NFS add session back channel draining

Currently session draining only drains the fore channel.
The back channel processing must also be drained.

Use the back channel highest_slot_used to indicate that a callback is being
processed by the callback thread.  Move the session complete to be per channel.

When the session is draininig, wait for any current back channel processing
to complete and stop all new back channel processing by returning NFS4ERR_DELAY
to the back channel client.

Drain the back channel, then the fore channel.

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

1 files changed, 1 insertions, 1 deletions

diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
index 1eaa054a2c7d..e93ada0565fc 100644
--- a/include/linux/nfs_fs_sb.h
+++ b/include/linux/nfs_fs_sb.h
@@ -197,6 +197,7 @@ struct nfs4_slot_table {
                                                  * op for dynamic resizing */
         int             target_max_slots;       /* Set by CB_RECALL_SLOT as
                                                  * the new max_slots */
+        struct completion complete;
 };
 
 static inline int slot_idx(struct nfs4_slot_table *tbl, struct nfs4_slot *sp)
@@ -213,7 +214,6 @@ struct nfs4_session {
         unsigned long                   session_state;
         u32                             hash_alg;
         u32                             ssv_len;
-        struct completion               complete;
 
         /* The fore and back channel */
         struct nfs4_channel_attrs       fc_attrs;