Author: rmacklem
Date: Fri Jun 22 21:37:20 2018
New Revision: 335568
URL: https://svnweb.freebsd.org/changeset/base/335568
Log:
Fix the handling of NFSv4.1 sessions for "soft" mounts.
When a "soft" mount is used for NFSv4.1, an RPC that fails without completing
will leave a slot in the NFSv4.1 session in an indeterminate state.
As such, all that can be done is free up the slot while making is no longer
usable.
A "soft" NFSv4.1 mount is not recommended in general, since it will leave
Open/Lock state in an indeterminate state. An exception is a pNFS mount of
a DS, since there are no Opens/Locks done for them except file creates
where loss of the Open state does not matter.
The patch also makes connections to DSs soft, so that they will fail when
a DS is non-functional or network partitioned, allowing the pNFS MDS to
disable
the DS for a mirrored configuration.
This patch should not affect normal "hard" NFSv4.1 mounts.
MFC after: 2 weeks
Modified:
head/sys/fs/nfs/nfs_commonkrpc.c
Modified: head/sys/fs/nfs/nfs_commonkrpc.c
==============================================================================
--- head/sys/fs/nfs/nfs_commonkrpc.c Fri Jun 22 21:25:27 2018
(r335567)
+++ head/sys/fs/nfs/nfs_commonkrpc.c Fri Jun 22 21:37:20 2018
(r335568)
@@ -157,6 +157,9 @@ static int nfsv2_procid[NFS_V3NPROCS] = {
/*
* Initialize sockets and congestion for a new NFS connection.
* We do not free the sockaddr if error.
+ * Which arguments are set to NULL indicate what kind of call it is.
+ * cred == NULL --> a call to connect to a pNFS DS
+ * nmp == NULL --> indicates an upcall to userland or a NFSv4.0 callback
*/
int
newnfs_connect(struct nfsmount *nmp, struct nfssockreq *nrp,
@@ -293,24 +296,38 @@ newnfs_connect(struct nfsmount *nmp, struct nfssockreq
retries = nmp->nm_retry;
} else
retries = INT_MAX;
- /* cred == NULL for DS connects. */
- if (NFSHASNFSV4N(nmp) && cred != NULL) {
- /*
- * Make sure the nfscbd_pool doesn't get destroyed
- * while doing this.
- */
- NFSD_LOCK();
- if (nfs_numnfscbd > 0) {
- nfs_numnfscbd++;
- NFSD_UNLOCK();
- xprt = svc_vc_create_backchannel(nfscbd_pool);
- CLNT_CONTROL(client, CLSET_BACKCHANNEL, xprt);
+ if (NFSHASNFSV4N(nmp)) {
+ if (cred != NULL) {
+ /*
+ * Make sure the nfscbd_pool doesn't get
+ * destroyed while doing this.
+ */
NFSD_LOCK();
- nfs_numnfscbd--;
- if (nfs_numnfscbd == 0)
- wakeup(&nfs_numnfscbd);
+ if (nfs_numnfscbd > 0) {
+ nfs_numnfscbd++;
+ NFSD_UNLOCK();
+ xprt = svc_vc_create_backchannel(
+ nfscbd_pool);
+ CLNT_CONTROL(client, CLSET_BACKCHANNEL,
+ xprt);
+ NFSD_LOCK();
+ nfs_numnfscbd--;
+ if (nfs_numnfscbd == 0)
+ wakeup(&nfs_numnfscbd);
+ }
+ NFSD_UNLOCK();
+ } else {
+ /*
+ * cred == NULL for a DS connect.
+ * For connects to a DS, set a retry limit
+ * so that failed DSs will be detected.
+ * This is ok for NFSv4.1, since a DS does
+ * not maintain open/lock state and is the
+ * only case where using a "soft" mount is
+ * recommended for NFSv4.
+ */
+ retries = 2;
}
- NFSD_UNLOCK();
}
} else {
/*
@@ -762,6 +779,7 @@ tryagain:
else
stat = CLNT_CALL_MBUF(nrp->nr_client, &ext, procnum,
nd->nd_mreq, &nd->nd_mrep, timo);
+ NFSCL_DEBUG(2, "clnt call=%d\n", stat);
if (rep != NULL) {
/*
@@ -789,6 +807,36 @@ tryagain:
error = EPROTONOSUPPORT;
} else if (stat == RPC_INTR) {
error = EINTR;
+ } else if (stat == RPC_CANTSEND || stat == RPC_CANTRECV ||
+ stat == RPC_SYSTEMERROR) {
+ /* Check for a session slot that needs to be free'd. */
+ if ((nd->nd_flag & (ND_NFSV41 | ND_HASSLOTID)) ==
+ (ND_NFSV41 | ND_HASSLOTID) && nmp != NULL &&
+ nd->nd_procnum != NFSPROC_NULL) {
+ /*
+ * This should only occur when either the MDS or
+ * a client has an RPC against a DS fail.
+ * This happens because these cases use "soft"
+ * connections that can time out and fail.
+ * The slot used for this RPC is now in a
+ * non-deterministic state, but if the slot isn't
+ * free'd, threads can get stuck waiting for a slot.
+ */
+ if (sep == NULL)
+ sep = nfsmnt_mdssession(nmp);
+ /*
+ * Bump the sequence# out of range, so that reuse of
+ * this slot will result in an NFSERR_SEQMISORDERED
+ * error and not a bogus cached RPC reply.
+ */
+ mtx_lock(&sep->nfsess_mtx);
+ sep->nfsess_slotseq[nd->nd_slotid] += 10;
+ mtx_unlock(&sep->nfsess_mtx);
+ /* And free the slot. */
+ nfsv4_freeslot(sep, nd->nd_slotid);
+ }
+ NFSINCRGLOBAL(nfsstatsv1.rpcinvalid);
+ error = ENXIO;
} else {
NFSINCRGLOBAL(nfsstatsv1.rpcinvalid);
error = EACCES;
_______________________________________________
svn-src-all@freebsd.org mailing list
https://lists.freebsd.org/mailman/listinfo/svn-src-all
To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
