fs/jffs2/gc.c

   1 /*
   2  * JFFS2 -- Journalling Flash File System, Version 2.
   3  *
   4  * Copyright © 2001-2007 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  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/mtd/mtd.h>
  14 #include <linux/slab.h>
  15 #include <linux/pagemap.h>
  16 #include <linux/crc32.h>
  17 #include <linux/compiler.h>
  18 #include <linux/stat.h>
  19 #include "nodelist.h"
  20 #include "compr.h"
  21
  22 static int jffs2_garbage_collect_pristine(struct jffs2_sb_info *c,
  23                                           struct jffs2_inode_cache *ic,
  24                                           struct jffs2_raw_node_ref *raw);
  25 static int jffs2_garbage_collect_metadata(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  26                                         struct jffs2_inode_info *f, struct jffs2_full_dnode *fd);
  27 static int jffs2_garbage_collect_dirent(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  28                                         struct jffs2_inode_info *f, struct jffs2_full_dirent *fd);
  29 static int jffs2_garbage_collect_deletion_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_hole(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  32                                       struct jffs2_inode_info *f, struct jffs2_full_dnode *fn,
  33                                       uint32_t start, uint32_t end);
  34 static int jffs2_garbage_collect_dnode(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  35                                        struct jffs2_inode_info *f, struct jffs2_full_dnode *fn,
  36                                        uint32_t start, uint32_t end);
  37 static int jffs2_garbage_collect_live(struct jffs2_sb_info *c,  struct jffs2_eraseblock *jeb,
  38                                struct jffs2_raw_node_ref *raw, struct jffs2_inode_info *f);
  39
  40 /* Called with erase_completion_lock held */
  41 static struct jffs2_eraseblock *jffs2_find_gc_block(struct jffs2_sb_info *c)
  42 {
  43         struct jffs2_eraseblock *ret;
  44         struct list_head *nextlist = NULL;
  45         int n = jiffies % 128;
  46
  47         /* Pick an eraseblock to garbage collect next. This is where we'll
  48            put the clever wear-levelling algorithms. Eventually.  */
  49         /* We possibly want to favour the dirtier blocks more when the
  50            number of free blocks is low. */
  51 again:
  52         if (!list_empty(&c->bad_used_list) && c->nr_free_blocks > c->resv_blocks_gcbad) {
  53                 D1(printk(KERN_DEBUG "Picking block from bad_used_list to GC next\n"));
  54                 nextlist = &c->bad_used_list;
  55         } else if (n < 50 && !list_empty(&c->erasable_list)) {
  56                 /* Note that most of them will have gone directly to be erased.
  57                    So don't favour the erasable_list _too_ much. */
  58                 D1(printk(KERN_DEBUG "Picking block from erasable_list to GC next\n"));
  59                 nextlist = &c->erasable_list;
  60         } else if (n < 110 && !list_empty(&c->very_dirty_list)) {
  61                 /* Most of the time, pick one off the very_dirty list */
  62                 D1(printk(KERN_DEBUG "Picking block from very_dirty_list to GC next\n"));
  63                 nextlist = &c->very_dirty_list;
  64         } else if (n < 126 && !list_empty(&c->dirty_list)) {
  65                 D1(printk(KERN_DEBUG "Picking block from dirty_list to GC next\n"));
  66                 nextlist = &c->dirty_list;
  67         } else if (!list_empty(&c->clean_list)) {
  68                 D1(printk(KERN_DEBUG "Picking block from clean_list to GC next\n"));
  69                 nextlist = &c->clean_list;
  70         } else if (!list_empty(&c->dirty_list)) {
  71                 D1(printk(KERN_DEBUG "Picking block from dirty_list to GC next (clean_list was empty)\n"));
  72
  73                 nextlist = &c->dirty_list;
  74         } else if (!list_empty(&c->very_dirty_list)) {
  75                 D1(printk(KERN_DEBUG "Picking block from very_dirty_list to GC next (clean_list and dirty_list were empty)\n"));
  76                 nextlist = &c->very_dirty_list;
  77         } else if (!list_empty(&c->erasable_list)) {
  78                 D1(printk(KERN_DEBUG "Picking block from erasable_list to GC next (clean_list and {very_,}dirty_list were empty)\n"));
  79
  80                 nextlist = &c->erasable_list;
  81         } else if (!list_empty(&c->erasable_pending_wbuf_list)) {
  82                 /* There are blocks are wating for the wbuf sync */
  83                 D1(printk(KERN_DEBUG "Synching wbuf in order to reuse erasable_pending_wbuf_list blocks\n"));
  84                 spin_unlock(&c->erase_completion_lock);
  85                 jffs2_flush_wbuf_pad(c);
  86                 spin_lock(&c->erase_completion_lock);
  87                 goto again;
  88         } else {
  89                 /* Eep. All were empty */
  90                 D1(printk(KERN_NOTICE "jffs2: No clean, dirty _or_ erasable blocks to GC from! Where are they all?\n"));
  91                 return NULL;
  92         }
  93
  94         ret = list_entry(nextlist->next, struct jffs2_eraseblock, list);
  95         list_del(&ret->list);
  96         c->gcblock = ret;
  97         ret->gc_node = ret->first_node;
  98         if (!ret->gc_node) {
  99                 printk(KERN_WARNING "Eep. ret->gc_node for block at 0x%08x is NULL\n", ret->offset);
 100                 BUG();
 101         }
 102
 103         /* Have we accidentally picked a clean block with wasted space ? */
 104         if (ret->wasted_size) {
 105                 D1(printk(KERN_DEBUG "Converting wasted_size %08x to dirty_size\n", ret->wasted_size));
 106                 ret->dirty_size += ret->wasted_size;
 107                 c->wasted_size -= ret->wasted_size;
 108                 c->dirty_size += ret->wasted_size;
 109                 ret->wasted_size = 0;
 110         }
 111
 112         return ret;
 113 }
 114
 115 /* jffs2_garbage_collect_pass
 116  * Make a single attempt to progress GC. Move one node, and possibly
 117  * start erasing one eraseblock.
