packages/fs/jffs2/v2_0/src/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  * $Id$
  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 Marking new dirent node is obsolete, old is \"%s\", ino #%u\n",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_obsolete_node_frag(struct jffs2_sb_info *c, struct jffs2_node_frag *this)
  55 {
  56         if (this->node) {
  57                 this->node->frags--;
  58                 if (!this->node->frags) {
  59                         /* The node has no valid frags left. It's totally obsoleted */
  60                         JFFS2_DBG_FRAGTREE2("marking old node @0x%08x (0x%04x-0x%04x) obsolete\n",
  61                                 ref_offset(this->node->raw), this->node->ofs, this->node->ofs+this->node->size);
  62                         jffs2_mark_node_obsolete(c, this->node->raw);
  63                         jffs2_free_full_dnode(this->node);
  64                 } else {
  65                         JFFS2_DBG_FRAGTREE2("marking old node @0x%08x (0x%04x-0x%04x) REF_NORMAL. frags is %d\n",
  66                                 ref_offset(this->node->raw), this->node->ofs, this->node->ofs+this->node->size, this->node->frags);
  67                         mark_ref_normal(this->node->raw);
  68                 }
  69
  70         }
  71         jffs2_free_node_frag(this);
  72 }
  73
  74 static void jffs2_fragtree_insert(struct jffs2_node_frag *newfrag, struct jffs2_node_frag *base)
  75 {
  76         struct rb_node *parent = &base->rb;
  77         struct rb_node **link = &parent;
  78
  79         JFFS2_DBG_FRAGTREE2("insert frag (0x%04x-0x%04x)\n", newfrag->ofs, newfrag->ofs + newfrag->size);
  80
  81         while (*link) {
  82                 parent = *link;
  83                 base = rb_entry(parent, struct jffs2_node_frag, rb);
  84
  85                 JFFS2_DBG_FRAGTREE2("considering frag at 0x%08x\n", base->ofs);
  86                 if (newfrag->ofs > base->ofs)
  87                         link = &base->rb.rb_right;
  88                 else if (newfrag->ofs < base->ofs)
  89                         link = &base->rb.rb_left;
  90                 else {
  91                         JFFS2_ERROR("duplicate frag at %08x (%p,%p)\n", newfrag->ofs, newfrag, base);
  92                         BUG();
  93                 }
  94         }
  95
  96         rb_link_node(&newfrag->rb, &base->rb, link);
  97 }
  98
  99 /* Doesn't set inode->i_size */
 100 static int jffs2_add_frag_to_fragtree(struct jffs2_sb_info *c, struct rb_root *list, struct jffs2_node_frag *newfrag)
 101 {
 102         struct jffs2_node_frag *this;
 103         uint32_t lastend;
 104
 105         /* Skip all the nodes which are completed before this one starts */
 106         this = jffs2_lookup_node_frag(list, newfrag->node->ofs);
 107
 108         if (this) {
 109                 JFFS2_DBG_FRAGTREE2("lookup gave frag 0x%04x-0x%04x; phys 0x%08x (*%p)\n",
 110                           this->ofs, this->ofs+this->size, this->node?(ref_offset(this->node->raw)):0xffffffff, this);
 111                 lastend = this->ofs + this->size;
 112         } else {
 113                 JFFS2_DBG_FRAGTREE2("lookup gave no frag\n");
 114                 lastend = 0;
 115         }
 116
 117         /* See if we ran off the end of the list */
 118         if (lastend <= newfrag->ofs) {
 119                 /* We did */
 120
 121                 /* Check if 'this' node was on the same page as the new node.
 122                    If so, both 'this' and the new node get marked REF_NORMAL so
 123                    the GC can take a look.
 124                 */
 125                 if (lastend && (lastend-1) >> PAGE_CACHE_SHIFT == newfrag->ofs >> PAGE_CACHE_SHIFT) {
 126                         if (this->node)
 127                                 mark_ref_normal(this->node->raw);
 128                         mark_ref_normal(newfrag->node->raw);
 129                 }
 130
 131                 if (lastend < newfrag->node->ofs) {
 132                         /* ... and we need to put a hole in before the new node */
 133                         struct jffs2_node_frag *holefrag = jffs2_alloc_node_frag();
 134                         if (!holefrag) {
 135                                 jffs2_free_node_frag(newfrag);
 136                                 return -ENOMEM;
 137                         }
 138                         holefrag->ofs = lastend;
 139                         holefrag->size = newfrag->node->ofs - lastend;
 140                         holefrag->node = NULL;
 141                         if (this) {
 142                                 /* By definition, the 'this' node has no right-hand child,
 143                                    because there are no frags with offset greater than it.
