xref: /openbmc/linux/fs/jffs2/gc.c (revision 0cfc7da3)
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 1.155 2005/11/07 11:14:39 gleixner 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 again:
54 	if (!list_empty(&c->bad_used_list) && c->nr_free_blocks > c->resv_blocks_gcbad) {
55 		D1(printk(KERN_DEBUG "Picking block from bad_used_list to GC next\n"));
56 		nextlist = &c->bad_used_list;
57 	} else if (n < 50 && !list_empty(&c->erasable_list)) {
58 		/* Note that most of them will have gone directly to be erased.
59 		   So don't favour the erasable_list _too_ much. */
60 		D1(printk(KERN_DEBUG "Picking block from erasable_list to GC next\n"));
61 		nextlist = &c->erasable_list;
62 	} else if (n < 110 && !list_empty(&c->very_dirty_list)) {
63 		/* Most of the time, pick one off the very_dirty list */
64 		D1(printk(KERN_DEBUG "Picking block from very_dirty_list to GC next\n"));
65 		nextlist = &c->very_dirty_list;
66 	} else if (n < 126 && !list_empty(&c->dirty_list)) {
67 		D1(printk(KERN_DEBUG "Picking block from dirty_list to GC next\n"));
68 		nextlist = &c->dirty_list;
69 	} else if (!list_empty(&c->clean_list)) {
70 		D1(printk(KERN_DEBUG "Picking block from clean_list to GC next\n"));
71 		nextlist = &c->clean_list;
72 	} else if (!list_empty(&c->dirty_list)) {
73 		D1(printk(KERN_DEBUG "Picking block from dirty_list to GC next (clean_list was empty)\n"));
74 
75 		nextlist = &c->dirty_list;
76 	} else if (!list_empty(&c->very_dirty_list)) {
77 		D1(printk(KERN_DEBUG "Picking block from very_dirty_list to GC next (clean_list and dirty_list were empty)\n"));
78 		nextlist = &c->very_dirty_list;
79 	} else if (!list_empty(&c->erasable_list)) {
80 		D1(printk(KERN_DEBUG "Picking block from erasable_list to GC next (clean_list and {very_,}dirty_list were empty)\n"));
81 
82 		nextlist = &c->erasable_list;
83 	} else if (!list_empty(&c->erasable_pending_wbuf_list)) {
84 		/* There are blocks are wating for the wbuf sync */
85 		D1(printk(KERN_DEBUG "Synching wbuf in order to reuse erasable_pending_wbuf_list blocks\n"));
86 		spin_unlock(&c->erase_completion_lock);
87 		jffs2_flush_wbuf_pad(c);
88 		spin_lock(&c->erase_completion_lock);
89 		goto again;
90 	} else {
91 		/* Eep. All were empty */
92 		D1(printk(KERN_NOTICE "jffs2: No clean, dirty _or_ erasable blocks to GC from! Where are they all?\n"));
93 		return NULL;
94 	}
95 
96 	ret = list_entry(nextlist->next, struct jffs2_eraseblock, list);
97 	list_del(&ret->list);
98 	c->gcblock = ret;
99 	ret->gc_node = ret->first_node;
100 	if (!ret->gc_node) {
101 		printk(KERN_WARNING "Eep. ret->gc_node for block at 0x%08x is NULL\n", ret->offset);
102 		BUG();
103 	}
104 
105 	/* Have we accidentally picked a clean block with wasted space ? */
106 	if (ret->wasted_size) {
107 		D1(printk(KERN_DEBUG "Converting wasted_size %08x to dirty_size\n", ret->wasted_size));
108 		ret->dirty_size += ret->wasted_size;
109 		c->wasted_size -= ret->wasted_size;
110 		c->dirty_size += ret->wasted_size;
111 		ret->wasted_size = 0;
112 	}
113 
114 	return ret;
115 }
116 
117 /* jffs2_garbage_collect_pass
118  * Make a single attempt to progress GC. Move one node, and possibly
119  * start erasing one eraseblock.
120  */
121 int jffs2_garbage_collect_pass(struct jffs2_sb_info *c)
122 {
123 	struct jffs2_inode_info *f;
124 	struct jffs2_inode_cache *ic;
125 	struct jffs2_eraseblock *jeb;
126 	struct jffs2_raw_node_ref *raw;
127 	int ret = 0, inum, nlink;
128 	int xattr = 0;
129 
130 	if (down_interruptible(&c->alloc_sem))
131 		return -EINTR;
132 
133 	for (;;) {
134 		spin_lock(&c->erase_completion_lock);
135 		if (!c->unchecked_size)
136 			break;
137 
138 		/* We can't start doing GC yet. We haven't finished checking
139 		   the node CRCs etc. Do it now. */
140 
141 		/* checked_ino is protected by the alloc_sem */
142 		if (c->checked_ino > c->highest_ino && xattr) {
143 			printk(KERN_CRIT "Checked all inodes but still 0x%x bytes of unchecked space?\n",
144 			       c->unchecked_size);
145 			jffs2_dbg_dump_block_lists_nolock(c);
146 			spin_unlock(&c->erase_completion_lock);
147 			BUG();
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 			continue;
169 		}
170 		switch(ic->state) {
171 		case INO_STATE_CHECKEDABSENT:
172 		case INO_STATE_PRESENT:
173 			D1(printk(KERN_DEBUG "Skipping ino #%u already checked\n", ic->ino));
174 			spin_unlock(&c->inocache_lock);
175 			continue;
176 
177 		case INO_STATE_GC:
178 		case INO_STATE_CHECKING:
179 			printk(KERN_WARNING "Inode #%u is in state %d during CRC check phase!\n", ic->ino, ic->state);
180 			spin_unlock(&c->inocache_lock);
181 			BUG();
182 
183 		case INO_STATE_READING:
184 			/* We need to wait for it to finish, lest we move on
185 			   and trigger the BUG() above while we haven't yet
186 			   finished checking all its nodes */
187 			D1(printk(KERN_DEBUG "Waiting for ino #%u to finish reading\n", ic->ino));
188 			/* We need to come back again for the _same_ inode. We've
189 			 made no progress in this case, but that should be OK */
190 			c->checked_ino--;
191 
192 			up(&c->alloc_sem);
193 			sleep_on_spinunlock(&c->inocache_wq, &c->inocache_lock);
194 			return 0;
195 
196 		default:
197 			BUG();
198 
199 		case INO_STATE_UNCHECKED:
200 			;
201 		}
202 		ic->state = INO_STATE_CHECKING;
203 		spin_unlock(&c->inocache_lock);
204 
205 		D1(printk(KERN_DEBUG "jffs2_garbage_collect_pass() triggering inode scan of ino#%u\n", ic->ino));
206 
207 		ret = jffs2_do_crccheck_inode(c, ic);
208 		if (ret)
209 			printk(KERN_WARNING "Returned error for crccheck of ino #%u. Expect badness...\n", ic->ino);
210 
211 		jffs2_set_inocache_state(c, ic, INO_STATE_CHECKEDABSENT);
212 		up(&c->alloc_sem);
213 		return ret;
214 	}
215 
216 	/* First, work out which block we're garbage-collecting */
217 	jeb = c->gcblock;
218 
219 	if (!jeb)
220 		jeb = jffs2_find_gc_block(c);
221 
222 	if (!jeb) {
223 		D1 (printk(KERN_NOTICE "jffs2: Couldn't find erase block to garbage collect!\n"));
224 		spin_unlock(&c->erase_completion_lock);
225 		up(&c->alloc_sem);
226 		return -EIO;
227 	}
228 
229 	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));
230 	D1(if (c->nextblock)
231 	   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));
232 
233 	if (!jeb->used_size) {
234 		up(&c->alloc_sem);
235 		goto eraseit;
236 	}
237 
238 	raw = jeb->gc_node;
239 
240 	while(ref_obsolete(raw)) {
241 		D1(printk(KERN_DEBUG "Node at 0x%08x is obsolete... skipping\n", ref_offset(raw)));
242 		raw = raw->next_phys;
243 		if (unlikely(!raw)) {
244 			printk(KERN_WARNING "eep. End of raw list while still supposedly nodes to GC\n");
245 			printk(KERN_WARNING "erase block at 0x%08x. free_size 0x%08x, dirty_size 0x%08x, used_size 0x%08x\n",
246 			       jeb->offset, jeb->free_size, jeb->dirty_size, jeb->used_size);
247 			jeb->gc_node = raw;
248 			spin_unlock(&c->erase_completion_lock);
249 			up(&c->alloc_sem);
250 			BUG();
251 		}
252 	}
253 	jeb->gc_node = raw;
254 
255 	D1(printk(KERN_DEBUG "Going to garbage collect node at 0x%08x\n", ref_offset(raw)));
256 
257 	if (!raw->next_in_ino) {
258 		/* Inode-less node. Clean marker, snapshot or something like that */
259 		/* FIXME: If it's something that needs to be copied, including something
260 		   we don't grok that has JFFS2_NODETYPE_RWCOMPAT_COPY, we should do so */
261 		spin_unlock(&c->erase_completion_lock);
262 		jffs2_mark_node_obsolete(c, raw);
263 		up(&c->alloc_sem);
264 		goto eraseit_lock;
265 	}
266 
267 	ic = jffs2_raw_ref_to_ic(raw);
268 
269 #ifdef CONFIG_JFFS2_FS_XATTR
270 	/* When 'ic' refers xattr_datum/xattr_ref, this node is GCed as xattr.
