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@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Nikolay Borisov 2018-08-15 18:26:53 +03:00 committed by Greg Kroah-Hartman
parent 4e989d243e
commit a2c79a9f15

View File

@ -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);