Re: [PATCH v8] vfs: fix copy_file_range regression in cross-fs copies
From: Nicolas Boichat
Date: Wed Feb 24 2021 - 05:47:24 EST
On Wed, Feb 24, 2021 at 6:22 PM Luis Henriques <lhenriques@xxxxxxx> wrote:
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On Tue, Feb 23, 2021 at 08:00:54PM -0500, Olga Kornievskaia wrote:
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> On Mon, Feb 22, 2021 at 5:25 AM Luis Henriques <lhenriques@xxxxxxx> wrote:
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> > A regression has been reported by Nicolas Boichat, found while using the
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> > copy_file_range syscall to copy a tracefs file. Before commit
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> > 5dae222a5ff0 ("vfs: allow copy_file_range to copy across devices") the
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> > kernel would return -EXDEV to userspace when trying to copy a file across
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> > different filesystems. After this commit, the syscall doesn't fail anymore
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> > and instead returns zero (zero bytes copied), as this file's content is
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> > generated on-the-fly and thus reports a size of zero.
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> >
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> > This patch restores some cross-filesystem copy restrictions that existed
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> > prior to commit 5dae222a5ff0 ("vfs: allow copy_file_range to copy across
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> > devices"). Filesystems are still allowed to fall-back to the VFS
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> > generic_copy_file_range() implementation, but that has now to be done
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> > explicitly.
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> > nfsd is also modified to fall-back into generic_copy_file_range() in case
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> > vfs_copy_file_range() fails with -EOPNOTSUPP or -EXDEV.
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> > Fixes: 5dae222a5ff0 ("vfs: allow copy_file_range to copy across devices")
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> > Link: https://lore.kernel.org/linux-fsdevel/20210212044405.4120619-1-drinkcat@xxxxxxxxxxxx/
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> > Link: https://lore.kernel.org/linux-fsdevel/CANMq1KDZuxir2LM5jOTm0xx+BnvW=ZmpsG47CyHFJwnw7zSX6Q@xxxxxxxxxxxxxx/
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> > Link: https://lore.kernel.org/linux-fsdevel/20210126135012.1.If45b7cdc3ff707bc1efa17f5366057d60603c45f@changeid/
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> > Reported-by: Nicolas Boichat <drinkcat@xxxxxxxxxxxx>
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> > Signed-off-by: Luis Henriques <lhenriques@xxxxxxx>
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> I tested v8 and I believe it works for NFS.
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Thanks a lot for the testing. And to everyone else for reviews,
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feedback,... and patience.
Thanks so much to you!!!
Works here, you can add my
Tested-by: Nicolas Boichat <drinkcat@xxxxxxxxxxxx>
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I'll now go look into the manpage and see what needs to be changed.
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Cheers,
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Luís