 118  */
 119 int jffs2_garbage_collect_pass(struct jffs2_sb_info *c)
 120 {
 121         struct jffs2_inode_info *f;
 122         struct jffs2_inode_cache *ic;
 123         struct jffs2_eraseblock *jeb;
 124         struct jffs2_raw_node_ref *raw;
 125         uint32_t gcblock_dirty;
 126         int ret = 0, inum, nlink;
 127         int xattr = 0;
 128
 129         if (down_interruptible(&c->alloc_sem))
 130                 return -EINTR;
 131
 132         for (;;) {
 133                 spin_lock(&c->erase_completion_lock);
 134                 if (!c->unchecked_size)
 135                         break;
 136
 137                 /* We can't start doing GC yet. We haven't finished checking
 138                    the node CRCs etc. Do it now. */
 139
 140                 /* checked_ino is protected by the alloc_sem */
 141                 if (c->checked_ino > c->highest_ino && xattr) {
 142                         printk(KERN_CRIT "Checked all inodes but still 0x%x bytes of unchecked space?\n",
 143                                c->unchecked_size);
 144                         jffs2_dbg_dump_block_lists_nolock(c);
 145                         spin_unlock(&c->erase_completion_lock);
 146                         up(&c->alloc_sem);
 147                         return -ENOSPC;
 148                 }
 149
 150                 spin_unlock(&c->erase_completion_lock);
 151
 152                 if (!xattr)
 153                         xattr = jffs2_verify_xattr(c);
 154
 155                 spin_lock(&c->inocache_lock);
 156
 157                 ic = jffs2_get_ino_cache(c, c->checked_ino++);
 158
 159                 if (!ic) {
 160                         spin_unlock(&c->inocache_lock);
 161                         continue;
 162                 }
 163
 164                 if (!ic->nlink) {
 165                         D1(printk(KERN_DEBUG "Skipping check of ino #%d with nlink zero\n",
 166                                   ic->ino));
 167                         spin_unlock(&c->inocache_lock);
 168                         jffs2_xattr_delete_inode(c, ic);
 169                         continue;
 170                 }
 171                 switch(ic->state) {
 172                 case INO_STATE_CHECKEDABSENT:
 173                 case INO_STATE_PRESENT:
 174                         D1(printk(KERN_DEBUG "Skipping ino #%u already checked\n", ic->ino));
 175                         spin_unlock(&c->inocache_lock);
 176                         continue;
 177
 178                 case INO_STATE_GC:
 179                 case INO_STATE_CHECKING:
 180                         printk(KERN_WARNING "Inode #%u is in state %d during CRC check phase!\n", ic->ino, ic->state);
 181                         spin_unlock(&c->inocache_lock);
 182                         BUG();
 183
 184                 case INO_STATE_READING:
 185                         /* We need to wait for it to finish, lest we move on
 186                            and trigger the BUG() above while we haven't yet
 187                            finished checking all its nodes */
 188                         D1(printk(KERN_DEBUG "Waiting for ino #%u to finish reading\n", ic->ino));
 189                         /* We need to come back again for the _same_ inode. We've
 190                          made no progress in this case, but that should be OK */
 191                         c->checked_ino--;
 192
 193                         up(&c->alloc_sem);
 194                         sleep_on_spinunlock(&c->inocache_wq, &c->inocache_lock);
 195                         return 0;
 196
 197                 default:
 198                         BUG();
 199
 200                 case INO_STATE_UNCHECKED:
 201                         ;
 202                 }
 203                 ic->state = INO_STATE_CHECKING;
 204                 spin_unlock(&c->inocache_lock);
 205
 206                 D1(printk(KERN_DEBUG "jffs2_garbage_collect_pass() triggering inode scan of ino#%u\n", ic->ino));
 207
 208                 ret = jffs2_do_crccheck_inode(c, ic);
 209                 if (ret)
 210                         printk(KERN_WARNING "Returned error for crccheck of ino #%u. Expect badness...\n", ic->ino);
 211
 212                 jffs2_set_inocache_state(c, ic, INO_STATE_CHECKEDABSENT);
 213                 up(&c->alloc_sem);
 214                 return ret;
 215         }
 216
 217         /* First, work out which block we're garbage-collecting */
 218         jeb = c->gcblock;
 219
 220         if (!jeb)
 221                 jeb = jffs2_find_gc_block(c);
 222
 223         if (!jeb) {
 224                 D1 (printk(KERN_NOTICE "jffs2: Couldn't find erase block to garbage collect!\n"));
 225                 spin_unlock(&c->erase_completion_lock);
 226                 up(&c->alloc_sem);
 227                 return -EIO;
 228         }
 229
 230         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));
 231         D1(if (c->nextblock)
 232            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));
 233
 234         if (!jeb->used_size) {
 235                 up(&c->alloc_sem);
 236                 goto eraseit;
 237         }
 238
 239         raw = jeb->gc_node;
 240         gcblock_dirty = jeb->dirty_size;
 241
 242         while(ref_obsolete(raw)) {
 243                 D1(printk(KERN_DEBUG "Node at 0x%08x is obsolete... skipping\n", ref_offset(raw)));
 244                 raw = ref_next(raw);
 245                 if (unlikely(!raw)) {
 246                         printk(KERN_WARNING "eep. End of raw list while still supposedly nodes to GC\n");
 247                         printk(KERN_WARNING "erase block at 0x%08x. free_size 0x%08x, dirty_size 0x%08x, used_size 0x%08x\n",
 248                                jeb->offset, jeb->free_size, jeb->dirty_size, jeb->used_size);
 249                         jeb->gc_node = raw;
 250                         spin_unlock(&c->erase_completion_lock);
 251                         up(&c->alloc_sem);
 252                         BUG();
 253                 }
 254         }
 255         jeb->gc_node = raw;
 256
 257         D1(printk(KERN_DEBUG "Going to garbage collect node at 0x%08x\n", ref_offset(raw)));
 258
 259         if (!raw->next_in_ino) {
 260                 /* Inode-less node. Clean marker, snapshot or something like that */
 261                 spin_unlock(&c->erase_completion_lock);
 262                 if (ref_flags(raw) == REF_PRISTINE) {
 263                         /* It's an unknown node with JFFS2_FEATURE_RWCOMPAT_COPY */
 264                         jffs2_garbage_collect_pristine(c, NULL, raw);
 265                 } else {
 266                         /* Just mark it obsolete */
 267                         jffs2_mark_node_obsolete(c, raw);
 268                 }
 269                 up(&c->alloc_sem);
 270                 goto eraseit_lock;
 271         }
 272
 273         ic = jffs2_raw_ref_to_ic(raw);
 274
 275 #ifdef CONFIG_JFFS2_FS_XATTR
 276         /* When 'ic' refers xattr_datum/xattr_ref, this node is GCed as xattr.
 277          * We can decide whether this node is inode or xattr by ic->class.     */
 278         if (ic->class == RAWNODE_CLASS_XATTR_DATUM
 279             || ic->class == RAWNODE_CLASS_XATTR_REF) {
 280                 spin_unlock(&c->erase_completion_lock);
 281
 282                 if (ic->class == RAWNODE_CLASS_XATTR_DATUM) {
 283                         ret = jffs2_garbage_collect_xattr_datum(c, (struct jffs2_xattr_datum *)ic, raw);
 284                 } else {
 285                         ret = jffs2_garbage_collect_xattr_ref(c, (struct jffs2_xattr_ref *)ic, raw);
 286                 }
 287                 goto test_gcnode;
 288         }
 289 #endif
 290
 291         /* We need to hold the inocache. Either the erase_completion_lock or
 292            the inocache_lock are sufficient; we trade down since the inocache_lock
 293            causes less contention. */
 294         spin_lock(&c->inocache_lock);
 295
 296         spin_unlock(&c->erase_completion_lock);
 297
 298         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));
 299
 300         /* Three possibilities:
 301            1. Inode is already in-core. We must iget it and do proper
 302               updating to its fragtree, etc.
 303            2. Inode is not in-core, node is REF_PRISTINE. We lock the
 304               inocache to prevent a read_inode(), copy the node intact.
 305            3. Inode is not in-core, node is not pristine. We must iget()
 306               and take the slow path.
 307         */
 308
 309         switch(ic->state) {
 310         case INO_STATE_CHECKEDABSENT:
 311                 /* It's been checked, but it's not currently in-core.
 312                    We can just copy any pristine nodes, but have
 313                    to prevent anyone else from doing read_inode() while
 314                    we're at it, so we set the state accordingly */
 315                 if (ref_flags(raw) == REF_PRISTINE)
 316                         ic->state = INO_STATE_GC;
 317                 else {
 318                         D1(printk(KERN_DEBUG "Ino #%u is absent but node not REF_PRISTINE. Reading.\n",
 319                                   ic->ino));
 320                 }
 321                 break;
 322
 323         case INO_STATE_PRESENT:
 324                 /* It's in-core. GC must iget() it. */
 325                 break;
 326
 327         case INO_STATE_UNCHECKED:
 328         case INO_STATE_CHECKING:
 329         case INO_STATE_GC:
 330                 /* Should never happen. We should have finished checking
 331                    by the time we actually start doing any GC, and since
 332                    we're holding the alloc_sem, no other garbage collection
 333                    can happen.
