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authorKent Overstreet <kmo@daterainc.com>2013-07-25 04:20:19 +0400
committerKent Overstreet <kmo@daterainc.com>2013-11-11 09:55:57 +0400
commitd6fd3b11cea82346837957feab25b0be48aa424c (patch)
tree992f1de98ba935284feac7569eea7d86dcf5bdd7 /drivers/md/bcache
parent8304ad4dc818ffd701c2f3e90683b5b8013f44e2 (diff)
downloadlinux-d6fd3b11cea82346837957feab25b0be48aa424c.tar.xz
bcache: Explicitly track btree node's parent
This is prep work for the reworked btree insertion code. The way we set b->parent is ugly and hacky... the problem is, when btree_split() or garbage collection splits or rewrites a btree node, the parent changes for all its (potentially already cached) children. I may change this later and add some code to look through the btree node cache and find all our cached child nodes and change the parent pointer then... Signed-off-by: Kent Overstreet <kmo@daterainc.com>
Diffstat (limited to 'drivers/md/bcache')
-rw-r--r--drivers/md/bcache/btree.c14
-rw-r--r--drivers/md/bcache/btree.h16
2 files changed, 20 insertions, 10 deletions
diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
index d1734d9d9c79..87299baa8a1b 100644
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -884,6 +884,7 @@ out:
lock_set_subclass(&b->lock.dep_map, level + 1, _THIS_IP_);
b->level = level;
+ b->parent = (void *) ~0UL;
mca_reinit(b);
@@ -1898,7 +1899,7 @@ out:
static int btree_split(struct btree *b, struct btree_op *op)
{
- bool split, root = b == b->c->root;
+ bool split;
struct btree *n1, *n2 = NULL, *n3 = NULL;
uint64_t start_time = local_clock();
@@ -1920,7 +1921,7 @@ static int btree_split(struct btree *b, struct btree_op *op)
if (IS_ERR(n2))
goto err_free1;
- if (root) {
+ if (!b->parent) {
n3 = bch_btree_node_alloc(b->c, b->level + 1, &op->cl);
if (IS_ERR(n3))
goto err_free2;
@@ -1928,7 +1929,8 @@ static int btree_split(struct btree *b, struct btree_op *op)
bch_btree_insert_keys(n1, op);
- /* Has to be a linear search because we don't have an auxiliary
+ /*
+ * Has to be a linear search because we don't have an auxiliary
* search tree yet
*/
@@ -1960,6 +1962,8 @@ static int btree_split(struct btree *b, struct btree_op *op)
bch_btree_node_write(n1, &op->cl);
if (n3) {
+ /* Depth increases, make a new root */
+
bkey_copy_key(&n3->key, &MAX_KEY);
bch_btree_insert_keys(n3, op);
bch_btree_node_write(n3, &op->cl);
@@ -1967,7 +1971,9 @@ static int btree_split(struct btree *b, struct btree_op *op)
closure_sync(&op->cl);
bch_btree_set_root(n3);
rw_unlock(true, n3);
- } else if (root) {
+ } else if (!b->parent) {
+ /* Root filled up but didn't need to be split */
+
op->keys.top = op->keys.bottom;
closure_sync(&op->cl);
bch_btree_set_root(n1);
diff --git a/drivers/md/bcache/btree.h b/drivers/md/bcache/btree.h
index 8a1c7e6bbbe3..6d2fb7550706 100644
--- a/drivers/md/bcache/btree.h
+++ b/drivers/md/bcache/btree.h
@@ -125,6 +125,7 @@ struct btree {
unsigned long seq;
struct rw_semaphore lock;
struct cache_set *c;
+ struct btree *parent;
unsigned long flags;
uint16_t written; /* would be nice to kill */
@@ -327,12 +328,13 @@ static inline void rw_unlock(bool w, struct btree *b)
({ \
int _r, l = (b)->level - 1; \
bool _w = l <= (op)->lock; \
- struct btree *_b = bch_btree_node_get((b)->c, key, l, op); \
- if (!IS_ERR(_b)) { \
- _r = bch_btree_ ## fn(_b, op, ##__VA_ARGS__); \
- rw_unlock(_w, _b); \
+ struct btree *_child = bch_btree_node_get((b)->c, key, l, op); \
+ if (!IS_ERR(_child)) { \
+ _child->parent = (b); \
+ _r = bch_btree_ ## fn(_child, op, ##__VA_ARGS__); \
+ rw_unlock(_w, _child); \
} else \
- _r = PTR_ERR(_b); \
+ _r = PTR_ERR(_child); \
_r; \
})
@@ -350,8 +352,10 @@ static inline void rw_unlock(bool w, struct btree *b)
bool _w = insert_lock(op, _b); \
rw_lock(_w, _b, _b->level); \
if (_b == (c)->root && \
- _w == insert_lock(op, _b)) \
+ _w == insert_lock(op, _b)) { \
+ _b->parent = NULL; \
_r = bch_btree_ ## fn(_b, op, ##__VA_ARGS__); \
+ } \
rw_unlock(_w, _b); \
bch_cannibalize_unlock(c, &(op)->cl); \
} while (_r == -EINTR); \