From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CCE5F175A67 for ; Sat, 18 Apr 2026 00:51:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776473478; cv=none; b=mTe1iLpIxSCAVJmCnLZ32WSVEEdkFyIJMHErIOGFe6cYSvi1ZVW+ErsvyyfZIuEBcVVCv+aeQ4IEThQ1FdWcWozR36ovx5UmqFvov1CUlck1BCoCxy9/lTC9EDI2s3fSX+++eKIjJsIRHTEb9DDYBGYa3oPf93aTznuosYeimfA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776473478; c=relaxed/simple; bh=DBDZWUEMLzf8IOAj2T6bVQUu+oEnsiGaIL67dCYyAAw=; h=Message-ID:Date:MIME-Version:Cc:Subject:To:References:From: In-Reply-To:Content-Type; b=QSPvKyoKiP07807upuraZGoQaMhgCGTEBUXPavU8sn4EujPsYHEPmD7DF22nUsFojJED7nleiWCyL9XVXJSufiFC6VCixWC5kihre63avyzfxV3xywdHMKmQ59tyX5VzKIXbNA3GkMNteSn3HaxBBYOXAFOnTmFZuljuI7Mn/H8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=SKo3YNy2; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="SKo3YNy2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E3573C19425; Sat, 18 Apr 2026 00:51:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776473478; bh=DBDZWUEMLzf8IOAj2T6bVQUu+oEnsiGaIL67dCYyAAw=; h=Date:Cc:Subject:To:References:From:In-Reply-To:From; b=SKo3YNy2omrp1P/by9xrVCGfnWN8b9cr4Aen1K0Ze8JVDbIn5HKntgvkK3jv5dFC/ ZB+OXka4cbwO3T1H6wrMY8YRQd1UyGmuFglspNzNJtnk/zZjjGgyk8kvwheIlCqH2J onCuxR3UExSAf9YyOCbl3W4IzxKsQ9vx4/9sSEJnGf8TIaZCVwc7RyFPgVM0HdEk1W uDi+UVgxx3bIUGC9qybOq19L1R1AxjmKddwijsPCa0S3zF4YjFKh6uY2lwDCeHq95N yUSd5P0fybrglXNf5UpVpxf8GWyT69SgglAsUOJy+7tpmkLom8cENNVrADllGgaReD WSdZDE4xhLIkg== Message-ID: Date: Sat, 18 Apr 2026 08:51:14 +0800 Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Cc: chao@kernel.org, Yongpeng Yang , stable@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Subject: Re: [f2fs-dev] [PATCH] f2fs: fix node_cnt race between extent node destroy and writeback To: Yongpeng Yang , Jaegeuk Kim References: <20260403144015.221811-3-monty_pavel@sina.com> <5c222edf-6888-4007-9240-9e7988b2dc71@sina.com> Content-Language: en-US From: Chao Yu In-Reply-To: <5c222edf-6888-4007-9240-9e7988b2dc71@sina.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 4/17/26 21:26, Yongpeng Yang wrote: > > On 4/17/26 17:00, Chao Yu via Linux-f2fs-devel wrote: >> On 4/3/26 22:40, Yongpeng Yang wrote: >>> From: Yongpeng Yang >>> >>> f2fs_destroy_extent_node() does not set FI_NO_EXTENT before clearing >>> extent nodes. When called from f2fs_drop_inode() with I_SYNC set, >>> concurrent kworker writeback can insert new extent nodes into the same >>> extent tree, racing with the destroy and triggering f2fs_bug_on() in >>> __destroy_extent_node(). The scenario is as follows: >>> >>> drop inode                            writeback >>>   - iput >>>    - f2fs_drop_inode  // I_SYNC set >>>     - f2fs_destroy_extent_node >>>      - __destroy_extent_node >>>       - while (node_cnt) { >>>          write_lock(&et->lock) >>>          __free_extent_tree >>>          write_unlock(&et->lock) >>>                                         - __writeback_single_inode >>>                                          - f2fs_outplace_write_data >>>                                           - f2fs_update_read_extent_cache >>>                                            - __update_extent_tree_range >>>                                             // FI_NO_EXTENT not set, >>>                                             // insert new extent node >>>         } // node_cnt == 0, exit while >>>       - f2fs_bug_on(node_cnt)  // node_cnt > 0 >>> >>> Additionally, __update_extent_tree_range() only checks FI_NO_EXTENT for >>> EX_READ type, leaving EX_BLOCK_AGE updates completely unprotected. >>> >>> This patch set FI_NO_EXTENT under et->lock in __destroy_extent_node(), >>> consistent with other callers (__update_extent_tree_range and >>> __drop_extent_tree) and check FI_NO_EXTENT for both EX_READ and >>> EX_BLOCK_AGE tree. >> >> I suffered below test failure, then I bisect to this change. >> >>     generic/475  84s ... [failed, exit status 1]- output mismatch (see / >> share/git/fstests/results//generic/475.out.bad) >>     --- tests/generic/475.out   2025-01-12 21:57:40.279440664 +0800 >>     +++ /share/git/fstests/results//generic/475.out.bad 2026-04-17 >> 12:08:28.000000000 +0800 >>     @@ -1,2 +1,6 @@ >>      QA output created by 475 >>      Silence is golden. >>     +mount: /mnt/scratch_f2fs: mount system call failed: Structure needs >> cleaning. >>     +       dmesg(1) may have more information after failed mount system >> call. >>     +mount failed >>     +(see /share/git/fstests/results//generic/475.full for details) >>     ... >>     (Run 'diff -u /share/git/fstests/tests/generic/475.out /share/git/ >> fstests/results//generic/475.out.bad'  to see the entire diff) >> >> >>     generic/388  73s ... [failed, exit status 1]- output mismatch (see / >> share/git/fstests/results//generic/388.out.bad) >>     --- tests/generic/388.out   2025-01-12 21:57:40.275440602 +0800 >>     +++ /share/git/fstests/results//generic/388.out.bad 2026-04-17 >> 11:58:05.000000000 +0800 >>     @@ -1,2 +1,6 @@ >>      QA output created by 388 >>      Silence is golden. >>     +mount: /mnt/scratch_f2fs: mount system call failed: Structure needs >> cleaning. >>     +       dmesg(1) may have more information after failed mount system >> call. >>     +cycle mount failed >>     +(see /share/git/fstests/results//generic/388.full for details) >>     ... >>     (Run 'diff -u /share/git/fstests/tests/generic/388.out /share/git/ >> fstests/results//generic/388.out.bad'  to see the entire diff) >> >> >>     F2FS-fs (dm-0): sanity_check_extent_cache: inode (ino=1761) extent >> info [220057, 57, 6] is incorrect, run fsck to fix >> >> I suspect we may miss any extent updates after we set FI_NO_EXTENT in >> __destroy_extent_node(), result in failing in sanity_check_extent_cache(). >> >> Can we just relocate f2fs_bug_on(node_cnt) rather than complicated change? >> Thoughts? > > Oh, I overlooked largest extent. How about relocate > f2fs_bug_on(node_cnt) to __destroy_extent_tree? > > static void __destroy_extent_tree(struct inode *inode, enum extent_type > type) > > /* free all extent info belong to this extent tree */ > node_cnt = __destroy_extent_node(inode, type); > + f2fs_bug_on(sbi, atomic_read(&et->node_cnt)); /* free all extent info belong to this extent tree */ node_cnt = __destroy_extent_node(inode, type); /* delete extent tree entry in radix tree */ mutex_lock(&eti->extent_tree_lock); f2fs_bug_on(sbi, atomic_read(&et->node_cnt)); <--- Oh, it has already checked node_cnt, so, maybe we can just remove the check in __destroy_extent_node()? Thanks, > > Thanks > Yongpeng, > >> >> Thanks, >> >>> >>> Fixes: 3fc5d5a182f6 ("f2fs: fix to shrink read extent node in batches") >>> Cc: stable@vger.kernel.org >>> Signed-off-by: Yongpeng Yang >>> --- >>>   fs/f2fs/extent_cache.c | 17 ++++++++++------- >>>   1 file changed, 10 insertions(+), 7 deletions(-) >>> >>> diff --git a/fs/f2fs/extent_cache.c b/fs/f2fs/extent_cache.c >>> index 0ed84cc065a7..87169fd29d89 100644 >>> --- a/fs/f2fs/extent_cache.c >>> +++ b/fs/f2fs/extent_cache.c >>> @@ -119,9 +119,10 @@ static bool __may_extent_tree(struct inode >>> *inode, enum extent_type type) >>>       if (!__init_may_extent_tree(inode, type)) >>>           return false; >>>   +    if (is_inode_flag_set(inode, FI_NO_EXTENT)) >>> +        return false; >>> + >>>       if (type == EX_READ) { >>> -        if (is_inode_flag_set(inode, FI_NO_EXTENT)) >>> -            return false; >>>           if (is_inode_flag_set(inode, FI_COMPRESSED_FILE) && >>>                    !f2fs_sb_has_readonly(F2FS_I_SB(inode))) >>>               return false; >>> @@ -644,6 +645,8 @@ static unsigned int __destroy_extent_node(struct >>> inode *inode, >>>         while (atomic_read(&et->node_cnt)) { >>>           write_lock(&et->lock); >>> +        if (!is_inode_flag_set(inode, FI_NO_EXTENT)) >>> +            set_inode_flag(inode, FI_NO_EXTENT); >>>           node_cnt += __free_extent_tree(sbi, et, nr_shrink); >>>           write_unlock(&et->lock); >>>       } >>> @@ -688,12 +691,12 @@ static void __update_extent_tree_range(struct >>> inode *inode, >>>         write_lock(&et->lock); >>>   -    if (type == EX_READ) { >>> -        if (is_inode_flag_set(inode, FI_NO_EXTENT)) { >>> -            write_unlock(&et->lock); >>> -            return; >>> -        } >>> +    if (is_inode_flag_set(inode, FI_NO_EXTENT)) { >>> +        write_unlock(&et->lock); >>> +        return; >>> +    } >>>   +    if (type == EX_READ) { >>>           prev = et->largest; >>>           dei.len = 0; >>> >> >> >> >> _______________________________________________ >> Linux-f2fs-devel mailing list >> Linux-f2fs-devel@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel >