.
+ *
+ * This Copyright notice must be kept intact and distributed with all
+ * fistgen sources INCLUDING sources generated by fistgen.
+ */
+/*
+ * Copyright (C) 2004, 2005 Markus Klotzbuecher <mk@creamnet.de>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+/*
+ *  $Id$
+ */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include "fist.h"
+#include "mini_fo.h"
+
+/*
+ * THIS IS A BOOLEAN FUNCTION: returns 1 if valid, 0 otherwise.
+ */
+STATIC int
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
+mini_fo_d_revalidate(dentry_t *dentry, struct nameidata *nd)
+#else
+mini_fo_d_revalidate(dentry_t *dentry, int flags)
+#endif
+{
+       int err1 = 1; /* valid = 1, invalid = 0 */
+       int err2 = 1;
+       dentry_t *hidden_dentry;
+       dentry_t *hidden_sto_dentry;
+
+
+       check_mini_fo_dentry(dentry);
+
+       hidden_dentry  = dtohd(dentry);
+       hidden_sto_dentry = dtohd2(dentry);
+
+       if(hidden_dentry &&
+          hidden_dentry->d_op &&
+          hidden_dentry->d_op->d_revalidate) {
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
+               err1 = hidden_dentry->d_op->d_revalidate(hidden_dentry, nd);
+#else
+               err1 = hidden_dentry->d_op->d_revalidate(hidden_dentry, flags);
+#endif
+       }
+       if(hidden_sto_dentry &&
+          hidden_sto_dentry->d_op &&
+          hidden_sto_dentry->d_op->d_revalidate) {
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
+               err2 = hidden_sto_dentry->d_op->d_revalidate(hidden_sto_dentry, 
+                                                            nd);
+#else
+               err2 = hidden_sto_dentry->d_op->d_revalidate(hidden_sto_dentry, 
+                                                            flags);
+#endif
+       }
+
+       /* mk: if one of the lower level dentries are valid,
+        * the mini_fo dentry is too.
+        */
+       return (err1 || err2);
+}
+
+
+STATIC int
+mini_fo_d_hash(dentry_t *dentry, qstr_t *name)
+{
+       int err = 0;
+       dentry_t *hidden_dentry;
+       dentry_t *hidden_sto_dentry;
+
+       /* hidden_dentry = mini_fo_hidden_dentry(dentry);
+        * hidden_sto_dentry = mini_fo_hidden_sto_dentry(dentry); */
+
+       /* state 1, 3, 4, 5: build the hash for the storage dentry */
+       if((dtopd(dentry)->state == MODIFIED) ||
+          (dtopd(dentry)->state == CREATED) ||
+          (dtopd(dentry)->state == DEL_REWRITTEN) ||
+          (dtopd(dentry)->state == DELETED)) {
+               hidden_sto_dentry = dtohd2(dentry);
+               if(hidden_sto_dentry &&
+                  hidden_sto_dentry->d_op &&
+                  hidden_sto_dentry->d_op->d_hash) {
+                       err = hidden_sto_dentry->d_op->d_hash(hidden_sto_dentry, name);
+               }
+               goto out;
+       }
+       /* state 2: build the hash for the base dentry */
+       if(dtopd(dentry)->state == UNMODIFIED) {
+               hidden_dentry = dtohd(dentry);
+               if(hidden_dentry &&
+                  hidden_dentry->d_op &&
+                  hidden_dentry->d_op->d_hash) {
+                       err = hidden_dentry->d_op->d_hash(hidden_dentry, name);
+               }
+               goto out;
+       }
+       /* state 6: build hash for the dentry that exists */
+       if(dtopd(dentry)->state == NON_EXISTANT) {
+               hidden_sto_dentry = dtohd2(dentry);
+               if(hidden_sto_dentry &&
+                  hidden_sto_dentry->d_op &&
+                  hidden_sto_dentry->d_op->d_hash) {
+                       err = hidden_sto_dentry->d_op->d_hash(hidden_sto_dentry, name);
+                       goto out;
+               }
+               hidden_dentry = dtohd(dentry);
+               if(hidden_dentry &&
+                  hidden_dentry->d_op &&
+                  hidden_dentry->d_op->d_hash) {
+                       err = hidden_dentry->d_op->d_hash(hidden_dentry, name);
+                       goto out;
+               }
+       }
+
+       printk(KERN_CRIT "mini_fo: d_hash: invalid state detected.\n");
+
+ out:
+       return err;
+}
+
+
+STATIC int
+mini_fo_d_compare(dentry_t *dentry, qstr_t *a, qstr_t *b)
+{
+       int err;
+       dentry_t *hidden_dentry=NULL;
+
+       /* hidden_dentry = mini_fo_hidden_dentry(dentry); */
+       if(dtohd2(dentry))
+               hidden_dentry = dtohd2(dentry);
+       else if(dtohd(dentry))
+               hidden_dentry = dtohd(dentry);
+
+       if (hidden_dentry && hidden_dentry->d_op && hidden_dentry->d_op->d_compare) {
+               err = hidden_dentry->d_op->d_compare(hidden_dentry, a, b);
+       } else {
+               err = ((a->len != b->len) || memcmp(a->name, b->name, b->len));
+       }
+
+       return err;
+}
+
+
+int
+mini_fo_d_delete(dentry_t *dentry)
+{
+       dentry_t *hidden_dentry;
+       dentry_t *hidden_sto_dentry;
+       int err = 0;
+
+       /* this could be a negative dentry, so check first */
+       if (!dtopd(dentry)) {
+               printk(KERN_CRIT "mini_fo_d_delete: negative dentry passed.\n");
+               goto out;
+       }
+       hidden_dentry = dtohd(dentry);
+       hidden_sto_dentry = dtohd2(dentry);
+
+       if(hidden_dentry) {
+               if(hidden_dentry->d_op &&
+                  hidden_dentry->d_op->d_delete) {
+                       err = hidden_dentry->d_op->d_delete(hidden_dentry);
+               }
+       }
+       if(hidden_sto_dentry) {
+               if(hidden_sto_dentry->d_op &&
+                  hidden_sto_dentry->d_op->d_delete) {
+                       err = hidden_sto_dentry->d_op->d_delete(hidden_sto_dentry);
+               }
+       }
+
+ out:
+       return err;
+}
+
+
+void
+mini_fo_d_release(dentry_t *dentry)
+{
+       dentry_t *hidden_dentry;
+       dentry_t *hidden_sto_dentry;
+
+
+       /* this could be a negative dentry, so check first */
+       if (!dtopd(dentry)) {
+               printk(KERN_CRIT "mini_fo_d_release: no private data.\n");
+               goto out;
+       }
+       hidden_dentry = dtohd(dentry);
+       hidden_sto_dentry = dtohd2(dentry);
+
+       if(hidden_dentry) {
+               /* decrement hidden dentry's counter and free its inode */
+               dput(hidden_dentry);
+       }
+       if(hidden_sto_dentry) {
+                /* decrement hidden dentry's counter and free its inode */
+               dput(hidden_sto_dentry);
+       }
+
+       /* free private data (mini_fo_dentry_info) here */
+       kfree(dtopd(dentry));
+       __dtopd(dentry) = NULL; /* just to be safe */
+ out:
+       return;
+}
+
+
+/*
+ * we don't really need mini_fo_d_iput, because dentry_iput will call iput() if
+ * mini_fo_d_iput is not defined. We left this implemented for ease of
+ * tracing/debugging.
+ */
+void
+mini_fo_d_iput(dentry_t *dentry, inode_t *inode)
+{
+       iput(inode);
+}
+
+
+struct dentry_operations mini_fo_dops = {
+       d_revalidate:   mini_fo_d_revalidate,
+       d_hash:         mini_fo_d_hash,
+       d_compare:              mini_fo_d_compare,
+       d_release:              mini_fo_d_release,
+       d_delete:               mini_fo_d_delete,
+       d_iput:         mini_fo_d_iput,
+};
diff -urN linux-2.6.21.1.old/fs/mini_fo/file.c linux-2.6.21.1.dev/fs/mini_fo/file.c
--- linux-2.6.21.1.old/fs/mini_fo/file.c        1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.21.1.dev/fs/mini_fo/file.c        2007-05-26 21:01:26.162330024 +0200
@@ -0,0 +1,713 @@
+/*
+ * Copyright (c) 1997-2003 Erez Zadok
+ * Copyright (c) 2001-2003 Stony Brook University
+ *
+ * For specific licensing information, see the COPYING file distributed with
+ * this package, or get one from ftp://ftp.filesystems.org/pub/fist/COPYING.
+ *
+ * This Copyright notice must be kept intact and distributed with all
+ * fistgen sources INCLUDING sources generated by fistgen.
+ */
+/*
+ * Copyright (C) 2004, 2005 Markus Klotzbuecher <mk@creamnet.de>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+/*
+ *  $Id$
+ */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include "fist.h"
+#include "mini_fo.h"
+#define ROUND_UP(x) (((x)+sizeof(long)-1) & ~(sizeof(long)-1))
+
+/*******************
+ * File Operations *
+ *******************/
+
+STATIC loff_t
+mini_fo_llseek(file_t *file, loff_t offset, int origin)
+{
+       loff_t err;
+       file_t *hidden_file = NULL;
+
+       if(S_ISDIR(file->f_dentry->d_inode->i_mode)) {
+               /* Check if trying to llseek from a directory */
+               err = -EISDIR;
+               goto out;
+       }
+       if (ftopd(file) != NULL) {
+               if(ftohf2(file)) {
+                       hidden_file = ftohf2(file);
+               } else {
+                       hidden_file = ftohf(file);
+               }
+       }
+
+       /* always set hidden position to this one */
+       hidden_file->f_pos = file->f_pos;
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
+       memcpy(&(hidden_file->f_ra), 
+              &(file->f_ra), 
+              sizeof(struct file_ra_state));
+#else
+       if (file->f_reada) { /* update readahead information if needed */
+               hidden_file->f_reada = file->f_reada;
+               hidden_file->f_ramax = file->f_ramax;
+               hidden_file->f_raend = file->f_raend;
+               hidden_file->f_ralen = file->f_ralen;
+               hidden_file->f_rawin = file->f_rawin;
+       }
+#endif
+       if (hidden_file->f_op && hidden_file->f_op->llseek)
+               err = hidden_file->f_op->llseek(hidden_file, offset, origin);
+       else
+               err = generic_file_llseek(hidden_file, offset, origin);
+
+       if (err < 0)
+               goto out;
+
+       if (err != file->f_pos) {
+               file->f_pos = err;
+               // ION maybe this?
+               //      file->f_pos = hidden_file->f_pos;
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
+               file->f_reada = 0;
+#endif
+               file->f_version++;
+       }
+
+ out:
+       return err;
+}
+
+
+/* mk: fanout capable */
+STATIC ssize_t
+mini_fo_read(file_t *file, char *buf, size_t count, loff_t *ppos)
+{
+       int err = -EINVAL;
+       file_t *hidden_file = NULL;
+       loff_t pos = *ppos;
+
+       if(S_ISDIR(file->f_dentry->d_inode->i_mode)) {
+               /* Check if trying to read from a directory */
+               /* printk(KERN_CRIT "mini_fo_read: ERROR: trying to read data from a directory.\n"); */
+               err = -EISDIR;
+               goto out;
+       }
+
+       if (ftopd(file) != NULL) {
+               if(ftohf2(file)) {
+                       hidden_file = ftohf2(file);
+               } else {
+                       hidden_file = ftohf(file);
+               }
+       }
+
+       if (!hidden_file->f_op || !hidden_file->f_op->read)
+               goto out;
+
+       err = hidden_file->f_op->read(hidden_file, buf, count, &pos);
+       *ppos = pos;
+
+       if (err >= 0) {
+               /* atime should also be updated for reads of size zero or more */
+               fist_copy_attr_atime(file->f_dentry->d_inode,
+                                    hidden_file->f_dentry->d_inode);
+       }
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
+       /*
+        * MAJOR HACK
+        * because pread() does not have any way to tell us that it is
+        * our caller, then we don't know for sure if we have to update
+        * the file positions.  This hack relies on read() having passed us
+        * the "real" pointer of its struct file's f_pos field.
