From: Qu Wenruo <wqu@suse.com>
To: linux-btrfs@vger.kernel.org
Subject: [Patch v2 35/42] btrfs: fix wild subpage writeback which does not have ordered extent.
Date: Wed, 28 Apr 2021 07:03:42 +0800 [thread overview]
Message-ID: <20210427230349.369603-36-wqu@suse.com> (raw)
In-Reply-To: <20210427230349.369603-1-wqu@suse.com>
[BUG]
When running fsstress with subpage RW support, there are random
BUG_ON()s triggered with the following trace:
kernel BUG at fs/btrfs/file-item.c:667!
Internal error: Oops - BUG: 0 [#1] SMP
CPU: 1 PID: 3486 Comm: kworker/u13:2 Tainted: G WC O 5.11.0-rc4-custom+ #43
Hardware name: Radxa ROCK Pi 4B (DT)
Workqueue: btrfs-worker-high btrfs_work_helper [btrfs]
pstate: 60000005 (nZCv daif -PAN -UAO -TCO BTYPE=--)
pc : btrfs_csum_one_bio+0x420/0x4e0 [btrfs]
lr : btrfs_csum_one_bio+0x400/0x4e0 [btrfs]
Call trace:
btrfs_csum_one_bio+0x420/0x4e0 [btrfs]
btrfs_submit_bio_start+0x20/0x30 [btrfs]
run_one_async_start+0x28/0x44 [btrfs]
btrfs_work_helper+0x128/0x1b4 [btrfs]
process_one_work+0x22c/0x430
worker_thread+0x70/0x3a0
kthread+0x13c/0x140
ret_from_fork+0x10/0x30
[CAUSE]
Above BUG_ON() means there are some bio range which doesn't have ordered
extent, which indeed is worthy a BUG_ON().
Unlike regular sectorsize == PAGE_SIZE case, in subpage we have extra
subpage dirty bitmap to record which range is dirty and should be
written back.
This means, if we submit bio for a subpage range, we do not only need to
clear page dirty, but also need to clear subpage dirty bits.
In __extent_writepage_io(), we will call btrfs_page_clear_dirty() for
any range we submit a bio.
But there is loophole, if we hit a range which is beyond isize, we just
call btrfs_writepage_endio_finish_ordered() to finish the ordered io,
then break out, without clearing the subpage dirty.
This means, if we hit above branch, the subpage dirty bits are still
there, if other range of the page get dirtied and we need to writeback
that page again, we will submit bio for the old range, leaving a wild
bio range which doesn't have ordered extent.
[FIX]
Fix it by always calling btrfs_page_clear_dirty() in
__extent_writepage_io().
Also to avoid such problem from happening again, add a new assert,
btrfs_page_assert_not_dirty(), to make sure both page dirty and subpage
dirty bits are cleared before exiting __extent_writepage_io().
Signed-off-by: Qu Wenruo <wqu@suse.com>
---
fs/btrfs/extent_io.c | 17 +++++++++++++++++
fs/btrfs/subpage.c | 16 ++++++++++++++++
fs/btrfs/subpage.h | 7 +++++++
3 files changed, 40 insertions(+)
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index bd2af133f9e4..697f65e4fe8f 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -3909,6 +3909,16 @@ static noinline_for_stack int __extent_writepage_io(struct btrfs_inode *inode,
if (cur >= i_size) {
btrfs_writepage_endio_finish_ordered(inode, page, cur,
end, 1);
+ /*
+ * This range is beyond isize, thus we don't need to
+ * bother writing back.
+ * But we still need to clear the dirty subpage bit, or
+ * the next time the page get dirtied, we will try to
+ * writeback the sectors with subpage diryt bits,
+ * causing writeback without ordered extent.
