patch-2.4.25 linux-2.4.25/fs/xfs/xfs_fsops.c

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diff -urN linux-2.4.24/fs/xfs/xfs_fsops.c linux-2.4.25/fs/xfs/xfs_fsops.c
@@ -0,0 +1,628 @@
+/*
+ * Copyright (c) 2000-2002 Silicon Graphics, Inc.  All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2 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.
+ *
+ * Further, this software is distributed without any warranty that it is
+ * free of the rightful claim of any third person regarding infringement
+ * or the like.  Any license provided herein, whether implied or
+ * otherwise, applies only to this software file.  Patent licenses, if
+ * any, provided herein do not apply to combinations of this program with
+ * other software, or any other product whatsoever.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write the Free Software Foundation, Inc., 59
+ * Temple Place - Suite 330, Boston MA 02111-1307, USA.
+ *
+ * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
+ * Mountain View, CA  94043, or:
+ *
+ * http://www.sgi.com
+ *
+ * For further information regarding this notice, see:
+ *
+ * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
+ */
+
+#include "xfs.h"
+#include "xfs_macros.h"
+#include "xfs_types.h"
+#include "xfs_inum.h"
+#include "xfs_log.h"
+#include "xfs_trans.h"
+#include "xfs_sb.h"
+#include "xfs_dir.h"
+#include "xfs_dmapi.h"
+#include "xfs_mount.h"
+#include "xfs_ag.h"
+#include "xfs_alloc_btree.h"
+#include "xfs_bmap_btree.h"
+#include "xfs_ialloc_btree.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_rw.h"
+#include "xfs_refcache.h"
+#include "xfs_trans_space.h"
+#include "xfs_rtalloc.h"
+#include "xfs_dir2.h"
+#include "xfs_attr_sf.h"
+#include "xfs_dir_sf.h"
+#include "xfs_dir2_sf.h"
+#include "xfs_dinode.h"
+#include "xfs_inode.h"
+#include "xfs_inode_item.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);
+		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;
+	xfs_btree_sblock_t	*block;
+	xfs_buf_t		*bp;
+	int			bucket;
+	int			dpct;
+	int			error;
+	xfs_agnumber_t		nagcount;
+	xfs_rfsblock_t		nb, nb_mod;
+	xfs_rfsblock_t		new;
+	xfs_rfsblock_t		nfree;
+	xfs_agnumber_t		oagcount;
+	int			pct;
+	xfs_sb_t		*sbp;
+	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);
+	dpct = pct - mp->m_sb.sb_imax_pct;
+	error = xfs_read_buf(mp, mp->m_ddev_targp,
+			XFS_FSB_TO_BB(mp, nb) - XFS_FSS_TO_BB(mp, 1),
+			XFS_FSS_TO_BB(mp, 1), 0, &bp);
+	if (error)
+		return error;
+	ASSERT(bp);
+	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 = 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;
+	if (nagcount > oagcount) {
+		down_write(&mp->m_peraglock);
+		mp->m_perag = kmem_realloc(mp->m_perag,
+			sizeof(xfs_perag_t) * nagcount,
+			sizeof(xfs_perag_t) * oagcount,
+			KM_SLEEP);
+		memset(&mp->m_perag[oagcount], 0,
+			(nagcount - oagcount) * sizeof(xfs_perag_t));
+		mp->m_flags |= XFS_MOUNT_32BITINODES;
+		xfs_initialize_perag(mp, nagcount);
+		up_write(&mp->m_peraglock);
+	}
+	tp = xfs_trans_alloc(mp, XFS_TRANS_GROWFS);
