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copyup.c

/*
 * Copyright (c) 2003-2006 Erez Zadok
 * Copyright (c) 2003-2006 Charles P. Wright
 * Copyright (c) 2005-2006 Josef 'Jeff' Sipek
 * Copyright (c) 2005-2006 Junjiro Okajima
 * Copyright (c) 2005      Arun M. Krishnakumar
 * Copyright (c) 2005-2006 David P. Quigley
 * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
 * Copyright (c) 2003      Puja Gupta
 * Copyright (c) 2003      Harikesavan Krishnan
 * Copyright (c) 2003-2006 Stony Brook University
 * Copyright (c) 2003-2006 The Research Foundation of State University of New York*
 *
 * For specific licensing information, see the COPYING file distributed with
 * this package.
 *
 * This Copyright notice must be kept intact and distributed with all sources.
 */
/*
 *  $Id: copyup.c,v 1.78 2006/10/31 18:05:33 yiannos Exp $
 */

#include "unionfs.h"

/*Not Working Yet*/
static int copyup_xattrs(struct dentry *old_hidden_dentry,
                   struct dentry *new_hidden_dentry)
{
      int err = 0;
      ssize_t list_size = -1;
      char *name_list = NULL;
      char *attr_value = NULL;
      char *name_list_orig = NULL;

      print_entry_location();

      list_size = vfs_listxattr(old_hidden_dentry, NULL, 0);

      if (list_size <= 0) {
            err = list_size;
            goto out;
      }

      name_list = xattr_alloc(list_size + 1, XATTR_LIST_MAX);
      if (!name_list || IS_ERR(name_list)) {
            err = PTR_ERR(name_list);
            goto out;
      }
      list_size = vfs_listxattr(old_hidden_dentry, name_list, list_size);
      attr_value = xattr_alloc(XATTR_SIZE_MAX, XATTR_SIZE_MAX);
      if (!attr_value || IS_ERR(attr_value)) {
            err = PTR_ERR(name_list);
            goto out;
      }
      name_list_orig = name_list;
      while (*name_list) {
            ssize_t size;

            //We need to lock here since vfs_getxattr doesn't lock for us.
            mutex_lock(&old_hidden_dentry->d_inode->i_mutex);
            size = vfs_getxattr(old_hidden_dentry, name_list,
                            attr_value, XATTR_SIZE_MAX);
            mutex_unlock(&old_hidden_dentry->d_inode->i_mutex);
            if (size < 0) {
                  err = size;
                  goto out;
            }

            if (size > XATTR_SIZE_MAX) {
                  err = -E2BIG;
                  goto out;
            }
            //We don't need to lock here since vfs_setxattr does it for us.
            err = vfs_setxattr(new_hidden_dentry, name_list, attr_value,
                           size, 0);

            if (err < 0)
                  goto out;
            name_list += strlen(name_list) + 1;
      }
      out:
      name_list = name_list_orig;

      if (name_list)
            xattr_free(name_list, list_size + 1);
      if (attr_value)
            xattr_free(attr_value, XATTR_SIZE_MAX);
      /* It is no big deal if this fails, we just roll with the punches. */
      if (err == -ENOTSUPP || err == -EOPNOTSUPP)
            err = 0;
      return err;
}

/* Determine the mode based on the copyup flags, and the existing dentry. */
static int copyup_permissions(struct super_block *sb,
                        struct dentry *old_hidden_dentry,
                        struct dentry *new_hidden_dentry)
{
      struct iattr newattrs;
      int err;

      print_entry_location();

      newattrs.ia_atime = old_hidden_dentry->d_inode->i_atime;
      newattrs.ia_mtime = old_hidden_dentry->d_inode->i_mtime;
      newattrs.ia_ctime = old_hidden_dentry->d_inode->i_ctime;
      newattrs.ia_valid = ATTR_CTIME | ATTR_ATIME | ATTR_MTIME |
          ATTR_ATIME_SET | ATTR_MTIME_SET;
      /* original mode of old file */
      newattrs.ia_mode = old_hidden_dentry->d_inode->i_mode;
      newattrs.ia_gid = old_hidden_dentry->d_inode->i_gid;
      newattrs.ia_uid = old_hidden_dentry->d_inode->i_uid;
      newattrs.ia_valid |= ATTR_FORCE | ATTR_GID | ATTR_UID | ATTR_MODE;
      if (newattrs.ia_valid & ATTR_MODE) {
            newattrs.ia_mode =
                (newattrs.ia_mode & S_IALLUGO) | (old_hidden_dentry->
                                          d_inode->
                                          i_mode & ~S_IALLUGO);
      }

