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/* -*- 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;

        *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(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,

};