git.oblomov.eu Git - linux-2.6/blob - 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 1.101 2005/07/27 14:46:11 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         D1(printk(KERN_DEBUG "jffs2_add_fd_to_list( %p, %p (->%p))\n", new, list, *list));
  28
  29         while ((*prev) && (*prev)->nhash <= new->nhash) {
  30                 if ((*prev)->nhash == new->nhash && !strcmp((*prev)->name, new->name)) {
  31                         /* Duplicate. Free one */
  32                         if (new->version < (*prev)->version) {
  33                                 D1(printk(KERN_DEBUG "Eep! Marking new dirent node obsolete\n"));
  34                                 D1(printk(KERN_DEBUG "New dirent is \"%s\"->ino #%u. Old is \"%s\"->ino #%u\n", new->name, new->ino, (*prev)->name, (*prev)->ino));
  35                                 jffs2_mark_node_obsolete(c, new->raw);
  36                                 jffs2_free_full_dirent(new);
  37                         } else {
  38                                 D1(printk(KERN_DEBUG "Marking old dirent node (ino #%u) obsolete\n", (*prev)->ino));
  39                                 new->next = (*prev)->next;
  40                                 jffs2_mark_node_obsolete(c, ((*prev)->raw));
  41                                 jffs2_free_full_dirent(*prev);
  42                                 *prev = new;
  43                         }
  44                         goto out;
  45                 }
  46                 prev = &((*prev)->next);
  47         }
  48         new->next = *prev;
  49         *prev = new;
  50
  51  out:
  52         D2(while(*list) {
  53                 printk(KERN_DEBUG "Dirent \"%s\" (hash 0x%08x, ino #%u\n", (*list)->name, (*list)->nhash, (*list)->ino);
  54                 list = &(*list)->next;
  55         });
  56 }
  57
  58 void jffs2_obsolete_node_frag(struct jffs2_sb_info *c, struct jffs2_node_frag *this)
  59 {
  60         if (this->node) {
  61                 this->node->frags--;
  62                 if (!this->node->frags) {
  63                         /* The node has no valid frags left. It's totally obsoleted */
  64                         D2(printk(KERN_DEBUG "Marking old node @0x%08x (0x%04x-0x%04x) obsolete\n",
  65                                   ref_offset(this->node->raw), this->node->ofs, this->node->ofs+this->node->size));
  66                         jffs2_mark_node_obsolete(c, this->node->raw);
  67                         jffs2_free_full_dnode(this->node);
  68                 } else {
  69                         D2(printk(KERN_DEBUG "Marking old node @0x%08x (0x%04x-0x%04x) REF_NORMAL. frags is %d\n",
  70                                   ref_offset(this->node->raw), this->node->ofs, this->node->ofs+this->node->size,
  71                                   this->node->frags));
  72                         mark_ref_normal(this->node->raw);
  73                 }
  74
  75         }
  76         jffs2_free_node_frag(this);
  77 }
  78
  79 static void jffs2_fragtree_insert(struct jffs2_node_frag *newfrag, struct jffs2_node_frag *base)
  80 {
  81         struct rb_node *parent = &base->rb;
  82         struct rb_node **link = &parent;
  83
  84         D2(printk(KERN_DEBUG "jffs2_fragtree_insert(%p; %d-%d, %p)\n", newfrag,
  85                   newfrag->ofs, newfrag->ofs+newfrag->size, base));
  86
  87         while (*link) {
  88                 parent = *link;
  89                 base = rb_entry(parent, struct jffs2_node_frag, rb);
  90
  91                 D2(printk(KERN_DEBUG "fragtree_insert considering frag at 0x%x\n", base->ofs));
  92                 if (newfrag->ofs > base->ofs)
  93                         link = &base->rb.rb_right;