271 	 * We can decide whether this node is inode or xattr by ic->class.     */
272 	if (ic->class == RAWNODE_CLASS_XATTR_DATUM
273 	    || ic->class == RAWNODE_CLASS_XATTR_REF) {
274 		BUG_ON(raw->next_in_ino != (void *)ic);
275 		spin_unlock(&c->erase_completion_lock);
276 
277 		if (ic->class == RAWNODE_CLASS_XATTR_DATUM) {
278 			ret = jffs2_garbage_collect_xattr_datum(c, (struct jffs2_xattr_datum *)ic);
279 		} else {
280 			ret = jffs2_garbage_collect_xattr_ref(c, (struct jffs2_xattr_ref *)ic);
281 		}
282 		goto release_sem;
283 	}
284 #endif
285 
286 	/* We need to hold the inocache. Either the erase_completion_lock or
287 	   the inocache_lock are sufficient; we trade down since the inocache_lock
288 	   causes less contention. */
289 	spin_lock(&c->inocache_lock);
290 
291 	spin_unlock(&c->erase_completion_lock);
292 
293 	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));
294 
295 	/* Three possibilities:
296 	   1. Inode is already in-core. We must iget it and do proper
297 	      updating to its fragtree, etc.
298 	   2. Inode is not in-core, node is REF_PRISTINE. We lock the
299 	      inocache to prevent a read_inode(), copy the node intact.
300 	   3. Inode is not in-core, node is not pristine. We must iget()
301 	      and take the slow path.
302 	*/
303 
304 	switch(ic->state) {
305 	case INO_STATE_CHECKEDABSENT:
306 		/* It's been checked, but it's not currently in-core.
307 		   We can just copy any pristine nodes, but have
308 		   to prevent anyone else from doing read_inode() while
309 		   we're at it, so we set the state accordingly */
310 		if (ref_flags(raw) == REF_PRISTINE)
311 			ic->state = INO_STATE_GC;
312 		else {
313 			D1(printk(KERN_DEBUG "Ino #%u is absent but node not REF_PRISTINE. Reading.\n",
314 				  ic->ino));
315 		}
316 		break;
317 
318 	case INO_STATE_PRESENT:
319 		/* It's in-core. GC must iget() it. */
320 		break;
321 
322 	case INO_STATE_UNCHECKED:
323 	case INO_STATE_CHECKING:
324 	case INO_STATE_GC:
325 		/* Should never happen. We should have finished checking
326 		   by the time we actually start doing any GC, and since
327 		   we're holding the alloc_sem, no other garbage collection
328 		   can happen.
329 		*/
330 		printk(KERN_CRIT "Inode #%u already in state %d in jffs2_garbage_collect_pass()!\n",
331 		       ic->ino, ic->state);
332 		up(&c->alloc_sem);
333 		spin_unlock(&c->inocache_lock);
334 		BUG();
335 
336 	case INO_STATE_READING:
337 		/* Someone's currently trying to read it. We must wait for
338 		   them to finish and then go through the full iget() route
339 		   to do the GC. However, sometimes read_inode() needs to get
340 		   the alloc_sem() (for marking nodes invalid) so we must
341 		   drop the alloc_sem before sleeping. */
342 
343 		up(&c->alloc_sem);
344 		D1(printk(KERN_DEBUG "jffs2_garbage_collect_pass() waiting for ino #%u in state %d\n",
345 			  ic->ino, ic->state));
346 		sleep_on_spinunlock(&c->inocache_wq, &c->inocache_lock);
347 		/* And because we dropped the alloc_sem we must start again from the
348 		   beginning. Ponder chance of livelock here -- we're returning success
349 		   without actually making any progress.
350 
351 		   Q: What are the chances that the inode is back in INO_STATE_READING
352 		   again by the time we next enter this function? And that this happens
353 		   enough times to cause a real delay?
354 
355 		   A: Small enough that I don't care :)
356 		*/
357 		return 0;
358 	}
359 
360 	/* OK. Now if the inode is in state INO_STATE_GC, we are going to copy the
361 	   node intact, and we don't have to muck about with the fragtree etc.