      err = notify_change(new_hidden_dentry, &newattrs);

      print_exit_status(err);
      return err;
}

int copyup_dentry(struct inode *dir, struct dentry *dentry,
              int bstart, int new_bindex,
              struct file **copyup_file, loff_t len)
{
      return copyup_named_dentry(dir, dentry, bstart, new_bindex,
                           dentry->d_name.name,
                           dentry->d_name.len, copyup_file, len);
}

int copyup_named_dentry(struct inode *dir, struct dentry *dentry,
                  int bstart, int new_bindex, const char *name,
                  int namelen, struct file **copyup_file, loff_t len)
{
      struct dentry *new_hidden_dentry;
      struct dentry *old_hidden_dentry = NULL;
      struct super_block *sb;
      struct file *input_file = NULL;
      struct file *output_file = NULL;
      struct sioq_args args;
      ssize_t read_bytes, write_bytes;
      mm_segment_t old_fs;
      int err = 0;
      char *buf;
      int old_bindex;
      int got_branch_input = -1;
      int got_branch_output = -1;
      int old_bstart;
      int old_bend;
      int old_mode;
      loff_t size = len;
      struct dentry *new_hidden_parent_dentry = NULL;
      mm_segment_t oldfs;
      char *symbuf = NULL;

      print_entry_location();
      verify_locked(dentry);
      print_dentry("IN: copyup_named_dentry", dentry);

      old_bindex = bstart;
      old_bstart = dbstart(dentry);
      old_bend = dbend(dentry);

      BUG_ON(new_bindex < 0);
      BUG_ON(new_bindex >= old_bindex);

      sb = dir->i_sb;

      unionfs_read_lock(sb);

      if ((err = is_robranch_super(sb, new_bindex)))
            goto out;

      /* Create the directory structure above this dentry. */
      new_hidden_dentry = create_parents_named(dir, dentry, name, new_bindex);
      if (IS_ERR(new_hidden_dentry)) {
            err = PTR_ERR(new_hidden_dentry);
            goto out;
      }

      print_dentry("Copyup Object", new_hidden_dentry);

      /* Now we actually create the object. */
      old_hidden_dentry = dtohd_index(dentry, old_bindex);
      DGET(old_hidden_dentry);
      
      old_mode = old_hidden_dentry->d_inode->i_mode;

      /* For symlinks, we must read the link before we lock the directory. */
      if (S_ISLNK(old_mode)) {

            symbuf = KMALLOC(PATH_MAX, GFP_KERNEL);
            if (!symbuf) {
                  err = -ENOMEM;
                  goto copyup_readlink_err;
            }

            oldfs = get_fs();
            set_fs(KERNEL_DS);
            err =
                old_hidden_dentry->d_inode->i_op->
                readlink(old_hidden_dentry, (char __user *)symbuf,
                       PATH_MAX);
            set_fs(oldfs);
            if (err < 0)
                  goto copyup_readlink_err;
            symbuf[err] = '\0';
      }

