[JFFS2] Build fragtree in reverse order

Instead of building fragtree starting from node with the smallest version
number, start from the highest. This helps to avoid reading and checking
obsolete nodes.

Signed-off-by: Artem B. Bityutskiy <dedekind@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 570 insertions, 67 deletions

diff --git a/fs/jffs2/nodelist.c b/fs/jffs2/nodelist.c
index 0cf5e6f11989..390ce06ab1a7 100644
--- a/fs/jffs2/nodelist.c
+++ b/fs/jffs2/nodelist.c
@@ -7,7 +7,7 @@
  *
  * For licensing information, see the file 'LICENCE' in this directory.
  *
- * $Id: nodelist.c,v 1.103 2005/07/31 08:20:44 dedekind Exp $
+ * $Id: nodelist.c,v 1.104 2005/08/01 12:05:19 dedekind Exp $
  *
  */
 
@@ -59,7 +59,7 @@ void jffs2_truncate_fragtree(struct jffs2_sb_info *c, struct rb_root *list, uint
 
 	/* We know frag->ofs <= size. That's what lookup does for us */
 	if (frag && frag->ofs != size) {
-		if (frag->ofs+frag->size >= size) {
+		if (frag->ofs+frag->size > size) {
 			JFFS2_DBG_FRAGTREE2("truncating frag 0x%08x-0x%08x\n", frag->ofs, frag->ofs+frag->size);
 			frag->size = size - frag->ofs;
 		}
@@ -73,6 +73,20 @@ void jffs2_truncate_fragtree(struct jffs2_sb_info *c, struct rb_root *list, uint
 		jffs2_obsolete_node_frag(c, frag);
 		frag = next;
 	}
+
+	if (size == 0)
+		return;
+
+	/* 
+	 * If the last fragment starts at the RAM page boundary, it is
+	 * REF_PRISTINE irrespective of its size.
+	 */
+	frag = frag_last(list);
+	if ((frag->ofs & (PAGE_CACHE_SIZE - 1)) == 0) {
+		JFFS2_DBG_FRAGTREE2("marking the last fragment 0x%08x-0x%08x REF_PRISTINE.\n",
+			frag->ofs, frag->ofs + frag->size); 
+		frag->node->raw->flash_offset = ref_offset(frag->node->raw) | REF_PRISTINE;
+	}
 }
 
 void jffs2_obsolete_node_frag(struct jffs2_sb_info *c, struct jffs2_node_frag *this)
@@ -120,14 +134,82 @@ static void jffs2_fragtree_insert(struct jffs2_node_frag *newfrag, struct jffs2_
 	rb_link_node(&newfrag->rb, &base->rb, link);
 }
 
+/*
+ * Allocate and initializes a new fragment.
+ */
+static inline struct jffs2_node_frag * new_fragment(struct jffs2_full_dnode *fn, uint32_t ofs, uint32_t size)
+{
+	struct jffs2_node_frag *newfrag;
+	
+	newfrag = jffs2_alloc_node_frag();
+	if (likely(newfrag)) {
+		newfrag->ofs = ofs;
+		newfrag->size = size;
+		newfrag->node = fn;
+	} else {
+		JFFS2_ERROR("cannot allocate a jffs2_node_frag object\n");
+	}
+
+	return newfrag;
+}
+
+/*
+ * Called when there is no overlapping fragment exist. Inserts a hole before the new
+ * fragment and inserts the new fragment to the fragtree.
+ */
+static int no_overlapping_node(struct jffs2_sb_info *c, struct rb_root *root,
+		 	       struct jffs2_node_frag *newfrag,
+			       struct jffs2_node_frag *this, uint32_t lastend)
+{
+	if (lastend < newfrag->node->ofs) {
+		/* put a hole in before the new fragment */
+		struct jffs2_node_frag *holefrag;
+
+		holefrag= new_fragment(NULL, lastend, newfrag->node->ofs - lastend);
+		if (unlikely(!holefrag)) {
+			jffs2_free_node_frag(newfrag);
+			return -ENOMEM;
+		}
+
+		if (this) {
+			/* By definition, the 'this' node has no right-hand child, 
+			   because there are no frags with offset greater than it.
+			   So that's where we want to put the hole */
+			JFFS2_DBG_FRAGTREE2("add hole frag %u-%u on the right of the new frag.\n",
+				holefrag->ofs, holefrag->ofs + holefrag->size);
+			rb_link_node(&holefrag->rb, &this->rb, &this->rb.rb_right);
+		} else {
+			JFFS2_DBG_FRAGTREE2("Add hole frag %u-%u to the root of the tree.\n",
+				holefrag->ofs, holefrag->ofs + holefrag->size);
+			rb_link_node(&holefrag->rb, NULL, &root->rb_node);
+		}
+		rb_insert_color(&holefrag->rb, root);
+		this = holefrag;
+	}
+	
+	if (this) {
+		/* By definition, the 'this' node has no right-hand child, 
+		   because there are no frags with offset greater than it.
+		   So that's where we want to put new fragment */
+		JFFS2_DBG_FRAGTREE2("add the new node at the right\n");
+		rb_link_node(&newfrag->rb, &this->rb, &this->rb.rb_right);			
+	} else {
+		JFFS2_DBG_FRAGTREE2("insert the new node at the root of the tree\n");
+		rb_link_node(&newfrag->rb, NULL, &root->rb_node);
+	}
+	rb_insert_color(&newfrag->rb, root);
+
+	return 0;
+}
+
 /* Doesn't set inode->i_size */
-static int jffs2_add_frag_to_fragtree(struct jffs2_sb_info *c, struct rb_root *list, struct jffs2_node_frag *newfrag)
+static int jffs2_add_frag_to_fragtree(struct jffs2_sb_info *c, struct rb_root *root, struct jffs2_node_frag *newfrag)
 {
 	struct jffs2_node_frag *this;
 	uint32_t lastend;
 
