fs/jffs2/nodemgmt.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: nodemgmt.c,v 1.127 2005/09/20 15:49:12 dedekind Exp $
  11  *
  12  */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/slab.h>
  16 #include <linux/mtd/mtd.h>
  17 #include <linux/compiler.h>
  18 #include <linux/sched.h> /* For cond_resched() */
  19 #include "nodelist.h"
  20 #include "debug.h"
  21
  22 /**
  23  *      jffs2_reserve_space - request physical space to write nodes to flash
  24  *      @c: superblock info
  25  *      @minsize: Minimum acceptable size of allocation
  26  *      @ofs: Returned value of node offset
  27  *      @len: Returned value of allocation length
  28  *      @prio: Allocation type - ALLOC_{NORMAL,DELETION}
  29  *
  30  *      Requests a block of physical space on the flash. Returns zero for success
  31  *      and puts 'ofs' and 'len' into the appriopriate place, or returns -ENOSPC
  32  *      or other error if appropriate.
  33  *
  34  *      If it returns zero, jffs2_reserve_space() also downs the per-filesystem
  35  *      allocation semaphore, to prevent more than one allocation from being
  36  *      active at any time. The semaphore is later released by jffs2_commit_allocation()
  37  *
  38  *      jffs2_reserve_space() may trigger garbage collection in order to make room
  39  *      for the requested allocation.
  40  */
  41
  42 static int jffs2_do_reserve_space(struct jffs2_sb_info *c,  uint32_t minsize,
  43                                         uint32_t *ofs, uint32_t *len, uint32_t sumsize);
  44
  45 int jffs2_reserve_space(struct jffs2_sb_info *c, uint32_t minsize, uint32_t *ofs,
  46                         uint32_t *len, int prio, uint32_t sumsize)
  47 {
  48         int ret = -EAGAIN;
  49         int blocksneeded = c->resv_blocks_write;
  50         /* align it */
  51         minsize = PAD(minsize);
  52
  53         D1(printk(KERN_DEBUG "jffs2_reserve_space(): Requested 0x%x bytes\n", minsize));
  54         down(&c->alloc_sem);
  55
  56         D1(printk(KERN_DEBUG "jffs2_reserve_space(): alloc sem got\n"));
  57
  58         spin_lock(&c->erase_completion_lock);
  59
  60         /* this needs a little more thought (true <tglx> :)) */
  61         while(ret == -EAGAIN) {
  62                 while(c->nr_free_blocks + c->nr_erasing_blocks < blocksneeded) {
  63                         int ret;
  64                         uint32_t dirty, avail;
  65
  66                         /* calculate real dirty size
  67                          * dirty_size contains blocks on erase_pending_list
  68                          * those blocks are counted in c->nr_erasing_blocks.
  69                          * If one block is actually erased, it is not longer counted as dirty_space
  70                          * but it is counted in c->nr_erasing_blocks, so we add it and subtract it
  71                          * with c->nr_erasing_blocks * c->sector_size again.
  72                          * Blocks on erasable_list are counted as dirty_size, but not in c->nr_erasing_blocks
  73                          * This helps us to force gc and pick eventually a clean block to spread the load.
  74                          * We add unchecked_size here, as we hopefully will find some space to use.
  75                          * This will affect the sum only once, as gc first finishes checking
  76                          * of nodes.
  77                          */
  78                         dirty = c->dirty_size + c->erasing_size - c->nr_erasing_blocks * c->sector_size + c->unchecked_size;
  79                         if (dirty < c->nospc_dirty_size) {
  80                                 if (prio == ALLOC_DELETION && c->nr_free_blocks + c->nr_erasing_blocks >= c->resv_blocks_deletion) {
  81                                         D1(printk(KERN_NOTICE "jffs2_reserve_space(): Low on dirty space to GC, but it's a deletion. Allowing...\n"));
  82                                         break;
  83                                 }
  84                                 D1(printk(KERN_DEBUG "dirty size 0x%08x + unchecked_size 0x%08x < nospc_dirty_size 0x%08x, returning -ENOSPC\n",
  85                                           dirty, c->unchecked_size, c->sector_size));
  86
  87                                 spin_unlock(&c->erase_completion_lock);
  88                                 up(&c->alloc_sem);
  89                                 return -ENOSPC;
  90                         }
  91
  92                         /* Calc possibly available space. Possibly available means that we
  93                          * don't know, if unchecked size contains obsoleted nodes, which could give us some
  94                          * more usable space. This will affect the sum only once, as gc first finishes checking
  95                          * of nodes.
  96                          + Return -ENOSPC, if the maximum possibly available space is less or equal than
  97                          * blocksneeded * sector_size.
  98                          * This blocks endless gc looping on a filesystem, which is nearly full, even if
  99                          * the check above passes.
