/*
 * JFFS2 -- Journalling Flash File System, Version 2.
 *
 * Copyright (C) 2001-2003 Red Hat, Inc.
 *
 * Created by David Woodhouse <dwmw2@redhat.com>
 *
 * For licensing information, see the file 'LICENCE' in this directory.
 *
 * $Id: nodelist.c,v 1.80 2003/10/04 08:33:06 dwmw2 Exp $
 *
 */

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/fs.h>
#include <linux/mtd/mtd.h>
#include <linux/rbtree.h>
#include <linux/crc32.h>
#include <linux/slab.h>
#include <linux/pagemap.h>
#include "nodelist.h"

void jffs2_add_fd_to_list(struct jffs2_sb_info *c, struct jffs2_full_dirent *new, struct jffs2_full_dirent **list)
{
	struct jffs2_full_dirent **prev = list;
	D1(printk(KERN_DEBUG "jffs2_add_fd_to_list( %p, %p (->%p))\n", new, list, *list));

	while ((*prev) && (*prev)->nhash <= new->nhash) {
		if ((*prev)->nhash == new->nhash && !strcmp((*prev)->name, new->name)) {
			/* Duplicate. Free one */
			if (new->version < (*prev)->version) {
				D1(printk(KERN_DEBUG "Eep! Marking new dirent node obsolete\n"));
				D1(printk(KERN_DEBUG "New dirent is \"%s\"->ino #%u. Old is \"%s\"->ino #%u\n", new->name, new->ino, (*prev)->name, (*prev)->ino));
				jffs2_mark_node_obsolete(c, new->raw);
				jffs2_free_full_dirent(new);
			} else {
				D1(printk(KERN_DEBUG "Marking old dirent node (ino #%u) obsolete\n", (*prev)->ino));
				new->next = (*prev)->next;
				jffs2_mark_node_obsolete(c, ((*prev)->raw));
				jffs2_free_full_dirent(*prev);
				*prev = new;
			}
			goto out;
		}
		prev = &((*prev)->next);
	}
	new->next = *prev;
	*prev = new;

 out:
	D2(while(*list) {
		printk(KERN_DEBUG "Dirent \"%s\" (hash 0x%08x, ino #%u\n", (*list)->name, (*list)->nhash, (*list)->ino);
		list = &(*list)->next;
	});
}

/* Put a new tmp_dnode_info into the list, keeping the list in 
   order of increasing version
*/
void jffs2_add_tn_to_list(struct jffs2_tmp_dnode_info *tn, struct jffs2_tmp_dnode_info **list)
{
	struct jffs2_tmp_dnode_info **prev = list;
	
	while ((*prev) && (*prev)->version < tn->version) {
		prev = &((*prev)->next);
	}
	tn->next = (*prev);
        *prev = tn;
}

static void jffs2_free_tmp_dnode_info_list(struct jffs2_tmp_dnode_info *tn)
{
	struct jffs2_tmp_dnode_info *next;

	while (tn) {
		next = tn;
		tn = tn->next;
		jffs2_free_full_dnode(next->fn);
		jffs2_free_tmp_dnode_info(next);
	}
}

static void jffs2_free_full_dirent_list(struct jffs2_full_dirent *fd)
{
	struct jffs2_full_dirent *next;

	while (fd) {
		next = fd->next;
		jffs2_free_full_dirent(fd);
		fd = next;
	}
}


/* Get tmp_dnode_info and full_dirent for all non-obsolete nodes associated
   with this ino, returning the former in order of version */

int jffs2_get_inode_nodes(struct jffs2_sb_info *c, ino_t ino, struct jffs2_inode_info *f,
			  struct jffs2_tmp_dnode_info **tnp, struct jffs2_full_dirent **fdp,
			  uint32_t *highest_version, uint32_t *latest_mctime,
			  uint32_t *mctime_ver)
{
	struct jffs2_raw_node_ref *ref = f->inocache->nodes;
	struct jffs2_tmp_dnode_info *tn, *ret_tn = NULL;
	struct jffs2_full_dirent *fd, *ret_fd = NULL;

	union jffs2_node_union node;
	size_t retlen;
	int err;

