[v1,36/38] nfs: add a get_parent export operation for NFS

Commit Message

Jeff Layton Nov. 17, 2015, 11:52 a.m. UTC

In order to connect disconnected dentries into the tree, we must be
able to determine their parent. Add a get_parent routine for NFS
which does a LOOKUPP operation (in the case of NFSv4), finds the
parent inode and then obtains the dentry for it.

Signed-off-by: Jeff Layton <[e-mail]>
---
 fs/nfs/export.c | 43 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)

Patch

diff --git a/fs/nfs/export.c b/fs/nfs/export.c
index a40a9fc31d13..e1c8165652c5 100644
--- a/fs/nfs/export.c
+++ b/fs/nfs/export.c
@@ -119,8 +119,51 @@  out:
 	return ret ? ERR_PTR(ret) : dentry;
 }
 
+static struct dentry *
+nfs_get_parent(struct dentry *dentry)
+{
+	int ret;
+	struct inode *inode = d_inode(dentry), *pinode;
+	struct super_block *sb = inode->i_sb;
+	struct nfs_server *server = NFS_SB(sb);
+	struct nfs_fattr *fattr = NULL;
+	struct nfs4_label *label = NULL;
+	struct dentry *parent;
+	struct nfs_rpc_ops const *ops = server->nfs_client->rpc_ops;
+	struct nfs_fh fh;
+
+	if (!ops->lookupp)
+		return ERR_PTR(-EACCES);
+
+	fattr = nfs_alloc_fattr();
+	if (fattr == NULL) {
+		parent = ERR_PTR(-ENOMEM);
+		goto out;
+	}
+
+	label = nfs4_label_alloc(server, GFP_KERNEL);
+	if (IS_ERR(label)) {
+		parent = ERR_CAST(label);
+		goto out;
+	}
+
+	ret = ops->lookupp(inode, &fh, fattr, label);
+	if (ret) {
+		parent = ERR_PTR(ret);
+		goto out;
+	}
+
+	pinode = nfs_fhget(sb, &fh, fattr, label);
+	parent = d_obtain_alias(pinode);
+out:
+	nfs4_label_free(label);
+	nfs_free_fattr(fattr);
+	return parent;
+}
+
 const struct export_operations nfs_export_ops = {
 	.encode_fh = nfs_encode_fh,
 	.fh_to_dentry = nfs_fh_to_dentry,
+	.get_parent = nfs_get_parent,
 	.flags = EXPORT_OP_NOWCC|EXPORT_OP_NOSUBTREECHK|EXPORT_OP_CLOSE_BEFORE_UNLINK,
 };