Question

What system call causes getattr() in memoryll.py to be called (on files in a memoryll filesystem)? How did you verify this?

Answer 1

Solution:

Use of getattr() and when it's get called ?

getattr() here is used to get the statistics of a file or directory.
getattr() is getting called when any operation has been made on file system.
These operations are open(), read(), readdir(), write() etc.

How to verify if getattr() is getting called ?
First put one print statement inside getattr() like below:
def getattr(self, req, ino, fi):
print 'getattr:', ino // Put a print statement like written here
attr = self.attr[ino]
if attr:
self.reply_attr(req, attr, 1.0)
else:
self.reply_err(req, ENOENT)

Then, you can verify this by calling any of above operation mentioned above. After calling any of above function, if you check logs, you will find that information printed.