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Fix item cache val_len alignment math

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Some item_val_len() callers were applying alignment twice, which isn't
needed.

And additions to erased_bytes as value lengths change  didn't take
alignment into account.  They could end up double counting if val_len
changes within the alignment are then accounted for again as the full
item and alignment is later deleted.  Additions to erased_bytes based on
val_len should always take alignment into account.

Signed-off-by: Zach Brown <zab@versity.com>
This commit is contained in:
Zach Brown
2021-06-17 09:36:00 -07:00
parent c5c050bef0
commit d67db6662b
1 changed files with 8 additions and 7 deletions
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kmod/src/item.c
+8 -7
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@@ -149,7 +149,8 @@ struct cached_item {
static int item_val_bytes(int val_len)
{
return round_up(offsetof(struct cached_item, val[val_len]), CACHED_ITEM_ALIGN);
return round_up(offsetof(struct cached_item, val[val_len]),
CACHED_ITEM_ALIGN);
}
/*
@@ -421,8 +422,7 @@ static struct cached_item *alloc_item(struct cached_page *pg,
static void erase_item(struct cached_page *pg, struct cached_item *item)
{
rbtree_erase(&item->node, &pg->item_root);
pg->erased_bytes += round_up(item_val_bytes(item->val_len),
CACHED_ITEM_ALIGN);
pg->erased_bytes += item_val_bytes(item->val_len);
}
static void lru_add(struct super_block *sb, struct item_cache_info *cinf,
@@ -853,8 +853,7 @@ static void compact_page_items(struct super_block *sb,
for (from = first_item(&pg->item_root); from; from = next_item(from)) {
to = page_address(empty->page) + page_off;
page_off += round_up(item_val_bytes(from->val_len),
CACHED_ITEM_ALIGN);
page_off += item_val_bytes(from->val_len);
/* copy the entire item, struct members and all */
memcpy(to, from, item_val_bytes(from->val_len));
@@ -1960,7 +1959,8 @@ int scoutfs_item_update(struct super_block *sb, struct scoutfs_key *key,
if (val_len)
memcpy(found->val, val, val_len);
if (val_len < found->val_len)
pg->erased_bytes += found->val_len - val_len;
pg->erased_bytes += item_val_bytes(found->val_len) -
item_val_bytes(val_len);
found->val_len = val_len;
found->liv.seq = liv.seq;
mark_item_dirty(sb, cinf, pg, NULL, found);
@@ -2039,7 +2039,8 @@ static int item_delete(struct super_block *sb, struct scoutfs_key *key,
item->liv.seq = liv.seq;
item->liv.flags |= SCOUTFS_LOG_ITEM_FLAG_DELETION;
item->deletion = 1;
pg->erased_bytes += item->val_len;
pg->erased_bytes += item_val_bytes(item->val_len) -
item_val_bytes(0);
item->val_len = 0;
mark_item_dirty(sb, cinf, pg, NULL, item);
}