[PATCH 3.18 26/49] md/raid1: avoid reusing a resync bio after error handling.
From: Greg Kroah-Hartman
Date: Thu May 18 2017 - 09:29:00 EST
3.18-stable review patch. If anyone has any objections, please let me know.
From: NeilBrown <neilb@xxxxxxxx>
commit 0c9d5b127f695818c2c5a3868c1f28ca2969e905 upstream.
fix_sync_read_error() modifies a bio on a newly faulty
device by setting bi_end_io to end_sync_write.
This ensure that put_buf() will still call rdev_dec_pending()
as required, but makes sure that subsequent code in
fix_sync_read_error() doesn't try to read from the device.
Unfortunately this interacts badly with sync_request_write()
which assumes that any bio with bi_end_io set to non-NULL
other than end_sync_read is safe to write to.
As the device is now faulty it doesn't make sense to write.
As the bio was recently used for a read, it is "dirty"
and not suitable for immediate submission.
In particular, ->bi_next might be non-NULL, which will cause
generic_make_request() to complain.
Break this interaction by refusing to write to devices
which are marked as Faulty.
Reported-and-tested-by: Michael Wang <yun.wang@xxxxxxxxxxxxxxxx>
Fixes: 2e52d449bcec ("md/raid1: add failfast handling for reads.")
Signed-off-by: NeilBrown <neilb@xxxxxxxx>
Signed-off-by: Shaohua Li <shli@xxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
drivers/md/raid1.c | 2 ++
1 file changed, 2 insertions(+)
@@ -2067,6 +2067,8 @@ static void sync_request_write(struct md
(i == r1_bio->read_disk ||
+ if (test_bit(Faulty, &conf->mirrors[i].rdev->flags))
wbio->bi_rw = WRITE;
wbio->bi_end_io = end_sync_write;