Messages in this thread | | | Date | Tue, 7 Jul 2020 22:29:35 -0400 | From | Sasha Levin <> | Subject | Re: [PATCH 4.19 10/36] nvme: fix possible deadlock when I/O is blocked |
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On Tue, Jul 07, 2020 at 08:16:41PM +0200, Pavel Machek wrote: >Hi! > >> From: Sagi Grimberg <sagi@grimberg.me> >> >> [ Upstream commit 3b4b19721ec652ad2c4fe51dfbe5124212b5f581 ] >> >> Revert fab7772bfbcf ("nvme-multipath: revalidate nvme_ns_head gendisk >> in nvme_validate_ns") >> >> When adding a new namespace to the head disk (via nvme_mpath_set_live) >> we will see partition scan which triggers I/O on the mpath device node. >> This process will usually be triggered from the scan_work which holds >> the scan_lock. If I/O blocks (if we got ana change currently have only >> available paths but none are accessible) this can deadlock on the head >> disk bd_mutex as both partition scan I/O takes it, and head disk revalidation >> takes it to check for resize (also triggered from scan_work on a different >> path). See trace [1]. >> >> The mpath disk revalidation was originally added to detect online disk >> size change, but this is no longer needed since commit cb224c3af4df >> ("nvme: Convert to use set_capacity_revalidate_and_notify") which >> already > >AFAICT cb224c3af4df is not applied to 4.19-stable series, so this is >not safe according to the changelog. > >cb224c3af4df is simple enough, but AFAICT >set_capacity_revalidate_and_notify() is missing in 4.19.132-rc1.
Good point... It might be the case that e598a72faeb5 ("block/genhd: Notify udev about capacity change") is safe to take along with cb224c3af4df.
I'll look at it once these releases are out, but for now I'll drop this commit. Thanks!
-- Thanks, Sasha
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