Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 3.18 26/49] md/raid1: avoid reusing a resync bio after error handling. | Date | Thu, 18 May 2017 15:16:35 +0200 |
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3.18-stable review patch. If anyone has any objections, please let me know.
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From: NeilBrown <neilb@suse.com>
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@profitbricks.com> Fixes: 2e52d449bcec ("md/raid1: add failfast handling for reads.") Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/md/raid1.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -2067,6 +2067,8 @@ static void sync_request_write(struct md (i == r1_bio->read_disk || !test_bit(MD_RECOVERY_SYNC, &mddev->recovery)))) continue; + if (test_bit(Faulty, &conf->mirrors[i].rdev->flags)) + continue; wbio->bi_rw = WRITE; wbio->bi_end_io = end_sync_write;
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