[4.2.y-ckt stable] Patch "dm btree: fix leak of bufio-backed block in btree_split_sibling error path" has been added to staging queue

[Kamal Mostafa]

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

    dm btree: fix leak of bufio-backed block in btree_split_sibling error path

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-ckt2.

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

For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

>From 71d6f0aa0ed282e3b9d2400da3f2d614dff309e6 Mon Sep 17 00:00:00 2001
From: Mike Snitzer <snitzer at redhat.com>
Date: Mon, 23 Nov 2015 16:24:45 -0500
Subject: dm btree: fix leak of bufio-backed block in btree_split_sibling error
 path

commit 30ce6e1cc5a0f781d60227e9096c86e188d2c2bd upstream.

The block allocated at the start of btree_split_sibling() is never
released if later insert_at() fails.

Fix this by releasing the previously allocated bufio block using
unlock_block().

Reported-by: Mikulas Patocka <mpatocka at redhat.com>
Signed-off-by: Mike Snitzer <snitzer at redhat.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/md/persistent-data/dm-btree.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/md/persistent-data/dm-btree.c b/drivers/md/persistent-data/dm-btree.c
index d6e4703..7ba85e2 100644
--- a/drivers/md/persistent-data/dm-btree.c
+++ b/drivers/md/persistent-data/dm-btree.c
@@ -471,8 +471,10 @@ static int btree_split_sibling(struct shadow_spine *s, dm_block_t root,

 	r = insert_at(sizeof(__le64), pn, parent_index + 1,
 		      le64_to_cpu(rn->keys[0]), &location);
-	if (r)
+	if (r) {
+		unlock_block(s->info, right);
 		return r;
+	}

 	if (key < le64_to_cpu(rn->keys[0])) {
 		unlock_block(s->info, right);
--
1.9.1