NFSv4.1: pNFS data servers may be temporarily offline

In cases where the pNFS data server is just temporarily out of service,
we want to mark it as such, and then try again later. Typically that will
be in cases of network connection errors etc.
This patch allows us to mark the devices as being "unavailable" for such
transient errors, and will make them available for retries after a
2 minute timeout period.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
index bc8e5001203d..9735031e1e1a 100644
--- a/fs/nfs/pnfs.h
+++ b/fs/nfs/pnfs.h
@@ -234,6 +234,7 @@ struct nfs4_threshold *pnfs_mdsthreshold_alloc(void);
 /* nfs4_deviceid_flags */
 enum {
         NFS_DEVICEID_INVALID = 0,       /* set when MDS clientid recalled */
+        NFS_DEVICEID_UNAVAILABLE,       /* device temporarily unavailable */
 };
 
 /* pnfs_dev.c */
@@ -243,6 +244,7 @@ struct nfs4_deviceid_node {
         const struct pnfs_layoutdriver_type *ld;
         const struct nfs_client         *nfs_client;
         unsigned long                   flags;
+        unsigned long                   timestamp_unavailable;
         struct nfs4_deviceid            deviceid;
         atomic_t                        ref;
 };
@@ -255,6 +257,8 @@ void nfs4_init_deviceid_node(struct nfs4_deviceid_node *,
                              const struct nfs4_deviceid *);
 struct nfs4_deviceid_node *nfs4_insert_deviceid_node(struct nfs4_deviceid_node *);
 bool nfs4_put_deviceid_node(struct nfs4_deviceid_node *);
+void nfs4_mark_deviceid_unavailable(struct nfs4_deviceid_node *node);
+bool nfs4_test_deviceid_unavailable(struct nfs4_deviceid_node *node);
 void nfs4_deviceid_purge_client(const struct nfs_client *);
 
 static inline void