--- /dev/null
+/*
+ * 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>
+#define DEBUG_SUBSYSTEM S_LLITE
+
+#include "../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;
+
+ *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;
+ }
+
+ 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");
+ rc = -EPROTO;
+ goto failed;
+ }
+
+ 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);
+ rc = -EPROTO;
+ goto failed;
+ }
+
+ *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);
+ rc = -EPROTO;
+ goto failed;
+ }
+
+ lli->lli_symlink_name = kzalloc(symlen, GFP_NOFS);
+ /* 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 void *ll_follow_link(struct dentry *dentry, struct nameidata *nd)
+{
+ struct inode *inode = d_inode(dentry);
+ struct ptlrpc_request *request = NULL;
+ int rc;
+ char *symname = NULL;
+
+ 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 = generic_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,
+};
Code Review / kvmfornfv.git / blobdiff