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From:   Liu Bo <obuil.liubo@gmail.com>
Date:   Mon, 22 Oct 2018 17:23:36 -0700
Message-ID: <CANQeFDB6Qy_=E1GD6i6f3VaU0CiKQBr7td1=8gbvZYZ3ui88Yg@mail.gmail.com>
Subject: Re: [GIT PULL] Btrfs updates for 4.20, part 1
To:     David Sterba <dsterba@suse.com>
Cc:     torvalds@linux-foundation.org, Chris Mason <clm@fb.com>,
        linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org
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On Mon, Oct 22, 2018 at 10:24 AM David Sterba <dsterba@suse.com> wrote:
>
> Hi,
>
> this is the first batch with fixes and some nice performance improvements.
>
> Preliminary results show eg. more files/sec in fsmark, better perf on
> multi-threaded workloads (filebench, dbench), fewer context switches and
> overall better memory allocation characteristics (multiple benchmarks).
>
> Apart from general performance, there's an improvement for qgroups +
> balance workload that's been troubling our users.
>
> Note for stable: there are 20+ patches tagged for stable, out of 90. Not
> all of them apply cleanly on all stable versions but the conflicts are
> mostly due to simple cleanups and resolving should be obvious. The fixes
> are otherwise independent.
>
> No merge conflicts expected. Please pull, thanks.
>
>
> Performance improvements:
>
> * blocking mode of path is gone, means that only the spinning mode is used;

I'd like to do a few corrections here, the transition from the
spinning mode to blocking mode is removed, we still need blocking mode
of path for sleeping context.

thanks,
liubo
>   the blocking resulted in more unnecessary wakeups and updates to the path
>   locks, the effects are measurable and improve latency and scaleability
>

> * qgroups: first batch of changes that should speedup balancing with qgroups
>   on, skip quota accounting on unchanged subtrees, overall gain is about 30+%
>   in runtime
>
> * use rb-tree with cached first node for several structures, small improvement
>   to avoid pointer chasing
>
> Fixes:
>
> * trim
>   * fix: some blockgroups could have been missed if their logical address was
>     past the total filesystem size (ie. after a lot of balancing)
>   * better error reporting, after processing blockgroups and whole device
>   * fix: continue trimming block groups after an error is encountered
>   * check for trim support of the device earlier and avoid some unnecessary work
>   * less interaction with transaction commit that improves latency on slower
>     storage (eg. image files over NFS)
>
> * fsync
>   * fix warning when replaying log after fsync of a O_TMPFILE
>   * fix wrong dentries after fsync of file that got its parent replaced
>
> * qgroups: fix rescan that might misc some dirty groups
>
> * don't clean dirty pages during buffered writes, this could lead to lost
>   updates in some corner cases
>
> * some block groups could have been delayed in creation, if the allocation
>   triggered another one
>
> * error handling improvements
>
> Cleanups:
>
>   * removed unused struct members and variables
>   * function return type cleanups
>   * delayed refs code refactoring
>
> * protect against deadlock that could be caused by crafted image that tries to
>   allocate from a tree that's locked already
>
> ----------------------------------------------------------------
> The following changes since commit 35a7f35ad1b150ddf59a41dcac7b2fa32982be0e:
>
>   Linux 4.19-rc8 (2018-10-15 07:20:24 +0200)
>
> are available in the Git repository at:
>
>   git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux.git for-4.20-part1-tag
>
> for you to fetch changes up to d9352794dad9f28535439d85a815978878c141ab:
>
>   btrfs: switch return_bigger to bool in find_ref_head (2018-10-15 17:23:41 +0200)
>
> ----------------------------------------------------------------
> Anand Jain (2):
>       btrfs: add assertions where number of devices could go below 0
>       btrfs: add helper to obtain number of devices with ongoing dev-replace
>
> Chris Mason (1):
>       Btrfs: don't clean dirty pages during buffered writes
>
> Colin Ian King (2):