 	/* Skip all the nodes which are completed before this one starts */
-	this = jffs2_lookup_node_frag(list, newfrag->node->ofs);
+	this = jffs2_lookup_node_frag(root, newfrag->node->ofs);
 
 	if (this) {
 		JFFS2_DBG_FRAGTREE2("lookup gave frag 0x%04x-0x%04x; phys 0x%08x (*%p)\n",
@@ -138,7 +220,7 @@ static int jffs2_add_frag_to_fragtree(struct jffs2_sb_info *c, struct rb_root *l
 		lastend = 0;
 	}
 			  
-	/* See if we ran off the end of the list */
+	/* See if we ran off the end of the fragtree */
 	if (lastend <= newfrag->ofs) {
 		/* We did */
 
@@ -152,45 +234,16 @@ static int jffs2_add_frag_to_fragtree(struct jffs2_sb_info *c, struct rb_root *l
 			mark_ref_normal(newfrag->node->raw);
 		}
 
-		if (lastend < newfrag->node->ofs) {
-			/* ... and we need to put a hole in before the new node */
-			struct jffs2_node_frag *holefrag = jffs2_alloc_node_frag();
-			if (!holefrag) {
-				jffs2_free_node_frag(newfrag);
-				return -ENOMEM;
-			}
-			holefrag->ofs = lastend;
-			holefrag->size = newfrag->node->ofs - lastend;
-			holefrag->node = NULL;
-			if (this) {
-				/* By definition, the 'this' node has no right-hand child, 
-				   because there are no frags with offset greater than it.
-				   So that's where we want to put the hole */
-				JFFS2_DBG_FRAGTREE2("adding hole frag (%p) on right of node at (%p)\n", holefrag, this);
-				rb_link_node(&holefrag->rb, &this->rb, &this->rb.rb_right);
-			} else {
-				JFFS2_DBG_FRAGTREE2("adding hole frag (%p) at root of tree\n", holefrag);
-				rb_link_node(&holefrag->rb, NULL, &list->rb_node);
-			}
-			rb_insert_color(&holefrag->rb, list);
-			this = holefrag;
-		}
-		if (this) {
-			/* By definition, the 'this' node has no right-hand child, 
-			   because there are no frags with offset greater than it.
-			   So that's where we want to put new fragment */
-			JFFS2_DBG_FRAGTREE2("adding new frag (%p) on right of node at (%p)\n", newfrag, this);
-			rb_link_node(&newfrag->rb, &this->rb, &this->rb.rb_right);			
-		} else {
-			JFFS2_DBG_FRAGTREE2("adding new frag (%p) at root of tree\n", newfrag);
-			rb_link_node(&newfrag->rb, NULL, &list->rb_node);
-		}
-		rb_insert_color(&newfrag->rb, list);
-		return 0;
+		return no_overlapping_node(c, root, newfrag, this, lastend);
 	}
 
