btrfs-progs: device usage: report slack space

The total filesystem space on a given device might be smaller than the
device size. We should report that space as well. The original idea was
to report the 'occupied' size but the term was not all clear, so the
logic was reversed to report the slack space.

Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/cmds-fi-usage.c b/cmds-fi-usage.c
index 2382006..b26ece1 100644 (file)
--- a/cmds-fi-usage.c
+++ b/cmds-fi-usage.c
@@ -1024,13 +1024,8 @@ void print_device_sizes(int fd, struct device_info *devinfo, unsigned unit_mode)
        printf("   Device size: %*s%10s\n",
                (int)(20 - strlen("Device size")), "",
                pretty_size_mode(devinfo->device_size, unit_mode));
-#if 0
-       /*
-        * The term has not seen an agreement and we don't want to change it
-        * once it's in non-development branches or even released.
-        */
-       printf("   FS occupied: %*s%10s\n",
-               (int)(20 - strlen("FS occupied")), "",
-               pretty_size_mode(devinfo->size, unit_mode));
-#endif
+       printf("   Device slack: %*s%10s\n",
+               (int)(20 - strlen("Device slack")), "",
+               pretty_size_mode(devinfo->device_size - devinfo->size,
+                       unit_mode));
 }