	*mctime_ver = 0;

	D1(printk(KERN_DEBUG "jffs2_get_inode_nodes(): ino #%lu\n", ino));
	if (!f->inocache->nodes) {
		printk(KERN_WARNING "Eep. no nodes for ino #%lu\n", (unsigned long)ino);
	}

	spin_lock(&c->erase_completion_lock);

	for (ref = f->inocache->nodes; ref && ref->next_in_ino; ref = ref->next_in_ino) {
		/* Work out whether it's a data node or a dirent node */
		if (ref_obsolete(ref)) {
			/* FIXME: On NAND flash we may need to read these */
			D1(printk(KERN_DEBUG "node at 0x%08x is obsoleted. Ignoring.\n", ref_offset(ref)));
			continue;
		}
		/* We can hold a pointer to a non-obsolete node without the spinlock,
		   but _obsolete_ nodes may disappear at any time, if the block
		   they're in gets erased */
		spin_unlock(&c->erase_completion_lock);

		cond_resched();

		/* FIXME: point() */
		err = jffs2_flash_read(c, (ref_offset(ref)), min_t(uint32_t, ref->totlen, sizeof(node)), &retlen, (void *)&node);
		if (err) {
			printk(KERN_WARNING "error %d reading node at 0x%08x in get_inode_nodes()\n", err, ref_offset(ref));
			goto free_out;
		}
			

			/* Check we've managed to read at least the common node header */
		if (retlen < min_t(uint32_t, ref->totlen, sizeof(node.u))) {
			printk(KERN_WARNING "short read in get_inode_nodes()\n");
			err = -EIO;
			goto free_out;
		}
			
		switch (je16_to_cpu(node.u.nodetype)) {
		case JFFS2_NODETYPE_DIRENT:
			D1(printk(KERN_DEBUG "Node at %08x (%d) is a dirent node\n", ref_offset(ref), ref_flags(ref)));
			if (ref_flags(ref) == REF_UNCHECKED) {
				printk(KERN_WARNING "BUG: Dirent node at 0x%08x never got checked? How?\n", ref_offset(ref));
				BUG();
			}
			if (retlen < sizeof(node.d)) {
				printk(KERN_WARNING "short read in get_inode_nodes()\n");
				err = -EIO;
				goto free_out;
			}
			/* sanity check */
			if (PAD((node.d.nsize + sizeof (node.d))) != PAD(je32_to_cpu (node.d.totlen))) {
				printk(KERN_NOTICE "jffs2_get_inode_nodes(): Illegal nsize in node at 0x%08x: nsize 0x%02x, totlen %04x\n",
				       ref_offset(ref), node.d.nsize, je32_to_cpu(node.d.totlen));
				jffs2_mark_node_obsolete(c, ref);
				spin_lock(&c->erase_completion_lock);
				continue;
			}
			if (je32_to_cpu(node.d.version) > *highest_version)
				*highest_version = je32_to_cpu(node.d.version);
			if (ref_obsolete(ref)) {
				/* Obsoleted. This cannot happen, surely? dwmw2 20020308 */
				printk(KERN_ERR "Dirent node at 0x%08x became obsolete while we weren't looking\n",
				       ref_offset(ref));
				BUG();
			}
			
			fd = jffs2_alloc_full_dirent(node.d.nsize+1);
			if (!fd) {
				err = -ENOMEM;
				goto free_out;
			}
			memset(fd,0,sizeof(struct jffs2_full_dirent) + node.d.nsize+1);
			fd->raw = ref;
			fd->version = je32_to_cpu(node.d.version);
			fd->ino = je32_to_cpu(node.d.ino);
			fd->type = node.d.type;

			/* Pick out the mctime of the latest dirent */
			if(fd->version > *mctime_ver) {
				*mctime_ver = fd->version;
				*latest_mctime = je32_to_cpu(node.d.mctime);
			}

