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