      /* Now we lock the parent, and create the object in the new branch. */
      new_hidden_parent_dentry = lock_parent(new_hidden_dentry);
      if (S_ISDIR(old_mode)) {
            args.mkdir.parent = new_hidden_parent_dentry->d_inode;
            args.mkdir.dentry = new_hidden_dentry;
            args.mkdir.mode = old_mode; /*S_IRWXU*/
            run_sioq(__unionfs_mkdir, &args);
            err = args.err;
      } else if (S_ISLNK(old_mode)) {
            args.symlink.parent = new_hidden_parent_dentry->d_inode;
            args.symlink.dentry = new_hidden_dentry;
            args.symlink.symbuf = symbuf;
            args.symlink.mode = old_mode;
            run_sioq(__unionfs_symlink, &args);
            err = args.err;
      } else if (S_ISBLK(old_mode)
               || S_ISCHR(old_mode)
               || S_ISFIFO(old_mode)
               || S_ISSOCK(old_mode)) {
            args.mknod.parent = new_hidden_parent_dentry->d_inode;
            args.mknod.dentry = new_hidden_dentry;
            args.mknod.mode = old_mode;
            args.mknod.dev = old_hidden_dentry->d_inode->i_rdev;
            run_sioq(__unionfs_mknod, &args);
            err = args.err;   
      } else if (S_ISREG(old_mode)) {
            args.create.parent = new_hidden_parent_dentry->d_inode;
            args.create.dentry = new_hidden_dentry;
            args.create.mode = old_mode;
            args.create.nd = NULL;
            run_sioq(__unionfs_create, &args);
            err = args.err;
      } else {
            printk(KERN_ERR "Unknown inode type %d\n",
                   old_hidden_dentry->d_inode->i_mode);
            BUG();
      }

      copyup_readlink_err:
      KFREE(symbuf);
      if (err) {
            /* get rid of the hidden dentry and all its traces */
            DPUT(new_hidden_dentry);
            set_dtohd_index(dentry, new_bindex, NULL);
            set_dbstart(dentry, old_bstart);
            set_dbend(dentry, old_bend);
            goto out_dir;
      }
#ifdef UNIONFS_IMAP
      if (stopd(sb)->usi_persistent) {
            err = write_uin(dentry->d_sb, dentry->d_inode->i_ino,
                        new_bindex, new_hidden_dentry->d_inode->i_ino);
            if (err)
                  goto out_dir;
      }
#endif
      /* We actually copyup the file here. */
      if (S_ISREG(old_hidden_dentry->d_inode->i_mode)) {
            mntget(stohiddenmnt_index(sb, old_bindex));
            branchget(sb, old_bindex);
            got_branch_input = old_bindex;
            input_file =
                DENTRY_OPEN(old_hidden_dentry,
                        stohiddenmnt_index(sb, old_bindex),
                        O_RDONLY | O_LARGEFILE);
            if (IS_ERR(input_file)) {
                  err = PTR_ERR(input_file);
                  goto out_dir;
            }
            if (!input_file->f_op || !input_file->f_op->read) {
                  err = -EINVAL;
                  goto out_dir;
            }

            /* copy the new file */
            DGET(new_hidden_dentry);
            mntget(stohiddenmnt_index(sb, new_bindex));
            branchget(sb, new_bindex);
            got_branch_output = new_bindex;
            output_file =
                DENTRY_OPEN(new_hidden_dentry,
                        stohiddenmnt_index(sb, new_bindex),
                        O_WRONLY | O_LARGEFILE);
            if (IS_ERR(output_file)) {
                  err = PTR_ERR(output_file);
                  goto out_dir;
            }
            if (!output_file->f_op || !output_file->f_op->write) {
                  err = -EINVAL;
                  goto out_dir;
            }

            /* allocating a buffer */
            buf = (char *)KMALLOC(PAGE_SIZE, GFP_KERNEL);
            if (!buf) {
                  err = -ENOMEM;
                  goto out_dir;
            }

            /* now read PAGE_SIZE bytes from offset 0 in a loop */
            old_fs = get_fs();

            input_file->f_pos = 0;
            output_file->f_pos = 0;

            err = 0;    // reset error just in case
            set_fs(KERNEL_DS);
            do {
                  if (len >= PAGE_SIZE)
                        size = PAGE_SIZE;
                  else if ((len < PAGE_SIZE) && (len > 0))
                        size = len;

                  len -= PAGE_SIZE;

                  read_bytes =
                      input_file->f_op->read(input_file,
                                       (char __user *)buf, size,
                                       &input_file->f_pos);
                  if (read_bytes <= 0) {
                        err = read_bytes;
                        break;
                  }

