/*
   * 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/slab.h>
  #include <linux/spinlock.h>
  #include <linux/completion.h>
  #include <linux/buffer_head.h>

  #include <linux/gfs2_ondisk.h>

  #include <linux/lm_interface.h>

  
  #include "gfs2.h"

  #include "incore.h"

  #include "bmap.h"
  #include "glock.h"
  #include "glops.h"
  #include "inode.h"
  #include "log.h"
  #include "meta_io.h"

  #include "recovery.h"
  #include "rgrp.h"

  #include "util.h"

  #include "trans.h"

  /**
   * ail_empty_gl - remove all buffers for a given lock from the AIL
   * @gl: the glock
   *
   * None of the buffers should be dirty, locked, or pinned.
   */
  
  static void gfs2_ail_empty_gl(struct gfs2_glock *gl)
  {
  	struct gfs2_sbd *sdp = gl->gl_sbd;
  	unsigned int blocks;
  	struct list_head *head = &gl->gl_ail_list;
  	struct gfs2_bufdata *bd;
  	struct buffer_head *bh;
  	u64 blkno;
  	int error;
  
  	blocks = atomic_read(&gl->gl_ail_count);
  	if (!blocks)
  		return;
  
  	error = gfs2_trans_begin(sdp, 0, blocks);
  	if (gfs2_assert_withdraw(sdp, !error))
  		return;
  
  	gfs2_log_lock(sdp);
  	while (!list_empty(head)) {
  		bd = list_entry(head->next, struct gfs2_bufdata,
  				bd_ail_gl_list);
  		bh = bd->bd_bh;
  		blkno = bh->b_blocknr;
  		gfs2_assert_withdraw(sdp, !buffer_busy(bh));
  
  		bd->bd_ail = NULL;
  		list_del(&bd->bd_ail_st_list);
  		list_del(&bd->bd_ail_gl_list);
  		atomic_dec(&gl->gl_ail_count);
  		brelse(bh);
  		gfs2_log_unlock(sdp);
  
  		gfs2_trans_add_revoke(sdp, blkno);
  
  		gfs2_log_lock(sdp);
  	}
  	gfs2_assert_withdraw(sdp, !atomic_read(&gl->gl_ail_count));
  	gfs2_log_unlock(sdp);
  
  	gfs2_trans_end(sdp);
  	gfs2_log_flush(sdp, NULL);
  }

  
  /**
   * gfs2_pte_inval - Sync and invalidate all PTEs associated with a glock
   * @gl: the glock
   *
   */
  
  static void gfs2_pte_inval(struct gfs2_glock *gl)
  {
  	struct gfs2_inode *ip;
  	struct inode *inode;
  
  	ip = gl->gl_object;
  	inode = &ip->i_inode;

  	if (!ip || !S_ISREG(inode->i_mode))

  		return;
  
  	if (!test_bit(GIF_PAGED, &ip->i_flags))
  		return;
  
  	unmap_shared_mapping_range(inode->i_mapping, 0, 0);
  
  	if (test_bit(GIF_SW_PAGED, &ip->i_flags))
  		set_bit(GLF_DIRTY, &gl->gl_flags);
  
  	clear_bit(GIF_SW_PAGED, &ip->i_flags);
  }
  
  /**

   * meta_go_sync - sync out the metadata for this glock
   * @gl: the glock

   *
   * Called when demoting or unlocking an EX glock.  We must flush
   * to disk all dirty buffers/pages relating to this glock, and must not
   * not return to caller to demote/unlock the glock until I/O is complete.
   */

  static void meta_go_sync(struct gfs2_glock *gl)

  {

  	if (gl->gl_state != LM_ST_EXCLUSIVE)
  		return;

  	if (test_and_clear_bit(GLF_DIRTY, &gl->gl_flags)) {

  		gfs2_log_flush(gl->gl_sbd, gl);

  		gfs2_meta_sync(gl);

  		gfs2_ail_empty_gl(gl);