+        */
+       if (ppos == &file->f_pos)
+               hidden_file->f_pos = *ppos = pos;
+       if (hidden_file->f_reada) { /* update readahead information if needed */
+               file->f_reada = hidden_file->f_reada;
+               file->f_ramax = hidden_file->f_ramax;
+               file->f_raend = hidden_file->f_raend;
+               file->f_ralen = hidden_file->f_ralen;
+               file->f_rawin = hidden_file->f_rawin;
+       }
+#else
+       memcpy(&(file->f_ra),&(hidden_file->f_ra),sizeof(struct file_ra_state));
+#endif
+
+ out:
+       return err;
+}
+
+
+/* this mini_fo_write() does not modify data pages! */
+STATIC ssize_t
+mini_fo_write(file_t *file, const char *buf, size_t count, loff_t *ppos)
+{
+       int err = -EINVAL;
+       file_t *hidden_file = NULL;
+       inode_t *inode;
+       inode_t *hidden_inode;
+       loff_t pos = *ppos;
+
+       /* mk: fan out: */
+       if (ftopd(file) != NULL) {
+               if(ftohf2(file)) {
+                       hidden_file = ftohf2(file);
+               } else {
+                       /* This is bad! We have no storage file to write to. This
+                        * should never happen because if a file is opened for
+                        * writing, a copy should have been made earlier.
+                        */
+                       printk(KERN_CRIT "mini_fo: write : ERROR, no storage file to write.\n");
+                       err = -EINVAL;
+                       goto out;
+               }
+       }
+
+       inode = file->f_dentry->d_inode;
+       hidden_inode = itohi2(inode);
+       if(!hidden_inode) {
+               printk(KERN_CRIT "mini_fo: write: no sto inode found, not good.\n");
+               goto out;
+       }
+
+       if (!hidden_file->f_op || !hidden_file->f_op->write)
+               goto out;
+
+       /* adjust for append -- seek to the end of the file */
+       if (file->f_flags & O_APPEND)
+               pos = inode->i_size;
+
+       err = hidden_file->f_op->write(hidden_file, buf, count, &pos);
+
+       /*
+        * copy ctime and mtime from lower layer attributes
+        * atime is unchanged for both layers
+        */
+       if (err >= 0)
+               fist_copy_attr_times(inode, hidden_inode);
+       
+       *ppos = pos;
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
+       /*
+        * XXX: MAJOR HACK
+        *
+        * because pwrite() does not have any way to tell us that it is
+        * our caller, then we don't know for sure if we have to update
+        * the file positions.  This hack relies on write() having passed us
+        * the "real" pointer of its struct file's f_pos field.
+        */
+       if (ppos == &file->f_pos)
+               hidden_file->f_pos = *ppos = pos;
+#endif
+       /* update this inode's size */
+       if (pos > inode->i_size)
+               inode->i_size = pos;
+
+ out:
+       return err;
+}
+
+/* Global variable to hold a file_t pointer.
+ * This serves to allow mini_fo_filldir function to know which file is
+ * beeing read, which is required for two reasons:
+ *
+ *   - be able to call wol functions in order to avoid listing deleted
+ *     base files.
+ *   - if we're reading a directory which is in state 1, we need to
+ *     maintain a list (in mini_fo_filldir) of which files allready 
+ *     have been copied to userspace,to detect files existing in base
+ *     and storage and not list them twice.
+ */
+filldir_t mini_fo_filldir_orig;
+file_t *mini_fo_filldir_file;
+
+/* mainly copied from fs/readdir.c */
+STATIC int
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,18)
+mini_fo_filldir(void * __buf, const char * name, int namlen, loff_t offset,
+                 u64 ino, unsigned int d_type)
+#else
+mini_fo_filldir(void * __buf, const char * name, int namlen, loff_t offset,
+                 ino_t ino, unsigned int d_type)
+#endif
+{
+       struct getdents_callback * buf = (struct getdents_callback *) __buf;
+       file_t* file = mini_fo_filldir_file;
+
+       /* In theses states we filter meta files in storage (WOL) */
+       if(file && (dtopd(file->f_dentry)->state == MODIFIED ||
+                   dtopd(file->f_dentry)->state == CREATED ||
+                   dtopd(file->f_dentry)->state == DEL_REWRITTEN)) {
+
+               int tmp = strlen(META_FILENAME);
+               if(tmp  == namlen) {
+                       if(!strncmp(name, META_FILENAME, namlen))
+                               return 0;
+               }
+       }
+
+       /* check if we are merging the contents of storage and base */
+       if(file && dtopd(file->f_dentry)->state == MODIFIED) {
+               /* check if we are still reading storage contents, if
+                * yes, we just save the name of the file for duplicate
+                * checking later. */
+
+               if(!ftopd(file)->rd.sto_done) {
+                       /* put file into ndl list */
+                       if(ndl_add_entry(&ftopd(file)->rd, name, namlen))
+                               printk(KERN_CRIT "mini_fo_filldir: Error adding to ndl.\n");
+               } else {
+                       /* check if file has been deleted */
+                       if(meta_check_d_entry(file->f_dentry, name, namlen))
+                               return 0;
+                       
+                       /* do duplicate checking */
+                       if(ndl_check_entry(&ftopd(file)->rd, name, namlen))
+                               return 0;
+               }
+       }
+
+       return mini_fo_filldir_orig(buf, name, namlen, offset, ino, d_type);
+}
+
+
+STATIC int
+mini_fo_readdir(file_t *file, void *dirent, filldir_t filldir)
+{
+       int err = 0;/* mk: ??? -ENOTDIR; */
+       file_t *hidden_file = NULL;
+       file_t *hidden_sto_file = NULL;
+       inode_t *inode;
+       struct getdents_callback *buf;
+       int oldcount;
+
+#if defined(FIST_FILTER_NAME) || defined(FIST_FILTER_SCA)
+       struct mini_fo_getdents_callback buf;
+#endif /* FIST_FILTER_NAME || FIST_FILTER_SCA */
+
+       buf = (struct getdents_callback *) dirent;
+       oldcount = buf->count;
+       inode = file->f_dentry->d_inode;
+       mini_fo_filldir_file = file;
+       mini_fo_filldir_orig = filldir;
+
+       ftopd(file)->rd.sto_done = 0;
+       do {
+               if (ftopd(file) != NULL) {
+                       if(ftohf2(file)) { 
+                               hidden_sto_file = ftohf2(file);
+                               err = vfs_readdir(hidden_sto_file, mini_fo_filldir, dirent);
+                               file->f_pos = hidden_sto_file->f_pos;
+                               if (err > 0)
+                                       fist_copy_attr_atime(inode, hidden_sto_file->f_dentry->d_inode);
+                               /* not finshed yet, we'll be called again */
+                               if (buf->count != oldcount)
+                                       break;
+                       }
+
+                       ftopd(file)->rd.sto_done = 1;
+
+                       if(ftohf(file)) { 
+                               hidden_file = ftohf(file);
+                               err = vfs_readdir(hidden_file, mini_fo_filldir, dirent);
+                               file->f_pos = hidden_file->f_pos;
+                               if (err > 0)
+                                       fist_copy_attr_atime(inode, hidden_file->f_dentry->d_inode);
+                       }
+
+               }
+       } while (0);
+
+       /* mk:
+        * we need to check if all the directory data has been copied to userspace,
+        * or if we will be called again by userspace to complete the operation.
+        */
+       if(buf->count == oldcount) {
+               ndl_put_list(&ftopd(file)->rd);
+       }
+
+       /* unset this, safe */
+       mini_fo_filldir_file = NULL;
+       return err;
+}
+
+
+STATIC unsigned int
+mini_fo_poll(file_t *file, poll_table *wait)
+{
+       unsigned int mask = DEFAULT_POLLMASK;
+       file_t *hidden_file = NULL;
+
+       if (ftopd(file) != NULL) {
+               if(ftohf2(file)) {
+                       hidden_file = ftohf2(file);
+               } else {
+                       hidden_file = ftohf(file);
+               }
+       }
+
+       if (!hidden_file->f_op || !hidden_file->f_op->poll)
+               goto out;
+
+       mask = hidden_file->f_op->poll(hidden_file, wait);
+
+ out:
+       return mask;
+}
+
+/* FIST-LITE special version of mmap */
+STATIC int
+mini_fo_mmap(file_t *file, vm_area_t *vma)
+{
+       int err = 0;
+       file_t *hidden_file = NULL;
+
+       /* fanout capability */
+       if (ftopd(file) != NULL) {
+               if(ftohf2(file)) {
+                       hidden_file = ftohf2(file);
+               } else {
+                       hidden_file = ftohf(file);
+               }
+       }
+
+       ASSERT(hidden_file != NULL);
+       ASSERT(hidden_file->f_op != NULL);
+       ASSERT(hidden_file->f_op->mmap != NULL);
+
+       vma->vm_file = hidden_file;
+       err = hidden_file->f_op->mmap(hidden_file, vma);
+       get_file(hidden_file); /* make sure it doesn't get freed on us */
+       fput(file);            /* no need to keep extra ref on ours */
+
+       return err;
+}
+
+
+
+STATIC int
+mini_fo_open(inode_t *inode, file_t *file)
+{
+       int err = 0;
+       int hidden_flags; 
+       file_t *hidden_file = NULL;
+       dentry_t *hidden_dentry = NULL;
+
+       /* fanout stuff */
+       file_t *hidden_sto_file = NULL;
+       dentry_t *hidden_sto_dentry = NULL;
+
+       __ftopd(file) = 
+               kmalloc(sizeof(struct mini_fo_file_info), GFP_KERNEL);
+       if (!ftopd(file)) {
+               err = -ENOMEM;
+               goto out;
+       }
+
+       /* init the readdir_helper structure */
+       INIT_LIST_HEAD(&ftopd(file)->rd.ndl_list);
+       ftopd(file)->rd.ndl_size = 0;
+
+       /* In certain paths this could stay uninitalized and cause trouble */
+       ftohf(file) = NULL;
+       ftohf2(file) = NULL;
+       hidden_flags = file->f_flags;
+
+       /* create storage files? */
+       if(dtost(file->f_dentry) == UNMODIFIED) {
+               if(!IS_WRITE_FLAG(file->f_flags)) {
+                       hidden_dentry = dtohd(file->f_dentry);
+                       dget(hidden_dentry);
+                       /* dentry_open will decrement mnt refcnt if err.
