Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 4264 insertions, 0 deletions

diff --git a/fs/jfs/jfs_dtree.c b/fs/jfs/jfs_dtree.c
new file mode 100644
index 000000000..92b7c5334
--- /dev/null
+++ b/fs/jfs/jfs_dtree.c
@@ -0,0 +1,4264 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *   Copyright (C) International Business Machines Corp., 2000-2004
+ */
+
+/*
+ *	jfs_dtree.c: directory B+-tree manager
+ *
+ * B+-tree with variable length key directory:
+ *
+ * each directory page is structured as an array of 32-byte
+ * directory entry slots initialized as a freelist
+ * to avoid search/compaction of free space at insertion.
+ * when an entry is inserted, a number of slots are allocated
+ * from the freelist as required to store variable length data
+ * of the entry; when the entry is deleted, slots of the entry
+ * are returned to freelist.
+ *
+ * leaf entry stores full name as key and file serial number
+ * (aka inode number) as data.
+ * internal/router entry stores sufffix compressed name
+ * as key and simple extent descriptor as data.
+ *
+ * each directory page maintains a sorted entry index table
+ * which stores the start slot index of sorted entries
+ * to allow binary search on the table.
+ *
+ * directory starts as a root/leaf page in on-disk inode
+ * inline data area.
+ * when it becomes full, it starts a leaf of a external extent
+ * of length of 1 block. each time the first leaf becomes full,
+ * it is extended rather than split (its size is doubled),
+ * until its length becoms 4 KBytes, from then the extent is split
+ * with new 4 Kbyte extent when it becomes full
+ * to reduce external fragmentation of small directories.
+ *
+ * blah, blah, blah, for linear scan of directory in pieces by
+ * readdir().
+ *
+ *
+ *	case-insensitive directory file system
+ *
+ * names are stored in case-sensitive way in leaf entry.
+ * but stored, searched and compared in case-insensitive (uppercase) order
+ * (i.e., both search key and entry key are folded for search/compare):
+ * (note that case-sensitive order is BROKEN in storage, e.g.,
+ *  sensitive: Ad, aB, aC, aD -> insensitive: aB, aC, aD, Ad
+ *
+ *  entries which folds to the same key makes up a equivalent class
+ *  whose members are stored as contiguous cluster (may cross page boundary)
+ *  but whose order is arbitrary and acts as duplicate, e.g.,
+ *  abc, Abc, aBc, abC)
+ *
+ * once match is found at leaf, requires scan forward/backward
+ * either for, in case-insensitive search, duplicate
+ * or for, in case-sensitive search, for exact match
+ *
+ * router entry must be created/stored in case-insensitive way
+ * in internal entry:
+ * (right most key of left page and left most key of right page
+ * are folded, and its suffix compression is propagated as router
+ * key in parent)
+ * (e.g., if split occurs <abc> and <aBd>, <ABD> trather than <aB>
+ * should be made the router key for the split)
+ *
+ * case-insensitive search:
+ *
+ *	fold search key;
+ *
+ *	case-insensitive search of B-tree:
+ *	for internal entry, router key is already folded;
+ *	for leaf entry, fold the entry key before comparison.
+ *
+ *	if (leaf entry case-insensitive match found)
+ *		if (next entry satisfies case-insensitive match)
+ *			return EDUPLICATE;
+ *		if (prev entry satisfies case-insensitive match)
+ *			return EDUPLICATE;
+ *		return match;
+ *	else
+ *		return no match;
+ *
+ *	serialization:
+ * target directory inode lock is being held on entry/exit
+ * of all main directory service routines.
+ *
+ *	log based recovery:
+ */
+
+#include <linux/fs.h>
+#include <linux/quotaops.h>
+#include <linux/slab.h>
+#include "jfs_incore.h"
+#include "jfs_superblock.h"
+#include "jfs_filsys.h"
+#include "jfs_metapage.h"
+#include "jfs_dmap.h"
+#include "jfs_unicode.h"
+#include "jfs_debug.h"
+
+/* dtree split parameter */
+struct dtsplit {
+	struct metapage *mp;
+	s16 index;
+	s16 nslot;
+	struct component_name *key;
+	ddata_t *data;
+	struct pxdlist *pxdlist;
+};
+
+#define DT_PAGE(IP, MP) BT_PAGE(IP, MP, dtpage_t, i_dtroot)
+
+/* get page buffer for specified block address */
+#define DT_GETPAGE(IP, BN, MP, SIZE, P, RC)				\
+do {									\
+	BT_GETPAGE(IP, BN, MP, dtpage_t, SIZE, P, RC, i_dtroot);	\
+	if (!(RC)) {							\
+		if (((P)->header.nextindex >				\
+		     (((BN) == 0) ? DTROOTMAXSLOT : (P)->header.maxslot)) || \
+		    ((BN) && ((P)->header.maxslot > DTPAGEMAXSLOT))) {	\
+			BT_PUTPAGE(MP);					\
+			jfs_error((IP)->i_sb,				\
+				  "DT_GETPAGE: dtree page corrupt\n");	\
+			MP = NULL;					\
+			RC = -EIO;					\
+		}							\
+	}								\
+} while (0)
+
+/* for consistency */
+#define DT_PUTPAGE(MP) BT_PUTPAGE(MP)
+
+#define DT_GETSEARCH(IP, LEAF, BN, MP, P, INDEX) \
+	BT_GETSEARCH(IP, LEAF, BN, MP, dtpage_t, P, INDEX, i_dtroot)
+
+/*
+ * forward references
+ */
+static int dtSplitUp(tid_t tid, struct inode *ip,
+		     struct dtsplit * split, struct btstack * btstack);
+
+static int dtSplitPage(tid_t tid, struct inode *ip, struct dtsplit * split,
+		       struct metapage ** rmpp, dtpage_t ** rpp, pxd_t * rxdp);
+
+static int dtExtendPage(tid_t tid, struct inode *ip,
+			struct dtsplit * split, struct btstack * btstack);
+
+static int dtSplitRoot(tid_t tid, struct inode *ip,
+		       struct dtsplit * split, struct metapage ** rmpp);
+
+static int dtDeleteUp(tid_t tid, struct inode *ip, struct metapage * fmp,
+		      dtpage_t * fp, struct btstack * btstack);
+
+static int dtRelink(tid_t tid, struct inode *ip, dtpage_t * p);
+
+static int dtReadFirst(struct inode *ip, struct btstack * btstack);
+
+static int dtReadNext(struct inode *ip,
+		      loff_t * offset, struct btstack * btstack);
+
+static int dtCompare(struct component_name * key, dtpage_t * p, int si);
+
+static int ciCompare(struct component_name * key, dtpage_t * p, int si,
+		     int flag);
+
+static void dtGetKey(dtpage_t * p, int i, struct component_name * key,
+		     int flag);
+
+static int ciGetLeafPrefixKey(dtpage_t * lp, int li, dtpage_t * rp,
+			      int ri, struct component_name * key, int flag);
+
+static void dtInsertEntry(dtpage_t * p, int index, struct component_name * key,
+			  ddata_t * data, struct dt_lock **);
+
+static void dtMoveEntry(dtpage_t * sp, int si, dtpage_t * dp,
+			struct dt_lock ** sdtlock, struct dt_lock ** ddtlock,
+			int do_index);
+
+static void dtDeleteEntry(dtpage_t * p, int fi, struct dt_lock ** dtlock);
+
+static void dtTruncateEntry(dtpage_t * p, int ti, struct dt_lock ** dtlock);
+
+static void dtLinelockFreelist(dtpage_t * p, int m, struct dt_lock ** dtlock);
+
+#define ciToUpper(c)	UniStrupr((c)->name)
+
+/*
+ *	read_index_page()
+ *
+ *	Reads a page of a directory's index table.
+ *	Having metadata mapped into the directory inode's address space
+ *	presents a multitude of problems.  We avoid this by mapping to
+ *	the absolute address space outside of the *_metapage routines
+ */
+static struct metapage *read_index_page(struct inode *inode, s64 blkno)
+{
+	int rc;
+	s64 xaddr;
+	int xflag;
+	s32 xlen;
+
+	rc = xtLookup(inode, blkno, 1, &xflag, &xaddr, &xlen, 1);
+	if (rc || (xaddr == 0))
+		return NULL;
+
+	return read_metapage(inode, xaddr, PSIZE, 1);
+}
+
+/*
+ *	get_index_page()
+ *
+ *	Same as get_index_page(), but get's a new page without reading
+ */
+static struct metapage *get_index_page(struct inode *inode, s64 blkno)
+{
+	int rc;
+	s64 xaddr;
+	int xflag;
+	s32 xlen;
+
+	rc = xtLookup(inode, blkno, 1, &xflag, &xaddr, &xlen, 1);
+	if (rc || (xaddr == 0))
+		return NULL;
+
+	return get_metapage(inode, xaddr, PSIZE, 1);
+}
+
+/*
+ *	find_index()
+ *
+ *	Returns dtree page containing directory table entry for specified
+ *	index and pointer to its entry.
+ *
+ *	mp must be released by caller.
+ */
+static struct dir_table_slot *find_index(struct inode *ip, u32 index,
+					 struct metapage ** mp, s64 *lblock)
+{
+	struct jfs_inode_info *jfs_ip = JFS_IP(ip);
+	s64 blkno;
+	s64 offset;
+	int page_offset;
+	struct dir_table_slot *slot;
+	static int maxWarnings = 10;
+
+	if (index < 2) {
+		if (maxWarnings) {
+			jfs_warn("find_entry called with index = %d", index);
+			maxWarnings--;
+		}
+		return NULL;
+	}
+
+	if (index >= jfs_ip->next_index) {
+		jfs_warn("find_entry called with index >= next_index");
+		return NULL;
+	}
+
+	if (jfs_dirtable_inline(ip)) {
+		/*
+		 * Inline directory table
+		 */
+		*mp = NULL;
+		slot = &jfs_ip->i_dirtable[index - 2];
+	} else {
+		offset = (index - 2) * sizeof(struct dir_table_slot);
+		page_offset = offset & (PSIZE - 1);
+		blkno = ((offset + 1) >> L2PSIZE) <<
+		    JFS_SBI(ip->i_sb)->l2nbperpage;
+
+		if (*mp && (*lblock != blkno)) {
+			release_metapage(*mp);
+			*mp = NULL;
+		}
+		if (!(*mp)) {
+			*lblock = blkno;
+			*mp = read_index_page(ip, blkno);
+		}
+		if (!(*mp)) {
+			jfs_err("free_index: error reading directory table");
+			return NULL;
+		}
+
+		slot =
+		    (struct dir_table_slot *) ((char *) (*mp)->data +
+					       page_offset);
+	}
+	return slot;
+}
+
+static inline void lock_index(tid_t tid, struct inode *ip, struct metapage * mp,
+			      u32 index)
+{
+	struct tlock *tlck;
+	struct linelock *llck;
+	struct lv *lv;
+
+	tlck = txLock(tid, ip, mp, tlckDATA);
+	llck = (struct linelock *) tlck->lock;
+
+	if (llck->index >= llck->maxcnt)
+		llck = txLinelock(llck);
+	lv = &llck->lv[llck->index];
+
+	/*
+	 *	Linelock slot size is twice the size of directory table
+	 *	slot size.  512 entries per page.
+	 */
+	lv->offset = ((index - 2) & 511) >> 1;
+	lv->length = 1;
+	llck->index++;
+}
+
+/*
+ *	add_index()
+ *
+ *	Adds an entry to the directory index table.  This is used to provide
+ *	each directory entry with a persistent index in which to resume
+ *	directory traversals
+ */
+static u32 add_index(tid_t tid, struct inode *ip, s64 bn, int slot)
+{
+	struct super_block *sb = ip->i_sb;
+	struct jfs_sb_info *sbi = JFS_SBI(sb);
+	struct jfs_inode_info *jfs_ip = JFS_IP(ip);
+	u64 blkno;
+	struct dir_table_slot *dirtab_slot;
+	u32 index;
+	struct linelock *llck;
+	struct lv *lv;
+	struct metapage *mp;
+	s64 offset;
+	uint page_offset;
+	struct tlock *tlck;
+	s64 xaddr;
+
+	ASSERT(DO_INDEX(ip));
+
+	if (jfs_ip->next_index < 2) {
+		jfs_warn("add_index: next_index = %d.  Resetting!",
+			   jfs_ip->next_index);
+		jfs_ip->next_index = 2;
+	}
+
+	index = jfs_ip->next_index++;
+
+	if (index <= MAX_INLINE_DIRTABLE_ENTRY) {
+		/*
+		 * i_size reflects size of index table, or 8 bytes per entry.
+		 */
+		ip->i_size = (loff_t) (index - 1) << 3;
+
+		/*
+		 * dir table fits inline within inode
+		 */
+		dirtab_slot = &jfs_ip->i_dirtable[index-2];
+		dirtab_slot->flag = DIR_INDEX_VALID;
+		dirtab_slot->slot = slot;
+		DTSaddress(dirtab_slot, bn);
+
+		set_cflag(COMMIT_Dirtable, ip);
+
+		return index;
+	}
+	if (index == (MAX_INLINE_DIRTABLE_ENTRY + 1)) {
+		struct dir_table_slot temp_table[12];
+
+		/*
+		 * It's time to move the inline table to an external
+		 * page and begin to build the xtree
+		 */
+		if (dquot_alloc_block(ip, sbi->nbperpage))
+			goto clean_up;
+		if (dbAlloc(ip, 0, sbi->nbperpage, &xaddr)) {
+			dquot_free_block(ip, sbi->nbperpage);
+			goto clean_up;
+		}
+
+		/*
+		 * Save the table, we're going to overwrite it with the
+		 * xtree root
+		 */
+		memcpy(temp_table, &jfs_ip->i_dirtable, sizeof(temp_table));
+
+		/*
+		 * Initialize empty x-tree
+		 */
+		xtInitRoot(tid, ip);
+
+		/*
+		 * Add the first block to the xtree
+		 */
+		if (xtInsert(tid, ip, 0, 0, sbi->nbperpage, &xaddr, 0)) {
+			/* This really shouldn't fail */
+			jfs_warn("add_index: xtInsert failed!");
+			memcpy(&jfs_ip->i_dirtable, temp_table,
+			       sizeof (temp_table));
+			dbFree(ip, xaddr, sbi->nbperpage);
+			dquot_free_block(ip, sbi->nbperpage);
+			goto clean_up;
+		}
+		ip->i_size = PSIZE;
+
+		mp = get_index_page(ip, 0);
+		if (!mp) {
+			jfs_err("add_index: get_metapage failed!");
+			xtTruncate(tid, ip, 0, COMMIT_PWMAP);
+			memcpy(&jfs_ip->i_dirtable, temp_table,
+			       sizeof (temp_table));
+			goto clean_up;
+		}
+		tlck = txLock(tid, ip, mp, tlckDATA);
+		llck = (struct linelock *) & tlck->lock;
+		ASSERT(llck->index == 0);
+		lv = &llck->lv[0];
+
+		lv->offset = 0;
+		lv->length = 6;	/* tlckDATA slot size is 16 bytes */
+		llck->index++;
+
+		memcpy(mp->data, temp_table, sizeof(temp_table));
+
+		mark_metapage_dirty(mp);
+		release_metapage(mp);
+
+		/*
+		 * Logging is now directed by xtree tlocks
+		 */
+		clear_cflag(COMMIT_Dirtable, ip);
+	}
+
+	offset = (index - 2) * sizeof(struct dir_table_slot);
+	page_offset = offset & (PSIZE - 1);
+	blkno = ((offset + 1) >> L2PSIZE) << sbi->l2nbperpage;
+	if (page_offset == 0) {
+		/*
+		 * This will be the beginning of a new page
+		 */
+		xaddr = 0;
+		if (xtInsert(tid, ip, 0, blkno, sbi->nbperpage, &xaddr, 0)) {
+			jfs_warn("add_index: xtInsert failed!");
+			goto clean_up;
+		}
+		ip->i_size += PSIZE;
+
+		if ((mp = get_index_page(ip, blkno)))
+			memset(mp->data, 0, PSIZE);	/* Just looks better */
+		else
+			xtTruncate(tid, ip, offset, COMMIT_PWMAP);
+	} else
+		mp = read_index_page(ip, blkno);
+
+	if (!mp) {
+		jfs_err("add_index: get/read_metapage failed!");
+		goto clean_up;
+	}
+
+	lock_index(tid, ip, mp, index);
+
+	dirtab_slot =
+	    (struct dir_table_slot *) ((char *) mp->data + page_offset);
+	dirtab_slot->flag = DIR_INDEX_VALID;
+	dirtab_slot->slot = slot;
+	DTSaddress(dirtab_slot, bn);
+
+	mark_metapage_dirty(mp);
+	release_metapage(mp);
+
+	return index;
+
+      clean_up:
+
+	jfs_ip->next_index--;
+
+	return 0;
+}
+
+/*
+ *	free_index()
+ *
+ *	Marks an entry to the directory index table as free.
