I wanted to reach out to the Samba and Ganesha development communities to advertise that we're adding support for new F_SETDELEG and F_GETDELEG fcntl() commands in Linux v6.19: https://lore.kernel.org/linux-nfs/20251111-dir-deleg-ro-v6-0-52f3feebb2f2@ke... They work like leases, but are broken in more situations, to conform to the needs of NFSv4 delegations. For files, these should expose the correct semantics for NFSv4 delegation support: namely that they are also broken if the dentry is renamed or unlinked. You can now take out a delegation on a directory, and it will be broken when a dentry is added, deleted or renamed within the directory. My main impetus for adding this interface was so that this stuff could more easily be tested, but it did occur to me that this facility might be useful for the existing users of F_SETLEASE. The manpage patch is here: https://lore.kernel.org/linux-man/20260114-master-v2-1-719f5b47dfe2@kernel.o... Please do reach out if you have questions! -- Jeff Layton <jlayton@kernel.org>