/*

   * Copyright (c) 2000-2005 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_acl.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_btree.h"
  #include "xfs_ialloc.h"

  #include "xfs_quota.h"
  #include "xfs_utils.h"

  #include "xfs_trans_priv.h"
  #include "xfs_inode_item.h"

  #include "xfs_bmap.h"

  #include "xfs_trace.h"

  
  
  /*

   * Define xfs inode iolock lockdep classes. We need to ensure that all active
   * inodes are considered the same for lockdep purposes, including inodes that
   * are recycled through the XFS_IRECLAIMABLE state. This is the the only way to
   * guarantee the locks are considered the same when there are multiple lock
   * initialisation siteѕ. Also, define a reclaimable inode class so it is
   * obvious in lockdep reports which class the report is against.
   */
  static struct lock_class_key xfs_iolock_active;
  struct lock_class_key xfs_iolock_reclaimable;
  
  /*

   * Allocate and initialise an xfs_inode.
   */
  STATIC struct xfs_inode *
  xfs_inode_alloc(
  	struct xfs_mount	*mp,
  	xfs_ino_t		ino)
  {
  	struct xfs_inode	*ip;
  
  	/*
  	 * if this didn't occur in transactions, we could use
  	 * KM_MAYFAIL and return NULL here on ENOMEM. Set the
  	 * code up to do this anyway.
  	 */
  	ip = kmem_zone_alloc(xfs_inode_zone, KM_SLEEP);
  	if (!ip)
  		return NULL;

  	if (inode_init_always(mp->m_super, VFS_I(ip))) {
  		kmem_zone_free(xfs_inode_zone, ip);
  		return NULL;
  	}

  	ASSERT(atomic_read(&ip->i_pincount) == 0);
  	ASSERT(!spin_is_locked(&ip->i_flags_lock));
  	ASSERT(completion_done(&ip->i_flush));

  	ASSERT(ip->i_ino == 0);

  
  	mrlock_init(&ip->i_iolock, MRLOCK_BARRIER, "xfsio", ip->i_ino);

  	lockdep_set_class_and_name(&ip->i_iolock.mr_lock,
  			&xfs_iolock_active, "xfs_iolock_active");

  	/* initialise the xfs inode */
  	ip->i_ino = ino;
  	ip->i_mount = mp;
  	memset(&ip->i_imap, 0, sizeof(struct xfs_imap));
  	ip->i_afp = NULL;
  	memset(&ip->i_df, 0, sizeof(xfs_ifork_t));
  	ip->i_flags = 0;
  	ip->i_update_core = 0;

  	ip->i_delayed_blks = 0;
  	memset(&ip->i_d, 0, sizeof(xfs_icdinode_t));
  	ip->i_size = 0;
  	ip->i_new_size = 0;

  	return ip;
  }

  STATIC void
  xfs_inode_free_callback(
  	struct rcu_head		*head)
  {
  	struct inode		*inode = container_of(head, struct inode, i_rcu);
  	struct xfs_inode	*ip = XFS_I(inode);

  	kmem_zone_free(xfs_inode_zone, ip);
  }

  void

  xfs_inode_free(
  	struct xfs_inode	*ip)
  {
  	switch (ip->i_d.di_mode & S_IFMT) {
  	case S_IFREG:
  	case S_IFDIR:
  	case S_IFLNK:
  		xfs_idestroy_fork(ip, XFS_DATA_FORK);
  		break;
  	}
  
  	if (ip->i_afp)
  		xfs_idestroy_fork(ip, XFS_ATTR_FORK);

  	if (ip->i_itemp) {
  		/*
  		 * Only if we are shutting down the fs will we see an
  		 * inode still in the AIL. If it is there, we should remove
  		 * it to prevent a use-after-free from occurring.
  		 */
  		xfs_log_item_t	*lip = &ip->i_itemp->ili_item;
  		struct xfs_ail	*ailp = lip->li_ailp;
  
  		ASSERT(((lip->li_flags & XFS_LI_IN_AIL) == 0) ||
  				       XFS_FORCED_SHUTDOWN(ip->i_mount));
  		if (lip->li_flags & XFS_LI_IN_AIL) {
  			spin_lock(&ailp->xa_lock);
  			if (lip->li_flags & XFS_LI_IN_AIL)
  				xfs_trans_ail_delete(ailp, lip);
  			else
  				spin_unlock(&ailp->xa_lock);
  		}
  		xfs_inode_item_destroy(ip);
  		ip->i_itemp = NULL;
  	}
  
