f2fs: speed up defragment on sparse file

We have supported to get next page offset with valid mapping crossing
hole in f2fs_map_blocks, utilizing it to speed up defragment on sparse
file.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/data.c

@@ -1017,8 +1017,12 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
 					*map->m_next_pgofs = pgofs + 1;
 				goto sync_out;
 			}
-			if (flag != F2FS_GET_BLOCK_FIEMAP)
+			if (flag != F2FS_GET_BLOCK_FIEMAP) {
+				/* for defragment case */
+				if (map->m_next_pgofs)
+					*map->m_next_pgofs = pgofs + 1;
 				goto sync_out;
+			}
 		}
 	}
 

fs/f2fs/file.c

@@ -2071,10 +2071,10 @@ static int f2fs_defragment_range(struct f2fs_sb_info *sbi,
 					struct f2fs_defragment *range)
 {
 	struct inode *inode = file_inode(filp);
-	struct f2fs_map_blocks map = { .m_next_pgofs = NULL,
-			.m_next_extent = NULL, .m_seg_type = NO_CHECK_TYPE };
+	struct f2fs_map_blocks map = { .m_next_extent = NULL,
+					.m_seg_type = NO_CHECK_TYPE };
 	struct extent_info ei = {0,0,0};
-	pgoff_t pg_start, pg_end;
+	pgoff_t pg_start, pg_end, next_pgofs;
 	unsigned int blk_per_seg = sbi->blocks_per_seg;
 	unsigned int total = 0, sec_num;
 	block_t blk_end = 0;
@@ -2108,6 +2108,7 @@ static int f2fs_defragment_range(struct f2fs_sb_info *sbi,
 	}
 
 	map.m_lblk = pg_start;
+	map.m_next_pgofs = &next_pgofs;
 
 	/*
 	 * lookup mapping info in dnode page cache, skip defragmenting if all
@@ -2121,7 +2122,7 @@ static int f2fs_defragment_range(struct f2fs_sb_info *sbi,
 			goto out;
 
 		if (!(map.m_flags & F2FS_MAP_FLAGS)) {
-			map.m_lblk++;
+			map.m_lblk = next_pgofs;
 			continue;
 		}
 
@@ -2166,7 +2167,7 @@ static int f2fs_defragment_range(struct f2fs_sb_info *sbi,
 			goto clear_out;
 
 		if (!(map.m_flags & F2FS_MAP_FLAGS)) {
-			map.m_lblk++;
+			map.m_lblk = next_pgofs;
 			continue;
 		}