[JFFS2] Switch to using an array of jffs2_raw_node_refs instead of a list.

This allows us to drop another pointer from the struct jffs2_raw_node_ref,
shrinking it to 8 bytes on 32-bit machines (if the TEST_TOTLEN) paranoia
check is turned off, which will be committed soon).
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

fs/jffs2/erase.c

@@ -285,20 +285,25 @@ static inline void jffs2_remove_node_refs_from_ino_list(struct jffs2_sb_info *c,
 
 void jffs2_free_jeb_node_refs(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
 {
-	struct jffs2_raw_node_ref *ref;
+	struct jffs2_raw_node_ref *block, *ref;
 	D1(printk(KERN_DEBUG "Freeing all node refs for eraseblock offset 0x%08x\n", jeb->offset));
-	while(jeb->first_node) {
-		ref = jeb->first_node;
-		jeb->first_node = ref->next_phys;
 
-		/* Remove from the inode-list */
-		if (ref->next_in_ino)
+	block = ref = jeb->first_node;
+
+	while (ref) {
+		if (ref->flash_offset == REF_LINK_NODE) {
+			ref = ref->next_in_ino;
+			jffs2_free_refblock(block);
+			block = ref;
+			continue;
+		}
+		if (ref->flash_offset != REF_EMPTY_NODE && ref->next_in_ino)
 			jffs2_remove_node_refs_from_ino_list(c, ref, jeb);
 		/* else it was a non-inode node or already removed, so don't bother */
 
-		__jffs2_free_raw_node_ref(ref);
+		ref++;
 	}
-	jeb->last_node = NULL;
+	jeb->first_node = jeb->last_node = NULL;
 }
 
 static int jffs2_block_check_erase(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, uint32_t *bad_offset)

fs/jffs2/jffs2_fs_sb.h

@@ -26,9 +26,6 @@ struct jffs2_inodirty;
 struct jffs2_sb_info {
 	struct mtd_info *mtd;
 
-	struct jffs2_raw_node_ref *refs;
-	int reserved_refs;
-
 	uint32_t highest_ino;
 	uint32_t checked_ino;
 

fs/jffs2/malloc.c

@@ -57,8 +57,8 @@ int __init jffs2_create_slab_caches(void)
 	if (!tmp_dnode_info_slab)
 		goto err;
 
-	raw_node_ref_slab = kmem_cache_create("jffs2_raw_node_ref",
-					      sizeof(struct jffs2_raw_node_ref),
+	raw_node_ref_slab = kmem_cache_create("jffs2_refblock",
+					      sizeof(struct jffs2_raw_node_ref) * (REFS_PER_BLOCK + 1),
 					      0, 0, NULL, NULL);
 	if (!raw_node_ref_slab)
 		goto err;
@@ -190,38 +190,65 @@ void jffs2_free_tmp_dnode_info(struct jffs2_tmp_dnode_info *x)
 	kmem_cache_free(tmp_dnode_info_slab, x);
 }
 
+struct jffs2_raw_node_ref *jffs2_alloc_refblock(void)
+{
+	struct jffs2_raw_node_ref *ret;
+
+	ret = kmem_cache_alloc(raw_node_ref_slab, GFP_KERNEL);
+	if (ret) {
+		int i = 0;
+		for (i=0; i < REFS_PER_BLOCK; i++) {
+			ret[i].flash_offset = REF_EMPTY_NODE;
+			ret[i].next_in_ino = NULL;
+		}
+		ret[i].flash_offset = REF_LINK_NODE;
+		ret[i].next_in_ino = NULL;
+	}
+	return ret;
+}
+
 int jffs2_prealloc_raw_node_refs(struct jffs2_sb_info *c,
 				 struct jffs2_eraseblock *jeb, int nr)
 {
-	struct jffs2_raw_node_ref *p = c->refs;
+	struct jffs2_raw_node_ref **p, *ref;
+	int i = nr;
 
 	dbg_memalloc("%d\n", nr);
 