+ */
+ btrfs_page_clear_dirty(fs_info, page, cur,
+ end + 1 - cur);
break;
}
@@ -3959,6 +3969,7 @@ static noinline_for_stack int __extent_writepage_io(struct btrfs_inode *inode,
else
btrfs_writepage_endio_finish_ordered(inode,
page, cur, cur + iosize - 1, 1);
+ btrfs_page_clear_dirty(fs_info, page, cur, iosize);
cur += iosize;
continue;
}
@@ -3994,6 +4005,12 @@ static noinline_for_stack int __extent_writepage_io(struct btrfs_inode *inode,
cur += iosize;
nr++;
}
+ /*
+ * If we finishes without problem, we should not only clear page dirty,
+ * but also emptied subpage dirty bits
+ */
+ if (!ret)
+ btrfs_page_assert_not_dirty(fs_info, page);
*nr_ret = nr;
return ret;
}
diff --git a/fs/btrfs/subpage.c b/fs/btrfs/subpage.c
index 516e0b3f2ed9..696485ab68a2 100644
--- a/fs/btrfs/subpage.c
+++ b/fs/btrfs/subpage.c
@@ -548,3 +548,19 @@ IMPLEMENT_BTRFS_PAGE_OPS(writeback, set_page_writeback, end_page_writeback,
PageWriteback);
IMPLEMENT_BTRFS_PAGE_OPS(ordered, SetPageOrdered, ClearPageOrdered,
PageOrdered);
+
+void btrfs_page_assert_not_dirty(const struct btrfs_fs_info *fs_info,
+ struct page *page)
+{
+ struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private;
+
+ if (!IS_ENABLED(CONFIG_BTRFS_ASSERT))
+ return;
+
+ ASSERT(!PageDirty(page));
+ if (fs_info->sectorsize == PAGE_SIZE)
+ return;
+
+ ASSERT(PagePrivate(page) && page->private);
+ ASSERT(subpage->dirty_bitmap == 0);
+}
diff --git a/fs/btrfs/subpage.h b/fs/btrfs/subpage.h
index 3419b152c00f..7188e9d2fbea 100644
--- a/fs/btrfs/subpage.h
+++ b/fs/btrfs/subpage.h
@@ -119,4 +119,11 @@ DECLARE_BTRFS_SUBPAGE_OPS(ordered);
bool btrfs_subpage_clear_and_test_dirty(const struct btrfs_fs_info *fs_info,
struct page *page, u64 start, u32 len);
+/*
+ * Extra assert to make sure not only the page dirty bit is cleared, but also
+ * subpage dirty bit is cleared.
+ */
+void btrfs_page_assert_not_dirty(const struct btrfs_fs_info *fs_info,
+ struct page *page);
+
#endif
--
2.31.1
next prev parent reply other threads:[~2021-04-27 23:05 UTC|newest]
Thread overview: 117+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-27 23:03 [Patch v2 00/42] btrfs: add data write support for subpage Qu Wenruo
2021-04-27 23:03 ` [Patch v2 01/42] btrfs: scrub: fix subpage scrub repair error caused by hardcoded PAGE_SIZE Qu Wenruo
2021-05-13 22:57 ` David Sterba
2021-05-13 23:32 ` Qu Wenruo
2021-04-27 23:03 ` [Patch v2 02/42] btrfs: make free space cache size consistent across different PAGE_SIZE Qu Wenruo
2021-04-27 23:03 ` [Patch v2 03/42] btrfs: remove the unused parameter @len for btrfs_bio_fits_in_stripe() Qu Wenruo
2021-05-13 22:58 ` David Sterba
2021-05-13 23:07 ` David Sterba
2021-04-27 23:03 ` [Patch v2 04/42] btrfs: allow btrfs_bio_fits_in_stripe() to accept bio without any page Qu Wenruo
2021-04-27 23:03 ` [Patch v2 05/42] btrfs: refactor submit_extent_page() to make bio and its flag tracing easier Qu Wenruo
2021-05-13 23:03 ` David Sterba
2021-05-21 11:06 ` Johannes Thumshirn
2021-05-21 11:26 ` Qu Wenruo
2021-05-21 13:30 ` David Sterba
