This is a note to let you know that I've just added the patch titled btrfs: Remove redundant extent_buffer_get in get_old_root to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: btrfs-remove-redundant-extent_buffer_get-in-get_old_.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 26cee799d11b5fa06dc2b0cfba0302a76dbf8564 Author: Nikolay Borisov <nborisov@xxxxxxxx> Date: Wed Aug 15 18:26:53 2018 +0300 btrfs: Remove redundant extent_buffer_get in get_old_root [ Upstream commit 6c122e2a0c515cfb3f3a9cefb5dad4cb62109c78 ] get_old_root used used only by btrfs_search_old_slot to initialise the path structure. The old root is always a cloned buffer (either via alloc dummy or via btrfs_clone_extent_buffer) and its reference count is 2: 1 from allocation, 1 from extent_buffer_get call in get_old_root. This latter explicit ref count acquire operation is in fact unnecessary since the semantic is such that the newly allocated buffer is handed over to the btrfs_path for lifetime management. Considering this just remove the extra extent_buffer_get in get_old_root. Signed-off-by: Nikolay Borisov <nborisov@xxxxxxxx> Reviewed-by: David Sterba <dsterba@xxxxxxxx> Signed-off-by: David Sterba <dsterba@xxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index b5ebb43b1824f..78d4c8c22b4ac 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -1430,7 +1430,6 @@ get_old_root(struct btrfs_root *root, u64 time_seq) if (!eb) return NULL; - extent_buffer_get(eb); btrfs_tree_read_lock(eb); if (old_root) { btrfs_set_header_bytenr(eb, eb->start);