-	JFFS2_DBG_FRAGTREE2("dealing with frag 0x%04x-0x%04x; phys 0x%08x (*%p)\n", 
-		  this->ofs, this->ofs+this->size, this->node?(ref_offset(this->node->raw)):0xffffffff, this);
+	if (this->node)
+		JFFS2_DBG_FRAGTREE2("dealing with frag %u-%u, phys %#08x(%d).\n",
+		this->ofs, this->ofs + this->size,
+		ref_offset(this->node->raw), ref_flags(this->node->raw));
+	else
+		JFFS2_DBG_FRAGTREE2("dealing with hole frag %u-%u.\n",
+		this->ofs, this->ofs + this->size);
 
 	/* OK. 'this' is pointing at the first frag that newfrag->ofs at least partially obsoletes,
 	 * - i.e. newfrag->ofs < this->ofs+this->size && newfrag->ofs >= this->ofs  
@@ -206,11 +259,8 @@ static int jffs2_add_frag_to_fragtree(struct jffs2_sb_info *c, struct rb_root *l
 
 		if (this->ofs + this->size > newfrag->ofs + newfrag->size) {
 			/* The new node splits 'this' frag into two */
-			struct jffs2_node_frag *newfrag2 = jffs2_alloc_node_frag();
-			if (!newfrag2) {
-				jffs2_free_node_frag(newfrag);
-				return -ENOMEM;
-			}
+			struct jffs2_node_frag *newfrag2;
+
 			if (this->node)
 				JFFS2_DBG_FRAGTREE2("split old frag 0x%04x-0x%04x, phys 0x%08x\n",
 					this->ofs, this->ofs+this->size, ref_offset(this->node->raw));
@@ -219,9 +269,10 @@ static int jffs2_add_frag_to_fragtree(struct jffs2_sb_info *c, struct rb_root *l
 					this->ofs, this->ofs+this->size, ref_offset(this->node->raw));
 			
 			/* New second frag pointing to this's node */
-			newfrag2->ofs = newfrag->ofs + newfrag->size;
-			newfrag2->size = (this->ofs+this->size) - newfrag2->ofs;
-			newfrag2->node = this->node;
+			newfrag2 = new_fragment(this->node, newfrag->ofs + newfrag->size,
+						this->ofs + this->size - newfrag->ofs - newfrag->size);
+			if (unlikely(!newfrag2))
+				return -ENOMEM;
 			if (this->node)
 				this->node->frags++;
 
@@ -235,10 +286,10 @@ static int jffs2_add_frag_to_fragtree(struct jffs2_sb_info *c, struct rb_root *l
 			   'this' to insert newfrag, and a tree insert
 			   from newfrag to insert newfrag2. */
 			jffs2_fragtree_insert(newfrag, this);
-			rb_insert_color(&newfrag->rb, list);
+			rb_insert_color(&newfrag->rb, root);
 			
 			jffs2_fragtree_insert(newfrag2, newfrag);
-			rb_insert_color(&newfrag2->rb, list);
+			rb_insert_color(&newfrag2->rb, root);
 			
 			return 0;
 		}
@@ -247,14 +298,14 @@ static int jffs2_add_frag_to_fragtree(struct jffs2_sb_info *c, struct rb_root *l
 
 		/* Again, we know it lives down here in the tree */
 		jffs2_fragtree_insert(newfrag, this);
-		rb_insert_color(&newfrag->rb, list);
+		rb_insert_color(&newfrag->rb, root);
 	} else {
 		/* New frag starts at the same point as 'this' used to. Replace 
 		   it in the tree without doing a delete and insertion */
 		JFFS2_DBG_FRAGTREE2("inserting newfrag (*%p),%d-%d in before 'this' (*%p),%d-%d\n",
 			  newfrag, newfrag->ofs, newfrag->ofs+newfrag->size, this, this->ofs, this->ofs+this->size);
 	
