[SCSI] libsas: fix false positive 'device attached' conditions

[linux-2.6.git] / fs / gfs2 / lops.c

/*
 * 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/mempool.h>
#include <linux/gfs2_ondisk.h>
#include <linux/bio.h>
#include <linux/fs.h>

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

/**
 * gfs2_pin - Pin a buffer in memory
 * @sdp: The superblock
 * @bh: The buffer to be pinned
 *
 * The log lock must be held when calling this function
 */
static void gfs2_pin(struct gfs2_sbd *sdp, struct buffer_head *bh)
{
        struct gfs2_bufdata *bd;

        BUG_ON(!current->journal_info);

        clear_buffer_dirty(bh);
        if (test_set_buffer_pinned(bh))
                gfs2_assert_withdraw(sdp, 0);
        if (!buffer_uptodate(bh))
                gfs2_io_error_bh(sdp, bh);
        bd = bh->b_private;
        /* If this buffer is in the AIL and it has already been written
         * to in-place disk block, remove it from the AIL.
         */
        spin_lock(&sdp->sd_ail_lock);
        if (bd->bd_ail)
                list_move(&bd->bd_ail_st_list, &bd->bd_ail->ai_ail2_list);
        spin_unlock(&sdp->sd_ail_lock);
        get_bh(bh);
        atomic_inc(&sdp->sd_log_pinned);
        trace_gfs2_pin(bd, 1);
}

static bool buffer_is_rgrp(const struct gfs2_bufdata *bd)
{
        return bd->bd_gl->gl_name.ln_type == LM_TYPE_RGRP;
}

static void maybe_release_space(struct gfs2_bufdata *bd)
{
        struct gfs2_glock *gl = bd->bd_gl;
        struct gfs2_sbd *sdp = gl->gl_sbd;
        struct gfs2_rgrpd *rgd = gl->gl_object;
        unsigned int index = bd->bd_bh->b_blocknr - gl->gl_name.ln_number;
        struct gfs2_bitmap *bi = rgd->rd_bits + index;

        if (bi->bi_clone == 0)
                return;
        if (sdp->sd_args.ar_discard)
                gfs2_rgrp_send_discards(sdp, rgd->rd_data0, bd->bd_bh, bi, 1, NULL);
        memcpy(bi->bi_clone + bi->bi_offset,
               bd->bd_bh->b_data + bi->bi_offset, bi->bi_len);
        clear_bit(GBF_FULL, &bi->bi_flags);
        rgd->rd_free_clone = rgd->rd_free;
}

/**
 * gfs2_unpin - Unpin a buffer
 * @sdp: the filesystem the buffer belongs to
 * @bh: The buffer to unpin
 * @ai:
 * @flags: The inode dirty flags
 *
 */

static void gfs2_unpin(struct gfs2_sbd *sdp, struct buffer_head *bh,
                       struct gfs2_ail *ai)
{
        struct gfs2_bufdata *bd = bh->b_private;

        BUG_ON(!buffer_uptodate(bh));
        BUG_ON(!buffer_pinned(bh));

        lock_buffer(bh);
        mark_buffer_dirty(bh);
        clear_buffer_pinned(bh);

        if (buffer_is_rgrp(bd))
                maybe_release_space(bd);

        spin_lock(&sdp->sd_ail_lock);
        if (bd->bd_ail) {
                list_del(&bd->bd_ail_st_list);
                brelse(bh);
        } else {
                struct gfs2_glock *gl = bd->bd_gl;
                list_add(&bd->bd_ail_gl_list, &gl->gl_ail_list);
                atomic_inc(&gl->gl_ail_count);
        }
        bd->bd_ail = ai;
        list_add(&bd->bd_ail_st_list, &ai->ai_ail1_list);
        spin_unlock(&sdp->sd_ail_lock);

        clear_bit(GLF_LFLUSH, &bd->bd_gl->gl_flags);
        trace_gfs2_pin(bd, 0);
        unlock_buffer(bh);
        atomic_dec(&sdp->sd_log_pinned);
}


static inline struct gfs2_log_descriptor *bh_log_desc(struct buffer_head *bh)
{
        return (struct gfs2_log_descriptor *)bh->b_data;
}

static inline __be64 *bh_log_ptr(struct buffer_head *bh)
{
        struct gfs2_log_descriptor *ld = bh_log_desc(bh);
        return (__force __be64 *)(ld + 1);
}

static inline __be64 *bh_ptr_end(struct buffer_head *bh)
{
        return (__force __be64 *)(bh->b_data + bh->b_size);
}