  	/* asserts to verify all state is correct here */

  	ASSERT(atomic_read(&ip->i_pincount) == 0);
  	ASSERT(!spin_is_locked(&ip->i_flags_lock));
  	ASSERT(completion_done(&ip->i_flush));

  	/*
  	 * Because we use RCU freeing we need to ensure the inode always
  	 * appears to be reclaimed with an invalid inode number when in the
  	 * free state. The ip->i_flags_lock provides the barrier against lookup
  	 * races.
  	 */
  	spin_lock(&ip->i_flags_lock);
  	ip->i_flags = XFS_IRECLAIM;
  	ip->i_ino = 0;
  	spin_unlock(&ip->i_flags_lock);

  
  	call_rcu(&VFS_I(ip)->i_rcu, xfs_inode_free_callback);

  }

  /*

   * Check the validity of the inode we just found it the cache

   */

  static int
  xfs_iget_cache_hit(

  	struct xfs_perag	*pag,
  	struct xfs_inode	*ip,

  	xfs_ino_t		ino,

  	int			flags,

  	int			lock_flags) __releases(RCU)

  {

  	struct inode		*inode = VFS_I(ip);

  	struct xfs_mount	*mp = ip->i_mount;

  	int			error;

  	/*
  	 * check for re-use of an inode within an RCU grace period due to the
  	 * radix tree nodes not being updated yet. We monitor for this by
  	 * setting the inode number to zero before freeing the inode structure.
  	 * If the inode has been reallocated and set up, then the inode number
  	 * will not match, so check for that, too.
  	 */

  	spin_lock(&ip->i_flags_lock);

  	if (ip->i_ino != ino) {
  		trace_xfs_iget_skip(ip);
  		XFS_STATS_INC(xs_ig_frecycle);
  		error = EAGAIN;
  		goto out_error;
  	}

  	/*

  	 * If we are racing with another cache hit that is currently
  	 * instantiating this inode or currently recycling it out of
  	 * reclaimabe state, wait for the initialisation to complete
  	 * before continuing.
  	 *
  	 * XXX(hch): eventually we should do something equivalent to
  	 *	     wait_on_inode to wait for these flags to be cleared
  	 *	     instead of polling for it.

  	 */

  	if (ip->i_flags & (XFS_INEW|XFS_IRECLAIM)) {

  		trace_xfs_iget_skip(ip);

  		XFS_STATS_INC(xs_ig_frecycle);

  		error = EAGAIN;

  		goto out_error;
  	}

  	/*
  	 * If lookup is racing with unlink return an error immediately.
  	 */
  	if (ip->i_d.di_mode == 0 && !(flags & XFS_IGET_CREATE)) {
  		error = ENOENT;
  		goto out_error;
  	}

  	/*
  	 * If IRECLAIMABLE is set, we've torn down the VFS inode already.
  	 * Need to carefully get it back into useable state.
  	 */
  	if (ip->i_flags & XFS_IRECLAIMABLE) {

  		trace_xfs_iget_reclaim(ip);

  		/*

  		 * We need to set XFS_IRECLAIM to prevent xfs_reclaim_inode
  		 * from stomping over us while we recycle the inode.  We can't
  		 * clear the radix tree reclaimable tag yet as it requires
  		 * pag_ici_lock to be held exclusive.

  		 */

  		ip->i_flags |= XFS_IRECLAIM;

  
  		spin_unlock(&ip->i_flags_lock);

  		rcu_read_unlock();

  
  		error = -inode_init_always(mp->m_super, inode);
  		if (error) {
  			/*
  			 * Re-initializing the inode failed, and we are in deep
  			 * trouble.  Try to re-add it to the reclaim list.
  			 */

  			rcu_read_lock();

  			spin_lock(&ip->i_flags_lock);

  			ip->i_flags &= ~(XFS_INEW | XFS_IRECLAIM);
  			ASSERT(ip->i_flags & XFS_IRECLAIMABLE);

  			trace_xfs_iget_reclaim_fail(ip);

  			goto out_error;

  		}

  		spin_lock(&pag->pag_ici_lock);

  		spin_lock(&ip->i_flags_lock);

