fs/xfs/xfs_fsops.c - kernel/msm-5.4 - 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_inum.h"
 #include "xfs_log.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_inode_item.h"
 #include "xfs_btree.h"
 #include "xfs_error.h"
 #include "xfs_alloc.h"
 #include "xfs_ialloc.h"
 #include "xfs_fsops.h"
 #include "xfs_itable.h"
 #include "xfs_trans_space.h"
 #include "xfs_rtalloc.h"
 #include "xfs_rw.h"
 #include "xfs_filestream.h"
 #include "xfs_trace.h"

 /*
  * File system operations
  */

 int
 xfs_fs_geometry(
 	xfs_mount_t		*mp,
 	xfs_fsop_geom_t		*geo,
 	int			new_version)
 {
 	geo->blocksize = mp->m_sb.sb_blocksize;
 	geo->rtextsize = mp->m_sb.sb_rextsize;
 	geo->agblocks = mp->m_sb.sb_agblocks;
 	geo->agcount = mp->m_sb.sb_agcount;
 	geo->logblocks = mp->m_sb.sb_logblocks;
 	geo->sectsize = mp->m_sb.sb_sectsize;
 	geo->inodesize = mp->m_sb.sb_inodesize;
 	geo->imaxpct = mp->m_sb.sb_imax_pct;
 	geo->datablocks = mp->m_sb.sb_dblocks;
 	geo->rtblocks = mp->m_sb.sb_rblocks;
 	geo->rtextents = mp->m_sb.sb_rextents;
 	geo->logstart = mp->m_sb.sb_logstart;
 	ASSERT(sizeof(geo->uuid)==sizeof(mp->m_sb.sb_uuid));
 	memcpy(geo->uuid, &mp->m_sb.sb_uuid, sizeof(mp->m_sb.sb_uuid));
 	if (new_version >= 2) {
 		geo->sunit = mp->m_sb.sb_unit;
 		geo->swidth = mp->m_sb.sb_width;
 	}
 	if (new_version >= 3) {
 		geo->version = XFS_FSOP_GEOM_VERSION;
 		geo->flags =
 			(xfs_sb_version_hasattr(&mp->m_sb) ?
 				XFS_FSOP_GEOM_FLAGS_ATTR : 0) |
 			(xfs_sb_version_hasnlink(&mp->m_sb) ?
 				XFS_FSOP_GEOM_FLAGS_NLINK : 0) |
 			(xfs_sb_version_hasquota(&mp->m_sb) ?
 				XFS_FSOP_GEOM_FLAGS_QUOTA : 0) |
 			(xfs_sb_version_hasalign(&mp->m_sb) ?
 				XFS_FSOP_GEOM_FLAGS_IALIGN : 0) |
 			(xfs_sb_version_hasdalign(&mp->m_sb) ?
 				XFS_FSOP_GEOM_FLAGS_DALIGN : 0) |
 			(xfs_sb_version_hasshared(&mp->m_sb) ?
 				XFS_FSOP_GEOM_FLAGS_SHARED : 0) |
 			(xfs_sb_version_hasextflgbit(&mp->m_sb) ?
 				XFS_FSOP_GEOM_FLAGS_EXTFLG : 0) |
 			(xfs_sb_version_hasdirv2(&mp->m_sb) ?
 				XFS_FSOP_GEOM_FLAGS_DIRV2 : 0) |
 			(xfs_sb_version_hassector(&mp->m_sb) ?
 				XFS_FSOP_GEOM_FLAGS_SECTOR : 0) |
 			(xfs_sb_version_hasasciici(&mp->m_sb) ?
 				XFS_FSOP_GEOM_FLAGS_DIRV2CI : 0) |
 			(xfs_sb_version_haslazysbcount(&mp->m_sb) ?
 				XFS_FSOP_GEOM_FLAGS_LAZYSB : 0) |
 			(xfs_sb_version_hasattr2(&mp->m_sb) ?
 				XFS_FSOP_GEOM_FLAGS_ATTR2 : 0);
 		geo->logsectsize = xfs_sb_version_hassector(&mp->m_sb) ?
 				mp->m_sb.sb_logsectsize : BBSIZE;
 		geo->rtsectsize = mp->m_sb.sb_blocksize;
 		geo->dirblocksize = mp->m_dirblksize;
 	}
 	if (new_version >= 4) {
 		geo->flags |=
 			(xfs_sb_version_haslogv2(&mp->m_sb) ?
 				XFS_FSOP_GEOM_FLAGS_LOGV2 : 0);
 		geo->logsunit = mp->m_sb.sb_logsunit;
 	}
 	return 0;
 }

 static int
 xfs_growfs_data_private(
 	xfs_mount_t		*mp,		/* mount point for filesystem */
 	xfs_growfs_data_t	*in)		/* growfs data input struct */
 {
 	xfs_agf_t		*agf;
 	xfs_agi_t		*agi;
 	xfs_agnumber_t		agno;
 	xfs_extlen_t		agsize;
 	xfs_extlen_t		tmpsize;
 	xfs_alloc_rec_t		*arec;
 	struct xfs_btree_block	*block;
 	xfs_buf_t		*bp;
 	int			bucket;
 	int			dpct;
 	int			error;
 	xfs_agnumber_t		nagcount;
 	xfs_agnumber_t		nagimax = 0;
 	xfs_rfsblock_t		nb, nb_mod;
 	xfs_rfsblock_t		new;
 	xfs_rfsblock_t		nfree;
 	xfs_agnumber_t		oagcount;
 	int			pct;
 	xfs_trans_t		*tp;

 	nb = in->newblocks;
 	pct = in->imaxpct;
 	if (nb < mp->m_sb.sb_dblocks || pct < 0 || pct > 100)
 		return XFS_ERROR(EINVAL);
 	if ((error = xfs_sb_validate_fsb_count(&mp->m_sb, nb)))
 		return error;
 	dpct = pct - mp->m_sb.sb_imax_pct;
 	bp = xfs_buf_read_uncached(mp, mp->m_ddev_targp,
 				XFS_FSB_TO_BB(mp, nb) - XFS_FSS_TO_BB(mp, 1),
 				BBTOB(XFS_FSS_TO_BB(mp, 1)), 0);
 	if (!bp)
 		return EIO;
 	xfs_buf_relse(bp);

 	new = nb;	/* use new as a temporary here */
 	nb_mod = do_div(new, mp->m_sb.sb_agblocks);
 	nagcount = new + (nb_mod != 0);
 	if (nb_mod && nb_mod < XFS_MIN_AG_BLOCKS) {
 		nagcount--;
 		nb = (xfs_rfsblock_t)nagcount * mp->m_sb.sb_agblocks;
 		if (nb < mp->m_sb.sb_dblocks)
 			return XFS_ERROR(EINVAL);
 	}
 	new = nb - mp->m_sb.sb_dblocks;
 	oagcount = mp->m_sb.sb_agcount;

