src/sys/fs/unionfs, branch main

VOP_RENAME(9): add flags argument

2026-03-05T23:46:53Z

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

Remove the DEBUG_VFS_LOCKS kernel option

2026-01-15T13:50:20Z

After commit 3bd8fab2415b ("vfs: Move DEBUG_VFS_LOCKS checks to INVARIANTS"), this option has no effect. Let's finish the removal. There are a couple of additional uses in zfs, I will submit a separate patch upstream for them. Reviewed by: mckusick, kib Differential Revision: https://reviews.freebsd.org/D54662

unionfs: Sporadic cleanup

2025-12-17T22:46:04Z

Sponsored by: Klara, Inc. Sponsored by: NetApp, Inc.

unionfs: Support renaming symbolic links

2025-12-17T22:40:59Z

This adds support for renaming a symbolic link found on the lower fs, which necessitates copying it to the upper fs, as well as basic tests. MFC after: 1 week Sponsored by: Klara, Inc. Sponsored by: NetApp, Inc. Reviewed by: olce, siderop1_netapp.com, jah Differential Revision: https://reviews.freebsd.org/D54229

unionfs: detect common deadlock-producing mount misconfigurations

2025-12-12T06:32:05Z

When creating a unionfs mount, it's fairly easy to shoot oneself in the foot by specifying upper and lower file hierarchies that resolve back to the same vnodes. This is fairly easy to do if the sameness is not obvious due to aliasing through nullfs or other unionfs mounts (as in the associated PR), and will produce either deadlock or failed locking assertions on any attempt to use the resulting unionfs mount. Leverage VOP_GETLOWVNODE() to detect the most common cases of foot-shooting at mount time and fail the mount with EDEADLK. This is not meant to be an exhaustive check for all possible deadlock-producing scenarios, but it is an extremely cheap and simple approach that, unlike previous proposed fixes, also works in the presence of nullfs aliases. PR: 172334 Reported by: ngie, Karlo Miličević Reviewed by: kib, olce Tested by: pho MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D53988

unionfs: Implement VOP_GETLOWVNODE

2025-12-12T06:32:05Z

This function returns the vnode that will be used to resolve the access type specified in the 'flags' argument, and is useful for optimal behavior of vn_copy_file_range(). While most filesystems can simply use the default implementation which returns the passed- in vnode, unionfs (like nullfs) ideally should resolve the access request to whichever base layer vnode will be used for the I/O. For unionfs, write accesses must be resolved through the upper vnode, while read accesses will be resolved through the upper vnode if present or the lower vnode otherwise. Provide a simple unionfs_getlowvnode() implementation that reflects this policy. Reviewed by: kib, olce Tested by: pho MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D53988

unionfs: avoid vdrop()ing a locked but doomed vnode

2025-10-16T15:30:34Z

unionfs_lock() unconditionally calls vdrop() on the target vnode after locking it, but it's possible this vnode may be doomed. In that case, vdrop() may free the vnode, which in certain cases requires taking the vnode lock. Commit a7aac8c20497d added an assert to this effect, which unionfs_lock() now trips over. Fix this by lightly reworking the flow of unionfs_lock() so that the target vnode is vdrop()ed after being unlocked in the case where the unionfs lock operation needs to be restarted (which will happen if the unionfs vnode has been doomed, which is a prerequisite for the target vnode in the underlying filesystem to have been doomed). While here, get rid of a superfluous vhold/vdrop sequence in unionfs_unlock() that was probably inherited from nullfs and whose nullfs equivalent was recently removed. MFC after: 1 week Reviewed by: kib, markj, olce Tested by: pho Differential Revision: https://reviews.freebsd.org/D53107

unionfs: fix NULL deref on closing an fd passed through SCM_RIGHTS

2025-10-14T18:48:51Z

If the last reference to an open file is contained in an SCM_RIGHTS message in a UNIX domain socket, and that message is discarded without being read out by the receiver, VOP_CLOSE will ultimately be called with ap->a_td == NULL. Change unionfs_close() to check for this condition instead of blindly passing the thread to unionfs_find_node_status() which will try to dereference it. Also add relevant asserts on the node status lookup paths. PR: 289700 Reported by: asomers Reviewed by: asomers, olce MFC after: 3 days Differential Revision: https://reviews.freebsd.org/D53079

vfs: retire the NULLVP macro

2025-09-27T04:00:59Z

The kernel was already mostly using plain NULL, just whack it and be doen with the legacy. Churn generated with coccinelle: @@ @@ - NULLVP + NULL

namei: Fix cn_flags width in various places

2025-05-27T13:29:14Z

This truncation is mostly harmless today, but fix it anyway to avoid pain later down the road. Reviewed by: olce, kib MFC after: 2 weeks Differential Revision: https://reviews.freebsd.org/D50417