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5032628c GKH |
1 | From 0c9d5b127f695818c2c5a3868c1f28ca2969e905 Mon Sep 17 00:00:00 2001 |
2 | From: NeilBrown <neilb@suse.com> | |
3 | Date: Thu, 6 Apr 2017 12:06:37 +1000 | |
4 | Subject: md/raid1: avoid reusing a resync bio after error handling. | |
5 | ||
6 | From: NeilBrown <neilb@suse.com> | |
7 | ||
8 | commit 0c9d5b127f695818c2c5a3868c1f28ca2969e905 upstream. | |
9 | ||
10 | fix_sync_read_error() modifies a bio on a newly faulty | |
11 | device by setting bi_end_io to end_sync_write. | |
12 | This ensure that put_buf() will still call rdev_dec_pending() | |
13 | as required, but makes sure that subsequent code in | |
14 | fix_sync_read_error() doesn't try to read from the device. | |
15 | ||
16 | Unfortunately this interacts badly with sync_request_write() | |
17 | which assumes that any bio with bi_end_io set to non-NULL | |
18 | other than end_sync_read is safe to write to. | |
19 | ||
20 | As the device is now faulty it doesn't make sense to write. | |
21 | As the bio was recently used for a read, it is "dirty" | |
22 | and not suitable for immediate submission. | |
23 | In particular, ->bi_next might be non-NULL, which will cause | |
24 | generic_make_request() to complain. | |
25 | ||
26 | Break this interaction by refusing to write to devices | |
27 | which are marked as Faulty. | |
28 | ||
29 | Reported-and-tested-by: Michael Wang <yun.wang@profitbricks.com> | |
30 | Fixes: 2e52d449bcec ("md/raid1: add failfast handling for reads.") | |
31 | Signed-off-by: NeilBrown <neilb@suse.com> | |
32 | Signed-off-by: Shaohua Li <shli@fb.com> | |
33 | Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> | |
34 | ||
35 | --- | |
36 | drivers/md/raid1.c | 2 ++ | |
37 | 1 file changed, 2 insertions(+) | |
38 | ||
39 | --- a/drivers/md/raid1.c | |
40 | +++ b/drivers/md/raid1.c | |
41 | @@ -2222,6 +2222,8 @@ static void sync_request_write(struct md | |
42 | (i == r1_bio->read_disk || | |
43 | !test_bit(MD_RECOVERY_SYNC, &mddev->recovery)))) | |
44 | continue; | |
45 | + if (test_bit(Faulty, &conf->mirrors[i].rdev->flags)) | |
46 | + continue; | |
47 | ||
48 | bio_set_op_attrs(wbio, REQ_OP_WRITE, 0); | |
49 | if (test_bit(FailFast, &conf->mirrors[i].rdev->flags)) |