                  write_bytes =
                      output_file->f_op->write(output_file,
                                         (char __user *)buf,
                                         read_bytes,
                                         &output_file->f_pos);
                  if (write_bytes < 0 || (write_bytes < read_bytes)) {
                        err = write_bytes;
                        break;
                  }
            } while ((read_bytes > 0) && (len > 0));
            set_fs(old_fs);
            KFREE(buf);
#ifdef UNIONFS_MMAP
            /* SP: Now that we copied up the file, have to sync its data
             * as otherwise when we do a read_cache_page(), we'll possibly
             * read crap.
             *
             * another posisble solution would be in the address op code
             * would be to check the "lower" page to see if its dirty,
             * and if it's dirty, use it directl
             */
            if (!err) {
                  err =
                      output_file->f_op->fsync(output_file,
                                         new_hidden_dentry, 0);
            }
#endif
            if (err) {
                  /* copyup failed, because we ran out of space or quota,
                   * or something else happened so let's unlink; we don't
                   * really care about the return value of vfs_unlink */
                  vfs_unlink(new_hidden_parent_dentry->d_inode,
                           new_hidden_dentry);

                  goto out_dir;
            }
      }

      /* Set permissions. */
      if ((err =
           copyup_permissions(sb, old_hidden_dentry, new_hidden_dentry)))
            goto out_dir;
      /* Selinux uses extended attributes for permissions. */
      if ((err = copyup_xattrs(old_hidden_dentry, new_hidden_dentry)))
            goto out_dir;

      /* do not allow files getting deleted to be reinterposed */
      if (!d_deleted(dentry))
            unionfs_reinterpose(dentry);

      out_dir:
      if (new_hidden_parent_dentry)
            unlock_dir(new_hidden_parent_dentry);

      out:
      if (input_file && !IS_ERR(input_file)) {
            fput(input_file);
      } else {
            /* since input file was not opened, we need to explicitly
             * dput the old_hidden_dentry
             */
            DPUT(old_hidden_dentry);
      }

      /* in any case, we have to branchput */
      if (got_branch_input >= 0)
            branchput(sb, got_branch_input);

      if (output_file) {
            if (copyup_file && !err) {
                  *copyup_file = output_file;
            } else {
                  /* close the file if there was no error, or if we ran
                   * out of space in which case we unlinked the file */
                  if (!IS_ERR(output_file))
                        fput(output_file);
                  branchput(sb, got_branch_output);
            }
      }

      unionfs_read_unlock(sb);

      print_dentry("OUT: copyup_dentry", dentry);
      print_inode("OUT: copyup_dentry", dentry->d_inode);

      print_exit_status(err);
      return err;
}

/* This function creates a copy of a file represented by 'file' which currently
 * resides in branch 'bstart' to branch 'new_bindex.  The copy will be named
 * "name".  */
int copyup_named_file(struct inode *dir, struct file *file, char *name,
                  int bstart, int new_bindex, loff_t len)
{
      int err = 0;
      struct file *output_file = NULL;

      print_entry_location();

      err = copyup_named_dentry(dir, file->f_dentry, bstart,
                          new_bindex, name, strlen(name), &output_file,
                          len);
      if (!err) {
            fbstart(file) = new_bindex;
            set_ftohf_index(file, new_bindex, output_file);
      }

      print_exit_status(err);
      return err;
}

/* This function creates a copy of a file represented by 'file' which currently
 * resides in branch 'bstart' to branch 'new_bindex.
 */
int copyup_file(struct inode *dir, struct file *file, int bstart,
            int new_bindex, loff_t len)
{
      int err = 0;
      struct file *output_file = NULL;

      print_entry_location();

      err = copyup_dentry(dir, file->f_dentry, bstart, new_bindex,
                      &output_file, len);
      if (!err) {
            fbstart(file) = new_bindex;
            set_ftohf_index(file, new_bindex, output_file);
      }

      print_exit_status(err);
      return err;
}

/* This function replicates the directory structure upto given dentry
 * in the bindex branch. Can create directory structure recursively to the right
 * also.
 */
struct dentry *create_parents(struct inode *dir, struct dentry *dentry,
                        int bindex)
{
      struct dentry *hidden_dentry;

      print_entry_location();
      hidden_dentry =
          create_parents_named(dir, dentry, dentry->d_name.name, bindex);
      print_exit_location();

