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A problem w.r.t. interoperation between the FreeBSD NFSv4.1 server with

Browse Source 
delegations enabled and the Linux NFSv4.1 client was reported in
reviews.freebsd.org/D7891.
I believe that the FreeBSD server behaviour conforms to the RFC and that
the Linux client has a bug. Therefore, I do not think the proposed patch
is appropriate. When nfsrv_writedelegifpos is non-zero, the FreeBSD
server will issue a write delegation for a read open if possible.
The Linux client then erroneously assumes that the credentials used for
the read open can write the file.
This patch reverses the default value for nfsrv_writedelegifpos to 0 so
that the default behaviour is Linux compatible and adds a sysctl that can
be used to set nfsrv_writedelegifpos.

This change should only affect users that are mounting a FreeBSD server
with delegations enabled (they are not enabled by default) with a Linux
NFSv4.1 client mount.

Reported by:	fatih.acar@gandi.net
Tested by:	fatih.acar@gandi.net
MFC after:	2 weeks
Differential Revision:	https://reviews.freebsd.org/D7891
This commit is contained in:
rmacklem 2016-10-20 23:53:16 +00:00
parent f9b2499351
commit 9c3c069006
1 changed files with 5 additions and 1 deletions
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6
sys/fs/nfsserver/nfs_nfsdstate.c
View File

@ -70,6 +70,11 @@ SYSCTL_INT(_vfs_nfsd, OID_AUTO, v4statelimit, CTLFLAG_RWTUN,
&nfsrv_v4statelimit, 0,
"High water limit for NFSv4 opens+locks+delegations");
static int nfsrv_writedelegifpos = 0;
SYSCTL_INT(_vfs_nfsd, OID_AUTO, writedelegifpos, CTLFLAG_RW,
&nfsrv_writedelegifpos, 0,
"Issue a write delegation for read opens if possible");
/*
* Hash lists for nfs V4.
*/
@ -80,7 +85,6 @@ struct nfssessionhash *nfssessionhash;
static u_int32_t nfsrv_openpluslock = 0, nfsrv_delegatecnt = 0;
static time_t nfsrvboottime;
static int nfsrv_writedelegifpos = 1;
static int nfsrv_returnoldstateid = 0, nfsrv_clients = 0;
static int nfsrv_clienthighwater = NFSRV_CLIENTHIGHWATER;
static int nfsrv_nogsscallback = 0;