slot_map.c

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/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * slot_map.c
 *
 *
 *
 * 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/types.h>
#include <linux/slab.h>
#include <linux/highmem.h>

#include <cluster/masklog.h>

#include "ocfs2.h"

#include "dlmglue.h"
#include "extent_map.h"
#include "heartbeat.h"
#include "inode.h"
#include "slot_map.h"
#include "super.h"
#include "sysfile.h"
#include "ocfs2_trace.h"

#include "buffer_head_io.h"


struct ocfs2_slot {
    int sl_valid;
    unsigned int sl_node_num;
};

struct ocfs2_slot_info {
    int si_extended;
    int si_slots_per_block;
    struct inode *si_inode;
    unsigned int si_blocks;
    struct buffer_head **si_bh;
    unsigned int si_num_slots;
    struct ocfs2_slot *si_slots;
};


static int __ocfs2_node_num_to_slot(struct ocfs2_slot_info *si,
                    unsigned int node_num);

static void ocfs2_invalidate_slot(struct ocfs2_slot_info *si,
                  int slot_num)
{
    BUG_ON((slot_num < 0) || (slot_num >= si->si_num_slots));
    si->si_slots[slot_num].sl_valid = 0;
}

static void ocfs2_set_slot(struct ocfs2_slot_info *si,
               int slot_num, unsigned int node_num)
{
    BUG_ON((slot_num < 0) || (slot_num >= si->si_num_slots));

    si->si_slots[slot_num].sl_valid = 1;
    si->si_slots[slot_num].sl_node_num = node_num;
}

/* This version is for the extended slot map */
static void ocfs2_update_slot_info_extended(struct ocfs2_slot_info *si)
{
    int b, i, slotno;
    struct ocfs2_slot_map_extended *se;

    slotno = 0;
    for (b = 0; b < si->si_blocks; b++) {
        se = (struct ocfs2_slot_map_extended *)si->si_bh[b]->b_data;
        for (i = 0;
             (i < si->si_slots_per_block) &&
             (slotno < si->si_num_slots);
             i++, slotno++) {
            if (se->se_slots[i].es_valid)
                ocfs2_set_slot(si, slotno,
                           le32_to_cpu(se->se_slots[i].es_node_num));
            else
                ocfs2_invalidate_slot(si, slotno);
        }
    }
}

/*
 * Post the slot information on disk into our slot_info struct.
 * Must be protected by osb_lock.
 */
static void ocfs2_update_slot_info_old(struct ocfs2_slot_info *si)
{
    int i;
    struct ocfs2_slot_map *sm;

    sm = (struct ocfs2_slot_map *)si->si_bh[0]->b_data;

    for (i = 0; i < si->si_num_slots; i++) {
        if (le16_to_cpu(sm->sm_slots[i]) == (u16)OCFS2_INVALID_SLOT)
            ocfs2_invalidate_slot(si, i);
        else
            ocfs2_set_slot(si, i, le16_to_cpu(sm->sm_slots[i]));
    }
}

static void ocfs2_update_slot_info(struct ocfs2_slot_info *si)
{
    /*
     * The slot data will have been refreshed when ocfs2_super_lock
     * was taken.
     */
    if (si->si_extended)
        ocfs2_update_slot_info_extended(si);
    else
        ocfs2_update_slot_info_old(si);
}

int ocfs2_refresh_slot_info(struct ocfs2_super *osb)
{
    int ret;
    struct ocfs2_slot_info *si = osb->slot_info;

    if (si == NULL)
        return 0;

    BUG_ON(si->si_blocks == 0);
    BUG_ON(si->si_bh == NULL);

    trace_ocfs2_refresh_slot_info(si->si_blocks);