/**
 * gfs2_log_write_endio - End of I/O for a log buffer
 * @bh: The buffer head
 * @uptodate: I/O Status
 *
 */

static void gfs2_log_write_endio(struct buffer_head *bh, int uptodate)
{
        struct gfs2_sbd *sdp = bh->b_private;
        bh->b_private = NULL;

        end_buffer_write_sync(bh, uptodate);
        if (atomic_dec_and_test(&sdp->sd_log_in_flight))
                wake_up(&sdp->sd_log_flush_wait);
}

/**
 * gfs2_log_get_buf - Get and initialize a buffer to use for log control data
 * @sdp: The GFS2 superblock
 *
 * tReturns: the buffer_head
 */

static struct buffer_head *gfs2_log_get_buf(struct gfs2_sbd *sdp)
{
        u64 blkno = gfs2_log_bmap(sdp, sdp->sd_log_flush_head);
        struct buffer_head *bh;

        bh = sb_getblk(sdp->sd_vfs, blkno);
        lock_buffer(bh);
        memset(bh->b_data, 0, bh->b_size);
        set_buffer_uptodate(bh);
        clear_buffer_dirty(bh);
        gfs2_log_incr_head(sdp);
        atomic_inc(&sdp->sd_log_in_flight);
        bh->b_private = sdp;
        bh->b_end_io = gfs2_log_write_endio;

        return bh;
}

/**
 * gfs2_fake_write_endio - 
 * @bh: The buffer head
 * @uptodate: The I/O Status
 *
 */

static void gfs2_fake_write_endio(struct buffer_head *bh, int uptodate)
{
        struct buffer_head *real_bh = bh->b_private;
        struct gfs2_bufdata *bd = real_bh->b_private;
        struct gfs2_sbd *sdp = bd->bd_gl->gl_sbd;

        end_buffer_write_sync(bh, uptodate);
        mempool_free(bh, gfs2_bh_pool);
        unlock_buffer(real_bh);
        brelse(real_bh);
        if (atomic_dec_and_test(&sdp->sd_log_in_flight))
                wake_up(&sdp->sd_log_flush_wait);
}

/**
 * gfs2_log_fake_buf - Build a fake buffer head to write metadata buffer to log
 * @sdp: the filesystem
 * @data: the data the buffer_head should point to
 *
 * Returns: the log buffer descriptor
 */

static struct buffer_head *gfs2_log_fake_buf(struct gfs2_sbd *sdp,
                                      struct buffer_head *real)
{
        u64 blkno = gfs2_log_bmap(sdp, sdp->sd_log_flush_head);
        struct buffer_head *bh;

        bh = mempool_alloc(gfs2_bh_pool, GFP_NOFS);
        atomic_set(&bh->b_count, 1);
        bh->b_state = (1 << BH_Mapped) | (1 << BH_Uptodate) | (1 << BH_Lock);
        set_bh_page(bh, real->b_page, bh_offset(real));
        bh->b_blocknr = blkno;
        bh->b_size = sdp->sd_sb.sb_bsize;
        bh->b_bdev = sdp->sd_vfs->s_bdev;
        bh->b_private = real;
        bh->b_end_io = gfs2_fake_write_endio;

        gfs2_log_incr_head(sdp);
        atomic_inc(&sdp->sd_log_in_flight);

        return bh;
}

static struct buffer_head *gfs2_get_log_desc(struct gfs2_sbd *sdp, u32 ld_type)
{
        struct buffer_head *bh = gfs2_log_get_buf(sdp);
        struct gfs2_log_descriptor *ld = bh_log_desc(bh);
        ld->ld_header.mh_magic = cpu_to_be32(GFS2_MAGIC);
        ld->ld_header.mh_type = cpu_to_be32(GFS2_METATYPE_LD);
        ld->ld_header.mh_format = cpu_to_be32(GFS2_FORMAT_LD);
        ld->ld_type = cpu_to_be32(ld_type);
        ld->ld_length = 0;
        ld->ld_data1 = 0;
        ld->ld_data2 = 0;
        memset(ld->ld_reserved, 0, sizeof(ld->ld_reserved));
        return bh;
}

