text: /*
   * 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.
   */
  
  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  
  #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 = _RET_IP_;
  	tr->tr_blocks = blocks;
  	tr->tr_revokes = revokes;
  	tr->tr_reserved = 1;
  	set_bit(TR_ALLOCED, &tr->tr_flags);
  	if (blocks)
  		tr->tr_reserved += 6 + blocks;
  	if (revokes)
  		tr->tr_reserved += gfs2_struct2blk(sdp, revokes,
  						   sizeof(u64));
  	INIT_LIST_HEAD(&tr->tr_databuf);
  	INIT_LIST_HEAD(&tr->tr_buf);
  
  	sb_start_intwrite(sdp->sd_vfs);
  
  	error = gfs2_log_reserve(sdp, tr->tr_reserved);
  	if (error)
  		goto fail;
  
  	current->journal_info = tr;
  
  	return 0;
  
  fail:
  	sb_end_intwrite(sdp->sd_vfs);
  	kfree(tr);
  
  	return error;
  }
  
  static void gfs2_print_trans(struct gfs2_sbd *sdp, const struct gfs2_trans *tr)
  {
  	fs_warn(sdp, "Transaction created at: %pSR\n", (void *)tr->tr_ip);
  	fs_warn(sdp, "blocks=%u revokes=%u reserved=%u touched=%u\n",
  		tr->tr_blocks, tr->tr_revokes, tr->tr_reserved,
  		test_bit(TR_TOUCHED, &tr->tr_flags));
  	fs_warn(sdp, "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;
  	int alloced = test_bit(TR_ALLOCED, &tr->tr_flags);
  
  	current->journal_info = NULL;
  
  	if (!test_bit(TR_TOUCHED, &tr->tr_flags)) {
  		gfs2_log_release(sdp, tr->tr_reserved);
  		if (alloced) {
  			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(sdp, tr);
  
  	gfs2_log_commit(sdp, tr);
  	if (alloced && !test_bit(TR_ATTACHED, &tr->tr_flags))
  		kfree(tr);
  	up_read(&sdp->sd_log_flush_lock);
  
  	if (sdp->sd_vfs->s_flags & SB_SYNCHRONOUS)
  		gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_NORMAL |
  			       GFS2_LFC_TRANS_END);
  	if (alloced)
  		sb_end_intwrite(sdp->sd_vfs);
  }
  
  static struct gfs2_bufdata *gfs2_alloc_bufdata(struct gfs2_glock *gl,
  					       struct buffer_head *bh)
  {
  	struct gfs2_bufdata *bd;
  
  	bd = kmem_cache_zalloc(gfs2_bufdata_cachep, GFP_NOFS | __GFP_NOFAIL);
  	bd->bd_bh = bh;
  	bd->bd_gl = gl;
  	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 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_name.ln_sbd;
  	struct gfs2_bufdata *bd;
  
  	lock_buffer(bh);
  	if (buffer_pinned(bh)) {
  		set_bit(TR_TOUCHED, &tr->tr_flags);
  		goto out;
  	}
  	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);
  		else
  			bd = bh->b_private;
  		lock_buffer(bh);
  		gfs2_log_lock(sdp);
  	}
  	gfs2_assert(sdp, bd->bd_gl == gl);
  	set_bit(TR_TOUCHED, &tr->tr_flags);
  	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++;
  		list_add_tail(&bd->bd_list, &tr->tr_databuf);
  	}
  	gfs2_log_unlock(sdp);
  out:
  	unlock_buffer(bh);
  }
  
  void gfs2_trans_add_meta(struct gfs2_glock *gl, struct buffer_head *bh)
  {
  
  	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
  	struct gfs2_bufdata *bd;
  	struct gfs2_meta_header *mh;
  	struct gfs2_trans *tr = current->journal_info;
  	enum gfs2_freeze_state state = atomic_read(&sdp->sd_freeze_state);
  
  	lock_buffer(bh);
  	if (buffer_pinned(bh)) {
  		set_bit(TR_TOUCHED, &tr->tr_flags);
  		goto out;
  	}
  	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);
  		else
  			bd = bh->b_private;
  		unlock_page(bh->b_page);
  		lock_buffer(bh);
  		gfs2_log_lock(sdp);
  	}
  	gfs2_assert(sdp, bd->bd_gl == gl);
  	set_bit(TR_TOUCHED, &tr->tr_flags);
  	if (!list_empty(&bd->bd_list))
  		goto out_unlock;
  	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))) {
  		fs_err(sdp, "Attempting to add uninitialised block to "
  		       "journal (inplace block=%lld)\n",
  		       (unsigned long long)bd->bd_bh->b_blocknr);
  		BUG();
  	}
  	if (unlikely(state == SFS_FROZEN)) {
  		fs_info(sdp, "GFS2:adding buf while frozen\n");
  		gfs2_assert_withdraw(sdp, 0);
  	}
  	gfs2_pin(sdp, bd->bd_bh);
  	mh->__pad0 = cpu_to_be64(0);
  	mh->mh_jid = cpu_to_be32(sdp->sd_jdesc->jd_jid);
  	list_add(&bd->bd_list, &tr->tr_buf);
  	tr->tr_num_buf_new++;
  out_unlock:
  	gfs2_log_unlock(sdp);
  out:
  	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);
  	set_bit(TR_TOUCHED, &tr->tr_flags);
  	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);
  }
  
  