[PATCH 17/26] netfs: Fix writethrough-mode error handling

[David Howells <dhowells@redhat.com>]

Fix the error return in netfs_perform_write() acting in writethrough-mode
to return any cached error in the case that netfs_end_writethrough()
returns 0.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
---
 fs/netfs/buffered_write.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/fs/netfs/buffered_write.c b/fs/netfs/buffered_write.c
index 8e4a3fb287e3..db4ad158948b 100644
--- a/fs/netfs/buffered_write.c
+++ b/fs/netfs/buffered_write.c
@@ -188,7 +188,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 	enum netfs_how_to_modify howto;
 	enum netfs_folio_trace trace;
 	unsigned int bdp_flags = (iocb->ki_flags & IOCB_SYNC) ? 0: BDP_ASYNC;
-	ssize_t written = 0, ret;
+	ssize_t written = 0, ret, ret2;
 	loff_t i_size, pos = iocb->ki_pos, from, to;
 	size_t max_chunk = PAGE_SIZE << MAX_PAGECACHE_ORDER;
 	bool maybe_trouble = false;
@@ -409,10 +409,12 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 
 out:
 	if (unlikely(wreq)) {
-		ret = netfs_end_writethrough(wreq, iocb);
+		ret2 = netfs_end_writethrough(wreq, iocb);
 		wbc_detach_inode(&wbc);
-		if (ret == -EIOCBQUEUED)
-			return ret;
+		if (ret2 == -EIOCBQUEUED)
+			return ret2;
+		if (ret == 0)
+			ret = ret2;
 	}
 
 	iocb->ki_pos += written;