  94                 else if (newfrag->ofs < base->ofs)
  95                         link = &base->rb.rb_left;
  96                 else {
  97                         printk(KERN_CRIT "Duplicate frag at %08x (%p,%p)\n", newfrag->ofs, newfrag, base);
  98                         BUG();
  99                 }
 100         }
 101
 102         rb_link_node(&newfrag->rb, &base->rb, link);
 103 }
 104
 105 /* Doesn't set inode->i_size */
 106 static int jffs2_add_frag_to_fragtree(struct jffs2_sb_info *c, struct rb_root *list, struct jffs2_node_frag *newfrag)
 107 {
 108         struct jffs2_node_frag *this;
 109         uint32_t lastend;
 110
 111         /* Skip all the nodes which are completed before this one starts */
 112         this = jffs2_lookup_node_frag(list, newfrag->node->ofs);
 113
 114         if (this) {
 115                 D2(printk(KERN_DEBUG "j_a_f_d_t_f: Lookup gave frag 0x%04x-0x%04x; phys 0x%08x (*%p)\n",
 116                           this->ofs, this->ofs+this->size, this->node?(ref_offset(this->node->raw)):0xffffffff, this));
 117                 lastend = this->ofs + this->size;
 118         } else {
 119                 D2(printk(KERN_DEBUG "j_a_f_d_t_f: Lookup gave no frag\n"));
 120                 lastend = 0;
 121         }
 122
 123         /* See if we ran off the end of the list */
 124         if (lastend <= newfrag->ofs) {
 125                 /* We did */
 126
 127                 /* Check if 'this' node was on the same page as the new node.
 128                    If so, both 'this' and the new node get marked REF_NORMAL so
 129                    the GC can take a look.
 130                 */
 131                 if (lastend && (lastend-1) >> PAGE_CACHE_SHIFT == newfrag->ofs >> PAGE_CACHE_SHIFT) {
 132                         if (this->node)
 133                                 mark_ref_normal(this->node->raw);
 134                         mark_ref_normal(newfrag->node->raw);
 135                 }
 136
 137                 if (lastend < newfrag->node->ofs) {
 138                         /* ... and we need to put a hole in before the new node */
 139                         struct jffs2_node_frag *holefrag = jffs2_alloc_node_frag();
 140                         if (!holefrag) {
 141                                 jffs2_free_node_frag(newfrag);
 142                                 return -ENOMEM;
 143                         }
 144                         holefrag->ofs = lastend;
 145                         holefrag->size = newfrag->node->ofs - lastend;
 146                         holefrag->node = NULL;
 147                         if (this) {
 148                                 /* By definition, the 'this' node has no right-hand child,
 149                                    because there are no frags with offset greater than it.
 150                                    So that's where we want to put the hole */
 151                                 D2(printk(KERN_DEBUG "Adding hole frag (%p) on right of node at (%p)\n", holefrag, this));
 152                                 rb_link_node(&holefrag->rb, &this->rb, &this->rb.rb_right);
 153                         } else {
 154                                 D2(printk(KERN_DEBUG "Adding hole frag (%p) at root of tree\n", holefrag));
 155                                 rb_link_node(&holefrag->rb, NULL, &list->rb_node);
 156                         }
 157                         rb_insert_color(&holefrag->rb, list);
 158                         this = holefrag;
 159                 }
 160                 if (this) {
 161                         /* By definition, the 'this' node has no right-hand child,
 162                            because there are no frags with offset greater than it.