+                        * otherwise fput() will do an mntput() for us upon file close. */
+                       mntget(stopd(inode->i_sb)->hidden_mnt);
+                       hidden_file = dentry_open(hidden_dentry,
+                                                 stopd(inode->i_sb)->hidden_mnt,
+                                                 hidden_flags);
+                       if (IS_ERR(hidden_file)) {
+                               err = PTR_ERR(hidden_file);
+                               dput(hidden_dentry);
+                               goto out;
+                       }
+                       ftohf(file) = hidden_file;      /* link two files */
+                       goto out;
+               }
+               else {
+                       if(S_ISDIR(file->f_dentry->d_inode->i_mode)) {
+                               err = dir_unmod_to_mod(file->f_dentry);
+                       } else
+                               err = nondir_unmod_to_mod(file->f_dentry, 1);
+
+                       if (err) {
+                               printk("mini_fo_open: ERROR creating storage file.\n");
+                               goto out;
+                       }
+               }
+       }
+       hidden_sto_dentry = dtohd2(file->f_dentry);
+       dget(hidden_sto_dentry);
+
+       if(dtopd(file->f_dentry)->state == MODIFIED) {
+               /* Directorys are special, interpose on both lower level files */
+               if(S_ISDIR(itohi(inode)->i_mode)) {
+                       /* check for invalid file types of lower level files */
+                       if(!(S_ISDIR(itohi(inode)->i_mode) && S_ISDIR(itohi2(inode)->i_mode))) {
+                               printk(KERN_CRIT "mini_fo_open: meta data corruption detected.\n");
+                               dput(hidden_sto_dentry);
+                               err = -EINVAL;
+                               goto out;
+                       }
+
+                       /* lower level directorys are ok, open the base file */
+                       hidden_dentry = dtohd(file->f_dentry);
+                       dget(hidden_dentry);
+
+                       mntget(stopd(inode->i_sb)->hidden_mnt);
+                       hidden_file = dentry_open(hidden_dentry,
+                                                 stopd(inode->i_sb)->hidden_mnt,
+                                                 hidden_flags);
+                       if (IS_ERR(hidden_file)) {
+                               err = PTR_ERR(hidden_file);
+                               dput(hidden_dentry);
+                               dput(hidden_sto_dentry);
+                               goto out;
+                       }
+                       ftohf(file) = hidden_file; /* link the two files */
+               }
+       }
+
+       if(!exists_in_storage(file->f_dentry)) {
+               printk(KERN_CRIT "mini_fo_open: invalid file state detected.\n");
+               err = -EINVAL;
+               dput(hidden_sto_dentry);
+
+               /* If the base file has been opened, we need to close it here */
+               if(ftohf(file)) {
+                       if (hidden_file->f_op && hidden_file->f_op->flush)
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,18)
+                               hidden_file->f_op->flush(hidden_file, NULL);
+#else
+                               hidden_file->f_op->flush(hidden_file);
+#endif
+                       dput(hidden_dentry);
+               }
+               goto out;
+       }
+
+       /* ok, now we can safely open the storage file */
+       mntget(stopd(inode->i_sb)->hidden_mnt2);
+       hidden_sto_file = dentry_open(hidden_sto_dentry,
+                                     stopd(inode->i_sb)->hidden_mnt2,
+                                     hidden_flags);
+
+       /* dentry_open dputs the dentry if it fails */
+       if (IS_ERR(hidden_sto_file)) {
+               err = PTR_ERR(hidden_sto_file);
+               /* close base file if open */
+               if(ftohf(file)) {
+                       if (hidden_file->f_op && hidden_file->f_op->flush)
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,18)
+                               hidden_file->f_op->flush(hidden_file, NULL);
+#else
+                               hidden_file->f_op->flush(hidden_file);
+#endif
+                       dput(hidden_dentry);
+               }
+               goto out;
+       }
+       ftohf2(file) = hidden_sto_file; /* link storage file */
+       
+ out:
+       if (err < 0 && ftopd(file)) {
+               kfree(ftopd(file));
+       }
+       return err;
+}
+
+STATIC int
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,18)
+mini_fo_flush(file_t *file, fl_owner_t id)
+#else
+mini_fo_flush(file_t *file)
+#endif
+{
+       int err1 = 0;           /* assume ok (see open.c:close_fp) */
+       int err2 = 0;
+       file_t *hidden_file = NULL;
+       
+       check_mini_fo_file(file);
+
+       /* mk: we don't do any state checking here, as its not worth the time.
+        * Just flush the lower level files if they exist.
+        */
+       if(ftopd(file) != NULL) {
+               if(ftohf(file) != NULL) {
+                       hidden_file = ftohf(file);
+                       if (hidden_file->f_op && hidden_file->f_op->flush)
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,18)
+                               err1 = hidden_file->f_op->flush(hidden_file, id);
+#else
+                               err1 = hidden_file->f_op->flush(hidden_file);
+#endif
+               }
+               if(ftohf2(file) != NULL) {
+                       hidden_file = ftohf2(file);
+                       if (hidden_file->f_op && hidden_file->f_op->flush)
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,18)
+                               err2 = hidden_file->f_op->flush(hidden_file, id);
+#else
+                               err2 = hidden_file->f_op->flush(hidden_file);
+#endif
+               }
+       }
+       return (err1 | err2);
+}
+
+
+STATIC int
+mini_fo_release(inode_t *inode, file_t *file)
+{
+       int err = 0;
+       file_t *hidden_file = NULL;
+
+       if (ftopd(file) != NULL) {
+               if(ftohf(file)) {
+                       hidden_file = ftohf(file);
+                       fput(hidden_file);
+               }
+               if(ftohf2(file)) {
+                       hidden_file = ftohf2(file);
+                       fput(hidden_file);
+               }
+               kfree(ftopd(file));
+       }
+       return err;
+}
+
+STATIC int
+mini_fo_fsync(file_t *file, dentry_t *dentry, int datasync)
+{
+       int err1 = 0;
+       int err2 = 0;
+       file_t *hidden_file = NULL;
+       dentry_t *hidden_dentry;
+
+       check_mini_fo_file(file);
+
+       if ((hidden_file = ftohf(file)) != NULL) {
+               hidden_dentry = dtohd(dentry);
+               if (hidden_file->f_op && hidden_file->f_op->fsync) {
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
+                       mutex_lock(&hidden_dentry->d_inode->i_mutex);
+#else
+                       down(&hidden_dentry->d_inode->i_sem);
+#endif
+                       err1 = hidden_file->f_op->fsync(hidden_file, hidden_dentry, datasync);
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
+                       mutex_unlock(&hidden_dentry->d_inode->i_mutex);
+#else
+                       up(&hidden_dentry->d_inode->i_sem);
+#endif
+               }
+       }
+
+       if ((hidden_file = ftohf2(file)) != NULL) {
+               hidden_dentry = dtohd2(dentry);
+               if (hidden_file->f_op && hidden_file->f_op->fsync) {
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
+                       mutex_lock(&hidden_dentry->d_inode->i_mutex);
+#else
+                       down(&hidden_dentry->d_inode->i_sem);
+#endif
+                       err2 = hidden_file->f_op->fsync(hidden_file, hidden_dentry, datasync);
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
+                       mutex_unlock(&hidden_dentry->d_inode->i_mutex);
+#else
+                       up(&hidden_dentry->d_inode->i_sem);
+#endif
+               }
+       }
+       else
+               goto err;
+
+err:
+       return (err1 || err2);
+}
+
+
+STATIC int
+mini_fo_fasync(int fd, file_t *file, int flag)
+{
+       int err1 = 0;
+       int err2 = 0;
+
+       file_t *hidden_file = NULL;
+
+       check_mini_fo_file(file);
+
+       if((hidden_file = ftohf(file)) != NULL) {
+               err1 = hidden_file->f_op->fasync(fd, hidden_file, flag);
+       }
+       if((hidden_file = ftohf2(file)) != NULL) {
+               err2 = hidden_file->f_op->fasync(fd, hidden_file, flag);
+       }
+       
+       return (err1 || err2);
+}
+
+
+
+struct file_operations mini_fo_dir_fops =
+       {
+               read:   generic_read_dir,
+               write:  mini_fo_write,
+               readdir: mini_fo_readdir,
+               poll:   mini_fo_poll,
+               /* ioctl:       mini_fo_ioctl, */
+               mmap:   mini_fo_mmap,
+               open:   mini_fo_open,
+               flush:  mini_fo_flush,
+               release: mini_fo_release,
+               fsync:  mini_fo_fsync,
+               fasync: mini_fo_fasync,
+               /* not needed lock:     mini_fo_lock, */
+               /* not needed: readv */
+               /* not needed: writev */
+               /* not implemented: sendpage */
+               /* not implemented: get_unmapped_area */
+       };
+
+struct file_operations mini_fo_main_fops =
+       {
+               llseek: mini_fo_llseek,
+               read:   mini_fo_read,
+               write:  mini_fo_write,
+               readdir: mini_fo_readdir,
+               poll:   mini_fo_poll,
+               /* ioctl:       mini_fo_ioctl, */
+               mmap:   mini_fo_mmap,
+               open:   mini_fo_open,
+               flush:  mini_fo_flush,
+               release: mini_fo_release,
+               fsync:  mini_fo_fsync,
+               fasync: mini_fo_fasync,
+               /* not needed: lock:    mini_fo_lock, */
+               /* not needed: readv */
+               /* not needed: writev */
+               /* not implemented: sendpage */
+               /* not implemented: get_unmapped_area */
+       };
diff -urN linux-2.6.21.1.old/fs/mini_fo/fist.h linux-2.6.21.1.dev/fs/mini_fo/fist.h
--- linux-2.6.21.1.old/fs/mini_fo/fist.h        1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.21.1.dev/fs/mini_fo/fist.h        2007-05-26 21:01:26.162330024 +0200
@@ -0,0 +1,252 @@
+/*
+ * Copyright (c) 1997-2003 Erez Zadok
+ * Copyright (c) 2001-2003 Stony Brook University
+ *
+ * For specific licensing information, see the COPYING file distributed with
+ * this package, or get one from ftp://ftp.filesystems.org/pub/fist/COPYING.
+ *
+ * This Copyright notice must be kept intact and distributed with all
+ * fistgen sources INCLUDING sources generated by fistgen.
