fs/xfs/linux-2.6/xfs_sync.c - kernel/msm - Gitiles

 /*
  * 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_bit.h"
 #include "xfs_log.h"
 #include "xfs_inum.h"
 #include "xfs_trans.h"
 #include "xfs_sb.h"
 #include "xfs_ag.h"
 #include "xfs_dir2.h"
 #include "xfs_dmapi.h"
 #include "xfs_mount.h"
 #include "xfs_bmap_btree.h"
 #include "xfs_alloc_btree.h"
 #include "xfs_ialloc_btree.h"
 #include "xfs_btree.h"
 #include "xfs_dir2_sf.h"
 #include "xfs_attr_sf.h"
 #include "xfs_inode.h"
 #include "xfs_dinode.h"
 #include "xfs_error.h"
 #include "xfs_mru_cache.h"
 #include "xfs_filestream.h"
 #include "xfs_vnodeops.h"
 #include "xfs_utils.h"
 #include "xfs_buf_item.h"
 #include "xfs_inode_item.h"
 #include "xfs_rw.h"
 #include "xfs_quota.h"
 #include "xfs_trace.h"

 #include <linux/kthread.h>
 #include <linux/freezer.h>


 STATIC xfs_inode_t *
 xfs_inode_ag_lookup(
 	struct xfs_mount	*mp,
 	struct xfs_perag	*pag,
 	uint32_t		*first_index,
 	int			tag)
 {
 	int			nr_found;
 	struct xfs_inode	*ip;

 	/*
 	 * use a gang lookup to find the next inode in the tree
 	 * as the tree is sparse and a gang lookup walks to find
 	 * the number of objects requested.
 	 */
 	if (tag == XFS_ICI_NO_TAG) {
 		nr_found = radix_tree_gang_lookup(&pag->pag_ici_root,
 				(void **)&ip, *first_index, 1);
 	} else {
 		nr_found = radix_tree_gang_lookup_tag(&pag->pag_ici_root,
 				(void **)&ip, *first_index, 1, tag);
 	}
 	if (!nr_found)
 		return NULL;

 	/*
 	 * Update the index for the next lookup. Catch overflows
 	 * into the next AG range which can occur if we have inodes
 	 * in the last block of the AG and we are currently
 	 * pointing to the last inode.
 	 */
 	*first_index = XFS_INO_TO_AGINO(mp, ip->i_ino + 1);
 	if (*first_index < XFS_INO_TO_AGINO(mp, ip->i_ino))
 		return NULL;
 	return ip;
 }

 STATIC int
 xfs_inode_ag_walk(
 	struct xfs_mount	*mp,
 	struct xfs_perag	*pag,
 	int			(*execute)(struct xfs_inode *ip,
 					   struct xfs_perag *pag, int flags),
 	int			flags,
 	int			tag,
 	int			exclusive)
 {
 	uint32_t		first_index;
 	int			last_error = 0;
 	int			skipped;

 restart:
 	skipped = 0;
 	first_index = 0;
 	do {
 		int		error = 0;
 		xfs_inode_t	*ip;

 		if (exclusive)
 			write_lock(&pag->pag_ici_lock);
 		else
 			read_lock(&pag->pag_ici_lock);
 		ip = xfs_inode_ag_lookup(mp, pag, &first_index, tag);
 		if (!ip) {
 			if (exclusive)
 				write_unlock(&pag->pag_ici_lock);
 			else
 				read_unlock(&pag->pag_ici_lock);
 			break;
 		}

 		/* execute releases pag->pag_ici_lock */
 		error = execute(ip, pag, flags);
 		if (error == EAGAIN) {
 			skipped++;
 			continue;
 		}
 		if (error)
 			last_error = error;

 		/* bail out if the filesystem is corrupted.  */
 		if (error == EFSCORRUPTED)
 			break;

 	} while (1);

 	if (skipped) {
 		delay(1);
 		goto restart;
 	}
 	return last_error;
 }

 int
 xfs_inode_ag_iterator(
 	struct xfs_mount	*mp,
 	int			(*execute)(struct xfs_inode *ip,
 					   struct xfs_perag *pag, int flags),
 	int			flags,
 	int			tag,
 	int			exclusive)
 {
 	int			error = 0;
 	int			last_error = 0;
 	xfs_agnumber_t		ag;

 	for (ag = 0; ag < mp->m_sb.sb_agcount; ag++) {
 		struct xfs_perag	*pag;

 		pag = xfs_perag_get(mp, ag);
 		if (!pag->pag_ici_init) {
 			xfs_perag_put(pag);
 			continue;
 		}
 		error = xfs_inode_ag_walk(mp, pag, execute, flags, tag,
 						exclusive);
 		xfs_perag_put(pag);
 		if (error) {
 			last_error = error;
 			if (error == EFSCORRUPTED)
 				break;
 		}
 	}
 	return XFS_ERROR(last_error);
 }

 /* must be called with pag_ici_lock held and releases it */
 int
 xfs_sync_inode_valid(
 	struct xfs_inode	*ip,
 	struct xfs_perag	*pag)
 {
 	struct inode		*inode = VFS_I(ip);
 	int			error = EFSCORRUPTED;

 	/* nothing to sync during shutdown */
 	if (XFS_FORCED_SHUTDOWN(ip->i_mount))
 		goto out_unlock;

 	/* avoid new or reclaimable inodes. Leave for reclaim code to flush */
 	error = ENOENT;
 	if (xfs_iflags_test(ip, XFS_INEW | XFS_IRECLAIMABLE | XFS_IRECLAIM))
 		goto out_unlock;

 	/* If we can't grab the inode, it must on it's way to reclaim. */
 	if (!igrab(inode))
 		goto out_unlock;

 	if (is_bad_inode(inode)) {
 		IRELE(ip);
 		goto out_unlock;
 	}

 	/* inode is valid */
 	error = 0;
 out_unlock:
 	read_unlock(&pag->pag_ici_lock);
 	return error;
 }