+ */
+static void free_index(tid_t tid, struct inode *ip, u32 index, u32 next)
+{
+	struct dir_table_slot *dirtab_slot;
+	s64 lblock;
+	struct metapage *mp = NULL;
+
+	dirtab_slot = find_index(ip, index, &mp, &lblock);
+
+	if (!dirtab_slot)
+		return;
+
+	dirtab_slot->flag = DIR_INDEX_FREE;
+	dirtab_slot->slot = dirtab_slot->addr1 = 0;
+	dirtab_slot->addr2 = cpu_to_le32(next);
+
+	if (mp) {
+		lock_index(tid, ip, mp, index);
+		mark_metapage_dirty(mp);
+		release_metapage(mp);
+	} else
+		set_cflag(COMMIT_Dirtable, ip);
+}
+
+/*
+ *	modify_index()
+ *
+ *	Changes an entry in the directory index table
+ */
+static void modify_index(tid_t tid, struct inode *ip, u32 index, s64 bn,
+			 int slot, struct metapage ** mp, s64 *lblock)
+{
+	struct dir_table_slot *dirtab_slot;
+
+	dirtab_slot = find_index(ip, index, mp, lblock);
+
+	if (!dirtab_slot)
+		return;
+
+	DTSaddress(dirtab_slot, bn);
+	dirtab_slot->slot = slot;
+
+	if (*mp) {
+		lock_index(tid, ip, *mp, index);
+		mark_metapage_dirty(*mp);
+	} else
+		set_cflag(COMMIT_Dirtable, ip);
+}
+
+/*
+ *	read_index()
+ *
+ *	reads a directory table slot
+ */
+static int read_index(struct inode *ip, u32 index,
+		     struct dir_table_slot * dirtab_slot)
+{
+	s64 lblock;
+	struct metapage *mp = NULL;
+	struct dir_table_slot *slot;
+
+	slot = find_index(ip, index, &mp, &lblock);
+	if (!slot) {
+		return -EIO;
+	}
+
+	memcpy(dirtab_slot, slot, sizeof(struct dir_table_slot));
+
+	if (mp)
+		release_metapage(mp);
+
+	return 0;
+}
+
+/*
+ *	dtSearch()
+ *
+ * function:
+ *	Search for the entry with specified key
+ *
+ * parameter:
+ *
+ * return: 0 - search result on stack, leaf page pinned;
+ *	   errno - I/O error
+ */
+int dtSearch(struct inode *ip, struct component_name * key, ino_t * data,
+	     struct btstack * btstack, int flag)
+{
+	int rc = 0;
+	int cmp = 1;		/* init for empty page */
+	s64 bn;
+	struct metapage *mp;
+	dtpage_t *p;
+	s8 *stbl;
+	int base, index, lim;
+	struct btframe *btsp;
+	pxd_t *pxd;
+	int psize = 288;	/* initial in-line directory */
+	ino_t inumber;
+	struct component_name ciKey;
+	struct super_block *sb = ip->i_sb;
+
+	ciKey.name = kmalloc_array(JFS_NAME_MAX + 1, sizeof(wchar_t),
+				   GFP_NOFS);
+	if (!ciKey.name) {
+		rc = -ENOMEM;
+		goto dtSearch_Exit2;
+	}
+
+
+	/* uppercase search key for c-i directory */
+	UniStrcpy(ciKey.name, key->name);
+	ciKey.namlen = key->namlen;
+
+	/* only uppercase if case-insensitive support is on */
+	if ((JFS_SBI(sb)->mntflag & JFS_OS2) == JFS_OS2) {
+		ciToUpper(&ciKey);
+	}
+	BT_CLR(btstack);	/* reset stack */
+
+	/* init level count for max pages to split */
+	btstack->nsplit = 1;
+
+	/*
+	 *	search down tree from root:
+	 *
+	 * between two consecutive entries of <Ki, Pi> and <Kj, Pj> of
+	 * internal page, child page Pi contains entry with k, Ki <= K < Kj.
+	 *
+	 * if entry with search key K is not found
+	 * internal page search find the entry with largest key Ki
+	 * less than K which point to the child page to search;
+	 * leaf page search find the entry with smallest key Kj
+	 * greater than K so that the returned index is the position of
+	 * the entry to be shifted right for insertion of new entry.
+	 * for empty tree, search key is greater than any key of the tree.
+	 *
+	 * by convention, root bn = 0.
+	 */
+	for (bn = 0;;) {
+		/* get/pin the page to search */
+		DT_GETPAGE(ip, bn, mp, psize, p, rc);
+		if (rc)
+			goto dtSearch_Exit1;
+
+		/* get sorted entry table of the page */
+		stbl = DT_GETSTBL(p);
+
+		/*
+		 * binary search with search key K on the current page.
+		 */
+		for (base = 0, lim = p->header.nextindex; lim; lim >>= 1) {
+			index = base + (lim >> 1);
+
+			if (p->header.flag & BT_LEAF) {
+				/* uppercase leaf name to compare */
+				cmp =
+				    ciCompare(&ciKey, p, stbl[index],
+					      JFS_SBI(sb)->mntflag);
+			} else {
+				/* router key is in uppercase */
+
+				cmp = dtCompare(&ciKey, p, stbl[index]);
+
+
+			}
+			if (cmp == 0) {
+				/*
+				 *	search hit
+				 */
+				/* search hit - leaf page:
+				 * return the entry found
+				 */
+				if (p->header.flag & BT_LEAF) {
+					inumber = le32_to_cpu(
+			((struct ldtentry *) & p->slot[stbl[index]])->inumber);
+
+					/*
+					 * search for JFS_LOOKUP
+					 */
+					if (flag == JFS_LOOKUP) {
+						*data = inumber;
+						rc = 0;
+						goto out;
+					}
+
+					/*
+					 * search for JFS_CREATE
+					 */
+					if (flag == JFS_CREATE) {
+						*data = inumber;
+						rc = -EEXIST;
+						goto out;
+					}
+
+					/*
+					 * search for JFS_REMOVE or JFS_RENAME
+					 */
+					if ((flag == JFS_REMOVE ||
+					     flag == JFS_RENAME) &&
+					    *data != inumber) {
+						rc = -ESTALE;
+						goto out;
+					}
+
+					/*
+					 * JFS_REMOVE|JFS_FINDDIR|JFS_RENAME
+					 */
+					/* save search result */
+					*data = inumber;
+					btsp = btstack->top;
+					btsp->bn = bn;
+					btsp->index = index;
+					btsp->mp = mp;
+
+					rc = 0;
+					goto dtSearch_Exit1;
+				}
+
+				/* search hit - internal page:
+				 * descend/search its child page
+				 */
+				goto getChild;
+			}
+
+			if (cmp > 0) {
+				base = index + 1;
+				--lim;
+			}
+		}
+
+		/*
+		 *	search miss
+		 *
+		 * base is the smallest index with key (Kj) greater than
+		 * search key (K) and may be zero or (maxindex + 1) index.
+		 */
+		/*
+		 * search miss - leaf page
+		 *
+		 * return location of entry (base) where new entry with
+		 * search key K is to be inserted.
+		 */
+		if (p->header.flag & BT_LEAF) {
+			/*
+			 * search for JFS_LOOKUP, JFS_REMOVE, or JFS_RENAME
+			 */
+			if (flag == JFS_LOOKUP || flag == JFS_REMOVE ||
+			    flag == JFS_RENAME) {
+				rc = -ENOENT;
+				goto out;
+			}
+
+			/*
+			 * search for JFS_CREATE|JFS_FINDDIR:
+			 *
+			 * save search result
+			 */
+			*data = 0;
+			btsp = btstack->top;
+			btsp->bn = bn;
+			btsp->index = base;
+			btsp->mp = mp;
+
+			rc = 0;
+			goto dtSearch_Exit1;
+		}
+
+		/*
+		 * search miss - internal page
+		 *
+		 * if base is non-zero, decrement base by one to get the parent
+		 * entry of the child page to search.
+		 */
+		index = base ? base - 1 : base;
+
+		/*
+		 * go down to child page
+		 */
+	      getChild:
+		/* update max. number of pages to split */
+		if (BT_STACK_FULL(btstack)) {
+			/* Something's corrupted, mark filesystem dirty so
+			 * chkdsk will fix it.
+			 */
+			jfs_error(sb, "stack overrun!\n");
+			BT_STACK_DUMP(btstack);
+			rc = -EIO;
+			goto out;
+		}
+		btstack->nsplit++;
+
+		/* push (bn, index) of the parent page/entry */
+		BT_PUSH(btstack, bn, index);
+
+		/* get the child page block number */
+		pxd = (pxd_t *) & p->slot[stbl[index]];
+		bn = addressPXD(pxd);
+		psize = lengthPXD(pxd) << JFS_SBI(ip->i_sb)->l2bsize;
+
+		/* unpin the parent page */
+		DT_PUTPAGE(mp);
+	}
+
+      out:
+	DT_PUTPAGE(mp);
+
+      dtSearch_Exit1:
+
+	kfree(ciKey.name);
+
+      dtSearch_Exit2:
+
+	return rc;
+}
+
+
+/*
+ *	dtInsert()
+ *
+ * function: insert an entry to directory tree
+ *
+ * parameter:
+ *
+ * return: 0 - success;
+ *	   errno - failure;
+ */
+int dtInsert(tid_t tid, struct inode *ip,
+	 struct component_name * name, ino_t * fsn, struct btstack * btstack)
+{
+	int rc = 0;
+	struct metapage *mp;	/* meta-page buffer */
+	dtpage_t *p;		/* base B+-tree index page */
+	s64 bn;
+	int index;
+	struct dtsplit split;	/* split information */
+	ddata_t data;
+	struct dt_lock *dtlck;
+	int n;
+	struct tlock *tlck;
+	struct lv *lv;
+
+	/*
+	 *	retrieve search result
+	 *
+	 * dtSearch() returns (leaf page pinned, index at which to insert).
+	 * n.b. dtSearch() may return index of (maxindex + 1) of
+	 * the full page.
+	 */
+	DT_GETSEARCH(ip, btstack->top, bn, mp, p, index);
+
+	/*
+	 *	insert entry for new key
+	 */
+	if (DO_INDEX(ip)) {
+		if (JFS_IP(ip)->next_index == DIREND) {
+			DT_PUTPAGE(mp);
+			return -EMLINK;
+		}
+		n = NDTLEAF(name->namlen);
+		data.leaf.tid = tid;
+		data.leaf.ip = ip;
+	} else {
+		n = NDTLEAF_LEGACY(name->namlen);
+		data.leaf.ip = NULL;	/* signifies legacy directory format */
+	}
+	data.leaf.ino = *fsn;
+
+	/*
+	 *	leaf page does not have enough room for new entry:
+	 *
+	 *	extend/split the leaf page;
+	 *
+	 * dtSplitUp() will insert the entry and unpin the leaf page.
+	 */
+	if (n > p->header.freecnt) {
+		split.mp = mp;
+		split.index = index;
+		split.nslot = n;
+		split.key = name;
+		split.data = &data;
+		rc = dtSplitUp(tid, ip, &split, btstack);
+		return rc;
+	}
+
+	/*
+	 *	leaf page does have enough room for new entry:
+	 *
+	 *	insert the new data entry into the leaf page;
+	 */
+	BT_MARK_DIRTY(mp, ip);
+	/*
+	 * acquire a transaction lock on the leaf page
+	 */
+	tlck = txLock(tid, ip, mp, tlckDTREE | tlckENTRY);
+	dtlck = (struct dt_lock *) & tlck->lock;
+	ASSERT(dtlck->index == 0);
+	lv = & dtlck->lv[0];
+
+	/* linelock header */
+	lv->offset = 0;
+	lv->length = 1;
+	dtlck->index++;
+
+	dtInsertEntry(p, index, name, &data, &dtlck);
+
+	/* linelock stbl of non-root leaf page */
+	if (!(p->header.flag & BT_ROOT)) {
+		if (dtlck->index >= dtlck->maxcnt)
+			dtlck = (struct dt_lock *) txLinelock(dtlck);
+		lv = & dtlck->lv[dtlck->index];
+		n = index >> L2DTSLOTSIZE;
+		lv->offset = p->header.stblindex + n;
+		lv->length =
+		    ((p->header.nextindex - 1) >> L2DTSLOTSIZE) - n + 1;
+		dtlck->index++;
+	}
+
+	/* unpin the leaf page */
+	DT_PUTPAGE(mp);
+
+	return 0;
+}
+
+
+/*
+ *	dtSplitUp()
+ *
+ * function: propagate insertion bottom up;
+ *
+ * parameter:
+ *
+ * return: 0 - success;
+ *	   errno - failure;
+ *	leaf page unpinned;
+ */
+static int dtSplitUp(tid_t tid,
+	  struct inode *ip, struct dtsplit * split, struct btstack * btstack)
+{
+	struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
+	int rc = 0;
+	struct metapage *smp;
+	dtpage_t *sp;		/* split page */
+	struct metapage *rmp;
+	dtpage_t *rp;		/* new right page split from sp */
+	pxd_t rpxd;		/* new right page extent descriptor */
+	struct metapage *lmp;
+	dtpage_t *lp;		/* left child page */
+	int skip;		/* index of entry of insertion */
+	struct btframe *parent;	/* parent page entry on traverse stack */
+	s64 xaddr, nxaddr;
+	int xlen, xsize;
+	struct pxdlist pxdlist;
+	pxd_t *pxd;
+	struct component_name key = { 0, NULL };
+	ddata_t *data = split->data;
+	int n;
+	struct dt_lock *dtlck;
+	struct tlock *tlck;
+	struct lv *lv;
+	int quota_allocation = 0;
+
+	/* get split page */
+	smp = split->mp;
+	sp = DT_PAGE(ip, smp);
+
+	key.name = kmalloc_array(JFS_NAME_MAX + 2, sizeof(wchar_t), GFP_NOFS);
+	if (!key.name) {
+		DT_PUTPAGE(smp);
+		rc = -ENOMEM;
+		goto dtSplitUp_Exit;
+	}
+
+	/*
+	 *	split leaf page
+	 *
+	 * The split routines insert the new entry, and
+	 * acquire txLock as appropriate.
+	 */
+	/*
+	 *	split root leaf page:
+	 */
+	if (sp->header.flag & BT_ROOT) {
+		/*
+		 * allocate a single extent child page
+		 */
+		xlen = 1;
+		n = sbi->bsize >> L2DTSLOTSIZE;
+		n -= (n + 31) >> L2DTSLOTSIZE;	/* stbl size */
+		n -= DTROOTMAXSLOT - sp->header.freecnt; /* header + entries */
+		if (n <= split->nslot)
+			xlen++;
+		if ((rc = dbAlloc(ip, 0, (s64) xlen, &xaddr))) {
+			DT_PUTPAGE(smp);
+			goto freeKeyName;
+		}
+
+		pxdlist.maxnpxd = 1;
+		pxdlist.npxd = 0;
+		pxd = &pxdlist.pxd[0];
+		PXDaddress(pxd, xaddr);
+		PXDlength(pxd, xlen);
+		split->pxdlist = &pxdlist;
+		rc = dtSplitRoot(tid, ip, split, &rmp);
+
+		if (rc)
+			dbFree(ip, xaddr, xlen);
+		else
+			DT_PUTPAGE(rmp);
+
+		DT_PUTPAGE(smp);
+
+		if (!DO_INDEX(ip))
+			ip->i_size = xlen << sbi->l2bsize;
+
+		goto freeKeyName;
+	}
+
+	/*
+	 *	extend first leaf page
+	 *
+	 * extend the 1st extent if less than buffer page size
+	 * (dtExtendPage() reurns leaf page unpinned)
+	 */
+	pxd = &sp->header.self;
+	xlen = lengthPXD(pxd);
+	xsize = xlen << sbi->l2bsize;
+	if (xsize < PSIZE) {
+		xaddr = addressPXD(pxd);
+		n = xsize >> L2DTSLOTSIZE;
+		n -= (n + 31) >> L2DTSLOTSIZE;	/* stbl size */
+		if ((n + sp->header.freecnt) <= split->nslot)
+			n = xlen + (xlen << 1);
+		else
+			n = xlen;
+
+		/* Allocate blocks to quota. */
+		rc = dquot_alloc_block(ip, n);
+		if (rc)
+			goto extendOut;
+		quota_allocation += n;
+
+		if ((rc = dbReAlloc(sbi->ipbmap, xaddr, (s64) xlen,
+				    (s64) n, &nxaddr)))
+			goto extendOut;
+
+		pxdlist.maxnpxd = 1;
+		pxdlist.npxd = 0;
+		pxd = &pxdlist.pxd[0];
+		PXDaddress(pxd, nxaddr);
+		PXDlength(pxd, xlen + n);
+		split->pxdlist = &pxdlist;
+		if ((rc = dtExtendPage(tid, ip, split, btstack))) {
+			nxaddr = addressPXD(pxd);
+			if (xaddr != nxaddr) {
+				/* free relocated extent */
+				xlen = lengthPXD(pxd);
+				dbFree(ip, nxaddr, (s64) xlen);
+			} else {
+				/* free extended delta */
+				xlen = lengthPXD(pxd) - n;
+				xaddr = addressPXD(pxd) + xlen;
+				dbFree(ip, xaddr, (s64) n);
+			}
+		} else if (!DO_INDEX(ip))
+			ip->i_size = lengthPXD(pxd) << sbi->l2bsize;
+
+
+	      extendOut:
+		DT_PUTPAGE(smp);
+		goto freeKeyName;
+	}
+
+	/*
+	 *	split leaf page <sp> into <sp> and a new right page <rp>.