-	while (nr && p) {
-		p = p->next_in_ino;
-		nr--;
-	}
-	while (nr) {
-		p = __jffs2_alloc_raw_node_ref();
-		if (!p)
-			return -ENOMEM;
-		p->next_in_ino = c->refs;
-		c->refs = p;
-		nr--;
+	p = &jeb->last_node;
+	ref = *p;
+
+	dbg_memalloc("Reserving %d refs for block @0x%08x\n", nr, jeb->offset);
+
+	/* If jeb->last_node is really a valid node then skip over it */
+	if (ref && ref->flash_offset != REF_EMPTY_NODE)
+		ref++;
+
+	while (i) {
+		if (!ref) {
+			dbg_memalloc("Allocating new refblock linked from %p\n", p);
+			ref = *p = jffs2_alloc_refblock();
+			if (!ref)
+				return -ENOMEM;
+		}
+		if (ref->flash_offset == REF_LINK_NODE) {
+			p = &ref->next_in_ino;
+			ref = *p;
+			continue;
+		}
+		i--;
+		ref++;
 	}
-	c->reserved_refs = nr;
-	return 0;
-}
+	jeb->allocated_refs = nr;
 
-struct jffs2_raw_node_ref *__jffs2_alloc_raw_node_ref(void)
-{
-	struct jffs2_raw_node_ref *ret;
-	ret = kmem_cache_alloc(raw_node_ref_slab, GFP_KERNEL);
-	dbg_memalloc("%p\n", ret);
-	return ret;
+	dbg_memalloc("Reserved %d refs for block @0x%08x, last_node is %p (%08x,%p)\n",
+		  nr, jeb->offset, jeb->last_node, jeb->last_node->flash_offset,
+		  jeb->last_node->next_in_ino);
+
+	return 0;
 }
 
-void __jffs2_free_raw_node_ref(struct jffs2_raw_node_ref *x)
+void jffs2_free_refblock(struct jffs2_raw_node_ref *x)
 {
 	dbg_memalloc("%p\n", x);
 	kmem_cache_free(raw_node_ref_slab, x);

fs/jffs2/nodelist.c

@@ -954,18 +954,16 @@ void jffs2_free_raw_node_refs(struct jffs2_sb_info *c)
 	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);
+			if (this[REFS_PER_BLOCK].flash_offset == REF_LINK_NODE)
+				next = this[REFS_PER_BLOCK].next_in_ino;
+			else
+				next = NULL;
+
+			jffs2_free_refblock(this);
 			this = next;
 		}
 		c->blocks[i].first_node = c->blocks[i].last_node = NULL;
 	}
-	this = c->refs;
-	while (this) {
-		next = this->next_in_ino;
-		__jffs2_free_raw_node_ref(this);
-		this = next;
-	}
 }
 
 struct jffs2_node_frag *jffs2_lookup_node_frag(struct rb_root *fragtree, uint32_t offset)
@@ -1060,32 +1058,37 @@ struct jffs2_raw_node_ref *jffs2_link_node_ref(struct jffs2_sb_info *c,
 {
 	struct jffs2_raw_node_ref *ref;
 
-	/* These will be preallocated _very_ shortly. */
-	ref = c->refs;
-	if (!c->refs) {
-		JFFS2_WARNING("Using non-preallocated refs!\n");
-		ref = __jffs2_alloc_raw_node_ref();
-		BUG_ON(!ref);
-		WARN_ON(1);
-	} else {
-		c->refs = ref->next_in_ino;
+	BUG_ON(!jeb->allocated_refs);
+	jeb->allocated_refs--;
+
+	ref = jeb->last_node;
+
+	dbg_noderef("Last node at %p is (%08x,%p)\n", ref, ref->flash_offset,
+		    ref->next_in_ino);
+
+	while (ref->flash_offset != REF_EMPTY_NODE) {
+		if (ref->flash_offset == REF_LINK_NODE)
+			ref = ref->next_in_ino;
+		else
+			ref++;
 	}
 
-	ref->next_phys = NULL;
+	dbg_noderef("New ref is %p (%08x becomes %08x,%p) len 0x%x\n", ref, 
+		    ref->flash_offset, ofs, ref->next_in_ino, len);
+
 	ref->flash_offset = ofs;
 