+	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;
+	}
+
+	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), 0);
+		agf = XFS_BUF_TO_AGF(bp);
+		memset(agf, 0, mp->m_sb.sb_sectsize);
+		INT_SET(agf->agf_magicnum, ARCH_CONVERT, XFS_AGF_MAGIC);
+		INT_SET(agf->agf_versionnum, ARCH_CONVERT, XFS_AGF_VERSION);
+		INT_SET(agf->agf_seqno, ARCH_CONVERT, agno);
+		if (agno == nagcount - 1)
+			agsize =
+				nb -
+				(agno * (xfs_rfsblock_t)mp->m_sb.sb_agblocks);
+		else
+			agsize = mp->m_sb.sb_agblocks;
+		INT_SET(agf->agf_length, ARCH_CONVERT, agsize);
+		INT_SET(agf->agf_roots[XFS_BTNUM_BNOi], ARCH_CONVERT,
+			XFS_BNO_BLOCK(mp));
+		INT_SET(agf->agf_roots[XFS_BTNUM_CNTi], ARCH_CONVERT,
+			XFS_CNT_BLOCK(mp));
+		INT_SET(agf->agf_levels[XFS_BTNUM_BNOi], ARCH_CONVERT, 1);
+		INT_SET(agf->agf_levels[XFS_BTNUM_CNTi], ARCH_CONVERT, 1);
+		INT_ZERO(agf->agf_flfirst, ARCH_CONVERT);
+		INT_SET(agf->agf_fllast, ARCH_CONVERT, XFS_AGFL_SIZE(mp) - 1);
+		INT_ZERO(agf->agf_flcount, ARCH_CONVERT);
+		tmpsize = agsize - XFS_PREALLOC_BLOCKS(mp);
+		INT_SET(agf->agf_freeblks, ARCH_CONVERT, tmpsize);
+		INT_SET(agf->agf_longest, ARCH_CONVERT, 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), 0);
+		agi = XFS_BUF_TO_AGI(bp);
+		memset(agi, 0, mp->m_sb.sb_sectsize);
+		INT_SET(agi->agi_magicnum, ARCH_CONVERT, XFS_AGI_MAGIC);
+		INT_SET(agi->agi_versionnum, ARCH_CONVERT, XFS_AGI_VERSION);
+		INT_SET(agi->agi_seqno, ARCH_CONVERT, agno);
+		INT_SET(agi->agi_length, ARCH_CONVERT, agsize);
+		INT_ZERO(agi->agi_count, ARCH_CONVERT);
+		INT_SET(agi->agi_root, ARCH_CONVERT, XFS_IBT_BLOCK(mp));
+		INT_SET(agi->agi_level, ARCH_CONVERT, 1);
+		INT_ZERO(agi->agi_freecount, ARCH_CONVERT);
+		INT_SET(agi->agi_newino, ARCH_CONVERT, NULLAGINO);
+		INT_SET(agi->agi_dirino, ARCH_CONVERT, NULLAGINO);
+		for (bucket = 0; bucket < XFS_AGI_UNLINKED_BUCKETS; bucket++)
+			INT_SET(agi->agi_unlinked[bucket], ARCH_CONVERT,
+				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), 0);
+		block = XFS_BUF_TO_SBLOCK(bp);
+		memset(block, 0, mp->m_sb.sb_blocksize);
+		INT_SET(block->bb_magic, ARCH_CONVERT, XFS_ABTB_MAGIC);
+		INT_ZERO(block->bb_level, ARCH_CONVERT);
+		INT_SET(block->bb_numrecs, ARCH_CONVERT, 1);
+		INT_SET(block->bb_leftsib, ARCH_CONVERT, NULLAGBLOCK);
+		INT_SET(block->bb_rightsib, ARCH_CONVERT, NULLAGBLOCK);
+		arec = XFS_BTREE_REC_ADDR(mp->m_sb.sb_blocksize, xfs_alloc,
+			block, 1, mp->m_alloc_mxr[0]);
+		INT_SET(arec->ar_startblock, ARCH_CONVERT,
+			XFS_PREALLOC_BLOCKS(mp));
+		INT_SET(arec->ar_blockcount, ARCH_CONVERT,
+			agsize - INT_GET(arec->ar_startblock, ARCH_CONVERT));
+		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), 0);
+		block = XFS_BUF_TO_SBLOCK(bp);
+		memset(block, 0, mp->m_sb.sb_blocksize);
+		INT_SET(block->bb_magic, ARCH_CONVERT, XFS_ABTC_MAGIC);
+		INT_ZERO(block->bb_level, ARCH_CONVERT);
+		INT_SET(block->bb_numrecs, ARCH_CONVERT, 1);
+		INT_SET(block->bb_leftsib, ARCH_CONVERT, NULLAGBLOCK);
+		INT_SET(block->bb_rightsib, ARCH_CONVERT, NULLAGBLOCK);