  
  		/*
  		 * Clear the per-lifetime state in the inode as we are now
  		 * effectively a new inode and need to return to the initial
  		 * state before reuse occurs.
  		 */
  		ip->i_flags &= ~XFS_IRECLAIM_RESET_FLAGS;

  		ip->i_flags |= XFS_INEW;
  		__xfs_inode_clear_reclaim_tag(mp, pag, ip);

  		inode->i_state = I_NEW;

  
  		ASSERT(!rwsem_is_locked(&ip->i_iolock.mr_lock));
  		mrlock_init(&ip->i_iolock, MRLOCK_BARRIER, "xfsio", ip->i_ino);
  		lockdep_set_class_and_name(&ip->i_iolock.mr_lock,
  				&xfs_iolock_active, "xfs_iolock_active");

  		spin_unlock(&ip->i_flags_lock);

  		spin_unlock(&pag->pag_ici_lock);

  	} else {

  		/* If the VFS inode is being torn down, pause and try again. */

  		if (!igrab(inode)) {

  			trace_xfs_iget_skip(ip);

  			error = EAGAIN;
  			goto out_error;
  		}

  		/* We've got a live one. */
  		spin_unlock(&ip->i_flags_lock);

  		rcu_read_unlock();

  		trace_xfs_iget_hit(ip);

  	}

  	if (lock_flags != 0)
  		xfs_ilock(ip, lock_flags);

  	xfs_iflags_clear(ip, XFS_ISTALE);

  	XFS_STATS_INC(xs_ig_found);

  	return 0;

  out_error:

  	spin_unlock(&ip->i_flags_lock);

  	rcu_read_unlock();

  	return error;
  }
  
  
  static int
  xfs_iget_cache_miss(
  	struct xfs_mount	*mp,
  	struct xfs_perag	*pag,
  	xfs_trans_t		*tp,
  	xfs_ino_t		ino,
  	struct xfs_inode	**ipp,

  	int			flags,

  	int			lock_flags)

  {
  	struct xfs_inode	*ip;
  	int			error;

  	xfs_agino_t		agino = XFS_INO_TO_AGINO(mp, ino);

  	ip = xfs_inode_alloc(mp, ino);
  	if (!ip)
  		return ENOMEM;

  	error = xfs_iread(mp, tp, ip, flags);

  	if (error)

  		goto out_destroy;

  	trace_xfs_iget_miss(ip);

  	if ((ip->i_d.di_mode == 0) && !(flags & XFS_IGET_CREATE)) {

  		error = ENOENT;
  		goto out_destroy;

  	}
  
  	/*

  	 * Preload the radix tree so we can insert safely under the

  	 * write spinlock. Note that we cannot sleep inside the preload
  	 * region.

  	 */

  	if (radix_tree_preload(GFP_KERNEL)) {

  		error = EAGAIN;

  		goto out_destroy;
  	}
  
  	/*
  	 * Because the inode hasn't been added to the radix-tree yet it can't
  	 * be found by another thread, so we can do the non-sleeping lock here.
  	 */
  	if (lock_flags) {
  		if (!xfs_ilock_nowait(ip, lock_flags))
  			BUG();

  	}

  	spin_lock(&pag->pag_ici_lock);

  
  	/* insert the new inode */

  	error = radix_tree_insert(&pag->pag_ici_root, agino, ip);
  	if (unlikely(error)) {

  		WARN_ON(error != -EEXIST);

  		XFS_STATS_INC(xs_ig_dup);

  		error = EAGAIN;

  		goto out_preload_end;

  	}

  	/* These values _must_ be set before releasing the radix tree lock! */

  	ip->i_udquot = ip->i_gdquot = NULL;

  	xfs_iflags_set(ip, XFS_INEW);

  	spin_unlock(&pag->pag_ici_lock);

  	radix_tree_preload_end();

  	*ipp = ip;
  	return 0;

  out_preload_end:

  	spin_unlock(&pag->pag_ici_lock);

  	radix_tree_preload_end();

  	if (lock_flags)
  		xfs_iunlock(ip, lock_flags);

  out_destroy:

  	__destroy_inode(VFS_I(ip));
  	xfs_inode_free(ip);

  	return error;
  }
  
  /*
   * Look up an inode by number in the given file system.
   * The inode is looked up in the cache held in each AG.

   * If the inode is found in the cache, initialise the vfs inode
   * if necessary.

   *
   * If it is not in core, read it in from the file system's device,

   * add it to the cache and initialise the vfs inode.