 STATIC int
 xfs_sync_inode_data(
 	struct xfs_inode	*ip,
 	struct xfs_perag	*pag,
 	int			flags)
 {
 	struct inode		*inode = VFS_I(ip);
 	struct address_space *mapping = inode->i_mapping;
 	int			error = 0;

 	error = xfs_sync_inode_valid(ip, pag);
 	if (error)
 		return error;

 	if (!mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
 		goto out_wait;

 	if (!xfs_ilock_nowait(ip, XFS_IOLOCK_SHARED)) {
 		if (flags & SYNC_TRYLOCK)
 			goto out_wait;
 		xfs_ilock(ip, XFS_IOLOCK_SHARED);
 	}

 	error = xfs_flush_pages(ip, 0, -1, (flags & SYNC_WAIT) ?
 				0 : XFS_B_ASYNC, FI_NONE);
 	xfs_iunlock(ip, XFS_IOLOCK_SHARED);

  out_wait:
 	if (flags & SYNC_WAIT)
 		xfs_ioend_wait(ip);
 	IRELE(ip);
 	return error;
 }

 STATIC int
 xfs_sync_inode_attr(
 	struct xfs_inode	*ip,
 	struct xfs_perag	*pag,
 	int			flags)
 {
 	int			error = 0;

 	error = xfs_sync_inode_valid(ip, pag);
 	if (error)
 		return error;

 	xfs_ilock(ip, XFS_ILOCK_SHARED);
 	if (xfs_inode_clean(ip))
 		goto out_unlock;
 	if (!xfs_iflock_nowait(ip)) {
 		if (!(flags & SYNC_WAIT))
 			goto out_unlock;
 		xfs_iflock(ip);
 	}

 	if (xfs_inode_clean(ip)) {
 		xfs_ifunlock(ip);
 		goto out_unlock;
 	}

 	error = xfs_iflush(ip, (flags & SYNC_WAIT) ?
 			   XFS_IFLUSH_SYNC : XFS_IFLUSH_DELWRI);

  out_unlock:
 	xfs_iunlock(ip, XFS_ILOCK_SHARED);
 	IRELE(ip);
 	return error;
 }

 /*
  * Write out pagecache data for the whole filesystem.
  */
 int
 xfs_sync_data(
 	struct xfs_mount	*mp,
 	int			flags)
 {
 	int			error;

 	ASSERT((flags & ~(SYNC_TRYLOCK|SYNC_WAIT)) == 0);

 	error = xfs_inode_ag_iterator(mp, xfs_sync_inode_data, flags,
 				      XFS_ICI_NO_TAG, 0);
 	if (error)
 		return XFS_ERROR(error);

 	xfs_log_force(mp, 0,
 		      (flags & SYNC_WAIT) ?
 		       XFS_LOG_FORCE | XFS_LOG_SYNC :
 		       XFS_LOG_FORCE);
 	return 0;
 }

 /*
  * Write out inode metadata (attributes) for the whole filesystem.
  */
 int
 xfs_sync_attr(
 	struct xfs_mount	*mp,
 	int			flags)
 {
 	ASSERT((flags & ~SYNC_WAIT) == 0);

 	return xfs_inode_ag_iterator(mp, xfs_sync_inode_attr, flags,
 				     XFS_ICI_NO_TAG, 0);
 }

 STATIC int
 xfs_commit_dummy_trans(
 	struct xfs_mount	*mp,
 	uint			flags)
 {
 	struct xfs_inode	*ip = mp->m_rootip;
 	struct xfs_trans	*tp;
 	int			error;
 	int			log_flags = XFS_LOG_FORCE;

 	if (flags & SYNC_WAIT)
 		log_flags |= XFS_LOG_SYNC;

 	/*
 	 * Put a dummy transaction in the log to tell recovery
 	 * that all others are OK.
 	 */
 	tp = xfs_trans_alloc(mp, XFS_TRANS_DUMMY1);
 	error = xfs_trans_reserve(tp, 0, XFS_ICHANGE_LOG_RES(mp), 0, 0, 0);
 	if (error) {
 		xfs_trans_cancel(tp, 0);
 		return error;
 	}

 	xfs_ilock(ip, XFS_ILOCK_EXCL);

 	xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
 	xfs_trans_ihold(tp, ip);
 	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 	error = xfs_trans_commit(tp, 0);
 	xfs_iunlock(ip, XFS_ILOCK_EXCL);

 	/* the log force ensures this transaction is pushed to disk */
 	xfs_log_force(mp, 0, log_flags);
 	return error;
 }

 STATIC int
 xfs_sync_fsdata(
 	struct xfs_mount	*mp,
 	int			flags)
 {
 	struct xfs_buf		*bp;
 	struct xfs_buf_log_item	*bip;
 	int			error = 0;

 	/*
 	 * If this is xfssyncd() then only sync the superblock if we can
 	 * lock it without sleeping and it is not pinned.
 	 */
 	if (flags & SYNC_TRYLOCK) {
 		ASSERT(!(flags & SYNC_WAIT));

 		bp = xfs_getsb(mp, XFS_BUF_TRYLOCK);
 		if (!bp)
 			goto out;

 		bip = XFS_BUF_FSPRIVATE(bp, struct xfs_buf_log_item *);
 		if (!bip || !xfs_buf_item_dirty(bip) || XFS_BUF_ISPINNED(bp))
 			goto out_brelse;
 	} else {
 		bp = xfs_getsb(mp, 0);

 		/*
 		 * If the buffer is pinned then push on the log so we won't
 		 * get stuck waiting in the write for someone, maybe
 		 * ourselves, to flush the log.
 		 *
 		 * Even though we just pushed the log above, we did not have
 		 * the superblock buffer locked at that point so it can
 		 * become pinned in between there and here.
 		 */
 		if (XFS_BUF_ISPINNED(bp))
 			xfs_log_force(mp, 0, XFS_LOG_FORCE);
 	}


 	if (flags & SYNC_WAIT)
 		XFS_BUF_UNASYNC(bp);
 	else
 		XFS_BUF_ASYNC(bp);

 	error = xfs_bwrite(mp, bp);
 	if (error)
 		return error;

