xfs: fix EFI recovery livelocks This series fixes a customer-reported transaction reservation bug introduced ten years ago that could result in livelocks during log recovery. Log intent item recovery single-steps each step of a deferred op chain, which means that each step only needs to allocate one transaction's worth of space in the log, not an entire chain all at once. This single-stepping is critical to unpinning the log tail since there's nobody else to do it for us. This has been lightly tested with fstests. Enjoy! Signed-off-by: Darrick J. Wong <djwong@kernel.org>