pnfs: set NFS_IOHDR_REDO in pnfs_read_resend_pnfs

Like other resend paths, mark the (old) hdr as NFS_IOHDR_REDO. This
ensures the hdr completion function will not count the (old) hdr
as good bytes.

Also, vector the error back through the hdr->task.tk_status like other
retry calls.

This fixes a bug with the FlexFiles layout where libaio was reporting more
bytes read than requested.
Signed-off-by: NWeston Andros Adamson <dros@primarydata.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

fs/nfs/pnfs.c

@@ -2143,12 +2143,15 @@ pnfs_try_to_read_data(struct nfs_pgio_header *hdr,
 }
 
 /* Resend all requests through pnfs. */
-int pnfs_read_resend_pnfs(struct nfs_pgio_header *hdr)
+void pnfs_read_resend_pnfs(struct nfs_pgio_header *hdr)
 {
 	struct nfs_pageio_descriptor pgio;
 
-	nfs_pageio_init_read(&pgio, hdr->inode, false, hdr->completion_ops);
-	return nfs_pageio_resend(&pgio, hdr);
+	if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
+		nfs_pageio_init_read(&pgio, hdr->inode, false,
+					hdr->completion_ops);
+		hdr->task.tk_status = nfs_pageio_resend(&pgio, hdr);
+	}
 }
 EXPORT_SYMBOL_GPL(pnfs_read_resend_pnfs);
 
@@ -2158,12 +2161,11 @@ pnfs_do_read(struct nfs_pageio_descriptor *desc, struct nfs_pgio_header *hdr)
 	const struct rpc_call_ops *call_ops = desc->pg_rpc_callops;
 	struct pnfs_layout_segment *lseg = desc->pg_lseg;
 	enum pnfs_try_status trypnfs;
-	int err = 0;
 
 	trypnfs = pnfs_try_to_read_data(hdr, call_ops, lseg);
 	if (trypnfs == PNFS_TRY_AGAIN)
-		err = pnfs_read_resend_pnfs(hdr);
-	if (trypnfs == PNFS_NOT_ATTEMPTED || err)
+		pnfs_read_resend_pnfs(hdr);
+	if (trypnfs == PNFS_NOT_ATTEMPTED || hdr->task.tk_status)
 		pnfs_read_through_mds(desc, hdr);
 }
 

fs/nfs/pnfs.h

@@ -282,7 +282,7 @@ int _pnfs_return_layout(struct inode *);
 int pnfs_commit_and_return_layout(struct inode *);
 void pnfs_ld_write_done(struct nfs_pgio_header *);
 void pnfs_ld_read_done(struct nfs_pgio_header *);
-int pnfs_read_resend_pnfs(struct nfs_pgio_header *);
+void pnfs_read_resend_pnfs(struct nfs_pgio_header *);
 struct pnfs_layout_segment *pnfs_update_layout(struct inode *ino,
 					       struct nfs_open_context *ctx,
 					       loff_t pos,