 144                                    So that's where we want to put the hole */
 145                                 JFFS2_DBG_FRAGTREE2("adding hole frag (%p) on right of node at (%p)\n", holefrag, this);
 146                                 rb_link_node(&holefrag->rb, &this->rb, &this->rb.rb_right);
 147                         } else {
 148                                 JFFS2_DBG_FRAGTREE2("adding hole frag (%p) at root of tree\n", holefrag);
 149                                 rb_link_node(&holefrag->rb, NULL, &list->rb_node);
 150                         }
 151                         rb_insert_color(&holefrag->rb, list);
 152                         this = holefrag;
 153                 }
 154                 if (this) {
 155                         /* By definition, the 'this' node has no right-hand child,
 156                            because there are no frags with offset greater than it.
 157                            So that's where we want to put new fragment */
 158                         JFFS2_DBG_FRAGTREE2("adding new frag (%p) on right of node at (%p)\n", newfrag, this);
 159                         rb_link_node(&newfrag->rb, &this->rb, &this->rb.rb_right);
 160                 } else {
 161                         JFFS2_DBG_FRAGTREE2("adding new frag (%p) at root of tree\n", newfrag);
 162                         rb_link_node(&newfrag->rb, NULL, &list->rb_node);
 163                 }
 164                 rb_insert_color(&newfrag->rb, list);
 165                 return 0;
 166         }
 167
 168         JFFS2_DBG_FRAGTREE2("dealing with frag 0x%04x-0x%04x; phys 0x%08x (*%p)\n",
 169                   this->ofs, this->ofs+this->size, this->node?(ref_offset(this->node->raw)):0xffffffff, this);
 170
 171         /* OK. 'this' is pointing at the first frag that newfrag->ofs at least partially obsoletes,
 172          * - i.e. newfrag->ofs < this->ofs+this->size && newfrag->ofs >= this->ofs
 173          */
 174         if (newfrag->ofs > this->ofs) {
 175                 /* This node isn't completely obsoleted. The start of it remains valid */
 176
 177                 /* Mark the new node and the partially covered node REF_NORMAL -- let
 178                    the GC take a look at them */
 179                 mark_ref_normal(newfrag->node->raw);
 180                 if (this->node)
 181                         mark_ref_normal(this->node->raw);
 182
 183                 if (this->ofs + this->size > newfrag->ofs + newfrag->size) {
 184                         /* The new node splits 'this' frag into two */
 185                         struct jffs2_node_frag *newfrag2 = jffs2_alloc_node_frag();
 186                         if (!newfrag2) {
 187                                 jffs2_free_node_frag(newfrag);
 188                                 return -ENOMEM;
 189                         }
 190                         if (this->node)
 191                                 JFFS2_DBG_FRAGTREE2("split old frag 0x%04x-0x%04x, phys 0x%08x\n",
 192                                         this->ofs, this->ofs+this->size, ref_offset(this->node->raw));
 193                         else
 194                                 JFFS2_DBG_FRAGTREE2("split old hole frag 0x%04x-0x%04x\n",
 195                                         this->ofs, this->ofs+this->size, ref_offset(this->node->raw));
 196
 197                         /* New second frag pointing to this's node */
 198                         newfrag2->ofs = newfrag->ofs + newfrag->size;
 199                         newfrag2->size = (this->ofs+this->size) - newfrag2->ofs;
 200                         newfrag2->node = this->node;
 201                         if (this->node)
 202                                 this->node->frags++;
 203
 204                         /* Adjust size of original 'this' */
 205                         this->size = newfrag->ofs - this->ofs;
 206
 207                         /* Now, we know there's no node with offset
 208                            greater than this->ofs but smaller than
 209                            newfrag2->ofs or newfrag->ofs, for obvious
 210                            reasons. So we can do a tree insert from
 211                            'this' to insert newfrag, and a tree insert
 212                            from newfrag to insert newfrag2. */
 213                         jffs2_fragtree_insert(newfrag, this);
 214                         rb_insert_color(&newfrag->rb, list);
 215
 216                         jffs2_fragtree_insert(newfrag2, newfrag);
 217                         rb_insert_color(&newfrag2->rb, list);
 218
 219                         return 0;
 220                 }
 221                 /* New node just reduces 'this' frag in size, doesn't split it */
 222                 this->size = newfrag->ofs - this->ofs;
 223
 224                 /* Again, we know it lives down here in the tree */
 225                 jffs2_fragtree_insert(newfrag, this);
 226                 rb_insert_color(&newfrag->rb, list);
 227         } else {
 228                 /* New frag starts at the same point as 'this' used to. Replace
 229                    it in the tree without doing a delete and insertion */
 230                 JFFS2_DBG_FRAGTREE2("inserting newfrag (*%p),%d-%d in before 'this' (*%p),%d-%d\n",
 231                           newfrag, newfrag->ofs, newfrag->ofs+newfrag->size, this, this->ofs, this->ofs+this->size);
 232
 233                 rb_replace_node(&this->rb, &newfrag->rb, list);
 234
 235                 if (newfrag->ofs + newfrag->size >= this->ofs+this->size) {
 236                         JFFS2_DBG_FRAGTREE2("obsoleting node frag %p (%x-%x)\n", this, this->ofs, this->ofs+this->size);
 237                         jffs2_obsolete_node_frag(c, this);
 238                 } else {
 239                         this->ofs += newfrag->size;
 240                         this->size -= newfrag->size;
 241
 242                         jffs2_fragtree_insert(this, newfrag);
 243                         rb_insert_color(&this->rb, list);
 244                         return 0;
 245                 }
 246         }
 247         /* OK, now we have newfrag added in the correct place in the tree, but
 248            frag_next(newfrag) may be a fragment which is overlapped by it
 249         */
 250         while ((this = frag_next(newfrag)) && newfrag->ofs + newfrag->size >= this->ofs + this->size) {
 251                 /* 'this' frag is obsoleted completely. */
 252                 JFFS2_DBG_FRAGTREE2("obsoleting node frag %p (%x-%x) and removing from tree\n",
 253                         this, this->ofs, this->ofs+this->size);
 254                 rb_erase(&this->rb, list);
 255                 jffs2_obsolete_node_frag(c, this);
 256         }
 257         /* Now we're pointing at the first frag which isn't totally obsoleted by
 258            the new frag */
 259
 260         if (!this || newfrag->ofs + newfrag->size == this->ofs) {
 261                 return 0;
 262         }
 263         /* Still some overlap but we don't need to move it in the tree */
 264         this->size = (this->ofs + this->size) - (newfrag->ofs + newfrag->size);
 265         this->ofs = newfrag->ofs + newfrag->size;
 266
 267         /* And mark them REF_NORMAL so the GC takes a look at them */
 268         if (this->node)
 269                 mark_ref_normal(this->node->raw);
 270         mark_ref_normal(newfrag->node->raw);
 271
 272         return 0;
 273 }
 274
 275 /* Given an inode, probably with existing list of fragments, add the new node
 276  * to the fragment list.
 277  */
 278 int jffs2_add_full_dnode_to_inode(struct jffs2_sb_info *c, struct jffs2_inode_info *f, struct jffs2_full_dnode *fn)
 279 {
 280         int ret;
 281         struct jffs2_node_frag *newfrag;
 282
 283         if (unlikely(!fn->size))
 284                 return 0;
 285
 286         newfrag = jffs2_alloc_node_frag();
 287         if (unlikely(!newfrag))
 288                 return -ENOMEM;
 289
 290         JFFS2_DBG_FRAGTREE("adding node %#04x-%#04x @0x%08x on flash, newfrag *%p\n",
 291                   fn->ofs, fn->ofs+fn->size, ref_offset(fn->raw), newfrag);
 292
 293         newfrag->ofs = fn->ofs;
 294         newfrag->size = fn->size;
 295         newfrag->node = fn;
 296         newfrag->node->frags = 1;
 297
 298         ret = jffs2_add_frag_to_fragtree(c, &f->fragtree, newfrag);
 299         if (unlikely(ret))
 300                 return ret;
 301
 302         /* If we now share a page with other nodes, mark either previous
 303            or next node REF_NORMAL, as appropriate.  */
 304         if (newfrag->ofs & (PAGE_CACHE_SIZE-1)) {
 305                 struct jffs2_node_frag *prev = frag_prev(newfrag);
 306
 307                 mark_ref_normal(fn->raw);
 308                 /* If we don't start at zero there's _always_ a previous */
 309                 if (prev->node)
 310                         mark_ref_normal(prev->node->raw);
 311         }
 312
 313         if ((newfrag->ofs+newfrag->size) & (PAGE_CACHE_SIZE-1)) {
 314                 struct jffs2_node_frag *next = frag_next(newfrag);
 315
 316                 if (next) {
 317                         mark_ref_normal(fn->raw);
 318                         if (next->node)
 319                                 mark_ref_normal(next->node->raw);
 320                 }
 321         }
 322         jffs2_dbg_fragtree_paranoia_check_nolock(f);
 323         jffs2_dbg_dump_fragtree_nolock(f);
 324         return 0;
 325 }
 326
 327
 328 void jffs2_set_inocache_state(struct jffs2_sb_info *c, struct jffs2_inode_cache *ic, int state)
 329 {
 330         spin_lock(&c->inocache_lock);
 331         ic->state = state;
 332         wake_up(&c->inocache_wq);
 333         spin_unlock(&c->inocache_lock);
 334 }
 335
 336 /* During mount, this needs no locking. During normal operation, its
 337    callers want to do other stuff while still holding the inocache_lock.