+	 *
+	 * return <rp> pinned and its extent descriptor <rpxd>
+	 */
+	/*
+	 * allocate new directory page extent and
+	 * new index page(s) to cover page split(s)
+	 *
+	 * allocation hint: ?
+	 */
+	n = btstack->nsplit;
+	pxdlist.maxnpxd = pxdlist.npxd = 0;
+	xlen = sbi->nbperpage;
+	for (pxd = pxdlist.pxd; n > 0; n--, pxd++) {
+		if ((rc = dbAlloc(ip, 0, (s64) xlen, &xaddr)) == 0) {
+			PXDaddress(pxd, xaddr);
+			PXDlength(pxd, xlen);
+			pxdlist.maxnpxd++;
+			continue;
+		}
+
+		DT_PUTPAGE(smp);
+
+		/* undo allocation */
+		goto splitOut;
+	}
+
+	split->pxdlist = &pxdlist;
+	if ((rc = dtSplitPage(tid, ip, split, &rmp, &rp, &rpxd))) {
+		DT_PUTPAGE(smp);
+
+		/* undo allocation */
+		goto splitOut;
+	}
+
+	if (!DO_INDEX(ip))
+		ip->i_size += PSIZE;
+
+	/*
+	 * propagate up the router entry for the leaf page just split
+	 *
+	 * insert a router entry for the new page into the parent page,
+	 * propagate the insert/split up the tree by walking back the stack
+	 * of (bn of parent page, index of child page entry in parent page)
+	 * that were traversed during the search for the page that split.
+	 *
+	 * the propagation of insert/split up the tree stops if the root
+	 * splits or the page inserted into doesn't have to split to hold
+	 * the new entry.
+	 *
+	 * the parent entry for the split page remains the same, and
+	 * a new entry is inserted at its right with the first key and
+	 * block number of the new right page.
+	 *
+	 * There are a maximum of 4 pages pinned at any time:
+	 * two children, left parent and right parent (when the parent splits).
+	 * keep the child pages pinned while working on the parent.
+	 * make sure that all pins are released at exit.
+	 */
+	while ((parent = BT_POP(btstack)) != NULL) {
+		/* parent page specified by stack frame <parent> */
+
+		/* keep current child pages (<lp>, <rp>) pinned */
+		lmp = smp;
+		lp = sp;
+
+		/*
+		 * insert router entry in parent for new right child page <rp>
+		 */
+		/* get the parent page <sp> */
+		DT_GETPAGE(ip, parent->bn, smp, PSIZE, sp, rc);
+		if (rc) {
+			DT_PUTPAGE(lmp);
+			DT_PUTPAGE(rmp);
+			goto splitOut;
+		}
+
+		/*
+		 * The new key entry goes ONE AFTER the index of parent entry,
+		 * because the split was to the right.
+		 */
+		skip = parent->index + 1;
+
+		/*
+		 * compute the key for the router entry
+		 *
+		 * key suffix compression:
+		 * for internal pages that have leaf pages as children,
+		 * retain only what's needed to distinguish between
+		 * the new entry and the entry on the page to its left.
+		 * If the keys compare equal, retain the entire key.
+		 *
+		 * note that compression is performed only at computing
+		 * router key at the lowest internal level.
+		 * further compression of the key between pairs of higher
+		 * level internal pages loses too much information and
+		 * the search may fail.
+		 * (e.g., two adjacent leaf pages of {a, ..., x} {xx, ...,}
+		 * results in two adjacent parent entries (a)(xx).
+		 * if split occurs between these two entries, and
+		 * if compression is applied, the router key of parent entry
+		 * of right page (x) will divert search for x into right
+		 * subtree and miss x in the left subtree.)
+		 *
+		 * the entire key must be retained for the next-to-leftmost
+		 * internal key at any level of the tree, or search may fail
+		 * (e.g., ?)
+		 */
+		switch (rp->header.flag & BT_TYPE) {
+		case BT_LEAF:
+			/*
+			 * compute the length of prefix for suffix compression
+			 * between last entry of left page and first entry
+			 * of right page
+			 */
+			if ((sp->header.flag & BT_ROOT && skip > 1) ||
+			    sp->header.prev != 0 || skip > 1) {
+				/* compute uppercase router prefix key */
+				rc = ciGetLeafPrefixKey(lp,
+							lp->header.nextindex-1,
+							rp, 0, &key,
+							sbi->mntflag);
+				if (rc) {
+					DT_PUTPAGE(lmp);
+					DT_PUTPAGE(rmp);
+					DT_PUTPAGE(smp);
+					goto splitOut;
+				}
+			} else {
+				/* next to leftmost entry of
+				   lowest internal level */
+
+				/* compute uppercase router key */
+				dtGetKey(rp, 0, &key, sbi->mntflag);
+				key.name[key.namlen] = 0;
+
+				if ((sbi->mntflag & JFS_OS2) == JFS_OS2)
+					ciToUpper(&key);
+			}
+
+			n = NDTINTERNAL(key.namlen);
+			break;
+
+		case BT_INTERNAL:
+			dtGetKey(rp, 0, &key, sbi->mntflag);
+			n = NDTINTERNAL(key.namlen);
+			break;
+
+		default:
+			jfs_err("dtSplitUp(): UFO!");
+			break;
+		}
+
+		/* unpin left child page */
+		DT_PUTPAGE(lmp);
+
+		/*
+		 * compute the data for the router entry
+		 */
+		data->xd = rpxd;	/* child page xd */
+
+		/*
+		 * parent page is full - split the parent page
+		 */
+		if (n > sp->header.freecnt) {
+			/* init for parent page split */
+			split->mp = smp;
+			split->index = skip;	/* index at insert */
+			split->nslot = n;
+			split->key = &key;
+			/* split->data = data; */
+
+			/* unpin right child page */
+			DT_PUTPAGE(rmp);
+
+			/* The split routines insert the new entry,
+			 * acquire txLock as appropriate.
+			 * return <rp> pinned and its block number <rbn>.
+			 */
+			rc = (sp->header.flag & BT_ROOT) ?
+			    dtSplitRoot(tid, ip, split, &rmp) :
+			    dtSplitPage(tid, ip, split, &rmp, &rp, &rpxd);
+			if (rc) {
+				DT_PUTPAGE(smp);
+				goto splitOut;
+			}
+
+			/* smp and rmp are pinned */
+		}
+		/*
+		 * parent page is not full - insert router entry in parent page
+		 */
+		else {
+			BT_MARK_DIRTY(smp, ip);
+			/*
+			 * acquire a transaction lock on the parent page
+			 */
+			tlck = txLock(tid, ip, smp, tlckDTREE | tlckENTRY);
+			dtlck = (struct dt_lock *) & tlck->lock;
+			ASSERT(dtlck->index == 0);
+			lv = & dtlck->lv[0];
+
+			/* linelock header */
+			lv->offset = 0;
+			lv->length = 1;
+			dtlck->index++;
+
+			/* linelock stbl of non-root parent page */
+			if (!(sp->header.flag & BT_ROOT)) {
+				lv++;
+				n = skip >> L2DTSLOTSIZE;
+				lv->offset = sp->header.stblindex + n;
+				lv->length =
+				    ((sp->header.nextindex -
+				      1) >> L2DTSLOTSIZE) - n + 1;
+				dtlck->index++;
+			}
+
+			dtInsertEntry(sp, skip, &key, data, &dtlck);
+
+			/* exit propagate up */
+			break;
+		}
+	}
+
+	/* unpin current split and its right page */
+	DT_PUTPAGE(smp);
+	DT_PUTPAGE(rmp);
+
+	/*
+	 * free remaining extents allocated for split
+	 */
+      splitOut:
+	n = pxdlist.npxd;
+	pxd = &pxdlist.pxd[n];
+	for (; n < pxdlist.maxnpxd; n++, pxd++)
+		dbFree(ip, addressPXD(pxd), (s64) lengthPXD(pxd));
+
+      freeKeyName:
+	kfree(key.name);
+
+	/* Rollback quota allocation */
+	if (rc && quota_allocation)
+		dquot_free_block(ip, quota_allocation);
+
+      dtSplitUp_Exit:
+
+	return rc;
+}
+
+
+/*
+ *	dtSplitPage()
+ *
+ * function: Split a non-root page of a btree.
+ *
+ * parameter:
+ *
+ * return: 0 - success;
+ *	   errno - failure;
+ *	return split and new page pinned;
+ */
+static int dtSplitPage(tid_t tid, struct inode *ip, struct dtsplit * split,
+	    struct metapage ** rmpp, dtpage_t ** rpp, pxd_t * rpxdp)
+{
+	int rc = 0;
+	struct metapage *smp;
+	dtpage_t *sp;
+	struct metapage *rmp;
+	dtpage_t *rp;		/* new right page allocated */
+	s64 rbn;		/* new right page block number */
+	struct metapage *mp;
+	dtpage_t *p;
+	s64 nextbn;
+	struct pxdlist *pxdlist;
+	pxd_t *pxd;
+	int skip, nextindex, half, left, nxt, off, si;
+	struct ldtentry *ldtentry;
+	struct idtentry *idtentry;
+	u8 *stbl;
+	struct dtslot *f;
+	int fsi, stblsize;
+	int n;
+	struct dt_lock *sdtlck, *rdtlck;
+	struct tlock *tlck;
+	struct dt_lock *dtlck;
+	struct lv *slv, *rlv, *lv;
+
+	/* get split page */
+	smp = split->mp;
+	sp = DT_PAGE(ip, smp);
+
+	/*
+	 * allocate the new right page for the split
+	 */
+	pxdlist = split->pxdlist;
+	pxd = &pxdlist->pxd[pxdlist->npxd];
+	pxdlist->npxd++;
+	rbn = addressPXD(pxd);
+	rmp = get_metapage(ip, rbn, PSIZE, 1);
+	if (rmp == NULL)
+		return -EIO;
+
+	/* Allocate blocks to quota. */
+	rc = dquot_alloc_block(ip, lengthPXD(pxd));
+	if (rc) {
+		release_metapage(rmp);
+		return rc;
+	}
+
+	jfs_info("dtSplitPage: ip:0x%p smp:0x%p rmp:0x%p", ip, smp, rmp);
+
+	BT_MARK_DIRTY(rmp, ip);
+	/*
+	 * acquire a transaction lock on the new right page
+	 */
+	tlck = txLock(tid, ip, rmp, tlckDTREE | tlckNEW);
+	rdtlck = (struct dt_lock *) & tlck->lock;
+
+	rp = (dtpage_t *) rmp->data;
+	*rpp = rp;
+	rp->header.self = *pxd;
+
+	BT_MARK_DIRTY(smp, ip);
+	/*
+	 * acquire a transaction lock on the split page
+	 *
+	 * action:
+	 */
+	tlck = txLock(tid, ip, smp, tlckDTREE | tlckENTRY);
+	sdtlck = (struct dt_lock *) & tlck->lock;
+
+	/* linelock header of split page */
+	ASSERT(sdtlck->index == 0);
+	slv = & sdtlck->lv[0];
+	slv->offset = 0;
+	slv->length = 1;
+	sdtlck->index++;
+
+	/*
+	 * initialize/update sibling pointers between sp and rp
+	 */
+	nextbn = le64_to_cpu(sp->header.next);
+	rp->header.next = cpu_to_le64(nextbn);
+	rp->header.prev = cpu_to_le64(addressPXD(&sp->header.self));
+	sp->header.next = cpu_to_le64(rbn);
+
+	/*
+	 * initialize new right page
+	 */
+	rp->header.flag = sp->header.flag;
+
+	/* compute sorted entry table at start of extent data area */
+	rp->header.nextindex = 0;
+	rp->header.stblindex = 1;
+
+	n = PSIZE >> L2DTSLOTSIZE;
+	rp->header.maxslot = n;
+	stblsize = (n + 31) >> L2DTSLOTSIZE;	/* in unit of slot */
+
+	/* init freelist */
+	fsi = rp->header.stblindex + stblsize;
+	rp->header.freelist = fsi;
+	rp->header.freecnt = rp->header.maxslot - fsi;
+
+	/*
+	 *	sequential append at tail: append without split
+	 *
+	 * If splitting the last page on a level because of appending
+	 * a entry to it (skip is maxentry), it's likely that the access is
+	 * sequential. Adding an empty page on the side of the level is less
+	 * work and can push the fill factor much higher than normal.
+	 * If we're wrong it's no big deal, we'll just do the split the right
+	 * way next time.
+	 * (It may look like it's equally easy to do a similar hack for
+	 * reverse sorted data, that is, split the tree left,
+	 * but it's not. Be my guest.)
+	 */
+	if (nextbn == 0 && split->index == sp->header.nextindex) {
+		/* linelock header + stbl (first slot) of new page */
+		rlv = & rdtlck->lv[rdtlck->index];
+		rlv->offset = 0;
+		rlv->length = 2;
+		rdtlck->index++;
+
+		/*
+		 * initialize freelist of new right page
+		 */
+		f = &rp->slot[fsi];
+		for (fsi++; fsi < rp->header.maxslot; f++, fsi++)
+			f->next = fsi;
+		f->next = -1;
+
+		/* insert entry at the first entry of the new right page */
+		dtInsertEntry(rp, 0, split->key, split->data, &rdtlck);
+
+		goto out;
+	}
+
+	/*
+	 *	non-sequential insert (at possibly middle page)
+	 */
+
+	/*
+	 * update prev pointer of previous right sibling page;
+	 */
+	if (nextbn != 0) {
+		DT_GETPAGE(ip, nextbn, mp, PSIZE, p, rc);
+		if (rc) {
+			discard_metapage(rmp);
+			return rc;
+		}
+
+		BT_MARK_DIRTY(mp, ip);
+		/*
+		 * acquire a transaction lock on the next page
+		 */
+		tlck = txLock(tid, ip, mp, tlckDTREE | tlckRELINK);
+		jfs_info("dtSplitPage: tlck = 0x%p, ip = 0x%p, mp=0x%p",
+			tlck, ip, mp);
+		dtlck = (struct dt_lock *) & tlck->lock;
+
+		/* linelock header of previous right sibling page */
+		lv = & dtlck->lv[dtlck->index];
+		lv->offset = 0;
+		lv->length = 1;
+		dtlck->index++;
+
+		p->header.prev = cpu_to_le64(rbn);
+
+		DT_PUTPAGE(mp);
+	}
+
+	/*
+	 * split the data between the split and right pages.