 	/*
 	 * If this is a data integrity sync make sure all pending buffers
 	 * are flushed out for the log coverage check below.
 	 */
 	if (flags & SYNC_WAIT)
 		xfs_flush_buftarg(mp->m_ddev_targp, 1);

 	if (xfs_log_need_covered(mp))
 		error = xfs_commit_dummy_trans(mp, flags);
 	return error;

  out_brelse:
 	xfs_buf_relse(bp);
  out:
 	return error;
 }

 /*
  * When remounting a filesystem read-only or freezing the filesystem, we have
  * two phases to execute. This first phase is syncing the data before we
  * quiesce the filesystem, and the second is flushing all the inodes out after
  * we've waited for all the transactions created by the first phase to
  * complete. The second phase ensures that the inodes are written to their
  * location on disk rather than just existing in transactions in the log. This
  * means after a quiesce there is no log replay required to write the inodes to
  * disk (this is the main difference between a sync and a quiesce).
  */
 /*
  * First stage of freeze - no writers will make progress now we are here,
  * so we flush delwri and delalloc buffers here, then wait for all I/O to
  * complete.  Data is frozen at that point. Metadata is not frozen,
  * transactions can still occur here so don't bother flushing the buftarg
  * because it'll just get dirty again.
  */
 int
 xfs_quiesce_data(
 	struct xfs_mount	*mp)
 {
 	int error;

 	/* push non-blocking */
 	xfs_sync_data(mp, 0);
 	xfs_qm_sync(mp, SYNC_TRYLOCK);

 	/* push and block till complete */
 	xfs_sync_data(mp, SYNC_WAIT);
 	xfs_qm_sync(mp, SYNC_WAIT);

 	/* drop inode references pinned by filestreams */
 	xfs_filestream_flush(mp);

 	/* write superblock and hoover up shutdown errors */
 	error = xfs_sync_fsdata(mp, SYNC_WAIT);

 	/* flush data-only devices */
 	if (mp->m_rtdev_targp)
 		XFS_bflush(mp->m_rtdev_targp);

 	return error;
 }

 STATIC void
 xfs_quiesce_fs(
 	struct xfs_mount	*mp)
 {
 	int	count = 0, pincount;

 	xfs_flush_buftarg(mp->m_ddev_targp, 0);
 	xfs_reclaim_inodes(mp, XFS_IFLUSH_DELWRI_ELSE_ASYNC);

 	/*
 	 * This loop must run at least twice.  The first instance of the loop
 	 * will flush most meta data but that will generate more meta data
 	 * (typically directory updates).  Which then must be flushed and
 	 * logged before we can write the unmount record.
 	 */
 	do {
 		xfs_sync_attr(mp, SYNC_WAIT);
 		pincount = xfs_flush_buftarg(mp->m_ddev_targp, 1);
 		if (!pincount) {
 			delay(50);
 			count++;
 		}
 	} while (count < 2);
 }

 /*
  * Second stage of a quiesce. The data is already synced, now we have to take
  * care of the metadata. New transactions are already blocked, so we need to
  * wait for any remaining transactions to drain out before proceding.
  */
 void
 xfs_quiesce_attr(
 	struct xfs_mount	*mp)
 {
 	int	error = 0;

 	/* wait for all modifications to complete */
 	while (atomic_read(&mp->m_active_trans) > 0)
 		delay(100);

 	/* flush inodes and push all remaining buffers out to disk */
 	xfs_quiesce_fs(mp);

 	/*
 	 * Just warn here till VFS can correctly support
 	 * read-only remount without racing.
 	 */
 	WARN_ON(atomic_read(&mp->m_active_trans) != 0);

 	/* Push the superblock and write an unmount record */
 	error = xfs_log_sbcount(mp, 1);
 	if (error)
 		xfs_fs_cmn_err(CE_WARN, mp,
 				"xfs_attr_quiesce: failed to log sb changes. "
 				"Frozen image may not be consistent.");
 	xfs_log_unmount_write(mp);
 	xfs_unmountfs_writesb(mp);
 }

 /*
  * Enqueue a work item to be picked up by the vfs xfssyncd thread.
  * Doing this has two advantages:
  * - It saves on stack space, which is tight in certain situations
  * - It can be used (with care) as a mechanism to avoid deadlocks.
  * Flushing while allocating in a full filesystem requires both.
  */
 STATIC void
 xfs_syncd_queue_work(
 	struct xfs_mount *mp,
 	void		*data,
 	void		(*syncer)(struct xfs_mount *, void *),
 	struct completion *completion)
 {
 	struct xfs_sync_work *work;

 	work = kmem_alloc(sizeof(struct xfs_sync_work), KM_SLEEP);
 	INIT_LIST_HEAD(&work->w_list);
 	work->w_syncer = syncer;
 	work->w_data = data;
 	work->w_mount = mp;
 	work->w_completion = completion;
 	spin_lock(&mp->m_sync_lock);
 	list_add_tail(&work->w_list, &mp->m_sync_list);
 	spin_unlock(&mp->m_sync_lock);
 	wake_up_process(mp->m_sync_task);
 }

 /*
  * Flush delayed allocate data, attempting to free up reserved space
  * from existing allocations.  At this point a new allocation attempt
  * has failed with ENOSPC and we are in the process of scratching our
  * heads, looking about for more room...
  */
 STATIC void
 xfs_flush_inodes_work(
 	struct xfs_mount *mp,
 	void		*arg)
 {
 	struct inode	*inode = arg;
 	xfs_sync_data(mp, SYNC_TRYLOCK);
 	xfs_sync_data(mp, SYNC_TRYLOCK | SYNC_WAIT);
 	iput(inode);
 }

 void
 xfs_flush_inodes(
 	xfs_inode_t	*ip)
 {
 	struct inode	*inode = VFS_I(ip);
 	DECLARE_COMPLETION_ONSTACK(completion);

 	igrab(inode);
 	xfs_syncd_queue_work(ip->i_mount, inode, xfs_flush_inodes_work, &completion);
 	wait_for_completion(&completion);
 	xfs_log_force(ip->i_mount, (xfs_lsn_t)0, XFS_LOG_FORCE|XFS_LOG_SYNC);
 }

