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From: Joshi <joshiiitr@gmail.com>
To: linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org,
	linux-btrfs@vger.kernel.org, linux-ext4@vger.kernel.org
Subject: cross-fs copy support
Date: Mon, 1 Oct 2018 20:02:17 +0530	[thread overview]
Message-ID: <CA+1E3rLXPwzfO3ro49ZVg7RfpYon5YDB6Y_zqu60ivpgn4wenw@mail.gmail.com> (raw)

I was wondering about the cross-fs copy through copy_file_range.
It seems current implement has below check, that disables such copy.

1577         /* this could be relaxed once a method supports cross-fs copies */
1578         if (inode_in->i_sb != inode_out->i_sb)
1579                 return -EXDEV;

May I know what are the thoughts behind disabling cross-fs copy?
Code has the comment "once a method supports", but that leaves me
wondering exactly what 'method' is expected, and from whom.

I disabled the check, and copy across volumes seemed to work fine. At
least for a single file (1G size), with no data mismatch, and faster
speed than regular copy.

-- 
Joshi

             reply	other threads:[~2018-10-01 21:10 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-01 14:32 Joshi [this message]
2018-10-01 14:48 ` Qu Wenruo
2018-10-01 15:15   ` Joshi
2018-10-01 15:49   ` Eric Sandeen
2018-10-01 19:51     ` Andreas Dilger
2018-10-02  8:15       ` David Sterba
2018-10-02 15:19         ` Darrick J. Wong
2018-10-02 18:28       ` J. Bruce Fields

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