fs/pipe: allow sendfile() to pipe again

commit f8ad8187c3b536ee2b10502a8340c014204a1af0 upstream.

After commit 36e2c7421f02 ("fs: don't allow splice read/write
without explicit ops") sendfile() could no longer send data
from a real file to a pipe, breaking for example certain cgit
setups (e.g. when running behind fcgiwrap), because in this
case cgit will try to do exactly this: sendfile() to a pipe.

Fix this by using iter_file_splice_write for the splice_write
method of pipes, as suggested by Christoph.

Cc: stable@vger.kernel.org
Fixes: 36e2c7421f02 ("fs: don't allow splice read/write without explicit ops")
Suggested-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/pipe.c b/fs/pipe.c
index 0ac1976..412b3b6 100644 (file)
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -1206,6 +1206,7 @@ const struct file_operations pipefifo_fops = {
        .unlocked_ioctl = pipe_ioctl,
        .release        = pipe_release,
        .fasync         = pipe_fasync,
+       .splice_write   = iter_file_splice_write,
 };
 
 /*