fs/jffs2/nodelist.c

   1 /*
   2  * JFFS2 -- Journalling Flash File System, Version 2.
   3  *
   4  * Copyright (C) 2001-2003 Red Hat, Inc.
   5  *
   6  * Created by David Woodhouse <dwmw2@infradead.org>
   7  *
   8  * For licensing information, see the file 'LICENCE' in this directory.
   9  *
  10  * $Id: nodelist.c,v 1.103 2005/07/31 08:20:44 dedekind Exp $
  11  *
  12  */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/sched.h>
  16 #include <linux/fs.h>
  17 #include <linux/mtd/mtd.h>
  18 #include <linux/rbtree.h>
  19 #include <linux/crc32.h>
  20 #include <linux/slab.h>
  21 #include <linux/pagemap.h>
  22 #include "nodelist.h"
  23
  24 void jffs2_add_fd_to_list(struct jffs2_sb_info *c, struct jffs2_full_dirent *new, struct jffs2_full_dirent **list)
  25 {
  26         struct jffs2_full_dirent **prev = list;
  27
  28         JFFS2_DBG_DENTLIST("add dirent \"%s\", ino #%u\n", new->name, new->ino);
  29
  30         while ((*prev) && (*prev)->nhash <= new->nhash) {
  31                 if ((*prev)->nhash == new->nhash && !strcmp((*prev)->name, new->name)) {
  32                         /* Duplicate. Free one */
  33                         if (new->version < (*prev)->version) {
  34                                 JFFS2_DBG_DENTLIST("Eep! Marking new dirent node is obsolete, old is \"%s\", ino #%u\n",
  35                                         (*prev)->name, (*prev)->ino);
  36                                 jffs2_mark_node_obsolete(c, new->raw);
  37                                 jffs2_free_full_dirent(new);
  38                         } else {
  39                                 JFFS2_DBG_DENTLIST("marking old dirent \"%s\", ino #%u bsolete\n",
  40                                         (*prev)->name, (*prev)->ino);
  41                                 new->next = (*prev)->next;
  42                                 jffs2_mark_node_obsolete(c, ((*prev)->raw));
  43                                 jffs2_free_full_dirent(*prev);
  44                                 *prev = new;
  45                         }
  46                         return;
  47                 }
  48                 prev = &((*prev)->next);
  49         }
  50         new->next = *prev;
  51         *prev = new;
  52 }
  53
  54 void jffs2_truncate_fragtree(struct jffs2_sb_info *c, struct rb_root *list, uint32_t size)
  55 {
  56         struct jffs2_node_frag *frag = jffs2_lookup_node_frag(list, size);
  57
  58         JFFS2_DBG_FRAGTREE("truncating fragtree to 0x%08x bytes\n", size);
  59
  60         /* We know frag->ofs <= size. That's what lookup does for us */
  61         if (frag && frag->ofs != size) {
  62                 if (frag->ofs+frag->size >= size) {
  63                         JFFS2_DBG_FRAGTREE2("truncating frag 0x%08x-0x%08x\n", frag->ofs, frag->ofs+frag->size);
  64                         frag->size = size - frag->ofs;
  65                 }
  66                 frag = frag_next(frag);
  67         }
  68         while (frag && frag->ofs >= size) {
  69                 struct jffs2_node_frag *next = frag_next(frag);
  70
  71                 JFFS2_DBG_FRAGTREE("removing frag 0x%08x-0x%08x\n", frag->ofs, frag->ofs+frag->size);
  72                 frag_erase(frag, list);
  73                 jffs2_obsolete_node_frag(c, frag);
  74                 frag = next;
  75         }
  76 }
  77
  78 void jffs2_obsolete_node_frag(struct jffs2_sb_info *c, struct jffs2_node_frag *this)
  79 {
  80         if (this->node) {
  81                 this->node->frags--;
  82                 if (!this->node->frags) {
  83                         /* The node has no valid frags left. It's totally obsoleted */
  84                         JFFS2_DBG_FRAGTREE2("marking old node @0x%08x (0x%04x-0x%04x) obsolete\n",
  85                                 ref_offset(this->node->raw), this->node->ofs, this->node->ofs+this->node->size);
  86                         jffs2_mark_node_obsolete(c, this->node->raw);
  87                         jffs2_free_full_dnode(this->node);
  88                 } else {
  89                         JFFS2_DBG_FRAGTREE2("marking old node @0x%08x (0x%04x-0x%04x) REF_NORMAL. frags is %d\n",
  90                                 ref_offset(this->node->raw), this->node->ofs, this->node->ofs+this->node->size, this->node->frags);
  91                         mark_ref_normal(this->node->raw);
  92                 }
  93
  94         }
