/*

   * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
   * 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.
   *

   * This program is distributed in the hope that it would 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 the Free Software Foundation,
   * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

   */

  #include "xfs.h"

  #include "xfs_fs.h"

  #include "xfs_types.h"

  #include "xfs_bit.h"

  #include "xfs_log.h"

  #include "xfs_inum.h"

  #include "xfs_trans.h"

  #include "xfs_sb.h"
  #include "xfs_ag.h"

  #include "xfs_mount.h"

  #include "xfs_bmap_btree.h"
  #include "xfs_alloc_btree.h"
  #include "xfs_ialloc_btree.h"

  #include "xfs_dinode.h"
  #include "xfs_inode.h"
  #include "xfs_buf_item.h"

  #include "xfs_trans_priv.h"
  #include "xfs_error.h"
  #include "xfs_rw.h"

  #include "xfs_trace.h"

  /*
   * Check to see if a buffer matching the given parameters is already
   * a part of the given transaction.
   */
  STATIC struct xfs_buf *
  xfs_trans_buf_item_match(
  	struct xfs_trans	*tp,
  	struct xfs_buftarg	*target,
  	xfs_daddr_t		blkno,
  	int			len)
  {

  	struct xfs_log_item_desc *lidp;
  	struct xfs_buf_log_item	*blip;

  	len = BBTOB(len);

  	list_for_each_entry(lidp, &tp->t_items, lid_trans) {
  		blip = (struct xfs_buf_log_item *)lidp->lid_item;
  		if (blip->bli_item.li_type == XFS_LI_BUF &&

  		    blip->bli_buf->b_target == target &&

  		    XFS_BUF_ADDR(blip->bli_buf) == blkno &&
  		    XFS_BUF_COUNT(blip->bli_buf) == len)
  			return blip->bli_buf;

  	}
  
  	return NULL;
  }

  /*
   * Add the locked buffer to the transaction.
   *
   * The buffer must be locked, and it cannot be associated with any
   * transaction.
   *
   * If the buffer does not yet have a buf log item associated with it,
   * then allocate one for it.  Then add the buf item to the transaction.
   */
  STATIC void
  _xfs_trans_bjoin(
  	struct xfs_trans	*tp,
  	struct xfs_buf		*bp,
  	int			reset_recur)
  {
  	struct xfs_buf_log_item	*bip;

  	ASSERT(bp->b_transp == NULL);

  
  	/*
  	 * The xfs_buf_log_item pointer is stored in b_fsprivate.  If
  	 * it doesn't have one yet, then allocate one and initialize it.
  	 * The checks to see if one is there are in xfs_buf_item_init().
  	 */
  	xfs_buf_item_init(bp, tp->t_mountp);

  	bip = bp->b_fspriv;

  	ASSERT(!(bip->bli_flags & XFS_BLI_STALE));

  	ASSERT(!(bip->bli_format.blf_flags & XFS_BLF_CANCEL));

  	ASSERT(!(bip->bli_flags & XFS_BLI_LOGGED));
  	if (reset_recur)
  		bip->bli_recur = 0;
  
  	/*
  	 * Take a reference for this transaction on the buf item.
  	 */
  	atomic_inc(&bip->bli_refcount);
  
  	/*
  	 * Get a log_item_desc to point at the new item.
  	 */

  	xfs_trans_add_item(tp, &bip->bli_item);

  
  	/*
  	 * Initialize b_fsprivate2 so we can find it with incore_match()
  	 * in xfs_trans_get_buf() and friends above.
  	 */

  	bp->b_transp = tp;

  
  }
  
  void
  xfs_trans_bjoin(
  	struct xfs_trans	*tp,
  	struct xfs_buf		*bp)
  {
  	_xfs_trans_bjoin(tp, bp, 0);
  	trace_xfs_trans_bjoin(bp->b_fspriv);
  }

  
  /*
   * Get and lock the buffer for the caller if it is not already
   * locked within the given transaction.  If it is already locked
   * within the transaction, just increment its lock recursion count
   * and return a pointer to it.
   *

