Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 3270 insertions, 0 deletions

diff --git a/fs/jfs/jfs_imap.c b/fs/jfs/jfs_imap.c
new file mode 100644
index 0000000..7838313
--- /dev/null
+++ b/fs/jfs/jfs_imap.c
@@ -0,0 +1,3270 @@
+/*
+ *   Copyright (C) International Business Machines Corp., 2000-2004
+ *
+ *   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; either version 2 of the License, or 
+ *   (at your option) any later version.
+ * 
+ *   This program is distributed in the hope that it will 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 to the Free Software 
+ *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+/*
+ *	jfs_imap.c: inode allocation map manager
+ *
+ * Serialization:
+ *   Each AG has a simple lock which is used to control the serialization of
+ *	the AG level lists.  This lock should be taken first whenever an AG
+ *	level list will be modified or accessed.
+ *
+ *   Each IAG is locked by obtaining the buffer for the IAG page.
+ *
+ *   There is also a inode lock for the inode map inode.  A read lock needs to
+ *	be taken whenever an IAG is read from the map or the global level
+ *	information is read.  A write lock needs to be taken whenever the global
+ *	level information is modified or an atomic operation needs to be used.
+ *
+ *	If more than one IAG is read at one time, the read lock may not
+ *	be given up until all of the IAG's are read.  Otherwise, a deadlock
+ *	may occur when trying to obtain the read lock while another thread
+ *	holding the read lock is waiting on the IAG already being held.
+ *
+ *   The control page of the inode map is read into memory by diMount().
+ *	Thereafter it should only be modified in memory and then it will be
+ *	written out when the filesystem is unmounted by diUnmount().
+ */
+
+#include <linux/fs.h>
+#include <linux/buffer_head.h>
+#include <linux/pagemap.h>
+#include <linux/quotaops.h>
+
+#include "jfs_incore.h"
+#include "jfs_filsys.h"
+#include "jfs_dinode.h"
+#include "jfs_dmap.h"
+#include "jfs_imap.h"
+#include "jfs_metapage.h"
+#include "jfs_superblock.h"
+#include "jfs_debug.h"
+
+/*
+ * imap locks
+ */
+/* iag free list lock */
+#define IAGFREE_LOCK_INIT(imap)		init_MUTEX(&imap->im_freelock)
+#define IAGFREE_LOCK(imap)		down(&imap->im_freelock)
+#define IAGFREE_UNLOCK(imap)		up(&imap->im_freelock)
+
+/* per ag iag list locks */
+#define AG_LOCK_INIT(imap,index)	init_MUTEX(&(imap->im_aglock[index]))
+#define AG_LOCK(imap,agno)		down(&imap->im_aglock[agno])
+#define AG_UNLOCK(imap,agno)		up(&imap->im_aglock[agno])
+
+/*
+ * external references
+ */
+extern struct address_space_operations jfs_aops;
+
+/*
+ * forward references
+ */
+static int diAllocAG(struct inomap *, int, boolean_t, struct inode *);
+static int diAllocAny(struct inomap *, int, boolean_t, struct inode *);
+static int diAllocBit(struct inomap *, struct iag *, int);
+static int diAllocExt(struct inomap *, int, struct inode *);
+static int diAllocIno(struct inomap *, int, struct inode *);
+static int diFindFree(u32, int);
+static int diNewExt(struct inomap *, struct iag *, int);
+static int diNewIAG(struct inomap *, int *, int, struct metapage **);
+static void duplicateIXtree(struct super_block *, s64, int, s64 *);
+
+static int diIAGRead(struct inomap * imap, int, struct metapage **);
+static int copy_from_dinode(struct dinode *, struct inode *);
+static void copy_to_dinode(struct dinode *, struct inode *);
+
+/*
+ *	debug code for double-checking inode map
+ */
+/* #define	_JFS_DEBUG_IMAP	1 */
+
+#ifdef	_JFS_DEBUG_IMAP
+#define DBG_DIINIT(imap)	DBGdiInit(imap)
+#define DBG_DIALLOC(imap, ino)	DBGdiAlloc(imap, ino)
+#define DBG_DIFREE(imap, ino)	DBGdiFree(imap, ino)
+
+static void *DBGdiInit(struct inomap * imap);
+static void DBGdiAlloc(struct inomap * imap, ino_t ino);
+static void DBGdiFree(struct inomap * imap, ino_t ino);
+#else
+#define DBG_DIINIT(imap)
+#define DBG_DIALLOC(imap, ino)
+#define DBG_DIFREE(imap, ino)
+#endif				/* _JFS_DEBUG_IMAP */
+
+/*
+ * NAME:        diMount()
+ *
+ * FUNCTION:    initialize the incore inode map control structures for
+ *		a fileset or aggregate init time.
+ *
+ *              the inode map's control structure (dinomap) is 
+ *              brought in from disk and placed in virtual memory.
+ *
+ * PARAMETERS:
+ *      ipimap  - pointer to inode map inode for the aggregate or fileset.
+ *
+ * RETURN VALUES:
+ *      0       - success
+ *      -ENOMEM  - insufficient free virtual memory.
+ *      -EIO  	- i/o error.
+ */
+int diMount(struct inode *ipimap)
+{
+	struct inomap *imap;
+	struct metapage *mp;
+	int index;
+	struct dinomap_disk *dinom_le;
+
+	/*
+	 * allocate/initialize the in-memory inode map control structure
+	 */
+	/* allocate the in-memory inode map control structure. */
+	imap = (struct inomap *) kmalloc(sizeof(struct inomap), GFP_KERNEL);
+	if (imap == NULL) {
+		jfs_err("diMount: kmalloc returned NULL!");
+		return -ENOMEM;
+	}
+
+	/* read the on-disk inode map control structure. */
+
+	mp = read_metapage(ipimap,
+			   IMAPBLKNO << JFS_SBI(ipimap->i_sb)->l2nbperpage,
+			   PSIZE, 0);
+	if (mp == NULL) {
+		kfree(imap);
+		return -EIO;
+	}
+
+	/* copy the on-disk version to the in-memory version. */
+	dinom_le = (struct dinomap_disk *) mp->data;
+	imap->im_freeiag = le32_to_cpu(dinom_le->in_freeiag);
+	imap->im_nextiag = le32_to_cpu(dinom_le->in_nextiag);
+	atomic_set(&imap->im_numinos, le32_to_cpu(dinom_le->in_numinos));
+	atomic_set(&imap->im_numfree, le32_to_cpu(dinom_le->in_numfree));
+	imap->im_nbperiext = le32_to_cpu(dinom_le->in_nbperiext);
+	imap->im_l2nbperiext = le32_to_cpu(dinom_le->in_l2nbperiext);
+	for (index = 0; index < MAXAG; index++) {
+		imap->im_agctl[index].inofree =
+		    le32_to_cpu(dinom_le->in_agctl[index].inofree);
+		imap->im_agctl[index].extfree =
+		    le32_to_cpu(dinom_le->in_agctl[index].extfree);
+		imap->im_agctl[index].numinos =
+		    le32_to_cpu(dinom_le->in_agctl[index].numinos);
+		imap->im_agctl[index].numfree =
+		    le32_to_cpu(dinom_le->in_agctl[index].numfree);
+	}
+
+	/* release the buffer. */
+	release_metapage(mp);
+
+	/*
+	 * allocate/initialize inode allocation map locks
+	 */
+	/* allocate and init iag free list lock */
+	IAGFREE_LOCK_INIT(imap);
+
+	/* allocate and init ag list locks */
+	for (index = 0; index < MAXAG; index++) {
+		AG_LOCK_INIT(imap, index);
+	}
+
+	/* bind the inode map inode and inode map control structure
+	 * to each other.
+	 */
+	imap->im_ipimap = ipimap;
+	JFS_IP(ipimap)->i_imap = imap;
+
+//      DBG_DIINIT(imap);
+
+	return (0);
+}
+
+
+/*
+ * NAME:        diUnmount()
+ *
+ * FUNCTION:    write to disk the incore inode map control structures for
+ *		a fileset or aggregate at unmount time.
+ *
+ * PARAMETERS:
+ *      ipimap  - pointer to inode map inode for the aggregate or fileset.
+ *
+ * RETURN VALUES:
+ *      0       - success
+ *      -ENOMEM  - insufficient free virtual memory.
+ *      -EIO  	- i/o error.
+ */
+int diUnmount(struct inode *ipimap, int mounterror)
+{
+	struct inomap *imap = JFS_IP(ipimap)->i_imap;
+
+	/*
+	 * update the on-disk inode map control structure
+	 */
+
+	if (!(mounterror || isReadOnly(ipimap)))
+		diSync(ipimap);
+
+	/*
+	 * Invalidate the page cache buffers
+	 */
+	truncate_inode_pages(ipimap->i_mapping, 0);
+
+	/*
+	 * free in-memory control structure
+	 */
+	kfree(imap);
+
+	return (0);
+}
+
+
+/*
+ *	diSync()
+ */
+int diSync(struct inode *ipimap)
+{
+	struct dinomap_disk *dinom_le;
+	struct inomap *imp = JFS_IP(ipimap)->i_imap;
+	struct metapage *mp;
+	int index;
+
+	/*
+	 * write imap global conrol page
+	 */
+	/* read the on-disk inode map control structure */
+	mp = get_metapage(ipimap,
+			  IMAPBLKNO << JFS_SBI(ipimap->i_sb)->l2nbperpage,
+			  PSIZE, 0);
+	if (mp == NULL) {
+		jfs_err("diSync: get_metapage failed!");
+		return -EIO;
+	}
+
+	/* copy the in-memory version to the on-disk version */
+	dinom_le = (struct dinomap_disk *) mp->data;
+	dinom_le->in_freeiag = cpu_to_le32(imp->im_freeiag);
+	dinom_le->in_nextiag = cpu_to_le32(imp->im_nextiag);
+	dinom_le->in_numinos = cpu_to_le32(atomic_read(&imp->im_numinos));
+	dinom_le->in_numfree = cpu_to_le32(atomic_read(&imp->im_numfree));
+	dinom_le->in_nbperiext = cpu_to_le32(imp->im_nbperiext);
+	dinom_le->in_l2nbperiext = cpu_to_le32(imp->im_l2nbperiext);
+	for (index = 0; index < MAXAG; index++) {
+		dinom_le->in_agctl[index].inofree =
+		    cpu_to_le32(imp->im_agctl[index].inofree);
+		dinom_le->in_agctl[index].extfree =
+		    cpu_to_le32(imp->im_agctl[index].extfree);
+		dinom_le->in_agctl[index].numinos =
+		    cpu_to_le32(imp->im_agctl[index].numinos);
+		dinom_le->in_agctl[index].numfree =
+		    cpu_to_le32(imp->im_agctl[index].numfree);
+	}
+
+	/* write out the control structure */
+	write_metapage(mp);
+
+	/*
+	 * write out dirty pages of imap
+	 */
+	filemap_fdatawrite(ipimap->i_mapping);
+	filemap_fdatawait(ipimap->i_mapping);
+
+	diWriteSpecial(ipimap, 0);
+
+	return (0);
+}
+
+
+/*
+ * NAME:        diRead()
+ *
+ * FUNCTION:    initialize an incore inode from disk.
+ *
+ *		on entry, the specifed incore inode should itself
+ *		specify the disk inode number corresponding to the
+ *		incore inode (i.e. i_number should be initialized).
+ *		
+ *		this routine handles incore inode initialization for
+ *		both "special" and "regular" inodes.  special inodes
+ *		are those required early in the mount process and
+ *	        require special handling since much of the file system
+ *		is not yet initialized.  these "special" inodes are
+ *		identified by a NULL inode map inode pointer and are
+ *		actually initialized by a call to diReadSpecial().
+ *		
+ *		for regular inodes, the iag describing the disk inode
+ *		is read from disk to determine the inode extent address
+ *		for the disk inode.  with the inode extent address in
+ *		hand, the page of the extent that contains the disk
+ *		inode is read and the disk inode is copied to the
+ *		incore inode.
+ *
+ * PARAMETERS:
+ *      ip  -  pointer to incore inode to be initialized from disk.
+ *
+ * RETURN VALUES:
+ *      0       - success
+ *      -EIO  	- i/o error.
+ *      -ENOMEM	- insufficient memory
+ *      
+ */
+int diRead(struct inode *ip)
+{
+	struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
+	int iagno, ino, extno, rc;
+	struct inode *ipimap;
+	struct dinode *dp;
+	struct iag *iagp;
+	struct metapage *mp;
+	s64 blkno, agstart;
+	struct inomap *imap;
+	int block_offset;
+	int inodes_left;
+	uint pageno;
+	int rel_inode;
+
+	jfs_info("diRead: ino = %ld", ip->i_ino);
+
+	ipimap = sbi->ipimap;
+	JFS_IP(ip)->ipimap = ipimap;
+
+	/* determine the iag number for this inode (number) */
+	iagno = INOTOIAG(ip->i_ino);
+
+	/* read the iag */
+	imap = JFS_IP(ipimap)->i_imap;
+	IREAD_LOCK(ipimap);
+	rc = diIAGRead(imap, iagno, &mp);
+	IREAD_UNLOCK(ipimap);
+	if (rc) {
+		jfs_err("diRead: diIAGRead returned %d", rc);
+		return (rc);
+	}
+
+	iagp = (struct iag *) mp->data;
+
+	/* determine inode extent that holds the disk inode */
+	ino = ip->i_ino & (INOSPERIAG - 1);
+	extno = ino >> L2INOSPEREXT;
+
+	if ((lengthPXD(&iagp->inoext[extno]) != imap->im_nbperiext) ||
+	    (addressPXD(&iagp->inoext[extno]) == 0)) {
+		release_metapage(mp);
+		return -ESTALE;
+	}
+
+	/* get disk block number of the page within the inode extent
+	 * that holds the disk inode.
+	 */
+	blkno = INOPBLK(&iagp->inoext[extno], ino, sbi->l2nbperpage);
+
+	/* get the ag for the iag */
+	agstart = le64_to_cpu(iagp->agstart);
+
+	release_metapage(mp);
+
+	rel_inode = (ino & (INOSPERPAGE - 1));
+	pageno = blkno >> sbi->l2nbperpage;
+
+	if ((block_offset = ((u32) blkno & (sbi->nbperpage - 1)))) {
+		/*
+		 * OS/2 didn't always align inode extents on page boundaries
+		 */
+		inodes_left =
+		     (sbi->nbperpage - block_offset) << sbi->l2niperblk;
+
+		if (rel_inode < inodes_left)
+			rel_inode += block_offset << sbi->l2niperblk;
+		else {
+			pageno += 1;
+			rel_inode -= inodes_left;
+		}
+	}
+
+	/* read the page of disk inode */
+	mp = read_metapage(ipimap, pageno << sbi->l2nbperpage, PSIZE, 1);
+	if (mp == 0) {
+		jfs_err("diRead: read_metapage failed");
+		return -EIO;
+	}
+
+	/* locate the the disk inode requested */
+	dp = (struct dinode *) mp->data;
+	dp += rel_inode;
+
+	if (ip->i_ino != le32_to_cpu(dp->di_number)) {
+		jfs_error(ip->i_sb, "diRead: i_ino != di_number");
+		rc = -EIO;
+	} else if (le32_to_cpu(dp->di_nlink) == 0)
+		rc = -ESTALE;
+	else
+		/* copy the disk inode to the in-memory inode */
+		rc = copy_from_dinode(dp, ip);
+
+	release_metapage(mp);
+
+	/* set the ag for the inode */
+	JFS_IP(ip)->agno = BLKTOAG(agstart, sbi);
+	JFS_IP(ip)->active_ag = -1;
+
+	return (rc);
+}
+
+
+/*
+ * NAME:        diReadSpecial()
+ *
+ * FUNCTION:    initialize a 'special' inode from disk.