>       btrfs: remove unused pointer inode in relink_file_extents
>       btrfs: remove unused pointer 'tree' in btrfs_submit_compressed_read
>
> David Sterba (12):
>       btrfs: tests: add separate stub for find_lock_delalloc_range
>       btrfs: tests: move testing members of struct btrfs_root to the end
>       btrfs: tests: group declarations of self-test helpers
>       btrfs: tests: polish ifdefs around testing helper
>       btrfs: use common helper instead of open coding a bit test
>       btrfs: remove btrfs_dev_replace::read_locks
>       btrfs: open code btrfs_dev_replace_clear_lock_blocking
>       btrfs: open code btrfs_dev_replace_stats_inc
>       btrfs: open code btrfs_after_dev_replace_commit
>       btrfs: dev-replace: avoid useless lock on error handling path
>       btrfs: dev-replace: move replace members out of fs_info
>       btrfs: dev-replace: remove pointless assert in write unlock
>
> Filipe Manana (2):
>       Btrfs: fix warning when replaying log after fsync of a tmpfile
>       Btrfs: fix wrong dentries after fsync of file that got its parent replaced
>
> Jeff Mahoney (5):
>       btrfs: fix error handling in free_log_tree
>       btrfs: fix error handling in btrfs_dev_replace_start
>       btrfs: iterate all devices during trim, instead of fs_devices::alloc_list
>       btrfs: don't attempt to trim devices that don't support it
>       btrfs: keep trim from interfering with transaction commits
>
> Josef Bacik (7):
>       btrfs: wait on caching when putting the bg cache
>       btrfs: release metadata before running delayed refs
>       btrfs: protect space cache inode alloc with GFP_NOFS
>       btrfs: reset max_extent_size on clear in a bitmap
>       btrfs: make sure we create all new block groups
>       btrfs: assert on non-empty delayed iputs
>       btrfs: drop min_size from evict_refill_and_join
>
> Liu Bo (19):
>       Btrfs: do not unnecessarily pass write_lock_level when processing leaf
>       Btrfs: remove always true if branch in btrfs_get_extent
>       Btrfs: use next_state in find_first_extent_bit
>       btrfs: free path at an earlier point in btrfs_get_extent
>       Btrfs: remove confusing tracepoint in btrfs_add_reserved_bytes
>       Btrfs: fix alignment in declaration and prototype of btrfs_get_extent
>       Btrfs: set leave_spinning in btrfs_get_extent
>       Btrfs: use args in the correct order for kcalloc in btrfsic_read_block
>       Btrfs: unify error handling of btrfs_lookup_dir_item
>       Btrfs: remove unnecessary level check in balance_level
>       Btrfs: assert page dirty bit on extent buffer pages
>       Btrfs: skip set_page_dirty if eb pages are already dirty
>       Btrfs: remove wait_ordered_range in btrfs_evict_inode
>       Btrfs: delayed-refs: use rb_first_cached for href_root
>       Btrfs: delayed-refs: use rb_first_cached for ref_tree
>       Btrfs: delayed-inode: use rb_first_cached for ins_root and del_root
>       Btrfs: extent_map: use rb_first_cached
>       Btrfs: preftree: use rb_first_cached
>       Btrfs: kill btrfs_clear_path_blocking
>
> Lu Fengqi (10):
>       btrfs: simplify the send_in_progress check in btrfs_delete_subvolume
>       btrfs: switch update_size to bool in btrfs_block_rsv_migrate and btrfs_rsv_add_bytes
>       btrfs: Remove root parameter from btrfs_insert_dir_item
>       btrfs: remove a useless return statement in btrfs_block_rsv_add
>       btrfs: qgroup: move the qgroup->members check out from (!qgroup)'s else branch
>       btrfs: delayed-ref: pass delayed_refs directly to btrfs_select_ref_head
>       btrfs: delayed-ref: pass delayed_refs directly to btrfs_delayed_ref_lock
>       btrfs: remove fs_info from btrfs_check_space_for_delayed_refs
>       btrfs: remove fs_info from btrfs_should_throttle_delayed_refs
>       btrfs: switch return_bigger to bool in find_ref_head
>
> Misono Tomohiro (2):
>       btrfs: Remove 'objectid' member from struct btrfs_root
>       btrfs: remove redundant variable from btrfs_cross_ref_exist
>
> Nikolay Borisov (8):
>       btrfs: Make btrfs_find_device_by_path return struct btrfs_device
>       btrfs: Make btrfs_find_device_missing_or_by_path return directly a device