   *
   * The inode is locked according to the value of the lock_flags parameter.
   * This flag parameter indicates how and if the inode's IO lock and inode lock
   * should be taken.
   *
   * mp -- the mount point structure for the current file system.  It points
   *       to the inode hash table.
   * tp -- a pointer to the current transaction if there is one.  This is
   *       simply passed through to the xfs_iread() call.
   * ino -- the number of the inode desired.  This is the unique identifier
   *        within the file system for the inode being requested.
   * lock_flags -- flags indicating how to lock the inode.  See the comment
   *		 for xfs_ilock() for a list of valid values.

   */

  int
  xfs_iget(

  	xfs_mount_t	*mp,
  	xfs_trans_t	*tp,
  	xfs_ino_t	ino,
  	uint		flags,
  	uint		lock_flags,

  	xfs_inode_t	**ipp)

  {
  	xfs_inode_t	*ip;
  	int		error;
  	xfs_perag_t	*pag;
  	xfs_agino_t	agino;

  	/* reject inode numbers outside existing AGs */

  	if (!ino || XFS_INO_TO_AGNO(mp, ino) >= mp->m_sb.sb_agcount)

  		return EINVAL;
  
  	/* get the perag structure and ensure that it's inode capable */

  	pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ino));

  	agino = XFS_INO_TO_AGINO(mp, ino);
  
  again:
  	error = 0;

  	rcu_read_lock();

  	ip = radix_tree_lookup(&pag->pag_ici_root, agino);
  
  	if (ip) {

  		error = xfs_iget_cache_hit(pag, ip, ino, flags, lock_flags);

  		if (error)
  			goto out_error_or_again;
  	} else {

  		rcu_read_unlock();

  		XFS_STATS_INC(xs_ig_missed);

  		error = xfs_iget_cache_miss(mp, pag, tp, ino, &ip,

  							flags, lock_flags);
  		if (error)
  			goto out_error_or_again;
  	}

  	xfs_perag_put(pag);

  	*ipp = ip;

  	ASSERT(ip->i_df.if_ext_max ==
  	       XFS_IFORK_DSIZE(ip) / sizeof(xfs_bmbt_rec_t));

  	/*

  	 * If we have a real type for an on-disk inode, we can set ops(&unlock)
  	 * now.	 If it's a new inode being created, xfs_ialloc will handle it.
  	 */

  	if (xfs_iflags_test(ip, XFS_INEW) && ip->i_d.di_mode != 0)

  		xfs_setup_inode(ip);

  	return 0;

  
  out_error_or_again:
  	if (error == EAGAIN) {
  		delay(1);
  		goto again;
  	}

  	xfs_perag_put(pag);

  	return error;

  }

  /*

   * This is a wrapper routine around the xfs_ilock() routine
   * used to centralize some grungy code.  It is used in places
   * that wish to lock the inode solely for reading the extents.
   * The reason these places can't just call xfs_ilock(SHARED)
   * is that the inode lock also guards to bringing in of the
   * extents from disk for a file in b-tree format.  If the inode
   * is in b-tree format, then we need to lock the inode exclusively
   * until the extents are read in.  Locking it exclusively all
   * the time would limit our parallelism unnecessarily, though.
   * What we do instead is check to see if the extents have been
   * read in yet, and only lock the inode exclusively if they
   * have not.
   *
   * The function returns a value which should be given to the
   * corresponding xfs_iunlock_map_shared().  This value is
   * the mode in which the lock was actually taken.
   */
  uint
  xfs_ilock_map_shared(
  	xfs_inode_t	*ip)
  {
  	uint	lock_mode;
  
  	if ((ip->i_d.di_format == XFS_DINODE_FMT_BTREE) &&
  	    ((ip->i_df.if_flags & XFS_IFEXTENTS) == 0)) {
  		lock_mode = XFS_ILOCK_EXCL;
  	} else {
  		lock_mode = XFS_ILOCK_SHARED;
  	}
  
  	xfs_ilock(ip, lock_mode);
  
  	return lock_mode;
  }
  
  /*
   * This is simply the unlock routine to go with xfs_ilock_map_shared().
   * All it does is call xfs_iunlock() with the given lock_mode.
   */
  void
  xfs_iunlock_map_shared(
  	xfs_inode_t	*ip,
  	unsigned int	lock_mode)
  {
  	xfs_iunlock(ip, lock_mode);
  }
  
