jbd2: Fail to load a journal if it is too short

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>

diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index e378cb383979a3e8e54234b14aa354e890c54e26..a8a358bc0f21792f5f675889f63d0c4123ecc04d 100644 (file)
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -1187,6 +1187,12 @@ static int journal_reset(journal_t *journal)
 
        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;