[ Upstream commit 70a9ac36ffd807ac506ed0b849f3e8ce3c6623f2 ] Fix up a misuse that the filename pointer isn't always valid in the ring buffer, and we should copy the content instead. Fixes: 0c5e36db17f5 ("f2fs: trace f2fs_lookup") Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>