    /*
     * We pass -1 as blocknr because we expect all of si->si_bh to
     * be !NULL.  Thus, ocfs2_read_blocks() will ignore blocknr.  If
     * this is not true, the read of -1 (UINT64_MAX) will fail.
     */
    ret = ocfs2_read_blocks(INODE_CACHE(si->si_inode), -1, si->si_blocks,
                si->si_bh, OCFS2_BH_IGNORE_CACHE, NULL);
    if (ret == 0) {
        spin_lock(&osb->osb_lock);
        ocfs2_update_slot_info(si);
        spin_unlock(&osb->osb_lock);
    }

    return ret;
}

/* post the our slot info stuff into it's destination bh and write it
 * out. */
static void ocfs2_update_disk_slot_extended(struct ocfs2_slot_info *si,
                        int slot_num,
                        struct buffer_head **bh)
{
    int blkind = slot_num / si->si_slots_per_block;
    int slotno = slot_num % si->si_slots_per_block;
    struct ocfs2_slot_map_extended *se;

    BUG_ON(blkind >= si->si_blocks);

    se = (struct ocfs2_slot_map_extended *)si->si_bh[blkind]->b_data;
    se->se_slots[slotno].es_valid = si->si_slots[slot_num].sl_valid;
    if (si->si_slots[slot_num].sl_valid)
        se->se_slots[slotno].es_node_num =
            cpu_to_le32(si->si_slots[slot_num].sl_node_num);
    *bh = si->si_bh[blkind];
}

static void ocfs2_update_disk_slot_old(struct ocfs2_slot_info *si,
                       int slot_num,
                       struct buffer_head **bh)
{
    int i;
    struct ocfs2_slot_map *sm;

    sm = (struct ocfs2_slot_map *)si->si_bh[0]->b_data;
    for (i = 0; i < si->si_num_slots; i++) {
        if (si->si_slots[i].sl_valid)
            sm->sm_slots[i] =
                cpu_to_le16(si->si_slots[i].sl_node_num);
        else
            sm->sm_slots[i] = cpu_to_le16(OCFS2_INVALID_SLOT);
    }
    *bh = si->si_bh[0];
}

static int ocfs2_update_disk_slot(struct ocfs2_super *osb,
                  struct ocfs2_slot_info *si,
                  int slot_num)
{
    int status;
    struct buffer_head *bh;

    spin_lock(&osb->osb_lock);
    if (si->si_extended)
        ocfs2_update_disk_slot_extended(si, slot_num, &bh);
    else
        ocfs2_update_disk_slot_old(si, slot_num, &bh);
    spin_unlock(&osb->osb_lock);

    status = ocfs2_write_block(osb, bh, INODE_CACHE(si->si_inode));
    if (status < 0)
        mlog_errno(status);

    return status;
}

/*
 * Calculate how many bytes are needed by the slot map.  Returns
 * an error if the slot map file is too small.
 */
static int ocfs2_slot_map_physical_size(struct ocfs2_super *osb,
                    struct inode *inode,
                    unsigned long long *bytes)
{
    unsigned long long bytes_needed;

    if (ocfs2_uses_extended_slot_map(osb)) {
        bytes_needed = osb->max_slots *
            sizeof(struct ocfs2_extended_slot);
    } else {
        bytes_needed = osb->max_slots * sizeof(__le16);
    }
    if (bytes_needed > i_size_read(inode)) {
        mlog(ML_ERROR,
             "Slot map file is too small!  (size %llu, needed %llu)\n",
             i_size_read(inode), bytes_needed);
        return -ENOSPC;
    }

    *bytes = bytes_needed;
    return 0;
}

/* try to find global node in the slot info. Returns -ENOENT
 * if nothing is found. */
static int __ocfs2_node_num_to_slot(struct ocfs2_slot_info *si,
                    unsigned int node_num)
{
    int i, ret = -ENOENT;

    for(i = 0; i < si->si_num_slots; i++) {
        if (si->si_slots[i].sl_valid &&
            (node_num == si->si_slots[i].sl_node_num)) {
            ret = i;
            break;
        }
    }

    return ret;
}

static int __ocfs2_find_empty_slot(struct ocfs2_slot_info *si,
                   int preferred)
{
    int i, ret = -ENOSPC;