+	 */
+	skip = split->index;
+	half = (PSIZE >> L2DTSLOTSIZE) >> 1;	/* swag */
+	left = 0;
+
+	/*
+	 *	compute fill factor for split pages
+	 *
+	 * <nxt> traces the next entry to move to rp
+	 * <off> traces the next entry to stay in sp
+	 */
+	stbl = (u8 *) & sp->slot[sp->header.stblindex];
+	nextindex = sp->header.nextindex;
+	for (nxt = off = 0; nxt < nextindex; ++off) {
+		if (off == skip)
+			/* check for fill factor with new entry size */
+			n = split->nslot;
+		else {
+			si = stbl[nxt];
+			switch (sp->header.flag & BT_TYPE) {
+			case BT_LEAF:
+				ldtentry = (struct ldtentry *) & sp->slot[si];
+				if (DO_INDEX(ip))
+					n = NDTLEAF(ldtentry->namlen);
+				else
+					n = NDTLEAF_LEGACY(ldtentry->
+							   namlen);
+				break;
+
+			case BT_INTERNAL:
+				idtentry = (struct idtentry *) & sp->slot[si];
+				n = NDTINTERNAL(idtentry->namlen);
+				break;
+
+			default:
+				break;
+			}
+
+			++nxt;	/* advance to next entry to move in sp */
+		}
+
+		left += n;
+		if (left >= half)
+			break;
+	}
+
+	/* <nxt> poins to the 1st entry to move */
+
+	/*
+	 *	move entries to right page
+	 *
+	 * dtMoveEntry() initializes rp and reserves entry for insertion
+	 *
+	 * split page moved out entries are linelocked;
+	 * new/right page moved in entries are linelocked;
+	 */
+	/* linelock header + stbl of new right page */
+	rlv = & rdtlck->lv[rdtlck->index];
+	rlv->offset = 0;
+	rlv->length = 5;
+	rdtlck->index++;
+
+	dtMoveEntry(sp, nxt, rp, &sdtlck, &rdtlck, DO_INDEX(ip));
+
+	sp->header.nextindex = nxt;
+
+	/*
+	 * finalize freelist of new right page
+	 */
+	fsi = rp->header.freelist;
+	f = &rp->slot[fsi];
+	for (fsi++; fsi < rp->header.maxslot; f++, fsi++)
+		f->next = fsi;
+	f->next = -1;
+
+	/*
+	 * Update directory index table for entries now in right page
+	 */
+	if ((rp->header.flag & BT_LEAF) && DO_INDEX(ip)) {
+		s64 lblock;
+
+		mp = NULL;
+		stbl = DT_GETSTBL(rp);
+		for (n = 0; n < rp->header.nextindex; n++) {
+			ldtentry = (struct ldtentry *) & rp->slot[stbl[n]];
+			modify_index(tid, ip, le32_to_cpu(ldtentry->index),
+				     rbn, n, &mp, &lblock);
+		}
+		if (mp)
+			release_metapage(mp);
+	}
+
+	/*
+	 * the skipped index was on the left page,
+	 */
+	if (skip <= off) {
+		/* insert the new entry in the split page */
+		dtInsertEntry(sp, skip, split->key, split->data, &sdtlck);
+
+		/* linelock stbl of split page */
+		if (sdtlck->index >= sdtlck->maxcnt)
+			sdtlck = (struct dt_lock *) txLinelock(sdtlck);
+		slv = & sdtlck->lv[sdtlck->index];
+		n = skip >> L2DTSLOTSIZE;
+		slv->offset = sp->header.stblindex + n;
+		slv->length =
+		    ((sp->header.nextindex - 1) >> L2DTSLOTSIZE) - n + 1;
+		sdtlck->index++;
+	}
+	/*
+	 * the skipped index was on the right page,
+	 */
+	else {
+		/* adjust the skip index to reflect the new position */
+		skip -= nxt;
+
+		/* insert the new entry in the right page */
+		dtInsertEntry(rp, skip, split->key, split->data, &rdtlck);
+	}
+
+      out:
+	*rmpp = rmp;
+	*rpxdp = *pxd;
+
+	return rc;
+}
+
+
+/*
+ *	dtExtendPage()
+ *
+ * function: extend 1st/only directory leaf page
+ *
+ * parameter:
+ *
+ * return: 0 - success;
+ *	   errno - failure;
+ *	return extended page pinned;
+ */
+static int dtExtendPage(tid_t tid,
+	     struct inode *ip, struct dtsplit * split, struct btstack * btstack)
+{
+	struct super_block *sb = ip->i_sb;
+	int rc;
+	struct metapage *smp, *pmp, *mp;
+	dtpage_t *sp, *pp;
+	struct pxdlist *pxdlist;
+	pxd_t *pxd, *tpxd;
+	int xlen, xsize;
+	int newstblindex, newstblsize;
+	int oldstblindex, oldstblsize;
+	int fsi, last;
+	struct dtslot *f;
+	struct btframe *parent;
+	int n;
+	struct dt_lock *dtlck;
+	s64 xaddr, txaddr;
+	struct tlock *tlck;
+	struct pxd_lock *pxdlock;
+	struct lv *lv;
+	uint type;
+	struct ldtentry *ldtentry;
+	u8 *stbl;
+
+	/* get page to extend */
+	smp = split->mp;
+	sp = DT_PAGE(ip, smp);
+
+	/* get parent/root page */
+	parent = BT_POP(btstack);
+	DT_GETPAGE(ip, parent->bn, pmp, PSIZE, pp, rc);
+	if (rc)
+		return (rc);
+
+	/*
+	 *	extend the extent
+	 */
+	pxdlist = split->pxdlist;
+	pxd = &pxdlist->pxd[pxdlist->npxd];
+	pxdlist->npxd++;
+
+	xaddr = addressPXD(pxd);
+	tpxd = &sp->header.self;
+	txaddr = addressPXD(tpxd);
+	/* in-place extension */
+	if (xaddr == txaddr) {
+		type = tlckEXTEND;
+	}
+	/* relocation */
+	else {
+		type = tlckNEW;
+
+		/* save moved extent descriptor for later free */
+		tlck = txMaplock(tid, ip, tlckDTREE | tlckRELOCATE);
+		pxdlock = (struct pxd_lock *) & tlck->lock;
+		pxdlock->flag = mlckFREEPXD;
+		pxdlock->pxd = sp->header.self;
+		pxdlock->index = 1;
+
+		/*
+		 * Update directory index table to reflect new page address
+		 */
+		if (DO_INDEX(ip)) {
+			s64 lblock;
+
+			mp = NULL;
+			stbl = DT_GETSTBL(sp);
+			for (n = 0; n < sp->header.nextindex; n++) {
+				ldtentry =
+				    (struct ldtentry *) & sp->slot[stbl[n]];
+				modify_index(tid, ip,
+					     le32_to_cpu(ldtentry->index),
+					     xaddr, n, &mp, &lblock);
+			}
+			if (mp)
+				release_metapage(mp);
+		}
+	}
+
+	/*
+	 *	extend the page
+	 */
+	sp->header.self = *pxd;
+
+	jfs_info("dtExtendPage: ip:0x%p smp:0x%p sp:0x%p", ip, smp, sp);
+
+	BT_MARK_DIRTY(smp, ip);
+	/*
+	 * acquire a transaction lock on the extended/leaf page
+	 */
+	tlck = txLock(tid, ip, smp, tlckDTREE | type);
+	dtlck = (struct dt_lock *) & tlck->lock;
+	lv = & dtlck->lv[0];
+
+	/* update buffer extent descriptor of extended page */
+	xlen = lengthPXD(pxd);
+	xsize = xlen << JFS_SBI(sb)->l2bsize;
+
+	/*
+	 * copy old stbl to new stbl at start of extended area
+	 */
+	oldstblindex = sp->header.stblindex;
+	oldstblsize = (sp->header.maxslot + 31) >> L2DTSLOTSIZE;
+	newstblindex = sp->header.maxslot;
+	n = xsize >> L2DTSLOTSIZE;
+	newstblsize = (n + 31) >> L2DTSLOTSIZE;
+	memcpy(&sp->slot[newstblindex], &sp->slot[oldstblindex],
+	       sp->header.nextindex);
+
+	/*
+	 * in-line extension: linelock old area of extended page
+	 */
+	if (type == tlckEXTEND) {
+		/* linelock header */
+		lv->offset = 0;
+		lv->length = 1;
+		dtlck->index++;
+		lv++;
+
+		/* linelock new stbl of extended page */
+		lv->offset = newstblindex;
+		lv->length = newstblsize;
+	}
+	/*
+	 * relocation: linelock whole relocated area
+	 */
+	else {
+		lv->offset = 0;
+		lv->length = sp->header.maxslot + newstblsize;
+	}
+
+	dtlck->index++;
+
+	sp->header.maxslot = n;
+	sp->header.stblindex = newstblindex;
+	/* sp->header.nextindex remains the same */
+
+	/*
+	 * add old stbl region at head of freelist
+	 */
+	fsi = oldstblindex;
+	f = &sp->slot[fsi];
+	last = sp->header.freelist;
+	for (n = 0; n < oldstblsize; n++, fsi++, f++) {
+		f->next = last;
+		last = fsi;
+	}
+	sp->header.freelist = last;
+	sp->header.freecnt += oldstblsize;
+
+	/*
+	 * append free region of newly extended area at tail of freelist
+	 */
+	/* init free region of newly extended area */
+	fsi = n = newstblindex + newstblsize;
+	f = &sp->slot[fsi];
+	for (fsi++; fsi < sp->header.maxslot; f++, fsi++)
+		f->next = fsi;
+	f->next = -1;
+
+	/* append new free region at tail of old freelist */
+	fsi = sp->header.freelist;
+	if (fsi == -1)
+		sp->header.freelist = n;
+	else {
+		do {
+			f = &sp->slot[fsi];
+			fsi = f->next;
+		} while (fsi != -1);
+
+		f->next = n;
+	}
+
+	sp->header.freecnt += sp->header.maxslot - n;
+
+	/*
+	 * insert the new entry
+	 */
+	dtInsertEntry(sp, split->index, split->key, split->data, &dtlck);
+
+	BT_MARK_DIRTY(pmp, ip);
+	/*
+	 * linelock any freeslots residing in old extent
+	 */
+	if (type == tlckEXTEND) {
+		n = sp->header.maxslot >> 2;
+		if (sp->header.freelist < n)
+			dtLinelockFreelist(sp, n, &dtlck);
+	}
+
+	/*
+	 *	update parent entry on the parent/root page
+	 */
+	/*
+	 * acquire a transaction lock on the parent/root page
+	 */
+	tlck = txLock(tid, ip, pmp, tlckDTREE | tlckENTRY);
+	dtlck = (struct dt_lock *) & tlck->lock;
+	lv = & dtlck->lv[dtlck->index];
+
+	/* linelock parent entry - 1st slot */
+	lv->offset = 1;
+	lv->length = 1;
+	dtlck->index++;
+
+	/* update the parent pxd for page extension */
+	tpxd = (pxd_t *) & pp->slot[1];
+	*tpxd = *pxd;
+
+	DT_PUTPAGE(pmp);
+	return 0;
+}
+
+
+/*
+ *	dtSplitRoot()
+ *
+ * function:
+ *	split the full root page into
+ *	original/root/split page and new right page
+ *	i.e., root remains fixed in tree anchor (inode) and
+ *	the root is copied to a single new right child page
+ *	since root page << non-root page, and
+ *	the split root page contains a single entry for the
+ *	new right child page.
+ *
+ * parameter:
+ *
+ * return: 0 - success;
+ *	   errno - failure;
+ *	return new page pinned;
+ */
+static int dtSplitRoot(tid_t tid,
+	    struct inode *ip, struct dtsplit * split, struct metapage ** rmpp)
+{
+	struct super_block *sb = ip->i_sb;
+	struct metapage *smp;
+	dtroot_t *sp;
+	struct metapage *rmp;
+	dtpage_t *rp;
+	s64 rbn;
+	int xlen;
+	int xsize;
+	struct dtslot *f;
+	s8 *stbl;
+	int fsi, stblsize, n;
+	struct idtentry *s;
+	pxd_t *ppxd;
+	struct pxdlist *pxdlist;
+	pxd_t *pxd;
+	struct dt_lock *dtlck;
+	struct tlock *tlck;
+	struct lv *lv;
+	int rc;
+
+	/* get split root page */
+	smp = split->mp;
+	sp = &JFS_IP(ip)->i_dtroot;
+
+	/*
+	 *	allocate/initialize a single (right) child page
+	 *
+	 * N.B. at first split, a one (or two) block to fit new entry
+	 * is allocated; at subsequent split, a full page is allocated;
+	 */
+	pxdlist = split->pxdlist;
+	pxd = &pxdlist->pxd[pxdlist->npxd];
+	pxdlist->npxd++;
+	rbn = addressPXD(pxd);
+	xlen = lengthPXD(pxd);
+	xsize = xlen << JFS_SBI(sb)->l2bsize;
+	rmp = get_metapage(ip, rbn, xsize, 1);
+	if (!rmp)
+		return -EIO;
+
+	rp = rmp->data;
+
+	/* Allocate blocks to quota. */
+	rc = dquot_alloc_block(ip, lengthPXD(pxd));
+	if (rc) {
+		release_metapage(rmp);
+		return rc;
+	}
+
+	BT_MARK_DIRTY(rmp, ip);
+	/*
+	 * acquire a transaction lock on the new right page
+	 */
+	tlck = txLock(tid, ip, rmp, tlckDTREE | tlckNEW);
+	dtlck = (struct dt_lock *) & tlck->lock;
+
+	rp->header.flag =
+	    (sp->header.flag & BT_LEAF) ? BT_LEAF : BT_INTERNAL;
+	rp->header.self = *pxd;
+
+	/* initialize sibling pointers */
+	rp->header.next = 0;
+	rp->header.prev = 0;
+
+	/*
+	 *	move in-line root page into new right page extent
+	 */
+	/* linelock header + copied entries + new stbl (1st slot) in new page */
+	ASSERT(dtlck->index == 0);
+	lv = & dtlck->lv[0];
+	lv->offset = 0;
+	lv->length = 10;	/* 1 + 8 + 1 */
+	dtlck->index++;
+
+	n = xsize >> L2DTSLOTSIZE;
+	rp->header.maxslot = n;
+	stblsize = (n + 31) >> L2DTSLOTSIZE;
+
+	/* copy old stbl to new stbl at start of extended area */
+	rp->header.stblindex = DTROOTMAXSLOT;
+	stbl = (s8 *) & rp->slot[DTROOTMAXSLOT];
+	memcpy(stbl, sp->header.stbl, sp->header.nextindex);
+	rp->header.nextindex = sp->header.nextindex;
+
+	/* copy old data area to start of new data area */
+	memcpy(&rp->slot[1], &sp->slot[1], IDATASIZE);
+
+	/*
+	 * append free region of newly extended area at tail of freelist
+	 */
+	/* init free region of newly extended area */
+	fsi = n = DTROOTMAXSLOT + stblsize;
+	f = &rp->slot[fsi];
+	for (fsi++; fsi < rp->header.maxslot; f++, fsi++)
+		f->next = fsi;
+	f->next = -1;
+
+	/* append new free region at tail of old freelist */
+	fsi = sp->header.freelist;
+	if (fsi == -1)
+		rp->header.freelist = n;
+	else {
+		rp->header.freelist = fsi;
+
+		do {
+			f = &rp->slot[fsi];
+			fsi = f->next;
+		} while (fsi != -1);
+
+		f->next = n;
+	}
+
+	rp->header.freecnt = sp->header.freecnt + rp->header.maxslot - n;
+
+	/*
+	 * Update directory index table for entries now in right page
+	 */
+	if ((rp->header.flag & BT_LEAF) && DO_INDEX(ip)) {
+		s64 lblock;
+		struct metapage *mp = NULL;
+		struct ldtentry *ldtentry;
+
+		stbl = DT_GETSTBL(rp);
+		for (n = 0; n < rp->header.nextindex; n++) {
+			ldtentry = (struct ldtentry *) & rp->slot[stbl[n]];
+			modify_index(tid, ip, le32_to_cpu(ldtentry->index),
+				     rbn, n, &mp, &lblock);
+		}
+		if (mp)
+			release_metapage(mp);
+	}
+	/*
+	 * insert the new entry into the new right/child page
+	 * (skip index in the new right page will not change)
+	 */
+	dtInsertEntry(rp, split->index, split->key, split->data, &dtlck);
+
+	/*
+	 *	reset parent/root page
+	 *
+	 * set the 1st entry offset to 0, which force the left-most key
+	 * at any level of the tree to be less than any search key.
+	 *
+	 * The btree comparison code guarantees that the left-most key on any
+	 * level of the tree is never used, so it doesn't need to be filled in.
