Merge tag 'v6.11' into for-6.12/block

Merge in 6.11 final to get the fix for preventing deadlocks on an
elevator switch, as there's a fixup for that patch.

* tag 'v6.11': (1788 commits)
  Linux 6.11
  Revert "KVM: VMX: Always honor guest PAT on CPUs that support self-snoop"
  pinctrl: pinctrl-cy8c95x0: Fix regcache
  cifs: Fix signature miscalculation
  mm: avoid leaving partial pfn mappings around in error case
  drm/xe/client: add missing bo locking in show_meminfo()
  drm/xe/client: fix deadlock in show_meminfo()
  drm/xe/oa: Enable Xe2+ PES disaggregation
  drm/xe/display: fix compat IS_DISPLAY_STEP() range end
  drm/xe: Fix access_ok check in user_fence_create
  drm/xe: Fix possible UAF in guc_exec_queue_process_msg
  drm/xe: Remove fence check from send_tlb_invalidation
  drm/xe/gt: Remove double include
  net: netfilter: move nf flowtable bpf initialization in nf_flow_table_module_init()
  PCI: Fix potential deadlock in pcim_intx()
  workqueue: Clear worker->pool in the worker thread context
  net: tighten bad gso csum offset check in virtio_net_hdr
  netlink: specs: mptcp: fix port endianness
  net: dpaa: Pad packets to ETH_ZLEN
  mptcp: pm: Fix uaf in __timer_delete_sync
  ...

1 files changed, 67 insertions, 0 deletions

diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c
index 2ac9296edccb..06a9e0542d70 100644
--- a/fs/btrfs/delayed-ref.c
+++ b/fs/btrfs/delayed-ref.c
@@ -1134,6 +1134,73 @@ btrfs_find_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs, u64 byt
 	return find_ref_head(delayed_refs, bytenr, false);
 }
 
+static int find_comp(struct btrfs_delayed_ref_node *entry, u64 root, u64 parent)
+{
+	int type = parent ? BTRFS_SHARED_BLOCK_REF_KEY : BTRFS_TREE_BLOCK_REF_KEY;
+
+	if (type < entry->type)
+		return -1;
+	if (type > entry->type)
+		return 1;
+
+	if (type == BTRFS_TREE_BLOCK_REF_KEY) {
+		if (root < entry->ref_root)
+			return -1;
+		if (root > entry->ref_root)
+			return 1;
+	} else {
+		if (parent < entry->parent)
+			return -1;
+		if (parent > entry->parent)
+			return 1;
+	}
+	return 0;
+}
+
+/*
+ * Check to see if a given root/parent reference is attached to the head.  This
+ * only checks for BTRFS_ADD_DELAYED_REF references that match, as that
+ * indicates the reference exists for the given root or parent.  This is for
+ * tree blocks only.
+ *
+ * @head: the head of the bytenr we're searching.
+ * @root: the root objectid of the reference if it is a normal reference.
+ * @parent: the parent if this is a shared backref.
+ */
+bool btrfs_find_delayed_tree_ref(struct btrfs_delayed_ref_head *head,
+				 u64 root, u64 parent)
+{
+	struct rb_node *node;
+	bool found = false;
+
+	lockdep_assert_held(&head->mutex);
+
+	spin_lock(&head->lock);
+	node = head->ref_tree.rb_root.rb_node;
+	while (node) {
+		struct btrfs_delayed_ref_node *entry;
+		int ret;
+
+		entry = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
+		ret = find_comp(entry, root, parent);
+		if (ret < 0) {
+			node = node->rb_left;
+		} else if (ret > 0) {
+			node = node->rb_right;
+		} else {
+			/*
+			 * We only want to count ADD actions, as drops mean the
+			 * ref doesn't exist.
+			 */
+			if (entry->action == BTRFS_ADD_DELAYED_REF)
+				found = true;
+			break;
+		}
+	}
+	spin_unlock(&head->lock);
+	return found;
+}
+
 void __cold btrfs_delayed_ref_exit(void)
 {
 	kmem_cache_destroy(btrfs_delayed_ref_head_cachep);