fs/jffs2/gc.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: gc.c,v 1.144 2004/12/21 11:18:50 dwmw2 Exp $
  11  *
  12  */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/mtd/mtd.h>
  16 #include <linux/slab.h>
  17 #include <linux/pagemap.h>
  18 #include <linux/crc32.h>
  19 #include <linux/compiler.h>
  20 #include <linux/stat.h>
  21 #include "nodelist.h"
  22 #include "compr.h"
  23
  24 static int jffs2_garbage_collect_pristine(struct jffs2_sb_info *c,
  25                                           struct jffs2_inode_cache *ic,
  26                                           struct jffs2_raw_node_ref *raw);
  27 static int jffs2_garbage_collect_metadata(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  28                                         struct jffs2_inode_info *f, struct jffs2_full_dnode *fd);
  29 static int jffs2_garbage_collect_dirent(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  30                                         struct jffs2_inode_info *f, struct jffs2_full_dirent *fd);
  31 static int jffs2_garbage_collect_deletion_dirent(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  32                                         struct jffs2_inode_info *f, struct jffs2_full_dirent *fd);
  33 static int jffs2_garbage_collect_hole(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  34                                       struct jffs2_inode_info *f, struct jffs2_full_dnode *fn,
  35                                       uint32_t start, uint32_t end);
  36 static int jffs2_garbage_collect_dnode(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  37                                        struct jffs2_inode_info *f, struct jffs2_full_dnode *fn,
  38                                        uint32_t start, uint32_t end);
  39 static int jffs2_garbage_collect_live(struct jffs2_sb_info *c,  struct jffs2_eraseblock *jeb,
  40                                struct jffs2_raw_node_ref *raw, struct jffs2_inode_info *f);
  41
  42 /* Called with erase_completion_lock held */
  43 static struct jffs2_eraseblock *jffs2_find_gc_block(struct jffs2_sb_info *c)
  44 {
  45         struct jffs2_eraseblock *ret;
  46         struct list_head *nextlist = NULL;
  47         int n = jiffies % 128;
  48
  49         /* Pick an eraseblock to garbage collect next. This is where we'll
  50            put the clever wear-levelling algorithms. Eventually.  */
  51         /* We possibly want to favour the dirtier blocks more when the
  52            number of free blocks is low. */
  53         if (!list_empty(&c->bad_used_list) && c->nr_free_blocks > c->resv_blocks_gcbad) {
  54                 D1(printk(KERN_DEBUG "Picking block from bad_used_list to GC next\n"));
  55                 nextlist = &c->bad_used_list;
  56         } else if (n < 50 && !list_empty(&c->erasable_list)) {
  57                 /* Note that most of them will have gone directly to be erased.
  58                    So don't favour the erasable_list _too_ much. */
  59                 D1(printk(KERN_DEBUG "Picking block from erasable_list to GC next\n"));
  60                 nextlist = &c->erasable_list;
  61         } else if (n < 110 && !list_empty(&c->very_dirty_list)) {
  62                 /* Most of the time, pick one off the very_dirty list */
  63                 D1(printk(KERN_DEBUG "Picking block from very_dirty_list to GC next\n"));
  64                 nextlist = &c->very_dirty_list;
  65         } else if (n < 126 && !list_empty(&c->dirty_list)) {
  66                 D1(printk(KERN_DEBUG "Picking block from dirty_list to GC next\n"));
  67                 nextlist = &c->dirty_list;
  68         } else if (!list_empty(&c->clean_list)) {
  69                 D1(printk(KERN_DEBUG "Picking block from clean_list to GC next\n"));
  70                 nextlist = &c->clean_list;
  71         } else if (!list_empty(&c->dirty_list)) {
  72                 D1(printk(KERN_DEBUG "Picking block from dirty_list to GC next (clean_list was empty)\n"));
  73
  74                 nextlist = &c->dirty_list;
  75         } else if (!list_empty(&c->very_dirty_list)) {
  76                 D1(printk(KERN_DEBUG "Picking block from very_dirty_list to GC next (clean_list and dirty_list were empty)\n"));
  77                 nextlist = &c->very_dirty_list;
  78         } else if (!list_empty(&c->erasable_list)) {
  79                 D1(printk(KERN_DEBUG "Picking block from erasable_list to GC next (clean_list and {very_,}dirty_list were empty)\n"));
  80
  81                 nextlist = &c->erasable_list;
  82         } else {
  83                 /* Eep. All were empty */
  84                 D1(printk(KERN_NOTICE "jffs2: No clean, dirty _or_ erasable blocks to GC from! Where are they all?\n"));
  85                 return NULL;
  86         }
  87
  88         ret = list_entry(nextlist->next, struct jffs2_eraseblock, list);
  89         list_del(&ret->list);
  90         c->gcblock = ret;
  91         ret->gc_node = ret->first_node;
  92         if (!ret->gc_node) {
  93                 printk(KERN_WARNING "Eep. ret->gc_node for block at 0x%08x is NULL\n", ret->offset);
  94                 BUG();
  95         }
  96
  97         /* Have we accidentally picked a clean block with wasted space ? */
  98         if (ret->wasted_size) {
  99                 D1(printk(KERN_DEBUG "Converting wasted_size %08x to dirty_size\n", ret->wasted_size));
 100                 ret->dirty_size += ret->wasted_size;
 101                 c->wasted_size -= ret->wasted_size;
 102                 c->dirty_size += ret->wasted_size;
 103                 ret->wasted_size = 0;
 104         }
 105
 106         D2(jffs2_dump_block_lists(c));
 107         return ret;
 108 }
 109
 110 /* jffs2_garbage_collect_pass
 111  * Make a single attempt to progress GC. Move one node, and possibly
 112  * start erasing one eraseblock.