 	/* allocate the new per-ag structures */
 	if (nagcount > oagcount) {
 		error = xfs_initialize_perag(mp, nagcount, &nagimax);
 		if (error)
 			return error;
 	}

 	tp = xfs_trans_alloc(mp, XFS_TRANS_GROWFS);
 	tp->t_flags |= XFS_TRANS_RESERVE;
 	if ((error = xfs_trans_reserve(tp, XFS_GROWFS_SPACE_RES(mp),
 			XFS_GROWDATA_LOG_RES(mp), 0, 0, 0))) {
 		xfs_trans_cancel(tp, 0);
 		return error;
 	}

 	/*
 	 * Write new AG headers to disk. Non-transactional, but written
 	 * synchronously so they are completed prior to the growfs transaction
 	 * being logged.
 	 */
 	nfree = 0;
 	for (agno = nagcount - 1; agno >= oagcount; agno--, new -= agsize) {
 		/*
 		 * AG freelist header block
 		 */
 		bp = xfs_buf_get(mp->m_ddev_targp,
 				 XFS_AG_DADDR(mp, agno, XFS_AGF_DADDR(mp)),
 				 XFS_FSS_TO_BB(mp, 1), XBF_LOCK | XBF_MAPPED);
 		agf = XFS_BUF_TO_AGF(bp);
 		memset(agf, 0, mp->m_sb.sb_sectsize);
 		agf->agf_magicnum = cpu_to_be32(XFS_AGF_MAGIC);
 		agf->agf_versionnum = cpu_to_be32(XFS_AGF_VERSION);
 		agf->agf_seqno = cpu_to_be32(agno);
 		if (agno == nagcount - 1)
 			agsize =
 				nb -
 				(agno * (xfs_rfsblock_t)mp->m_sb.sb_agblocks);
 		else
 			agsize = mp->m_sb.sb_agblocks;
 		agf->agf_length = cpu_to_be32(agsize);
 		agf->agf_roots[XFS_BTNUM_BNOi] = cpu_to_be32(XFS_BNO_BLOCK(mp));
 		agf->agf_roots[XFS_BTNUM_CNTi] = cpu_to_be32(XFS_CNT_BLOCK(mp));
 		agf->agf_levels[XFS_BTNUM_BNOi] = cpu_to_be32(1);
 		agf->agf_levels[XFS_BTNUM_CNTi] = cpu_to_be32(1);
 		agf->agf_flfirst = 0;
 		agf->agf_fllast = cpu_to_be32(XFS_AGFL_SIZE(mp) - 1);
 		agf->agf_flcount = 0;
 		tmpsize = agsize - XFS_PREALLOC_BLOCKS(mp);
 		agf->agf_freeblks = cpu_to_be32(tmpsize);
 		agf->agf_longest = cpu_to_be32(tmpsize);
 		error = xfs_bwrite(mp, bp);
 		if (error) {
 			goto error0;
 		}
 		/*
 		 * AG inode header block
 		 */
 		bp = xfs_buf_get(mp->m_ddev_targp,
 				 XFS_AG_DADDR(mp, agno, XFS_AGI_DADDR(mp)),
 				 XFS_FSS_TO_BB(mp, 1), XBF_LOCK | XBF_MAPPED);
 		agi = XFS_BUF_TO_AGI(bp);
 		memset(agi, 0, mp->m_sb.sb_sectsize);
 		agi->agi_magicnum = cpu_to_be32(XFS_AGI_MAGIC);
 		agi->agi_versionnum = cpu_to_be32(XFS_AGI_VERSION);
 		agi->agi_seqno = cpu_to_be32(agno);
 		agi->agi_length = cpu_to_be32(agsize);
 		agi->agi_count = 0;
 		agi->agi_root = cpu_to_be32(XFS_IBT_BLOCK(mp));
 		agi->agi_level = cpu_to_be32(1);
 		agi->agi_freecount = 0;
 		agi->agi_newino = cpu_to_be32(NULLAGINO);
 		agi->agi_dirino = cpu_to_be32(NULLAGINO);
 		for (bucket = 0; bucket < XFS_AGI_UNLINKED_BUCKETS; bucket++)
 			agi->agi_unlinked[bucket] = cpu_to_be32(NULLAGINO);
 		error = xfs_bwrite(mp, bp);
 		if (error) {
 			goto error0;
 		}
 		/*
 		 * BNO btree root block
 		 */
 		bp = xfs_buf_get(mp->m_ddev_targp,
 				 XFS_AGB_TO_DADDR(mp, agno, XFS_BNO_BLOCK(mp)),
 				 BTOBB(mp->m_sb.sb_blocksize),
 				 XBF_LOCK | XBF_MAPPED);
 		block = XFS_BUF_TO_BLOCK(bp);
 		memset(block, 0, mp->m_sb.sb_blocksize);
 		block->bb_magic = cpu_to_be32(XFS_ABTB_MAGIC);
 		block->bb_level = 0;
 		block->bb_numrecs = cpu_to_be16(1);
 		block->bb_u.s.bb_leftsib = cpu_to_be32(NULLAGBLOCK);
 		block->bb_u.s.bb_rightsib = cpu_to_be32(NULLAGBLOCK);
 		arec = XFS_ALLOC_REC_ADDR(mp, block, 1);
 		arec->ar_startblock = cpu_to_be32(XFS_PREALLOC_BLOCKS(mp));
 		arec->ar_blockcount = cpu_to_be32(
 			agsize - be32_to_cpu(arec->ar_startblock));
 		error = xfs_bwrite(mp, bp);
 		if (error) {
 			goto error0;
 		}
 		/*
 		 * CNT btree root block
 		 */
 		bp = xfs_buf_get(mp->m_ddev_targp,
 				 XFS_AGB_TO_DADDR(mp, agno, XFS_CNT_BLOCK(mp)),
 				 BTOBB(mp->m_sb.sb_blocksize),
 				 XBF_LOCK | XBF_MAPPED);
 		block = XFS_BUF_TO_BLOCK(bp);
 		memset(block, 0, mp->m_sb.sb_blocksize);
 		block->bb_magic = cpu_to_be32(XFS_ABTC_MAGIC);
 		block->bb_level = 0;
 		block->bb_numrecs = cpu_to_be16(1);
 		block->bb_u.s.bb_leftsib = cpu_to_be32(NULLAGBLOCK);
 		block->bb_u.s.bb_rightsib = cpu_to_be32(NULLAGBLOCK);
 		arec = XFS_ALLOC_REC_ADDR(mp, block, 1);
 		arec->ar_startblock = cpu_to_be32(XFS_PREALLOC_BLOCKS(mp));
 		arec->ar_blockcount = cpu_to_be32(
 			agsize - be32_to_cpu(arec->ar_startblock));
 		nfree += be32_to_cpu(arec->ar_blockcount);
 		error = xfs_bwrite(mp, bp);
 		if (error) {
 			goto error0;
 		}
 		/*
 		 * INO btree root block
 		 */
 		bp = xfs_buf_get(mp->m_ddev_targp,
 				 XFS_AGB_TO_DADDR(mp, agno, XFS_IBT_BLOCK(mp)),
 				 BTOBB(mp->m_sb.sb_blocksize),
 				 XBF_LOCK | XBF_MAPPED);
 		block = XFS_BUF_TO_BLOCK(bp);
 		memset(block, 0, mp->m_sb.sb_blocksize);
 		block->bb_magic = cpu_to_be32(XFS_IBT_MAGIC);
 		block->bb_level = 0;
 		block->bb_numrecs = 0;
 		block->bb_u.s.bb_leftsib = cpu_to_be32(NULLAGBLOCK);
 		block->bb_u.s.bb_rightsib = cpu_to_be32(NULLAGBLOCK);
 		error = xfs_bwrite(mp, bp);
 		if (error) {
 			goto error0;
 		}
 	}
 	xfs_trans_agblocks_delta(tp, nfree);
 	/*
 	 * There are new blocks in the old last a.g.
 	 */
 	if (new) {
 		/*
 		 * Change the agi length.
 		 */
 		error = xfs_ialloc_read_agi(mp, tp, agno, &bp);
 		if (error) {
 			goto error0;
 		}
 		ASSERT(bp);
 		agi = XFS_BUF_TO_AGI(bp);
 		be32_add_cpu(&agi->agi_length, new);
 		ASSERT(nagcount == oagcount ||
 		       be32_to_cpu(agi->agi_length) == mp->m_sb.sb_agblocks);
 		xfs_ialloc_log_agi(tp, bp, XFS_AGI_LENGTH);
 		/*
 		 * Change agf length.
 		 */
 		error = xfs_alloc_read_agf(mp, tp, agno, 0, &bp);
 		if (error) {
 			goto error0;
 		}
 		ASSERT(bp);
 		agf = XFS_BUF_TO_AGF(bp);
 		be32_add_cpu(&agf->agf_length, new);
 		ASSERT(be32_to_cpu(agf->agf_length) ==
 		       be32_to_cpu(agi->agi_length));