    if ((preferred >= 0) && (preferred < si->si_num_slots)) {
        if (!si->si_slots[preferred].sl_valid) {
            ret = preferred;
            goto out;
        }
    }

    for(i = 0; i < si->si_num_slots; i++) {
        if (!si->si_slots[i].sl_valid) {
            ret = i;
            break;
        }
    }
out:
    return ret;
}

int ocfs2_node_num_to_slot(struct ocfs2_super *osb, unsigned int node_num)
{
    int slot;
    struct ocfs2_slot_info *si = osb->slot_info;

    spin_lock(&osb->osb_lock);
    slot = __ocfs2_node_num_to_slot(si, node_num);
    spin_unlock(&osb->osb_lock);

    return slot;
}

int ocfs2_slot_to_node_num_locked(struct ocfs2_super *osb, int slot_num,
                  unsigned int *node_num)
{
    struct ocfs2_slot_info *si = osb->slot_info;

    assert_spin_locked(&osb->osb_lock);

    BUG_ON(slot_num < 0);
    BUG_ON(slot_num > osb->max_slots);

    if (!si->si_slots[slot_num].sl_valid)
        return -ENOENT;

    *node_num = si->si_slots[slot_num].sl_node_num;
    return 0;
}

static void __ocfs2_free_slot_info(struct ocfs2_slot_info *si)
{
    unsigned int i;

    if (si == NULL)
        return;

    if (si->si_inode)
        iput(si->si_inode);
    if (si->si_bh) {
        for (i = 0; i < si->si_blocks; i++) {
            if (si->si_bh[i]) {
                brelse(si->si_bh[i]);
                si->si_bh[i] = NULL;
            }
        }
        kfree(si->si_bh);
    }

    kfree(si);
}

int ocfs2_clear_slot(struct ocfs2_super *osb, int slot_num)
{
    struct ocfs2_slot_info *si = osb->slot_info;

    if (si == NULL)
        return 0;

    spin_lock(&osb->osb_lock);
    ocfs2_invalidate_slot(si, slot_num);
    spin_unlock(&osb->osb_lock);

    return ocfs2_update_disk_slot(osb, osb->slot_info, slot_num);
}

static int ocfs2_map_slot_buffers(struct ocfs2_super *osb,
                  struct ocfs2_slot_info *si)
{
    int status = 0;
    u64 blkno;
    unsigned long long blocks, bytes = 0;
    unsigned int i;
    struct buffer_head *bh;

    status = ocfs2_slot_map_physical_size(osb, si->si_inode, &bytes);
    if (status)
        goto bail;

    blocks = ocfs2_blocks_for_bytes(si->si_inode->i_sb, bytes);
    BUG_ON(blocks > UINT_MAX);
    si->si_blocks = blocks;
    if (!si->si_blocks)
        goto bail;

    if (si->si_extended)
        si->si_slots_per_block =
            (osb->sb->s_blocksize /
             sizeof(struct ocfs2_extended_slot));
    else
        si->si_slots_per_block = osb->sb->s_blocksize / sizeof(__le16);

    /* The size checks above should ensure this */
    BUG_ON((osb->max_slots / si->si_slots_per_block) > blocks);

    trace_ocfs2_map_slot_buffers(bytes, si->si_blocks);

    si->si_bh = kzalloc(sizeof(struct buffer_head *) * si->si_blocks,
                GFP_KERNEL);
    if (!si->si_bh) {
        status = -ENOMEM;
        mlog_errno(status);
        goto bail;
    }

    for (i = 0; i < si->si_blocks; i++) {
        status = ocfs2_extent_map_get_blocks(si->si_inode, i,
                             &blkno, NULL, NULL);
        if (status < 0) {
            mlog_errno(status);
            goto bail;
        }

        trace_ocfs2_map_slot_buffers_block((unsigned long long)blkno, i);