      return (hidden_dentry);
}

/* This function replicates the directory structure upto given dentry
 * in the bindex branch.  */
struct dentry *create_parents_named(struct inode *dir, struct dentry *dentry,
                            const char *name, int bindex)
{
      int err;
      struct dentry *child_dentry;
      struct dentry *parent_dentry;
      struct dentry *hidden_parent_dentry = NULL;
      struct dentry *hidden_dentry = NULL;
      struct sioq_args args;
      const char *childname;
      unsigned int childnamelen;

      int old_kmalloc_size;
      int kmalloc_size;
      int num_dentry;
      int count;

      int old_bstart;
      int old_bend;
      struct dentry **path = NULL;
      struct dentry **tmp_path;
      struct super_block *sb;
#ifdef UNIONFS_IMAP
      int persistent;
#endif
      print_entry_location();

      verify_locked(dentry);

      /* There is no sense allocating any less than the minimum. */
      kmalloc_size = malloc_sizes[0].cs_size;
      num_dentry = kmalloc_size / sizeof(struct dentry *);

      if ((err = is_robranch_super(dir->i_sb, bindex))) {
            hidden_dentry = ERR_PTR(err);
            goto out;
      }

      print_dentry("IN: create_parents_named", dentry);
      dprint(PRINT_DEBUG, "name = %s\n", name);

      old_bstart = dbstart(dentry);
      old_bend = dbend(dentry);

      hidden_dentry = ERR_PTR(-ENOMEM);
      path = (struct dentry **)KZALLOC(kmalloc_size, GFP_KERNEL);
      if (!path)
            goto out;

      /* assume the negative dentry of unionfs as the parent dentry */
      parent_dentry = dentry;

      count = 0;
      /* This loop finds the first parent that exists in the given branch.
       * We start building the directory structure from there.  At the end
       * of the loop, the following should hold:
       *      child_dentry is the first nonexistent child
       *      parent_dentry is the first existent parent
       *      path[0] is the = deepest child
       *      path[count] is the first child to create
       */
      do {
            child_dentry = parent_dentry;

            /* find the parent directory dentry in unionfs */
            parent_dentry = child_dentry->d_parent;
            lock_dentry(parent_dentry);

            /* find out the hidden_parent_dentry in the given branch */
            hidden_parent_dentry = dtohd_index(parent_dentry, bindex);

            /* store the child dentry */
            path[count++] = child_dentry;
            if (count == num_dentry) {
                  old_kmalloc_size = kmalloc_size;
                  kmalloc_size *= 2;
                  num_dentry = kmalloc_size / sizeof(struct dentry *);

                  tmp_path =
                      (struct dentry **)KZALLOC(kmalloc_size, GFP_KERNEL);
                  if (!tmp_path) {
                        hidden_dentry = ERR_PTR(-ENOMEM);
                        goto out;
                  }
                  memcpy(tmp_path, path, old_kmalloc_size);
                  KFREE(path);
                  path = tmp_path;
                  tmp_path = NULL;
            }

      } while (!hidden_parent_dentry);
      count--;

      sb = dentry->d_sb;
#ifdef UNIONFS_IMAP
      persistent = stopd(sb)->usi_persistent;
#endif
      /* This is basically while(child_dentry != dentry).  This loop is
       * horrible to follow and should be replaced with cleaner code. */
      while (1) {
            // get hidden parent dir in the current branch
            hidden_parent_dentry = dtohd_index(parent_dentry, bindex);
            unlock_dentry(parent_dentry);

            // init the values to lookup
            childname = child_dentry->d_name.name;
            childnamelen = child_dentry->d_name.len;

            if (child_dentry != dentry) {
                  // lookup child in the underlying file system
                  hidden_dentry =
                      LOOKUP_ONE_LEN(childname, hidden_parent_dentry,
                                 childnamelen);
                  if (IS_ERR(hidden_dentry))
                        goto out;
            } else {
                  int loop_start;
                  int loop_end;
                  int new_bstart = -1;
                  int new_bend = -1;
                  int i;