 163                            So that's where we want to put new fragment */
 164                         D2(printk(KERN_DEBUG "Adding new frag (%p) on right of node at (%p)\n", newfrag, this));
 165                         rb_link_node(&newfrag->rb, &this->rb, &this->rb.rb_right);
 166                 } else {
 167                         D2(printk(KERN_DEBUG "Adding new frag (%p) at root of tree\n", newfrag));
 168                         rb_link_node(&newfrag->rb, NULL, &list->rb_node);
 169                 }
 170                 rb_insert_color(&newfrag->rb, list);
 171                 return 0;
 172         }
 173
 174         D2(printk(KERN_DEBUG "j_a_f_d_t_f: dealing with frag 0x%04x-0x%04x; phys 0x%08x (*%p)\n",
 175                   this->ofs, this->ofs+this->size, this->node?(ref_offset(this->node->raw)):0xffffffff, this));
 176
 177         /* OK. 'this' is pointing at the first frag that newfrag->ofs at least partially obsoletes,
 178          * - i.e. newfrag->ofs < this->ofs+this->size && newfrag->ofs >= this->ofs
 179          */
 180         if (newfrag->ofs > this->ofs) {
 181                 /* This node isn't completely obsoleted. The start of it remains valid */
 182
 183                 /* Mark the new node and the partially covered node REF_NORMAL -- let
 184                    the GC take a look at them */
 185                 mark_ref_normal(newfrag->node->raw);
 186                 if (this->node)
 187                         mark_ref_normal(this->node->raw);
 188
 189                 if (this->ofs + this->size > newfrag->ofs + newfrag->size) {
 190                         /* The new node splits 'this' frag into two */
 191                         struct jffs2_node_frag *newfrag2 = jffs2_alloc_node_frag();
 192                         if (!newfrag2) {
 193                                 jffs2_free_node_frag(newfrag);
 194                                 return -ENOMEM;
 195                         }
 196                         D2(printk(KERN_DEBUG "split old frag 0x%04x-0x%04x -->", this->ofs, this->ofs+this->size);
 197                         if (this->node)
 198                                 printk("phys 0x%08x\n", ref_offset(this->node->raw));
 199                         else
 200                                 printk("hole\n");
 201                            )
 202
 203                         /* New second frag pointing to this's node */
 204                         newfrag2->ofs = newfrag->ofs + newfrag->size;
 205                         newfrag2->size = (this->ofs+this->size) - newfrag2->ofs;
 206                         newfrag2->node = this->node;
 207                         if (this->node)
 208                                 this->node->frags++;
 209
 210                         /* Adjust size of original 'this' */
 211                         this->size = newfrag->ofs - this->ofs;
 212
 213                         /* Now, we know there's no node with offset
 214                            greater than this->ofs but smaller than
 215                            newfrag2->ofs or newfrag->ofs, for obvious
 216                            reasons. So we can do a tree insert from
 217                            'this' to insert newfrag, and a tree insert
 218                            from newfrag to insert newfrag2. */
 219                         jffs2_fragtree_insert(newfrag, this);
 220                         rb_insert_color(&newfrag->rb, list);
 221
 222                         jffs2_fragtree_insert(newfrag2, newfrag);
 223                         rb_insert_color(&newfrag2->rb, list);
 224
 225                         return 0;
 226                 }
 227                 /* New node just reduces 'this' frag in size, doesn't split it */
 228                 this->size = newfrag->ofs - this->ofs;
 229
 230                 /* Again, we know it lives down here in the tree */
 231                 jffs2_fragtree_insert(newfrag, this);
 232                 rb_insert_color(&newfrag->rb, list);
 233         } else {
 234                 /* New frag starts at the same point as 'this' used to. Replace
 235                    it in the tree without doing a delete and insertion */
 236                 D2(printk(KERN_DEBUG "Inserting newfrag (*%p),%d-%d in before 'this' (*%p),%d-%d\n",
 237                           newfrag, newfrag->ofs, newfrag->ofs+newfrag->size,
 238                           this, this->ofs, this->ofs+this->size));
 239
 240                 rb_replace_node(&this->rb, &newfrag->rb, list);
 241
 242                 if (newfrag->ofs + newfrag->size >= this->ofs+this->size) {
 243                         D2(printk(KERN_DEBUG "Obsoleting node frag %p (%x-%x)\n", this, this->ofs, this->ofs+this->size));
 244                         jffs2_obsolete_node_frag(c, this);
 245                 } else {
 246                         this->ofs += newfrag->size;
 247                         this->size -= newfrag->size;
 248
 249                         jffs2_fragtree_insert(this, newfrag);
 250                         rb_insert_color(&this->rb, list);
 251                         return 0;
 252                 }
 253         }
 254         /* OK, now we have newfrag added in the correct place in the tree, but
 255            frag_next(newfrag) may be a fragment which is overlapped by it
 256         */
 257         while ((this = frag_next(newfrag)) && newfrag->ofs + newfrag->size >= this->ofs + this->size) {
 258                 /* 'this' frag is obsoleted completely. */
 259                 D2(printk(KERN_DEBUG "Obsoleting node frag %p (%x-%x) and removing from tree\n", this, this->ofs, this->ofs+this->size));
 260                 rb_erase(&this->rb, list);
 261                 jffs2_obsolete_node_frag(c, this);
 262         }
 263         /* Now we're pointing at the first frag which isn't totally obsoleted by
 264            the new frag */
 265
 266         if (!this || newfrag->ofs + newfrag->size == this->ofs) {
 267                 return 0;
 268         }
 269         /* Still some overlap but we don't need to move it in the tree */
 270         this->size = (this->ofs + this->size) - (newfrag->ofs + newfrag->size);
 271         this->ofs = newfrag->ofs + newfrag->size;
 272
 273         /* And mark them REF_NORMAL so the GC takes a look at them */
 274         if (this->node)
 275                 mark_ref_normal(this->node->raw);
 276         mark_ref_normal(newfrag->node->raw);
 277
 278         return 0;
 279 }
 280
 281 /* Given an inode, probably with existing list of fragments, add the new node
 282  * to the fragment list.
