f2fs: retry gc if one section is not successfully reclaimed

If FG_GC failed to reclaim one section, let's retry with another section
from the start, since we can get anoterh good candidate.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 0a5d573e2574f24d07c5222d4d732fbbdfba91fe..782b8e72c094a8ef3a04b20f7be76e3519931715 100644 (file)
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -391,7 +391,7 @@ static int check_valid_map(struct f2fs_sb_info *sbi,
  * On validity, copy that node with cold status, otherwise (invalid node)
  * ignore that.
  */
-static void gc_node_segment(struct f2fs_sb_info *sbi,
+static int gc_node_segment(struct f2fs_sb_info *sbi,
                struct f2fs_summary *sum, unsigned int segno, int gc_type)
 {
        bool initial = true;
@@ -411,7 +411,7 @@ next_step:
 
                /* stop BG_GC if there is not enough free sections. */
                if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0))
-                       return;
+                       return 0;
 
                if (check_valid_map(sbi, segno, off) == 0)
                        continue;
@@ -461,13 +461,11 @@ next_step:
                };
                sync_node_pages(sbi, 0, &wbc);
 
-               /*
-                * In the case of FG_GC, it'd be better to reclaim this victim
-                * completely.
-                */
-               if (get_valid_blocks(sbi, segno, 1) != 0)
-                       goto next_step;
+               /* return 1 only if FG_GC succefully reclaimed one */
+               if (get_valid_blocks(sbi, segno, 1) == 0)
+                       return 1;
        }
+       return 0;
 }
 
 /*
@@ -649,7 +647,7 @@ out:
  * If the parent node is not valid or the data block address is different,
  * the victim data block is ignored.
  */
-static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
+static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
                struct gc_inode_list *gc_list, unsigned int segno, int gc_type)
 {
        struct super_block *sb = sbi->sb;
@@ -672,7 +670,7 @@ next_step:
 
                /* stop BG_GC if there is not enough free sections. */
                if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0))
-                       return;
+                       return 0;
 
                if (check_valid_map(sbi, segno, off) == 0)
                        continue;
@@ -737,15 +735,11 @@ next_step:
        if (gc_type == FG_GC) {
                f2fs_submit_merged_bio(sbi, DATA, WRITE);
 
-               /*
-                * In the case of FG_GC, it'd be better to reclaim this victim
-                * completely.
-                */
-               if (get_valid_blocks(sbi, segno, 1) != 0) {
-                       phase = 2;
-                       goto next_step;
-               }
+               /* return 1 only if FG_GC succefully reclaimed one */
+               if (get_valid_blocks(sbi, segno, 1) == 0)
+                       return 1;
        }
+       return 0;
 }
 
 static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
@@ -761,12 +755,13 @@ static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
        return ret;
 }
 
-static void do_garbage_collect(struct f2fs_sb_info *sbi, unsigned int segno,
+static int do_garbage_collect(struct f2fs_sb_info *sbi, unsigned int segno,
                                struct gc_inode_list *gc_list, int gc_type)
 {
        struct page *sum_page;
        struct f2fs_summary_block *sum;
        struct blk_plug plug;
+       int nfree = 0;
 
        /* read segment summary of victim */
        sum_page = get_sum_page(sbi, segno);
@@ -786,10 +781,11 @@ static void do_garbage_collect(struct f2fs_sb_info *sbi, unsigned int segno,
 
        switch (GET_SUM_TYPE((&sum->footer))) {
        case SUM_TYPE_NODE:
-               gc_node_segment(sbi, sum->entries, segno, gc_type);
+               nfree = gc_node_segment(sbi, sum->entries, segno, gc_type);
                break;
        case SUM_TYPE_DATA:
-               gc_data_segment(sbi, sum->entries, gc_list, segno, gc_type);
+               nfree = gc_data_segment(sbi, sum->entries, gc_list,
+                                                       segno, gc_type);
                break;
        }
        blk_finish_plug(&plug);
@@ -798,6 +794,7 @@ static void do_garbage_collect(struct f2fs_sb_info *sbi, unsigned int segno,
        stat_inc_call_count(sbi->stat_info);
 
        f2fs_put_page(sum_page, 0);
+       return nfree;
 }
 
 int f2fs_gc(struct f2fs_sb_info *sbi)
@@ -836,13 +833,10 @@ gc_more:
                                                                META_SSA);
 
        for (i = 0; i < sbi->segs_per_sec; i++)
-               do_garbage_collect(sbi, segno + i, &gc_list, gc_type);
+               nfree += do_garbage_collect(sbi, segno + i, &gc_list, gc_type);
 
-       if (gc_type == FG_GC) {
+       if (gc_type == FG_GC)
                sbi->cur_victim_sec = NULL_SEGNO;
-               nfree++;
-               WARN_ON(get_valid_blocks(sbi, segno, sbi->segs_per_sec));
-       }
 
        if (has_not_enough_free_secs(sbi, nfree))
                goto gc_more;