src/sys/fs/nullfs, branch main

VOP_RENAME(9): add flags argument

2026-03-05T23:46:53+00:00

Reviewed by:	markj
Tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D55539

nullfs: Fix handling of doomed vnodes in nullfs_unlink_lowervp()

2026-02-25T15:31:30+00:00

nullfs_unlink_lowervp() is called with the lower vnode locked, so the
nullfs vnode is locked too.  The following can occur:
1. the vunref() call decrements the usecount 2->1,
2. a different thread calls vrele() on the vnode, decrements the
   usecount 0->1, then blocks on the vnode lock,
3. the first thread tests vp->v_usecount == 0 and observes that it is
   true,
4. the first thread incorrectly unlocks the lower vnode.

Fix this by testing VN_IS_DOOMED directly.  Since
nullfs_unlink_lowervp() holds the vnode lock, the value of the
VIRF_DOOMED flag is stable.

Thanks to leres@ for patiently helping to track this down.

PR:		288345
MFC after:	1 week
Reviewed by:	kib
Differential Revision:	https://reviews.freebsd.org/D55446

nullfs: add nounixbypass mount option

2025-10-09T22:47:36+00:00

The option, when set, disables bypassing the unix socket vnode down
to the lower mp, effectively preventing connection to nullfs unix
socket from being acceptable from the lower mp (and vice versa).

This is done by providing a vop vector that stops bypass for unp-related
VOPs.  I believe that VFS_VOP_VECTOR_REGISTER() does the right thing
there regardless of the order of initialization.

Reviewed by:	markj
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D52983

nullfs_mount: use symbols instead of string literals for cache mount options

2025-10-09T22:47:22+00:00

Reviewed by:	markj
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D52983

nullfs: add a helper for testing if vnode belongs to a nullfs mount

2025-10-09T22:47:05+00:00

Reviewed by:	markj
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D52983

fs/nullfs/null.h: put first definition after headers include

2025-10-09T22:46:40+00:00

Reviewed by:	markj
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D52983

nullfs: fix up build with INVARIANTS after previous

2025-10-06T19:22:29+00:00

nullfs: shrink null_node to 32 bytes

2025-10-06T18:23:01+00:00

nullfs: Slightly reduce contention by reducing concurrent sections

2025-10-06T15:21:45+00:00

In null_lock_prep_with_smr(), initialize 'lvp' outside of the
SMR-protected section.

In null_lock(), if after locking the lower vnode we notice that we have
been reclaimed, we have to unlock the lower vnode and then relock our
own now that the lock isn't shared anymore.  Call VOP_UNLOCK() on the
lower vnode as soon as this condition is known.

This applies comments from D38761, one of which was missed and the other
added too late.

Reviewed by:    kib
MFC with:       641a58239520 ("nullfs: avoid the interlock in null_lock with smr")
Sponsored by:   The FreeBSD Foundation
Differential Revision:  https://reviews.freebsd.org/D52935

nullfs: Fix some style after recent changes

2025-10-06T15:21:40+00:00

In 'nullfs_subr.c':
- Sort the headers.
- Use '__func__' in preference to the function's name in an assertion.

This applies comments from D38761, one of which was missed and the other
added too late.

Reviewed by:    kib
MFC with:       249ec85352b5 ("nullfs: smr-protected hash lookup")
Sponsored by:   The FreeBSD Foundation
Differential Revision:  https://reviews.freebsd.org/D52935