freebsd-dev/sys/nfsclient/nfsargs.h
Brian Feldman cc3149b1ea Fix a serious deadlock with the NFS client. Given a large enough
atomic write request, it can fill the buffer cache with the entirety
of that write in order to handle retries.  However, it never drops
the vnode lock, or else it wouldn't be atomic, so it ends up waiting
indefinitely for more buf memory that cannot be gotten as it has it
all, and it waits in an uncancellable state.

To fix this, hibufspace is exported and scaled to a reasonable
fraction.  This is used as the limit of how much of an atomic write
request by the NFS client will be handled asynchronously.  If the
request is larger than this, it will be turned into a synchronous
request which won't deadlock the system.  It's possible this value is
far off from what is required by some, so it shall be tunable as soon
as mount_nfs(8) learns of the new field.

The slowdown between an asynchronous and a synchronous write on NFS
appears to be on the order of 2x-4x.

General nod by:	gad
MFC after:	2 weeks
More testing:	wes
PR:		kern/79208
2005-06-10 23:50:41 +00:00

98 lines
4.3 KiB
C

/*-
* Copyright (c) 1989, 1993, 1995
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Rick Macklem at The University of Guelph.
*
* 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.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*
* @(#)nfs.h 8.4 (Berkeley) 5/1/95
* $FreeBSD$
*/
#ifndef _NFSCLIENT_NFSARGS_H_
#define _NFSCLIENT_NFSARGS_H_
/*
* Arguments to mount NFS
*/
#define NFS_ARGSVERSION 3 /* change when nfs_args changes */
struct nfs_args {
int version; /* args structure version number */
struct sockaddr *addr; /* file server address */
int addrlen; /* length of address */
int sotype; /* Socket type */
int proto; /* and Protocol */
u_char *fh; /* File handle to be mounted */
int fhsize; /* Size, in bytes, of fh */
int flags; /* flags */
int wsize; /* write size in bytes */
int rsize; /* read size in bytes */
int readdirsize; /* readdir size in bytes */
int timeo; /* initial timeout in .1 secs */
int retrans; /* times to retry send */
int maxgrouplist; /* Max. size of group list */
int readahead; /* # of blocks to readahead */
int wcommitsize; /* Max. write commit size in bytes */
int deadthresh; /* Retrans threshold */
char *hostname; /* server's name */
int acregmin; /* cache attrs for reg files min time */
int acregmax; /* cache attrs for reg files max time */
int acdirmin; /* cache attrs for dirs min time */
int acdirmax; /* cache attrs for dirs max time */
};
/*
* NFS mount option flags
*/
#define NFSMNT_SOFT 0x00000001 /* soft mount (hard is default) */
#define NFSMNT_WSIZE 0x00000002 /* set write size */
#define NFSMNT_RSIZE 0x00000004 /* set read size */
#define NFSMNT_TIMEO 0x00000008 /* set initial timeout */
#define NFSMNT_RETRANS 0x00000010 /* set number of request retries */
#define NFSMNT_MAXGRPS 0x00000020 /* set maximum grouplist size */
#define NFSMNT_INT 0x00000040 /* allow interrupts on hard mount */
#define NFSMNT_NOCONN 0x00000080 /* Don't Connect the socket */
/* 0x100 free, was NFSMNT_NQNFS */
#define NFSMNT_NFSV3 0x00000200 /* Use NFS Version 3 protocol */
/* 0x400 free, was NFSMNT_KERB */
#define NFSMNT_DUMBTIMR 0x00000800 /* Don't estimate rtt dynamically */
#define NFSMNT_WCOMMITSIZE 0x00001000 /* set max write commit size */
#define NFSMNT_READAHEAD 0x00002000 /* set read ahead */
#define NFSMNT_DEADTHRESH 0x00004000 /* set dead server retry thresh */
#define NFSMNT_RESVPORT 0x00008000 /* Allocate a reserved port */
#define NFSMNT_RDIRPLUS 0x00010000 /* Use Readdirplus for V3 */
#define NFSMNT_READDIRSIZE 0x00020000 /* Set readdir size */
#define NFSMNT_ACREGMIN 0x00040000
#define NFSMNT_ACREGMAX 0x00080000
#define NFSMNT_ACDIRMIN 0x00100000
#define NFSMNT_ACDIRMAX 0x00200000
#define NFSMNT_NOLOCKD 0x00400000 /* Locks are local */
#define NFSMNT_NFSV4 0x00800000 /* Use NFS Version 4 protocol */
#define NFSMNT_HASWRITEVERF 0x01000000 /* NFSv4 Write verifier */
#endif