   * If the transaction pointer is NULL, make this just a normal
   * get_buf() call.
   */
  xfs_buf_t *
  xfs_trans_get_buf(xfs_trans_t	*tp,
  		  xfs_buftarg_t	*target_dev,
  		  xfs_daddr_t	blkno,
  		  int		len,
  		  uint		flags)
  {
  	xfs_buf_t		*bp;
  	xfs_buf_log_item_t	*bip;
  
  	if (flags == 0)

  		flags = XBF_LOCK | XBF_MAPPED;

  
  	/*
  	 * Default to a normal get_buf() call if the tp is NULL.
  	 */

  	if (tp == NULL)

  		return xfs_buf_get(target_dev, blkno, len,
  				   flags | XBF_DONT_BLOCK);

  
  	/*
  	 * If we find the buffer in the cache with this transaction
  	 * pointer in its b_fsprivate2 field, then we know we already
  	 * have it locked.  In this case we just increment the lock
  	 * recursion count and return the buffer to the caller.
  	 */

  	bp = xfs_trans_buf_item_match(tp, target_dev, blkno, len);

  	if (bp != NULL) {

  		ASSERT(xfs_buf_islocked(bp));

  		if (XFS_FORCED_SHUTDOWN(tp->t_mountp)) {
  			xfs_buf_stale(bp);

  			XFS_BUF_DONE(bp);
  		}

  		/*
  		 * If the buffer is stale then it was binval'ed
  		 * since last read.  This doesn't matter since the
  		 * caller isn't allowed to use the data anyway.
  		 */

  		else if (XFS_BUF_ISSTALE(bp))

  			ASSERT(!XFS_BUF_ISDELAYWRITE(bp));

  		ASSERT(bp->b_transp == tp);

  		bip = bp->b_fspriv;

  		ASSERT(bip != NULL);
  		ASSERT(atomic_read(&bip->bli_refcount) > 0);
  		bip->bli_recur++;

  		trace_xfs_trans_get_buf_recur(bip);

  		return (bp);
  	}
  
  	/*

  	 * We always specify the XBF_DONT_BLOCK flag within a transaction
  	 * so that get_buf does not try to push out a delayed write buffer

  	 * which might cause another transaction to take place (if the
  	 * buffer was delayed alloc).  Such recursive transactions can
  	 * easily deadlock with our current transaction as well as cause
  	 * us to run out of stack space.
  	 */

  	bp = xfs_buf_get(target_dev, blkno, len, flags | XBF_DONT_BLOCK);

  	if (bp == NULL) {
  		return NULL;
  	}

  	ASSERT(!bp->b_error);

  	_xfs_trans_bjoin(tp, bp, 1);
  	trace_xfs_trans_get_buf(bp->b_fspriv);

  	return (bp);
  }
  
  /*
   * Get and lock the superblock buffer of this file system for the
   * given transaction.
   *
   * We don't need to use incore_match() here, because the superblock
   * buffer is a private buffer which we keep a pointer to in the
   * mount structure.
   */
  xfs_buf_t *
  xfs_trans_getsb(xfs_trans_t	*tp,
  		struct xfs_mount *mp,
  		int		flags)
  {
  	xfs_buf_t		*bp;
  	xfs_buf_log_item_t	*bip;
  
  	/*
  	 * Default to just trying to lock the superblock buffer
  	 * if tp is NULL.
  	 */
  	if (tp == NULL) {
  		return (xfs_getsb(mp, flags));
  	}
  
  	/*
  	 * If the superblock buffer already has this transaction
  	 * pointer in its b_fsprivate2 field, then we know we already
  	 * have it locked.  In this case we just increment the lock
  	 * recursion count and return the buffer to the caller.
  	 */
  	bp = mp->m_sb_bp;

  	if (bp->b_transp == tp) {

  		bip = bp->b_fspriv;

