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scoutfs: add scoutfs_item_range_cached()

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Add a quick helper for querying if a given range of keys is covered by
the item cache.

Signed-off-by: Zach Brown <zab@versity.com>
This commit is contained in:
Zach Brown
2018-03-08 15:19:07 -08:00
committed by Zach Brown
parent 951b6d8dcd
commit 2aa613dae5
2 changed files with 54 additions and 9 deletions
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60
kmod/src/item.c
View File

@@ -1683,6 +1683,19 @@ static struct cached_item *next_dirty(struct cached_item *item)
return NULL;
}
static bool dirty_item_within(struct rb_root *root,
struct scoutfs_key_buf *from,
struct scoutfs_key_buf *end)
{
struct cached_item *item;
item = next_item(root, from);
if (item && !(item->dirty & ITEM_DIRTY))
item = next_dirty(item);
return item && scoutfs_key_compare(item->key, end) <= 0;
}
bool scoutfs_item_has_dirty(struct super_block *sb)
{
struct scoutfs_sb_info *sbi = SCOUTFS_SB(sb);
@@ -1697,6 +1710,41 @@ bool scoutfs_item_has_dirty(struct super_block *sb)
return has;
}
/*
* Return true if the item cache covers the given range. If dirty is
* provided then we only return true if there are dirty items in the
* range.
*
* If the start of the query range doesn't overlap a cached range then
* we see if the next cached range starts before the end of the query range.
*/
bool scoutfs_item_range_cached(struct super_block *sb,
struct scoutfs_key_buf *start,
struct scoutfs_key_buf *end, bool dirty)
{
struct scoutfs_sb_info *sbi = SCOUTFS_SB(sb);
struct item_cache *cac = sbi->item_cache;
struct cached_range *next;
struct cached_range *rng;
unsigned long flags;
bool cached = false;
spin_lock_irqsave(&cac->lock, flags);
if (dirty) {
if (dirty_item_within(&cac->items, start, end))
cached = true;
} else {
rng = walk_ranges(&cac->ranges, start, NULL, &next);
if (rng || (next && scoutfs_key_compare(next->start, end) <= 0))
cached = true;
}
spin_unlock_irqrestore(&cac->lock, flags);
return cached;
}
/*
* Returns true if adding more items with the given count, keys, and values
* still fits in a single item along with the current dirty items.
@@ -1774,7 +1822,6 @@ int scoutfs_item_writeback(struct super_block *sb,
{
struct scoutfs_sb_info *sbi = SCOUTFS_SB(sb);
struct item_cache *cac = sbi->item_cache;
struct cached_item *item;
unsigned long flags;
bool sync = false;
int count = 0;
@@ -1784,14 +1831,9 @@ int scoutfs_item_writeback(struct super_block *sb,
spin_lock_irqsave(&cac->lock, flags);
if (cac->nr_dirty_items) {
item = next_item(&cac->items, start);
if (item && !(item->dirty & ITEM_DIRTY))
item = next_dirty(item);
if (item && scoutfs_key_compare(item->key, end) <= 0) {
sync = true;
count = cac->nr_dirty_items;
}
if (cac->nr_dirty_items && dirty_item_within(&cac->items, start, end)) {
sync = true;
count = cac->nr_dirty_items;
}
spin_unlock_irqrestore(&cac->lock, flags);

3
kmod/src/item.h
View File

@@ -59,6 +59,9 @@ int scoutfs_item_set_batch(struct super_block *sb, struct list_head *list,
void scoutfs_item_free_batch(struct super_block *sb, struct list_head *list);
bool scoutfs_item_has_dirty(struct super_block *sb);
bool scoutfs_item_range_cached(struct super_block *sb,
struct scoutfs_key_buf *start,
struct scoutfs_key_buf *end, bool dirty);
bool scoutfs_item_dirty_fits_single(struct super_block *sb, u32 nr_items,
u32 key_bytes, u32 val_bytes);
int scoutfs_item_dirty_seg(struct super_block *sb, struct scoutfs_segment *seg);