+	 */
+	BT_MARK_DIRTY(smp, ip);
+	/*
+	 * acquire a transaction lock on the root page (in-memory inode)
+	 */
+	tlck = txLock(tid, ip, smp, tlckDTREE | tlckNEW | tlckBTROOT);
+	dtlck = (struct dt_lock *) & tlck->lock;
+
+	/* linelock root */
+	ASSERT(dtlck->index == 0);
+	lv = & dtlck->lv[0];
+	lv->offset = 0;
+	lv->length = DTROOTMAXSLOT;
+	dtlck->index++;
+
+	/* update page header of root */
+	if (sp->header.flag & BT_LEAF) {
+		sp->header.flag &= ~BT_LEAF;
+		sp->header.flag |= BT_INTERNAL;
+	}
+
+	/* init the first entry */
+	s = (struct idtentry *) & sp->slot[DTENTRYSTART];
+	ppxd = (pxd_t *) s;
+	*ppxd = *pxd;
+	s->next = -1;
+	s->namlen = 0;
+
+	stbl = sp->header.stbl;
+	stbl[0] = DTENTRYSTART;
+	sp->header.nextindex = 1;
+
+	/* init freelist */
+	fsi = DTENTRYSTART + 1;
+	f = &sp->slot[fsi];
+
+	/* init free region of remaining area */
+	for (fsi++; fsi < DTROOTMAXSLOT; f++, fsi++)
+		f->next = fsi;
+	f->next = -1;
+
+	sp->header.freelist = DTENTRYSTART + 1;
+	sp->header.freecnt = DTROOTMAXSLOT - (DTENTRYSTART + 1);
+
+	*rmpp = rmp;
+
+	return 0;
+}
+
+
+/*
+ *	dtDelete()
+ *
+ * function: delete the entry(s) referenced by a key.
+ *
+ * parameter:
+ *
+ * return:
+ */
+int dtDelete(tid_t tid,
+	 struct inode *ip, struct component_name * key, ino_t * ino, int flag)
+{
+	int rc = 0;
+	s64 bn;
+	struct metapage *mp, *imp;
+	dtpage_t *p;
+	int index;
+	struct btstack btstack;
+	struct dt_lock *dtlck;
+	struct tlock *tlck;
+	struct lv *lv;
+	int i;
+	struct ldtentry *ldtentry;
+	u8 *stbl;
+	u32 table_index, next_index;
+	struct metapage *nmp;
+	dtpage_t *np;
+
+	/*
+	 *	search for the entry to delete:
+	 *
+	 * dtSearch() returns (leaf page pinned, index at which to delete).
+	 */
+	if ((rc = dtSearch(ip, key, ino, &btstack, flag)))
+		return rc;
+
+	/* retrieve search result */
+	DT_GETSEARCH(ip, btstack.top, bn, mp, p, index);
+
+	/*
+	 * We need to find put the index of the next entry into the
+	 * directory index table in order to resume a readdir from this
+	 * entry.
+	 */
+	if (DO_INDEX(ip)) {
+		stbl = DT_GETSTBL(p);
+		ldtentry = (struct ldtentry *) & p->slot[stbl[index]];
+		table_index = le32_to_cpu(ldtentry->index);
+		if (index == (p->header.nextindex - 1)) {
+			/*
+			 * Last entry in this leaf page
+			 */
+			if ((p->header.flag & BT_ROOT)
+			    || (p->header.next == 0))
+				next_index = -1;
+			else {
+				/* Read next leaf page */
+				DT_GETPAGE(ip, le64_to_cpu(p->header.next),
+					   nmp, PSIZE, np, rc);
+				if (rc)
+					next_index = -1;
+				else {
+					stbl = DT_GETSTBL(np);
+					ldtentry =
+					    (struct ldtentry *) & np->
+					    slot[stbl[0]];
+					next_index =
+					    le32_to_cpu(ldtentry->index);
+					DT_PUTPAGE(nmp);
+				}
+			}
+		} else {
+			ldtentry =
+			    (struct ldtentry *) & p->slot[stbl[index + 1]];
+			next_index = le32_to_cpu(ldtentry->index);
+		}
+		free_index(tid, ip, table_index, next_index);
+	}
+	/*
+	 * the leaf page becomes empty, delete the page
+	 */
+	if (p->header.nextindex == 1) {
+		/* delete empty page */
+		rc = dtDeleteUp(tid, ip, mp, p, &btstack);
+	}
+	/*
+	 * the leaf page has other entries remaining:
+	 *
+	 * delete the entry from the leaf page.
+	 */
+	else {
+		BT_MARK_DIRTY(mp, ip);
+		/*
+		 * acquire a transaction lock on the leaf page
+		 */
+		tlck = txLock(tid, ip, mp, tlckDTREE | tlckENTRY);
+		dtlck = (struct dt_lock *) & tlck->lock;
+
+		/*
+		 * Do not assume that dtlck->index will be zero.  During a
+		 * rename within a directory, this transaction may have
+		 * modified this page already when adding the new entry.
+		 */
+
+		/* linelock header */
+		if (dtlck->index >= dtlck->maxcnt)
+			dtlck = (struct dt_lock *) txLinelock(dtlck);
+		lv = & dtlck->lv[dtlck->index];
+		lv->offset = 0;
+		lv->length = 1;
+		dtlck->index++;
+
+		/* linelock stbl of non-root leaf page */
+		if (!(p->header.flag & BT_ROOT)) {
+			if (dtlck->index >= dtlck->maxcnt)
+				dtlck = (struct dt_lock *) txLinelock(dtlck);
+			lv = & dtlck->lv[dtlck->index];
+			i = index >> L2DTSLOTSIZE;
+			lv->offset = p->header.stblindex + i;
+			lv->length =
+			    ((p->header.nextindex - 1) >> L2DTSLOTSIZE) -
+			    i + 1;
+			dtlck->index++;
+		}
+
+		/* free the leaf entry */
+		dtDeleteEntry(p, index, &dtlck);
+
+		/*
+		 * Update directory index table for entries moved in stbl
+		 */
+		if (DO_INDEX(ip) && index < p->header.nextindex) {
+			s64 lblock;
+
+			imp = NULL;
+			stbl = DT_GETSTBL(p);
+			for (i = index; i < p->header.nextindex; i++) {
+				ldtentry =
+				    (struct ldtentry *) & p->slot[stbl[i]];
+				modify_index(tid, ip,
+					     le32_to_cpu(ldtentry->index),
+					     bn, i, &imp, &lblock);
+			}
+			if (imp)
+				release_metapage(imp);
+		}
+
+		DT_PUTPAGE(mp);
+	}
+
+	return rc;
+}
+
+
+/*
+ *	dtDeleteUp()
+ *
+ * function:
+ *	free empty pages as propagating deletion up the tree
+ *
+ * parameter:
+ *
+ * return:
+ */
+static int dtDeleteUp(tid_t tid, struct inode *ip,
+	   struct metapage * fmp, dtpage_t * fp, struct btstack * btstack)
+{
+	int rc = 0;
+	struct metapage *mp;
+	dtpage_t *p;
+	int index, nextindex;
+	int xlen;
+	struct btframe *parent;
+	struct dt_lock *dtlck;
+	struct tlock *tlck;
+	struct lv *lv;
+	struct pxd_lock *pxdlock;
+	int i;
+
+	/*
+	 *	keep the root leaf page which has become empty
+	 */
+	if (BT_IS_ROOT(fmp)) {
+		/*
+		 * reset the root
+		 *
+		 * dtInitRoot() acquires txlock on the root
+		 */
+		dtInitRoot(tid, ip, PARENT(ip));
+
+		DT_PUTPAGE(fmp);
+
+		return 0;
+	}
+
+	/*
+	 *	free the non-root leaf page
+	 */
+	/*
+	 * acquire a transaction lock on the page
+	 *
+	 * write FREEXTENT|NOREDOPAGE log record
+	 * N.B. linelock is overlaid as freed extent descriptor, and
+	 * the buffer page is freed;
+	 */
+	tlck = txMaplock(tid, ip, tlckDTREE | tlckFREE);
+	pxdlock = (struct pxd_lock *) & tlck->lock;
+	pxdlock->flag = mlckFREEPXD;
+	pxdlock->pxd = fp->header.self;
+	pxdlock->index = 1;
+
+	/* update sibling pointers */
+	if ((rc = dtRelink(tid, ip, fp))) {
+		BT_PUTPAGE(fmp);
+		return rc;
+	}
+
+	xlen = lengthPXD(&fp->header.self);
+
+	/* Free quota allocation. */
+	dquot_free_block(ip, xlen);
+
+	/* free/invalidate its buffer page */
+	discard_metapage(fmp);
+
+	/*
+	 *	propagate page deletion up the directory tree
+	 *
+	 * If the delete from the parent page makes it empty,
+	 * continue all the way up the tree.
+	 * stop if the root page is reached (which is never deleted) or
+	 * if the entry deletion does not empty the page.
+	 */
+	while ((parent = BT_POP(btstack)) != NULL) {
+		/* pin the parent page <sp> */
+		DT_GETPAGE(ip, parent->bn, mp, PSIZE, p, rc);
+		if (rc)
+			return rc;
+
+		/*
+		 * free the extent of the child page deleted
+		 */
+		index = parent->index;
+
+		/*
+		 * delete the entry for the child page from parent
+		 */
+		nextindex = p->header.nextindex;
+
+		/*
+		 * the parent has the single entry being deleted:
+		 *
+		 * free the parent page which has become empty.
+		 */
+		if (nextindex == 1) {
+			/*
+			 * keep the root internal page which has become empty
+			 */
+			if (p->header.flag & BT_ROOT) {
+				/*
+				 * reset the root
+				 *
+				 * dtInitRoot() acquires txlock on the root
+				 */
+				dtInitRoot(tid, ip, PARENT(ip));
+
+				DT_PUTPAGE(mp);
+
+				return 0;
+			}
+			/*
+			 * free the parent page
+			 */
+			else {
+				/*
+				 * acquire a transaction lock on the page
+				 *
+				 * write FREEXTENT|NOREDOPAGE log record
+				 */
+				tlck =
+				    txMaplock(tid, ip,
+					      tlckDTREE | tlckFREE);
+				pxdlock = (struct pxd_lock *) & tlck->lock;
+				pxdlock->flag = mlckFREEPXD;
+				pxdlock->pxd = p->header.self;
+				pxdlock->index = 1;
+
+				/* update sibling pointers */
+				if ((rc = dtRelink(tid, ip, p))) {
+					DT_PUTPAGE(mp);
+					return rc;
+				}
+
+				xlen = lengthPXD(&p->header.self);
+
+				/* Free quota allocation */
+				dquot_free_block(ip, xlen);
+
+				/* free/invalidate its buffer page */
+				discard_metapage(mp);
+
+				/* propagate up */
+				continue;
+			}
+		}
+
+		/*
+		 * the parent has other entries remaining:
+		 *
+		 * delete the router entry from the parent page.
+		 */
+		BT_MARK_DIRTY(mp, ip);
+		/*
+		 * acquire a transaction lock on the page
+		 *
+		 * action: router entry deletion
+		 */
+		tlck = txLock(tid, ip, mp, tlckDTREE | tlckENTRY);
+		dtlck = (struct dt_lock *) & tlck->lock;
+
+		/* linelock header */
+		if (dtlck->index >= dtlck->maxcnt)
+			dtlck = (struct dt_lock *) txLinelock(dtlck);
+		lv = & dtlck->lv[dtlck->index];
+		lv->offset = 0;
+		lv->length = 1;
+		dtlck->index++;
+
+		/* linelock stbl of non-root leaf page */
+		if (!(p->header.flag & BT_ROOT)) {
+			if (dtlck->index < dtlck->maxcnt)
+				lv++;
+			else {
+				dtlck = (struct dt_lock *) txLinelock(dtlck);
+				lv = & dtlck->lv[0];
+			}
+			i = index >> L2DTSLOTSIZE;
+			lv->offset = p->header.stblindex + i;
+			lv->length =
+			    ((p->header.nextindex - 1) >> L2DTSLOTSIZE) -
+			    i + 1;
+			dtlck->index++;
+		}
+
+		/* free the router entry */
+		dtDeleteEntry(p, index, &dtlck);
+
+		/* reset key of new leftmost entry of level (for consistency) */
+		if (index == 0 &&
+		    ((p->header.flag & BT_ROOT) || p->header.prev == 0))
+			dtTruncateEntry(p, 0, &dtlck);
+
+		/* unpin the parent page */
+		DT_PUTPAGE(mp);
+
+		/* exit propagation up */
+		break;
+	}
+
+	if (!DO_INDEX(ip))
+		ip->i_size -= PSIZE;
+
+	return 0;
+}
+
+/*
+ *	dtRelink()
+ *
+ * function:
+ *	link around a freed page.
+ *
+ * parameter:
+ *	fp:	page to be freed
+ *
+ * return:
+ */
+static int dtRelink(tid_t tid, struct inode *ip, dtpage_t * p)
+{
+	int rc;
+	struct metapage *mp;
+	s64 nextbn, prevbn;
+	struct tlock *tlck;
+	struct dt_lock *dtlck;
+	struct lv *lv;
+
+	nextbn = le64_to_cpu(p->header.next);
+	prevbn = le64_to_cpu(p->header.prev);
+
+	/* update prev pointer of the next page */
+	if (nextbn != 0) {
+		DT_GETPAGE(ip, nextbn, mp, PSIZE, p, rc);
+		if (rc)
+			return rc;
+
+		BT_MARK_DIRTY(mp, ip);
+		/*
+		 * acquire a transaction lock on the next page
+		 *
+		 * action: update prev pointer;
+		 */
+		tlck = txLock(tid, ip, mp, tlckDTREE | tlckRELINK);
+		jfs_info("dtRelink nextbn: tlck = 0x%p, ip = 0x%p, mp=0x%p",
+			tlck, ip, mp);
+		dtlck = (struct dt_lock *) & tlck->lock;
+
+		/* linelock header */
+		if (dtlck->index >= dtlck->maxcnt)
+			dtlck = (struct dt_lock *) txLinelock(dtlck);
+		lv = & dtlck->lv[dtlck->index];
+		lv->offset = 0;
+		lv->length = 1;
+		dtlck->index++;
+
+		p->header.prev = cpu_to_le64(prevbn);
+		DT_PUTPAGE(mp);
+	}
+
+	/* update next pointer of the previous page */
+	if (prevbn != 0) {
+		DT_GETPAGE(ip, prevbn, mp, PSIZE, p, rc);
+		if (rc)
+			return rc;
+
+		BT_MARK_DIRTY(mp, ip);
+		/*
+		 * acquire a transaction lock on the prev page
+		 *
+		 * action: update next pointer;
+		 */
+		tlck = txLock(tid, ip, mp, tlckDTREE | tlckRELINK);
+		jfs_info("dtRelink prevbn: tlck = 0x%p, ip = 0x%p, mp=0x%p",
+			tlck, ip, mp);
+		dtlck = (struct dt_lock *) & tlck->lock;
+
+		/* linelock header */
+		if (dtlck->index >= dtlck->maxcnt)
+			dtlck = (struct dt_lock *) txLinelock(dtlck);
+		lv = & dtlck->lv[dtlck->index];
+		lv->offset = 0;
+		lv->length = 1;
+		dtlck->index++;
+
+		p->header.next = cpu_to_le64(nextbn);
+		DT_PUTPAGE(mp);
+	}
+
+	return 0;
+}
+
+
+/*
+ *	dtInitRoot()
+ *
+ * initialize directory root (inline in inode)
+ */
+void dtInitRoot(tid_t tid, struct inode *ip, u32 idotdot)
+{
+	struct jfs_inode_info *jfs_ip = JFS_IP(ip);
+	dtroot_t *p;
+	int fsi;
+	struct dtslot *f;
+	struct tlock *tlck;
+	struct dt_lock *dtlck;
+	struct lv *lv;
+	u16 xflag_save;
+
+	/*
+	 * If this was previously an non-empty directory, we need to remove
+	 * the old directory table.
+	 */
+	if (DO_INDEX(ip)) {
+		if (!jfs_dirtable_inline(ip)) {
+			struct tblock *tblk = tid_to_tblock(tid);
+			/*
+			 * We're playing games with the tid's xflag.  If
+			 * we're removing a regular file, the file's xtree
+			 * is committed with COMMIT_PMAP, but we always
+			 * commit the directories xtree with COMMIT_PWMAP.
+			 */
+			xflag_save = tblk->xflag;
+			tblk->xflag = 0;
+			/*
+			 * xtTruncate isn't guaranteed to fully truncate
+			 * the xtree.  The caller needs to check i_size
+			 * after committing the transaction to see if
+			 * additional truncation is needed.  The
+			 * COMMIT_Stale flag tells caller that we
+			 * initiated the truncation.
