staging: add Lustre file system client support

Lustre is the most deployed distributed file system
in the HPC (High Performance Computing) world. The patch
adds its client side support.

The code is not very clean and needs to live in drivers/staging
for some time for continuing cleanup work. See
drivers/staging/lustre/TODO for details.

The code is based on Lustre master commit faefbfc04

commit faefbfc0460bc00f2ee4c1c1c86aa1e39b9eea49
Author: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Date:   Tue Apr 30 23:05:21 2013 +0400

    LU-3244 utils: tunefs.lustre should preserve virgin label

Plus a few under-review patches on Whamcloud gerrit:
3.8 kernel support:
http://review.whamcloud.com/#change,5973
http://review.whamcloud.com/#change,5974
http://review.whamcloud.com/#change,5768
http://review.whamcloud.com/#change,5781
http://review.whamcloud.com/#change,5763
http://review.whamcloud.com/#change,5613
http://review.whamcloud.com/#change,5655

3.9 kernel support:
http://review.whamcloud.com/#change,5898
http://review.whamcloud.com/#change,5899

Kconfig/Kbuild:
http://review.whamcloud.com/#change,4646
http://review.whamcloud.com/#change,4644

libcfs cleanup:
http://review.whamcloud.com/#change,2831
http://review.whamcloud.com/#change,4775
http://review.whamcloud.com/#change,4776
http://review.whamcloud.com/#change,4777
http://review.whamcloud.com/#change,4778
http://review.whamcloud.com/#change,4779
http://review.whamcloud.com/#change,4780

All starting/trailing whitespaces are removed, to match kernel
coding style. Also ran scripts/cleanfile on all lustre source files.

[maked the Kconfig depend on BROKEN as the recent procfs changes causes
this to fail - gregkh]

Signed-off-by: Peng Tao <tao.peng@emc.com>
Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 192 insertions, 0 deletions

