fs: allow lockless ->i_count bumps as long as it does not transition 0->1

With this change only 0->1 and 1->0 transitions need the lock.

I verified all places which look at the refcount either only care about
it staying 0 (and have the lock enforce it) or don't hold the inode lock
to begin with (making the above change irrelevant to their correcness or
lack thereof).

I also confirmed nfs and btrfs like to call into these a lot and now
avoid the lock in the common case, shaving off some atomics.

Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://patch.msgid.link/20260421182538.1215894-4-mjguzik@gmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>

0 files changed, 0 insertions, 0 deletions