+ */
+/*
+ * Copyright (C) 2004, 2005 Markus Klotzbuecher <mk@creamnet.de>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+
+/*
+ *  $Id$
+ */
+
+#ifndef __FIST_H_
+#define __FIST_H_
+
+/*
+ * KERNEL ONLY CODE:
+ */
+#ifdef __KERNEL__
+#include <linux/version.h>
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,19)
+#include <linux/autoconf.h>
+#else
+#include <linux/config.h>
+#endif
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
+#ifdef CONFIG_MODVERSIONS
+# define MODVERSIONS
+# include <linux/modversions.h>
+#endif /* CONFIG_MODVERSIONS */
+#endif /* KERNEL_VERSION < 2.6.0 */
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/string.h>
+#include <linux/stat.h>
+#include <linux/errno.h>
+#include <linux/wait.h>
+#include <linux/limits.h>
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
+#include <linux/locks.h>
+#else
+#include <linux/buffer_head.h>
+#include <linux/pagemap.h>
+#include <linux/namei.h>
+#include <linux/module.h>
+#include <linux/mount.h>
+#include <linux/page-flags.h>
+#include <linux/writeback.h>
+#include <linux/statfs.h>
+#endif
+#include <linux/smp.h>
+#include <linux/smp_lock.h>
+#include <linux/file.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/poll.h>
+#include <linux/list.h>
+#include <linux/init.h>
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,4,20)
+#include <linux/xattr.h>
+#endif
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
+#include <linux/security.h>
+#endif
+
+#include <linux/swap.h>
+
+#include <asm/system.h>
+/* #include <asm/segment.h> */
+#include <asm/mman.h>
+#include <linux/seq_file.h>
+
+/*
+ * MACROS:
+ */
+
+/* those mapped to ATTR_* were copied from linux/fs.h */
+#define FA_MODE                ATTR_MODE
+#define FA_UID         ATTR_UID
+#define FA_GID         ATTR_GID
+#define FA_SIZE                ATTR_SIZE
+#define FA_ATIME       ATTR_ATIME
+#define FA_MTIME       ATTR_MTIME
+#define FA_CTIME       ATTR_CTIME
+#define FA_ATIME_SET   ATTR_ATIME_SET
+#define FA_MTIME_SET   ATTR_MTIME_SET
+#define FA_FORCE       ATTR_FORCE
+#define FA_ATTR_FLAGS  ATTR_ATTR_FLAG
+
+/* must be greater than all other ATTR_* flags! */
+#define FA_NLINK       2048
+#define FA_BLKSIZE     4096
+#define FA_BLOCKS      8192
+#define FA_TIMES       (FA_ATIME|FA_MTIME|FA_CTIME)
+#define FA_ALL         0
+
+/* macros to manage changes between kernels */
+#define INODE_DATA(i)  (&(i)->i_data)
+
+#define MIN(x,y) ((x < y) ? (x) : (y))
+#define MAX(x,y) ((x > y) ? (x) : (y))
+#define MAXPATHLEN PATH_MAX
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,4,5)
+# define lookup_one_len(a,b,c) lookup_one(a,b)
+#endif /* LINUX_VERSION_CODE < KERNEL_VERSION(2,4,5) */
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,4,8)
+# define generic_file_llseek default_llseek
+#endif /* LINUX_VERSION_CODE < KERNEL_VERSION(2,4,8) */
+
+#ifndef SEEK_SET
+# define SEEK_SET 0
+#endif /* not SEEK_SET */
+
+#ifndef SEEK_CUR
+# define SEEK_CUR 1
+#endif /* not SEEK_CUR */
+
+#ifndef SEEK_END
+# define SEEK_END 2
+#endif /* not SEEK_END */
+
+#ifndef DEFAULT_POLLMASK
+# define DEFAULT_POLLMASK (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM)
+#endif /* not DEFAULT_POLLMASK */
+
+/* XXX: fix this so fistgen generates kfree() code directly */
+#define kfree_s(a,b) kfree(a)
+
+/*
+ * TYPEDEFS:
+ */
+typedef struct dentry dentry_t;
+typedef struct file file_t;
+typedef struct inode inode_t;
+typedef inode_t vnode_t;
+typedef struct page page_t;
+typedef struct qstr qstr_t;
+typedef struct super_block super_block_t;
+typedef super_block_t vfs_t;
+typedef struct vm_area_struct vm_area_t;
+
+
+/*
+ * EXTERNALS:
+ */
+
+#define FPPF(str,page) printk("PPF %s 0x%x/%d: Lck:%d Err:%d Ref:%d Upd:%d Other::%d:%d:%d:%d:\n", \
+               str, \
+               (int) page, \
+               (int) page->index, \
+               (PageLocked(page) ? 1 : 0), \
+               (PageError(page) ? 1 : 0), \
+               (PageReferenced(page) ? 1 : 0), \
+               (Page_Uptodate(page) ? 1 : 0), \
+               (PageDecrAfter(page) ? 1 : 0), \
+               (PageSlab(page) ? 1 : 0), \
+               (PageSwapCache(page) ? 1 : 0), \
+               (PageReserved(page) ? 1 : 0) \
+               )
+#define EZKDBG printk("EZK %s:%d:%s\n",__FILE__,__LINE__,__FUNCTION__)
+#if 0
+# define EZKDBG1 printk("EZK %s:%d\n",__FILE__,__LINE__)
+#else
+# define EZKDBG1
+#endif
+
+extern int fist_get_debug_value(void);
+extern int fist_set_debug_value(int val);
+#if 0 /* mini_fo doesn't need these */
+extern void fist_dprint_internal(int level, char *str,...);
+extern void fist_print_dentry(char *str, const dentry_t *dentry);
+extern void fist_print_inode(char *str, const inode_t *inode);
+extern void fist_print_file(char *str, const file_t *file);
+extern void fist_print_buffer_flags(char *str, struct buffer_head *buffer);
+extern void fist_print_page_flags(char *str, page_t *page);
+extern void fist_print_page_bytes(char *str, page_t *page);
+extern void fist_print_pte_flags(char *str, const page_t *page);
+extern void fist_checkinode(inode_t *inode, char *msg);
+extern void fist_print_sb(char *str, const super_block_t *sb);
+
+/* §$% by mk: special debug functions */
+extern void fist_mk_print_dentry(char *str, const dentry_t *dentry);
+extern void fist_mk_print_inode(char *str, const inode_t *inode);
+
+extern char *add_indent(void);
+extern char *del_indent(void);
+#endif/* mini_fo doesn't need these */
+
+
+#define STATIC
+#define ASSERT(EX)     \
+do {   \
+    if (!(EX)) {       \
+       printk(KERN_CRIT "ASSERTION FAILED: %s at %s:%d (%s)\n", #EX,   \
+              __FILE__, __LINE__, __FUNCTION__);       \
+       (*((char *)0))=0;       \
+    }  \
+} while (0)
+/* same ASSERT, but tell me who was the caller of the function */
+#define ASSERT2(EX)    \
+do {   \
+    if (!(EX)) {       \
+       printk(KERN_CRIT "ASSERTION FAILED (caller): %s at %s:%d (%s)\n", #EX,  \
+              file, line, func);       \
+       (*((char *)0))=0;       \
+    }  \
+} while (0)
+
+#if 0 /* mini_fo doesn't need these */
+#define dprintk(format, args...) printk(KERN_DEBUG format, ##args)
+#define fist_dprint(level, str, args...) fist_dprint_internal(level, KERN_DEBUG str, ## args)
+#define print_entry_location() fist_dprint(4, "%sIN:  %s %s:%d\n", add_indent(), __FUNCTION__, __FILE__, __LINE__)
+#define print_exit_location() fist_dprint(4, "%s OUT: %s %s:%d\n", del_indent(), __FUNCTION__, __FILE__, __LINE__)
+#define print_exit_status(status) fist_dprint(4, "%s OUT: %s %s:%d, STATUS: %d\n", del_indent(), __FUNCTION__, __FILE__, __LINE__, status)
+#define print_exit_pointer(status) \
+do { \
+  if (IS_ERR(status)) \
+    fist_dprint(4, "%s OUT: %s %s:%d, RESULT: %ld\n", del_indent(), __FUNCTION__, __FILE__, __LINE__, PTR_ERR(status)); \
+  else \
+    fist_dprint(4, "%s OUT: %s %s:%d, RESULT: 0x%x\n", del_indent(), __FUNCTION__, __FILE__, __LINE__, PTR_ERR(status)); \
+} while (0)
+#endif/* mini_fo doesn't need these */
+
+#endif /* __KERNEL__ */
+
+
+/*
+ * DEFINITIONS FOR USER AND KERNEL CODE:
+ * (Note: ioctl numbers 1--9 are reserved for fistgen, the rest
+ *  are auto-generated automatically based on the user's .fist file.)
+ */
+# define FIST_IOCTL_GET_DEBUG_VALUE    _IOR(0x15, 1, int)
+# define FIST_IOCTL_SET_DEBUG_VALUE    _IOW(0x15, 2, int)
+
+#endif /* not __FIST_H_ */
diff -urN linux-2.6.21.1.old/fs/mini_fo/inode.c linux-2.6.21.1.dev/fs/mini_fo/inode.c
--- linux-2.6.21.1.old/fs/mini_fo/inode.c       1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.21.1.dev/fs/mini_fo/inode.c       2007-05-26 21:01:26.164329720 +0200
@@ -0,0 +1,1573 @@
+/*
+ * Copyright (c) 1997-2003 Erez Zadok
+ * Copyright (c) 2001-2003 Stony Brook University
+ *
+ * For specific licensing information, see the COPYING file distributed with
+ * this package, or get one from ftp://ftp.filesystems.org/pub/fist/COPYING.
+ *
+ * This Copyright notice must be kept intact and distributed with all
+ * fistgen sources INCLUDING sources generated by fistgen.
+ */
+/*
+ * Copyright (C) 2004, 2005 Markus Klotzbuecher <mk@creamnet.de>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+/*
+ *  $Id$
+ */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif 
+
+#include "fist.h"
+#include "mini_fo.h"
+
+STATIC int
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
+mini_fo_create(inode_t *dir, dentry_t *dentry, int mode, struct nameidata *nd)
+#else
+mini_fo_create(inode_t *dir, dentry_t *dentry, int mode)
+#endif
+{
+       int err = 0;
+
+       check_mini_fo_dentry(dentry);
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
+       err = create_sto_reg_file(dentry, mode, nd);
+#else
+       err = create_sto_reg_file(dentry, mode);
+#endif
+       check_mini_fo_dentry(dentry);
+       return err;
+}
+
+
+STATIC dentry_t *
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
+mini_fo_lookup(inode_t *dir, dentry_t *dentry, struct nameidata* nd)
+#else
+mini_fo_lookup(inode_t *dir, dentry_t *dentry)
+#endif
+{
+       int err = 0;
+       dentry_t *hidden_dir_dentry;
+       dentry_t *hidden_dentry = NULL;
+
+       dentry_t *hidden_sto_dir_dentry;
+       dentry_t *hidden_sto_dentry = NULL;
+
+       /* whiteout flag */
+       int del_flag = 0; 
+       char *bpath = NULL;
+
+       const char *name;
+       unsigned int namelen;
+
+       /* Don't allow lookups of META-files */
+       namelen = strlen(META_FILENAME);
+       if(namelen == dentry->d_name.len) {
+               if(!strncmp(dentry->d_name.name, META_FILENAME, namelen)) {
+                       err = -ENOENT;
+                       goto out;
+               }
+       }
+
+       hidden_dir_dentry = dtohd(dentry->d_parent);
+       hidden_sto_dir_dentry = dtohd2(dentry->d_parent);
+
+       name = dentry->d_name.name;
+       namelen = dentry->d_name.len;
+
+       /* must initialize dentry operations */
+       dentry->d_op = &mini_fo_dops;
+
+       /* setup the del_flag */
+       del_flag = __meta_check_d_entry(dir, name, namelen);
+       bpath = __meta_check_r_entry(dir, name, namelen);
+
+       /* perform the lookups of base and storage files:
+        *
+        * This caused some serious trouble, as a lookup_one_len passing
+        * a negative dentry oopses. Solution is to only do the lookup
+        * if the dentry is positive, else we set it to NULL
+        * More trouble, who said a *_dir_dentry can't be NULL?
+        */
+       if(bpath) {
+               /* Cross-Interposing (C), yeah! */
+               hidden_dentry = bpath_walk(dir->i_sb, bpath);
+               if(!hidden_dentry || !hidden_dentry->d_inode) {
+                       printk(KERN_CRIT "mini_fo_lookup: bpath_walk failed.\n");
+                       err= -EINVAL;
+                       goto out;
+               }
+               
+               /* this can be set up safely without fear of spaghetti
+                * interposing as it is only used for copying times */
+               hidden_dir_dentry = hidden_dentry->d_parent;
+               kfree(bpath);
+       }
+       else if(hidden_dir_dentry && hidden_dir_dentry->d_inode)
+               hidden_dentry = 
+                       lookup_one_len(name, hidden_dir_dentry, namelen);
+       else
+               hidden_dentry = NULL;
+
+       if(hidden_sto_dir_dentry && hidden_sto_dir_dentry->d_inode)
+               hidden_sto_dentry = 
+                       lookup_one_len(name, hidden_sto_dir_dentry, namelen);
+       else
+               hidden_sto_dentry =  NULL;
+
+       /* catch error in lookup */
+       if (IS_ERR(hidden_dentry) || IS_ERR(hidden_sto_dentry)) {
+               /* mk: we need to call dput on the dentry, whose 
+                * lookup_one_len operation failed, in order to avoid
+                * unmount trouble.
