svn commit: r336041 - head/sys/fs/nfsserver

[Rick Macklem]

Author: rmacklem
Date: Fri Jul  6 19:18:45 2018
New Revision: 336041
URL: https://svnweb.freebsd.org/changeset/base/336041

Log:
  Change the pNFS server so that it does not disable a mirrored DS for
  an NFSERR_STALE error reported via a LayoutReturn.
  
  The current FreeBSD client can generate these errors for an operational
  DS while doing a recovery of a mirror after a mirrored DS has been repaired.
  I am not sure why these errors occur, but my best current guess is a race
  between the Layout Recall issued by the kernel code run from pnfsdscopymr(8)
  and a Read operation on the DS for the file bing copied.
  The errors are not fatal, since the client falls back on doing I/O through
  the MDS, which can do the I/O successfully as a proxy. (The fact that the
  MDS can do this indicates that the file does still exist on the functioning
  DS.)
  This change only affects the pNFS server and only when a client does a
  LayoutReturn with the NFSERR_STALE error report.

Modified:
  head/sys/fs/nfsserver/nfs_nfsdstate.c

Modified: head/sys/fs/nfsserver/nfs_nfsdstate.c
==============================================================================
--- head/sys/fs/nfsserver/nfs_nfsdstate.c	Fri Jul  6 19:10:11 2018	(r336040)
+++ head/sys/fs/nfsserver/nfs_nfsdstate.c	Fri Jul  6 19:18:45 2018	(r336041)
@@ -6750,9 +6750,10 @@ nfsrv_flexlayouterr(struct nfsrv_descript *nd, uint32_
 			NFSD_DEBUG(4, "flexlayouterr op=%d stat=%d\n", opnum,
 			    stat);
 			/*
-			 * Except for NFSERR_ACCES errors, disable the mirror.
+			 * Except for NFSERR_ACCES and NFSERR_STALE errors,
+			 * disable the mirror.
 			 */
-			if (stat != NFSERR_ACCES)
+			if (stat != NFSERR_ACCES && stat != NFSERR_STALE)
 				nfsrv_delds(devid, p);
 		}
 	}