+			 */
+			xtTruncate(tid, ip, 0, COMMIT_PWMAP);
+			set_cflag(COMMIT_Stale, ip);
+
+			tblk->xflag = xflag_save;
+		} else
+			ip->i_size = 1;
+
+		jfs_ip->next_index = 2;
+	} else
+		ip->i_size = IDATASIZE;
+
+	/*
+	 * acquire a transaction lock on the root
+	 *
+	 * action: directory initialization;
+	 */
+	tlck = txLock(tid, ip, (struct metapage *) & jfs_ip->bxflag,
+		      tlckDTREE | tlckENTRY | tlckBTROOT);
+	dtlck = (struct dt_lock *) & tlck->lock;
+
+	/* linelock root */
+	ASSERT(dtlck->index == 0);
+	lv = & dtlck->lv[0];
+	lv->offset = 0;
+	lv->length = DTROOTMAXSLOT;
+	dtlck->index++;
+
+	p = &jfs_ip->i_dtroot;
+
+	p->header.flag = DXD_INDEX | BT_ROOT | BT_LEAF;
+
+	p->header.nextindex = 0;
+
+	/* init freelist */
+	fsi = 1;
+	f = &p->slot[fsi];
+
+	/* init data area of root */
+	for (fsi++; fsi < DTROOTMAXSLOT; f++, fsi++)
+		f->next = fsi;
+	f->next = -1;
+
+	p->header.freelist = 1;
+	p->header.freecnt = 8;
+
+	/* init '..' entry */
+	p->header.idotdot = cpu_to_le32(idotdot);
+
+	return;
+}
+
+/*
+ *	add_missing_indices()
+ *
+ * function: Fix dtree page in which one or more entries has an invalid index.
+ *	     fsck.jfs should really fix this, but it currently does not.
+ *	     Called from jfs_readdir when bad index is detected.
+ */
+static void add_missing_indices(struct inode *inode, s64 bn)
+{
+	struct ldtentry *d;
+	struct dt_lock *dtlck;
+	int i;
+	uint index;
+	struct lv *lv;
+	struct metapage *mp;
+	dtpage_t *p;
+	int rc;
+	s8 *stbl;
+	tid_t tid;
+	struct tlock *tlck;
+
+	tid = txBegin(inode->i_sb, 0);
+
+	DT_GETPAGE(inode, bn, mp, PSIZE, p, rc);
+
+	if (rc) {
+		printk(KERN_ERR "DT_GETPAGE failed!\n");
+		goto end;
+	}
+	BT_MARK_DIRTY(mp, inode);
+
+	ASSERT(p->header.flag & BT_LEAF);
+
+	tlck = txLock(tid, inode, mp, tlckDTREE | tlckENTRY);
+	if (BT_IS_ROOT(mp))
+		tlck->type |= tlckBTROOT;
+
+	dtlck = (struct dt_lock *) &tlck->lock;
+
+	stbl = DT_GETSTBL(p);
+	for (i = 0; i < p->header.nextindex; i++) {
+		d = (struct ldtentry *) &p->slot[stbl[i]];
+		index = le32_to_cpu(d->index);
+		if ((index < 2) || (index >= JFS_IP(inode)->next_index)) {
+			d->index = cpu_to_le32(add_index(tid, inode, bn, i));
+			if (dtlck->index >= dtlck->maxcnt)
+				dtlck = (struct dt_lock *) txLinelock(dtlck);
+			lv = &dtlck->lv[dtlck->index];
+			lv->offset = stbl[i];
+			lv->length = 1;
+			dtlck->index++;
+		}
+	}
+
+	DT_PUTPAGE(mp);
+	(void) txCommit(tid, 1, &inode, 0);
+end:
+	txEnd(tid);
+}
+
+/*
+ * Buffer to hold directory entry info while traversing a dtree page
+ * before being fed to the filldir function
+ */
+struct jfs_dirent {
+	loff_t position;
+	int ino;
+	u16 name_len;
+	char name[];
+};
+
+/*
+ * function to determine next variable-sized jfs_dirent in buffer
+ */
+static inline struct jfs_dirent *next_jfs_dirent(struct jfs_dirent *dirent)
+{
+	return (struct jfs_dirent *)
+		((char *)dirent +
+		 ((sizeof (struct jfs_dirent) + dirent->name_len + 1 +
+		   sizeof (loff_t) - 1) &
+		  ~(sizeof (loff_t) - 1)));
+}
+
+/*
+ *	jfs_readdir()
+ *
+ * function: read directory entries sequentially
+ *	from the specified entry offset
+ *
+ * parameter:
+ *
+ * return: offset = (pn, index) of start entry
+ *	of next jfs_readdir()/dtRead()
+ */
+int jfs_readdir(struct file *file, struct dir_context *ctx)
+{
+	struct inode *ip = file_inode(file);
+	struct nls_table *codepage = JFS_SBI(ip->i_sb)->nls_tab;
+	int rc = 0;
+	loff_t dtpos;	/* legacy OS/2 style position */
+	struct dtoffset {
+		s16 pn;
+		s16 index;
+		s32 unused;
+	} *dtoffset = (struct dtoffset *) &dtpos;
+	s64 bn;
+	struct metapage *mp;
+	dtpage_t *p;
+	int index;
+	s8 *stbl;
+	struct btstack btstack;
+	int i, next;
+	struct ldtentry *d;
+	struct dtslot *t;
+	int d_namleft, len, outlen;
+	unsigned long dirent_buf;
+	char *name_ptr;
+	u32 dir_index;
+	int do_index = 0;
+	uint loop_count = 0;
+	struct jfs_dirent *jfs_dirent;
+	int jfs_dirents;
+	int overflow, fix_page, page_fixed = 0;
+	static int unique_pos = 2;	/* If we can't fix broken index */
+
+	if (ctx->pos == DIREND)
+		return 0;
+
+	if (DO_INDEX(ip)) {
+		/*
+		 * persistent index is stored in directory entries.
+		 * Special cases:	 0 = .
+		 *			 1 = ..
+		 *			-1 = End of directory
+		 */
+		do_index = 1;
+
+		dir_index = (u32) ctx->pos;
+
+		/*
+		 * NFSv4 reserves cookies 1 and 2 for . and .. so the value
+		 * we return to the vfs is one greater than the one we use
+		 * internally.
+		 */
+		if (dir_index)
+			dir_index--;
+
+		if (dir_index > 1) {
+			struct dir_table_slot dirtab_slot;
+
+			if (dtEmpty(ip) ||
+			    (dir_index >= JFS_IP(ip)->next_index)) {
+				/* Stale position.  Directory has shrunk */
+				ctx->pos = DIREND;
+				return 0;
+			}
+		      repeat:
+			rc = read_index(ip, dir_index, &dirtab_slot);
+			if (rc) {
+				ctx->pos = DIREND;
+				return rc;
+			}
+			if (dirtab_slot.flag == DIR_INDEX_FREE) {
+				if (loop_count++ > JFS_IP(ip)->next_index) {
+					jfs_err("jfs_readdir detected infinite loop!");
+					ctx->pos = DIREND;
+					return 0;
+				}
+				dir_index = le32_to_cpu(dirtab_slot.addr2);
+				if (dir_index == -1) {
+					ctx->pos = DIREND;
+					return 0;
+				}
+				goto repeat;
+			}
+			bn = addressDTS(&dirtab_slot);
+			index = dirtab_slot.slot;
+			DT_GETPAGE(ip, bn, mp, PSIZE, p, rc);
+			if (rc) {
+				ctx->pos = DIREND;
+				return 0;
+			}
+			if (p->header.flag & BT_INTERNAL) {
+				jfs_err("jfs_readdir: bad index table");
+				DT_PUTPAGE(mp);
+				ctx->pos = DIREND;
+				return 0;
+			}
+		} else {
+			if (dir_index == 0) {
+				/*
+				 * self "."
+				 */
+				ctx->pos = 1;
+				if (!dir_emit(ctx, ".", 1, ip->i_ino, DT_DIR))
+					return 0;
+			}
+			/*
+			 * parent ".."
+			 */
+			ctx->pos = 2;
+			if (!dir_emit(ctx, "..", 2, PARENT(ip), DT_DIR))
+				return 0;
+
+			/*
+			 * Find first entry of left-most leaf
+			 */
+			if (dtEmpty(ip)) {
+				ctx->pos = DIREND;
+				return 0;
+			}
+
+			if ((rc = dtReadFirst(ip, &btstack)))
+				return rc;
+
+			DT_GETSEARCH(ip, btstack.top, bn, mp, p, index);
+		}
+	} else {
+		/*
+		 * Legacy filesystem - OS/2 & Linux JFS < 0.3.6
+		 *
+		 * pn = 0; index = 1:	First entry "."
+		 * pn = 0; index = 2:	Second entry ".."
+		 * pn > 0:		Real entries, pn=1 -> leftmost page
+		 * pn = index = -1:	No more entries
+		 */
+		dtpos = ctx->pos;
+		if (dtpos < 2) {
+			/* build "." entry */
+			ctx->pos = 1;
+			if (!dir_emit(ctx, ".", 1, ip->i_ino, DT_DIR))
+				return 0;
+			dtoffset->index = 2;
+			ctx->pos = dtpos;
+		}
+
+		if (dtoffset->pn == 0) {
+			if (dtoffset->index == 2) {
+				/* build ".." entry */
+				if (!dir_emit(ctx, "..", 2, PARENT(ip), DT_DIR))
+					return 0;
+			} else {
+				jfs_err("jfs_readdir called with invalid offset!");
+			}
+			dtoffset->pn = 1;
+			dtoffset->index = 0;
+			ctx->pos = dtpos;
+		}
+
+		if (dtEmpty(ip)) {
+			ctx->pos = DIREND;
+			return 0;
+		}
+
+		if ((rc = dtReadNext(ip, &ctx->pos, &btstack))) {
+			jfs_err("jfs_readdir: unexpected rc = %d from dtReadNext",
+				rc);
+			ctx->pos = DIREND;
+			return 0;
+		}
+		/* get start leaf page and index */
+		DT_GETSEARCH(ip, btstack.top, bn, mp, p, index);
+
+		/* offset beyond directory eof ? */
+		if (bn < 0) {
+			ctx->pos = DIREND;
+			return 0;
+		}
+	}
+
+	dirent_buf = __get_free_page(GFP_KERNEL);
+	if (dirent_buf == 0) {
+		DT_PUTPAGE(mp);
+		jfs_warn("jfs_readdir: __get_free_page failed!");
+		ctx->pos = DIREND;
+		return -ENOMEM;
+	}
+
+	while (1) {
+		jfs_dirent = (struct jfs_dirent *) dirent_buf;
+		jfs_dirents = 0;
+		overflow = fix_page = 0;
+
+		stbl = DT_GETSTBL(p);
+
+		for (i = index; i < p->header.nextindex; i++) {
+			d = (struct ldtentry *) & p->slot[stbl[i]];
+
+			if (((long) jfs_dirent + d->namlen + 1) >
+			    (dirent_buf + PAGE_SIZE)) {
+				/* DBCS codepages could overrun dirent_buf */
+				index = i;
+				overflow = 1;
+				break;
+			}
+
+			d_namleft = d->namlen;
+			name_ptr = jfs_dirent->name;
+			jfs_dirent->ino = le32_to_cpu(d->inumber);
+
+			if (do_index) {
+				len = min(d_namleft, DTLHDRDATALEN);
+				jfs_dirent->position = le32_to_cpu(d->index);
+				/*
+				 * d->index should always be valid, but it
+				 * isn't.  fsck.jfs doesn't create the
+				 * directory index for the lost+found
+				 * directory.  Rather than let it go,
+				 * we can try to fix it.
+				 */
+				if ((jfs_dirent->position < 2) ||
+				    (jfs_dirent->position >=
+				     JFS_IP(ip)->next_index)) {
+					if (!page_fixed && !isReadOnly(ip)) {
+						fix_page = 1;
+						/*
+						 * setting overflow and setting
+						 * index to i will cause the
+						 * same page to be processed
+						 * again starting here
+						 */
+						overflow = 1;
+						index = i;
+						break;
+					}
+					jfs_dirent->position = unique_pos++;
+				}
+				/*
+				 * We add 1 to the index because we may
+				 * use a value of 2 internally, and NFSv4
+				 * doesn't like that.
+				 */
+				jfs_dirent->position++;
+			} else {
+				jfs_dirent->position = dtpos;
+				len = min(d_namleft, DTLHDRDATALEN_LEGACY);
+			}
+
+			/* copy the name of head/only segment */
+			outlen = jfs_strfromUCS_le(name_ptr, d->name, len,
+						   codepage);
+			jfs_dirent->name_len = outlen;
+
+			/* copy name in the additional segment(s) */
+			next = d->next;
+			while (next >= 0) {
+				t = (struct dtslot *) & p->slot[next];
+				name_ptr += outlen;
+				d_namleft -= len;
+				/* Sanity Check */
+				if (d_namleft == 0) {
+					jfs_error(ip->i_sb,
+						  "JFS:Dtree error: ino = %ld, bn=%lld, index = %d\n",
+						  (long)ip->i_ino,
+						  (long long)bn,
+						  i);
+					goto skip_one;
+				}
+				len = min(d_namleft, DTSLOTDATALEN);
+				outlen = jfs_strfromUCS_le(name_ptr, t->name,
+							   len, codepage);
+				jfs_dirent->name_len += outlen;
+
+				next = t->next;
+			}
+
+			jfs_dirents++;
+			jfs_dirent = next_jfs_dirent(jfs_dirent);
+skip_one:
+			if (!do_index)
+				dtoffset->index++;
+		}
+
+		if (!overflow) {
+			/* Point to next leaf page */
+			if (p->header.flag & BT_ROOT)
+				bn = 0;
+			else {
+				bn = le64_to_cpu(p->header.next);
+				index = 0;
+				/* update offset (pn:index) for new page */
+				if (!do_index) {
+					dtoffset->pn++;
+					dtoffset->index = 0;
+				}
+			}
+			page_fixed = 0;
+		}
+
+		/* unpin previous leaf page */
+		DT_PUTPAGE(mp);
+
+		jfs_dirent = (struct jfs_dirent *) dirent_buf;
+		while (jfs_dirents--) {
+			ctx->pos = jfs_dirent->position;
+			if (!dir_emit(ctx, jfs_dirent->name,
+				    jfs_dirent->name_len,
+				    jfs_dirent->ino, DT_UNKNOWN))
+				goto out;
+			jfs_dirent = next_jfs_dirent(jfs_dirent);
+		}
+
+		if (fix_page) {
+			add_missing_indices(ip, bn);
+			page_fixed = 1;
+		}
+
+		if (!overflow && (bn == 0)) {
+			ctx->pos = DIREND;
+			break;
+		}
+
+		DT_GETPAGE(ip, bn, mp, PSIZE, p, rc);
+		if (rc) {
+			free_page(dirent_buf);
+			return rc;
+		}
+	}
+
+      out:
+	free_page(dirent_buf);
+
+	return rc;
+}
+
+
+/*
+ *	dtReadFirst()
+ *
+ * function: get the leftmost page of the directory
+ */
+static int dtReadFirst(struct inode *ip, struct btstack * btstack)
+{
+	int rc = 0;
+	s64 bn;
+	int psize = 288;	/* initial in-line directory */
+	struct metapage *mp;
+	dtpage_t *p;
+	s8 *stbl;
+	struct btframe *btsp;
+	pxd_t *xd;
+
+	BT_CLR(btstack);	/* reset stack */
+
+	/*
+	 *	descend leftmost path of the tree
+	 *
+	 * by convention, root bn = 0.