-	if (!jeb->first_node)
+	if (!jeb->first_node) {
 		jeb->first_node = ref;
-	if (jeb->last_node) {
-		jeb->last_node->next_phys = ref;
-#ifdef TEST_TOTLEN
-		if (ref_offset(jeb->last_node) + jeb->last_node->__totlen != ref_offset(ref)) {
-			printk(KERN_CRIT "Adding new ref %p at (0x%08x-0x%08x) not immediately after previous (0x%08x-0x%08x)\n",
-			       ref, ref_offset(ref), ref_offset(ref)+ref->__totlen,
-			       ref_offset(jeb->last_node), ref_offset(jeb->last_node)+jeb->last_node->__totlen);
-			WARN_ON(1);
-		}
-#endif
+		BUG_ON(ref_offset(ref) != jeb->offset);
+	} else if (unlikely(ref_offset(ref) != jeb->offset + c->sector_size - jeb->free_size)) {
+		uint32_t last_len = ref_totlen(c, jeb, jeb->last_node);
+
+		JFFS2_ERROR("Adding new ref %p at (0x%08x-0x%08x) not immediately after previous (0x%08x-0x%08x)\n",
+			    ref, ref_offset(ref), ref_offset(ref)+len,
+			    ref_offset(jeb->last_node), 
+			    ref_offset(jeb->last_node)+last_len);
+		BUG();
 	}
 	jeb->last_node = ref;
 
@@ -1130,12 +1133,13 @@ int jffs2_scan_dirty_space(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb
 {
 	if (!size)
 		return 0;
-	if (size > c->sector_size - jeb->used_size) {
-		printk(KERN_CRIT "Dirty space 0x%x larger then used_size 0x%x (wasted 0x%x)\n",
-		       size, jeb->used_size, jeb->wasted_size);
+	if (unlikely(size > jeb->free_size)) {
+		printk(KERN_CRIT "Dirty space 0x%x larger then free_size 0x%x (wasted 0x%x)\n",
+		       size, jeb->free_size, jeb->wasted_size);
 		BUG();
 	}
-	if (jeb->last_node && ref_obsolete(jeb->last_node)) {
+	/* REF_EMPTY_NODE is !obsolete, so that works OK */
+	if (ref_obsolete(jeb->last_node)) {
 #ifdef TEST_TOTLEN
 		jeb->last_node->__totlen += size;
 #endif
@@ -1168,7 +1172,7 @@ static inline uint32_t __ref_totlen(struct jffs2_sb_info *c,
 			jeb = &c->blocks[ref->flash_offset / c->sector_size];
 
 		/* Last node in block. Use free_space */
-		if (ref != jeb->last_node) {
+		if (unlikely(ref != jeb->last_node)) {
 			printk(KERN_CRIT "ref %p @0x%08x is not jeb->last_node (%p @0x%08x)\n",
 			       ref, ref_offset(ref), jeb->last_node, jeb->last_node?ref_offset(jeb->last_node):0);
 			BUG();
@@ -1183,17 +1187,13 @@ uint32_t __jffs2_ref_totlen(struct jffs2_sb_info *c, struct jffs2_eraseblock *je
 {
 	uint32_t ret;
 
-#if CONFIG_JFFS2_FS_DEBUG > 0
-	if (jeb && jeb != &c->blocks[ref->flash_offset / c->sector_size]) {
-		printk(KERN_CRIT "ref_totlen called with wrong block -- at 0x%08x instead of 0x%08x; ref 0x%08x\n",
-		       jeb->offset, c->blocks[ref->flash_offset / c->sector_size].offset, ref_offset(ref));
-		BUG();
-	}
-#endif
-
 	ret = __ref_totlen(c, jeb, ref);
+
 #ifdef TEST_TOTLEN
-	if (ret != ref->__totlen) {
+	if (unlikely(ret != ref->__totlen)) {
+		if (!jeb)
+			jeb = &c->blocks[ref->flash_offset / c->sector_size];
+
 		printk(KERN_CRIT "Totlen for ref at %p (0x%08x-0x%08x) miscalculated as 0x%x instead of %x\n",
 		       ref, ref_offset(ref), ref_offset(ref)+ref->__totlen,
 		       ret, ref->__totlen);
@@ -1204,13 +1204,14 @@ uint32_t __jffs2_ref_totlen(struct jffs2_sb_info *c, struct jffs2_eraseblock *je
 			printk(KERN_CRIT "No next ref. jeb->last_node is %p\n", jeb->last_node);
 
 		printk(KERN_CRIT "jeb->wasted_size %x, dirty_size %x, used_size %x, free_size %x\n", jeb->wasted_size, jeb->dirty_size, jeb->used_size, jeb->free_size);
-		ret = ref->__totlen;
-		if (!jeb)
-			jeb = &c->blocks[ref->flash_offset / c->sector_size];
+
 #if defined(JFFS2_DBG_DUMPS) || defined(JFFS2_DBG_PARANOIA_CHECKS)
 		__jffs2_dbg_dump_node_refs_nolock(c, jeb);
 #endif
+
 		WARN_ON(1);
+
+		ret = ref->__totlen;
 	}
 #endif /* TEST_TOTLEN */
 	return ret;

