[PATCH] knfsd: nfsd4: delegation recovery

Allow recovery of delegations after reboot.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/nfsd/nfs4state.c

@@ -1709,14 +1709,30 @@ nfs4_open_delegation(struct svc_fh *fh, struct nfsd4_open *open, struct nfs4_sta
 	int status, flag = 0;
 
 	flag = NFS4_OPEN_DELEGATE_NONE;
-	if (open->op_claim_type != NFS4_OPEN_CLAIM_NULL
-	     || !atomic_read(&cb->cb_set) || !sop->so_confirmed)
-		goto out;
-
-	if (open->op_share_access & NFS4_SHARE_ACCESS_WRITE)
-		flag = NFS4_OPEN_DELEGATE_WRITE;
-	else
-		flag = NFS4_OPEN_DELEGATE_READ;
+	open->op_recall = 0;
+	switch (open->op_claim_type) {
+		case NFS4_OPEN_CLAIM_PREVIOUS:
+			if (!atomic_read(&cb->cb_set))
+				open->op_recall = 1;
+			flag = open->op_delegate_type;
+			if (flag == NFS4_OPEN_DELEGATE_NONE)
+				goto out;
+			break;
+		case NFS4_OPEN_CLAIM_NULL:
+			/* Let's not give out any delegations till everyone's
+			 * had the chance to reclaim theirs.... */
+			if (nfs4_in_grace())
+				goto out;
+			if (!atomic_read(&cb->cb_set) || !sop->so_confirmed)
+				goto out;
+			if (open->op_share_access & NFS4_SHARE_ACCESS_WRITE)
+				flag = NFS4_OPEN_DELEGATE_WRITE;
+			else
+				flag = NFS4_OPEN_DELEGATE_READ;
+			break;
+		default:
+			goto out;
+	}
 
 	dp = alloc_init_deleg(sop->so_client, stp, fh, flag);
 	if (dp == NULL) {
@@ -1750,6 +1766,10 @@ nfs4_open_delegation(struct svc_fh *fh, struct nfsd4_open *open, struct nfs4_sta
 	             dp->dl_stateid.si_fileid,
 	             dp->dl_stateid.si_generation);
 out:
+	if (open->op_claim_type == NFS4_OPEN_CLAIM_PREVIOUS
+			&& flag == NFS4_OPEN_DELEGATE_NONE
+			&& open->op_delegate_type != NFS4_OPEN_DELEGATE_NONE)
+		printk("NFSD: WARNING: refusing delegation reclaim\n");
 	open->op_delegate_type = flag;
 }
 

fs/nfsd/nfs4xdr.c

@@ -1972,7 +1972,7 @@ nfsd4_encode_open(struct nfsd4_compoundres *resp, int nfserr, struct nfsd4_open
 	case NFS4_OPEN_DELEGATE_READ:
 		RESERVE_SPACE(20 + sizeof(stateid_t));
 		WRITEMEM(&open->op_delegate_stateid, sizeof(stateid_t));
-		WRITE32(0);
+		WRITE32(open->op_recall);
 
 		/*
 		 * TODO: ACE's in delegations

include/linux/nfsd/xdr4.h

@@ -210,6 +210,7 @@ struct nfsd4_open {
 	u32		op_share_access;    /* request */
 	u32		op_share_deny;      /* request */
 	stateid_t	op_stateid;         /* response */
+	u32		op_recall;          /* recall */
 	struct nfsd4_change_info  op_cinfo; /* response */
 	u32		op_rflags;          /* response */
 	int		op_truncate;        /* used during processing */