 334                 */
 335                 printk(KERN_CRIT "Inode #%u already in state %d in jffs2_garbage_collect_pass()!\n",
 336                        ic->ino, ic->state);
 337                 up(&c->alloc_sem);
 338                 spin_unlock(&c->inocache_lock);
 339                 BUG();
 340
 341         case INO_STATE_READING:
 342                 /* Someone's currently trying to read it. We must wait for
 343                    them to finish and then go through the full iget() route
 344                    to do the GC. However, sometimes read_inode() needs to get
 345                    the alloc_sem() (for marking nodes invalid) so we must
 346                    drop the alloc_sem before sleeping. */
 347
 348                 up(&c->alloc_sem);
 349                 D1(printk(KERN_DEBUG "jffs2_garbage_collect_pass() waiting for ino #%u in state %d\n",
 350                           ic->ino, ic->state));
 351                 sleep_on_spinunlock(&c->inocache_wq, &c->inocache_lock);
 352                 /* And because we dropped the alloc_sem we must start again from the
 353                    beginning. Ponder chance of livelock here -- we're returning success
 354                    without actually making any progress.
 355
 356                    Q: What are the chances that the inode is back in INO_STATE_READING
 357                    again by the time we next enter this function? And that this happens
 358                    enough times to cause a real delay?
 359
 360                    A: Small enough that I don't care :)
 361                 */
 362                 return 0;
 363         }
 364
 365         /* OK. Now if the inode is in state INO_STATE_GC, we are going to copy the
 366            node intact, and we don't have to muck about with the fragtree etc.
 367            because we know it's not in-core. If it _was_ in-core, we go through
 368            all the iget() crap anyway */
 369
 370         if (ic->state == INO_STATE_GC) {
 371                 spin_unlock(&c->inocache_lock);
 372
 373                 ret = jffs2_garbage_collect_pristine(c, ic, raw);
 374
 375                 spin_lock(&c->inocache_lock);
 376                 ic->state = INO_STATE_CHECKEDABSENT;
 377                 wake_up(&c->inocache_wq);
 378
 379                 if (ret != -EBADFD) {
 380                         spin_unlock(&c->inocache_lock);
 381                         goto test_gcnode;
 382                 }
 383
 384                 /* Fall through if it wanted us to, with inocache_lock held */
 385         }
 386
 387         /* Prevent the fairly unlikely race where the gcblock is
 388            entirely obsoleted by the final close of a file which had
 389            the only valid nodes in the block, followed by erasure,
 390            followed by freeing of the ic because the erased block(s)
 391            held _all_ the nodes of that inode.... never been seen but
 392            it's vaguely possible. */
 393
 394         inum = ic->ino;
 395         nlink = ic->nlink;
 396         spin_unlock(&c->inocache_lock);
 397
 398         f = jffs2_gc_fetch_inode(c, inum, nlink);
 399         if (IS_ERR(f)) {
 400                 ret = PTR_ERR(f);
 401                 goto release_sem;
 402         }
 403         if (!f) {
 404                 ret = 0;
 405                 goto release_sem;
 406         }
 407
 408         ret = jffs2_garbage_collect_live(c, jeb, raw, f);
 409
 410         jffs2_gc_release_inode(c, f);
 411
 412  test_gcnode:
 413         if (jeb->dirty_size == gcblock_dirty && !ref_obsolete(jeb->gc_node)) {
 414                 /* Eep. This really should never happen. GC is broken */
 415                 printk(KERN_ERR "Error garbage collecting node at %08x!\n", ref_offset(jeb->gc_node));
 416                 ret = -ENOSPC;
 417         } else if (ref_offset(jeb->gc_node) == 0x1c616bdc)
 418                 printk(KERN_ERR "Wheee. Correctly GC'd node at %08x\n", ref_offset(jeb->gc_node));
 419
 420  release_sem:
 421         up(&c->alloc_sem);
 422
 423  eraseit_lock:
 424         /* If we've finished this block, start it erasing */
 425         spin_lock(&c->erase_completion_lock);
 426
 427  eraseit:
 428         if (c->gcblock && !c->gcblock->used_size) {
 429                 D1(printk(KERN_DEBUG "Block at 0x%08x completely obsoleted by GC. Moving to erase_pending_list\n", c->gcblock->offset));
 430                 /* We're GC'ing an empty block? */
 431                 list_add_tail(&c->gcblock->list, &c->erase_pending_list);
 432                 c->gcblock = NULL;
 433                 c->nr_erasing_blocks++;
 434                 jffs2_erase_pending_trigger(c);
 435         }
 436         spin_unlock(&c->erase_completion_lock);
 437
 438         return ret;
 439 }
 440
 441 static int jffs2_garbage_collect_live(struct jffs2_sb_info *c,  struct jffs2_eraseblock *jeb,
 442                                       struct jffs2_raw_node_ref *raw, struct jffs2_inode_info *f)
 443 {
 444         struct jffs2_node_frag *frag;
 445         struct jffs2_full_dnode *fn = NULL;
 446         struct jffs2_full_dirent *fd;
 447         uint32_t start = 0, end = 0, nrfrags = 0;
 448         int ret = 0;
 449
 450         down(&f->sem);
 451
 452         /* Now we have the lock for this inode. Check that it's still the one at the head
 453            of the list. */
 454
 455         spin_lock(&c->erase_completion_lock);
 456
 457         if (c->gcblock != jeb) {
 458                 spin_unlock(&c->erase_completion_lock);
 459                 D1(printk(KERN_DEBUG "GC block is no longer gcblock. Restart\n"));
 460                 goto upnout;
 461         }
 462         if (ref_obsolete(raw)) {
 463                 spin_unlock(&c->erase_completion_lock);
 464                 D1(printk(KERN_DEBUG "node to be GC'd was obsoleted in the meantime.\n"));
 465                 /* They'll call again */
 466                 goto upnout;
 467         }
 468         spin_unlock(&c->erase_completion_lock);
 469
 470         /* OK. Looks safe. And nobody can get us now because we have the semaphore. Move the block */
 471         if (f->metadata && f->metadata->raw == raw) {
 472                 fn = f->metadata;
 473                 ret = jffs2_garbage_collect_metadata(c, jeb, f, fn);
 474                 goto upnout;
 475         }
 476
 477         /* FIXME. Read node and do lookup? */
 478         for (frag = frag_first(&f->fragtree); frag; frag = frag_next(frag)) {
 479                 if (frag->node && frag->node->raw == raw) {
 480                         fn = frag->node;
 481                         end = frag->ofs + frag->size;
 482                         if (!nrfrags++)
 483                                 start = frag->ofs;
 484                         if (nrfrags == frag->node->frags)
 485                                 break; /* We've found them all */
 486                 }
 487         }
 488         if (fn) {
 489                 if (ref_flags(raw) == REF_PRISTINE) {
 490                         ret = jffs2_garbage_collect_pristine(c, f->inocache, raw);
 491                         if (!ret) {
 492                                 /* Urgh. Return it sensibly. */
 493                                 frag->node->raw = f->inocache->nodes;
 494                         }
 495                         if (ret != -EBADFD)
 496                                 goto upnout;
 497                 }
 498                 /* We found a datanode. Do the GC */
 499                 if((start >> PAGE_CACHE_SHIFT) < ((end-1) >> PAGE_CACHE_SHIFT)) {
 500                         /* It crosses a page boundary. Therefore, it must be a hole. */
 501                         ret = jffs2_garbage_collect_hole(c, jeb, f, fn, start, end);
 502                 } else {
 503                         /* It could still be a hole. But we GC the page this way anyway */
 504                         ret = jffs2_garbage_collect_dnode(c, jeb, f, fn, start, end);
