[PATCH] e2fsck: don't try to stop mmp if there is no superblock set up

[Eric Sandeen <sandeen@redhat.com>]

Under some failure cases, we can get to fatal_error()
without even having a superblock set up.  In that case,
ext2fs_mmp_stop() will segfault when it tries to dereference
fs->super.

Check for the existence of a superblock before we go
down the ext2fs_mmp_stop() path to avoid this problem.

Reported-by: Hubert Kario <hkario@redhat.com>
Addresses-Red-Hat-Bugzilla: #997972
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
---

diff --git a/e2fsck/util.c b/e2fsck/util.c
index 9eaf557..18005f4 100644
--- a/e2fsck/util.c
+++ b/e2fsck/util.c
@@ -55,7 +55,7 @@ void fatal_error(e2fsck_t ctx, const char *msg)
 		fprintf (stderr, "e2fsck: %s\n", msg);
 	if (!fs)
 		goto out;
-	if (fs->io) {
+	if (fs->io && fs->super) {
 		ext2fs_mmp_stop(ctx->fs);
 		if (ctx->fs->io->magic == EXT2_ET_MAGIC_IO_CHANNEL)
 			io_channel_flush(ctx->fs->io);