static void buf_lo_add(struct gfs2_sbd *sdp, struct gfs2_log_element *le)
{
        struct gfs2_bufdata *bd = container_of(le, struct gfs2_bufdata, bd_le);
        struct gfs2_meta_header *mh;
        struct gfs2_trans *tr;

        lock_buffer(bd->bd_bh);
        gfs2_log_lock(sdp);
        if (!list_empty(&bd->bd_list_tr))
                goto out;
        tr = current->journal_info;
        tr->tr_touched = 1;
        tr->tr_num_buf++;
        list_add(&bd->bd_list_tr, &tr->tr_list_buf);
        if (!list_empty(&le->le_list))
                goto out;
        set_bit(GLF_LFLUSH, &bd->bd_gl->gl_flags);
        set_bit(GLF_DIRTY, &bd->bd_gl->gl_flags);
        gfs2_meta_check(sdp, bd->bd_bh);
        gfs2_pin(sdp, bd->bd_bh);
        mh = (struct gfs2_meta_header *)bd->bd_bh->b_data;
        mh->__pad0 = cpu_to_be64(0);
        mh->mh_jid = cpu_to_be32(sdp->sd_jdesc->jd_jid);
        sdp->sd_log_num_buf++;
        list_add(&le->le_list, &sdp->sd_log_le_buf);
        tr->tr_num_buf_new++;
out:
        gfs2_log_unlock(sdp);
        unlock_buffer(bd->bd_bh);
}

static void buf_lo_before_commit(struct gfs2_sbd *sdp)
{
        struct buffer_head *bh;
        struct gfs2_log_descriptor *ld;
        struct gfs2_bufdata *bd1 = NULL, *bd2;
        unsigned int total;
        unsigned int limit;
        unsigned int num;
        unsigned n;
        __be64 *ptr;

        limit = buf_limit(sdp);
        /* for 4k blocks, limit = 503 */

        gfs2_log_lock(sdp);
        total = sdp->sd_log_num_buf;
        bd1 = bd2 = list_prepare_entry(bd1, &sdp->sd_log_le_buf, bd_le.le_list);
        while(total) {
                num = total;
                if (total > limit)
                        num = limit;
                gfs2_log_unlock(sdp);
                bh = gfs2_get_log_desc(sdp, GFS2_LOG_DESC_METADATA);
                gfs2_log_lock(sdp);
                ld = bh_log_desc(bh);
                ptr = bh_log_ptr(bh);
                ld->ld_length = cpu_to_be32(num + 1);
                ld->ld_data1 = cpu_to_be32(num);

                n = 0;
                list_for_each_entry_continue(bd1, &sdp->sd_log_le_buf,
                                             bd_le.le_list) {
                        *ptr++ = cpu_to_be64(bd1->bd_bh->b_blocknr);
                        if (++n >= num)
                                break;
                }

                gfs2_log_unlock(sdp);
                submit_bh(WRITE_SYNC, bh);
                gfs2_log_lock(sdp);

                n = 0;
                list_for_each_entry_continue(bd2, &sdp->sd_log_le_buf,
                                             bd_le.le_list) {
                        get_bh(bd2->bd_bh);
                        gfs2_log_unlock(sdp);
                        lock_buffer(bd2->bd_bh);
                        bh = gfs2_log_fake_buf(sdp, bd2->bd_bh);
                        submit_bh(WRITE_SYNC, bh);
                        gfs2_log_lock(sdp);
                        if (++n >= num)
                                break;
                }

                BUG_ON(total < num);
                total -= num;
        }
        gfs2_log_unlock(sdp);
}

static void buf_lo_after_commit(struct gfs2_sbd *sdp, struct gfs2_ail *ai)
{
        struct list_head *head = &sdp->sd_log_le_buf;
        struct gfs2_bufdata *bd;

        while (!list_empty(head)) {
                bd = list_entry(head->next, struct gfs2_bufdata, bd_le.le_list);
                list_del_init(&bd->bd_le.le_list);
                sdp->sd_log_num_buf--;

                gfs2_unpin(sdp, bd->bd_bh, ai);
        }
        gfs2_assert_warn(sdp, !sdp->sd_log_num_buf);
}

static void buf_lo_before_scan(struct gfs2_jdesc *jd,
                               struct gfs2_log_header_host *head, int pass)
{
        struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);

        if (pass != 0)
                return;

