NFS: Allow the NFS generic code to pass in a verifier to readdir

If we're ever going to allow support for servers that use the readdir
verifier, then that use needs to be managed by the middle layers as
those need to be able to reject cookies from other verifiers.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Tested-by: Benjamin Coddington <bcodding@redhat.com>
Tested-by: Dave Wysochanski <dwysocha@redhat.com>

fs/nfs/dir.c

@@ -469,8 +469,20 @@ static int nfs_readdir_xdr_filler(struct nfs_readdir_descriptor *desc,
 				  u64 cookie, struct page **pages,
 				  size_t bufsize)
 {
-	struct file *file = desc->file;
-	struct inode *inode = file_inode(file);
+	struct inode *inode = file_inode(desc->file);
+	__be32 verf_res[2];
+	struct nfs_readdir_arg arg = {
+		.dentry = file_dentry(desc->file),
+		.cred = desc->file->f_cred,
+		.verf = NFS_I(inode)->cookieverf,
+		.cookie = cookie,
+		.pages = pages,
+		.page_len = bufsize,
+		.plus = desc->plus,
+	};
+	struct nfs_readdir_res res = {
+		.verf = verf_res,
+	};
 	unsigned long	timestamp, gencount;
 	int		error;
 
@@ -478,20 +490,21 @@ static int nfs_readdir_xdr_filler(struct nfs_readdir_descriptor *desc,
 	timestamp = jiffies;
 	gencount = nfs_inc_attr_generation_counter();
 	desc->dir_verifier = nfs_save_change_attribute(inode);
-	error = NFS_PROTO(inode)->readdir(file_dentry(file), file->f_cred,
-					  cookie, pages, bufsize, desc->plus);
+	error = NFS_PROTO(inode)->readdir(&arg, &res);
 	if (error < 0) {
 		/* We requested READDIRPLUS, but the server doesn't grok it */
 		if (error == -ENOTSUPP && desc->plus) {
 			NFS_SERVER(inode)->caps &= ~NFS_CAP_READDIRPLUS;
 			clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(inode)->flags);
-			desc->plus = false;
+			desc->plus = arg.plus = false;
 			goto again;
 		}
 		goto error;
 	}
 	desc->timestamp = timestamp;
 	desc->gencount = gencount;
+	memcpy(NFS_I(inode)->cookieverf, res.verf,
+	       sizeof(NFS_I(inode)->cookieverf));
 error:
 	return error;
 }

fs/nfs/nfs3proc.c

@@ -662,37 +662,36 @@ nfs3_proc_rmdir(struct inode *dir, const struct qstr *name)
  * Also note that this implementation handles both plain readdir and
  * readdirplus.
  */
-static int
-nfs3_proc_readdir(struct dentry *dentry, const struct cred *cred,
-		  u64 cookie, struct page **pages, unsigned int count, bool plus)
+static int nfs3_proc_readdir(struct nfs_readdir_arg *nr_arg,
+			     struct nfs_readdir_res *nr_res)
 {
-	struct inode		*dir = d_inode(dentry);
-	__be32			*verf = NFS_I(dir)->cookieverf;
+	struct inode		*dir = d_inode(nr_arg->dentry);
 	struct nfs3_readdirargs	arg = {
 		.fh		= NFS_FH(dir),
-		.cookie		= cookie,
-		.verf		= {verf[0], verf[1]},
-		.plus		= plus,
-		.count		= count,
-		.pages		= pages
+		.cookie		= nr_arg->cookie,
+		.plus		= nr_arg->plus,
+		.count		= nr_arg->page_len,
+		.pages		= nr_arg->pages
 	};
 	struct nfs3_readdirres	res = {
-		.verf		= verf,
-		.plus		= plus
+		.verf		= nr_res->verf,
+		.plus		= nr_arg->plus,
 	};
 	struct rpc_message	msg = {
 		.rpc_proc	= &nfs3_procedures[NFS3PROC_READDIR],
 		.rpc_argp	= &arg,
 		.rpc_resp	= &res,
-		.rpc_cred	= cred,
+		.rpc_cred	= nr_arg->cred,
 	};
 	int status = -ENOMEM;
 
