f2fs: avoid unnecessary block mapping lookups in f2fs_read_data_large_folio

In the second call to f2fs_map_blocks within f2fs_read_data_large_folio,
map.m_len exceeds the logical address space to be read. This patch
ensures map.m_len does not exceed the required address space.

Signed-off-by: Yongpeng Yang <yangyongpeng@xiaomi.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Author: Yongpeng Yang

fs/f2fs/data.c

@@ -2468,7 +2468,7 @@ static int f2fs_read_data_large_folio(struct inode *inode,
 	ffs = NULL;
 	nrpages = folio_nr_pages(folio);
 
-	for (; nrpages; nrpages--) {
+	for (; nrpages; nrpages--, max_nr_pages--) {
 		sector_t block_nr;
 		/*
 		 * Map blocks using the previous result first.