  		ASSERT(bip != NULL);
  		ASSERT(atomic_read(&bip->bli_refcount) > 0);
  		bip->bli_recur++;

  		trace_xfs_trans_getsb_recur(bip);

  		return (bp);
  	}
  
  	bp = xfs_getsb(mp, flags);

  	if (bp == NULL)

  		return NULL;

  	_xfs_trans_bjoin(tp, bp, 1);
  	trace_xfs_trans_getsb(bp->b_fspriv);

  	return (bp);
  }
  
  #ifdef DEBUG
  xfs_buftarg_t *xfs_error_target;
  int	xfs_do_error;
  int	xfs_req_num;
  int	xfs_error_mod = 33;
  #endif
  
  /*
   * Get and lock the buffer for the caller if it is not already
   * locked within the given transaction.  If it has not yet been
   * read in, read it from disk. If it is already locked
   * within the transaction and already read in, just increment its
   * lock recursion count and return a pointer to it.
   *

   * If the transaction pointer is NULL, make this just a normal
   * read_buf() call.
   */
  int
  xfs_trans_read_buf(
  	xfs_mount_t	*mp,
  	xfs_trans_t	*tp,
  	xfs_buftarg_t	*target,
  	xfs_daddr_t	blkno,
  	int		len,
  	uint		flags,
  	xfs_buf_t	**bpp)
  {
  	xfs_buf_t		*bp;
  	xfs_buf_log_item_t	*bip;
  	int			error;
  
  	if (flags == 0)

  		flags = XBF_LOCK | XBF_MAPPED;

  
  	/*
  	 * Default to a normal get_buf() call if the tp is NULL.
  	 */
  	if (tp == NULL) {

  		bp = xfs_buf_read(target, blkno, len, flags | XBF_DONT_BLOCK);

  		if (!bp)

  			return (flags & XBF_TRYLOCK) ?

  					EAGAIN : XFS_ERROR(ENOMEM);

  		if (bp->b_error) {
  			error = bp->b_error;

  			xfs_buf_ioerror_alert(bp, __func__);

  			xfs_buf_relse(bp);
  			return error;
  		}
  #ifdef DEBUG

  		if (xfs_do_error) {

  			if (xfs_error_target == target) {
  				if (((xfs_req_num++) % xfs_error_mod) == 0) {
  					xfs_buf_relse(bp);

  					xfs_debug(mp, "Returning error!");

  					return XFS_ERROR(EIO);
  				}
  			}
  		}
  #endif
  		if (XFS_FORCED_SHUTDOWN(mp))
  			goto shutdown_abort;
  		*bpp = bp;
  		return 0;
  	}
  
  	/*
  	 * If we find the buffer in the cache with this transaction
  	 * pointer in its b_fsprivate2 field, then we know we already
  	 * have it locked.  If it is already read in we just increment
  	 * the lock recursion count and return the buffer to the caller.
  	 * If the buffer is not yet read in, then we read it in, increment
  	 * the lock recursion count, and return it to the caller.
  	 */

  	bp = xfs_trans_buf_item_match(tp, target, blkno, len);

  	if (bp != NULL) {

  		ASSERT(xfs_buf_islocked(bp));

  		ASSERT(bp->b_transp == tp);

  		ASSERT(bp->b_fspriv != NULL);

  		ASSERT(!bp->b_error);

  		if (!(XFS_BUF_ISDONE(bp))) {

  			trace_xfs_trans_read_buf_io(bp, _RET_IP_);

  			ASSERT(!XFS_BUF_ISASYNC(bp));
  			XFS_BUF_READ(bp);
  			xfsbdstrat(tp->t_mountp, bp);

  			error = xfs_buf_iowait(bp);

  			if (error) {

  				xfs_buf_ioerror_alert(bp, __func__);

  				xfs_buf_relse(bp);
  				/*

  				 * We can gracefully recover from most read
  				 * errors. Ones we can't are those that happen
  				 * after the transaction's already dirty.

