Extensible files | CS 162 Project 3

Pintos currently cannot extend the size of files because the Pintos file system allocates each file as a single contiguous set of blocks. Your task is to modify the Pintos file system to support extending files. Your design should provide fast random accesses to the file, so you should avoid using a design based on File Allocation Tables (FAT). One possibility is to use an indexed inode structure with direct, indirect, and doubly-indirect pointers, similar to Unix FFS. The maximum file size you need to support is 8 MiB (2^23 bytes). You must also add support for a new system call inumber(int fd) which returns the unique inode number of file associated with a particular file descriptor. Make sure that you gracefully handle cases where the operating system runs out of memory or disk space by leaving the file system in a consistent state (especially with regard to inode extension) and without leaking disk space or memory. The basic file system allocates files as a single extent, making it

saved by

• Ayushi Batwara