 /*
  * Every sync period we need to unpin all items, reclaim inodes, sync
  * quota and write out the superblock. We might need to cover the log
  * to indicate it is idle.
  */
 STATIC void
 xfs_sync_worker(
 	struct xfs_mount *mp,
 	void		*unused)
 {
 	int		error;

 	if (!(mp->m_flags & XFS_MOUNT_RDONLY)) {
 		xfs_log_force(mp, (xfs_lsn_t)0, XFS_LOG_FORCE);
 		xfs_reclaim_inodes(mp, XFS_IFLUSH_DELWRI_ELSE_ASYNC);
 		/* dgc: errors ignored here */
 		error = xfs_qm_sync(mp, SYNC_TRYLOCK);
 		error = xfs_sync_fsdata(mp, SYNC_TRYLOCK);
 	}
 	mp->m_sync_seq++;
 	wake_up(&mp->m_wait_single_sync_task);
 }

 STATIC int
 xfssyncd(
 	void			*arg)
 {
 	struct xfs_mount	*mp = arg;
 	long			timeleft;
 	xfs_sync_work_t		*work, *n;
 	LIST_HEAD		(tmp);

 	set_freezable();
 	timeleft = xfs_syncd_centisecs * msecs_to_jiffies(10);
 	for (;;) {
 		timeleft = schedule_timeout_interruptible(timeleft);
 		/* swsusp */
 		try_to_freeze();
 		if (kthread_should_stop() && list_empty(&mp->m_sync_list))
 			break;

 		spin_lock(&mp->m_sync_lock);
 		/*
 		 * We can get woken by laptop mode, to do a sync -
 		 * that's the (only!) case where the list would be
 		 * empty with time remaining.
 		 */
 		if (!timeleft || list_empty(&mp->m_sync_list)) {
 			if (!timeleft)
 				timeleft = xfs_syncd_centisecs *
 							msecs_to_jiffies(10);
 			INIT_LIST_HEAD(&mp->m_sync_work.w_list);
 			list_add_tail(&mp->m_sync_work.w_list,
 					&mp->m_sync_list);
 		}
 		list_for_each_entry_safe(work, n, &mp->m_sync_list, w_list)
 			list_move(&work->w_list, &tmp);
 		spin_unlock(&mp->m_sync_lock);

 		list_for_each_entry_safe(work, n, &tmp, w_list) {
 			(*work->w_syncer)(mp, work->w_data);
 			list_del(&work->w_list);
 			if (work == &mp->m_sync_work)
 				continue;
 			if (work->w_completion)
 				complete(work->w_completion);
 			kmem_free(work);
 		}
 	}

 	return 0;
 }

 int
 xfs_syncd_init(
 	struct xfs_mount	*mp)
 {
 	mp->m_sync_work.w_syncer = xfs_sync_worker;
 	mp->m_sync_work.w_mount = mp;
 	mp->m_sync_work.w_completion = NULL;
 	mp->m_sync_task = kthread_run(xfssyncd, mp, "xfssyncd");
 	if (IS_ERR(mp->m_sync_task))
 		return -PTR_ERR(mp->m_sync_task);
 	return 0;
 }

 void
 xfs_syncd_stop(
 	struct xfs_mount	*mp)
 {
 	kthread_stop(mp->m_sync_task);
 }

 void
 __xfs_inode_set_reclaim_tag(
 	struct xfs_perag	*pag,
 	struct xfs_inode	*ip)
 {
 	radix_tree_tag_set(&pag->pag_ici_root,
 			   XFS_INO_TO_AGINO(ip->i_mount, ip->i_ino),
 			   XFS_ICI_RECLAIM_TAG);
 }

 /*
  * We set the inode flag atomically with the radix tree tag.
  * Once we get tag lookups on the radix tree, this inode flag
  * can go away.
  */
 void
 xfs_inode_set_reclaim_tag(
 	xfs_inode_t	*ip)
 {
 	struct xfs_mount *mp = ip->i_mount;
 	struct xfs_perag *pag;

 	pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
 	read_lock(&pag->pag_ici_lock);
 	spin_lock(&ip->i_flags_lock);
 	__xfs_inode_set_reclaim_tag(pag, ip);
 	__xfs_iflags_set(ip, XFS_IRECLAIMABLE);
 	spin_unlock(&ip->i_flags_lock);
 	read_unlock(&pag->pag_ici_lock);
 	xfs_perag_put(pag);
 }

 void
 __xfs_inode_clear_reclaim_tag(
 	xfs_mount_t	*mp,
 	xfs_perag_t	*pag,
 	xfs_inode_t	*ip)
 {
 	radix_tree_tag_clear(&pag->pag_ici_root,
 			XFS_INO_TO_AGINO(mp, ip->i_ino), XFS_ICI_RECLAIM_TAG);
 }

 STATIC int
 xfs_reclaim_inode(
 	struct xfs_inode	*ip,
 	struct xfs_perag	*pag,
 	int			sync_mode)
 {
 	/*
 	 * The radix tree lock here protects a thread in xfs_iget from racing
 	 * with us starting reclaim on the inode.  Once we have the
 	 * XFS_IRECLAIM flag set it will not touch us.
 	 */
 	spin_lock(&ip->i_flags_lock);
 	ASSERT_ALWAYS(__xfs_iflags_test(ip, XFS_IRECLAIMABLE));
 	if (__xfs_iflags_test(ip, XFS_IRECLAIM)) {
 		/* ignore as it is already under reclaim */
 		spin_unlock(&ip->i_flags_lock);
 		write_unlock(&pag->pag_ici_lock);
 		return 0;
 	}
 	__xfs_iflags_set(ip, XFS_IRECLAIM);
 	spin_unlock(&ip->i_flags_lock);
 	write_unlock(&pag->pag_ici_lock);

 	/*
 	 * If the inode is still dirty, then flush it out.  If the inode
 	 * is not in the AIL, then it will be OK to flush it delwri as
 	 * long as xfs_iflush() does not keep any references to the inode.
 	 * We leave that decision up to xfs_iflush() since it has the
 	 * knowledge of whether it's OK to simply do a delwri flush of
 	 * the inode or whether we need to wait until the inode is
 	 * pulled from the AIL.
 	 * We get the flush lock regardless, though, just to make sure
 	 * we don't free it while it is being flushed.
 	 */
 	xfs_ilock(ip, XFS_ILOCK_EXCL);
 	xfs_iflock(ip);