  				 */
  				if (tp->t_flags & XFS_TRANS_DIRTY)
  					xfs_force_shutdown(tp->t_mountp,

  							SHUTDOWN_META_IO_ERROR);

  				return error;
  			}
  		}
  		/*
  		 * We never locked this buf ourselves, so we shouldn't
  		 * brelse it either. Just get out.
  		 */
  		if (XFS_FORCED_SHUTDOWN(mp)) {

  			trace_xfs_trans_read_buf_shut(bp, _RET_IP_);

  			*bpp = NULL;
  			return XFS_ERROR(EIO);
  		}

  		bip = bp->b_fspriv;

  		bip->bli_recur++;
  
  		ASSERT(atomic_read(&bip->bli_refcount) > 0);

  		trace_xfs_trans_read_buf_recur(bip);

  		*bpp = bp;
  		return 0;
  	}
  
  	/*

  	 * We always specify the XBF_DONT_BLOCK flag within a transaction
  	 * so that get_buf does not try to push out a delayed write buffer

  	 * which might cause another transaction to take place (if the
  	 * buffer was delayed alloc).  Such recursive transactions can
  	 * easily deadlock with our current transaction as well as cause
  	 * us to run out of stack space.
  	 */

  	bp = xfs_buf_read(target, blkno, len, flags | XBF_DONT_BLOCK);

  	if (bp == NULL) {
  		*bpp = NULL;

  		return (flags & XBF_TRYLOCK) ?
  					0 : XFS_ERROR(ENOMEM);

  	}

  	if (bp->b_error) {
  		error = bp->b_error;

  		xfs_buf_stale(bp);

  		XFS_BUF_DONE(bp);

  		xfs_buf_ioerror_alert(bp, __func__);

  		if (tp->t_flags & XFS_TRANS_DIRTY)

  			xfs_force_shutdown(tp->t_mountp, SHUTDOWN_META_IO_ERROR);

  		xfs_buf_relse(bp);
  		return error;
  	}
  #ifdef DEBUG
  	if (xfs_do_error && !(tp->t_flags & XFS_TRANS_DIRTY)) {
  		if (xfs_error_target == target) {
  			if (((xfs_req_num++) % xfs_error_mod) == 0) {
  				xfs_force_shutdown(tp->t_mountp,

  						   SHUTDOWN_META_IO_ERROR);

  				xfs_buf_relse(bp);

  				xfs_debug(mp, "Returning trans error!");

  				return XFS_ERROR(EIO);
  			}
  		}
  	}
  #endif
  	if (XFS_FORCED_SHUTDOWN(mp))
  		goto shutdown_abort;

  	_xfs_trans_bjoin(tp, bp, 1);
  	trace_xfs_trans_read_buf(bp->b_fspriv);

  	*bpp = bp;
  	return 0;
  
  shutdown_abort:
  	/*
  	 * the theory here is that buffer is good but we're
  	 * bailing out because the filesystem is being forcibly
  	 * shut down.  So we should leave the b_flags alone since
  	 * the buffer's not staled and just get out.
  	 */
  #if defined(DEBUG)
  	if (XFS_BUF_ISSTALE(bp) && XFS_BUF_ISDELAYWRITE(bp))

  		xfs_notice(mp, "about to pop assert, bp == 0x%p", bp);

  #endif

  	ASSERT((bp->b_flags & (XBF_STALE|XBF_DELWRI)) !=

  				     (XBF_STALE|XBF_DELWRI));

  	trace_xfs_trans_read_buf_shut(bp, _RET_IP_);

  	xfs_buf_relse(bp);
  	*bpp = NULL;
  	return XFS_ERROR(EIO);
  }
  
  
  /*
   * Release the buffer bp which was previously acquired with one of the
   * xfs_trans_... buffer allocation routines if the buffer has not
   * been modified within this transaction.  If the buffer is modified
   * within this transaction, do decrement the recursion count but do
   * not release the buffer even if the count goes to 0.  If the buffer is not
   * modified within the transaction, decrement the recursion count and
   * release the buffer if the recursion count goes to 0.
   *
   * If the buffer is to be released and it was not modified before
   * this transaction began, then free the buf_log_item associated with it.
   *
   * If the transaction pointer is NULL, make this just a normal
   * brelse() call.
   */
  void
  xfs_trans_brelse(xfs_trans_t	*tp,
  		 xfs_buf_t	*bp)
  {
  	xfs_buf_log_item_t	*bip;

