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>

1 files changed, 5 insertions, 2 deletions

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);