Date:   Mon, 6 Mar 2023 17:16:22 +0100
From:   Jan Kara <jack@suse.cz>
To:     Chuck Lever <cel@kernel.org>
Cc:     linux-nfs@vger.kernel.org, jack@suse.de, flole@flole.de
Subject: Re: [PATCH] NFSD: Protect against filesystem freezing
Message-ID: <20230306161622.olratc7w5df4gc2d@quack3>
References: <167811742782.1909.380332356774647144.stgit@bazille.1015granger.net>
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On Mon 06-03-23 10:43:47, Chuck Lever wrote:
> From: Chuck Lever <chuck.lever@oracle.com>
> 
> Flole observes this WARNING on occasion:
> 
> [1210423.486503] WARNING: CPU: 8 PID: 1524732 at fs/ext4/ext4_jbd2.c:75 ext4_journal_check_start+0x68/0xb0
> 
> Reported-by: <flole@flole.de>
> Suggested-by: Jan Kara <jack@suse.cz>
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=217123
> Fixes: 73da852e3831 ("nfsd: use vfs_iter_read/write")
> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Looks good to me. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  fs/nfsd/vfs.c |    2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
> index 21d5209f6e04..ba34a31a7c70 100644
> --- a/fs/nfsd/vfs.c
> +++ b/fs/nfsd/vfs.c
> @@ -1104,7 +1104,9 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf,
>  	since = READ_ONCE(file->f_wb_err);
>  	if (verf)
>  		nfsd_copy_write_verifier(verf, nn);
> +	file_start_write(file);
>  	host_err = vfs_iter_write(file, &iter, &pos, flags);
> +	file_end_write(file);
>  	if (host_err < 0) {
>  		nfsd_reset_write_verifier(nn);
>  		trace_nfsd_writeverf_reset(nn, rqstp, host_err);
> 
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR