On Wed, Apr 10, 2019 at 10:06:57PM +0100, Al Viro wrote: > On Wed, Apr 10, 2019 at 01:21:14PM -0700, Eric Biggers wrote: > > From: Eric Biggers <ebiggers@xxxxxxxxxx> > > > > Use 'READ_ONCE(inode->i_link)' to explicitly support filesystems caching > > the symlink target in ->i_link later if it was unavailable at iget() > > time, or wasn't easily available. I'll be doing this in fscrypt, to > > improve the performance of encrypted symlinks on ext4, f2fs, and ubifs. > > > > ->i_link will start NULL and may later be set to a non-NULL value by a > > smp_store_release() or cmpxchg_release(). READ_ONCE() is needed on the > > read side. smp_load_acquire() is unnecessary because only a data > > dependency barrier is required. (Thanks to Al for pointing this out.) > > You've missed vfs_readlink()... How so? The patch already updates vfs_readlink(). - Eric
