NFSv4.2: Fix 5 seconds delay when doing inter server copy

Since commit b4868b44c5 ("NFSv4: Wait for stateid updates after
CLOSE/OPEN_DOWNGRADE"), every inter server copy operation suffers 5
seconds delay regardless of the size of the copy. The delay is from
nfs_set_open_stateid_locked when the check by nfs_stateid_is_sequential
fails because the seqid in both nfs4_state and nfs4_stateid are 0.

Fix __nfs42_ssc_open to delay setting of NFS_OPEN_STATE in nfs4_state,
until after the call to update_open_stateid, to indicate this is the 1st
open. This fix is part of a 2 patches, the other patch is the fix in the
source server to return the stateid for COPY_NOTIFY request with seqid 1
instead of 0.

Fixes: ce0887ac96 ("NFSD add nfs4 inter ssc to nfsd4_copy")
Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

fs/nfs/nfs4file.c

@@ -377,10 +377,10 @@ static struct file *__nfs42_ssc_open(struct vfsmount *ss_mnt,
 		goto out_stateowner;
 
 	set_bit(NFS_SRV_SSC_COPY_STATE, &ctx->state->flags);
-	set_bit(NFS_OPEN_STATE, &ctx->state->flags);
 	memcpy(&ctx->state->open_stateid.other, &stateid->other,
 	       NFS4_STATEID_OTHER_SIZE);
 	update_open_stateid(ctx->state, stateid, NULL, filep->f_mode);
+	set_bit(NFS_OPEN_STATE, &ctx->state->flags);
 
 	nfs_file_set_open_context(filep, ctx);
 	put_nfs_open_context(ctx);