 505                 }
 506                 goto upnout;
 507         }
 508
 509         /* Wasn't a dnode. Try dirent */
 510         for (fd = f->dents; fd; fd=fd->next) {
 511                 if (fd->raw == raw)
 512                         break;
 513         }
 514
 515         if (fd && fd->ino) {
 516                 ret = jffs2_garbage_collect_dirent(c, jeb, f, fd);
 517         } else if (fd) {
 518                 ret = jffs2_garbage_collect_deletion_dirent(c, jeb, f, fd);
 519         } else {
 520                 printk(KERN_WARNING "Raw node at 0x%08x wasn't in node lists for ino #%u\n",
 521                        ref_offset(raw), f->inocache->ino);
 522                 if (ref_obsolete(raw)) {
 523                         printk(KERN_WARNING "But it's obsolete so we don't mind too much\n");
 524                 } else {
 525                         jffs2_dbg_dump_node(c, ref_offset(raw));
 526                         BUG();
 527                 }
 528         }
 529  upnout:
 530         up(&f->sem);
 531
 532         return ret;
 533 }
 534
 535 static int jffs2_garbage_collect_pristine(struct jffs2_sb_info *c,
 536                                           struct jffs2_inode_cache *ic,
 537                                           struct jffs2_raw_node_ref *raw)
 538 {
 539         union jffs2_node_union *node;
 540         size_t retlen;
 541         int ret;
 542         uint32_t phys_ofs, alloclen;
 543         uint32_t crc, rawlen;
 544         int retried = 0;
 545
 546         D1(printk(KERN_DEBUG "Going to GC REF_PRISTINE node at 0x%08x\n", ref_offset(raw)));
 547
 548         alloclen = rawlen = ref_totlen(c, c->gcblock, raw);
 549
 550         /* Ask for a small amount of space (or the totlen if smaller) because we
 551            don't want to force wastage of the end of a block if splitting would
 552            work. */
 553         if (ic && alloclen > sizeof(struct jffs2_raw_inode) + JFFS2_MIN_DATA_LEN)
 554                 alloclen = sizeof(struct jffs2_raw_inode) + JFFS2_MIN_DATA_LEN;
 555
 556         ret = jffs2_reserve_space_gc(c, alloclen, &alloclen, rawlen);
 557         /* 'rawlen' is not the exact summary size; it is only an upper estimation */
 558
 559         if (ret)
 560                 return ret;
 561
 562         if (alloclen < rawlen) {
 563                 /* Doesn't fit untouched. We'll go the old route and split it */
 564                 return -EBADFD;
 565         }
 566
 567         node = kmalloc(rawlen, GFP_KERNEL);
 568         if (!node)
 569                 return -ENOMEM;
 570
 571         ret = jffs2_flash_read(c, ref_offset(raw), rawlen, &retlen, (char *)node);
 572         if (!ret && retlen != rawlen)
 573                 ret = -EIO;
 574         if (ret)
 575                 goto out_node;
 576
 577         crc = crc32(0, node, sizeof(struct jffs2_unknown_node)-4);
 578         if (je32_to_cpu(node->u.hdr_crc) != crc) {
 579                 printk(KERN_WARNING "Header CRC failed on REF_PRISTINE node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 580                        ref_offset(raw), je32_to_cpu(node->u.hdr_crc), crc);
 581                 goto bail;
 582         }
 583
 584         switch(je16_to_cpu(node->u.nodetype)) {
 585         case JFFS2_NODETYPE_INODE:
 586                 crc = crc32(0, node, sizeof(node->i)-8);
 587                 if (je32_to_cpu(node->i.node_crc) != crc) {
 588                         printk(KERN_WARNING "Node CRC failed on REF_PRISTINE data node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 589                                ref_offset(raw), je32_to_cpu(node->i.node_crc), crc);
 590                         goto bail;
 591                 }
 592
 593                 if (je32_to_cpu(node->i.dsize)) {
 594                         crc = crc32(0, node->i.data, je32_to_cpu(node->i.csize));
 595                         if (je32_to_cpu(node->i.data_crc) != crc) {
 596                                 printk(KERN_WARNING "Data CRC failed on REF_PRISTINE data node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 597                                        ref_offset(raw), je32_to_cpu(node->i.data_crc), crc);
 598                                 goto bail;
 599                         }
 600                 }
 601                 break;
 602
 603         case JFFS2_NODETYPE_DIRENT:
 604                 crc = crc32(0, node, sizeof(node->d)-8);
 605                 if (je32_to_cpu(node->d.node_crc) != crc) {
 606                         printk(KERN_WARNING "Node CRC failed on REF_PRISTINE dirent node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 607                                ref_offset(raw), je32_to_cpu(node->d.node_crc), crc);
 608                         goto bail;
 609                 }
 610
 611                 if (strnlen(node->d.name, node->d.nsize) != node->d.nsize) {
 612                         printk(KERN_WARNING "Name in dirent node at 0x%08x contains zeroes\n", ref_offset(raw));
 613                         goto bail;
 614                 }
 615
 616                 if (node->d.nsize) {
 617                         crc = crc32(0, node->d.name, node->d.nsize);
 618                         if (je32_to_cpu(node->d.name_crc) != crc) {
 619                                 printk(KERN_WARNING "Name CRC failed on REF_PRISTINE dirent node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
 620                                        ref_offset(raw), je32_to_cpu(node->d.name_crc), crc);
 621                                 goto bail;
 622                         }
 623                 }
 624                 break;
 625         default:
 626                 /* If it's inode-less, we don't _know_ what it is. Just copy it intact */
 627                 if (ic) {
 628                         printk(KERN_WARNING "Unknown node type for REF_PRISTINE node at 0x%08x: 0x%04x\n",
 629                                ref_offset(raw), je16_to_cpu(node->u.nodetype));
 630                         goto bail;
 631                 }
 632         }
 633
 634         /* OK, all the CRCs are good; this node can just be copied as-is. */
 635  retry:
 636         phys_ofs = write_ofs(c);
 637
 638         ret = jffs2_flash_write(c, phys_ofs, rawlen, &retlen, (char *)node);
 639
 640         if (ret || (retlen != rawlen)) {
 641                 printk(KERN_NOTICE "Write of %d bytes at 0x%08x failed. returned %d, retlen %zd\n",
 642                        rawlen, phys_ofs, ret, retlen);
 643                 if (retlen) {
 644                         jffs2_add_physical_node_ref(c, phys_ofs | REF_OBSOLETE, rawlen, NULL);
 645                 } else {
 646                         printk(KERN_NOTICE "Not marking the space at 0x%08x as dirty because the flash driver returned retlen zero\n", phys_ofs);
 647                 }
 648                 if (!retried) {
 649                         /* Try to reallocate space and retry */
 650                         uint32_t dummy;
 651                         struct jffs2_eraseblock *jeb = &c->blocks[phys_ofs / c->sector_size];
 652
 653                         retried = 1;
 654
 655                         D1(printk(KERN_DEBUG "Retrying failed write of REF_PRISTINE node.\n"));
 656
 657                         jffs2_dbg_acct_sanity_check(c,jeb);
 658                         jffs2_dbg_acct_paranoia_check(c, jeb);
 659
 660                         ret = jffs2_reserve_space_gc(c, rawlen, &dummy, rawlen);
 661                                                 /* this is not the exact summary size of it,
 662                                                         it is only an upper estimation */
 663
 664                         if (!ret) {
 665                                 D1(printk(KERN_DEBUG "Allocated space at 0x%08x to retry failed write.\n", phys_ofs));
 666
 667                                 jffs2_dbg_acct_sanity_check(c,jeb);
 668                                 jffs2_dbg_acct_paranoia_check(c, jeb);
