simple synchronous read repair v2

From: Christoph Hellwig <hch@lst.de>
To: Chris Mason <clm@fb.com>, Josef Bacik <josef@toxicpanda.com>,
	David Sterba <dsterba@suse.com>
Cc: Qu Wenruo <wqu@suse.com>, linux-btrfs@vger.kernel.org
Subject: simple synchronous read repair v2
Date: Fri, 27 May 2022 10:43:11 +0200	[thread overview]
Message-ID: <20220527084320.2130831-1-hch@lst.de> (raw)

Hi all,

this is my take on the read repair code.  It borrow a lot of concepts
and patches from Qu's attempt.  The big difference is that it does away
with multiple in-flight repair bios, but instead just does one at a
time, but tries to make it as big as possible.

My aim here is mostly to fix up the messy I/O completions for the
direct I/O path, that make further bio optimizations rather annoying,
but it also gives better I/O patterns for repair (although I'm not sure
anyone cares) and removes a fair chunk of code.

[this is on top of a not commit yet series.  I kinda hate doing that, but
 with all the hot repair discussion going on right now we might as well
 have an uptodate version of this series out on the list]

Git tree:

   git://git.infradead.org/users/hch/misc.git btrfs-read_repair

Gitweb:

   http://git.infradead.org/users/hch/misc.git/shortlog/refs/heads/btrfs-read_repair

Changes since v1:
 - rebased on top of the "misc btrfs cleanups" series that contains
   various patches previously in this series and the
   "cleanup btrfs bio handling, part 2 v4" series
 - handle partial reads due to checksum failures
 - handle large I/O for parity RAID repair as well
 - add a lot more comments
 - rename btrfs_read_repair_end to btrfs_read_repair_finish

Diffstat:
 fs/btrfs/Makefile            |    2 
 fs/btrfs/btrfs_inode.h       |    5 
 fs/btrfs/extent-io-tree.h    |   15 -
 fs/btrfs/extent_io.c         |  570 ++++---------------------------------------
 fs/btrfs/extent_io.h         |   25 -
 fs/btrfs/inode.c             |   55 +---
 fs/btrfs/read-repair.c       |  248 ++++++++++++++++++
 fs/btrfs/read-repair.h       |   33 ++
 fs/btrfs/super.c             |    9 
 fs/btrfs/volumes.c           |   97 +++++++
 fs/btrfs/volumes.h           |    2 
 include/trace/events/btrfs.h |    1 
 12 files changed, 467 insertions(+), 595 deletions(-)