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/*
* 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 <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, 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;
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;
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,
};
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