362 	   because we know it's not in-core. If it _was_ in-core, we go through
363 	   all the iget() crap anyway */
364 
365 	if (ic->state == INO_STATE_GC) {
366 		spin_unlock(&c->inocache_lock);
367 
368 		ret = jffs2_garbage_collect_pristine(c, ic, raw);
369 
370 		spin_lock(&c->inocache_lock);
371 		ic->state = INO_STATE_CHECKEDABSENT;
372 		wake_up(&c->inocache_wq);
373 
374 		if (ret != -EBADFD) {
375 			spin_unlock(&c->inocache_lock);
376 			goto release_sem;
377 		}
378 
379 		/* Fall through if it wanted us to, with inocache_lock held */
380 	}
381 
382 	/* Prevent the fairly unlikely race where the gcblock is
383 	   entirely obsoleted by the final close of a file which had
384 	   the only valid nodes in the block, followed by erasure,
385 	   followed by freeing of the ic because the erased block(s)
386 	   held _all_ the nodes of that inode.... never been seen but
387 	   it's vaguely possible. */
388 
389 	inum = ic->ino;
390 	nlink = ic->nlink;
391 	spin_unlock(&c->inocache_lock);
392 
393 	f = jffs2_gc_fetch_inode(c, inum, nlink);
394 	if (IS_ERR(f)) {
395 		ret = PTR_ERR(f);
396 		goto release_sem;
397 	}
398 	if (!f) {
399 		ret = 0;
400 		goto release_sem;
401 	}
402 
403 	ret = jffs2_garbage_collect_live(c, jeb, raw, f);
404 
405 	jffs2_gc_release_inode(c, f);
406 
407  release_sem:
408 	up(&c->alloc_sem);
409 
410  eraseit_lock:
411 	/* If we've finished this block, start it erasing */
412 	spin_lock(&c->erase_completion_lock);
413 
414  eraseit:
415 	if (c->gcblock && !c->gcblock->used_size) {
416 		D1(printk(KERN_DEBUG "Block at 0x%08x completely obsoleted by GC. Moving to erase_pending_list\n", c->gcblock->offset));
417 		/* We're GC'ing an empty block? */
418 		list_add_tail(&c->gcblock->list, &c->erase_pending_list);
419 		c->gcblock = NULL;
420 		c->nr_erasing_blocks++;
421 		jffs2_erase_pending_trigger(c);
422 	}
423 	spin_unlock(&c->erase_completion_lock);
424 
425 	return ret;
426 }
427 
428 static int jffs2_garbage_collect_live(struct jffs2_sb_info *c,  struct jffs2_eraseblock *jeb,
429 				      struct jffs2_raw_node_ref *raw, struct jffs2_inode_info *f)
430 {
431 	struct jffs2_node_frag *frag;
432 	struct jffs2_full_dnode *fn = NULL;
433 	struct jffs2_full_dirent *fd;
434 	uint32_t start = 0, end = 0, nrfrags = 0;
435 	int ret = 0;
436 
437 	down(&f->sem);
438 
439 	/* Now we have the lock for this inode. Check that it's still the one at the head
440 	   of the list. */
441 
442 	spin_lock(&c->erase_completion_lock);
443 
444 	if (c->gcblock != jeb) {
445 		spin_unlock(&c->erase_completion_lock);
446 		D1(printk(KERN_DEBUG "GC block is no longer gcblock. Restart\n"));
447 		goto upnout;
448 	}
449 	if (ref_obsolete(raw)) {
450 		spin_unlock(&c->erase_completion_lock);
451 		D1(printk(KERN_DEBUG "node to be GC'd was obsoleted in the meantime.\n"));
452 		/* They'll call again */
453 		goto upnout;
454 	}
455 	spin_unlock(&c->erase_completion_lock);
456 
457 	/* OK. Looks safe. And nobody can get us now because we have the semaphore. Move the block */
458 	if (f->metadata && f->metadata->raw == raw) {
459 		fn = f->metadata;
460 		ret = jffs2_garbage_collect_metadata(c, jeb, f, fn);
461 		goto upnout;
462 	}
463 
464 	/* FIXME. Read node and do lookup? */
465 	for (frag = frag_first(&f->fragtree); frag; frag = frag_next(frag)) {
466 		if (frag->node && frag->node->raw == raw) {
467 			fn = frag->node;
468 			end = frag->ofs + frag->size;
469 			if (!nrfrags++)
470 				start = frag->ofs;
471 			if (nrfrags == frag->node->frags)
472 				break; /* We've found them all */
473 		}
474 	}
475 	if (fn) {
476 		if (ref_flags(raw) == REF_PRISTINE) {
477 			ret = jffs2_garbage_collect_pristine(c, f->inocache, raw);
478 			if (!ret) {
479 				/* Urgh. Return it sensibly. */
480 				frag->node->raw = f->inocache->nodes;
481 			}
482 			if (ret != -EBADFD)
483 				goto upnout;
484 		}
485 		/* We found a datanode. Do the GC */
486 		if((start >> PAGE_CACHE_SHIFT) < ((end-1) >> PAGE_CACHE_SHIFT)) {
487 			/* It crosses a page boundary. Therefore, it must be a hole. */
488 			ret = jffs2_garbage_collect_hole(c, jeb, f, fn, start, end);
489 		} else {
490 			/* It could still be a hole. But we GC the page this way anyway */
491 			ret = jffs2_garbage_collect_dnode(c, jeb, f, fn, start, end);
492 		}
493 		goto upnout;
494 	}
495 
496 	/* Wasn't a dnode. Try dirent */
497 	for (fd = f->dents; fd; fd=fd->next) {
498 		if (fd->raw == raw)
499 			break;
500 	}
501 
502 	if (fd && fd->ino) {
503 		ret = jffs2_garbage_collect_dirent(c, jeb, f, fd);
504 	} else if (fd) {
505 		ret = jffs2_garbage_collect_deletion_dirent(c, jeb, f, fd);
506 	} else {
507 		printk(KERN_WARNING "Raw node at 0x%08x wasn't in node lists for ino #%u\n",
508 		       ref_offset(raw), f->inocache->ino);
509 		if (ref_obsolete(raw)) {
510 			printk(KERN_WARNING "But it's obsolete so we don't mind too much\n");
511 		} else {
512 			jffs2_dbg_dump_node(c, ref_offset(raw));
513 			BUG();
514 		}
515 	}
516  upnout:
517 	up(&f->sem);
518 
519 	return ret;
520 }
521 
522 static int jffs2_garbage_collect_pristine(struct jffs2_sb_info *c,
523 					  struct jffs2_inode_cache *ic,
524 					  struct jffs2_raw_node_ref *raw)
525 {
526 	union jffs2_node_union *node;
527 	struct jffs2_raw_node_ref *nraw;
528 	size_t retlen;
529 	int ret;
530 	uint32_t phys_ofs, alloclen;
531 	uint32_t crc, rawlen;
532 	int retried = 0;
533 
534 	D1(printk(KERN_DEBUG "Going to GC REF_PRISTINE node at 0x%08x\n", ref_offset(raw)));
535 
536 	rawlen = ref_totlen(c, c->gcblock, raw);
537 
538 	/* Ask for a small amount of space (or the totlen if smaller) because we
539 	   don't want to force wastage of the end of a block if splitting would
540 	   work. */
541 	ret = jffs2_reserve_space_gc(c, min_t(uint32_t, sizeof(struct jffs2_raw_inode) +
542 				JFFS2_MIN_DATA_LEN, rawlen), &phys_ofs, &alloclen, rawlen);
543 				/* this is not the exact summary size of it,
544 					it is only an upper estimation */
545 
546 	if (ret)
547 		return ret;
548 
549 	if (alloclen < rawlen) {
550 		/* Doesn't fit untouched. We'll go the old route and split it */
551 		return -EBADFD;
552 	}
553 
554 	node = kmalloc(rawlen, GFP_KERNEL);
555 	if (!node)
556                return -ENOMEM;
557 
558 	ret = jffs2_flash_read(c, ref_offset(raw), rawlen, &retlen, (char *)node);
559 	if (!ret && retlen != rawlen)
560 		ret = -EIO;
561 	if (ret)
