nfsd: don't hold ls_mutex across a layout recall

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: cc8a55320b5f "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
index 9ffef06b30d51e2acb2ae1a6570f14c2c47eac59..c9d6c715c0fb7e3187ffd1f2105f9527aa32259b 100644 (file)
--- 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);