[PATCH 3/4] omfs: refuse to mount if bitmap pointer is obviously wrong

[Bob Copeland <me@bobcopeland.com>]

If the free space bitmap pointer is corrupted such that it lies outside
of the number of blocks in the filesystem, print a message and fail the
mount so the user can fix it offline.

Signed-off-by: Bob Copeland <me@bobcopeland.com>
---
 fs/omfs/inode.c |    9 +++++++++
 1 files changed, 9 insertions(+), 0 deletions(-)

diff --git a/fs/omfs/inode.c b/fs/omfs/inode.c
index bd4bf75..0af5d0a 100644
--- a/fs/omfs/inode.c
+++ b/fs/omfs/inode.c
@@ -509,6 +509,15 @@ static int omfs_fill_super(struct super_block *sb, void *data, int silent)
 		goto out_brelse_bh2;
 	}
 
+	if (sbi->s_bitmap_ino != ~0ULL &&
+	    sbi->s_bitmap_ino > sbi->s_num_blocks) {
+		printk(KERN_ERR "omfs: free space bitmap location is corrupt "
+			"(%llx, total blocks %llx)\n",
+			(unsigned long long) sbi->s_bitmap_ino,
+			(unsigned long long) sbi->s_num_blocks);
+		goto out_brelse_bh2;
+	}
+
 	ret = omfs_get_imap(sb);
 	if (ret)
 		goto out_brelse_bh2;
-- 
1.5.6.5