+	 */
+	for (bn = 0;;) {
+		DT_GETPAGE(ip, bn, mp, psize, p, rc);
+		if (rc)
+			return rc;
+
+		/*
+		 * leftmost leaf page
+		 */
+		if (p->header.flag & BT_LEAF) {
+			/* return leftmost entry */
+			btsp = btstack->top;
+			btsp->bn = bn;
+			btsp->index = 0;
+			btsp->mp = mp;
+
+			return 0;
+		}
+
+		/*
+		 * descend down to leftmost child page
+		 */
+		if (BT_STACK_FULL(btstack)) {
+			DT_PUTPAGE(mp);
+			jfs_error(ip->i_sb, "btstack overrun\n");
+			BT_STACK_DUMP(btstack);
+			return -EIO;
+		}
+		/* push (bn, index) of the parent page/entry */
+		BT_PUSH(btstack, bn, 0);
+
+		/* get the leftmost entry */
+		stbl = DT_GETSTBL(p);
+		xd = (pxd_t *) & p->slot[stbl[0]];
+
+		/* get the child page block address */
+		bn = addressPXD(xd);
+		psize = lengthPXD(xd) << JFS_SBI(ip->i_sb)->l2bsize;
+
+		/* unpin the parent page */
+		DT_PUTPAGE(mp);
+	}
+}
+
+
+/*
+ *	dtReadNext()
+ *
+ * function: get the page of the specified offset (pn:index)
+ *
+ * return: if (offset > eof), bn = -1;
+ *
+ * note: if index > nextindex of the target leaf page,
+ * start with 1st entry of next leaf page;
+ */
+static int dtReadNext(struct inode *ip, loff_t * offset,
+		      struct btstack * btstack)
+{
+	int rc = 0;
+	struct dtoffset {
+		s16 pn;
+		s16 index;
+		s32 unused;
+	} *dtoffset = (struct dtoffset *) offset;
+	s64 bn;
+	struct metapage *mp;
+	dtpage_t *p;
+	int index;
+	int pn;
+	s8 *stbl;
+	struct btframe *btsp, *parent;
+	pxd_t *xd;
+
+	/*
+	 * get leftmost leaf page pinned
+	 */
+	if ((rc = dtReadFirst(ip, btstack)))
+		return rc;
+
+	/* get leaf page */
+	DT_GETSEARCH(ip, btstack->top, bn, mp, p, index);
+
+	/* get the start offset (pn:index) */
+	pn = dtoffset->pn - 1;	/* Now pn = 0 represents leftmost leaf */
+	index = dtoffset->index;
+
+	/* start at leftmost page ? */
+	if (pn == 0) {
+		/* offset beyond eof ? */
+		if (index < p->header.nextindex)
+			goto out;
+
+		if (p->header.flag & BT_ROOT) {
+			bn = -1;
+			goto out;
+		}
+
+		/* start with 1st entry of next leaf page */
+		dtoffset->pn++;
+		dtoffset->index = index = 0;
+		goto a;
+	}
+
+	/* start at non-leftmost page: scan parent pages for large pn */
+	if (p->header.flag & BT_ROOT) {
+		bn = -1;
+		goto out;
+	}
+
+	/* start after next leaf page ? */
+	if (pn > 1)
+		goto b;
+
+	/* get leaf page pn = 1 */
+      a:
+	bn = le64_to_cpu(p->header.next);
+
+	/* unpin leaf page */
+	DT_PUTPAGE(mp);
+
+	/* offset beyond eof ? */
+	if (bn == 0) {
+		bn = -1;
+		goto out;
+	}
+
+	goto c;
+
+	/*
+	 * scan last internal page level to get target leaf page
+	 */
+      b:
+	/* unpin leftmost leaf page */
+	DT_PUTPAGE(mp);
+
+	/* get left most parent page */
+	btsp = btstack->top;
+	parent = btsp - 1;
+	bn = parent->bn;
+	DT_GETPAGE(ip, bn, mp, PSIZE, p, rc);
+	if (rc)
+		return rc;
+
+	/* scan parent pages at last internal page level */
+	while (pn >= p->header.nextindex) {
+		pn -= p->header.nextindex;
+
+		/* get next parent page address */
+		bn = le64_to_cpu(p->header.next);
+
+		/* unpin current parent page */
+		DT_PUTPAGE(mp);
+
+		/* offset beyond eof ? */
+		if (bn == 0) {
+			bn = -1;
+			goto out;
+		}
+
+		/* get next parent page */
+		DT_GETPAGE(ip, bn, mp, PSIZE, p, rc);
+		if (rc)
+			return rc;
+
+		/* update parent page stack frame */
+		parent->bn = bn;
+	}
+
+	/* get leaf page address */
+	stbl = DT_GETSTBL(p);
+	xd = (pxd_t *) & p->slot[stbl[pn]];
+	bn = addressPXD(xd);
+
+	/* unpin parent page */
+	DT_PUTPAGE(mp);
+
+	/*
+	 * get target leaf page
+	 */
+      c:
+	DT_GETPAGE(ip, bn, mp, PSIZE, p, rc);
+	if (rc)
+		return rc;
+
+	/*
+	 * leaf page has been completed:
+	 * start with 1st entry of next leaf page
+	 */
+	if (index >= p->header.nextindex) {
+		bn = le64_to_cpu(p->header.next);
+
+		/* unpin leaf page */
+		DT_PUTPAGE(mp);
+
+		/* offset beyond eof ? */
+		if (bn == 0) {
+			bn = -1;
+			goto out;
+		}
+
+		/* get next leaf page */
+		DT_GETPAGE(ip, bn, mp, PSIZE, p, rc);
+		if (rc)
+			return rc;
+
+		/* start with 1st entry of next leaf page */
+		dtoffset->pn++;
+		dtoffset->index = 0;
+	}
+
+      out:
+	/* return target leaf page pinned */
+	btsp = btstack->top;
+	btsp->bn = bn;
+	btsp->index = dtoffset->index;
+	btsp->mp = mp;
+
+	return 0;
+}
+
+
+/*
+ *	dtCompare()
+ *
+ * function: compare search key with an internal entry
+ *
+ * return:
+ *	< 0 if k is < record
+ *	= 0 if k is = record
+ *	> 0 if k is > record
+ */
+static int dtCompare(struct component_name * key,	/* search key */
+		     dtpage_t * p,	/* directory page */
+		     int si)
+{				/* entry slot index */
+	wchar_t *kname;
+	__le16 *name;
+	int klen, namlen, len, rc;
+	struct idtentry *ih;
+	struct dtslot *t;
+
+	/*
+	 * force the left-most key on internal pages, at any level of
+	 * the tree, to be less than any search key.
+	 * this obviates having to update the leftmost key on an internal
+	 * page when the user inserts a new key in the tree smaller than
+	 * anything that has been stored.
+	 *
+	 * (? if/when dtSearch() narrows down to 1st entry (index = 0),
+	 * at any internal page at any level of the tree,
+	 * it descends to child of the entry anyway -
+	 * ? make the entry as min size dummy entry)
+	 *
+	 * if (e->index == 0 && h->prevpg == P_INVALID && !(h->flags & BT_LEAF))
+	 * return (1);
+	 */
+
+	kname = key->name;
+	klen = key->namlen;
+
+	ih = (struct idtentry *) & p->slot[si];
+	si = ih->next;
+	name = ih->name;
+	namlen = ih->namlen;
+	len = min(namlen, DTIHDRDATALEN);
+
+	/* compare with head/only segment */
+	len = min(klen, len);
+	if ((rc = UniStrncmp_le(kname, name, len)))
+		return rc;
+
+	klen -= len;
+	namlen -= len;
+
+	/* compare with additional segment(s) */
+	kname += len;
+	while (klen > 0 && namlen > 0) {
+		/* compare with next name segment */
+		t = (struct dtslot *) & p->slot[si];
+		len = min(namlen, DTSLOTDATALEN);
+		len = min(klen, len);
+		name = t->name;
+		if ((rc = UniStrncmp_le(kname, name, len)))
+			return rc;
+
+		klen -= len;
+		namlen -= len;
+		kname += len;
+		si = t->next;
+	}
+
+	return (klen - namlen);
+}
+
+
+
+
+/*
+ *	ciCompare()
+ *
+ * function: compare search key with an (leaf/internal) entry
+ *
+ * return:
+ *	< 0 if k is < record
+ *	= 0 if k is = record
+ *	> 0 if k is > record
+ */
+static int ciCompare(struct component_name * key,	/* search key */
+		     dtpage_t * p,	/* directory page */
+		     int si,	/* entry slot index */
+		     int flag)
+{
+	wchar_t *kname, x;
+	__le16 *name;
+	int klen, namlen, len, rc;
+	struct ldtentry *lh;
+	struct idtentry *ih;
+	struct dtslot *t;
+	int i;
+
+	/*
+	 * force the left-most key on internal pages, at any level of
+	 * the tree, to be less than any search key.
+	 * this obviates having to update the leftmost key on an internal
+	 * page when the user inserts a new key in the tree smaller than
+	 * anything that has been stored.
+	 *
+	 * (? if/when dtSearch() narrows down to 1st entry (index = 0),
+	 * at any internal page at any level of the tree,
+	 * it descends to child of the entry anyway -
+	 * ? make the entry as min size dummy entry)
+	 *
+	 * if (e->index == 0 && h->prevpg == P_INVALID && !(h->flags & BT_LEAF))
+	 * return (1);
+	 */
+
+	kname = key->name;
+	klen = key->namlen;
+
+	/*
+	 * leaf page entry
+	 */
+	if (p->header.flag & BT_LEAF) {
+		lh = (struct ldtentry *) & p->slot[si];
+		si = lh->next;
+		name = lh->name;
+		namlen = lh->namlen;
+		if (flag & JFS_DIR_INDEX)
+			len = min(namlen, DTLHDRDATALEN);
+		else
+			len = min(namlen, DTLHDRDATALEN_LEGACY);
+	}
+	/*
+	 * internal page entry
+	 */
+	else {
+		ih = (struct idtentry *) & p->slot[si];
+		si = ih->next;
+		name = ih->name;
+		namlen = ih->namlen;
+		len = min(namlen, DTIHDRDATALEN);
+	}
+
+	/* compare with head/only segment */
+	len = min(klen, len);
+	for (i = 0; i < len; i++, kname++, name++) {
+		/* only uppercase if case-insensitive support is on */
+		if ((flag & JFS_OS2) == JFS_OS2)
+			x = UniToupper(le16_to_cpu(*name));
+		else
+			x = le16_to_cpu(*name);
+		if ((rc = *kname - x))
+			return rc;
+	}
+
+	klen -= len;
+	namlen -= len;
+
+	/* compare with additional segment(s) */
+	while (klen > 0 && namlen > 0) {
+		/* compare with next name segment */
+		t = (struct dtslot *) & p->slot[si];
+		len = min(namlen, DTSLOTDATALEN);
+		len = min(klen, len);
+		name = t->name;
+		for (i = 0; i < len; i++, kname++, name++) {
+			/* only uppercase if case-insensitive support is on */
+			if ((flag & JFS_OS2) == JFS_OS2)
+				x = UniToupper(le16_to_cpu(*name));
+			else
+				x = le16_to_cpu(*name);
+
+			if ((rc = *kname - x))
+				return rc;
+		}
+
+		klen -= len;
+		namlen -= len;
+		si = t->next;
+	}
+
+	return (klen - namlen);
+}
+
+
+/*
+ *	ciGetLeafPrefixKey()
+ *
+ * function: compute prefix of suffix compression
+ *	     from two adjacent leaf entries
+ *	     across page boundary
+ *
+ * return: non-zero on error
+ *
+ */
+static int ciGetLeafPrefixKey(dtpage_t * lp, int li, dtpage_t * rp,
+			       int ri, struct component_name * key, int flag)
+{
+	int klen, namlen;
+	wchar_t *pl, *pr, *kname;
+	struct component_name lkey;
+	struct component_name rkey;
+
+	lkey.name = kmalloc_array(JFS_NAME_MAX + 1, sizeof(wchar_t),
+					GFP_KERNEL);
+	if (lkey.name == NULL)
+		return -ENOMEM;
+
+	rkey.name = kmalloc_array(JFS_NAME_MAX + 1, sizeof(wchar_t),
+					GFP_KERNEL);
+	if (rkey.name == NULL) {
+		kfree(lkey.name);
+		return -ENOMEM;
+	}
+
+	/* get left and right key */
+	dtGetKey(lp, li, &lkey, flag);
+	lkey.name[lkey.namlen] = 0;
+
+	if ((flag & JFS_OS2) == JFS_OS2)
+		ciToUpper(&lkey);
+
+	dtGetKey(rp, ri, &rkey, flag);
+	rkey.name[rkey.namlen] = 0;
+
+
+	if ((flag & JFS_OS2) == JFS_OS2)
+		ciToUpper(&rkey);
+
+	/* compute prefix */
+	klen = 0;
+	kname = key->name;
+	namlen = min(lkey.namlen, rkey.namlen);
+	for (pl = lkey.name, pr = rkey.name;
+	     namlen; pl++, pr++, namlen--, klen++, kname++) {
+		*kname = *pr;
+		if (*pl != *pr) {
+			key->namlen = klen + 1;
+			goto free_names;
+		}
+	}
+
+	/* l->namlen <= r->namlen since l <= r */
+	if (lkey.namlen < rkey.namlen) {
+		*kname = *pr;
+		key->namlen = klen + 1;
+	} else			/* l->namelen == r->namelen */
+		key->namlen = klen;
+
+free_names:
+	kfree(lkey.name);
+	kfree(rkey.name);
+	return 0;
+}
+
+
+
+/*
+ *	dtGetKey()
+ *
+ * function: get key of the entry
+ */
+static void dtGetKey(dtpage_t * p, int i,	/* entry index */
+		     struct component_name * key, int flag)
+{
+	int si;
+	s8 *stbl;
+	struct ldtentry *lh;
+	struct idtentry *ih;
+	struct dtslot *t;
+	int namlen, len;
+	wchar_t *kname;
+	__le16 *name;
+
+	/* get entry */
+	stbl = DT_GETSTBL(p);
+	si = stbl[i];
+	if (p->header.flag & BT_LEAF) {
+		lh = (struct ldtentry *) & p->slot[si];
+		si = lh->next;
+		namlen = lh->namlen;
+		name = lh->name;
+		if (flag & JFS_DIR_INDEX)
+			len = min(namlen, DTLHDRDATALEN);
+		else
+			len = min(namlen, DTLHDRDATALEN_LEGACY);
+	} else {
+		ih = (struct idtentry *) & p->slot[si];
+		si = ih->next;
+		namlen = ih->namlen;
+		name = ih->name;
+		len = min(namlen, DTIHDRDATALEN);
+	}
+
+	key->namlen = namlen;
+	kname = key->name;
+
+	/*
+	 * move head/only segment
+	 */
+	UniStrncpy_from_le(kname, name, len);
+
+	/*
+	 * move additional segment(s)
+	 */
+	while (si >= 0) {
+		/* get next segment */
+		t = &p->slot[si];
+		kname += len;
+		namlen -= len;
+		len = min(namlen, DTSLOTDATALEN);
+		UniStrncpy_from_le(kname, t->name, len);
+
+		si = t->next;
+	}
+}
+
+
+/*
+ *	dtInsertEntry()
+ *
+ * function: allocate free slot(s) and
+ *	     write a leaf/internal entry
+ *
+ * return: entry slot index
+ */
+static void dtInsertEntry(dtpage_t * p, int index, struct component_name * key,
+			  ddata_t * data, struct dt_lock ** dtlock)
+{
+	struct dtslot *h, *t;
+	struct ldtentry *lh = NULL;
+	struct idtentry *ih = NULL;
+	int hsi, fsi, klen, len, nextindex;
+	wchar_t *kname;
+	__le16 *name;
+	s8 *stbl;
+	pxd_t *xd;
+	struct dt_lock *dtlck = *dtlock;
+	struct lv *lv;
+	int xsi, n;
+	s64 bn = 0;
+	struct metapage *mp = NULL;
+
+	klen = key->namlen;
+	kname = key->name;
+
+	/* allocate a free slot */
+	hsi = fsi = p->header.freelist;
+	h = &p->slot[fsi];
+	p->header.freelist = h->next;
+	--p->header.freecnt;
+
+	/* open new linelock */
+	if (dtlck->index >= dtlck->maxcnt)
+		dtlck = (struct dt_lock *) txLinelock(dtlck);
+
+	lv = & dtlck->lv[dtlck->index];
+	lv->offset = hsi;
+
+	/* write head/only segment */
+	if (p->header.flag & BT_LEAF) {
+		lh = (struct ldtentry *) h;
+		lh->next = h->next;
+		lh->inumber = cpu_to_le32(data->leaf.ino);
+		lh->namlen = klen;
+		name = lh->name;
+		if (data->leaf.ip) {
+			len = min(klen, DTLHDRDATALEN);
+			if (!(p->header.flag & BT_ROOT))
+				bn = addressPXD(&p->header.self);
+			lh->index = cpu_to_le32(add_index(data->leaf.tid,
+							  data->leaf.ip,
+							  bn, index));
+		} else
+			len = min(klen, DTLHDRDATALEN_LEGACY);
+	} else {
+		ih = (struct idtentry *) h;
+		ih->next = h->next;
+		xd = (pxd_t *) ih;
+		*xd = data->xd;
+		ih->namlen = klen;
+		name = ih->name;
+		len = min(klen, DTIHDRDATALEN);
+	}
+
+	UniStrncpy_to_le(name, kname, len);
+
+	n = 1;
+	xsi = hsi;
+
+	/* write additional segment(s) */
+	t = h;
+	klen -= len;
+	while (klen) {
+		/* get free slot */
+		fsi = p->header.freelist;
+		t = &p->slot[fsi];
+		p->header.freelist = t->next;
+		--p->header.freecnt;
+
+		/* is next slot contiguous ? */
+		if (fsi != xsi + 1) {
+			/* close current linelock */
+			lv->length = n;
+			dtlck->index++;
+
+			/* open new linelock */
+			if (dtlck->index < dtlck->maxcnt)
+				lv++;
+			else {
+				dtlck = (struct dt_lock *) txLinelock(dtlck);
+				lv = & dtlck->lv[0];
+			}
+
+			lv->offset = fsi;
+			n = 0;
+		}
+
+		kname += len;
+		len = min(klen, DTSLOTDATALEN);
+		UniStrncpy_to_le(t->name, kname, len);
+
+		n++;
+		xsi = fsi;
+		klen -= len;
+	}
+
+	/* close current linelock */
+	lv->length = n;
+	dtlck->index++;
+
+	*dtlock = dtlck;
+
+	/* terminate last/only segment */
+	if (h == t) {
+		/* single segment entry */
+		if (p->header.flag & BT_LEAF)
+			lh->next = -1;
+		else
+			ih->next = -1;
+	} else
+		/* multi-segment entry */
+		t->next = -1;
+
+	/* if insert into middle, shift right succeeding entries in stbl */
+	stbl = DT_GETSTBL(p);
+	nextindex = p->header.nextindex;
+	if (index < nextindex) {
+		memmove(stbl + index + 1, stbl + index, nextindex - index);
+
+		if ((p->header.flag & BT_LEAF) && data->leaf.ip) {
+			s64 lblock;
+
+			/*
+			 * Need to update slot number for entries that moved
+			 * in the stbl
+			 */
+			mp = NULL;
+			for (n = index + 1; n <= nextindex; n++) {
+				lh = (struct ldtentry *) & (p->slot[stbl[n]]);
+				modify_index(data->leaf.tid, data->leaf.ip,
+					     le32_to_cpu(lh->index), bn, n,
+					     &mp, &lblock);
+			}
+			if (mp)
+				release_metapage(mp);
+		}
+	}
+
+	stbl[index] = hsi;
+
+	/* advance next available entry index of stbl */
+	++p->header.nextindex;
+}
+
+
+/*
+ *	dtMoveEntry()
+ *
+ * function: move entries from split/left page to new/right page
+ *
+ *	nextindex of dst page and freelist/freecnt of both pages
+ *	are updated.
