[PATCH 0/3] btrfs: remove unused return_any parameter from btrfs_search_slot_for_read()

[Sun YangKai <sunk67188@gmail.com>]

The return_any parameter in btrfs_search_slot_for_read() was designed
to allow falling back to the opposite search direction when no item
is found in the requested direction. However, analysis shows that:

- The vast majority of callers pass return_any=0, meaning the fallback
  logic is effectively dead code for the common case.
  
- The few callers that did pass return_any=1 were doing so unnecessarily

  - get_last_extent() in send.c: There is always a previous item (at
    minimum the inode_item) before an extent data item, making the fallback
    impossible to trigger.
    
  - btrfs_read_qgroup_config() in qgroup.c: When searching from the
    zeroed key (0,0,0) with find_higher=1, there cannot possibly be a
    lower key to fall back to, making return_any=1 logically nonsensical.

This series removes these unnecessary return_any=1 usages (patches 1-2),
then removes the now-unused parameter and associated dead code from
btrfs_search_slot_for_read() (patch 3).

The final result is a significantly simplified interface and implementation,
with no functional change for any existing code path.

Patch 1: Drop pointless return_any fallback in qgroup config reading
Patch 2: Drop unnecessary return_any search in send's get_last_extent()
Patch 3: Remove return_any parameter and simplify implementation

Sun YangKai (3):
  btrfs: qgroup: drop pointless return_any fallback when reading qgroup
    config
  btrfs: send: drop unnecessary return_any search in get_last_extent()
  btrfs: simplify btrfs_search_slot_for_read() by removing return_any
    parameter

 fs/btrfs/ctree.c           | 48 +++++++-------------------------------
 fs/btrfs/ctree.h           |  3 +--
 fs/btrfs/free-space-tree.c |  2 +-
 fs/btrfs/qgroup.c          | 10 ++++----
 fs/btrfs/send.c            | 22 ++++++++---------
 5 files changed, 25 insertions(+), 60 deletions(-)

-- 
2.52.0