[RFE] add zoned storage stats into the XFS metrics

[natoscott]

Details of patches arriving in latest kernels follows (see email below).
Background information about zoned storage here: https://zonedstorage.io/docs/filesystems/xfs

---------- Forwarded message ---------
From: Christoph Hellwig hch@lst.de
Date: Fri, Jan 30, 2026 at 4:20 PM
Subject: stats and error injection for zoned GC v2
To: Carlos Maiolino cem@kernel.org
Cc: Hans Holmberg hans.holmberg@wdc.com, Darrick J. Wong djwong@kernel.org, linux-xfs@vger.kernel.org

Hi all,

this series adds error injection for zoned resets and zoned GC stats.
My initial use is for a test case that verifies zone reset error
handling, but that stats should also be very useful for monitoring
tools like PCP and benchmarking.

As part of the error injection work I've also added a mount option to
enable error ibjection at mount time so that it can exercise the
mount code as well and cleaned up various other bits of the error
injection code.

Changes since v1:
 - improve the errortag mount option documentation
 - rename the defer_log stat to match all the others
 - rename xs_gc_write_bytes to xs_gc_bytes and correctly track it

Diffstat:
 Documentation/admin-guide/xfs.rst |    8 ++
 fs/xfs/libxfs/xfs_defer.c         |    2
 fs/xfs/libxfs/xfs_errortag.h      |    8 +-
 fs/xfs/xfs_error.c                |  142 +++++++++++++++++++++-----------------
 fs/xfs/xfs_error.h                |   23 ++----
 fs/xfs/xfs_stats.c                |   12 ++-
 fs/xfs/xfs_stats.h                |    8 +-
 fs/xfs/xfs_super.c                |   20 +++++
 fs/xfs/xfs_zone_gc.c              |   72 ++++++++++++-------
 9 files changed, 186 insertions(+), 109 deletions(-)