562 		goto out_node;
563 
564 	crc = crc32(0, node, sizeof(struct jffs2_unknown_node)-4);
565 	if (je32_to_cpu(node->u.hdr_crc) != crc) {
566 		printk(KERN_WARNING "Header CRC failed on REF_PRISTINE node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
567 		       ref_offset(raw), je32_to_cpu(node->u.hdr_crc), crc);
568 		goto bail;
569 	}
570 
571 	switch(je16_to_cpu(node->u.nodetype)) {
572 	case JFFS2_NODETYPE_INODE:
573 		crc = crc32(0, node, sizeof(node->i)-8);
574 		if (je32_to_cpu(node->i.node_crc) != crc) {
575 			printk(KERN_WARNING "Node CRC failed on REF_PRISTINE data node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
576 			       ref_offset(raw), je32_to_cpu(node->i.node_crc), crc);
577 			goto bail;
578 		}
579 
580 		if (je32_to_cpu(node->i.dsize)) {
581 			crc = crc32(0, node->i.data, je32_to_cpu(node->i.csize));
582 			if (je32_to_cpu(node->i.data_crc) != crc) {
583 				printk(KERN_WARNING "Data CRC failed on REF_PRISTINE data node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
584 				       ref_offset(raw), je32_to_cpu(node->i.data_crc), crc);
585 				goto bail;
586 			}
587 		}
588 		break;
589 
590 	case JFFS2_NODETYPE_DIRENT:
591 		crc = crc32(0, node, sizeof(node->d)-8);
592 		if (je32_to_cpu(node->d.node_crc) != crc) {
593 			printk(KERN_WARNING "Node CRC failed on REF_PRISTINE dirent node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
594 			       ref_offset(raw), je32_to_cpu(node->d.node_crc), crc);
595 			goto bail;
596 		}
597 
598 		if (node->d.nsize) {
599 			crc = crc32(0, node->d.name, node->d.nsize);
600 			if (je32_to_cpu(node->d.name_crc) != crc) {
601 				printk(KERN_WARNING "Name CRC failed on REF_PRISTINE dirent ode at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
602 				       ref_offset(raw), je32_to_cpu(node->d.name_crc), crc);
603 				goto bail;
604 			}
605 		}
606 		break;
607 	default:
608 		printk(KERN_WARNING "Unknown node type for REF_PRISTINE node at 0x%08x: 0x%04x\n",
609 		       ref_offset(raw), je16_to_cpu(node->u.nodetype));
610 		goto bail;
611 	}
612 
613 	nraw = jffs2_alloc_raw_node_ref();
614 	if (!nraw) {
615 		ret = -ENOMEM;
616 		goto out_node;
617 	}
618 
619 	/* OK, all the CRCs are good; this node can just be copied as-is. */
620  retry:
621 	nraw->flash_offset = phys_ofs;
622 	nraw->__totlen = rawlen;
623 	nraw->next_phys = NULL;
624 
625 	ret = jffs2_flash_write(c, phys_ofs, rawlen, &retlen, (char *)node);
626 
627 	if (ret || (retlen != rawlen)) {
628 		printk(KERN_NOTICE "Write of %d bytes at 0x%08x failed. returned %d, retlen %zd\n",
629                        rawlen, phys_ofs, ret, retlen);
630 		if (retlen) {
631                         /* Doesn't belong to any inode */
632 			nraw->next_in_ino = NULL;
633 
634 			nraw->flash_offset |= REF_OBSOLETE;
635 			jffs2_add_physical_node_ref(c, nraw);
636 			jffs2_mark_node_obsolete(c, nraw);
637 		} else {
638 			printk(KERN_NOTICE "Not marking the space at 0x%08x as dirty because the flash driver returned retlen zero\n", nraw->flash_offset);
639                         jffs2_free_raw_node_ref(nraw);
640 		}
641 		if (!retried && (nraw = jffs2_alloc_raw_node_ref())) {
642 			/* Try to reallocate space and retry */
643 			uint32_t dummy;
644 			struct jffs2_eraseblock *jeb = &c->blocks[phys_ofs / c->sector_size];
645 
646 			retried = 1;
647 
648 			D1(printk(KERN_DEBUG "Retrying failed write of REF_PRISTINE node.\n"));
649 
650 			jffs2_dbg_acct_sanity_check(c,jeb);
651 			jffs2_dbg_acct_paranoia_check(c, jeb);
652 
653 			ret = jffs2_reserve_space_gc(c, rawlen, &phys_ofs, &dummy, rawlen);
654 						/* this is not the exact summary size of it,
655 							it is only an upper estimation */
656 
657 			if (!ret) {
658 				D1(printk(KERN_DEBUG "Allocated space at 0x%08x to retry failed write.\n", phys_ofs));
659 
660 				jffs2_dbg_acct_sanity_check(c,jeb);
661 				jffs2_dbg_acct_paranoia_check(c, jeb);
662 
663 				goto retry;
664 			}
665 			D1(printk(KERN_DEBUG "Failed to allocate space to retry failed write: %d!\n", ret));
666 			jffs2_free_raw_node_ref(nraw);
667 		}
668 
669 		jffs2_free_raw_node_ref(nraw);
670 		if (!ret)
671 			ret = -EIO;
672 		goto out_node;
673 	}
674 	nraw->flash_offset |= REF_PRISTINE;
675 	jffs2_add_physical_node_ref(c, nraw);
676 
677 	/* Link into per-inode list. This is safe because of the ic
678 	   state being INO_STATE_GC. Note that if we're doing this
679 	   for an inode which is in-core, the 'nraw' pointer is then
680 	   going to be fetched from ic->nodes by our caller. */
681 	spin_lock(&c->erase_completion_lock);
682         nraw->next_in_ino = ic->nodes;
683         ic->nodes = nraw;
684 	spin_unlock(&c->erase_completion_lock);
685 
686 	jffs2_mark_node_obsolete(c, raw);
687 	D1(printk(KERN_DEBUG "WHEEE! GC REF_PRISTINE node at 0x%08x succeeded\n", ref_offset(raw)));
688 
689  out_node:
690 	kfree(node);
691 	return ret;
692  bail:
693 	ret = -EBADFD;
694 	goto out_node;
695 }
696 
697 static int jffs2_garbage_collect_metadata(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
698 					struct jffs2_inode_info *f, struct jffs2_full_dnode *fn)
699 {
700 	struct jffs2_full_dnode *new_fn;
701 	struct jffs2_raw_inode ri;
702 	struct jffs2_node_frag *last_frag;
703 	union jffs2_device_node dev;
704 	char *mdata = NULL, mdatalen = 0;
705 	uint32_t alloclen, phys_ofs, ilen;
706 	int ret;
707 
708 	if (S_ISBLK(JFFS2_F_I_MODE(f)) ||
709 	    S_ISCHR(JFFS2_F_I_MODE(f)) ) {
710 		/* For these, we don't actually need to read the old node */
711 		mdatalen = jffs2_encode_dev(&dev, JFFS2_F_I_RDEV(f));
712 		mdata = (char *)&dev;
713 		D1(printk(KERN_DEBUG "jffs2_garbage_collect_metadata(): Writing %d bytes of kdev_t\n", mdatalen));
714 	} else if (S_ISLNK(JFFS2_F_I_MODE(f))) {
715 		mdatalen = fn->size;
716 		mdata = kmalloc(fn->size, GFP_KERNEL);
717 		if (!mdata) {
718 			printk(KERN_WARNING "kmalloc of mdata failed in jffs2_garbage_collect_metadata()\n");
719 			return -ENOMEM;
720 		}
721 		ret = jffs2_read_dnode(c, f, fn, mdata, 0, mdatalen);
722 		if (ret) {
723 			printk(KERN_WARNING "read of old metadata failed in jffs2_garbage_collect_metadata(): %d\n", ret);
724 			kfree(mdata);
725 			return ret;
726 		}
727 		D1(printk(KERN_DEBUG "jffs2_garbage_collect_metadata(): Writing %d bites of symlink target\n", mdatalen));
728 
729 	}
730 
731 	ret = jffs2_reserve_space_gc(c, sizeof(ri) + mdatalen, &phys_ofs, &alloclen,
