[PATCH v4 0/4] xfs: support shrinking free space in the last AG

[Gao Xiang <hsiangkao@redhat.com>]

Hi folks,

v3: https://lore.kernel.org/r/20210108190919.623672-1-hsiangkao@redhat.com

This patchset attempts to support shrinking free space in the last AG.
Days ago I also made a shrinking the entire AGs prototype at,
https://git.kernel.org/pub/scm/linux/kernel/git/xiang/linux.git/log/?h=xfs/shrink2
which is still WIP / rather incomplete, yet any directions/suggestions
about that would be greatly helpful to me as well.

Kindly leave your thoughts, insights about this. Thanks!

xfsprogs: https://lore.kernel.org/r/20201028114010.545331-1-hsiangkao@redhat.com
xfstests: https://lore.kernel.org/r/20201028230909.639698-1-hsiangkao@redhat.com

Thanks,
Gao Xiang

Changes since v3:
 - [1/4] make division/mod have its own variable (Darrick);
 - [2/4] leave xfs_growfs_{data,log}_t definitions alone (Darrick, Eric, Dave);
 - [4/4] switch `delta' to int64_t (Darrick);
       * however, we couldn't let (delta {>,<} 0) be {growfs,shrinkfs}
         since laterly `delta' becomes the adjusted delta value of last AG
         due to the original growfs design, so I still keep `bool extend`
         variable this time.
 - collect some RVB tags from v3.

Gao Xiang (4):
  xfs: rename `new' to `delta' in xfs_growfs_data_private()
  xfs: get rid of xfs_growfs_{data,log}_t
  xfs: hoist out xfs_resizefs_init_new_ags()
  xfs: support shrinking unused space in the last AG

 fs/xfs/libxfs/xfs_ag.c |  72 +++++++++++++++++++
 fs/xfs/libxfs/xfs_ag.h |   2 +
 fs/xfs/xfs_fsops.c     | 160 ++++++++++++++++++++++++++---------------
 fs/xfs/xfs_fsops.h     |   4 +-
 fs/xfs/xfs_ioctl.c     |   4 +-
 fs/xfs/xfs_trans.c     |   1 -
 6 files changed, 181 insertions(+), 62 deletions(-)

-- 
2.27.0