Re: [PATCH] fs: prevent data-race due to missing inode_lock when calling vfs_getattr

On Mon, Nov 18, 2024 at 01:37:19AM +0900, Jeongjun Park wrote:

Many filesystems lock inodes before calling vfs_getattr, so there is no data-race for inodes. However, some functions in fs/stat.c that call vfs_getattr do not lock inodes, so the data-race occurs.

Therefore, we need to apply a patch to remove the long-standing data-race for inodes in some functions that do not lock inodes.

Why do we care? Slapping even a shared lock on a _very_ hot path, with possible considerable latency, would need more than "theoretically it's a data race".