+                */
+               if(IS_ERR(hidden_dentry)) {
+                       printk(KERN_CRIT "mini_fo_lookup: ERR from base dentry, lookup failed.\n");
+                       err = PTR_ERR(hidden_dentry);
+               } else {
+                       dput(hidden_dentry);
+               }
+               if(IS_ERR(hidden_sto_dentry)) {
+                       printk(KERN_CRIT "mini_fo_lookup: ERR from storage dentry, lookup failed.\n");
+                       err = PTR_ERR(hidden_sto_dentry);
+               } else {
+                       dput(hidden_sto_dentry);
+               }
+               goto out;
+       }
+
+       /* allocate dentry private data */
+       __dtopd(dentry) = (struct mini_fo_dentry_info *)
+               kmalloc(sizeof(struct mini_fo_dentry_info), GFP_KERNEL);
+       
+       if (!dtopd(dentry)) {
+               err = -ENOMEM;
+               goto out_dput;
+       }
+
+       /* check for different states of the mini_fo file to be looked up. */
+       
+       /* state 1, file has been modified */
+       if(hidden_dentry && hidden_sto_dentry &&
+          hidden_dentry->d_inode && hidden_sto_dentry->d_inode && !del_flag) {
+
+               /* update parent directory's atime */
+               fist_copy_attr_atime(dir, hidden_sto_dir_dentry->d_inode);
+
+               dtopd(dentry)->state = MODIFIED;
+               dtohd(dentry) = hidden_dentry;
+               dtohd2(dentry) = hidden_sto_dentry;
+
+               err = mini_fo_tri_interpose(hidden_dentry,
+                                           hidden_sto_dentry,
+                                           dentry, dir->i_sb, 1);
+               if (err) {
+                       printk(KERN_CRIT "mini_fo_lookup: error interposing (state1).\n");
+                       goto out_free;
+               }
+               goto out;
+       }
+       /* state 2, file is unmodified */
+       if(hidden_dentry && hidden_dentry->d_inode && !del_flag) {
+
+               fist_copy_attr_atime(dir, hidden_dir_dentry->d_inode);
+
+               dtopd(dentry)->state = UNMODIFIED;
+               dtohd(dentry) = hidden_dentry;
+               dtohd2(dentry) = hidden_sto_dentry; /* could be negative */
+
+               err = mini_fo_tri_interpose(hidden_dentry,
+                                           hidden_sto_dentry,
+                                           dentry, dir->i_sb, 1);
+               if (err) {
+                       printk(KERN_CRIT "mini_fo_lookup: error interposing (state2).\n");
+                       goto out_free;
+               }
+               goto out;
+       }
+       /* state 3, file has been newly created */
+       if(hidden_sto_dentry && hidden_sto_dentry->d_inode && !del_flag) {
+
+               fist_copy_attr_atime(dir, hidden_sto_dir_dentry->d_inode);
+               dtopd(dentry)->state = CREATED;
+               dtohd(dentry) = hidden_dentry; /* could be negative */
+               dtohd2(dentry) = hidden_sto_dentry;
+
+               err = mini_fo_tri_interpose(hidden_dentry,
+                                           hidden_sto_dentry,
+                                           dentry, dir->i_sb, 1);
+               if (err) {
+                       printk(KERN_CRIT "mini_fo_lookup: error interposing (state3).\n");
+                       goto out_free;
+               }
+               goto out;
+       }
+
+       /* state 4, file has deleted and created again. */
+       if(hidden_dentry && hidden_sto_dentry &&
+          hidden_dentry->d_inode && 
+          hidden_sto_dentry->d_inode && del_flag) {
+
+               fist_copy_attr_atime(dir, hidden_sto_dir_dentry->d_inode);
+               dtopd(dentry)->state = DEL_REWRITTEN;
+               dtohd(dentry) = NULL;
+               dtohd2(dentry) = hidden_sto_dentry;
+
+               err = mini_fo_tri_interpose(NULL,
+                                           hidden_sto_dentry,
+                                           dentry, dir->i_sb, 1);
+               if (err) {
+                       printk(KERN_CRIT "mini_fo_lookup: error interposing (state4).\n");
+                       goto out_free;
+               }
+               /* We will never need this dentry again, as the file has been
+                * deleted from base */
+               dput(hidden_dentry);
+               goto out;
+       }
+       /* state 5, file has been deleted in base */
+       if(hidden_dentry && hidden_sto_dentry &&
+          hidden_dentry->d_inode && 
+          !hidden_sto_dentry->d_inode && del_flag) {
+
+               /* check which parents atime we need for updating */
+               if(hidden_sto_dir_dentry->d_inode)
+                       fist_copy_attr_atime(dir, 
+                                            hidden_sto_dir_dentry->d_inode);
+               else
+                       fist_copy_attr_atime(dir, 
+                                            hidden_dir_dentry->d_inode);
+
+               dtopd(dentry)->state = DELETED;
+               dtohd(dentry) = NULL;
+               dtohd2(dentry) = hidden_sto_dentry;
+
+               /* add negative dentry to dcache to speed up lookups */
+               d_add(dentry, NULL);
+               dput(hidden_dentry);
+               goto out;
+       }
+       /* state 6, file does not exist */
+       if(((hidden_dentry && !hidden_dentry->d_inode) ||
+           (hidden_sto_dentry && !hidden_sto_dentry->d_inode)) && !del_flag)
+               {
+                       /* check which parents atime we need for updating */
+                       if(hidden_sto_dir_dentry && hidden_sto_dir_dentry->d_inode)
+                               fist_copy_attr_atime(dir, hidden_sto_dir_dentry->d_inode);
+                       else
+                               fist_copy_attr_atime(dir, hidden_dir_dentry->d_inode);
+
+                       dtopd(dentry)->state = NON_EXISTANT;
+                       dtohd(dentry) = hidden_dentry;
+                       dtohd2(dentry) = hidden_sto_dentry;
+                       d_add(dentry, NULL);
+                       goto out;
+               }
+
+       /* if we get to here, were in an invalid state. bad. */
+       printk(KERN_CRIT "mini_fo_lookup: ERROR, meta data corruption detected.\n");
+
+       /* end state checking */
+ out_free:
+       d_drop(dentry);         /* so that our bad dentry will get destroyed */
+       kfree(dtopd(dentry));
+       __dtopd(dentry) = NULL; /* be safe */
+
+ out_dput:
+       if(hidden_dentry)
+               dput(hidden_dentry);
+       if(hidden_sto_dentry)
+               dput(hidden_sto_dentry); /* drops usage count and marks for release */
+
+ out:
+       /* initalize wol if file exists and is directory */
+       if(dentry->d_inode) {
+               if(S_ISDIR(dentry->d_inode->i_mode)) {
+                       itopd(dentry->d_inode)->deleted_list_size = -1;
+                       itopd(dentry->d_inode)->renamed_list_size = -1;
+                       meta_build_lists(dentry);
+               }
+       }
+       return ERR_PTR(err);
+}
+
+
+STATIC int
+mini_fo_link(dentry_t *old_dentry, inode_t *dir, dentry_t *new_dentry)
+{
+       int err;
+       dentry_t *hidden_old_dentry;
+       dentry_t *hidden_new_dentry;
+       dentry_t *hidden_dir_dentry;
+
+
+       check_mini_fo_dentry(old_dentry);
+       check_mini_fo_dentry(new_dentry);
+       check_mini_fo_inode(dir);
+
+       /* no links to directorys and existing targets target allowed */
+       if(S_ISDIR(old_dentry->d_inode->i_mode) ||
+          is_mini_fo_existant(new_dentry)) {
+               err = -EPERM;
+               goto out;
+       }
+
+       /* bring it directly from unmod to del_rew */
+       if(dtost(old_dentry) == UNMODIFIED) {
+               err = nondir_unmod_to_mod(old_dentry, 1);
+               if(err) {
+                       err = -EINVAL;
+                       goto out;
+               }
+               err = meta_add_d_entry(old_dentry->d_parent,
+                                      old_dentry->d_name.name,
+                                      old_dentry->d_name.len);
+               if(err) {
+                       err = -EINVAL;
+                       goto out;
+               }
+               dput(dtohd(old_dentry));
+               dtohd(old_dentry) = NULL;
+               dtost(old_dentry) = DEL_REWRITTEN;
+       }
+       
+       err = get_neg_sto_dentry(new_dentry);
+       if(err) {
+               err = -EINVAL;
+               goto out;
+       }
+
+       hidden_old_dentry = dtohd2(old_dentry);
+       hidden_new_dentry = dtohd2(new_dentry);
+
+       dget(hidden_old_dentry);
+       dget(hidden_new_dentry);
+
+       /* was: hidden_dir_dentry = lock_parent(hidden_new_dentry); */
+       hidden_dir_dentry = dget(hidden_new_dentry->d_parent);
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
+       mutex_lock(&hidden_dir_dentry->d_inode->i_mutex);
+#else
+       down(&hidden_dir_dentry->d_inode->i_sem);
+#endif
+
+       err = vfs_link(hidden_old_dentry,
+                      hidden_dir_dentry->d_inode,
+                      hidden_new_dentry);
+       if (err || !hidden_new_dentry->d_inode)
+               goto out_lock;
+
+       dtost(new_dentry) = CREATED;
+       err = mini_fo_tri_interpose(NULL, hidden_new_dentry, new_dentry, dir->i_sb, 0);
+       if (err)
+               goto out_lock;
+
+       fist_copy_attr_timesizes(dir, hidden_new_dentry->d_inode);
+       /* propagate number of hard-links */
+       old_dentry->d_inode->i_nlink = itohi2(old_dentry->d_inode)->i_nlink;
+
+ out_lock:
+       /* was: unlock_dir(hidden_dir_dentry); */
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
+       mutex_unlock(&hidden_dir_dentry->d_inode->i_mutex);
+#else
+       up(&hidden_dir_dentry->d_inode->i_sem);
+#endif
+       dput(hidden_dir_dentry);
+
+       dput(hidden_new_dentry);
+       dput(hidden_old_dentry);
+       if (!new_dentry->d_inode)
+               d_drop(new_dentry);
+
+ out:
+       return err;
+}
+
+
+STATIC int
+mini_fo_unlink(inode_t *dir, dentry_t *dentry)
+{
+       int err = 0;
+
+       dget(dentry);
+       if(dtopd(dentry)->state == MODIFIED) {
+               err = nondir_mod_to_del(dentry);
+               goto out;
+       }
+       else if(dtopd(dentry)->state == UNMODIFIED) {
+               err = nondir_unmod_to_del(dentry);
+               goto out;
+       }
+       else if(dtopd(dentry)->state == CREATED) {
+               err = nondir_creat_to_del(dentry);
+               goto out;
+       }
+       else if(dtopd(dentry)->state == DEL_REWRITTEN) {
+               err = nondir_del_rew_to_del(dentry);
+               goto out;
+       }
+
+       printk(KERN_CRIT "mini_fo_unlink: ERROR, invalid state detected.\n");
+
+ out:
+       fist_copy_attr_times(dir, itohi2(dentry->d_parent->d_inode));
+
+       if(!err) {
+               /* is this causing my pain? d_delete(dentry); */
+               d_drop(dentry);
+       }
+
+       dput(dentry);
+       return err;
+}
+
+
+STATIC int
+mini_fo_symlink(inode_t *dir, dentry_t *dentry, const char *symname)
+{
+       int err=0;
+       dentry_t *hidden_sto_dentry;
+       dentry_t *hidden_sto_dir_dentry;
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
+        umode_t mode;
+#endif
+
+       /* Fail if the symlink file exists */
+       if(!(dtost(dentry) == DELETED || 
+            dtost(dentry) == NON_EXISTANT)) {
+               err = -EEXIST;
+               goto out;
+       }
+
+       err = get_neg_sto_dentry(dentry);
+       if(err) {
+               err = -EINVAL;
+               goto out;
+       }
+       hidden_sto_dentry = dtohd2(dentry);
+
+       dget(hidden_sto_dentry);
+       /* was: hidden_sto_dir_dentry = lock_parent(hidden_sto_dentry); */
+       hidden_sto_dir_dentry = dget(hidden_sto_dentry->d_parent);
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
+       mutex_lock(&hidden_sto_dir_dentry->d_inode->i_mutex);
+#else
+       down(&hidden_sto_dir_dentry->d_inode->i_sem);
+#endif
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
+       mode = S_IALLUGO;
+       err = vfs_symlink(hidden_sto_dir_dentry->d_inode,
+                         hidden_sto_dentry, symname, mode);
+#else
+       err = vfs_symlink(hidden_sto_dir_dentry->d_inode,
+                         hidden_sto_dentry,
+                         symname);
+#endif
+       if (err || !hidden_sto_dentry->d_inode)
+                goto out_lock;
+
+        if(dtost(dentry) == DELETED) {
+                dtost(dentry) = DEL_REWRITTEN;
