f2fs: fix wrong condition to trigger background checkpoint correctly

In f2fs_balance_fs_bg(), it needs to check both NAT_ENTRIES and INO_ENTRIES
memory usage to decide whether we should skip background checkpoint, otherwise
we may always skip checking INO_ENTRIES memory usage, so that INO_ENTRIES may
potentially cause high memory footprint.

Fixes: 493720a4 ("f2fs: fix to avoid REQ_TIME and CP_TIME collision")
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/segment.c

@@ -580,7 +580,7 @@ void f2fs_balance_fs_bg(struct f2fs_sb_info *sbi, bool from_bg)
 		goto do_sync;
 
 	/* checkpoint is the only way to shrink partial cached entries */
-	if (f2fs_available_free_memory(sbi, NAT_ENTRIES) ||
+	if (f2fs_available_free_memory(sbi, NAT_ENTRIES) &&
 		f2fs_available_free_memory(sbi, INO_ENTRIES))
 		return;