[PATCH] ceph: add get_name() NFS export callback

["Yan, Zheng" <zheng.z.yan@intel.com>]

Set WANT_DENTRY flag for the LOOKUPINO MDS request. The flag makes
MDS reply contain dentry trace.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
---
 fs/ceph/export.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
 fs/ceph/inode.c  | 51 ++++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 95 insertions(+), 1 deletion(-)

diff --git a/fs/ceph/export.c b/fs/ceph/export.c
index 4ec1fd5..3c84b49 100644
--- a/fs/ceph/export.c
+++ b/fs/ceph/export.c
@@ -183,9 +183,54 @@ static struct dentry *ceph_get_parent(struct dentry *child)
 	return dentry;
 }
 
+static int ceph_get_name(struct dentry *parent, char *name,
+			 struct dentry *child)
+{
+	struct ceph_mds_client *mdsc;
+	struct ceph_mds_request *req;
+	int err;
+
+	mdsc = ceph_inode_to_client(child->d_inode)->mdsc;
+	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPINO,
+				       USE_ANY_MDS);
+	if (IS_ERR(req))
+		return PTR_ERR(req);
+
+	mutex_lock(&parent->d_inode->i_mutex);
+
+	req->r_inode = child->d_inode;
+	ihold(child->d_inode);
+	req->r_ino2 = ceph_vino(parent->d_inode);
+	req->r_locked_dir = parent->d_inode;
+	req->r_num_caps = 1;
+	err = ceph_mdsc_do_request(mdsc, NULL, req);
+
+	mutex_unlock(&parent->d_inode->i_mutex);
+
+	if (!err) {
+		struct ceph_mds_reply_info_parsed *rinfo = &req->r_reply_info;
+		if (rinfo->head->is_dentry) {
+			memcpy(name, rinfo->dname, rinfo->dname_len);
+			name[rinfo->dname_len] = 0;
+		} else {
+			err = -EOPNOTSUPP;
+		}
+	}
+	ceph_mdsc_put_request(req);
+
+	if (!err)
+		dout("get_name child %p ino %llx.%llx name %s\n",
+		     child, ceph_vinop(child->d_inode), name);
+	else
+		dout("get_name child %p ino %llx.%llx err %d\n",
+		     child, ceph_vinop(child->d_inode), err);
+	return err;
+}
+
 const struct export_operations ceph_export_ops = {
 	.encode_fh = ceph_encode_fh,
 	.fh_to_dentry = ceph_fh_to_dentry,
 	.fh_to_parent = ceph_fh_to_parent,
 	.get_parent = ceph_get_parent,
+	.get_name = ceph_get_name,
 };
diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index 8bf2384..ff3ee3e 100644
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -1044,10 +1044,59 @@ int ceph_fill_trace(struct super_block *sb, struct ceph_mds_request *req,
 					 session, req->r_request_started, -1,
 					 &req->r_caps_reservation);
 			if (err < 0)
-				return err;
+				goto done;
 		} else {
 			WARN_ON_ONCE(1);
 		}
+
+		if (dir && req->r_op == CEPH_MDS_OP_LOOKUPINO) {
+			struct qstr dname;
+			struct dentry *dn, *parent;
+
+			BUG_ON(!rinfo->head->is_target);
+			BUG_ON(req->r_dentry);
+
+			parent = d_find_any_alias(dir);
+			BUG_ON(!parent);
+
+			dname.name = rinfo->dname;
+			dname.len = rinfo->dname_len;
+			dname.hash = full_name_hash(dname.name, dname.len);
+			vino.ino = le64_to_cpu(rinfo->targeti.in->ino);
+			vino.snap = le64_to_cpu(rinfo->targeti.in->snapid);
+retry_lookup:
+			dn = d_lookup(parent, &dname);
+			dout("d_lookup on parent=%p name=%.*s got %p\n",
+			     parent, dname.len, dname.name, dn);
+
+			if (!dn) {
+				dn = d_alloc(parent, &dname);
+				dout("d_alloc %p '%.*s' = %p\n", parent,
+				     dname.len, dname.name, dn);
+				if (dn == NULL) {
+					dput(parent);
+					err = -ENOMEM;
+					goto done;
+				}
+				err = ceph_init_dentry(dn);
+				if (err < 0) {
+					dput(dn);
+					dput(parent);
+					goto done;
+				}
+			} else if (dn->d_inode &&
+				   (ceph_ino(dn->d_inode) != vino.ino ||
+				    ceph_snap(dn->d_inode) != vino.snap)) {
+				dout(" dn %p points to wrong inode %p\n",
+				     dn, dn->d_inode);
+				d_delete(dn);
+				dput(dn);
+				goto retry_lookup;
+			}
+
+			req->r_dentry = dn;
+			dput(parent);
+		}
 	}
 
 	if (rinfo->head->is_target) {
-- 
1.8.5.3