 		xfs_alloc_log_agf(tp, bp, XFS_AGF_LENGTH);
 		/*
 		 * Free the new space.
 		 */
 		error = xfs_free_extent(tp, XFS_AGB_TO_FSB(mp, agno,
 			be32_to_cpu(agf->agf_length) - new), new);
 		if (error) {
 			goto error0;
 		}
 	}

 	/*
 	 * Update changed superblock fields transactionally. These are not
 	 * seen by the rest of the world until the transaction commit applies
 	 * them atomically to the superblock.
 	 */
 	if (nagcount > oagcount)
 		xfs_trans_mod_sb(tp, XFS_TRANS_SB_AGCOUNT, nagcount - oagcount);
 	if (nb > mp->m_sb.sb_dblocks)
 		xfs_trans_mod_sb(tp, XFS_TRANS_SB_DBLOCKS,
 				 nb - mp->m_sb.sb_dblocks);
 	if (nfree)
 		xfs_trans_mod_sb(tp, XFS_TRANS_SB_FDBLOCKS, nfree);
 	if (dpct)
 		xfs_trans_mod_sb(tp, XFS_TRANS_SB_IMAXPCT, dpct);
 	error = xfs_trans_commit(tp, 0);
 	if (error)
 		return error;

 	/* New allocation groups fully initialized, so update mount struct */
 	if (nagimax)
 		mp->m_maxagi = nagimax;
 	if (mp->m_sb.sb_imax_pct) {
 		__uint64_t icount = mp->m_sb.sb_dblocks * mp->m_sb.sb_imax_pct;
 		do_div(icount, 100);
 		mp->m_maxicount = icount << mp->m_sb.sb_inopblog;
 	} else
 		mp->m_maxicount = 0;
 	xfs_set_low_space_thresholds(mp);

 	/* update secondary superblocks. */
 	for (agno = 1; agno < nagcount; agno++) {
 		error = xfs_read_buf(mp, mp->m_ddev_targp,
 				  XFS_AGB_TO_DADDR(mp, agno, XFS_SB_BLOCK(mp)),
 				  XFS_FSS_TO_BB(mp, 1), 0, &bp);
 		if (error) {
 			xfs_fs_cmn_err(CE_WARN, mp,
 			"error %d reading secondary superblock for ag %d",
 				error, agno);
 			break;
 		}
 		xfs_sb_to_disk(XFS_BUF_TO_SBP(bp), &mp->m_sb, XFS_SB_ALL_BITS);
 		/*
 		 * If we get an error writing out the alternate superblocks,
 		 * just issue a warning and continue.  The real work is
 		 * already done and committed.
 		 */
 		if (!(error = xfs_bwrite(mp, bp))) {
 			continue;
 		} else {
 			xfs_fs_cmn_err(CE_WARN, mp,
 		"write error %d updating secondary superblock for ag %d",
 				error, agno);
 			break; /* no point in continuing */
 		}
 	}
 	return 0;

  error0:
 	xfs_trans_cancel(tp, XFS_TRANS_ABORT);
 	return error;
 }

 static int
 xfs_growfs_log_private(
 	xfs_mount_t		*mp,	/* mount point for filesystem */
 	xfs_growfs_log_t	*in)	/* growfs log input struct */
 {
 	xfs_extlen_t		nb;

 	nb = in->newblocks;
 	if (nb < XFS_MIN_LOG_BLOCKS || nb < XFS_B_TO_FSB(mp, XFS_MIN_LOG_BYTES))
 		return XFS_ERROR(EINVAL);
 	if (nb == mp->m_sb.sb_logblocks &&
 	    in->isint == (mp->m_sb.sb_logstart != 0))
 		return XFS_ERROR(EINVAL);
 	/*
 	 * Moving the log is hard, need new interfaces to sync
 	 * the log first, hold off all activity while moving it.
 	 * Can have shorter or longer log in the same space,
 	 * or transform internal to external log or vice versa.
 	 */
 	return XFS_ERROR(ENOSYS);
 }

 /*
  * protected versions of growfs function acquire and release locks on the mount
  * point - exported through ioctls: XFS_IOC_FSGROWFSDATA, XFS_IOC_FSGROWFSLOG,
  * XFS_IOC_FSGROWFSRT
  */


 int
 xfs_growfs_data(
 	xfs_mount_t		*mp,
 	xfs_growfs_data_t	*in)
 {
 	int error;

 	if (!capable(CAP_SYS_ADMIN))
 		return XFS_ERROR(EPERM);
 	if (!mutex_trylock(&mp->m_growlock))
 		return XFS_ERROR(EWOULDBLOCK);
 	error = xfs_growfs_data_private(mp, in);
 	mutex_unlock(&mp->m_growlock);
 	return error;
 }

 int
 xfs_growfs_log(
 	xfs_mount_t		*mp,
 	xfs_growfs_log_t	*in)
 {
 	int error;

 	if (!capable(CAP_SYS_ADMIN))
 		return XFS_ERROR(EPERM);
 	if (!mutex_trylock(&mp->m_growlock))
 		return XFS_ERROR(EWOULDBLOCK);
 	error = xfs_growfs_log_private(mp, in);
 	mutex_unlock(&mp->m_growlock);
 	return error;
 }