  /*
   * The xfs inode contains 2 locks: a multi-reader lock called the
   * i_iolock and a multi-reader lock called the i_lock.  This routine
   * allows either or both of the locks to be obtained.
   *
   * The 2 locks should always be ordered so that the IO lock is
   * obtained first in order to prevent deadlock.
   *
   * ip -- the inode being locked
   * lock_flags -- this parameter indicates the inode's locks
   *       to be locked.  It can be:
   *		XFS_IOLOCK_SHARED,
   *		XFS_IOLOCK_EXCL,
   *		XFS_ILOCK_SHARED,
   *		XFS_ILOCK_EXCL,
   *		XFS_IOLOCK_SHARED | XFS_ILOCK_SHARED,
   *		XFS_IOLOCK_SHARED | XFS_ILOCK_EXCL,
   *		XFS_IOLOCK_EXCL | XFS_ILOCK_SHARED,
   *		XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL
   */
  void

  xfs_ilock(
  	xfs_inode_t		*ip,
  	uint			lock_flags)

  {
  	/*
  	 * You can't set both SHARED and EXCL for the same lock,
  	 * and only XFS_IOLOCK_SHARED, XFS_IOLOCK_EXCL, XFS_ILOCK_SHARED,
  	 * and XFS_ILOCK_EXCL are valid values to set in lock_flags.
  	 */
  	ASSERT((lock_flags & (XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL)) !=
  	       (XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL));
  	ASSERT((lock_flags & (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)) !=
  	       (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL));

  	ASSERT((lock_flags & ~(XFS_LOCK_MASK | XFS_LOCK_DEP_MASK)) == 0);

  	if (lock_flags & XFS_IOLOCK_EXCL)

  		mrupdate_nested(&ip->i_iolock, XFS_IOLOCK_DEP(lock_flags));

  	else if (lock_flags & XFS_IOLOCK_SHARED)

  		mraccess_nested(&ip->i_iolock, XFS_IOLOCK_DEP(lock_flags));

  
  	if (lock_flags & XFS_ILOCK_EXCL)

  		mrupdate_nested(&ip->i_lock, XFS_ILOCK_DEP(lock_flags));

  	else if (lock_flags & XFS_ILOCK_SHARED)

  		mraccess_nested(&ip->i_lock, XFS_ILOCK_DEP(lock_flags));

  	trace_xfs_ilock(ip, lock_flags, _RET_IP_);

  }
  
  /*
   * This is just like xfs_ilock(), except that the caller
   * is guaranteed not to sleep.  It returns 1 if it gets
   * the requested locks and 0 otherwise.  If the IO lock is
   * obtained but the inode lock cannot be, then the IO lock
   * is dropped before returning.
   *
   * ip -- the inode being locked
   * lock_flags -- this parameter indicates the inode's locks to be
   *       to be locked.  See the comment for xfs_ilock() for a list
   *	 of valid values.

   */
  int

  xfs_ilock_nowait(
  	xfs_inode_t		*ip,
  	uint			lock_flags)

  {

  	/*
  	 * You can't set both SHARED and EXCL for the same lock,
  	 * and only XFS_IOLOCK_SHARED, XFS_IOLOCK_EXCL, XFS_ILOCK_SHARED,
  	 * and XFS_ILOCK_EXCL are valid values to set in lock_flags.
  	 */
  	ASSERT((lock_flags & (XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL)) !=
  	       (XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL));
  	ASSERT((lock_flags & (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)) !=
  	       (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL));

  	ASSERT((lock_flags & ~(XFS_LOCK_MASK | XFS_LOCK_DEP_MASK)) == 0);

  	if (lock_flags & XFS_IOLOCK_EXCL) {

  		if (!mrtryupdate(&ip->i_iolock))
  			goto out;

  	} else if (lock_flags & XFS_IOLOCK_SHARED) {

  		if (!mrtryaccess(&ip->i_iolock))
  			goto out;

  	}
  	if (lock_flags & XFS_ILOCK_EXCL) {

  		if (!mrtryupdate(&ip->i_lock))
  			goto out_undo_iolock;

  	} else if (lock_flags & XFS_ILOCK_SHARED) {

  		if (!mrtryaccess(&ip->i_lock))
  			goto out_undo_iolock;