 283  */
 284 int jffs2_add_full_dnode_to_inode(struct jffs2_sb_info *c, struct jffs2_inode_info *f, struct jffs2_full_dnode *fn)
 285 {
 286         int ret;
 287         struct jffs2_node_frag *newfrag;
 288
 289         D1(printk(KERN_DEBUG "jffs2_add_full_dnode_to_inode(ino #%u, f %p, fn %p)\n", f->inocache->ino, f, fn));
 290
 291         if (unlikely(!fn->size))
 292                 return 0;
 293
 294         newfrag = jffs2_alloc_node_frag();
 295         if (unlikely(!newfrag))
 296                 return -ENOMEM;
 297
 298         D2(printk(KERN_DEBUG "adding node %04x-%04x @0x%08x on flash, newfrag *%p\n",
 299                   fn->ofs, fn->ofs+fn->size, ref_offset(fn->raw), newfrag));
 300
 301         newfrag->ofs = fn->ofs;
 302         newfrag->size = fn->size;
 303         newfrag->node = fn;
 304         newfrag->node->frags = 1;
 305
 306         ret = jffs2_add_frag_to_fragtree(c, &f->fragtree, newfrag);
 307         if (unlikely(ret))
 308                 return ret;
 309
 310         /* If we now share a page with other nodes, mark either previous
 311            or next node REF_NORMAL, as appropriate.  */
 312         if (newfrag->ofs & (PAGE_CACHE_SIZE-1)) {
 313                 struct jffs2_node_frag *prev = frag_prev(newfrag);
 314
 315                 mark_ref_normal(fn->raw);
 316                 /* If we don't start at zero there's _always_ a previous */
 317                 if (prev->node)
 318                         mark_ref_normal(prev->node->raw);
 319         }
 320
 321         if ((newfrag->ofs+newfrag->size) & (PAGE_CACHE_SIZE-1)) {
 322                 struct jffs2_node_frag *next = frag_next(newfrag);
 323
 324                 if (next) {
 325                         mark_ref_normal(fn->raw);
 326                         if (next->node)
 327                                 mark_ref_normal(next->node->raw);
 328                 }
 329         }
 330         jffs2_dbg_fragtree_paranoia_check_nolock(f);
 331         jffs2_dbg_dump_fragtree_nolock(f);
 332         return 0;
 333 }
 334
 335
 336 void jffs2_set_inocache_state(struct jffs2_sb_info *c, struct jffs2_inode_cache *ic, int state)
 337 {
 338         spin_lock(&c->inocache_lock);
 339         ic->state = state;
 340         wake_up(&c->inocache_wq);
 341         spin_unlock(&c->inocache_lock);
 342 }
 343
 344 /* During mount, this needs no locking. During normal operation, its
 345    callers want to do other stuff while still holding the inocache_lock.