2021-04-27 23:03 ` [Patch v2 06/42] btrfs: make subpage metadata write path to call its own endio functions Qu Wenruo
2021-04-27 23:03 ` [Patch v2 07/42] btrfs: pass btrfs_inode into btrfs_writepage_endio_finish_ordered() Qu Wenruo
2021-05-13 23:06 ` David Sterba
2021-05-13 23:35 ` Qu Wenruo
2021-05-21 14:27 ` Josef Bacik
2021-05-21 20:22 ` David Sterba
2021-05-22 0:24 ` Qu Wenruo
2021-05-23 7:40 ` Qu Wenruo
2021-05-23 13:43 ` Josef Bacik
2021-05-23 13:50 ` Qu Wenruo
2021-05-23 14:08 ` Josef Bacik
2021-04-27 23:03 ` [Patch v2 08/42] btrfs: make Private2 lifespan more consistent Qu Wenruo
2021-04-27 23:03 ` [Patch v2 09/42] btrfs: refactor how we finish ordered extent io for endio functions Qu Wenruo
2021-05-13 23:11 ` David Sterba
2021-04-27 23:03 ` [Patch v2 10/42] btrfs: update the comments in btrfs_invalidatepage() Qu Wenruo
2021-04-27 23:03 ` [Patch v2 11/42] btrfs: introduce btrfs_lookup_first_ordered_range() Qu Wenruo
2021-05-13 23:13 ` David Sterba
2021-04-27 23:03 ` [Patch v2 12/42] btrfs: refactor btrfs_invalidatepage() Qu Wenruo
2021-04-27 23:03 ` [Patch v2 13/42] btrfs: rename PagePrivate2 to PageOrdered inside btrfs Qu Wenruo
2021-04-27 23:03 ` [Patch v2 14/42] btrfs: pass bytenr directly to __process_pages_contig() Qu Wenruo
2021-04-27 23:03 ` [Patch v2 15/42] btrfs: refactor the page status update into process_one_page() Qu Wenruo
2021-04-27 23:03 ` [Patch v2 16/42] btrfs: provide btrfs_page_clamp_*() helpers Qu Wenruo
2021-04-27 23:03 ` [Patch v2 17/42] btrfs: only require sector size alignment for end_bio_extent_writepage() Qu Wenruo
2021-04-27 23:03 ` [Patch v2 18/42] btrfs: make btrfs_dirty_pages() to be subpage compatible Qu Wenruo
2021-04-27 23:03 ` [Patch v2 19/42] btrfs: make __process_pages_contig() to handle subpage dirty/error/writeback status Qu Wenruo
2021-04-27 23:03 ` [Patch v2 20/42] btrfs: make end_bio_extent_writepage() to be subpage compatible Qu Wenruo
2021-04-27 23:03 ` [Patch v2 21/42] btrfs: make process_one_page() to handle subpage locking Qu Wenruo
2021-04-27 23:03 ` [Patch v2 22/42] btrfs: introduce helpers for subpage ordered status Qu Wenruo
2021-04-27 23:03 ` [Patch v2 23/42] btrfs: make page Ordered bit to be subpage compatible Qu Wenruo
2021-04-27 23:03 ` [Patch v2 24/42] btrfs: update locked page dirty/writeback/error bits in __process_pages_contig Qu Wenruo
2021-04-27 23:03 ` [Patch v2 25/42] btrfs: prevent extent_clear_unlock_delalloc() to unlock page not locked by __process_pages_contig() Qu Wenruo
2021-04-27 23:03 ` [Patch v2 26/42] btrfs: make btrfs_set_range_writeback() subpage compatible Qu Wenruo
2021-04-27 23:03 ` [Patch v2 27/42] btrfs: make __extent_writepage_io() only submit dirty range for subpage Qu Wenruo
2021-04-27 23:03 ` [Patch v2 28/42] btrfs: make btrfs_truncate_block() to be subpage compatible Qu Wenruo
2021-04-27 23:03 ` [Patch v2 29/42] btrfs: make btrfs_page_mkwrite() " Qu Wenruo
2021-04-27 23:03 ` [Patch v2 30/42] btrfs: reflink: make copy_inline_to_page() " Qu Wenruo