732 				JFFS2_SUMMARY_INODE_SIZE);
733 	if (ret) {
734 		printk(KERN_WARNING "jffs2_reserve_space_gc of %zd bytes for garbage_collect_metadata failed: %d\n",
735 		       sizeof(ri)+ mdatalen, ret);
736 		goto out;
737 	}
738 
739 	last_frag = frag_last(&f->fragtree);
740 	if (last_frag)
741 		/* Fetch the inode length from the fragtree rather then
742 		 * from i_size since i_size may have not been updated yet */
743 		ilen = last_frag->ofs + last_frag->size;
744 	else
745 		ilen = JFFS2_F_I_SIZE(f);
746 
747 	memset(&ri, 0, sizeof(ri));
748 	ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
749 	ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
750 	ri.totlen = cpu_to_je32(sizeof(ri) + mdatalen);
751 	ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
752 
753 	ri.ino = cpu_to_je32(f->inocache->ino);
754 	ri.version = cpu_to_je32(++f->highest_version);
755 	ri.mode = cpu_to_jemode(JFFS2_F_I_MODE(f));
756 	ri.uid = cpu_to_je16(JFFS2_F_I_UID(f));
757 	ri.gid = cpu_to_je16(JFFS2_F_I_GID(f));
758 	ri.isize = cpu_to_je32(ilen);
759 	ri.atime = cpu_to_je32(JFFS2_F_I_ATIME(f));
760 	ri.ctime = cpu_to_je32(JFFS2_F_I_CTIME(f));
761 	ri.mtime = cpu_to_je32(JFFS2_F_I_MTIME(f));
762 	ri.offset = cpu_to_je32(0);
763 	ri.csize = cpu_to_je32(mdatalen);
764 	ri.dsize = cpu_to_je32(mdatalen);
765 	ri.compr = JFFS2_COMPR_NONE;
766 	ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
767 	ri.data_crc = cpu_to_je32(crc32(0, mdata, mdatalen));
768 
769 	new_fn = jffs2_write_dnode(c, f, &ri, mdata, mdatalen, phys_ofs, ALLOC_GC);
770 
771 	if (IS_ERR(new_fn)) {
772 		printk(KERN_WARNING "Error writing new dnode: %ld\n", PTR_ERR(new_fn));
773 		ret = PTR_ERR(new_fn);
774 		goto out;
775 	}
776 	jffs2_mark_node_obsolete(c, fn->raw);
777 	jffs2_free_full_dnode(fn);
778 	f->metadata = new_fn;
779  out:
780 	if (S_ISLNK(JFFS2_F_I_MODE(f)))
781 		kfree(mdata);
782 	return ret;
783 }
784 
785 static int jffs2_garbage_collect_dirent(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
786 					struct jffs2_inode_info *f, struct jffs2_full_dirent *fd)
787 {
788 	struct jffs2_full_dirent *new_fd;
789 	struct jffs2_raw_dirent rd;
790 	uint32_t alloclen, phys_ofs;
791 	int ret;
792 
793 	rd.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
794 	rd.nodetype = cpu_to_je16(JFFS2_NODETYPE_DIRENT);
795 	rd.nsize = strlen(fd->name);
796 	rd.totlen = cpu_to_je32(sizeof(rd) + rd.nsize);
797 	rd.hdr_crc = cpu_to_je32(crc32(0, &rd, sizeof(struct jffs2_unknown_node)-4));
798 
799 	rd.pino = cpu_to_je32(f->inocache->ino);
800 	rd.version = cpu_to_je32(++f->highest_version);
801 	rd.ino = cpu_to_je32(fd->ino);
802 	/* If the times on this inode were set by explicit utime() they can be different,
803 	   so refrain from splatting them. */
804 	if (JFFS2_F_I_MTIME(f) == JFFS2_F_I_CTIME(f))
805 		rd.mctime = cpu_to_je32(JFFS2_F_I_MTIME(f));
806 	else
807 		rd.mctime = cpu_to_je32(0);
808 	rd.type = fd->type;
809 	rd.node_crc = cpu_to_je32(crc32(0, &rd, sizeof(rd)-8));
810 	rd.name_crc = cpu_to_je32(crc32(0, fd->name, rd.nsize));
811 
812 	ret = jffs2_reserve_space_gc(c, sizeof(rd)+rd.nsize, &phys_ofs, &alloclen,
813 				JFFS2_SUMMARY_DIRENT_SIZE(rd.nsize));
814 	if (ret) {
815 		printk(KERN_WARNING "jffs2_reserve_space_gc of %zd bytes for garbage_collect_dirent failed: %d\n",
816 		       sizeof(rd)+rd.nsize, ret);
817 		return ret;
818 	}
819 	new_fd = jffs2_write_dirent(c, f, &rd, fd->name, rd.nsize, phys_ofs, ALLOC_GC);
820 
821 	if (IS_ERR(new_fd)) {
822 		printk(KERN_WARNING "jffs2_write_dirent in garbage_collect_dirent failed: %ld\n", PTR_ERR(new_fd));
823 		return PTR_ERR(new_fd);
824 	}
825 	jffs2_add_fd_to_list(c, new_fd, &f->dents);
826 	return 0;
827 }
828 
829 static int jffs2_garbage_collect_deletion_dirent(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
830 					struct jffs2_inode_info *f, struct jffs2_full_dirent *fd)
831 {
832 	struct jffs2_full_dirent **fdp = &f->dents;
833 	int found = 0;
834 
835 	/* On a medium where we can't actually mark nodes obsolete
836 	   pernamently, such as NAND flash, we need to work out
837 	   whether this deletion dirent is still needed to actively
838 	   delete a 'real' dirent with the same name that's still
839 	   somewhere else on the flash. */
840 	if (!jffs2_can_mark_obsolete(c)) {
841 		struct jffs2_raw_dirent *rd;
842 		struct jffs2_raw_node_ref *raw;
843 		int ret;
844 		size_t retlen;
845 		int name_len = strlen(fd->name);
846 		uint32_t name_crc = crc32(0, fd->name, name_len);
847 		uint32_t rawlen = ref_totlen(c, jeb, fd->raw);
848 
849 		rd = kmalloc(rawlen, GFP_KERNEL);
850 		if (!rd)
851 			return -ENOMEM;
852 
853 		/* Prevent the erase code from nicking the obsolete node refs while
854 		   we're looking at them. I really don't like this extra lock but
855 		   can't see any alternative. Suggestions on a postcard to... */
856 		down(&c->erase_free_sem);
857 
858 		for (raw = f->inocache->nodes; raw != (void *)f->inocache; raw = raw->next_in_ino) {
859 
860 			/* We only care about obsolete ones */
861 			if (!(ref_obsolete(raw)))
862 				continue;
863 
864 			/* Any dirent with the same name is going to have the same length... */
865 			if (ref_totlen(c, NULL, raw) != rawlen)
866 				continue;
867 
868 			/* Doesn't matter if there's one in the same erase block. We're going to
869 			   delete it too at the same time. */
870 			if (SECTOR_ADDR(raw->flash_offset) == SECTOR_ADDR(fd->raw->flash_offset))
871 				continue;
872 
873 			D1(printk(KERN_DEBUG "Check potential deletion dirent at %08x\n", ref_offset(raw)));
874 
875 			/* This is an obsolete node belonging to the same directory, and it's of the right
876 			   length. We need to take a closer look...*/
877 			ret = jffs2_flash_read(c, ref_offset(raw), rawlen, &retlen, (char *)rd);
878 			if (ret) {
879 				printk(KERN_WARNING "jffs2_g_c_deletion_dirent(): Read error (%d) reading obsolete node at %08x\n", ret, ref_offset(raw));
880 				/* If we can't read it, we don't need to continue to obsolete it. Continue */
881 				continue;
882 			}
883 			if (retlen != rawlen) {
884 				printk(KERN_WARNING "jffs2_g_c_deletion_dirent(): Short read (%zd not %u) reading header from obsolete node at %08x\n",
885 				       retlen, rawlen, ref_offset(raw));
886 				continue;
887 			}
888 
889 			if (je16_to_cpu(rd->nodetype) != JFFS2_NODETYPE_DIRENT)
890 				continue;
