pNFS: Files and flexfiles always need to commit before layoutcommit

So ensure that we mark the layout for commit once the write is done,
and then ensure that the commit to ds is finished before sending
layoutcommit.

Note that by doing this, we're able to optimise away the commit
for the case of servers that don't need layoutcommit in order to
return updated attributes.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

fs/nfs/filelayout/filelayout.c

@@ -255,13 +255,16 @@ static int filelayout_read_done_cb(struct rpc_task *task,
 static void
 filelayout_set_layoutcommit(struct nfs_pgio_header *hdr)
 {
+	loff_t end_offs = 0;
 
 	if (FILELAYOUT_LSEG(hdr->lseg)->commit_through_mds ||
-	    hdr->res.verf->committed != NFS_DATA_SYNC)
+	    hdr->res.verf->committed == NFS_FILE_SYNC)
 		return;
+	if (hdr->res.verf->committed == NFS_DATA_SYNC)
+		end_offs = hdr->mds_offset + (loff_t)hdr->res.count;
 
-	pnfs_set_layoutcommit(hdr->inode, hdr->lseg,
-			hdr->mds_offset + hdr->res.count);
+	/* Note: if the write is unstable, don't set end_offs until commit */
+	pnfs_set_layoutcommit(hdr->inode, hdr->lseg, end_offs);
 	dprintk("%s inode %lu pls_end_pos %lu\n", __func__, hdr->inode->i_ino,
 		(unsigned long) NFS_I(hdr->inode)->layout->plh_lwb);
 }

fs/nfs/flexfilelayout/flexfilelayout.c

@@ -1470,6 +1470,7 @@ static void ff_layout_read_release(void *data)
 static int ff_layout_write_done_cb(struct rpc_task *task,
 				struct nfs_pgio_header *hdr)
 {
+	loff_t end_offs = 0;
 	int err;
 
 	trace_nfs4_pnfs_write(hdr, task->tk_status);
@@ -1495,8 +1496,10 @@ static int ff_layout_write_done_cb(struct rpc_task *task,
 
 	if (hdr->res.verf->committed == NFS_FILE_SYNC ||
 	    hdr->res.verf->committed == NFS_DATA_SYNC)
-		ff_layout_set_layoutcommit(hdr->inode, hdr->lseg,
-				hdr->mds_offset + (loff_t)hdr->res.count);
+		end_offs = hdr->mds_offset + (loff_t)hdr->res.count;
+
+	/* Note: if the write is unstable, don't set end_offs until commit */
+	ff_layout_set_layoutcommit(hdr->inode, hdr->lseg, end_offs);
 
 	/* zero out fattr since we don't care DS attr at all */
 	hdr->fattr.valid = 0;

fs/nfs/nfs4xdr.c

@@ -1985,9 +1985,14 @@ encode_layoutcommit(struct xdr_stream *xdr,
 	p = xdr_encode_hyper(p, args->lastbytewritten + 1);	/* length */
 	*p = cpu_to_be32(0); /* reclaim */
 	encode_nfs4_stateid(xdr, &args->stateid);
-	p = reserve_space(xdr, 20);
-	*p++ = cpu_to_be32(1); /* newoffset = TRUE */
-	p = xdr_encode_hyper(p, args->lastbytewritten);
+	if (args->lastbytewritten != U64_MAX) {
+		p = reserve_space(xdr, 20);
+		*p++ = cpu_to_be32(1); /* newoffset = TRUE */
+		p = xdr_encode_hyper(p, args->lastbytewritten);
+	} else {
+		p = reserve_space(xdr, 12);
+		*p++ = cpu_to_be32(0); /* newoffset = FALSE */
+	}
 	*p++ = cpu_to_be32(0); /* Never send time_modify_changed */
 	*p++ = cpu_to_be32(NFS_SERVER(args->inode)->pnfs_curr_ld->id);/* type */
 

fs/nfs/pnfs.c

@@ -2378,7 +2378,10 @@ pnfs_layoutcommit_inode(struct inode *inode, bool sync)
 	nfs_fattr_init(&data->fattr);
 	data->args.bitmask = NFS_SERVER(inode)->cache_consistency_bitmask;
 	data->res.fattr = &data->fattr;
-	data->args.lastbytewritten = end_pos - 1;
+	if (end_pos != 0)
+		data->args.lastbytewritten = end_pos - 1;
+	else
+		data->args.lastbytewritten = U64_MAX;
 	data->res.server = NFS_SERVER(inode);
 
 	if (ld->prepare_layoutcommit) {

fs/nfs/pnfs_nfs.c

@@ -932,6 +932,13 @@ EXPORT_SYMBOL_GPL(pnfs_layout_mark_request_commit);
 int
 pnfs_nfs_generic_sync(struct inode *inode, bool datasync)
 {
+	int ret;
+
+	if (!pnfs_layoutcommit_outstanding(inode))
+		return 0;
+	ret = nfs_commit_inode(inode, FLUSH_SYNC);
+	if (ret < 0)
+		return ret;
 	if (datasync)
 		return 0;
 	return pnfs_layoutcommit_inode(inode, true);