namei.c

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//
// a portion of this function, particularly the VFS interface portion,
// was derived from minix or ext2's analog and evolved as the
// prototype did. You should be able to tell which portion by looking
// at the ext2 code and comparing. It's subfunctions contain no code
// used as a template unless they are so labeled.
//
static int reiserfs_symlink (struct inode * dir, struct dentry * dentry, const char * symname)
{
    int retval;
    struct inode * inode;
    char * name;
    int item_len;
    int windex ;
    struct reiserfs_transaction_handle th ;
    int jbegin_count = JOURNAL_PER_BALANCE_CNT * 3; 


    inode = new_inode(dir->i_sb) ;
    if (!inode) {
	return -ENOMEM ;
    }

    item_len = ROUND_UP (strlen (symname));
    if (item_len > MAX_DIRECT_ITEM_LEN (dir->i_sb->s_blocksize)) {
	iput(inode) ;
	return -ENAMETOOLONG;
    }
  
    name = kmalloc (item_len, GFP_NOFS);
    if (!name) {
	iput(inode) ;
	return -ENOMEM;
    }
    memcpy (name, symname, strlen (symname));
    padd_item (name, item_len, strlen (symname));

    journal_begin(&th, dir->i_sb, jbegin_count) ;
    windex = push_journal_writer("reiserfs_symlink") ;

    inode = reiserfs_new_inode (&th, dir, S_IFLNK | S_IRWXUGO, name, strlen (symname), dentry,
				inode, &retval);
    kfree (name);
    if (inode == 0) { /* reiserfs_new_inode iputs for us */
	pop_journal_writer(windex) ;
	journal_end(&th, dir->i_sb, jbegin_count) ;
	return retval;
    }

    reiserfs_update_inode_transaction(inode) ;
    reiserfs_update_inode_transaction(dir) ;

    inode->i_op = &page_symlink_inode_operations;
    inode->i_mapping->a_ops = &reiserfs_address_space_operations;

    // must be sure this inode is written with this transaction
    //
    //reiserfs_update_sd (&th, inode, READ_BLOCKS);

    retval = reiserfs_add_entry (&th, dir, dentry->d_name.name, dentry->d_name.len, 
				 inode, 1/*visible*/);
    if (retval) {
	inode->i_nlink--;
	reiserfs_update_sd (&th, inode);
	pop_journal_writer(windex) ;
	journal_end(&th, dir->i_sb, jbegin_count) ;
	iput (inode);
	return retval;
    }

    d_instantiate(dentry, inode);
    pop_journal_writer(windex) ;
    journal_end(&th, dir->i_sb, jbegin_count) ;
    return 0;
}


//
// a portion of this function, particularly the VFS interface portion,
// was derived from minix or ext2's analog and evolved as the
// prototype did. You should be able to tell which portion by looking
// at the ext2 code and comparing. It's subfunctions contain no code
// used as a template unless they are so labeled.
//
static int reiserfs_link (struct dentry * old_dentry, struct inode * dir, struct dentry * dentry)
{
    int retval;
    struct inode *inode = old_dentry->d_inode;
    int windex ;
    struct reiserfs_transaction_handle th ;
    int jbegin_count = JOURNAL_PER_BALANCE_CNT * 3; 


    if (S_ISDIR(inode->i_mode))
	return -EPERM;
  
    if (inode->i_nlink >= REISERFS_LINK_MAX) {
	//FIXME: sd_nlink is 32 bit for new files
	return -EMLINK;
    }

    journal_begin(&th, dir->i_sb, jbegin_count) ;
    windex = push_journal_writer("reiserfs_link") ;

    /* create new entry */
    retval = reiserfs_add_entry (&th, dir, dentry->d_name.name, dentry->d_name.len,
				 inode, 1/*visible*/);

    reiserfs_update_inode_transaction(inode) ;
    reiserfs_update_inode_transaction(dir) ;

    if (retval) {
	pop_journal_writer(windex) ;
	journal_end(&th, dir->i_sb, jbegin_count) ;
	return retval;
    }

    inode->i_nlink++;
    inode->i_ctime = CURRENT_TIME;
    reiserfs_update_sd (&th, inode);

    atomic_inc(&inode->i_count) ;
    d_instantiate(dentry, inode);
    pop_journal_writer(windex) ;
    journal_end(&th, dir->i_sb, jbegin_count) ;
    return 0;
}