  95         jffs2_free_node_frag(this);
  96 }
  97
  98 static void jffs2_fragtree_insert(struct jffs2_node_frag *newfrag, struct jffs2_node_frag *base)
  99 {
 100         struct rb_node *parent = &base->rb;
 101         struct rb_node **link = &parent;
 102
 103         JFFS2_DBG_FRAGTREE2("insert frag (0x%04x-0x%04x)\n", newfrag->ofs, newfrag->ofs + newfrag->size);
 104
 105         while (*link) {
 106                 parent = *link;
 107                 base = rb_entry(parent, struct jffs2_node_frag, rb);
 108
 109                 JFFS2_DBG_FRAGTREE2("considering frag at 0x%08x\n", base->ofs);
 110                 if (newfrag->ofs > base->ofs)
 111                         link = &base->rb.rb_right;
 112                 else if (newfrag->ofs < base->ofs)
 113                         link = &base->rb.rb_left;
 114                 else {
 115                         JFFS2_ERROR("duplicate frag at %08x (%p,%p)\n", newfrag->ofs, newfrag, base);
 116                         BUG();
 117                 }
 118         }
 119
 120         rb_link_node(&newfrag->rb, &base->rb, link);
 121 }
 122
 123 /* Doesn't set inode->i_size */
 124 static int jffs2_add_frag_to_fragtree(struct jffs2_sb_info *c, struct rb_root *list, struct jffs2_node_frag *newfrag)
 125 {
 126         struct jffs2_node_frag *this;
 127         uint32_t lastend;
 128
 129         /* Skip all the nodes which are completed before this one starts */
 130         this = jffs2_lookup_node_frag(list, newfrag->node->ofs);
 131
 132         if (this) {
 133                 JFFS2_DBG_FRAGTREE2("lookup gave frag 0x%04x-0x%04x; phys 0x%08x (*%p)\n",
 134                           this->ofs, this->ofs+this->size, this->node?(ref_offset(this->node->raw)):0xffffffff, this);
 135                 lastend = this->ofs + this->size;
 136         } else {
 137                 JFFS2_DBG_FRAGTREE2("lookup gave no frag\n");
 138                 lastend = 0;
 139         }
 140
 141         /* See if we ran off the end of the list */
 142         if (lastend <= newfrag->ofs) {
 143                 /* We did */
 144
 145                 /* Check if 'this' node was on the same page as the new node.
 146                    If so, both 'this' and the new node get marked REF_NORMAL so
 147                    the GC can take a look.
 148                 */
 149                 if (lastend && (lastend-1) >> PAGE_CACHE_SHIFT == newfrag->ofs >> PAGE_CACHE_SHIFT) {
 150                         if (this->node)
 151                                 mark_ref_normal(this->node->raw);
 152                         mark_ref_normal(newfrag->node->raw);
 153                 }
 154
 155                 if (lastend < newfrag->node->ofs) {
 156                         /* ... and we need to put a hole in before the new node */
 157                         struct jffs2_node_frag *holefrag = jffs2_alloc_node_frag();
 158                         if (!holefrag) {
 159                                 jffs2_free_node_frag(newfrag);
 160                                 return -ENOMEM;
 161                         }
 162                         holefrag->ofs = lastend;
 163                         holefrag->size = newfrag->node->ofs - lastend;
 164                         holefrag->node = NULL;
 165                         if (this) {
 166                                 /* By definition, the 'this' node has no right-hand child,
 167                                    because there are no frags with offset greater than it.
 168                                    So that's where we want to put the hole */
 169                                 JFFS2_DBG_FRAGTREE2("adding hole frag (%p) on right of node at (%p)\n", holefrag, this);
 170                                 rb_link_node(&holefrag->rb, &this->rb, &this->rb.rb_right);
 171                         } else {
 172                                 JFFS2_DBG_FRAGTREE2("adding hole frag (%p) at root of tree\n", holefrag);
 173                                 rb_link_node(&holefrag->rb, NULL, &list->rb_node);
 174                         }
 175                         rb_insert_color(&holefrag->rb, list);
 176                         this = holefrag;
 177                 }
 178                 if (this) {
 179                         /* By definition, the 'this' node has no right-hand child,
 180                            because there are no frags with offset greater than it.
