NFS: Add a lookupfh NFS RPC op

Add a lookup filehandle NFS RPC op so that a file handle can be looked up
without requiring dentries and inodes and other VFS stuff when doing an NFS4
pathwalk during mounting.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index b46597f..de2006f 100644 (file)
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -1583,6 +1583,52 @@ nfs4_proc_setattr(struct dentry *dentry, struct nfs_fattr *fattr,
        return status;
 }
 
+static int _nfs4_proc_lookupfh(struct nfs_server *server, struct nfs_fh *dirfh,
+               struct qstr *name, struct nfs_fh *fhandle,
+               struct nfs_fattr *fattr)
+{
+       int                    status;
+       struct nfs4_lookup_arg args = {
+               .bitmask = server->attr_bitmask,
+               .dir_fh = dirfh,
+               .name = name,
+       };
+       struct nfs4_lookup_res res = {
+               .server = server,
+               .fattr = fattr,
+               .fh = fhandle,
+       };
+       struct rpc_message msg = {
+               .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_LOOKUP],
+               .rpc_argp = &args,
+               .rpc_resp = &res,
+       };
+
+       nfs_fattr_init(fattr);
+
+       dprintk("NFS call  lookupfh %s\n", name->name);
+       status = rpc_call_sync(server->client, &msg, 0);
+       dprintk("NFS reply lookupfh: %d\n", status);
+       if (status == -NFS4ERR_MOVED)
+               status = -EREMOTE;
+       return status;
+}
+
+static int nfs4_proc_lookupfh(struct nfs_server *server, struct nfs_fh *dirfh,
+                             struct qstr *name, struct nfs_fh *fhandle,
+                             struct nfs_fattr *fattr)
+{
+       struct nfs4_exception exception = { };
+       int err;
+       do {
+               err = nfs4_handle_exception(server,
+                               _nfs4_proc_lookupfh(server, dirfh, name,
+                                                   fhandle, fattr),
+                               &exception);
+       } while (exception.retry);
+       return err;
+}
+
 static int _nfs4_proc_lookup(struct inode *dir, struct qstr *name,
                struct nfs_fh *fhandle, struct nfs_fattr *fattr)
 {
@@ -3723,6 +3769,7 @@ struct nfs_rpc_ops        nfs_v4_clientops = {
        .getroot        = nfs4_proc_get_root,
        .getattr        = nfs4_proc_getattr,
        .setattr        = nfs4_proc_setattr,
+       .lookupfh       = nfs4_proc_lookupfh,
        .lookup         = nfs4_proc_lookup,
        .access         = nfs4_proc_access,
        .readlink       = nfs4_proc_readlink,

diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
index 41e5a19..2687977 100644 (file)
--- a/include/linux/nfs_xdr.h
+++ b/include/linux/nfs_xdr.h
@@ -770,6 +770,9 @@ struct nfs_rpc_ops {
 
        int     (*getroot) (struct nfs_server *, struct nfs_fh *,
                            struct nfs_fsinfo *);
+       int     (*lookupfh)(struct nfs_server *, struct nfs_fh *,
+                           struct qstr *, struct nfs_fh *,
+                           struct nfs_fattr *);
        int     (*getattr) (struct nfs_server *, struct nfs_fh *,
                            struct nfs_fattr *);
        int     (*setattr) (struct dentry *, struct nfs_fattr *,