dir40.c

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	{
	
		/* Removing body item. */	
		if (obj40_update_body(dir, dir40_entry_comp) == PRESENT) {
			body_hint.count = 1;
			body_hint.place_func = NULL;
			body_hint.region_func = NULL;
			dir->body.pos.unit = MAX_UINT32;
			
			obj40_remove(dir, &dir->body, &body_hint);
		}
		
		return res;
	}
	
	return 0;
}

/* Removes all directory body items. */
static errno_t dir40_mkempty(reiser4_object_t *dir, uint64_t n) {
	errno_t res;
	reiser4_key_t key;

	aal_assert("umka-1925", dir != NULL);

	/* Making sure, that dir->body points to correct item */
	if ((res = obj40_update_body(dir, dir40_entry_comp)) != PRESENT)
		return res  == ABSENT ? 0 : res;

	/* Creating maximal possible key in order to find last directory item
	   and remove it from the tree. Thanks to Nikita for this idea. */
	aal_memcpy(&key, &dir->body.key, sizeof(key));
	objcall(&key, set_offset, MAX_UINT64);

	while (1) {
		trans_hint_t hint;

		/* Looking for the last directory item. 
		   FIXME: the possible speedup here is to get rid of 
		   lookup */
		if ((res = obj40_find_item(dir, &key, FIND_EXACT, NULL, 
					   NULL, &dir->body)) < 0)
		{
			return res;
		}

		/* Checking if found item belongs this directory */
		if (obj40_belong(&dir->body, &key) == ABSENT)
			return 0;

		aal_memset(&hint, 0, sizeof(hint));
		
		hint.count = 1;
		hint.shift_flags = SF_DEFAULT;
		dir->body.pos.unit = MAX_UINT32;
		
		/* Removing item from the tree */
		if ((res = obj40_remove(dir, &dir->body, &hint)))
			return res;
	}
	
	return 0;
}

/* Removes directory body and stat data from the tree. */
static errno_t dir40_clobber(reiser4_object_t *dir) {
	uint32_t nlink;
	errno_t res;
		
	aal_assert("umka-2298", dir != NULL);
	
	/* Check that truncate is allowed -- i.e. nlink == 2. */
	if ((nlink = obj40_get_nlink(dir, 1)) != 2) {
		aal_error("Can't detach the object "
			  "with nlink (%d).", nlink);
		return -EINVAL;
	}

	dir40_reset(dir);
	
	/* Truncates directory body. */
	if ((res = dir40_mkempty(dir, 0)))
		return res;

	/* Cloberring stat data. */
	return obj40_clobber(dir);
}

/* Return number of hard links. */
static bool_t dir40_linked(reiser4_object_t *dir) {
	return obj40_get_nlink(dir, 1) != 1;
}

/* Helper function. Builds @entry->offset key by @entry->name. */
static errno_t dir40_build_entry(reiser4_object_t *dir, 
				 entry_hint_t *entry)
{
	aal_assert("umka-2528", entry != NULL);
	aal_assert("umka-2527", dir != NULL);
	
	plugcall(dir->info.object.plug, build_hashed, &entry->offset, 
		 reiser4_pshash(dir), reiser4_psfibre(dir),
		 objcall(&dir->info.object, get_locality),
		 objcall(&dir->info.object, get_objectid), entry->name);

	return 0;
}

/* Add new entry to directory. */
static errno_t dir40_add_entry(reiser4_object_t *dir, 
			       entry_hint_t *entry)
{
	errno_t res;
	
	entry_hint_t temp;
	trans_hint_t hint;

	aal_assert("umka-844", dir != NULL);
	aal_assert("umka-845", entry != NULL);

	aal_memset(&hint, 0, sizeof(hint));
	
	/* Getting place new entry will be inserted at. */
	switch (dir40_search(dir, entry->name,
			     FIND_EXACT, &temp))
	{
	case ABSENT:
		if (!obj40_valid_item(&temp.place))
			return -EINVAL;
		
		if ((res = obj40_fetch_item(&temp.place)))
			return res;
		
		break;
	case PRESENT:
		aal_error("Entry \"%s\" already exists.",
			  entry->name);
	default:
		return -EINVAL;
	}

	/* Prepare trans hint. */
	hint.count = 1;
	hint.region_func = NULL;
	hint.place_func = entry->place_func;
	hint.data = entry->data;
	
	hint.plug = temp.place.plug;
	hint.specific = (void *)entry;
	hint.shift_flags = SF_DEFAULT;

	/* Building key of the new entry and hint's one */
	dir40_build_entry(dir, entry);

	/* Copying key to @hint */
	aal_memcpy(&hint.offset, &entry->offset, sizeof(hint.offset));

	/* Inserting entry described by @hint to tree at @temp.place */
	if ((res = obj40_insert(dir, &temp.place,
				&hint, LEAF_LEVEL)) < 0)
	{
		return res;
	}

	entry->len = hint.len;
	
