root/fs/ocfs2/symlink.c

DEFINITIONS

1. ocfs2_page_getlink
2. ocfs2_fast_symlink_getlink
3. ocfs2_readlink
4. ocfs2_follow_link

/* -*- 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 "xattr.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;
        *ppage = page;
        return kmap(page);

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(inode, OCFS2_I(inode)->ip_blkno, bh);
        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);
        }
        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,
        .setattr        = ocfs2_setattr,
        .setxattr       = generic_setxattr,
        .getxattr       = generic_getxattr,
        .listxattr      = ocfs2_listxattr,
        .removexattr    = generic_removexattr,
};
const struct inode_operations ocfs2_fast_symlink_inode_operations = {
        .readlink       = ocfs2_readlink,
        .follow_link    = ocfs2_follow_link,
        .getattr        = ocfs2_getattr,
        .setattr        = ocfs2_setattr,
        .setxattr       = generic_setxattr,
        .getxattr       = generic_getxattr,
        .listxattr      = ocfs2_listxattr,
        .removexattr    = generic_removexattr,
};