			/* memcpy as much of the name as possible from the raw
			   dirent we've already read from the flash
			*/
			if (retlen > sizeof(struct jffs2_raw_dirent))
				memcpy(&fd->name[0], &node.d.name[0], min_t(uint32_t, node.d.nsize, (retlen-sizeof(struct jffs2_raw_dirent))));
				
			/* Do we need to copy any more of the name directly
			   from the flash?
			*/
			if (node.d.nsize + sizeof(struct jffs2_raw_dirent) > retlen) {
				/* FIXME: point() */
				int already = retlen - sizeof(struct jffs2_raw_dirent);
					
				err = jffs2_flash_read(c, (ref_offset(ref)) + retlen, 
						   node.d.nsize - already, &retlen, &fd->name[already]);
				if (!err && retlen != node.d.nsize - already)
					err = -EIO;
					
				if (err) {
					printk(KERN_WARNING "Read remainder of name in jffs2_get_inode_nodes(): error %d\n", err);
					jffs2_free_full_dirent(fd);
					goto free_out;
				}
			}
			fd->nhash = full_name_hash(fd->name, node.d.nsize);
			fd->next = NULL;
				/* Wheee. We now have a complete jffs2_full_dirent structure, with
				   the name in it and everything. Link it into the list 
				*/
			D1(printk(KERN_DEBUG "Adding fd \"%s\", ino #%u\n", fd->name, fd->ino));
			jffs2_add_fd_to_list(c, fd, &ret_fd);
			break;

		case JFFS2_NODETYPE_INODE:
			D1(printk(KERN_DEBUG "Node at %08x (%d) is a data node\n", ref_offset(ref), ref_flags(ref)));
			if (retlen < sizeof(node.i)) {
				printk(KERN_WARNING "read too short for dnode\n");
				err = -EIO;
				goto free_out;
			}
			if (je32_to_cpu(node.i.version) > *highest_version)
				*highest_version = je32_to_cpu(node.i.version);
			D1(printk(KERN_DEBUG "version %d, highest_version now %d\n", je32_to_cpu(node.i.version), *highest_version));

			if (ref_obsolete(ref)) {
				/* Obsoleted. This cannot happen, surely? dwmw2 20020308 */
				printk(KERN_ERR "Inode node at 0x%08x became obsolete while we weren't looking\n",
				       ref_offset(ref));
				BUG();
			}

			/* If we've never checked the CRCs on this node, check them now. */
			if (ref_flags(ref) == REF_UNCHECKED) {
				uint32_t crc;
				struct jffs2_eraseblock *jeb;

				crc = crc32(0, &node, sizeof(node.i)-8);
				if (crc != je32_to_cpu(node.i.node_crc)) {
					printk(KERN_NOTICE "jffs2_get_inode_nodes(): CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
					       ref_offset(ref), je32_to_cpu(node.i.node_crc), crc);
					jffs2_mark_node_obsolete(c, ref);
					spin_lock(&c->erase_completion_lock);
					continue;
				}
				
				/* sanity checks */
				if ( je32_to_cpu(node.i.offset) > je32_to_cpu(node.i.isize) ||
				     PAD(je32_to_cpu(node.i.csize) + sizeof (node.i)) != PAD(je32_to_cpu(node.i.totlen))) {
					printk(KERN_NOTICE "jffs2_get_inode_nodes(): Inode corrupted at 0x%08x, totlen %d, #ino  %d, version %d, isize %d, csize %d, dsize %d \n",
						ref_offset(ref),  je32_to_cpu(node.i.totlen),  je32_to_cpu(node.i.ino),
						je32_to_cpu(node.i.version),  je32_to_cpu(node.i.isize), 
						je32_to_cpu(node.i.csize), je32_to_cpu(node.i.dsize));
					jffs2_mark_node_obsolete(c, ref);
					spin_lock(&c->erase_completion_lock);
					continue;
				}

