linux-kernel - Re: [f2fs-dev] [PATCH] f2fs: ensure node page reads complete before f2fs_put

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Message-ID: <714ed524-8a2f-4409-9bda-15df07695d3c@kernel.org>
Date: Wed, 29 Oct 2025 09:59:26 +0800
From: Chao Yu <chao@...nel.org>
To: Jaegeuk Kim <jaegeuk@...nel.org>
Cc: chao@...nel.org, Jan Prusakowski <jprusakowski@...gle.com>,
 linux-kernel@...r.kernel.org, linux-f2fs-devel@...ts.sourceforge.net
Subject: Re: [f2fs-dev] [PATCH] f2fs: ensure node page reads complete before
 f2fs_put_super() finishes

On 10/29/25 02:06, Jaegeuk Kim wrote:
> Testing this patch:
> 
> Xfstests generic/335, generic/336 sometimes crash with the following message:
> 
> F2FS-fs (dm-0): detect filesystem reference count leak during umount, type: 9, count: 1
> ------------[ cut here ]------------
> kernel BUG at fs/f2fs/super.c:1939!
> Oops: invalid opcode: 0000 [#1] SMP NOPTI
> CPU: 1 UID: 0 PID: 609351 Comm: umount Tainted: G        W           6.17.0-rc5-xfstests-g9dd1835ecda5 #1 PREEMPT(none)
> Tainted: [W]=WARN
> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
> RIP: 0010:f2fs_put_super+0x3b3/0x3c0
> Call Trace:
>  <TASK>
>  generic_shutdown_super+0x7e/0x190
>  kill_block_super+0x1a/0x40
>  kill_f2fs_super+0x9d/0x190
>  deactivate_locked_super+0x30/0xb0
>  cleanup_mnt+0xba/0x150
>  task_work_run+0x5c/0xa0
>  exit_to_user_mode_loop+0xb7/0xc0
>  do_syscall_64+0x1ae/0x1c0
>  entry_SYSCALL_64_after_hwframe+0x76/0x7e
>  </TASK>
> ---[ end trace 0000000000000000 ]---
> 
> It appears that sometimes it is possible that f2fs_put_super() is called before
> all node page reads are completed.
> Adding a call to f2fs_wait_on_all_pages() for F2FS_RD_NODE fixes the problem.
> 
> Fixes: 20872584b8c0b ("f2fs: fix to drop all dirty meta/node pages during umount()")

Cc: stable@...nel.org

Otherwise it looks good to me.

> Signed-off-by: Jan Prusakowski <jprusakowski@...gle.com>
> Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>

Reviewed-by: Chao Yu <chao@...nel.org>

Thanks,

> ---
>  fs/f2fs/super.c | 17 +++++++++--------
>  1 file changed, 9 insertions(+), 8 deletions(-)
> 
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index bdb5ddb4f966..0b0ef8ba243b 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -1989,14 +1989,6 @@ static void f2fs_put_super(struct super_block *sb)
>  		truncate_inode_pages_final(META_MAPPING(sbi));
>  	}
>  
> -	for (i = 0; i < NR_COUNT_TYPE; i++) {
> -		if (!get_pages(sbi, i))
> -			continue;
> -		f2fs_err(sbi, "detect filesystem reference count leak during "
> -			"umount, type: %d, count: %lld", i, get_pages(sbi, i));
> -		f2fs_bug_on(sbi, 1);
> -	}
> -
>  	f2fs_bug_on(sbi, sbi->fsync_node_num);
>  
>  	f2fs_destroy_compress_inode(sbi);
> @@ -2007,6 +1999,15 @@ static void f2fs_put_super(struct super_block *sb)
>  	iput(sbi->meta_inode);
>  	sbi->meta_inode = NULL;
>  
> +	/* Should check the page counts after dropping all node/meta pages */
> +	for (i = 0; i < NR_COUNT_TYPE; i++) {
> +		if (!get_pages(sbi, i))
> +			continue;
> +		f2fs_err(sbi, "detect filesystem reference count leak during "
> +			"umount, type: %d, count: %lld", i, get_pages(sbi, i));
> +		f2fs_bug_on(sbi, 1);
> +	}
> +
>  	/*
>  	 * iput() can update stat information, if f2fs_write_checkpoint()
>  	 * above failed with error.