 181                            So that's where we want to put new fragment */
 182                         JFFS2_DBG_FRAGTREE2("adding new frag (%p) on right of node at (%p)\n", newfrag, this);
 183                         rb_link_node(&newfrag->rb, &this->rb, &this->rb.rb_right);
 184                 } else {
 185                         JFFS2_DBG_FRAGTREE2("adding new frag (%p) at root of tree\n", newfrag);
 186                         rb_link_node(&newfrag->rb, NULL, &list->rb_node);
 187                 }
 188                 rb_insert_color(&newfrag->rb, list);
 189                 return 0;
 190         }
 191
 192         JFFS2_DBG_FRAGTREE2("dealing with frag 0x%04x-0x%04x; phys 0x%08x (*%p)\n",
 193                   this->ofs, this->ofs+this->size, this->node?(ref_offset(this->node->raw)):0xffffffff, this);
 194
 195         /* OK. 'this' is pointing at the first frag that newfrag->ofs at least partially obsoletes,
 196          * - i.e. newfrag->ofs < this->ofs+this->size && newfrag->ofs >= this->ofs
 197          */
 198         if (newfrag->ofs > this->ofs) {
 199                 /* This node isn't completely obsoleted. The start of it remains valid */
 200
 201                 /* Mark the new node and the partially covered node REF_NORMAL -- let
 202                    the GC take a look at them */
 203                 mark_ref_normal(newfrag->node->raw);
 204                 if (this->node)
 205                         mark_ref_normal(this->node->raw);
 206
 207                 if (this->ofs + this->size > newfrag->ofs + newfrag->size) {
 208                         /* The new node splits 'this' frag into two */
 209                         struct jffs2_node_frag *newfrag2 = jffs2_alloc_node_frag();
 210                         if (!newfrag2) {
 211                                 jffs2_free_node_frag(newfrag);
 212                                 return -ENOMEM;
 213                         }
 214                         if (this->node)
 215                                 JFFS2_DBG_FRAGTREE2("split old frag 0x%04x-0x%04x, phys 0x%08x\n",
 216                                         this->ofs, this->ofs+this->size, ref_offset(this->node->raw));
 217                         else
 218                                 JFFS2_DBG_FRAGTREE2("split old hole frag 0x%04x-0x%04x\n",
 219                                         this->ofs, this->ofs+this->size, ref_offset(this->node->raw));
 220
 221                         /* New second frag pointing to this's node */
 222                         newfrag2->ofs = newfrag->ofs + newfrag->size;
 223                         newfrag2->size = (this->ofs+this->size) - newfrag2->ofs;
 224                         newfrag2->node = this->node;
 225                         if (this->node)
 226                                 this->node->frags++;
 227
 228                         /* Adjust size of original 'this' */
 229                         this->size = newfrag->ofs - this->ofs;
 230
 231                         /* Now, we know there's no node with offset
 232                            greater than this->ofs but smaller than
 233                            newfrag2->ofs or newfrag->ofs, for obvious
 234                            reasons. So we can do a tree insert from
 235                            'this' to insert newfrag, and a tree insert
 236                            from newfrag to insert newfrag2. */
 237                         jffs2_fragtree_insert(newfrag, this);
 238                         rb_insert_color(&newfrag->rb, list);
 239
 240                         jffs2_fragtree_insert(newfrag2, newfrag);
 241                         rb_insert_color(&newfrag2->rb, list);
 242
 243                         return 0;
 244                 }
 245                 /* New node just reduces 'this' frag in size, doesn't split it */
 246                 this->size = newfrag->ofs - this->ofs;
 247
 248                 /* Again, we know it lives down here in the tree */
 249                 jffs2_fragtree_insert(newfrag, this);
 250                 rb_insert_color(&newfrag->rb, list);
 251         } else {
 252                 /* New frag starts at the same point as 'this' used to. Replace
 253                    it in the tree without doing a delete and insertion */
 254                 JFFS2_DBG_FRAGTREE2("inserting newfrag (*%p),%d-%d in before 'this' (*%p),%d-%d\n",
 255                           newfrag, newfrag->ofs, newfrag->ofs+newfrag->size, this, this->ofs, this->ofs+this->size);
 256
 257                 rb_replace_node(&this->rb, &newfrag->rb, list);
 258
 259                 if (newfrag->ofs + newfrag->size >= this->ofs+this->size) {
 260                         JFFS2_DBG_FRAGTREE2("obsoleting node frag %p (%x-%x)\n", this, this->ofs, this->ofs+this->size);
 261                         jffs2_obsolete_node_frag(c, this);
 262                 } else {
 263                         this->ofs += newfrag->size;
 264                         this->size -= newfrag->size;
 265
 266                         jffs2_fragtree_insert(this, newfrag);
 267                         rb_insert_color(&this->rb, list);
 268                         return 0;
 269                 }
 270         }
 271         /* OK, now we have newfrag added in the correct place in the tree, but
 272            frag_next(newfrag) may be a fragment which is overlapped by it
 273         */
 274         while ((this = frag_next(newfrag)) && newfrag->ofs + newfrag->size >= this->ofs + this->size) {
 275                 /* 'this' frag is obsoleted completely. */
 276                 JFFS2_DBG_FRAGTREE2("obsoleting node frag %p (%x-%x) and removing from tree\n",
 277                         this, this->ofs, this->ofs+this->size);
 278                 rb_erase(&this->rb, list);
 279                 jffs2_obsolete_node_frag(c, this);
 280         }
 281         /* Now we're pointing at the first frag which isn't totally obsoleted by
 282            the new frag */
 283
 284         if (!this || newfrag->ofs + newfrag->size == this->ofs) {
 285                 return 0;
 286         }
 287         /* Still some overlap but we don't need to move it in the tree */
 288         this->size = (this->ofs + this->size) - (newfrag->ofs + newfrag->size);
 289         this->ofs = newfrag->ofs + newfrag->size;
 290
 291         /* And mark them REF_NORMAL so the GC takes a look at them */
 292         if (this->node)
 293                 mark_ref_normal(this->node->raw);
 294         mark_ref_normal(newfrag->node->raw);
 295
 296         return 0;
 297 }
 298
 299 /* Given an inode, probably with existing list of fragments, add the new node
 300  * to the fragment list.
 301  */
 302 int jffs2_add_full_dnode_to_inode(struct jffs2_sb_info *c, struct jffs2_inode_info *f, struct jffs2_full_dnode *fn)
 303 {
 304         int ret;
 305         struct jffs2_node_frag *newfrag;
 306
 307         if (unlikely(!fn->size))
 308                 return 0;
 309
 310         newfrag = jffs2_alloc_node_frag();
 311         if (unlikely(!newfrag))
 312                 return -ENOMEM;
 313
 314         JFFS2_DBG_FRAGTREE("adding node %#04x-%#04x @0x%08x on flash, newfrag *%p\n",
 315                   fn->ofs, fn->ofs+fn->size, ref_offset(fn->raw), newfrag);
 316
 317         newfrag->ofs = fn->ofs;
 318         newfrag->size = fn->size;
 319         newfrag->node = fn;
 320         newfrag->node->frags = 1;
 321
 322         ret = jffs2_add_frag_to_fragtree(c, &f->fragtree, newfrag);
 323         if (unlikely(ret))
 324                 return ret;
 325
 326         /* If we now share a page with other nodes, mark either previous
 327            or next node REF_NORMAL, as appropriate.  */
 328         if (newfrag->ofs & (PAGE_CACHE_SIZE-1)) {
 329                 struct jffs2_node_frag *prev = frag_prev(newfrag);
 330
 331                 mark_ref_normal(fn->raw);
 332                 /* If we don't start at zero there's _always_ a previous */
 333                 if (prev->node)
 334                         mark_ref_normal(prev->node->raw);
 335         }
 336
 337         if ((newfrag->ofs+newfrag->size) & (PAGE_CACHE_SIZE-1)) {
 338                 struct jffs2_node_frag *next = frag_next(newfrag);
 339
 340                 if (next) {
 341                         mark_ref_normal(fn->raw);
 342                         if (next->node)
 343                                 mark_ref_normal(next->node->raw);
 344                 }
 345         }
 346         jffs2_dbg_fragtree_paranoia_check_nolock(f);
 347         jffs2_dbg_dump_fragtree_nolock(f);
 348         return 0;
 349 }
 350
 351
 352 void jffs2_set_inocache_state(struct jffs2_sb_info *c, struct jffs2_inode_cache *ic, int state)
 353 {
 354         spin_lock(&c->inocache_lock);
 355         ic->state = state;
 356         wake_up(&c->inocache_wq);
 357         spin_unlock(&c->inocache_lock);
 358 }
 359
 360 /* During mount, this needs no locking. During normal operation, its
 361    callers want to do other stuff while still holding the inocache_lock.