                  /* is the name a whiteout of the childname ? */
                  //lookup the whiteout child in the underlying file system
                  hidden_dentry =
                      LOOKUP_ONE_LEN(name, hidden_parent_dentry,
                                 strlen(name));
                  if (IS_ERR(hidden_dentry))
                        goto out;

                  /* Replace the current dentry (if any) with the new one. */
                  DPUT(dtohd_index(dentry, bindex));
                  set_dtohd_index(dentry, bindex, hidden_dentry);

                  loop_start =
                      (old_bstart < bindex) ? old_bstart : bindex;
                  loop_end = (old_bend > bindex) ? old_bend : bindex;

                  /* This loop sets the bstart and bend for the new
                   * dentry by traversing from left to right.
                   * It also dputs all negative dentries except
                   * bindex (the newly looked dentry
                   */
                  for (i = loop_start; i <= loop_end; i++) {
                        if (!dtohd_index(dentry, i))
                              continue;

                        if (i == bindex) {
                              new_bend = i;
                              if (new_bstart < 0)
                                    new_bstart = i;
                              continue;
                        }

                        if (!dtohd_index(dentry, i)->d_inode) {
                              DPUT(dtohd_index(dentry, i));
                              set_dtohd_index(dentry, i, NULL);
                        } else {
                              if (new_bstart < 0)
                                    new_bstart = i;
                              new_bend = i;
                        }
                  }

                  if (new_bstart < 0)
                        new_bstart = bindex;
                  if (new_bend < 0)
                        new_bend = bindex;
                  set_dbstart(dentry, new_bstart);
                  set_dbend(dentry, new_bend);
                  break;
            }

            if (hidden_dentry->d_inode) {
                  /* since this already exists we dput to avoid
                   * multiple references on the same dentry */
                  DPUT(hidden_dentry);
            } else {

                  /* its a negative dentry, create a new dir */
                  hidden_parent_dentry = lock_parent(hidden_dentry);
                  args.mkdir.parent = hidden_parent_dentry->d_inode;
                  args.mkdir.dentry = hidden_dentry;
                  args.mkdir.mode = child_dentry->d_inode->i_mode;
                  run_sioq(__unionfs_mkdir, &args);
                  err = args.err;
                  if (!err)
                        err = copyup_permissions
                            (dir->i_sb, child_dentry, hidden_dentry);
                  unlock_dir(hidden_parent_dentry);
                  if (err) {
                        DPUT(hidden_dentry);
                        hidden_dentry = ERR_PTR(err);
                        goto out;
                  }
#ifdef UNIONFS_IMAP
                  if (persistent) {
                        err = write_uin
                            (sb, child_dentry->d_inode->i_ino,
                             bindex, hidden_dentry->d_inode->i_ino);
                        if (err) {
                              DPUT(hidden_dentry);
                              hidden_dentry = ERR_PTR(err);
                              goto out;
                        }
                  }
#endif
                  set_itohi_index(child_dentry->d_inode, bindex,
                              IGRAB(hidden_dentry->d_inode));
                  if (ibstart(child_dentry->d_inode) > bindex)
                        ibstart(child_dentry->d_inode) = bindex;
                  if (ibend(child_dentry->d_inode) < bindex)
                        ibend(child_dentry->d_inode) = bindex;

                  set_dtohd_index(child_dentry, bindex, hidden_dentry);
                  if (dbstart(child_dentry) > bindex)
                        set_dbstart(child_dentry, bindex);
                  if (dbend(child_dentry) < bindex)
                        set_dbend(child_dentry, bindex);
            }

            parent_dentry = child_dentry;
            child_dentry = path[--count];
      }
      out:
      KFREE(path);
      print_dentry("OUT: create_parents_named", dentry);
      print_exit_pointer(hidden_dentry);
      return hidden_dentry;
}

/*
 *
 * vim:shiftwidth=8
 * vim:tabstop=8
 *
 * For Emacs:
 * Local variables:
 * c-basic-offset: 8
 * c-comment-only-line-offset: 0
 * c-offsets-alist: ((statement-block-intro . +) (knr-argdecl-intro . 0)
 *              (substatement-open . 0) (label . 0) (statement-cont . +))
 * indent-tabs-mode: t
 * tab-width: 8
 * End:
 */

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