Can be fetched from github: https://github.com/adam900710/linux/tree/refactor_find_free_extent
Which is based on v4.19-rc1. extent-tree.c::find_free_extent() could be one of the most ill-structured functions, it has at least 6 non-exit tags and jumps between them. Refactor it into 4 parts: 1) find_free_extent() The main entrance, does the main work of block group iteration and block group selection. Now this function doesn't care nor handles free extent search by itself. 2) find_free_extent_clustered() Do clustered free extent search. May try to build/re-fill cluster. 3) find_free_extent_unclustered() Do unclustered free extent search. May try to fill free space cache. 4) find_free_extent_update_loop() Do the loop based black magic. May allocate new chunk. With this patch, at least we should make find_free_extent() a little easier to read, and provides the basis for later work on this function. Current refactor is trying not to touch the original functionality, thus the helper structure find_free_extent_ctl still contains a lot of unrelated members. But it should not change how find_free_extent() works at all. changelog: v2: Split into 4 patches. Minor comment newline change. v3: Mostly cosmetic update. Rebased to v4.19-rc1 Rename find_free_extent_ctrl to find_free_extent_ctl to keep the naming scheme the same. Fix some comment spelling error. Enhance comment for find_free_extent_unclustered(). Add reviewed-by tag. Qu Wenruo (4): btrfs: Introduce find_free_extent_ctl structure for later rework btrfs: Refactor clustered extent allocation into find_free_extent_clustered() btrfs: Refactor unclustered extent allocation into find_free_extent_unclustered() btrfs: Refactor find_free_extent() loops update into find_free_extent_update_loop() fs/btrfs/extent-tree.c | 702 ++++++++++++++++++++++++----------------- 1 file changed, 404 insertions(+), 298 deletions(-) -- 2.19.1