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Date:   Mon, 10 Apr 2023 23:23:38 -0700
From:   Christoph Hellwig <hch@infradead.org>
To:     Donald Buczek <buczek@molgen.mpg.de>
Cc:     Sergei Shtepa <sergei.shtepa@veeam.com>, axboe@kernel.dk,
        hch@infradead.org, corbet@lwn.net, snitzer@kernel.org,
        viro@zeniv.linux.org.uk, brauner@kernel.org, willy@infradead.org,
        kch@nvidia.com, martin.petersen@oracle.com, vkoul@kernel.org,
        ming.lei@redhat.com, gregkh@linuxfoundation.org,
        linux-block@vger.kernel.org, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH v3 02/11] block: Block Device Filtering Mechanism
Message-ID: <ZDT86vCXcszoBh4e@infradead.org>
References: <20230404140835.25166-1-sergei.shtepa@veeam.com>
 <20230404140835.25166-3-sergei.shtepa@veeam.com>
 <be98bee0-4ddc-194f-82be-767e0bb9f60f@molgen.mpg.de>
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In-Reply-To: <be98bee0-4ddc-194f-82be-767e0bb9f60f@molgen.mpg.de>
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On Sat, Apr 08, 2023 at 05:16:42PM +0200, Donald Buczek wrote:
> Hi, Sergei,
> 
> On 4/4/23 16:08, Sergei Shtepa wrote:
> > The block device filtering mechanism is an API that allows to attach
> > block device filters. Block device filters allow perform additional
> > processing for I/O units.
> > [...]
> > diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
> > index b7b56871029c..1848d62979a4 100644
> > --- a/include/uapi/linux/fs.h
> > +++ b/include/uapi/linux/fs.h
> > @@ -185,6 +185,11 @@ struct fsxattr {
> >   #define BLKROTATIONAL _IO(0x12,126)
> >   #define BLKZEROOUT _IO(0x12,127)
> >   #define BLKGETDISKSEQ _IOR(0x12,128,__u64)
> > +/* 13* is defined in linux/blkzoned.h */
> 
> nit: This is already explained in the comment below your insert.

My faul.  But indeed, no need to duplicate that, instead the new
ioctl opcodes should move below that existing comment.