 669
 670                                 goto retry;
 671                         }
 672                         D1(printk(KERN_DEBUG "Failed to allocate space to retry failed write: %d!\n", ret));
 673                 }
 674
 675                 if (!ret)
 676                         ret = -EIO;
 677                 goto out_node;
 678         }
 679         jffs2_add_physical_node_ref(c, phys_ofs | REF_PRISTINE, rawlen, ic);
 680
 681         jffs2_mark_node_obsolete(c, raw);
 682         D1(printk(KERN_DEBUG "WHEEE! GC REF_PRISTINE node at 0x%08x succeeded\n", ref_offset(raw)));
 683
 684  out_node:
 685         kfree(node);
 686         return ret;
 687  bail:
 688         ret = -EBADFD;
 689         goto out_node;
 690 }
 691
 692 static int jffs2_garbage_collect_metadata(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 693                                         struct jffs2_inode_info *f, struct jffs2_full_dnode *fn)
 694 {
 695         struct jffs2_full_dnode *new_fn;
 696         struct jffs2_raw_inode ri;
 697         struct jffs2_node_frag *last_frag;
 698         union jffs2_device_node dev;
 699         char *mdata = NULL, mdatalen = 0;
 700         uint32_t alloclen, ilen;
 701         int ret;
 702
 703         if (S_ISBLK(JFFS2_F_I_MODE(f)) ||
 704             S_ISCHR(JFFS2_F_I_MODE(f)) ) {
 705                 /* For these, we don't actually need to read the old node */
 706                 mdatalen = jffs2_encode_dev(&dev, JFFS2_F_I_RDEV(f));
 707                 mdata = (char *)&dev;
 708                 D1(printk(KERN_DEBUG "jffs2_garbage_collect_metadata(): Writing %d bytes of kdev_t\n", mdatalen));
 709         } else if (S_ISLNK(JFFS2_F_I_MODE(f))) {
 710                 mdatalen = fn->size;
 711                 mdata = kmalloc(fn->size, GFP_KERNEL);
 712                 if (!mdata) {
 713                         printk(KERN_WARNING "kmalloc of mdata failed in jffs2_garbage_collect_metadata()\n");
 714                         return -ENOMEM;
 715                 }
 716                 ret = jffs2_read_dnode(c, f, fn, mdata, 0, mdatalen);
 717                 if (ret) {
 718                         printk(KERN_WARNING "read of old metadata failed in jffs2_garbage_collect_metadata(): %d\n", ret);
 719                         kfree(mdata);
 720                         return ret;
 721                 }
 722                 D1(printk(KERN_DEBUG "jffs2_garbage_collect_metadata(): Writing %d bites of symlink target\n", mdatalen));
 723
 724         }
 725
 726         ret = jffs2_reserve_space_gc(c, sizeof(ri) + mdatalen, &alloclen,
 727                                 JFFS2_SUMMARY_INODE_SIZE);
 728         if (ret) {
 729                 printk(KERN_WARNING "jffs2_reserve_space_gc of %zd bytes for garbage_collect_metadata failed: %d\n",
 730                        sizeof(ri)+ mdatalen, ret);
 731                 goto out;
 732         }
 733
 734         last_frag = frag_last(&f->fragtree);
 735         if (last_frag)
 736                 /* Fetch the inode length from the fragtree rather then
 737                  * from i_size since i_size may have not been updated yet */
 738                 ilen = last_frag->ofs + last_frag->size;
 739         else
 740                 ilen = JFFS2_F_I_SIZE(f);
 741
 742         memset(&ri, 0, sizeof(ri));
 743         ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
 744         ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
 745         ri.totlen = cpu_to_je32(sizeof(ri) + mdatalen);
 746         ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
 747
 748         ri.ino = cpu_to_je32(f->inocache->ino);
 749         ri.version = cpu_to_je32(++f->highest_version);
 750         ri.mode = cpu_to_jemode(JFFS2_F_I_MODE(f));
 751         ri.uid = cpu_to_je16(JFFS2_F_I_UID(f));
 752         ri.gid = cpu_to_je16(JFFS2_F_I_GID(f));
 753         ri.isize = cpu_to_je32(ilen);
 754         ri.atime = cpu_to_je32(JFFS2_F_I_ATIME(f));
 755         ri.ctime = cpu_to_je32(JFFS2_F_I_CTIME(f));
 756         ri.mtime = cpu_to_je32(JFFS2_F_I_MTIME(f));
 757         ri.offset = cpu_to_je32(0);
 758         ri.csize = cpu_to_je32(mdatalen);
 759         ri.dsize = cpu_to_je32(mdatalen);
 760         ri.compr = JFFS2_COMPR_NONE;
 761         ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
 762         ri.data_crc = cpu_to_je32(crc32(0, mdata, mdatalen));
 763
 764         new_fn = jffs2_write_dnode(c, f, &ri, mdata, mdatalen, ALLOC_GC);
 765
 766         if (IS_ERR(new_fn)) {
 767                 printk(KERN_WARNING "Error writing new dnode: %ld\n", PTR_ERR(new_fn));
 768                 ret = PTR_ERR(new_fn);
 769                 goto out;
 770         }
 771         jffs2_mark_node_obsolete(c, fn->raw);
 772         jffs2_free_full_dnode(fn);
 773         f->metadata = new_fn;
 774  out:
 775         if (S_ISLNK(JFFS2_F_I_MODE(f)))
 776                 kfree(mdata);
 777         return ret;
 778 }
 779
 780 static int jffs2_garbage_collect_dirent(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 781                                         struct jffs2_inode_info *f, struct jffs2_full_dirent *fd)
 782 {
 783         struct jffs2_full_dirent *new_fd;
 784         struct jffs2_raw_dirent rd;
 785         uint32_t alloclen;
 786         int ret;
 787
 788         rd.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
 789         rd.nodetype = cpu_to_je16(JFFS2_NODETYPE_DIRENT);
 790         rd.nsize = strlen(fd->name);
 791         rd.totlen = cpu_to_je32(sizeof(rd) + rd.nsize);
 792         rd.hdr_crc = cpu_to_je32(crc32(0, &rd, sizeof(struct jffs2_unknown_node)-4));
 793
 794         rd.pino = cpu_to_je32(f->inocache->ino);
 795         rd.version = cpu_to_je32(++f->highest_version);
 796         rd.ino = cpu_to_je32(fd->ino);
 797         /* If the times on this inode were set by explicit utime() they can be different,
 798            so refrain from splatting them. */
 799         if (JFFS2_F_I_MTIME(f) == JFFS2_F_I_CTIME(f))
 800                 rd.mctime = cpu_to_je32(JFFS2_F_I_MTIME(f));
 801         else
 802                 rd.mctime = cpu_to_je32(0);
 803         rd.type = fd->type;
 804         rd.node_crc = cpu_to_je32(crc32(0, &rd, sizeof(rd)-8));
 805         rd.name_crc = cpu_to_je32(crc32(0, fd->name, rd.nsize));
 806
 807         ret = jffs2_reserve_space_gc(c, sizeof(rd)+rd.nsize, &alloclen,
 808                                 JFFS2_SUMMARY_DIRENT_SIZE(rd.nsize));
 809         if (ret) {
 810                 printk(KERN_WARNING "jffs2_reserve_space_gc of %zd bytes for garbage_collect_dirent failed: %d\n",
 811                        sizeof(rd)+rd.nsize, ret);
 812                 return ret;
 813         }
 814         new_fd = jffs2_write_dirent(c, f, &rd, fd->name, rd.nsize, ALLOC_GC);
 815
 816         if (IS_ERR(new_fd)) {
 817                 printk(KERN_WARNING "jffs2_write_dirent in garbage_collect_dirent failed: %ld\n", PTR_ERR(new_fd));
 818                 return PTR_ERR(new_fd);
 819         }
 820         jffs2_add_fd_to_list(c, new_fd, &f->dents);
 821         return 0;
 822 }
 823
 824 static int jffs2_garbage_collect_deletion_dirent(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 825                                         struct jffs2_inode_info *f, struct jffs2_full_dirent *fd)
 826 {
 827         struct jffs2_full_dirent **fdp = &f->dents;
 828         int found = 0;
 829
 830         /* On a medium where we can't actually mark nodes obsolete
 831            pernamently, such as NAND flash, we need to work out
 832            whether this deletion dirent is still needed to actively
 833            delete a 'real' dirent with the same name that's still
 834            somewhere else on the flash. */
 835         if (!jffs2_can_mark_obsolete(c)) {
 836                 struct jffs2_raw_dirent *rd;
 837                 struct jffs2_raw_node_ref *raw;
 838                 int ret;
 839                 size_t retlen;
