@@ -1896,7 +1896,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
left = NULL;
if (left) {
- btrfs_tree_lock(left);
+ __btrfs_tree_lock(left, BTRFS_NESTING_LEFT);
btrfs_set_lock_blocking_write(left);
wret = btrfs_cow_block(trans, root, left,
parent, pslot - 1, &left,
@@ -1912,7 +1912,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
right = NULL;
if (right) {
- btrfs_tree_lock(right);
+ __btrfs_tree_lock(right, BTRFS_NESTING_RIGHT);
btrfs_set_lock_blocking_write(right);
wret = btrfs_cow_block(trans, root, right,
parent, pslot + 1, &right,
@@ -2076,7 +2076,7 @@ static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans,
if (left) {
u32 left_nr;
- btrfs_tree_lock(left);
+ __btrfs_tree_lock(left, BTRFS_NESTING_LEFT);
btrfs_set_lock_blocking_write(left);
left_nr = btrfs_header_nritems(left);
@@ -2131,7 +2131,7 @@ static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans,
if (right) {
u32 right_nr;
- btrfs_tree_lock(right);
+ __btrfs_tree_lock(right, BTRFS_NESTING_RIGHT);
btrfs_set_lock_blocking_write(right);
right_nr = btrfs_header_nritems(right);
@@ -3742,7 +3742,7 @@ static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
if (IS_ERR(right))
return 1;
- btrfs_tree_lock(right);
+ __btrfs_tree_lock(right, BTRFS_NESTING_RIGHT);
btrfs_set_lock_blocking_write(right);
free_space = btrfs_leaf_free_space(right);
@@ -3975,7 +3975,7 @@ static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
if (IS_ERR(left))
return 1;
- btrfs_tree_lock(left);
+ __btrfs_tree_lock(left, BTRFS_NESTING_LEFT);
btrfs_set_lock_blocking_write(left);
free_space = btrfs_leaf_free_space(left);
@@ -5393,7 +5393,7 @@ int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
if (!ret) {
btrfs_set_path_blocking(path);
__btrfs_tree_read_lock(next,
- BTRFS_NESTING_NORMAL,
+ BTRFS_NESTING_RIGHT,
path->recurse);
}
next_rw_lock = BTRFS_READ_LOCK;
@@ -5430,7 +5430,7 @@ int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
if (!ret) {
btrfs_set_path_blocking(path);
__btrfs_tree_read_lock(next,
- BTRFS_NESTING_NORMAL,
+ BTRFS_NESTING_RIGHT,
path->recurse);
}
next_rw_lock = BTRFS_READ_LOCK;
@@ -27,6 +27,18 @@ enum btrfs_lock_nesting {
*/
BTRFS_NESTING_COW,
+ /*
+ * Oftentimes we need to lock adjacent nodes on the same level while
+ * still holding the lock on the original node we searched to, such as
+ * for searching forward or for split/balance.
+ *
+ * Because of this we need to indicate to lockdep that this is
+ * acceptable by having a different subclass for each of these
+ * operations.
+ */
+ BTRFS_NESTING_LEFT,
+ BTRFS_NESTING_RIGHT,
+
/*
* We are limited to MAX_LOCKDEP_SUBLCLASSES number of subclasses, so
* add this in here and add a static_assert to keep us from going over
Our lockdep maps are based on rootid+level, however in some cases we will lock adjacent blocks on the same level, namely in searching forward or in split/balance. Because of this lockdep will complain, so we need a separate subclass to indicate to lockdep that these are different locks. lock leaf -> BTRFS_NESTING_NORMAL cow leaf -> BTRFS_NESTING_COW split leaf lock left -> BTRFS_NESTING_LEFT lock right -> BTRFS_NESTING_RIGHT The above graph illustrates the need for this new nesting subclass. Signed-off-by: Josef Bacik <josef@toxicpanda.com> --- fs/btrfs/ctree.c | 16 ++++++++-------- fs/btrfs/locking.h | 12 ++++++++++++ 2 files changed, 20 insertions(+), 8 deletions(-)