-		rb_replace_node(&this->rb, &newfrag->rb, list);
+		rb_replace_node(&this->rb, &newfrag->rb, root);
 		
 		if (newfrag->ofs + newfrag->size >= this->ofs+this->size) {
 			JFFS2_DBG_FRAGTREE2("obsoleting node frag %p (%x-%x)\n", this, this->ofs, this->ofs+this->size);
@@ -264,7 +315,7 @@ static int jffs2_add_frag_to_fragtree(struct jffs2_sb_info *c, struct rb_root *l
 			this->size -= newfrag->size;
 
 			jffs2_fragtree_insert(this, newfrag);
-			rb_insert_color(&this->rb, list);
+			rb_insert_color(&this->rb, root);
 			return 0;
 		}
 	}
@@ -275,15 +326,15 @@ static int jffs2_add_frag_to_fragtree(struct jffs2_sb_info *c, struct rb_root *l
 		/* 'this' frag is obsoleted completely. */
 		JFFS2_DBG_FRAGTREE2("obsoleting node frag %p (%x-%x) and removing from tree\n",
 			this, this->ofs, this->ofs+this->size);
-		rb_erase(&this->rb, list);
+		rb_erase(&this->rb, root);
 		jffs2_obsolete_node_frag(c, this);
 	}
 	/* Now we're pointing at the first frag which isn't totally obsoleted by 
 	   the new frag */
 
-	if (!this || newfrag->ofs + newfrag->size == this->ofs) {
+	if (!this || newfrag->ofs + newfrag->size == this->ofs)
 		return 0;
-	}
+
 	/* Still some overlap but we don't need to move it in the tree */
 	this->size = (this->ofs + this->size) - (newfrag->ofs + newfrag->size);
 	this->ofs = newfrag->ofs + newfrag->size;
@@ -296,8 +347,9 @@ static int jffs2_add_frag_to_fragtree(struct jffs2_sb_info *c, struct rb_root *l
 	return 0;
 }
 
-/* Given an inode, probably with existing list of fragments, add the new node
- * to the fragment list.
+/* 
+ * Given an inode, probably with existing tree of fragments, add the new node
+ * to the fragment tree.
  */
 int jffs2_add_full_dnode_to_inode(struct jffs2_sb_info *c, struct jffs2_inode_info *f, struct jffs2_full_dnode *fn)
 {
@@ -307,18 +359,14 @@ int jffs2_add_full_dnode_to_inode(struct jffs2_sb_info *c, struct jffs2_inode_in
 	if (unlikely(!fn->size))
 		return 0;
 
-	newfrag = jffs2_alloc_node_frag();
+	newfrag = new_fragment(fn, fn->ofs, fn->size);
 	if (unlikely(!newfrag))
 		return -ENOMEM;
+	newfrag->node->frags = 1;
 
 	JFFS2_DBG_FRAGTREE("adding node %#04x-%#04x @0x%08x on flash, newfrag *%p\n",
 		  fn->ofs, fn->ofs+fn->size, ref_offset(fn->raw), newfrag);
 	