  	}

  }
  
  /**
   * meta_go_inval - invalidate the metadata for this glock
   * @gl: the glock
   * @flags:
   *
   */
  
  static void meta_go_inval(struct gfs2_glock *gl, int flags)
  {
  	if (!(flags & DIO_METADATA))
  		return;
  
  	gfs2_meta_inval(gl);
  	gl->gl_vn++;
  }
  
  /**

   * inode_go_sync - Sync the dirty data and/or metadata for an inode glock
   * @gl: the glock protecting the inode
   *
   */
  
  static void inode_go_sync(struct gfs2_glock *gl)
  {
  	struct gfs2_inode *ip = gl->gl_object;
  
  	if (ip && !S_ISREG(ip->i_inode.i_mode))
  		ip = NULL;
  
  	if (test_bit(GLF_DIRTY, &gl->gl_flags)) {

  		if (ip)
  			filemap_fdatawrite(ip->i_inode.i_mapping);

  		gfs2_log_flush(gl->gl_sbd, gl);

  		gfs2_meta_sync(gl);
  		if (ip) {
  			struct address_space *mapping = ip->i_inode.i_mapping;
  			int error = filemap_fdatawait(mapping);

  			mapping_set_error(mapping, error);

  		}
  		clear_bit(GLF_DIRTY, &gl->gl_flags);
  		gfs2_ail_empty_gl(gl);
  	}
  }
  
  /**

   * inode_go_xmote_th - promote/demote a glock
   * @gl: the glock
   * @state: the requested state
   * @flags:
   *
   */

  static void inode_go_xmote_th(struct gfs2_glock *gl)

  {
  	if (gl->gl_state != LM_ST_UNLOCKED)
  		gfs2_pte_inval(gl);

  	if (gl->gl_state == LM_ST_EXCLUSIVE)
  		inode_go_sync(gl);

  }
  
  /**
   * inode_go_xmote_bh - After promoting/demoting a glock
   * @gl: the glock
   *
   */
  
  static void inode_go_xmote_bh(struct gfs2_glock *gl)
  {
  	struct gfs2_holder *gh = gl->gl_req_gh;
  	struct buffer_head *bh;
  	int error;
  
  	if (gl->gl_state != LM_ST_UNLOCKED &&
  	    (!gh || !(gh->gh_flags & GL_SKIP))) {

  		error = gfs2_meta_read(gl, gl->gl_name.ln_number, 0, &bh);

  		if (!error)
  			brelse(bh);
  	}
  }
  
  /**
   * inode_go_drop_th - unlock a glock
   * @gl: the glock
   *
   * Invoked from rq_demote().
   * Another node needs the lock in EXCLUSIVE mode, or lock (unused for too long)
   * is being purged from our node's glock cache; we're dropping lock.
   */
  
  static void inode_go_drop_th(struct gfs2_glock *gl)
  {
  	gfs2_pte_inval(gl);

  	if (gl->gl_state == LM_ST_EXCLUSIVE)
  		inode_go_sync(gl);

  }
  
  /**
   * inode_go_inval - prepare a inode glock to be released
   * @gl: the glock
   * @flags:
   *
   */
  
  static void inode_go_inval(struct gfs2_glock *gl, int flags)
  {

  	struct gfs2_inode *ip = gl->gl_object;

  	int meta = (flags & DIO_METADATA);

  
  	if (meta) {
  		gfs2_meta_inval(gl);

  		if (ip)
  			set_bit(GIF_INVALID, &ip->i_flags);
  	}
  
  	if (ip && S_ISREG(ip->i_inode.i_mode)) {
  		truncate_inode_pages(ip->i_inode.i_mapping, 0);

  		clear_bit(GIF_PAGED, &ip->i_flags);

