[hackers] [ubase][PATCH] df: Fix value in Avail column

[Mattias Andrée]

Free df(1) POSIX man page:

       <total space>
                 [...] <space used>, <space free>, plus any space reserved
                 by the system not normally available to a user.

       <space free>
                 [...] for the creation of new files by unprivileged users, 
[...]

Note, Capacity remains unchanged because it shall be

       <space used>/(<space used> + <space free>)

and it is maid explicitly clear that <space used> + <space free> shall not be 
<total space>:

       [...] This percentage may be greater than 100 if <space free> is less 
than zero [...]

Signed-off-by: Mattias Andrée <maand...@kth.se>
---
 df.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/df.c b/df.c
index 4d595d6..245cca3 100644
--- a/df.c
+++ b/df.c
@@ -65,8 +65,8 @@ mnt_show(const char *fsname, const char *dir)
 
        bs = s.f_frsize / blksize;
        total = s.f_blocks * bs;
-       avail = s.f_bfree * bs;
-       used = total - avail;
+       avail = s.f_bavail * bs;
+       used = total - s.f_bfree * bs;
 
        if (used + avail) {
                capacity = (used * 100) / (used + avail);
-- 
2.24.0