-	newfrag->ofs = fn->ofs;
-	newfrag->size = fn->size;
-	newfrag->node = fn;
-	newfrag->node->frags = 1;
-
 	ret = jffs2_add_frag_to_fragtree(c, &f->fragtree, newfrag);
 	if (unlikely(ret))
 		return ret;
@@ -344,10 +392,465 @@ int jffs2_add_full_dnode_to_inode(struct jffs2_sb_info *c, struct jffs2_inode_in
 		}
 	}
 	jffs2_dbg_fragtree_paranoia_check_nolock(f);
-	jffs2_dbg_dump_fragtree_nolock(f);
+
+	return 0;
+}
+
+/*
+ * Check the data CRC of the node.
+ *
+ * Returns: 0 if the data CRC is correct;
+ * 	    1 - if incorrect;
+ *	    error code if an error occured.
+ */
+static int check_node_data(struct jffs2_sb_info *c, struct jffs2_tmp_dnode_info *tn)
+{
+	struct jffs2_raw_node_ref *ref = tn->fn->raw;
+	int err = 0, pointed = 0;
+	struct jffs2_eraseblock *jeb;
+	unsigned char *buffer;
+	uint32_t crc, ofs, retlen, len;
+
+	BUG_ON(tn->csize == 0);
+
+	/* Calculate how many bytes were already checked */
+	ofs = ref_offset(ref) + sizeof(struct jffs2_raw_inode);
+	len = ofs - (ofs & (PAGE_CACHE_SIZE - 1));
+	len = c->wbuf_pagesize - len;
+
+	if (len >= tn->csize) {
+		JFFS2_DBG_READINODE("no need to check node at %#08x, data length %u, data starts at %#08x - it has already been checked.\n",
+			ref_offset(ref), tn->csize, ofs);
+		goto adj_acc;
+	}
+	
+	ofs += len;
+	len = tn->csize - len;
+	
+	JFFS2_DBG_READINODE("check node at %#08x, data length %u, partial CRC %#08x, correct CRC %#08x, data starts at %#08x, start checking from %#08x - %u bytes.\n",
+		ref_offset(ref), tn->csize, tn->partial_crc, tn->data_crc, ofs - len, ofs, len);
+	
+#ifndef __ECOS
+	/* TODO: instead, incapsulate point() stuff to jffs2_flash_read(),
+	 * adding and jffs2_flash_read_end() interface. */
+	if (c->mtd->point) {
+		err = c->mtd->point(c->mtd, ofs, len, &retlen, &buffer);
+		if (!err && retlen < tn->csize) {
+			JFFS2_WARNING("MTD point returned len too short: %u instead of %u.\n", retlen, tn->csize);
+			c->mtd->unpoint(c->mtd, buffer, ofs, len);
+		} else if (err)
+			JFFS2_WARNING("MTD point failed: error code %d.\n", err);
+		else
+			pointed = 1; /* succefully pointed to device */
+	}
+#endif
+	
+	if (!pointed) {
+		buffer = kmalloc(len, GFP_KERNEL);
+		if (unlikely(!buffer))
+			return -ENOMEM;
+			
+		/* TODO: this is very frequent pattern, make it a separate
+		 * routine */
+		err = jffs2_flash_read(c, ofs, len, &retlen, buffer);
+		if (err) {
+			JFFS2_ERROR("can not read %d bytes from 0x%08x, error code: %d.\n", len, ofs, err);
+			goto free_out;
+		}
+			
+		if (retlen != len) {
+			JFFS2_ERROR("short read at %#08x: %d instead of %d.\n", ofs, retlen, len);
+			err = -EIO;
+			goto free_out;
+		}
+	}
+
+	/* Continue calculating CRC */
+	crc = crc32(tn->partial_crc, buffer, len);
+	if(!pointed)
+		kfree(buffer);
+#ifndef __ECOS
+	else
+		c->mtd->unpoint(c->mtd, buffer, ofs, len);
+#endif
+
+	if (crc != tn->data_crc) {
+		JFFS2_NOTICE("drong data CRC in data node at 0x%08x: read %#08x, calculated %#08x.\n",
+			ofs, tn->data_crc, crc);
+		return 1;
+	}
+
+adj_acc:
+	jeb = &c->blocks[ref->flash_offset / c->sector_size];
+	len = ref_totlen(c, jeb, ref);
+
+	/* 
+	 * Mark the node as having been checked and fix the
+	 * accounting accordingly.
+	 */
+	spin_lock(&c->erase_completion_lock);
+	jeb->used_size += len;
+	jeb->unchecked_size -= len;
+	c->used_size += len;
+	c->unchecked_size -= len;
+	spin_unlock(&c->erase_completion_lock);
+
 	return 0;
+
+free_out:
+	if(!pointed)
+		kfree(buffer);
+#ifndef __ECOS
+	else
+		c->mtd->unpoint(c->mtd, buffer, ofs, len);
+#endif
+	return err;
 }
 
