diff options
| author | Shaohua Li <shli@fb.com> | 2017-09-21 19:55:28 +0300 |
|---|---|---|
| committer | Shaohua Li <shli@fb.com> | 2017-09-28 06:08:18 +0300 |
| commit | 79bf31a3b2a7ca467cfec8ff97d359a77065d01f (patch) | |
| tree | 22d15c13f9a67ccd17b21c3077160b89a66c9c62 | |
| parent | 393debc23c7820211d1c8253dd6a8408a7628fe7 (diff) | |
| download | linux-79bf31a3b2a7ca467cfec8ff97d359a77065d01f.tar.xz | |
md: fix a race condition for flush request handling
md_submit_flush_data calls pers->make_request, which missed the suspend check.
Fix it with the new md_handle_request API.
Reported-by: Nate Dailey <nate.dailey@stratus.com>
Tested-by: Nate Dailey <nate.dailey@stratus.com>
Fix: cc27b0c78c79(md: fix deadlock between mddev_suspend() and md_write_start())
Cc: stable@vger.kernel.org
Reviewed-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
| -rw-r--r-- | drivers/md/md.c | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c index 1db1a22ed835..0ff1bbf6c90e 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -447,16 +447,22 @@ static void md_submit_flush_data(struct work_struct *ws) struct mddev *mddev = container_of(ws, struct mddev, flush_work); struct bio *bio = mddev->flush_bio; + /* + * must reset flush_bio before calling into md_handle_request to avoid a + * deadlock, because other bios passed md_handle_request suspend check + * could wait for this and below md_handle_request could wait for those + * bios because of suspend check + */ + mddev->flush_bio = NULL; + wake_up(&mddev->sb_wait); + if (bio->bi_iter.bi_size == 0) /* an empty barrier - all done */ bio_endio(bio); else { bio->bi_opf &= ~REQ_PREFLUSH; - mddev->pers->make_request(mddev, bio); + md_handle_request(mddev, bio); } - - mddev->flush_bio = NULL; - wake_up(&mddev->sb_wait); } void md_flush_request(struct mddev *mddev, struct bio *bio) |