 338    Rather than introducing special case get_ino_cache functions or
 339    callbacks, we just let the caller do the locking itself. */
 340
 341 struct jffs2_inode_cache *jffs2_get_ino_cache(struct jffs2_sb_info *c, uint32_t ino)
 342 {
 343         struct jffs2_inode_cache *ret;
 344
 345         ret = c->inocache_list[ino % INOCACHE_HASHSIZE];
 346         while (ret && ret->ino < ino) {
 347                 ret = ret->next;
 348         }
 349
 350         if (ret && ret->ino != ino)
 351                 ret = NULL;
 352
 353         return ret;
 354 }
 355
 356 void jffs2_add_ino_cache (struct jffs2_sb_info *c, struct jffs2_inode_cache *new)
 357 {
 358         struct jffs2_inode_cache **prev;
 359
 360         spin_lock(&c->inocache_lock);
 361         if (!new->ino)
 362                 new->ino = ++c->highest_ino;
 363
 364         JFFS2_DBG_INOCACHE("add %p (ino #%u)\n", new, new->ino);
 365
 366         prev = &c->inocache_list[new->ino % INOCACHE_HASHSIZE];
 367
 368         while ((*prev) && (*prev)->ino < new->ino) {
 369                 prev = &(*prev)->next;
 370         }
 371         new->next = *prev;
 372         *prev = new;
 373
 374         spin_unlock(&c->inocache_lock);
 375 }
 376
 377 void jffs2_del_ino_cache(struct jffs2_sb_info *c, struct jffs2_inode_cache *old)
 378 {
 379         struct jffs2_inode_cache **prev;
 380
 381         JFFS2_DBG_INOCACHE("del %p (ino #%u)\n", old, old->ino);
 382         spin_lock(&c->inocache_lock);
 383
 384         prev = &c->inocache_list[old->ino % INOCACHE_HASHSIZE];
 385
 386         while ((*prev) && (*prev)->ino < old->ino) {
 387                 prev = &(*prev)->next;
 388         }
 389         if ((*prev) == old) {
 390                 *prev = old->next;
 391         }
 392
 393         /* Free it now unless it's in READING or CLEARING state, which
 394            are the transitions upon read_inode() and clear_inode(). The
 395            rest of the time we know nobody else is looking at it, and
 396            if it's held by read_inode() or clear_inode() they'll free it
 397            for themselves. */
 398         if (old->state != INO_STATE_READING && old->state != INO_STATE_CLEARING)
 399                 jffs2_free_inode_cache(old);
 400
 401         spin_unlock(&c->inocache_lock);
 402 }
 403
 404 void jffs2_free_ino_caches(struct jffs2_sb_info *c)
 405 {
 406         int i;
 407         struct jffs2_inode_cache *this, *next;
 408
 409         for (i=0; i<INOCACHE_HASHSIZE; i++) {
 410                 this = c->inocache_list[i];
 411                 while (this) {
 412                         next = this->next;
 413                         jffs2_free_inode_cache(this);
 414                         this = next;
 415                 }
 416                 c->inocache_list[i] = NULL;
 417         }
 418 }
 419
 420 void jffs2_free_raw_node_refs(struct jffs2_sb_info *c)
 421 {
 422         int i;
 423         struct jffs2_raw_node_ref *this, *next;
 424
 425         for (i=0; i<c->nr_blocks; i++) {
 426                 this = c->blocks[i].first_node;
 427                 while(this) {
 428                         next = this->next_phys;
 429                         jffs2_free_raw_node_ref(this);
 430                         this = next;
 431                 }
 432                 c->blocks[i].first_node = c->blocks[i].last_node = NULL;
 433         }
 434 }
 435
 436 struct jffs2_node_frag *jffs2_lookup_node_frag(struct rb_root *fragtree, uint32_t offset)
 437 {
 438         /* The common case in lookup is that there will be a node
 439            which precisely matches. So we go looking for that first */
 440         struct rb_node *next;
 441         struct jffs2_node_frag *prev = NULL;
 442         struct jffs2_node_frag *frag = NULL;
 443
 444         JFFS2_DBG_FRAGTREE2("root %p, offset %d\n", fragtree, offset);
 445
 446         next = fragtree->rb_node;
 447
 448         while(next) {
 449                 frag = rb_entry(next, struct jffs2_node_frag, rb);
 450