 100                          */
 101                         avail = c->free_size + c->dirty_size + c->erasing_size + c->unchecked_size;
 102                         if ( (avail / c->sector_size) <= blocksneeded) {
 103                                 if (prio == ALLOC_DELETION && c->nr_free_blocks + c->nr_erasing_blocks >= c->resv_blocks_deletion) {
 104                                         D1(printk(KERN_NOTICE "jffs2_reserve_space(): Low on possibly available space, but it's a deletion. Allowing...\n"));
 105                                         break;
 106                                 }
 107
 108                                 D1(printk(KERN_DEBUG "max. available size 0x%08x  < blocksneeded * sector_size 0x%08x, returning -ENOSPC\n",
 109                                           avail, blocksneeded * c->sector_size));
 110                                 spin_unlock(&c->erase_completion_lock);
 111                                 up(&c->alloc_sem);
 112                                 return -ENOSPC;
 113                         }
 114
 115                         up(&c->alloc_sem);
 116
 117                         D1(printk(KERN_DEBUG "Triggering GC pass. nr_free_blocks %d, nr_erasing_blocks %d, free_size 0x%08x, dirty_size 0x%08x, wasted_size 0x%08x, used_size 0x%08x, erasing_size 0x%08x, bad_size 0x%08x (total 0x%08x of 0x%08x)\n",
 118                                   c->nr_free_blocks, c->nr_erasing_blocks, c->free_size, c->dirty_size, c->wasted_size, c->used_size, c->erasing_size, c->bad_size,
 119                                   c->free_size + c->dirty_size + c->wasted_size + c->used_size + c->erasing_size + c->bad_size, c->flash_size));
 120                         spin_unlock(&c->erase_completion_lock);
 121
 122                         ret = jffs2_garbage_collect_pass(c);
 123                         if (ret)
 124                                 return ret;
 125
 126                         cond_resched();
 127
 128                         if (signal_pending(current))
 129                                 return -EINTR;
 130
 131                         down(&c->alloc_sem);
 132                         spin_lock(&c->erase_completion_lock);
 133                 }
 134
 135                 ret = jffs2_do_reserve_space(c, minsize, ofs, len, sumsize);
 136                 if (ret) {
 137                         D1(printk(KERN_DEBUG "jffs2_reserve_space: ret is %d\n", ret));
 138                 }
 139         }
 140         spin_unlock(&c->erase_completion_lock);
 141         if (ret)
 142                 up(&c->alloc_sem);
 143         return ret;
 144 }
 145
 146 int jffs2_reserve_space_gc(struct jffs2_sb_info *c, uint32_t minsize, uint32_t *ofs,
 147                         uint32_t *len, uint32_t sumsize)
 148 {
 149         int ret = -EAGAIN;
 150         minsize = PAD(minsize);
 151
 152         D1(printk(KERN_DEBUG "jffs2_reserve_space_gc(): Requested 0x%x bytes\n", minsize));
 153
 154         spin_lock(&c->erase_completion_lock);
 155         while(ret == -EAGAIN) {
 156                 ret = jffs2_do_reserve_space(c, minsize, ofs, len, sumsize);
 157                 if (ret) {
 158                         D1(printk(KERN_DEBUG "jffs2_reserve_space_gc: looping, ret is %d\n", ret));
 159                 }
 160         }
 161         spin_unlock(&c->erase_completion_lock);
 162         return ret;
 163 }
 164
 165
 166 /* Classify nextblock (clean, dirty of verydirty) and force to select an other one */
 167
 168 static void jffs2_close_nextblock(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
 169 {
 170
 171         /* Check, if we have a dirty block now, or if it was dirty already */
 172         if (ISDIRTY (jeb->wasted_size + jeb->dirty_size)) {
 173                 c->dirty_size += jeb->wasted_size;
 174                 c->wasted_size -= jeb->wasted_size;
 175                 jeb->dirty_size += jeb->wasted_size;
 176                 jeb->wasted_size = 0;
 177                 if (VERYDIRTY(c, jeb->dirty_size)) {
 178                         D1(printk(KERN_DEBUG "Adding full erase block at 0x%08x to very_dirty_list (free 0x%08x, dirty 0x%08x, used 0x%08x\n",
 179                           jeb->offset, jeb->free_size, jeb->dirty_size, jeb->used_size));
 180                         list_add_tail(&jeb->list, &c->very_dirty_list);
 181                 } else {
 182                         D1(printk(KERN_DEBUG "Adding full erase block at 0x%08x to dirty_list (free 0x%08x, dirty 0x%08x, used 0x%08x\n",
 183                           jeb->offset, jeb->free_size, jeb->dirty_size, jeb->used_size));
 184                         list_add_tail(&jeb->list, &c->dirty_list);
 185                 }
 186         } else {
 187                 D1(printk(KERN_DEBUG "Adding full erase block at 0x%08x to clean_list (free 0x%08x, dirty 0x%08x, used 0x%08x\n",