+ *
+ *		this routines handles aggregate level inodes.  The
+ *		inode cache cannot differentiate between the
+ *		aggregate inodes and the filesystem inodes, so we
+ *		handle these here.  We don't actually use the aggregate
+ *	        inode map, since these inodes are at a fixed location
+ *		and in some cases the aggregate inode map isn't initialized
+ *		yet.
+ *
+ * PARAMETERS:
+ *      sb - filesystem superblock
+ *	inum - aggregate inode number
+ *	secondary - 1 if secondary aggregate inode table
+ *
+ * RETURN VALUES:
+ *      new inode	- success
+ *      NULL		- i/o error.
+ */
+struct inode *diReadSpecial(struct super_block *sb, ino_t inum, int secondary)
+{
+	struct jfs_sb_info *sbi = JFS_SBI(sb);
+	uint address;
+	struct dinode *dp;
+	struct inode *ip;
+	struct metapage *mp;
+
+	ip = new_inode(sb);
+	if (ip == NULL) {
+		jfs_err("diReadSpecial: new_inode returned NULL!");
+		return ip;
+	}
+
+	if (secondary) {
+		address = addressPXD(&sbi->ait2) >> sbi->l2nbperpage;
+		JFS_IP(ip)->ipimap = sbi->ipaimap2;
+	} else {
+		address = AITBL_OFF >> L2PSIZE;
+		JFS_IP(ip)->ipimap = sbi->ipaimap;
+	}
+
+	ASSERT(inum < INOSPEREXT);
+
+	ip->i_ino = inum;
+
+	address += inum >> 3;	/* 8 inodes per 4K page */
+
+	/* read the page of fixed disk inode (AIT) in raw mode */
+	mp = read_metapage(ip, address << sbi->l2nbperpage, PSIZE, 1);
+	if (mp == NULL) {
+		ip->i_nlink = 1;	/* Don't want iput() deleting it */
+		iput(ip);
+		return (NULL);
+	}
+
+	/* get the pointer to the disk inode of interest */
+	dp = (struct dinode *) (mp->data);
+	dp += inum % 8;		/* 8 inodes per 4K page */
+
+	/* copy on-disk inode to in-memory inode */
+	if ((copy_from_dinode(dp, ip)) != 0) {
+		/* handle bad return by returning NULL for ip */
+		ip->i_nlink = 1;	/* Don't want iput() deleting it */
+		iput(ip);
+		/* release the page */
+		release_metapage(mp);
+		return (NULL);
+
+	}
+
+	ip->i_mapping->a_ops = &jfs_aops;
+	mapping_set_gfp_mask(ip->i_mapping, GFP_NOFS);
+
+	/* Allocations to metadata inodes should not affect quotas */
+	ip->i_flags |= S_NOQUOTA;
+
+	if ((inum == FILESYSTEM_I) && (JFS_IP(ip)->ipimap == sbi->ipaimap)) {
+		sbi->gengen = le32_to_cpu(dp->di_gengen);
+		sbi->inostamp = le32_to_cpu(dp->di_inostamp);
+	}
+
+	/* release the page */
+	release_metapage(mp);
+
+	return (ip);
+}
+
+/*
+ * NAME:        diWriteSpecial()
+ *
+ * FUNCTION:    Write the special inode to disk
+ *
+ * PARAMETERS:
+ *      ip - special inode
+ *	secondary - 1 if secondary aggregate inode table
+ *
+ * RETURN VALUES: none
+ */
+
+void diWriteSpecial(struct inode *ip, int secondary)
+{
+	struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
+	uint address;
+	struct dinode *dp;
+	ino_t inum = ip->i_ino;
+	struct metapage *mp;
+
+	ip->i_state &= ~I_DIRTY;
+
+	if (secondary)
+		address = addressPXD(&sbi->ait2) >> sbi->l2nbperpage;
+	else
+		address = AITBL_OFF >> L2PSIZE;
+
+	ASSERT(inum < INOSPEREXT);
+
+	address += inum >> 3;	/* 8 inodes per 4K page */
+
+	/* read the page of fixed disk inode (AIT) in raw mode */
+	mp = read_metapage(ip, address << sbi->l2nbperpage, PSIZE, 1);
+	if (mp == NULL) {
+		jfs_err("diWriteSpecial: failed to read aggregate inode "
+			"extent!");
+		return;
+	}
+
+	/* get the pointer to the disk inode of interest */
+	dp = (struct dinode *) (mp->data);
+	dp += inum % 8;		/* 8 inodes per 4K page */
+
+	/* copy on-disk inode to in-memory inode */
+	copy_to_dinode(dp, ip);
+	memcpy(&dp->di_xtroot, &JFS_IP(ip)->i_xtroot, 288);
+
+	if (inum == FILESYSTEM_I)
+		dp->di_gengen = cpu_to_le32(sbi->gengen);
+
+	/* write the page */
+	write_metapage(mp);
+}
+
+/*
+ * NAME:        diFreeSpecial()
+ *
+ * FUNCTION:    Free allocated space for special inode
+ */
+void diFreeSpecial(struct inode *ip)
+{
+	if (ip == NULL) {
+		jfs_err("diFreeSpecial called with NULL ip!");
+		return;
+	}
+	filemap_fdatawrite(ip->i_mapping);
+	filemap_fdatawait(ip->i_mapping);
+	truncate_inode_pages(ip->i_mapping, 0);
+	iput(ip);
+}
+
+
+
+/*
+ * NAME:        diWrite()
+ *
+ * FUNCTION:    write the on-disk inode portion of the in-memory inode
+ *		to its corresponding on-disk inode.
+ *
+ *		on entry, the specifed incore inode should itself
+ *		specify the disk inode number corresponding to the
+ *		incore inode (i.e. i_number should be initialized).
+ *
+ *		the inode contains the inode extent address for the disk
+ *		inode.  with the inode extent address in hand, the
+ *		page of the extent that contains the disk inode is
+ *		read and the disk inode portion of the incore inode
+ *		is copied to the disk inode.
+ *		
+ * PARAMETERS:
+ *	tid -  transacation id
+ *      ip  -  pointer to incore inode to be written to the inode extent.
+ *
+ * RETURN VALUES:
+ *      0       - success
+ *      -EIO  	- i/o error.
+ */
+int diWrite(tid_t tid, struct inode *ip)
+{
+	struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
+	struct jfs_inode_info *jfs_ip = JFS_IP(ip);
+	int rc = 0;
+	s32 ino;
+	struct dinode *dp;
+	s64 blkno;
+	int block_offset;
+	int inodes_left;
+	struct metapage *mp;
+	uint pageno;
+	int rel_inode;
+	int dioffset;
+	struct inode *ipimap;
+	uint type;
+	lid_t lid;
+	struct tlock *ditlck, *tlck;
+	struct linelock *dilinelock, *ilinelock;
+	struct lv *lv;
+	int n;
+
+	ipimap = jfs_ip->ipimap;
+
+	ino = ip->i_ino & (INOSPERIAG - 1);
+
+	if (!addressPXD(&(jfs_ip->ixpxd)) ||
+	    (lengthPXD(&(jfs_ip->ixpxd)) !=
+	     JFS_IP(ipimap)->i_imap->im_nbperiext)) {
+		jfs_error(ip->i_sb, "diWrite: ixpxd invalid");
+		return -EIO;
+	}
+
+	/*
+	 * read the page of disk inode containing the specified inode:
+	 */
+	/* compute the block address of the page */
+	blkno = INOPBLK(&(jfs_ip->ixpxd), ino, sbi->l2nbperpage);
+
+	rel_inode = (ino & (INOSPERPAGE - 1));
+	pageno = blkno >> sbi->l2nbperpage;
+
+	if ((block_offset = ((u32) blkno & (sbi->nbperpage - 1)))) {
+		/*
+		 * OS/2 didn't always align inode extents on page boundaries
+		 */
+		inodes_left =
+		    (sbi->nbperpage - block_offset) << sbi->l2niperblk;
+
+		if (rel_inode < inodes_left)
+			rel_inode += block_offset << sbi->l2niperblk;
+		else {
+			pageno += 1;
+			rel_inode -= inodes_left;
+		}
+	}
+	/* read the page of disk inode */
+      retry:
+	mp = read_metapage(ipimap, pageno << sbi->l2nbperpage, PSIZE, 1);
+	if (mp == 0)
+		return -EIO;
+
+	/* get the pointer to the disk inode */
+	dp = (struct dinode *) mp->data;
+	dp += rel_inode;
+
+	dioffset = (ino & (INOSPERPAGE - 1)) << L2DISIZE;
+
+	/*
+	 * acquire transaction lock on the on-disk inode;
+	 * N.B. tlock is acquired on ipimap not ip;
+	 */
+	if ((ditlck =
+	     txLock(tid, ipimap, mp, tlckINODE | tlckENTRY)) == NULL)
+		goto retry;
+	dilinelock = (struct linelock *) & ditlck->lock;
+
+	/*
+	 * copy btree root from in-memory inode to on-disk inode
+	 *
+	 * (tlock is taken from inline B+-tree root in in-memory
+	 * inode when the B+-tree root is updated, which is pointed 
+	 * by jfs_ip->blid as well as being on tx tlock list)
+	 *
+	 * further processing of btree root is based on the copy 
+	 * in in-memory inode, where txLog() will log from, and, 
+	 * for xtree root, txUpdateMap() will update map and reset
+	 * XAD_NEW bit;
+	 */
+
+	if (S_ISDIR(ip->i_mode) && (lid = jfs_ip->xtlid)) {
+		/*
+		 * This is the special xtree inside the directory for storing
+		 * the directory table
+		 */
+		xtpage_t *p, *xp;
+		xad_t *xad;
+
+		jfs_ip->xtlid = 0;
+		tlck = lid_to_tlock(lid);
+		assert(tlck->type & tlckXTREE);
+		tlck->type |= tlckBTROOT;
+		tlck->mp = mp;
+		ilinelock = (struct linelock *) & tlck->lock;
+
+		/*
+		 * copy xtree root from inode to dinode:
+		 */
+		p = &jfs_ip->i_xtroot;
+		xp = (xtpage_t *) &dp->di_dirtable;
+		lv = ilinelock->lv;
+		for (n = 0; n < ilinelock->index; n++, lv++) {
+			memcpy(&xp->xad[lv->offset], &p->xad[lv->offset],
+			       lv->length << L2XTSLOTSIZE);
+		}
+
+		/* reset on-disk (metadata page) xtree XAD_NEW bit */
+		xad = &xp->xad[XTENTRYSTART];
+		for (n = XTENTRYSTART;
+		     n < le16_to_cpu(xp->header.nextindex); n++, xad++)
+			if (xad->flag & (XAD_NEW | XAD_EXTENDED))
+				xad->flag &= ~(XAD_NEW | XAD_EXTENDED);
+	}
+
+	if ((lid = jfs_ip->blid) == 0)
+		goto inlineData;
+	jfs_ip->blid = 0;
+
+	tlck = lid_to_tlock(lid);
+	type = tlck->type;
+	tlck->type |= tlckBTROOT;
+	tlck->mp = mp;
+	ilinelock = (struct linelock *) & tlck->lock;
+
+	/*
+	 *      regular file: 16 byte (XAD slot) granularity
+	 */
+	if (type & tlckXTREE) {
+		xtpage_t *p, *xp;
+		xad_t *xad;
+
+		/*
+		 * copy xtree root from inode to dinode:
+		 */
+		p = &jfs_ip->i_xtroot;
+		xp = &dp->di_xtroot;
+		lv = ilinelock->lv;
+		for (n = 0; n < ilinelock->index; n++, lv++) {
+			memcpy(&xp->xad[lv->offset], &p->xad[lv->offset],
+			       lv->length << L2XTSLOTSIZE);
+		}
+
+		/* reset on-disk (metadata page) xtree XAD_NEW bit */
+		xad = &xp->xad[XTENTRYSTART];
+		for (n = XTENTRYSTART;
+		     n < le16_to_cpu(xp->header.nextindex); n++, xad++)
+			if (xad->flag & (XAD_NEW | XAD_EXTENDED))
+				xad->flag &= ~(XAD_NEW | XAD_EXTENDED);
+	}
+	/*
+	 *      directory: 32 byte (directory entry slot) granularity
+	 */
+	else if (type & tlckDTREE) {
+		dtpage_t *p, *xp;
+
+		/*
+		 * copy dtree root from inode to dinode:
+		 */
+		p = (dtpage_t *) &jfs_ip->i_dtroot;
+		xp = (dtpage_t *) & dp->di_dtroot;
+		lv = ilinelock->lv;
+		for (n = 0; n < ilinelock->index; n++, lv++) {
+			memcpy(&xp->slot[lv->offset], &p->slot[lv->offset],
+			       lv->length << L2DTSLOTSIZE);
+		}
+	} else {
+		jfs_err("diWrite: UFO tlock");
+	}
+
+      inlineData:
+	/*
+	 * copy inline symlink from in-memory inode to on-disk inode
+	 */
+	if (S_ISLNK(ip->i_mode) && ip->i_size < IDATASIZE) {
+		lv = & dilinelock->lv[dilinelock->index];
+		lv->offset = (dioffset + 2 * 128) >> L2INODESLOTSIZE;
+		lv->length = 2;
+		memcpy(&dp->di_fastsymlink, jfs_ip->i_inline, IDATASIZE);
+		dilinelock->index++;
+	}
+	/*
+	 * copy inline data from in-memory inode to on-disk inode:
+	 * 128 byte slot granularity
+	 */
+	if (test_cflag(COMMIT_Inlineea, ip)) {
+		lv = & dilinelock->lv[dilinelock->index];
+		lv->offset = (dioffset + 3 * 128) >> L2INODESLOTSIZE;
+		lv->length = 1;
+		memcpy(&dp->di_inlineea, jfs_ip->i_inline_ea, INODESLOTSIZE);
+		dilinelock->index++;
+
+		clear_cflag(COMMIT_Inlineea, ip);
+	}
+
+	/*
+	 *      lock/copy inode base: 128 byte slot granularity
+	 */
+// baseDinode:
+	lv = & dilinelock->lv[dilinelock->index];
+	lv->offset = dioffset >> L2INODESLOTSIZE;
+	copy_to_dinode(dp, ip);
+	if (test_and_clear_cflag(COMMIT_Dirtable, ip)) {
+		lv->length = 2;
+		memcpy(&dp->di_dirtable, &jfs_ip->i_dirtable, 96);
+	} else
+		lv->length = 1;
+	dilinelock->index++;
+
+#ifdef _JFS_FASTDASD
+	/*
+	 * We aren't logging changes to the DASD used in directory inodes,
+	 * but we need to write them to disk.  If we don't unmount cleanly,
+	 * mount will recalculate the DASD used.
+	 */
+	if (S_ISDIR(ip->i_mode)
+	    && (ip->i_ipmnt->i_mntflag & JFS_DASD_ENABLED))
+		memcpy(&dp->di_DASD, &ip->i_DASD, sizeof(struct dasd));
+#endif				/*  _JFS_FASTDASD */
+
+	/* release the buffer holding the updated on-disk inode. 
+	 * the buffer will be later written by commit processing.
+	 */
+	write_metapage(mp);
+
+	return (rc);
+}
+
+
+/*
+ * NAME:        diFree(ip)
+ *
+ * FUNCTION:    free a specified inode from the inode working map
+ *		for a fileset or aggregate.
+ *
+ *		if the inode to be freed represents the first (only)
+ *		free inode within the iag, the iag will be placed on
+ *		the ag free inode list.
+ *	
+ *		freeing the inode will cause the inode extent to be
+ *		freed if the inode is the only allocated inode within
+ *		the extent.  in this case all the disk resource backing
+ *		up the inode extent will be freed. in addition, the iag
+ *		will be placed on the ag extent free list if the extent
+ *		is the first free extent in the iag.  if freeing the
+ *		extent also means that no free inodes will exist for
+ *		the iag, the iag will also be removed from the ag free
+ *		inode list.
+ *
+ *		the iag describing the inode will be freed if the extent
+ *		is to be freed and it is the only backed extent within
+ *		the iag.  in this case, the iag will be removed from the
+ *		ag free extent list and ag free inode list and placed on
+ *		the inode map's free iag list.
+ *
+ *		a careful update approach is used to provide consistency
+ *		in the face of updates to multiple buffers.  under this
+ *		approach, all required buffers are obtained before making
+ *		any updates and are held until all updates are complete.
+ *
+ * PARAMETERS:
+ *      ip  	- inode to be freed.
+ *
+ * RETURN VALUES:
+ *      0       - success
+ *      -EIO  	- i/o error.
+ */
+int diFree(struct inode *ip)
+{
+	int rc;
+	ino_t inum = ip->i_ino;
+	struct iag *iagp, *aiagp, *biagp, *ciagp, *diagp;
+	struct metapage *mp, *amp, *bmp, *cmp, *dmp;
+	int iagno, ino, extno, bitno, sword, agno;
+	int back, fwd;
+	u32 bitmap, mask;
+	struct inode *ipimap = JFS_SBI(ip->i_sb)->ipimap;
+	struct inomap *imap = JFS_IP(ipimap)->i_imap;
+	pxd_t freepxd;
+	tid_t tid;
+	struct inode *iplist[3];
+	struct tlock *tlck;
+	struct pxd_lock *pxdlock;
+
+	/*
+	 * This is just to suppress compiler warnings.  The same logic that
+	 * references these variables is used to initialize them.
+	 */
+	aiagp = biagp = ciagp = diagp = NULL;
+
+	/* get the iag number containing the inode.
+	 */
+	iagno = INOTOIAG(inum);
+
+	/* make sure that the iag is contained within 
+	 * the map.
+	 */
+	if (iagno >= imap->im_nextiag) {
+		dump_mem("imap", imap, 32);
+		jfs_error(ip->i_sb,
+			  "diFree: inum = %d, iagno = %d, nextiag = %d",
+			  (uint) inum, iagno, imap->im_nextiag);
+		return -EIO;
+	}
+
+	/* get the allocation group for this ino.
+	 */
+	agno = JFS_IP(ip)->agno;
+
+	/* Lock the AG specific inode map information
+	 */
+	AG_LOCK(imap, agno);
+
+	/* Obtain read lock in imap inode.  Don't release it until we have
+	 * read all of the IAG's that we are going to.
+	 */
+	IREAD_LOCK(ipimap);
+
+	/* read the iag.
+	 */
+	if ((rc = diIAGRead(imap, iagno, &mp))) {
+		IREAD_UNLOCK(ipimap);
+		AG_UNLOCK(imap, agno);
+		return (rc);
+	}
+	iagp = (struct iag *) mp->data;
+
+	/* get the inode number and extent number of the inode within
+	 * the iag and the inode number within the extent.
+	 */
+	ino = inum & (INOSPERIAG - 1);
+	extno = ino >> L2INOSPEREXT;
+	bitno = ino & (INOSPEREXT - 1);
+	mask = HIGHORDER >> bitno;
+
+	if (!(le32_to_cpu(iagp->wmap[extno]) & mask)) {
+		jfs_error(ip->i_sb,
+			  "diFree: wmap shows inode already free");
+	}
+
+	if (!addressPXD(&iagp->inoext[extno])) {
+		release_metapage(mp);
+		IREAD_UNLOCK(ipimap);
+		AG_UNLOCK(imap, agno);
+		jfs_error(ip->i_sb, "diFree: invalid inoext");
+		return -EIO;
+	}
+
+	/* compute the bitmap for the extent reflecting the freed inode.
+	 */
+	bitmap = le32_to_cpu(iagp->wmap[extno]) & ~mask;
+
+	if (imap->im_agctl[agno].numfree > imap->im_agctl[agno].numinos) {
+		release_metapage(mp);
+		IREAD_UNLOCK(ipimap);
+		AG_UNLOCK(imap, agno);
+		jfs_error(ip->i_sb, "diFree: numfree > numinos");
+		return -EIO;
+	}
+	/*
+	 *      inode extent still has some inodes or below low water mark:
+	 *      keep the inode extent;
+	 */
+	if (bitmap ||
+	    imap->im_agctl[agno].numfree < 96 ||
+	    (imap->im_agctl[agno].numfree < 288 &&
+	     (((imap->im_agctl[agno].numfree * 100) /
+	       imap->im_agctl[agno].numinos) <= 25))) {
+		/* if the iag currently has no free inodes (i.e.,
+		 * the inode being freed is the first free inode of iag),
+		 * insert the iag at head of the inode free list for the ag.
+		 */
+		if (iagp->nfreeinos == 0) {
+			/* check if there are any iags on the ag inode
+			 * free list.  if so, read the first one so that
+			 * we can link the current iag onto the list at
+			 * the head.
+			 */
+			if ((fwd = imap->im_agctl[agno].inofree) >= 0) {
+				/* read the iag that currently is the head
+				 * of the list.
+				 */
+				if ((rc = diIAGRead(imap, fwd, &amp))) {
+					IREAD_UNLOCK(ipimap);
+					AG_UNLOCK(imap, agno);
+					release_metapage(mp);
+					return (rc);
+				}
+				aiagp = (struct iag *) amp->data;
+
+				/* make current head point back to the iag.
+				 */
+				aiagp->inofreeback = cpu_to_le32(iagno);
+
+				write_metapage(amp);
+			}
+
+			/* iag points forward to current head and iag
+			 * becomes the new head of the list.
+			 */
+			iagp->inofreefwd =
+			    cpu_to_le32(imap->im_agctl[agno].inofree);
+			iagp->inofreeback = cpu_to_le32(-1);
+			imap->im_agctl[agno].inofree = iagno;
+		}
+		IREAD_UNLOCK(ipimap);
+
+		/* update the free inode summary map for the extent if
+		 * freeing the inode means the extent will now have free
+		 * inodes (i.e., the inode being freed is the first free 
+		 * inode of extent),
+		 */
+		if (iagp->wmap[extno] == cpu_to_le32(ONES)) {
+			sword = extno >> L2EXTSPERSUM;
+			bitno = extno & (EXTSPERSUM - 1);
+			iagp->inosmap[sword] &=
+			    cpu_to_le32(~(HIGHORDER >> bitno));
+		}
+
+		/* update the bitmap.
+		 */
+		iagp->wmap[extno] = cpu_to_le32(bitmap);
+		DBG_DIFREE(imap, inum);
+
+		/* update the free inode counts at the iag, ag and
+		 * map level.
+		 */
+		iagp->nfreeinos =
+		    cpu_to_le32(le32_to_cpu(iagp->nfreeinos) + 1);
+		imap->im_agctl[agno].numfree += 1;
+		atomic_inc(&imap->im_numfree);
+
+		/* release the AG inode map lock
+		 */
+		AG_UNLOCK(imap, agno);
+
+		/* write the iag */
+		write_metapage(mp);
+
+		return (0);
+	}
+
+
+	/*
+	 *      inode extent has become free and above low water mark:
+	 *      free the inode extent;
+	 */
+
+	/*
+	 *      prepare to update iag list(s) (careful update step 1)
+	 */
+	amp = bmp = cmp = dmp = NULL;
+	fwd = back = -1;
+
+	/* check if the iag currently has no free extents.  if so,
+	 * it will be placed on the head of the ag extent free list.
+	 */
+	if (iagp->nfreeexts == 0) {
+		/* check if the ag extent free list has any iags.
+		 * if so, read the iag at the head of the list now.
+		 * this (head) iag will be updated later to reflect
+		 * the addition of the current iag at the head of
+		 * the list.
+		 */
+		if ((fwd = imap->im_agctl[agno].extfree) >= 0) {
+			if ((rc = diIAGRead(imap, fwd, &amp)))
+				goto error_out;
+			aiagp = (struct iag *) amp->data;
+		}
+	} else {
+		/* iag has free extents. check if the addition of a free
+		 * extent will cause all extents to be free within this
+		 * iag.  if so, the iag will be removed from the ag extent
+		 * free list and placed on the inode map's free iag list.
+		 */
+		if (iagp->nfreeexts == cpu_to_le32(EXTSPERIAG - 1)) {
+			/* in preparation for removing the iag from the
+			 * ag extent free list, read the iags preceeding
+			 * and following the iag on the ag extent free
+			 * list.
+			 */
+			if ((fwd = le32_to_cpu(iagp->extfreefwd)) >= 0) {
+				if ((rc = diIAGRead(imap, fwd, &amp)))
+					goto error_out;
+				aiagp = (struct iag *) amp->data;
+			}
+
+			if ((back = le32_to_cpu(iagp->extfreeback)) >= 0) {
+				if ((rc = diIAGRead(imap, back, &bmp)))
+					goto error_out;
+				biagp = (struct iag *) bmp->data;
+			}
+		}
+	}
+
+	/* remove the iag from the ag inode free list if freeing
+	 * this extent cause the iag to have no free inodes.
+	 */
+	if (iagp->nfreeinos == cpu_to_le32(INOSPEREXT - 1)) {
+		int inofreeback = le32_to_cpu(iagp->inofreeback);
+		int inofreefwd = le32_to_cpu(iagp->inofreefwd);
+
+		/* in preparation for removing the iag from the
+		 * ag inode free list, read the iags preceeding
+		 * and following the iag on the ag inode free
+		 * list.  before reading these iags, we must make
+		 * sure that we already don't have them in hand
+		 * from up above, since re-reading an iag (buffer)
+		 * we are currently holding would cause a deadlock.
+		 */
+		if (inofreefwd >= 0) {
+
+			if (inofreefwd == fwd)
+				ciagp = (struct iag *) amp->data;
+			else if (inofreefwd == back)
+				ciagp = (struct iag *) bmp->data;
+			else {
+				if ((rc =
+				     diIAGRead(imap, inofreefwd, &cmp)))
+					goto error_out;
+				ciagp = (struct iag *) cmp->data;
+			}
+			assert(ciagp != NULL);
+		}
+
+		if (inofreeback >= 0) {
+			if (inofreeback == fwd)
+				diagp = (struct iag *) amp->data;
+			else if (inofreeback == back)
+				diagp = (struct iag *) bmp->data;
+			else {
+				if ((rc =
+				     diIAGRead(imap, inofreeback, &dmp)))
+					goto error_out;
+				diagp = (struct iag *) dmp->data;
+			}
+			assert(diagp != NULL);
+		}
+	}
+
+	IREAD_UNLOCK(ipimap);
+
+	/*
+	 * invalidate any page of the inode extent freed from buffer cache;
+	 */
+	freepxd = iagp->inoext[extno];
+	invalidate_pxd_metapages(ip, freepxd);
+
+	/*
+	 *      update iag list(s) (careful update step 2)
+	 */
+	/* add the iag to the ag extent free list if this is the
+	 * first free extent for the iag.
+	 */
+	if (iagp->nfreeexts == 0) {
+		if (fwd >= 0)
+			aiagp->extfreeback = cpu_to_le32(iagno);
+
+		iagp->extfreefwd =
+		    cpu_to_le32(imap->im_agctl[agno].extfree);
+		iagp->extfreeback = cpu_to_le32(-1);
+		imap->im_agctl[agno].extfree = iagno;
+	} else {
+		/* remove the iag from the ag extent list if all extents
+		 * are now free and place it on the inode map iag free list.
+		 */
+		if (iagp->nfreeexts == cpu_to_le32(EXTSPERIAG - 1)) {
+			if (fwd >= 0)
+				aiagp->extfreeback = iagp->extfreeback;
+
+			if (back >= 0)
+				biagp->extfreefwd = iagp->extfreefwd;
+			else
+				imap->im_agctl[agno].extfree =
+				    le32_to_cpu(iagp->extfreefwd);
+
+			iagp->extfreefwd = iagp->extfreeback = cpu_to_le32(-1);
+
+			IAGFREE_LOCK(imap);
+			iagp->iagfree = cpu_to_le32(imap->im_freeiag);
+			imap->im_freeiag = iagno;
+			IAGFREE_UNLOCK(imap);
+		}
+	}
+
+	/* remove the iag from the ag inode free list if freeing
+	 * this extent causes the iag to have no free inodes.
+	 */
+	if (iagp->nfreeinos == cpu_to_le32(INOSPEREXT - 1)) {
+		if ((int) le32_to_cpu(iagp->inofreefwd) >= 0)
+			ciagp->inofreeback = iagp->inofreeback;
+
+		if ((int) le32_to_cpu(iagp->inofreeback) >= 0)
+			diagp->inofreefwd = iagp->inofreefwd;
+		else
+			imap->im_agctl[agno].inofree =
+			    le32_to_cpu(iagp->inofreefwd);
+
+		iagp->inofreefwd = iagp->inofreeback = cpu_to_le32(-1);
+	}
+
+	/* update the inode extent address and working map 
+	 * to reflect the free extent.
+	 * the permanent map should have been updated already 
+	 * for the inode being freed.
