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From:   David Howells <dhowells@redhat.com>
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References: <12153db1-20af-040b-ded0-31286b5bafca@kernel.org> <20230522135018.2742245-1-dhowells@redhat.com> <20230522135018.2742245-26-dhowells@redhat.com>
To:     Damien Le Moal <dlemoal@kernel.org>
Cc:     dhowells@redhat.com, Jens Axboe <axboe@kernel.dk>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Christoph Hellwig <hch@infradead.org>,
        Matthew Wilcox <willy@infradead.org>, Jan Kara <jack@suse.cz>,
        Jeff Layton <jlayton@kernel.org>,
        David Hildenbrand <david@redhat.com>,
        Jason Gunthorpe <jgg@nvidia.com>,
        Logan Gunthorpe <logang@deltatee.com>,
        Hillf Danton <hdanton@sina.com>,
        Christian Brauner <brauner@kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        Christoph Hellwig <hch@lst.de>,
        "Darrick J . Wong" <djwong@kernel.org>, linux-xfs@vger.kernel.org
Subject: Re: [PATCH v22 25/31] zonefs: Provide a splice-read wrapper
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Date:   Tue, 23 May 2023 21:43:14 +0100
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Damien Le Moal <dlemoal@kernel.org> wrote:

> > +	if (len > 0) {
> > +		ret =3D filemap_splice_read(in, ppos, pipe, len, flags);
> > +		if (ret =3D=3D -EIO)
> =

> Is -EIO the only error that filemap_splice_read() may return ? There are=
 other
> IO error codes that we could get from the block layer, e.g. -ETIMEDOUT e=
tc. So
> "if (ret < 0)" may be better here ?

It can return -ENOMEM, -EINTR and -EAGAIN at least, none of which really c=
ount
as I/O errors.  I based the splice function on what zonefs_file_read_iter(=
)
does:

	} else {
		ret =3D generic_file_read_iter(iocb, to);
		if (ret =3D=3D -EIO)
			zonefs_io_error(inode, false);
	}

David