 188                   jeb->offset, jeb->free_size, jeb->dirty_size, jeb->used_size));
 189                 list_add_tail(&jeb->list, &c->clean_list);
 190         }
 191         c->nextblock = NULL;
 192
 193 }
 194
 195 /* Select a new jeb for nextblock */
 196
 197 static int jffs2_find_nextblock(struct jffs2_sb_info *c)
 198 {
 199         struct list_head *next;
 200
 201         /* Take the next block off the 'free' list */
 202
 203         if (list_empty(&c->free_list)) {
 204
 205                 if (!c->nr_erasing_blocks &&
 206                         !list_empty(&c->erasable_list)) {
 207                         struct jffs2_eraseblock *ejeb;
 208
 209                         ejeb = list_entry(c->erasable_list.next, struct jffs2_eraseblock, list);
 210                         list_del(&ejeb->list);
 211                         list_add_tail(&ejeb->list, &c->erase_pending_list);
 212                         c->nr_erasing_blocks++;
 213                         jffs2_erase_pending_trigger(c);
 214                         D1(printk(KERN_DEBUG "jffs2_find_nextblock: Triggering erase of erasable block at 0x%08x\n",
 215                                   ejeb->offset));
 216                 }
 217
 218                 if (!c->nr_erasing_blocks &&
 219                         !list_empty(&c->erasable_pending_wbuf_list)) {
 220                         D1(printk(KERN_DEBUG "jffs2_find_nextblock: Flushing write buffer\n"));
 221                         /* c->nextblock is NULL, no update to c->nextblock allowed */
 222                         spin_unlock(&c->erase_completion_lock);
 223                         jffs2_flush_wbuf_pad(c);
 224                         spin_lock(&c->erase_completion_lock);
 225                         /* Have another go. It'll be on the erasable_list now */
 226                         return -EAGAIN;
 227                 }
 228
 229                 if (!c->nr_erasing_blocks) {
 230                         /* Ouch. We're in GC, or we wouldn't have got here.
 231                            And there's no space left. At all. */
 232                         printk(KERN_CRIT "Argh. No free space left for GC. nr_erasing_blocks is %d. nr_free_blocks is %d. (erasableempty: %s, erasingempty: %s, erasependingempty: %s)\n",
 233                                    c->nr_erasing_blocks, c->nr_free_blocks, list_empty(&c->erasable_list)?"yes":"no",
 234                                    list_empty(&c->erasing_list)?"yes":"no", list_empty(&c->erase_pending_list)?"yes":"no");
 235                         return -ENOSPC;
 236                 }
 237
 238                 spin_unlock(&c->erase_completion_lock);
 239                 /* Don't wait for it; just erase one right now */
 240                 jffs2_erase_pending_blocks(c, 1);
 241                 spin_lock(&c->erase_completion_lock);
 242
 243                 /* An erase may have failed, decreasing the
 244                    amount of free space available. So we must
 245                    restart from the beginning */
 246                 return -EAGAIN;
 247         }
 248
 249         next = c->free_list.next;
 250         list_del(next);
 251         c->nextblock = list_entry(next, struct jffs2_eraseblock, list);
 252         c->nr_free_blocks--;
 253
 254         jffs2_sum_reset_collected(c->summary); /* reset collected summary */
 255
 256         D1(printk(KERN_DEBUG "jffs2_find_nextblock(): new nextblock = 0x%08x\n", c->nextblock->offset));
 257
 258         return 0;
 259 }
 260
 261 /* Called with alloc sem _and_ erase_completion_lock */
 262 static int jffs2_do_reserve_space(struct jffs2_sb_info *c, uint32_t minsize, uint32_t *ofs, uint32_t *len, uint32_t sumsize)
 263 {
 264         struct jffs2_eraseblock *jeb = c->nextblock;
 265         uint32_t reserved_size;                         /* for summary information at the end of the jeb */
 266         int ret;
 267
 268  restart:
 269         reserved_size = 0;
 270
 271         if (jffs2_sum_active() && (sumsize != JFFS2_SUMMARY_NOSUM_SIZE)) {
 272                                                         /* NOSUM_SIZE means not to generate summary */
 273
 274                 if (jeb) {
 275                         reserved_size = PAD(sumsize + c->summary->sum_size + JFFS2_SUMMARY_FRAME_SIZE);
 276                         dbg_summary("minsize=%d , jeb->free=%d ,"
 277                                                 "summary->size=%d , sumsize=%d\n",
 278                                                 minsize, jeb->free_size,
 279                                                 c->summary->sum_size, sumsize);
 280                 }
 281
 282                 /* Is there enough space for writing out the current node, or we have to
 283                    write out summary information now, close this jeb and select new nextblock? */
