git: fc0dc94029df - main - nfsd: Reduce the callback timeout to 800msec

[Rick Macklem]

The branch main has been updated by rmacklem:

URL: https://cgit.FreeBSD.org/src/commit/?id=fc0dc94029df8150301b925bda690b20d9d0bcbf

commit fc0dc94029df8150301b925bda690b20d9d0bcbf
Author:     Rick Macklem <rmacklem at FreeBSD.org>
AuthorDate: 2021-05-18 23:17:58 +0000
Commit:     Rick Macklem <rmacklem at FreeBSD.org>
CommitDate: 2021-05-18 23:17:58 +0000

    nfsd: Reduce the callback timeout to 800msec
    
    Recent discussion on the nfsv4 at ietf.org mailing list confirmed
    that an NFSv4 server should reply to an RPC in less than 1second.
    If an NFSv4 RPC requires a delegation be recalled,
    the server will attempt a CB_RECALL callback.
    If the client is not responsive, the RPC reply will be delayed
    until the callback times out.
    Without this patch, the timeout is set to 4 seconds (set in
    ticks, but used as seconds), resulting in the RPC reply taking over 4sec.
    This patch redefines the constant as being in milliseconds and it
    implements that for a value of 800msec, to ensure the RPC
    reply is sent in less than 1second.
    
    This patch only affects mounts from clients when delegations
    are enabled on the server and the client is unresponsive to callbacks.
    
    MFC after:      2 weeks
---
 sys/fs/nfs/nfs.h            |  2 +-
 sys/fs/nfs/nfs_commonkrpc.c | 10 ++++++----
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/sys/fs/nfs/nfs.h b/sys/fs/nfs/nfs.h
index 44b6042a2ce7..272b8dbfee22 100644
--- a/sys/fs/nfs/nfs.h
+++ b/sys/fs/nfs/nfs.h
@@ -50,7 +50,7 @@
 #define	NFS_MAXRCVTIMEO	60		/* 1 minute in seconds */
 #define	NFS_MINIDEMTIMEO (5 * NFS_HZ)	/* Min timeout for non-idempotent ops*/
 #define	NFS_MAXREXMIT	100		/* Stop counting after this many */
-#define	NFSV4_CALLBACKTIMEO (2 * NFS_HZ) /* Timeout in ticks */
+#define	NFSV4_CALLBACKTIMEO 800		/* Timeout in msec */
 #define	NFSV4_CALLBACKRETRY 5		/* Number of retries before failure */
 #define	NFSV4_SLOTS	64		/* Number of slots, fore channel */
 #define	NFSV4_CBSLOTS	8		/* Number of slots, back channel */
diff --git a/sys/fs/nfs/nfs_commonkrpc.c b/sys/fs/nfs/nfs_commonkrpc.c
index 49c68da45a69..04ef04955ce0 100644
--- a/sys/fs/nfs/nfs_commonkrpc.c
+++ b/sys/fs/nfs/nfs_commonkrpc.c
@@ -767,11 +767,13 @@ tryagain:
 	 * use the same xid.
 	 */
 	if (nmp == NULL) {
-		timo.tv_usec = 0;
-		if (clp == NULL)
+		if (clp == NULL) {
 			timo.tv_sec = NFSV4_UPCALLTIMEO;
-		else
-			timo.tv_sec = NFSV4_CALLBACKTIMEO;
+			timo.tv_usec = 0;
+		} else {
+			timo.tv_sec = NFSV4_CALLBACKTIMEO / 1000;
+			timo.tv_usec = NFSV4_CALLBACKTIMEO * 1000;
+		}
 	} else {
 		if (nrp->nr_sotype != SOCK_DGRAM) {
 			timo.tv_usec = 0;