Here we define each file set as those found by a recursive search of a
single directory argument to btrfs fi du.
This isn't as simple as adding up shared extents - they may be shared with
each other, and may also overlap. This patch uses an interval tree to store
shared extents we find while fiemapping files. After collecting them, a 'set
shared' count is calculated by summing (without overlap) each shared region
discovered. This is then displayed to the user as 'set shared'.
Signed-off-by: Mark Fasheh <mfasheh@suse.de>
Signed-off-by: David Sterba <dsterba@suse.com>
'btrfs du' differs from regular du in that it will work to resolve which
blocks are shared between files in its list. This gives the user a more
accurate bytecount from which they can make decisions regarding management
of their file space.
We still print a total number of bytes counted (like regular du), but also
print the number of bytes which were found to have been shared amongst the
file set provided. From there it becomes trivial to calculate how much space
is exclusively owned.
Signed-off-by: Mark Fasheh <mfasheh@suse.de>
[ rename files to reflect the filesystem command group, add GPL v2
file headers ]
Signed-off-by: David Sterba <dsterba@suse.com>