        sdp->sd_found_blocks = 0;
        sdp->sd_replayed_blocks = 0;
}

static int buf_lo_scan_elements(struct gfs2_jdesc *jd, unsigned int start,
                                struct gfs2_log_descriptor *ld, __be64 *ptr,
                                int pass)
{
        struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
        struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
        struct gfs2_glock *gl = ip->i_gl;
        unsigned int blks = be32_to_cpu(ld->ld_data1);
        struct buffer_head *bh_log, *bh_ip;
        u64 blkno;
        int error = 0;

        if (pass != 1 || be32_to_cpu(ld->ld_type) != GFS2_LOG_DESC_METADATA)
                return 0;

        gfs2_replay_incr_blk(sdp, &start);

        for (; blks; gfs2_replay_incr_blk(sdp, &start), blks--) {
                blkno = be64_to_cpu(*ptr++);

                sdp->sd_found_blocks++;

                if (gfs2_revoke_check(sdp, blkno, start))
                        continue;

                error = gfs2_replay_read_block(jd, start, &bh_log);
                if (error)
                        return error;

                bh_ip = gfs2_meta_new(gl, blkno);
                memcpy(bh_ip->b_data, bh_log->b_data, bh_log->b_size);

                if (gfs2_meta_check(sdp, bh_ip))
                        error = -EIO;
                else
                        mark_buffer_dirty(bh_ip);

                brelse(bh_log);
                brelse(bh_ip);

                if (error)
                        break;

                sdp->sd_replayed_blocks++;
        }

        return error;
}

static void buf_lo_after_scan(struct gfs2_jdesc *jd, int error, int pass)
{
        struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
        struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);

        if (error) {
                gfs2_meta_sync(ip->i_gl);
                return;
        }
        if (pass != 1)
                return;

        gfs2_meta_sync(ip->i_gl);

        fs_info(sdp, "jid=%u: Replayed %u of %u blocks\n",
                jd->jd_jid, sdp->sd_replayed_blocks, sdp->sd_found_blocks);
}

static void revoke_lo_add(struct gfs2_sbd *sdp, struct gfs2_log_element *le)
{
        struct gfs2_bufdata *bd = container_of(le, struct gfs2_bufdata, bd_le);
        struct gfs2_glock *gl = bd->bd_gl;
        struct gfs2_trans *tr;

        tr = current->journal_info;
        tr->tr_touched = 1;
        tr->tr_num_revoke++;
        sdp->sd_log_num_revoke++;
        atomic_inc(&gl->gl_revokes);
        set_bit(GLF_LFLUSH, &gl->gl_flags);
        list_add(&le->le_list, &sdp->sd_log_le_revoke);
}

static void revoke_lo_before_commit(struct gfs2_sbd *sdp)
{
        struct gfs2_log_descriptor *ld;
        struct gfs2_meta_header *mh;
        struct buffer_head *bh;
        unsigned int offset;
        struct list_head *head = &sdp->sd_log_le_revoke;
        struct gfs2_bufdata *bd;

        if (!sdp->sd_log_num_revoke)
                return;

        bh = gfs2_get_log_desc(sdp, GFS2_LOG_DESC_REVOKE);
        ld = bh_log_desc(bh);
        ld->ld_length = cpu_to_be32(gfs2_struct2blk(sdp, sdp->sd_log_num_revoke,
                                                    sizeof(u64)));
        ld->ld_data1 = cpu_to_be32(sdp->sd_log_num_revoke);
        offset = sizeof(struct gfs2_log_descriptor);

        list_for_each_entry(bd, head, bd_le.le_list) {
                sdp->sd_log_num_revoke--;

                if (offset + sizeof(u64) > sdp->sd_sb.sb_bsize) {
                        submit_bh(WRITE_SYNC, bh);

                        bh = gfs2_log_get_buf(sdp);
                        mh = (struct gfs2_meta_header *)bh->b_data;
                        mh->mh_magic = cpu_to_be32(GFS2_MAGIC);
                        mh->mh_type = cpu_to_be32(GFS2_METATYPE_LB);
                        mh->mh_format = cpu_to_be32(GFS2_FORMAT_LB);
                        offset = sizeof(struct gfs2_meta_header);
                }