 /*
  * exported through ioctl XFS_IOC_FSCOUNTS
  */

 int
 xfs_fs_counts(
 	xfs_mount_t		*mp,
 	xfs_fsop_counts_t	*cnt)
 {
 	xfs_icsb_sync_counters(mp, XFS_ICSB_LAZY_COUNT);
 	spin_lock(&mp->m_sb_lock);
 	cnt->freedata = mp->m_sb.sb_fdblocks - XFS_ALLOC_SET_ASIDE(mp);
 	cnt->freertx = mp->m_sb.sb_frextents;
 	cnt->freeino = mp->m_sb.sb_ifree;
 	cnt->allocino = mp->m_sb.sb_icount;
 	spin_unlock(&mp->m_sb_lock);
 	return 0;
 }

 /*
  * exported through ioctl XFS_IOC_SET_RESBLKS & XFS_IOC_GET_RESBLKS
  *
  * xfs_reserve_blocks is called to set m_resblks
  * in the in-core mount table. The number of unused reserved blocks
  * is kept in m_resblks_avail.
  *
  * Reserve the requested number of blocks if available. Otherwise return
  * as many as possible to satisfy the request. The actual number
  * reserved are returned in outval
  *
  * A null inval pointer indicates that only the current reserved blocks
  * available  should  be returned no settings are changed.
  */

 int
 xfs_reserve_blocks(
 	xfs_mount_t             *mp,
 	__uint64_t              *inval,
 	xfs_fsop_resblks_t      *outval)
 {
 	__int64_t		lcounter, delta, fdblks_delta;
 	__uint64_t		request;

 	/* If inval is null, report current values and return */
 	if (inval == (__uint64_t *)NULL) {
 		if (!outval)
 			return EINVAL;
 		outval->resblks = mp->m_resblks;
 		outval->resblks_avail = mp->m_resblks_avail;
 		return 0;
 	}

 	request = *inval;

 	/*
 	 * With per-cpu counters, this becomes an interesting
 	 * problem. we needto work out if we are freeing or allocation
 	 * blocks first, then we can do the modification as necessary.
 	 *
 	 * We do this under the m_sb_lock so that if we are near
 	 * ENOSPC, we will hold out any changes while we work out
 	 * what to do. This means that the amount of free space can
 	 * change while we do this, so we need to retry if we end up
 	 * trying to reserve more space than is available.
 	 *
 	 * We also use the xfs_mod_incore_sb() interface so that we
 	 * don't have to care about whether per cpu counter are
 	 * enabled, disabled or even compiled in....
 	 */
 retry:
 	spin_lock(&mp->m_sb_lock);
 	xfs_icsb_sync_counters_locked(mp, 0);

 	/*
 	 * If our previous reservation was larger than the current value,
 	 * then move any unused blocks back to the free pool.
 	 */
 	fdblks_delta = 0;
 	if (mp->m_resblks > request) {
 		lcounter = mp->m_resblks_avail - request;
 		if (lcounter  > 0) {		/* release unused blocks */
 			fdblks_delta = lcounter;
 			mp->m_resblks_avail -= lcounter;
 		}
 		mp->m_resblks = request;
 	} else {
 		__int64_t	free;

 		free =  mp->m_sb.sb_fdblocks - XFS_ALLOC_SET_ASIDE(mp);
 		if (!free)
 			goto out; /* ENOSPC and fdblks_delta = 0 */

 		delta = request - mp->m_resblks;
 		lcounter = free - delta;
 		if (lcounter < 0) {
 			/* We can't satisfy the request, just get what we can */
 			mp->m_resblks += free;
 			mp->m_resblks_avail += free;
 			fdblks_delta = -free;
 		} else {
 			fdblks_delta = -delta;
 			mp->m_resblks = request;
 			mp->m_resblks_avail += delta;
 		}
 	}
 out:
 	if (outval) {
 		outval->resblks = mp->m_resblks;
 		outval->resblks_avail = mp->m_resblks_avail;
 	}
 	spin_unlock(&mp->m_sb_lock);

 	if (fdblks_delta) {
 		/*
 		 * If we are putting blocks back here, m_resblks_avail is
 		 * already at its max so this will put it in the free pool.
 		 *
 		 * If we need space, we'll either succeed in getting it
 		 * from the free block count or we'll get an enospc. If
 		 * we get a ENOSPC, it means things changed while we were
 		 * calculating fdblks_delta and so we should try again to
 		 * see if there is anything left to reserve.
 		 *
 		 * Don't set the reserved flag here - we don't want to reserve
 		 * the extra reserve blocks from the reserve.....
 		 */
 		int error;
 		error = xfs_icsb_modify_counters(mp, XFS_SBS_FDBLOCKS,
 						 fdblks_delta, 0);
 		if (error == ENOSPC)
 			goto retry;
 	}
 	return 0;
 }

 /*
  * Dump a transaction into the log that contains no real change. This is needed
  * to be able to make the log dirty or stamp the current tail LSN into the log
  * during the covering operation.
  *
  * We cannot use an inode here for this - that will push dirty state back up
  * into the VFS and then periodic inode flushing will prevent log covering from
  * making progress. Hence we log a field in the superblock instead and use a
  * synchronous transaction to ensure the superblock is immediately unpinned
  * and can be written back.
  */
 int
 xfs_fs_log_dummy(
 	xfs_mount_t	*mp)
 {
 	xfs_trans_t	*tp;
 	int		error;

 	tp = _xfs_trans_alloc(mp, XFS_TRANS_DUMMY1, KM_SLEEP);
 	error = xfs_trans_reserve(tp, 0, mp->m_sb.sb_sectsize + 128, 0, 0,
 					XFS_DEFAULT_LOG_COUNT);
 	if (error) {
 		xfs_trans_cancel(tp, 0);
 		return error;
 	}