 113  */
 114 int jffs2_garbage_collect_pass(struct jffs2_sb_info *c)
 115 {
 116         struct jffs2_inode_info *f;
 117         struct jffs2_inode_cache *ic;
 118         struct jffs2_eraseblock *jeb;
 119         struct jffs2_raw_node_ref *raw;
 120         int ret = 0, inum, nlink;
 121
 122         if (down_interruptible(&c->alloc_sem))
 123                 return -EINTR;
 124
 125         for (;;) {
 126                 spin_lock(&c->erase_completion_lock);
 127                 if (!c->unchecked_size)
 128                         break;
 129
 130                 /* We can't start doing GC yet. We haven't finished checking
 131                    the node CRCs etc. Do it now. */
 132
 133                 /* checked_ino is protected by the alloc_sem */
 134                 if (c->checked_ino > c->highest_ino) {
 135                         printk(KERN_CRIT "Checked all inodes but still 0x%x bytes of unchecked space?\n",
 136                                c->unchecked_size);
 137                         D2(jffs2_dump_block_lists(c));
 138                         spin_unlock(&c->erase_completion_lock);
 139                         BUG();
 140                 }
 141
 142                 spin_unlock(&c->erase_completion_lock);
 143
 144                 spin_lock(&c->inocache_lock);
 145
 146                 ic = jffs2_get_ino_cache(c, c->checked_ino++);
 147
 148                 if (!ic) {
 149                         spin_unlock(&c->inocache_lock);
 150                         continue;
 151                 }
 152
 153                 if (!ic->nlink) {
 154                         D1(printk(KERN_DEBUG "Skipping check of ino #%d with nlink zero\n",
 155                                   ic->ino));
 156                         spin_unlock(&c->inocache_lock);
 157                         continue;
 158                 }
 159                 switch(ic->state) {
 160                 case INO_STATE_CHECKEDABSENT:
 161                 case INO_STATE_PRESENT:
 162                         D1(printk(KERN_DEBUG "Skipping ino #%u already checked\n", ic->ino));
 163                         spin_unlock(&c->inocache_lock);
 164                         continue;
 165
 166                 case INO_STATE_GC:
 167                 case INO_STATE_CHECKING:
 168                         printk(KERN_WARNING "Inode #%u is in state %d during CRC check phase!\n", ic->ino, ic->state);
 169                         spin_unlock(&c->inocache_lock);
 170                         BUG();
 171
 172                 case INO_STATE_READING:
 173                         /* We need to wait for it to finish, lest we move on
 174                            and trigger the BUG() above while we haven't yet
 175                            finished checking all its nodes */
 176                         D1(printk(KERN_DEBUG "Waiting for ino #%u to finish reading\n", ic->ino));
 177                         up(&c->alloc_sem);
 178                         sleep_on_spinunlock(&c->inocache_wq, &c->inocache_lock);
 179                         return 0;
 180
 181                 default:
 182                         BUG();
 183
 184                 case INO_STATE_UNCHECKED:
 185                         ;
 186                 }
 187                 ic->state = INO_STATE_CHECKING;
 188                 spin_unlock(&c->inocache_lock);
 189
 190                 D1(printk(KERN_DEBUG "jffs2_garbage_collect_pass() triggering inode scan of ino#%u\n", ic->ino));
 191
 192                 ret = jffs2_do_crccheck_inode(c, ic);
 193                 if (ret)
 194                         printk(KERN_WARNING "Returned error for crccheck of ino #%u. Expect badness...\n", ic->ino);
 195
 196                 jffs2_set_inocache_state(c, ic, INO_STATE_CHECKEDABSENT);
 197                 up(&c->alloc_sem);
 198                 return ret;
 199         }
 200
 201         /* First, work out which block we're garbage-collecting */
 202         jeb = c->gcblock;
 203
 204         if (!jeb)
 205                 jeb = jffs2_find_gc_block(c);
 206
 207         if (!jeb) {
 208                 D1 (printk(KERN_NOTICE "jffs2: Couldn't find erase block to garbage collect!\n"));
 209                 spin_unlock(&c->erase_completion_lock);
 210                 up(&c->alloc_sem);
 211                 return -EIO;
 212         }
 213
 214         D1(printk(KERN_DEBUG "GC from block %08x, used_size %08x, dirty_size %08x, free_size %08x\n", jeb->offset, jeb->used_size, jeb->dirty_size, jeb->free_size));
 215         D1(if (c->nextblock)
 216            printk(KERN_DEBUG "Nextblock at  %08x, used_size %08x, dirty_size %08x, wasted_size %08x, free_size %08x\n", c->nextblock->offset, c->nextblock->used_size, c->nextblock->dirty_size, c->nextblock->wasted_size, c->nextblock->free_size));
 217
 218         if (!jeb->used_size) {
 219                 up(&c->alloc_sem);
 220                 goto eraseit;
 221         }
 222
 223         raw = jeb->gc_node;
 224
 225         while(ref_obsolete(raw)) {
 226                 D1(printk(KERN_DEBUG "Node at 0x%08x is obsolete... skipping\n", ref_offset(raw)));
 227                 raw = raw->next_phys;
 228                 if (unlikely(!raw)) {
 229                         printk(KERN_WARNING "eep. End of raw list while still supposedly nodes to GC\n");
 230                         printk(KERN_WARNING "erase block at 0x%08x. free_size 0x%08x, dirty_size 0x%08x, used_size 0x%08x\n",
 231                                jeb->offset, jeb->free_size, jeb->dirty_size, jeb->used_size);
 232                         jeb->gc_node = raw;
 233                         spin_unlock(&c->erase_completion_lock);
 234                         up(&c->alloc_sem);
 235                         BUG();
 236                 }
 237         }
 238         jeb->gc_node = raw;
 239
 240         D1(printk(KERN_DEBUG "Going to garbage collect node at 0x%08x\n", ref_offset(raw)));
 241
 242         if (!raw->next_in_ino) {
 243                 /* Inode-less node. Clean marker, snapshot or something like that */
 244                 /* FIXME: If it's something that needs to be copied, including something
 245                    we don't grok that has JFFS2_NODETYPE_RWCOMPAT_COPY, we should do so */
 246                 spin_unlock(&c->erase_completion_lock);
 247                 jffs2_mark_node_obsolete(c, raw);
 248                 up(&c->alloc_sem);
 249                 goto eraseit_lock;
 250         }
 251
 252         ic = jffs2_raw_ref_to_ic(raw);
 253
 254         /* We need to hold the inocache. Either the erase_completion_lock or
 255            the inocache_lock are sufficient; we trade down since the inocache_lock
 256            causes less contention. */
 257         spin_lock(&c->inocache_lock);
 258
 259         spin_unlock(&c->erase_completion_lock);
 260
 261         D1(printk(KERN_DEBUG "jffs2_garbage_collect_pass collecting from block @0x%08x. Node @0x%08x(%d), ino #%u\n", jeb->offset, ref_offset(raw), ref_flags(raw), ic->ino));
 262
 263         /* Three possibilities:
 264            1. Inode is already in-core. We must iget it and do proper
 265               updating to its fragtree, etc.
 266            2. Inode is not in-core, node is REF_PRISTINE. We lock the
 267               inocache to prevent a read_inode(), copy the node intact.
 268            3. Inode is not in-core, node is not pristine. We must iget()
 269               and take the slow path.
 270         */
 271
 272         switch(ic->state) {
 273         case INO_STATE_CHECKEDABSENT:
 274                 /* It's been checked, but it's not currently in-core.
 275                    We can just copy any pristine nodes, but have
 276                    to prevent anyone else from doing read_inode() while
 277                    we're at it, so we set the state accordingly */
 278                 if (ref_flags(raw) == REF_PRISTINE)
 279                         ic->state = INO_STATE_GC;
 280                 else {
 281                         D1(printk(KERN_DEBUG "Ino #%u is absent but node not REF_PRISTINE. Reading.\n",
 282                                   ic->ino));
 283                 }
 284                 break;
 285
 286         case INO_STATE_PRESENT:
 287                 /* It's in-core. GC must iget() it. */
 288                 break;
 289
 290         case INO_STATE_UNCHECKED:
 291         case INO_STATE_CHECKING:
 292         case INO_STATE_GC:
 293                 /* Should never happen. We should have finished checking
 294                    by the time we actually start doing any GC, and since
 295                    we're holding the alloc_sem, no other garbage collection
 296                    can happen.
 297                 */
 298                 printk(KERN_CRIT "Inode #%u already in state %d in jffs2_garbage_collect_pass()!\n",
 299                        ic->ino, ic->state);
 300                 up(&c->alloc_sem);
 301                 spin_unlock(&c->inocache_lock);
 302                 BUG();
 303
 304         case INO_STATE_READING:
 305                 /* Someone's currently trying to read it. We must wait for
 306                    them to finish and then go through the full iget() route
 307                    to do the GC. However, sometimes read_inode() needs to get
 308                    the alloc_sem() (for marking nodes invalid) so we must
 309                    drop the alloc_sem before sleeping. */
 310
 311                 up(&c->alloc_sem);
 312                 D1(printk(KERN_DEBUG "jffs2_garbage_collect_pass() waiting for ino #%u in state %d\n",
 313                           ic->ino, ic->state));
 314                 sleep_on_spinunlock(&c->inocache_wq, &c->inocache_lock);
 315                 /* And because we dropped the alloc_sem we must start again from the
 316                    beginning. Ponder chance of livelock here -- we're returning success
 317                    without actually making any progress.
 318
 319                    Q: What are the chances that the inode is back in INO_STATE_READING
 320                    again by the time we next enter this function? And that this happens
 321                    enough times to cause a real delay?
 322
 323                    A: Small enough that I don't care :)
 324                 */
 325                 return 0;
 326         }
 327
 328         /* OK. Now if the inode is in state INO_STATE_GC, we are going to copy the
 329            node intact, and we don't have to muck about with the fragtree etc.
 330            because we know it's not in-core. If it _was_ in-core, we go through
 331            all the iget() crap anyway */
 332
 333         if (ic->state == INO_STATE_GC) {
 334                 spin_unlock(&c->inocache_lock);
 335
 336                 ret = jffs2_garbage_collect_pristine(c, ic, raw);
 337
 338                 spin_lock(&c->inocache_lock);
 339                 ic->state = INO_STATE_CHECKEDABSENT;
 340                 wake_up(&c->inocache_wq);
 341
 342                 if (ret != -EBADFD) {
 343                         spin_unlock(&c->inocache_lock);
 344                         goto release_sem;
 345                 }
 346
 347                 /* Fall through if it wanted us to, with inocache_lock held */
 348         }
 349
 350         /* Prevent the fairly unlikely race where the gcblock is
 351            entirely obsoleted by the final close of a file which had
 352            the only valid nodes in the block, followed by erasure,
 353            followed by freeing of the ic because the erased block(s)
 354            held _all_ the nodes of that inode.... never been seen but
 355            it's vaguely possible. */
 356
 357         inum = ic->ino;
 358         nlink = ic->nlink;
 359         spin_unlock(&c->inocache_lock);
 360
 361         f = jffs2_gc_fetch_inode(c, inum, nlink);
 362         if (IS_ERR(f)) {
 363                 ret = PTR_ERR(f);
 364                 goto release_sem;
 365         }
 366         if (!f) {
 367                 ret = 0;
 368                 goto release_sem;
 369         }
 370
 371         ret = jffs2_garbage_collect_live(c, jeb, raw, f);
 372
 373         jffs2_gc_release_inode(c, f);
 374
 375  release_sem:
 376         up(&c->alloc_sem);
 377
 378  eraseit_lock:
 379         /* If we've finished this block, start it erasing */
 380         spin_lock(&c->erase_completion_lock);
 381
 382  eraseit:
 383         if (c->gcblock && !c->gcblock->used_size) {
 384                 D1(printk(KERN_DEBUG "Block at 0x%08x completely obsoleted by GC. Moving to erase_pending_list\n", c->gcblock->offset));
 385                 /* We're GC'ing an empty block? */
 386                 list_add_tail(&c->gcblock->list, &c->erase_pending_list);
 387                 c->gcblock = NULL;
 388                 c->nr_erasing_blocks++;
 389                 jffs2_erase_pending_trigger(c);
 390         }
 391         spin_unlock(&c->erase_completion_lock);
 392
 393         return ret;
 394 }
 395
 396 static int jffs2_garbage_collect_live(struct jffs2_sb_info *c,  struct jffs2_eraseblock *jeb,
 397                                       struct jffs2_raw_node_ref *raw, struct jffs2_inode_info *f)
 398 {
 399         struct jffs2_node_frag *frag;
 400         struct jffs2_full_dnode *fn = NULL;
 401         struct jffs2_full_dirent *fd;
 402         uint32_t start = 0, end = 0, nrfrags = 0;
 403         int ret = 0;
 404
 405         down(&f->sem);
 406
 407         /* Now we have the lock for this inode. Check that it's still the one at the head
 408            of the list. */
 409
 410         spin_lock(&c->erase_completion_lock);
 411
 412         if (c->gcblock != jeb) {
 413                 spin_unlock(&c->erase_completion_lock);
 414                 D1(printk(KERN_DEBUG "GC block is no longer gcblock. Restart\n"));
 415                 goto upnout;
 416         }
 417         if (ref_obsolete(raw)) {
 418                 spin_unlock(&c->erase_completion_lock);
 419                 D1(printk(KERN_DEBUG "node to be GC'd was obsoleted in the meantime.\n"));
 420                 /* They'll call again */
 421                 goto upnout;
 422         }
 423         spin_unlock(&c->erase_completion_lock);
 424
 425         /* OK. Looks safe. And nobody can get us now because we have the semaphore. Move the block */
 426         if (f->metadata && f->metadata->raw == raw) {
 427                 fn = f->metadata;
 428                 ret = jffs2_garbage_collect_metadata(c, jeb, f, fn);
 429                 goto upnout;
 430         }
 431
 432         /* FIXME. Read node and do lookup? */
 433         for (frag = frag_first(&f->fragtree); frag; frag = frag_next(frag)) {
 434                 if (frag->node && frag->node->raw == raw) {
 435                         fn = frag->node;
 436                         end = frag->ofs + frag->size;
 437                         if (!nrfrags++)
 438                                 start = frag->ofs;
 439                         if (nrfrags == frag->node->frags)
 440                                 break; /* We've found them all */
 441                 }
 442         }
 443         if (fn) {
 444                 if (ref_flags(raw) == REF_PRISTINE) {
 445                         ret = jffs2_garbage_collect_pristine(c, f->inocache, raw);
 446                         if (!ret) {
 447                                 /* Urgh. Return it sensibly. */
 448                                 frag->node->raw = f->inocache->nodes;
 449                         }
 450                         if (ret != -EBADFD)
 451                                 goto upnout;
 452                 }
 453                 /* We found a datanode. Do the GC */
 454                 if((start >> PAGE_CACHE_SHIFT) < ((end-1) >> PAGE_CACHE_SHIFT)) {
 455                         /* It crosses a page boundary. Therefore, it must be a hole. */
 456                         ret = jffs2_garbage_collect_hole(c, jeb, f, fn, start, end);
 457                 } else {
 458                         /* It could still be a hole. But we GC the page this way anyway */
 459                         ret = jffs2_garbage_collect_dnode(c, jeb, f, fn, start, end);
 460                 }
 461                 goto upnout;
 462         }
 463
 464         /* Wasn't a dnode. Try dirent */
 465         for (fd = f->dents; fd; fd=fd->next) {
 466                 if (fd->raw == raw)
 467                         break;
 468         }
 469
 470         if (fd && fd->ino) {
 471                 ret = jffs2_garbage_collect_dirent(c, jeb, f, fd);
 472         } else if (fd) {
 473                 ret = jffs2_garbage_collect_deletion_dirent(c, jeb, f, fd);
 474         } else {
 475                 printk(KERN_WARNING "Raw node at 0x%08x wasn't in node lists for ino #%u\n",
 476                        ref_offset(raw), f->inocache->ino);
 477                 if (ref_obsolete(raw)) {
 478                         printk(KERN_WARNING "But it's obsolete so we don't mind too much\n");
 479                 } else {
 480                         ret = -EIO;
 481                 }
 482         }
 483  upnout:
 484         up(&f->sem);
 485
 486         return ret;
 487 }
 488
 489 static int jffs2_garbage_collect_pristine(struct jffs2_sb_info *c,
 490                                           struct jffs2_inode_cache *ic,
 491                                           struct jffs2_raw_node_ref *raw)
 492 {
