f2fs: issue discard with finally produced len and minlen

This patch determines to issue discard commands by comparing given minlen and
the length of produced final candidates.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/checkpoint.c

@@ -1043,7 +1043,7 @@ static void do_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
 	if (unlikely(f2fs_cp_error(sbi)))
 		return;
 
-	clear_prefree_segments(sbi);
+	clear_prefree_segments(sbi, cpc);
 	clear_sbi_flag(sbi, SBI_IS_DIRTY);
 }
 

fs/f2fs/f2fs.h

@@ -1628,7 +1628,7 @@ int create_flush_cmd_control(struct f2fs_sb_info *);
 void destroy_flush_cmd_control(struct f2fs_sb_info *);
 void invalidate_blocks(struct f2fs_sb_info *, block_t);
 void refresh_sit_entry(struct f2fs_sb_info *, block_t, block_t);
-void clear_prefree_segments(struct f2fs_sb_info *);
+void clear_prefree_segments(struct f2fs_sb_info *, struct cp_control *);
 void release_discard_addrs(struct f2fs_sb_info *);
 void discard_next_dnode(struct f2fs_sb_info *, block_t);
 int npages_for_summary_flush(struct f2fs_sb_info *, bool);

fs/f2fs/segment.c

@@ -552,10 +552,6 @@ static void add_discard_addrs(struct f2fs_sb_info *sbi, struct cp_control *cpc)
 			break;
 
 		end = __find_rev_next_zero_bit(dmap, max_blocks, start + 1);
-
-		if (force && end - start < cpc->trim_minlen)
-			continue;
-
 		__add_discard_entry(sbi, cpc, se, start, end);
 	}
 }
@@ -586,7 +582,7 @@ static void set_prefree_as_free_segments(struct f2fs_sb_info *sbi)
 	mutex_unlock(&dirty_i->seglist_lock);
 }
 
-void clear_prefree_segments(struct f2fs_sb_info *sbi)
+void clear_prefree_segments(struct f2fs_sb_info *sbi, struct cp_control *cpc)
 {
 	struct list_head *head = &(SM_I(sbi)->discard_list);
 	struct discard_entry *entry, *this;
@@ -619,7 +615,10 @@ void clear_prefree_segments(struct f2fs_sb_info *sbi)
 
 	/* send small discards */
 	list_for_each_entry_safe(entry, this, head, list) {
+		if (cpc->reason == CP_DISCARD && entry->len < cpc->trim_minlen)
+			goto skip;
 		f2fs_issue_discard(sbi, entry->blkaddr, entry->len);
+skip:
 		list_del(&entry->list);
 		SM_I(sbi)->nr_discards -= entry->len;
 		kmem_cache_free(discard_entry_slab, entry);
@@ -1061,8 +1060,7 @@ int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range)
 	unsigned int start_segno, end_segno;
 	struct cp_control cpc;
 
-	if (range->minlen > SEGMENT_SIZE(sbi) || start >= MAX_BLKADDR(sbi) ||
-						range->len < sbi->blocksize)
+	if (start >= MAX_BLKADDR(sbi) || range->len < sbi->blocksize)
 		return -EINVAL;
 
 	cpc.trimmed = 0;
@@ -1074,7 +1072,7 @@ int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range)
 	end_segno = (end >= MAX_BLKADDR(sbi)) ? MAIN_SEGS(sbi) - 1 :
 						GET_SEGNO(sbi, end);
 	cpc.reason = CP_DISCARD;
-	cpc.trim_minlen = F2FS_BYTES_TO_BLK(range->minlen);
+	cpc.trim_minlen = max_t(__u64, 1, F2FS_BYTES_TO_BLK(range->minlen));
 
 	/* do checkpoint to issue discard commands safely */
 	for (; start_segno <= end_segno; start_segno = cpc.trim_end + 1) {