+	 */
+	if (iagp->pmap[extno] != 0) {
+		jfs_error(ip->i_sb, "diFree: the pmap does not show inode free");
+	}
+	iagp->wmap[extno] = 0;
+	DBG_DIFREE(imap, inum);
+	PXDlength(&iagp->inoext[extno], 0);
+	PXDaddress(&iagp->inoext[extno], 0);
+
+	/* update the free extent and free inode summary maps
+	 * to reflect the freed extent.
+	 * the inode summary map is marked to indicate no inodes 
+	 * available for the freed extent.
+	 */
+	sword = extno >> L2EXTSPERSUM;
+	bitno = extno & (EXTSPERSUM - 1);
+	mask = HIGHORDER >> bitno;
+	iagp->inosmap[sword] |= cpu_to_le32(mask);
+	iagp->extsmap[sword] &= cpu_to_le32(~mask);
+
+	/* update the number of free inodes and number of free extents
+	 * for the iag.
+	 */
+	iagp->nfreeinos = cpu_to_le32(le32_to_cpu(iagp->nfreeinos) -
+				      (INOSPEREXT - 1));
+	iagp->nfreeexts = cpu_to_le32(le32_to_cpu(iagp->nfreeexts) + 1);
+
+	/* update the number of free inodes and backed inodes
+	 * at the ag and inode map level.
+	 */
+	imap->im_agctl[agno].numfree -= (INOSPEREXT - 1);
+	imap->im_agctl[agno].numinos -= INOSPEREXT;
+	atomic_sub(INOSPEREXT - 1, &imap->im_numfree);
+	atomic_sub(INOSPEREXT, &imap->im_numinos);
+
+	if (amp)
+		write_metapage(amp);
+	if (bmp)
+		write_metapage(bmp);
+	if (cmp)
+		write_metapage(cmp);
+	if (dmp)
+		write_metapage(dmp);
+
+	/*
+	 * start transaction to update block allocation map
+	 * for the inode extent freed;
+	 *
+	 * N.B. AG_LOCK is released and iag will be released below, and 
+	 * other thread may allocate inode from/reusing the ixad freed
+	 * BUT with new/different backing inode extent from the extent 
+	 * to be freed by the transaction;  
+	 */
+	tid = txBegin(ipimap->i_sb, COMMIT_FORCE);
+	down(&JFS_IP(ipimap)->commit_sem);
+
+	/* acquire tlock of the iag page of the freed ixad 
+	 * to force the page NOHOMEOK (even though no data is
+	 * logged from the iag page) until NOREDOPAGE|FREEXTENT log 
+	 * for the free of the extent is committed;
+	 * write FREEXTENT|NOREDOPAGE log record
+	 * N.B. linelock is overlaid as freed extent descriptor;
+	 */
+	tlck = txLock(tid, ipimap, mp, tlckINODE | tlckFREE);
+	pxdlock = (struct pxd_lock *) & tlck->lock;
+	pxdlock->flag = mlckFREEPXD;
+	pxdlock->pxd = freepxd;
+	pxdlock->index = 1;
+
+	write_metapage(mp);
+
+	iplist[0] = ipimap;
+
+	/*
+	 * logredo needs the IAG number and IAG extent index in order
+	 * to ensure that the IMap is consistent.  The least disruptive
+	 * way to pass these values through  to the transaction manager
+	 * is in the iplist array.  
+	 * 
+	 * It's not pretty, but it works.
+	 */
+	iplist[1] = (struct inode *) (size_t)iagno;
+	iplist[2] = (struct inode *) (size_t)extno;
+
+	rc = txCommit(tid, 1, &iplist[0], COMMIT_FORCE);
+
+	txEnd(tid);
+	up(&JFS_IP(ipimap)->commit_sem);
+
+	/* unlock the AG inode map information */
+	AG_UNLOCK(imap, agno);
+
+	return (0);
+
+      error_out:
+	IREAD_UNLOCK(ipimap);
+
+	if (amp)
+		release_metapage(amp);
+	if (bmp)
+		release_metapage(bmp);
+	if (cmp)
+		release_metapage(cmp);
+	if (dmp)
+		release_metapage(dmp);
+
+	AG_UNLOCK(imap, agno);
+
+	release_metapage(mp);
+
+	return (rc);
+}
+
+/*
+ * There are several places in the diAlloc* routines where we initialize
+ * the inode.
+ */
+static inline void
+diInitInode(struct inode *ip, int iagno, int ino, int extno, struct iag * iagp)
+{
+	struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
+	struct jfs_inode_info *jfs_ip = JFS_IP(ip);
+
+	ip->i_ino = (iagno << L2INOSPERIAG) + ino;
+	DBG_DIALLOC(JFS_IP(ipimap)->i_imap, ip->i_ino);
+	jfs_ip->ixpxd = iagp->inoext[extno];
+	jfs_ip->agno = BLKTOAG(le64_to_cpu(iagp->agstart), sbi);
+	jfs_ip->active_ag = -1;
+}
+
+
+/*
+ * NAME:        diAlloc(pip,dir,ip)
+ *
+ * FUNCTION:    allocate a disk inode from the inode working map 
+ *		for a fileset or aggregate.
+ *
+ * PARAMETERS:
+ *      pip  	- pointer to incore inode for the parent inode.
+ *      dir  	- TRUE if the new disk inode is for a directory.
+ *      ip  	- pointer to a new inode
+ *
+ * RETURN VALUES:
+ *      0       - success.
+ *      -ENOSPC	- insufficient disk resources.
+ *      -EIO  	- i/o error.
+ */
+int diAlloc(struct inode *pip, boolean_t dir, struct inode *ip)
+{
+	int rc, ino, iagno, addext, extno, bitno, sword;
+	int nwords, rem, i, agno;
+	u32 mask, inosmap, extsmap;
+	struct inode *ipimap;
+	struct metapage *mp;
+	ino_t inum;
+	struct iag *iagp;
+	struct inomap *imap;
+
+	/* get the pointers to the inode map inode and the
+	 * corresponding imap control structure.
+	 */
+	ipimap = JFS_SBI(pip->i_sb)->ipimap;
+	imap = JFS_IP(ipimap)->i_imap;
+	JFS_IP(ip)->ipimap = ipimap;
+	JFS_IP(ip)->fileset = FILESYSTEM_I;
+
+	/* for a directory, the allocation policy is to start 
+	 * at the ag level using the preferred ag.
+	 */
+	if (dir == TRUE) {
+		agno = dbNextAG(JFS_SBI(pip->i_sb)->ipbmap);
+		AG_LOCK(imap, agno);
+		goto tryag;
+	}
+
+	/* for files, the policy starts off by trying to allocate from
+	 * the same iag containing the parent disk inode:
+	 * try to allocate the new disk inode close to the parent disk
+	 * inode, using parent disk inode number + 1 as the allocation
+	 * hint.  (we use a left-to-right policy to attempt to avoid
+	 * moving backward on the disk.)  compute the hint within the
+	 * file system and the iag.
+	 */
+
+	/* get the ag number of this iag */
+	agno = JFS_IP(pip)->agno;
+
+	if (atomic_read(&JFS_SBI(pip->i_sb)->bmap->db_active[agno])) {
+		/*
+		 * There is an open file actively growing.  We want to
+		 * allocate new inodes from a different ag to avoid
+		 * fragmentation problems.
+		 */
+		agno = dbNextAG(JFS_SBI(pip->i_sb)->ipbmap);
+		AG_LOCK(imap, agno);
+		goto tryag;
+	}
+
+	inum = pip->i_ino + 1;
+	ino = inum & (INOSPERIAG - 1);
+
+	/* back off the the hint if it is outside of the iag */
+	if (ino == 0)
+		inum = pip->i_ino;
+
+	/* lock the AG inode map information */
+	AG_LOCK(imap, agno);
+
+	/* Get read lock on imap inode */
+	IREAD_LOCK(ipimap);
+
+	/* get the iag number and read the iag */
+	iagno = INOTOIAG(inum);
+	if ((rc = diIAGRead(imap, iagno, &mp))) {
+		IREAD_UNLOCK(ipimap);
+		AG_UNLOCK(imap, agno);
+		return (rc);
+	}
+	iagp = (struct iag *) mp->data;
+
+	/* determine if new inode extent is allowed to be added to the iag.
+	 * new inode extent can be added to the iag if the ag
+	 * has less than 32 free disk inodes and the iag has free extents.
+	 */
+	addext = (imap->im_agctl[agno].numfree < 32 && iagp->nfreeexts);
+
+	/*
+	 *      try to allocate from the IAG
+	 */
+	/* check if the inode may be allocated from the iag 
+	 * (i.e. the inode has free inodes or new extent can be added).
+	 */
+	if (iagp->nfreeinos || addext) {
+		/* determine the extent number of the hint.
+		 */
+		extno = ino >> L2INOSPEREXT;
+
+		/* check if the extent containing the hint has backed
+		 * inodes.  if so, try to allocate within this extent.
+		 */
+		if (addressPXD(&iagp->inoext[extno])) {
+			bitno = ino & (INOSPEREXT - 1);
+			if ((bitno =
+			     diFindFree(le32_to_cpu(iagp->wmap[extno]),
+					bitno))
+			    < INOSPEREXT) {
+				ino = (extno << L2INOSPEREXT) + bitno;
+
+				/* a free inode (bit) was found within this
+				 * extent, so allocate it.
+				 */
+				rc = diAllocBit(imap, iagp, ino);
+				IREAD_UNLOCK(ipimap);
+				if (rc) {
+					assert(rc == -EIO);
+				} else {
+					/* set the results of the allocation
+					 * and write the iag.
+					 */
+					diInitInode(ip, iagno, ino, extno,
+						    iagp);
+					mark_metapage_dirty(mp);
+				}
+				release_metapage(mp);
+
+				/* free the AG lock and return.
+				 */
+				AG_UNLOCK(imap, agno);
+				return (rc);
+			}
+
+			if (!addext)
+				extno =
+				    (extno ==
+				     EXTSPERIAG - 1) ? 0 : extno + 1;
+		}
+
+		/*
+		 * no free inodes within the extent containing the hint.
+		 *
+		 * try to allocate from the backed extents following
+		 * hint or, if appropriate (i.e. addext is true), allocate
+		 * an extent of free inodes at or following the extent
+		 * containing the hint.
+		 * 
+		 * the free inode and free extent summary maps are used
+		 * here, so determine the starting summary map position
+		 * and the number of words we'll have to examine.  again,
+		 * the approach is to allocate following the hint, so we
+		 * might have to initially ignore prior bits of the summary
+		 * map that represent extents prior to the extent containing
+		 * the hint and later revisit these bits.
+		 */
+		bitno = extno & (EXTSPERSUM - 1);
+		nwords = (bitno == 0) ? SMAPSZ : SMAPSZ + 1;
+		sword = extno >> L2EXTSPERSUM;
+
+		/* mask any prior bits for the starting words of the
+		 * summary map.
+		 */
+		mask = ONES << (EXTSPERSUM - bitno);
+		inosmap = le32_to_cpu(iagp->inosmap[sword]) | mask;
+		extsmap = le32_to_cpu(iagp->extsmap[sword]) | mask;
+
+		/* scan the free inode and free extent summary maps for
+		 * free resources.
+		 */
+		for (i = 0; i < nwords; i++) {
+			/* check if this word of the free inode summary
+			 * map describes an extent with free inodes.
+			 */
+			if (~inosmap) {
+				/* an extent with free inodes has been
+				 * found. determine the extent number
+				 * and the inode number within the extent.
+				 */
+				rem = diFindFree(inosmap, 0);
+				extno = (sword << L2EXTSPERSUM) + rem;
+				rem = diFindFree(le32_to_cpu(iagp->wmap[extno]),
+						 0);
+				if (rem >= INOSPEREXT) {
+					IREAD_UNLOCK(ipimap);
+					release_metapage(mp);
+					AG_UNLOCK(imap, agno);
+					jfs_error(ip->i_sb,
+						  "diAlloc: can't find free bit "
+						  "in wmap");
+					return EIO;
+				}
+
+				/* determine the inode number within the
+				 * iag and allocate the inode from the
+				 * map.
+				 */
+				ino = (extno << L2INOSPEREXT) + rem;
+				rc = diAllocBit(imap, iagp, ino);
+				IREAD_UNLOCK(ipimap);
+				if (rc)
+					assert(rc == -EIO);
+				else {
+					/* set the results of the allocation
+					 * and write the iag.
+					 */
+					diInitInode(ip, iagno, ino, extno,
+						    iagp);
+					mark_metapage_dirty(mp);
+				}
+				release_metapage(mp);
+
+				/* free the AG lock and return.
+				 */
+				AG_UNLOCK(imap, agno);
+				return (rc);
+
+			}
+
+			/* check if we may allocate an extent of free
+			 * inodes and whether this word of the free
+			 * extents summary map describes a free extent.
+			 */
+			if (addext && ~extsmap) {
+				/* a free extent has been found.  determine
+				 * the extent number.
+				 */
+				rem = diFindFree(extsmap, 0);
+				extno = (sword << L2EXTSPERSUM) + rem;
+
+				/* allocate an extent of free inodes.
+				 */
+				if ((rc = diNewExt(imap, iagp, extno))) {
+					/* if there is no disk space for a
+					 * new extent, try to allocate the
+					 * disk inode from somewhere else.
+					 */
+					if (rc == -ENOSPC)
+						break;
+
+					assert(rc == -EIO);
+				} else {
+					/* set the results of the allocation
+					 * and write the iag.
+					 */
+					diInitInode(ip, iagno,
+						    extno << L2INOSPEREXT,
+						    extno, iagp);
+					mark_metapage_dirty(mp);
+				}
+				release_metapage(mp);
+				/* free the imap inode & the AG lock & return.
+				 */
+				IREAD_UNLOCK(ipimap);
+				AG_UNLOCK(imap, agno);
+				return (rc);
+			}
+
+			/* move on to the next set of summary map words.
+			 */
+			sword = (sword == SMAPSZ - 1) ? 0 : sword + 1;
+			inosmap = le32_to_cpu(iagp->inosmap[sword]);
+			extsmap = le32_to_cpu(iagp->extsmap[sword]);
+		}
+	}
+	/* unlock imap inode */
+	IREAD_UNLOCK(ipimap);
+
+	/* nothing doing in this iag, so release it. */
+	release_metapage(mp);
+
+      tryag:
+	/*
+	 * try to allocate anywhere within the same AG as the parent inode.
+	 */
+	rc = diAllocAG(imap, agno, dir, ip);
+
+	AG_UNLOCK(imap, agno);
+
+	if (rc != -ENOSPC)
+		return (rc);
+
+	/*
+	 * try to allocate in any AG.
+	 */
+	return (diAllocAny(imap, agno, dir, ip));
+}
+
+
+/*
+ * NAME:        diAllocAG(imap,agno,dir,ip)
+ *
+ * FUNCTION:    allocate a disk inode from the allocation group.