+                err = mini_fo_tri_interpose(NULL, hidden_sto_dentry, dentry, dir->i_sb, 0);
+                if(err)
+                        goto out_lock;
+        } else if(dtost(dentry) == NON_EXISTANT) {
+                dtost(dentry) = CREATED;
+                err = mini_fo_tri_interpose(dtohd(dentry), hidden_sto_dentry, dentry, dir->i_sb, 0);
+                if(err)
+                        goto out_lock;
+        }
+       fist_copy_attr_timesizes(dir, hidden_sto_dir_dentry->d_inode);
+       
+ out_lock:
+        /* was: unlock_dir(hidden_sto_dir_dentry); */
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
+       mutex_unlock(&hidden_sto_dir_dentry->d_inode->i_mutex);
+#else
+       up(&hidden_sto_dir_dentry->d_inode->i_sem);
+#endif
+       dput(hidden_sto_dir_dentry);
+
+        dput(hidden_sto_dentry);
+        if (!dentry->d_inode)
+                d_drop(dentry);
+ out:
+        return err;
+}
+
+STATIC int
+mini_fo_mkdir(inode_t *dir, dentry_t *dentry, int mode)
+{
+       int err;
+
+       err = create_sto_dir(dentry, mode);
+
+       check_mini_fo_dentry(dentry);
+
+       return err;
+}
+
+
+STATIC int
+mini_fo_rmdir(inode_t *dir, dentry_t *dentry)
+{
+       int err = 0;
+       
+       dentry_t *hidden_sto_dentry;
+       dentry_t *hidden_sto_dir_dentry;
+       dentry_t *meta_dentry;
+       inode_t *hidden_sto_dir = NULL;
+
+       check_mini_fo_dentry(dentry);
+       check_mini_fo_inode(dir);
+
+       dget(dentry);
+       if(dtopd(dentry)->state == MODIFIED) {
+               /* XXX: disabled, because it does not bother to check files on
+                * the original filesystem - just a hack, but better than simply
+                * removing it without testing */
+               err = -EINVAL;
+               goto out;
+
+               hidden_sto_dir = itohi2(dir);
+               hidden_sto_dentry = dtohd2(dentry);
+
+               /* was:hidden_sto_dir_dentry = lock_parent(hidden_sto_dentry); */
+               hidden_sto_dir_dentry = dget(hidden_sto_dentry->d_parent);
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
+               mutex_lock(&hidden_sto_dir_dentry->d_inode->i_mutex);
+#else
+               down(&hidden_sto_dir_dentry->d_inode->i_sem);
+#endif
+
+               /* avoid destroying the hidden inode if the file is in use */
+               dget(hidden_sto_dentry);
+
+               /* Delete an old WOL file contained in the storage dir */
+               meta_dentry = lookup_one_len(META_FILENAME, 
+                                            hidden_sto_dentry, 
+                                            strlen(META_FILENAME));
+               if(meta_dentry->d_inode) {
+                       err = vfs_unlink(hidden_sto_dentry->d_inode, meta_dentry);
+                       dput(meta_dentry);
+                       if(!err)
+                               d_delete(meta_dentry);
+               }
+
+               err = vfs_rmdir(hidden_sto_dir, hidden_sto_dentry);
+               dput(hidden_sto_dentry);
+               if(!err)
+                       d_delete(hidden_sto_dentry);
+
+               /* propagate number of hard-links */
+               dentry->d_inode->i_nlink = itohi2(dentry->d_inode)->i_nlink;
+
+               dput(dtohd(dentry));
+               
+               dtohd(dentry) = NULL;
+               dtopd(dentry)->state = DELETED;
+
+               /* carefull with R files */
+               if( __meta_is_r_entry(dir, 
+                                     dentry->d_name.name, 
+                                     dentry->d_name.len) == 1) {
+                       err = meta_remove_r_entry(dentry->d_parent, 
+                                                 dentry->d_name.name,
+                                                 dentry->d_name.len);
+                       if(err) {
+                               printk(KERN_CRIT "mini_fo: rmdir: meta_remove_r_entry failed.\n");
+                               goto out;
+                       }
+               }
+               else {
+                       /* ok, add deleted file to META */              
+                       meta_add_d_entry(dentry->d_parent, 
+                                        dentry->d_name.name, 
+                                        dentry->d_name.len);
+               }
+               /* was: unlock_dir(hidden_sto_dir_dentry); */
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
+               mutex_unlock(&hidden_sto_dir_dentry->d_inode->i_mutex);
+#else
+               up(&hidden_sto_dir_dentry->d_inode->i_sem);
+#endif
+               dput(hidden_sto_dir_dentry);
+               goto out;
+       }
+       else if(dtopd(dentry)->state == UNMODIFIED) {
+               /* XXX: simply adding it to the delete list here is fscking dangerous!
+                * as a temporary hack, i will disable rmdir on unmodified directories 
+                * for now.
+                */
+               err = -EINVAL;
+               goto out;
+
+               err = get_neg_sto_dentry(dentry);
+               if(err) {
+                       err = -EINVAL;
+                       goto out;
+               }
+               
+               /* dput base dentry, this will relase the inode and free the
+                * dentry, as we will never need it again. */
+               dput(dtohd(dentry));
+               dtohd(dentry) = NULL;
+               dtopd(dentry)->state = DELETED;
+
+               /* add deleted file to META-file */
+               meta_add_d_entry(dentry->d_parent, 
+                                dentry->d_name.name, 
+                                dentry->d_name.len);
+               goto out;
+       }
+       else if(dtopd(dentry)->state == CREATED) {
+               hidden_sto_dir = itohi2(dir);
+               hidden_sto_dentry = dtohd2(dentry);
+
+               /* was: hidden_sto_dir_dentry = lock_parent(hidden_sto_dentry);*/
+               hidden_sto_dir_dentry = dget(hidden_sto_dentry->d_parent);
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
+               mutex_lock(&hidden_sto_dir_dentry->d_inode->i_mutex);
+#else
+               down(&hidden_sto_dir_dentry->d_inode->i_sem);
+#endif
+
+               /* avoid destroying the hidden inode if the file is in use */
+               dget(hidden_sto_dentry);
+
+               /* Delete an old WOL file contained in the storage dir */
+               meta_dentry = lookup_one_len(META_FILENAME, 
+                                            hidden_sto_dentry, 
+                                            strlen(META_FILENAME));
+               if(meta_dentry->d_inode) {
+                       /* is this necessary? dget(meta_dentry); */
+                       err = vfs_unlink(hidden_sto_dentry->d_inode, 
+                                        meta_dentry);
+                       dput(meta_dentry);
+                       if(!err)
+                               d_delete(meta_dentry);
+               }
+
+               err = vfs_rmdir(hidden_sto_dir, hidden_sto_dentry);
+               dput(hidden_sto_dentry);
+               if(!err)
+                       d_delete(hidden_sto_dentry);
+
+               /* propagate number of hard-links */
+               dentry->d_inode->i_nlink = itohi2(dentry->d_inode)->i_nlink;
+               dtopd(dentry)->state = NON_EXISTANT;
+
+               /* was: unlock_dir(hidden_sto_dir_dentry); */
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
+               mutex_unlock(&hidden_sto_dir_dentry->d_inode->i_mutex);
+#else
+               up(&hidden_sto_dir_dentry->d_inode->i_sem);
+#endif
+               dput(hidden_sto_dir_dentry);
+
+               goto out;
+       }
+       else if(dtopd(dentry)->state == DEL_REWRITTEN) {
+               hidden_sto_dir = itohi2(dir);
+               hidden_sto_dentry = dtohd2(dentry);
+
+               /* was: hidden_sto_dir_dentry = lock_parent(hidden_sto_dentry);*/
+               hidden_sto_dir_dentry = dget(hidden_sto_dentry->d_parent);
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
+               mutex_lock(&hidden_sto_dir_dentry->d_inode->i_mutex);
+#else
+               down(&hidden_sto_dir_dentry->d_inode->i_sem);
+#endif
+
+               /* avoid destroying the hidden inode if the file is in use */
+               dget(hidden_sto_dentry);
+
+               /* Delete an old WOL file contained in the storage dir */
+               meta_dentry = lookup_one_len(META_FILENAME, 
+                                            hidden_sto_dentry, 
+                                            strlen(META_FILENAME));
+               if(meta_dentry->d_inode) {
+                       /* is this necessary? dget(meta_dentry); */
+                       err = vfs_unlink(hidden_sto_dentry->d_inode,
+                                        meta_dentry);
+                       dput(meta_dentry);
+                       if(!err)
+                               d_delete(meta_dentry);
+               }
+
+               err = vfs_rmdir(hidden_sto_dir, hidden_sto_dentry);
+               dput(hidden_sto_dentry);
+               if(!err)
+                       d_delete(hidden_sto_dentry);
+
+               /* propagate number of hard-links */
+               dentry->d_inode->i_nlink = itohi2(dentry->d_inode)->i_nlink;
+               dtopd(dentry)->state = DELETED;
+               /* was: unlock_dir(hidden_sto_dir_dentry); */
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
+               mutex_unlock(&hidden_sto_dir_dentry->d_inode->i_mutex);
+#else
+               up(&hidden_sto_dir_dentry->d_inode->i_sem);
+#endif
+               dput(hidden_sto_dir_dentry);
+               goto out;
+       }
+
+       printk(KERN_CRIT "mini_fo_rmdir: ERROR, invalid state detected.\n");
+
+ out:
+       if(!err) {
+               d_drop(dentry);
+       }
+               
+       fist_copy_attr_times(dir, itohi2(dentry->d_parent->d_inode));
+       dput(dentry);
+
+       return err;
+}
+
+
+STATIC int
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
+mini_fo_mknod(inode_t *dir, dentry_t *dentry, int mode, dev_t dev)
+#else
+mini_fo_mknod(inode_t *dir, dentry_t *dentry, int mode, int dev)
+#endif
+{
+       int err = 0;
+
+       check_mini_fo_dentry(dentry);
+
+       err = create_sto_nod(dentry, mode, dev);
+       if(err) {
+               printk(KERN_CRIT "mini_fo_mknod: creating sto nod failed.\n");
+               err = -EINVAL;
+       }
+       
+       check_mini_fo_dentry(dentry);
+       return err;
+}
+
+
+STATIC int
+mini_fo_rename(inode_t *old_dir, dentry_t *old_dentry,
+              inode_t *new_dir, dentry_t *new_dentry)
+{
+       /* dispatch */
+       if(S_ISDIR(old_dentry->d_inode->i_mode))
+               return rename_directory(old_dir, old_dentry, new_dir, new_dentry);
+       return rename_nondir(old_dir, old_dentry, new_dir, new_dentry);
+       
+}
+
+int rename_directory(inode_t *old_dir, dentry_t *old_dentry,
+                    inode_t *new_dir, dentry_t *new_dentry)
+{
+       int err, bpath_len;
+       char *bpath;
+
+       dentry_t *hidden_old_dentry;
+       dentry_t *hidden_new_dentry;
+       dentry_t *hidden_old_dir_dentry;
+       dentry_t *hidden_new_dir_dentry;
+
+       err = 0;
+       bpath = NULL;
+       bpath_len = 0;
+
+       /* this is a test, chuck out if it works */
+       if(!(dtopd(new_dentry)->state == DELETED ||
+            dtopd(new_dentry)->state == NON_EXISTANT)) {
+               printk(KERN_CRIT "mini_fo: rename_directory: \
+                                  uh, ah, new_dentry not negative.\n");
+               /* return -1; */
+       }
+       
+       /* state = UNMODIFIED */
+       if(dtopd(old_dentry)->state == UNMODIFIED) {
+               err = dir_unmod_to_mod(old_dentry);
+               if (err) 
+                       goto out;
+       }
+
+       /* state = MODIFIED */
+       if(dtopd(old_dentry)->state == MODIFIED) {
+               bpath = meta_check_r_entry(old_dentry->d_parent, 
+                                          old_dentry->d_name.name,
+                                          old_dentry->d_name.len);
+               if(bpath) {
+                       err = meta_remove_r_entry(old_dentry->d_parent,
+                                                 old_dentry->d_name.name,
+                                                 old_dentry->d_name.len);
+                       if(err) {
+                               printk(KERN_CRIT "mini_fo: rename_directory:\
+                                                   meta_remove_r_entry \
