Write last disk sector, not last 512-byte block, when testing validity

of new partition limit.

Fixes growfs on 4K-sector disks.

Reported by and fix tested by David Vasek via misc@.

diff --git a/sbin/growfs/growfs.c b/sbin/growfs/growfs.c
index df836fc..2911caf 100644 (file)
--- a/sbin/growfs/growfs.c
+++ b/sbin/growfs/growfs.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: growfs.c,v 1.33 2013/11/10 00:48:04 krw Exp $ */
+/*     $OpenBSD: growfs.c,v 1.34 2014/04/30 14:28:48 krw Exp $ */
 /*
  * Copyright (c) 2000 Christoph Herrmann, Thomas-Henning von Kamptz
  * Copyright (c) 1980, 1989, 1993 The Regents of the University of California.
@@ -1899,7 +1899,7 @@ int
 main(int argc, char **argv)
 {
        DBG_FUNC("main")
-       char    *device;
+       char    *device, *lastsector;
        int     ch;
        long long       size = 0;
        unsigned int    Nflag = 0;
@@ -2072,12 +2072,16 @@ main(int argc, char **argv)
                    (intmax_t)sblock.fs_size);
 
        /*
-        * Try to access our new last block in the filesystem. Even if we
-        * later on realize we have to abort our operation, on that block
+        * Try to access our new last sector in the filesystem. Even if we
+        * later on realize we have to abort our operation, on that sector
         * there should be no data, so we can't destroy something yet.
         */
-       wtfs(DL_SECTOBLK(lp, DL_GETPSIZE(pp)) - 1, (size_t)DEV_BSIZE,
-           (void *)&sblock, fso, Nflag);
+       lastsector = calloc(1, lp->d_secsize);
+       if (!lastsector)
+               err(1, "No memory for last sector test write");
+       wtfs(DL_SECTOBLK(lp, DL_GETPSIZE(pp) - 1), lp->d_secsize,
+           lastsector, fso, Nflag);
+       free(lastsector);
 
        /*
         * Now calculate new superblock values and check for reasonable