+		arec = XFS_BTREE_REC_ADDR(mp->m_sb.sb_blocksize, xfs_alloc,
+			block, 1, mp->m_alloc_mxr[0]);
+		INT_SET(arec->ar_startblock, ARCH_CONVERT,
+			XFS_PREALLOC_BLOCKS(mp));
+		INT_SET(arec->ar_blockcount, ARCH_CONVERT,
+			agsize - INT_GET(arec->ar_startblock, ARCH_CONVERT));
+		nfree += INT_GET(arec->ar_blockcount, ARCH_CONVERT);
+		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), 0);
+		block = XFS_BUF_TO_SBLOCK(bp);
+		memset(block, 0, mp->m_sb.sb_blocksize);
+		INT_SET(block->bb_magic, ARCH_CONVERT, XFS_IBT_MAGIC);
+		INT_ZERO(block->bb_level, ARCH_CONVERT);
+		INT_ZERO(block->bb_numrecs, ARCH_CONVERT);
+		INT_SET(block->bb_leftsib, ARCH_CONVERT, NULLAGBLOCK);
+		INT_SET(block->bb_rightsib, ARCH_CONVERT, 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);
+		INT_MOD(agi->agi_length, ARCH_CONVERT, new);
+		ASSERT(nagcount == oagcount ||
+		       INT_GET(agi->agi_length, ARCH_CONVERT) ==
+				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);
+		INT_MOD(agf->agf_length, ARCH_CONVERT, new);
+		ASSERT(INT_GET(agf->agf_length, ARCH_CONVERT) ==
+				INT_GET(agi->agi_length, ARCH_CONVERT));
+		/*
+		 * Free the new space.
+		 */
+		error = xfs_free_extent(tp, XFS_AGB_TO_FSB(mp, agno,
+			INT_GET(agf->agf_length, ARCH_CONVERT) - new), new);
+		if (error) {
+			goto error0;
+		}
+	}
+	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, NULL);
+	if (error) {
+		return error;
+	}
+	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;
+	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;
+		}
+		sbp = XFS_BUF_TO_SBP(bp);
+		xfs_xlatesb(sbp, &mp->m_sb, -1, ARCH_CONVERT, 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 (!cpsema(&mp->m_growlock))
+		return XFS_ERROR(EWOULDBLOCK);
+	error = xfs_growfs_data_private(mp, in);
+	vsema(&mp->m_growlock);
+	return error;
+}
+
+int
+xfs_growfs_log(
+	xfs_mount_t		*mp,
+	xfs_growfs_log_t	*in)
+{
+	int error;
+	if (!cpsema(&mp->m_growlock))
+		return XFS_ERROR(EWOULDBLOCK);
+	error = xfs_growfs_log_private(mp, in);
+	vsema(&mp->m_growlock);
+	return error;
+}
+
+/*
+ * exported through ioctl XFS_IOC_FSCOUNTS
+ */
+
+int
+xfs_fs_counts(
+	xfs_mount_t		*mp,
+	xfs_fsop_counts_t	*cnt)
+{
+	unsigned long	s;
+
+	s = XFS_SB_LOCK(mp);
+	cnt->freedata = mp->m_sb.sb_fdblocks;
+	cnt->freertx = mp->m_sb.sb_frextents;
+	cnt->freeino = mp->m_sb.sb_ifree;
+	cnt->allocino = mp->m_sb.sb_icount;
+	XFS_SB_UNLOCK(mp, s);
+	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_resbls_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)
+{
+	__uint64_t              lcounter, delta;
+	__uint64_t              request;
+	unsigned long s;
+
+	/* If inval is null, report current values and return */
+
+	if (inval == (__uint64_t *)NULL) {
+		outval->resblks = mp->m_resblks;
+		outval->resblks_avail = mp->m_resblks_avail;
+		return(0);
+	}
+
+	request = *inval;
+	s = XFS_SB_LOCK(mp);
+
+	/*
+	 * If our previous reservation was larger than the current value,
+	 * then move any unused blocks back to the free pool.