                *(__be64 *)(bh->b_data + offset) = cpu_to_be64(bd->bd_blkno);
                offset += sizeof(u64);
        }
        gfs2_assert_withdraw(sdp, !sdp->sd_log_num_revoke);

        submit_bh(WRITE_SYNC, bh);
}

static void revoke_lo_after_commit(struct gfs2_sbd *sdp, struct gfs2_ail *ai)
{
        struct list_head *head = &sdp->sd_log_le_revoke;
        struct gfs2_bufdata *bd;
        struct gfs2_glock *gl;

        while (!list_empty(head)) {
                bd = list_entry(head->next, struct gfs2_bufdata, bd_le.le_list);
                list_del_init(&bd->bd_le.le_list);
                gl = bd->bd_gl;
                atomic_dec(&gl->gl_revokes);
                clear_bit(GLF_LFLUSH, &gl->gl_flags);
                kmem_cache_free(gfs2_bufdata_cachep, bd);
        }
}

static void revoke_lo_before_scan(struct gfs2_jdesc *jd,
                                  struct gfs2_log_header_host *head, int pass)
{
        struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);

        if (pass != 0)
                return;

        sdp->sd_found_revokes = 0;
        sdp->sd_replay_tail = head->lh_tail;
}

static int revoke_lo_scan_elements(struct gfs2_jdesc *jd, unsigned int start,
                                   struct gfs2_log_descriptor *ld, __be64 *ptr,
                                   int pass)
{
        struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
        unsigned int blks = be32_to_cpu(ld->ld_length);
        unsigned int revokes = be32_to_cpu(ld->ld_data1);
        struct buffer_head *bh;
        unsigned int offset;
        u64 blkno;
        int first = 1;
        int error;

        if (pass != 0 || be32_to_cpu(ld->ld_type) != GFS2_LOG_DESC_REVOKE)
                return 0;

        offset = sizeof(struct gfs2_log_descriptor);

        for (; blks; gfs2_replay_incr_blk(sdp, &start), blks--) {
                error = gfs2_replay_read_block(jd, start, &bh);
                if (error)
                        return error;

                if (!first)
                        gfs2_metatype_check(sdp, bh, GFS2_METATYPE_LB);

                while (offset + sizeof(u64) <= sdp->sd_sb.sb_bsize) {
                        blkno = be64_to_cpu(*(__be64 *)(bh->b_data + offset));

                        error = gfs2_revoke_add(sdp, blkno, start);
                        if (error < 0) {
                                brelse(bh);
                                return error;
                        }
                        else if (error)
                                sdp->sd_found_revokes++;

                        if (!--revokes)
                                break;
                        offset += sizeof(u64);
                }

                brelse(bh);
                offset = sizeof(struct gfs2_meta_header);
                first = 0;
        }

        return 0;
}

static void revoke_lo_after_scan(struct gfs2_jdesc *jd, int error, int pass)
{
        struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);

        if (error) {
                gfs2_revoke_clean(sdp);
                return;
        }
        if (pass != 1)
                return;

        fs_info(sdp, "jid=%u: Found %u revoke tags\n",
                jd->jd_jid, sdp->sd_found_revokes);

        gfs2_revoke_clean(sdp);
}

/**
 * databuf_lo_add - Add a databuf to the transaction.
 *
 * 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.
 */
static void databuf_lo_add(struct gfs2_sbd *sdp, struct gfs2_log_element *le)
{
        struct gfs2_bufdata *bd = container_of(le, struct gfs2_bufdata, bd_le);
        struct gfs2_trans *tr = current->journal_info;
        struct address_space *mapping = bd->bd_bh->b_page->mapping;
        struct gfs2_inode *ip = GFS2_I(mapping->host);

        lock_buffer(bd->bd_bh);
        gfs2_log_lock(sdp);
        if (tr) {
                if (!list_empty(&bd->bd_list_tr))
                        goto out;
                tr->tr_touched = 1;
                if (gfs2_is_jdata(ip)) {
                        tr->tr_num_buf++;
                        list_add(&bd->bd_list_tr, &tr->tr_list_buf);
                }
        }
        if (!list_empty(&le->le_list))
                goto out;

        set_bit(GLF_LFLUSH, &bd->bd_gl->gl_flags);
        set_bit(GLF_DIRTY, &bd->bd_gl->gl_flags);
        if (gfs2_is_jdata(ip)) {
                gfs2_pin(sdp, bd->bd_bh);
                tr->tr_num_databuf_new++;
                sdp->sd_log_num_databuf++;
                list_add_tail(&le->le_list, &sdp->sd_log_le_databuf);
        } else {
                list_add_tail(&le->le_list, &sdp->sd_log_le_ordered);
        }
out:
        gfs2_log_unlock(sdp);
        unlock_buffer(bd->bd_bh);
}

