[3.16.y-ckt extended stable] Patch "ext4: fix oops when loading block bitmap failed" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    ext4: fix oops when loading block bitmap failed

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt1.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 811f6ccff7a93fdfd696d45e3b95df607d8c5409 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack at suse.cz>
Date: Thu, 30 Oct 2014 10:53:16 -0400
Subject: ext4: fix oops when loading block bitmap failed

commit 599a9b77ab289d85c2d5c8607624efbe1f552b0f upstream.

When we fail to load block bitmap in __ext4_new_inode() we will
dereference NULL pointer in ext4_journal_get_write_access(). So check
for error from ext4_read_block_bitmap().

Coverity-id: 989065
Signed-off-by: Jan Kara <jack at suse.cz>
Signed-off-by: Theodore Ts'o <tytso at mit.edu>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 fs/ext4/ialloc.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 8012a5daf401..ac644c31ca67 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -887,6 +887,10 @@ got:
 		struct buffer_head *block_bitmap_bh;

 		block_bitmap_bh = ext4_read_block_bitmap(sb, group);
+		if (!block_bitmap_bh) {
+			err = -EIO;
+			goto out;
+		}
 		BUFFER_TRACE(block_bitmap_bh, "get block bitmap access");
 		err = ext4_journal_get_write_access(handle, block_bitmap_bh);
 		if (err) {
--
2.1.0