+/*
+ * Helper function for jffs2_add_older_frag_to_fragtree().
+ *
+ * Checks the node if we are in the checking stage.
+ */
+static inline int check_node(struct jffs2_sb_info *c, struct jffs2_inode_info *f, struct jffs2_tmp_dnode_info *tn)
+{
+	int ret;
+	
+	BUG_ON(ref_obsolete(tn->fn->raw));
+
+	/* We only check the data CRC of unchecked nodes */
+	if (ref_flags(tn->fn->raw) != REF_UNCHECKED)
+		return 0;
+	
+	JFFS2_DBG_FRAGTREE2("check node %u-%u, phys offs %#08x.\n",
+		tn->fn->ofs, tn->fn->ofs + tn->fn->size,
+		ref_offset(tn->fn->raw));
+
+	ret = check_node_data(c, tn);
+	if (unlikely(ret < 0)) {
+		JFFS2_ERROR("check_node_data() returned error: %d.\n",
+			ret);
+	} else if (unlikely(ret > 0)) {
+		JFFS2_DBG_FRAGTREE2("CRC error, mark it obsolete.\n");
+		jffs2_mark_node_obsolete(c, tn->fn->raw);
+	}
+
+	return ret;
+}
+
+/* 
+ * Helper function for jffs2_add_older_frag_to_fragtree().
+ *
+ * Called when the new fragment that is being inserted
+ * splits a hole fragment.
+ */
+static int split_hole(struct jffs2_sb_info *c, struct rb_root *root,
+		      struct jffs2_node_frag *newfrag, struct jffs2_node_frag *hole)
+{
+	JFFS2_DBG_FRAGTREE2("fragment %#04x-%#04x splits the hole %#04x-%#04x\n",
+		newfrag->ofs, newfrag->ofs + newfrag->size, hole->ofs, hole->ofs + hole->size);
+
+	if (hole->ofs == newfrag->ofs) {
+		/* 
+		 * Well, the new fragment actually starts at the same offset as
+		 * the hole.
+		 */
+		if (hole->ofs + hole->size > newfrag->ofs + newfrag->size) {
+			/* 
+			 * We replace the overlapped left part of the hole by
+			 * the new node.
+			 */
+			
+			JFFS2_DBG_FRAGTREE2("insert fragment %#04x-%#04x and cut the left part of the hole\n",
+				newfrag->ofs, newfrag->ofs + newfrag->size);
+			rb_replace_node(&hole->rb, &newfrag->rb, root);
+			
+			hole->ofs += newfrag->size;
+			hole->size -= newfrag->size;
+			
+			/* 
+			 * We know that 'hole' should be the right hand
+			 * fragment.
+			 */
+			jffs2_fragtree_insert(hole, newfrag);
+			rb_insert_color(&hole->rb, root);
+		} else {
+			/* 
+			 * Ah, the new fragment is of the same size as the hole.
+			 * Relace the hole by it.
+			 */
+			JFFS2_DBG_FRAGTREE2("insert fragment %#04x-%#04x and overwrite hole\n",
+				newfrag->ofs, newfrag->ofs + newfrag->size);
+			rb_replace_node(&hole->rb, &newfrag->rb, root);
+			jffs2_free_node_frag(hole);
+		}
+	} else {
+		/* The new fragment lefts some hole space at the left */
+		
+		struct jffs2_node_frag * newfrag2 = NULL;
+
+		if (hole->ofs + hole->size > newfrag->ofs + newfrag->size) {
+			/* The new frag also lefts some space at the right */
+			newfrag2 = new_fragment(NULL, newfrag->ofs +
+				newfrag->size, hole->ofs + hole->size
+				- newfrag->ofs - newfrag->size);
+			if (unlikely(!newfrag2)) {
+				jffs2_free_node_frag(newfrag);
+				return -ENOMEM;
+			}
+		}
+
+		hole->size = newfrag->ofs - hole->ofs;
+		JFFS2_DBG_FRAGTREE2("left the hole %#04x-%#04x at the left and inserd fragment %#04x-%#04x\n",
+			hole->ofs, hole->ofs + hole->size, newfrag->ofs, newfrag->ofs + newfrag->size);
+
+		jffs2_fragtree_insert(newfrag, hole);
+		rb_insert_color(&newfrag->rb, root);
+		
+		if (newfrag2) {
+			JFFS2_DBG_FRAGTREE2("left the hole %#04x-%#04x at the right\n",
+				newfrag2->ofs, newfrag2->ofs + newfrag2->size);
+			jffs2_fragtree_insert(newfrag2, newfrag);
+			rb_insert_color(&newfrag2->rb, root);
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * This function is used when we build inode. It expects the nodes are passed
