/*
 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
 * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
 *
 * This copyrighted material is made available to anyone wishing to use,
 * modify, copy, or redistribute it subject to the terms and conditions
 * of the GNU General Public License version 2.
 */

#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/kallsyms.h>
#include <linux/gfs2_ondisk.h>

#include "gfs2.h"
#include "incore.h"
#include "glock.h"
#include "inode.h"
#include "log.h"
#include "lops.h"
#include "meta_io.h"
#include "trans.h"
#include "util.h"
#include "trace_gfs2.h"

int gfs2_trans_begin(struct gfs2_sbd *sdp, unsigned int blocks,
                     unsigned int revokes)
{
        struct gfs2_trans *tr;
        int error;

        BUG_ON(current->journal_info);
        BUG_ON(blocks == 0 && revokes == 0);

        if (!test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags))
                return -EROFS;

        tr = kzalloc(sizeof(struct gfs2_trans), GFP_NOFS);
        if (!tr)
                return -ENOMEM;

        tr->tr_ip = (unsigned long)__builtin_return_address(0);
        tr->tr_blocks = blocks;
        tr->tr_revokes = revokes;
        tr->tr_reserved = 1;
        if (blocks)
                tr->tr_reserved += 6 + blocks;
        if (revokes)
                tr->tr_reserved += gfs2_struct2blk(sdp, revokes,
                                                   sizeof(u64));
        sb_start_intwrite(sdp->sd_vfs);
        gfs2_holder_init(sdp->sd_trans_gl, LM_ST_SHARED, 0, &tr->tr_t_gh);

        error = gfs2_glock_nq(&tr->tr_t_gh);
        if (error)
                goto fail_holder_uninit;

        error = gfs2_log_reserve(sdp, tr->tr_reserved);
        if (error)
                goto fail_gunlock;

        current->journal_info = tr;

        return 0;

fail_gunlock:
        gfs2_glock_dq(&tr->tr_t_gh);

fail_holder_uninit:
        sb_end_intwrite(sdp->sd_vfs);
        gfs2_holder_uninit(&tr->tr_t_gh);
        kfree(tr);

        return error;
}

/**
 * gfs2_log_release - Release a given number of log blocks
 * @sdp: The GFS2 superblock
 * @blks: The number of blocks
 *
 */

static void gfs2_log_release(struct gfs2_sbd *sdp, unsigned int blks)
{

        atomic_add(blks, &sdp->sd_log_blks_free);
        trace_gfs2_log_blocks(sdp, blks);
        gfs2_assert_withdraw(sdp, atomic_read(&sdp->sd_log_blks_free) <=
                                  sdp->sd_jdesc->jd_blocks);
        up_read(&sdp->sd_log_flush_lock);
}

static void gfs2_print_trans(const struct gfs2_trans *tr)
{
        printk(KERN_WARNING "GFS2: Transaction created at: %pSR\n",
               (void *)tr->tr_ip);
        printk(KERN_WARNING "GFS2: blocks=%u revokes=%u reserved=%u touched=%d\n",
               tr->tr_blocks, tr->tr_revokes, tr->tr_reserved, tr->tr_touched);
        printk(KERN_WARNING "GFS2: Buf %u/%u Databuf %u/%u Revoke %u/%u\n",
               tr->tr_num_buf_new, tr->tr_num_buf_rm,
               tr->tr_num_databuf_new, tr->tr_num_databuf_rm,
               tr->tr_num_revoke, tr->tr_num_revoke_rm);
}

void gfs2_trans_end(struct gfs2_sbd *sdp)
{
        struct gfs2_trans *tr = current->journal_info;
        s64 nbuf;
        BUG_ON(!tr);
        current->journal_info = NULL;

        if (!tr->tr_touched) {
                gfs2_log_release(sdp, tr->tr_reserved);
                if (tr->tr_t_gh.gh_gl) {
                        gfs2_glock_dq(&tr->tr_t_gh);
                        gfs2_holder_uninit(&tr->tr_t_gh);
                        kfree(tr);
                }
                sb_end_intwrite(sdp->sd_vfs);
                return;
        }

        nbuf = tr->tr_num_buf_new + tr->tr_num_databuf_new;
        nbuf -= tr->tr_num_buf_rm;
        nbuf -= tr->tr_num_databuf_rm;

        if (gfs2_assert_withdraw(sdp, (nbuf <= tr->tr_blocks) &&
                                       (tr->tr_num_revoke <= tr->tr_revokes)))
                gfs2_print_trans(tr);

        gfs2_log_commit(sdp, tr);
        if (tr->tr_t_gh.gh_gl) {
                gfs2_glock_dq(&tr->tr_t_gh);
                gfs2_holder_uninit(&tr->tr_t_gh);
                if (!tr->tr_attached)
                        kfree(tr);
        }
        up_read(&sdp->sd_log_flush_lock);

        if (sdp->sd_vfs->s_flags & MS_SYNCHRONOUS)
                gfs2_log_flush(sdp, NULL);
        sb_end_intwrite(sdp->sd_vfs);
}

static struct gfs2_bufdata *gfs2_alloc_bufdata(struct gfs2_glock *gl,
                                               struct buffer_head *bh,
                                               const struct gfs2_log_operations *lops)
{
        struct gfs2_bufdata *bd;

        bd = kmem_cache_zalloc(gfs2_bufdata_cachep, GFP_NOFS | __GFP_NOFAIL);
        bd->bd_bh = bh;
        bd->bd_gl = gl;
        bd->bd_ops = lops;
        INIT_LIST_HEAD(&bd->bd_list);
        bh->b_private = bd;
        return bd;
}