+ */
+static void dtMoveEntry(dtpage_t * sp, int si, dtpage_t * dp,
+			struct dt_lock ** sdtlock, struct dt_lock ** ddtlock,
+			int do_index)
+{
+	int ssi, next;		/* src slot index */
+	int di;			/* dst entry index */
+	int dsi;		/* dst slot index */
+	s8 *sstbl, *dstbl;	/* sorted entry table */
+	int snamlen, len;
+	struct ldtentry *slh, *dlh = NULL;
+	struct idtentry *sih, *dih = NULL;
+	struct dtslot *h, *s, *d;
+	struct dt_lock *sdtlck = *sdtlock, *ddtlck = *ddtlock;
+	struct lv *slv, *dlv;
+	int xssi, ns, nd;
+	int sfsi;
+
+	sstbl = (s8 *) & sp->slot[sp->header.stblindex];
+	dstbl = (s8 *) & dp->slot[dp->header.stblindex];
+
+	dsi = dp->header.freelist;	/* first (whole page) free slot */
+	sfsi = sp->header.freelist;
+
+	/* linelock destination entry slot */
+	dlv = & ddtlck->lv[ddtlck->index];
+	dlv->offset = dsi;
+
+	/* linelock source entry slot */
+	slv = & sdtlck->lv[sdtlck->index];
+	slv->offset = sstbl[si];
+	xssi = slv->offset - 1;
+
+	/*
+	 * move entries
+	 */
+	ns = nd = 0;
+	for (di = 0; si < sp->header.nextindex; si++, di++) {
+		ssi = sstbl[si];
+		dstbl[di] = dsi;
+
+		/* is next slot contiguous ? */
+		if (ssi != xssi + 1) {
+			/* close current linelock */
+			slv->length = ns;
+			sdtlck->index++;
+
+			/* open new linelock */
+			if (sdtlck->index < sdtlck->maxcnt)
+				slv++;
+			else {
+				sdtlck = (struct dt_lock *) txLinelock(sdtlck);
+				slv = & sdtlck->lv[0];
+			}
+
+			slv->offset = ssi;
+			ns = 0;
+		}
+
+		/*
+		 * move head/only segment of an entry
+		 */
+		/* get dst slot */
+		h = d = &dp->slot[dsi];
+
+		/* get src slot and move */
+		s = &sp->slot[ssi];
+		if (sp->header.flag & BT_LEAF) {
+			/* get source entry */
+			slh = (struct ldtentry *) s;
+			dlh = (struct ldtentry *) h;
+			snamlen = slh->namlen;
+
+			if (do_index) {
+				len = min(snamlen, DTLHDRDATALEN);
+				dlh->index = slh->index; /* little-endian */
+			} else
+				len = min(snamlen, DTLHDRDATALEN_LEGACY);
+
+			memcpy(dlh, slh, 6 + len * 2);
+
+			next = slh->next;
+
+			/* update dst head/only segment next field */
+			dsi++;
+			dlh->next = dsi;
+		} else {
+			sih = (struct idtentry *) s;
+			snamlen = sih->namlen;
+
+			len = min(snamlen, DTIHDRDATALEN);
+			dih = (struct idtentry *) h;
+			memcpy(dih, sih, 10 + len * 2);
+			next = sih->next;
+
+			dsi++;
+			dih->next = dsi;
+		}
+
+		/* free src head/only segment */
+		s->next = sfsi;
+		s->cnt = 1;
+		sfsi = ssi;
+
+		ns++;
+		nd++;
+		xssi = ssi;
+
+		/*
+		 * move additional segment(s) of the entry
+		 */
+		snamlen -= len;
+		while ((ssi = next) >= 0) {
+			/* is next slot contiguous ? */
+			if (ssi != xssi + 1) {
+				/* close current linelock */
+				slv->length = ns;
+				sdtlck->index++;
+
+				/* open new linelock */
+				if (sdtlck->index < sdtlck->maxcnt)
+					slv++;
+				else {
+					sdtlck =
+					    (struct dt_lock *)
+					    txLinelock(sdtlck);
+					slv = & sdtlck->lv[0];
+				}
+
+				slv->offset = ssi;
+				ns = 0;
+			}
+
+			/* get next source segment */
+			s = &sp->slot[ssi];
+
+			/* get next destination free slot */
+			d++;
+
+			len = min(snamlen, DTSLOTDATALEN);
+			UniStrncpy_le(d->name, s->name, len);
+
+			ns++;
+			nd++;
+			xssi = ssi;
+
+			dsi++;
+			d->next = dsi;
+
+			/* free source segment */
+			next = s->next;
+			s->next = sfsi;
+			s->cnt = 1;
+			sfsi = ssi;
+
+			snamlen -= len;
+		}		/* end while */
+
+		/* terminate dst last/only segment */
+		if (h == d) {
+			/* single segment entry */
+			if (dp->header.flag & BT_LEAF)
+				dlh->next = -1;
+			else
+				dih->next = -1;
+		} else
+			/* multi-segment entry */
+			d->next = -1;
+	}			/* end for */
+
+	/* close current linelock */
+	slv->length = ns;
+	sdtlck->index++;
+	*sdtlock = sdtlck;
+
+	dlv->length = nd;
+	ddtlck->index++;
+	*ddtlock = ddtlck;
+
+	/* update source header */
+	sp->header.freelist = sfsi;
+	sp->header.freecnt += nd;
+
+	/* update destination header */
+	dp->header.nextindex = di;
+
+	dp->header.freelist = dsi;
+	dp->header.freecnt -= nd;
+}
+
+
+/*
+ *	dtDeleteEntry()
+ *
+ * function: free a (leaf/internal) entry
+ *
+ * log freelist header, stbl, and each segment slot of entry
+ * (even though last/only segment next field is modified,
+ * physical image logging requires all segment slots of
+ * the entry logged to avoid applying previous updates
+ * to the same slots)
+ */
+static void dtDeleteEntry(dtpage_t * p, int fi, struct dt_lock ** dtlock)
+{
+	int fsi;		/* free entry slot index */
+	s8 *stbl;
+	struct dtslot *t;
+	int si, freecnt;
+	struct dt_lock *dtlck = *dtlock;
+	struct lv *lv;
+	int xsi, n;
+
+	/* get free entry slot index */
+	stbl = DT_GETSTBL(p);
+	fsi = stbl[fi];
+
+	/* open new linelock */
+	if (dtlck->index >= dtlck->maxcnt)
+		dtlck = (struct dt_lock *) txLinelock(dtlck);
+	lv = & dtlck->lv[dtlck->index];
+
+	lv->offset = fsi;
+
+	/* get the head/only segment */
+	t = &p->slot[fsi];
+	if (p->header.flag & BT_LEAF)
+		si = ((struct ldtentry *) t)->next;
+	else
+		si = ((struct idtentry *) t)->next;
+	t->next = si;
+	t->cnt = 1;
+
+	n = freecnt = 1;
+	xsi = fsi;
+
+	/* find the last/only segment */
+	while (si >= 0) {
+		/* is next slot contiguous ? */
+		if (si != xsi + 1) {
+			/* close current linelock */
+			lv->length = n;
+			dtlck->index++;
+
+			/* open new linelock */
+			if (dtlck->index < dtlck->maxcnt)
+				lv++;
+			else {
+				dtlck = (struct dt_lock *) txLinelock(dtlck);
+				lv = & dtlck->lv[0];
+			}
+
+			lv->offset = si;
+			n = 0;
+		}
+
+		n++;
+		xsi = si;
+		freecnt++;
+
+		t = &p->slot[si];
+		t->cnt = 1;
+		si = t->next;
+	}
+
+	/* close current linelock */
+	lv->length = n;
+	dtlck->index++;
+
+	*dtlock = dtlck;
+
+	/* update freelist */
+	t->next = p->header.freelist;
+	p->header.freelist = fsi;
+	p->header.freecnt += freecnt;
+
+	/* if delete from middle,
+	 * shift left the succedding entries in the stbl
+	 */
+	si = p->header.nextindex;
+	if (fi < si - 1)
+		memmove(&stbl[fi], &stbl[fi + 1], si - fi - 1);
+
+	p->header.nextindex--;
+}
+
+
+/*
+ *	dtTruncateEntry()
+ *
+ * function: truncate a (leaf/internal) entry
+ *
+ * log freelist header, stbl, and each segment slot of entry
+ * (even though last/only segment next field is modified,
+ * physical image logging requires all segment slots of
+ * the entry logged to avoid applying previous updates
+ * to the same slots)
+ */
+static void dtTruncateEntry(dtpage_t * p, int ti, struct dt_lock ** dtlock)
+{
+	int tsi;		/* truncate entry slot index */
+	s8 *stbl;
+	struct dtslot *t;
+	int si, freecnt;
+	struct dt_lock *dtlck = *dtlock;
+	struct lv *lv;
+	int fsi, xsi, n;
+
+	/* get free entry slot index */
+	stbl = DT_GETSTBL(p);
+	tsi = stbl[ti];
+
+	/* open new linelock */
+	if (dtlck->index >= dtlck->maxcnt)
+		dtlck = (struct dt_lock *) txLinelock(dtlck);
+	lv = & dtlck->lv[dtlck->index];
+
+	lv->offset = tsi;
+
+	/* get the head/only segment */
+	t = &p->slot[tsi];
+	ASSERT(p->header.flag & BT_INTERNAL);
+	((struct idtentry *) t)->namlen = 0;
+	si = ((struct idtentry *) t)->next;
+	((struct idtentry *) t)->next = -1;
+
+	n = 1;
+	freecnt = 0;
+	fsi = si;
+	xsi = tsi;
+
+	/* find the last/only segment */
+	while (si >= 0) {
+		/* is next slot contiguous ? */
+		if (si != xsi + 1) {
+			/* close current linelock */
+			lv->length = n;
+			dtlck->index++;
+
+			/* open new linelock */
+			if (dtlck->index < dtlck->maxcnt)
+				lv++;
+			else {
+				dtlck = (struct dt_lock *) txLinelock(dtlck);
+				lv = & dtlck->lv[0];
+			}
+
+			lv->offset = si;
+			n = 0;
+		}
+
+		n++;
+		xsi = si;
+		freecnt++;
+
+		t = &p->slot[si];
+		t->cnt = 1;
+		si = t->next;
+	}
+
+	/* close current linelock */
+	lv->length = n;
+	dtlck->index++;
+
+	*dtlock = dtlck;
+
+	/* update freelist */
+	if (freecnt == 0)
+		return;
+	t->next = p->header.freelist;
+	p->header.freelist = fsi;
+	p->header.freecnt += freecnt;
+}
+
+
+/*
+ *	dtLinelockFreelist()
+ */
+static void dtLinelockFreelist(dtpage_t * p,	/* directory page */
+			       int m,	/* max slot index */
+			       struct dt_lock ** dtlock)
+{
+	int fsi;		/* free entry slot index */
+	struct dtslot *t;
+	int si;
+	struct dt_lock *dtlck = *dtlock;
+	struct lv *lv;
+	int xsi, n;
+
+	/* get free entry slot index */
+	fsi = p->header.freelist;
+
+	/* open new linelock */
+	if (dtlck->index >= dtlck->maxcnt)
+		dtlck = (struct dt_lock *) txLinelock(dtlck);
+	lv = & dtlck->lv[dtlck->index];
+
+	lv->offset = fsi;
+
+	n = 1;
+	xsi = fsi;
+
+	t = &p->slot[fsi];
+	si = t->next;
+
+	/* find the last/only segment */
+	while (si < m && si >= 0) {
+		/* is next slot contiguous ? */
+		if (si != xsi + 1) {
+			/* close current linelock */
+			lv->length = n;
+			dtlck->index++;
+
+			/* open new linelock */
+			if (dtlck->index < dtlck->maxcnt)
+				lv++;
+			else {
+				dtlck = (struct dt_lock *) txLinelock(dtlck);
+				lv = & dtlck->lv[0];
+			}
+
+			lv->offset = si;
+			n = 0;
+		}
+
+		n++;
+		xsi = si;
+
+		t = &p->slot[si];
+		si = t->next;
+	}
+
+	/* close current linelock */
+	lv->length = n;
+	dtlck->index++;
+
+	*dtlock = dtlck;
+}
+
+
+/*
+ * NAME: dtModify
+ *
+ * FUNCTION: Modify the inode number part of a directory entry
+ *
+ * PARAMETERS:
+ *	tid	- Transaction id
+ *	ip	- Inode of parent directory
+ *	key	- Name of entry to be modified
+ *	orig_ino	- Original inode number expected in entry
+ *	new_ino	- New inode number to put into entry
+ *	flag	- JFS_RENAME
+ *
+ * RETURNS:
+ *	-ESTALE	- If entry found does not match orig_ino passed in
+ *	-ENOENT	- If no entry can be found to match key
+ *	0	- If successfully modified entry
+ */
+int dtModify(tid_t tid, struct inode *ip,
+	 struct component_name * key, ino_t * orig_ino, ino_t new_ino, int flag)
+{
+	int rc;
+	s64 bn;
+	struct metapage *mp;
+	dtpage_t *p;
+	int index;
+	struct btstack btstack;
+	struct tlock *tlck;
+	struct dt_lock *dtlck;
+	struct lv *lv;
+	s8 *stbl;
+	int entry_si;		/* entry slot index */
+	struct ldtentry *entry;
+
+	/*
+	 *	search for the entry to modify:
+	 *
+	 * dtSearch() returns (leaf page pinned, index at which to modify).
+	 */
+	if ((rc = dtSearch(ip, key, orig_ino, &btstack, flag)))
+		return rc;
+
+	/* retrieve search result */
+	DT_GETSEARCH(ip, btstack.top, bn, mp, p, index);
+
+	BT_MARK_DIRTY(mp, ip);
+	/*
+	 * acquire a transaction lock on the leaf page of named entry
+	 */
+	tlck = txLock(tid, ip, mp, tlckDTREE | tlckENTRY);
+	dtlck = (struct dt_lock *) & tlck->lock;
+
+	/* get slot index of the entry */
+	stbl = DT_GETSTBL(p);
+	entry_si = stbl[index];
+
+	/* linelock entry */
+	ASSERT(dtlck->index == 0);
+	lv = & dtlck->lv[0];
+	lv->offset = entry_si;
+	lv->length = 1;
+	dtlck->index++;
+
+	/* get the head/only segment */
+	entry = (struct ldtentry *) & p->slot[entry_si];
+
+	/* substitute the inode number of the entry */
+	entry->inumber = cpu_to_le32(new_ino);
+
+	/* unpin the leaf page */
+	DT_PUTPAGE(mp);
+
+	return 0;
+}