				if (node.i.compr != JFFS2_COMPR_ZERO && je32_to_cpu(node.i.csize)) {
					unsigned char *buf=NULL;
					uint32_t pointed = 0;
#ifndef __ECOS
					if (c->mtd->point) {
						err = c->mtd->point (c->mtd, ref_offset(ref) + sizeof(node.i), je32_to_cpu(node.i.csize),
								     &retlen, &buf);
						if (!err && retlen < je32_to_cpu(node.i.csize)) {
							D1(printk(KERN_DEBUG "MTD point returned len too short: 0x%zx\n", retlen));
							c->mtd->unpoint(c->mtd, buf, ref_offset(ref) + sizeof(node.i), je32_to_cpu(node.i.csize));
						} else if (err){
							D1(printk(KERN_DEBUG "MTD point failed %d\n", err));
						} else
							pointed = 1; /* succefully pointed to device */
					}
#endif					
					if(!pointed){
						buf = kmalloc(je32_to_cpu(node.i.csize), GFP_KERNEL);
						if (!buf)
							return -ENOMEM;
						
						err = jffs2_flash_read(c, ref_offset(ref) + sizeof(node.i), je32_to_cpu(node.i.csize),
								       &retlen, buf);
						if (!err && retlen != je32_to_cpu(node.i.csize))
							err = -EIO;
						if (err) {
							kfree(buf);
							return err;
						}
					}
					crc = crc32(0, buf, je32_to_cpu(node.i.csize));
					if(!pointed)
						kfree(buf);
#ifndef __ECOS
					else
						c->mtd->unpoint(c->mtd, buf, ref_offset(ref) + sizeof(node.i), je32_to_cpu(node.i.csize));
#endif

					if (crc != je32_to_cpu(node.i.data_crc)) {
						printk(KERN_NOTICE "jffs2_get_inode_nodes(): Data CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
						       ref_offset(ref), je32_to_cpu(node.i.data_crc), crc);
						jffs2_mark_node_obsolete(c, ref);
						spin_lock(&c->erase_completion_lock);
						continue;
					}
					
				}

				/* Mark the node as having been checked and fix the accounting accordingly */
				spin_lock(&c->erase_completion_lock);
				jeb = &c->blocks[ref->flash_offset / c->sector_size];
				jeb->used_size += ref->totlen;
				jeb->unchecked_size -= ref->totlen;
				c->used_size += ref->totlen;
				c->unchecked_size -= ref->totlen;

				/* If node covers at least a whole page, or if it starts at the 
				   beginning of a page and runs to the end of the file, or if 
				   it's a hole node, mark it REF_PRISTINE, else REF_NORMAL. 

				   If it's actually overlapped, it'll get made NORMAL (or OBSOLETE) 
				   when the overlapping node(s) get added to the tree anyway. 
				*/
				if ((je32_to_cpu(node.i.dsize) >= PAGE_CACHE_SIZE) ||
				    ( ((je32_to_cpu(node.i.offset)&(PAGE_CACHE_SIZE-1))==0) &&
				      (je32_to_cpu(node.i.dsize)+je32_to_cpu(node.i.offset) ==  je32_to_cpu(node.i.isize)))) {
					D1(printk(KERN_DEBUG "Marking node at 0x%08x REF_PRISTINE\n", ref_offset(ref)));
					ref->flash_offset = ref_offset(ref) | REF_PRISTINE;
				} else {
					D1(printk(KERN_DEBUG "Marking node at 0x%08x REF_NORMAL\n", ref_offset(ref)));
					ref->flash_offset = ref_offset(ref) | REF_NORMAL;
				}
				spin_unlock(&c->erase_completion_lock);
			}

			tn = jffs2_alloc_tmp_dnode_info();
			if (!tn) {
				D1(printk(KERN_DEBUG "alloc tn failed\n"));
				err = -ENOMEM;
				goto free_out;
			}

