From: Qu Wenruo <quwenruo.btrfs@gmx.com>
To: Naohiro Aota <naohiro.aota@wdc.com>, linux-btrfs@vger.kernel.org
Cc: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Subject: Re: [PATCH] btrfs: fix invalid mapping xarray state
Date: Fri, 9 Aug 2024 17:28:40 +0930 [thread overview]
Message-ID: <813a933c-9358-4ece-9e59-897900642628@gmx.com> (raw)
In-Reply-To: <cb40bca119cc0519bb5e17f6a9060a35a839ea28.1723189951.git.naohiro.aota@wdc.com>
在 2024/8/9 17:24, Naohiro Aota 写道:
> In __extent_writepage_io(), we call btrfs_set_range_writeback() ->
> folio_start_writeback(), which clears PAGECACHE_TAG_DIRTY mark from the
> mapping xarray if the folio is not dirty. This worked fine before commit
> 97713b1a2ced ("btrfs: do not clear page dirty inside
> extent_write_locked_range()").
>
> After the commit, however, the folio is still dirty at this point, so the
> mapping DIRTY tag is not cleared anymore. Then, __extent_writepage_io()
> calls btrfs_folio_clear_dirty() to clear the folio's dirty flag. That
> results in the page beging unlocked with a "strange" state. The page is not
> PageDirty, but the mapping tag is set as PAGECACHE_TAG_DIRTY.
>
> This strange state looks like causing a hang with a call trace below when
> running fstests generic/091 on a null_blk device. It is waiting for a folio
> lock.
>
> While I don't have an exact relation between this hang and the strange
> state, fixing the state also fixes the hang. And, that state is worth
> fixing anyway.
>
> This commit reorders btrfs_folio_clear_dirty() and
> btrfs_set_range_writeback() in __extent_writepage_io(), so that the
> PAGECACHE_TAG_DIRTY tag is properly removed from the xarray.
>
> [ 2464.274674][ T245] task:fsx state:D stack:0 pid:3034 tgid:3034 ppid:2853 flags:0x00004002
> [ 2464.286991][ T245] Call Trace:
> [ 2464.291683][ T245] <TASK>
> [ 2464.295876][ T245] __schedule+0x10ed/0x6260
> [ 2464.301804][ T245] ? __pfx___blk_flush_plug+0x10/0x10
> [ 2464.308703][ T245] ? __submit_bio+0x37c/0x450
> [ 2464.314833][ T245] ? __pfx___schedule+0x10/0x10
> [ 2464.321245][ T245] ? lock_release+0x567/0x790
> [ 2464.327480][ T245] ? __pfx_lock_acquire+0x10/0x10
> [ 2464.334033][ T245] ? __pfx_lock_release+0x10/0x10
> [ 2464.340674][ T245] ? __pfx_lock_acquire+0x10/0x10
> [ 2464.347254][ T245] ? __pfx_lock_release+0x10/0x10
> [ 2464.353732][ T245] ? do_raw_spin_lock+0x12e/0x270
> [ 2464.360305][ T245] schedule+0xdf/0x3b0
> [ 2464.365705][ T245] io_schedule+0x8f/0xf0
> [ 2464.371417][ T245] folio_wait_bit_common+0x2ca/0x6d0
> [ 2464.378260][ T245] ? folio_wait_bit_common+0x1cc/0x6d0
> [ 2464.385314][ T245] ? __pfx_folio_wait_bit_common+0x10/0x10
> [ 2464.392658][ T245] ? __pfx_filemap_get_folios_tag+0x10/0x10
> [ 2464.400173][ T245] ? __pfx_wake_page_function+0x10/0x10
> [ 2464.407309][ T245] ? __pfx___might_resched+0x10/0x10
> [ 2464.414120][ T245] ? do_raw_spin_unlock+0x58/0x1f0