 362    Rather than introducing special case get_ino_cache functions or
 363    callbacks, we just let the caller do the locking itself. */
 364
 365 struct jffs2_inode_cache *jffs2_get_ino_cache(struct jffs2_sb_info *c, uint32_t ino)
 366 {
 367         struct jffs2_inode_cache *ret;
 368
 369         ret = c->inocache_list[ino % INOCACHE_HASHSIZE];
 370         while (ret && ret->ino < ino) {
 371                 ret = ret->next;
 372         }
 373
 374         if (ret && ret->ino != ino)
 375                 ret = NULL;
 376
 377         return ret;
 378 }
 379
 380 void jffs2_add_ino_cache (struct jffs2_sb_info *c, struct jffs2_inode_cache *new)
 381 {
 382         struct jffs2_inode_cache **prev;
 383
 384         spin_lock(&c->inocache_lock);
 385         if (!new->ino)
 386                 new->ino = ++c->highest_ino;
 387
 388         JFFS2_DBG_INOCACHE("add %p (ino #%u)\n", new, new->ino);
 389
 390         prev = &c->inocache_list[new->ino % INOCACHE_HASHSIZE];
 391
 392         while ((*prev) && (*prev)->ino < new->ino) {
 393                 prev = &(*prev)->next;
 394         }
 395         new->next = *prev;
 396         *prev = new;
 397
 398         spin_unlock(&c->inocache_lock);
 399 }
 400
 401 void jffs2_del_ino_cache(struct jffs2_sb_info *c, struct jffs2_inode_cache *old)
 402 {
 403         struct jffs2_inode_cache **prev;
 404
 405         JFFS2_DBG_INOCACHE("del %p (ino #%u)\n", old, old->ino);
 406         spin_lock(&c->inocache_lock);
 407
 408         prev = &c->inocache_list[old->ino % INOCACHE_HASHSIZE];
 409
 410         while ((*prev) && (*prev)->ino < old->ino) {
 411                 prev = &(*prev)->next;
 412         }
 413         if ((*prev) == old) {
 414                 *prev = old->next;
 415         }
 416
 417         /* Free it now unless it's in READING or CLEARING state, which
 418            are the transitions upon read_inode() and clear_inode(). The
 419            rest of the time we know nobody else is looking at it, and
 420            if it's held by read_inode() or clear_inode() they'll free it
 421            for themselves. */
 422         if (old->state != INO_STATE_READING && old->state != INO_STATE_CLEARING)
 423                 jffs2_free_inode_cache(old);
 424
 425         spin_unlock(&c->inocache_lock);
 426 }
 427
 428 void jffs2_free_ino_caches(struct jffs2_sb_info *c)
 429 {
 430         int i;
 431         struct jffs2_inode_cache *this, *next;
 432
 433         for (i=0; i<INOCACHE_HASHSIZE; i++) {
 434                 this = c->inocache_list[i];
 435                 while (this) {
 436                         next = this->next;
 437                         jffs2_free_inode_cache(this);
 438                         this = next;
 439                 }
 440                 c->inocache_list[i] = NULL;
 441         }
 442 }
 443
 444 void jffs2_free_raw_node_refs(struct jffs2_sb_info *c)
 445 {
 446         int i;
 447         struct jffs2_raw_node_ref *this, *next;
 448
 449         for (i=0; i<c->nr_blocks; i++) {
 450                 this = c->blocks[i].first_node;
 451                 while(this) {
 452                         next = this->next_phys;
 453                         jffs2_free_raw_node_ref(this);
 454                         this = next;
 455                 }
 456                 c->blocks[i].first_node = c->blocks[i].last_node = NULL;
 457         }
 458 }
 459
 460 struct jffs2_node_frag *jffs2_lookup_node_frag(struct rb_root *fragtree, uint32_t offset)
 461 {
 462         /* The common case in lookup is that there will be a node
 463            which precisely matches. So we go looking for that first */
 464         struct rb_node *next;
 465         struct jffs2_node_frag *prev = NULL;
 466         struct jffs2_node_frag *frag = NULL;
 467
 468         JFFS2_DBG_FRAGTREE2("root %p, offset %d\n", fragtree, offset);
 469
 470         next = fragtree->rb_node;
 471
 472         while(next) {
 473                 frag = rb_entry(next, struct jffs2_node_frag, rb);
 474