 284                 if (jeb && (PAD(minsize) + PAD(c->summary->sum_size + sumsize +
 285                                         JFFS2_SUMMARY_FRAME_SIZE) > jeb->free_size)) {
 286
 287                         /* Has summary been disabled for this jeb? */
 288                         if (jffs2_sum_is_disabled(c->summary)) {
 289                                 sumsize = JFFS2_SUMMARY_NOSUM_SIZE;
 290                                 goto restart;
 291                         }
 292
 293                         /* Writing out the collected summary information */
 294                         dbg_summary("generating summary for 0x%08x.\n", jeb->offset);
 295                         ret = jffs2_sum_write_sumnode(c);
 296
 297                         if (ret)
 298                                 return ret;
 299
 300                         if (jffs2_sum_is_disabled(c->summary)) {
 301                                 /* jffs2_write_sumnode() couldn't write out the summary information
 302                                    diabling summary for this jeb and free the collected information
 303                                  */
 304                                 sumsize = JFFS2_SUMMARY_NOSUM_SIZE;
 305                                 goto restart;
 306                         }
 307
 308                         jffs2_close_nextblock(c, jeb);
 309                         jeb = NULL;
 310                         /* keep always valid value in reserved_size */
 311                         reserved_size = PAD(sumsize + c->summary->sum_size + JFFS2_SUMMARY_FRAME_SIZE);
 312                 }
 313         } else {
 314                 if (jeb && minsize > jeb->free_size) {
 315                         /* Skip the end of this block and file it as having some dirty space */
 316                         /* If there's a pending write to it, flush now */
 317
 318                         if (jffs2_wbuf_dirty(c)) {
 319                                 spin_unlock(&c->erase_completion_lock);
 320                                 D1(printk(KERN_DEBUG "jffs2_do_reserve_space: Flushing write buffer\n"));
 321                                 jffs2_flush_wbuf_pad(c);
 322                                 spin_lock(&c->erase_completion_lock);
 323                                 jeb = c->nextblock;
 324                                 goto restart;
 325                         }
 326
 327                         c->wasted_size += jeb->free_size;
 328                         c->free_size -= jeb->free_size;
 329                         jeb->wasted_size += jeb->free_size;
 330                         jeb->free_size = 0;
 331
 332                         jffs2_close_nextblock(c, jeb);
 333                         jeb = NULL;
 334                 }
 335         }
 336
 337         if (!jeb) {
 338
 339                 ret = jffs2_find_nextblock(c);
 340                 if (ret)
 341                         return ret;
 342
 343                 jeb = c->nextblock;
 344
 345                 if (jeb->free_size != c->sector_size - c->cleanmarker_size) {
 346                         printk(KERN_WARNING "Eep. Block 0x%08x taken from free_list had free_size of 0x%08x!!\n", jeb->offset, jeb->free_size);
 347                         goto restart;
 348                 }
 349         }
 350         /* OK, jeb (==c->nextblock) is now pointing at a block which definitely has
 351            enough space */
 352         *ofs = jeb->offset + (c->sector_size - jeb->free_size);
 353         *len = jeb->free_size - reserved_size;
 354
 355         if (c->cleanmarker_size && jeb->used_size == c->cleanmarker_size &&
 356             !jeb->first_node->next_in_ino) {
 357                 /* Only node in it beforehand was a CLEANMARKER node (we think).
 358                    So mark it obsolete now that there's going to be another node
 359                    in the block. This will reduce used_size to zero but We've
 360                    already set c->nextblock so that jffs2_mark_node_obsolete()
 361                    won't try to refile it to the dirty_list.
 362                 */
 363                 spin_unlock(&c->erase_completion_lock);
 364                 jffs2_mark_node_obsolete(c, jeb->first_node);
 365                 spin_lock(&c->erase_completion_lock);
 366         }
 367
 368         D1(printk(KERN_DEBUG "jffs2_do_reserve_space(): Giving 0x%x bytes at 0x%x\n", *len, *ofs));
 369         return 0;
 370 }
 371
 372 /**
 373  *      jffs2_add_physical_node_ref - add a physical node reference to the list
 374  *      @c: superblock info
 375  *      @new: new node reference to add
 376  *      @len: length of this physical node
 377  *
 378  *      Should only be used to report nodes for which space has been allocated
 379  *      by jffs2_reserve_space.
 380  *
 381  *      Must be called with the alloc_sem held.
