[3.16.y-ckt stable] Patch "Btrfs: use kmem_cache_free when freeing entry in inode cache" has been added to staging queue

[Luis Henriques]

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

    Btrfs: use kmem_cache_free when freeing entry in inode cache

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/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt16.

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 660fe0d6a207e356f5595ad01c51237a79c1e6fe Mon Sep 17 00:00:00 2001
From: Filipe Manana <fdmanana at suse.com>
Date: Sat, 13 Jun 2015 06:52:56 +0100
Subject: Btrfs: use kmem_cache_free when freeing entry in inode cache

commit c3f4a1685bb87e59c886ee68f7967eae07d4dffa upstream.

The free space entries are allocated using kmem_cache_zalloc(),
through __btrfs_add_free_space(), therefore we should use
kmem_cache_free() and not kfree() to avoid any confusion and
any potential problem. Looking at the kfree() definition at
mm/slab.c it has the following comment:

  /*
   * (...)
   *
   * Don't free memory not originally allocated by kmalloc()
   * or you will run into trouble.
   */

So better be safe and use kmem_cache_free().

Signed-off-by: Filipe Manana <fdmanana at suse.com>
Reviewed-by: David Sterba <dsterba at suse.cz>
Signed-off-by: Chris Mason <clm at fb.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 fs/btrfs/inode-map.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/btrfs/inode-map.c b/fs/btrfs/inode-map.c
index 888fbe19079f..f25c68d84811 100644
--- a/fs/btrfs/inode-map.c
+++ b/fs/btrfs/inode-map.c
@@ -271,7 +271,7 @@ void btrfs_unpin_free_ino(struct btrfs_root *root)
 		__btrfs_add_free_space(ctl, info->offset, count);
 free:
 		rb_erase(&info->offset_index, rbroot);
-		kfree(info);
+		kmem_cache_free(btrfs_free_space_cachep, info);
 	}
 }