 	/* log the UUID because it is an unchanging field */
 	xfs_mod_sb(tp, XFS_SB_UUID);
 	xfs_trans_set_sync(tp);
 	return xfs_trans_commit(tp, 0);
 }

 int
 xfs_fs_goingdown(
 	xfs_mount_t	*mp,
 	__uint32_t	inflags)
 {
 	switch (inflags) {
 	case XFS_FSOP_GOING_FLAGS_DEFAULT: {
 		struct super_block *sb = freeze_bdev(mp->m_super->s_bdev);

 		if (sb && !IS_ERR(sb)) {
 			xfs_force_shutdown(mp, SHUTDOWN_FORCE_UMOUNT);
 			thaw_bdev(sb->s_bdev, sb);
 		}

 		break;
 	}
 	case XFS_FSOP_GOING_FLAGS_LOGFLUSH:
 		xfs_force_shutdown(mp, SHUTDOWN_FORCE_UMOUNT);
 		break;
 	case XFS_FSOP_GOING_FLAGS_NOLOGFLUSH:
 		xfs_force_shutdown(mp,
 				SHUTDOWN_FORCE_UMOUNT | SHUTDOWN_LOG_IO_ERROR);
 		break;
 	default:
 		return XFS_ERROR(EINVAL);
 	}

 	return 0;
 }
	/*
	* 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_inum.h"
	#include "xfs_log.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_inode_item.h"
	#include "xfs_btree.h"
	#include "xfs_error.h"
	#include "xfs_alloc.h"
	#include "xfs_ialloc.h"
	#include "xfs_fsops.h"
	#include "xfs_itable.h"
	#include "xfs_trans_space.h"
	#include "xfs_rtalloc.h"
	#include "xfs_rw.h"
	#include "xfs_filestream.h"
	#include "xfs_trace.h"

	/*
	* File system operations
	*/

	int
	xfs_fs_geometry(
	xfs_mount_t *mp,
	xfs_fsop_geom_t *geo,
	int new_version)
	{
	geo->blocksize = mp->m_sb.sb_blocksize;
	geo->rtextsize = mp->m_sb.sb_rextsize;
	geo->agblocks = mp->m_sb.sb_agblocks;
	geo->agcount = mp->m_sb.sb_agcount;
	geo->logblocks = mp->m_sb.sb_logblocks;
	geo->sectsize = mp->m_sb.sb_sectsize;
	geo->inodesize = mp->m_sb.sb_inodesize;
	geo->imaxpct = mp->m_sb.sb_imax_pct;
	geo->datablocks = mp->m_sb.sb_dblocks;
	geo->rtblocks = mp->m_sb.sb_rblocks;
	geo->rtextents = mp->m_sb.sb_rextents;
	geo->logstart = mp->m_sb.sb_logstart;
	ASSERT(sizeof(geo->uuid)==sizeof(mp->m_sb.sb_uuid));
	memcpy(geo->uuid, &mp->m_sb.sb_uuid, sizeof(mp->m_sb.sb_uuid));
	if (new_version >= 2) {
	geo->sunit = mp->m_sb.sb_unit;
	geo->swidth = mp->m_sb.sb_width;
	}
	if (new_version >= 3) {
	geo->version = XFS_FSOP_GEOM_VERSION;
	geo->flags =
	(xfs_sb_version_hasattr(&mp->m_sb) ?
	XFS_FSOP_GEOM_FLAGS_ATTR : 0) \|
	(xfs_sb_version_hasnlink(&mp->m_sb) ?
	XFS_FSOP_GEOM_FLAGS_NLINK : 0) \|
	(xfs_sb_version_hasquota(&mp->m_sb) ?
	XFS_FSOP_GEOM_FLAGS_QUOTA : 0) \|
	(xfs_sb_version_hasalign(&mp->m_sb) ?
	XFS_FSOP_GEOM_FLAGS_IALIGN : 0) \|
	(xfs_sb_version_hasdalign(&mp->m_sb) ?
	XFS_FSOP_GEOM_FLAGS_DALIGN : 0) \|
	(xfs_sb_version_hasshared(&mp->m_sb) ?
	XFS_FSOP_GEOM_FLAGS_SHARED : 0) \|
	(xfs_sb_version_hasextflgbit(&mp->m_sb) ?
	XFS_FSOP_GEOM_FLAGS_EXTFLG : 0) \|
	(xfs_sb_version_hasdirv2(&mp->m_sb) ?
	XFS_FSOP_GEOM_FLAGS_DIRV2 : 0) \|
	(xfs_sb_version_hassector(&mp->m_sb) ?
	XFS_FSOP_GEOM_FLAGS_SECTOR : 0) \|
	(xfs_sb_version_hasasciici(&mp->m_sb) ?
	XFS_FSOP_GEOM_FLAGS_DIRV2CI : 0) \|
	(xfs_sb_version_haslazysbcount(&mp->m_sb) ?
	XFS_FSOP_GEOM_FLAGS_LAZYSB : 0) \|
	(xfs_sb_version_hasattr2(&mp->m_sb) ?
	XFS_FSOP_GEOM_FLAGS_ATTR2 : 0);
	geo->logsectsize = xfs_sb_version_hassector(&mp->m_sb) ?
	mp->m_sb.sb_logsectsize : BBSIZE;
	geo->rtsectsize = mp->m_sb.sb_blocksize;
	geo->dirblocksize = mp->m_dirblksize;
	}
	if (new_version >= 4) {
	geo->flags \|=
	(xfs_sb_version_haslogv2(&mp->m_sb) ?
	XFS_FSOP_GEOM_FLAGS_LOGV2 : 0);
	geo->logsunit = mp->m_sb.sb_logsunit;
	}
	return 0;
	}

	static int
	xfs_growfs_data_private(
	xfs_mount_t mp, / mount point for filesystem */
	xfs_growfs_data_t in) / growfs data input struct */
	{
	xfs_agf_t *agf;
	xfs_agi_t *agi;
	xfs_agnumber_t agno;
	xfs_extlen_t agsize;
	xfs_extlen_t tmpsize;
	xfs_alloc_rec_t *arec;
	struct xfs_btree_block *block;
	xfs_buf_t *bp;
	int bucket;
	int dpct;
	int error;
	xfs_agnumber_t nagcount;
	xfs_agnumber_t nagimax = 0;
	xfs_rfsblock_t nb, nb_mod;
	xfs_rfsblock_t new;
	xfs_rfsblock_t nfree;
	xfs_agnumber_t oagcount;
	int pct;
	xfs_trans_t *tp;

	nb = in->newblocks;
	pct = in->imaxpct;
	if (nb < mp->m_sb.sb_dblocks \|\| pct < 0 \|\| pct > 100)
	return XFS_ERROR(EINVAL);
	if ((error = xfs_sb_validate_fsb_count(&mp->m_sb, nb)))
	return error;
	dpct = pct - mp->m_sb.sb_imax_pct;
	bp = xfs_buf_read_uncached(mp, mp->m_ddev_targp,
	XFS_FSB_TO_BB(mp, nb) - XFS_FSS_TO_BB(mp, 1),
	BBTOB(XFS_FSS_TO_BB(mp, 1)), 0);
	if (!bp)
	return EIO;
	xfs_buf_relse(bp);

	new = nb; /* use new as a temporary here */
	nb_mod = do_div(new, mp->m_sb.sb_agblocks);
	nagcount = new + (nb_mod != 0);
	if (nb_mod && nb_mod < XFS_MIN_AG_BLOCKS) {
	nagcount--;
	nb = (xfs_rfsblock_t)nagcount * mp->m_sb.sb_agblocks;
	if (nb < mp->m_sb.sb_dblocks)
	return XFS_ERROR(EINVAL);
	}
	new = nb - mp->m_sb.sb_dblocks;
	oagcount = mp->m_sb.sb_agcount;