  
  	/*
  	 * Default to a normal brelse() call if the tp is NULL.
  	 */
  	if (tp == NULL) {

  		struct xfs_log_item	*lip = bp->b_fspriv;

  		ASSERT(bp->b_transp == NULL);

  		/*
  		 * If there's a buf log item attached to the buffer,
  		 * then let the AIL know that the buffer is being
  		 * unlocked.
  		 */

  		if (lip != NULL && lip->li_type == XFS_LI_BUF) {
  			bip = bp->b_fspriv;
  			xfs_trans_unlocked_item(bip->bli_item.li_ailp, lip);

  		}
  		xfs_buf_relse(bp);
  		return;
  	}

  	ASSERT(bp->b_transp == tp);

  	bip = bp->b_fspriv;

  	ASSERT(bip->bli_item.li_type == XFS_LI_BUF);
  	ASSERT(!(bip->bli_flags & XFS_BLI_STALE));

  	ASSERT(!(bip->bli_format.blf_flags & XFS_BLF_CANCEL));

  	ASSERT(atomic_read(&bip->bli_refcount) > 0);

  	trace_xfs_trans_brelse(bip);

  	/*
  	 * If the release is just for a recursive lock,
  	 * then decrement the count and return.
  	 */
  	if (bip->bli_recur > 0) {
  		bip->bli_recur--;

  		return;
  	}
  
  	/*
  	 * If the buffer is dirty within this transaction, we can't
  	 * release it until we commit.
  	 */

  	if (bip->bli_item.li_desc->lid_flags & XFS_LID_DIRTY)

  		return;

  
  	/*
  	 * If the buffer has been invalidated, then we can't release
  	 * it until the transaction commits to disk unless it is re-dirtied
  	 * as part of this transaction.  This prevents us from pulling
  	 * the item from the AIL before we should.
  	 */

  	if (bip->bli_flags & XFS_BLI_STALE)

  		return;

  
  	ASSERT(!(bip->bli_flags & XFS_BLI_LOGGED));

  
  	/*
  	 * Free up the log item descriptor tracking the released item.
  	 */

  	xfs_trans_del_item(&bip->bli_item);

  
  	/*
  	 * Clear the hold flag in the buf log item if it is set.
  	 * We wouldn't want the next user of the buffer to
  	 * get confused.
  	 */
  	if (bip->bli_flags & XFS_BLI_HOLD) {
  		bip->bli_flags &= ~XFS_BLI_HOLD;
  	}
  
  	/*
  	 * Drop our reference to the buf log item.
  	 */
  	atomic_dec(&bip->bli_refcount);
  
  	/*
  	 * If the buf item is not tracking data in the log, then
  	 * we must free it before releasing the buffer back to the
  	 * free pool.  Before releasing the buffer to the free pool,
  	 * clear the transaction pointer in b_fsprivate2 to dissolve
  	 * its relation to this transaction.
  	 */
  	if (!xfs_buf_item_dirty(bip)) {
  /***
  		ASSERT(bp->b_pincount == 0);
  ***/
  		ASSERT(atomic_read(&bip->bli_refcount) == 0);
  		ASSERT(!(bip->bli_item.li_flags & XFS_LI_IN_AIL));
  		ASSERT(!(bip->bli_flags & XFS_BLI_INODE_ALLOC_BUF));
  		xfs_buf_item_relse(bp);
  		bip = NULL;
  	}

  	bp->b_transp = NULL;

