[PATCH v2 0/3] btrfs: search_tree ioctl performance improvements and cleanups

[Sun YangKai <sunk67188@gmail.com>]

This series optimizes the search_tree ioctl path used by tools like
compsize and cleans up related code:

Patch 1: Narrow loop variable scope

Patch 2: Early exit for out-of-range keys

    Replace continue with early exit when keys exceed max_key

    Provide measurable performance improvements:
    Cold cache: 34.61s → 30.40s (about 12% improvement)
    Hot cache: 14.19s → 10.57s (about 25% improvement)

Patch 3: Simplify key range checking

    Replace key_in_sk() helper with direct comparisons

    Add ASSERT for min_key validation (safe due to forward search)

    Maintain equivalent functionality with cleaner implementation

These changes optimize a critical path for filesystem analysis tools while
improving code maintainability. The performance gains are particularly
noticeable when scanning large filesystems.

Thanks,
Sun YangKai

---

Changes since v1:

* Replace the WARN_ON with ASSERT, since the condition is a runtime error.
  Suggested by David Sterba.

---

Sun YangKai (3):
  btrfs: narrow loop variable scope in copy_to_sk()
  btrfs: early exit the searching process in search_tree ioctl
  btrfs: replace key_in_sk() with a simple btrfs_key compare

 fs/btrfs/ioctl.c | 55 +++++++++++++++++-------------------------------
 1 file changed, 19 insertions(+), 36 deletions(-)

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2.50.0