 	/*
 	 * In the case of a forced shutdown we rely on xfs_iflush() to
 	 * wait for the inode to be unpinned before returning an error.
 	 */
 	if (!is_bad_inode(VFS_I(ip)) && xfs_iflush(ip, sync_mode) == 0) {
 		/* synchronize with xfs_iflush_done */
 		xfs_iflock(ip);
 		xfs_ifunlock(ip);
 	}

 	xfs_iunlock(ip, XFS_ILOCK_EXCL);
 	xfs_ireclaim(ip);
 	return 0;
 }

 int
 xfs_reclaim_inodes(
 	xfs_mount_t	*mp,
 	int		mode)
 {
 	return xfs_inode_ag_iterator(mp, xfs_reclaim_inode, mode,
 					XFS_ICI_RECLAIM_TAG, 1);
 }
	/*
	* 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_bit.h"
	#include "xfs_log.h"
	#include "xfs_inum.h"
	#include "xfs_trans.h"
	#include "xfs_sb.h"
	#include "xfs_ag.h"
	#include "xfs_dir2.h"
	#include "xfs_dmapi.h"
	#include "xfs_mount.h"
	#include "xfs_bmap_btree.h"
	#include "xfs_alloc_btree.h"
	#include "xfs_ialloc_btree.h"
	#include "xfs_btree.h"
	#include "xfs_dir2_sf.h"
	#include "xfs_attr_sf.h"
	#include "xfs_inode.h"
	#include "xfs_dinode.h"
	#include "xfs_error.h"
	#include "xfs_mru_cache.h"
	#include "xfs_filestream.h"
	#include "xfs_vnodeops.h"
	#include "xfs_utils.h"
	#include "xfs_buf_item.h"
	#include "xfs_inode_item.h"
	#include "xfs_rw.h"
	#include "xfs_quota.h"
	#include "xfs_trace.h"

	#include <linux/kthread.h>
	#include <linux/freezer.h>


	STATIC xfs_inode_t *
	xfs_inode_ag_lookup(
	struct xfs_mount *mp,
	struct xfs_perag *pag,
	uint32_t *first_index,
	int tag)
	{
	int nr_found;
	struct xfs_inode *ip;

	/*
	* use a gang lookup to find the next inode in the tree
	* as the tree is sparse and a gang lookup walks to find
	* the number of objects requested.
	*/
	if (tag == XFS_ICI_NO_TAG) {
	nr_found = radix_tree_gang_lookup(&pag->pag_ici_root,
	(void *)&ip, first_index, 1);
	} else {
	nr_found = radix_tree_gang_lookup_tag(&pag->pag_ici_root,
	(void *)&ip, first_index, 1, tag);
	}
	if (!nr_found)
	return NULL;

	/*
	* Update the index for the next lookup. Catch overflows
	* into the next AG range which can occur if we have inodes
	* in the last block of the AG and we are currently
	* pointing to the last inode.
	*/
	*first_index = XFS_INO_TO_AGINO(mp, ip->i_ino + 1);
	if (*first_index < XFS_INO_TO_AGINO(mp, ip->i_ino))
	return NULL;
	return ip;
	}

	STATIC int
	xfs_inode_ag_walk(
	struct xfs_mount *mp,
	struct xfs_perag *pag,
	int (execute)(struct xfs_inode ip,
	struct xfs_perag *pag, int flags),
	int flags,
	int tag,
	int exclusive)
	{
	uint32_t first_index;
	int last_error = 0;
	int skipped;

	restart:
	skipped = 0;
	first_index = 0;
	do {
	int error = 0;
	xfs_inode_t *ip;

	if (exclusive)
	write_lock(&pag->pag_ici_lock);
	else
	read_lock(&pag->pag_ici_lock);
	ip = xfs_inode_ag_lookup(mp, pag, &first_index, tag);
	if (!ip) {
	if (exclusive)
	write_unlock(&pag->pag_ici_lock);
	else
	read_unlock(&pag->pag_ici_lock);
	break;
	}

	/* execute releases pag->pag_ici_lock */
	error = execute(ip, pag, flags);
	if (error == EAGAIN) {
	skipped++;
	continue;
	}
	if (error)
	last_error = error;

	/* bail out if the filesystem is corrupted. */
	if (error == EFSCORRUPTED)
	break;

	} while (1);

	if (skipped) {
	delay(1);
	goto restart;
	}
	return last_error;
	}

	int
	xfs_inode_ag_iterator(
	struct xfs_mount *mp,
	int (execute)(struct xfs_inode ip,
	struct xfs_perag *pag, int flags),
	int flags,
	int tag,
	int exclusive)
	{
	int error = 0;
	int last_error = 0;
	xfs_agnumber_t ag;

	for (ag = 0; ag < mp->m_sb.sb_agcount; ag++) {
	struct xfs_perag *pag;

	pag = xfs_perag_get(mp, ag);
	if (!pag->pag_ici_init) {
	xfs_perag_put(pag);
	continue;
	}
	error = xfs_inode_ag_walk(mp, pag, execute, flags, tag,
	exclusive);
	xfs_perag_put(pag);
	if (error) {
	last_error = error;
	if (error == EFSCORRUPTED)
	break;
	}
	}
	return XFS_ERROR(last_error);
	}

	/* must be called with pag_ici_lock held and releases it */
	int
	xfs_sync_inode_valid(
	struct xfs_inode *ip,
	struct xfs_perag *pag)
	{
	struct inode *inode = VFS_I(ip);
	int error = EFSCORRUPTED;

	/* nothing to sync during shutdown */
	if (XFS_FORCED_SHUTDOWN(ip->i_mount))
	goto out_unlock;

	/* avoid new or reclaimable inodes. Leave for reclaim code to flush */
	error = ENOENT;
	if (xfs_iflags_test(ip, XFS_INEW \| XFS_IRECLAIMABLE \| XFS_IRECLAIM))
	goto out_unlock;

	/* If we can't grab the inode, it must on it's way to reclaim. */
	if (!igrab(inode))
	goto out_unlock;

	if (is_bad_inode(inode)) {
	IRELE(ip);
	goto out_unlock;
	}

	/* inode is valid */
	error = 0;
	out_unlock:
	read_unlock(&pag->pag_ici_lock);
	return error;
	}

