[PATCH/RFC 7/7] Added error handling for NFS4ERR_FHEXPIRED

[Matthew Treinish <treinish@linux.vnet.ibm.com>]

Added checks in the nfs4_handle_exception for FHEXPIRED.
If FHEXPIRED is received from the server and the appropriate
attributes are enabled then the client calls
nfs4_fhexpired_recovery() to perform the lookup operation to
try and recovery the expired vfh.

If the mount option is not enabled or the server FH_EXPIRE_TYPE
doesn't have VOLATILE_ANY then client will convert the
FHEXPIRED error into ESTALE since recovery isn't possible.

Signed-off-by: Matthew Treinish <treinish@linux.vnet.ibm.com>
---
 fs/nfs/nfs4proc.c |   10 ++++++++++
 1 files changed, 10 insertions(+), 0 deletions(-)

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index ebc5ee9..8ae5c49 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -277,6 +277,16 @@ static int nfs4_handle_exception(struct nfs_server *server, int errorcode, struc
 		case -NFS4ERR_STALE_CLIENTID:
 			nfs4_schedule_lease_recovery(clp);
 			goto wait_on_recovery;
+		case -NFS4ERR_FHEXPIRED:
+			if (server->flags & NFS_MOUNT_VFHRETRY)
+				if (server->fhexpiretype & NFS4_FH_VOLATILE_ANY) {
+					ret = nfs4_fhexpired_recovery(server, exception);
+					if (!ret)
+						ret = -EAGAIN;
+					break;
+				}
+			ret = -ESTALE;
+			break;
 #if defined(CONFIG_NFS_V4_1)
 		case -NFS4ERR_BADSESSION:
 		case -NFS4ERR_BADSLOT:
-- 
1.7.4.4