OSCL-LXR linux-6.0.1/​fs/​jfs/​jfs_dtree.c	Source navigation Diff markup Identifier search General search
	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // 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;
 }