Re: [PATCH] ext4: Fix buffer_head refcnt leak when ext4_iget() fails

[Theodore Y. Ts'o]

On Thu, Apr 23, 2020 at 01:09:27PM +0800, Xiyu Yang wrote:
> ext4_orphan_get() invokes ext4_read_inode_bitmap(), which returns a
> reference of the specified buffer_head object to "bitmap_bh" with
> increased refcnt.
> 
> When ext4_orphan_get() returns, local variable "bitmap_bh" becomes
> invalid, so the refcount should be decreased to keep refcount balanced.
> 
> The reference counting issue happens in one exception handling path of
> ext4_orphan_get(). When ext4_iget() fails, the function forgets to
> decrease the refcnt increased by ext4_read_inode_bitmap(), causing a
> refcnt leak.
> 
> Fix this issue by calling brelse() when ext4_iget() fails.
> 
> Signed-off-by: Xiyu Yang <xiyuyang19@xxxxxxxxxxxx>
> Signed-off-by: Xin Tan <tanxin.ctf@xxxxxxxxx>

Applied, thanks.

					- Ted