 493         union jffs2_node_union *node;
 494         struct jffs2_raw_node_ref *nraw;
 495         size_t retlen;
 496         int ret;
 497         uint32_t phys_ofs, alloclen;
 498         uint32_t crc, rawlen;
 499         int retried = 0;
 500
 501         D1(printk(KERN_DEBUG "Going to GC REF_PRISTINE node at 0x%08x\n", ref_offset(raw)));
 502
 503         rawlen = ref_totlen(c, c->gcblock, raw);
 504
 505         /* Ask for a small amount of space (or the totlen if smaller) because we
 506            don't want to force wastage of the end of a block if splitting would
 507            work. */
 508         ret = jffs2_reserve_space_gc(c, min_t(uint32_t, sizeof(struct jffs2_raw_inode) + JFFS2_MIN_DATA_LEN,
 509                                               rawlen), &phys_ofs, &alloclen);
 510         if (ret)
 511                 return ret;
 512
 513         if (alloclen < rawlen) {
 514                 /* Doesn't fit untouched. We'll go the old route and split it */
 515                 return -EBADFD;
 516         }
 517
 518         node = kmalloc(rawlen, GFP_KERNEL);
 519         if (!node)
 520                return -ENOMEM;
 521
 522         ret = jffs2_flash_read(c, ref_offset(raw), rawlen, &retlen, (char *)node);
 523         if (!ret && retlen != rawlen)
 524                 ret = -EIO;
 525         if (ret)
 526                 goto out_node;
 527
 528         crc = crc32(0, node, sizeof(struct jffs2_unknown_node)-4);
 529         if (je32_to_cpu(node->u.hdr_crc) != crc) {
 530                 printk(KERN_WARNING "Header CRC failed on REF_PRISTINE node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 531                        ref_offset(raw), je32_to_cpu(node->u.hdr_crc), crc);
 532                 goto bail;
 533         }
 534
 535         switch(je16_to_cpu(node->u.nodetype)) {
 536         case JFFS2_NODETYPE_INODE:
 537                 crc = crc32(0, node, sizeof(node->i)-8);
 538                 if (je32_to_cpu(node->i.node_crc) != crc) {
 539                         printk(KERN_WARNING "Node CRC failed on REF_PRISTINE data node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 540                                ref_offset(raw), je32_to_cpu(node->i.node_crc), crc);
 541                         goto bail;
 542                 }
 543
 544                 if (je32_to_cpu(node->i.dsize)) {
 545                         crc = crc32(0, node->i.data, je32_to_cpu(node->i.csize));
 546                         if (je32_to_cpu(node->i.data_crc) != crc) {
 547                                 printk(KERN_WARNING "Data CRC failed on REF_PRISTINE data node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 548                                        ref_offset(raw), je32_to_cpu(node->i.data_crc), crc);
 549                                 goto bail;
 550                         }
 551                 }
 552                 break;
 553
 554         case JFFS2_NODETYPE_DIRENT:
 555                 crc = crc32(0, node, sizeof(node->d)-8);
 556                 if (je32_to_cpu(node->d.node_crc) != crc) {
 557                         printk(KERN_WARNING "Node CRC failed on REF_PRISTINE dirent node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 558                                ref_offset(raw), je32_to_cpu(node->d.node_crc), crc);
 559                         goto bail;
 560                 }
 561
 562                 if (node->d.nsize) {
 563                         crc = crc32(0, node->d.name, node->d.nsize);
 564                         if (je32_to_cpu(node->d.name_crc) != crc) {
 565                                 printk(KERN_WARNING "Name CRC failed on REF_PRISTINE dirent ode at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 566                                        ref_offset(raw), je32_to_cpu(node->d.name_crc), crc);
 567                                 goto bail;
 568                         }
 569                 }
 570                 break;
 571         default:
 572                 printk(KERN_WARNING "Unknown node type for REF_PRISTINE node at 0x%08x: 0x%04x\n",
 573                        ref_offset(raw), je16_to_cpu(node->u.nodetype));
 574                 goto bail;
 575         }
 576
 577         nraw = jffs2_alloc_raw_node_ref();
 578         if (!nraw) {
 579                 ret = -ENOMEM;
 580                 goto out_node;
 581         }
 582
 583         /* OK, all the CRCs are good; this node can just be copied as-is. */
 584  retry:
 585         nraw->flash_offset = phys_ofs;
 586         nraw->__totlen = rawlen;
 587         nraw->next_phys = NULL;
 588
 589         ret = jffs2_flash_write(c, phys_ofs, rawlen, &retlen, (char *)node);
 590
 591         if (ret || (retlen != rawlen)) {
 592                 printk(KERN_NOTICE "Write of %d bytes at 0x%08x failed. returned %d, retlen %zd\n",
 593                        rawlen, phys_ofs, ret, retlen);
 594                 if (retlen) {
 595                         /* Doesn't belong to any inode */
 596                         nraw->next_in_ino = NULL;
 597
 598                         nraw->flash_offset |= REF_OBSOLETE;
 599                         jffs2_add_physical_node_ref(c, nraw);
 600                         jffs2_mark_node_obsolete(c, nraw);
 601                 } else {
 602                         printk(KERN_NOTICE "Not marking the space at 0x%08x as dirty because the flash driver returned retlen zero\n", nraw->flash_offset);
 603                         jffs2_free_raw_node_ref(nraw);
 604                 }
 605                 if (!retried && (nraw = jffs2_alloc_raw_node_ref())) {
 606                         /* Try to reallocate space and retry */
 607                         uint32_t dummy;
 608                         struct jffs2_eraseblock *jeb = &c->blocks[phys_ofs / c->sector_size];
 609
 610                         retried = 1;
 611
 612                         D1(printk(KERN_DEBUG "Retrying failed write of REF_PRISTINE node.\n"));
 613
 614                         ACCT_SANITY_CHECK(c,jeb);
 615                         D1(ACCT_PARANOIA_CHECK(jeb));
 616
 617                         ret = jffs2_reserve_space_gc(c, rawlen, &phys_ofs, &dummy);
 618
 619                         if (!ret) {
 620                                 D1(printk(KERN_DEBUG "Allocated space at 0x%08x to retry failed write.\n", phys_ofs));
 621
 622                                 ACCT_SANITY_CHECK(c,jeb);
 623                                 D1(ACCT_PARANOIA_CHECK(jeb));
 624
 625                                 goto retry;
 626                         }
 627                         D1(printk(KERN_DEBUG "Failed to allocate space to retry failed write: %d!\n", ret));
 628                         jffs2_free_raw_node_ref(nraw);
 629                 }
 630
 631                 jffs2_free_raw_node_ref(nraw);
 632                 if (!ret)
 633                         ret = -EIO;
 634                 goto out_node;
 635         }
 636         nraw->flash_offset |= REF_PRISTINE;
 637         jffs2_add_physical_node_ref(c, nraw);
 638
 639         /* Link into per-inode list. This is safe because of the ic
 640            state being INO_STATE_GC. Note that if we're doing this
 641            for an inode which is in-core, the 'nraw' pointer is then
 642            going to be fetched from ic->nodes by our caller. */
 643         spin_lock(&c->erase_completion_lock);
 644         nraw->next_in_ino = ic->nodes;
 645         ic->nodes = nraw;
 646         spin_unlock(&c->erase_completion_lock);