 346    Rather than introducing special case get_ino_cache functions or
 347    callbacks, we just let the caller do the locking itself. */
 348
 349 struct jffs2_inode_cache *jffs2_get_ino_cache(struct jffs2_sb_info *c, uint32_t ino)
 350 {
 351         struct jffs2_inode_cache *ret;
 352
 353         D2(printk(KERN_DEBUG "jffs2_get_ino_cache(): ino %u\n", ino));
 354
 355         ret = c->inocache_list[ino % INOCACHE_HASHSIZE];
 356         while (ret && ret->ino < ino) {
 357                 ret = ret->next;
 358         }
 359
 360         if (ret && ret->ino != ino)
 361                 ret = NULL;
 362
 363         D2(printk(KERN_DEBUG "jffs2_get_ino_cache found %p for ino %u\n", ret, ino));
 364         return ret;
 365 }
 366
 367 void jffs2_add_ino_cache (struct jffs2_sb_info *c, struct jffs2_inode_cache *new)
 368 {
 369         struct jffs2_inode_cache **prev;
 370
 371         spin_lock(&c->inocache_lock);
 372         if (!new->ino)
 373                 new->ino = ++c->highest_ino;
 374
 375         D2(printk(KERN_DEBUG "jffs2_add_ino_cache: Add %p (ino #%u)\n", new, new->ino));
 376
 377         prev = &c->inocache_list[new->ino % INOCACHE_HASHSIZE];
 378
 379         while ((*prev) && (*prev)->ino < new->ino) {
 380                 prev = &(*prev)->next;
 381         }
 382         new->next = *prev;
 383         *prev = new;
 384
 385         spin_unlock(&c->inocache_lock);
 386 }
 387
 388 void jffs2_del_ino_cache(struct jffs2_sb_info *c, struct jffs2_inode_cache *old)
 389 {
 390         struct jffs2_inode_cache **prev;
 391         D1(printk(KERN_DEBUG "jffs2_del_ino_cache: Del %p (ino #%u)\n", old, old->ino));
 392         spin_lock(&c->inocache_lock);
 393
 394         prev = &c->inocache_list[old->ino % INOCACHE_HASHSIZE];
 395
 396         while ((*prev) && (*prev)->ino < old->ino) {
 397                 prev = &(*prev)->next;
 398         }
 399         if ((*prev) == old) {
 400                 *prev = old->next;
 401         }
 402
 403         /* Free it now unless it's in READING or CLEARING state, which
 404            are the transitions upon read_inode() and clear_inode(). The
 405            rest of the time we know nobody else is looking at it, and
 406            if it's held by read_inode() or clear_inode() they'll free it
 407            for themselves. */
 408         if (old->state != INO_STATE_READING && old->state != INO_STATE_CLEARING)
 409                 jffs2_free_inode_cache(old);
 410
 411         spin_unlock(&c->inocache_lock);
 412 }
 413
 414 void jffs2_free_ino_caches(struct jffs2_sb_info *c)
 415 {
 416         int i;
 417         struct jffs2_inode_cache *this, *next;
 418
 419         for (i=0; i<INOCACHE_HASHSIZE; i++) {
 420                 this = c->inocache_list[i];
 421                 while (this) {
 422                         next = this->next;
 423                         jffs2_free_inode_cache(this);
 424                         this = next;
 425                 }
 426                 c->inocache_list[i] = NULL;
 427         }
 428 }
 429
 430 void jffs2_free_raw_node_refs(struct jffs2_sb_info *c)
 431 {
 432         int i;
 433         struct jffs2_raw_node_ref *this, *next;
 434
 435         for (i=0; i<c->nr_blocks; i++) {
 436                 this = c->blocks[i].first_node;
 437                 while(this) {
 438                         next = this->next_phys;
 439                         jffs2_free_raw_node_ref(this);
 440                         this = next;
 441                 }
 442                 c->blocks[i].first_node = c->blocks[i].last_node = NULL;
 443         }
 444 }
 445
 446 struct jffs2_node_frag *jffs2_lookup_node_frag(struct rb_root *fragtree, uint32_t offset)
 447 {
 448         /* The common case in lookup is that there will be a node
 449            which precisely matches. So we go looking for that first */
 450         struct rb_node *next;
 451         struct jffs2_node_frag *prev = NULL;
 452         struct jffs2_node_frag *frag = NULL;
 453
 454         D2(printk(KERN_DEBUG "jffs2_lookup_node_frag(%p, %d)\n", fragtree, offset));
 455
 456         next = fragtree->rb_node;