  	}

  }
  
  /**
   * inode_go_demote_ok - Check to see if it's ok to unlock an inode glock
   * @gl: the glock
   *
   * Returns: 1 if it's ok
   */
  
  static int inode_go_demote_ok(struct gfs2_glock *gl)
  {
  	struct gfs2_sbd *sdp = gl->gl_sbd;
  	int demote = 0;

  	if (!gl->gl_object && !gl->gl_aspace->i_mapping->nrpages)

  		demote = 1;
  	else if (!sdp->sd_args.ar_localcaching &&
  		 time_after_eq(jiffies, gl->gl_stamp +
  			       gfs2_tune_get(sdp, gt_demote_secs) * HZ))
  		demote = 1;
  
  	return demote;
  }
  
  /**
   * inode_go_lock - operation done after an inode lock is locked by a process
   * @gl: the glock
   * @flags:
   *
   * Returns: errno
   */
  
  static int inode_go_lock(struct gfs2_holder *gh)
  {
  	struct gfs2_glock *gl = gh->gh_gl;

  	struct gfs2_inode *ip = gl->gl_object;

  	int error = 0;
  
  	if (!ip)
  		return 0;

  	if (test_bit(GIF_INVALID, &ip->i_flags)) {

  		error = gfs2_inode_refresh(ip);
  		if (error)
  			return error;

  	}
  
  	if ((ip->i_di.di_flags & GFS2_DIF_TRUNC_IN_PROG) &&
  	    (gl->gl_state == LM_ST_EXCLUSIVE) &&

  	    (gh->gh_state == LM_ST_EXCLUSIVE))

  		error = gfs2_truncatei_resume(ip);
  
  	return error;
  }
  
  /**
   * inode_go_unlock - operation done before an inode lock is unlocked by a
   *		     process
   * @gl: the glock
   * @flags:
   *
   */
  
  static void inode_go_unlock(struct gfs2_holder *gh)
  {
  	struct gfs2_glock *gl = gh->gh_gl;

  	struct gfs2_inode *ip = gl->gl_object;

  	if (ip)
  		gfs2_meta_cache_flush(ip);

  }
  
  /**

   * rgrp_go_demote_ok - Check to see if it's ok to unlock a RG's glock
   * @gl: the glock
   *
   * Returns: 1 if it's ok
   */
  
  static int rgrp_go_demote_ok(struct gfs2_glock *gl)
  {
  	return !gl->gl_aspace->i_mapping->nrpages;
  }
  
  /**
   * rgrp_go_lock - operation done after an rgrp lock is locked by
   *    a first holder on this node.
   * @gl: the glock
   * @flags:
   *
   * Returns: errno
   */
  
  static int rgrp_go_lock(struct gfs2_holder *gh)
  {

  	return gfs2_rgrp_bh_get(gh->gh_gl->gl_object);

  }
  
  /**
   * rgrp_go_unlock - operation done before an rgrp lock is unlocked by
   *    a last holder on this node.
   * @gl: the glock
   * @flags:
   *
   */
  
  static void rgrp_go_unlock(struct gfs2_holder *gh)
  {

  	gfs2_rgrp_bh_put(gh->gh_gl->gl_object);

  }
  
  /**
   * trans_go_xmote_th - promote/demote the transaction glock
   * @gl: the glock
   * @state: the requested state
   * @flags:
   *
   */

  static void trans_go_xmote_th(struct gfs2_glock *gl)

  {
  	struct gfs2_sbd *sdp = gl->gl_sbd;
  
  	if (gl->gl_state != LM_ST_UNLOCKED &&
  	    test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags)) {
  		gfs2_meta_syncfs(sdp);
  		gfs2_log_shutdown(sdp);
  	}

