kernel-ark/fs/ocfs2/symlink.c
Arjan van de Ven 92e1d5be91 [PATCH] mark struct inode_operations const 2
Many struct inode_operations in the kernel can be "const".  Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data.  In addition it'll catch accidental writes at compile time to
these shared resources.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 09:48:46 -08:00

183 lines
4.1 KiB
C

/* -*- mode: c; c-basic-offset: 8; -*-
* vim: noexpandtab sw=8 ts=8 sts=0:
*
* linux/cluster/ssi/cfs/symlink.c
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* 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, GOOD TITLE
* or NON INFRINGEMENT. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* Questions/Comments/Bugfixes to ssic-linux-devel@lists.sourceforge.net
*
* Copyright (C) 1992 Rick Sladkey
*
* Optimization changes Copyright (C) 1994 Florian La Roche
*
* Jun 7 1999, cache symlink lookups in the page cache. -DaveM
*
* Portions Copyright (C) 2001 Compaq Computer Corporation
*
* ocfs2 symlink handling code.
*
* Copyright (C) 2004, 2005 Oracle.
*
*/
#include <linux/fs.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/pagemap.h>
#include <linux/utsname.h>
#define MLOG_MASK_PREFIX ML_NAMEI
#include <cluster/masklog.h>
#include "ocfs2.h"
#include "alloc.h"
#include "file.h"
#include "inode.h"
#include "journal.h"
#include "symlink.h"
#include "buffer_head_io.h"
static char *ocfs2_page_getlink(struct dentry * dentry,
struct page **ppage);
static char *ocfs2_fast_symlink_getlink(struct inode *inode,
struct buffer_head **bh);
/* get the link contents into pagecache */
static char *ocfs2_page_getlink(struct dentry * dentry,
struct page **ppage)
{
struct page * page;
struct address_space *mapping = dentry->d_inode->i_mapping;
page = read_mapping_page(mapping, 0, NULL);
if (IS_ERR(page))
goto sync_fail;
wait_on_page_locked(page);
if (!PageUptodate(page))
goto async_fail;
*ppage = page;
return kmap(page);
async_fail:
page_cache_release(page);
return ERR_PTR(-EIO);
sync_fail:
return (char*)page;
}
static char *ocfs2_fast_symlink_getlink(struct inode *inode,
struct buffer_head **bh)
{
int status;
char *link = NULL;
struct ocfs2_dinode *fe;
mlog_entry_void();
status = ocfs2_read_block(OCFS2_SB(inode->i_sb),
OCFS2_I(inode)->ip_blkno,
bh,
OCFS2_BH_CACHED,
inode);
if (status < 0) {
mlog_errno(status);
link = ERR_PTR(status);
goto bail;
}
fe = (struct ocfs2_dinode *) (*bh)->b_data;
link = (char *) fe->id2.i_symlink;
bail:
mlog_exit(status);
return link;
}
static int ocfs2_readlink(struct dentry *dentry,
char __user *buffer,
int buflen)
{
int ret;
char *link;
struct buffer_head *bh = NULL;
struct inode *inode = dentry->d_inode;
mlog_entry_void();
link = ocfs2_fast_symlink_getlink(inode, &bh);
if (IS_ERR(link)) {
ret = PTR_ERR(link);
goto out;
}
/*
* Without vfsmount we can't update atime now,
* but we will update atime here ultimately.
*/
ret = vfs_readlink(dentry, buffer, buflen, link);
brelse(bh);
out:
mlog_exit(ret);
return ret;
}
static void *ocfs2_follow_link(struct dentry *dentry,
struct nameidata *nd)
{
int status;
char *link;
struct inode *inode = dentry->d_inode;
struct page *page = NULL;
struct buffer_head *bh = NULL;
if (ocfs2_inode_is_fast_symlink(inode))
link = ocfs2_fast_symlink_getlink(inode, &bh);
else
link = ocfs2_page_getlink(dentry, &page);
if (IS_ERR(link)) {
status = PTR_ERR(link);
mlog_errno(status);
goto bail;
}
status = vfs_follow_link(nd, link);
bail:
if (page) {
kunmap(page);
page_cache_release(page);
}
if (bh)
brelse(bh);
return ERR_PTR(status);
}
const struct inode_operations ocfs2_symlink_inode_operations = {
.readlink = page_readlink,
.follow_link = ocfs2_follow_link,
.getattr = ocfs2_getattr,
};
const struct inode_operations ocfs2_fast_symlink_inode_operations = {
.readlink = ocfs2_readlink,
.follow_link = ocfs2_follow_link,
.getattr = ocfs2_getattr,
};