891 
892 			/* If the name CRC doesn't match, skip */
893 			if (je32_to_cpu(rd->name_crc) != name_crc)
894 				continue;
895 
896 			/* If the name length doesn't match, or it's another deletion dirent, skip */
897 			if (rd->nsize != name_len || !je32_to_cpu(rd->ino))
898 				continue;
899 
900 			/* OK, check the actual name now */
901 			if (memcmp(rd->name, fd->name, name_len))
902 				continue;
903 
904 			/* OK. The name really does match. There really is still an older node on
905 			   the flash which our deletion dirent obsoletes. So we have to write out
906 			   a new deletion dirent to replace it */
907 			up(&c->erase_free_sem);
908 
909 			D1(printk(KERN_DEBUG "Deletion dirent at %08x still obsoletes real dirent \"%s\" at %08x for ino #%u\n",
910 				  ref_offset(fd->raw), fd->name, ref_offset(raw), je32_to_cpu(rd->ino)));
911 			kfree(rd);
912 
913 			return jffs2_garbage_collect_dirent(c, jeb, f, fd);
914 		}
915 
916 		up(&c->erase_free_sem);
917 		kfree(rd);
918 	}
919 
920 	/* FIXME: If we're deleting a dirent which contains the current mtime and ctime,
921 	   we should update the metadata node with those times accordingly */
922 
923 	/* No need for it any more. Just mark it obsolete and remove it from the list */
924 	while (*fdp) {
925 		if ((*fdp) == fd) {
926 			found = 1;
927 			*fdp = fd->next;
928 			break;
929 		}
930 		fdp = &(*fdp)->next;
931 	}
932 	if (!found) {
933 		printk(KERN_WARNING "Deletion dirent \"%s\" not found in list for ino #%u\n", fd->name, f->inocache->ino);
934 	}
935 	jffs2_mark_node_obsolete(c, fd->raw);
936 	jffs2_free_full_dirent(fd);
937 	return 0;
938 }
939 
940 static int jffs2_garbage_collect_hole(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
941 				      struct jffs2_inode_info *f, struct jffs2_full_dnode *fn,
942 				      uint32_t start, uint32_t end)
943 {
944 	struct jffs2_raw_inode ri;
945 	struct jffs2_node_frag *frag;
946 	struct jffs2_full_dnode *new_fn;
947 	uint32_t alloclen, phys_ofs, ilen;
948 	int ret;
949 
950 	D1(printk(KERN_DEBUG "Writing replacement hole node for ino #%u from offset 0x%x to 0x%x\n",
951 		  f->inocache->ino, start, end));
952 
953 	memset(&ri, 0, sizeof(ri));
954 
955 	if(fn->frags > 1) {
956 		size_t readlen;
957 		uint32_t crc;
958 		/* It's partially obsoleted by a later write. So we have to
959 		   write it out again with the _same_ version as before */
960 		ret = jffs2_flash_read(c, ref_offset(fn->raw), sizeof(ri), &readlen, (char *)&ri);
961 		if (readlen != sizeof(ri) || ret) {
962 			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);
963 			goto fill;
964 		}
965 		if (je16_to_cpu(ri.nodetype) != JFFS2_NODETYPE_INODE) {
966 			printk(KERN_WARNING "jffs2_garbage_collect_hole: Node at 0x%08x had node type 0x%04x instead of JFFS2_NODETYPE_INODE(0x%04x)\n",
967 			       ref_offset(fn->raw),
968 			       je16_to_cpu(ri.nodetype), JFFS2_NODETYPE_INODE);
969 			return -EIO;
970 		}
971 		if (je32_to_cpu(ri.totlen) != sizeof(ri)) {
972 			printk(KERN_WARNING "jffs2_garbage_collect_hole: Node at 0x%08x had totlen 0x%x instead of expected 0x%zx\n",
973 			       ref_offset(fn->raw),
974 			       je32_to_cpu(ri.totlen), sizeof(ri));
975 			return -EIO;
976 		}
977 		crc = crc32(0, &ri, sizeof(ri)-8);
978 		if (crc != je32_to_cpu(ri.node_crc)) {
979 			printk(KERN_WARNING "jffs2_garbage_collect_hole: Node at 0x%08x had CRC 0x%08x which doesn't match calculated CRC 0x%08x\n",
980 			       ref_offset(fn->raw),
981 			       je32_to_cpu(ri.node_crc), crc);
982 			/* FIXME: We could possibly deal with this by writing new holes for each frag */
983 			printk(KERN_WARNING "Data in the range 0x%08x to 0x%08x of inode #%u will be lost\n",
984 			       start, end, f->inocache->ino);
985 			goto fill;
986 		}
987 		if (ri.compr != JFFS2_COMPR_ZERO) {
988 			printk(KERN_WARNING "jffs2_garbage_collect_hole: Node 0x%08x wasn't a hole node!\n", ref_offset(fn->raw));
989 			printk(KERN_WARNING "Data in the range 0x%08x to 0x%08x of inode #%u will be lost\n",
990 			       start, end, f->inocache->ino);
991 			goto fill;
992 		}
993 	} else {
994 	fill:
995 		ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
996 		ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
997 		ri.totlen = cpu_to_je32(sizeof(ri));
998 		ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
999 
1000 		ri.ino = cpu_to_je32(f->inocache->ino);
1001 		ri.version = cpu_to_je32(++f->highest_version);
1002 		ri.offset = cpu_to_je32(start);
1003 		ri.dsize = cpu_to_je32(end - start);
1004 		ri.csize = cpu_to_je32(0);
1005 		ri.compr = JFFS2_COMPR_ZERO;
1006 	}
1007 
1008 	frag = frag_last(&f->fragtree);
1009 	if (frag)
1010 		/* Fetch the inode length from the fragtree rather then
1011 		 * from i_size since i_size may have not been updated yet */
1012 		ilen = frag->ofs + frag->size;
1013 	else
1014 		ilen = JFFS2_F_I_SIZE(f);
1015 
1016 	ri.mode = cpu_to_jemode(JFFS2_F_I_MODE(f));
1017 	ri.uid = cpu_to_je16(JFFS2_F_I_UID(f));
1018 	ri.gid = cpu_to_je16(JFFS2_F_I_GID(f));
1019 	ri.isize = cpu_to_je32(ilen);
1020 	ri.atime = cpu_to_je32(JFFS2_F_I_ATIME(f));
1021 	ri.ctime = cpu_to_je32(JFFS2_F_I_CTIME(f));
1022 	ri.mtime = cpu_to_je32(JFFS2_F_I_MTIME(f));
1023 	ri.data_crc = cpu_to_je32(0);
1024 	ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
1025 
1026 	ret = jffs2_reserve_space_gc(c, sizeof(ri), &phys_ofs, &alloclen,
1027 				JFFS2_SUMMARY_INODE_SIZE);
1028 	if (ret) {
1029 		printk(KERN_WARNING "jffs2_reserve_space_gc of %zd bytes for garbage_collect_hole failed: %d\n",
1030 		       sizeof(ri), ret);
1031 		return ret;
1032 	}
1033 	new_fn = jffs2_write_dnode(c, f, &ri, NULL, 0, phys_ofs, ALLOC_GC);
1034 
1035 	if (IS_ERR(new_fn)) {
1036 		printk(KERN_WARNING "Error writing new hole node: %ld\n", PTR_ERR(new_fn));
1037 		return PTR_ERR(new_fn);
1038 	}
1039 	if (je32_to_cpu(ri.version) == f->highest_version) {
1040 		jffs2_add_full_dnode_to_inode(c, f, new_fn);
1041 		if (f->metadata) {
1042 			jffs2_mark_node_obsolete(c, f->metadata->raw);
1043 			jffs2_free_full_dnode(f->metadata);
1044 			f->metadata = NULL;
1045 		}
1046 		return 0;
1047 	}
1048 
1049 	/*
1050 	 * We should only get here in the case where the node we are
1051 	 * replacing had more than one frag, so we kept the same version
1052 	 * number as before. (Except in case of error -- see 'goto fill;'
1053 	 * above.)
1054 	 */
1055 	D1(if(unlikely(fn->frags <= 1)) {
1056 		printk(KERN_WARNING "jffs2_garbage_collect_hole: Replacing fn with %d frag(s) but new ver %d != highest_version %d of ino #%d\n",
1057 		       fn->frags, je32_to_cpu(ri.version), f->highest_version,
1058 		       je32_to_cpu(ri.ino));
1059 	});
1060 
1061 	/* This is a partially-overlapped hole node. Mark it REF_NORMAL not REF_PRISTINE */
1062 	mark_ref_normal(new_fn->raw);
1063 
1064 	for (frag = jffs2_lookup_node_frag(&f->fragtree, fn->ofs);
1065 	     frag; frag = frag_next(frag)) {
1066 		if (frag->ofs > fn->size + fn->ofs)
1067 			break;
1068 		if (frag->node == fn) {
1069 			frag->node = new_fn;
1070 			new_fn->frags++;
1071 			fn->frags--;
1072 		}
1073 	}
1074 	if (fn->frags) {
1075 		printk(KERN_WARNING "jffs2_garbage_collect_hole: Old node still has frags!\n");
1076 		BUG();
1077 	}
1078 	if (!new_fn->frags) {
1079 		printk(KERN_WARNING "jffs2_garbage_collect_hole: New node has no frags!\n");
1080 		BUG();
1081 	}
1082 
1083 	jffs2_mark_node_obsolete(c, fn->raw);
1084 	jffs2_free_full_dnode(fn);
1085 
1086 	return 0;
1087 }
1088 
1089 static int jffs2_garbage_collect_dnode(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
1090 				       struct jffs2_inode_info *f, struct jffs2_full_dnode *fn,
1091 				       uint32_t start, uint32_t end)
1092 {
1093 	struct jffs2_full_dnode *new_fn;
1094 	struct jffs2_raw_inode ri;
1095 	uint32_t alloclen, phys_ofs, offset, orig_end, orig_start;
1096 	int ret = 0;
1097 	unsigned char *comprbuf = NULL, *writebuf;
1098 	unsigned long pg;
1099 	unsigned char *pg_ptr;
1100 
1101 	memset(&ri, 0, sizeof(ri));
1102 
1103 	D1(printk(KERN_DEBUG "Writing replacement dnode for ino #%u from offset 0x%x to 0x%x\n",
1104 		  f->inocache->ino, start, end));
1105 
1106 	orig_end = end;
1107 	orig_start = start;
1108 
1109 	if (c->nr_free_blocks + c->nr_erasing_blocks > c->resv_blocks_gcmerge) {
1110 		/* Attempt to do some merging. But only expand to cover logically
1111 		   adjacent frags if the block containing them is already considered
1112 		   to be dirty. Otherwise we end up with GC just going round in
1113 		   circles dirtying the nodes it already wrote out, especially
1114 		   on NAND where we have small eraseblocks and hence a much higher
1115 		   chance of nodes having to be split to cross boundaries. */
1116 
1117 		struct jffs2_node_frag *frag;
1118 		uint32_t min, max;
1119 
1120 		min = start & ~(PAGE_CACHE_SIZE-1);
1121 		max = min + PAGE_CACHE_SIZE;
1122 
1123 		frag = jffs2_lookup_node_frag(&f->fragtree, start);
1124 
1125 		/* BUG_ON(!frag) but that'll happen anyway... */
1126 
1127 		BUG_ON(frag->ofs != start);
1128 
1129 		/* First grow down... */
1130 		while((frag = frag_prev(frag)) && frag->ofs >= min) {
1131 
1132 			/* If the previous frag doesn't even reach the beginning, there's
1133 			   excessive fragmentation. Just merge. */
1134 			if (frag->ofs > min) {
1135 				D1(printk(KERN_DEBUG "Expanding down to cover partial frag (0x%x-0x%x)\n",
1136 					  frag->ofs, frag->ofs+frag->size));
1137 				start = frag->ofs;
1138 				continue;
1139 			}
1140 			/* OK. This frag holds the first byte of the page. */
1141 			if (!frag->node || !frag->node->raw) {
1142 				D1(printk(KERN_DEBUG "First frag in page is hole (0x%x-0x%x). Not expanding down.\n",
1143 					  frag->ofs, frag->ofs+frag->size));
1144 				break;
1145 			} else {
1146 
1147 				/* OK, it's a frag which extends to the beginning of the page. Does it live
1148 				   in a block which is still considered clean? If so, don't obsolete it.