fs/jffs2/nodelist.h

@@ -80,7 +80,6 @@ struct jffs2_raw_node_ref
 		for this object. If this _is_ the last, it points to the inode_cache,
 		xattr_ref or xattr_datum instead. The common part of those structures
 		has NULL in the first word. See jffs2_raw_ref_to_ic() below */
-	struct jffs2_raw_node_ref *next_phys;
 	uint32_t flash_offset;
 #define TEST_TOTLEN
 #ifdef TEST_TOTLEN
@@ -88,7 +87,29 @@ struct jffs2_raw_node_ref
 #endif
 };
 
-#define ref_next(r) ((r)->next_phys)
+#define REF_LINK_NODE ((int32_t)-1)
+#define REF_EMPTY_NODE ((int32_t)-2)
+
+/* Use blocks of about 256 bytes */
+#define REFS_PER_BLOCK ((255/sizeof(struct jffs2_raw_node_ref))-1)
+
+static inline struct jffs2_raw_node_ref *ref_next(struct jffs2_raw_node_ref *ref)
+{
+	ref++;
+
+	/* Link to another block of refs */
+	if (ref->flash_offset == REF_LINK_NODE) {
+		ref = ref->next_in_ino;
+		if (!ref)
+			return ref;
+	}
+
+	/* End of chain */
+	if (ref->flash_offset == REF_EMPTY_NODE)
+		return NULL;
+
+	return ref;
+}
 
 static inline struct jffs2_inode_cache *jffs2_raw_ref_to_ic(struct jffs2_raw_node_ref *raw)
 {
@@ -234,6 +255,7 @@ struct jffs2_eraseblock
 	uint32_t wasted_size;
 	uint32_t free_size;	/* Note that sector_size - free_size
 				   is the address of the first free space */
+	uint32_t allocated_refs;
 	struct jffs2_raw_node_ref *first_node;
 	struct jffs2_raw_node_ref *last_node;
 
@@ -378,10 +400,9 @@ struct jffs2_raw_inode *jffs2_alloc_raw_inode(void);
 void jffs2_free_raw_inode(struct jffs2_raw_inode *);
 struct jffs2_tmp_dnode_info *jffs2_alloc_tmp_dnode_info(void);
 void jffs2_free_tmp_dnode_info(struct jffs2_tmp_dnode_info *);
-int jffs2_prealloc_raw_node_refs(struct jffs2_sb_info *c, 
+int jffs2_prealloc_raw_node_refs(struct jffs2_sb_info *c,
 				 struct jffs2_eraseblock *jeb, int nr);
-struct jffs2_raw_node_ref *__jffs2_alloc_raw_node_ref(void);
-void __jffs2_free_raw_node_ref(struct jffs2_raw_node_ref *);
+void jffs2_free_refblock(struct jffs2_raw_node_ref *);
 struct jffs2_node_frag *jffs2_alloc_node_frag(void);
 void jffs2_free_node_frag(struct jffs2_node_frag *);
 struct jffs2_inode_cache *jffs2_alloc_inode_cache(void);

fs/jffs2/nodemgmt.c

@@ -458,14 +458,13 @@ static inline int on_list(struct list_head *obj, struct list_head *head)
 void jffs2_mark_node_obsolete(struct jffs2_sb_info *c, struct jffs2_raw_node_ref *ref)
 {
 	struct jffs2_eraseblock *jeb;
-	struct jffs2_raw_node_ref *next_ref;
 	int blocknr;
 	struct jffs2_unknown_node n;
 	int ret, addedsize;
 	size_t retlen;
 	uint32_t freed_len;
 
-	if(!ref) {
+	if(unlikely(!ref)) {
 		printk(KERN_NOTICE "EEEEEK. jffs2_mark_node_obsolete called with NULL node\n");
 		return;
 	}
@@ -683,54 +682,6 @@ void jffs2_mark_node_obsolete(struct jffs2_sb_info *c, struct jffs2_raw_node_ref
 		spin_unlock(&c->erase_completion_lock);
 	}
 
