NFS: Fix a page leak in nfs_destroy_unlinked_subrequests()

When we detach a subrequest from the list, we must also release the
reference it holds to the parent.

Fixes: 5b2b5187fa85 ("NFS: Fix nfs_page_group_destroy() and nfs_lock_and_join_requests() race cases")
Cc: stable@vger.kernel.org # v4.14+
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 03b7f64..626e99c 100644 (file)
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -444,6 +444,7 @@ nfs_destroy_unlinked_subrequests(struct nfs_page *destroy_list,
                }
 
                subreq->wb_head = subreq;
+               nfs_release_request(old_head);
 
                if (test_and_clear_bit(PG_INODE_REF, &subreq->wb_flags)) {
                        nfs_release_request(subreq);