[JFFS2] Finally eliminate __totlen field from struct jffs2_raw_node_ref

Well, almost. We'll actually keep a 'TEST_TOTLEN' macro set for now, and keep
doing some paranoia checks to make sure it's all working correctly. But if
TEST_TOTLEN is unset, the size of struct jffs2_raw_node_ref drops from 16
bytes to 12 on 32-bit machines. That's a saving of about half a megabyte of
memory on the OLPC prototype board, with 125K or so nodes in its 512MiB of
flash.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

diff --git a/fs/jffs2/nodelist.c b/fs/jffs2/nodelist.c
index 0050685..9a6ced0 100644 (file)
--- a/fs/jffs2/nodelist.c
+++ b/fs/jffs2/nodelist.c
@@ -1052,8 +1052,17 @@ void jffs2_link_node_ref(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
 {
        if (!jeb->first_node)
                jeb->first_node = ref;
-       if (jeb->last_node)
+       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
+       }
        jeb->last_node = ref;
 
        switch(ref_flags(ref)) {
@@ -1076,18 +1085,110 @@ void jffs2_link_node_ref(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
        c->free_size -= len;
        jeb->free_size -= len;
 
-       /* Set __totlen field... for now */
-       ref->__totlen = len;
        ref->next_phys = NULL;
+#ifdef TEST_TOTLEN
+       /* Set (and test) __totlen field... for now */
+       ref->__totlen = len;
+       ref_totlen(c, jeb, ref);
+#endif
 }
 
+/* No locking. Do not use on a live file system */
 int jffs2_scan_dirty_space(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
                           uint32_t size)
 {
-       c->dirty_size += size;
-       c->free_size -= size;
-       jeb->dirty_size += size;
-       jeb->free_size -= size;
+       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);
+               BUG();
+       }
+       if (jeb->last_node && ref_obsolete(jeb->last_node)) {
+#ifdef TEST_TOTLEN
+               jeb->last_node->__totlen += size;
+#endif
+               c->dirty_size += size;
+               c->free_size -= size;
+               jeb->dirty_size += size;
+               jeb->free_size -= size;
+       } else {
+               struct jffs2_raw_node_ref *ref;
+               ref = jffs2_alloc_raw_node_ref();
+               if (!ref)
+                       return -ENOMEM;
+
+               ref->flash_offset = jeb->offset + c->sector_size - jeb->free_size;
+               ref->flash_offset |= REF_OBSOLETE;
+               ref->next_in_ino = 0;
+#ifdef TEST_TOTLEN
+               ref->__totlen = size;
+#endif
+
+               jffs2_link_node_ref(c, jeb, ref, size);
+       }
 
        return 0;
 }
+
+/* Calculate totlen from surrounding nodes or eraseblock */
+static inline uint32_t __ref_totlen(struct jffs2_sb_info *c,
+                                   struct jffs2_eraseblock *jeb,
+                                   struct jffs2_raw_node_ref *ref)
+{
+       uint32_t ref_end;
+
+       if (ref->next_phys)
+               ref_end = ref_offset(ref->next_phys);
+       else {
+               if (!jeb)
+                       jeb = &c->blocks[ref->flash_offset / c->sector_size];
+
+               /* Last node in block. Use free_space */
+               if (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();
+               }
+               ref_end = jeb->offset + c->sector_size - jeb->free_size;
+       }
+       return ref_end - ref_offset(ref);
+}
+
+uint32_t __jffs2_ref_totlen(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
+                           struct jffs2_raw_node_ref *ref)
+{
+       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) {
+               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);
+               if (ref->next_phys) {
+                       printk(KERN_CRIT "next_phys %p (0x%08x-0x%08x)\n", ref->next_phys, ref_offset(ref->next_phys),
+                              ref_offset(ref->next_phys)+ref->__totlen);
+               } else 
+                       printk(KERN_CRIT "No next_phys. 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);
+       }
+#endif /* TEST_TOTLEN */
+       return ret;
+}

diff --git a/fs/jffs2/nodelist.h b/fs/jffs2/nodelist.h
index 94ef887..80d1fda 100644 (file)
--- a/fs/jffs2/nodelist.h
+++ b/fs/jffs2/nodelist.h
@@ -82,7 +82,10 @@ struct jffs2_raw_node_ref
                word so you know when you've got there :) */
        struct jffs2_raw_node_ref *next_phys;
        uint32_t flash_offset;
+#define TEST_TOTLEN
+#ifdef TEST_TOTLEN
        uint32_t __totlen; /* This may die; use ref_totlen(c, jeb, ) below */
+#endif
 };
 
