$1.$ This assignment is a pair programming effort. It is due on $4/26/2024.$ Use only xv$6-$riscv.

$2.$ Purpose: Add extent$-$based files to the xv$6$ file system. An extent is a $($pointer$,$ length$)$ pair. The pointer points to a sector address; the length indicates how many consecutive blocks are occupied by that extent. Operations on large extent$-$based files are faster than the pointer$-$based files that xv$6$ have now.

$3.$ Requirements:

$1)(10\%)$ Add an O$\_$EXTENT flag to the open$()$ system call that will create an extent based file.

$2)(10\%)$ Modify the fstat$()$ system call such that it will dump information about each extent of an extent based file in addition to file size, etc.

$3)(15\%)$ Add the new system call lseek$()$ which takes a file descriptor and an integer offset as arguments. It sets the current offset of the open file to the specified offset upon success. lseek$()$ can fail. You will specify its error return interface. Application programs can use this to read or write arbitrary locations within a file. Your lseek$()$ should work with both extend$-$based and pointer$-$based files.

You will need to modify the data block allocation and deallocation function bmap$()$ in the file system. Describe and discuss your block allocation and deallocation methods.