ceph: add get_parent() NFS export callback

The callback uses LOOKUPPARENT MDS request to find parent.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Sage Weil <sage@inktank.com>

diff --git a/fs/ceph/export.c b/fs/ceph/export.c
index 976d341..9c28b6a 100644 (file)
--- a/fs/ceph/export.c
+++ b/fs/ceph/export.c
@@ -121,6 +121,65 @@ static struct dentry *ceph_fh_to_dentry(struct super_block *sb,
        return __fh_to_dentry(sb, fh->ino);
 }
 
+static struct dentry *__get_parent(struct super_block *sb,
+                                  struct dentry *child, u64 ino)
+{
+       struct ceph_mds_client *mdsc = ceph_sb_to_client(sb)->mdsc;
+       struct ceph_mds_request *req;
+       struct inode *inode;
+       struct dentry *dentry;
+       int err;
+
+       req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPPARENT,
+                                      USE_ANY_MDS);
+       if (IS_ERR(req))
+               return ERR_CAST(req);
+
+       if (child) {
+               req->r_inode = child->d_inode;
+               ihold(child->d_inode);
+       } else {
+               req->r_ino1 = (struct ceph_vino) {
+                       .ino = ino,
+                       .snap = CEPH_NOSNAP,
+               };
+       }
+       req->r_num_caps = 1;
+       err = ceph_mdsc_do_request(mdsc, NULL, req);
+       inode = req->r_target_inode;
+       if (inode)
+               ihold(inode);
+       ceph_mdsc_put_request(req);
+       if (!inode)
+               return ERR_PTR(-ENOENT);
+
+       dentry = d_obtain_alias(inode);
+       if (IS_ERR(dentry)) {
+               iput(inode);
+               return dentry;
+       }
+       err = ceph_init_dentry(dentry);
+       if (err < 0) {
+               dput(dentry);
+               return ERR_PTR(err);
+       }
+       dout("__get_parent ino %llx parent %p ino %llx.%llx\n",
+            child ? ceph_ino(child->d_inode) : ino,
+            dentry, ceph_vinop(inode));
+       return dentry;
+}
+
+struct dentry *ceph_get_parent(struct dentry *child)
+{
+       /* don't re-export snaps */
+       if (ceph_snap(child->d_inode) != CEPH_NOSNAP)
+               return ERR_PTR(-EINVAL);
+
+       dout("get_parent %p ino %llx.%llx\n",
+            child, ceph_vinop(child->d_inode));
+       return __get_parent(child->d_sb, child, 0);
+}
+
 /*
  * get parent, if possible.
  *
@@ -171,4 +230,5 @@ 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,
 };