// de contains information pointing to an entry which 
static int de_still_valid (const char * name, int len, struct reiserfs_dir_entry * de)
{
    struct reiserfs_dir_entry tmp = *de;
    
    // recalculate pointer to name and name length
    set_de_name_and_namelen (&tmp);
    // FIXME: could check more
    if (tmp.de_namelen != len || memcmp (name, de->de_name, len))
	return 0;
    return 1;
}


static int entry_points_to_object (const char * name, int len, struct reiserfs_dir_entry * de, struct inode * inode)
{
    if (!de_still_valid (name, len, de))
	return 0;

    if (inode) {
	if (!de_visible (de->de_deh + de->de_entry_num))
	    reiserfs_panic (0, "vs-7042: entry_points_to_object: entry must be visible");
	return (de->de_objectid == inode->i_ino) ? 1 : 0;
    }

    /* this must be added hidden entry */
    if (de_visible (de->de_deh + de->de_entry_num))
	reiserfs_panic (0, "vs-7043: entry_points_to_object: entry must be visible");

    return 1;
}


/* sets key of objectid the entry has to point to */
static void set_ino_in_dir_entry (struct reiserfs_dir_entry * de, struct key * key)
{
    /* JDM These operations are endian safe - both are le */
    de->de_deh[de->de_entry_num].deh_dir_id = key->k_dir_id;
    de->de_deh[de->de_entry_num].deh_objectid = key->k_objectid;
}


//
// a portion of this function, particularly the VFS interface portion,
// was derived from minix or ext2's analog and evolved as the
// prototype did. You should be able to tell which portion by looking
// at the ext2 code and comparing. It's subfunctions contain no code
// used as a template unless they are so labeled.
//

/* 
 * process, that is going to call fix_nodes/do_balance must hold only
 * one path. If it holds 2 or more, it can get into endless waiting in
 * get_empty_nodes or its clones 
 */
static int reiserfs_rename (struct inode * old_dir, struct dentry *old_dentry,
			    struct inode * new_dir, struct dentry *new_dentry)
{
    int retval;
    INITIALIZE_PATH (old_entry_path);
    INITIALIZE_PATH (new_entry_path);
    INITIALIZE_PATH (dot_dot_entry_path);
    struct item_head new_entry_ih, old_entry_ih, dot_dot_ih ;
    struct reiserfs_dir_entry old_de, new_de, dot_dot_de;
    struct inode * old_inode, * new_inode;
    int windex ;
    struct reiserfs_transaction_handle th ;
    int jbegin_count ; 


    /* two balancings: old name removal, new name insertion or "save" link,
       stat data updates: old directory and new directory and maybe block
       containing ".." of renamed directory */
    jbegin_count = JOURNAL_PER_BALANCE_CNT * 3 + 3;

    old_inode = old_dentry->d_inode;
    new_inode = new_dentry->d_inode;

    // make sure, that oldname still exists and points to an object we
    // are going to rename
    old_de.de_gen_number_bit_string = 0;
    retval = reiserfs_find_entry (old_dir, old_dentry->d_name.name, old_dentry->d_name.len,
				  &old_entry_path, &old_de);
    pathrelse (&old_entry_path);
    if (retval != NAME_FOUND || old_de.de_objectid != old_inode->i_ino) {
	// FIXME: IO error is possible here
	return -ENOENT;
    }

    if (S_ISDIR(old_inode->i_mode)) {
	// make sure, that directory being renamed has correct ".." 
	// and that its new parent directory has not too many links
	// already

	if (new_inode) {
	    if (!reiserfs_empty_dir(new_inode)) {
		return -ENOTEMPTY;
	    }
	}
	
	/* directory is renamed, its parent directory will be changed, 
	** so find ".." entry 
	*/
	dot_dot_de.de_gen_number_bit_string = 0;
	retval = reiserfs_find_entry (old_inode, "..", 2, &dot_dot_entry_path, &dot_dot_de);
	pathrelse (&dot_dot_entry_path);
	if (retval != NAME_FOUND)
	    return -EIO;