	/* allocate the new per-ag structures */
	if (nagcount > oagcount) {
	error = xfs_initialize_perag(mp, nagcount, &nagimax);
	if (error)
	return error;
	}

	tp = xfs_trans_alloc(mp, XFS_TRANS_GROWFS);
	tp->t_flags \|= XFS_TRANS_RESERVE;
	if ((error = xfs_trans_reserve(tp, XFS_GROWFS_SPACE_RES(mp),
	XFS_GROWDATA_LOG_RES(mp), 0, 0, 0))) {
	xfs_trans_cancel(tp, 0);
	return error;
	}

	/*
	* Write new AG headers to disk. Non-transactional, but written
	* synchronously so they are completed prior to the growfs transaction
	* being logged.
	*/
	nfree = 0;
	for (agno = nagcount - 1; agno >= oagcount; agno--, new -= agsize) {
	/*
	* AG freelist header block
	*/
	bp = xfs_buf_get(mp->m_ddev_targp,
	XFS_AG_DADDR(mp, agno, XFS_AGF_DADDR(mp)),
	XFS_FSS_TO_BB(mp, 1), XBF_LOCK \| XBF_MAPPED);
	agf = XFS_BUF_TO_AGF(bp);
	memset(agf, 0, mp->m_sb.sb_sectsize);
	agf->agf_magicnum = cpu_to_be32(XFS_AGF_MAGIC);
	agf->agf_versionnum = cpu_to_be32(XFS_AGF_VERSION);
	agf->agf_seqno = cpu_to_be32(agno);
	if (agno == nagcount - 1)
	agsize =
	nb -
	(agno * (xfs_rfsblock_t)mp->m_sb.sb_agblocks);
	else
	agsize = mp->m_sb.sb_agblocks;
	agf->agf_length = cpu_to_be32(agsize);
	agf->agf_roots[XFS_BTNUM_BNOi] = cpu_to_be32(XFS_BNO_BLOCK(mp));
	agf->agf_roots[XFS_BTNUM_CNTi] = cpu_to_be32(XFS_CNT_BLOCK(mp));
	agf->agf_levels[XFS_BTNUM_BNOi] = cpu_to_be32(1);
	agf->agf_levels[XFS_BTNUM_CNTi] = cpu_to_be32(1);
	agf->agf_flfirst = 0;
	agf->agf_fllast = cpu_to_be32(XFS_AGFL_SIZE(mp) - 1);
	agf->agf_flcount = 0;
	tmpsize = agsize - XFS_PREALLOC_BLOCKS(mp);
	agf->agf_freeblks = cpu_to_be32(tmpsize);
	agf->agf_longest = cpu_to_be32(tmpsize);
	error = xfs_bwrite(mp, bp);
	if (error) {
	goto error0;
	}
	/*
	* AG inode header block
	*/
	bp = xfs_buf_get(mp->m_ddev_targp,
	XFS_AG_DADDR(mp, agno, XFS_AGI_DADDR(mp)),
	XFS_FSS_TO_BB(mp, 1), XBF_LOCK \| XBF_MAPPED);
	agi = XFS_BUF_TO_AGI(bp);
	memset(agi, 0, mp->m_sb.sb_sectsize);
	agi->agi_magicnum = cpu_to_be32(XFS_AGI_MAGIC);
	agi->agi_versionnum = cpu_to_be32(XFS_AGI_VERSION);
	agi->agi_seqno = cpu_to_be32(agno);
	agi->agi_length = cpu_to_be32(agsize);
	agi->agi_count = 0;
	agi->agi_root = cpu_to_be32(XFS_IBT_BLOCK(mp));
	agi->agi_level = cpu_to_be32(1);
	agi->agi_freecount = 0;
	agi->agi_newino = cpu_to_be32(NULLAGINO);
	agi->agi_dirino = cpu_to_be32(NULLAGINO);
	for (bucket = 0; bucket < XFS_AGI_UNLINKED_BUCKETS; bucket++)
	agi->agi_unlinked[bucket] = cpu_to_be32(NULLAGINO);
	error = xfs_bwrite(mp, bp);
	if (error) {
	goto error0;
	}
	/*
	* BNO btree root block
	*/
	bp = xfs_buf_get(mp->m_ddev_targp,
	XFS_AGB_TO_DADDR(mp, agno, XFS_BNO_BLOCK(mp)),
	BTOBB(mp->m_sb.sb_blocksize),
	XBF_LOCK \| XBF_MAPPED);
	block = XFS_BUF_TO_BLOCK(bp);
	memset(block, 0, mp->m_sb.sb_blocksize);
	block->bb_magic = cpu_to_be32(XFS_ABTB_MAGIC);
	block->bb_level = 0;
	block->bb_numrecs = cpu_to_be16(1);
	block->bb_u.s.bb_leftsib = cpu_to_be32(NULLAGBLOCK);
	block->bb_u.s.bb_rightsib = cpu_to_be32(NULLAGBLOCK);
	arec = XFS_ALLOC_REC_ADDR(mp, block, 1);
	arec->ar_startblock = cpu_to_be32(XFS_PREALLOC_BLOCKS(mp));
	arec->ar_blockcount = cpu_to_be32(
	agsize - be32_to_cpu(arec->ar_startblock));
	error = xfs_bwrite(mp, bp);
	if (error) {
	goto error0;
	}
	/*
	* CNT btree root block
	*/
	bp = xfs_buf_get(mp->m_ddev_targp,
	XFS_AGB_TO_DADDR(mp, agno, XFS_CNT_BLOCK(mp)),
	BTOBB(mp->m_sb.sb_blocksize),
	XBF_LOCK \| XBF_MAPPED);
	block = XFS_BUF_TO_BLOCK(bp);
	memset(block, 0, mp->m_sb.sb_blocksize);
	block->bb_magic = cpu_to_be32(XFS_ABTC_MAGIC);
	block->bb_level = 0;
	block->bb_numrecs = cpu_to_be16(1);
	block->bb_u.s.bb_leftsib = cpu_to_be32(NULLAGBLOCK);
	block->bb_u.s.bb_rightsib = cpu_to_be32(NULLAGBLOCK);
	arec = XFS_ALLOC_REC_ADDR(mp, block, 1);
	arec->ar_startblock = cpu_to_be32(XFS_PREALLOC_BLOCKS(mp));
	arec->ar_blockcount = cpu_to_be32(
	agsize - be32_to_cpu(arec->ar_startblock));
	nfree += be32_to_cpu(arec->ar_blockcount);
	error = xfs_bwrite(mp, bp);
	if (error) {
	goto error0;
	}
	/*
	* INO btree root block
	*/
	bp = xfs_buf_get(mp->m_ddev_targp,
	XFS_AGB_TO_DADDR(mp, agno, XFS_IBT_BLOCK(mp)),
	BTOBB(mp->m_sb.sb_blocksize),
	XBF_LOCK \| XBF_MAPPED);
	block = XFS_BUF_TO_BLOCK(bp);
	memset(block, 0, mp->m_sb.sb_blocksize);
	block->bb_magic = cpu_to_be32(XFS_IBT_MAGIC);
	block->bb_level = 0;
	block->bb_numrecs = 0;
	block->bb_u.s.bb_leftsib = cpu_to_be32(NULLAGBLOCK);
	block->bb_u.s.bb_rightsib = cpu_to_be32(NULLAGBLOCK);
	error = xfs_bwrite(mp, bp);
	if (error) {
	goto error0;
	}
	}
	xfs_trans_agblocks_delta(tp, nfree);
	/*
	* There are new blocks in the old last a.g.
	*/
	if (new) {
	/*
	* Change the agi length.
	*/
	error = xfs_ialloc_read_agi(mp, tp, agno, &bp);
	if (error) {
	goto error0;
	}
	ASSERT(bp);
	agi = XFS_BUF_TO_AGI(bp);
	be32_add_cpu(&agi->agi_length, new);
	ASSERT(nagcount == oagcount \|\|
	be32_to_cpu(agi->agi_length) == mp->m_sb.sb_agblocks);
	xfs_ialloc_log_agi(tp, bp, XFS_AGI_LENGTH);
	/*
	* Change agf length.
	*/
	error = xfs_alloc_read_agf(mp, tp, agno, 0, &bp);
	if (error) {
	goto error0;
	}
	ASSERT(bp);
	agf = XFS_BUF_TO_AGF(bp);
	be32_add_cpu(&agf->agf_length, new);
	ASSERT(be32_to_cpu(agf->agf_length) ==
	be32_to_cpu(agi->agi_length));