+ *
+ *		this routine first determines if a new extent of free
+ *		inodes should be added for the allocation group, with
+ *		the current request satisfied from this extent. if this
+ *		is the case, an attempt will be made to do just that.  if
+ *		this attempt fails or it has been determined that a new 
+ *		extent should not be added, an attempt is made to satisfy
+ *		the request by allocating an existing (backed) free inode
+ *		from the allocation group.
+ *
+ * PRE CONDITION: Already have the AG lock for this AG.
+ *
+ * PARAMETERS:
+ *      imap  	- pointer to inode map control structure.
+ *      agno  	- allocation group to allocate from.
+ *      dir  	- TRUE if the new disk inode is for a directory.
+ *      ip  	- pointer to the new inode to be filled in on successful return
+ *		  with the disk inode number allocated, its extent address
+ *		  and the start of the ag.
+ *
+ * RETURN VALUES:
+ *      0       - success.
+ *      -ENOSPC	- insufficient disk resources.
+ *      -EIO  	- i/o error.
+ */
+static int
+diAllocAG(struct inomap * imap, int agno, boolean_t dir, struct inode *ip)
+{
+	int rc, addext, numfree, numinos;
+
+	/* get the number of free and the number of backed disk 
+	 * inodes currently within the ag.
+	 */
+	numfree = imap->im_agctl[agno].numfree;
+	numinos = imap->im_agctl[agno].numinos;
+
+	if (numfree > numinos) {
+		jfs_error(ip->i_sb, "diAllocAG: numfree > numinos");
+		return -EIO;
+	}
+
+	/* determine if we should allocate a new extent of free inodes
+	 * within the ag: for directory inodes, add a new extent
+	 * if there are a small number of free inodes or number of free
+	 * inodes is a small percentage of the number of backed inodes.
+	 */
+	if (dir == TRUE)
+		addext = (numfree < 64 ||
+			  (numfree < 256
+			   && ((numfree * 100) / numinos) <= 20));
+	else
+		addext = (numfree == 0);
+
+	/*
+	 * try to allocate a new extent of free inodes.
+	 */
+	if (addext) {
+		/* if free space is not avaliable for this new extent, try
+		 * below to allocate a free and existing (already backed)
+		 * inode from the ag.
+		 */
+		if ((rc = diAllocExt(imap, agno, ip)) != -ENOSPC)
+			return (rc);
+	}
+
+	/*
+	 * try to allocate an existing free inode from the ag.
+	 */
+	return (diAllocIno(imap, agno, ip));
+}
+
+
+/*
+ * NAME:        diAllocAny(imap,agno,dir,iap)
+ *
+ * FUNCTION:    allocate a disk inode from any other allocation group.
+ *
+ *		this routine is called when an allocation attempt within
+ *		the primary allocation group has failed. if attempts to
+ *		allocate an inode from any allocation group other than the
+ *		specified primary group.
+ *
+ * PARAMETERS:
+ *      imap  	- pointer to inode map control structure.
+ *      agno  	- primary allocation group (to avoid).
+ *      dir  	- TRUE if the new disk inode is for a directory.
+ *      ip  	- pointer to a new inode to be filled in on successful return
+ *		  with the disk inode number allocated, its extent address
+ *		  and the start of the ag.
+ *
+ * RETURN VALUES:
+ *      0       - success.
+ *      -ENOSPC	- insufficient disk resources.
+ *      -EIO  	- i/o error.
+ */
+static int
+diAllocAny(struct inomap * imap, int agno, boolean_t dir, struct inode *ip)
+{
+	int ag, rc;
+	int maxag = JFS_SBI(imap->im_ipimap->i_sb)->bmap->db_maxag;
+
+
+	/* try to allocate from the ags following agno up to 
+	 * the maximum ag number.
+	 */
+	for (ag = agno + 1; ag <= maxag; ag++) {
+		AG_LOCK(imap, ag);
+
+		rc = diAllocAG(imap, ag, dir, ip);
+
+		AG_UNLOCK(imap, ag);
+
+		if (rc != -ENOSPC)
+			return (rc);
+	}
+
+	/* try to allocate from the ags in front of agno.
+	 */
+	for (ag = 0; ag < agno; ag++) {
+		AG_LOCK(imap, ag);
+
+		rc = diAllocAG(imap, ag, dir, ip);
+
+		AG_UNLOCK(imap, ag);
+
+		if (rc != -ENOSPC)
+			return (rc);
+	}
+
+	/* no free disk inodes.
+	 */
+	return -ENOSPC;
+}
+
+
+/*
+ * NAME:        diAllocIno(imap,agno,ip)
+ *
+ * FUNCTION:    allocate a disk inode from the allocation group's free
+ *		inode list, returning an error if this free list is
+ *		empty (i.e. no iags on the list).
+ *
+ *		allocation occurs from the first iag on the list using
+ *		the iag's free inode summary map to find the leftmost
+ *		free inode in the iag. 
+ *		
+ * PRE CONDITION: Already have AG lock for this AG.
+ *		
+ * PARAMETERS:
+ *      imap  	- pointer to inode map control structure.
+ *      agno  	- allocation group.
+ *      ip  	- pointer to new inode to be filled in on successful return
+ *		  with the disk inode number allocated, its extent address
+ *		  and the start of the ag.
+ *
+ * RETURN VALUES:
+ *      0       - success.
+ *      -ENOSPC	- insufficient disk resources.
+ *      -EIO  	- i/o error.
+ */
+static int diAllocIno(struct inomap * imap, int agno, struct inode *ip)
+{
+	int iagno, ino, rc, rem, extno, sword;
+	struct metapage *mp;
+	struct iag *iagp;
+
+	/* check if there are iags on the ag's free inode list.
+	 */
+	if ((iagno = imap->im_agctl[agno].inofree) < 0)
+		return -ENOSPC;
+
+	/* obtain read lock on imap inode */
+	IREAD_LOCK(imap->im_ipimap);
+
+	/* read the iag at the head of the list.
+	 */
+	if ((rc = diIAGRead(imap, iagno, &mp))) {
+		IREAD_UNLOCK(imap->im_ipimap);
+		return (rc);
+	}
+	iagp = (struct iag *) mp->data;
+
+	/* better be free inodes in this iag if it is on the
+	 * list.
+	 */
+	if (!iagp->nfreeinos) {
+		IREAD_UNLOCK(imap->im_ipimap);
+		release_metapage(mp);
+		jfs_error(ip->i_sb,
+			  "diAllocIno: nfreeinos = 0, but iag on freelist");
+		return -EIO;
+	}
+
+	/* scan the free inode summary map to find an extent
+	 * with free inodes.
+	 */
+	for (sword = 0;; sword++) {
+		if (sword >= SMAPSZ) {
+			IREAD_UNLOCK(imap->im_ipimap);
+			release_metapage(mp);
+			jfs_error(ip->i_sb,
+				  "diAllocIno: free inode not found in summary map");
+			return -EIO;
+		}
+
+		if (~iagp->inosmap[sword])
+			break;
+	}
+
+	/* found a extent with free inodes. determine
+	 * the extent number.
+	 */
+	rem = diFindFree(le32_to_cpu(iagp->inosmap[sword]), 0);
+	if (rem >= EXTSPERSUM) {
+		IREAD_UNLOCK(imap->im_ipimap);
+		release_metapage(mp);
+		jfs_error(ip->i_sb, "diAllocIno: no free extent found");
+		return -EIO;
+	}
+	extno = (sword << L2EXTSPERSUM) + rem;
+
+	/* find the first free inode in the extent.
+	 */
+	rem = diFindFree(le32_to_cpu(iagp->wmap[extno]), 0);
+	if (rem >= INOSPEREXT) {
+		IREAD_UNLOCK(imap->im_ipimap);
+		release_metapage(mp);
+		jfs_error(ip->i_sb, "diAllocIno: free inode not found");
+		return -EIO;
+	}
+
+	/* compute the inode number within the iag. 
+	 */
+	ino = (extno << L2INOSPEREXT) + rem;
+
+	/* allocate the inode.
+	 */
+	rc = diAllocBit(imap, iagp, ino);
+	IREAD_UNLOCK(imap->im_ipimap);
+	if (rc) {
+		release_metapage(mp);
+		return (rc);
+	}
+
+	/* set the results of the allocation and write the iag.
+	 */
+	diInitInode(ip, iagno, ino, extno, iagp);
+	write_metapage(mp);
+
+	return (0);
+}
+
+
+/*
+ * NAME:        diAllocExt(imap,agno,ip)
+ *
+ * FUNCTION:   	add a new extent of free inodes to an iag, allocating
+ *	       	an inode from this extent to satisfy the current allocation
+ *	       	request.
+ *		
+ *		this routine first tries to find an existing iag with free
+ *		extents through the ag free extent list.  if list is not
+ *		empty, the head of the list will be selected as the home
+ *		of the new extent of free inodes.  otherwise (the list is
+ *		empty), a new iag will be allocated for the ag to contain
+ *		the extent.
+ *		
+ *		once an iag has been selected, the free extent summary map
+ *		is used to locate a free extent within the iag and diNewExt()
+ *		is called to initialize the extent, with initialization
+ *		including the allocation of the first inode of the extent
+ *		for the purpose of satisfying this request.
+ *
+ * PARAMETERS:
+ *      imap  	- pointer to inode map control structure.
+ *      agno  	- allocation group number.
+ *      ip  	- pointer to new inode to be filled in on successful return
+ *		  with the disk inode number allocated, its extent address
+ *		  and the start of the ag.
+ *
+ * RETURN VALUES:
+ *      0       - success.
+ *      -ENOSPC	- insufficient disk resources.
+ *      -EIO  	- i/o error.
+ */
+static int diAllocExt(struct inomap * imap, int agno, struct inode *ip)
+{
+	int rem, iagno, sword, extno, rc;
+	struct metapage *mp;
+	struct iag *iagp;
+
+	/* check if the ag has any iags with free extents.  if not,
+	 * allocate a new iag for the ag.
+	 */
+	if ((iagno = imap->im_agctl[agno].extfree) < 0) {
+		/* If successful, diNewIAG will obtain the read lock on the
+		 * imap inode.
+		 */
+		if ((rc = diNewIAG(imap, &iagno, agno, &mp))) {
+			return (rc);
+		}
+		iagp = (struct iag *) mp->data;
+
+		/* set the ag number if this a brand new iag
+		 */
+		iagp->agstart =
+		    cpu_to_le64(AGTOBLK(agno, imap->im_ipimap));
+	} else {
+		/* read the iag.
+		 */
+		IREAD_LOCK(imap->im_ipimap);
+		if ((rc = diIAGRead(imap, iagno, &mp))) {
+			IREAD_UNLOCK(imap->im_ipimap);
+			jfs_error(ip->i_sb, "diAllocExt: error reading iag");
+			return rc;
+		}
+		iagp = (struct iag *) mp->data;
+	}
+
+	/* using the free extent summary map, find a free extent.
+	 */
+	for (sword = 0;; sword++) {
+		if (sword >= SMAPSZ) {
+			release_metapage(mp);
+			IREAD_UNLOCK(imap->im_ipimap);
+			jfs_error(ip->i_sb,
+				  "diAllocExt: free ext summary map not found");
+			return -EIO;
+		}
+		if (~iagp->extsmap[sword])
+			break;
+	}
+
+	/* determine the extent number of the free extent.
+	 */
+	rem = diFindFree(le32_to_cpu(iagp->extsmap[sword]), 0);
+	if (rem >= EXTSPERSUM) {
+		release_metapage(mp);
+		IREAD_UNLOCK(imap->im_ipimap);
+		jfs_error(ip->i_sb, "diAllocExt: free extent not found");
+		return -EIO;
+	}
+	extno = (sword << L2EXTSPERSUM) + rem;
+
+	/* initialize the new extent.
+	 */
+	rc = diNewExt(imap, iagp, extno);
+	IREAD_UNLOCK(imap->im_ipimap);
+	if (rc) {
+		/* something bad happened.  if a new iag was allocated,
+		 * place it back on the inode map's iag free list, and
+		 * clear the ag number information.
+		 */
+		if (iagp->nfreeexts == cpu_to_le32(EXTSPERIAG)) {
+			IAGFREE_LOCK(imap);
+			iagp->iagfree = cpu_to_le32(imap->im_freeiag);
+			imap->im_freeiag = iagno;
+			IAGFREE_UNLOCK(imap);
+		}
+		write_metapage(mp);
+		return (rc);
+	}
+
+	/* set the results of the allocation and write the iag.
+	 */
+	diInitInode(ip, iagno, extno << L2INOSPEREXT, extno, iagp);
+
+	write_metapage(mp);
+
+	return (0);
+}
+
+
+/*
+ * NAME:        diAllocBit(imap,iagp,ino)
+ *
+ * FUNCTION:   	allocate a backed inode from an iag.
+ *
+ *		this routine performs the mechanics of allocating a
+ *		specified inode from a backed extent.
+ *
+ *		if the inode to be allocated represents the last free
+ *		inode within the iag, the iag will be removed from the
+ *		ag free inode list.
+ *
+ *		a careful update approach is used to provide consistency
+ *		in the face of updates to multiple buffers.  under this
+ *		approach, all required buffers are obtained before making
+ *		any updates and are held all are updates are complete.
+ *		
+ * PRE CONDITION: Already have buffer lock on iagp.  Already have AG lock on
+ *	this AG.  Must have read lock on imap inode.
+ *
+ * PARAMETERS:
+ *      imap  	- pointer to inode map control structure.
+ *      iagp  	- pointer to iag. 
+ *      ino   	- inode number to be allocated within the iag.
+ *
+ * RETURN VALUES:
+ *      0       - success.
+ *      -ENOSPC	- insufficient disk resources.
+ *      -EIO  	- i/o error.
+ */
+static int diAllocBit(struct inomap * imap, struct iag * iagp, int ino)
+{
+	int extno, bitno, agno, sword, rc;
+	struct metapage *amp = NULL, *bmp = NULL;
+	struct iag *aiagp = NULL, *biagp = NULL;
+	u32 mask;
+
+	/* check if this is the last free inode within the iag.
+	 * if so, it will have to be removed from the ag free
+	 * inode list, so get the iags preceeding and following
+	 * it on the list.
+	 */
+	if (iagp->nfreeinos == cpu_to_le32(1)) {
+		if ((int) le32_to_cpu(iagp->inofreefwd) >= 0) {
+			if ((rc =
+			     diIAGRead(imap, le32_to_cpu(iagp->inofreefwd),
+				       &amp)))
+				return (rc);
+			aiagp = (struct iag *) amp->data;
+		}
+
+		if ((int) le32_to_cpu(iagp->inofreeback) >= 0) {
+			if ((rc =
+			     diIAGRead(imap,
+				       le32_to_cpu(iagp->inofreeback),
+				       &bmp))) {
+				if (amp)
+					release_metapage(amp);
+				return (rc);
+			}
+			biagp = (struct iag *) bmp->data;
+		}
+	}
+
+	/* get the ag number, extent number, inode number within
+	 * the extent.