+                                                  failed.\n");
+                               goto out;
+                       }
+                       err = meta_add_r_entry(new_dentry->d_parent,
+                                              bpath,
+                                              strlen(bpath),
+                                              new_dentry->d_name.name,
+                                              new_dentry->d_name.len);
+                       kfree(bpath);
+               }
+               else {/* wol it */
+                       err = meta_add_d_entry(old_dentry->d_parent, 
+                                              old_dentry->d_name.name,
+                                              old_dentry->d_name.len);
+                       if (err) 
+                               goto out;
+                       /* put it on rename list */
+                       err = get_mini_fo_bpath(old_dentry,
+                                               &bpath, 
+                                               &bpath_len);
+                       if (err) 
+                               goto out;
+                       err = meta_add_r_entry(new_dentry->d_parent,
+                                              bpath, bpath_len,
+                                              new_dentry->d_name.name,
+                                              new_dentry->d_name.len);
+                       if (err) 
+                               goto out;
+               }
+               /* no state change, MODIFIED stays MODIFIED */
+       }
+       /* state = CREATED */
+       if(dtopd(old_dentry)->state == CREATED ||
+          dtopd(old_dentry)->state == DEL_REWRITTEN) {
+               if(dtohd(old_dentry))
+                       dput(dtohd(old_dentry));
+               
+               if(dtopd(new_dentry)->state == DELETED) {
+                       dtopd(old_dentry)->state = DEL_REWRITTEN;
+                       dtohd(old_dentry) = NULL;
+               } 
+               else if(dtopd(new_dentry)->state == NON_EXISTANT) {
+                       dtopd(old_dentry)->state = CREATED;
+                       /* steal new dentry's neg. base dentry */
+                       dtohd(old_dentry) = dtohd(new_dentry);
+                       dtohd(new_dentry) = NULL;
+               }
+       }               
+       if(dtopd(new_dentry)->state == UNMODIFIED ||
+          dtopd(new_dentry)->state == NON_EXISTANT) {
+               err = get_neg_sto_dentry(new_dentry);
+               if(err)
+                       goto out;
+       }
+                       
+       /* now move sto file */
+       hidden_old_dentry = dtohd2(old_dentry);
+       hidden_new_dentry = dtohd2(new_dentry);
+       
+       dget(hidden_old_dentry);
+       dget(hidden_new_dentry);
+       
+       hidden_old_dir_dentry = dget(hidden_old_dentry->d_parent);
+       hidden_new_dir_dentry = dget(hidden_new_dentry->d_parent);
+       double_lock(hidden_old_dir_dentry, hidden_new_dir_dentry);
+       
+       err = vfs_rename(hidden_old_dir_dentry->d_inode, hidden_old_dentry,
+                        hidden_new_dir_dentry->d_inode, hidden_new_dentry);
+       if(err)
+               goto out_lock;
+       
+       fist_copy_attr_all(new_dir, hidden_new_dir_dentry->d_inode);
+       if (new_dir != old_dir)
+               fist_copy_attr_all(old_dir, 
+                                  hidden_old_dir_dentry->d_inode);
+       
+ out_lock:
+       /* double_unlock will dput the new/old parent dentries
+        * whose refcnts were incremented via get_parent above. */
+       double_unlock(hidden_old_dir_dentry, hidden_new_dir_dentry);
+       dput(hidden_new_dentry);
+       dput(hidden_old_dentry);
+       
+ out:
+       return err;
+}
+
+int rename_nondir(inode_t *old_dir, dentry_t *old_dentry,
+                 inode_t *new_dir, dentry_t *new_dentry)
+{
+       int err=0;
+
+       check_mini_fo_dentry(old_dentry);
+       check_mini_fo_dentry(new_dentry);
+       check_mini_fo_inode(old_dir);
+       check_mini_fo_inode(new_dir);
+
+       /* state: UNMODIFIED */
+       if(dtost(old_dentry) == UNMODIFIED) {
+               err = nondir_unmod_to_mod(old_dentry, 1);
+               if(err) {
+                       err = -EINVAL;
+                       goto out;
+               }
+       }
+
+       /* the easy states */
+       if(exists_in_storage(old_dentry)) {
+               
+               dentry_t *hidden_old_dentry;
+               dentry_t *hidden_new_dentry;
+               dentry_t *hidden_old_dir_dentry;
+               dentry_t *hidden_new_dir_dentry;
+
+               /* if old file is MODIFIED, add it to the deleted_list */
+               if(dtopd(old_dentry)->state == MODIFIED) {
+                       meta_add_d_entry(old_dentry->d_parent,
+                                        old_dentry->d_name.name,
+                                        old_dentry->d_name.len);
+
+                       dput(dtohd(old_dentry));
+               }
+               /* if old file is CREATED, we only release the base dentry */
+               if(dtopd(old_dentry)->state == CREATED) {
+                       if(dtohd(old_dentry))
+                               dput(dtohd(old_dentry));
+               }
+
+               /* now setup the new states (depends on new_dentry state) */
+               /* new dentry state =  MODIFIED */
+               if(dtopd(new_dentry)->state == MODIFIED) {
+                       meta_add_d_entry(new_dentry->d_parent,
+                                        new_dentry->d_name.name,
+                                        new_dentry->d_name.len);
+
+                       /* new dentry will be d_put'ed later by the vfs
+                        * so don't do it here
+                        * dput(dtohd(new_dentry));
+                        */
+                       dtohd(old_dentry) = NULL;
+                       dtopd(old_dentry)->state = DEL_REWRITTEN;
+               }
+               /* new dentry state =  UNMODIFIED */
+               else if(dtopd(new_dentry)->state == UNMODIFIED) {
+                       if(get_neg_sto_dentry(new_dentry))
+                               return -EINVAL;
+
+                       meta_add_d_entry(new_dentry->d_parent,
+                                        new_dentry->d_name.name,
+                                        new_dentry->d_name.len);
+
+                       /* is this right??? */
+                       /*dput(dtohd(new_dentry));*/
+                       dtohd(old_dentry) = NULL;
+                       dtopd(old_dentry)->state = DEL_REWRITTEN;
+               }
+               /* new dentry state =  CREATED */
+               else if(dtopd(new_dentry)->state == CREATED) {
+                       /* we keep the neg. base dentry (if exists) */
+                       dtohd(old_dentry) = dtohd(new_dentry);
+                       /* ...and set it to Null, or we'll get
+                        * dcache.c:345 if it gets dput twice... */
+                       dtohd(new_dentry) = NULL;
+                       dtopd(old_dentry)->state = CREATED;
+               }
+               /* new dentry state =  NON_EXISTANT */
+               else if(dtopd(new_dentry)->state == NON_EXISTANT) {
+                       if(get_neg_sto_dentry(new_dentry))
+                               return -EINVAL;
+
+                       /* we keep the neg. base dentry (if exists) */
+                       dtohd(old_dentry) = dtohd(new_dentry);
+                       /* ...and set it to Null, or we'll get 
+                        * Dr. dcache.c:345 if it gets dput twice... */
+                       dtohd(new_dentry) = NULL;
+                       dtopd(old_dentry)->state = CREATED;
+               }
+               /* new dentry state =  DEL_REWRITTEN or DELETED */
+               else if(dtopd(new_dentry)->state == DEL_REWRITTEN ||
+                       dtopd(new_dentry)->state == DELETED) {
+                       dtohd(old_dentry) = NULL;
+                       dtopd(old_dentry)->state = DEL_REWRITTEN;
+               }
+               else { /* not possible, uhh, ahh */
+                       printk(KERN_CRIT 
+                              "mini_fo: rename_reg_file: invalid state detected [1].\n");
+                       return -1;
+               }
+               
+               /* now we definitely have a sto file */
+               hidden_old_dentry = dtohd2(old_dentry);
+               hidden_new_dentry = dtohd2(new_dentry);
+
+               dget(hidden_old_dentry);
+               dget(hidden_new_dentry);
+               
+               hidden_old_dir_dentry = dget(hidden_old_dentry->d_parent);
+               hidden_new_dir_dentry = dget(hidden_new_dentry->d_parent);
+               double_lock(hidden_old_dir_dentry, hidden_new_dir_dentry);
+
+               err = vfs_rename(hidden_old_dir_dentry->d_inode, 
+                                hidden_old_dentry,
+                                hidden_new_dir_dentry->d_inode, 
+                                hidden_new_dentry);
+               if(err) 
+                       goto out_lock;
+
+               fist_copy_attr_all(new_dir, hidden_new_dir_dentry->d_inode);
+               if (new_dir != old_dir)
+                       fist_copy_attr_all(old_dir, hidden_old_dir_dentry->d_inode);
+               
+       out_lock:
+               /* double_unlock will dput the new/old parent dentries 
+                * whose refcnts were incremented via get_parent above.
+                */
+               double_unlock(hidden_old_dir_dentry, hidden_new_dir_dentry);
+               dput(hidden_new_dentry);
+               dput(hidden_old_dentry);
+       out:            
+               return err;
+       }
+       else { /* invalid state */
+               printk(KERN_CRIT "mini_fo: rename_reg_file: ERROR: invalid state detected [2].\n");
+               return -1;
+       }
+}
+
+
+STATIC int
+mini_fo_readlink(dentry_t *dentry, char *buf, int bufsiz)
+{
+       int err=0;
+       dentry_t *hidden_dentry = NULL;
+
+       if(dtohd2(dentry) && dtohd2(dentry)->d_inode) {
+               hidden_dentry = dtohd2(dentry);
+       } else if(dtohd(dentry) && dtohd(dentry)->d_inode) {
+               hidden_dentry = dtohd(dentry);
+       } else {
+               goto out;
+       }
+
+       if (!hidden_dentry->d_inode->i_op ||
+           !hidden_dentry->d_inode->i_op->readlink) {
+               err = -EINVAL;          goto out;
+       }
+
+       err = hidden_dentry->d_inode->i_op->readlink(hidden_dentry,
+                                                    buf,
+                                                    bufsiz);
+       if (err > 0)
+               fist_copy_attr_atime(dentry->d_inode, hidden_dentry->d_inode);
+
+ out:
+       return err;
+}
+
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,13)
+static int mini_fo_follow_link(dentry_t *dentry, struct nameidata *nd)
+#else
+static void* mini_fo_follow_link(dentry_t *dentry, struct nameidata *nd)
+#endif
+{
+       char *buf;
+       int len = PAGE_SIZE, err;
+       mm_segment_t old_fs;
+
+       /* in 2.6 this is freed by mini_fo_put_link called by __do_follow_link */
+       buf = kmalloc(len, GFP_KERNEL);
+       if (!buf) {
+               err = -ENOMEM;
+               goto out;
+       }
+
+       /* read the symlink, and then we will follow it */
+       old_fs = get_fs();
+       set_fs(KERNEL_DS);
+       err = dentry->d_inode->i_op->readlink(dentry, buf, len);
+       set_fs(old_fs);
+       if (err < 0) {
+               kfree(buf);
+               buf = NULL;
+               goto out;
+       }
+       buf[err] = 0;
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
+        nd_set_link(nd, buf);
+        err = 0;
+#else
+       err = vfs_follow_link(nd, buf);
+#endif
+
+ out:
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
+       kfree(buf);
+#endif
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,13)
+        return err;
+#else
+        return ERR_PTR(err);
+#endif
+}
+
+STATIC
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,13)
+void mini_fo_put_link(struct dentry *dentry, struct nameidata *nd)
+#else
+void mini_fo_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie)
+#endif
+{
+        char *link;
+        link = nd_get_link(nd);
+        kfree(link);
+}
+#endif
+
+STATIC int
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
+mini_fo_permission(inode_t *inode, int mask, struct nameidata *nd)
