hfsplus: fix potential race conditions in b-tree functionality

hfsplus: fix potential race conditions in b-tree functionality

The HFS_BNODE_DELETED flag is checked in hfs_bnode_put()
under locked tree->hash_lock. This patch adds locking
for the case of setting the HFS_BNODE_DELETED flag in
hfs_bnode_unlink() with the goal to avoid potential
race conditions.

The hfs_btree_write() method should be called under
tree->tree_lock. This patch reworks logic by adding
locking the tree->tree_lock for the calls of
hfs_btree_write() in hfsplus_cat_write_inode() and
hfsplus_system_write_inode().

This patch adds also the lockdep_assert_held() in
hfs_bmap_reserve(), hfs_bmap_alloc(), and hfs_bmap_free().

cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
cc: Yangtao Li <frank.li@vivo.com>
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Viacheslav Dubeyko <slava@dubeyko.com>
Link: https://lore.kernel.org/r/20260403230556.614171-2-slava@dubeyko.com
Signed-off-by: Viacheslav Dubeyko <slava@dubeyko.com>