	/* Updating stat data fields. */
	return obj40_touch(dir, 1, hint.bytes);
}

/* Removing entry from the directory */
static errno_t dir40_rem_entry(reiser4_object_t *dir,
			       entry_hint_t *entry)
{
	errno_t res;
	entry_hint_t temp;
	trans_hint_t hint;
	
	aal_assert("umka-1923", entry != NULL);
	aal_assert("umka-1922", dir != NULL);
	aal_assert("umka-2390", entry->name != NULL);

	/* Looking for place to insert directory entry */
	if (dir40_search(dir, entry->name, FIND_EXACT, &temp) != PRESENT)
		return -EINVAL;
	
	aal_memset(&hint, 0, sizeof(hint));
	
	hint.count = 1;
	hint.shift_flags = SF_DEFAULT;
	
	/* Removing one unit from directory */
	if ((res = obj40_remove(dir, &dir->body, &hint)))
		return res;
	
	if (!objcall(&dir->position, compfull, &temp.offset)) {
		if (entry->offset.adjust < dir->position.adjust)
			dir->position.adjust--;
	}

	entry->len = hint.len;
	
	/* Updating stat data fields */
	return obj40_touch(dir, -1, -hint.bytes);
}

/* Attaches the given directory @dir to @parent object. */
static errno_t dir40_attach(reiser4_object_t *dir,
			    reiser4_object_t *parent)
{
	errno_t res;
	entry_hint_t entry;
	
	aal_assert("umka-2289", dir != NULL);
	aal_assert("umka-2359", parent != NULL);

	aal_memset(&entry, 0, sizeof(entry));
	
	aal_strncpy(entry.name, "..", sizeof(entry.name));

	/* Adding ".." pointing to parent to @dir object. */
	aal_memcpy(&entry.object, &parent->info.object, sizeof(entry.object));

	if ((res = dir40_add_entry(dir, &entry)))
		return res;

	/* Increasing parent's @nlink by one */
	return plugcall(reiser4_psobj(parent), link, parent);
}

/* Detaches @dir from @parent. */
static errno_t dir40_detach(reiser4_object_t *dir,
			    reiser4_object_t *parent)
{
	entry_hint_t entry;
	errno_t res;

	aal_assert("umka-2291", dir != NULL);

	/* Removing ".." from child if it is found */
	if (dir40_lookup(dir, "..", &entry) == PRESENT) {
		if ((res = dir40_rem_entry(dir, &entry)))
			return res;
	}
	
	if (!parent) 
		return 0;
	
	/* Decreasing parent's @nlink by one */
	return plugcall(reiser4_psobj(parent), unlink, parent);
}

/* This fucntion implements hashed directory enumerator function. It is used for
   calculating fargmentation, prining. */
static errno_t dir40_layout(reiser4_object_t *dir,
			    region_func_t func,
			    void *data)
{
	dir40_reset(dir);
	return obj40_layout(dir, func, dir40_entry_comp, data);
}

/* This fucntion implements hashed directory metadata enumerator function. This
   is needed for getting directory metadata for pack them, etc. */
static errno_t dir40_metadata(reiser4_object_t *dir,
			      place_func_t place_func,
			      void *data)
{
	dir40_reset(dir);
	return obj40_traverse(dir, place_func, dir40_entry_comp, data);
}
#endif

/* Directory object operations. */
reiser4_object_plug_t dir40_plug = {
	.p = {
		.id    = {OBJECT_DIR40_ID, DIR_OBJECT, OBJECT_PLUG_TYPE},
#ifndef ENABLE_MINIMAL
		.label = "dir40",
		.desc  = "Directory file plugin.",
#endif
	},

#ifndef ENABLE_MINIMAL
	.inherit	= obj40_inherit,
	.create		= dir40_create,
	.layout		= dir40_layout,
	.metadata	= dir40_metadata,
	.link		= obj40_link,
	.unlink		= obj40_unlink,
	.linked		= dir40_linked,
	.truncate	= NULL,
	.add_entry	= dir40_add_entry,
	.rem_entry	= dir40_rem_entry,
	.build_entry    = dir40_build_entry,
	.attach		= dir40_attach,
	.detach		= dir40_detach,
	.clobber	= dir40_clobber,
	.recognize	= obj40_recognize,
	.fake		= dir40_fake,
	.check_struct	= dir40_check_struct,
	.check_attach	= dir40_check_attach,

	.seek		= NULL,
	.write		= NULL,
	.convert        = NULL,
#endif
	.follow		= NULL,
	.read		= NULL,
	.offset		= NULL,
	
	.stat           = obj40_load_stat,
	.open		= obj40_open,
	.close		= NULL,
	.reset		= dir40_reset,
	.lookup		= dir40_lookup,
	.seekdir	= dir40_seekdir,
	.readdir	= dir40_readdir,
	.telldir	= dir40_telldir,

#ifndef ENABLE_MINIMAL
	.sdext_mandatory = (1 << SDEXT_LW_ID),
	.sdext_unknown   = (1 << SDEXT_SYMLINK_ID)
#endif
};