 840                 int name_len = strlen(fd->name);
 841                 uint32_t name_crc = crc32(0, fd->name, name_len);
 842                 uint32_t rawlen = ref_totlen(c, jeb, fd->raw);
 843
 844                 rd = kmalloc(rawlen, GFP_KERNEL);
 845                 if (!rd)
 846                         return -ENOMEM;
 847
 848                 /* Prevent the erase code from nicking the obsolete node refs while
 849                    we're looking at them. I really don't like this extra lock but
 850                    can't see any alternative. Suggestions on a postcard to... */
 851                 down(&c->erase_free_sem);
 852
 853                 for (raw = f->inocache->nodes; raw != (void *)f->inocache; raw = raw->next_in_ino) {
 854
 855                         cond_resched();
 856
 857                         /* We only care about obsolete ones */
 858                         if (!(ref_obsolete(raw)))
 859                                 continue;
 860
 861                         /* Any dirent with the same name is going to have the same length... */
 862                         if (ref_totlen(c, NULL, raw) != rawlen)
 863                                 continue;
 864
 865                         /* Doesn't matter if there's one in the same erase block. We're going to
 866                            delete it too at the same time. */
 867                         if (SECTOR_ADDR(raw->flash_offset) == SECTOR_ADDR(fd->raw->flash_offset))
 868                                 continue;
 869
 870                         D1(printk(KERN_DEBUG "Check potential deletion dirent at %08x\n", ref_offset(raw)));
 871
 872                         /* This is an obsolete node belonging to the same directory, and it's of the right
 873                            length. We need to take a closer look...*/
 874                         ret = jffs2_flash_read(c, ref_offset(raw), rawlen, &retlen, (char *)rd);
 875                         if (ret) {
 876                                 printk(KERN_WARNING "jffs2_g_c_deletion_dirent(): Read error (%d) reading obsolete node at %08x\n", ret, ref_offset(raw));
 877                                 /* If we can't read it, we don't need to continue to obsolete it. Continue */
 878                                 continue;
 879                         }
 880                         if (retlen != rawlen) {
 881                                 printk(KERN_WARNING "jffs2_g_c_deletion_dirent(): Short read (%zd not %u) reading header from obsolete node at %08x\n",
 882                                        retlen, rawlen, ref_offset(raw));
 883                                 continue;
 884                         }
 885
 886                         if (je16_to_cpu(rd->nodetype) != JFFS2_NODETYPE_DIRENT)
 887                                 continue;
 888
 889                         /* If the name CRC doesn't match, skip */
 890                         if (je32_to_cpu(rd->name_crc) != name_crc)
 891                                 continue;
 892
 893                         /* If the name length doesn't match, or it's another deletion dirent, skip */
 894                         if (rd->nsize != name_len || !je32_to_cpu(rd->ino))
 895                                 continue;
 896
 897                         /* OK, check the actual name now */
 898                         if (memcmp(rd->name, fd->name, name_len))
 899                                 continue;
 900
 901                         /* OK. The name really does match. There really is still an older node on
 902                            the flash which our deletion dirent obsoletes. So we have to write out
 903                            a new deletion dirent to replace it */
 904                         up(&c->erase_free_sem);
 905
 906                         D1(printk(KERN_DEBUG "Deletion dirent at %08x still obsoletes real dirent \"%s\" at %08x for ino #%u\n",
 907                                   ref_offset(fd->raw), fd->name, ref_offset(raw), je32_to_cpu(rd->ino)));
 908                         kfree(rd);
 909
 910                         return jffs2_garbage_collect_dirent(c, jeb, f, fd);
 911                 }
 912
 913                 up(&c->erase_free_sem);
 914                 kfree(rd);
 915         }
 916
 917         /* FIXME: If we're deleting a dirent which contains the current mtime and ctime,
 918            we should update the metadata node with those times accordingly */
 919
 920         /* No need for it any more. Just mark it obsolete and remove it from the list */
 921         while (*fdp) {
 922                 if ((*fdp) == fd) {
 923                         found = 1;
 924                         *fdp = fd->next;
 925                         break;
 926                 }
 927                 fdp = &(*fdp)->next;
 928         }
 929         if (!found) {
 930                 printk(KERN_WARNING "Deletion dirent \"%s\" not found in list for ino #%u\n", fd->name, f->inocache->ino);
 931         }
 932         jffs2_mark_node_obsolete(c, fd->raw);
 933         jffs2_free_full_dirent(fd);
 934         return 0;
 935 }
 936
 937 static int jffs2_garbage_collect_hole(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 938                                       struct jffs2_inode_info *f, struct jffs2_full_dnode *fn,
 939                                       uint32_t start, uint32_t end)
 940 {
 941         struct jffs2_raw_inode ri;
 942         struct jffs2_node_frag *frag;
 943         struct jffs2_full_dnode *new_fn;
 944         uint32_t alloclen, ilen;
 945         int ret;
 946
 947         D1(printk(KERN_DEBUG "Writing replacement hole node for ino #%u from offset 0x%x to 0x%x\n",
 948                   f->inocache->ino, start, end));
 949
 950         memset(&ri, 0, sizeof(ri));
 951
 952         if(fn->frags > 1) {
 953                 size_t readlen;
 954                 uint32_t crc;
 955                 /* It's partially obsoleted by a later write. So we have to
 956                    write it out again with the _same_ version as before */
 957                 ret = jffs2_flash_read(c, ref_offset(fn->raw), sizeof(ri), &readlen, (char *)&ri);
 958                 if (readlen != sizeof(ri) || ret) {
 959                         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);
 960                         goto fill;
 961                 }
 962                 if (je16_to_cpu(ri.nodetype) != JFFS2_NODETYPE_INODE) {
 963                         printk(KERN_WARNING "jffs2_garbage_collect_hole: Node at 0x%08x had node type 0x%04x instead of JFFS2_NODETYPE_INODE(0x%04x)\n",
 964                                ref_offset(fn->raw),
 965                                je16_to_cpu(ri.nodetype), JFFS2_NODETYPE_INODE);
 966                         return -EIO;
 967                 }
 968                 if (je32_to_cpu(ri.totlen) != sizeof(ri)) {
 969                         printk(KERN_WARNING "jffs2_garbage_collect_hole: Node at 0x%08x had totlen 0x%x instead of expected 0x%zx\n",
 970                                ref_offset(fn->raw),
 971                                je32_to_cpu(ri.totlen), sizeof(ri));
 972                         return -EIO;
 973                 }
 974                 crc = crc32(0, &ri, sizeof(ri)-8);
 975                 if (crc != je32_to_cpu(ri.node_crc)) {
 976                         printk(KERN_WARNING "jffs2_garbage_collect_hole: Node at 0x%08x had CRC 0x%08x which doesn't match calculated CRC 0x%08x\n",
 977                                ref_offset(fn->raw),
 978                                je32_to_cpu(ri.node_crc), crc);
 979                         /* FIXME: We could possibly deal with this by writing new holes for each frag */
 980                         printk(KERN_WARNING "Data in the range 0x%08x to 0x%08x of inode #%u will be lost\n",
 981                                start, end, f->inocache->ino);
 982                         goto fill;
 983                 }