/**
 * gfs2_trans_add_data - Add a databuf to the transaction.
 * @gl: The inode glock associated with the buffer
 * @bh: The buffer to add
 *
 * This is used in two distinct cases:
 * i) In ordered write mode
 *    We put the data buffer on a list so that we can ensure that its
 *    synced to disk at the right time
 * ii) In journaled data mode
 *    We need to journal the data block in the same way as metadata in
 *    the functions above. The difference is that here we have a tag
 *    which is two __be64's being the block number (as per meta data)
 *    and a flag which says whether the data block needs escaping or
 *    not. This means we need a new log entry for each 251 or so data
 *    blocks, which isn't an enormous overhead but twice as much as
 *    for normal metadata blocks.
 */
void gfs2_trans_add_data(struct gfs2_glock *gl, struct buffer_head *bh)
{
        struct gfs2_trans *tr = current->journal_info;
        struct gfs2_sbd *sdp = gl->gl_sbd;
        struct address_space *mapping = bh->b_page->mapping;
        struct gfs2_inode *ip = GFS2_I(mapping->host);
        struct gfs2_bufdata *bd;

        if (!gfs2_is_jdata(ip)) {
                gfs2_ordered_add_inode(ip);
                return;
        }

        lock_buffer(bh);
        gfs2_log_lock(sdp);
        bd = bh->b_private;
        if (bd == NULL) {
                gfs2_log_unlock(sdp);
                unlock_buffer(bh);
                if (bh->b_private == NULL)
                        bd = gfs2_alloc_bufdata(gl, bh, &gfs2_databuf_lops);
                lock_buffer(bh);
                gfs2_log_lock(sdp);
        }
        gfs2_assert(sdp, bd->bd_gl == gl);
        tr->tr_touched = 1;
        if (list_empty(&bd->bd_list)) {
                set_bit(GLF_LFLUSH, &bd->bd_gl->gl_flags);
                set_bit(GLF_DIRTY, &bd->bd_gl->gl_flags);
                gfs2_pin(sdp, bd->bd_bh);
                tr->tr_num_databuf_new++;
                sdp->sd_log_num_databuf++;
                list_add_tail(&bd->bd_list, &sdp->sd_log_le_databuf);
        }
        gfs2_log_unlock(sdp);
        unlock_buffer(bh);
}

static void meta_lo_add(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd)
{
        struct gfs2_meta_header *mh;
        struct gfs2_trans *tr;

        tr = current->journal_info;
        tr->tr_touched = 1;
        if (!list_empty(&bd->bd_list))
                return;
        set_bit(GLF_LFLUSH, &bd->bd_gl->gl_flags);
        set_bit(GLF_DIRTY, &bd->bd_gl->gl_flags);
        mh = (struct gfs2_meta_header *)bd->bd_bh->b_data;
        if (unlikely(mh->mh_magic != cpu_to_be32(GFS2_MAGIC))) {
                printk(KERN_ERR
                       "Attempting to add uninitialised block to journal (inplace block=%lld)\n",
                       (unsigned long long)bd->bd_bh->b_blocknr);
                BUG();
        }
        gfs2_pin(sdp, bd->bd_bh);
        mh->__pad0 = cpu_to_be64(0);
        mh->mh_jid = cpu_to_be32(sdp->sd_jdesc->jd_jid);
        sdp->sd_log_num_buf++;
        list_add(&bd->bd_list, &sdp->sd_log_le_buf);
        tr->tr_num_buf_new++;
}

void gfs2_trans_add_meta(struct gfs2_glock *gl, struct buffer_head *bh)
{

        struct gfs2_sbd *sdp = gl->gl_sbd;
        struct gfs2_bufdata *bd;

        lock_buffer(bh);
        gfs2_log_lock(sdp);
        bd = bh->b_private;
        if (bd == NULL) {
                gfs2_log_unlock(sdp);
                unlock_buffer(bh);
                lock_page(bh->b_page);
                if (bh->b_private == NULL)
                        bd = gfs2_alloc_bufdata(gl, bh, &gfs2_buf_lops);
                unlock_page(bh->b_page);
                lock_buffer(bh);
                gfs2_log_lock(sdp);
        }
        gfs2_assert(sdp, bd->bd_gl == gl);
        meta_lo_add(sdp, bd);
        gfs2_log_unlock(sdp);
        unlock_buffer(bh);
}

void gfs2_trans_add_revoke(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd)
{
        struct gfs2_trans *tr = current->journal_info;

        BUG_ON(!list_empty(&bd->bd_list));
        gfs2_add_revoke(sdp, bd);
        tr->tr_touched = 1;
        tr->tr_num_revoke++;
}

void gfs2_trans_add_unrevoke(struct gfs2_sbd *sdp, u64 blkno, unsigned int len)
{
        struct gfs2_bufdata *bd, *tmp;
        struct gfs2_trans *tr = current->journal_info;
        unsigned int n = len;

        gfs2_log_lock(sdp);
        list_for_each_entry_safe(bd, tmp, &sdp->sd_log_le_revoke, bd_list) {
                if ((bd->bd_blkno >= blkno) && (bd->bd_blkno < (blkno + len))) {
                        list_del_init(&bd->bd_list);
                        gfs2_assert_withdraw(sdp, sdp->sd_log_num_revoke);
                        sdp->sd_log_num_revoke--;
                        kmem_cache_free(gfs2_bufdata_cachep, bd);
                        tr->tr_num_revoke_rm++;
                        if (--n == 0)
                                break;
                }
        }
        gfs2_log_unlock(sdp);
}