	STATIC int
	xfs_sync_inode_data(
	struct xfs_inode *ip,
	struct xfs_perag *pag,
	int flags)
	{
	struct inode *inode = VFS_I(ip);
	struct address_space *mapping = inode->i_mapping;
	int error = 0;

	error = xfs_sync_inode_valid(ip, pag);
	if (error)
	return error;

	if (!mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
	goto out_wait;

	if (!xfs_ilock_nowait(ip, XFS_IOLOCK_SHARED)) {
	if (flags & SYNC_TRYLOCK)
	goto out_wait;
	xfs_ilock(ip, XFS_IOLOCK_SHARED);
	}

	error = xfs_flush_pages(ip, 0, -1, (flags & SYNC_WAIT) ?
	0 : XFS_B_ASYNC, FI_NONE);
	xfs_iunlock(ip, XFS_IOLOCK_SHARED);

	out_wait:
	if (flags & SYNC_WAIT)
	xfs_ioend_wait(ip);
	IRELE(ip);
	return error;
	}

	STATIC int
	xfs_sync_inode_attr(
	struct xfs_inode *ip,
	struct xfs_perag *pag,
	int flags)
	{
	int error = 0;

	error = xfs_sync_inode_valid(ip, pag);
	if (error)
	return error;

	xfs_ilock(ip, XFS_ILOCK_SHARED);
	if (xfs_inode_clean(ip))
	goto out_unlock;
	if (!xfs_iflock_nowait(ip)) {
	if (!(flags & SYNC_WAIT))
	goto out_unlock;
	xfs_iflock(ip);
	}

	if (xfs_inode_clean(ip)) {
	xfs_ifunlock(ip);
	goto out_unlock;
	}

	error = xfs_iflush(ip, (flags & SYNC_WAIT) ?
	XFS_IFLUSH_SYNC : XFS_IFLUSH_DELWRI);

	out_unlock:
	xfs_iunlock(ip, XFS_ILOCK_SHARED);
	IRELE(ip);
	return error;
	}

	/*
	* Write out pagecache data for the whole filesystem.
	*/
	int
	xfs_sync_data(
	struct xfs_mount *mp,
	int flags)
	{
	int error;

	ASSERT((flags & ~(SYNC_TRYLOCK\|SYNC_WAIT)) == 0);

	error = xfs_inode_ag_iterator(mp, xfs_sync_inode_data, flags,
	XFS_ICI_NO_TAG, 0);
	if (error)
	return XFS_ERROR(error);

	xfs_log_force(mp, 0,
	(flags & SYNC_WAIT) ?
	XFS_LOG_FORCE \| XFS_LOG_SYNC :
	XFS_LOG_FORCE);
	return 0;
	}

	/*
	* Write out inode metadata (attributes) for the whole filesystem.
	*/
	int
	xfs_sync_attr(
	struct xfs_mount *mp,
	int flags)
	{
	ASSERT((flags & ~SYNC_WAIT) == 0);

	return xfs_inode_ag_iterator(mp, xfs_sync_inode_attr, flags,
	XFS_ICI_NO_TAG, 0);
	}

	STATIC int
	xfs_commit_dummy_trans(
	struct xfs_mount *mp,
	uint flags)
	{
	struct xfs_inode *ip = mp->m_rootip;
	struct xfs_trans *tp;
	int error;
	int log_flags = XFS_LOG_FORCE;

	if (flags & SYNC_WAIT)
	log_flags \|= XFS_LOG_SYNC;

	/*
	* Put a dummy transaction in the log to tell recovery
	* that all others are OK.
	*/
	tp = xfs_trans_alloc(mp, XFS_TRANS_DUMMY1);
	error = xfs_trans_reserve(tp, 0, XFS_ICHANGE_LOG_RES(mp), 0, 0, 0);
	if (error) {
	xfs_trans_cancel(tp, 0);
	return error;
	}

	xfs_ilock(ip, XFS_ILOCK_EXCL);

	xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
	xfs_trans_ihold(tp, ip);
	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
	error = xfs_trans_commit(tp, 0);
	xfs_iunlock(ip, XFS_ILOCK_EXCL);

	/* the log force ensures this transaction is pushed to disk */
	xfs_log_force(mp, 0, log_flags);
	return error;
	}

	STATIC int
	xfs_sync_fsdata(
	struct xfs_mount *mp,
	int flags)
	{
	struct xfs_buf *bp;
	struct xfs_buf_log_item *bip;
	int error = 0;

	/*
	* If this is xfssyncd() then only sync the superblock if we can
	* lock it without sleeping and it is not pinned.
	*/
	if (flags & SYNC_TRYLOCK) {
	ASSERT(!(flags & SYNC_WAIT));

	bp = xfs_getsb(mp, XFS_BUF_TRYLOCK);
	if (!bp)
	goto out;

	bip = XFS_BUF_FSPRIVATE(bp, struct xfs_buf_log_item *);
	if (!bip \|\| !xfs_buf_item_dirty(bip) \|\| XFS_BUF_ISPINNED(bp))
	goto out_brelse;
	} else {
	bp = xfs_getsb(mp, 0);

	/*
	* If the buffer is pinned then push on the log so we won't
	* get stuck waiting in the write for someone, maybe
	* ourselves, to flush the log.
	*
	* Even though we just pushed the log above, we did not have
	* the superblock buffer locked at that point so it can
	* become pinned in between there and here.
	*/
	if (XFS_BUF_ISPINNED(bp))
	xfs_log_force(mp, 0, XFS_LOG_FORCE);
	}


	if (flags & SYNC_WAIT)
	XFS_BUF_UNASYNC(bp);
	else
	XFS_BUF_ASYNC(bp);

	error = xfs_bwrite(mp, bp);
	if (error)
	return error;

