nfs: properly protect nfs_direct_req fields

We protect accesses to the nfs_direct_req fields with the dreq->lock
ever where except nfs_direct_commit_complete.  This isn't a huge deal,
but it does lead to confusion, and we could potentially end up setting
NFS_ODIRECT_RESCHED_WRITES in one thread where we've had an error in
another.  Clean this up to properly protect ->error and ->flags in the
commit completion path.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index c03926a1cc73bc42af75cfa9e0fba8dc5b134258..befcc167e25fec89fe6e509a41dfb07f7ad94c53 100644 (file)
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -606,6 +606,7 @@ static void nfs_direct_commit_complete(struct nfs_commit_data *data)
 
        trace_nfs_direct_commit_complete(dreq);
 
+       spin_lock(&dreq->lock);
        if (status < 0) {
                /* Errors in commit are fatal */
                dreq->error = status;
@@ -613,6 +614,7 @@ static void nfs_direct_commit_complete(struct nfs_commit_data *data)
        } else {
                status = dreq->error;
        }
+       spin_unlock(&dreq->lock);
 
        nfs_init_cinfo_from_dreq(&cinfo, dreq);
 
@@ -625,7 +627,10 @@ static void nfs_direct_commit_complete(struct nfs_commit_data *data)
                        spin_unlock(&dreq->lock);
                        nfs_release_request(req);
                } else if (!nfs_write_match_verf(verf, req)) {
-                       dreq->flags = NFS_ODIRECT_RESCHED_WRITES;
+                       spin_lock(&dreq->lock);
+                       if (dreq->flags == 0)
+                               dreq->flags = NFS_ODIRECT_RESCHED_WRITES;
+                       spin_unlock(&dreq->lock);
                        /*
                         * Despite the reboot, the write was successful,
                         * so reset wb_nio.