        bh = NULL;  /* Acquire a fresh bh */
        status = ocfs2_read_blocks(INODE_CACHE(si->si_inode), blkno,
                       1, &bh, OCFS2_BH_IGNORE_CACHE, NULL);
        if (status < 0) {
            mlog_errno(status);
            goto bail;
        }

        si->si_bh[i] = bh;
    }

bail:
    return status;
}

int ocfs2_init_slot_info(struct ocfs2_super *osb)
{
    int status;
    struct inode *inode = NULL;
    struct ocfs2_slot_info *si;

    si = kzalloc(sizeof(struct ocfs2_slot_info) +
             (sizeof(struct ocfs2_slot) * osb->max_slots),
             GFP_KERNEL);
    if (!si) {
        status = -ENOMEM;
        mlog_errno(status);
        goto bail;
    }

    si->si_extended = ocfs2_uses_extended_slot_map(osb);
    si->si_num_slots = osb->max_slots;
    si->si_slots = (struct ocfs2_slot *)((char *)si +
                         sizeof(struct ocfs2_slot_info));

    inode = ocfs2_get_system_file_inode(osb, SLOT_MAP_SYSTEM_INODE,
                        OCFS2_INVALID_SLOT);
    if (!inode) {
        status = -EINVAL;
        mlog_errno(status);
        goto bail;
    }

    si->si_inode = inode;
    status = ocfs2_map_slot_buffers(osb, si);
    if (status < 0) {
        mlog_errno(status);
        goto bail;
    }

    osb->slot_info = (struct ocfs2_slot_info *)si;
bail:
    if (status < 0 && si)
        __ocfs2_free_slot_info(si);

    return status;
}

void ocfs2_free_slot_info(struct ocfs2_super *osb)
{
    struct ocfs2_slot_info *si = osb->slot_info;

    osb->slot_info = NULL;
    __ocfs2_free_slot_info(si);
}

int ocfs2_find_slot(struct ocfs2_super *osb)
{
    int status;
    int slot;
    struct ocfs2_slot_info *si;

    si = osb->slot_info;

    spin_lock(&osb->osb_lock);
    ocfs2_update_slot_info(si);

    /* search for ourselves first and take the slot if it already
     * exists. Perhaps we need to mark this in a variable for our
     * own journal recovery? Possibly not, though we certainly
     * need to warn to the user */
    slot = __ocfs2_node_num_to_slot(si, osb->node_num);
    if (slot < 0) {
        /* if no slot yet, then just take 1st available
         * one. */
        slot = __ocfs2_find_empty_slot(si, osb->preferred_slot);
        if (slot < 0) {
            spin_unlock(&osb->osb_lock);
            mlog(ML_ERROR, "no free slots available!\n");
            status = -EINVAL;
            goto bail;
        }
    } else
        printk(KERN_INFO "ocfs2: Slot %d on device (%s) was already "
               "allocated to this node!\n", slot, osb->dev_str);

    ocfs2_set_slot(si, slot, osb->node_num);
    osb->slot_num = slot;
    spin_unlock(&osb->osb_lock);

    trace_ocfs2_find_slot(osb->slot_num);

    status = ocfs2_update_disk_slot(osb, si, osb->slot_num);
    if (status < 0)
        mlog_errno(status);

bail:
    return status;
}

void ocfs2_put_slot(struct ocfs2_super *osb)
{
    int status, slot_num;
    struct ocfs2_slot_info *si = osb->slot_info;

    if (!si)
        return;

    spin_lock(&osb->osb_lock);
    ocfs2_update_slot_info(si);

    slot_num = osb->slot_num;
    ocfs2_invalidate_slot(si, osb->slot_num);
    osb->slot_num = OCFS2_INVALID_SLOT;
    spin_unlock(&osb->osb_lock);

    status = ocfs2_update_disk_slot(osb, si, slot_num);
    if (status < 0) {
        mlog_errno(status);
        goto bail;
    }

bail:
    ocfs2_free_slot_info(osb);
}