freebsd-skq/sys/fs/nfs/nfscl.h
rmacklem 396df4f3c4 Add kernel support for the NFS client forced dismount "umount -N" option.
When an NFS mount is hung against an unresponsive NFS server, the "umount -f"
option can be used to dismount the mount. Unfortunately, "umount -f" gets
hung as well if a "umount" without "-f" has already been done. Usually,
this is because of a vnode lock being held by the "umount" for the mounted-on
vnode.
This patch adds kernel code so that a new "-N" option can be added to "umount",
allowing it to avoid getting hung for this case.
It adds two flags. One indicates that a forced dismount is about to happen
and the other is used, along with setting mnt_data == NULL, to handshake
with the nfs_unmount() VFS call.
It includes a slight change to the interface used between the client and
common NFS modules, so I bumped __FreeBSD_version to ensure both modules are
rebuilt.

Tested by:	pho
Reviewed by:	kib
MFC after:	2 weeks
Differential Revision:	https://reviews.freebsd.org/D11735
2017-07-29 19:52:47 +00:00

82 lines
2.9 KiB
C

/*-
* Copyright (c) 2009 Rick Macklem, University of Guelph
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef _NFS_NFSCL_H
#define _NFS_NFSCL_H
/*
* Extra stuff for a NFSv4 nfsnode.
* MALLOC'd to the correct length for the name and file handle.
* n4_data has the file handle, followed by the file name.
* The macro NFS4NODENAME() returns a pointer to the start of the
* name.
*/
struct nfsv4node {
u_int16_t n4_fhlen;
u_int16_t n4_namelen;
u_int8_t n4_data[1];
};
#define NFS4NODENAME(n) (&((n)->n4_data[(n)->n4_fhlen]))
/*
* Just a macro to convert the nfscl_reqstart arguments.
*/
#define NFSCL_REQSTART(n, p, v) \
nfscl_reqstart((n), (p), VFSTONFS((v)->v_mount), \
VTONFS(v)->n_fhp->nfh_fh, VTONFS(v)->n_fhp->nfh_len, NULL, NULL)
/*
* These two macros convert between a lease duration and renew interval.
* For now, just make the renew interval 1/2 the lease duration.
* (They should be inverse operators.)
*/
#define NFSCL_RENEW(l) (((l) < 2) ? 1 : ((l) / 2))
#define NFSCL_LEASE(r) ((r) * 2)
/* This macro checks to see if a forced dismount is about to occur. */
#define NFSCL_FORCEDISM(m) (((m)->mnt_kern_flag & MNTK_UNMOUNTF) != 0 || \
(VFSTONFS(m)->nm_privflag & NFSMNTP_FORCEDISM) != 0)
/*
* These flag bits are used for the argument to nfscl_fillsattr() to
* indicate special handling of the attributes.
*/
#define NFSSATTR_FULL 0x1
#define NFSSATTR_SIZE0 0x2
#define NFSSATTR_SIZENEG1 0x4
#define NFSSATTR_SIZERDEV 0x8
/* Use this macro for debug printfs. */
#define NFSCL_DEBUG(level, ...) do { \
if (nfscl_debuglevel >= (level)) \
printf(__VA_ARGS__); \
} while (0)
#endif /* _NFS_NFSCL_H */