 475                 JFFS2_DBG_FRAGTREE2("considering frag %#04x-%#04x (%p). left %p, right %p\n",
 476                           frag->ofs, frag->ofs+frag->size, frag, frag->rb.rb_left, frag->rb.rb_right);
 477                 if (frag->ofs + frag->size <= offset) {
 478                         JFFS2_DBG_FRAGTREE2("going right from frag %#04x-%#04x, before the region we care about\n",
 479                                   frag->ofs, frag->ofs+frag->size);
 480                         /* Remember the closest smaller match on the way down */
 481                         if (!prev || frag->ofs > prev->ofs)
 482                                 prev = frag;
 483                         next = frag->rb.rb_right;
 484                 } else if (frag->ofs > offset) {
 485                         JFFS2_DBG_FRAGTREE2("going left from frag %#04x-%#04x, after the region we care about\n",
 486                                   frag->ofs, frag->ofs+frag->size);
 487                         next = frag->rb.rb_left;
 488                 } else {
 489                         JFFS2_DBG_FRAGTREE2("returning frag %#04x-%#04x, matched\n",
 490                                   frag->ofs, frag->ofs+frag->size);
 491                         return frag;
 492                 }
 493         }
 494
 495         /* Exact match not found. Go back up looking at each parent,
 496            and return the closest smaller one */
 497
 498         if (prev)
 499                 JFFS2_DBG_FRAGTREE2("no match. Returning frag %#04x-%#04x, closest previous\n",
 500                           prev->ofs, prev->ofs+prev->size);
 501         else
 502                 JFFS2_DBG_FRAGTREE2("returning NULL, empty fragtree\n");
 503
 504         return prev;
 505 }
 506
 507 /* Pass 'c' argument to indicate that nodes should be marked obsolete as
 508    they're killed. */
 509 void jffs2_kill_fragtree(struct rb_root *root, struct jffs2_sb_info *c)
 510 {
 511         struct jffs2_node_frag *frag;
 512         struct jffs2_node_frag *parent;
 513
 514         if (!root->rb_node)
 515                 return;
 516
 517         JFFS2_DBG_FRAGTREE("killing\n");
 518
 519         frag = (rb_entry(root->rb_node, struct jffs2_node_frag, rb));
 520         while(frag) {
 521                 if (frag->rb.rb_left) {
 522                         JFFS2_DBG_FRAGTREE2("going left from frag (%p) %#04x-%#04x\n",
 523                                 frag, frag->ofs, frag->ofs+frag->size);
 524                         frag = frag_left(frag);
 525                         continue;
 526                 }
 527                 if (frag->rb.rb_right) {
 528                         JFFS2_DBG_FRAGTREE2("going right from frag (%p) %#04x-%#04x\n",
 529                                   frag, frag->ofs, frag->ofs+frag->size);
 530                         frag = frag_right(frag);
 531                         continue;
 532                 }
 533
 534                 JFFS2_DBG_FRAGTREE2("frag %#04x-%#04x: node %p, frags %d\n",
 535                           frag->ofs, frag->ofs+frag->size, frag->node, frag->node?frag->node->frags:0);
 536
 537                 if (frag->node && !(--frag->node->frags)) {
 538                         /* Not a hole, and it's the final remaining frag
 539                            of this node. Free the node */
 540                         if (c)
 541                                 jffs2_mark_node_obsolete(c, frag->node->raw);
 542
 543                         jffs2_free_full_dnode(frag->node);
 544                 }
 545                 parent = frag_parent(frag);
 546                 if (parent) {
 547                         if (frag_left(parent) == frag)
 548                                 parent->rb.rb_left = NULL;
 549                         else
 550                                 parent->rb.rb_right = NULL;
 551                 }
 552
 553                 jffs2_free_node_frag(frag);
 554                 frag = parent;
 555
 556                 cond_resched();
 557         }
 558 }