  
  	/*
  	 * If we've still got a buf log item on the buffer, then
  	 * tell the AIL that the buffer is being unlocked.
  	 */
  	if (bip != NULL) {

  		xfs_trans_unlocked_item(bip->bli_item.li_ailp,

  					(xfs_log_item_t*)bip);
  	}
  
  	xfs_buf_relse(bp);
  	return;
  }
  
  /*

   * Mark the buffer as not needing to be unlocked when the buf item's
   * IOP_UNLOCK() routine is called.  The buffer must already be locked
   * and associated with the given transaction.
   */
  /* ARGSUSED */
  void
  xfs_trans_bhold(xfs_trans_t	*tp,
  		xfs_buf_t	*bp)
  {

  	xfs_buf_log_item_t	*bip = bp->b_fspriv;

  	ASSERT(bp->b_transp == tp);

  	ASSERT(bip != NULL);

  	ASSERT(!(bip->bli_flags & XFS_BLI_STALE));

  	ASSERT(!(bip->bli_format.blf_flags & XFS_BLF_CANCEL));

  	ASSERT(atomic_read(&bip->bli_refcount) > 0);

  	bip->bli_flags |= XFS_BLI_HOLD;

  	trace_xfs_trans_bhold(bip);

  }
  
  /*

   * Cancel the previous buffer hold request made on this buffer
   * for this transaction.
   */
  void
  xfs_trans_bhold_release(xfs_trans_t	*tp,
  			xfs_buf_t	*bp)
  {

  	xfs_buf_log_item_t	*bip = bp->b_fspriv;

  	ASSERT(bp->b_transp == tp);

  	ASSERT(bip != NULL);

  	ASSERT(!(bip->bli_flags & XFS_BLI_STALE));

  	ASSERT(!(bip->bli_format.blf_flags & XFS_BLF_CANCEL));

  	ASSERT(atomic_read(&bip->bli_refcount) > 0);
  	ASSERT(bip->bli_flags & XFS_BLI_HOLD);

  	bip->bli_flags &= ~XFS_BLI_HOLD;

  	trace_xfs_trans_bhold_release(bip);

  }
  
  /*

   * This is called to mark bytes first through last inclusive of the given
   * buffer as needing to be logged when the transaction is committed.
   * The buffer must already be associated with the given transaction.
   *
   * First and last are numbers relative to the beginning of this buffer,
   * so the first byte in the buffer is numbered 0 regardless of the
   * value of b_blkno.
   */
  void
  xfs_trans_log_buf(xfs_trans_t	*tp,
  		  xfs_buf_t	*bp,
  		  uint		first,
  		  uint		last)
  {

  	xfs_buf_log_item_t	*bip = bp->b_fspriv;

  	ASSERT(bp->b_transp == tp);

  	ASSERT(bip != NULL);

  	ASSERT((first <= last) && (last < XFS_BUF_COUNT(bp)));

  	ASSERT(bp->b_iodone == NULL ||
  	       bp->b_iodone == xfs_buf_iodone_callbacks);

  
  	/*
  	 * Mark the buffer as needing to be written out eventually,
  	 * and set its iodone function to remove the buffer's buf log
  	 * item from the AIL and free it when the buffer is flushed
  	 * to disk.  See xfs_buf_attach_iodone() for more details
  	 * on li_cb and xfs_buf_iodone_callbacks().
  	 * If we end up aborting this transaction, we trap this buffer
  	 * inside the b_bdstrat callback so that this won't get written to
  	 * disk.
  	 */

  	XFS_BUF_DONE(bp);

  	ASSERT(atomic_read(&bip->bli_refcount) > 0);

  	bp->b_iodone = xfs_buf_iodone_callbacks;

  	bip->bli_item.li_cb = xfs_buf_iodone;

  	xfs_buf_delwri_queue(bp);

  	trace_xfs_trans_log_buf(bip);

  	/*
  	 * If we invalidated the buffer within this transaction, then
  	 * cancel the invalidation now that we're dirtying the buffer
  	 * again.  There are no races with the code in xfs_buf_item_unpin(),
  	 * because we have a reference to the buffer this entire time.
  	 */
  	if (bip->bli_flags & XFS_BLI_STALE) {

  		bip->bli_flags &= ~XFS_BLI_STALE;
  		ASSERT(XFS_BUF_ISSTALE(bp));
  		XFS_BUF_UNSTALE(bp);

  		bip->bli_format.blf_flags &= ~XFS_BLF_CANCEL;

