f2fs: clarify and enhance the f2fs_gc flow

This patch makes clearer the ambiguous f2fs_gc flow as follows.

1. Remove intermediate checkpoint condition during f2fs_gc
 (i.e., should_do_checkpoint() and GC_BLOCKED)

2. Remove unnecessary return values of f2fs_gc because of #1.
 (i.e., GC_NODE, GC_OK, etc)

3. Simplify write_checkpoint() because of #2.

4. Clarify the main f2fs_gc flow.
 o monitor how many freed sections during one iteration of do_garbage_collect().
 o do GC more without checkpoints if we can't get enough free sections.
 o do checkpoint once we've got enough free sections through forground GCs.

5. Adopt thread-logging (Slack-Space-Recycle) scheme more aggressively on data
  log types. See. get_ssr_segement()

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

1 files changed, 3 insertions, 9 deletions

diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index 458bf5c726f7..552dadbb2327 100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -450,21 +450,15 @@ static inline bool need_SSR(struct f2fs_sb_info *sbi)
         return (free_sections(sbi) < overprovision_sections(sbi));
 }
 
-static inline int get_ssr_segment(struct f2fs_sb_info *sbi, int type)
-{
-        struct curseg_info *curseg = CURSEG_I(sbi, type);
-        return DIRTY_I(sbi)->v_ops->get_victim(sbi,
-                                &(curseg)->next_segno, BG_GC, type, SSR);
-}
-
-static inline bool has_not_enough_free_secs(struct f2fs_sb_info *sbi)
+static inline bool has_not_enough_free_secs(struct f2fs_sb_info *sbi, int freed)
 {
         int node_secs = get_blocktype_secs(sbi, F2FS_DIRTY_NODES);
         int dent_secs = get_blocktype_secs(sbi, F2FS_DIRTY_DENTS);
+
         if (sbi->por_doing)
                 return false;
 
-        return (free_sections(sbi) <= (node_secs + 2 * dent_secs +
+        return ((free_sections(sbi) + freed) <= (node_secs + 2 * dent_secs +
                                                 reserved_sections(sbi)));
 }