 382  */
 383
 384 int jffs2_add_physical_node_ref(struct jffs2_sb_info *c, struct jffs2_raw_node_ref *new,
 385                                 uint32_t len, struct jffs2_inode_cache *ic)
 386 {
 387         struct jffs2_eraseblock *jeb;
 388
 389         jeb = &c->blocks[new->flash_offset / c->sector_size];
 390 #ifdef TEST_TOTLEN
 391         new->__totlen = len;
 392 #endif
 393
 394         D1(printk(KERN_DEBUG "jffs2_add_physical_node_ref(): Node at 0x%x(%d), size 0x%x\n", ref_offset(new), ref_flags(new), len));
 395 #if 1
 396         /* we could get some obsolete nodes after nextblock was refiled
 397            in wbuf.c */
 398         if ((c->nextblock || !ref_obsolete(new))
 399             &&(jeb != c->nextblock || ref_offset(new) != jeb->offset + (c->sector_size - jeb->free_size))) {
 400                 printk(KERN_WARNING "argh. node added in wrong place\n");
 401                 jffs2_free_raw_node_ref(new);
 402                 return -EINVAL;
 403         }
 404 #endif
 405         spin_lock(&c->erase_completion_lock);
 406
 407         jffs2_link_node_ref(c, jeb, new, len, ic);
 408
 409         if (!jeb->free_size && !jeb->dirty_size && !ISDIRTY(jeb->wasted_size)) {
 410                 /* If it lives on the dirty_list, jffs2_reserve_space will put it there */
 411                 D1(printk(KERN_DEBUG "Adding full erase block at 0x%08x to clean_list (free 0x%08x, dirty 0x%08x, used 0x%08x\n",
 412                           jeb->offset, jeb->free_size, jeb->dirty_size, jeb->used_size));
 413                 if (jffs2_wbuf_dirty(c)) {
 414                         /* Flush the last write in the block if it's outstanding */
 415                         spin_unlock(&c->erase_completion_lock);
 416                         jffs2_flush_wbuf_pad(c);
 417                         spin_lock(&c->erase_completion_lock);
 418                 }
 419
 420                 list_add_tail(&jeb->list, &c->clean_list);
 421                 c->nextblock = NULL;
 422         }
 423         jffs2_dbg_acct_sanity_check_nolock(c,jeb);
 424         jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
 425
 426         spin_unlock(&c->erase_completion_lock);
 427
 428         return 0;
 429 }
 430
 431
 432 void jffs2_complete_reservation(struct jffs2_sb_info *c)
 433 {
 434         D1(printk(KERN_DEBUG "jffs2_complete_reservation()\n"));
 435         jffs2_garbage_collect_trigger(c);
 436         up(&c->alloc_sem);
 437 }
 438
 439 static inline int on_list(struct list_head *obj, struct list_head *head)
 440 {
 441         struct list_head *this;
 442
 443         list_for_each(this, head) {
 444                 if (this == obj) {
 445                         D1(printk("%p is on list at %p\n", obj, head));
 446                         return 1;
 447
 448                 }
 449         }
 450         return 0;
 451 }
 452
 453 void jffs2_mark_node_obsolete(struct jffs2_sb_info *c, struct jffs2_raw_node_ref *ref)
 454 {
 455         struct jffs2_eraseblock *jeb;
 456         int blocknr;
 457         struct jffs2_unknown_node n;
 458         int ret, addedsize;
 459         size_t retlen;
 460         uint32_t freed_len;
 461
 462         if(!ref) {
 463                 printk(KERN_NOTICE "EEEEEK. jffs2_mark_node_obsolete called with NULL node\n");
 464                 return;
 465         }
 466         if (ref_obsolete(ref)) {
 467                 D1(printk(KERN_DEBUG "jffs2_mark_node_obsolete called with already obsolete node at 0x%08x\n", ref_offset(ref)));
 468                 return;
 469         }
 470         blocknr = ref->flash_offset / c->sector_size;
 471         if (blocknr >= c->nr_blocks) {
 472                 printk(KERN_NOTICE "raw node at 0x%08x is off the end of device!\n", ref->flash_offset);
 473                 BUG();
 474         }
 475         jeb = &c->blocks[blocknr];
 476
 477         if (jffs2_can_mark_obsolete(c) && !jffs2_is_readonly(c) &&
 478             !(c->flags & (JFFS2_SB_FLAG_SCANNING | JFFS2_SB_FLAG_BUILDING))) {
 479                 /* Hm. This may confuse static lock analysis. If any of the above
 480                    three conditions is false, we're going to return from this
 481                    function without actually obliterating any nodes or freeing
 482                    any jffs2_raw_node_refs. So we don't need to stop erases from
 483                    happening, or protect against people holding an obsolete
 484                    jffs2_raw_node_ref without the erase_completion_lock. */
 485                 down(&c->erase_free_sem);
 486         }
 487
 488         spin_lock(&c->erase_completion_lock);
 489
 490         freed_len = ref_totlen(c, jeb, ref);
 491
 492         if (ref_flags(ref) == REF_UNCHECKED) {
 493                 D1(if (unlikely(jeb->unchecked_size < freed_len)) {
