There was a corner case where Etag returned would be incorrect. This
happens when the object is changed from file interface but with object
size remaining the same.
This change introduces an additional metadata that stores the mtime of
object during PUT. This stored mtime is compared with actual mtime
during GET to determine if the file has changed or not. Etag is
recalculated if the file has changed.
The scope of this fix in addressing the above mentioned corner case is
limited to new objects only. Also, refactoring the code further by
moving some methods from utils.py to classes in diskfile.py should
prevent some redundant (f)stat syscalls. These minor optimizations
will be addressed in a separate change.
Change-Id: If724697ef2b17a3c569b60bd81ebf98dab283da6
Signed-off-by: Prashanth Pai <ppai@redhat.com>
da53693c9b