	/*
	* If this is a data integrity sync make sure all pending buffers
	* are flushed out for the log coverage check below.
	*/
	if (flags & SYNC_WAIT)
	xfs_flush_buftarg(mp->m_ddev_targp, 1);

	if (xfs_log_need_covered(mp))
	error = xfs_commit_dummy_trans(mp, flags);
	return error;

	out_brelse:
	xfs_buf_relse(bp);
	out:
	return error;
	}

	/*
	* When remounting a filesystem read-only or freezing the filesystem, we have
	* two phases to execute. This first phase is syncing the data before we
	* quiesce the filesystem, and the second is flushing all the inodes out after
	* we've waited for all the transactions created by the first phase to
	* complete. The second phase ensures that the inodes are written to their
	* location on disk rather than just existing in transactions in the log. This
	* means after a quiesce there is no log replay required to write the inodes to
	* disk (this is the main difference between a sync and a quiesce).
	*/
	/*
	* First stage of freeze - no writers will make progress now we are here,
	* so we flush delwri and delalloc buffers here, then wait for all I/O to
	* complete. Data is frozen at that point. Metadata is not frozen,
	* transactions can still occur here so don't bother flushing the buftarg
	* because it'll just get dirty again.
	*/
	int
	xfs_quiesce_data(
	struct xfs_mount *mp)
	{
	int error;

	/* push non-blocking */
	xfs_sync_data(mp, 0);
	xfs_qm_sync(mp, SYNC_TRYLOCK);

	/* push and block till complete */
	xfs_sync_data(mp, SYNC_WAIT);
	xfs_qm_sync(mp, SYNC_WAIT);

	/* drop inode references pinned by filestreams */
	xfs_filestream_flush(mp);

	/* write superblock and hoover up shutdown errors */
	error = xfs_sync_fsdata(mp, SYNC_WAIT);

	/* flush data-only devices */
	if (mp->m_rtdev_targp)
	XFS_bflush(mp->m_rtdev_targp);

	return error;
	}

	STATIC void
	xfs_quiesce_fs(
	struct xfs_mount *mp)
	{
	int count = 0, pincount;

	xfs_flush_buftarg(mp->m_ddev_targp, 0);
	xfs_reclaim_inodes(mp, XFS_IFLUSH_DELWRI_ELSE_ASYNC);

	/*
	* This loop must run at least twice. The first instance of the loop
	* will flush most meta data but that will generate more meta data
	* (typically directory updates). Which then must be flushed and
	* logged before we can write the unmount record.
	*/
	do {
	xfs_sync_attr(mp, SYNC_WAIT);
	pincount = xfs_flush_buftarg(mp->m_ddev_targp, 1);
	if (!pincount) {
	delay(50);
	count++;
	}
	} while (count < 2);
	}

	/*
	* Second stage of a quiesce. The data is already synced, now we have to take
	* care of the metadata. New transactions are already blocked, so we need to
	* wait for any remaining transactions to drain out before proceding.
	*/
	void
	xfs_quiesce_attr(
	struct xfs_mount *mp)
	{
	int error = 0;

	/* wait for all modifications to complete */
	while (atomic_read(&mp->m_active_trans) > 0)
	delay(100);

	/* flush inodes and push all remaining buffers out to disk */
	xfs_quiesce_fs(mp);

	/*
	* Just warn here till VFS can correctly support
	* read-only remount without racing.
	*/
	WARN_ON(atomic_read(&mp->m_active_trans) != 0);

	/* Push the superblock and write an unmount record */
	error = xfs_log_sbcount(mp, 1);
	if (error)
	xfs_fs_cmn_err(CE_WARN, mp,
	"xfs_attr_quiesce: failed to log sb changes. "
	"Frozen image may not be consistent.");
	xfs_log_unmount_write(mp);
	xfs_unmountfs_writesb(mp);
	}

	/*
	* Enqueue a work item to be picked up by the vfs xfssyncd thread.
	* Doing this has two advantages:
	* - It saves on stack space, which is tight in certain situations
	* - It can be used (with care) as a mechanism to avoid deadlocks.
	* Flushing while allocating in a full filesystem requires both.
	*/
	STATIC void
	xfs_syncd_queue_work(
	struct xfs_mount *mp,
	void *data,
	void (syncer)(struct xfs_mount , void *),
	struct completion *completion)
	{
	struct xfs_sync_work *work;

	work = kmem_alloc(sizeof(struct xfs_sync_work), KM_SLEEP);
	INIT_LIST_HEAD(&work->w_list);
	work->w_syncer = syncer;
	work->w_data = data;
	work->w_mount = mp;
	work->w_completion = completion;
	spin_lock(&mp->m_sync_lock);
	list_add_tail(&work->w_list, &mp->m_sync_list);
	spin_unlock(&mp->m_sync_lock);
	wake_up_process(mp->m_sync_task);
	}

	/*
	* Flush delayed allocate data, attempting to free up reserved space
	* from existing allocations. At this point a new allocation attempt
	* has failed with ENOSPC and we are in the process of scratching our
	* heads, looking about for more room...
	*/
	STATIC void
	xfs_flush_inodes_work(
	struct xfs_mount *mp,
	void *arg)
	{
	struct inode *inode = arg;
	xfs_sync_data(mp, SYNC_TRYLOCK);
	xfs_sync_data(mp, SYNC_TRYLOCK \| SYNC_WAIT);
	iput(inode);
	}

	void
	xfs_flush_inodes(
	xfs_inode_t *ip)
	{
	struct inode *inode = VFS_I(ip);
	DECLARE_COMPLETION_ONSTACK(completion);

	igrab(inode);
	xfs_syncd_queue_work(ip->i_mount, inode, xfs_flush_inodes_work, &completion);
	wait_for_completion(&completion);
	xfs_log_force(ip->i_mount, (xfs_lsn_t)0, XFS_LOG_FORCE\|XFS_LOG_SYNC);
	}

	/*
	* Every sync period we need to unpin all items, reclaim inodes, sync
	* quota and write out the superblock. We might need to cover the log
	* to indicate it is idle.
	*/
	STATIC void
	xfs_sync_worker(
	struct xfs_mount *mp,
	void *unused)
	{
	int error;

	if (!(mp->m_flags & XFS_MOUNT_RDONLY)) {
	xfs_log_force(mp, (xfs_lsn_t)0, XFS_LOG_FORCE);
	xfs_reclaim_inodes(mp, XFS_IFLUSH_DELWRI_ELSE_ASYNC);
	/* dgc: errors ignored here */
	error = xfs_qm_sync(mp, SYNC_TRYLOCK);
	error = xfs_sync_fsdata(mp, SYNC_TRYLOCK);
	}
	mp->m_sync_seq++;
	wake_up(&mp->m_wait_single_sync_task);
	}