 647
 648         jffs2_mark_node_obsolete(c, raw);
 649         D1(printk(KERN_DEBUG "WHEEE! GC REF_PRISTINE node at 0x%08x succeeded\n", ref_offset(raw)));
 650
 651  out_node:
 652         kfree(node);
 653         return ret;
 654  bail:
 655         ret = -EBADFD;
 656         goto out_node;
 657 }
 658
 659 static int jffs2_garbage_collect_metadata(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 660                                         struct jffs2_inode_info *f, struct jffs2_full_dnode *fn)
 661 {
 662         struct jffs2_full_dnode *new_fn;
 663         struct jffs2_raw_inode ri;
 664         jint16_t dev;
 665         char *mdata = NULL, mdatalen = 0;
 666         uint32_t alloclen, phys_ofs;
 667         int ret;
 668
 669         if (S_ISBLK(JFFS2_F_I_MODE(f)) ||
 670             S_ISCHR(JFFS2_F_I_MODE(f)) ) {
 671                 /* For these, we don't actually need to read the old node */
 672                 /* FIXME: for minor or major > 255. */
 673                 dev = cpu_to_je16(((JFFS2_F_I_RDEV_MAJ(f) << 8) |
 674                         JFFS2_F_I_RDEV_MIN(f)));
 675                 mdata = (char *)&dev;
 676                 mdatalen = sizeof(dev);
 677                 D1(printk(KERN_DEBUG "jffs2_garbage_collect_metadata(): Writing %d bytes of kdev_t\n", mdatalen));
 678         } else if (S_ISLNK(JFFS2_F_I_MODE(f))) {
 679                 mdatalen = fn->size;
 680                 mdata = kmalloc(fn->size, GFP_KERNEL);
 681                 if (!mdata) {
 682                         printk(KERN_WARNING "kmalloc of mdata failed in jffs2_garbage_collect_metadata()\n");
 683                         return -ENOMEM;
 684                 }
 685                 ret = jffs2_read_dnode(c, f, fn, mdata, 0, mdatalen);
 686                 if (ret) {
 687                         printk(KERN_WARNING "read of old metadata failed in jffs2_garbage_collect_metadata(): %d\n", ret);
 688                         kfree(mdata);
 689                         return ret;
 690                 }
 691                 D1(printk(KERN_DEBUG "jffs2_garbage_collect_metadata(): Writing %d bites of symlink target\n", mdatalen));
 692
 693         }
 694
 695         ret = jffs2_reserve_space_gc(c, sizeof(ri) + mdatalen, &phys_ofs, &alloclen);
 696         if (ret) {
 697                 printk(KERN_WARNING "jffs2_reserve_space_gc of %zd bytes for garbage_collect_metadata failed: %d\n",
 698                        sizeof(ri)+ mdatalen, ret);
 699                 goto out;
 700         }
 701
 702         memset(&ri, 0, sizeof(ri));
 703         ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
 704         ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
 705         ri.totlen = cpu_to_je32(sizeof(ri) + mdatalen);
 706         ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
 707
 708         ri.ino = cpu_to_je32(f->inocache->ino);
 709         ri.version = cpu_to_je32(++f->highest_version);
 710         ri.mode = cpu_to_jemode(JFFS2_F_I_MODE(f));
 711         ri.uid = cpu_to_je16(JFFS2_F_I_UID(f));
 712         ri.gid = cpu_to_je16(JFFS2_F_I_GID(f));
 713         ri.isize = cpu_to_je32(JFFS2_F_I_SIZE(f));
 714         ri.atime = cpu_to_je32(JFFS2_F_I_ATIME(f));
 715         ri.ctime = cpu_to_je32(JFFS2_F_I_CTIME(f));
 716         ri.mtime = cpu_to_je32(JFFS2_F_I_MTIME(f));
 717         ri.offset = cpu_to_je32(0);
 718         ri.csize = cpu_to_je32(mdatalen);
 719         ri.dsize = cpu_to_je32(mdatalen);
 720         ri.compr = JFFS2_COMPR_NONE;
 721         ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
 722         ri.data_crc = cpu_to_je32(crc32(0, mdata, mdatalen));
 723
 724         new_fn = jffs2_write_dnode(c, f, &ri, mdata, mdatalen, phys_ofs, ALLOC_GC);
 725
 726         if (IS_ERR(new_fn)) {
 727                 printk(KERN_WARNING "Error writing new dnode: %ld\n", PTR_ERR(new_fn));
 728                 ret = PTR_ERR(new_fn);
 729                 goto out;
 730         }
 731         jffs2_mark_node_obsolete(c, fn->raw);
 732         jffs2_free_full_dnode(fn);
 733         f->metadata = new_fn;
 734  out:
 735         if (S_ISLNK(JFFS2_F_I_MODE(f)))
 736                 kfree(mdata);
 737         return ret;
 738 }
 739
 740 static int jffs2_garbage_collect_dirent(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 741                                         struct jffs2_inode_info *f, struct jffs2_full_dirent *fd)
 742 {
 743         struct jffs2_full_dirent *new_fd;
 744         struct jffs2_raw_dirent rd;
 745         uint32_t alloclen, phys_ofs;
 746         int ret;
 747
 748         rd.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
 749         rd.nodetype = cpu_to_je16(JFFS2_NODETYPE_DIRENT);
 750         rd.nsize = strlen(fd->name);
 751         rd.totlen = cpu_to_je32(sizeof(rd) + rd.nsize);
 752         rd.hdr_crc = cpu_to_je32(crc32(0, &rd, sizeof(struct jffs2_unknown_node)-4));
 753
 754         rd.pino = cpu_to_je32(f->inocache->ino);
 755         rd.version = cpu_to_je32(++f->highest_version);
 756         rd.ino = cpu_to_je32(fd->ino);
 757         rd.mctime = cpu_to_je32(max(JFFS2_F_I_MTIME(f), JFFS2_F_I_CTIME(f)));
 758         rd.type = fd->type;
 759         rd.node_crc = cpu_to_je32(crc32(0, &rd, sizeof(rd)-8));
 760         rd.name_crc = cpu_to_je32(crc32(0, fd->name, rd.nsize));
 761
 762         ret = jffs2_reserve_space_gc(c, sizeof(rd)+rd.nsize, &phys_ofs, &alloclen);
 763         if (ret) {
 764                 printk(KERN_WARNING "jffs2_reserve_space_gc of %zd bytes for garbage_collect_dirent failed: %d\n",
 765                        sizeof(rd)+rd.nsize, ret);
 766                 return ret;
 767         }
 768         new_fd = jffs2_write_dirent(c, f, &rd, fd->name, rd.nsize, phys_ofs, ALLOC_GC);
 769
 770         if (IS_ERR(new_fd)) {
 771                 printk(KERN_WARNING "jffs2_write_dirent in garbage_collect_dirent failed: %ld\n", PTR_ERR(new_fd));
 772                 return PTR_ERR(new_fd);
 773         }
 774         jffs2_add_fd_to_list(c, new_fd, &f->dents);
 775         return 0;
 776 }
 777
 778 static int jffs2_garbage_collect_deletion_dirent(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 779                                         struct jffs2_inode_info *f, struct jffs2_full_dirent *fd)
 780 {
 781         struct jffs2_full_dirent **fdp = &f->dents;
 782         int found = 0;
 783
 784         /* On a medium where we can't actually mark nodes obsolete
 785            pernamently, such as NAND flash, we need to work out
 786            whether this deletion dirent is still needed to actively
 787            delete a 'real' dirent with the same name that's still
 788            somewhere else on the flash. */
 789         if (!jffs2_can_mark_obsolete(c)) {
 790                 struct jffs2_raw_dirent *rd;
 791                 struct jffs2_raw_node_ref *raw;
 792                 int ret;
 793                 size_t retlen;
 794                 int name_len = strlen(fd->name);
 795                 uint32_t name_crc = crc32(0, fd->name, name_len);
 796                 uint32_t rawlen = ref_totlen(c, jeb, fd->raw);
 797
 798                 rd = kmalloc(rawlen, GFP_KERNEL);
 799                 if (!rd)
 800                         return -ENOMEM;
 801
 802                 /* Prevent the erase code from nicking the obsolete node refs while
 803                    we're looking at them. I really don't like this extra lock but
 804                    can't see any alternative. Suggestions on a postcard to... */
 805                 down(&c->erase_free_sem);
 806
 807                 for (raw = f->inocache->nodes; raw != (void *)f->inocache; raw = raw->next_in_ino) {
 808
 809                         /* We only care about obsolete ones */
 810                         if (!(ref_obsolete(raw)))
 811                                 continue;
 812
 813                         /* Any dirent with the same name is going to have the same length... */
 814                         if (ref_totlen(c, NULL, raw) != rawlen)
 815                                 continue;
 816
 817                         /* Doesn't matter if there's one in the same erase block. We're going to
 818                            delete it too at the same time. */
 819                         if ((raw->flash_offset & ~(c->sector_size-1)) ==
 820                             (fd->raw->flash_offset & ~(c->sector_size-1)))
 821                                 continue;
 822
 823                         D1(printk(KERN_DEBUG "Check potential deletion dirent at %08x\n", ref_offset(raw)));
 824
 825                         /* This is an obsolete node belonging to the same directory, and it's of the right
 826                            length. We need to take a closer look...*/
 827                         ret = jffs2_flash_read(c, ref_offset(raw), rawlen, &retlen, (char *)rd);
 828                         if (ret) {
 829                                 printk(KERN_WARNING "jffs2_g_c_deletion_dirent(): Read error (%d) reading obsolete node at %08x\n", ret, ref_offset(raw));
 830                                 /* If we can't read it, we don't need to continue to obsolete it. Continue */
 831                                 continue;
 832                         }
 833                         if (retlen != rawlen) {
 834                                 printk(KERN_WARNING "jffs2_g_c_deletion_dirent(): Short read (%zd not %u) reading header from obsolete node at %08x\n",
 835                                        retlen, rawlen, ref_offset(raw));
 836                                 continue;
 837                         }
 838
 839                         if (je16_to_cpu(rd->nodetype) != JFFS2_NODETYPE_DIRENT)
 840                                 continue;
 841
 842                         /* If the name CRC doesn't match, skip */
 843                         if (je32_to_cpu(rd->name_crc) != name_crc)
 844                                 continue;
 845
 846                         /* If the name length doesn't match, or it's another deletion dirent, skip */
 847                         if (rd->nsize != name_len || !je32_to_cpu(rd->ino))
 848                                 continue;
 849
 850                         /* OK, check the actual name now */
 851                         if (memcmp(rd->name, fd->name, name_len))
 852                                 continue;
 853
 854                         /* OK. The name really does match. There really is still an older node on
 855                            the flash which our deletion dirent obsoletes. So we have to write out
 856                            a new deletion dirent to replace it */
 857                         up(&c->erase_free_sem);
 858
 859                         D1(printk(KERN_DEBUG "Deletion dirent at %08x still obsoletes real dirent \"%s\" at %08x for ino #%u\n",
 860                                   ref_offset(fd->raw), fd->name, ref_offset(raw), je32_to_cpu(rd->ino)));
 861                         kfree(rd);
 862
 863                         return jffs2_garbage_collect_dirent(c, jeb, f, fd);
 864                 }
 865
 866                 up(&c->erase_free_sem);
 867                 kfree(rd);
 868         }
 869
 870         /* No need for it any more. Just mark it obsolete and remove it from the list */
 871         while (*fdp) {
 872                 if ((*fdp) == fd) {
 873                         found = 1;
 874                         *fdp = fd->next;
 875                         break;
 876                 }
 877                 fdp = &(*fdp)->next;
 878         }
 879         if (!found) {
 880                 printk(KERN_WARNING "Deletion dirent \"%s\" not found in list for ino #%u\n", fd->name, f->inocache->ino);
 881         }
 882         jffs2_mark_node_obsolete(c, fd->raw);
 883         jffs2_free_full_dirent(fd);
 884         return 0;
 885 }
 886
 887 static int jffs2_garbage_collect_hole(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 888                                       struct jffs2_inode_info *f, struct jffs2_full_dnode *fn,
 889                                       uint32_t start, uint32_t end)
 890 {
 891         struct jffs2_raw_inode ri;
 892         struct jffs2_node_frag *frag;
 893         struct jffs2_full_dnode *new_fn;
 894         uint32_t alloclen, phys_ofs;
 895         int ret;
 896
 897         D1(printk(KERN_DEBUG "Writing replacement hole node for ino #%u from offset 0x%x to 0x%x\n",
 898                   f->inocache->ino, start, end));
 899
 900         memset(&ri, 0, sizeof(ri));
 901
 902         if(fn->frags > 1) {
 903                 size_t readlen;
 904                 uint32_t crc;
 905                 /* It's partially obsoleted by a later write. So we have to
 906                    write it out again with the _same_ version as before */
 907                 ret = jffs2_flash_read(c, ref_offset(fn->raw), sizeof(ri), &readlen, (char *)&ri);
 908                 if (readlen != sizeof(ri) || ret) {
 909                         printk(KERN_WARNING "Node read failed in jffs2_garbage_collect_hole. Ret %d, retlen %zd. Data will be lost by writing new hole node\n", ret, readlen);
 910                         goto fill;
 911                 }
 912                 if (je16_to_cpu(ri.nodetype) != JFFS2_NODETYPE_INODE) {
 913                         printk(KERN_WARNING "jffs2_garbage_collect_hole: Node at 0x%08x had node type 0x%04x instead of JFFS2_NODETYPE_INODE(0x%04x)\n",
 914                                ref_offset(fn->raw),
 915                                je16_to_cpu(ri.nodetype), JFFS2_NODETYPE_INODE);
 916                         return -EIO;
 917                 }
 918                 if (je32_to_cpu(ri.totlen) != sizeof(ri)) {
 919                         printk(KERN_WARNING "jffs2_garbage_collect_hole: Node at 0x%08x had totlen 0x%x instead of expected 0x%zx\n",
 920                                ref_offset(fn->raw),
 921                                je32_to_cpu(ri.totlen), sizeof(ri));
 922                         return -EIO;
 923                 }
 924                 crc = crc32(0, &ri, sizeof(ri)-8);
 925                 if (crc != je32_to_cpu(ri.node_crc)) {
 926                         printk(KERN_WARNING "jffs2_garbage_collect_hole: Node at 0x%08x had CRC 0x%08x which doesn't match calculated CRC 0x%08x\n",
 927                                ref_offset(fn->raw),
 928                                je32_to_cpu(ri.node_crc), crc);
 929                         /* FIXME: We could possibly deal with this by writing new holes for each frag */
 930                         printk(KERN_WARNING "Data in the range 0x%08x to 0x%08x of inode #%u will be lost\n",
 931                                start, end, f->inocache->ino);
 932                         goto fill;
 933                 }
 934                 if (ri.compr != JFFS2_COMPR_ZERO) {