  	}

  	tp->t_flags |= XFS_TRANS_DIRTY;

  	bip->bli_item.li_desc->lid_flags |= XFS_LID_DIRTY;

  	bip->bli_flags |= XFS_BLI_LOGGED;
  	xfs_buf_item_log(bip, first, last);

  }
  
  
  /*
   * This called to invalidate a buffer that is being used within
   * a transaction.  Typically this is because the blocks in the
   * buffer are being freed, so we need to prevent it from being
   * written out when we're done.  Allowing it to be written again
   * might overwrite data in the free blocks if they are reallocated
   * to a file.
   *
   * We prevent the buffer from being written out by clearing the
   * B_DELWRI flag.  We can't always
   * get rid of the buf log item at this point, though, because
   * the buffer may still be pinned by another transaction.  If that
   * is the case, then we'll wait until the buffer is committed to
   * disk for the last time (we can tell by the ref count) and
   * free it in xfs_buf_item_unpin().  Until it is cleaned up we
   * will keep the buffer locked so that the buffer and buf log item
   * are not reused.
   */
  void
  xfs_trans_binval(
  	xfs_trans_t	*tp,
  	xfs_buf_t	*bp)
  {

  	xfs_buf_log_item_t	*bip = bp->b_fspriv;

  	ASSERT(bp->b_transp == tp);

  	ASSERT(bip != NULL);

  	ASSERT(atomic_read(&bip->bli_refcount) > 0);

  	trace_xfs_trans_binval(bip);

  	if (bip->bli_flags & XFS_BLI_STALE) {
  		/*
  		 * If the buffer is already invalidated, then
  		 * just return.
  		 */
  		ASSERT(!(XFS_BUF_ISDELAYWRITE(bp)));
  		ASSERT(XFS_BUF_ISSTALE(bp));
  		ASSERT(!(bip->bli_flags & (XFS_BLI_LOGGED | XFS_BLI_DIRTY)));

  		ASSERT(!(bip->bli_format.blf_flags & XFS_BLF_INODE_BUF));
  		ASSERT(bip->bli_format.blf_flags & XFS_BLF_CANCEL);

  		ASSERT(bip->bli_item.li_desc->lid_flags & XFS_LID_DIRTY);

  		ASSERT(tp->t_flags & XFS_TRANS_DIRTY);

  		return;
  	}
  
  	/*
  	 * Clear the dirty bit in the buffer and set the STALE flag
  	 * in the buf log item.  The STALE flag will be used in
  	 * xfs_buf_item_unpin() to determine if it should clean up
  	 * when the last reference to the buf item is given up.

  	 * We set the XFS_BLF_CANCEL flag in the buf log format structure

  	 * and log the buf item.  This will be used at recovery time
  	 * to determine that copies of the buffer in the log before
  	 * this should not be replayed.
  	 * We mark the item descriptor and the transaction dirty so
  	 * that we'll hold the buffer until after the commit.
  	 *
  	 * Since we're invalidating the buffer, we also clear the state
  	 * about which parts of the buffer have been logged.  We also
  	 * clear the flag indicating that this is an inode buffer since
  	 * the data in the buffer will no longer be valid.
  	 *
  	 * We set the stale bit in the buffer as well since we're getting
  	 * rid of it.
  	 */

  	xfs_buf_stale(bp);

  	bip->bli_flags |= XFS_BLI_STALE;

  	bip->bli_flags &= ~(XFS_BLI_INODE_BUF | XFS_BLI_LOGGED | XFS_BLI_DIRTY);

  	bip->bli_format.blf_flags &= ~XFS_BLF_INODE_BUF;
  	bip->bli_format.blf_flags |= XFS_BLF_CANCEL;

  	memset((char *)(bip->bli_format.blf_data_map), 0,
  	      (bip->bli_format.blf_map_size * sizeof(uint)));

  	bip->bli_item.li_desc->lid_flags |= XFS_LID_DIRTY;

  	tp->t_flags |= XFS_TRANS_DIRTY;

  }
  
  /*

   * This call is used to indicate that the buffer contains on-disk inodes which
   * must be handled specially during recovery.  They require special handling
   * because only the di_next_unlinked from the inodes in the buffer should be
   * recovered.  The rest of the data in the buffer is logged via the inodes
   * themselves.