	xfs_alloc_log_agf(tp, bp, XFS_AGF_LENGTH);
	/*
	* Free the new space.
	*/
	error = xfs_free_extent(tp, XFS_AGB_TO_FSB(mp, agno,
	be32_to_cpu(agf->agf_length) - new), new);
	if (error) {
	goto error0;
	}
	}

	/*
	* Update changed superblock fields transactionally. These are not
	* seen by the rest of the world until the transaction commit applies
	* them atomically to the superblock.
	*/
	if (nagcount > oagcount)
	xfs_trans_mod_sb(tp, XFS_TRANS_SB_AGCOUNT, nagcount - oagcount);
	if (nb > mp->m_sb.sb_dblocks)
	xfs_trans_mod_sb(tp, XFS_TRANS_SB_DBLOCKS,
	nb - mp->m_sb.sb_dblocks);
	if (nfree)
	xfs_trans_mod_sb(tp, XFS_TRANS_SB_FDBLOCKS, nfree);
	if (dpct)
	xfs_trans_mod_sb(tp, XFS_TRANS_SB_IMAXPCT, dpct);
	error = xfs_trans_commit(tp, 0);
	if (error)
	return error;

	/* New allocation groups fully initialized, so update mount struct */
	if (nagimax)
	mp->m_maxagi = nagimax;
	if (mp->m_sb.sb_imax_pct) {
	__uint64_t icount = mp->m_sb.sb_dblocks * mp->m_sb.sb_imax_pct;
	do_div(icount, 100);
	mp->m_maxicount = icount << mp->m_sb.sb_inopblog;
	} else
	mp->m_maxicount = 0;
	xfs_set_low_space_thresholds(mp);

	/* update secondary superblocks. */
	for (agno = 1; agno < nagcount; agno++) {
	error = xfs_read_buf(mp, mp->m_ddev_targp,
	XFS_AGB_TO_DADDR(mp, agno, XFS_SB_BLOCK(mp)),
	XFS_FSS_TO_BB(mp, 1), 0, &bp);
	if (error) {
	xfs_fs_cmn_err(CE_WARN, mp,
	"error %d reading secondary superblock for ag %d",
	error, agno);
	break;
	}
	xfs_sb_to_disk(XFS_BUF_TO_SBP(bp), &mp->m_sb, XFS_SB_ALL_BITS);
	/*
	* If we get an error writing out the alternate superblocks,
	* just issue a warning and continue. The real work is
	* already done and committed.
	*/
	if (!(error = xfs_bwrite(mp, bp))) {
	continue;
	} else {
	xfs_fs_cmn_err(CE_WARN, mp,
	"write error %d updating secondary superblock for ag %d",
	error, agno);
	break; /* no point in continuing */
	}
	}
	return 0;

	error0:
	xfs_trans_cancel(tp, XFS_TRANS_ABORT);
	return error;
	}

	static int
	xfs_growfs_log_private(
	xfs_mount_t mp, / mount point for filesystem */
	xfs_growfs_log_t in) / growfs log input struct */
	{
	xfs_extlen_t nb;

	nb = in->newblocks;
	if (nb < XFS_MIN_LOG_BLOCKS \|\| nb < XFS_B_TO_FSB(mp, XFS_MIN_LOG_BYTES))
	return XFS_ERROR(EINVAL);
	if (nb == mp->m_sb.sb_logblocks &&
	in->isint == (mp->m_sb.sb_logstart != 0))
	return XFS_ERROR(EINVAL);
	/*
	* Moving the log is hard, need new interfaces to sync
	* the log first, hold off all activity while moving it.
	* Can have shorter or longer log in the same space,
	* or transform internal to external log or vice versa.
	*/
	return XFS_ERROR(ENOSYS);
	}

	/*
	* protected versions of growfs function acquire and release locks on the mount
	* point - exported through ioctls: XFS_IOC_FSGROWFSDATA, XFS_IOC_FSGROWFSLOG,
	* XFS_IOC_FSGROWFSRT
	*/


	int
	xfs_growfs_data(
	xfs_mount_t *mp,
	xfs_growfs_data_t *in)
	{
	int error;

	if (!capable(CAP_SYS_ADMIN))
	return XFS_ERROR(EPERM);
	if (!mutex_trylock(&mp->m_growlock))
	return XFS_ERROR(EWOULDBLOCK);
	error = xfs_growfs_data_private(mp, in);
	mutex_unlock(&mp->m_growlock);
	return error;
	}

	int
	xfs_growfs_log(
	xfs_mount_t *mp,
	xfs_growfs_log_t *in)
	{
	int error;

	if (!capable(CAP_SYS_ADMIN))
	return XFS_ERROR(EPERM);
	if (!mutex_trylock(&mp->m_growlock))
	return XFS_ERROR(EWOULDBLOCK);
	error = xfs_growfs_log_private(mp, in);
	mutex_unlock(&mp->m_growlock);
	return error;
	}