+	 */
+
+	if (mp->m_resblks > request) {
+		lcounter = mp->m_resblks_avail - request;
+		if (lcounter  > 0) {		/* release unused blocks */
+			mp->m_sb.sb_fdblocks += lcounter;
+			mp->m_resblks_avail -= lcounter;
+		}
+		mp->m_resblks = request;
+	} else {
+		delta = request - mp->m_resblks;
+		lcounter = mp->m_sb.sb_fdblocks;
+		lcounter -= delta;
+		if (lcounter < 0) {
+			/* We can't satisfy the request, just get what we can */
+			mp->m_resblks += mp->m_sb.sb_fdblocks;
+			mp->m_resblks_avail += mp->m_sb.sb_fdblocks;
+			mp->m_sb.sb_fdblocks = 0;
+		} else {
+			mp->m_sb.sb_fdblocks = lcounter;
+			mp->m_resblks = request;
+			mp->m_resblks_avail += delta;
+		}
+	}
+
+	outval->resblks = mp->m_resblks;
+	outval->resblks_avail = mp->m_resblks_avail;
+	XFS_SB_UNLOCK(mp, s);
+	return(0);
+}
+
+void
+xfs_fs_log_dummy(xfs_mount_t *mp)
+{
+	xfs_trans_t *tp;
+	xfs_inode_t *ip;
+
+
+	tp = _xfs_trans_alloc(mp, XFS_TRANS_DUMMY1);
+	atomic_inc(&mp->m_active_trans);
+	if (xfs_trans_reserve(tp, 0, XFS_ICHANGE_LOG_RES(mp), 0, 0, 0)) {
+		xfs_trans_cancel(tp, 0);
+		return;
+	}
+
+	ip = mp->m_rootip;
+	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);
+	xfs_trans_commit(tp, XFS_TRANS_SYNC, NULL);
+
+	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+}
+
+int
+xfs_fs_freeze(
+	xfs_mount_t	*mp)
+{
+	vfs_t		*vfsp;
+	/*REFERENCED*/
+	int		error;
+
+	vfsp = XFS_MTOVFS(mp);
+
+	/* Stop new writers */
+	xfs_start_freeze(mp, XFS_FREEZE_WRITE);
+
+	/* Flush the refcache */
+	xfs_refcache_purge_mp(mp);
+
+	/* Flush delalloc and delwri data */
+	VFS_SYNC(vfsp, SYNC_DELWRI|SYNC_WAIT, NULL, error);
+
+	/* Pause transaction subsystem */
+	xfs_start_freeze(mp, XFS_FREEZE_TRANS);
+
+	/* Flush any remaining inodes into buffers */
+	VFS_SYNC(vfsp, SYNC_ATTR|SYNC_WAIT, NULL, error);
+
+	/* Push all buffers out to disk */
+	xfs_binval(mp->m_ddev_targp);
+	if (mp->m_rtdev_targp) {
+		xfs_binval(mp->m_rtdev_targp);
+	}
+
+	/* Push the superblock and write an unmount record */
+	xfs_log_unmount_write(mp);
+	xfs_unmountfs_writesb(mp);
+
+	return 0;
+}
+
+int
+xfs_fs_thaw(
+	xfs_mount_t	*mp)
+{
+	xfs_finish_freeze(mp);
+	return 0;
+}

FUNET's LINUX-ADM group, linux-adm@nic.funet.fi
TCL-scripts by Sam Shen (who was at: slshen@lbl.gov)