1149 				   If not, cover it anyway. */
1150 
1151 				struct jffs2_raw_node_ref *raw = frag->node->raw;
1152 				struct jffs2_eraseblock *jeb;
1153 
1154 				jeb = &c->blocks[raw->flash_offset / c->sector_size];
1155 
1156 				if (jeb == c->gcblock) {
1157 					D1(printk(KERN_DEBUG "Expanding down to cover frag (0x%x-0x%x) in gcblock at %08x\n",
1158 						  frag->ofs, frag->ofs+frag->size, ref_offset(raw)));
1159 					start = frag->ofs;
1160 					break;
1161 				}
1162 				if (!ISDIRTY(jeb->dirty_size + jeb->wasted_size)) {
1163 					D1(printk(KERN_DEBUG "Not expanding down to cover frag (0x%x-0x%x) in clean block %08x\n",
1164 						  frag->ofs, frag->ofs+frag->size, jeb->offset));
1165 					break;
1166 				}
1167 
1168 				D1(printk(KERN_DEBUG "Expanding down to cover frag (0x%x-0x%x) in dirty block %08x\n",
1169 						  frag->ofs, frag->ofs+frag->size, jeb->offset));
1170 				start = frag->ofs;
1171 				break;
1172 			}
1173 		}
1174 
1175 		/* ... then up */
1176 
1177 		/* Find last frag which is actually part of the node we're to GC. */
1178 		frag = jffs2_lookup_node_frag(&f->fragtree, end-1);
1179 
1180 		while((frag = frag_next(frag)) && frag->ofs+frag->size <= max) {
1181 
1182 			/* If the previous frag doesn't even reach the beginning, there's lots
1183 			   of fragmentation. Just merge. */
1184 			if (frag->ofs+frag->size < max) {
1185 				D1(printk(KERN_DEBUG "Expanding up to cover partial frag (0x%x-0x%x)\n",
1186 					  frag->ofs, frag->ofs+frag->size));
1187 				end = frag->ofs + frag->size;
1188 				continue;
1189 			}
1190 
1191 			if (!frag->node || !frag->node->raw) {
1192 				D1(printk(KERN_DEBUG "Last frag in page is hole (0x%x-0x%x). Not expanding up.\n",
1193 					  frag->ofs, frag->ofs+frag->size));
1194 				break;
1195 			} else {
1196 
1197 				/* OK, it's a frag which extends to the beginning of the page. Does it live
1198 				   in a block which is still considered clean? If so, don't obsolete it.
1199 				   If not, cover it anyway. */
1200 
1201 				struct jffs2_raw_node_ref *raw = frag->node->raw;
1202 				struct jffs2_eraseblock *jeb;
1203 
1204 				jeb = &c->blocks[raw->flash_offset / c->sector_size];
1205 
1206 				if (jeb == c->gcblock) {
1207 					D1(printk(KERN_DEBUG "Expanding up to cover frag (0x%x-0x%x) in gcblock at %08x\n",
1208 						  frag->ofs, frag->ofs+frag->size, ref_offset(raw)));
1209 					end = frag->ofs + frag->size;
1210 					break;
1211 				}
1212 				if (!ISDIRTY(jeb->dirty_size + jeb->wasted_size)) {
1213 					D1(printk(KERN_DEBUG "Not expanding up to cover frag (0x%x-0x%x) in clean block %08x\n",
1214 						  frag->ofs, frag->ofs+frag->size, jeb->offset));
1215 					break;
1216 				}
1217 
1218 				D1(printk(KERN_DEBUG "Expanding up to cover frag (0x%x-0x%x) in dirty block %08x\n",
1219 						  frag->ofs, frag->ofs+frag->size, jeb->offset));
1220 				end = frag->ofs + frag->size;
1221 				break;
1222 			}
1223 		}
1224 		D1(printk(KERN_DEBUG "Expanded dnode to write from (0x%x-0x%x) to (0x%x-0x%x)\n",
1225 			  orig_start, orig_end, start, end));
1226 
1227 		D1(BUG_ON(end > frag_last(&f->fragtree)->ofs + frag_last(&f->fragtree)->size));
1228 		BUG_ON(end < orig_end);
1229 		BUG_ON(start > orig_start);
1230 	}
1231 
1232 	/* First, use readpage() to read the appropriate page into the page cache */
1233 	/* Q: What happens if we actually try to GC the _same_ page for which commit_write()
1234 	 *    triggered garbage collection in the first place?
1235 	 * A: I _think_ it's OK. read_cache_page shouldn't deadlock, we'll write out the
1236 	 *    page OK. We'll actually write it out again in commit_write, which is a little
1237 	 *    suboptimal, but at least we're correct.
1238 	 */
1239 	pg_ptr = jffs2_gc_fetch_page(c, f, start, &pg);
1240 
1241 	if (IS_ERR(pg_ptr)) {
1242 		printk(KERN_WARNING "read_cache_page() returned error: %ld\n", PTR_ERR(pg_ptr));
1243 		return PTR_ERR(pg_ptr);
1244 	}
1245 
1246 	offset = start;
1247 	while(offset < orig_end) {
1248 		uint32_t datalen;
1249 		uint32_t cdatalen;
1250 		uint16_t comprtype = JFFS2_COMPR_NONE;
1251 
1252 		ret = jffs2_reserve_space_gc(c, sizeof(ri) + JFFS2_MIN_DATA_LEN, &phys_ofs,
1253 					&alloclen, JFFS2_SUMMARY_INODE_SIZE);
1254 
1255 		if (ret) {
1256 			printk(KERN_WARNING "jffs2_reserve_space_gc of %zd bytes for garbage_collect_dnode failed: %d\n",
1257 			       sizeof(ri)+ JFFS2_MIN_DATA_LEN, ret);
1258 			break;
1259 		}
1260 		cdatalen = min_t(uint32_t, alloclen - sizeof(ri), end - offset);
1261 		datalen = end - offset;
1262 
1263 		writebuf = pg_ptr + (offset & (PAGE_CACHE_SIZE -1));
1264 
1265 		comprtype = jffs2_compress(c, f, writebuf, &comprbuf, &datalen, &cdatalen);
1266 
1267 		ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
1268 		ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
1269 		ri.totlen = cpu_to_je32(sizeof(ri) + cdatalen);
1270 		ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
1271 
1272 		ri.ino = cpu_to_je32(f->inocache->ino);
1273 		ri.version = cpu_to_je32(++f->highest_version);
1274 		ri.mode = cpu_to_jemode(JFFS2_F_I_MODE(f));
1275 		ri.uid = cpu_to_je16(JFFS2_F_I_UID(f));
1276 		ri.gid = cpu_to_je16(JFFS2_F_I_GID(f));
1277 		ri.isize = cpu_to_je32(JFFS2_F_I_SIZE(f));
1278 		ri.atime = cpu_to_je32(JFFS2_F_I_ATIME(f));
1279 		ri.ctime = cpu_to_je32(JFFS2_F_I_CTIME(f));
1280 		ri.mtime = cpu_to_je32(JFFS2_F_I_MTIME(f));
1281 		ri.offset = cpu_to_je32(offset);
1282 		ri.csize = cpu_to_je32(cdatalen);
1283 		ri.dsize = cpu_to_je32(datalen);
1284 		ri.compr = comprtype & 0xff;
1285 		ri.usercompr = (comprtype >> 8) & 0xff;
1286 		ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
1287 		ri.data_crc = cpu_to_je32(crc32(0, comprbuf, cdatalen));
1288 
1289 		new_fn = jffs2_write_dnode(c, f, &ri, comprbuf, cdatalen, phys_ofs, ALLOC_GC);
1290 
1291 		jffs2_free_comprbuf(comprbuf, writebuf);
1292 
1293 		if (IS_ERR(new_fn)) {
1294 			printk(KERN_WARNING "Error writing new dnode: %ld\n", PTR_ERR(new_fn));
1295 			ret = PTR_ERR(new_fn);
1296 			break;
1297 		}
1298 		ret = jffs2_add_full_dnode_to_inode(c, f, new_fn);
1299 		offset += datalen;
1300 		if (f->metadata) {
1301 			jffs2_mark_node_obsolete(c, f->metadata->raw);
1302 			jffs2_free_full_dnode(f->metadata);
1303 			f->metadata = NULL;
1304 		}
1305 	}
1306 
1307 	jffs2_gc_release_page(c, pg_ptr, &pg);
1308 	return ret;
1309 }
1310