-
-	/* Merge with the next node in the physical list, if there is one
-	   and if it's also obsolete and if it doesn't belong to any inode */
-	next_ref = ref_next(ref);
-
-	if (next_ref && ref_obsolete(next_ref) && !next_ref->next_in_ino) {
-		spin_lock(&c->erase_completion_lock);
-
-#ifdef TEST_TOTLEN
-		ref->__totlen += next_ref->__totlen;
-#endif
-		ref->next_phys = ref_next(next_ref);
-                if (jeb->last_node == next_ref) jeb->last_node = ref;
-		if (jeb->gc_node == next_ref) {
-			/* gc will be happy continuing gc on this node */
-			jeb->gc_node=ref;
-		}
-		spin_unlock(&c->erase_completion_lock);
-
-		__jffs2_free_raw_node_ref(next_ref);
-	}
-
-	/* Also merge with the previous node in the list, if there is one
-	   and that one is obsolete */
-	if (ref != jeb->first_node ) {
-		struct jffs2_raw_node_ref *p = jeb->first_node;
-
-		spin_lock(&c->erase_completion_lock);
-
-		while ((next_ref = ref_next(ref)) != ref)
-			p = next_ref;
-
-		if (ref_obsolete(p) && !ref->next_in_ino) {
-#ifdef TEST_TOTLEN
-			p->__totlen += ref->__totlen;
-#endif
-			if (jeb->last_node == ref) {
-				jeb->last_node = p;
-			}
-			if (jeb->gc_node == ref) {
-				/* gc will be happy continuing gc on this node */
-				jeb->gc_node=p;
-			}
-			p->next_phys = ref_next(ref);
-			__jffs2_free_raw_node_ref(ref);
-		}
-		spin_unlock(&c->erase_completion_lock);
-	}
  out_erase_sem:
 	up(&c->erase_free_sem);
 }

fs/jffs2/os-linux.h

@@ -95,6 +95,7 @@ static inline void jffs2_init_inode_info(struct jffs2_inode_info *f)
 #define jffs2_dataflash(c) (0)
 #define jffs2_dataflash_setup(c) (0)
 #define jffs2_dataflash_cleanup(c) do {} while (0)
+#define jffs2_nor_wbuf_flash(c) (0)
 #define jffs2_nor_wbuf_flash_setup(c) (0)
 #define jffs2_nor_wbuf_flash_cleanup(c) do {} while (0)
 

fs/jffs2/summary.c

@@ -511,7 +511,8 @@ static int jffs2_sum_process_sum_data(struct jffs2_sb_info *c, struct jffs2_eras
 				spr = (struct jffs2_sum_xref_flash *)sp;
 				dbg_summary("xref at %#08x-%#08x\n",
 					    jeb->offset + je32_to_cpu(spr->offset),
-					    jeb->offset + je32_to_cpu(spr->offset) + PAD(sizeof(struct jffs2_raw_xref)));
+					    jeb->offset + je32_to_cpu(spr->offset) + 
+					    (uint32_t)PAD(sizeof(struct jffs2_raw_xref)));
 
 				ref = jffs2_alloc_xattr_ref();
 				if (!ref) {
@@ -787,10 +788,12 @@ static int jffs2_sum_write_data(struct jffs2_sb_info *c, struct jffs2_eraseblock
 		JFFS2_WARNING("Write of %u bytes at 0x%08x failed. returned %d, retlen %zd\n",
 			      infosize, sum_ofs, ret, retlen);
 
-		/* Waste remaining space */
-		spin_lock(&c->erase_completion_lock);
-		jffs2_link_node_ref(c, jeb, sum_ofs | REF_OBSOLETE, infosize, NULL);
-		spin_unlock(&c->erase_completion_lock);
+		if (retlen) {
+			/* Waste remaining space */
+			spin_lock(&c->erase_completion_lock);
+			jffs2_link_node_ref(c, jeb, sum_ofs | REF_OBSOLETE, infosize, NULL);
+			spin_unlock(&c->erase_completion_lock);
+		}
 
 		c->summary->sum_size = JFFS2_SUMMARY_NOSUM_SIZE;
 
@@ -836,6 +839,7 @@ int jffs2_sum_write_sumnode(struct jffs2_sb_info *c)
 		jffs2_sum_disable_collecting(c->summary);
 
 		JFFS2_WARNING("Not enough space for summary, padsize = %d\n", padsize);
+		spin_lock(&c->erase_completion_lock);
 		return 0;
 	}