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433f9d76a0
Add ability to set per-dentry mount expire timeout to autofs. There are two fairly well known automounter map formats, the autofs format and the amd format (more or less System V and Berkley). Some time ago Linux autofs added an amd map format parser that implemented a fair amount of the amd functionality. This was done within the autofs infrastructure and some functionality wasn't implemented because it either didn't make sense or required extra kernel changes. The idea was to restrict changes to be within the existing autofs functionality as much as possible and leave changes with a wider scope to be considered later. One of these changes is implementing the amd options: 1) "unmount", expire this mount according to a timeout (same as the current autofs default). 2) "nounmount", don't expire this mount (same as setting the autofs timeout to 0 except only for this specific mount) . 3) "utimeout=<seconds>", expire this mount using the specified timeout (again same as setting the autofs timeout but only for this mount). To implement these options per-dentry expire timeouts need to be implemented for autofs indirect mounts. This is because all map keys (mounts) for autofs indirect mounts use an expire timeout stored in the autofs mount super block info. structure and all indirect mounts use the same expire timeout. Now I have a request to add the "nounmount" option so I need to add the per-dentry expire handling to the kernel implementation to do this. The implementation uses the trailing path component to identify the mount (and is also used as the autofs map key) which is passed in the autofs_dev_ioctl structure path field. The expire timeout is passed in autofs_dev_ioctl timeout field (well, of the timeout union). If the passed in timeout is equal to -1 the per-dentry timeout and flag are cleared providing for the "unmount" option. If the timeout is greater than or equal to 0 the timeout is set to the value and the flag is also set. If the dentry timeout is 0 the dentry will not expire by timeout which enables the implementation of the "nounmount" option for the specific mount. When the dentry timeout is greater than zero it allows for the implementation of the "utimeout=<seconds>" option. Signed-off-by: Ian Kent <raven@themaw.net> Link: https://lore.kernel.org/r/20240814090231.963520-1-raven@themaw.net Signed-off-by: Christian Brauner <brauner@kernel.org>
232 lines
6.3 KiB
C
232 lines
6.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
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/*
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* Copyright 1997 Transmeta Corporation - All Rights Reserved
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* Copyright 1999-2000 Jeremy Fitzhardinge <jeremy@goop.org>
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* Copyright 2005-2006,2013,2017-2018 Ian Kent <raven@themaw.net>
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*
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* This file is part of the Linux kernel and is made available under
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* the terms of the GNU General Public License, version 2, or at your
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* option, any later version, incorporated herein by reference.
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*
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* ----------------------------------------------------------------------- */
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#ifndef _UAPI_LINUX_AUTO_FS_H
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#define _UAPI_LINUX_AUTO_FS_H
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#include <linux/types.h>
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#include <linux/limits.h>
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#ifndef __KERNEL__
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#include <sys/ioctl.h>
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#endif /* __KERNEL__ */
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#define AUTOFS_PROTO_VERSION 5
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#define AUTOFS_MIN_PROTO_VERSION 3
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#define AUTOFS_MAX_PROTO_VERSION 5
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#define AUTOFS_PROTO_SUBVERSION 6
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/*
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* The wait_queue_token (autofs_wqt_t) is part of a structure which is passed
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* back to the kernel via ioctl from userspace. On architectures where 32- and
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* 64-bit userspace binaries can be executed it's important that the size of
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* autofs_wqt_t stays constant between 32- and 64-bit Linux kernels so that we
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* do not break the binary ABI interface by changing the structure size.
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*/
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#if defined(__ia64__) || defined(__alpha__) /* pure 64bit architectures */
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typedef unsigned long autofs_wqt_t;
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#else
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typedef unsigned int autofs_wqt_t;
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#endif
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/* Packet types */
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#define autofs_ptype_missing 0 /* Missing entry (mount request) */
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#define autofs_ptype_expire 1 /* Expire entry (umount request) */
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struct autofs_packet_hdr {
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int proto_version; /* Protocol version */
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int type; /* Type of packet */
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};
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struct autofs_packet_missing {
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struct autofs_packet_hdr hdr;
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autofs_wqt_t wait_queue_token;
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int len;
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char name[NAME_MAX+1];
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};
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/* v3 expire (via ioctl) */
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struct autofs_packet_expire {
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struct autofs_packet_hdr hdr;
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int len;
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char name[NAME_MAX+1];
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};
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#define AUTOFS_IOCTL 0x93
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enum {
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AUTOFS_IOC_READY_CMD = 0x60,
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AUTOFS_IOC_FAIL_CMD,
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AUTOFS_IOC_CATATONIC_CMD,
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AUTOFS_IOC_PROTOVER_CMD,
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AUTOFS_IOC_SETTIMEOUT_CMD,
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AUTOFS_IOC_EXPIRE_CMD,
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};
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#define AUTOFS_IOC_READY _IO(AUTOFS_IOCTL, AUTOFS_IOC_READY_CMD)
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#define AUTOFS_IOC_FAIL _IO(AUTOFS_IOCTL, AUTOFS_IOC_FAIL_CMD)
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#define AUTOFS_IOC_CATATONIC _IO(AUTOFS_IOCTL, AUTOFS_IOC_CATATONIC_CMD)
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#define AUTOFS_IOC_PROTOVER _IOR(AUTOFS_IOCTL, \
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AUTOFS_IOC_PROTOVER_CMD, int)
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#define AUTOFS_IOC_SETTIMEOUT32 _IOWR(AUTOFS_IOCTL, \
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AUTOFS_IOC_SETTIMEOUT_CMD, \
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compat_ulong_t)
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#define AUTOFS_IOC_SETTIMEOUT _IOWR(AUTOFS_IOCTL, \
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AUTOFS_IOC_SETTIMEOUT_CMD, \
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unsigned long)
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#define AUTOFS_IOC_EXPIRE _IOR(AUTOFS_IOCTL, \
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AUTOFS_IOC_EXPIRE_CMD, \
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struct autofs_packet_expire)
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/* autofs version 4 and later definitions */
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/* Mask for expire behaviour */
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#define AUTOFS_EXP_NORMAL 0x00
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#define AUTOFS_EXP_IMMEDIATE 0x01