			tn->fn = jffs2_alloc_full_dnode();
			if (!tn->fn) {
				D1(printk(KERN_DEBUG "alloc fn failed\n"));
				err = -ENOMEM;
				jffs2_free_tmp_dnode_info(tn);
				goto free_out;
			}
			tn->version = je32_to_cpu(node.i.version);
			tn->fn->ofs = je32_to_cpu(node.i.offset);
			/* There was a bug where we wrote hole nodes out with
			   csize/dsize swapped. Deal with it */
			if (node.i.compr == JFFS2_COMPR_ZERO && !je32_to_cpu(node.i.dsize) && je32_to_cpu(node.i.csize))
				tn->fn->size = je32_to_cpu(node.i.csize);
			else // normal case...
				tn->fn->size = je32_to_cpu(node.i.dsize);
			tn->fn->raw = ref;
			D1(printk(KERN_DEBUG "dnode @%08x: ver %u, offset %04x, dsize %04x\n",
				  ref_offset(ref), je32_to_cpu(node.i.version),
				  je32_to_cpu(node.i.offset), je32_to_cpu(node.i.dsize)));
			jffs2_add_tn_to_list(tn, &ret_tn);
			break;

		default:
			if (ref_flags(ref) == REF_UNCHECKED) {
				struct jffs2_eraseblock *jeb;

				printk(KERN_ERR "Eep. Unknown node type %04x at %08x was marked REF_UNCHECKED\n",
				       je16_to_cpu(node.u.nodetype), ref_offset(ref));

				/* Mark the node as having been checked and fix the accounting accordingly */
				spin_lock(&c->erase_completion_lock);
				jeb = &c->blocks[ref->flash_offset / c->sector_size];
				jeb->used_size += ref->totlen;
				jeb->unchecked_size -= ref->totlen;
				c->used_size += ref->totlen;
				c->unchecked_size -= ref->totlen;

				mark_ref_normal(ref);
				spin_unlock(&c->erase_completion_lock);
			}
			node.u.nodetype = cpu_to_je16(JFFS2_NODE_ACCURATE | je16_to_cpu(node.u.nodetype));
			if (crc32(0, &node, sizeof(struct jffs2_unknown_node)-4) != je32_to_cpu(node.u.hdr_crc)) {
				/* Hmmm. This should have been caught at scan time. */
				printk(KERN_ERR "Node header CRC failed at %08x. But it must have been OK earlier.\n",
				       ref_offset(ref));
				printk(KERN_ERR "Node was: { %04x, %04x, %08x, %08x }\n", 
				       je16_to_cpu(node.u.magic), je16_to_cpu(node.u.nodetype), je32_to_cpu(node.u.totlen),
				       je32_to_cpu(node.u.hdr_crc));
				jffs2_mark_node_obsolete(c, ref);
			} else switch(je16_to_cpu(node.u.nodetype) & JFFS2_COMPAT_MASK) {
			case JFFS2_FEATURE_INCOMPAT:
				printk(KERN_NOTICE "Unknown INCOMPAT nodetype %04X at %08x\n", je16_to_cpu(node.u.nodetype), ref_offset(ref));
				/* EEP */
				BUG();
				break;
			case JFFS2_FEATURE_ROCOMPAT:
				printk(KERN_NOTICE "Unknown ROCOMPAT nodetype %04X at %08x\n", je16_to_cpu(node.u.nodetype), ref_offset(ref));
				if (!(c->flags & JFFS2_SB_FLAG_RO))
					BUG();
				break;
			case JFFS2_FEATURE_RWCOMPAT_COPY:
				printk(KERN_NOTICE "Unknown RWCOMPAT_COPY nodetype %04X at %08x\n", je16_to_cpu(node.u.nodetype), ref_offset(ref));
				break;
			case JFFS2_FEATURE_RWCOMPAT_DELETE:
				printk(KERN_NOTICE "Unknown RWCOMPAT_DELETE nodetype %04X at %08x\n", je16_to_cpu(node.u.nodetype), ref_offset(ref));
				jffs2_mark_node_obsolete(c, ref);
				break;
			}

		}
		spin_lock(&c->erase_completion_lock);

	}
	spin_unlock(&c->erase_completion_lock);
	*tnp = ret_tn;
	*fdp = ret_fd;

	return 0;

 free_out:
	jffs2_free_tmp_dnode_info_list(ret_tn);
	jffs2_free_full_dirent_list(ret_fd);
	return err;
}

void jffs2_set_inocache_state(struct jffs2_sb_info *c, struct jffs2_inode_cache *ic, int state)
{
	spin_lock(&c->inocache_lock);
	ic->state = state;
	wake_up(&c->inocache_wq);
	spin_unlock(&c->inocache_lock);
}