>       btrfs: Make btrfs_find_device_by_devspec return btrfs_device directly
>       btrfs: Remove logically dead code from btrfs_orphan_cleanup
>       btrfs: handle error of get_old_root
>       btrfs: Factor out ref head locking code in __btrfs_run_delayed_refs
>       btrfs: Factor out loop processing all refs of a head
>       btrfs: refactor __btrfs_run_delayed_refs loop
>
> Omar Sandoval (2):
>       Btrfs: clean up scrub is_dev_replace parameter
>       Btrfs: get rid of btrfs_symlink_aops
>
> Qu Wenruo (16):
>       btrfs: qgroup: Dirty all qgroups before rescan
>       btrfs: Handle owner mismatch gracefully when walking up tree
>       btrfs: locking: Add extra check in btrfs_init_new_buffer() to avoid deadlock
>       btrfs: Enhance btrfs_trim_fs function to handle error better
>       btrfs: Ensure btrfs_trim_fs can trim the whole filesystem
>       btrfs: relocation: Add basic extent backref related comments for build_backref_tree
>       btrfs: qgroup: Introduce trace event to analyse the number of dirty extents accounted
>       btrfs: qgroup: Introduce function to trace two swaped extents
>       btrfs: qgroup: Introduce function to find all new tree blocks of reloc tree
>       btrfs: qgroup: Use generation-aware subtree swap to mark dirty extents
>       btrfs: qgroup: Don't trace subtree if we're dropping reloc tree
>       btrfs: qgroup: Only trace data extents in leaves if we're relocating data block group
>       btrfs: tree-checker: Check level for leaves and nodes
>       btrfs: qgroup: Avoid calling qgroup functions if qgroup is not enabled
>       btrfs: relocation: Cleanup while loop using rbtree_postorder_for_each_entry_safe
>       btrfs: relocation: Remove redundant tree level check
>
> Su Yue (1):
>       btrfs: defrag: use btrfs_mod_outstanding_extents in cluster_pages_for_defrag
>
> zhong jiang (4):
>       btrfs: remove unneeded NULL checks before kfree
>       btrfs: change btrfs_free_reserved_bytes to return void
>       btrfs: change btrfs_pin_log_trans to return void
>       btrfs: change remove_extent_mapping to return void
>
>  fs/btrfs/backref.c                |  39 ++--
>  fs/btrfs/btrfs_inode.h            |   8 +-
>  fs/btrfs/check-integrity.c        |   6 +-
>  fs/btrfs/compression.c            |   2 -
>  fs/btrfs/ctree.c                  |  68 +-----
>  fs/btrfs/ctree.h                  |  56 ++---
>  fs/btrfs/delayed-inode.c          |  41 ++--
>  fs/btrfs/delayed-inode.h          |   4 +-
>  fs/btrfs/delayed-ref.c            |  69 +++---
>  fs/btrfs/delayed-ref.h            |  10 +-
>  fs/btrfs/dev-replace.c            |  64 ++----
>  fs/btrfs/dev-replace.h            |   8 -
>  fs/btrfs/dir-item.c               |   8 +-
>  fs/btrfs/disk-io.c                |  24 +-
>  fs/btrfs/export.c                 |   4 +-
>  fs/btrfs/extent-tree.c            | 424 +++++++++++++++++++++--------------
>  fs/btrfs/extent_io.c              |  33 ++-
>  fs/btrfs/extent_io.h              |   4 +-
>  fs/btrfs/extent_map.c             |  32 +--
>  fs/btrfs/extent_map.h             |   4 +-
>  fs/btrfs/file.c                   |  33 ++-
>  fs/btrfs/free-space-cache.c       |  16 +-
>  fs/btrfs/inode.c                  | 120 ++++------
>  fs/btrfs/ioctl.c                  |  18 +-
>  fs/btrfs/qgroup.c                 | 455 ++++++++++++++++++++++++++++++++++++--
>  fs/btrfs/qgroup.h                 |   8 +
>  fs/btrfs/ref-verify.c             |   8 +-
>  fs/btrfs/relocation.c             |  74 +++----
>  fs/btrfs/scrub.c                  |  34 ++-
>  fs/btrfs/send.c                   |  24 +-
>  fs/btrfs/super.c                  |   6 +-
>  fs/btrfs/tests/extent-io-tests.c  |  10 +-
>  fs/btrfs/tests/extent-map-tests.c |   4 +-
>  fs/btrfs/transaction.c            |  31 +--
>  fs/btrfs/tree-checker.c           |  14 ++
>  fs/btrfs/tree-log.c               |  86 +++++--
>  fs/btrfs/tree-log.h               |   2 +-
>  fs/btrfs/volumes.c                | 117 +++++-----
>  fs/btrfs/volumes.h                |   9 +-
>  include/trace/events/btrfs.h      |  36 ++-
>  40 files changed, 1268 insertions(+), 745 deletions(-)