   *

   * All we do is set the XFS_BLI_INODE_BUF flag in the items flags so it can be
   * transferred to the buffer's log format structure so that we'll know what to
   * do at recovery time.

   */

  void
  xfs_trans_inode_buf(
  	xfs_trans_t	*tp,
  	xfs_buf_t	*bp)
  {

  	xfs_buf_log_item_t	*bip = bp->b_fspriv;

  	ASSERT(bp->b_transp == tp);

  	ASSERT(bip != NULL);

  	ASSERT(atomic_read(&bip->bli_refcount) > 0);

  	bip->bli_flags |= XFS_BLI_INODE_BUF;

  }
  
  /*
   * This call is used to indicate that the buffer is going to
   * be staled and was an inode buffer. This means it gets
   * special processing during unpin - where any inodes 
   * associated with the buffer should be removed from ail.
   * There is also special processing during recovery,
   * any replay of the inodes in the buffer needs to be
   * prevented as the buffer may have been reused.
   */
  void
  xfs_trans_stale_inode_buf(
  	xfs_trans_t	*tp,
  	xfs_buf_t	*bp)
  {

  	xfs_buf_log_item_t	*bip = bp->b_fspriv;

  	ASSERT(bp->b_transp == tp);

  	ASSERT(bip != NULL);

  	ASSERT(atomic_read(&bip->bli_refcount) > 0);
  
  	bip->bli_flags |= XFS_BLI_STALE_INODE;

  	bip->bli_item.li_cb = xfs_buf_iodone;

  }

  /*
   * Mark the buffer as being one which contains newly allocated
   * inodes.  We need to make sure that even if this buffer is
   * relogged as an 'inode buf' we still recover all of the inode
   * images in the face of a crash.  This works in coordination with
   * xfs_buf_item_committed() to ensure that the buffer remains in the
   * AIL at its original location even after it has been relogged.
   */
  /* ARGSUSED */
  void
  xfs_trans_inode_alloc_buf(
  	xfs_trans_t	*tp,
  	xfs_buf_t	*bp)
  {

  	xfs_buf_log_item_t	*bip = bp->b_fspriv;

  	ASSERT(bp->b_transp == tp);

  	ASSERT(bip != NULL);

  	ASSERT(atomic_read(&bip->bli_refcount) > 0);
  
  	bip->bli_flags |= XFS_BLI_INODE_ALLOC_BUF;
  }
  
  
  /*
   * Similar to xfs_trans_inode_buf(), this marks the buffer as a cluster of
   * dquots. However, unlike in inode buffer recovery, dquot buffers get
   * recovered in their entirety. (Hence, no XFS_BLI_DQUOT_ALLOC_BUF flag).
   * The only thing that makes dquot buffers different from regular
   * buffers is that we must not replay dquot bufs when recovering
   * if a _corresponding_ quotaoff has happened. We also have to distinguish
   * between usr dquot bufs and grp dquot bufs, because usr and grp quotas
   * can be turned off independently.
   */
  /* ARGSUSED */
  void
  xfs_trans_dquot_buf(
  	xfs_trans_t	*tp,
  	xfs_buf_t	*bp,
  	uint		type)
  {

  	xfs_buf_log_item_t	*bip = bp->b_fspriv;

  	ASSERT(bp->b_transp == tp);

  	ASSERT(bip != NULL);

  	ASSERT(type == XFS_BLF_UDQUOT_BUF ||
  	       type == XFS_BLF_PDQUOT_BUF ||
  	       type == XFS_BLF_GDQUOT_BUF);

  	ASSERT(atomic_read(&bip->bli_refcount) > 0);
  
  	bip->bli_format.blf_flags |= type;
  }