> [ 2464.420688][ T245] extent_write_cache_pages+0xe49/0x1620 [btrfs]
> [ 2464.428894][ T245] ? lock_acquire+0x435/0x500
> [ 2464.435024][ T245] ? __pfx_extent_write_cache_pages+0x10/0x10 [btrfs]
> [ 2464.443736][ T245] ? btrfs_do_write_iter+0x493/0x640 [btrfs]
> [ 2464.451523][ T245] ? orc_find.part.0+0x1d4/0x380
> [ 2464.457938][ T245] ? __pfx_lock_release+0x10/0x10
> [ 2464.464544][ T245] ? __pfx_lock_release+0x10/0x10
> [ 2464.471066][ T245] ? btrfs_do_write_iter+0x493/0x640 [btrfs]
> [ 2464.478722][ T245] btrfs_writepages+0x1cc/0x460 [btrfs]
> [ 2464.485913][ T245] ? __pfx_btrfs_writepages+0x10/0x10 [btrfs]
> [ 2464.493675][ T245] ? is_bpf_text_address+0x6e/0x100
> [ 2464.500476][ T245] ? kernel_text_address+0x145/0x160
> [ 2464.507359][ T245] ? unwind_get_return_address+0x5e/0xa0
> [ 2464.514709][ T245] ? arch_stack_walk+0xac/0x100
> [ 2464.521090][ T245] do_writepages+0x176/0x780
> [ 2464.527189][ T245] ? lock_release+0x567/0x790
> [ 2464.533402][ T245] ? __pfx_do_writepages+0x10/0x10
> [ 2464.540069][ T245] ? __pfx_lock_acquire+0x10/0x10
> [ 2464.546724][ T245] ? __pfx_stack_trace_save+0x10/0x10
> [ 2464.553598][ T245] ? do_raw_spin_lock+0x12e/0x270
> [ 2464.560158][ T245] ? do_raw_spin_unlock+0x58/0x1f0
> [ 2464.566760][ T245] ? _raw_spin_unlock+0x23/0x40
> [ 2464.573105][ T245] ? wbc_attach_and_unlock_inode+0x3da/0x7d0
> [ 2464.580664][ T245] filemap_fdatawrite_wbc+0x113/0x180
> [ 2464.587706][ T245] ? prepare_pages.constprop.0+0x13c/0x5c0 [btrfs]
> [ 2464.596015][ T245] __filemap_fdatawrite_range+0xaf/0xf0
> [ 2464.603159][ T245] ? __pfx___filemap_fdatawrite_range+0x10/0x10
> [ 2464.611102][ T245] ? trace_irq_enable.constprop.0+0xce/0x110
> [ 2464.618689][ T245] ? kasan_quarantine_put+0xd7/0x1e0
> [ 2464.625641][ T245] btrfs_start_ordered_extent+0x46f/0x570 [btrfs]
> [ 2464.633843][ T245] ? __pfx_btrfs_start_ordered_extent+0x10/0x10 [btrfs]
> [ 2464.642777][ T245] ? __clear_extent_bit+0x2c0/0x9d0 [btrfs]
> [ 2464.650522][ T245] btrfs_lock_and_flush_ordered_range+0xc6/0x180 [btrfs]
> [ 2464.659525][ T245] ? __pfx_btrfs_lock_and_flush_ordered_range+0x10/0x10 [btrfs]
> [ 2464.669173][ T245] btrfs_read_folio+0x12a/0x1d0 [btrfs]
> [ 2464.676520][ T245] ? __pfx_btrfs_read_folio+0x10/0x10 [btrfs]
> [ 2464.684449][ T245] ? __pfx_filemap_add_folio+0x10/0x10
> [ 2464.691733][ T245] ? __pfx___might_resched+0x10/0x10
> [ 2464.698736][ T245] ? __filemap_get_folio+0x1c5/0x450
> [ 2464.705739][ T245] prepare_uptodate_page+0x12e/0x4d0 [btrfs]
> [ 2464.713624][ T245] prepare_pages.constprop.0+0x13c/0x5c0 [btrfs]
> [ 2464.721758][ T245] ? fault_in_iov_iter_readable+0xd2/0x240
> [ 2464.729292][ T245] btrfs_buffered_write+0x5bd/0x12f0 [btrfs]
> [ 2464.737106][ T245] ? __pfx_btrfs_buffered_write+0x10/0x10 [btrfs]
> [ 2464.745448][ T245] ? __pfx_lock_release+0x10/0x10
> [ 2464.752085][ T245] ? generic_write_checks+0x275/0x400
> [ 2464.759126][ T245] ? down_write+0x118/0x1f0
> [ 2464.765188][ T245] ? up_write+0x19b/0x500
> [ 2464.770947][ T245] btrfs_direct_write+0x731/0xba0 [btrfs]
> [ 2464.778148][ T245] ? __pfx_btrfs_direct_write+0x10/0x10 [btrfs]
> [ 2464.785902][ T245] ? __pfx___might_resched+0x10/0x10
> [ 2464.792460][ T245] ? lock_acquire+0x435/0x500
> [ 2464.798466][ T245] ? lock_acquire+0x435/0x500
> [ 2464.804450][ T245] btrfs_do_write_iter+0x494/0x640 [btrfs]
> [ 2464.811630][ T245] ? __pfx_btrfs_do_write_iter+0x10/0x10 [btrfs]
> [ 2464.819386][ T245] ? __pfx___might_resched+0x10/0x10
> [ 2464.825952][ T245] ? rw_verify_area+0x6d/0x590
> [ 2464.831937][ T245] vfs_write+0x5d7/0xf50
> [ 2464.837412][ T245] ? __might_fault+0x9d/0x120
> [ 2464.843363][ T245] ? __pfx_vfs_write+0x10/0x10
> [ 2464.849417][ T245] ? btrfs_file_llseek+0xb1/0xfb0 [btrfs]
> [ 2464.856493][ T245] ? lock_release+0x567/0x790
> [ 2464.862348][ T245] ksys_write+0xfb/0x1d0
> [ 2464.867723][ T245] ? __pfx_ksys_write+0x10/0x10
> [ 2464.873781][ T245] ? _raw_spin_unlock+0x23/0x40
> [ 2464.879858][ T245] ? btrfs_getattr+0x4af/0x670 [btrfs]
> [ 2464.886649][ T245] ? vfs_getattr_nosec+0x79/0x340
> [ 2464.892929][ T245] do_syscall_64+0x95/0x180
> [ 2464.898578][ T245] ? __do_sys_newfstat+0xde/0xf0
> [ 2464.904728][ T245] ? __pfx___do_sys_newfstat+0x10/0x10
> [ 2464.911454][ T245] ? trace_irq_enable.constprop.0+0xce/0x110
> [ 2464.918797][ T245] ? syscall_exit_to_user_mode+0xac/0x2a0
> [ 2464.925851][ T245] ? do_syscall_64+0xa1/0x180
> [ 2464.931715][ T245] ? trace_irq_enable.constprop.0+0xce/0x110
> [ 2464.939106][ T245] ? trace_irq_enable.constprop.0+0xce/0x110
> [ 2464.946406][ T245] ? syscall_exit_to_user_mode+0xac/0x2a0
> [ 2464.953501][ T245] ? btrfs_file_llseek+0xb1/0xfb0 [btrfs]
> [ 2464.960625][ T245] ? do_syscall_64+0xa1/0x180
> [ 2464.966482][ T245] ? btrfs_file_llseek+0xb1/0xfb0 [btrfs]
> [ 2464.973570][ T245] ? trace_irq_enable.constprop.0+0xce/0x110
> [ 2464.980915][ T245] ? syscall_exit_to_user_mode+0xac/0x2a0
> [ 2464.987978][ T245] ? __pfx_btrfs_file_llseek+0x10/0x10 [btrfs]
> [ 2464.995542][ T245] ? trace_irq_enable.constprop.0+0xce/0x110
> [ 2465.002901][ T245] ? __pfx_btrfs_file_llseek+0x10/0x10 [btrfs]
> [ 2465.010462][ T245] ? do_syscall_64+0xa1/0x180
> [ 2465.016429][ T245] ? lock_release+0x567/0x790
> [ 2465.022388][ T245] ? __pfx_lock_acquire+0x10/0x10
> [ 2465.028622][ T245] ? __pfx_lock_release+0x10/0x10
> [ 2465.034894][ T245] ? trace_irq_enable.constprop.0+0xce/0x110
> [ 2465.042309][ T245] ? syscall_exit_to_user_mode+0xac/0x2a0
> [ 2465.049458][ T245] ? do_syscall_64+0xa1/0x180
> [ 2465.055421][ T245] ? syscall_exit_to_user_mode+0xac/0x2a0
> [ 2465.062429][ T245] ? do_syscall_64+0xa1/0x180
> [ 2465.068391][ T245] ? syscall_exit_to_user_mode+0xac/0x2a0
> [ 2465.075416][ T245] ? do_syscall_64+0xa1/0x180
> [ 2465.081383][ T245] ? clear_bhb_loop+0x25/0x80