+	 */
+	agno = BLKTOAG(le64_to_cpu(iagp->agstart), JFS_SBI(imap->im_ipimap->i_sb));
+	extno = ino >> L2INOSPEREXT;
+	bitno = ino & (INOSPEREXT - 1);
+
+	/* compute the mask for setting the map.
+	 */
+	mask = HIGHORDER >> bitno;
+
+	/* the inode should be free and backed.
+	 */
+	if (((le32_to_cpu(iagp->pmap[extno]) & mask) != 0) ||
+	    ((le32_to_cpu(iagp->wmap[extno]) & mask) != 0) ||
+	    (addressPXD(&iagp->inoext[extno]) == 0)) {
+		if (amp)
+			release_metapage(amp);
+		if (bmp)
+			release_metapage(bmp);
+
+		jfs_error(imap->im_ipimap->i_sb,
+			  "diAllocBit: iag inconsistent");
+		return -EIO;
+	}
+
+	/* mark the inode as allocated in the working map.
+	 */
+	iagp->wmap[extno] |= cpu_to_le32(mask);
+
+	/* check if all inodes within the extent are now
+	 * allocated.  if so, update the free inode summary
+	 * map to reflect this.
+	 */
+	if (iagp->wmap[extno] == cpu_to_le32(ONES)) {
+		sword = extno >> L2EXTSPERSUM;
+		bitno = extno & (EXTSPERSUM - 1);
+		iagp->inosmap[sword] |= cpu_to_le32(HIGHORDER >> bitno);
+	}
+
+	/* if this was the last free inode in the iag, remove the
+	 * iag from the ag free inode list.
+	 */
+	if (iagp->nfreeinos == cpu_to_le32(1)) {
+		if (amp) {
+			aiagp->inofreeback = iagp->inofreeback;
+			write_metapage(amp);
+		}
+
+		if (bmp) {
+			biagp->inofreefwd = iagp->inofreefwd;
+			write_metapage(bmp);
+		} else {
+			imap->im_agctl[agno].inofree =
+			    le32_to_cpu(iagp->inofreefwd);
+		}
+		iagp->inofreefwd = iagp->inofreeback = cpu_to_le32(-1);
+	}
+
+	/* update the free inode count at the iag, ag, inode
+	 * map levels.
+	 */
+	iagp->nfreeinos = cpu_to_le32(le32_to_cpu(iagp->nfreeinos) - 1);
+	imap->im_agctl[agno].numfree -= 1;
+	atomic_dec(&imap->im_numfree);
+
+	return (0);
+}
+
+
+/*
+ * NAME:        diNewExt(imap,iagp,extno)
+ *
+ * FUNCTION:    initialize a new extent of inodes for an iag, allocating
+ *	        the first inode of the extent for use for the current
+ *	        allocation request.
+ *
+ *		disk resources are allocated for the new extent of inodes
+ *		and the inodes themselves are initialized to reflect their
+ *		existence within the extent (i.e. their inode numbers and
+ *		inode extent addresses are set) and their initial state
+ *		(mode and link count are set to zero).
+ *
+ *		if the iag is new, it is not yet on an ag extent free list
+ *		but will now be placed on this list.
+ *
+ *		if the allocation of the new extent causes the iag to
+ *		have no free extent, the iag will be removed from the
+ *		ag extent free list.
+ *
+ *		if the iag has no free backed inodes, it will be placed
+ *		on the ag free inode list, since the addition of the new
+ *		extent will now cause it to have free inodes.
+ *
+ *		a careful update approach is used to provide consistency
+ *		(i.e. list consistency) in the face of updates to multiple
+ *		buffers.  under this approach, all required buffers are
+ *		obtained before making any updates and are held until all
+ *		updates are complete.
+ *		
+ * PRE CONDITION: Already have buffer lock on iagp.  Already have AG lock on
+ *	this AG.  Must have read lock on imap inode.
+ *
+ * PARAMETERS:
+ *      imap  	- pointer to inode map control structure.
+ *      iagp  	- pointer to iag. 
+ *      extno  	- extent number.
+ *
+ * RETURN VALUES:
+ *      0       - success.
+ *      -ENOSPC	- insufficient disk resources.
+ *      -EIO  	- i/o error.
+ */
+static int diNewExt(struct inomap * imap, struct iag * iagp, int extno)
+{
+	int agno, iagno, fwd, back, freei = 0, sword, rc;
+	struct iag *aiagp = NULL, *biagp = NULL, *ciagp = NULL;
+	struct metapage *amp, *bmp, *cmp, *dmp;
+	struct inode *ipimap;
+	s64 blkno, hint;
+	int i, j;
+	u32 mask;
+	ino_t ino;
+	struct dinode *dp;
+	struct jfs_sb_info *sbi;
+
+	/* better have free extents.
+	 */
+	if (!iagp->nfreeexts) {
+		jfs_error(imap->im_ipimap->i_sb, "diNewExt: no free extents");
+		return -EIO;
+	}
+
+	/* get the inode map inode.
+	 */
+	ipimap = imap->im_ipimap;
+	sbi = JFS_SBI(ipimap->i_sb);
+
+	amp = bmp = cmp = NULL;
+
+	/* get the ag and iag numbers for this iag.
+	 */
+	agno = BLKTOAG(le64_to_cpu(iagp->agstart), sbi);
+	iagno = le32_to_cpu(iagp->iagnum);
+
+	/* check if this is the last free extent within the
+	 * iag.  if so, the iag must be removed from the ag
+	 * free extent list, so get the iags preceeding and
+	 * following the iag on this list.
+	 */
+	if (iagp->nfreeexts == cpu_to_le32(1)) {
+		if ((fwd = le32_to_cpu(iagp->extfreefwd)) >= 0) {
+			if ((rc = diIAGRead(imap, fwd, &amp)))
+				return (rc);
+			aiagp = (struct iag *) amp->data;
+		}
+
+		if ((back = le32_to_cpu(iagp->extfreeback)) >= 0) {
+			if ((rc = diIAGRead(imap, back, &bmp)))
+				goto error_out;
+			biagp = (struct iag *) bmp->data;
+		}
+	} else {
+		/* the iag has free extents.  if all extents are free
+		 * (as is the case for a newly allocated iag), the iag
+		 * must be added to the ag free extent list, so get
+		 * the iag at the head of the list in preparation for
+		 * adding this iag to this list.
+		 */
+		fwd = back = -1;
+		if (iagp->nfreeexts == cpu_to_le32(EXTSPERIAG)) {
+			if ((fwd = imap->im_agctl[agno].extfree) >= 0) {
+				if ((rc = diIAGRead(imap, fwd, &amp)))
+					goto error_out;
+				aiagp = (struct iag *) amp->data;
+			}
+		}
+	}
+
+	/* check if the iag has no free inodes.  if so, the iag
+	 * will have to be added to the ag free inode list, so get
+	 * the iag at the head of the list in preparation for
+	 * adding this iag to this list.  in doing this, we must
+	 * check if we already have the iag at the head of
+	 * the list in hand.
+	 */
+	if (iagp->nfreeinos == 0) {
+		freei = imap->im_agctl[agno].inofree;
+
+		if (freei >= 0) {
+			if (freei == fwd) {
+				ciagp = aiagp;
+			} else if (freei == back) {
+				ciagp = biagp;
+			} else {
+				if ((rc = diIAGRead(imap, freei, &cmp)))
+					goto error_out;
+				ciagp = (struct iag *) cmp->data;
+			}
+			if (ciagp == NULL) {
+				jfs_error(imap->im_ipimap->i_sb,
+					  "diNewExt: ciagp == NULL");
+				rc = -EIO;
+				goto error_out;
+			}
+		}
+	}
+
+	/* allocate disk space for the inode extent.
+	 */
+	if ((extno == 0) || (addressPXD(&iagp->inoext[extno - 1]) == 0))
+		hint = ((s64) agno << sbi->bmap->db_agl2size) - 1;
+	else
+		hint = addressPXD(&iagp->inoext[extno - 1]) +
+		    lengthPXD(&iagp->inoext[extno - 1]) - 1;
+
+	if ((rc = dbAlloc(ipimap, hint, (s64) imap->im_nbperiext, &blkno)))
+		goto error_out;
+
+	/* compute the inode number of the first inode within the
+	 * extent.
+	 */
+	ino = (iagno << L2INOSPERIAG) + (extno << L2INOSPEREXT);
+
+	/* initialize the inodes within the newly allocated extent a
+	 * page at a time.
+	 */
+	for (i = 0; i < imap->im_nbperiext; i += sbi->nbperpage) {
+		/* get a buffer for this page of disk inodes.
+		 */
+		dmp = get_metapage(ipimap, blkno + i, PSIZE, 1);
+		if (dmp == NULL) {
+			rc = -EIO;
+			goto error_out;
+		}
+		dp = (struct dinode *) dmp->data;
+
+		/* initialize the inode number, mode, link count and
+		 * inode extent address.
+		 */
+		for (j = 0; j < INOSPERPAGE; j++, dp++, ino++) {
+			dp->di_inostamp = cpu_to_le32(sbi->inostamp);
+			dp->di_number = cpu_to_le32(ino);
+			dp->di_fileset = cpu_to_le32(FILESYSTEM_I);
+			dp->di_mode = 0;
+			dp->di_nlink = 0;
+			PXDaddress(&(dp->di_ixpxd), blkno);
+			PXDlength(&(dp->di_ixpxd), imap->im_nbperiext);
+		}
+		write_metapage(dmp);
+	}
+
+	/* if this is the last free extent within the iag, remove the
+	 * iag from the ag free extent list.
+	 */
+	if (iagp->nfreeexts == cpu_to_le32(1)) {
+		if (fwd >= 0)
+			aiagp->extfreeback = iagp->extfreeback;
+
+		if (back >= 0)
+			biagp->extfreefwd = iagp->extfreefwd;
+		else
+			imap->im_agctl[agno].extfree =
+			    le32_to_cpu(iagp->extfreefwd);
+
+		iagp->extfreefwd = iagp->extfreeback = cpu_to_le32(-1);
+	} else {
+		/* if the iag has all free extents (newly allocated iag),
+		 * add the iag to the ag free extent list.
+		 */
+		if (iagp->nfreeexts == cpu_to_le32(EXTSPERIAG)) {
+			if (fwd >= 0)
+				aiagp->extfreeback = cpu_to_le32(iagno);
+
+			iagp->extfreefwd = cpu_to_le32(fwd);
+			iagp->extfreeback = cpu_to_le32(-1);
+			imap->im_agctl[agno].extfree = iagno;
+		}
+	}
+
+	/* if the iag has no free inodes, add the iag to the
+	 * ag free inode list.
+	 */
+	if (iagp->nfreeinos == 0) {
+		if (freei >= 0)
+			ciagp->inofreeback = cpu_to_le32(iagno);
+
+		iagp->inofreefwd =
+		    cpu_to_le32(imap->im_agctl[agno].inofree);
+		iagp->inofreeback = cpu_to_le32(-1);
+		imap->im_agctl[agno].inofree = iagno;
+	}
+
+	/* initialize the extent descriptor of the extent. */
+	PXDlength(&iagp->inoext[extno], imap->im_nbperiext);
+	PXDaddress(&iagp->inoext[extno], blkno);
+
+	/* initialize the working and persistent map of the extent.
+	 * the working map will be initialized such that
+	 * it indicates the first inode of the extent is allocated.
+	 */
+	iagp->wmap[extno] = cpu_to_le32(HIGHORDER);
+	iagp->pmap[extno] = 0;
+
+	/* update the free inode and free extent summary maps
+	 * for the extent to indicate the extent has free inodes
+	 * and no longer represents a free extent.
+	 */
+	sword = extno >> L2EXTSPERSUM;
+	mask = HIGHORDER >> (extno & (EXTSPERSUM - 1));
+	iagp->extsmap[sword] |= cpu_to_le32(mask);
+	iagp->inosmap[sword] &= cpu_to_le32(~mask);
+
+	/* update the free inode and free extent counts for the
+	 * iag.
+	 */
+	iagp->nfreeinos = cpu_to_le32(le32_to_cpu(iagp->nfreeinos) +
+				      (INOSPEREXT - 1));
+	iagp->nfreeexts = cpu_to_le32(le32_to_cpu(iagp->nfreeexts) - 1);
+
+	/* update the free and backed inode counts for the ag.
+	 */
+	imap->im_agctl[agno].numfree += (INOSPEREXT - 1);
+	imap->im_agctl[agno].numinos += INOSPEREXT;
+
+	/* update the free and backed inode counts for the inode map.
+	 */
+	atomic_add(INOSPEREXT - 1, &imap->im_numfree);
+	atomic_add(INOSPEREXT, &imap->im_numinos);
+
+	/* write the iags.
+	 */
+	if (amp)
+		write_metapage(amp);
+	if (bmp)
+		write_metapage(bmp);
+	if (cmp)
+		write_metapage(cmp);
+
+	return (0);
+
+      error_out:
+
+	/* release the iags.
+	 */
+	if (amp)
+		release_metapage(amp);
+	if (bmp)
+		release_metapage(bmp);
+	if (cmp)
+		release_metapage(cmp);
+
+	return (rc);
+}
+
+
+/*
+ * NAME:        diNewIAG(imap,iagnop,agno)
+ *
+ * FUNCTION:   	allocate a new iag for an allocation group.
+ *		
+ *		first tries to allocate the iag from the inode map 
+ *		iagfree list:  
+ *		if the list has free iags, the head of the list is removed 
+ *		and returned to satisfy the request.
+ *		if the inode map's iag free list is empty, the inode map
+ *		is extended to hold a new iag. this new iag is initialized
+ *		and returned to satisfy the request.
+ *
+ * PARAMETERS:
+ *      imap  	- pointer to inode map control structure.
+ *      iagnop 	- pointer to an iag number set with the number of the
+ *		  newly allocated iag upon successful return.
+ *      agno  	- allocation group number.
+ *	bpp	- Buffer pointer to be filled in with new IAG's buffer
+ *
+ * RETURN VALUES:
+ *      0       - success.
+ *      -ENOSPC	- insufficient disk resources.
+ *      -EIO  	- i/o error.
+ *
+ * serialization: 
+ *	AG lock held on entry/exit;
+ *	write lock on the map is held inside;
+ *	read lock on the map is held on successful completion;
+ *
+ * note: new iag transaction: 
+ * . synchronously write iag;
+ * . write log of xtree and inode  of imap;
+ * . commit;
+ * . synchronous write of xtree (right to left, bottom to top);
+ * . at start of logredo(): init in-memory imap with one additional iag page;
+ * . at end of logredo(): re-read imap inode to determine
+ *   new imap size;
+ */
+static int
+diNewIAG(struct inomap * imap, int *iagnop, int agno, struct metapage ** mpp)
+{
+	int rc;
+	int iagno, i, xlen;
+	struct inode *ipimap;
+	struct super_block *sb;
+	struct jfs_sb_info *sbi;
+	struct metapage *mp;
+	struct iag *iagp;
+	s64 xaddr = 0;
+	s64 blkno;
+	tid_t tid;
+#ifdef _STILL_TO_PORT
+	xad_t xad;
+#endif				/*  _STILL_TO_PORT */
+	struct inode *iplist[1];
+
+	/* pick up pointers to the inode map and mount inodes */
+	ipimap = imap->im_ipimap;
+	sb = ipimap->i_sb;
+	sbi = JFS_SBI(sb);
+
+	/* acquire the free iag lock */
+	IAGFREE_LOCK(imap);
+
+	/* if there are any iags on the inode map free iag list, 
+	 * allocate the iag from the head of the list.