  	}

  	trace_xfs_ilock_nowait(ip, lock_flags, _RET_IP_);

  	return 1;

  
   out_undo_iolock:
  	if (lock_flags & XFS_IOLOCK_EXCL)
  		mrunlock_excl(&ip->i_iolock);
  	else if (lock_flags & XFS_IOLOCK_SHARED)
  		mrunlock_shared(&ip->i_iolock);
   out:
  	return 0;

  }
  
  /*
   * xfs_iunlock() is used to drop the inode locks acquired with
   * xfs_ilock() and xfs_ilock_nowait().  The caller must pass
   * in the flags given to xfs_ilock() or xfs_ilock_nowait() so
   * that we know which locks to drop.
   *
   * ip -- the inode being unlocked
   * lock_flags -- this parameter indicates the inode's locks to be
   *       to be unlocked.  See the comment for xfs_ilock() for a list
   *	 of valid values for this parameter.
   *
   */
  void

  xfs_iunlock(
  	xfs_inode_t		*ip,
  	uint			lock_flags)

  {
  	/*
  	 * You can't set both SHARED and EXCL for the same lock,
  	 * and only XFS_IOLOCK_SHARED, XFS_IOLOCK_EXCL, XFS_ILOCK_SHARED,
  	 * and XFS_ILOCK_EXCL are valid values to set in lock_flags.
  	 */
  	ASSERT((lock_flags & (XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL)) !=
  	       (XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL));
  	ASSERT((lock_flags & (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)) !=
  	       (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL));

  	ASSERT((lock_flags & ~(XFS_LOCK_MASK | XFS_IUNLOCK_NONOTIFY |
  			XFS_LOCK_DEP_MASK)) == 0);

  	ASSERT(lock_flags != 0);

  	if (lock_flags & XFS_IOLOCK_EXCL)
  		mrunlock_excl(&ip->i_iolock);
  	else if (lock_flags & XFS_IOLOCK_SHARED)
  		mrunlock_shared(&ip->i_iolock);

  	if (lock_flags & XFS_ILOCK_EXCL)
  		mrunlock_excl(&ip->i_lock);
  	else if (lock_flags & XFS_ILOCK_SHARED)
  		mrunlock_shared(&ip->i_lock);

  	if ((lock_flags & (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)) &&
  	    !(lock_flags & XFS_IUNLOCK_NONOTIFY) && ip->i_itemp) {

  		/*
  		 * Let the AIL know that this item has been unlocked in case
  		 * it is in the AIL and anyone is waiting on it.  Don't do
  		 * this if the caller has asked us not to.
  		 */

  		xfs_trans_unlocked_item(ip->i_itemp->ili_item.li_ailp,

  					(xfs_log_item_t*)(ip->i_itemp));

  	}

  	trace_xfs_iunlock(ip, lock_flags, _RET_IP_);

  }
  
  /*
   * give up write locks.  the i/o lock cannot be held nested
   * if it is being demoted.
   */
  void

  xfs_ilock_demote(
  	xfs_inode_t		*ip,
  	uint			lock_flags)

  {
  	ASSERT(lock_flags & (XFS_IOLOCK_EXCL|XFS_ILOCK_EXCL));
  	ASSERT((lock_flags & ~(XFS_IOLOCK_EXCL|XFS_ILOCK_EXCL)) == 0);

  	if (lock_flags & XFS_ILOCK_EXCL)

  		mrdemote(&ip->i_lock);

  	if (lock_flags & XFS_IOLOCK_EXCL)

  		mrdemote(&ip->i_iolock);

  
  	trace_xfs_ilock_demote(ip, lock_flags, _RET_IP_);

  }
  
  #ifdef DEBUG

  int
  xfs_isilocked(
  	xfs_inode_t		*ip,
  	uint			lock_flags)
  {

  	if (lock_flags & (XFS_ILOCK_EXCL|XFS_ILOCK_SHARED)) {
  		if (!(lock_flags & XFS_ILOCK_SHARED))
  			return !!ip->i_lock.mr_writer;
  		return rwsem_is_locked(&ip->i_lock.mr_lock);

  	}

  	if (lock_flags & (XFS_IOLOCK_EXCL|XFS_IOLOCK_SHARED)) {
  		if (!(lock_flags & XFS_IOLOCK_SHARED))
  			return !!ip->i_iolock.mr_writer;
  		return rwsem_is_locked(&ip->i_iolock.mr_lock);

  	}

  	ASSERT(0);
  	return 0;

  }

  #endif