nfsd: don't hold ls_mutex across a layout recall

jtlayton · J. Bruce Fields · commit be20aa00c671 · 2015-12-16T11:49:58.000-05:00
We do need to serialize layout stateid morphing operations, but we currently hold the ls_mutex across a layout recall which is pretty ugly. It's also unnecessary -- once we've bumped the seqid and copied it, we don't need to serialize the rest of the CB_LAYOUTRECALL vs. anything else. Just drop the mutex once the copy is done. This was causing a "workqueue leaked lock or atomic" warning and an occasional deadlock. There's more work to be done here but this fixes the immediate regression. Fixes: cc8a553 "nfsd: serialize layout stateid morphing operations" Cc: stable@vger.kernel.org Reported-by: Kinglong Mee <kinglongmee@gmail.com> Signed-off-by: Jeff Layton <jeff.layton@primarydata.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfsd/nfs4layouts.c b/fs/nfsd/nfs4layouts.c
@@ -616,6 +616,7 @@ nfsd4_cb_layout_prepare(struct nfsd4_callback *cb)
 
 	mutex_lock(&ls->ls_mutex);
 	nfs4_inc_and_copy_stateid(&ls->ls_recall_sid, &ls->ls_stid);
+	mutex_unlock(&ls->ls_mutex);
 }
 
 static int
@@ -659,7 +660,6 @@ nfsd4_cb_layout_release(struct nfsd4_callback *cb)
 
 	trace_layout_recall_release(&ls->ls_stid.sc_stateid);
 
-	mutex_unlock(&ls->ls_mutex);
 	nfsd4_return_all_layouts(ls, &reaplist);
 	nfsd4_free_layouts(&reaplist);
 	nfs4_put_stid(&ls->ls_stid);
