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>

1 files changed, 60 insertions, 0 deletions

diff --git a/fs/ceph/export.c b/fs/ceph/export.c
index 976d3411d5ed..9c28b6abe885 100644
--- 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,
 };