-	if (plus)
+	if (nr_arg->plus)
 		msg.rpc_proc = &nfs3_procedures[NFS3PROC_READDIRPLUS];
+	if (arg.cookie)
+		memcpy(arg.verf, nr_arg->verf, sizeof(arg.verf));
 
-	dprintk("NFS call  readdir%s %d\n",
-			plus? "plus" : "", (unsigned int) cookie);
+	dprintk("NFS call  readdir%s %llu\n", nr_arg->plus ? "plus" : "",
+		(unsigned long long)nr_arg->cookie);
 
 	res.dir_attr = nfs_alloc_fattr();
 	if (res.dir_attr == NULL)
@@ -705,8 +704,8 @@ nfs3_proc_readdir(struct dentry *dentry, const struct cred *cred,
 
 	nfs_free_fattr(res.dir_attr);
 out:
-	dprintk("NFS reply readdir%s: %d\n",
-			plus? "plus" : "", status);
+	dprintk("NFS reply readdir%s: %d\n", nr_arg->plus ? "plus" : "",
+		status);
 	return status;
 }
 

fs/nfs/nfs4proc.c

@@ -4961,41 +4961,40 @@ static int nfs4_proc_mkdir(struct inode *dir, struct dentry *dentry,
 	return err;
 }
 
-static int _nfs4_proc_readdir(struct dentry *dentry, const struct cred *cred,
-		u64 cookie, struct page **pages, unsigned int count, bool plus)
+static int _nfs4_proc_readdir(struct nfs_readdir_arg *nr_arg,
+			      struct nfs_readdir_res *nr_res)
 {
-	struct inode		*dir = d_inode(dentry);
+	struct inode		*dir = d_inode(nr_arg->dentry);
 	struct nfs_server	*server = NFS_SERVER(dir);
 	struct nfs4_readdir_arg args = {
 		.fh = NFS_FH(dir),
-		.pages = pages,
+		.pages = nr_arg->pages,
 		.pgbase = 0,
-		.count = count,
-		.plus = plus,
+		.count = nr_arg->page_len,
+		.plus = nr_arg->plus,
 	};
 	struct nfs4_readdir_res res;
 	struct rpc_message msg = {
 		.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_READDIR],
 		.rpc_argp = &args,
 		.rpc_resp = &res,
-		.rpc_cred = cred,
+		.rpc_cred = nr_arg->cred,
 	};
 	int			status;
 
-	dprintk("%s: dentry = %pd2, cookie = %Lu\n", __func__,
-			dentry,
-			(unsigned long long)cookie);
+	dprintk("%s: dentry = %pd2, cookie = %llu\n", __func__,
+		nr_arg->dentry, (unsigned long long)nr_arg->cookie);
 	if (!(server->caps & NFS_CAP_SECURITY_LABEL))
 		args.bitmask = server->attr_bitmask_nl;
 	else
 		args.bitmask = server->attr_bitmask;
 
-	nfs4_setup_readdir(cookie, NFS_I(dir)->cookieverf, dentry, &args);
+	nfs4_setup_readdir(nr_arg->cookie, nr_arg->verf, nr_arg->dentry, &args);
 	res.pgbase = args.pgbase;
 	status = nfs4_call_sync(server->client, server, &msg, &args.seq_args,
 			&res.seq_res, 0);
 	if (status >= 0) {
-		memcpy(NFS_I(dir)->cookieverf, res.verifier.data, NFS4_VERIFIER_SIZE);
+		memcpy(nr_res->verf, res.verifier.data, NFS4_VERIFIER_SIZE);
 		status += args.pgbase;
 	}
 
@@ -5005,19 +5004,18 @@ static int _nfs4_proc_readdir(struct dentry *dentry, const struct cred *cred,
 	return status;
 }
 