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#define AUTOFS_EXP_LEAVES 0x02
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#define AUTOFS_EXP_FORCED 0x04
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#define AUTOFS_TYPE_ANY 0U
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#define AUTOFS_TYPE_INDIRECT 1U
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#define AUTOFS_TYPE_DIRECT 2U
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#define AUTOFS_TYPE_OFFSET 4U
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static inline void set_autofs_type_indirect(unsigned int *type)
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{
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*type = AUTOFS_TYPE_INDIRECT;
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}
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static inline unsigned int autofs_type_indirect(unsigned int type)
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{
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return (type == AUTOFS_TYPE_INDIRECT);
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}
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static inline void set_autofs_type_direct(unsigned int *type)
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{
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*type = AUTOFS_TYPE_DIRECT;
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}
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static inline unsigned int autofs_type_direct(unsigned int type)
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{
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return (type == AUTOFS_TYPE_DIRECT);
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}
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static inline void set_autofs_type_offset(unsigned int *type)
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{
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*type = AUTOFS_TYPE_OFFSET;
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}
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static inline unsigned int autofs_type_offset(unsigned int type)
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{
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return (type == AUTOFS_TYPE_OFFSET);
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}
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static inline unsigned int autofs_type_trigger(unsigned int type)
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{
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return (type == AUTOFS_TYPE_DIRECT || type == AUTOFS_TYPE_OFFSET);
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}
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/*
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* This isn't really a type as we use it to say "no type set" to
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* indicate we want to search for "any" mount in the
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* autofs_dev_ioctl_ismountpoint() device ioctl function.
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*/
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static inline void set_autofs_type_any(unsigned int *type)
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{
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*type = AUTOFS_TYPE_ANY;
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}
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static inline unsigned int autofs_type_any(unsigned int type)
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{
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return (type == AUTOFS_TYPE_ANY);
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}
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/* Daemon notification packet types */
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enum autofs_notify {
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NFY_NONE,
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NFY_MOUNT,
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NFY_EXPIRE
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};
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/* Kernel protocol version 4 packet types */
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/* Expire entry (umount request) */
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#define autofs_ptype_expire_multi 2
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/* Kernel protocol version 5 packet types */
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/* Indirect mount missing and expire requests. */
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#define autofs_ptype_missing_indirect 3
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#define autofs_ptype_expire_indirect 4
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/* Direct mount missing and expire requests */
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#define autofs_ptype_missing_direct 5
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#define autofs_ptype_expire_direct 6
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/* v4 multi expire (via pipe) */
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struct autofs_packet_expire_multi {
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struct autofs_packet_hdr hdr;
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autofs_wqt_t wait_queue_token;
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int len;
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char name[NAME_MAX+1];
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};
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union autofs_packet_union {
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struct autofs_packet_hdr hdr;
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struct autofs_packet_missing missing;
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struct autofs_packet_expire expire;
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struct autofs_packet_expire_multi expire_multi;
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};
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/* autofs v5 common packet struct */
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struct autofs_v5_packet {
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struct autofs_packet_hdr hdr;
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autofs_wqt_t wait_queue_token;
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__u32 dev;
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__u64 ino;
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__u32 uid;
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__u32 gid;
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__u32 pid;
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__u32 tgid;
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__u32 len;
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char name[NAME_MAX+1];
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};
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typedef struct autofs_v5_packet autofs_packet_missing_indirect_t;
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typedef struct autofs_v5_packet autofs_packet_expire_indirect_t;
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typedef struct autofs_v5_packet autofs_packet_missing_direct_t;
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typedef struct autofs_v5_packet autofs_packet_expire_direct_t;
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union autofs_v5_packet_union {
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struct autofs_packet_hdr hdr;
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struct autofs_v5_packet v5_packet;
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autofs_packet_missing_indirect_t missing_indirect;
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autofs_packet_expire_indirect_t expire_indirect;
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autofs_packet_missing_direct_t missing_direct;
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autofs_packet_expire_direct_t expire_direct;
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};
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enum {
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AUTOFS_IOC_EXPIRE_MULTI_CMD = 0x66, /* AUTOFS_IOC_EXPIRE_CMD + 1 */
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AUTOFS_IOC_PROTOSUBVER_CMD,
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AUTOFS_IOC_ASKUMOUNT_CMD = 0x70, /* AUTOFS_DEV_IOCTL_VERSION_CMD - 1 */
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};
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#define AUTOFS_IOC_EXPIRE_MULTI _IOW(AUTOFS_IOCTL, \
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AUTOFS_IOC_EXPIRE_MULTI_CMD, int)
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#define AUTOFS_IOC_PROTOSUBVER _IOR(AUTOFS_IOCTL, \
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AUTOFS_IOC_PROTOSUBVER_CMD, int)
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#define AUTOFS_IOC_ASKUMOUNT _IOR(AUTOFS_IOCTL, \
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AUTOFS_IOC_ASKUMOUNT_CMD, int)
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#endif /* _UAPI_LINUX_AUTO_FS_H */
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