From 1602bad16d7df82faca6d7c70821117684a66f49 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Tue, 11 Nov 2025 09:12:58 -0500 Subject: vfs: expose delegation support to userland Now that support for recallable directory delegations is available, expose this functionality to userland with new F_SETDELEG and F_GETDELEG commands for fcntl(). Note that this also allows userland to request a FL_DELEG type lease on files too. Userland applications that do will get signalled when there are metadata changes in addition to just data changes (which is a limitation of FL_LEASE leases). These commands accept a new "struct delegation" argument that contains a flags field for future expansion. Signed-off-by: Jeff Layton Link: https://patch.msgid.link/20251111-dir-deleg-ro-v6-17-52f3feebb2f2@kernel.org Reviewed-by: Jan Kara Signed-off-by: Christian Brauner --- include/uapi/linux/fcntl.h | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'include/uapi') diff --git a/include/uapi/linux/fcntl.h b/include/uapi/linux/fcntl.h index 3741ea1b73d8..008fac15e573 100644 --- a/include/uapi/linux/fcntl.h +++ b/include/uapi/linux/fcntl.h @@ -79,6 +79,17 @@ */ #define RWF_WRITE_LIFE_NOT_SET RWH_WRITE_LIFE_NOT_SET +/* Set/Get delegations */ +#define F_GETDELEG (F_LINUX_SPECIFIC_BASE + 15) +#define F_SETDELEG (F_LINUX_SPECIFIC_BASE + 16) + +/* Argument structure for F_GETDELEG and F_SETDELEG */ +struct delegation { + uint32_t d_flags; /* Must be 0 */ + uint16_t d_type; /* F_RDLCK, F_WRLCK, F_UNLCK */ + uint16_t __pad; /* Must be 0 */ +}; + /* * Types of directory notifications that may be requested. */ -- cgit v1.2.3