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authorShaohua Li <shli@fb.com>2017-09-21 19:55:28 +0300
committerShaohua Li <shli@fb.com>2017-09-28 06:08:18 +0300
commit79bf31a3b2a7ca467cfec8ff97d359a77065d01f (patch)
tree22d15c13f9a67ccd17b21c3077160b89a66c9c62
parent393debc23c7820211d1c8253dd6a8408a7628fe7 (diff)
downloadlinux-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.c14
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)