  }
  
  /**
   * trans_go_xmote_bh - After promoting/demoting the transaction glock
   * @gl: the glock
   *
   */
  
  static void trans_go_xmote_bh(struct gfs2_glock *gl)
  {
  	struct gfs2_sbd *sdp = gl->gl_sbd;

  	struct gfs2_inode *ip = GFS2_I(sdp->sd_jdesc->jd_inode);

  	struct gfs2_glock *j_gl = ip->i_gl;

  	struct gfs2_log_header_host head;

  	int error;
  
  	if (gl->gl_state != LM_ST_UNLOCKED &&
  	    test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags)) {

  		gfs2_meta_cache_flush(GFS2_I(sdp->sd_jdesc->jd_inode));

  		j_gl->gl_ops->go_inval(j_gl, DIO_METADATA);

  
  		error = gfs2_find_jhead(sdp->sd_jdesc, &head);
  		if (error)
  			gfs2_consist(sdp);
  		if (!(head.lh_flags & GFS2_LOG_HEAD_UNMOUNT))
  			gfs2_consist(sdp);
  
  		/*  Initialize some head of the log stuff  */
  		if (!test_bit(SDF_SHUTDOWN, &sdp->sd_flags)) {
  			sdp->sd_log_sequence = head.lh_sequence + 1;
  			gfs2_log_pointers_init(sdp, head.lh_blkno);
  		}
  	}
  }
  
  /**
   * trans_go_drop_th - unlock the transaction glock
   * @gl: the glock
   *
   * We want to sync the device even with localcaching.  Remember
   * that localcaching journal replay only marks buffers dirty.
   */
  
  static void trans_go_drop_th(struct gfs2_glock *gl)
  {
  	struct gfs2_sbd *sdp = gl->gl_sbd;
  
  	if (test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags)) {
  		gfs2_meta_syncfs(sdp);
  		gfs2_log_shutdown(sdp);
  	}

  }
  
  /**
   * quota_go_demote_ok - Check to see if it's ok to unlock a quota glock
   * @gl: the glock
   *
   * Returns: 1 if it's ok
   */
  
  static int quota_go_demote_ok(struct gfs2_glock *gl)
  {
  	return !atomic_read(&gl->gl_lvb_count);
  }

  const struct gfs2_glock_operations gfs2_meta_glops = {

  	.go_xmote_th = meta_go_sync,
  	.go_drop_th = meta_go_sync,

  	.go_type = LM_TYPE_META,

  };

  const struct gfs2_glock_operations gfs2_inode_glops = {

  	.go_xmote_th = inode_go_xmote_th,
  	.go_xmote_bh = inode_go_xmote_bh,
  	.go_drop_th = inode_go_drop_th,

  	.go_inval = inode_go_inval,
  	.go_demote_ok = inode_go_demote_ok,
  	.go_lock = inode_go_lock,
  	.go_unlock = inode_go_unlock,

  	.go_type = LM_TYPE_INODE,

  };

  const struct gfs2_glock_operations gfs2_rgrp_glops = {

  	.go_xmote_th = meta_go_sync,
  	.go_drop_th = meta_go_sync,

  	.go_inval = meta_go_inval,
  	.go_demote_ok = rgrp_go_demote_ok,
  	.go_lock = rgrp_go_lock,
  	.go_unlock = rgrp_go_unlock,

  	.go_type = LM_TYPE_RGRP,

  };

  const struct gfs2_glock_operations gfs2_trans_glops = {

  	.go_xmote_th = trans_go_xmote_th,
  	.go_xmote_bh = trans_go_xmote_bh,
  	.go_drop_th = trans_go_drop_th,

  	.go_type = LM_TYPE_NONDISK,

  };

  const struct gfs2_glock_operations gfs2_iopen_glops = {

  	.go_type = LM_TYPE_IOPEN,

  };

  const struct gfs2_glock_operations gfs2_flock_glops = {

  	.go_type = LM_TYPE_FLOCK,

  };

  const struct gfs2_glock_operations gfs2_nondisk_glops = {

  	.go_type = LM_TYPE_NONDISK,

  };

  const struct gfs2_glock_operations gfs2_quota_glops = {

  	.go_demote_ok = quota_go_demote_ok,

  	.go_type = LM_TYPE_QUOTA,

  };

  const struct gfs2_glock_operations gfs2_journal_glops = {

  	.go_type = LM_TYPE_JOURNAL,

  };