From: Christoph Hellwig <hch@lst.de>
To: David Howells <dhowells@redhat.com>
Cc: hch@lst.de, linux-block@vger.kernel.org
Subject: Re: How best to get the size of a blockdev from a file?
Date: Tue, 18 Apr 2023 17:34:56 +0200 [thread overview]
Message-ID: <20230418153456.GA10282@lst.de> (raw)
In-Reply-To: <1609851.1681812012@warthog.procyon.org.uk>
On Tue, Apr 18, 2023 at 11:00:12AM +0100, David Howells wrote:
> Hi Christoph,
>
> It seems that my use of i_size_read(file_inode(in)) in filemap_splice_read()
> to get the size of the file to be spliced from doesn't work in the case of
> blockdevs and it always returns 0.
>
> What would be the best way to get the blockdev size? Look at
> file->f_mapping->i_size maybe?
Yes. Everything using an inode in generic read/write helpers always
needs to use file->f_mapping->host to get at the inode. Not just for
the size.
prev parent reply other threads:[~2023-04-18 15:41 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20230418100108epcas5p2d0f2a7a274e78731373986b3d4fced9b@epcas5p2.samsung.com>
2023-04-18 10:00 ` How best to get the size of a blockdev from a file? David Howells
2023-04-18 12:28 ` Kanchan Joshi
2023-04-18 14:05 ` Jason Yan
2023-04-20 19:04 ` Al Viro
2023-04-21 1:38 ` Jason Yan
2023-04-18 15:34 ` Christoph Hellwig [this message]
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