 984                 if (ri.compr != JFFS2_COMPR_ZERO) {
 985                         printk(KERN_WARNING "jffs2_garbage_collect_hole: Node 0x%08x wasn't a hole node!\n", ref_offset(fn->raw));
 986                         printk(KERN_WARNING "Data in the range 0x%08x to 0x%08x of inode #%u will be lost\n",
 987                                start, end, f->inocache->ino);
 988                         goto fill;
 989                 }
 990         } else {
 991         fill:
 992                 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
 993                 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
 994                 ri.totlen = cpu_to_je32(sizeof(ri));
 995                 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
 996
 997                 ri.ino = cpu_to_je32(f->inocache->ino);
 998                 ri.version = cpu_to_je32(++f->highest_version);
 999                 ri.offset = cpu_to_je32(start);
1000                 ri.dsize = cpu_to_je32(end - start);
1001                 ri.csize = cpu_to_je32(0);
1002                 ri.compr = JFFS2_COMPR_ZERO;
1003         }
1004
1005         frag = frag_last(&f->fragtree);
1006         if (frag)
1007                 /* Fetch the inode length from the fragtree rather then
1008                  * from i_size since i_size may have not been updated yet */
1009                 ilen = frag->ofs + frag->size;
1010         else
1011                 ilen = JFFS2_F_I_SIZE(f);
1012
1013         ri.mode = cpu_to_jemode(JFFS2_F_I_MODE(f));
1014         ri.uid = cpu_to_je16(JFFS2_F_I_UID(f));
1015         ri.gid = cpu_to_je16(JFFS2_F_I_GID(f));
1016         ri.isize = cpu_to_je32(ilen);
1017         ri.atime = cpu_to_je32(JFFS2_F_I_ATIME(f));
1018         ri.ctime = cpu_to_je32(JFFS2_F_I_CTIME(f));
1019         ri.mtime = cpu_to_je32(JFFS2_F_I_MTIME(f));
1020         ri.data_crc = cpu_to_je32(0);
1021         ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
1022
1023         ret = jffs2_reserve_space_gc(c, sizeof(ri), &alloclen,
1024                                      JFFS2_SUMMARY_INODE_SIZE);
1025         if (ret) {
1026                 printk(KERN_WARNING "jffs2_reserve_space_gc of %zd bytes for garbage_collect_hole failed: %d\n",
1027                        sizeof(ri), ret);
1028                 return ret;
1029         }
1030         new_fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_GC);
1031
1032         if (IS_ERR(new_fn)) {
1033                 printk(KERN_WARNING "Error writing new hole node: %ld\n", PTR_ERR(new_fn));
1034                 return PTR_ERR(new_fn);
1035         }
1036         if (je32_to_cpu(ri.version) == f->highest_version) {
1037                 jffs2_add_full_dnode_to_inode(c, f, new_fn);
1038                 if (f->metadata) {
1039                         jffs2_mark_node_obsolete(c, f->metadata->raw);
1040                         jffs2_free_full_dnode(f->metadata);
1041                         f->metadata = NULL;
1042                 }
1043                 return 0;
1044         }
1045
1046         /*
1047          * We should only get here in the case where the node we are
1048          * replacing had more than one frag, so we kept the same version
1049          * number as before. (Except in case of error -- see 'goto fill;'
1050          * above.)
1051          */
1052         D1(if(unlikely(fn->frags <= 1)) {
1053                 printk(KERN_WARNING "jffs2_garbage_collect_hole: Replacing fn with %d frag(s) but new ver %d != highest_version %d of ino #%d\n",
1054                        fn->frags, je32_to_cpu(ri.version), f->highest_version,
1055                        je32_to_cpu(ri.ino));
1056         });
1057
1058         /* This is a partially-overlapped hole node. Mark it REF_NORMAL not REF_PRISTINE */
1059         mark_ref_normal(new_fn->raw);
1060
1061         for (frag = jffs2_lookup_node_frag(&f->fragtree, fn->ofs);
1062              frag; frag = frag_next(frag)) {
1063                 if (frag->ofs > fn->size + fn->ofs)
1064                         break;
1065                 if (frag->node == fn) {
1066                         frag->node = new_fn;
1067                         new_fn->frags++;
1068                         fn->frags--;
1069                 }
1070         }
1071         if (fn->frags) {
1072                 printk(KERN_WARNING "jffs2_garbage_collect_hole: Old node still has frags!\n");
1073                 BUG();
1074         }
1075         if (!new_fn->frags) {
1076                 printk(KERN_WARNING "jffs2_garbage_collect_hole: New node has no frags!\n");
1077                 BUG();
1078         }
1079
1080         jffs2_mark_node_obsolete(c, fn->raw);
1081         jffs2_free_full_dnode(fn);
1082
1083         return 0;
1084 }
1085
1086 static int jffs2_garbage_collect_dnode(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
1087                                        struct jffs2_inode_info *f, struct jffs2_full_dnode *fn,
1088                                        uint32_t start, uint32_t end)
1089 {
1090         struct jffs2_full_dnode *new_fn;
1091         struct jffs2_raw_inode ri;
1092         uint32_t alloclen, offset, orig_end, orig_start;
1093         int ret = 0;
1094         unsigned char *comprbuf = NULL, *writebuf;
1095         unsigned long pg;
1096         unsigned char *pg_ptr;
1097
1098         memset(&ri, 0, sizeof(ri));
1099
1100         D1(printk(KERN_DEBUG "Writing replacement dnode for ino #%u from offset 0x%x to 0x%x\n",
1101                   f->inocache->ino, start, end));
1102
1103         orig_end = end;
1104         orig_start = start;
1105
1106         if (c->nr_free_blocks + c->nr_erasing_blocks > c->resv_blocks_gcmerge) {
1107                 /* Attempt to do some merging. But only expand to cover logically
1108                    adjacent frags if the block containing them is already considered
1109                    to be dirty. Otherwise we end up with GC just going round in
1110                    circles dirtying the nodes it already wrote out, especially
1111                    on NAND where we have small eraseblocks and hence a much higher
1112                    chance of nodes having to be split to cross boundaries. */
1113
1114                 struct jffs2_node_frag *frag;
1115                 uint32_t min, max;
1116
1117                 min = start & ~(PAGE_CACHE_SIZE-1);
1118                 max = min + PAGE_CACHE_SIZE;
1119
1120                 frag = jffs2_lookup_node_frag(&f->fragtree, start);
1121
1122                 /* BUG_ON(!frag) but that'll happen anyway... */
1123
1124                 BUG_ON(frag->ofs != start);
1125
1126                 /* First grow down... */
1127                 while((frag = frag_prev(frag)) && frag->ofs >= min) {
1128
1129                         /* If the previous frag doesn't even reach the beginning, there's
1130                            excessive fragmentation. Just merge. */
1131                         if (frag->ofs > min) {
1132                                 D1(printk(KERN_DEBUG "Expanding down to cover partial frag (0x%x-0x%x)\n",
1133                                           frag->ofs, frag->ofs+frag->size));
1134                                 start = frag->ofs;
1135                                 continue;
1136                         }
1137                         /* OK. This frag holds the first byte of the page. */
1138                         if (!frag->node || !frag->node->raw) {
1139                                 D1(printk(KERN_DEBUG "First frag in page is hole (0x%x-0x%x). Not expanding down.\n",
1140                                           frag->ofs, frag->ofs+frag->size));
1141                                 break;
1142                         } else {
1143
1144                                 /* OK, it's a frag which extends to the beginning of the page. Does it live
1145                                    in a block which is still considered clean? If so, don't obsolete it.
