linux/fs/nfsd
Jeff Layton cd123012d9 RPC: add wrapper for svc_reserve to account for checksum
When the kernel calls svc_reserve to downsize the expected size of an RPC
reply, it fails to account for the possibility of a checksum at the end of
the packet.  If a client mounts a NFSv2/3 with sec=krb5i/p, and does I/O
then you'll generally see messages similar to this in the server's ring
buffer:

RPC request reserved 164 but used 208

While I was never able to verify it, I suspect that this problem is also
the root cause of some oopses I've seen under these conditions:

https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=227726

This is probably also a problem for other sec= types and for NFSv4.  The
large reserved size for NFSv4 compound packets seems to generally paper
over the problem, however.

This patch adds a wrapper for svc_reserve that accounts for the possibility
of a checksum.  It also fixes up the appropriate callers of svc_reserve to
call the wrapper.  For now, it just uses a hardcoded value that I
determined via testing.  That value may need to be revised upward as things
change, or we may want to eventually add a new auth_op that attempts to
calculate this somehow.

Unfortunately, there doesn't seem to be a good way to reliably determine
the expected checksum length prior to actually calculating it, particularly
with schemes like spkm3.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Neil Brown <neilb@suse.de>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Acked-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-09 12:30:54 -07:00
..
auth.c [PATCH] knfsd: nfsd: nfsd_setuser doesn't really need to modify rqstp->rq_cred. 2006-04-11 06:18:52 -07:00
export.c [PATCH] remove many unneeded #includes of sched.h 2007-02-14 08:09:54 -08:00
lockd.c [PATCH] lockd endianness annotations 2006-12-13 09:05:52 -08:00
Makefile [PATCH] knfsd: nfsd4: reboot hash 2005-06-24 00:06:33 -07:00
nfs2acl.c [PATCH] Fix a free-wrong-pointer bug in nfs/acl server. 2007-02-19 16:13:28 -08:00
nfs3acl.c [PATCH] NFS3: Calculate 'w' a bit later in nfs3svc_encode_getaclres() 2006-12-08 08:29:02 -08:00
nfs3proc.c RPC: add wrapper for svc_reserve to account for checksum 2007-05-09 12:30:54 -07:00
nfs3xdr.c The NFSv2/NFSv3 server does not handle zero length WRITE requests correctly 2007-05-09 12:30:54 -07:00
nfs4acl.c remove nfs4_acl_add_ace() 2007-05-09 12:30:54 -07:00
nfs4callback.c SUNRPC: RPC buffer size estimates are too large 2007-04-30 22:17:10 -07:00
nfs4idmap.c header cleaning: don't include smp_lock.h when not used 2007-05-08 11:15:07 -07:00
nfs4proc.c [PATCH] knfsd: nfsd4: simplify filehandle check 2006-12-13 09:05:54 -08:00
nfs4recover.c [PATCH] lockdep: annotate nfsd4 recover code 2006-12-08 08:29:01 -08:00
nfs4state.c nfsd/nfs4state: remove unnecessary daemonize call 2007-05-09 12:30:54 -07:00
nfs4xdr.c header cleaning: don't include smp_lock.h when not used 2007-05-08 11:15:07 -07:00
nfscache.c [PATCH] knfsd: SUNRPC: Provide room in svc_rqst for larger addresses 2007-02-12 09:48:36 -08:00
nfsctl.c [PATCH] knfsd: fix return value for writes to some files in 'nfsd' filesystem 2007-02-14 08:09:53 -08:00
nfsfh.c header cleaning: don't include smp_lock.h when not used 2007-05-08 11:15:07 -07:00
nfsproc.c RPC: add wrapper for svc_reserve to account for checksum 2007-05-09 12:30:54 -07:00
nfssvc.c [PATCH] knfsd: SUNRPC: allow creating an RPC service without registering with portmapper 2007-02-12 09:48:35 -08:00
nfsxdr.c The NFSv2/NFSv3 server does not handle zero length WRITE requests correctly 2007-05-09 12:30:54 -07:00
stats.c [PATCH] knfsd: nfsd4: add per-operation server stats 2006-07-10 13:24:27 -07:00
vfs.c [PATCH] knfsd: nfsd4: fix error return on unsupported acl 2007-02-16 08:14:01 -08:00