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md: fix a race condition for flush request handling

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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 <[email protected]>
Tested-by: Nate Dailey <[email protected]>
Fix: cc27b0c78c79(md: fix deadlock between mddev_suspend() and md_write_start())
Cc: [email protected]
Reviewed-by: NeilBrown <[email protected]>
Signed-off-by: Shaohua Li <[email protected]>
This commit is contained in:
Shaohua Li committed 2017-09-27 20:08:18 -07:00
1 parent 393debc23c
commit 79bf31a3b2
1 file changed
+10 -4
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drivers/md/md.c
+10 -4
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@@ -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)