Commit 88975a55 authored by Trond Myklebust's avatar Trond Myklebust Committed by Anna Schumaker
Browse files

NFS: Fix a potential data corruption 



We must ensure that the subrequests are joined back into the head before
we can retransmit a request. If the head was not on the commit lists,
because the server wrote it synchronously, we still need to add it back
to the retransmission list.
Add a call that mirrors the effect of nfs_cancel_remove_inode() for
O_DIRECT.

Fixes: ed5d588f ("NFS: Try to join page groups before an O_DIRECT retransmission")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
parent 14e7316a

fs/nfs/direct.c

+19 −1
Original line number Diff line number Diff line
@@ -472,13 +472,31 @@ ssize_t nfs_file_direct_read(struct kiocb *iocb, struct iov_iter *iter, 
	return result;

}



static void nfs_direct_add_page_head(struct list_head *list,

				     struct nfs_page *req)

{

	struct nfs_page *head = req->wb_head;



	if (!list_empty(&head->wb_list) || !nfs_lock_request(head))

		return;

	if (!list_empty(&head->wb_list)) {

		nfs_unlock_request(head);

		return;

	}

	list_add(&head->wb_list, list);

	kref_get(&head->wb_kref);

	kref_get(&head->wb_kref);

}



static void nfs_direct_join_group(struct list_head *list, struct inode *inode)

{

	struct nfs_page *req, *subreq;



	list_for_each_entry(req, list, wb_list) {

		if (req->wb_head != req)

		if (req->wb_head != req) {

			nfs_direct_add_page_head(&req->wb_list, req);

			continue;

		}

		subreq = req->wb_this_page;

		if (subreq == req)

			continue;