-static int nfs4_proc_readdir(struct dentry *dentry, const struct cred *cred,
-		u64 cookie, struct page **pages, unsigned int count, bool plus)
+static int nfs4_proc_readdir(struct nfs_readdir_arg *arg,
+			     struct nfs_readdir_res *res)
 {
 	struct nfs4_exception exception = {
 		.interruptible = true,
 	};
 	int err;
 	do {
-		err = _nfs4_proc_readdir(dentry, cred, cookie,
-				pages, count, plus);
-		trace_nfs4_readdir(d_inode(dentry), err);
-		err = nfs4_handle_exception(NFS_SERVER(d_inode(dentry)), err,
-				&exception);
+		err = _nfs4_proc_readdir(arg, res);
+		trace_nfs4_readdir(d_inode(arg->dentry), err);
+		err = nfs4_handle_exception(NFS_SERVER(d_inode(arg->dentry)),
+					    err, &exception);
 	} while (exception.retry);
 	return err;
 }

fs/nfs/proc.c

@@ -499,26 +499,26 @@ nfs_proc_rmdir(struct inode *dir, const struct qstr *name)
  * sure it is syntactically correct; the entries itself are decoded
  * from nfs_readdir by calling the decode_entry function directly.
  */
-static int
-nfs_proc_readdir(struct dentry *dentry, const struct cred *cred,
-		 u64 cookie, struct page **pages, unsigned int count, bool plus)
+static int nfs_proc_readdir(struct nfs_readdir_arg *nr_arg,
+			    struct nfs_readdir_res *nr_res)
 {
-	struct inode		*dir = d_inode(dentry);
+	struct inode		*dir = d_inode(nr_arg->dentry);
 	struct nfs_readdirargs	arg = {
 		.fh		= NFS_FH(dir),
-		.cookie		= cookie,
-		.count		= count,
-		.pages		= pages,
+		.cookie		= nr_arg->cookie,
+		.count		= nr_arg->page_len,
+		.pages		= nr_arg->pages,
 	};
 	struct rpc_message	msg = {
 		.rpc_proc	= &nfs_procedures[NFSPROC_READDIR],
 		.rpc_argp	= &arg,
-		.rpc_cred	= cred,
+		.rpc_cred	= nr_arg->cred,
 	};
 	int			status;
 
-	dprintk("NFS call  readdir %d\n", (unsigned int)cookie);
+	dprintk("NFS call  readdir %llu\n", (unsigned long long)nr_arg->cookie);
 	status = rpc_call_sync(NFS_CLIENT(dir), &msg, 0);
+	nr_res->verf[0] = nr_res->verf[1] = 0;
 
 	nfs_invalidate_atime(dir);
 

include/linux/nfs_xdr.h

@@ -750,6 +750,20 @@ struct nfs_entry {
 	struct nfs_server *	server;
 };
 
+struct nfs_readdir_arg {
+	struct dentry		*dentry;
+	const struct cred	*cred;
+	__be32			*verf;
+	u64			cookie;
+	struct page		**pages;
+	unsigned int		page_len;
+	bool			plus;
+};
+
+struct nfs_readdir_res {
+	__be32			*verf;
+};
+
 /*
  * The following types are for NFSv2 only.
  */
@@ -1744,8 +1758,7 @@ struct nfs_rpc_ops {
 			    unsigned int, struct iattr *);
 	int	(*mkdir)   (struct inode *, struct dentry *, struct iattr *);
 	int	(*rmdir)   (struct inode *, const struct qstr *);
-	int	(*readdir) (struct dentry *, const struct cred *,
-			    u64, struct page **, unsigned int, bool);
+	int	(*readdir) (struct nfs_readdir_arg *, struct nfs_readdir_res *);
 	int	(*mknod)   (struct inode *, struct dentry *, struct iattr *,
 			    dev_t);
 	int	(*statfs)  (struct nfs_server *, struct nfs_fh *,