	STATIC int
	xfssyncd(
	void *arg)
	{
	struct xfs_mount *mp = arg;
	long timeleft;
	xfs_sync_work_t work, n;
	LIST_HEAD (tmp);

	set_freezable();
	timeleft = xfs_syncd_centisecs * msecs_to_jiffies(10);
	for (;;) {
	timeleft = schedule_timeout_interruptible(timeleft);
	/* swsusp */
	try_to_freeze();
	if (kthread_should_stop() && list_empty(&mp->m_sync_list))
	break;

	spin_lock(&mp->m_sync_lock);
	/*
	* We can get woken by laptop mode, to do a sync -
	* that's the (only!) case where the list would be
	* empty with time remaining.
	*/
	if (!timeleft \|\| list_empty(&mp->m_sync_list)) {
	if (!timeleft)
	timeleft = xfs_syncd_centisecs *
	msecs_to_jiffies(10);
	INIT_LIST_HEAD(&mp->m_sync_work.w_list);
	list_add_tail(&mp->m_sync_work.w_list,
	&mp->m_sync_list);
	}
	list_for_each_entry_safe(work, n, &mp->m_sync_list, w_list)
	list_move(&work->w_list, &tmp);
	spin_unlock(&mp->m_sync_lock);

	list_for_each_entry_safe(work, n, &tmp, w_list) {
	(*work->w_syncer)(mp, work->w_data);
	list_del(&work->w_list);
	if (work == &mp->m_sync_work)
	continue;
	if (work->w_completion)
	complete(work->w_completion);
	kmem_free(work);
	}
	}

	return 0;
	}

	int
	xfs_syncd_init(
	struct xfs_mount *mp)
	{
	mp->m_sync_work.w_syncer = xfs_sync_worker;
	mp->m_sync_work.w_mount = mp;
	mp->m_sync_work.w_completion = NULL;
	mp->m_sync_task = kthread_run(xfssyncd, mp, "xfssyncd");
	if (IS_ERR(mp->m_sync_task))
	return -PTR_ERR(mp->m_sync_task);
	return 0;
	}

	void
	xfs_syncd_stop(
	struct xfs_mount *mp)
	{
	kthread_stop(mp->m_sync_task);
	}

	void
	__xfs_inode_set_reclaim_tag(
	struct xfs_perag *pag,
	struct xfs_inode *ip)
	{
	radix_tree_tag_set(&pag->pag_ici_root,
	XFS_INO_TO_AGINO(ip->i_mount, ip->i_ino),
	XFS_ICI_RECLAIM_TAG);
	}

	/*
	* We set the inode flag atomically with the radix tree tag.
	* Once we get tag lookups on the radix tree, this inode flag
	* can go away.
	*/
	void
	xfs_inode_set_reclaim_tag(
	xfs_inode_t *ip)
	{
	struct xfs_mount *mp = ip->i_mount;
	struct xfs_perag *pag;

	pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
	read_lock(&pag->pag_ici_lock);
	spin_lock(&ip->i_flags_lock);
	__xfs_inode_set_reclaim_tag(pag, ip);
	__xfs_iflags_set(ip, XFS_IRECLAIMABLE);
	spin_unlock(&ip->i_flags_lock);
	read_unlock(&pag->pag_ici_lock);
	xfs_perag_put(pag);
	}

	void
	__xfs_inode_clear_reclaim_tag(
	xfs_mount_t *mp,
	xfs_perag_t *pag,
	xfs_inode_t *ip)
	{
	radix_tree_tag_clear(&pag->pag_ici_root,
	XFS_INO_TO_AGINO(mp, ip->i_ino), XFS_ICI_RECLAIM_TAG);
	}

	STATIC int
	xfs_reclaim_inode(
	struct xfs_inode *ip,
	struct xfs_perag *pag,
	int sync_mode)
	{
	/*
	* The radix tree lock here protects a thread in xfs_iget from racing
	* with us starting reclaim on the inode. Once we have the
	* XFS_IRECLAIM flag set it will not touch us.
	*/
	spin_lock(&ip->i_flags_lock);
	ASSERT_ALWAYS(__xfs_iflags_test(ip, XFS_IRECLAIMABLE));
	if (__xfs_iflags_test(ip, XFS_IRECLAIM)) {
	/* ignore as it is already under reclaim */
	spin_unlock(&ip->i_flags_lock);
	write_unlock(&pag->pag_ici_lock);
	return 0;
	}
	__xfs_iflags_set(ip, XFS_IRECLAIM);
	spin_unlock(&ip->i_flags_lock);
	write_unlock(&pag->pag_ici_lock);

	/*
	* If the inode is still dirty, then flush it out. If the inode
	* is not in the AIL, then it will be OK to flush it delwri as
	* long as xfs_iflush() does not keep any references to the inode.
	* We leave that decision up to xfs_iflush() since it has the
	* knowledge of whether it's OK to simply do a delwri flush of
	* the inode or whether we need to wait until the inode is
	* pulled from the AIL.
	* We get the flush lock regardless, though, just to make sure
	* we don't free it while it is being flushed.
	*/
	xfs_ilock(ip, XFS_ILOCK_EXCL);
	xfs_iflock(ip);

	/*
	* In the case of a forced shutdown we rely on xfs_iflush() to
	* wait for the inode to be unpinned before returning an error.
	*/
	if (!is_bad_inode(VFS_I(ip)) && xfs_iflush(ip, sync_mode) == 0) {
	/* synchronize with xfs_iflush_done */
	xfs_iflock(ip);
	xfs_ifunlock(ip);
	}

	xfs_iunlock(ip, XFS_ILOCK_EXCL);
	xfs_ireclaim(ip);
	return 0;
	}

	int
	xfs_reclaim_inodes(
	xfs_mount_t *mp,
	int mode)
	{
	return xfs_inode_ag_iterator(mp, xfs_reclaim_inode, mode,
	XFS_ICI_RECLAIM_TAG, 1);
	}