static void gfs2_check_magic(struct buffer_head *bh)
{
        void *kaddr;
        __be32 *ptr;

        clear_buffer_escaped(bh);
        kaddr = kmap_atomic(bh->b_page);
        ptr = kaddr + bh_offset(bh);
        if (*ptr == cpu_to_be32(GFS2_MAGIC))
                set_buffer_escaped(bh);
        kunmap_atomic(kaddr);
}

static void gfs2_write_blocks(struct gfs2_sbd *sdp, struct buffer_head *bh,
                              struct list_head *list, struct list_head *done,
                              unsigned int n)
{
        struct buffer_head *bh1;
        struct gfs2_log_descriptor *ld;
        struct gfs2_bufdata *bd;
        __be64 *ptr;

        if (!bh)
                return;

        ld = bh_log_desc(bh);
        ld->ld_length = cpu_to_be32(n + 1);
        ld->ld_data1 = cpu_to_be32(n);

        ptr = bh_log_ptr(bh);
        
        get_bh(bh);
        submit_bh(WRITE_SYNC, bh);
        gfs2_log_lock(sdp);
        while(!list_empty(list)) {
                bd = list_entry(list->next, struct gfs2_bufdata, bd_le.le_list);
                list_move_tail(&bd->bd_le.le_list, done);
                get_bh(bd->bd_bh);
                while (be64_to_cpu(*ptr) != bd->bd_bh->b_blocknr) {
                        gfs2_log_incr_head(sdp);
                        ptr += 2;
                }
                gfs2_log_unlock(sdp);
                lock_buffer(bd->bd_bh);
                if (buffer_escaped(bd->bd_bh)) {
                        void *kaddr;
                        bh1 = gfs2_log_get_buf(sdp);
                        kaddr = kmap_atomic(bd->bd_bh->b_page);
                        memcpy(bh1->b_data, kaddr + bh_offset(bd->bd_bh),
                               bh1->b_size);
                        kunmap_atomic(kaddr);
                        *(__be32 *)bh1->b_data = 0;
                        clear_buffer_escaped(bd->bd_bh);
                        unlock_buffer(bd->bd_bh);
                        brelse(bd->bd_bh);
                } else {
                        bh1 = gfs2_log_fake_buf(sdp, bd->bd_bh);
                }
                submit_bh(WRITE_SYNC, bh1);
                gfs2_log_lock(sdp);
                ptr += 2;
        }
        gfs2_log_unlock(sdp);
        brelse(bh);
}

/**
 * databuf_lo_before_commit - Scan the data buffers, writing as we go
 *
 */

static void databuf_lo_before_commit(struct gfs2_sbd *sdp)
{
        struct gfs2_bufdata *bd = NULL;
        struct buffer_head *bh = NULL;
        unsigned int n = 0;
        __be64 *ptr = NULL, *end = NULL;
        LIST_HEAD(processed);
        LIST_HEAD(in_progress);

        gfs2_log_lock(sdp);
        while (!list_empty(&sdp->sd_log_le_databuf)) {
                if (ptr == end) {
                        gfs2_log_unlock(sdp);
                        gfs2_write_blocks(sdp, bh, &in_progress, &processed, n);
                        n = 0;
                        bh = gfs2_get_log_desc(sdp, GFS2_LOG_DESC_JDATA);
                        ptr = bh_log_ptr(bh);
                        end = bh_ptr_end(bh) - 1;
                        gfs2_log_lock(sdp);
                        continue;
                }
                bd = list_entry(sdp->sd_log_le_databuf.next, struct gfs2_bufdata, bd_le.le_list);
                list_move_tail(&bd->bd_le.le_list, &in_progress);
                gfs2_check_magic(bd->bd_bh);
                *ptr++ = cpu_to_be64(bd->bd_bh->b_blocknr);
                *ptr++ = cpu_to_be64(buffer_escaped(bh) ? 1 : 0);
                n++;
        }
        gfs2_log_unlock(sdp);
        gfs2_write_blocks(sdp, bh, &in_progress, &processed, n);
        gfs2_log_lock(sdp);
        list_splice(&processed, &sdp->sd_log_le_databuf);
        gfs2_log_unlock(sdp);
}

