fix overflow of dirsize; from FreeBSD; PR 6426; ok beck@ millert@

diff --git a/sys/ufs/ffs/ffs_alloc.c b/sys/ufs/ffs/ffs_alloc.c
index 36aaef3..881996c 100644 (file)
--- a/sys/ufs/ffs/ffs_alloc.c
+++ b/sys/ufs/ffs/ffs_alloc.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: ffs_alloc.c,v 1.88 2010/01/16 15:45:10 chl Exp $      */
+/*     $OpenBSD: ffs_alloc.c,v 1.89 2010/07/13 18:52:25 otto Exp $     */
 /*     $NetBSD: ffs_alloc.c,v 1.11 1996/05/11 18:27:09 mycroft Exp $   */
 
 /*
@@ -983,7 +983,10 @@ ffs_dirpref(struct inode *pip)
        curdirsize = avgndir ? (cgsize - avgbfree * fs->fs_bsize) / avgndir : 0;
        if (dirsize < curdirsize)
                dirsize = curdirsize;
-       maxcontigdirs = min(avgbfree * fs->fs_bsize  / dirsize, 255);
+       if (dirsize <= 0)
+               maxcontigdirs = 0;              /* dirsize overflowed */
+       else
+               maxcontigdirs = min(avgbfree * fs->fs_bsize  / dirsize, 255);
        if (fs->fs_avgfpdir > 0)
                maxcontigdirs = min(maxcontigdirs,
                                    fs->fs_ipg / fs->fs_avgfpdir);