In the Linux kernel, the following vulnerability has been resolved:

btrfs: clear free space tree creation state on rebuild failure

btrfs_rebuild_free_space_tree() sets BTRFS_FS_CREATING_FREE_SPACE_TREE
before rebuilding the free space tree.  Several error paths return
without clearing this flag.

The transaction restart failure path can leave the flag set on a live
filesystem, causing delayed reference processing to be skipped. Clear it
on all free space tree rebuild failure paths. Keep
BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED set, since a failed rebuild leaves
the free space tree untrusted. Callers must fall back to extent-tree
caching.