From ed3743a6d4f309f5278c87a69e3125382b78455c Mon Sep 17 00:00:00 2001
From: Weston Andros Adamson <dros@primarydata.com>
Date: Fri, 1 Apr 2016 11:42:29 -0400
Subject: nfs: add debug to directio "good_bytes" counting

This will pop a warning if we count too many good bytes.

Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
---
 fs/nfs/direct.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

(limited to 'fs/nfs/direct.c')

diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index c93826e4a8c6..f79d98ae4c10 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -87,6 +87,7 @@ struct nfs_direct_req {
 	int			mirror_count;
 
 	ssize_t			count,		/* bytes actually processed */
+				max_count,	/* max expected count */
 				bytes_left,	/* bytes left to be sent */
 				io_start,	/* start of IO */
 				error;		/* any reported error */
@@ -123,6 +124,8 @@ nfs_direct_good_bytes(struct nfs_direct_req *dreq, struct nfs_pgio_header *hdr)
 	int i;
 	ssize_t count;
 
+	WARN_ON_ONCE(dreq->count >= dreq->max_count);
+
 	if (dreq->mirror_count == 1) {
 		dreq->mirrors[hdr->pgio_mirror_idx].count += hdr->good_bytes;
 		dreq->count += hdr->good_bytes;
@@ -593,7 +596,7 @@ ssize_t nfs_file_direct_read(struct kiocb *iocb, struct iov_iter *iter,
 		goto out_unlock;
 
 	dreq->inode = inode;
-	dreq->bytes_left = count;
+	dreq->bytes_left = dreq->max_count = count;
 	dreq->io_start = pos;
 	dreq->ctx = get_nfs_open_context(nfs_file_open_context(iocb->ki_filp));
 	l_ctx = nfs_get_lock_context(dreq->ctx);
@@ -1026,7 +1029,7 @@ ssize_t nfs_file_direct_write(struct kiocb *iocb, struct iov_iter *iter)
 		goto out_unlock;
 
 	dreq->inode = inode;
-	dreq->bytes_left = iov_iter_count(iter);
+	dreq->bytes_left = dreq->max_count = iov_iter_count(iter);
 	dreq->io_start = pos;
 	dreq->ctx = get_nfs_open_context(nfs_file_open_context(iocb->ki_filp));
 	l_ctx = nfs_get_lock_context(dreq->ctx);
-- 
cgit