+ * in the decreasing version order. The whole point of this is to improve the
+ * inodes checking on NAND: we check the nodes' data CRC only when they are not
+ * obsoleted. Previously, add_frag_to_fragtree() function was used and
+ * nodes were passed to it in the increasing version ordes and CRCs of all
+ * nodes were checked.
+ *
+ * Note: tn->fn->size shouldn't be zero.
+ *
+ * Returns 0 if the node was inserted
+ *         1 if it wasn't inserted (since it is obsolete)
+ *         < 0 an if error occured
+ */
+int jffs2_add_older_frag_to_fragtree(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
+				     struct jffs2_tmp_dnode_info *tn)
+{
+	struct jffs2_node_frag *this, *newfrag;
+	uint32_t lastend;
+	struct jffs2_full_dnode *fn = tn->fn;
+	struct rb_root *root = &f->fragtree;
+	uint32_t fn_size = fn->size, fn_ofs = fn->ofs;
+	int err, checked = 0;
+	int ref_flag;
+
+	JFFS2_DBG_FRAGTREE("insert fragment %#04x-%#04x\n", fn_ofs, fn_ofs + fn_size);
+
+	/* Skip all the nodes which are completed before this one starts */
+	this = jffs2_lookup_node_frag(root, fn_ofs);
+	if (this)
+		JFFS2_DBG_FRAGTREE2("'this' found %#04x-%#04x (%s)\n", this->ofs, this->ofs + this->size, this->node ? "data" : "hole");
+
+	if (this)
+		lastend = this->ofs + this->size;
+	else
+		lastend = 0;
+	
+	/* Detect the preliminary type of node */
+	if (fn->size >= PAGE_CACHE_SIZE)
+		ref_flag = REF_PRISTINE;
+	else
+		ref_flag = REF_NORMAL;
+	
+	/* See if we ran off the end of the root */
+	if (lastend <= fn_ofs) {
+		/* We did */
+		
+		/* 
+		 * We are going to insert the new node into the
+		 * fragment tree, so check it.
+		 */
+		err = check_node(c, f, tn);
+		if (err != 0)
+			return err;
+
+		fn->frags = 1;
+
+		newfrag = new_fragment(fn, fn_ofs, fn_size);
+		if (unlikely(!newfrag))
+			return -ENOMEM;
+
+		err = no_overlapping_node(c, root, newfrag, this, lastend);
+		if (unlikely(err != 0)) {
+			jffs2_free_node_frag(newfrag);
+			return err;
+		}
+
+		goto out_ok;
+	}
+
+	fn->frags = 0;
+
+	while (1) {
+		/* 
+		 * Here we have:
+		 * fn_ofs < this->ofs + this->size && fn_ofs >= this->ofs.
+		 * 
+		 * Remember, 'this' has higher version, any non-hole node
+		 * which is already in the fragtree is newer then the newly
+		 * inserted.
+		 */
+		if (!this->node) {
+			/* 
+			 * 'this' is the hole fragment, so at least the
+			 * beginning of the new fragment is valid.
+			 */
+			
+			/* 
+			 * We are going to insert the new node into the
+			 * fragment tree, so check it.
+			 */
+			if (!checked) {
+				err = check_node(c, f, tn);
+				if (unlikely(err != 0))
+					return err;
+				checked = 1;
+			}
+			
+			if (this->ofs + this->size >= fn_ofs + fn_size) {
+				/* We split the hole on two parts */
+
+				fn->frags += 1;
+				newfrag = new_fragment(fn, fn_ofs, fn_size);
+				if (unlikely(!newfrag))
+					return -ENOMEM;
+
+				err = split_hole(c, root, newfrag, this);
+				if (unlikely(err))
+					return err;
+				goto out_ok;
+			}
+
+			/* 
+			 * The beginning of the new fragment is valid since it
+			 * overlaps the hole node.
+			 */
+
+			ref_flag = REF_NORMAL;
+
+			fn->frags += 1;
+			newfrag = new_fragment(fn, fn_ofs,
+					this->ofs + this->size - fn_ofs);
+			if (unlikely(!newfrag))
+				return -ENOMEM;
+			
+			if (fn_ofs == this->ofs) {
+				/* 
+				 * The new node starts at the same offset as
+				 * the hole and supersieds the hole.
+				 */
+				JFFS2_DBG_FRAGTREE2("add the new fragment instead of hole %#04x-%#04x, refcnt %d\n",
