f2fs: Fix mount failure due to SPO after a successful online resize FS

Even though online resize is successfully done, a SPO immediately
after resize, still causes below error in the next mount.

[   11.294650] F2FS-fs (sda8): Wrong user_block_count: 2233856
[   11.300272] F2FS-fs (sda8): Failed to get valid F2FS checkpoint

This is because after FS metadata is updated in update_fs_metadata()
if the SBI_IS_DIRTY is not dirty, then CP will not be done to reflect
the new user_block_count.
Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/gc.c

@@ -1578,11 +1578,17 @@ int f2fs_resize_fs(struct f2fs_sb_info *sbi, __u64 block_count)
 		goto out;
 	}
 
+	mutex_lock(&sbi->cp_mutex);
 	update_fs_metadata(sbi, -secs);
 	clear_sbi_flag(sbi, SBI_IS_RESIZEFS);
+	set_sbi_flag(sbi, SBI_IS_DIRTY);
+	mutex_unlock(&sbi->cp_mutex);
+
 	err = f2fs_sync_fs(sbi->sb, 1);
 	if (err) {
+		mutex_lock(&sbi->cp_mutex);
 		update_fs_metadata(sbi, secs);
+		mutex_unlock(&sbi->cp_mutex);
 		update_sb_metadata(sbi, secs);
 		f2fs_commit_super(sbi, false);
 	}