diff --git a/drivers/staging/lustre/lustre/llite/symlink.c b/drivers/staging/lustre/lustre/llite/symlink.c
new file mode 100644
index 000000000000..5260e989a4e5
--- /dev/null
+++ b/drivers/staging/lustre/lustre/llite/symlink.c
@@ -0,0 +1,192 @@
+/*
+ * GPL HEADER START
+ *
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 only,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License version 2 for more details (a copy is included
+ * in the LICENSE file that accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License
+ * version 2 along with this program; If not, see
+ * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ * GPL HEADER END
+ */
+/*
+ * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Use is subject to license terms.
+ *
+ * Copyright (c) 2011, 2012, Intel Corporation.
+ */
+/*
+ * This file is part of Lustre, http://www.lustre.org/
+ * Lustre is a trademark of Sun Microsystems, Inc.
+ */
+
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/stat.h>
+#include <linux/version.h>
+#define DEBUG_SUBSYSTEM S_LLITE
+
+#include <lustre_lite.h>
+#include "llite_internal.h"
+
+static int ll_readlink_internal(struct inode *inode,
+				struct ptlrpc_request **request, char **symname)
+{
+	struct ll_inode_info *lli = ll_i2info(inode);
+	struct ll_sb_info *sbi = ll_i2sbi(inode);
+	int rc, symlen = i_size_read(inode) + 1;
+	struct mdt_body *body;
+	struct md_op_data *op_data;
+	ENTRY;
+
+	*request = NULL;
+
+	if (lli->lli_symlink_name) {
+		int print_limit = min_t(int, PAGE_SIZE - 128, symlen);
+
+		*symname = lli->lli_symlink_name;
+		/* If the total CDEBUG() size is larger than a page, it
+		 * will print a warning to the console, avoid this by
+		 * printing just the last part of the symlink. */
+		CDEBUG(D_INODE, "using cached symlink %s%.*s, len = %d\n",
+		       print_limit < symlen ? "..." : "", print_limit,
+		       (*symname) + symlen - print_limit, symlen);
+		RETURN(0);
+	}
+
+	op_data = ll_prep_md_op_data(NULL, inode, NULL, NULL, 0, symlen,
+				     LUSTRE_OPC_ANY, NULL);
+	if (IS_ERR(op_data))
+		RETURN(PTR_ERR(op_data));
+
+	op_data->op_valid = OBD_MD_LINKNAME;
+	rc = md_getattr(sbi->ll_md_exp, op_data, request);
+	ll_finish_md_op_data(op_data);
+	if (rc) {
+		if (rc != -ENOENT)
+			CERROR("inode %lu: rc = %d\n", inode->i_ino, rc);
+		GOTO (failed, rc);
+	}
+
+	body = req_capsule_server_get(&(*request)->rq_pill, &RMF_MDT_BODY);
+	LASSERT(body != NULL);
+	if ((body->valid & OBD_MD_LINKNAME) == 0) {
+		CERROR("OBD_MD_LINKNAME not set on reply\n");
+		GOTO(failed, rc = -EPROTO);
+	}
+
+	LASSERT(symlen != 0);
+	if (body->eadatasize != symlen) {
+		CERROR("inode %lu: symlink length %d not expected %d\n",
+			inode->i_ino, body->eadatasize - 1, symlen - 1);
+		GOTO(failed, rc = -EPROTO);
+	}
+
+	*symname = req_capsule_server_get(&(*request)->rq_pill, &RMF_MDT_MD);
+	if (*symname == NULL ||
+	    strnlen(*symname, symlen) != symlen - 1) {
+		/* not full/NULL terminated */
+		CERROR("inode %lu: symlink not NULL terminated string"
+			"of length %d\n", inode->i_ino, symlen - 1);
+		GOTO(failed, rc = -EPROTO);
+	}
+
+	OBD_ALLOC(lli->lli_symlink_name, symlen);
+	/* do not return an error if we cannot cache the symlink locally */
+	if (lli->lli_symlink_name) {
+		memcpy(lli->lli_symlink_name, *symname, symlen);
+		*symname = lli->lli_symlink_name;
+	}
+	RETURN(0);
+
+failed:
+	RETURN (rc);
+}
+
+static int ll_readlink(struct dentry *dentry, char *buffer, int buflen)
+{
+	struct inode *inode = dentry->d_inode;
+	struct ptlrpc_request *request;
+	char *symname;
+	int rc;
+	ENTRY;
+
+	CDEBUG(D_VFSTRACE, "VFS Op\n");
+
+	ll_inode_size_lock(inode);
+	rc = ll_readlink_internal(inode, &request, &symname);
+	if (rc)
+		GOTO(out, rc);
+
+	rc = vfs_readlink(dentry, buffer, buflen, symname);
+ out:
+	ptlrpc_req_finished(request);
+	ll_inode_size_unlock(inode);
+	RETURN(rc);
+}
+
+static void *ll_follow_link(struct dentry *dentry, struct nameidata *nd)
+{
+	struct inode *inode = dentry->d_inode;
+	struct ptlrpc_request *request = NULL;
+	int rc;
+	char *symname;
+	ENTRY;
+
+	CDEBUG(D_VFSTRACE, "VFS Op\n");
+	/* Limit the recursive symlink depth to 5 instead of default
+	 * 8 links when kernel has 4k stack to prevent stack overflow.
+	 * For 8k stacks we need to limit it to 7 for local servers. */
+	if (THREAD_SIZE < 8192 && current->link_count >= 6) {
+		rc = -ELOOP;
+	} else if (THREAD_SIZE == 8192 && current->link_count >= 8) {
+		rc = -ELOOP;
+	} else {
+		ll_inode_size_lock(inode);
+		rc = ll_readlink_internal(inode, &request, &symname);
+		ll_inode_size_unlock(inode);
+	}
+	if (rc) {
+		ptlrpc_req_finished(request);
+		request = NULL;
+		symname = ERR_PTR(rc);
+	}
+
+	nd_set_link(nd, symname);
+	/* symname may contain a pointer to the request message buffer,
+	 * we delay request releasing until ll_put_link then.
+	 */
+	RETURN(request);
+}
+
+static void ll_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie)
+{
+	ptlrpc_req_finished(cookie);
+}
+
+struct inode_operations ll_fast_symlink_inode_operations = {
+	.readlink	= ll_readlink,
+	.setattr	= ll_setattr,
+	.follow_link	= ll_follow_link,
+	.put_link	= ll_put_link,
+	.getattr	= ll_getattr,
+	.permission	= ll_inode_permission,
+	.setxattr	= ll_setxattr,
+	.getxattr	= ll_getxattr,
+	.listxattr	= ll_listxattr,
+	.removexattr	= ll_removexattr,
+};