2021-04-27 23:03 ` [Patch v2 31/42] btrfs: fix the filemap_range_has_page() call in btrfs_punch_hole_lock_range() Qu Wenruo
2021-04-27 23:03 ` [Patch v2 32/42] btrfs: don't clear page extent mapped if we're not invalidating the full page Qu Wenruo
2021-04-27 23:03 ` [Patch v2 33/42] btrfs: extract relocation page read and dirty part into its own function Qu Wenruo
2021-04-27 23:03 ` [Patch v2 34/42] btrfs: make relocate_one_page() to handle subpage case Qu Wenruo
2021-04-27 23:03 ` Qu Wenruo [this message]
2021-04-27 23:03 ` [Patch v2 36/42] btrfs: disable inline extent creation for subpage Qu Wenruo
2021-05-04 4:28 ` Qu Wenruo
2021-04-27 23:03 ` [Patch v2 37/42] btrfs: skip validation for subpage read repair Qu Wenruo
2021-04-27 23:03 ` [Patch v2 38/42] btrfs: allow submit_extent_page() to do bio split for subpage Qu Wenruo
2021-04-27 23:03 ` [Patch v2 39/42] btrfs: reject raid5/6 fs " Qu Wenruo
2021-04-28 14:22 ` Neal Gompa
2021-04-28 23:11 ` Qu Wenruo
2021-05-12 22:04 ` David Sterba
2021-04-27 23:03 ` [Patch v2 40/42] btrfs: fix a crash caused by race between prepare_pages() and btrfs_releasepage() Qu Wenruo
2021-04-28 10:56 ` Filipe Manana
2021-04-27 23:03 ` [Patch v2 41/42] btrfs: fix the use-after-free bug in writeback subpage helper Qu Wenruo
2021-05-06 23:46 ` Qu Wenruo
2021-05-07 4:57 ` Ritesh Harjani
2021-05-07 5:14 ` Qu Wenruo
2021-05-10 8:38 ` Qu Wenruo
2021-05-10 12:29 ` Ritesh Harjani
2021-05-10 13:10 ` Qu Wenruo
2021-05-11 10:48 ` Ritesh Harjani
2021-05-11 11:15 ` Qu Wenruo
2021-05-12 1:49 ` Qu Wenruo
2021-05-12 7:09 ` Ritesh Harjani
2021-05-13 16:33 ` Ritesh Harjani
2021-05-13 21:36 ` Ritesh Harjani
2021-05-13 23:41 ` Qu Wenruo
2021-05-14 15:08 ` Ritesh Harjani
2021-05-14 17:53 ` Ritesh Harjani
2021-05-14 22:22 ` Qu Wenruo
2021-05-15 9:59 ` Ritesh Harjani
2021-05-15 10:15 ` Qu Wenruo
2021-05-25 4:43 ` Ritesh Harjani
2021-05-25 5:52 ` Qu Wenruo
2021-05-25 6:14 ` Qu Wenruo
2021-05-25 9:23 ` Ritesh Harjani
2021-05-25 9:45 ` Qu Wenruo
2021-05-25 9:49 ` Qu Wenruo
2021-05-25 10:20 ` Ritesh Harjani
2021-05-25 11:41 ` Qu Wenruo
2021-05-25 13:02 ` Ritesh Harjani
2021-05-26 5:29 ` Ritesh Harjani
2021-05-26 5:58 ` Qu Wenruo
2021-05-26 13:45 ` Ritesh Harjani
2021-05-28 8:26 ` Qu Wenruo
2021-05-28 8:59 ` Ritesh Harjani
2021-05-28 10:25 ` Qu Wenruo
2021-05-30 1:50 ` Qu Wenruo
2021-04-27 23:03 ` [Patch v2 42/42] btrfs: allow read-write for 4K sectorsize on 64K page size systems Qu Wenruo
2021-05-12 22:18 ` [Patch v2 00/42] btrfs: add data write support for subpage David Sterba
2021-05-12 23:48 ` Qu Wenruo
2021-05-13 2:21 ` Qu Wenruo
2021-05-13 22:54 ` David Sterba
2021-05-14 1:41 ` Qu Wenruo
2021-05-14 2:26 ` riteshh
2021-05-14 10:28 ` riteshh
2021-05-14 11:28 ` David Sterba
2021-05-14 14:38 ` riteshh
2021-05-14 11:30 ` David Sterba
2021-05-14 22:25 ` David Sterba
2021-05-14 22:45 ` Qu Wenruo
2021-05-14 23:05 ` David Sterba
2021-05-14 23:17 ` Qu Wenruo
2021-05-17 13:22 ` David Sterba
2021-05-17 23:20 ` Qu Wenruo
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