+	 */
+	if (imap->im_freeiag >= 0) {
+		/* pick up the iag number at the head of the list */
+		iagno = imap->im_freeiag;
+
+		/* determine the logical block number of the iag */
+		blkno = IAGTOLBLK(iagno, sbi->l2nbperpage);
+	} else {
+		/* no free iags. the inode map will have to be extented
+		 * to include a new iag.
+		 */
+
+		/* acquire inode map lock */
+		IWRITE_LOCK(ipimap);
+
+		if (ipimap->i_size >> L2PSIZE != imap->im_nextiag + 1) {
+			IWRITE_UNLOCK(ipimap);
+			IAGFREE_UNLOCK(imap);
+			jfs_error(imap->im_ipimap->i_sb,
+				  "diNewIAG: ipimap->i_size is wrong");
+			return -EIO;
+		}
+
+
+		/* get the next avaliable iag number */
+		iagno = imap->im_nextiag;
+
+		/* make sure that we have not exceeded the maximum inode
+		 * number limit.
+		 */
+		if (iagno > (MAXIAGS - 1)) {
+			/* release the inode map lock */
+			IWRITE_UNLOCK(ipimap);
+
+			rc = -ENOSPC;
+			goto out;
+		}
+
+		/*
+		 * synchronously append new iag page.
+		 */
+		/* determine the logical address of iag page to append */
+		blkno = IAGTOLBLK(iagno, sbi->l2nbperpage);
+
+		/* Allocate extent for new iag page */
+		xlen = sbi->nbperpage;
+		if ((rc = dbAlloc(ipimap, 0, (s64) xlen, &xaddr))) {
+			/* release the inode map lock */
+			IWRITE_UNLOCK(ipimap);
+
+			goto out;
+		}
+
+		/* assign a buffer for the page */
+		mp = get_metapage(ipimap, xaddr, PSIZE, 1);
+		if (!mp) {
+			/* Free the blocks allocated for the iag since it was
+			 * not successfully added to the inode map
+			 */
+			dbFree(ipimap, xaddr, (s64) xlen);
+
+			/* release the inode map lock */
+			IWRITE_UNLOCK(ipimap);
+
+			rc = -EIO;
+			goto out;
+		}
+		iagp = (struct iag *) mp->data;
+
+		/* init the iag */
+		memset(iagp, 0, sizeof(struct iag));
+		iagp->iagnum = cpu_to_le32(iagno);
+		iagp->inofreefwd = iagp->inofreeback = cpu_to_le32(-1);
+		iagp->extfreefwd = iagp->extfreeback = cpu_to_le32(-1);
+		iagp->iagfree = cpu_to_le32(-1);
+		iagp->nfreeinos = 0;
+		iagp->nfreeexts = cpu_to_le32(EXTSPERIAG);
+
+		/* initialize the free inode summary map (free extent
+		 * summary map initialization handled by bzero).
+		 */
+		for (i = 0; i < SMAPSZ; i++)
+			iagp->inosmap[i] = cpu_to_le32(ONES);
+
+		/*
+		 * Invalidate the page after writing and syncing it.
+		 * After it's initialized, we access it in a different
+		 * address space
+		 */
+		set_bit(META_discard, &mp->flag);
+		flush_metapage(mp);
+
+		/*
+		 * start tyransaction of update of the inode map
+		 * addressing structure pointing to the new iag page;
+		 */
+		tid = txBegin(sb, COMMIT_FORCE);
+		down(&JFS_IP(ipimap)->commit_sem);
+
+		/* update the inode map addressing structure to point to it */
+		if ((rc =
+		     xtInsert(tid, ipimap, 0, blkno, xlen, &xaddr, 0))) {
+			txEnd(tid);
+			up(&JFS_IP(ipimap)->commit_sem);
+			/* Free the blocks allocated for the iag since it was
+			 * not successfully added to the inode map
+			 */
+			dbFree(ipimap, xaddr, (s64) xlen);
+
+			/* release the inode map lock */
+			IWRITE_UNLOCK(ipimap);
+
+			goto out;
+		}
+
+		/* update the inode map's inode to reflect the extension */
+		ipimap->i_size += PSIZE;
+		inode_add_bytes(ipimap, PSIZE);
+
+		/*
+		 * txCommit(COMMIT_FORCE) will synchronously write address 
+		 * index pages and inode after commit in careful update order 
+		 * of address index pages (right to left, bottom up);
+		 */
+		iplist[0] = ipimap;
+		rc = txCommit(tid, 1, &iplist[0], COMMIT_FORCE);
+
+		txEnd(tid);
+		up(&JFS_IP(ipimap)->commit_sem);
+
+		duplicateIXtree(sb, blkno, xlen, &xaddr);
+
+		/* update the next avaliable iag number */
+		imap->im_nextiag += 1;
+
+		/* Add the iag to the iag free list so we don't lose the iag
+		 * if a failure happens now.
+		 */
+		imap->im_freeiag = iagno;
+
+		/* Until we have logredo working, we want the imap inode &
+		 * control page to be up to date.
+		 */
+		diSync(ipimap);
+
+		/* release the inode map lock */
+		IWRITE_UNLOCK(ipimap);
+	}
+
+	/* obtain read lock on map */
+	IREAD_LOCK(ipimap);
+
+	/* read the iag */
+	if ((rc = diIAGRead(imap, iagno, &mp))) {
+		IREAD_UNLOCK(ipimap);
+		rc = -EIO;
+		goto out;
+	}
+	iagp = (struct iag *) mp->data;
+
+	/* remove the iag from the iag free list */
+	imap->im_freeiag = le32_to_cpu(iagp->iagfree);
+	iagp->iagfree = cpu_to_le32(-1);
+
+	/* set the return iag number and buffer pointer */
+	*iagnop = iagno;
+	*mpp = mp;
+
+      out:
+	/* release the iag free lock */
+	IAGFREE_UNLOCK(imap);
+
+	return (rc);
+}
+
+/*
+ * NAME:        diIAGRead()
+ *
+ * FUNCTION:    get the buffer for the specified iag within a fileset
+ *		or aggregate inode map.
+ *		
+ * PARAMETERS:
+ *      imap  	- pointer to inode map control structure.
+ *      iagno  	- iag number.
+ *      bpp  	- point to buffer pointer to be filled in on successful
+ *		  exit.
+ *
+ * SERIALIZATION:
+ *	must have read lock on imap inode
+ *	(When called by diExtendFS, the filesystem is quiesced, therefore
+ *	 the read lock is unnecessary.)
+ *
+ * RETURN VALUES:
+ *      0       - success.
+ *      -EIO  	- i/o error.
+ */
+static int diIAGRead(struct inomap * imap, int iagno, struct metapage ** mpp)
+{
+	struct inode *ipimap = imap->im_ipimap;
+	s64 blkno;
+
+	/* compute the logical block number of the iag. */
+	blkno = IAGTOLBLK(iagno, JFS_SBI(ipimap->i_sb)->l2nbperpage);
+
+	/* read the iag. */
+	*mpp = read_metapage(ipimap, blkno, PSIZE, 0);
+	if (*mpp == NULL) {
+		return -EIO;
+	}
+
+	return (0);
+}
+
+/*
+ * NAME:        diFindFree()
+ *
+ * FUNCTION:    find the first free bit in a word starting at
+ *		the specified bit position.
+ *
+ * PARAMETERS:
+ *      word  	- word to be examined.
+ *      start  	- starting bit position.
+ *
+ * RETURN VALUES:
+ *      bit position of first free bit in the word or 32 if
+ *	no free bits were found.
+ */
+static int diFindFree(u32 word, int start)
+{
+	int bitno;
+	assert(start < 32);
+	/* scan the word for the first free bit. */
+	for (word <<= start, bitno = start; bitno < 32;
+	     bitno++, word <<= 1) {
+		if ((word & HIGHORDER) == 0)
+			break;
+	}
+	return (bitno);
+}
+
+/*
+ * NAME:	diUpdatePMap()
+ *                                                                    
+ * FUNCTION: Update the persistent map in an IAG for the allocation or 
+ *	freeing of the specified inode.
+ *                                                                    
+ * PRE CONDITIONS: Working map has already been updated for allocate.
+ *
+ * PARAMETERS:
+ *	ipimap	- Incore inode map inode
+ *	inum	- Number of inode to mark in permanent map
+ *	is_free	- If TRUE indicates inode should be marked freed, otherwise
+ *		  indicates inode should be marked allocated.
+ *
+ * RETURN VALUES: 
+ *		0 for success
+ */
+int
+diUpdatePMap(struct inode *ipimap,
+	     unsigned long inum, boolean_t is_free, struct tblock * tblk)
+{
+	int rc;
+	struct iag *iagp;
+	struct metapage *mp;
+	int iagno, ino, extno, bitno;
+	struct inomap *imap;
+	u32 mask;
+	struct jfs_log *log;
+	int lsn, difft, diffp;
+
+	imap = JFS_IP(ipimap)->i_imap;
+	/* get the iag number containing the inode */
+	iagno = INOTOIAG(inum);
+	/* make sure that the iag is contained within the map */
+	if (iagno >= imap->im_nextiag) {
+		jfs_error(ipimap->i_sb,
+			  "diUpdatePMap: the iag is outside the map");
+		return -EIO;
+	}
+	/* read the iag */
+	IREAD_LOCK(ipimap);
+	rc = diIAGRead(imap, iagno, &mp);
+	IREAD_UNLOCK(ipimap);
+	if (rc)
+		return (rc);
+	iagp = (struct iag *) mp->data;
+	/* get the inode number and extent number of the inode within
+	 * the iag and the inode number within the extent.
+	 */
+	ino = inum & (INOSPERIAG - 1);
+	extno = ino >> L2INOSPEREXT;
+	bitno = ino & (INOSPEREXT - 1);
+	mask = HIGHORDER >> bitno;
+	/* 
+	 * mark the inode free in persistent map:
+	 */
+	if (is_free == TRUE) {
+		/* The inode should have been allocated both in working
+		 * map and in persistent map;
+		 * the inode will be freed from working map at the release
+		 * of last reference release;
+		 */
+		if (!(le32_to_cpu(iagp->wmap[extno]) & mask)) {
+			jfs_error(ipimap->i_sb, 
+				  "diUpdatePMap: inode %ld not marked as "
+				  "allocated in wmap!", inum);
+		}
+		if (!(le32_to_cpu(iagp->pmap[extno]) & mask)) {
+			jfs_error(ipimap->i_sb,
+				  "diUpdatePMap: inode %ld not marked as "
+				  "allocated in pmap!", inum);
+		}
+		/* update the bitmap for the extent of the freed inode */
+		iagp->pmap[extno] &= cpu_to_le32(~mask);
+	}
+	/*
+	 * mark the inode allocated in persistent map:
+	 */
+	else {
+		/* The inode should be already allocated in the working map
+		 * and should be free in persistent map;
+		 */
+		if (!(le32_to_cpu(iagp->wmap[extno]) & mask)) {
+			release_metapage(mp);
+			jfs_error(ipimap->i_sb,
+				  "diUpdatePMap: the inode is not allocated in "
+				  "the working map");
+			return -EIO;
+		}
+		if ((le32_to_cpu(iagp->pmap[extno]) & mask) != 0) {
+			release_metapage(mp);
+			jfs_error(ipimap->i_sb,
+				  "diUpdatePMap: the inode is not free in the "
+				  "persistent map");
+			return -EIO;
+		}
+		/* update the bitmap for the extent of the allocated inode */
+		iagp->pmap[extno] |= cpu_to_le32(mask);
+	}
+	/*
+	 * update iag lsn
+	 */
+	lsn = tblk->lsn;
+	log = JFS_SBI(tblk->sb)->log;
+	if (mp->lsn != 0) {
+		/* inherit older/smaller lsn */
+		logdiff(difft, lsn, log);
+		logdiff(diffp, mp->lsn, log);
+		if (difft < diffp) {
+			mp->lsn = lsn;
+			/* move mp after tblock in logsync list */
+			LOGSYNC_LOCK(log);
+			list_move(&mp->synclist, &tblk->synclist);
+			LOGSYNC_UNLOCK(log);
+		}
+		/* inherit younger/larger clsn */
+		LOGSYNC_LOCK(log);
+		assert(mp->clsn);
+		logdiff(difft, tblk->clsn, log);
+		logdiff(diffp, mp->clsn, log);
+		if (difft > diffp)
+			mp->clsn = tblk->clsn;
+		LOGSYNC_UNLOCK(log);
+	} else {
+		mp->log = log;
+		mp->lsn = lsn;
+		/* insert mp after tblock in logsync list */
+		LOGSYNC_LOCK(log);
+		log->count++;
+		list_add(&mp->synclist, &tblk->synclist);
+		mp->clsn = tblk->clsn;
+		LOGSYNC_UNLOCK(log);
+	}
+	write_metapage(mp);
+	return (0);
+}
+
+/*
+ *	diExtendFS()
+ *
+ * function: update imap for extendfs();
+ * 
+ * note: AG size has been increased s.t. each k old contiguous AGs are 
+ * coalesced into a new AG;
+ */
+int diExtendFS(struct inode *ipimap, struct inode *ipbmap)
+{
+	int rc, rcx = 0;
+	struct inomap *imap = JFS_IP(ipimap)->i_imap;
+	struct iag *iagp = NULL, *hiagp = NULL;
+	struct bmap *mp = JFS_SBI(ipbmap->i_sb)->bmap;
+	struct metapage *bp, *hbp;
+	int i, n, head;
+	int numinos, xnuminos = 0, xnumfree = 0;
+	s64 agstart;
+
+	jfs_info("diExtendFS: nextiag:%d numinos:%d numfree:%d",
+		   imap->im_nextiag, atomic_read(&imap->im_numinos),
+		   atomic_read(&imap->im_numfree));
+
+	/*
+	 *      reconstruct imap 
+	 *
+	 * coalesce contiguous k (newAGSize/oldAGSize) AGs;
+	 * i.e., (AGi, ..., AGj) where i = k*n and j = k*(n+1) - 1 to AGn;
+	 * note: new AG size = old AG size * (2**x).
+	 */
+
+	/* init per AG control information im_agctl[] */
+	for (i = 0; i < MAXAG; i++) {
+		imap->im_agctl[i].inofree = -1;
+		imap->im_agctl[i].extfree = -1;
+		imap->im_agctl[i].numinos = 0;	/* number of backed inodes */
+		imap->im_agctl[i].numfree = 0;	/* number of free backed inodes */
+	}
+
+	/*
+	 *      process each iag page of the map.
