jffs2: Hook up splice_write callback

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commit 42984af09a upstream.

overlayfs using jffs2 as the upper filesystem would fail in some cases
since moving to v5.10. The test case used was to run 'touch' on a file
that exists in the lower fs, causing the modification time to be
updated. It returns EINVAL when the bug is triggered.

A bisection showed this was introduced in v5.9-rc1, with commit
36e2c7421f ("fs: don't allow splice read/write without explicit ops").
Reverting that commit restores the expected behaviour.

Some digging showed that this was due to jffs2 lacking an implementation
of splice_write. (For unknown reasons the warn_unsupported that should
trigger was not displaying any output).

Adding this patch resolved the issue and the test now passes.

Cc: stable@vger.kernel.org
Fixes: 36e2c7421f ("fs: don't allow splice read/write without explicit ops")
Signed-off-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Lei YU <yulei.sh@bytedance.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

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Joel Stanley 2021-03-31 00:15:37 +10:30 • committed by Greg Kroah-Hartman

parent 72c282b109

commit 643243e318

1 changed files with 1 additions and 0 deletions

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fs/jffs2/file.c

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