xfs: defer agfl block frees

Hi all,

Here's a non-rfc version of the defer AGFL frees patches. As a quick summary, the purpose of this series is to reduce per-tx log reservation consumption of the block allocation code. Under certain conditions, the pre-allocation AGFL fix up code can end up performing multiple block free operations that can result in multiple btree shape changes before the originally requested allocation even begins. This leads to log reservation overrun problems because the number of AGFL block frees required for a particular transaction cannot be determined in advance. Therefore, process frees of AGFL blocks using deferred operations in the same way that data blocks are freed.

In conjunction, clean up some of the disparate dfops callchain plumbing by allowing a transaction to carry a pointer to an associated dop structure. This eliminates the need to plumb xfs_defer_ops through yet another callchain for the purpose of deferring AGFL frees. It also facilitates cleanups of similar codepaths where dfops is already passed around separately from the transaction that will ultimately log the associated intents.

There aren't that many code changes since rfcv2. The series has been rebased to for-next and the assignment of ->t_dfops occurs within xfs_defer_init() rather than being open-coded. Also, the series has seen more testing and drops some of the related test code from the rfc.

Thoughts, reviews, flames appreciated.

Brian

v1:
- Rebased to for-next.
- Attach dfops to tp via xfs_defer_init().
- Fix up xfs_defer_finish() to restore original pointer.
- Dropped debug/test patches.
rfcv2: https://marc.info/?l=linux-xfs&m=151681946702093&w=2
- Use transaction to carry deferred ops struct to allocation context.
- Remove dfops param from dir interfaces where possible.
- Defer AGFL block frees from more contexts.
- Define runtime stat for transaction regrant and logcount patch (to be potentially removed).
rfcv1: https://marc.info/?l=linux-xfs&m=151267309423883&w=2

Brian Foster (7):
xfs: create agfl block free helper function
xfs: allow attach of dfops to transaction
xfs: defer agfl block frees when dfops is available
xfs: defer agfl block frees from deferred ops processing context
xfs: defer agfl frees from inode inactivation
xfs: defer frees from common inode allocation paths
xfs: defer agfl frees from directory op transactions

 fs/xfs/libxfs/xfs_alloc.c       | 82 +++++++++++++++++++++++++++++++++++------
 fs/xfs/libxfs/xfs_alloc.h       |  2 +
 fs/xfs/libxfs/xfs_attr.c        | 18 ++++-----
 fs/xfs/libxfs/xfs_attr_remote.c |  6 +--
 fs/xfs/libxfs/xfs_bmap.c        |  4 +-
 fs/xfs/libxfs/xfs_defer.c       | 17 ++++++++-
 fs/xfs/libxfs/xfs_defer.h       |  4 +-
 fs/xfs/libxfs/xfs_dir2.c        | 16 ++++----
 fs/xfs/libxfs/xfs_dir2.h        |  9 ++---
 fs/xfs/libxfs/xfs_ialloc.c      |  6 +--
 fs/xfs/libxfs/xfs_ialloc.h      |  1 -
 fs/xfs/libxfs/xfs_refcount.c    |  2 +-
 fs/xfs/xfs_bmap_util.c          | 12 +++---
 fs/xfs/xfs_dquot.c              |  2 +-
 fs/xfs/xfs_inode.c              | 76 +++++++++++++++++++-------------------
 fs/xfs/xfs_inode.h              |  3 +-
 fs/xfs/xfs_iomap.c              |  6 +--
 fs/xfs/xfs_log_recover.c        |  2 +-
 fs/xfs/xfs_reflink.c            |  8 ++--
 fs/xfs/xfs_rtalloc.c            |  2 +-
 fs/xfs/xfs_symlink.c            |  6 +--
 fs/xfs/xfs_trace.h              |  2 +
 fs/xfs/xfs_trans.c              | 11 ++++--
 fs/xfs/xfs_trans.h              |  1 +
 fs/xfs/xfs_trans_extfree.c      | 70 +++++++++++++++++++++++++++++++++++
 25 files changed, 259 insertions(+), 109 deletions(-)

2.13.6