kern/43573: ffs superblock search prevents mounting tiny file systems

[pooka%iki.fi@localhost]

>Number:         43573
>Category:       kern
>Synopsis:       ffs superblock search prevents mounting tiny file systems
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Jul 05 17:05:00 +0000 2010
>Originator:     Antti Kantee
>Release:        
>Organization:
>Environment:
>Description:
As reported by hubertf, a really tiny ffs file system will fail
to mount with EINVAL.
>How-To-Repeat:
mount tiny_ffs /mnt
>Fix:
maybe this, although I haven't done any critical thinking about it.

Index: ffs_vfsops.c
===================================================================
RCS file: /cvsroot/src/sys/ufs/ffs/ffs_vfsops.c,v
retrieving revision 1.259
diff -p -u -r1.259 ffs_vfsops.c
--- ffs_vfsops.c        24 Jun 2010 13:03:19 -0000      1.259
+++ ffs_vfsops.c        5 Jul 2010 16:47:28 -0000
@@ -878,8 +878,7 @@ ffs_mountfs(struct vnode *devvp, struct 
                error = bread(devvp, sblock_try[i] / DEV_BSIZE, SBLOCKSIZE, 
cred,
                              0, &bp);
                if (error) {
-                       fs = NULL;
-                       goto out;
+                       continue;
                }
                fs = (struct fs*)bp->b_data;
                fsblockloc = sblockloc = sblock_try[i];