+					fn_ofs, fn_ofs + this->ofs + this->size - fn_ofs, fn->frags);
+
+				rb_replace_node(&this->rb, &newfrag->rb, root);
+				jffs2_free_node_frag(this);
+			} else {
+				/* 
+				 * The hole becomes shorter as its right part
+				 * is supersieded by the new fragment.
+				 */
+				JFFS2_DBG_FRAGTREE2("reduce size of hole %#04x-%#04x to %#04x-%#04x\n",
+					this->ofs, this->ofs + this->size, this->ofs, this->ofs + this->size - newfrag->size);
+				
+				JFFS2_DBG_FRAGTREE2("add new fragment %#04x-%#04x, refcnt %d\n", fn_ofs,
+					fn_ofs + this->ofs + this->size - fn_ofs, fn->frags);
+	
+				this->size -= newfrag->size;
+				jffs2_fragtree_insert(newfrag, this);
+				rb_insert_color(&newfrag->rb, root);
+			}
+			
+			fn_ofs += newfrag->size;
+			fn_size -= newfrag->size;
+			this = rb_entry(rb_next(&newfrag->rb),
+					struct jffs2_node_frag, rb);
+
+			JFFS2_DBG_FRAGTREE2("switch to the next 'this' fragment: %#04x-%#04x %s\n",
+				this->ofs, this->ofs + this->size, this->node ? "(data)" : "(hole)");
+		}
+
+		/* 
+		 * 'This' node is not the hole so it obsoletes the new fragment
+		 * either fully or partially.
+		 */
+		if (this->ofs + this->size >= fn_ofs + fn_size) {
+			/* The new node is obsolete, drop it */
+			if (fn->frags == 0) {
+				JFFS2_DBG_FRAGTREE2("%#04x-%#04x is obsolete, mark it obsolete\n", fn_ofs, fn_ofs + fn_size);
+				ref_flag = REF_OBSOLETE;
+			}
+			goto out_ok;
+		} else {
+			struct jffs2_node_frag *new_this;
+			
+			/* 'This' node obsoletes the beginning of the new node */
+			JFFS2_DBG_FRAGTREE2("the beginning %#04x-%#04x is obsolete\n", fn_ofs, this->ofs + this->size);
+
+			ref_flag = REF_NORMAL;
+			
+			fn_size -= this->ofs + this->size - fn_ofs;
+			fn_ofs = this->ofs + this->size;
+			JFFS2_DBG_FRAGTREE2("now considering %#04x-%#04x\n", fn_ofs, fn_ofs + fn_size);
+			
+			new_this = rb_entry(rb_next(&this->rb), struct jffs2_node_frag, rb);
+			if (!new_this) {
+				/* 
+				 * There is no next fragment. Add the rest of
+				 * the new node as the right-hand child.
+				 */
+				if (!checked) {
+					err = check_node(c, f, tn);
+					if (unlikely(err != 0))
+						return err;
+					checked = 1;
+				}
+				
+				fn->frags += 1;
+				newfrag = new_fragment(fn, fn_ofs, fn_size);
+				if (unlikely(!newfrag))
+					return -ENOMEM;
+
+				JFFS2_DBG_FRAGTREE2("there are no more fragments, insert %#04x-%#04x\n",
+					newfrag->ofs, newfrag->ofs + newfrag->size);
+				rb_link_node(&newfrag->rb, &this->rb, &this->rb.rb_right);			
+				rb_insert_color(&newfrag->rb, root);
+				goto out_ok;
+			} else {
+				this = new_this;
+				JFFS2_DBG_FRAGTREE2("switch to the next 'this' fragment: %#04x-%#04x %s\n",
+					this->ofs, this->ofs + this->size, this->node ? "(data)" : "(hole)");
+			}
+		}
+	}
+
+out_ok:
+	BUG_ON(fn->size < PAGE_CACHE_SIZE && ref_flag == REF_PRISTINE);
+
+	if (ref_flag == REF_OBSOLETE) {
+		JFFS2_DBG_FRAGTREE2("the node is obsolete now\n");
+		/* jffs2_mark_node_obsolete() will adjust space accounting */
+		jffs2_mark_node_obsolete(c, fn->raw);
+		return 1;
+	}
+
+	JFFS2_DBG_FRAGTREE2("the node is \"%s\" now\n", ref_flag == REF_NORMAL ? "REF_NORMAL" : "REF_PRISTINE");
+
+	/* Space accounting was adjusted at check_node_data() */
+	spin_lock(&c->erase_completion_lock);
+	fn->raw->flash_offset = ref_offset(fn->raw) | ref_flag;
+	spin_unlock(&c->erase_completion_lock);
+
+	return 0;
+}
 
 void jffs2_set_inocache_state(struct jffs2_sb_info *c, struct jffs2_inode_cache *ic, int state)
 {