	/* inode number of .. must equal old_dir->i_ino */
	if (dot_dot_de.de_objectid != old_dir->i_ino)
	    return -EIO;
    }

    journal_begin(&th, old_dir->i_sb, jbegin_count) ;
    windex = push_journal_writer("reiserfs_rename") ;

    /* add new entry (or find the existing one) */
    retval = reiserfs_add_entry (&th, new_dir, new_dentry->d_name.name, new_dentry->d_name.len, 
				 old_inode, 0);
    if (retval == -EEXIST) {
	// FIXME: is it possible, that new_inode == 0 here? If yes, it
	// is not clear how does ext2 handle that
	if (!new_inode) {
	    reiserfs_panic (old_dir->i_sb,
			    "vs-7050: new entry is found, new inode == 0\n");
	}
    } else if (retval) {
	pop_journal_writer(windex) ;
	journal_end(&th, old_dir->i_sb, jbegin_count) ;
	return retval;
    }

    reiserfs_update_inode_transaction(old_dir) ;
    reiserfs_update_inode_transaction(new_dir) ;

    /* this makes it so an fsync on an open fd for the old name will
    ** commit the rename operation
    */
    reiserfs_update_inode_transaction(old_inode) ;

    if (new_inode) 
	reiserfs_update_inode_transaction(new_inode) ;

    while (1) {
	// look for old name using corresponding entry key (found by reiserfs_find_entry)
	if (search_by_entry_key (new_dir->i_sb, &old_de.de_entry_key, &old_entry_path, &old_de) != NAME_FOUND)
	    BUG ();

	copy_item_head(&old_entry_ih, get_ih(&old_entry_path)) ;

	reiserfs_prepare_for_journal(old_inode->i_sb, old_de.de_bh, 1) ;

	// look for new name by reiserfs_find_entry
	new_de.de_gen_number_bit_string = 0;
	retval = reiserfs_find_entry (new_dir, new_dentry->d_name.name, new_dentry->d_name.len, 
				      &new_entry_path, &new_de);
	if (retval != NAME_FOUND_INVISIBLE && retval != NAME_FOUND)
	    BUG ();

	copy_item_head(&new_entry_ih, get_ih(&new_entry_path)) ;

	reiserfs_prepare_for_journal(old_inode->i_sb, new_de.de_bh, 1) ;

	if (S_ISDIR(old_inode->i_mode)) {
	    if (search_by_entry_key (new_dir->i_sb, &dot_dot_de.de_entry_key, &dot_dot_entry_path, &dot_dot_de) != NAME_FOUND)
		BUG ();
	    copy_item_head(&dot_dot_ih, get_ih(&dot_dot_entry_path)) ;
	    // node containing ".." gets into transaction
	    reiserfs_prepare_for_journal(old_inode->i_sb, dot_dot_de.de_bh, 1) ;
	}
				/* we should check seals here, not do
                                   this stuff, yes? Then, having
                                   gathered everything into RAM we
                                   should lock the buffers, yes?  -Hans */
				/* probably.  our rename needs to hold more 
				** than one path at once.  The seals would 
				** have to be written to deal with multi-path 
				** issues -chris
				*/
	/* sanity checking before doing the rename - avoid races many
	** of the above checks could have scheduled.  We have to be
	** sure our items haven't been shifted by another process.
	*/
	if (item_moved(&new_entry_ih, &new_entry_path) ||
	    !entry_points_to_object(new_dentry->d_name.name, 
	                            new_dentry->d_name.len,
				    &new_de, new_inode) ||
	    item_moved(&old_entry_ih, &old_entry_path) || 
	    !entry_points_to_object (old_dentry->d_name.name, 
	                             old_dentry->d_name.len,
				     &old_de, old_inode)) {
	    reiserfs_restore_prepared_buffer (old_inode->i_sb, new_de.de_bh);
	    reiserfs_restore_prepared_buffer (old_inode->i_sb, old_de.de_bh);
	    if (S_ISDIR(old_inode->i_mode))
		reiserfs_restore_prepared_buffer (old_inode->i_sb, dot_dot_de.de_bh);
	    continue;
	}
	if (S_ISDIR(old_inode->i_mode)) {
	    if ( item_moved(&dot_dot_ih, &dot_dot_entry_path) ||
		 !entry_points_to_object ( "..", 2, &dot_dot_de, old_dir) ) {
		reiserfs_restore_prepared_buffer (old_inode->i_sb, old_de.de_bh);
		reiserfs_restore_prepared_buffer (old_inode->i_sb, new_de.de_bh);
		reiserfs_restore_prepared_buffer (old_inode->i_sb, dot_dot_de.de_bh);
		continue;
	    }
	}