 494                         printk(KERN_NOTICE "raw unchecked node of size 0x%08x freed from erase block %d at 0x%08x, but unchecked_size was already 0x%08x\n",
 495                                freed_len, blocknr, ref->flash_offset, jeb->used_size);
 496                         BUG();
 497                 })
 498                 D1(printk(KERN_DEBUG "Obsoleting previously unchecked node at 0x%08x of len %x: ", ref_offset(ref), freed_len));
 499                 jeb->unchecked_size -= freed_len;
 500                 c->unchecked_size -= freed_len;
 501         } else {
 502                 D1(if (unlikely(jeb->used_size < freed_len)) {
 503                         printk(KERN_NOTICE "raw node of size 0x%08x freed from erase block %d at 0x%08x, but used_size was already 0x%08x\n",
 504                                freed_len, blocknr, ref->flash_offset, jeb->used_size);
 505                         BUG();
 506                 })
 507                 D1(printk(KERN_DEBUG "Obsoleting node at 0x%08x of len %#x: ", ref_offset(ref), freed_len));
 508                 jeb->used_size -= freed_len;
 509                 c->used_size -= freed_len;
 510         }
 511
 512         // Take care, that wasted size is taken into concern
 513         if ((jeb->dirty_size || ISDIRTY(jeb->wasted_size + freed_len)) && jeb != c->nextblock) {
 514                 D1(printk(KERN_DEBUG "Dirtying\n"));
 515                 addedsize = freed_len;
 516                 jeb->dirty_size += freed_len;
 517                 c->dirty_size += freed_len;
 518
 519                 /* Convert wasted space to dirty, if not a bad block */
 520                 if (jeb->wasted_size) {
 521                         if (on_list(&jeb->list, &c->bad_used_list)) {
 522                                 D1(printk(KERN_DEBUG "Leaving block at %08x on the bad_used_list\n",
 523                                           jeb->offset));
 524                                 addedsize = 0; /* To fool the refiling code later */
 525                         } else {
 526                                 D1(printk(KERN_DEBUG "Converting %d bytes of wasted space to dirty in block at %08x\n",
 527                                           jeb->wasted_size, jeb->offset));
 528                                 addedsize += jeb->wasted_size;
 529                                 jeb->dirty_size += jeb->wasted_size;
 530                                 c->dirty_size += jeb->wasted_size;
 531                                 c->wasted_size -= jeb->wasted_size;
 532                                 jeb->wasted_size = 0;
 533                         }
 534                 }
 535         } else {
 536                 D1(printk(KERN_DEBUG "Wasting\n"));
 537                 addedsize = 0;
 538                 jeb->wasted_size += freed_len;
 539                 c->wasted_size += freed_len;
 540         }
 541         ref->flash_offset = ref_offset(ref) | REF_OBSOLETE;
 542
 543         jffs2_dbg_acct_sanity_check_nolock(c, jeb);
 544         jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
 545
 546         if (c->flags & JFFS2_SB_FLAG_SCANNING) {
 547                 /* Flash scanning is in progress. Don't muck about with the block
 548                    lists because they're not ready yet, and don't actually
 549                    obliterate nodes that look obsolete. If they weren't
 550                    marked obsolete on the flash at the time they _became_
 551                    obsolete, there was probably a reason for that. */
 552                 spin_unlock(&c->erase_completion_lock);
 553                 /* We didn't lock the erase_free_sem */
 554                 return;
 555         }
 556
 557         if (jeb == c->nextblock) {
 558                 D2(printk(KERN_DEBUG "Not moving nextblock 0x%08x to dirty/erase_pending list\n", jeb->offset));
 559         } else if (!jeb->used_size && !jeb->unchecked_size) {
 560                 if (jeb == c->gcblock) {
 561                         D1(printk(KERN_DEBUG "gcblock at 0x%08x completely dirtied. Clearing gcblock...\n", jeb->offset));
 562                         c->gcblock = NULL;
 563                 } else {
 564                         D1(printk(KERN_DEBUG "Eraseblock at 0x%08x completely dirtied. Removing from (dirty?) list...\n", jeb->offset));
 565                         list_del(&jeb->list);
 566                 }
 567                 if (jffs2_wbuf_dirty(c)) {
 568                         D1(printk(KERN_DEBUG "...and adding to erasable_pending_wbuf_list\n"));
 569                         list_add_tail(&jeb->list, &c->erasable_pending_wbuf_list);
 570                 } else {
 571                         if (jiffies & 127) {
 572                                 /* Most of the time, we just erase it immediately. Otherwise we
