This is a note to let you know that I've just added the patch titled
md: multipath: don't hardcopy bio in .make_request path
to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
md-multipath-don-t-hardcopy-bio-in-.make_request-path.patch
and it can be found in the queue-3.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From fafcde3ac1a418688a734365203a12483b83907a Mon Sep 17 00:00:00 2001
From: Ming Lei <ming.lei@xxxxxxxxxxxxx>
Date: Sat, 12 Mar 2016 09:29:40 +0800
Subject: md: multipath: don't hardcopy bio in .make_request path
From: Ming Lei <ming.lei@xxxxxxxxxxxxx>
commit fafcde3ac1a418688a734365203a12483b83907a upstream.
Inside multipath_make_request(), multipath maps the incoming
bio into low level device's bio, but it is totally wrong to
copy the bio into mapped bio via '*mapped_bio = *bio'. For
example, .__bi_remaining is kept in the copy, especially if
the incoming bio is chained to via bio splitting, so .bi_end_io
can't be called for the mapped bio at all in the completing path
in this kind of situation.
This patch fixes the issue by using clone style.
Reported-and-tested-by: Andrea Righi <righi.andrea@xxxxxxxxx>
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxxxxx>
Signed-off-by: Shaohua Li <shli@xxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/md/multipath.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/md/multipath.c
+++ b/drivers/md/multipath.c
@@ -131,7 +131,9 @@ static void multipath_make_request(struc
}
multipath = conf->multipaths + mp_bh->path;
- mp_bh->bio = *bio;
+ bio_init(&mp_bh->bio);
+ __bio_clone_fast(&mp_bh->bio, bio);
+
mp_bh->bio.bi_iter.bi_sector += multipath->rdev->data_offset;
mp_bh->bio.bi_bdev = multipath->rdev->bdev;
mp_bh->bio.bi_rw |= REQ_FAILFAST_TRANSPORT;
Patches currently in stable-queue which might be from ming.lei@xxxxxxxxxxxxx are
queue-3.14/md-multipath-don-t-hardcopy-bio-in-.make_request-path.patch
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