NFS/localio: Stop further I/O upon hitting an error

If the call into the filesystem results in an I/O error, then the next
chunk of data won't be contiguous with the end of the last successful
chunk. So break out of the I/O loop and report the results.
Currently the localio code will do this for a short read/write, but not
for an error.

Fixes: 6a218b9 ("nfs/localio: do not issue misaligned DIO out-of-order")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Reviewed-by: Mike Snitzer <snitzer@kernel.org>

Author: Trond Myklebust

fs/nfs/localio.c

@@ -618,7 +618,6 @@ static void nfs_local_call_read(struct work_struct *work)
 	struct nfs_local_kiocb *iocb =
 		container_of(work, struct nfs_local_kiocb, work);
 	struct file *filp = iocb->kiocb.ki_filp;
-	bool force_done = false;
 	ssize_t status;
 	int n_iters;
 
@@ -637,13 +636,13 @@ static void nfs_local_call_read(struct work_struct *work)
 		scoped_with_creds(filp->f_cred)
 			status = filp->f_op->read_iter(&iocb->kiocb, &iocb->iters[i]);
 
-		if (status != -EIOCBQUEUED) {
-			if (unlikely(status >= 0 && status < iocb->iters[i].count))
-				force_done = true; /* Partial read */
-			if (nfs_local_pgio_done(iocb, status, force_done)) {
-				nfs_local_read_iocb_done(iocb);
-				break;
-			}
+		if (status == -EIOCBQUEUED)
+			continue;
+		/* Break on completion, errors, or short reads */
+		if (nfs_local_pgio_done(iocb, status, false) || status < 0 ||
+		    (size_t)status < iov_iter_count(&iocb->iters[i])) {
+			nfs_local_read_iocb_done(iocb);
+			break;
 		}
 	}
 }
@@ -821,7 +820,6 @@ static void nfs_local_call_write(struct work_struct *work)
 		container_of(work, struct nfs_local_kiocb, work);
 	struct file *filp = iocb->kiocb.ki_filp;
 	unsigned long old_flags = current->flags;
-	bool force_done = false;
 	ssize_t status;
 	int n_iters;
 
@@ -843,13 +841,13 @@ static void nfs_local_call_write(struct work_struct *work)
 		scoped_with_creds(filp->f_cred)
 			status = filp->f_op->write_iter(&iocb->kiocb, &iocb->iters[i]);
 
-		if (status != -EIOCBQUEUED) {
-			if (unlikely(status >= 0 && status < iocb->iters[i].count))
-				force_done = true; /* Partial write */
-			if (nfs_local_pgio_done(iocb, status, force_done)) {
-				nfs_local_write_iocb_done(iocb);
-				break;
-			}
+		if (status == -EIOCBQUEUED)
+			continue;
+		/* Break on completion, errors, or short writes */
+		if (nfs_local_pgio_done(iocb, status, false) || status < 0 ||
+		    (size_t)status < iov_iter_count(&iocb->iters[i])) {
+			nfs_local_write_iocb_done(iocb);
+			break;
 		}
 	}
 	file_end_write(filp);