ext2: Return more than a single dirent at a time in ext2_read_dir().

* similar to what mmlr did in hrev45575 for bfs.

src/add-ons/kernel/file_systems/ext2/DirectoryIterator.cpp

@@ -108,8 +108,8 @@ DirectoryIterator::Get(char* name, size_t* _nameLength, ino_t* _id)
 			entry->InodeID(), entry->Length(), length, entry->FileType());
 
 		if (*_nameLength > 0) {
-			if (*_nameLength < length)
+			if (length + 1 > *_nameLength)
-				length = *_nameLength - 1;
+				return B_BUFFER_OVERFLOW;
 
 			memcpy(name, entry->name, length);
 			name[length] = '\0';

src/add-ons/kernel/file_systems/ext2/kernel_interface.cpp

@@ -1414,27 +1414,44 @@ ext2_read_dir(fs_volume *_volume, fs_vnode *_node, void *_cookie,
 	struct dirent *dirent, size_t bufferSize, uint32 *_num)
 {
 	DirectoryIterator *iterator = (DirectoryIterator *)_cookie;
+	Volume* volume = (Volume*)_volume->private_volume;
 
-	size_t length = bufferSize;
+	uint32 maxCount = *_num;
+	uint32 count = 0;
+
+	while (count < maxCount && bufferSize > sizeof(struct dirent)) {
+
+		size_t length = bufferSize - sizeof(struct dirent) + 1;
 		ino_t id;
+
 		status_t status = iterator->GetNext(dirent->d_name, &length, &id);
-	if (status == B_ENTRY_NOT_FOUND) {
+		if (status == B_ENTRY_NOT_FOUND)
-		*_num = 0;
+			break;
-		return B_OK;
+
-	} else if (status != B_OK)
+		if (status == B_BUFFER_OVERFLOW) {
+			// the remaining name buffer length was too small
+			if (count == 0)
+				return B_BUFFER_OVERFLOW;
+			break;
+		}
+
+		if (status != B_OK)
 			return status;
 
 		status = iterator->Next();
 		if (status != B_OK && status != B_ENTRY_NOT_FOUND)
 			return status;
 		
-	Volume* volume = (Volume*)_volume->private_volume;
-
 		dirent->d_dev = volume->ID();
 		dirent->d_ino = id;
 		dirent->d_reclen = sizeof(struct dirent) + length;
 
-	*_num = 1;
+		bufferSize -= dirent->d_reclen;
+		dirent = (struct dirent*)((uint8*)dirent + dirent->d_reclen);
+		count++;
+	}
+
+	*_num = count;
 	return B_OK;
 }