+#else
+mini_fo_permission(inode_t *inode, int mask)
+#endif
+{
+       inode_t *hidden_inode;
+       int mode;
+       int err;
+
+       if(itohi2(inode)) {
+               hidden_inode = itohi2(inode);
+       } else {
+               hidden_inode = itohi(inode);
+       }
+       mode = inode->i_mode;
+
+       /* not really needed, as permission handles everything:
+        *      err = vfs_permission(inode, mask);
+        *      if (err)
+        *              goto out;
+        */
+       
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
+       err = permission(hidden_inode, mask, nd);
+#else
+       err = permission(hidden_inode, mask);
+#endif
+       
+       /*  out: */
+       return err;
+}
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
+STATIC int
+mini_fo_inode_revalidate(dentry_t *dentry)
+{
+       int err = 0;
+       dentry_t *hidden_dentry;
+       inode_t *hidden_inode;
+
+       ASSERT(dentry->d_inode);
+       ASSERT(itopd(dentry->d_inode));
+
+       if(itohi2(dentry->d_inode)) {
+                hidden_dentry = dtohd2(dentry);
+               hidden_inode = hidden_dentry->d_inode;
+       } else if(itohi(dentry->d_inode)) {
+                hidden_dentry = dtohd(dentry);
+               hidden_inode = hidden_dentry->d_inode;
+       } else {
+                printk(KERN_CRIT "mini_fo_inode_revalidate: ERROR, invalid state detected.\n");
+                err = -ENOENT;
+                goto out;
+        }
+       if (hidden_inode && hidden_inode->i_op && hidden_inode->i_op->revalidate){
+               err = hidden_inode->i_op->revalidate(hidden_dentry);
+               if (err)
+                       goto out;
+       }
+       fist_copy_attr_all(dentry->d_inode, hidden_inode);
+ out:
+       return err;
+}
+#endif
+
+STATIC int
+mini_fo_setattr(dentry_t *dentry, struct iattr *ia)
+{
+       int err = 0;
+
+       check_mini_fo_dentry(dentry);
+       
+       if(!is_mini_fo_existant(dentry)) {
+               printk(KERN_CRIT "mini_fo_setattr: ERROR, invalid state detected [1].\n");
+               goto out;
+       }
+
+       if(dtost(dentry) == UNMODIFIED) {
+               if(!IS_COPY_FLAG(ia->ia_valid))
+                       goto out; /* we ignore these changes to base */
+
+               if(S_ISDIR(dentry->d_inode->i_mode)) {
+                       err = dir_unmod_to_mod(dentry);
+               } else {
+                       /* we copy contents if file is not beeing truncated */
+                       if(S_ISREG(dentry->d_inode->i_mode) && 
+                          !(ia->ia_size == 0 && (ia->ia_valid & ATTR_SIZE))) {
+                               err = nondir_unmod_to_mod(dentry, 1);
+                       } else
+                               err = nondir_unmod_to_mod(dentry, 0);
+               }
+               if(err) {
+                       err = -EINVAL;
+                       printk(KERN_CRIT "mini_fo_setattr: ERROR changing states.\n");
+                       goto out;
+               }
+       }
+       if(!exists_in_storage(dentry)) {
+               printk(KERN_CRIT "mini_fo_setattr: ERROR, invalid state detected [2].\n");
+               err = -EINVAL;
+               goto out;
+       }
+       ASSERT(dentry->d_inode);
+       ASSERT(dtohd2(dentry));
+       ASSERT(itopd(dentry->d_inode));
+       ASSERT(itohi2(dentry->d_inode));
+       
+       err = notify_change(dtohd2(dentry), ia);
+       fist_copy_attr_all(dentry->d_inode, itohi2(dentry->d_inode));
+ out:
+       return err;
+}
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
+STATIC int
+mini_fo_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
+{
+       int err = 0;
+        dentry_t *hidden_dentry;
+
+       ASSERT(dentry->d_inode);
+       ASSERT(itopd(dentry->d_inode));
+
+       if(itohi2(dentry->d_inode)) {
+                hidden_dentry = dtohd2(dentry);
+       } else if(itohi(dentry->d_inode)) {
+                hidden_dentry = dtohd(dentry);
+       } else {
+                printk(KERN_CRIT "mini_fo_getattr: ERROR, invalid state detected.\n");
+                err = -ENOENT;
+                goto out;
+        }
+       fist_copy_attr_all(dentry->d_inode, hidden_dentry->d_inode);
+
+       ASSERT(hidden_dentry);
+       ASSERT(hidden_dentry->d_inode);
+       ASSERT(hidden_dentry->d_inode->i_op);
+
+       generic_fillattr(dentry->d_inode, stat);
+       if (!stat->blksize) {
+               struct super_block *s = hidden_dentry->d_inode->i_sb;
+               unsigned blocks;
+               blocks = (stat->size+s->s_blocksize-1) >> s->s_blocksize_bits;
+               stat->blocks = (s->s_blocksize / 512) * blocks;
+               stat->blksize = s->s_blocksize;
+       }
+ out:
+        return err;
+}
+#endif
+
+#if defined(XATTR) && (LINUX_VERSION_CODE >= KERNEL_VERSION(2,4,20))
+#if 0 /* no xattr_alloc() and xattr_free() */
+/* This is lifted from fs/xattr.c */
+static void *
+xattr_alloc(size_t size, size_t limit)
+{
+       void *ptr;
+
+       if (size > limit)
+               return ERR_PTR(-E2BIG);
+
+       if (!size)      /* size request, no buffer is needed */
+               return NULL;
+       else if (size <= PAGE_SIZE)
+               ptr = kmalloc((unsigned long) size, GFP_KERNEL);
+       else
+               ptr = vmalloc((unsigned long) size);
+       if (!ptr)
+               return ERR_PTR(-ENOMEM);
+       return ptr;
+}
+
+static void
+xattr_free(void *ptr, size_t size)
+{
+       if (!size)      /* size request, no buffer was needed */
+               return;
+       else if (size <= PAGE_SIZE)
+               kfree(ptr);
+       else
+               vfree(ptr);
+}
+#endif /* no xattr_alloc() and xattr_free() */
+
+/* BKL held by caller.
+ * dentry->d_inode->i_sem down
+ */
+STATIC int
+mini_fo_getxattr(struct dentry *dentry, const char *name, void *value, size_t size) {
+       struct dentry *hidden_dentry = NULL;
+       int err = -EOPNOTSUPP;
+       /* Define these anyway so we don't need as much ifdef'ed code. */
+       char *encoded_name = NULL;
+       char *encoded_value = NULL;
+
+       check_mini_fo_dentry(dentry);
+
+       if(exists_in_storage(dentry))
+               hidden_dentry = dtohd2(dentry);
+       else
+               hidden_dentry = dtohd(dentry);
+          
+       ASSERT(hidden_dentry);
+       ASSERT(hidden_dentry->d_inode);
+       ASSERT(hidden_dentry->d_inode->i_op);
+
+       if (hidden_dentry->d_inode->i_op->getxattr) {
+               encoded_name = (char *)name;
+               encoded_value = (char *)value;
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
+               mutex_lock(&hidden_dentry->d_inode->i_mutex);
+#else
+               down(&hidden_dentry->d_inode->i_sem);
+#endif
+               /* lock_kernel() already done by caller. */
+               err = hidden_dentry->d_inode->i_op->getxattr(hidden_dentry, encoded_name, encoded_value, size);
+               /* unlock_kernel() will be done by caller. */
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
+               mutex_lock(&hidden_dentry->d_inode->i_mutex);
+#else
+               up(&hidden_dentry->d_inode->i_sem);
+#endif
+       }
+       return err;
+}
+
+/* BKL held by caller.
+ * dentry->d_inode->i_sem down
+ */
+STATIC int
+#if ((LINUX_VERSION_CODE >= KERNEL_VERSION(2,4,21) \
+     && LINUX_VERSION_CODE <= KERNEL_VERSION(2,4,23)) \
+     || LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0))
+mini_fo_setxattr(struct dentry *dentry, const char *name, 
+                const void *value, size_t size, int flags)
+#else
+mini_fo_setxattr(struct dentry *dentry, const char *name, 
+                void *value, size_t size, int flags)
+#endif
+
+{
+       struct dentry *hidden_dentry = NULL;
+       int err = -EOPNOTSUPP;
+
+       /* Define these anyway, so we don't have as much ifdef'ed code. */
+       char *encoded_value = NULL;
+       char *encoded_name = NULL;
+
+       check_mini_fo_dentry(dentry);
+
+       if(exists_in_storage(dentry))
+               hidden_dentry = dtohd2(dentry);
+       else
+               hidden_dentry = dtohd(dentry);
+       
+       ASSERT(hidden_dentry);
+       ASSERT(hidden_dentry->d_inode);
+       ASSERT(hidden_dentry->d_inode->i_op);
+
+       if (hidden_dentry->d_inode->i_op->setxattr) {
+               encoded_name = (char *)name;
+               encoded_value = (char *)value;
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
+               mutex_lock(&hidden_dentry->d_inode->i_mutex);
+#else
+               down(&hidden_dentry->d_inode->i_sem);
+#endif
+               /* lock_kernel() already done by caller. */
+               err = hidden_dentry->d_inode->i_op->setxattr(hidden_dentry, encoded_name, encoded_value, size, flags);
+               /* unlock_kernel() will be done by caller. */
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
+               mutex_unlock(&hidden_dentry->d_inode->i_mutex);
+#else
+               up(&hidden_dentry->d_inode->i_sem);
+#endif
+       }
+       return err;
+}
+
+/* BKL held by caller.
+ * dentry->d_inode->i_sem down
+ */
+STATIC int
+mini_fo_removexattr(struct dentry *dentry, const char *name) {
+       struct dentry *hidden_dentry = NULL;
+       int err = -EOPNOTSUPP;
+       char *encoded_name;
+
+       check_mini_fo_dentry(dentry);
+
+       if(exists_in_storage(dentry))
+               hidden_dentry = dtohd2(dentry);
+       else
+               hidden_dentry = dtohd(dentry);
+       
+       ASSERT(hidden_dentry);
+       ASSERT(hidden_dentry->d_inode);
+       ASSERT(hidden_dentry->d_inode->i_op);
+
+       if (hidden_dentry->d_inode->i_op->removexattr) {
+               encoded_name = (char *)name;
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
+               mutex_lock(&hidden_dentry->d_inode->i_mutex);
+#else
+               down(&hidden_dentry->d_inode->i_sem);
+#endif
+               /* lock_kernel() already done by caller. */
+               err = hidden_dentry->d_inode->i_op->removexattr(hidden_dentry, encoded_name);
+               /* unlock_kernel() will be done by caller. */
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
+               mutex_unlock(&hidden_dentry->d_inode->i_mutex);
+#else
+               up(&hidden_dentry->d_inode->i_sem);
+#endif
+       }
+       return err;
+}
+
+/* BKL held by caller.
+ * dentry->d_inode->i_sem down
+ */
+STATIC int
+mini_fo_listxattr(struct dentry *dentry, char *list, size_t size) {
+       struct dentry *hidden_dentry = NULL;
+       int err = -EOPNOTSUPP;
+       char *encoded_list = NULL;
+
+       check_mini_fo_dentry(dentry);
+
+       if(exists_in_storage(dentry))
+               hidden_dentry = dtohd2(dentry);
+       else
+               hidden_dentry = dtohd(dentry);
+
+       ASSERT(hidden_dentry);
+       ASSERT(hidden_dentry->d_inode);
+       ASSERT(hidden_dentry->d_inode->i_op);
+
+       if (hidden_dentry->d_inode->i_op->listxattr) {
+               encoded_list = list;
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
+               mutex_lock(&hidden_dentry->d_inode->i_mutex);
+#else
+               down(&hidden_dentry->d_inode->i_sem);
+#endif
+               /* lock_kernel() already done by caller. */
+               err = hidden_dentry->d_inode->i_op->listxattr(hidden_dentry, encoded_list, size);
+               /* unlock_kernel() will be done by caller. */
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
+               mutex_unlock(&hidden_dentry->d_inode->i_mutex);
+#else
+               up(&hidden_dentry->d_inode->i_sem);
+#endif
+       }
+       return err;
+}
+# endif /* defined(XATTR) && (LINUX_VERSION_CODE >= KERNEL_VERSION(2,4,20)) */
+
+struct inode_operations mini_fo_symlink_iops =
+       {
+               readlink:       mini_fo_readlink,
+               follow_link: mini_fo_follow_link,
+               /* mk: permission:      mini_fo_permission, */
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
+               revalidate:     mini_fo_inode_revalidate,
+#endif
+               setattr:        mini_fo_setattr,
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
+               getattr:        mini_fo_getattr,
+               put_link:       mini_fo_put_link,
+#endif
+
+#if defined(XATTR) && (LINUX_VERSION_CODE >= KERNEL_VERSION(2,4,20))
+               setxattr:       mini_fo_setxattr,
+               getxattr:       mini_fo_getxattr,
+               listxattr:      mini_fo_listxattr,
+               removexattr: mini_fo_removexattr
+# endif /* defined(XATTR) && (LINUX_VERSION_CODE >= KERNEL_VERSION(2,4,20)) */
+       };
+