 573                                    spend ages scanning it on mount, etc. */
 574                                 D1(printk(KERN_DEBUG "...and adding to erase_pending_list\n"));
 575                                 list_add_tail(&jeb->list, &c->erase_pending_list);
 576                                 c->nr_erasing_blocks++;
 577                                 jffs2_erase_pending_trigger(c);
 578                         } else {
 579                                 /* Sometimes, however, we leave it elsewhere so it doesn't get
 580                                    immediately reused, and we spread the load a bit. */
 581                                 D1(printk(KERN_DEBUG "...and adding to erasable_list\n"));
 582                                 list_add_tail(&jeb->list, &c->erasable_list);
 583                         }
 584                 }
 585                 D1(printk(KERN_DEBUG "Done OK\n"));
 586         } else if (jeb == c->gcblock) {
 587                 D2(printk(KERN_DEBUG "Not moving gcblock 0x%08x to dirty_list\n", jeb->offset));
 588         } else if (ISDIRTY(jeb->dirty_size) && !ISDIRTY(jeb->dirty_size - addedsize)) {
 589                 D1(printk(KERN_DEBUG "Eraseblock at 0x%08x is freshly dirtied. Removing from clean list...\n", jeb->offset));
 590                 list_del(&jeb->list);
 591                 D1(printk(KERN_DEBUG "...and adding to dirty_list\n"));
 592                 list_add_tail(&jeb->list, &c->dirty_list);
 593         } else if (VERYDIRTY(c, jeb->dirty_size) &&
 594                    !VERYDIRTY(c, jeb->dirty_size - addedsize)) {
 595                 D1(printk(KERN_DEBUG "Eraseblock at 0x%08x is now very dirty. Removing from dirty list...\n", jeb->offset));
 596                 list_del(&jeb->list);
 597                 D1(printk(KERN_DEBUG "...and adding to very_dirty_list\n"));
 598                 list_add_tail(&jeb->list, &c->very_dirty_list);
 599         } else {
 600                 D1(printk(KERN_DEBUG "Eraseblock at 0x%08x not moved anywhere. (free 0x%08x, dirty 0x%08x, used 0x%08x)\n",
 601                           jeb->offset, jeb->free_size, jeb->dirty_size, jeb->used_size));
 602         }
 603
 604         spin_unlock(&c->erase_completion_lock);
 605
 606         if (!jffs2_can_mark_obsolete(c) || jffs2_is_readonly(c) ||
 607                 (c->flags & JFFS2_SB_FLAG_BUILDING)) {
 608                 /* We didn't lock the erase_free_sem */
 609                 return;
 610         }
 611
 612         /* The erase_free_sem is locked, and has been since before we marked the node obsolete
 613            and potentially put its eraseblock onto the erase_pending_list. Thus, we know that
 614            the block hasn't _already_ been erased, and that 'ref' itself hasn't been freed yet
 615            by jffs2_free_all_node_refs() in erase.c. Which is nice. */
 616
 617         D1(printk(KERN_DEBUG "obliterating obsoleted node at 0x%08x\n", ref_offset(ref)));
 618         ret = jffs2_flash_read(c, ref_offset(ref), sizeof(n), &retlen, (char *)&n);
 619         if (ret) {
 620                 printk(KERN_WARNING "Read error reading from obsoleted node at 0x%08x: %d\n", ref_offset(ref), ret);
 621                 goto out_erase_sem;
 622         }
 623         if (retlen != sizeof(n)) {
 624                 printk(KERN_WARNING "Short read from obsoleted node at 0x%08x: %zd\n", ref_offset(ref), retlen);
 625                 goto out_erase_sem;
 626         }
 627         if (PAD(je32_to_cpu(n.totlen)) != PAD(freed_len)) {
 628                 printk(KERN_WARNING "Node totlen on flash (0x%08x) != totlen from node ref (0x%08x)\n", je32_to_cpu(n.totlen), freed_len);
 629                 goto out_erase_sem;
 630         }
 631         if (!(je16_to_cpu(n.nodetype) & JFFS2_NODE_ACCURATE)) {
 632                 D1(printk(KERN_DEBUG "Node at 0x%08x was already marked obsolete (nodetype 0x%04x)\n", ref_offset(ref), je16_to_cpu(n.nodetype)));
 633                 goto out_erase_sem;
 634         }
 635         /* XXX FIXME: This is ugly now */
 636         n.nodetype = cpu_to_je16(je16_to_cpu(n.nodetype) & ~JFFS2_NODE_ACCURATE);
 637         ret = jffs2_flash_write(c, ref_offset(ref), sizeof(n), &retlen, (char *)&n);
 638         if (ret) {
 639                 printk(KERN_WARNING "Write error in obliterating obsoleted node at 0x%08x: %d\n", ref_offset(ref), ret);
 640                 goto out_erase_sem;
 641         }
 642         if (retlen != sizeof(n)) {
 643                 printk(KERN_WARNING "Short write in obliterating obsoleted node at 0x%08x: %zd\n", ref_offset(ref), retlen);
 644                 goto out_erase_sem;
 645         }
 646
 647         /* Nodes which have been marked obsolete no longer need to be
 648            associated with any inode. Remove them from the per-inode list.