 457
 458         while(next) {
 459                 frag = rb_entry(next, struct jffs2_node_frag, rb);
 460
 461                 D2(printk(KERN_DEBUG "Considering frag %d-%d (%p). left %p, right %p\n",
 462                           frag->ofs, frag->ofs+frag->size, frag, frag->rb.rb_left, frag->rb.rb_right));
 463                 if (frag->ofs + frag->size <= offset) {
 464                         D2(printk(KERN_DEBUG "Going right from frag %d-%d, before the region we care about\n",
 465                                   frag->ofs, frag->ofs+frag->size));
 466                         /* Remember the closest smaller match on the way down */
 467                         if (!prev || frag->ofs > prev->ofs)
 468                                 prev = frag;
 469                         next = frag->rb.rb_right;
 470                 } else if (frag->ofs > offset) {
 471                         D2(printk(KERN_DEBUG "Going left from frag %d-%d, after the region we care about\n",
 472                                   frag->ofs, frag->ofs+frag->size));
 473                         next = frag->rb.rb_left;
 474                 } else {
 475                         D2(printk(KERN_DEBUG "Returning frag %d,%d, matched\n",
 476                                   frag->ofs, frag->ofs+frag->size));
 477                         return frag;
 478                 }
 479         }
 480
 481         /* Exact match not found. Go back up looking at each parent,
 482            and return the closest smaller one */
 483
 484         if (prev)
 485                 D2(printk(KERN_DEBUG "No match. Returning frag %d,%d, closest previous\n",
 486                           prev->ofs, prev->ofs+prev->size));
 487         else
 488                 D2(printk(KERN_DEBUG "Returning NULL, empty fragtree\n"));
 489
 490         return prev;
 491 }
 492
 493 /* Pass 'c' argument to indicate that nodes should be marked obsolete as
 494    they're killed. */
 495 void jffs2_kill_fragtree(struct rb_root *root, struct jffs2_sb_info *c)
 496 {
 497         struct jffs2_node_frag *frag;
 498         struct jffs2_node_frag *parent;
 499
 500         if (!root->rb_node)
 501                 return;
 502
 503         frag = (rb_entry(root->rb_node, struct jffs2_node_frag, rb));
 504
 505         while(frag) {
 506                 if (frag->rb.rb_left) {
 507                         D2(printk(KERN_DEBUG "Going left from frag (%p) %d-%d\n",
 508                                   frag, frag->ofs, frag->ofs+frag->size));
 509                         frag = frag_left(frag);
 510                         continue;
 511                 }
 512                 if (frag->rb.rb_right) {
 513                         D2(printk(KERN_DEBUG "Going right from frag (%p) %d-%d\n",
 514                                   frag, frag->ofs, frag->ofs+frag->size));
 515                         frag = frag_right(frag);
 516                         continue;
 517                 }
 518
 519                 D2(printk(KERN_DEBUG "jffs2_kill_fragtree: frag at 0x%x-0x%x: node %p, frags %d--\n",
 520                           frag->ofs, frag->ofs+frag->size, frag->node,
 521                           frag->node?frag->node->frags:0));
 522
 523                 if (frag->node && !(--frag->node->frags)) {
 524                         /* Not a hole, and it's the final remaining frag
 525                            of this node. Free the node */
 526                         if (c)
 527                                 jffs2_mark_node_obsolete(c, frag->node->raw);
 528
 529                         jffs2_free_full_dnode(frag->node);
 530                 }
 531                 parent = frag_parent(frag);
 532                 if (parent) {
 533                         if (frag_left(parent) == frag)
 534                                 parent->rb.rb_left = NULL;
 535                         else
 536                                 parent->rb.rb_right = NULL;
 537                 }
 538
 539                 jffs2_free_node_frag(frag);
 540                 frag = parent;
 541
 542                 cond_resched();
 543         }
 544 }