From 51ea8b57b8ebcda1ec47bb86567ff0661ddfca7b Mon Sep 17 00:00:00 2001
From: Bruce Evans <bde@FreeBSD.org>
Date: Sun, 14 Jan 1996 18:55:09 +0000
Subject: [PATCH] Partially fixed negative and truncated "Avail" counts in df
 output. This fixes PR943.

ffs/ffs_vfsops.c:
ffs_statfs() multiplied by (100 - minfree) as part of calculating the
minfree percentage (complemented in 100%), so with the standard minfree
of 8, it was broken for file systems of size >= 1TB/92 = 11GB.  Use the
standard freespace() macro instead.  This also fixes a rounding bug (the
"Avail" count was sometimes 1 too small).

ffs/* (not fixed):
The freespace() macro multiplies by minfree, so with the standard
minfree of 8, it is broken for file systems of size >= 1TB/8 = 128GB.
This bug is more serious since it affects block allocation.

ffs/ffs_alloc.c (not fixed):
Ordinary users are sometimes allowed to allocate 1 (partial) block
too many so that the "Avail" count goes negative.  E.g., if there is
1 fragment available and the file is fairly large, one more full
block is allocated.

df/df.c:
ufs_df() used/uses essentially the same code as ffs_statfs(), so it
had/has the same bugs.

ufs_df() gratuitously replaced "Avail" counts of < 0 by 0, so it
gave different results for non-mounted file systems in this case.
---
 bin/df/df.c              | 7 ++-----
 sys/ufs/ffs/ffs_vfsops.c | 5 ++---
 2 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/bin/df/df.c b/bin/df/df.c
index 80cbba4abe1..701a9adac46 100644
--- a/bin/df/df.c
+++ b/bin/df/df.c
@@ -35,7 +35,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id: df.c,v 1.6 1995/03/19 13:28:15 joerg Exp $
+ *	$Id: df.c,v 1.7 1995/05/30 00:06:42 rgrimes Exp $
  */
 
 #ifndef lint
@@ -386,10 +386,7 @@ ufs_df(file, maxwidth)
 	sfsp->f_blocks = sblock.fs_dsize;
 	sfsp->f_bfree = sblock.fs_cstotal.cs_nbfree * sblock.fs_frag +
 		sblock.fs_cstotal.cs_nffree;
-	sfsp->f_bavail = (sblock.fs_dsize * (100 - sblock.fs_minfree) / 100) -
-		(sblock.fs_dsize - sfsp->f_bfree);
-	if (sfsp->f_bavail < 0)
-		sfsp->f_bavail = 0;
+	sfsp->f_bavail = freespace(&sblock, sblock.fs_minfree);
 	sfsp->f_files =  sblock.fs_ncg * sblock.fs_ipg;
 	sfsp->f_ffree = sblock.fs_cstotal.cs_nifree;
 	sfsp->f_fsid.val[0] = 0;
diff --git a/sys/ufs/ffs/ffs_vfsops.c b/sys/ufs/ffs/ffs_vfsops.c
index 203a535b7ba..e3107084d37 100644
--- a/sys/ufs/ffs/ffs_vfsops.c
+++ b/sys/ufs/ffs/ffs_vfsops.c
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)ffs_vfsops.c	8.8 (Berkeley) 4/18/94
- * $Id: ffs_vfsops.c,v 1.32 1995/12/17 21:09:35 phk Exp $
+ * $Id: ffs_vfsops.c,v 1.33 1996/01/05 18:31:49 wollman Exp $
  */
 
 #include "opt_quota.h"
@@ -728,8 +728,7 @@ ffs_statfs(mp, sbp, p)
 	sbp->f_blocks = fs->fs_dsize;
 	sbp->f_bfree = fs->fs_cstotal.cs_nbfree * fs->fs_frag +
 		fs->fs_cstotal.cs_nffree;
-	sbp->f_bavail = (fs->fs_dsize * (100 - fs->fs_minfree) / 100) -
-		(fs->fs_dsize - sbp->f_bfree);
+	sbp->f_bavail = freespace(fs, fs->fs_minfree);
 	sbp->f_files =  fs->fs_ncg * fs->fs_ipg - ROOTINO;
 	sbp->f_ffree = fs->fs_cstotal.cs_nifree;
 	if (sbp != &mp->mnt_stat) {