releases/2.6.31.8/0003-jbd2-Fail-to-load-a-journal-if-it-is-too-short.patch

From 558b413137123c701eda6e62d927bff476655e3c Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@suse.cz>
Date: Fri, 17 Jul 2009 10:40:01 -0400
Subject: [PATCH 03/85] jbd2: Fail to load a journal if it is too short

(cherry picked from commit f6f50e28f0cb8d7bcdfaacc83129f005dede11b1)

Due to on disk corruption, it can happen that journal is too short. Fail
to load it in such case so that we don't oops somewhere later.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
 fs/jbd2/journal.c |    6 ++++++
 1 file changed, 6 insertions(+)

--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -1187,6 +1187,12 @@ static int journal_reset(journal_t *jour
 
 	first = be32_to_cpu(sb->s_first);
 	last = be32_to_cpu(sb->s_maxlen);
+	if (first + JBD2_MIN_JOURNAL_BLOCKS > last + 1) {
+		printk(KERN_ERR "JBD: Journal too short (blocks %llu-%llu).\n",
+		       first, last);
+		journal_fail_superblock(journal);
+		return -EINVAL;
+	}
 
 	journal->j_first = first;
 	journal->j_last = last;