 935                         printk(KERN_WARNING "jffs2_garbage_collect_hole: Node 0x%08x wasn't a hole node!\n", ref_offset(fn->raw));
 936                         printk(KERN_WARNING "Data in the range 0x%08x to 0x%08x of inode #%u will be lost\n",
 937                                start, end, f->inocache->ino);
 938                         goto fill;
 939                 }
 940         } else {
 941         fill:
 942                 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
 943                 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
 944                 ri.totlen = cpu_to_je32(sizeof(ri));
 945                 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
 946
 947                 ri.ino = cpu_to_je32(f->inocache->ino);
 948                 ri.version = cpu_to_je32(++f->highest_version);
 949                 ri.offset = cpu_to_je32(start);
 950                 ri.dsize = cpu_to_je32(end - start);
 951                 ri.csize = cpu_to_je32(0);
 952                 ri.compr = JFFS2_COMPR_ZERO;
 953         }
 954         ri.mode = cpu_to_jemode(JFFS2_F_I_MODE(f));
 955         ri.uid = cpu_to_je16(JFFS2_F_I_UID(f));
 956         ri.gid = cpu_to_je16(JFFS2_F_I_GID(f));
 957         ri.isize = cpu_to_je32(JFFS2_F_I_SIZE(f));
 958         ri.atime = cpu_to_je32(JFFS2_F_I_ATIME(f));
 959         ri.ctime = cpu_to_je32(JFFS2_F_I_CTIME(f));
 960         ri.mtime = cpu_to_je32(JFFS2_F_I_MTIME(f));
 961         ri.data_crc = cpu_to_je32(0);
 962         ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
 963
 964         ret = jffs2_reserve_space_gc(c, sizeof(ri), &phys_ofs, &alloclen);
 965         if (ret) {
 966                 printk(KERN_WARNING "jffs2_reserve_space_gc of %zd bytes for garbage_collect_hole failed: %d\n",
 967                        sizeof(ri), ret);
 968                 return ret;
 969         }
 970         new_fn = jffs2_write_dnode(c, f, &ri, NULL, 0, phys_ofs, ALLOC_GC);
 971
 972         if (IS_ERR(new_fn)) {
 973                 printk(KERN_WARNING "Error writing new hole node: %ld\n", PTR_ERR(new_fn));
 974                 return PTR_ERR(new_fn);
 975         }
 976         if (je32_to_cpu(ri.version) == f->highest_version) {
 977                 jffs2_add_full_dnode_to_inode(c, f, new_fn);
 978                 if (f->metadata) {
 979                         jffs2_mark_node_obsolete(c, f->metadata->raw);
 980                         jffs2_free_full_dnode(f->metadata);
 981                         f->metadata = NULL;
 982                 }
 983                 return 0;
 984         }
 985
 986         /*
 987          * We should only get here in the case where the node we are
 988          * replacing had more than one frag, so we kept the same version
 989          * number as before. (Except in case of error -- see 'goto fill;'
 990          * above.)
 991          */
 992         D1(if(unlikely(fn->frags <= 1)) {
 993                 printk(KERN_WARNING "jffs2_garbage_collect_hole: Replacing fn with %d frag(s) but new ver %d != highest_version %d of ino #%d\n",
 994                        fn->frags, je32_to_cpu(ri.version), f->highest_version,
 995                        je32_to_cpu(ri.ino));
 996         });
 997
 998         /* This is a partially-overlapped hole node. Mark it REF_NORMAL not REF_PRISTINE */
 999         mark_ref_normal(new_fn->raw);
1000
1001         for (frag = jffs2_lookup_node_frag(&f->fragtree, fn->ofs);
1002              frag; frag = frag_next(frag)) {
1003                 if (frag->ofs > fn->size + fn->ofs)
1004                         break;
1005                 if (frag->node == fn) {
1006                         frag->node = new_fn;
1007                         new_fn->frags++;
1008                         fn->frags--;
1009                 }
1010         }
1011         if (fn->frags) {
1012                 printk(KERN_WARNING "jffs2_garbage_collect_hole: Old node still has frags!\n");
1013                 BUG();
1014         }
1015         if (!new_fn->frags) {
1016                 printk(KERN_WARNING "jffs2_garbage_collect_hole: New node has no frags!\n");
1017                 BUG();
1018         }
1019
1020         jffs2_mark_node_obsolete(c, fn->raw);
1021         jffs2_free_full_dnode(fn);
1022
1023         return 0;
1024 }
1025
1026 static int jffs2_garbage_collect_dnode(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
1027                                        struct jffs2_inode_info *f, struct jffs2_full_dnode *fn,
1028                                        uint32_t start, uint32_t end)
1029 {
1030         struct jffs2_full_dnode *new_fn;
1031         struct jffs2_raw_inode ri;
1032         uint32_t alloclen, phys_ofs, offset, orig_end, orig_start;
1033         int ret = 0;
1034         unsigned char *comprbuf = NULL, *writebuf;
1035         unsigned long pg;
1036         unsigned char *pg_ptr;
1037
1038         memset(&ri, 0, sizeof(ri));
1039
1040         D1(printk(KERN_DEBUG "Writing replacement dnode for ino #%u from offset 0x%x to 0x%x\n",
1041                   f->inocache->ino, start, end));
1042
1043         orig_end = end;
1044         orig_start = start;
1045
1046         if (c->nr_free_blocks + c->nr_erasing_blocks > c->resv_blocks_gcmerge) {
1047                 /* Attempt to do some merging. But only expand to cover logically
1048                    adjacent frags if the block containing them is already considered
1049                    to be dirty. Otherwise we end up with GC just going round in
1050                    circles dirtying the nodes it already wrote out, especially
1051                    on NAND where we have small eraseblocks and hence a much higher
1052                    chance of nodes having to be split to cross boundaries. */
1053
1054                 struct jffs2_node_frag *frag;
1055                 uint32_t min, max;
1056
1057                 min = start & ~(PAGE_CACHE_SIZE-1);
1058                 max = min + PAGE_CACHE_SIZE;
1059
1060                 frag = jffs2_lookup_node_frag(&f->fragtree, start);
1061
1062                 /* BUG_ON(!frag) but that'll happen anyway... */
1063
1064                 BUG_ON(frag->ofs != start);
1065
1066                 /* First grow down... */
1067                 while((frag = frag_prev(frag)) && frag->ofs >= min) {
1068
1069                         /* If the previous frag doesn't even reach the beginning, there's
1070                            excessive fragmentation. Just merge. */
1071                         if (frag->ofs > min) {
1072                                 D1(printk(KERN_DEBUG "Expanding down to cover partial frag (0x%x-0x%x)\n",
1073                                           frag->ofs, frag->ofs+frag->size));
1074                                 start = frag->ofs;
1075                                 continue;
1076                         }
1077                         /* OK. This frag holds the first byte of the page. */
1078                         if (!frag->node || !frag->node->raw) {
1079                                 D1(printk(KERN_DEBUG "First frag in page is hole (0x%x-0x%x). Not expanding down.\n",
1080                                           frag->ofs, frag->ofs+frag->size));
1081                                 break;
1082                         } else {
1083
1084                                 /* OK, it's a frag which extends to the beginning of the page. Does it live
1085                                    in a block which is still considered clean? If so, don't obsolete it.