 649
 650            Note we can't do this for NAND at the moment because we need
 651            obsolete dirent nodes to stay on the lists, because of the
 652            horridness in jffs2_garbage_collect_deletion_dirent(). Also
 653            because we delete the inocache, and on NAND we need that to
 654            stay around until all the nodes are actually erased, in order
 655            to stop us from giving the same inode number to another newly
 656            created inode. */
 657         if (ref->next_in_ino) {
 658                 struct jffs2_inode_cache *ic;
 659                 struct jffs2_raw_node_ref **p;
 660
 661                 spin_lock(&c->erase_completion_lock);
 662
 663                 ic = jffs2_raw_ref_to_ic(ref);
 664                 /* It seems we should never call jffs2_mark_node_obsolete() for
 665                    XATTR nodes.... yet. Make sure we notice if/when we change
 666                    that :) */
 667                 BUG_ON(ic->class != RAWNODE_CLASS_INODE_CACHE);
 668                 for (p = &ic->nodes; (*p) != ref; p = &((*p)->next_in_ino))
 669                         ;
 670
 671                 *p = ref->next_in_ino;
 672                 ref->next_in_ino = NULL;
 673
 674                 if (ic->nodes == (void *)ic && ic->nlink == 0)
 675                         jffs2_del_ino_cache(c, ic);
 676
 677                 spin_unlock(&c->erase_completion_lock);
 678         }
 679
 680
 681         /* Merge with the next node in the physical list, if there is one
 682            and if it's also obsolete and if it doesn't belong to any inode */
 683         if (ref->next_phys && ref_obsolete(ref->next_phys) &&
 684             !ref->next_phys->next_in_ino) {
 685                 struct jffs2_raw_node_ref *n = ref->next_phys;
 686
 687                 spin_lock(&c->erase_completion_lock);
 688
 689 #ifdef TEST_TOTLEN
 690                 ref->__totlen += n->__totlen;
 691 #endif
 692                 ref->next_phys = n->next_phys;
 693                 if (jeb->last_node == n) jeb->last_node = ref;
 694                 if (jeb->gc_node == n) {
 695                         /* gc will be happy continuing gc on this node */
 696                         jeb->gc_node=ref;
 697                 }
 698                 spin_unlock(&c->erase_completion_lock);
 699
 700                 jffs2_free_raw_node_ref(n);
 701         }
 702
 703         /* Also merge with the previous node in the list, if there is one
 704            and that one is obsolete */
 705         if (ref != jeb->first_node ) {
 706                 struct jffs2_raw_node_ref *p = jeb->first_node;
 707
 708                 spin_lock(&c->erase_completion_lock);
 709
 710                 while (p->next_phys != ref)
 711                         p = p->next_phys;
 712
 713                 if (ref_obsolete(p) && !ref->next_in_ino) {
 714 #ifdef TEST_TOTLEN
 715                         p->__totlen += ref->__totlen;
 716 #endif
 717                         if (jeb->last_node == ref) {
 718                                 jeb->last_node = p;
 719                         }
 720                         if (jeb->gc_node == ref) {
 721                                 /* gc will be happy continuing gc on this node */
 722                                 jeb->gc_node=p;
 723                         }
 724                         p->next_phys = ref->next_phys;
 725                         jffs2_free_raw_node_ref(ref);
 726                 }
 727                 spin_unlock(&c->erase_completion_lock);
 728         }
 729  out_erase_sem:
 730         up(&c->erase_free_sem);
 731 }
 732
 733 int jffs2_thread_should_wake(struct jffs2_sb_info *c)
 734 {
 735         int ret = 0;
 736         uint32_t dirty;
 737
 738         if (c->unchecked_size) {
 739                 D1(printk(KERN_DEBUG "jffs2_thread_should_wake(): unchecked_size %d, checked_ino #%d\n",
 740                           c->unchecked_size, c->checked_ino));
 741                 return 1;
 742         }
 743
 744         /* dirty_size contains blocks on erase_pending_list
 745          * those blocks are counted in c->nr_erasing_blocks.
 746          * If one block is actually erased, it is not longer counted as dirty_space
 747          * but it is counted in c->nr_erasing_blocks, so we add it and subtract it
 748          * with c->nr_erasing_blocks * c->sector_size again.
 749          * Blocks on erasable_list are counted as dirty_size, but not in c->nr_erasing_blocks
 750          * This helps us to force gc and pick eventually a clean block to spread the load.
 751          */
 752         dirty = c->dirty_size + c->erasing_size - c->nr_erasing_blocks * c->sector_size;
 753
 754         if (c->nr_free_blocks + c->nr_erasing_blocks < c->resv_blocks_gctrigger &&
 755                         (dirty > c->nospc_dirty_size))
 756                 ret = 1;
 757
 758         D1(printk(KERN_DEBUG "jffs2_thread_should_wake(): nr_free_blocks %d, nr_erasing_blocks %d, dirty_size 0x%x: %s\n",
 759                   c->nr_free_blocks, c->nr_erasing_blocks, c->dirty_size, ret?"yes":"no"));
 760
 761         return ret;
 762 }