1146                                    If not, cover it anyway. */
1147
1148                                 struct jffs2_raw_node_ref *raw = frag->node->raw;
1149                                 struct jffs2_eraseblock *jeb;
1150
1151                                 jeb = &c->blocks[raw->flash_offset / c->sector_size];
1152
1153                                 if (jeb == c->gcblock) {
1154                                         D1(printk(KERN_DEBUG "Expanding down to cover frag (0x%x-0x%x) in gcblock at %08x\n",
1155                                                   frag->ofs, frag->ofs+frag->size, ref_offset(raw)));
1156                                         start = frag->ofs;
1157                                         break;
1158                                 }
1159                                 if (!ISDIRTY(jeb->dirty_size + jeb->wasted_size)) {
1160                                         D1(printk(KERN_DEBUG "Not expanding down to cover frag (0x%x-0x%x) in clean block %08x\n",
1161                                                   frag->ofs, frag->ofs+frag->size, jeb->offset));
1162                                         break;
1163                                 }
1164
1165                                 D1(printk(KERN_DEBUG "Expanding down to cover frag (0x%x-0x%x) in dirty block %08x\n",
1166                                                   frag->ofs, frag->ofs+frag->size, jeb->offset));
1167                                 start = frag->ofs;
1168                                 break;
1169                         }
1170                 }
1171
1172                 /* ... then up */
1173
1174                 /* Find last frag which is actually part of the node we're to GC. */
1175                 frag = jffs2_lookup_node_frag(&f->fragtree, end-1);
1176
1177                 while((frag = frag_next(frag)) && frag->ofs+frag->size <= max) {
1178
1179                         /* If the previous frag doesn't even reach the beginning, there's lots
1180                            of fragmentation. Just merge. */
1181                         if (frag->ofs+frag->size < max) {
1182                                 D1(printk(KERN_DEBUG "Expanding up to cover partial frag (0x%x-0x%x)\n",
1183                                           frag->ofs, frag->ofs+frag->size));
1184                                 end = frag->ofs + frag->size;
1185                                 continue;
1186                         }
1187
1188                         if (!frag->node || !frag->node->raw) {
1189                                 D1(printk(KERN_DEBUG "Last frag in page is hole (0x%x-0x%x). Not expanding up.\n",
1190                                           frag->ofs, frag->ofs+frag->size));
1191                                 break;
1192                         } else {
1193
1194                                 /* OK, it's a frag which extends to the beginning of the page. Does it live
1195                                    in a block which is still considered clean? If so, don't obsolete it.
1196                                    If not, cover it anyway. */
1197
1198                                 struct jffs2_raw_node_ref *raw = frag->node->raw;
1199                                 struct jffs2_eraseblock *jeb;
1200
1201                                 jeb = &c->blocks[raw->flash_offset / c->sector_size];
1202
1203                                 if (jeb == c->gcblock) {
1204                                         D1(printk(KERN_DEBUG "Expanding up to cover frag (0x%x-0x%x) in gcblock at %08x\n",
1205                                                   frag->ofs, frag->ofs+frag->size, ref_offset(raw)));
1206                                         end = frag->ofs + frag->size;
1207                                         break;
1208                                 }
1209                                 if (!ISDIRTY(jeb->dirty_size + jeb->wasted_size)) {
1210                                         D1(printk(KERN_DEBUG "Not expanding up to cover frag (0x%x-0x%x) in clean block %08x\n",
1211                                                   frag->ofs, frag->ofs+frag->size, jeb->offset));
1212                                         break;
1213                                 }
1214
1215                                 D1(printk(KERN_DEBUG "Expanding up to cover frag (0x%x-0x%x) in dirty block %08x\n",
1216                                                   frag->ofs, frag->ofs+frag->size, jeb->offset));
1217                                 end = frag->ofs + frag->size;
1218                                 break;
1219                         }
1220                 }
1221                 D1(printk(KERN_DEBUG "Expanded dnode to write from (0x%x-0x%x) to (0x%x-0x%x)\n",
1222                           orig_start, orig_end, start, end));
1223
1224                 D1(BUG_ON(end > frag_last(&f->fragtree)->ofs + frag_last(&f->fragtree)->size));
1225                 BUG_ON(end < orig_end);
1226                 BUG_ON(start > orig_start);
1227         }
1228
1229         /* First, use readpage() to read the appropriate page into the page cache */
1230         /* Q: What happens if we actually try to GC the _same_ page for which commit_write()
1231          *    triggered garbage collection in the first place?
1232          * A: I _think_ it's OK. read_cache_page shouldn't deadlock, we'll write out the
1233          *    page OK. We'll actually write it out again in commit_write, which is a little
1234          *    suboptimal, but at least we're correct.
1235          */
1236         pg_ptr = jffs2_gc_fetch_page(c, f, start, &pg);
1237
1238         if (IS_ERR(pg_ptr)) {
1239                 printk(KERN_WARNING "read_cache_page() returned error: %ld\n", PTR_ERR(pg_ptr));
1240                 return PTR_ERR(pg_ptr);
1241         }
1242
1243         offset = start;
1244         while(offset < orig_end) {
1245                 uint32_t datalen;
1246                 uint32_t cdatalen;
1247                 uint16_t comprtype = JFFS2_COMPR_NONE;
1248
1249                 ret = jffs2_reserve_space_gc(c, sizeof(ri) + JFFS2_MIN_DATA_LEN,
1250                                         &alloclen, JFFS2_SUMMARY_INODE_SIZE);
1251
1252                 if (ret) {
1253                         printk(KERN_WARNING "jffs2_reserve_space_gc of %zd bytes for garbage_collect_dnode failed: %d\n",
1254                                sizeof(ri)+ JFFS2_MIN_DATA_LEN, ret);
1255                         break;
1256                 }
1257                 cdatalen = min_t(uint32_t, alloclen - sizeof(ri), end - offset);
1258                 datalen = end - offset;
1259
1260                 writebuf = pg_ptr + (offset & (PAGE_CACHE_SIZE -1));
1261
1262                 comprtype = jffs2_compress(c, f, writebuf, &comprbuf, &datalen, &cdatalen);
1263
1264                 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
1265                 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
1266                 ri.totlen = cpu_to_je32(sizeof(ri) + cdatalen);
1267                 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
1268
1269                 ri.ino = cpu_to_je32(f->inocache->ino);
1270                 ri.version = cpu_to_je32(++f->highest_version);
1271                 ri.mode = cpu_to_jemode(JFFS2_F_I_MODE(f));
1272                 ri.uid = cpu_to_je16(JFFS2_F_I_UID(f));
1273                 ri.gid = cpu_to_je16(JFFS2_F_I_GID(f));
1274                 ri.isize = cpu_to_je32(JFFS2_F_I_SIZE(f));
1275                 ri.atime = cpu_to_je32(JFFS2_F_I_ATIME(f));
1276                 ri.ctime = cpu_to_je32(JFFS2_F_I_CTIME(f));
1277                 ri.mtime = cpu_to_je32(JFFS2_F_I_MTIME(f));
1278                 ri.offset = cpu_to_je32(offset);
1279                 ri.csize = cpu_to_je32(cdatalen);
1280                 ri.dsize = cpu_to_je32(datalen);
1281                 ri.compr = comprtype & 0xff;
1282                 ri.usercompr = (comprtype >> 8) & 0xff;
1283                 ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
1284                 ri.data_crc = cpu_to_je32(crc32(0, comprbuf, cdatalen));
1285
1286                 new_fn = jffs2_write_dnode(c, f, &ri, comprbuf, cdatalen, ALLOC_GC);
1287
1288                 jffs2_free_comprbuf(comprbuf, writebuf);
1289
1290                 if (IS_ERR(new_fn)) {
1291                         printk(KERN_WARNING "Error writing new dnode: %ld\n", PTR_ERR(new_fn));
1292                         ret = PTR_ERR(new_fn);
1293                         break;
1294                 }
1295                 ret = jffs2_add_full_dnode_to_inode(c, f, new_fn);
1296                 offset += datalen;
1297                 if (f->metadata) {
1298                         jffs2_mark_node_obsolete(c, f->metadata->raw);
1299                         jffs2_free_full_dnode(f->metadata);
1300                         f->metadata = NULL;
1301                 }
1302         }
1303
1304         jffs2_gc_release_page(c, pg_ptr, &pg);
1305         return ret;
1306 }