1086                                    If not, cover it anyway. */
1087
1088                                 struct jffs2_raw_node_ref *raw = frag->node->raw;
1089                                 struct jffs2_eraseblock *jeb;
1090
1091                                 jeb = &c->blocks[raw->flash_offset / c->sector_size];
1092
1093                                 if (jeb == c->gcblock) {
1094                                         D1(printk(KERN_DEBUG "Expanding down to cover frag (0x%x-0x%x) in gcblock at %08x\n",
1095                                                   frag->ofs, frag->ofs+frag->size, ref_offset(raw)));
1096                                         start = frag->ofs;
1097                                         break;
1098                                 }
1099                                 if (!ISDIRTY(jeb->dirty_size + jeb->wasted_size)) {
1100                                         D1(printk(KERN_DEBUG "Not expanding down to cover frag (0x%x-0x%x) in clean block %08x\n",
1101                                                   frag->ofs, frag->ofs+frag->size, jeb->offset));
1102                                         break;
1103                                 }
1104
1105                                 D1(printk(KERN_DEBUG "Expanding down to cover frag (0x%x-0x%x) in dirty block %08x\n",
1106                                                   frag->ofs, frag->ofs+frag->size, jeb->offset));
1107                                 start = frag->ofs;
1108                                 break;
1109                         }
1110                 }
1111
1112                 /* ... then up */
1113
1114                 /* Find last frag which is actually part of the node we're to GC. */
1115                 frag = jffs2_lookup_node_frag(&f->fragtree, end-1);
1116
1117                 while((frag = frag_next(frag)) && frag->ofs+frag->size <= max) {
1118
1119                         /* If the previous frag doesn't even reach the beginning, there's lots
1120                            of fragmentation. Just merge. */
1121                         if (frag->ofs+frag->size < max) {
1122                                 D1(printk(KERN_DEBUG "Expanding up to cover partial frag (0x%x-0x%x)\n",
1123                                           frag->ofs, frag->ofs+frag->size));
1124                                 end = frag->ofs + frag->size;
1125                                 continue;
1126                         }
1127
1128                         if (!frag->node || !frag->node->raw) {
1129                                 D1(printk(KERN_DEBUG "Last frag in page is hole (0x%x-0x%x). Not expanding up.\n",
1130                                           frag->ofs, frag->ofs+frag->size));
1131                                 break;
1132                         } else {
1133
1134                                 /* OK, it's a frag which extends to the beginning of the page. Does it live
1135                                    in a block which is still considered clean? If so, don't obsolete it.
1136                                    If not, cover it anyway. */
1137
1138                                 struct jffs2_raw_node_ref *raw = frag->node->raw;
1139                                 struct jffs2_eraseblock *jeb;
1140
1141                                 jeb = &c->blocks[raw->flash_offset / c->sector_size];
1142
1143                                 if (jeb == c->gcblock) {
1144                                         D1(printk(KERN_DEBUG "Expanding up to cover frag (0x%x-0x%x) in gcblock at %08x\n",
1145                                                   frag->ofs, frag->ofs+frag->size, ref_offset(raw)));
1146                                         end = frag->ofs + frag->size;
1147                                         break;
1148                                 }
1149                                 if (!ISDIRTY(jeb->dirty_size + jeb->wasted_size)) {
1150                                         D1(printk(KERN_DEBUG "Not expanding up to cover frag (0x%x-0x%x) in clean block %08x\n",
1151                                                   frag->ofs, frag->ofs+frag->size, jeb->offset));
1152                                         break;
1153                                 }
1154
1155                                 D1(printk(KERN_DEBUG "Expanding up to cover frag (0x%x-0x%x) in dirty block %08x\n",
1156                                                   frag->ofs, frag->ofs+frag->size, jeb->offset));
1157                                 end = frag->ofs + frag->size;
1158                                 break;
1159                         }
1160                 }
1161                 D1(printk(KERN_DEBUG "Expanded dnode to write from (0x%x-0x%x) to (0x%x-0x%x)\n",
1162                           orig_start, orig_end, start, end));
1163
1164                 BUG_ON(end > JFFS2_F_I_SIZE(f));
1165                 BUG_ON(end < orig_end);
1166                 BUG_ON(start > orig_start);
1167         }
1168
1169         /* First, use readpage() to read the appropriate page into the page cache */
1170         /* Q: What happens if we actually try to GC the _same_ page for which commit_write()
1171          *    triggered garbage collection in the first place?
1172          * A: I _think_ it's OK. read_cache_page shouldn't deadlock, we'll write out the
1173          *    page OK. We'll actually write it out again in commit_write, which is a little
1174          *    suboptimal, but at least we're correct.
1175          */
1176         pg_ptr = jffs2_gc_fetch_page(c, f, start, &pg);
1177
1178         if (IS_ERR(pg_ptr)) {
1179                 printk(KERN_WARNING "read_cache_page() returned error: %ld\n", PTR_ERR(pg_ptr));
1180                 return PTR_ERR(pg_ptr);
1181         }
1182
1183         offset = start;
1184         while(offset < orig_end) {
1185                 uint32_t datalen;
1186                 uint32_t cdatalen;
1187                 uint16_t comprtype = JFFS2_COMPR_NONE;
1188
1189                 ret = jffs2_reserve_space_gc(c, sizeof(ri) + JFFS2_MIN_DATA_LEN, &phys_ofs, &alloclen);
1190
1191                 if (ret) {
1192                         printk(KERN_WARNING "jffs2_reserve_space_gc of %zd bytes for garbage_collect_dnode failed: %d\n",
1193                                sizeof(ri)+ JFFS2_MIN_DATA_LEN, ret);
1194                         break;
1195                 }
1196                 cdatalen = min_t(uint32_t, alloclen - sizeof(ri), end - offset);
1197                 datalen = end - offset;
1198
1199                 writebuf = pg_ptr + (offset & (PAGE_CACHE_SIZE -1));
1200
1201                 comprtype = jffs2_compress(c, f, writebuf, &comprbuf, &datalen, &cdatalen);
1202
1203                 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
1204                 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
1205                 ri.totlen = cpu_to_je32(sizeof(ri) + cdatalen);
1206                 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
1207
1208                 ri.ino = cpu_to_je32(f->inocache->ino);
1209                 ri.version = cpu_to_je32(++f->highest_version);
1210                 ri.mode = cpu_to_jemode(JFFS2_F_I_MODE(f));
1211                 ri.uid = cpu_to_je16(JFFS2_F_I_UID(f));
1212                 ri.gid = cpu_to_je16(JFFS2_F_I_GID(f));
1213                 ri.isize = cpu_to_je32(JFFS2_F_I_SIZE(f));
1214                 ri.atime = cpu_to_je32(JFFS2_F_I_ATIME(f));
1215                 ri.ctime = cpu_to_je32(JFFS2_F_I_CTIME(f));
1216                 ri.mtime = cpu_to_je32(JFFS2_F_I_MTIME(f));
1217                 ri.offset = cpu_to_je32(offset);
1218                 ri.csize = cpu_to_je32(cdatalen);
1219                 ri.dsize = cpu_to_je32(datalen);
1220                 ri.compr = comprtype & 0xff;
1221                 ri.usercompr = (comprtype >> 8) & 0xff;
1222                 ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
1223                 ri.data_crc = cpu_to_je32(crc32(0, comprbuf, cdatalen));
1224
1225                 new_fn = jffs2_write_dnode(c, f, &ri, comprbuf, cdatalen, phys_ofs, ALLOC_GC);
1226
1227                 jffs2_free_comprbuf(comprbuf, writebuf);
1228
1229                 if (IS_ERR(new_fn)) {
1230                         printk(KERN_WARNING "Error writing new dnode: %ld\n", PTR_ERR(new_fn));
1231                         ret = PTR_ERR(new_fn);
1232                         break;
1233                 }
1234                 ret = jffs2_add_full_dnode_to_inode(c, f, new_fn);
1235                 offset += datalen;
1236                 if (f->metadata) {
1237                         jffs2_mark_node_obsolete(c, f->metadata->raw);
1238                         jffs2_free_full_dnode(f->metadata);
1239                         f->metadata = NULL;
1240                 }
1241         }
1242
1243         jffs2_gc_release_page(c, pg_ptr, &pg);
1244         return ret;
1245 }
1246