 451                 JFFS2_DBG_FRAGTREE2("considering frag %#04x-%#04x (%p). left %p, right %p\n",
 452                           frag->ofs, frag->ofs+frag->size, frag, frag->rb.rb_left, frag->rb.rb_right);
 453                 if (frag->ofs + frag->size <= offset) {
 454                         JFFS2_DBG_FRAGTREE2("going right from frag %#04x-%#04x, before the region we care about\n",
 455                                   frag->ofs, frag->ofs+frag->size);
 456                         /* Remember the closest smaller match on the way down */
 457                         if (!prev || frag->ofs > prev->ofs)
 458                                 prev = frag;
 459                         next = frag->rb.rb_right;
 460                 } else if (frag->ofs > offset) {
 461                         JFFS2_DBG_FRAGTREE2("going left from frag %#04x-%#04x, after the region we care about\n",
 462                                   frag->ofs, frag->ofs+frag->size);
 463                         next = frag->rb.rb_left;
 464                 } else {
 465                         JFFS2_DBG_FRAGTREE2("returning frag %#04x-%#04x, matched\n",
 466                                   frag->ofs, frag->ofs+frag->size);
 467                         return frag;
 468                 }
 469         }
 470
 471         /* Exact match not found. Go back up looking at each parent,
 472            and return the closest smaller one */
 473
 474         if (prev)
 475                 JFFS2_DBG_FRAGTREE2("no match. Returning frag %#04x-%#04x, closest previous\n",
 476                           prev->ofs, prev->ofs+prev->size);
 477         else
 478                 JFFS2_DBG_FRAGTREE2("returning NULL, empty fragtree\n");
 479
 480         return prev;
 481 }
 482
 483 /* Pass 'c' argument to indicate that nodes should be marked obsolete as
 484    they're killed. */
 485 void jffs2_kill_fragtree(struct rb_root *root, struct jffs2_sb_info *c)
 486 {
 487         struct jffs2_node_frag *frag;
 488         struct jffs2_node_frag *parent;
 489
 490         if (!root->rb_node)
 491                 return;
 492
 493         JFFS2_DBG_FRAGTREE("killing\n");
 494
 495         frag = (rb_entry(root->rb_node, struct jffs2_node_frag, rb));
 496         while(frag) {
 497                 if (frag->rb.rb_left) {
 498                         JFFS2_DBG_FRAGTREE2("going left from frag (%p) %#04x-%#04x\n",
 499                                 frag, frag->ofs, frag->ofs+frag->size);
 500                         frag = frag_left(frag);
 501                         continue;
 502                 }
 503                 if (frag->rb.rb_right) {
 504                         JFFS2_DBG_FRAGTREE2("going right from frag (%p) %#04x-%#04x\n",
 505                                   frag, frag->ofs, frag->ofs+frag->size);
 506                         frag = frag_right(frag);
 507                         continue;
 508                 }
 509
 510                 JFFS2_DBG_FRAGTREE2("frag %#04x-%#04x: node %p, frags %d\n",
 511                           frag->ofs, frag->ofs+frag->size, frag->node, frag->node?frag->node->frags:0);
 512
 513                 if (frag->node && !(--frag->node->frags)) {
 514                         /* Not a hole, and it's the final remaining frag
 515                            of this node. Free the node */
 516                         if (c)
 517                                 jffs2_mark_node_obsolete(c, frag->node->raw);
 518
 519                         jffs2_free_full_dnode(frag->node);
 520                 }
 521                 parent = frag_parent(frag);
 522                 if (parent) {
 523                         if (frag_left(parent) == frag)
 524                                 parent->rb.rb_left = NULL;
 525                         else
 526                                 parent->rb.rb_right = NULL;
 527                 }
 528
 529                 jffs2_free_node_frag(frag);
 530                 frag = parent;
 531
 532                 cond_resched();
 533         }
 534 }