static int databuf_lo_scan_elements(struct gfs2_jdesc *jd, unsigned int start,
                                    struct gfs2_log_descriptor *ld,
                                    __be64 *ptr, int pass)
{
        struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
        struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
        struct gfs2_glock *gl = ip->i_gl;
        unsigned int blks = be32_to_cpu(ld->ld_data1);
        struct buffer_head *bh_log, *bh_ip;
        u64 blkno;
        u64 esc;
        int error = 0;

        if (pass != 1 || be32_to_cpu(ld->ld_type) != GFS2_LOG_DESC_JDATA)
                return 0;

        gfs2_replay_incr_blk(sdp, &start);
        for (; blks; gfs2_replay_incr_blk(sdp, &start), blks--) {
                blkno = be64_to_cpu(*ptr++);
                esc = be64_to_cpu(*ptr++);

                sdp->sd_found_blocks++;

                if (gfs2_revoke_check(sdp, blkno, start))
                        continue;

                error = gfs2_replay_read_block(jd, start, &bh_log);
                if (error)
                        return error;

                bh_ip = gfs2_meta_new(gl, blkno);
                memcpy(bh_ip->b_data, bh_log->b_data, bh_log->b_size);

                /* Unescape */
                if (esc) {
                        __be32 *eptr = (__be32 *)bh_ip->b_data;
                        *eptr = cpu_to_be32(GFS2_MAGIC);
                }
                mark_buffer_dirty(bh_ip);

                brelse(bh_log);
                brelse(bh_ip);

                sdp->sd_replayed_blocks++;
        }

        return error;
}

/* FIXME: sort out accounting for log blocks etc. */

static void databuf_lo_after_scan(struct gfs2_jdesc *jd, int error, int pass)
{
        struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
        struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);

        if (error) {
                gfs2_meta_sync(ip->i_gl);
                return;
        }
        if (pass != 1)
                return;

        /* data sync? */
        gfs2_meta_sync(ip->i_gl);

        fs_info(sdp, "jid=%u: Replayed %u of %u data blocks\n",
                jd->jd_jid, sdp->sd_replayed_blocks, sdp->sd_found_blocks);
}

static void databuf_lo_after_commit(struct gfs2_sbd *sdp, struct gfs2_ail *ai)
{
        struct list_head *head = &sdp->sd_log_le_databuf;
        struct gfs2_bufdata *bd;

        while (!list_empty(head)) {
                bd = list_entry(head->next, struct gfs2_bufdata, bd_le.le_list);
                list_del_init(&bd->bd_le.le_list);
                sdp->sd_log_num_databuf--;
                gfs2_unpin(sdp, bd->bd_bh, ai);
        }
        gfs2_assert_warn(sdp, !sdp->sd_log_num_databuf);
}


const struct gfs2_log_operations gfs2_buf_lops = {
        .lo_add = buf_lo_add,
        .lo_before_commit = buf_lo_before_commit,
        .lo_after_commit = buf_lo_after_commit,
        .lo_before_scan = buf_lo_before_scan,
        .lo_scan_elements = buf_lo_scan_elements,
        .lo_after_scan = buf_lo_after_scan,
        .lo_name = "buf",
};

const struct gfs2_log_operations gfs2_revoke_lops = {
        .lo_add = revoke_lo_add,
        .lo_before_commit = revoke_lo_before_commit,
        .lo_after_commit = revoke_lo_after_commit,
        .lo_before_scan = revoke_lo_before_scan,
        .lo_scan_elements = revoke_lo_scan_elements,
        .lo_after_scan = revoke_lo_after_scan,
        .lo_name = "revoke",
};

const struct gfs2_log_operations gfs2_rg_lops = {
        .lo_name = "rg",
};

const struct gfs2_log_operations gfs2_databuf_lops = {
        .lo_add = databuf_lo_add,
        .lo_before_commit = databuf_lo_before_commit,
        .lo_after_commit = databuf_lo_after_commit,
        .lo_scan_elements = databuf_lo_scan_elements,
        .lo_after_scan = databuf_lo_after_scan,
        .lo_name = "databuf",
};

const struct gfs2_log_operations *gfs2_log_ops[] = {
        &gfs2_databuf_lops,
        &gfs2_buf_lops,
        &gfs2_rg_lops,
        &gfs2_revoke_lops,
        NULL,
};