/* During mount, this needs no locking. During normal operation, its
   callers want to do other stuff while still holding the inocache_lock.
   Rather than introducing special case get_ino_cache functions or 
   callbacks, we just let the caller do the locking itself. */
   
struct jffs2_inode_cache *jffs2_get_ino_cache(struct jffs2_sb_info *c, uint32_t ino)
{
	struct jffs2_inode_cache *ret;

	D2(printk(KERN_DEBUG "jffs2_get_ino_cache(): ino %u\n", ino));

	ret = c->inocache_list[ino % INOCACHE_HASHSIZE];
	while (ret && ret->ino < ino) {
		ret = ret->next;
	}
	
	if (ret && ret->ino != ino)
		ret = NULL;

	D2(printk(KERN_DEBUG "jffs2_get_ino_cache found %p for ino %u\n", ret, ino));
	return ret;
}

void jffs2_add_ino_cache (struct jffs2_sb_info *c, struct jffs2_inode_cache *new)
{
	struct jffs2_inode_cache **prev;
	D2(printk(KERN_DEBUG "jffs2_add_ino_cache: Add %p (ino #%u)\n", new, new->ino));
	spin_lock(&c->inocache_lock);
	
	prev = &c->inocache_list[new->ino % INOCACHE_HASHSIZE];

	while ((*prev) && (*prev)->ino < new->ino) {
		prev = &(*prev)->next;
	}
	new->next = *prev;
	*prev = new;

	spin_unlock(&c->inocache_lock);
}

void jffs2_del_ino_cache(struct jffs2_sb_info *c, struct jffs2_inode_cache *old)
{
	struct jffs2_inode_cache **prev;
	D2(printk(KERN_DEBUG "jffs2_del_ino_cache: Del %p (ino #%u)\n", old, old->ino));
	spin_lock(&c->inocache_lock);
	
	prev = &c->inocache_list[old->ino % INOCACHE_HASHSIZE];
	
	while ((*prev) && (*prev)->ino < old->ino) {
		prev = &(*prev)->next;
	}
	if ((*prev) == old) {
		*prev = old->next;
	}

	spin_unlock(&c->inocache_lock);
}

void jffs2_free_ino_caches(struct jffs2_sb_info *c)
{
	int i;
	struct jffs2_inode_cache *this, *next;
	
	for (i=0; i<INOCACHE_HASHSIZE; i++) {
		this = c->inocache_list[i];
		while (this) {
			next = this->next;
			D2(printk(KERN_DEBUG "jffs2_free_ino_caches: Freeing ino #%u at %p\n", this->ino, this));
			jffs2_free_inode_cache(this);
			this = next;
		}
		c->inocache_list[i] = NULL;
	}
}

void jffs2_free_raw_node_refs(struct jffs2_sb_info *c)
{
	int i;
	struct jffs2_raw_node_ref *this, *next;

	for (i=0; i<c->nr_blocks; i++) {
		this = c->blocks[i].first_node;
		while(this) {
			next = this->next_phys;
			jffs2_free_raw_node_ref(this);
			this = next;
		}
		c->blocks[i].first_node = c->blocks[i].last_node = NULL;
	}
}
	
struct jffs2_node_frag *jffs2_lookup_node_frag(struct rb_root *fragtree, uint32_t offset)
{
	/* The common case in lookup is that there will be a node 
	   which precisely matches. So we go looking for that first */
	struct rb_node *next;
	struct jffs2_node_frag *prev = NULL;
	struct jffs2_node_frag *frag = NULL;

	D2(printk(KERN_DEBUG "jffs2_lookup_node_frag(%p, %d)\n", fragtree, offset));

	next = fragtree->rb_node;

	while(next) {
		frag = rb_entry(next, struct jffs2_node_frag, rb);