> [ 2465.087346][ T245] ? clear_bhb_loop+0x25/0x80
> [ 2465.093282][ T245] ? clear_bhb_loop+0x25/0x80
> [ 2465.099197][ T245] entry_SYSCALL_64_after_hwframe+0x76/0x7e
> [ 2465.106399][ T245] RIP: 0033:0x7f093b8ee784
> [ 2465.111990][ T245] RSP: 002b:00007ffc29d31b28 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
> [ 2465.122130][ T245] RAX: ffffffffffffffda RBX: 0000000000006000 RCX: 00007f093b8ee784
> [ 2465.131698][ T245] RDX: 000000000001de00 RSI: 00007f093b6ed200 RDI: 0000000000000003
> [ 2465.141390][ T245] RBP: 000000000001de00 R08: 0000000000006000 R09: 0000000000000000
> [ 2465.150994][ T245] R10: 0000000000023e00 R11: 0000000000000202 R12: 0000000000006000
> [ 2465.160533][ T245] R13: 0000000000023e00 R14: 0000000000023e00 R15: 0000000000000001
> [ 2465.170157][ T245] </TASK>
> [ 2465.174240][ T245] INFO: lockdep is turned off.
>
> Reported-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
> Fixes: 97713b1a2ced ("btrfs: do not clear page dirty inside extent_write_locked_range()")
Reviewed-by: Qu Wenruo <wqu@suse.com>
Thanks for exposing and fixing the bug.
Qu
> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
> ---
> fs/btrfs/extent_io.c | 14 +++++++-------
> 1 file changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
> index 040c92541bc9..271a1ad9fe88 100644
> --- a/fs/btrfs/extent_io.c
> +++ b/fs/btrfs/extent_io.c
> @@ -1478,6 +1478,13 @@ static noinline_for_stack int __extent_writepage_io(struct btrfs_inode *inode,
> free_extent_map(em);
> em = NULL;
>
> + /*
> + * Although the PageDirty bit might be cleared before entering
> + * this function, subpage dirty bit is not cleared.
> + * So clear subpage dirty bit here so next time we won't submit
> + * page for range already written to disk.
> + */
> + btrfs_folio_clear_dirty(fs_info, folio, cur, iosize);
> btrfs_set_range_writeback(inode, cur, cur + iosize - 1);
> if (!folio_test_writeback(folio)) {
> btrfs_err(inode->root->fs_info,
> @@ -1485,13 +1492,6 @@ static noinline_for_stack int __extent_writepage_io(struct btrfs_inode *inode,
> folio->index, cur, end);
> }
>
> - /*
> - * Although the PageDirty bit is cleared before entering this
> - * function, subpage dirty bit is not cleared.
> - * So clear subpage dirty bit here so next time we won't submit
> - * folio for range already written to disk.
> - */
> - btrfs_folio_clear_dirty(fs_info, folio, cur, iosize);
>
> submit_extent_folio(bio_ctrl, disk_bytenr, folio,
> iosize, cur - folio_pos(folio));
next prev parent reply other threads:[~2024-08-09 7:58 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-08-09 7:54 [PATCH] btrfs: fix invalid mapping xarray state Naohiro Aota
2024-08-09 7:58 ` Qu Wenruo [this message]
2024-08-09 15:08 ` David Sterba
2024-08-12 5:17 ` Qu Wenruo
2024-08-13 13:36 ` David Sterba
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