	RFALSE( S_ISDIR(old_inode->i_mode) && 
		!reiserfs_buffer_prepared(dot_dot_de.de_bh), "" );

	break;
    }

    /* ok, all the changes can be done in one fell swoop when we
       have claimed all the buffers needed.*/
    
    mark_de_visible (new_de.de_deh + new_de.de_entry_num);
    set_ino_in_dir_entry (&new_de, INODE_PKEY (old_inode));
    journal_mark_dirty (&th, old_dir->i_sb, new_de.de_bh);

    mark_de_hidden (old_de.de_deh + old_de.de_entry_num);
    journal_mark_dirty (&th, old_dir->i_sb, old_de.de_bh);
    old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME;
    new_dir->i_ctime = new_dir->i_mtime = CURRENT_TIME;

    if (new_inode) {
	// adjust link number of the victim
	if (S_ISDIR(new_inode->i_mode)) {
	    new_inode->i_nlink  = 0;
	} else {
	    new_inode->i_nlink--;
	}
	new_inode->i_ctime = CURRENT_TIME;
    }

    if (S_ISDIR(old_inode->i_mode)) {
	// adjust ".." of renamed directory 
	set_ino_in_dir_entry (&dot_dot_de, INODE_PKEY (new_dir));
	journal_mark_dirty (&th, new_dir->i_sb, dot_dot_de.de_bh);
	
        if (!new_inode)
	    /* there (in new_dir) was no directory, so it got new link
	       (".."  of renamed directory) */
	    INC_DIR_INODE_NLINK(new_dir);
		
	/* old directory lost one link - ".. " of renamed directory */
	DEC_DIR_INODE_NLINK(old_dir);
    }

    // looks like in 2.3.99pre3 brelse is atomic. so we can use pathrelse
    pathrelse (&new_entry_path);
    pathrelse (&dot_dot_entry_path);

    // FIXME: this reiserfs_cut_from_item's return value may screw up
    // anybody, but it will panic if will not be able to find the
    // entry. This needs one more clean up
    if (reiserfs_cut_from_item (&th, &old_entry_path, &(old_de.de_entry_key), old_dir, NULL, 0) < 0)
	reiserfs_warning ("vs-7060: reiserfs_rename: couldn't not cut old name. Fsck later?\n");

    old_dir->i_size -= DEH_SIZE + old_de.de_entrylen;
    old_dir->i_blocks = ((old_dir->i_size + 511) >> 9);

    reiserfs_update_sd (&th, old_dir);
    reiserfs_update_sd (&th, new_dir);

    if (new_inode) {
	if (new_inode->i_nlink == 0)
	    add_save_link (&th, new_inode, 0/* not truncate */);
	reiserfs_update_sd (&th, new_inode);
    }

    pop_journal_writer(windex) ;
    journal_end(&th, old_dir->i_sb, jbegin_count) ;
    return 0;
}



/*
 * directories can handle most operations...
 */
struct inode_operations reiserfs_dir_inode_operations = {
  //&reiserfs_dir_operations,	/* default_file_ops */
    create:	reiserfs_create,
    lookup:	reiserfs_lookup,
    link:	reiserfs_link,
    unlink:	reiserfs_unlink,
    symlink:	reiserfs_symlink,
    mkdir:	reiserfs_mkdir,
    rmdir:	reiserfs_rmdir,
    mknod:	reiserfs_mknod,
    rename:	reiserfs_rename,
};