		D2(printk(KERN_DEBUG "Considering frag %d-%d (%p). left %p, right %p\n",
			  frag->ofs, frag->ofs+frag->size, frag, frag->rb.rb_left, frag->rb.rb_right));
		if (frag->ofs + frag->size <= offset) {
			D2(printk(KERN_DEBUG "Going right from frag %d-%d, before the region we care about\n",
				  frag->ofs, frag->ofs+frag->size));
			/* Remember the closest smaller match on the way down */
			if (!prev || frag->ofs > prev->ofs)
				prev = frag;
			next = frag->rb.rb_right;
		} else if (frag->ofs > offset) {
			D2(printk(KERN_DEBUG "Going left from frag %d-%d, after the region we care about\n",
				  frag->ofs, frag->ofs+frag->size));
			next = frag->rb.rb_left;
		} else {
			D2(printk(KERN_DEBUG "Returning frag %d,%d, matched\n",
				  frag->ofs, frag->ofs+frag->size));
			return frag;
		}
	}

	/* Exact match not found. Go back up looking at each parent,
	   and return the closest smaller one */

	if (prev)
		D2(printk(KERN_DEBUG "No match. Returning frag %d,%d, closest previous\n",
			  prev->ofs, prev->ofs+prev->size));
	else 
		D2(printk(KERN_DEBUG "Returning NULL, empty fragtree\n"));
	
	return prev;
}

/* Pass 'c' argument to indicate that nodes should be marked obsolete as
   they're killed. */
void jffs2_kill_fragtree(struct rb_root *root, struct jffs2_sb_info *c)
{
	struct jffs2_node_frag *frag;
	struct jffs2_node_frag *parent;

	if (!root->rb_node)
		return;

	frag = (rb_entry(root->rb_node, struct jffs2_node_frag, rb));

	while(frag) {
		if (frag->rb.rb_left) {
			D2(printk(KERN_DEBUG "Going left from frag (%p) %d-%d\n", 
				  frag, frag->ofs, frag->ofs+frag->size));
			frag = frag_left(frag);
			continue;
		}
		if (frag->rb.rb_right) {
			D2(printk(KERN_DEBUG "Going right from frag (%p) %d-%d\n", 
				  frag, frag->ofs, frag->ofs+frag->size));
			frag = frag_right(frag);
			continue;
		}

		D2(printk(KERN_DEBUG "jffs2_kill_fragtree: frag at 0x%x-0x%x: node %p, frags %d--\n",
			  frag->ofs, frag->ofs+frag->size, frag->node,
			  frag->node?frag->node->frags:0));
			
		if (frag->node && !(--frag->node->frags)) {
			/* Not a hole, and it's the final remaining frag 
			   of this node. Free the node */
			if (c)
				jffs2_mark_node_obsolete(c, frag->node->raw);
			
			jffs2_free_full_dnode(frag->node);
		}
		parent = frag_parent(frag);
		if (parent) {
			if (frag_left(parent) == frag)
				parent->rb.rb_left = NULL;
			else 
				parent->rb.rb_right = NULL;
		}

		jffs2_free_node_frag(frag);
		frag = parent;
	}
}

void jffs2_fragtree_insert(struct jffs2_node_frag *newfrag, struct jffs2_node_frag *base)
{
	struct rb_node *parent = &base->rb;
	struct rb_node **link = &parent;

	D2(printk(KERN_DEBUG "jffs2_fragtree_insert(%p; %d-%d, %p)\n", newfrag, 
		  newfrag->ofs, newfrag->ofs+newfrag->size, base));

	while (*link) {
		parent = *link;
		base = rb_entry(parent, struct jffs2_node_frag, rb);
	
		D2(printk(KERN_DEBUG "fragtree_insert considering frag at 0x%x\n", base->ofs));
		if (newfrag->ofs > base->ofs)
			link = &base->rb.rb_right;
		else if (newfrag->ofs < base->ofs)
			link = &base->rb.rb_left;
		else {
			printk(KERN_CRIT "Duplicate frag at %08x (%p,%p)\n", newfrag->ofs, newfrag, base);
			BUG();
		}
	}

	rb_link_node(&newfrag->rb, &base->rb, link);
}