	/*
	* exported through ioctl XFS_IOC_FSCOUNTS
	*/

	int
	xfs_fs_counts(
	xfs_mount_t *mp,
	xfs_fsop_counts_t *cnt)
	{
	xfs_icsb_sync_counters(mp, XFS_ICSB_LAZY_COUNT);
	spin_lock(&mp->m_sb_lock);
	cnt->freedata = mp->m_sb.sb_fdblocks - XFS_ALLOC_SET_ASIDE(mp);
	cnt->freertx = mp->m_sb.sb_frextents;
	cnt->freeino = mp->m_sb.sb_ifree;
	cnt->allocino = mp->m_sb.sb_icount;
	spin_unlock(&mp->m_sb_lock);
	return 0;
	}

	/*
	* exported through ioctl XFS_IOC_SET_RESBLKS & XFS_IOC_GET_RESBLKS
	*
	* xfs_reserve_blocks is called to set m_resblks
	* in the in-core mount table. The number of unused reserved blocks
	* is kept in m_resblks_avail.
	*
	* Reserve the requested number of blocks if available. Otherwise return
	* as many as possible to satisfy the request. The actual number
	* reserved are returned in outval
	*
	* A null inval pointer indicates that only the current reserved blocks
	* available should be returned no settings are changed.
	*/

	int
	xfs_reserve_blocks(
	xfs_mount_t *mp,
	__uint64_t *inval,
	xfs_fsop_resblks_t *outval)
	{
	__int64_t lcounter, delta, fdblks_delta;
	__uint64_t request;

	/* If inval is null, report current values and return */
	if (inval == (__uint64_t *)NULL) {
	if (!outval)
	return EINVAL;
	outval->resblks = mp->m_resblks;
	outval->resblks_avail = mp->m_resblks_avail;
	return 0;
	}

	request = *inval;

	/*
	* With per-cpu counters, this becomes an interesting
	* problem. we needto work out if we are freeing or allocation
	* blocks first, then we can do the modification as necessary.
	*
	* We do this under the m_sb_lock so that if we are near
	* ENOSPC, we will hold out any changes while we work out
	* what to do. This means that the amount of free space can
	* change while we do this, so we need to retry if we end up
	* trying to reserve more space than is available.
	*
	* We also use the xfs_mod_incore_sb() interface so that we
	* don't have to care about whether per cpu counter are
	* enabled, disabled or even compiled in....
	*/
	retry:
	spin_lock(&mp->m_sb_lock);
	xfs_icsb_sync_counters_locked(mp, 0);

	/*
	* If our previous reservation was larger than the current value,
	* then move any unused blocks back to the free pool.
	*/
	fdblks_delta = 0;
	if (mp->m_resblks > request) {
	lcounter = mp->m_resblks_avail - request;
	if (lcounter > 0) { /* release unused blocks */
	fdblks_delta = lcounter;
	mp->m_resblks_avail -= lcounter;
	}
	mp->m_resblks = request;
	} else {
	__int64_t free;

	free = mp->m_sb.sb_fdblocks - XFS_ALLOC_SET_ASIDE(mp);
	if (!free)
	goto out; /* ENOSPC and fdblks_delta = 0 */

	delta = request - mp->m_resblks;
	lcounter = free - delta;
	if (lcounter < 0) {
	/* We can't satisfy the request, just get what we can */
	mp->m_resblks += free;
	mp->m_resblks_avail += free;
	fdblks_delta = -free;
	} else {
	fdblks_delta = -delta;
	mp->m_resblks = request;
	mp->m_resblks_avail += delta;
	}
	}
	out:
	if (outval) {
	outval->resblks = mp->m_resblks;
	outval->resblks_avail = mp->m_resblks_avail;
	}
	spin_unlock(&mp->m_sb_lock);

	if (fdblks_delta) {
	/*
	* If we are putting blocks back here, m_resblks_avail is
	* already at its max so this will put it in the free pool.
	*
	* If we need space, we'll either succeed in getting it
	* from the free block count or we'll get an enospc. If
	* we get a ENOSPC, it means things changed while we were
	* calculating fdblks_delta and so we should try again to
	* see if there is anything left to reserve.
	*
	* Don't set the reserved flag here - we don't want to reserve
	* the extra reserve blocks from the reserve.....
	*/
	int error;
	error = xfs_icsb_modify_counters(mp, XFS_SBS_FDBLOCKS,
	fdblks_delta, 0);
	if (error == ENOSPC)
	goto retry;
	}
	return 0;
	}

	/*
	* Dump a transaction into the log that contains no real change. This is needed
	* to be able to make the log dirty or stamp the current tail LSN into the log
	* during the covering operation.
	*
	* We cannot use an inode here for this - that will push dirty state back up
	* into the VFS and then periodic inode flushing will prevent log covering from
	* making progress. Hence we log a field in the superblock instead and use a
	* synchronous transaction to ensure the superblock is immediately unpinned
	* and can be written back.
	*/
	int
	xfs_fs_log_dummy(
	xfs_mount_t *mp)
	{
	xfs_trans_t *tp;
	int error;

	tp = _xfs_trans_alloc(mp, XFS_TRANS_DUMMY1, KM_SLEEP);
	error = xfs_trans_reserve(tp, 0, mp->m_sb.sb_sectsize + 128, 0, 0,
	XFS_DEFAULT_LOG_COUNT);
	if (error) {
	xfs_trans_cancel(tp, 0);
	return error;
	}

	/* log the UUID because it is an unchanging field */
	xfs_mod_sb(tp, XFS_SB_UUID);
	xfs_trans_set_sync(tp);
	return xfs_trans_commit(tp, 0);
	}

	int
	xfs_fs_goingdown(
	xfs_mount_t *mp,
	__uint32_t inflags)
	{
	switch (inflags) {
	case XFS_FSOP_GOING_FLAGS_DEFAULT: {
	struct super_block *sb = freeze_bdev(mp->m_super->s_bdev);

	if (sb && !IS_ERR(sb)) {
	xfs_force_shutdown(mp, SHUTDOWN_FORCE_UMOUNT);
	thaw_bdev(sb->s_bdev, sb);
	}

	break;
	}
	case XFS_FSOP_GOING_FLAGS_LOGFLUSH:
	xfs_force_shutdown(mp, SHUTDOWN_FORCE_UMOUNT);
	break;
	case XFS_FSOP_GOING_FLAGS_NOLOGFLUSH:
	xfs_force_shutdown(mp,
	SHUTDOWN_FORCE_UMOUNT \| SHUTDOWN_LOG_IO_ERROR);
	break;
	default:
	return XFS_ERROR(EINVAL);
	}

	return 0;
	}