sysfile.c

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/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * sysfile.c
 *
 * Initialize, read, write, etc. system files.
 *
 * Copyright (C) 2002, 2004 Oracle.  All rights reserved.
 *
 * 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.  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., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

#include <linux/fs.h>
#include <linux/types.h>
#include <linux/highmem.h>

#include <cluster/masklog.h>

#include "ocfs2.h"

#include "alloc.h"
#include "dir.h"
#include "inode.h"
#include "journal.h"
#include "sysfile.h"

#include "buffer_head_io.h"

static struct inode * _ocfs2_get_system_file_inode(struct ocfs2_super *osb,
                           int type,
                           u32 slot);

#ifdef CONFIG_DEBUG_LOCK_ALLOC
static struct lock_class_key ocfs2_sysfile_cluster_lock_key[NUM_SYSTEM_INODES];
#endif

static inline int is_global_system_inode(int type)
{
    return type >= OCFS2_FIRST_ONLINE_SYSTEM_INODE &&
        type <= OCFS2_LAST_GLOBAL_SYSTEM_INODE;
}

static struct inode **get_local_system_inode(struct ocfs2_super *osb,
                         int type,
                         u32 slot)
{
    int index;
    struct inode **local_system_inodes, **free = NULL;

    BUG_ON(slot == OCFS2_INVALID_SLOT);
    BUG_ON(type < OCFS2_FIRST_LOCAL_SYSTEM_INODE ||
           type > OCFS2_LAST_LOCAL_SYSTEM_INODE);

    spin_lock(&osb->osb_lock);
    local_system_inodes = osb->local_system_inodes;
    spin_unlock(&osb->osb_lock);

    if (unlikely(!local_system_inodes)) {
        local_system_inodes = kzalloc(sizeof(struct inode *) *
                          NUM_LOCAL_SYSTEM_INODES *
                          osb->max_slots,
                          GFP_NOFS);
        if (!local_system_inodes) {
            mlog_errno(-ENOMEM);
            /*
             * return NULL here so that ocfs2_get_sytem_file_inodes
             * will try to create an inode and use it. We will try
             * to initialize local_system_inodes next time.
             */
            return NULL;
        }

        spin_lock(&osb->osb_lock);
        if (osb->local_system_inodes) {
            /* Someone has initialized it for us. */
            free = local_system_inodes;
            local_system_inodes = osb->local_system_inodes;
        } else
            osb->local_system_inodes = local_system_inodes;
        spin_unlock(&osb->osb_lock);
        if (unlikely(free))
            kfree(free);
    }

    index = (slot * NUM_LOCAL_SYSTEM_INODES) +
        (type - OCFS2_FIRST_LOCAL_SYSTEM_INODE);

    return &local_system_inodes[index];
}

struct inode *ocfs2_get_system_file_inode(struct ocfs2_super *osb,
                      int type,
                      u32 slot)
{
    struct inode *inode = NULL;
    struct inode **arr = NULL;

    /* avoid the lookup if cached in local system file array */
    if (is_global_system_inode(type)) {
        arr = &(osb->global_system_inodes[type]);
    } else
        arr = get_local_system_inode(osb, type, slot);

    if (arr && ((inode = *arr) != NULL)) {
        /* get a ref in addition to the array ref */
        inode = igrab(inode);
        BUG_ON(!inode);

        return inode;
    }

    /* this gets one ref thru iget */
    inode = _ocfs2_get_system_file_inode(osb, type, slot);

    /* add one more if putting into array for first time */
    if (arr && inode) {
        *arr = igrab(inode);
        BUG_ON(!*arr);
    }
    return inode;
}

static struct inode * _ocfs2_get_system_file_inode(struct ocfs2_super *osb,
                           int type,
                           u32 slot)
{
    char namebuf[40];
    struct inode *inode = NULL;
    u64 blkno;
    int status = 0;

    ocfs2_sprintf_system_inode_name(namebuf,
                    sizeof(namebuf),
                    type, slot);

    status = ocfs2_lookup_ino_from_name(osb->sys_root_inode, namebuf,
                        strlen(namebuf), &blkno);
    if (status < 0) {
        goto bail;
    }

    inode = ocfs2_iget(osb, blkno, OCFS2_FI_FLAG_SYSFILE, type);
    if (IS_ERR(inode)) {
        mlog_errno(PTR_ERR(inode));
        inode = NULL;
        goto bail;
    }
#ifdef CONFIG_DEBUG_LOCK_ALLOC
    if (type == LOCAL_USER_QUOTA_SYSTEM_INODE ||
        type == LOCAL_GROUP_QUOTA_SYSTEM_INODE ||
        type == JOURNAL_SYSTEM_INODE) {
        /* Ignore inode lock on these inodes as the lock does not
         * really belong to any process and lockdep cannot handle
         * that */
        OCFS2_I(inode)->ip_inode_lockres.l_lockdep_map.key = NULL;
    } else {
        lockdep_init_map(&OCFS2_I(inode)->ip_inode_lockres.
                                l_lockdep_map,
                 ocfs2_system_inodes[type].si_name,
                 &ocfs2_sysfile_cluster_lock_key[type], 0);
    }
#endif
bail:

    return inode;
}