+	 *
+	 * rebuild AG Free Inode List, AG Free Inode Extent List;
+	 */
+	for (i = 0; i < imap->im_nextiag; i++) {
+		if ((rc = diIAGRead(imap, i, &bp))) {
+			rcx = rc;
+			continue;
+		}
+		iagp = (struct iag *) bp->data;
+		if (le32_to_cpu(iagp->iagnum) != i) {
+			release_metapage(bp);
+			jfs_error(ipimap->i_sb,
+				  "diExtendFs: unexpected value of iagnum");
+			return -EIO;
+		}
+
+		/* leave free iag in the free iag list */
+		if (iagp->nfreeexts == cpu_to_le32(EXTSPERIAG)) {  
+		        release_metapage(bp);
+			continue;
+		}
+
+		/* agstart that computes to the same ag is treated as same; */
+		agstart = le64_to_cpu(iagp->agstart);
+		/* iagp->agstart = agstart & ~(mp->db_agsize - 1); */
+		n = agstart >> mp->db_agl2size;
+
+		/* compute backed inodes */
+		numinos = (EXTSPERIAG - le32_to_cpu(iagp->nfreeexts))
+		    << L2INOSPEREXT;
+		if (numinos > 0) {
+			/* merge AG backed inodes */
+			imap->im_agctl[n].numinos += numinos;
+			xnuminos += numinos;
+		}
+
+		/* if any backed free inodes, insert at AG free inode list */
+		if ((int) le32_to_cpu(iagp->nfreeinos) > 0) {
+			if ((head = imap->im_agctl[n].inofree) == -1) {
+				iagp->inofreefwd = cpu_to_le32(-1);
+				iagp->inofreeback = cpu_to_le32(-1);
+			} else {
+				if ((rc = diIAGRead(imap, head, &hbp))) {
+					rcx = rc;
+					goto nextiag;
+				}
+				hiagp = (struct iag *) hbp->data;
+				hiagp->inofreeback = iagp->iagnum;
+				iagp->inofreefwd = cpu_to_le32(head);
+				iagp->inofreeback = cpu_to_le32(-1);
+				write_metapage(hbp);
+			}
+
+			imap->im_agctl[n].inofree =
+			    le32_to_cpu(iagp->iagnum);
+
+			/* merge AG backed free inodes */
+			imap->im_agctl[n].numfree +=
+			    le32_to_cpu(iagp->nfreeinos);
+			xnumfree += le32_to_cpu(iagp->nfreeinos);
+		}
+
+		/* if any free extents, insert at AG free extent list */
+		if (le32_to_cpu(iagp->nfreeexts) > 0) {
+			if ((head = imap->im_agctl[n].extfree) == -1) {
+				iagp->extfreefwd = cpu_to_le32(-1);
+				iagp->extfreeback = cpu_to_le32(-1);
+			} else {
+				if ((rc = diIAGRead(imap, head, &hbp))) {
+					rcx = rc;
+					goto nextiag;
+				}
+				hiagp = (struct iag *) hbp->data;
+				hiagp->extfreeback = iagp->iagnum;
+				iagp->extfreefwd = cpu_to_le32(head);
+				iagp->extfreeback = cpu_to_le32(-1);
+				write_metapage(hbp);
+			}
+
+			imap->im_agctl[n].extfree =
+			    le32_to_cpu(iagp->iagnum);
+		}
+
+	      nextiag:
+		write_metapage(bp);
+	}
+
+	if (xnuminos != atomic_read(&imap->im_numinos) ||
+	    xnumfree != atomic_read(&imap->im_numfree)) {
+		jfs_error(ipimap->i_sb,
+			  "diExtendFs: numinos or numfree incorrect");
+		return -EIO;
+	}
+
+	return rcx;
+}
+
+
+/*
+ *	duplicateIXtree()
+ *
+ * serialization: IWRITE_LOCK held on entry/exit
+ *
+ * note: shadow page with regular inode (rel.2);
+ */
+static void duplicateIXtree(struct super_block *sb, s64 blkno,
+			    int xlen, s64 *xaddr)
+{
+	struct jfs_superblock *j_sb;
+	struct buffer_head *bh;
+	struct inode *ip;
+	tid_t tid;
+
+	/* if AIT2 ipmap2 is bad, do not try to update it */
+	if (JFS_SBI(sb)->mntflag & JFS_BAD_SAIT)	/* s_flag */
+		return;
+	ip = diReadSpecial(sb, FILESYSTEM_I, 1);
+	if (ip == NULL) {
+		JFS_SBI(sb)->mntflag |= JFS_BAD_SAIT;
+		if (readSuper(sb, &bh))
+			return;
+		j_sb = (struct jfs_superblock *)bh->b_data;
+		j_sb->s_flag |= cpu_to_le32(JFS_BAD_SAIT);
+
+		mark_buffer_dirty(bh);
+		sync_dirty_buffer(bh);
+		brelse(bh);
+		return;
+	}
+
+	/* start transaction */
+	tid = txBegin(sb, COMMIT_FORCE);
+	/* update the inode map addressing structure to point to it */
+	if (xtInsert(tid, ip, 0, blkno, xlen, xaddr, 0)) {
+		JFS_SBI(sb)->mntflag |= JFS_BAD_SAIT;
+		txAbort(tid, 1);
+		goto cleanup;
+
+	}
+	/* update the inode map's inode to reflect the extension */
+	ip->i_size += PSIZE;
+	inode_add_bytes(ip, PSIZE);
+	txCommit(tid, 1, &ip, COMMIT_FORCE);
+      cleanup:
+	txEnd(tid);
+	diFreeSpecial(ip);
+}
+
+/*
+ * NAME:        copy_from_dinode()
+ *
+ * FUNCTION:    Copies inode info from disk inode to in-memory inode
+ *
+ * RETURN VALUES:
+ *      0       - success
+ *      -ENOMEM	- insufficient memory
+ */
+static int copy_from_dinode(struct dinode * dip, struct inode *ip)
+{
+	struct jfs_inode_info *jfs_ip = JFS_IP(ip);
+
+	jfs_ip->fileset = le32_to_cpu(dip->di_fileset);
+	jfs_ip->mode2 = le32_to_cpu(dip->di_mode);
+
+	ip->i_mode = le32_to_cpu(dip->di_mode) & 0xffff;
+	ip->i_nlink = le32_to_cpu(dip->di_nlink);
+	ip->i_uid = le32_to_cpu(dip->di_uid);
+	ip->i_gid = le32_to_cpu(dip->di_gid);
+	ip->i_size = le64_to_cpu(dip->di_size);
+	ip->i_atime.tv_sec = le32_to_cpu(dip->di_atime.tv_sec);
+	ip->i_atime.tv_nsec = le32_to_cpu(dip->di_atime.tv_nsec);
+	ip->i_mtime.tv_sec = le32_to_cpu(dip->di_mtime.tv_sec);
+	ip->i_mtime.tv_nsec = le32_to_cpu(dip->di_mtime.tv_nsec);
+	ip->i_ctime.tv_sec = le32_to_cpu(dip->di_ctime.tv_sec);
+	ip->i_ctime.tv_nsec = le32_to_cpu(dip->di_ctime.tv_nsec);
+	ip->i_blksize = ip->i_sb->s_blocksize;
+	ip->i_blocks = LBLK2PBLK(ip->i_sb, le64_to_cpu(dip->di_nblocks));
+	ip->i_generation = le32_to_cpu(dip->di_gen);
+
+	jfs_ip->ixpxd = dip->di_ixpxd;	/* in-memory pxd's are little-endian */
+	jfs_ip->acl = dip->di_acl;	/* as are dxd's */
+	jfs_ip->ea = dip->di_ea;
+	jfs_ip->next_index = le32_to_cpu(dip->di_next_index);
+	jfs_ip->otime = le32_to_cpu(dip->di_otime.tv_sec);
+	jfs_ip->acltype = le32_to_cpu(dip->di_acltype);
+
+	if (S_ISCHR(ip->i_mode) || S_ISBLK(ip->i_mode)) {
+		jfs_ip->dev = le32_to_cpu(dip->di_rdev);
+		ip->i_rdev = new_decode_dev(jfs_ip->dev);
+	}
+
+	if (S_ISDIR(ip->i_mode)) {
+		memcpy(&jfs_ip->i_dirtable, &dip->di_dirtable, 384);
+	} else if (S_ISREG(ip->i_mode) || S_ISLNK(ip->i_mode)) {
+		memcpy(&jfs_ip->i_xtroot, &dip->di_xtroot, 288);
+	} else
+		memcpy(&jfs_ip->i_inline_ea, &dip->di_inlineea, 128);
+
+	/* Zero the in-memory-only stuff */
+	jfs_ip->cflag = 0;
+	jfs_ip->btindex = 0;
+	jfs_ip->btorder = 0;
+	jfs_ip->bxflag = 0;
+	jfs_ip->blid = 0;
+	jfs_ip->atlhead = 0;
+	jfs_ip->atltail = 0;
+	jfs_ip->xtlid = 0;
+	return (0);
+}
+
+/*
+ * NAME:        copy_to_dinode()
+ *
+ * FUNCTION:    Copies inode info from in-memory inode to disk inode
+ */
+static void copy_to_dinode(struct dinode * dip, struct inode *ip)
+{
+	struct jfs_inode_info *jfs_ip = JFS_IP(ip);
+
+	dip->di_fileset = cpu_to_le32(jfs_ip->fileset);
+	dip->di_inostamp = cpu_to_le32(JFS_SBI(ip->i_sb)->inostamp);
+	dip->di_number = cpu_to_le32(ip->i_ino);
+	dip->di_gen = cpu_to_le32(ip->i_generation);
+	dip->di_size = cpu_to_le64(ip->i_size);
+	dip->di_nblocks = cpu_to_le64(PBLK2LBLK(ip->i_sb, ip->i_blocks));
+	dip->di_nlink = cpu_to_le32(ip->i_nlink);
+	dip->di_uid = cpu_to_le32(ip->i_uid);
+	dip->di_gid = cpu_to_le32(ip->i_gid);
+	/*
+	 * mode2 is only needed for storing the higher order bits.
+	 * Trust i_mode for the lower order ones
+	 */
+	dip->di_mode = cpu_to_le32((jfs_ip->mode2 & 0xffff0000) | ip->i_mode);
+	dip->di_atime.tv_sec = cpu_to_le32(ip->i_atime.tv_sec);
+	dip->di_atime.tv_nsec = cpu_to_le32(ip->i_atime.tv_nsec);
+	dip->di_ctime.tv_sec = cpu_to_le32(ip->i_ctime.tv_sec);
+	dip->di_ctime.tv_nsec = cpu_to_le32(ip->i_ctime.tv_nsec);
+	dip->di_mtime.tv_sec = cpu_to_le32(ip->i_mtime.tv_sec);
+	dip->di_mtime.tv_nsec = cpu_to_le32(ip->i_mtime.tv_nsec);
+	dip->di_ixpxd = jfs_ip->ixpxd;	/* in-memory pxd's are little-endian */
+	dip->di_acl = jfs_ip->acl;	/* as are dxd's */
+	dip->di_ea = jfs_ip->ea;
+	dip->di_next_index = cpu_to_le32(jfs_ip->next_index);
+	dip->di_otime.tv_sec = cpu_to_le32(jfs_ip->otime);
+	dip->di_otime.tv_nsec = 0;
+	dip->di_acltype = cpu_to_le32(jfs_ip->acltype);
+	if (S_ISCHR(ip->i_mode) || S_ISBLK(ip->i_mode))
+		dip->di_rdev = cpu_to_le32(jfs_ip->dev);
+}
+
+#ifdef	_JFS_DEBUG_IMAP
+/*
+ *	DBGdiInit()
+ */
+static void *DBGdiInit(struct inomap * imap)
+{
+	u32 *dimap;
+	int size;
+	size = 64 * 1024;
+	if ((dimap = (u32 *) xmalloc(size, L2PSIZE, kernel_heap)) == NULL)
+		assert(0);
+	bzero((void *) dimap, size);
+	imap->im_DBGdimap = dimap;
+}
+
+/*
+ *	DBGdiAlloc()
+ */
+static void DBGdiAlloc(struct inomap * imap, ino_t ino)
+{
+	u32 *dimap = imap->im_DBGdimap;
+	int w, b;
+	u32 m;
+	w = ino >> 5;
+	b = ino & 31;
+	m = 0x80000000 >> b;
+	assert(w < 64 * 256);
+	if (dimap[w] & m) {
+		printk("DEBUG diAlloc: duplicate alloc ino:0x%x\n", ino);
+	}
+	dimap[w] |= m;
+}
+
+/*
+ *	DBGdiFree()
+ */
+static void DBGdiFree(struct inomap * imap, ino_t ino)
+{
+	u32 *dimap = imap->im_DBGdimap;
+	int w, b;
+	u32 m;
+	w = ino >> 5;
+	b = ino & 31;
+	m = 0x80000000 >> b;
+	assert(w < 64 * 256);
+	if ((dimap[w] & m) == 0) {
+		printk("DEBUG diFree: duplicate free ino:0x%x\n", ino);
+	}
+	dimap[w] &= ~m;
+}
+
+static void dump_cp(struct inomap * ipimap, char *function, int line)
+{
+	printk("\n* ********* *\nControl Page %s %d\n", function, line);
+	printk("FreeIAG %d\tNextIAG %d\n", ipimap->im_freeiag,
+	       ipimap->im_nextiag);
+	printk("NumInos %d\tNumFree %d\n",
+	       atomic_read(&ipimap->im_numinos),
+	       atomic_read(&ipimap->im_numfree));
+	printk("AG InoFree %d\tAG ExtFree %d\n",
+	       ipimap->im_agctl[0].inofree, ipimap->im_agctl[0].extfree);
+	printk("AG NumInos %d\tAG NumFree %d\n",
+	       ipimap->im_agctl[0].numinos, ipimap->im_agctl[0].numfree);
+}
+
+static void dump_iag(struct iag * iag, char *function, int line)
+{
+	printk("\n* ********* *\nIAG %s %d\n", function, line);
+	printk("IagNum %d\tIAG Free %d\n", le32_to_cpu(iag->iagnum),
+	       le32_to_cpu(iag->iagfree));
+	printk("InoFreeFwd %d\tInoFreeBack %d\n",
+	       le32_to_cpu(iag->inofreefwd),
+	       le32_to_cpu(iag->inofreeback));
+	printk("ExtFreeFwd %d\tExtFreeBack %d\n",
+	       le32_to_cpu(iag->extfreefwd),
+	       le32_to_cpu(iag->extfreeback));
+	printk("NFreeInos %d\tNFreeExts %d\n", le32_to_cpu(iag->nfreeinos),
+	       le32_to_cpu(iag->nfreeexts));
+}
+#endif				/* _JFS_DEBUG_IMAP */