From: Qu Wenruo <wqu@suse.com>
To: linux-btrfs@vger.kernel.org
Cc: josef@toxicpanda.com, Johannes.Thumshirn@wdc.com
Subject: [PATCH v4 0/6] btrfs: subpage + zoned fixes
Date: Sat, 11 May 2024 09:45:16 +0930 [thread overview]
Message-ID: <cover.1715386434.git.wqu@suse.com> (raw)
[CHANGELOG]
v4:
- Rebased to the latest for-next branch
Thankfully no conflicts at all.
- Include all the previous preparation patches
It turns out I split the preparation into other series and even get
myself confused.
- Use the correct commit message from my local branch
It turns out Josef is totally correct, the problem I described in
"btrfs: do no clera page dirty inside extent_write_locked_range()" is
really confusing, it has direct IO involved and my local branch is
already using a much better commit and I just forgot it.
v3:
- Use the minimal fsstress workload with trace_printk() output to
explain the bug better
v2:
- Update the commit message for the first patch
As there is something wrong with the ASCII art of the memory layout.
[REPO]
https://github.com/adam900710/linux/tree/subpage_delalloc
If running subpage with zoned devices (TCMU emulated HDD, 64K or 16K
page size with 4K sectorsize), btrfs can easily hitting various bugs:
- ASSERT()s related to submitting page range which has no OE coverage
- Various reserved space leakage and some OE never finished
This is caused by two major reasons:
- run_delalloc_cow() is not subpage compatible
Thus we may try to submit pages which has no OE for it.
This would be addressed by patch 1~4
- Some dirty range is not submitted thus OE would never finish
This happens due to the mismatch that extent_write_locked_range() can
clear the full page dirty, even if we're only submitting part of the
dirty ranges.
Then later __extent_writepage_io() would refuse to submit a non-dirty
page, and the check is only checking the full page dirty flag, not the
subpage bitmaps.
This would be addressed by patch 5~6.
Qu Wenruo (6):
btrfs: make __extent_writepage_io() to write specified range only
btrfs: lock subpage ranges in one go for writepage_delalloc()
btrfs: subpage: introduce helpers to handle subpage delalloc locking
btrfs: migrate writepage_delalloc() to use subpage helpers
btrfs: do not clear page dirty inside extent_write_locked_range()
btrfs: make extent_write_locked_range() to handle subpage writeback
correctly
fs/btrfs/extent_io.c | 105 +++++++++++++++++++++++++------
fs/btrfs/subpage.c | 144 +++++++++++++++++++++++++++++++++++++++++--
fs/btrfs/subpage.h | 10 ++-
3 files changed, 233 insertions(+), 26 deletions(-)
--
2.45.0
next reply other threads:[~2024-05-11 0:15 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-11 0:15 Qu Wenruo [this message]
2024-05-11 0:15 ` [PATCH v4 1/6] btrfs: make __extent_writepage_io() to write specified range only Qu Wenruo
2024-05-12 16:31 ` Johannes Thumshirn
2024-05-11 0:15 ` [PATCH v4 2/6] btrfs: lock subpage ranges in one go for writepage_delalloc() Qu Wenruo
2024-05-12 17:08 ` Johannes Thumshirn
2024-05-12 22:09 ` Qu Wenruo
2024-05-11 0:15 ` [PATCH v4 3/6] btrfs: subpage: introduce helpers to handle subpage delalloc locking Qu Wenruo
2024-05-12 17:10 ` Johannes Thumshirn
2024-05-11 0:15 ` [PATCH v4 4/6] btrfs: migrate writepage_delalloc() to use subpage helpers Qu Wenruo
2024-05-12 17:14 ` Johannes Thumshirn
2024-05-11 0:15 ` [PATCH v4 5/6] btrfs: do not clear page dirty inside extent_write_locked_range() Qu Wenruo
2024-05-12 17:19 ` Johannes Thumshirn
2024-05-11 0:15 ` [PATCH v4 6/6] btrfs: make extent_write_locked_range() to handle subpage writeback correctly Qu Wenruo
2024-05-12 17:21 ` Johannes Thumshirn
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