         /* flash_offset & 3 always has to be zero, because nodes are
@@ -221,57 +224,7 @@ static inline int jffs2_blocks_use_vmalloc(struct jffs2_sb_info *c)
        return ((c->flash_size / c->sector_size) * sizeof (struct jffs2_eraseblock)) > (128 * 1024);
 }
 
-/* Calculate totlen from surrounding nodes or eraseblock */
-static inline uint32_t __ref_totlen(struct jffs2_sb_info *c,
-                                   struct jffs2_eraseblock *jeb,
-                                   struct jffs2_raw_node_ref *ref)
-{
-       uint32_t ref_end;
-
-       if (ref->next_phys)
-               ref_end = ref_offset(ref->next_phys);
-       else {
-               if (!jeb)
-                       jeb = &c->blocks[ref->flash_offset / c->sector_size];
-
-               /* Last node in block. Use free_space */
-               BUG_ON(ref != jeb->last_node);
-               ref_end = jeb->offset + c->sector_size - jeb->free_size;
-       }
-       return ref_end - ref_offset(ref);
-}
-
-static inline uint32_t ref_totlen(struct jffs2_sb_info *c,
-                                 struct jffs2_eraseblock *jeb,
-                                 struct jffs2_raw_node_ref *ref)
-{
-       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
-
-#if 1
-       ret = ref->__totlen;
-#else
-       /* This doesn't actually work yet */
-       ret = __ref_totlen(c, jeb, ref);
-       if (ret != ref->__totlen) {
-               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);
-               if (!jeb)
-                       jeb = &c->blocks[ref->flash_offset / c->sector_size];
-               jffs2_dbg_dump_node_refs_nolock(c, jeb);
-               BUG();
-       }
-#endif
-       return ret;
-}
+#define ref_totlen(a, b, c) __jffs2_ref_totlen((a), (b), (c))
 
 #define ALLOC_NORMAL   0       /* Normal allocation */
 #define ALLOC_DELETION 1       /* Deletion node. Best to allow it */
@@ -355,6 +308,9 @@ void jffs2_truncate_fragtree (struct jffs2_sb_info *c, struct rb_root *list, uin
 int jffs2_add_older_frag_to_fragtree(struct jffs2_sb_info *c, struct jffs2_inode_info *f, struct jffs2_tmp_dnode_info *tn);
 void jffs2_link_node_ref(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
                         struct jffs2_raw_node_ref *ref, uint32_t len);
+extern uint32_t __jffs2_ref_totlen(struct jffs2_sb_info *c,
+                                  struct jffs2_eraseblock *jeb,
+                                  struct jffs2_raw_node_ref *ref);
 
 /* nodemgmt.c */
 int jffs2_thread_should_wake(struct jffs2_sb_info *c);

diff --git a/fs/jffs2/nodemgmt.c b/fs/jffs2/nodemgmt.c
index 4701556..9a0f312 100644 (file)
--- a/fs/jffs2/nodemgmt.c
+++ b/fs/jffs2/nodemgmt.c
@@ -386,7 +386,9 @@ int jffs2_add_physical_node_ref(struct jffs2_sb_info *c, struct jffs2_raw_node_r
        struct jffs2_eraseblock *jeb;
 
        jeb = &c->blocks[new->flash_offset / c->sector_size];
+#ifdef TEST_TOTLEN
        new->__totlen = len;
+#endif
 
        D1(printk(KERN_DEBUG "jffs2_add_physical_node_ref(): Node at 0x%x(%d), size 0x%x\n", ref_offset(new), ref_flags(new), len));
 #if 1
@@ -679,7 +681,9 @@ void jffs2_mark_node_obsolete(struct jffs2_sb_info *c, struct jffs2_raw_node_ref
 
                spin_lock(&c->erase_completion_lock);
 
+#ifdef TEST_TOTLEN
                ref->__totlen += n->__totlen;
+#endif
                ref->next_phys = n->next_phys;
                 if (jeb->last_node == n) jeb->last_node = ref;
                if (jeb->gc_node == n) {
@@ -702,7 +706,9 @@ void jffs2_mark_node_obsolete(struct jffs2_sb_info *c, struct jffs2_raw_node_ref
                        p = p->next_phys;
 
                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;
                        }